Occurrence and characteristics of microplastics in soils from greenhouse and open-field cultivation using plastic mulch film

There is a major knowledge gap concerning the extent of microplastic pollution in agronomic regions of China, which represent a plastic use hotspot. In order to clarify the amendment of agronomic region and plastic film mulching mode to microplastics distribution, the characteristics of microplastics distributed in agricultural soils from three typical regions (Beijing (BJ), Shandong (SD), and Xinjiang (XJ)) with two plastic film mulching modes (greenhouse (G) and conventional field-based film mulching (M)) in China were investigated. Microplastics weight and their response to planting regions were also evaluated in this study. The result showed that the average abundance of microplastics in soils from BJ, SD, and XJ was 1.83 × 104 items kg-1, 4.02 × 104 items kg-1, and 3.39 × 104 items kg-1, and the estimated weight of microplastics per kg of dry soils was 3.12 mg kg-1, 5.63 mg kg-1, and 7.99 mg kg-1, respectively. Microplastics in farmland were mainly of small particle size (50 to 250 μm), with their abundance decreasing with increasing particle size. Among the microplastics detected, polyethylene and polypropylene were the two dominant types present, accounting for 50.0% and 19.7%, respectively. The standard total effect of planting regions on microplastic number and weight was 31.8% and 32.3%, and plastic film mulching modes (G vs. M) could explain 34.4% of the total variation of microplastic compositions with a contribution rate of 65.6% in this study. This research provides key data for an assessment of the environmental risk of microplastics and supports the development of guidelines for the sustainable use of agricultural plastic film. Further, it is necessary to quantify and assess the contribution of other different plastic sources to microplastics in soil. Big data technologies or isotope tracer techniques may be promising approaches.</p

Sr\u3csub\u3e2\u3c/sub\u3eFe\u3csub\u3e1.5\u3c/sub\u3eMo\u3csub\u3e0.5\u3c/sub\u3eO\u3csub\u3e6-δ\u3c/sub\u3e – Sm\u3csub\u3e0.2\u3c/sub\u3eCe\u3csub\u3e0.8\u3c/sub\u3eO\u3csub\u3e1.9\u3c/sub\u3e Composite Anodes for Intermediate-Temperature Solid Oxide Fuel Cells

Sr2Fe1.5Mo0.5O6−δ (SFM) perovskite is carefully investigated as an anode material for solid oxide fuel cells with LaGaO3-based electrolytes. Its electronic conductivity under anodic atmosphere is measured with four-probe method while its ionic conductivity is determined with oxygen permeation measurement. Samaria doped ceria (SDC) is incorporated into SFM electrode to improve the anodic performance. A strong relation is observed between SDC addition and polarization losses, suggesting that the internal SFM-SDC contacts are active for H2 oxidation. The best electrode performance is achieved for the composite with 30 wt% SDC addition, resulting in an interfacial polarization resistance of 0.258 Ω cm2 at 700◦C for La0.8Sr0.2Ga0.8Mg0.2O3−δ supported single cells. Electrochemical impedance spectroscopy analysis indicates that the high performance of SFM-SDC composite anodes is likely due to the high ionic conductivity and electro-catalytic activity of SDC by promoting the ionic exchange processes. Redox cycle treatment shows that SDC addition can even improve the redox tolerance of SFM anodes

Quantitative assessment of image motion blur in diffraction images of moving biological cells

Motion blur (MB) presents a significant challenge for obtaining high-contrast image data from biological cells with a polarization diffraction imaging flow cytometry (p-DIFC) method. A new p-DIFC experimental system has been developed to evaluate the MB and its effect on image analysis using a time-delay-integration (TDI) CCD camera. Diffraction images of MCF-7 and K562 cells have been acquired with different speed-mismatch ratios and compared to characterize MB quantitatively. Frequency analysis of the diffraction images shows that the degree of MB can be quantified by bandwidth variations of the diffraction images along the motion direction. The analytical results were confirmed by the p-DIFC image data acquired at different speed-mismatch ratios and used to validate a method of numerical simulation of MB on blur-free diffraction images, which provides a useful tool to examine the blurring effect on diffraction images acquired from the same cell. These results provide insights on the dependence of diffraction image on MB and allow significant improvement on rapid biological cell assay with the p-DIFC method

Research on dynamical characteristics of planetary gear system with tooth pitting

The dynamical characteristics research of planetary gear system with tooth pitting is useful for early fault diagnosis and monitor. However, it is an unsolved puzzle to establish the relationship between tooth pitting and dynamical characteristics. In this study, a pitting fault analytical model is proposed to investigate the effects of tooth pitting on the gear mesh stiffness. Then this mesh stiffness with tooth pitting is incorporated into a dynamical model of planetary gear system, and the effects of the tooth pitting on the vibration characteristics is investigated. The simulated results show that the time-varying mesh stiffness is reduced with tooth pitting propagations along width or depth direction. The mesh frequency and its harmonics are mainly frequencies components in the frequency spectrum of dynamic mesh force, but sidebands caused by the tooth pitting are more sensitive than the mesh frequency and its harmonics. The tooth pitting frequency and its harmonics also increase with the rising rotational speed of the sun gear. In addition, both relative statistical indicators of RMS and Kurtosis increase with the growth of tooth pitting size. But the relative indicators have different sensitivity on the vibration signal type. These results could supply some guidance to the condition monitoring and fault diagnosis of planetary gear system, especially to the gear tooth pitting at early stage

Pilotirani težnostni podporni zid: deformacijsko-napetostna analiza

The piled retaining wall is a new type of railway retaining structure in China. In the current design, the retaining wall, the beam and the piles are assumed to be independent components. Both the mutual action of the retaining wall, the piles and beam, and the influence of the soil or rock foundation on the structure are not fully considered, so that there are some limitations in the current design method. In this paper, using field observations and a three-dimensional finite-element analysis, the lateral earth pressure on the wall back, the stress distributions and the forces of the reinforcements in the beam and the pile were studied. The simulation results were in good agreement with the field observation data. These results revealed that the tensile stresses were very small and that these stresses were positive in most zones in the beam and the pile. It can also be observed that the tensile stresses or forces in the beam and pile obtained in this study were much smaller than those obtained using the current design method. This clarified the fact that the current design method used for the beam and the pile was very conservative and that it should be optimized to consider the effect of the foundation on the whole structure and the interactions among the different components.Pilotirani podporni zid predstavlja nov tip podpornih konstrukcij na železnicah na Kitajskem. V sedanji praksi projektiranja so podporni zid, greda in piloti obravnavani kot neodvisne komponente. Tako ni obravnavano vzajemno delovanje podpornega zidu, pilotov in grede ter ni popolnoma obravnavan vpliv zemljine ali hribine na konstrukcijo, kar predstavlja določene omejitve v veljavni metodi projektiranja. V članku je podana študija bočnih zemeljskih pritiskov na steno zidu, razporeditev napetosti ter sil v armaturi grede in pilotov, ki uporablja rezultate terenskih opazovanj in tridimenzionalnih analiz na osnovi končnih elementov. Rezultati simulacij se dobro ujemajo z rezultati terenskih meritev. Ti rezultati so pokazali, da so bile natezne napetosti zelo majhne in, da so bile napetosti v večina conah v gredi in pilotih natezne. Prav tako smo ugotovili, da so natezne napetosti ali sile v gredi in pilotu v tej študiji bile veliko manjše od nateznih napetosti dobljenih z veljavno metodo projektiranja. Razjasnili smo, da je veljavna metoda projektiranja za dimenzioniranje grede in pilotov zelo konzervativna in, da jo je potrebno optimizirati z obravnavanjem vpliva temelja na celotno konstrukcijo ter upoštevanjem interakcije vseh komponent, ki sestavljajo sistem

Frictional properties of antigorite under high pore fluid pressure

We present the figures in our paper, which is accepted by CJU and is in press now.</p

镱铝共掺杂氧化锆电解质材料制备与性能

The ytterbia and alumina co-doped zirconia electrolyte materials were synthsized by a solid-state method. The results revealed that Al_2O_3-doping was beneficial for sintering and increasing flexural strength.The effect of Al_2O_3-doping on ionic conductivity was in relation to the doping content of ytterbia.Only the ionic conductivity of sample with 6% (mole fraction)Yb_2O_3 was enhanced by alumina doping.6%(mole fraction)Yb_2O_3 and 0.5%(mole fraction)Al_2O_3 codoped zirconia electrolyte showed excellent bending strength and the best oxygen ionic conductivity.A maximum density of 0.40W/cm~2 was measured at 800℃ for the cell with this material as electrolyte