摘要： Aldehydes comprise a major portion of skin sensitizers because they can react with both cysteine and lysine. Moreover, cinnamaldehyde (CA) is a typical moderate sensitizer and is often used in an alternative test method for skin sensitization. The amino acid derivative reactivity assay (ADRA) is an in chemico test method that evaluates the reactivity of cysteine derivatives (N-(2-(1-naphthyl)acetyl)-L-cysteine, NAC) and lysine derivatives with the test chemicals and uses CA as a proficiency substance. We found that NAC depletion for CA was only 10-20% when CA was used directly from the reagent bottle, although it increased to almost 100% when stored after being aliquoted from the reagent bottle. It was also found that this was due to the air oxidation of NAC itself rather than the reaction of NAC with CA, indicating that this result simply shows an increase in apparent reactivity. Aldehydes are known to produce active species, such as radicals, during air oxidation. Therefore, we investigated whether radicals were generated under storage conditions using the radical scavenger OH-TEMPO. LC/MS/MS analysis revealed that CA and OH-TEMPO complexes were produced during the air oxidation of CA. In the results of five aldehydes, similar to CA, active species were not generated as significantly as CA. Collectively, during the evaluation of the aldehydes, it can be seen that careful measures need to be taken to prevent the aldehydes from oxidizing during storage, indicating that assessment without preventing air oxidation carries an increased risk of overestimation compared with the intrinsic skin sensitization potency.

关键词： Bayesian inference   credible intervals   equal-tails intervals   highest posterior density intervals   pre-posterior analysis   sample size   skewness  

摘要： In Bayesian inference, the two most widely used methods for set estimation of an unknown one-dimensional parameter are equal-tails and highest posterior density intervals. The resulting estimates may be quite different for specific observed samples but, at least for standard but relevant models, they tend to become closer and closer as the sample size increases. In this article we propose a pre-posterior method for measuring the progressive alignment between these two classes of intervals and discuss relationships with the skewness of the posterior distribution. We illustrate the implementation of the method using the software R for the Poisson model and for some standard examples.

关键词： 木薯   芽前除草剂   芽后除草剂   配用   防草效果  

摘要： 为了探索木薯除草剂较佳的使用方法,进行了木薯芽前除草剂乙草胺与不同芽后除草剂敌草快AS及草胺磷AS配用对比试验。结果表明,每667 m2用200 g 99%乙草胺EC+300 mL敌草快AS配用效果较佳。

关键词： Life cycle assessment   City buses   Air pollutant emissions   Alternative fuels   GREET  

摘要： The road transport sector, particularly public transport, generates significant greenhouse gas emissions due to the excessive use of petroleum-based fuels. The use of alternative fuels with lower environmental impacts is therefore a major challenge to move towards a more sustainable public transport sector. In this context, the current study presents an environmental life cycle assessment of alternative buses, including hybrid (diesel electricity), electric, and fuel cell buses at a city level in Oujda, Morocco. This study is perfromed according to three main outputs: total energy use by fuel type, GHG emissions, and criteria air pollutants. It is concluded that electric and fuel cell buses represent efficient and sustainable alternatives to public transport during the operational phase and their deployment in Oujda city can potentially offer significant environmental savings in terms of GHG emissions and air pollutants during both the WTT and TTW phases. (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

关键词： Transport properties   Diffusion   Lattices   Ions   Defects  

摘要： Although strontium stannate (SrSnO3) has been considered as an anode for Li-ion batteries, a deep understanding of its Li-ion transport properties remains lacking. In this work, the structural, electronic, mechanical, and transport properties of SrSnO3 are explored using density functional theory and force-field-based simulations. Our results show that the norm-conserving approximation is particularly accurate for reproducing the lattice parameters and electronic structure of SrSnO3. SrSnO3 exhibits an indirect energy gap of similar to 3.0 eV, in agreement with the experiment. SrSnO3 is a mechanically stable and a quasi-brittle material that is also more isotropic with respect to the volume change than the shape change. Defect energy simulations reveal a low energetic cost for the Li-ion incorporation mechanism proposed, which is beneficial for its potential application as an electrode material. A comparison of the Li-ion transport properties of Li-doped mono- and nanocrystalline SrSnO3 samples reveals that the nanocrystalline material exhibits a lower diffusion activation energy of similar to 0.28 eV and higher diffusivity at operative temperature. The understanding and properties illustrated in this work open an avenue for the consideration of SrSnO3 as a potential candidate to be used as an anode for Li-ion batteries.

关键词： Multi-physics   Multi-dimensional   SOFC   Alternative mapping   BP neural Network  

摘要： Solid oxide fuel cell (SOFC) stacks have complex multi-physics and multi-dimensional properties that are very difficult to observe in experiments. To solve this problem, a new modeling concept called alternative mapping is introduced in this paper. Using an artificial neural network (ANN), a multi-physics and multi-dimensional stack model can be decomposed into two bonded layers. Both can be solved much more rapidly and robustly than conventional models without losses in accuracy. A SOFC stack model is developed based on this concept. It is calibrated and validated by data from a single cell test and 30-layer stack experiments. The model is robust and rapid. The stack model results show that different physics and dimensional properties are closely related. Changes in each may cause chain reactions in the others, influencing the electrical efficiency or operation ranges. In this report, a fully 3D multi-physics and multi-dimensional dynamic simulation of a SOFC stack is implemented for the first time. Its dynamic behavior is a composite of electric-chemical reactions, gas transport, and heat transfer. These factors vary considerably in different positions and operational conditions.

摘要： Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated with thrombotic complications in adults, but the incidence of COVID-19-related thrombosis in children and adolescents is unclear. Most children with acute COVID-19 have mild disease, but coagulopathy has been associated with multisystem inflammatory syndrome in children (MIS-C), a postinfectious complication. We conducted a multicenter retrospective cohort study to determine the incidence of thrombosis in children hospitalized with COVID-19 or MIS-C and evaluate associated risk factors. We classified patients into 1 of 3 groups for analysis: COVID-19, MIS-C, or asymptomatic SARS-CoV-2. Among a total of 853 admissions (COVID-19, n = 426;MIS-C, n = 138;and asymptomatic SARS-CoV-2, n = 289) in 814 patients, there were 20 patients with thrombotic events (TEs;including 1 stroke). Patients with MIS-C had the highest incidence (9 [6.5%] of 138) vs COVID-19 (9 [2.1%] of 426) or asymptomatic SARS-CoV-2 (2 [0.7%] of 289). In patients with COVID-19 or MIS-C, a majority of TEs (89%) occurred in patients age >= 12 years. Patients age >= 12 years with MIS-C had the highest rate of thrombosis at 19%(9 of 48). Notably, 71% of TEs that were not present on admission occurred despite thromboprophylaxis. Multivariable analysis identified the following as significantly associated with thrombosis: age >= 12 years, cancer, presence of a central venous catheter, and MIS-C. In patients with COVID-19 or MIS-C, hospital mortality was 2.3% (13 of 564), but it was 28% (5 of 18) in patients with TEs. Our findings may help inform pediatric thromboprophylaxis strategies.

关键词： Gas turbine   Molten carbonate fuel cell   Alternative fuels   Energy   Exergy   Efficiency  

摘要： Transportation research is critical in every domain of the transportation sector, including the rail sector. For sustainable rail transportation, alternative/cleaner powering options are badly needed which can only be possible with cleaner fuels. This paper presents a proposed hybrid combined engine system consisting of a gas turbine and a molten carbonate fuel cell combined with an internal combustion engine. The proposed system uses ecofriendly fuels in order to increase the engine performance and reduce carbon emissions. The hybrid combined engine is modeled using Aspen Plus and is thermodynamically analyzed. The alternative fuels chosen for this study are hydrogen, methanol, ethanol, and dimethyl ether. It was found that the proposed powering system can produce 4200 kW, which is doubled the power of the internal combustion engine, with 43% and 55% thermal and exergetic efficiencies, respectively. The cooling load of the absorption refrigeration system varies from 442 kW to 615 kW with maximum energetic and exergetic co-efficient of performances of 18.29% and 9.54%, respectively. The CO2 emissions dropped by more than 60% using alternative fuels. In addition, parametric studies are conducted in the operating pressure of the molten carbonate fuel cell (MCFC) and gas turbine (GT). The best performance can be fulfilled at 200 kPa for the MCFC and 900 kPa for the GT. Therefore, the hybrid combined engine can provide high power with less CO2 emissions and high performance.

关键词： Process simulation   Methanol   Low temperature and pressure   Techno-economic analysis   Cost analysis   CO 2 conversion  

摘要： The novel methanol production from carbon dioxide (CO2) and hydrogen (H2) called alcohol-assisted process is simulated. Although the alcohol-assisted process allows the reduction in operating temperature and pressure, the subsequent product purification is complicated. Comparative studies between the conventional CO2 hydrogenation and the alcohol-assisted processes are carried out (case I-V). The alcohol-assisted processes present the opportunity of increasing the CO2 conversion per-pass and reducing 25% of the hydrogen consumption, the barriers in the conventional process. However, the product purifications remain challenging due to the azeotrope of methanol and by-products. Energy consumptions decrease in the feed and reaction sections of the alcohol-assisted processes but significant increase in the product purifications. The formation of by-products and the sequence of purification units affect process performance and economics. The obtained results indicate that the product purification and the catalyst development to increase methanol selectivity and produce an easy-separated by-product play key roles in the enhancement of the process feasibility. (c) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Superscript/Subscript Available

关键词： C(sp(3))-C(sp(3)) cleavage   cyclobutanes   cyclopropanes   donor-acceptor systems   synthetic electrochemistry  

摘要： We describe the first electrochemical activation of D-A cyclopropanes and D-A cyclobutanes leading after C(sp(3))-C(sp(3)) cleavage to the formation of highly reactive radical cations. This concept is utilized to formally insert molecular oxygen after direct or DDQ-assisted anodic oxidation of the strained carbocycles, delivering beta- and gamma-hydroxy ketones and 1,2-dioxanes electrocatalytically. Furthermore, insights into the mechanism of the oxidative process, obtained experimentally and by additional quantum-chemical calculations are presented. The synthetic potential of the reaction products is demonstrated by diverse derivatizations.