CONTROL OF STICKY CONTAMINANTS WITH CATIONIC TALC IN DEINKED PULP

In this study a cationic talc was applied to deinked pulp for control of sticky contaminants. Effects of the cationic talc on stickies and dissolved and colloid substances were investigated and compared with those of a conventional talc. Characteristics of wet-end chemistry were examined for the pulp with addition of both kinds of talc samples. Furthermore, influences on paper properties were also compared. The results showed that the addition of cationic talc can effectively decrease the content of stickies and DCS, while reducing the cationic demand of the pulp, and the turbidity of the filtrate. Deposition of stickies can be reduced by about 63% with the addition of 2.0% cationic talc into the pulp, and the DCS was reduced from 1989 mg/L to 1927 mg/L. Addition of cationic talc significantly increased the ash content of the paper, but it negatively influenced the paper strength properties

Two DsbA Proteins Are Important for Vibrio parahaemolyticus Pathogenesis

Bacterial pathogens maintain disulfide bonds for protein stability and functions that are required for pathogenesis. Vibrio parahaemolyticus is a Gram-negative pathogen that causes food-borne gastroenteritis and is also an important opportunistic pathogen of aquatic animals. Two genes encoding the disulfide bond formation protein A, DsbA, are predicted to be encoded in the V. parahaemolyticus genome. DsbA plays an important role in Vibrio cholerae virulence but its role in V. parahaemolyticus is largely unknown. In this study, the activities and functions of the two V. parahaemolyticus DsbA proteins were characterized. The DsbAs affected virulence factor expression at the post-translational level. The protein levels of adhesion factor VpadF (VP1767) and the thermostable direct hemolysin (TDH) were significantly reduced in the dsbA deletion mutants. V. parahaemolyticus lacking dsbA also showed reduced attachment to Caco-2 cells, decreased β-hemolytic activity, and less toxicity to both zebrafish and HeLa cells. Our findings demonstrate that DsbAs contribute to V. parahaemolyticus pathogenesis

Research on the Mode of China’s Power Spot Market

At present, the construction of China’s power spot market is advancing steadily. This paper studies the characteristics and functions of the spot market, analyses the market environment and requirements, studies the key elements and designs the market mode for the spot market under the new situation, and puts forward suggestions for some key problems in the actual operation. This paper can provide reference for promoting the top-level design and operation of China’s power spot market

Research on evaluation model of rock failure integrity under complex geological conditions in karst area

Blasting lumpiness prediction is one of the most important research contents in engineering blasting. Although the traditional KUZ-RAM model is widely used, it often overestimates the size of blasting. Therefore, the KUZ-RAM model was updated or corrected in this paper by simplifying the difficult problem of statistical burst fragmentation in LS-DYNA. Based on the theory of area measurement method, the fitting mechanism of machine learning is used to study the lumpiness of simulation results. The updated KUZ-RAM model adds a coefficient of 0.623 to the original equation of average lumpiness xm. The linear coefficient R2 between the predicted results and the field blasting results increases from −1.99 to 0.97, which significantly improves the prediction of blasting lumpiness

Deformation Detection and Attribution Analysis of Urban Areas near Dianchi Lake in Kunming Using the Time-Series InSAR Technique

The main city of Kunming is located on the north bank of Dianchi Lake. The complex geological environment, large-scale construction, and expansion of the city in recent years have caused uneven land surface subsidence and threatened public safety. In this study, Sentinel-1 ascending and descending orbit datasets were collected for the period of February 2018 to May 2021. The characteristics of surface displacement in the Kunming downtown area were monitored using the time-series interferometric synthetic aperture radar (InSAR) technique, and attribution analysis was performed. It was found that areas with more severe surface settlement were concentrated in the International Exhibition Center area and the large, newly built communities near Dianchi Lake and the Xiaobanqiao Region. The multifactor attribution analysis results demonstrated that the subsidence areas are concentrated in urban villages and engineered, construction-intensive areas in the lakeside sedimentary layer area, with the maximum displacement rate reaching −23.12 mm/a in the line-of-sight direction of the Sentinel-1 ascending dataset. The reliability of the InSAR results was cross-validated with ascending and descending results. This study provides a scientific reference for urban development planning and potential geological disaster detection in Kunming

GC-MS ANALYSIS OF STICKY CONTAMINANTS IN A DEINKING PULPING LINE

Pulps were sampled from three major points of a deinking pulping line and classified as fibers fraction, fines fraction, and aqueous phase, respectively, then extracted with tetrahydrofuran (THF) or methyl tert-butyl ether (MTBE). Sticky contaminants in the extractives were examined by GC-MS analysis. The results showed that the contaminants can be grouped as adhesive substances, wood extractives, lignin-derivatives, and other organic acids, of which the adhesive substances were accounted as the major component. Contents of sticky components in each group and their removal were further evaluated according to the related unit operation. Adhesives remaining in fibers and fines fractions were removed by the post-flotation. Wood extractives and degraded residual lignins were also released to some extent from pulp fibers during heat-dispersing, and then removed during the post-flotation

Overview, Evolution and Thematic Analysis of China’s Green Consumption Policies: A Quantitative Analysis Based on Policy Texts

Based on the 286 green consumption policy documents issued from 1989 to 2019 at the national level, we analyzed the stage of documents issued, the intergovernmental relationship network of the policy issuing units, and the evolution of the green consumption policy system. The results revealed that: (1) the development of green consumption policies had undergone three stages (i.e., initial stage, preliminary development stage, and deep development stage). For the issuing units, collaborative decision-making by multiple units is a significant phenomenon in the current green consumption policy field; (2) the green consumption policy focus had evolved from placing an initial emphasis on pollution control and clean production to constructing a circular economy and encouraging ecological environmental protection; (3) in respect to the research topic, the results of high-frequency keywords indicated that six clusters were generated, and these included industrial pollution, green product certification and labeling, resource conservation and energy-saving technological development, environmental protection and the energy ecological cycle, the low-carbon economy, and publicity and social participation

Accuracy Assessment of High-Resolution Globally Available Open-Source DEMs Using ICESat/GLAS over Mountainous Areas, A Case Study in Yunnan Province, China

The Open-Source Digital Elevation Model (DEM) is fundamental data of the geoscientific community. However, the variation of its accuracy with land cover type and topography has not been thoroughly studied. This study evaluates the accuracy of five globally covered and open-accessed DEM products (TanDEM-X90 m, SRTEM, NASADEM, ASTER GDEM, and AW3D30) in the mountain area using ICESat/GLAS data as the GCPs. The robust evaluation indicators were utilized to compare the five DEMs’ accuracy and explore the relationship between these errors and slope, aspect, landcover types, and vegetation coverage, thereby revealing the consistency differences in DEM quality under different geographical feature conditions. The Taguchi method is introduced to quantify the impact of these surface characteristics on DEM errors. The results show that the slope is the main factor affecting the accuracy of DEM products, accounting for about 90%, 81%, 85%, 83%, and 65% for TanDEM-X90, SRTM, NASADEM, ASTER GDEM, and AW3D30, respectively. TanDEM-X90 has the highest accuracy in very flat areas (slope < 2°), NASADEM and SRTM have the greatest accuracy in flat areas (2 ≤ slope < 5°), while AW3D30 accuracy is the best in other cases and shows the best consistency on slopes. This study makes a new attempt to quantify the factors affecting the accuracy of DEM, and the results can guide the selection of open-source DEMs in related geoscience research

Deformation Detection and Attribution Analysis of Urban Areas near Dianchi Lake in Kunming Using the Time-Series InSAR Technique

The main city of Kunming is located on the north bank of Dianchi Lake. The complex geological environment, large-scale construction, and expansion of the city in recent years have caused uneven land surface subsidence and threatened public safety. In this study, Sentinel-1 ascending and descending orbit datasets were collected for the period of February 2018 to May 2021. The characteristics of surface displacement in the Kunming downtown area were monitored using the time-series interferometric synthetic aperture radar (InSAR) technique, and attribution analysis was performed. It was found that areas with more severe surface settlement were concentrated in the International Exhibition Center area and the large, newly built communities near Dianchi Lake and the Xiaobanqiao Region. The multifactor attribution analysis results demonstrated that the subsidence areas are concentrated in urban villages and engineered, construction-intensive areas in the lakeside sedimentary layer area, with the maximum displacement rate reaching −23.12 mm/a in the line-of-sight direction of the Sentinel-1 ascending dataset. The reliability of the InSAR results was cross-validated with ascending and descending results. This study provides a scientific reference for urban development planning and potential geological disaster detection in Kunming

TEMPO/NaBr/NaClO-Mediated Surface Oxidation of Nanocrystalline Cellulose and Its Microparticulate Retention System with Cationic Polyacrylamide

TEMPO/NaBr/NaClO-mediated surface oxidation of NCC, acid-extracted from aspen kraft pulp, was studied, and the properties of nanocellulose whiskers before and after oxidation were characterized by conductimetry, Fourier transform infrared spectroscopy, X-ray diffraction, and atomic force microscopy. The resulting products with varied oxidation degrees were then applied in the deinked pulp to evaluate the improvements of fines retention and pulp drainage. It was found that TEMPO-oxidized NCC maintained its crystalline form of cellulose I, while it showed better dispersibility and smaller dimension due to the high level of carboxyl content and degree of oxidation. By adding NCC and TONCC to the deinked pulp, the retention was improved while the drainage rate was decreased to some extent. When TONCC samples were applied together with cationic polyacrylamide to constitute a microparticulate retention system, both fines retention and pulp drainage were apparently improved. Further study showed that the retention and drainage rate were significantly influenced by the degree of oxidation. TONCC sample with the highest DO (0.134) gave the highest retention and drainage rate, 89.6% and 9.41 mL/s, respectively