Plasma activation of N-2, CH4 and CO2: an assessment of the vibrational non-equilibrium time window

Vibrational excitation potentially enhances the energy efficiency of plasma dissociation of stable molecules and may open new routes for energy storage and process electrification. Electron, vibrational and rotational temperatures were measured by in situ Thomson and Raman scattering in order to assess the opportunities and limitations of the essential vibration-translation non-equilibria in N-2, CO2 and CH4 plasma. Electron temperatures of 1.1-2.8 eV were measured in N-2 and CH4. These are used to confirm predominant energy transfer to vibrations after an initial phase of significant electronic excitation and ionization. The vibrational temperatures initially exceed rotational temperatures by almost 8000 K in N-2, by 900 K in CO2, and by 300 K in CH4. Equilibration is observed at the 0.1 ms timescale. Based on the vibrational temperatures, the vibrational loss rates for different channels are estimated. In N-2, vibrational quenching via N atoms is identified as the dominant equilibration mechanism. Atomic nitrogen population reaches a mole fraction of more than 1%, as inferred from the afterglow emission decay, and explains a gas heating rate of 25 K mu s(-1). CH4 equilibration at 1200 K is predominantly caused by vibrational-translational relaxation in CH4-CH4 collisions. As for CO2, vibrational-translational relaxation via parent molecules is responsible for a large fraction of the observed heating, whereas product-mediated VT relaxation is not significantly contributing. It is suggested that electronic excitation, followed by dissociation or quenching contributes to the remaining heat generation. In conclusion, the time window to profit from vibrational excitation under the present conditions is limiting practical application.</p

The Chemical Origins of Plasma Contraction and Thermalization in CO2 Microwave Discharges

Thermalization of electron and gas temperature in CO2 microwave plasma is unveiled with the first Thomson scattering measurements. The results contradict the prevalent picture of an increasing electron temperature that causes discharge contraction. It is known that as pressure increases, the radial extension of the plasma reduces from ∼7 mm diameter at 100 mbar to ∼2 mm at 400 mbar. We find that, simultaneously, the initial nonequilibrium between ∼2 eV electron and ∼0.5 eV gas temperature reduces until thermalization occurs at 0.6 eV. 1D fluid modeling, with excellent agreement with measurements, demonstrates that associative ionization of radicals, a mechanism previously proposed for air plasma, causes the thermalization. In effect, heavy particle and heat transport and thermal chemistry govern electron dynamics, a conclusion that provides a basis for ab initio prediction of power concentration in plasma reactors.</p

Temporal difference learning for the game Tic-Tac-Toe 3D: Applying structure to neural networks

When reinforcement learning is applied to large state spaces, such as those occurring in playing board games, the use of a good function approximator to learn to approximate the value function is very important. In previous research, multi-layer perceptrons have often been quite successfully used as function approximator for learning to play particular games with temporal difference learning. With the recent developments in deep learning, it is important to study if using multiple hidden layers or particular network structures can help to improve learning the value function. In this paper, we compare five different structures of multilayer perceptrons for learning to play the game Tic-Tac-Toe 3D, both when training through self-play and when training against the same fixed opponent they are tested against. We compare three fully connected multilayer perceptrons with a different number of hidden layers and/or hidden units, as well as two structured ones. These structured multilayer perceptrons have a first hidden layer that is only sparsely connected to the input layer, and has units that correspond to the rows in Tic-Tac-Toe 3D. This allows them to more easily learn the contribution of specific patterns on the corresponding rows. One of the two structured multilayer perceptrons has a second hidden layer that is fully connected to the first one, which allows the neural network to learn to non-linearly integrate the information in these detected patterns. The results on Tic-Tac-Toe 3D show that the deep structured neural network with integrated pattern detectors has the strongest performance out of the compared multilayer perceptrons against a fixed opponent, both through self-training and through training against this fixed opponent

Flame bands: CO + O chemiluminescence as a measure of gas temperature

Carbon monoxide flame band emission (CO+O → CO2+hV) in CO2 microwave plasma is quantified by obtaining absolute calibrated emission spectra at various locations in the plasma afterglow while simultaneously measuring gas temperatures using rotational Raman scattering. Comparison of our results to literature reveals a contribution of O2 Schumann-Runge UV emission at T &gt; 1500 K. This UV component likely results from the collisional exchange of energy between CO2(1B) and O2. Limiting further analysis to T &lt; 1500 K, we demonstrate the utility of CO flame band emission by analyzing afterglows at different plasma conditions. We show that the highest energy efficiency for CO production coincides with an operating condition where very little heat has been lost to the environment prior to ∼3 cm downstream, while simultaneously, T ends up below the level required to effectively freeze in CO. This observation demonstrates that, in CO2 plasma conversion, optimizing for energy efficiency does not require a sophisticated downstream cooling method.</p

病院紹介

Background: Delirium is a common condition in hospitalized patients, associated with adverse outcomes such as longer hospital stay, functional decline and higher mortality, as well as higher rates of nursing home placement. Nurses often fail to recognize delirium in hospitalized patients, which might be due to a lack of knowledge of delirium diagnosis and treatment. The objective of the study was to test the effectiveness of an e-learning course on nurses' delirium knowledge, describe nursing staff's baseline knowledge about delirium, and describe demographic factors associated with baseline delirium knowledge and the effectiveness of the e-learning course. Methods: A before-and-after study design, using an e-learning course on delirium. The course was introduced to all nursing staff of internal medicine and surgical wards of 17 Dutch hospitals. Results: 1,196 invitations for the e-learning course were sent to nursing staff, which included nurses, nursing students and healthcare assistants. Test scores on the final knowledge test (mean 87.4, 95% CI 86.7 to 88.2) were significantly higher than those on baseline (mean 79.3, 95% CI 78.5 to 80.1). At baseline, nursing staff had the most difficulty with questions related to the definition of delirium: what are its symptoms, course, consequences and which patients are at risk. The mean score for this category was 74.3 (95% CI 73.1 to 75.5). Conclusions: The e-learning course significantly improved nursing staff's knowledge of delirium in all subgroups of participants and for all question categories. Contrary to other studies, the baseline knowledge assessment showed that, overall, nursing staff was relatively knowledgeable regarding delirium. Trial registration: The Netherlands National Trial Register (NTR). Trial number: NTR 2885, 19 April 2011

Clinical decision rules and measuring renal function in community pharmacy: what do we get out of it?

OBJECTIVE To investigate the frequency and management of drug therapy alerts about drug use in patients with (potential) renal impairment, to investigate the contribution of point-of-care testing (PoCT) of renal function in community pharmacy to the availability of information on renal function, and to investigate pharmacists’ experiences with drug therapy alerts and PoCT. DESIGN AND METHODS A clinical decision support system with clinical decision rules for eleven drugs (seven antibiotics, sotalol, digoxin, allopurinol and spironolactone) and PoCT of renal function were implemented in community pharmacies. The clinical decision rules generated an alert when dose adjustment was advised based on a registered impaired renal function, and when information on the renal function was lacking for patients over 70 years of age with a prescription for one of the selected drugs. Data registered in the clinical decision support system regarding generated alerts, renal functions and alert management were analysed retrospectively. In addition, the participating pharmacists filled out a questionnaire about their experiences. RESULTS 336 pharmacists managed 27.307 alerts for 21.494 patients, leading to 362 dose adjustments and 65 drug replacements. For 16.208 of these patients, renal function has been registered in the clinical decision support system, including over 400 PoCT measurements. Based on PoCT, 25 cases of impaired renal function have been registered, leading to two therapy adjustments. The participating pharmacists were positive about the project. CONCLUSION Advanced clinical decision rules on renal function led to over 400 therapy adjustments. PoCT is a potentially useful source of information on renal function in a limited number of cases, when this information is urgently needed and not available from other sources