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Highly sensitive detection of nitric dioxide (NO2) has recently attracted much attention due to its harmful to the human health even at a low concentration of 0.1 parts per million (ppm). Herein, In2O3 nanoparticles (NPs) were prepared via a facile ionic liquid (IL) assisted solvothermal method with subsequent calcination and then were analyzed through the characterization of X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and nitrogen adsorption–desorption techniques. Morphological characterization demonstrated that the resultant compounds were In2O3 NPs with a diameter ranging from 20 to 30 nm. The gas sensor based on the In2O3 NPs prepared with IL exhibited excellent NO2-sensing properties in terms of fast response/recovery speed (26.6/10.0 s), high response (310.0), good repeatability and long-term stability to 10 ppm NO2 gas at low working temperature of 92 °C. The gas-sensing mechanism of In2O3 NPs to NO2 was represented to the surface adsorption control model and the possibilities relating to the improved NO2 sensing performance of the In2O3 NPs synthesized with IL-assisted were also discussed in detail. [ABSTRACT FROM AUTHOR]

The performance of natural fiber reinforced polymer (NFRP) in the flexural strengthening of reinforced concrete (RC) beams is evaluated and optimized in this paper. The optimization comprehensively considers the structural performance, cost efficiency and environmental impacts. Main design parameters – such as the fabrication, the bond condition and the section shape of NFRP laminates – are investigated. The test results revealed that the partial bonded NFRP laminates tended to increase the flexural stiffness within the elastic range. Given the same reinforcement ratio, narrow and thick NFRP yielded the best structural performance. The prefabrication of NFRP laminates using vacuum infusion method greatly decreased the volume fraction of epoxy resin and the related environmental impacts without changing structural performance. The assessment of material cost and environmental impacts indicated that the prefabrication NFRP laminates had obvious advantages over the carbon FRP laminates. [ABSTRACT FROM AUTHOR]

The architecture of PO43− modified 2D TiO2 nanosheets was constructed by ionic liquids (ILs)-assisted hydrothermal method. The nanosheet structure can be regulated by the addition of different amount of ionic liquid. Using the composite nanosheets a chemoresistive gas sensor was prepared for trimethylamine (TMA) detection. Most reported TMA sensors need to be operated at a relatively high operating temperature, but in this paper, the as-synthesized PO43−-modified 2D TiO2/Ti2O(PO4)2 nanosheet sensor has high response (S = 87.46), short response time (14.6 s), and good reproducibility to 100 ppm TMA gas, when the temperature is 170 °C. In contrast to the single-phase TiO2 sensor, the gas-sensing property of the composite one is obviously enhanced. Moreover, its response shows excellent linear relationship with TMA concentration from 0.2 to 500 ppm, and a detection limit of 0.2 ppm. The TMA detection mechanism was investigated by analyzing the changes of the surface adsorption oxygen content by XPS and gaseous products using gas chromatography after the sensor was in contact with TMA. [ABSTRACT FROM AUTHOR]

A large number of salt caverns by solution mining are abandoned widely. After reasonable reformation, some of these caverns are expected to store energies, such as petroleum, natural gas, and compressed air energy. Different from other countries, salt formations of China are mainly bedded with lower thickness. In order to improve the mining efficiency of bedded salt formations, solution mining with double-well convection is widely adopted, which brings more horizontal caverns with larger dimensions and also larger roofs. When these horizontal caverns are transformed into underground energy storage, the layered roofs are easily suffered from unbalanced deformation and failure, and then become the channels of oil or gas leakage. Therefore, a series of theoretical analysis and numerical simulation were carried out to reveal the failure mechanism and stability of the bedded roof, and then some meaningful conclusions are acquired. Firstly, in the overlying strata, the argillaceous anhydrite layer is the key roof in the selection of the abandoned horizontal cavern for energy storage. Secondly, according to plate theory, the invalid of the bedded key roof needs to be treated into failure and instability respectively. Thirdly, the analysis on the vertical and horizontal stress in the key roof shows that it does experience a second type of instability. Finally, in order to maintain the stability of bedded key roof, the main influence factors require careful and comprehensive consideration, including the length of the long side, the thickness of the protective salt layer, and the internal pressure. [ABSTRACT FROM AUTHOR]

Tectonic movement is closely related to earthquake preparation. Across-fault sites and InSAR data are applied to reveal crust deformation from different precision, different temporal scale, and different spatial scale. In this paper, Xianshuihe fault zone is taken as an example; dislocation model in near-fault field is derived from screw dislocation model proposed by Savage and Burford (1973), which can reveal the locking information of the across-fault site using baseline data. Locking depth of each across-fault site on Xianshuihe fault zone is calculated using baseline data, which indicates that the locking depth of Laoqianning across-fault site is about 18 km and the locking depth of other sites is shallow. Time series analysis of SBAS-InSAR is used to study interseismic tectonic deformation. Deformation field from InSAR reveals the left-lateral slip property of Xianshuihe fault zone. The average locking depth is about 2-4 km calculated by the pixels' slip rate around in near-fault field, which indicates that locking depth is shallow and consistent using InSAR data as well as across-fault data. Screw model is used to obtain the best-fitting result of fault locking depth and slip rate. Layered dislocation model is put forward to explain shallow locking depth of fault zone. According to the theory of fault-slip deficit and seismic moment equilibrium, accumulative seismic moments caused by fault slip and the release amount of MS ≥ 5.0 earthquakes are calculated to estimate seismic risk of study area. All results indicate that Qianning segment of Xianshuihe fault zone is the future danger area with strong earthquakes. [ABSTRACT FROM AUTHOR]

The toxicity of soil irrigated with treated domestic wastewater (site A) and untreated gray wastewater (site B) were investigated. Soil extracts were prepared using distilled water, acid solvent (0.1 mol·L HCl), and organic solvent (acetone:petroleum ether: cyclohexane = 1:1:1) to understand the type of pollutants responsible for the ecotoxicity associated with wastewater irrigation. The soil toxicity was assessed using a luminescence inhibition assay with Vibrio fischeri for acute toxicity, a micronucleus assay with Vicia faba root tips and a single cell gel electrophoresis assay of mice lymphocytes for genotoxicity. The physicochemical properties and the heavy metal (HM) contents of the irrigated soil were also analyzed. The results indicated that the wastewater irrigation at site A had no effects on the soil properties. With the exception of Pb, Zn, Fe, and Mn, the accumulation of HMs (Cu, Ni, and Cr) occurred. However, the irrigation at site A did not result in obvious acute toxicity or genotoxicity in the soil. The soil properties changed greatly, and HMs (Cu, Ni, and Cr) accumulated in site B. There were significant increases in the acute toxic and genotoxic effects in the soils from site B. The ecotoxicity in site B came primarily from organic-extractable pollutants. [ABSTRACT FROM AUTHOR]

In the present paper, ramie fiber reinforced polymer (RFRP) plates prepared by hot compression process were subjected to water immersion at 20 oC and 40 oC for four weeks, and the variation of water uptake and mechanical properties with immersion time were investigated. It was found that the saturated water content and the coefficient of diffusion in RFRP were much higher than those in synthetic fiber based composites, due to the strong hydrophilic characteristic of the ramie fiber. After fully drying of the immersed samples, mass loss from 1.6 % to 3.6 % was found, indicating occurrence of a serious hydrolysis of the resin and the ramie fibers. After a short term of immersion (i.e., 1 day), RFRP showed a remarkable deterioration in the flexural and short beam shear properties. Further increase of the immersion time, the degradation rate of the mechanical properties was much reduced. After fully drying, the mechanical properties of the samples can be recovered to some extent, but still much less than the original values. The variation of mechanical property as a function of the water uptake content exhibits three stages (i.e., dramatic reduction, leveling off and quick decrease again). This may be due to the sequent occurrence of the degradation of natural fibers, fiber debonding and hydrolysis of the fiber and resin during immersion. [ABSTRACT FROM AUTHOR]