241 research outputs found
Continued Monitoring and Modeling of Xingfeng Solid Waste Landfill Settlement, China, Based on Multiplatform SAR Images
No full textContinued settlement monitoring and modeling of landfills are critical for land redevelopment and safety assurance. This paper adopts a MTInSAR technique for time-series monitoring of the Xingfeng landfill (XFL) settlement. A major challenge is that the frequent and significant settlement in the initial stage after the closure of landfills can affect the coherence of interferograms, thus hindering the monitoring of settlement by MTInSAR. We analyzed the factors that can directly affect the temporal decorrelation of landfills and adopted a 3D phase unwrapping approach to correct the phase unwrapping errors caused by such deformation gradient. SAR images from four platforms, including 50 Sentinel-1A, 12 Radarsat-2, 4 ALOS-2, and 2 TerraSAR-X/TanDEM-X images, are collected to measure the settlement and thickness of the landfill. The settlement accuracy is evaluated by a cross-evaluation between Radarsat-2 and Sentinel-1A that have similar temporal coverages. We analyzed the spatial characteristics of settlement and the relationship between the settlement and thickness. Further, we modeled the future settlement of the XFL with a hyperbolic function model. The results showed that the coherence in the initial stage after closure of the XFL is primarily affected by temporal decorrelation caused by considerable deformation gradient compared with spatial decorrelation. Settlement occurs primarily in the forward slope of the XFL, and the maximum line-of-sight (LOS) settlement rate reached 0.808 m/year from August 2018 to May 2020. The correlation between the settlement and thickness is 0.62, indicating an obvious relationship between the two. In addition, the settlement of younger areas is usually greater than that of older areas
Schematic mechanism of NaOH pretreatment of coal to enhance biomethane production modified from Liu et al (2015) [46].
No full textSchematic mechanism of NaOH pretreatment of coal to enhance biomethane production modified from Liu et al (2015) [46].</p
AOD and FMF dataset retrieved from NNAero in eastern and northern China from 2010 to 2020
No full textIn this work, the development of an artificial Neural Network for AEROsol retrieval (NNAero) is presented. NNAero uses data from the NASA MODerate resolution Imaging Spectroradiometer (MODIS) flying on the NASA Terra and Aqua satellites. The MODIS-derived spectral reflectances of solar radiation at the top of the atmosphere (TOA) and at the surface were used together with ground-based Aerosol Robotic Network (AERONET) measurements of Aerosol Optical Depth (AOD) and FMF to train a Convolutional Neural Network (CNN) for the joint retrieval of FMF and AOD. The NNAero results over northern and eastern China were validated against an independent reference AERONET dataset (i.e. not used in training the CNN). The results show that 68% of the NNAero AOD values are within the MODIS expected error (EE) envelope over land of ± (0.05 + 15%), which is similar to the results from the MODIS Deep Blue (DB) algorithm (63% within EE), and both are better than the Dark Target (DT) algorithm (31% within EE). The validation of the NNAero FMF vs AERONET data shows a significant improvement with respect to the DT FMF, with Root Mean Squared Prediction Errors (RMSE) of 0.1567 (NNAero) and 0.34 (DT). The NNAero method shows the potential of improved retrieval of the FMF.
If you use this dataset for related scientific research,please cite the below-listed corredponding references first(Chen X et al. ,RSE, 2020 )
Chen, X., de Leeuw, G., Arola, A., Liu, S., Liu, Y., Li, Z., & Zhang, K. (2020). Joint retrieval of the aerosol fine mode fraction and optical depth using MODIS spectral reflectance over northern and eastern China: Artificial neural network method. Remote Sensing of Environment, 249, 112006.https://doi.org/10.1016/j.rse.2020.112006If you have any questions,please contact me(Email: [email protected])
Research on the Correlation between English Scores in College Entrance Examination and Learning Strategies for Students of International Cooperative Education Program
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List of bird species in the breeding season of 2020 in the Zhoushan Archipelago, China
No full textList of bird species in the breeding season of 2020 in the Zhoushan Archipelago, China
Duorun Wang1, #, Yuhao Zhao1, #, Shupei Tang1, Xiangxu Liu1, Wande Li1, Peng Han1, Di Zeng1, Yangheshan Yang1, Guangpeng Wei1, Yi Kang1, Xingfeng Si1*
1 Institute of Eco-Chongming (IEC), Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China;
# These authors contributed equally to this work and should be considered co-first authors;
* Corresponding author: Xingfeng Si: [email protected]
We surveyed bird assemblages on study islands in Zhoushan Archipelago in the breeding season of 2020 (from April to June). We setup transects on each island to cover various habitat types for birds except highly urbanized regions (i.e., cities and towns). For the largest island (Island 1: Zhoushan Island), we set eight transects. For the rest of study islands, we set one, two, or four transects that the number of transects was based on the area and land-use types of study islands. We used Global Positioning System (GPS) to record the position and the length of each transect. The transect length is 2 km on most study islands. However, the transect length is restricted to 1 km for several small islands, as the steep terrain (e.g., cliffs near the edges) does not allow us to set a 2-km transect.
For bird surveys, at least two well-trained surveyors walked at a constant speed (ca. 1.5 km/h) along transects and recorded the identities and abundances of all birds heard and seen. Bird surveys were conducted two hours after sunrise and one hours before sunset, and the overall surveying time was restricted to two hours in each survey. We only conducted bird surveys on days with good weather conditions, excluding heavy raining or strong windy days. All transects were surveyed twice which is the maximum survey effort we can afford due to the large region of the Zhoushan Archipelago, the limited transportations in this region and the relatively short period of the breeding season. Surveyors walked the transects in a random order by inversing the starting point to avoid survey biases.</p
Research on qualities of compact spun silk yarn
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Purpose
Spun silk is one of the top grade textile materials, and its products have high added value and meet the needs of the market. However, the technology level and process design of silk spinning are still much lower than cotton spinning; especially singeing is applied on spun silk yarn, and generates waste materials. The purpose of this paper is to introduce a kind of pneumatic compact spinning, four-line compact spinning (FLCS), into silk spinning and study the corresponding spun yarn qualities.
Design/methodology/approach
First, taking the silk spinning frame FK501 as an example, the process of modification of FLCS is presented. Then, three kinds of spun silk yarns, 80 Nm (12.5tex), 100 Nm (10tex) and 120 Nm (8.3tex), are spun on the common silk spinning frame FK501 and the spinning frame modified with FLCS. The evenness, breaking strength and hairiness of spun yarns are tested and comparatively analyzed. After the ply yarn production, three singeing procedures should be applied on the ring ply yarns, while only two singeing procedures should be applied on the compact ply yarns, which is beneficial for material saving.
Findings
The results show that compared with ring spun silk yarns, the comprehensive quality of compact spun silk yarns is improved, especially the harmful long hairiness (=3 mm) of yarn. Compared with the single spun silk yarn, the comprehensive qualities of the ply yarn are improved; especially, the breaking strength of the ply yarns is two times larger than the single yarn. After singeing, the hairiness of the ply yarn is decreased greatly, and the evenness is also improved, while the strength is decreased. Compared with ring spun silk yarn, the singeing times of compact spun silk yarn can be decreased, and the gas consumption in each singeing is also decreased, which is beneficial for material saving.
Originality/value
In this paper, a kind of pneumatic compact spinning, FLCS, is introduced into the silk spinning. It is shown that compared with ring spun silk yarns, the comprehensive quality of compact spun silk yarns is improved, especially the harmful long hairiness (=3 mm) of yarn. After the ply yarn production, three singeing procedures should be applied on the ring ply yarns, while only two singeing procedures should be applied on the compact ply yarns, which is beneficial for material saving.
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Opinions on the Construction of “Mass Entrepreneurship and Innovation + Internationalization” Educational Ecosystem in Rail Transit Higher Vocational Colleges- Take Guangzhou Railway Polytechnic as an Example
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