Application of thermal ignition theory of di Cao, Chen-Rui; Liu, Shang-Hao; Huang, An-Chi ...
Journal of thermal analysis and calorimetry,
07/2018, Letnik:
133, Številka:
1
Journal Article
A high reactive sulfocompound, sulfur monochloride, was chemically supported onto the surface of silica (silica-s-S2Cl2) by the reaction between chloric atom and silanol hydroxyl to obtain a novel ...vulcanizing agent, silica supported sulfur monochloride (silica-s-S2Cl2). Silica-s-S2Cl2 can be homogeneously dispersed in SBR matrix as a modifier and cure the styrene-butadiene rubber (SBR) without sulfur as a novel high-efficiency vulcanizing agent. The sulfur and Bis3-(triethoxysilyl)propyl Tetrasulfide (TESPT) silane coupling agent vulcanized SBR composites were mainly polysulfide crosslinks, on the contrary, the vulcanization by silica-s-S2Cl2 give priority to the mono- and disulfides crosslinks. The highlight of this work lies in the fact that apparent improvement has been achieved by novel and high efficient functional particles due to the silica surface supported with sulfur monochloride, which may open up new opportunities for the preparation of functional nano-fillers in rubber industry.
The stem COsub.2 efflux (Es) plays an important role in the carbon balance in forest ecosystems. However, a majority of studies focus on ecosystem flux, and little is known about the contribution of ...stem respiration to ecosystem respiration (Reco) for rubber (Hevea brasiliensis) plantations. We used a portable COsub.2 analyzer to monitor the rate of Es in situ at different heights (1.5 m, 3.0 m and 4.5 m) in an even-aged rubber plantation from 2019 to 2020. Our results showed that Es exhibited a significant seasonal difference with a minimum value in April and a maximum in September. The mean annual rate of Es at 3.0 m in height (1.65 ± 0.52 μmol·msup.−2·ssup.−1) was slightly higher than Es at 4.5 m in height (1.56 ± 0.59 μmol·msup.−2·ssup.−1) and Es at 1.5 m in height (1.51 ± 0.48 μmol·msup.−2·ssup.−1). No obvious differences in vertical variations were found. An area-based method (Ea) and a volume-based method (Ev) were used to estimate stem respiration at stand levels. One-way ANOVA showed that Ea had no obvious differences in vertical variation (p = 0.62), and Ev indicated differences in vertical variation (p < 0.05). Therefore, the Ea chamber-based measurements at breast height were reasonable and practical extrapolation proxies of stem respiration in an even-aged rubber plantation. With the use of the area-based method, the stem carbon values released from a mature rubber forest were estimated to be 1.214 t C·hmsup.−2·asup.−1 in 2019 and 1.414 t C·hmsup.−2·asup.−1 in 2020. Ea/Reco and Ev/Reco showed seasonal changes, with a minimum value in April and a maximum value in December. The leaf area index (LAI) and soil volumetric moisture content (VWC) were the major impact factors of Ea/Reco in an even-aged pure rubber plantation.
•Waste crumb rubber up to 5.5% replacement was evaluated as a potential substitute of fine aggregate for production of acid resistant concrete.•The formed minerals and molecular groups after acidic ...exposure were analysed through XRD and FTIR analyses.•FESEM and TGA/DTA analyses were employed to verify the changed microstructure after acidic exposure.•At 4% substitution level acid resistance improves.
Disposal of waste rubber is afflicting ecological balance across the globe. In recent years, the rate of dumping of this material has amplified. One possible approach to solve this issue is to utilize this rejected material as a replacement of fine aggregate in concrete. Hence, this study examines the behaviour of concrete with crumb rubber at various substitution levels (4%, 4.5%, 5% and 5.5%) under an acidic (sulphuric acid) aggressive environment. Performance was judged by evaluating change in weight, compressive strength and microstructure. Results show that with inclusion of crumb rubber, material separation of concrete reduces which prevents its rupture and disintegration. This was verified by X-ray diffraction, fourier transform infrared spectroscopy, thermogravimetric analysis and field emission scanning electron microscopy tests. Hence, using crumb rubber as a replacement of fine aggregate up to 4% prevents significant fall in performance under such an aggressive condition. This will also reduce the dependency on natural fine aggregate for the manufacture of concrete for non-structural elements.
Transgenic technology is a crucial tool for gene functional analysis and targeted genetic modification in the para rubber tree (Hevea brasiliensis). However, low efficiency of plant regeneration via ...somatic embryogenesis remains a bottleneck of successful genetic transformation in H. brasiliensis. Enhancing expression of GROWTH-REGULATING FACTOR 4 (GRF4)-GRF-INTERACTING FACTOR 1 (GIF1) has been reported to significantly improve shoot and embryo regeneration in multiple crops. Here, we identified endogenous HbGRF4 and HbGIF1 from the rubber clone Reyan7-33-97, the expressions of which dramatically increased along with somatic embryo (SE) production. Intriguingly, overexpression of HbGRF4 or HbGRF4-HbGIF1 markedly enhanced the efficiency of embryogenesis in two H. brasiliensis callus lines with contrasting rates of SE production. Transcriptional profiling revealed that the genes involved in jasmonic acid response were up-regulated, whereas those in ethylene biosynthesis and response as well as the S-adenosylmethionine-dependent methyltransferase activity were down-regulated in HbGRF4- and HbGRF4-HbGIF1-overexpressing H. brasiliensis embryos. These findings open up a new avenue for improving SE production in rubber tree, and help to unravel the underlying mechanisms of HbGRF4-enhanced somatic embryogenesis.
Novel pseudo-polymeric complexes of gold(III)-mercury(II) with cyclic alkylene dithiocarbamate ligands: (Au{S.sub.2CN(CH.sub.2).sub.6}.sub.2HgCl.sub.3).sub.n, ...(Au{S.sub.2CN(CH.sub.2).sub.6}.sub.2.sub.2HgCl.sub.4 * H.sub.2O).sub.n, and (Au{S.sub.2CN(CH.sub.2).sub.4O}.sub.2.sub.2Hg.sub.2Cl.sub.6).sub.n have been obtained and structurally characterized. The sophisticated supramolecular structure of the obtained compounds is realized due to secondary non-valent Au ... S interactions and includes mononuclear and binuclear cations and anions as structural units as well as cationic and anionic polymer chains. The thermal behavior of the obtained complexes has been studied by means of simultaneous thermal analysis. The products of thermal transformations of the complexes are reduced elemental gold and HgCl.sub.2. Keywords: mercury(II) dithiocarbamates, chemisorption activity, gold(III)mercmy(II) dithiocarbamato-chlorido complexes, supramolecular self-assembly DOI: 10.1134/S1070363219110185
The reaction of secondary amines with CS.sub.2 under mild conditions using reduced graphene oxide (rGO) as a green catalyst was reported, which provided an efficient access to the one-pot synthesis ...of bis(aminothiocarbonyl)disulfides. The rGO can be recycled at least four times without any loss of catalytic activity. A plausible mechanism was proposed.
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![Variation of Stem CO[sub.2]...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/2071-1050/small "Variation of Stem CO[sub.2] Efflux and Estimation of Its Contribution to the Ecosystem Respiration in an Even-Aged Pure Rubber Plantation of Hainan Island")
