摘要：
The triple-bed circulating fluidized bed gasifier is a new type of the gasification process in which the combustion process, pyrolysis process, and gasification process of the fuel are carried out in different reactors. The inert heat carrier is used to transfer heat between the reactors. In this way, the gasification efficiency of char is improved since the tar and pyrolysis gas generated in the pyrolysis process will no longer hinder the gasification of the char. The thermodynamic equilibrium model is used to simulate the gasification process of the triple-bed circulating fluidized bed, and the sub-models are established to simulate combustion, pyrolysis, and gasification processes. The simulation results agree well with the experimental values. Besides, the model studies the effects of key parameters such as the gasification reaction temperature and the ratio of steam to C (S/C) on gasification performance. Results showed that higher gasification reaction temperature has a positive effect on gasification performance, S/C may not be too high, and excessive water vapor will directly affect the gasification reaction.
摘要：
This study investigated the passivation of multiple heavy metals (Cd, Cr, Cu, Zn, and Pb) in river sediments by composting with rice straw. The correlation between the selected environmental factors and the distribution of heavy metal fractions was assessed by multivariate analysis. The results suggested that the composting could reduce the bioavailability of Cu, Cd, Cr, and Pb. The influences of composting on the passivation of these five heavy metals are different. The greatest passivation of heavy metals is for Cd, which its bioavailability decreased 17.72%. The bioavailability of Cu, Pb, and Cr also partly decreased. However, there was almost no effect on the bioavailability of Zn. The results of multivariate analysis revealed that the predominant parameters affecting the variation of the bioavailability of different heavy metals were different in a complex composting system with multiple heavy metal pollution. While the variation partitioning analysis indicated that water-soluble carbon (WSC) was the statistically main factor affecting the bioavailability of Cd, Cr, Cu, Zn, and Pb. It provides a theoretical reference for optimizing the co-composting process in remediation of different heavy metal contamination in sediments.
作者机构：
[Huang, Changjun; Zhou, Qingshan; Cao, Yuanzhi] Hunan City Univ, Sch Municipal & Surveying Engn, Yiyang 413000, Peoples R China.;[Huang, Changjun] Key Lab Key Technol Digital Urban Rural Spatial P, Yiyang 413000, Peoples R China.;[Zhou, Lv] Guilin Univ Technol, Sch Geomat & Geoinformat, Guilin 541004, Peoples R China.
通讯机构：
[Changjun Huang] S;School of Municipal and Surveying Engineering, Hunan City University, Yiyang, China<&wdkj&>Key Laboratory of Key Technologies of Digital Urban-Rural Spatial Planning of Hunan Province, Yiyang, China
摘要：
Landslide is a global environmental geological hazard caused by natural or human activities. Since the impoundment of the Three Gorges reservoir area, the geological disasters such as collapses, landslides and other kinds of geological disasters increased obviously due to the periodic fluctuation of the water level in the Yangtze River. Wanzhou District is located in the center of the Three Gorges Reservoir Area, which plays an important role in the prevention and control of geological hazards in the whole Three Gorges Reservoir Area. This is because a large number of deep bedrocks old landslides are distributed among this region, such as Taibaiyan ancient landslide, Caojiezi ancient landslide, Anlesi ancient landslide, Pipaping ancient landslide, and Diaoyanping ancient landslide. In this study, Quasi-Persistent Scatterers InSAR (QPS-InSAR) time-series method is proposed to identify and monitor the ancient landslides in Wanzhou. In this method, the High-coherent test is applied to Quasi-Persistent Scatterers (PSC) selection, and PSC and persistent scatterer are combined to improve the density of measurement points in vegetation area. The QPS-InSAR method is also characterized by the appropriate combination of differential interferograms produced by a Minimum Spanning Tree and the employment of the phase triangulation algorithm to estimate the optimal phase. This technique was performed on 8 scenes of L-band ALOS PALSAR ascending data acquired during 2015-2018, then deformation rate maps and time series for ancient landslide were generated, which were applied to retrieve time series displacement for the large-scale landslide in Wanzhou District. The experiment results show that there are obvious landslide deformation patterns detected in this region with displacement velocity larger than - 21 mm/yr during the observation period. Finally, the influencing factors such as geological conditions, distribution of rainfall and reservoir water level change in the Three Gorges Reservoir area, and deformation mechanism of Wanzhou landslide are analyzed. The monitoring results will help the local government to carry out regular landslide inspection and strengthen landslide disaster early warning.
摘要：
Indoor thermal environment significantly affects human health and comfort. Although several studies have investigated this aspect in numerous buildings, a gap exists with regard to the hospital waiting areas and the thermal comfort of pregnant women. Therefore, this study assessed the ambient conditions in the waiting areas of obstetric departments in four Guangzhou hospitals during summer and winter and conducted a questionnaire survey on pregnant women and males & non-pregnant female patients in the waiting areas to analyze the differences in their thermal sensation. A total of 2594 questionnaire responses were collected during the survey period, including 1477 and 1117 responses during summer and winter, respectively. Further, the predicted mean vote (PMV) model was applied to evaluate the thermal comfort and differences in the thermal sensation between pregnant women and escorts. The results indicated that the PMV model could not accurately predict the thermal comfort of the subjects and overestimated their thermal sensation. Additionally, the acceptable operative temperature ranges in the obstetric waiting areas were 23.8-28.6 degrees C and 18.5-23.5 degrees C, and acceptable standard effective temperature ranges were 21.0-27.9 degrees C and 19.0-25.8 degrees C during summer and winter, respectively. Further, the neutral temperature of pregnant women was lower than that of the males & non-pregnant female patients. The results of this study can guide the indoor thermal environments in the hospitals for the improved comfort of pregnant women, which in turn, will benefit their health as well as that of their babies.
期刊：
IET Image Processing,2021年15(1):155-165 ISSN：1751-9659
通讯作者：
Huang, Changjun
作者机构：
[Huang, Changjun; Zhou, Qingshan] Hunan City Univ, Sch Municipal & Surveying Engn, Yiyang 413000, Peoples R China.;[Huang, Changjun] Key Lab Key Technol Digital Urban Rural Spatial P, Yiyang 413000, Peoples R China.;[Zhou, Xinghua] Zhejiang Inst Hydraulice & Estuary, Hangzhou 310008, Peoples R China.;[Hu, Jiyuan] Wuhan Univ, Sch Geodesy & Geomat, Wuhan 430079, Peoples R China.
通讯机构：
[Huang, Changjun] H;Hunan City Univ, Sch Municipal & Surveying Engn, Yiyang 413000, Peoples R China.
关键词：
Optical, image and video signal processing;Radar equipment, systems and applications;Integral transforms;Principal component analysis
摘要：
In the process of synthetic aperture radar image noise suppression by the bi-dimensional empirical mode decomposition (BEMD) algorithm, the edge effect is a key problem in the BEMD operation. To weaken this effect, an improved BEMD-kernel principal component analysis (BEMD-KPCA) method of image denoising is proposed in this study. Experimental results show that the BEMDKPCA algorithm has a good capability of improving edge effects in the BEMD decomposition process and satisfying the requirement of the reliable decomposition results. Compared with the traditional BEMD method, the proposed approach has a good effect on suppressing speckle noise. Additionally, the denoised image from the decomposed components of the IMFs processed by the BEMD-KPCA method sufficiently preserves the edge and detail information, confirming its high coherency with the original image.
作者机构：
[Li, Tian; Chu, Huaqiang; Liu, Huachen; Dong, Bingzhi; Huang, Weipeng; Yu, Hongjian] Tongji Univ, Coll Environm Sci & Engn, Shanghai 200092, Peoples R China.;[Li, Tian; Chu, Huaqiang; Dong, Bingzhi] Tongji Univ, Minist Educ, Key Lab Yangtze River Water Environm, Shanghai 200092, Peoples R China.;[Li, Tian; Chu, Huaqiang; Dong, Bingzhi] Tongji Univ, State Key Lab Pollut Control & Resource Reuse, Shanghai 200092, Peoples R China.;[Chi, Nianping] Hunan City Univ, Sch Municipal & Geomat Engn, Yiyang 413000, Peoples R China.
通讯机构：
[Tian Li] C;College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China<&wdkj&>State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China<&wdkj&>Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai 200092, China<&wdkj&>Author to whom correspondence should be addressed.
摘要：
The combination of conventional and advanced water treatment is now widely used in drinking water treatment. However, membrane fouling is still the main obstacle to extend its application. In this study, the impact of the combination of coagulation and ultrafiltration (UF) membrane rotation on both fouling control and organic removal of macro (sodium alginate, SA) and micro organic matters (tannic acid, TA) was studied comprehensively to evaluate its applicability in drinking water treatment. The results indicated that membrane rotation could generate shear stress and vortex, thus effectively reducing membrane fouling of both SA and TA solutions, especially for macro SA organics. With additional coagulation, the membrane fouling could be further reduced through the aggregation of mediate and macro organic substances into flocs and elimination by membrane retention. For example, with the membrane rotation speed of 60 r/min, the permeate flux increased by 90% and the organic removal by 35% in SA solution, with 40 mg/L coagulant dosage, with an additional 70% increase of flux and 5% increment of organic removal to 80% obtained. However, too much shear stress could intensify the potential of fiber breakage at the potting, destroying the flocs and resulting in the reduction of permeate flux and deterioration of effluent quality. Finally, the combination of coagulation and membrane rotation would lead to the shaking of the cake layer, which is beneficial for fouling mitigation and prolongation of membrane filtration lifetime. This study provides useful information on applying the combined process of conventional coagulation and the hydrodynamic shear force for drinking water treatment, which can be further explored in the future.
作者机构：
[Li, Huan; Tian, Mao-Jun; Tamehe, Landry Soh] Cent South Univ, Sch Geosci & Info Phys, Minist Educ, Key Lab Metallogen Predict Nonferrous Met & Geol, Changsha 410083, Peoples R China.;[Xi, Zhen] Hunan City Univ, Sch Municipal & Geomat Engn, Yiyang 413000, Peoples R China.
通讯机构：
[Huan Li] K;Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring, Ministry of Education, School of Geosciences and Info-Physics, Central South University, Changsha 410083, China<&wdkj&>Author to whom correspondence should be addressed.
摘要：
The boundary between the Gondwana and Yangtze plate is still controversial. In southwest China, the Sanjiang region marks the collision zone which accreted several blocks coming from the northern Gondwana margin. In this region, subduction of the Paleo-Tethys Ocean and associated continental blocks during the Triassic Period led to the formation of an N-S trending complex involving intrusive and volcanic rocks. The intrusive rocks are important for constraining the evolution of the Paleo-Tethyan in southwestern China. This study presents new geochronological, geochemical, and Sr-Nd-Hf isotopic data of granite porphyries from northern Lancangjiang, in order to discuss the origin of these granites and their tectonic significance. Representative samples of the Zengudi and the Tuobake granite porphyries from the Yezhi area yielded weighted mean Pb-206/U-238 ages of 247-254 Ma and 246 Ma, respectively. The Zengudi granite porphyries display zircon (Hf)(t) values of -12.94 to -2.63, (Nd)(t) values of -14.5 to -9.35, and initial Sr-87/Sr-86 ratios of 0.708 to 0.716. The Tuobake granite porphyries have zircon (Hf)(t) values of -14.06 to -6.55, (Nd)(t) values of -10.9 to -9.41, and initial Sr-87/Sr-86 ratios of 0.716 to 0.731. Both the Zengudi and Tuobake granite porphyries exhibit strongly peraluminous signatures with high A/CNK nAl(2)O(3)/(K2O + Na2O + K2O) ratios (1.07-1.86 and 0.83-1.33, respectively). These granites are enriched in Rb and Th, and depleted in Ti, Nb, Ta, Sr, and P, with negative Eu anomalies (Eu/Eu* < 0.61). These geochemical and isotopic data indicate that the primary magma of the granite porphyries originated from partial melting of ancient continental crust as a result of basaltic magma underplating and underwent fractionation crystallization during their emplacement. We propose that the Triassic subduction of the Paleo-Tethys Ocean led to crust shortening and thickening in the Sanjiang region, while the northern Lancangjiang area was involved in the continental collision after the subduction of the Paleo-Tethys Ocean before 254 Ma.
作者机构：
[Zhong, Teng; Ye, Cheng; Wang, Zian; Tang, Guoan] Nanjing Normal Univ, Key Lab Virtual Geog Environm, Minist Educ, Nanjing 210023, Peoples R China.;[Zhong, Teng; Ye, Cheng; Wang, Zian; Tang, Guoan] Nanjing Normal Univ, State Key Lab Cultivat Base Geog Environm Evolut, Nanjing 210023, Peoples R China.;[Zhong, Teng; Ye, Cheng; Wang, Zian; Tang, Guoan] Nanjing Normal Univ, Jiangsu Ctr Collaborat Innovat Geog Informat Reso, Nanjing 210023, Peoples R China.;[Zhang, Wei] Cent South Univ, Sch Geosci & Infophys, Key Lab Metallogen Predict Nonferrous Met & Geol, Minist Educ, Changsha 410083, Peoples R China.;[Zhang, Wei] Hunan City Univ, Sch Municipal & Mapping Engn, Yiyang 413000, Peoples R China.
通讯机构：
[Wei Zhang] K;Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring (Ministry of Education), School of Geosciences and Info-Physics, Central South University, Changsha 410083, China<&wdkj&>School of Municipal and Mapping Engineering, Hunan City University, Yiyang 413000, China<&wdkj&>Author to whom correspondence should be addressed.
关键词：
urban color planning;urban façade color;street-view images;deep learning;Shenzhen
摘要：
Precise urban façade color is the foundation of urban color planning. Nevertheless, existing research on urban colors usually relies on manual sampling due to technical limitations, which brings challenges for evaluating urban façade color with the co-existence of city-scale and fine-grained resolution. In this study, we propose a deep learning-based approach for mapping the urban façade color using street-view imagery. The dominant color of the urban façade (DCUF) is adopted as an indicator to describe the urban façade color. A case study in Shenzhen was conducted to measure the urban façade color using Baidu Street View (BSV) panoramas, with city-scale mapping of the urban façade color in both irregular geographical units and regular grids. Shenzhen’s urban façade color has a gray tone with low chroma. The results demonstrate that the proposed method has a high level of accuracy for the extraction of the urban façade color. In short, this study contributes to the development of urban color planning by efficiently analyzing the urban façade color with higher levels of validity across city-scale areas. Insights into the mapping of the urban façade color from the humanistic perspective could facilitate higher quality urban space planning and design.
通讯机构：
[Yaoning Chen; Yuanping Li] C;College of Municipal and Mapping Engineering, Hunan City University, Yiyang, Hunan 413000, China<&wdkj&>College of Environmental Science and Engineering, Hunan University, Changsha 410082, China<&wdkj&>Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
摘要：
To reclaim and utilize wastepaper (WP), a WP/acrylamide double-network hydrogel (WP/PAM) was prepared to transform WP into efficient adsorbent for heavy metals and dye wastewater treatment. The structure and properties of the WP/PAM were characterized systematically by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), swelling performance (SR), Fourier transform infrared spectrum (FTIR), and X-ray photoelectron spectroscopy (XPS). Batch experiments showed that the adsorption process of Cu(ii) and MB followed the pseudo-second-order kinetic model and the Langmuir model. The maximum adsorption capacities of the WP/PAM for Cu(ii) and MB were 142.2 mg g(-1) and 1714.5 mg g(-1), respectively. The adsorption mechanism of Cu(ii) on the WP/PAM was related to ion exchange and complexation, while MB adsorption was driven by hydrogen bonding and electrostatic interaction. Besides, the WP/PAM performed well in treating simulated wastewater. The regeneration test indicated that the WP/PAM could be successfully reused after 6 cycles. This work provided an alternative choice for the recycling of WP and produced a potential adsorbent for the dye and heavy metals wastewater treatment.
通讯机构：
[Yaoning Chen] C;College of Environmental Science and Engineering, Hunan University, Changsha 410082, China<&wdkj&>Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China
作者机构：
[Long, Yue-hong; Zhu, Lei; Xue, Yun; Zhou, Song-lin] Hunan City Univ, Design Inst Co Ltd, Sch Municipal & Surveying Engn, Yiyang 413000, Peoples R China.;[Xue, Yun; Zou, Bin] Cent South Univ, Sch Geosci & Infophys, Key Lab Metallogen Predict Nonferrous Met & Geol, Changsha 410083, Peoples R China.;[Zhu, Lei] Jiangxi Univ Sci & Technol, Sch Civil & Surveying Engn, Ganzhou 341000, Peoples R China.;[Wen, Yi-min] Guilin Univ Elect Technol, Sch Comp Sci & Informat Secur, Guilin 541004, Peoples R China.
通讯机构：
[Zou, Bin] C;Cent South Univ, Sch Geosci & Infophys, Key Lab Metallogen Predict Nonferrous Met & Geol, Changsha 410083, Peoples R China.
关键词：
convolutional neural network;chlorophyll-a;Dongting Lake
摘要：
For Case-II water bodies with relatively complex water qualities, it is challenging to establish a chlorophyll-a concentration (Chl-a concentration) inversion model with strong applicability and high accuracy. Convolutional Neural Network (CNN) shows excellent performance in image target recognition and natural language processing. However, there little research exists on the inversion of Chl-a concentration in water using convolutional neural networks. Taking China's Dongting Lake as an example, 90 water samples and their spectra were collected in this study. Using eight combinations as independent variables and Chl-a concentration as the dependent variable, a CNN model was constructed to invert Chl-a concentration. The results showed that: (1) The CNN model of the original spectrum has a worse inversion effect than the CNN model of the preprocessed spectrum. The determination coefficient (R-P(2)) of the predicted sample is increased from 0.79 to 0.88, and the root mean square error (RMSEP) of the predicted sample is reduced from 0.61 to 0.49, indicating that preprocessing can significantly improve the inversion effect of the model.; (2) among the combined models, the CNN model with Baseline1_SC (strong correlation factor of 500-750 nm baseline) has the best effect, with R-P(2) reaching 0.90 and RMSEP only 0.45. The average inversion effect of the eight CNN models is better. The average R-P(2) reaches 0.86 and the RMSEP is only 0.52, indicating the feasibility of applying CNN to Chl-a concentration inversion modeling; (3) the performance of the CNN model (Baseline1_SC (R-P(2) = 0.90, RMSEP = 0.45)) was far better than the traditional model of the same combination, i.e., the linear regression model (R-P(2) = 0.61, RMSEP = 0.72) and partial least squares regression model (Baseline1_SC (R-P(2) = 0.58. RMSEP = 0.95)), indicating the superiority of the convolutional neural network inversion modeling of water body Chl-a concentration.
摘要：
Satellite-based mapping has been proven to be an effective method to reveal the spatiotemporal variations of PM2.5 distributions. However, most satellite AOD (aerosol optical depth) statistical models suffer from unstable accuracy over long time spans. This study thus aims to propose an accurate and stable method for PM2.5 concentration estimations in time series. Specifically, a three-step residual variance constraint method (RVCM) is developed to simulate PM2.5 concentrations from January 2013 to December 2017 with the aid of AODs and other auxiliary data. Results show that the five-year fitting R-2 and cross-validation R-2 of RVCMs improved from 0.77 to 0.88 and 0.71 to 0.84, respectively, compared to those models without residual variance constraint (WO-RVCM). Additionally, RVCM demonstrated more stable performance on time series simulation of PM2.5 concentrations than WO-RVCM, with the yearly fitting R-2 of 0.89, 0.88,0.85, 0.87 and 0.88, and corresponding cross validation R-2 of 0.85, 0.84, 0.80, 0.82 and 0.83, respectively. Furthermore, accuracy verification of removed outliers in residual variance constraint modeling confirmed the credibility of RVCM in outliers' simulation compared to WO-RVCM models. Finally, RVCM-aided estimations of time series PM2.5 concentrations and associated premature deaths in the study area (east and southeast mainland China) revealed their total decrease rates were 35.21% and 21.57%, and excellent air quality days increased from 7% to 35%. These findings suggest that residual variance constraint is effective and could be a reliable solution to providing time series AOD-PM(2.5 )modeling with stable accuracy over long time spans. (C) 2019 Elsevier B.V. All rights reserved.
摘要：
In this work, iron-manganese binary oxides (FMO) modified with different proportions of glucose addition (FMOCx) by co-precipitation method showed good activity in activating hydrogen peroxide (H2O2) for tetracycline degradation. The structure and surface characterizations of the FMO and FMOCx were measured by XRD, FTIR, TEM, BET and XPS. With increased glucose addition, FMOCx has more surface functional groups such as -OH and -COOH, particle size decreases, surface area gradually increases, and the ratio of high valence iron and manganese also increases. In addition, the glucose might be oxidized by KMnO4 to form amorphous carbon on the catalyst surface. Glucose modified iron-manganese binary oxides FMOC3 (with 0.003 mol glucose added) showed the highest efficiency removal capability for tetracycline up to 85%, which attribute to it has a larger surface area, more surface functional groups and higher surface active Mn(IV) site content. The results also demonstrated that FMOC3 could efficiently activate hydrogen peroxide. This study proves that glucose modified iron-manganese binary oxides (FMOCx) can offered a possibility of degradation of refractory organic pollutants as an environmentally friendly catalyst in the absence of H2O2 or not. (C) 2020 Elsevier Inc. All rights reserved.
摘要：
A metal-free environmentally-friendly and highly efficient photocatalyst is always desirable for photocatalytic remediation of antibiotic contamination. Herein, we firstly reported a novel g-C3N4/carbon dots nanosheets (C-CN-NS) nanocomposite photocatalyst which was prepared through a simple thermal oxidation etching process to remove a representative antibiotic sulfadiazine (SDZ). The degradation rate of SDZ by C-CN-NS500 (calcination temperature at 500 degrees C) was around 2.4 times larger than that of g-C3N4/carbon dots (C-CN) under visible light (lambda > 420 nm) irradiation. The valence band of C-CN-NS500 increased by 0.42 eV under the quantum confinement effect, which promoted the oxidation potential, in favor of the degradation of SDZ. Increased specific surface area, improved separation efficiency and prolonged contact time for C-CN-NS500 can also facilitate the degradation of SDZ. Experiments demonstrated that photo-induced hole (h(+)) has the strongest effect in photocatalytic degradation process, followed by O-center dot(2)-, and (OH)-O-center dot. The toxicity assessment showed that C-CN-NS500 nanocomposite has high biocompatibility and low toxicity. This work may provide a promising green photocatalyst for photocatalytic degradation of antibiotic contaminant.
摘要：
In recent years, water pollution has been attracted public attention being that its harm to human and ecology. Ferro-Manganese binary oxide (FMBO) with the characteristics of much active sites and high affinity to contaminants has been widely applied in wastewater treatment. This paper aims to review FMBO and its ramification, collectively named as FMBO-based materials to remove various pollutants from polluted water. Firstly, the synthesis methods of FMBO-based materials ware summarized and indicated that co-precipitation was the most common method. Secondly, the application of FMBO-based materials in water treatment was introduced emphatically. Thirdly, the influence factors refer to pH, coexisting ions and the physicochemical properties of FMBO-based materials ware also concluded. Moreover, the mechanisms including adsorption, redox and degradation were also discussed comprehensively and deeply. Finally, future researches on FMBO-based materials were also proposed such as toxicity of FMBO-based materials in practical environmental remediation, modifying potential waste by FMBO to realize the utilization of resources, composite catalytic system as to the synergistic mechanism, application in other refractory organic pollutants and application in soil remediation.
