Spatial Expansion and Soil Organic Carbon Storage Changes of Croplands in the Sanjiang Plain, China

Soil is the largest pool of terrestrial organic carbon in the biosphere and interacts strongly with the atmosphere, climate and land cover. Remote sensing (RS) and geographic information systems (GIS) were used to study the spatio-temporal dynamics of croplands and soil organic carbon density (SOCD) in the Sanjiang Plain, to estimate soil organic carbon (SOC) storage. Results show that croplands increased with 10,600.68 km2 from 1992 to 2012 in the Sanjiang Plain. Area of 13,959.43 km2 of dry farmlands were converted into paddy fields. Cropland SOC storage is estimated to be 1.29 ± 0.27 Pg C (1 Pg = 103 Tg = 1015 g) in 2012. Although the mean value of SOCD for croplands decreased from 1992 to 2012, the SOC storage of croplands in the top 1 m in the Sanjiang Plain increased by 70 Tg C (1220 to 1290). This is attributed to the area increases of cropland. The SOCD of paddy fields was higher and decreased more slowly than that of dry farmlands from 1992 to 2012. Conversion between dry farmlands and paddy fields and the agricultural reclamation from natural land-use types significantly affect the spatio-temporal patterns of cropland SOCD in the Sanjiang Plain. Regions with higher and lower SOCD values move northeast and westward, respectively, which is almost consistent with the movement direction of centroids for paddy fields and dry farmlands in the study area. Therefore, these results were verified. SOC storages in dry farmlands decreased by 17.5 Tg·year−1 from 1992 to 2012, whilst paddy fields increased by 21.0 Tg·C·year−1

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Pedestrian crash risk assessment and intervention

This article is aimed at identifying the main risk behaviors of pedestrians, sorting them on the basis of risk levels, and, moreover, performing risk assessment and intervention for the pedestrian. In order to achieve this goal, this article analyzes a large amount of traffic accident data in Beijing and finds that the movable sight obstacle is an important cause for traffic accident between pedestrians and motor vehicle (hereinafter referred a vehicle–pedestrian accident). Some tables and figures display when and where the movable sight obstacle usually occurs and also shows their logical relationship with other causes. Based on the results of investigation and analysis, the vehicle–pedestrian mechanism diagram was established using the method of fault tree analysis. The diagram shows some key factors and their effect level leading to the accident. The key importance coefficient model was adopted to estimate the function of individual risk behavior quantitatively during the processing of accident. In order to take advantage of the key importance coefficient model, the following research was conducted: first, we analyzed traffic accident data from 2005 to 2014 to find common pedestrians risk behaviors. Second, since traffic accidents and movable sight obstacle are closely related to motor vehicle violations, we collected and analyzed the data of traffic enforcement from 2007 to 2014. Finally, taking into account the individual preferences of policemen, we interviewed 200 police officers and others to calibrate our estimates. Through these efforts, we sorted the pedestrians’ risk behaviors in table. Unlike past research, the object of this study is pedestrian risk behaviors and faults. Furthermore, we also gained understanding to the mechanism of vehicle–pedestrian accident, which was already applied to assessment and intervention for pedestrians in some primary schools in Beijing

DAMAGE IDENTIFICATION STUDY OF PLATE STRUCTURES BASED ON WAVELET METHOD

The location and size assessment of different boundary conditions of plate and the effect of the sensor arrangement and noise for damage identification were carried. The principal process includes: firstly,the natural feature parameters of intact and damaged structures were obtained by the finite element modal analysis of thin plate. Modal nodes displacement data of the rectangle thin plate was decomposed and evaluated using the discrete wavelet transform,and the high frequency information and singular value of the damage location were received. Secondly,damage identification of plate structure under different boundary conditions were performed,and the quantity estimation of damage degree is estimated quantitatively by the change rate of the maximize value of wavelet coefficients. Finally,wavelet coefficient of 4 clamped constraints is bigger than that of 4 simply supported constraints about 0. 5%,and 0. 88% comparing to the 2 clamped constrains. The cases of the size of grid g = 40 m and wavelet de-noising for signal are able to identify plate’s damage,effectively. The study results show that this method is valid for the damage identification of location and damage severity of 2 D plate,which can be expected to provide some thinking and reference value for vehicle structures’ damage identification

DAMAGE IDENTIFICATION OF BEAM STRUCTURE BASED ON HYBRID NEURAL GENETIC ALGORITHM

It has established that a crack has an important effect on the dynamic behavior of a structure.To identify the location and depth of a crack on a structure,a method is presented which uses hybrid neuro-genetic technique.This method combines genetic algorithm（GA） with neural network,and uses genetic algorithm to optimize the BP network.Though the finite element analysis,acquire the first three natural frequencies of the beam,which used as inputs into neural network models for damage assessment.Genetic algorithm（GA） optimizes the weights and thresholds of the network,and using the optimization results as the initial value of the three layer BP neural network.Though the training of the sample data,then establish the suitable network.Finally,using the theoretical natural frequencies as the test values,obtain the predicted results of crack parameters.Comparing the theoretical value with the predicted value,the results show that this algorithm can identify the damage structure accurately

STRUCTURAL DAMAGE IDENTIFICATION BASED ON LMD SAMPLE ENTROPY AND RBF NETWORK

Adaptive time frequency analysis based on local mean decomposition and nonlinear quantization ability of sample entropy,combined with radial basis function（ RBF） neural network. A method of structural damage identification based on local mean decomposition（ LMD） sample entropy and radial basis function neural network is proposed. Firstly,the original signal is decomposed into a number of product function components（ PF component） by LMD to the original signal of structure vibration.Then extract the sample entropy of the first 3 PF components to realize the feature quantization of the PF component. Finally,the sample entropy of the component is used as the damage characteristic vector. The radial basis function neural network is used to identify the bottom plate of scaled carbody for high-speed train. The experimental results show that while this method is used to identify structural damage,the damage identification errors of location and degree are 96. 97% and 96. 25% respectively. The validity and accuracy of this method in structural damage diagnosis are proved

The strategy to achieve zero‑carbon in agricultural sector : does digitalization matter under the background of COP26 targets?

Under the background of Conference of the Parties (COP26) targets, how to propose sustainable development policies to achieve net zero emissions is very urgent. Internet development has promoted the intellectualization of agricultural environmental governance in China. This paper adopts DEA method and Tobit model to computes the agricultural energy conservation and emission reduction efficiency, and threshold regression model to study the connection between internet advancement and the China's agricultural energy conservation and emission reduction efficiency. The emergence of the internet has a substantial beneficial influence on agricultural energy conservation and emission reduction efficiency, as demonstrated by empirical findings, and this conclusion holds true even after considering potential endogeneity. Moreover, the estimates of the threshold regression model demonstrate the rise of the internet has a double-threshold effect on China's agricultural green total factor energy efficiency (ATFEE). Specifically, the impact of internet advancement on agricultural energy conservation and emission reduction efficiency exhibits a trend of initially increasing and then declining with the regional industrial structure optimization, development of education, and technology enhancement. Therefore, digitalization takes an important part in achieving zero emissions in the agricultural sector

The Performance of TiAlSiN Coated Cemented Carbide Tools Enhanced by Inserting Ti Interlayers

To enhance the cutting performance of TiAlSiN coated cemented carbide tools by inserting Ti interlayers and to explore their mechanism, TiAlSiN/Ti multilayer coatings with different Ti thicknesses, including 0 nm, 25 nm, 50 nm, 100 nm, and 150 nm, were deposited onto cemented carbide (WC-10 wt%, Co) substrates by high power impulse magnetron sputtering (HiPIMS). The microstructure, hardness, grain orientation, residual stress, adhesion, and toughness of those coatings were measured, and the cutting performance against Inconel 718 was analyzed. Meanwhile, finite element method (FEM) indentation simulations were performed to gain detailed insight into the effects of Ti interlayer thickness on mechanical properties of TiAlSiN/Ti multilayer coatings. Results demonstrated that mechanical properties of TiAlSiN multilayer coatings were significantly changed after the Ti interlayer was introduced, and the multilayer coating #M2 with 25 nm Ti layer showed the excellent toughness and adhesion without sacrificing hardness too much. As Ti interlayer thickness increased, both toughness and adhesion decrease owing to the plastic mismatch between individual layers, and these changes were discussed detailedly with finite element method. Moreover, the result of the cutting experiment also revealed that the tool flank wear Vb can be reduced by the multilayer structure. This improvement is believed to be due to the increasing toughness, which alleviated the damage caused by the continuous impact load of hard phases generated by Inconel 718 during cutting

The regulation of electro-optical properties and polymer morphology of polymer-dispersed liquid crystal films with silicon nanostructure

In this work, the thiol modified silica nanostructures (SiO2-SH) were doped into polymer-dispersed liquid crystal (PDLC) films. The SEM was used to observe the morphology of the polymer microstructure. The electro-optical (E-O) property test was determined by a liquid crystal parameter tester. The SEM images suggested that the SiO2-SH nanoparticles can react with acrylate groups to form the polymer matrix. The saturation voltage decreased by half in the sample when the dosage of the SiO2-SH nanoparticles was 7.5 wt%, which may be due to the reduced anchoring strength of the polymer matrix incorporated with silicon nanoparticles resulting from the lower surface energy and the enhanced steric repulsions of LC droplets and polymer matrix. In addition, the preparation conditions like polymerisation temperatures and UV light intensity also effectively regulated the E-O properties and polymer microstructure of the PDLC film with silica nanostructure. Thus, the results showed that the E-O properties and the polymer morphology of PDLC films with silicon nanostructures can be effectively regulated by doping SiO2-SH nanoparticles and regulating the preparation conditions such as the polymerisation temperature and UV light intensity. This work can provide practical guidance for modulating the properties of PDLC films.</p