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Hydrogen with small molecule size under high pressure can permeate most materials, being a challenge for rubber sealing materials used in hydrogen storage. The volume expansion of rubber materials due to high-pressure hydrogen is an Important indicator of their degradation and failure. Here, both microscopic calculations and experimental investigations of the nitrile rubber were conducted to evaluate the relation between the structure features and the expansion performance. Three factors, the acrylonitrile amount, the chain length, and the crosslinking degree, were considered to impact on the expansion of the nitrile rubber. Current study indicates that the increasing of acrylonitrile amount can result in the reduction of the volume expansion, owing to the preferential interactions between hydrogen and the butadiene group of nitrile rubber. Both of the chain length and the crosslinking degree are positively proportional to the chain elongation and then the volume of the nitrile rubber. Especially, the amount of acrylonitrile was found to be a key factor for evaluating the expansion of nitrile rubber under high-pressure hydrogen. This study performs microscopic calculations and macroscopic experiments to investigate the expansion of nitrile rubber, which is expected to be used in designing the sealing rubber material for high-pressure hydrogen storage applications. Highlights * Acrylonitrile determines the expansion performance of NBR within highpressure hydrogen. * Short chain and low crosslinking density suppressed the expansion of NBR. * Evaluating the expansion of nitrile rubber exposed to high-pressure hydrogen. KEYWORDS high-pressure hydrogen, molecular dynamic calculation, NBR O-rings, volume expansion, 1 | INTRODUCTION Hydrogen as a fuel is a good candidate for meeting the rapidly growing demand for energy in an environmentally friendly way. (1-3) However, the low-volume energy density [...]

In this study, the effects of soil conditioners on the growth and development of melons and the rhizosphere soil environment were explored. The optimal amount of added soil conditioner was screened to solve the practical production problems of high-quality and high-yield thin-skinned melon. The melon variety "Da Shetou" was used as the material. Under the conditions of conventional fertilization and cultivation technology management, different soil conditioners were set up for potted melons. The effects of Pastoral soil (CK), 95% Pastoral soil + 5% volcanic ash soil conditioner (KT1), 85% Pastoral soil + 15% volcanic ash soil conditioner (KT2), 75% Pastoral soil + 25% volcanic ash soil conditioner (KT3), 65% Pastoral soil + 35% volcanic ash soil conditioner (KT4), and 55% Pastoral soil + 45% volcanic ash soil conditioner (KT5) on melon yield, quality, and rhizosphere soil characteristics were investigated. The soil microbial community was analyzed using Illumina MiSeq technology. Compared to CK, KT1, KT3, KT4, and KT5, the KT2 treatment could improve the single fruit yield of melon, increasing it by 4.35%, 2.48%, 2.31%, 5.92%, and 2.92%. Meanwhile, the highest contents of soluble protein, soluble solid, and soluble sugar in the KT2 treatment were 1.89 mg·100 g−1, 16.35%, and 46.44 mg·g−1, which were significantly higher than those in the control treatment. The contents of organic matter, total nitrogen, alkali-soluble nitrogen, nitrate nitrogen, ammonium nitrogen, available potassium, and available phosphorus in melon rhizosphere soil were the highest in the KT2 treatment. Through Alpha diversity analysis, it was found that the Chao1 index, Shannon index, and ACE index were significantly higher in the KT1 treatment than in the control, while, among all groups, the Simpson index and coverage were not significantly different. The dominant bacteria in the six treated samples were mainly Actinobacteriota, Proteobacteria, Cyanobacteria, Chloroflexi, Acidobacteria, Bacteroidetes, Myxomycota, Firmicutes, Gemmatimonadota, Verrucomicrobia, and Planctomycetes, which accounted for 96.59~97.63% of the relative abundance of all bacterial groups. Through redundancy analysis (RDA), it was found that the organic matter, electrical conductivity, available phosphorus, and nitrate nitrogen of melon rhizosphere soil were the dominant factors of bacterial community change at the dominant genus level. In summary, 15% ash soil conditioner applied on melon was the selected treatment to provide a theoretical reference for the application of soil conditioner in facility cultivation. [ABSTRACT FROM AUTHOR]

Modifying VNU-18 (a MOF with a partial cone-sql layer pillared by the chains of pillars decorated with OH−) by substitution of OH− with Cl−, a new isoreticular structure, [Cu6(L)5·(Cl−)2·H2O·4DMF]·4DMF·6(H2O) (SNNU-Bai67, SNNU-Bai = Shaanxi Normal University Bai's group), has been successfully synthesized. Furthermore, we deeply investigated the selective C2 hydrocarbon separation properties of SNNU-Bai67 and VNU-18 by single-component gas adsorption experiments, breakthrough experiments and simulation studies. They exhibit highly selective adsorption for C2 hydrocarbons over CH4 compared to many reported MOFs for the separation of C2 hydrocarbons from CH4, due to the suitable pore sizes of the partial corn sql-layer built from the isophthalic acid analogy and Cu-paddlewheel units. Interestingly, with the counterion of OH− in VNU-18 tuned by Cl− in SNNU-Bai67, the adsorption uptake values of C2 hydrocarbons were apparently improved by 15.0% for C2H2, 20.4% for C2H4 and 25.3% for C2H6, respectively, while the IAST selectivities of C2 hydrocarbons/CH4 were still nearly the same, which may be because the synergistic effect of interactions of HC2/1⋯OCOO, HC2/1⋯N/CPy, HPy⋯CC2, π⋯π or HC2⋯CC2 between the gas molecules and the framework is enhanced by the weaker polarity of Cl− decorating the framework. [ABSTRACT FROM AUTHOR]

Modifying VNU-18 (a MOF with a partial cone-sql layer pillared by the chains of pillars decorated with OH−) by substitution of OH− with Cl−, a new isoreticular structure, [Cu6(L)5·(Cl−)2·H2O·4DMF]·4DMF·6(H2O) (SNNU-Bai67, SNNU-Bai = Shaanxi Normal University Bai's group), has been successfully synthesized. Furthermore, we deeply investigated the selective C2 hydrocarbon separation properties of SNNU-Bai67 and VNU-18 by single-component gas adsorption experiments, breakthrough experiments and simulation studies. They exhibit highly selective adsorption for C2 hydrocarbons over CH4 compared to many reported MOFs for the separation of C2 hydrocarbons from CH4, due to the suitable pore sizes of the partial corn sql-layer built from the isophthalic acid analogy and Cu-paddlewheel units. Interestingly, with the counterion of OH− in VNU-18 tuned by Cl− in SNNU-Bai67, the adsorption uptake values of C2 hydrocarbons were apparently improved by 15.0% for C2H2, 20.4% for C2H4 and 25.3% for C2H6, respectively, while the IAST selectivities of C2 hydrocarbons/CH4 were still nearly the same, which may be because the synergistic effect of interactions of HC2/1⋯OCOO, HC2/1⋯N/CPy, HPy⋯CC2, π⋯π or HC2⋯CC2 between the gas molecules and the framework is enhanced by the weaker polarity of Cl− decorating the framework. [ABSTRACT FROM AUTHOR]