Mécanisme de la réduction electrochimique en milieu non aqueux de materiaux cathodiques utilisés dans les piles au lithium,III. Réduction électrochimique d'électrodes membranaires de sulfures et oxydes de cuivre dans le mélange carbonate de propylène-1,2-diméthoxyéthane

Résumé L'étude de la réduction électrochimique d'électrodes membranaires de CuS et de CuO dans le mélange de solvant constitué par 20% en volume de carbonate de propylène et 80% de 1, 2-diméthoxyéthane, nous a conduits à admettre un mécanisme de réduction par insertion progressive d'électrons et d'ions Li⁺ dans le réseau cristallin de ces deux matériaux. En ce qui concerne CuS, cette insertion correspond à la réaction élémentaire en phase solide CuS+xe+xLi⁺ CuSLi _x . L'espèce formée à l'issue de cette réaction évoluerait alors soit vers la formation de Cu₂S dans le cas des faibles régimes de décharge, soit directement vers la formation de cuivre dans le cas des forts régimes de décharge. En ce qui concerne CuO, cette insertion correspondrait à la réaction CuO+xe+xLi⁺ CuOLi _x mais dans ce cas la formation de Cu₂O ne serait jamais possible, l'espèce intermédiaire formée évoluerait directement vers la formation de cuivre quels que soient les régimes de décharge.

---

The study of the electrochemical reduction of CuS and CuO membrane electrodes in 20 vol% propylene carbonate/80 vol% 1, 2-dimethoxyethane shows that the reaction proceeds via insertion of electrons and lithium ions into the crystalline lattice of the two materials. In the case of CuS, the overall reaction in the solid phase is CuS+2e+xLi⁺ CuSLi _x . At low discharge rates Cu₂S is formed but at high rates of discharge the reaction proceeds through to Cu metal. With CuO the reaction is CuO+xe+xLi⁺ CuOLi _x but the formation of Cu₂O never occurs; the reaction goes to Cu under all discharge conditions.

     

Photocatalytic degradation of a phenylurea, chlortoluron, in water using an industrial titanium dioxide coated media

The degradation of an herbicide, chlortoluron, by UV/TiO₂ photocatalysis in water using industrial titanium dioxide coated non-woven paper was studied. The influence of parameters such as adsorption capacity, initial concentration and TiO₂ implementation (coated or in suspension) was investigated. The results emphasize the importance of operational conditions and reactor geometry on the kinetic degradation rate. The analysis of the first organic by-products suggests that a hydroxyl radical attack occurs on the phenyl ring and methyl groups of the chlortoluron before the opening of the aromatic ring. The fate of hetero-atoms has been investigated. The fates of the two nitrogen atoms in the molecule are different, not only did it depend on their initial oxidation degree, as both had the same oxidation degree, but also on the initial oxidation state of neighboring carbons. The chlorine atoms were completely released as chloride ions. The study of the influence of the oxygen concentration showed the importance of the oxygen mass transfer when designing an industrial photocatalytic reactor. An original calculation process was carried out to evaluate the adsorption constant of oxygen over the whole photocatalysis period and not only in the initial conditions as previously provided. This work points out the necessity of extending the understanding of the efficiency of chlortoluron removal or of the removal of various complex pesticide mixtures found in agricultural wastewater, using alternative, more industrially realistic, reactors.     

The effects of pick density on order picking areas with narrow aisles

The cost and service performance of an order fulfillment center are determined partly by how workers are organized into an order picking system. One common approach is batch picking, in which workers circumnavigate a picking area with other workers, gathering items on a pick list. In some systems with high space utilization, narrow aisles prohibit workers from passing one another when in the same aisle, and this leads to congestion. We build analytical and simulation models of these systems to investigate their behavior under different levels of activity. Among other things, our results suggest that when the system is busier and pick density is high (that is, when workers stop often to make picks) congestion is less of a problem and workers are more productive.     

Performance of Alcohol and Safer Sex Change Rulers Compared With Readiness to Change Questionnaires.

As part of a larger intervention study, the authors hypothesized that change rulers created for alcohol and safer sex would be equivalent to longer questionnaires. Ninety-six male college students completed rulers and questionnaires for assessing behavior change readiness. Participants' scores on the rulers significantly correlated with their scores on the questionnaires (r = .77 for alcohol; r = .77 for safer sex). In both domains, the rulers outperformed the questionnaires in predicting behavioral intentions, suggesting that the rulers had at least comparable concurrent criterion validity. This finding is the first of its kind in the safe sex literature and suggests that quick assessments of readiness to change are possible. Because the rulers are a continuous measure, the results are consistent with the idea that the change process is continuous rather than a series of discrete stages. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reasoning about Knowledge: A Response by the Authors

Minds and Machines -     

Numerical inversion of multidimensional Laplace transforms by the Laguerre method

Numerical transform inversion can be useful to solve stochastic models arising in the performance evaluation of telecommunications and computer systems. We contribute to this technique in this paper by extending our recently developed variant of the Laguerre method for numerically inverting Laplace transforms to multidimensional Laplace transforms. An important application of multidimensional inversion is to calculate time-dependent performance measures of stochastic systems. Key features of our new algorithm are: (1) an efficient FFT-based extension of our previously developed variant of the Fourierseries method to calculate the coefficients of the multidimensional Laguerre generating function, and (2) systematic methods for scaling to accelerate convergence of infinite series, using Wynn's ε-algorithm and exploiting geometric decay rates of Laguerre coefficients. These features greatly speed up the algorithm while controlling errors. We illustrate the effectiveness of our algorithm through numerical examples. For many problems, hundreds of function evaluations can be computed in just a few seconds.     

Analysis of some paper handling problems by a three-dimensional nonlinear finite element algorithm

A three-dimensional nonlinear finite element algorithm was developed to predict the change in paper topology as well as the wrinkle performance of the roll feeding systems. The initial shape of the thin plate to be analyzed can be perfectly flat or wavy. The roll system can be of any arbitrary configuration with manufacturing tolerance included. The algorithm described here uses the total Lagrange formulation with Piola-Kirchhoff stress and Green-Lagrange strain. Gap elements are used to simulate the physical significance of the paper supports. Quasistatic solutions at different time intervals are calculated. The change in topology and the locations of predicted wrinkles are found to agree with experiments.     

A Comparision of Starch Granules as Seen by Both Scanning Electron and Ordinary Light Microscopy

Starch being a transparent crystal often give images which are difficult to precisely define with the light microscope due to the diffraction and other effects such as internal structure which may appear as a surface phenomena. The scanning electron microscope (SEM); however, gives only surface detail. In a effort to differentiate between surface and internal details, the same starch granules have been studied by both ordinary light and scanning electron microscopy. In each case the granules were held in the same configuration as was seen with the light microscope when they were studied by SEM. In this way a direct comparison could be made between granules viewed by each microscopy technique. From such comparisons it is possible to determine the starch details that are actually due to internal features. The results for canna, potato and corn starches are given.     

Development of a Mortality Prediction Model in Hospitalised SARS-CoV-2 Positive Patients Based on Routine Kidney Biomarkers

Acute kidney injury (AKI) is a prevalent complication in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive inpatients, which is linked to an increased mortality rate compared to patients without AKI. Here we analysed the difference in kidney blood biomarkers in SARS-CoV-2 positive patients with non-fatal or fatal outcome, in order to develop a mortality prediction model for hospitalised SARS-CoV-2 positive patients. A retrospective cohort study including data from suspected SARS-CoV-2 positive patients admitted to a large National Health Service (NHS) Foundation Trust hospital in the Yorkshire and Humber regions, United Kingdom, between 1 March 2020 and 30 August 2020. Hospitalised adult patients (aged ≥ 18 years) with at least one confirmed positive RT-PCR test for SARS-CoV-2 and blood tests of kidney biomarkers within 36 h of the RT-PCR test were included. The main outcome measure was 90-day in-hospital mortality in SARS-CoV-2 infected patients. The logistic regression and random forest (RF) models incorporated six predictors including three routine kidney function tests (sodium, urea; creatinine only in RF), along with age, sex, and ethnicity. The mortality prediction performance of the logistic regression model achieved an area under receiver operating characteristic (AUROC) curve of 0.772 in the test dataset (95% CI: 0.694–0.823), while the RF model attained the AUROC of 0.820 in the same test cohort (95% CI: 0.740–0.870). The resulting validated prediction model is the first to focus on kidney biomarkers specifically on in-hospital mortality over a 90-day period.