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[Display omitted] • Organic and inorganic sulphur substances led to VSCs in swine manure composting. • COS, CS 2 , MeSH and Me 2 SS were mainly derived from cysteine and methionine. • Me 2 S and EtSH were dominated by the reduction of sulphite and sulphate. • Fe 2 O 3 reduced VSC emission by 46.7–80.9% during composting. • Fe 2 O 3 weakened odour intensity, olfactory value and non-carcinogenic risk of. VSCs. This study aimed to identify the sources of volatile sulphur compounds (VSCs) and evaluate their mitigation by ferric oxide (Fe 2 O 3) during swine manure composting. Four chemicals, including l -cysteine, l -methionine, sodium sulphite, and sodium sulphate, were further added to simulate organic and inorganic sulphur-containing substances in swine manure to track VSC sources during composting. Results show that sulphur simulants induced the emission of six common VSCs, including methyl sulphide (Me 2 S), dimethyl sulphide (Me 2 SS), carbonyl sulphide (COS), carbon disulphide (CS 2), methyl mercaptan (MeSH), and ethyl mercaptan (EtSH), during swine manure composting. Of them, COS, CS 2 , MeSH and Me 2 SS were predominantly contributed by the biodegradation of methionine and cysteine, while Me 2 S and EtSH were dominated by the reduction of sulphite and sulphate. Further Fe 2 O 3 addition at 1.5 % of total wet weight of composting materials immobilized elemental sulphur and inhibited sulphate reduction to reduce the emission of VSCs by 46.7–80.9 %. Furthermore, odour assessment indicated that adding Fe 2 O 3 into composting piles significantly reduced the odour intensity level to below 4, the odour value of VSCs by 47.1–81.3 %, and thus the non-carcinogenic risk by 68.4 %. [ABSTRACT FROM AUTHOR]

Abstract Ignition delay time (IDT) measurements for ethylene (C 2 H 4)/nitrogen dioxide (NO 2)/oxygen/argon mixtures with various blending ratios of NO 2 /C 2 H 4 = 0/100, 15/85 and 50/50 were performed in a shock tube. The sensitization effect of NO 2 on C 2 H 4 ignition was investigated at pressures ranging from 1.2 to 10 atm, in the temperature range 920–1780 K, and at equivalence ratios from 0.5 to 2.0. Similar to our recent studies of NO 2 effects on CH 4 and C 2 H 6 ignition (Deng et al., 2016; Deng et al., 2017), the effect of NO 2 addition on measured IDTs of the unsaturated hydrocarbon C 2 H 4 also exhibits both temperature- and pressure- dependences. NO 2 addition generally promotes the reactivity of ethylene and the promotion effect is more pronounced for the mixtures with high NO 2 content at higher pressures (p > 4.0 atm), at lower temperatures (T < 1200 K) and for fuel-rich mixtures. However, NO 2 shows only a limited effect at lower pressures (p < 4.0 atm) and at higher temperatures (T > 1250 K). A detailed kinetic mechanism of C 2 H 4 /NO 2 was proposed by refining critical reactions through incorporating ab-initio calculations from this study and recently published rate constant data. This mechanism is capable of reproducing the new data reported in this work and literature ones as well and has thus been used to perform sensitivity and flux analyses to kinetically interpret the interaction of NO 2 with C 2 H 4. [ABSTRACT FROM AUTHOR]

Abstract H-atom abstraction and addition are the two most important reactions in alkene oxidation. As a complement of our synchronization work of 3-hexene chemistry (Feiyu Yang et al., Kinetics of Hydrogen Abstraction and Addition Reactions of 3-Hexene by ȮH Radicals, J. Phys. Chem. A 2017, 121, 1877–1889), high-accuracy electronic structure calculations (DLPNO CCSD(T)/CBS) and canonical variational transition state theory are used to predict the rate coefficients of the H-atom abstraction and addition reactions of 3-hexene + ĊH 3 /Ḣ/Ö system. Although ĊH 3 /Ḣ/Ö are all nonpolar radicals, Ḣ + 3-hexene system shows some unique features. Unlike the 3-hexene + ĊH 3 /Ö systems, the potential energy surface of 3-hexene + Ḣ system exhibits a unique "negative well" characteristic, suggesting the energy of the well is higher than its corresponding reactant or product. Analysis shows that the "negative well" characteristic is caused by the relative larger zero-point energies of Van der Waals complex of H + 3-hexene system. Moreover, the evolution of adiabatic ground-state energy shows wells/well-like curves at both reactant and product sides for 3-hexene + ĊH 3 and Ö systems, but only at reactant end for 3-hexene + Ḣ system. Vibrational analysis reveals that for 3-hexene + ĊH 3 and Ö systems, the wells/well-like curves are generated by the C = C double bond stretch motion, while it is generated by the forming H H single bond stretch motion for 3-hexene + Ḣ system. Branching ratio shows that addition and abstraction dominate at low and high temperatures and the critical temperatures are 478 K, 794 K and 735 K for 3-hexene + ĊH 3 , Ḣ and Ö systems, respectively. Rate coefficients with a conservative uncertainty of a factor of 5 are estimated based on similar algorithm of Sun and Law. In addition, analyses on the potential energy surface, minimum energy path, adiabatic ground-state energy and activation free Gibbs energy change are also performed in this work. [ABSTRACT FROM AUTHOR]

• A lipid-lowering active rapeseed peptide was obtained from rapeseed meal. • Evaluated the lipid-lowering activity of rapeseed peptides. • Clarified the mechanism of rapeseed peptide's lipid-lowering effect. Hyperlipidaemia, a common chronic disease, is the cause of cardiovascular diseases such as myocardial infarction and atherosclerosis. Generally, drugs for lowering blood lipids have disadvantages such as short or poor efficacy, high toxicity, and side effects. Rapeseed active peptides are excellent substitutes for lipid-lowering drugs because of their high biological safety, strong penetration, and easy absorption by the human body. This study separated and purified the rapeseed peptides using gel chromatography and mass spectrometry. Rapeseed peptides amino acid sequences were determined to obtain Glu-Phe-Leu-Glu-Leu-Leu (EFLELL) peptides with good hypolipidaemic activity and IC 50 values of 0.1973 ± 0.05 mM (sodium taurocholate), 0.375 ± 0.03 mM (sodium cholate), and 0.203 ± 0.06 mM (sodium glycine cholate). The EFLELL hypolipidaemic activity was evaluated, and its mechanism of action was investigated using cell lines. Rapeseed peptide treatment significantly decreased the total cholesterol (T -CHO), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) levels, and the protein and gene expression levels of proprotein convertase subtilisin/kexin type 9 (PCSK9) and low-density lipoprotein cholesterol (LDLR) suggested the mechanism. Molecular docking revealed that the binding energy between rapeseed peptide and LDLR-PCSK9 molecules was −6.3 kcal/mol and −8.1 kcal/mol. In conclusion, the rapeseed peptide EFLELL exerts a favourable hypolipidaemic effect by modulating the LDLR-PCSK9 signalling pathway. [ABSTRACT FROM AUTHOR]

[Display omitted] • A machine learning tool solve the single-track rail scheduling problem is proposed. • On a gridworld model, optimal solutions are obtained under constraint application. • The algorithm uses deep convolutional neural networks to process image-like input information. This study proposes a deep reinforcement learning approach for bi-direction single-track railway scheduling called DRLA-eTGM. The goal is to define the departure times and track allocation without conflict for all trains on the line given their speed, priority, origin, and destination while minimizing the total priority-weighted dwelling time. A novel time–space-capacity gridworld model (TGM), which contains a two-dimensional state representation to dynamically describe the distribution of constraints and trains in single-track railway scheduling, is proposed. Moreover, DRLA-eTGM innovatively extracts and exploits features from the TGM state automatically with deep convolutional neural networks to enhance scheduling decision strategies. Further, a shaping technique inspired by dynamic programming is adopted in DRLA-eTGM. Computational experiments are presented to verify the effectiveness of the proposed approach using hypothesized instances and a busy passenger-cargo single-track railway corridor in China. The experimental results show that DRLA-eTGM outperforms some heuristic and reinforcement learning algorithms, especially in real-world instances. Compared to some deep reinforcement learning algorithms, DRLA-eTGM shows robustness and efficiency owing to its partial scalable observation and parameter sharing mechanisms. This study provides a new approach to exploiting constraint information in railway scheduling and a prototype system for automatic single-track railway scheduling. [ABSTRACT FROM AUTHOR]

The ground-state potential energy surface (PES) of isomerization philosophy of ten normal-chain hexadiene isomers is computed by density functional methods using the geometries optimized at B3LYP/6-311++G (d, p) level of theory. These detailed reaction pathways are used to calculate the rate constants for the unimolecular isomerization reactions by transition state theory (TST) in the temperature range of 500–2500 K. Difference of rate constant between each hexadiene isomer is interpreted through the PES and Ḣ atom transfer, and only 2,4-hexadiene readily fulfills cis - cis to trans-trans conformation conversion. All the conversions are kinetically interpreted from the PES and ST geometry. [ABSTRACT FROM AUTHOR]

Nitrogen dioxide (NO 2 ) is an important impurity in coal-bed methane (CBM) and a dominant component of NO x pollution in practical engines. Its promoting effect on methane ignition has been studied in the current experimental and kinetic study. Ignition delay times of NO 2 /CH 4 /O 2 /Ar mixtures, with blending ratios of NO 2 :CH 4 of 30:70, 50:50 and 70:30 for stoichiometric methane mixtures were measured in a shock tube. Experiments cover a range of pressures (1.2–10.0 atm) and temperatures (933–1961 K). Under all tested pressures, NO 2 addition promotes the reactivity of methane and reduces the global activation energy at all pressures, and these effects are most significant for the mixtures with highest NO 2 concentrations, at the highest pressures and at the lowest temperatures. To simulate the experimental measurements, five literature NO x sub-mechanisms were integrated with AramcoMech 1.3. The simulations demonstrate that, for the mixtures with low levels of NO x concentrations, the five models agree well with the experimental ignition delay times. For the mixtures with high NO x content, however, all five models are unable to reproduce the measured data, and the level of disagreement increases with increasing NO 2 concentration. An updated mechanism is proposed, based on modifications made as a result of sensitivity and reaction flux analyses performed to quantitatively determine the chemical reasons for NO 2 promoting methane ignition. The results indicate that, NO 2 addition perturbs the branching ratio of key reaction pathways by affecting the structure of the free radical pool at the initial ignition stage of methane oxidation. A new reaction cycle via the following sequence of reactions ĊH 3 + NO 2 ⇔ CH 3 O ̇ + NO, CH 3 O ̇ + M ⇔ CH 2 O + Ḣ + M, NO 2 + Ḣ ⇔ NO + O ̇ H, and CH 4 + O ̇ H ⇔ ĊH 3 + H 2 O is proposed to explain the observed effect of NO 2 addition on the promotion of methane ignition. [ABSTRACT FROM AUTHOR]

Abstract: Densified ZrB2–SiC-based ultra-high temperature ceramics reinforced with short carbon fibers were prepared by conventional hot-pressing. The microstructure, mechanical and oxidation resistance properties of the composite were investigated. The Csf/ZrB2–SiC composite had improved fracture toughness of 6.6MPam1/2 compared to ZrB2–SiC composite of 4.3MPam1/2 due to fiber debonding, fiber pull-out and fiber bridging as well as crack deflection. It was found that the low modulus of carbon fiber and a graphitization transition layer between fiber and matrix led to the decreased flexural strength. The oxidation resistance tests were carried out on Csf/ZrB2–SiC using an oxyacetylene torch. The temperature of the oxidized specimen exceeded 1800°C and the surface layer appeared dense and adherent. No macro-cracks or spallation were detected, suggesting that these composites possess a better oxidation resistance than ZrB2–SiC. The improved oxidation resistance is attributed to the formation of a coherent SiO2 rich scale, which acts as an effective barrier against the inward diffusion of oxygen. The results presented here point to a potential way for improving toughness of composite without sacrificing oxidation protection. [Copyright &y& Elsevier]

Abstract: The major problems associated with zirconium diboride-based ceramics are lack of damage tolerance as structure components, so ZrB2/20vol% SiC based ceramics toughened by 20vol% short carbon fibers were produced by hot pressing at 2000°C under 30MPa for 1h. SEM results showed that short carbon fibers could disperse uniformly in powder mixtures and sintered sample through milling. Three-point bend strength and fracture toughness were measured. The decrease in strength from 448MPa to 397MPa as the addition of short fibers was attributed to the chemical reaction between fiber and matrix. The fracture toughness increased from 4.25MPam1/2 for ZrB2/SiC to 6.35MPam1/2 for short fibers toughened ZrB2/SiC, which was led by the crack deflection and fiber fracture. [Copyright &y& Elsevier]

Abstract: A ZrB2–20 vol.% SiC based ceramic matrix composite containing 20 vol.% short carbon fibers was top pressed at 2000 °C and 30 MPa for 1 h. The microstructure and mechanical properties of the composite were investigated. The fracture toughness was 6.56 MPa·m1/2, which is 54% higher than that of ZrB2–20 vol.% SiC composite. The toughening mechanisms were fiber debonding, fiber pull-out and crack deflection. Moreover, it was found that a graphitization transition layer between fiber and matrix led to the decreased in flexural strength. The results presented here point to a potential way for improving the fracture toughness of ultra-high temperature ceramics. [Copyright &y& Elsevier]

The rate coefficients of H abstraction and OH addition reactions of 2,4,4-trimethyl-1-pentene with OH were determined by both canonical variational transition state theory and conventional transition state theory. The potential energy surfaces were calculated at CCSD(T)/6-311++G(d, p)//BHANDHLYP/6-311(d, p) level and quantum effects were evaluated by the one-dimensional Wigner method and the multidimensional zero-curvature and small-curvature tunneling methods. 2,4,4-Trimethyl-1-pentene contains primary and secondary allylic H abstraction, alkyl, and vinylic H abstraction channels and OH addition into central and terminal carbon atoms channels. The results show that allylic H abstraction channels dominate the overall H abstractions resulting from the lower barriers, in which, primary H abstraction involves indirect channel via a reactant complex and direct channel. Moreover, OH addition reactions into central and terminal carbon atoms all contain Van der Waals reactant complexes, while the latter channel exhibits negative temperature dependence as a result of its submerged barrier. The branching ratio is more than 75% for addition reactions below 500 K and more than 80% above 1100 K for H abstraction reactions. Rate coefficients of all channels were fitted in terms of a quasi-Arrhenius expression. [ABSTRACT FROM AUTHOR]

Ignition delay times were measured behind reflect shock waves for the lean DME/ n -pentane fuel blends with DME blending ratios from 0% to 100% over a wide range of conditions: pressures from 2 to 20 atm, temperatures from 1100 to 1600 K and equivalence ratio of 0.5. Correlations of ignition delay times of DME/ n -pentane were deduced from the experimental data using multiple linear regression. Comparison between measured ignition delay times and numerical predictions by five available kinetic mechanisms, namely NUI Galway pentane isomer model, JetSurF2.0 model, LLNL n -alkanes Model, NUI Galway Mech_56.54 Model and Wang’s DME model, were conducted. NUI Galway pentane isomer model shows good predictions for ignition delay times of DME, n -pentane and their blends which was conducted in this study to interpret the effect of DME addition on the ignition chemistry of n -pentane. [ABSTRACT FROM AUTHOR]

• DGE method detects forest disturbances with GMM and EM. • DGE outperforms traditional methods like ANAC, PGC, BL, and AI. • Broad DGE applications in disturbances, growth-climate relationship and other ecology fields. Forests have experienced unprecedented decline and mortality beyond their historical range in past decades, which is attributed to disturbances like drought, fire, insects and disease. Traditional disturbance detection methods that typically employ a time series perspective to identify discrete disturbance events within continuous tree growth signals and were mainly designed for gap-scale often fail to identify disturbances across populations. To more accurately identify growth suppression and release clusters based on the perspective of forest population dynamics, here we applied a novel method of detecting forest disturbances using a Gaussian mixture model with an expectation maximisation algorithm (DGE), to fit annual distributions of growth indicators, i.e., tree-ring index. We further compared our novel approach of DGE with five traditional methods based on two sets of real tree-ring data and simulated tree-ring data. The results show an improvement of accuracy (35.5 %–48.1 %), sensitivity (36.6 %–58.1 %), precision (21.2 %–51.5 %) and specificity (11.1 %–20.6 %) for the average of two real radial growth datasets and an improvement of accuracy (7.6 %–13.9 %), sensitivity (70 %), precision (100 %) and specificity (9.1 %–9.7 %) for the simulation radial growth dataset, indicating that our DGE approach performs much better than the traditional methods. This study contributes to an improved strategy and understanding for sustainable forest management in the context of climate warming, demonstrating that our DGE approach can be better applied to global forest disturbance detection under global change. [ABSTRACT FROM AUTHOR]

The road ice is a common phenomenon, which brings a safety risk to traffic. Carbon nanotube is an excellent photothermal conversion material. In outdoor environment, carbon nanotube can convert solar energy into heat energy to achieve the purpose of melting ice. In this paper, an emulsified asphalt coating modified by carbon nanotubes (CNTs) and polytetrafluoroethylene (PTFE) was prepared. During the preparation, we found that the optimal ratio of PTFE and CNTs is 1:1, and the optimal spraying amount is 400 ml/m2. The photothermal conversion performance test shows that the freezing time of water on the coating surface is significantly prolonged under near-infrared light irradiation. With the increase of light intensity, icing does not appear on coated surfaces. At the same time, the melting time of ice on the coating surface is about twice shorter than that on the unmodified asphalt surface under near-infrared irradiation. The superhydrophobic performance test shows that the contact angle of droplets on the coating surface can reach more than 150°, and the adhesion strength of ice on the coating surface is greatly reduced. The microscopic morphology of the coating shows that CNTs and PTFE are evenly distributed on the surface of the coating. To sum up, the photothermal hydrophobic coating has a good application potential for road anti-icing and de-icing. • CNTs/PTFE modified emulsified asphalt coating has superhydrophobicity. • The temperature of CNTs/PTFE modified emulsified asphalt coating increases by 13.4 ℃ under light irradiation. • CNTs/PTFE modified emulsified asphalt coating significantly prolongs the freezing time. • CNTs/PTFE modified emulsified asphalt coating has good durability and road performance. [ABSTRACT FROM AUTHOR]

The reaction kinetics of alkenes + hydroperoxyl (HȮ 2) system is of importance to low/intermediate temperature chemistry of alkanes. This work is a follow up of our previous study on 3-hexene + ȮH 1 ,. The rate coefficients were determined using the canonical variational transition-state theory. Results revealed that the asymmetric geometry of the HȮ 2 radical generated numerous reaction sub-channels. The rate coefficients, with a conservative uncertainty (factor of 5), were obtained to develop the detailed chemical mechanism of 3-hexene. Additionally, potential energy surface, minimum reaction path, adiabatic ground-state energy, and activation free Gibbs energy change (ΔG) calculations were also performed. [ABSTRACT FROM AUTHOR]

The color rendering index (CRI) and Commission Internationale de L'Eclairage coordinate (CIE x,y) are significant parameters for the white organic light-emitting diodes (WOLEDs). We fabricate a series of the phosphorescent WOLED devices, in which there are two doped phosphorescent layers (for blue emission) on both sides of the emitting layer (EML) and three ultrathin phosphorescent layers (for red, orange and green emission) separated by the spacer layers (mCP) in EML. One doped blue emission layer near the hole transport layer contributes to CRI enhancement by increasing the doping concentration (x %) of the blue phosphorescent dye because Dexter energy transfer increases from the blue emission to the red emission. When x is 20, CRI reaches to 90 at 5 V in device A3. Based on device A3, CRI can be further improved to 94 in device B1 with a thinner thickness of the spacer layer (y = 1 nm) between the green emission layer and orange emission layer in EML because Dexter energy transfer from the green emission layer to the orange and red emission layer becomes easier. Although CRI declines, the spectra become more stable by increasing the thickness of the spacer layer (y = 3 nm) in device B2 or decreasing the thickness of the green emission layer (z = 0.05 nm) in device C, in which the CIE x,y coordinate shift is only (0.0214, 0.0102) from 5 V to 8 V. Image 103750 • The double doped blue phosphorescent layers (EML1 and EML5) on both sides of EML can adjust CRI and spectra stability. • The EML1 near HTL is beneficial for CRI and the red emission by increasing the doping concentration of FIrpic. • The EML5 near ETL can improve spectra stability by increasing the thickness of the spacer layer (Spacer2). • The EML5 near ETL can improve CRI by decreasing the thickness of green ultrathin phosphorescence layer (EML4). [ABSTRACT FROM AUTHOR]

Nitrogen dioxide (NO 2 ) is a dominant component of NOx pollution in combustion of internal combustion engines and gas turbines. Its sensitization on ignition of ethane which is a main component of natural gas has been investigated in this experimental and kinetic study. Ignition delay times of NO 2 /C 2 H 6 /O 2 /Ar mixtures, with blending ratios of NO 2 :C 2 H 6 of 0.3:1 and 1:1, were measured in a shock tube. Experimental conditions cover a range of pressures (1.2–20 atm), temperatures (950–1700 K) and equivalence ratios (0.5–2.0). Similarly to our previous work of CH 4 /NO 2 (Deng et al., 2016) [14], NO 2 addition promotes the reactivity of ethane and reduces the global activation energy particularly at higher pressures ( p > 5.0 atm) and lower temperatures ( T < 1175 K), whereas it only presents a limited effect at low pressure (1.0 atm) and higher temperatures ( T > 1175 K). Furthermore, an opposite effect of NO 2 addition is observed in both the experiments and the simulations at different temperature regimes. Compared to fuel-rich mixture, NO 2 addition exhibits more significantly promoting effect on the ignition of fuel-lean mixture under given NO 2 concentration. Four literature kinetic mechanisms and an updated mechanism proposed in this study have been compared to simulate the new ignition delay time data and the literature data. Overall, the proposed model is capable of reproducing the experimental results measured by various facilities over a wide range of conditions. The proposed model is thus used to carry out the sensitivity and flux analyses to clarify the chemistry interaction between NO 2 and ethane. Based on the kinetic analyses, the impact of NO 2 has been expounded at different conditions. [ABSTRACT FROM AUTHOR]

Ignition delay times of 1-pentene and n -pentane were measured using a shock tube at pressures from 0.12 MPa to 1.0 MPa, at equivalence ratios from 0.5 to 2.0 with 0.5% and 1.0% fuel concentrations, in the temperature range of 1040–1880 K. Correlations of 1-pentene and n -pentane ignition delay times were deduced from the experimental data using a multiple linear regression. A NG model, JetSurF2.0 model and Touchard model were used to simulate the experiments but the performance was not good for all data. The C1–C4 sub-model of the NG model was updated using Aramco Mech 1.3, forming the Aramco-NG model, which conformed closely to the experiments. A crossover of the ignition delay times of 1-pentene and n -pentane can be observed in the correlations and calculations as well as in the experimental data. The shorter ignition delay times of 1-pentene in the relative low temperature region can be explained by the abundant H atom producing channels and the higher rate constant of the unimolecular decomposition reaction in this region. In the relative high temperature region, the higher amount of allyl radical formed through the breakage of the C γ C δ bond and lower concentration of oxygen may contribute to the longer ignition delay times for 1-pentene compared with n -pentane. [ABSTRACT FROM AUTHOR]