Cyclic Ketones as Future Fuels: Reactivity with OH Radicals

For a sustainable energy future, research directions should orient toward exploring new fuels suitable for future advanced combustion engines to achieve better engine efficiency and significantly less harmful emissions. Cyclic ketones, among bio-derived fuels, are of significant interest to the combustion community for several reasons. As they possess high resistance to autoignition characteristics, they can potentially be attractive for fuel blending applications to increase engine efficiency and also to mitigate harmful emissions. Despite their importance, very few studies are rendered in understanding of the chemical kinetic behavior of cyclic ketones under engine-relevant conditions. In this work, we have conducted an experimental investigation for the reaction kinetics of OH radicals with cyclopentanone and cyclohexanone for the first time over a wide range of experimental conditions (T = 900–1330 K and p ≈ 1.2 bar) in a shock tube. Reaction kinetics was followed by monitoring UV laser absorption of OH radicals near 306.7 nm. Our measured rate coefficients, with an overall uncertainty (2σ) of ±20%, can be expressed in Arrhenius form as (in units of cm3 molecule–1 s–1): k1(CPO+OH)=1.20×10−10exp(−2115KT) (902–1297 K); k2(CHO+OH)=2.11×10−10exp(−2268KT) (935–1331 K). Combining our measured data with the single low-temperature literature data, the following three-parameter Arrhenius expressions (in units of cm3 molecule–1 s–1) are obtained over a wider temperature range: k1(CPO + OH) = 1.07×10−13(T300K)3.20exp(1005.7KT) (298–1297 K); k2(CHO+OH)=3.12×10−13(T300K)2.78exp(897.5KT) (298–1331 K). Discrepancies between the theoretical and current experimental results are observed. Earlier theoretical works are found to overpredict our measured rate coefficients. Interestingly, these cyclic ketones exhibit similar reactivity behavior to that of their linear ketone counterparts over the experimental conditions of this work

Fe₃O₄@SiO₂@TiO₂@Pt Hierarchical Core–Shell Microspheres: Controlled Synthesis, Enhanced Degradation System, and Rapid Magnetic Separation to Recycle

Magnetic composite microspheres consisting of a SiO₂-coated Fe₃O₄ core, an ordered TiO₂ hierarchically structured shell, and a Pt nanoparticle layer dispersed on the surface of the TiO₂ nanoplatelets have been successfully synthesized using a facile and efficient method. The shells of TiO₂ hierarchical microspheres were assembled from nanoplatelets, which exposed the high-energy {001} facets, and the Pt nanoparticles were evenly deposited on the surface of the TiO₂ nanoplatelets, with a concentration of ∼1 wt %. The resulting composite microspheres exhibited flower-like hierarchical structures with a 202.42 m² g^–1 surface area and possessed superparamagnetic properties with a high saturation magnetization of 31.5 emu g^–1. These features endow the obtained composite microspheres with a high adsorption capacity and strong magnetic responsivity that could be easily separated by an external magnetic field. The high photocatalytic activity toward Rhodamine B (RhB) degradation may be caused by the hierarchically structured TiO₂ with exposed high-energy {001} facets and the Pt nanoparticle deposits on TiO₂ surfaces, which would be efficient for the electron transfer reactions. In addition, the composite microspheres showed high recycling efficiency and stability over several separation cycles

Symmetric Ethers as Bioderived Fuels: Reactivity with OH Radicals

Environmental pollution and greenhouse gas emissions are major challenges faced by our society. One possible way to mitigate global warming is to cut CO2 emissions by taking a shift from conventional fuels to renewable fuels for future sustainability. Carbon neutral fuels produced in a sustainable carbon cycle can close the carbon cycle and reach net zero-carbon emission. To this end, ethers are promising renewable fuels and/or additives for future advanced combustion engines. Therefore, understanding the oxidation behavior of ethers under engine-relevant conditions is of utmost importance. In this work, the reaction kinetics of hydroxyl radicals with dimethyl ether (DME), diethyl ether (DEE), di-n-propyl ether (DPE), and di-n-butyl ether (DBE) were investigated behind reflected shock waves over the temperature range of 865–1381 K and the pressure range of 0.96–5.56 bar using a shock tube and a UV laser diagnostic technique. Hydroxyl radicals were monitored near 306.7 nm to follow the reaction kinetics. These reactions did not exhibit discernible pressure effects. The temperature dependence of the measured rate coefficients can be expressed by the following modified Arrhenius equations in units of cm3 mol–1 s–1: k1(DME+OH) = 1.19 × 1014 exp­(−2469.8/T), k2(DEE+OH) = 1.27 × 107T2 exp­(327.8/T), k3(DPE+OH) = 1.64 × 107T2 exp­(368.4/T), k4(DBE+OH) = 9.12 × 1011T0.65 exp­(−843.5/T). Our measured rate data were analyzed to obtain site-specific rates and branching ratios. Our results are compared with the available literature data wherever applicable. Furthermore, the ability of Atkinson’s structure–activity relationship (SAR) to predict the kinetic behavior of the reactions of dialkyl ethers with OH radicals was examined

Pt@CeO₂ Multicore@Shell Self-Assembled Nanospheres: Clean Synthesis, Structure Optimization, and Catalytic Applications

A clean nonorganic synthetic method has been developed to fabricate the uniform pomegranate-like Pt@CeO₂ multicore@shell nanospheres in a large scale. Under the effective protection of Ar atmosphere the redox reaction just simply happened between Ce­(NO₃)₃ and K₂PtCl₄ in an alkaline aqueous solution, in which no other reducing agents or surfactants were added. The as-obtained nanospheres exhibited excellent structure stability even being calcined at 600 °C for 5 h. Moreover, the as-obtained Pt@CeO₂ multicore@shell nanospheres can be further supported on reduced graphene oxide (RGO) to form heterogeneous nanocatalyst, which has been successfully applied in the chemical reduction reaction of nitrophenol (NP) by ammonia borane (NH₃BH₃, dubbed as AB) instead of hazardous H₂ or NaBH₄

Schematic illustration of pressure balance system in 81107 working face.

Schematic illustration of pressure balance system in 81107 working face.</p

FAM83A-AS1 promotes lung adenocarcinoma cell migration and invasion by targeting miR-150-5p and modifying MMP14

Accumulating evidence has indicated that long noncoding RNAs (lncRNAs) play pivotal roles in the processes of cancer occurrence, progression, and treatment. FAM83A-AS1 is a novel onco-lncRNA involved in various cancers. Nevertheless, the biological function and underlying mechanism of FAM83A-AS1 in lung adenocarcinoma (LUAD) remain largely unclear. In this study, we found FAM83A-AS1 to be upregulated in LUAD tissues and closely associated with tumor size, lymph node metastasis, and TNM stage. In addition, high FAM83A-AS1 expression correlated positively with a poor prognosis. Functional investigation revealed that FAM83A-AS1 promotes LUAD cell proliferation, migration, invasion and the epithelial-mesenchymal transition (EMT) in vitro and tumor growth in vivo. Mechanistically, FAM83A-AS1 functions as an endogenous sponge of miR-150-5p by directly targeting it, removing inhibition of MMP14, a target of miR-150-5p. Furthermore, rescue assays demonstrated that FAM83A-AS1 enhances cell migration, invasion and EMT by modulating the miR-150-5p/MMP14 pathway. Collectively, we conclude that the novel FAM83A-AS1/miR-150-5p/MMP14 axis regulates LUAD progression, suggesting an innovative therapeutic strategy for this cancer.</p

Schematic illustration of air leakage passages connecting ground, 12# coal seam and 81107 working face.

Schematic illustration of air leakage passages connecting ground, 12# coal seam and 81107 working face.</p

Parameters of the gas in the 81105 gob borehole prior to and following ground grouting.

Parameters of the gas in the 81105 gob borehole prior to and following ground grouting.</p

Fissures on 81107 working face ground.

Fissures on 81107 working face ground.</p

Variations of gases concentration and air leakage quantity of 81107 working face as mining progressed.

Variations of gases concentration and air leakage quantity of 81107 working face as mining progressed.</p