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Enhancement of ultrasonic disintegration of sewage sludge by aeration

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Journal of environmental Sciences 2016年第4期28卷 163-167页

作者： He Zhao Panyue Zhang Guangming Zhang Rong Cheng School of environment and natural resource Renmin University of China College of environmental Science and Engineering Beijing Forestry University

Sonication is an effective way for sludge disintegration,which can significantly improve the efficiency of anaerobic digestion to reduce and recycle use of *** high energy consumption limits the wide application of *** order to improve ultrasonic sludge disintegration efficiency and reduce energy consumption,aeration was *** showed that sludge disintegration efficiency was improved significantly by combining aeration with *** aeration flow rate,gas bubble size,ultrasonic density and aeration timing had impacts on sludge disintegration *** that used in later stage of ultrasonic irradiation with low aeration flow rate,small gas bubbles significantly improved ultrasonic disintegration sludge *** the optimal conditions of 0.4 W/m L ultrasonic irradiation density,30 m L/min of aeration flow rate,5 min of aeration in later stage and small gas bubbles,ultrasonic sludge disintegration efficiency was increased by 45% and one third of ultrasonic energy was *** approach will greatly benefit the application of ultrasonic sludge disintegration and strongly promote the treatment and recycle of wastewater sludge.

关键词： Aeration Ultrasonic sludge disintegration Gas bubble size Ultrasonic irradiation density Ultrasonic irradiation stages

Modeling of acute cadmium toxicity in solution to barley root elongation using biotic ligand model theory

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Journal of environmental Sciences 2016年第4期28卷 112-118页

作者： Xuedong Wang Mingyan Wu Jingxing Ma Xiaolin Chen Luo Hua The Key Lab of resource environment and GIS College of Resource Environment and TourismCapital Normal University

Protons（H^＋）as well as different major and trace elements may inhibit cadmium（Cd）uptake in aquatic organisms and thus alleviate Cd ***,little is known about such interactions in soil *** this study,the independent effects of the cations calcium（Ca^2＋）,magnesium（Mg^2＋）,potassium（K^＋）,H^＋ and zinc（Zn^2＋）on Cd toxicity were investigated with 5-day long barley root elongation tests in nutrient *** tested concentrations of selected cations and trace metal ions were based on the ranges that occur naturally in soil pore *** toxicity of Cd decreased with increasing activity of Ca^2＋,Mg^2＋,H^＋and Zn^2＋,but not K^＋.Accordingly,conditional binding constants were obtained for the binding of Cd^2＋,Ca^2＋,Mg^2＋,H^＋,and Zn^2＋ with the binding ligand：log K（CdBL）5.19,logK（CaBL）2.87,logK（MgBL）2.98,logK（HBL）5.13 and logK（ZnBL）5.42,***,it was calculated that on average 29% of the biotic ligand sites needed to be occupied by Cd to induce a 50% decrease in root *** the estimated constants,a biotic ligand model was successfully developed to predict the Cd toxicity to barley root elongation as a function of solution *** feasibility and accuracy of its application for predicting Cd toxicity in soils were discussed.

关键词： Cadmium Biotic ligand model (BLM) Toxicity Barley

High potassium to magnesium ratio affected the growth and magnesium uptake of three tomato(Solanum lycopersicum L.) cultivars

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Journal of Integrative Agriculture 2018年第12期17卷 2813-2821页

作者： LI Hui-xia CHEN Zhu-jun ZHOU Ting LIU Yan ZHOU Jian-bin College of natural resource and environment Northwest A&F University Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China Ministry of Agriculture department of Bioengineering Yinchuan Institute of Energy

Potassium(K) and magnesium(Mg) levels and their balances are two factors affecting the growth of plant. However, the responses of different crop cultivars to K/Mg ratios are less clear. This study was aimed at assessing the different responses of tomato(Solanum Lycopersicum L.) cultivars to the different K/Mg supply ratios. Three tomato cultivars(Zhongza 9(ZZ), Gailiangmaofen(MF), and Jinpengchaoguan(JP)) were grown in pots with three different K+/Mg2+ratios(4:0, 4:1 and 8:1, represented by K/Mg4:0, K/Mg4:1, and K/Mg8:1, respectively). Compared with K/Mg4:1treatment, the leaf chlorophyll content, net photosynthetic rate, and total biomass of tomato seedlings under K/Mg4:0treatments were decreased by 69.7, 89.1, and 53.1%, respectively. The Mg deficiency symptoms were observed when the Mg content in shoot became lower than 4 mg g–1DW. Compared with K/Mg4:1treatment, total biomass of tomato seedlings of K/Mg8:1treatment was decreased by 21.6%; the shoot and root Mg contents were decreased by 10.4 and 21.8%, respectively; and Mg uptake of tomato was reduced by 34.1%. There were significant differences in biomass and Mg uptake for the three cultivars between the different K+/Mg2+treatments. The Mg uptake of the three different cultivars ranked as ZZ>JP>MF under Mg deficiency and high K condition. In conclusion, the growth and Mg uptake and allocation of tomato were influenced significantly by imbalance K and Mg supply. JP and ZZ were the cultivars with the highest efficiency in Mg uptake.

关键词： tomato cultivars potassium-magnesium ionic interaction magnesium uptake

MnCeOx/diatomite catalyst for persulfate activation to degrade organic pollutants

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Journal of environmental Sciences 2020年第3期32卷 206-217页

作者： Lijun Niu Guang Xian Zeqing Long Guangming Zhang Ningyu Zhou School of environment and natural resource Renmin University of ChinaBeijing 100872China department of Military Installations Army Lorange Gistics University of PLAChongqing 401311China

Persulfate(PS)-based oxidation technologies are attracting increasing attentions in water treatment due to their high efficiency and *** this study,a novel diatomite supported MnCeOx composite(MnCeOx/diatomite) was prepared and characterized for activation of PS to degrade organic *** indicated that diatomite not only dispersed MnCeOx and increased the specific surface area of catalyst,but also improved the low-valence metal site(Mn^2+and Ce^3+) and reactive oxygen species site(-OH) of MnCeOx,thus enhancing the activities of ***/diatomite/PS showed high efficiency for multiple dyes and pharmaceutical *** rate(k) of MnCeOx/diatomite(kMnCeOx/diatomite) was three times higher than the sum of constant rate of MnCeOx(kMnCeOx)and constant rate of diatomite(kdiatomite).In addition,MnCeOx/diatomite showed wide pH application(5-9).Cl^- and NO3^2- had no effect while SO4^2- and humid acid had slightly negative effects on MnCeOx/diatomite/PS ***,MnCeOx/diatomite showed good reusability and *** analyses indicated that electron transfer of Mn and Ce attributed to the activation of PS and oxygen to produce free ***4·^-,·OH and O2·^-on the surface of catalyst were the main active free radicals to attack pollutants.

关键词： MnCeOx/diatomite Persulfate Dyes and pharmaceutical pollutants Hydroxyl functional group

Assessment of highway slope failure using neural networks

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第1期10卷 101-108页

作者： Tsung-lin LEE Hung-ming LIN Yuh-pin LU 1department of Construction and Facility Management department of resource and environment Leader University

An artificial intelligence technique of back-propagation neural networks is used to assess the slope ***-site slope failure data from the South Cross-Island Highway in southern Taiwan are used to test the performance of the neural network *** numerical results demonstrate the effectiveness of artificial neural networks in the evaluation of slope failure potential based on five major factors,such as the slope gradient angle,the slope height,the cumulative precipitation,daily rainfall and strength of materials.

关键词： Neural network Prediction Highway Slope failure

Spatio-temporal changes of underground coal fires during 2008-2016 in Khanh Hoa coal field(North-east of Viet Nam) using Landsat time-series data

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Journal of Mountain Science 2018年第12期15卷 2703-2720页

作者： Tuyen Danh VU Thanh Tien NGUYEN department of Training Hanoi University of Natural Resources and Environment Faculty of Surveying Mapping and Geographic Information Hanoi University of Natural Resources and Environment

Underground coal fires are one of the most common and serious geohazards in most coal producing countries in the world. Monitoring their spatio-temporal changes plays an important role in controlling and preventing the effects of coal fires, and their environmental impact. In this study, the spatio-temporal changes of underground coal fires in Khanh Hoa coal field(North-East of Viet Nam) were analyzed using Landsat time-series data during the 2008-2016 period. Based on land surface temperatures retrieved from Landsat thermal data, underground coal fires related to thermal anomalies were identified using the MEDIAN+1.5×IQR(IQR: Interquartile range) threshold technique. The locations of underground coal fires were validated using a coal fire map produced by the field survey data and cross-validated using the daytime ASTER thermal infrared imagery. Based on the fires extracted from seven Landsat thermal imageries, the spatiotemporal changes of underground coal fire areas were analyzed. The results showed that the thermalanomalous zones have been correlated with known coal fires. Cross-validation of coal fires using ASTER TIR data showed a high consistency of 79.3%. The largest coal fire area of 184.6 hectares was detected in 2010, followed by 2014(181.1 hectares) and 2016(178.5 hectares). The smaller coal fire areas were extracted with areas of 133.6 and 152.5 hectares in 2011 and 2009 respectively. Underground coal fires were mainly detected in the northern and southern part, and tend to spread to north-west of the coal field.

关键词： Underground coal fires Spatio-temporal changes Khanh Hoa coal field (Viet Nam) Landsat time-series data

Mixed-effects modeling for tree height prediction models of Oriental beech in the Hyrcanian forests

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Journal of Forestry Research 2018年第5期29卷 1195-1204页

作者： Siavash Kalbi Asghar Fallah Pete Bettinger Shaban Shataee Rassoul Yousefpour Sari Agriculture and natural resource University SariMazandaran Iran Warnell School of Forestry and natural resources University of Georgia Athens GA USA Gorgan Agriculture and natural resource University Gorgan Golestan Iran Faculty of environment and natural resources University of Freiburg Freiburg Germany

Height–diameter relationships are essential elements of forest assessment and modeling *** this work,two linear and eighteen nonlinear height–diameter equations were evaluated to find a local model for Oriental beech（Fagus orientalis Lipsky） in the Hyrcanian Forest in *** predictive performance of these models was first assessed by different evaluation criteria： adjusted R^2（R^2_（adj））,root mean square error（RMSE）,relative RMSE（%RMSE）,bias,and relative bias（%bias） *** best model was selected for use as the base mixed-effects *** parameters for test plots were estimated with different tree selection *** show that the Chapman–Richards model had better predictive ability in terms of adj R^2（0.81）,RMSE（3.7 m）,%RMSE（12.9）,bias（0.8）,%Bias（2.79） than the other ***,the calibration response,based on a selection of four trees from the sample plots,resulted in a reduction percentage for bias and RMSE of about 1.6–2.7%.Our results indicate that the calibrated model produced the most accurate results.

关键词： Random effects Tree height Calibration Sangdeh forest Chapman–Richards model Oriental beech

Distribution and temporal variability of the solar resource at a site in south-east Norway

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Frontiers in Energy 2016年第4期10卷 375-381页

作者： Muyiwa S. ADARAMOLA department of Ecology and natural resource Management NorwegianUniversity of Life Sciences As 1430 Norway

Globally, solar energy is expected to play a significant role in the changing face of energy economies in the near future. However, the variability of this resource has been the main barrier for solar energy development in most locations around the world. This paper investigated the distribution and variability of solar radiation using the a 10-year （2006 to 2015） data collected at Sorhs meteor- ological station located at latitude 59° 39＇ N and longitude 10° 47＇E, about 93.3 m above sea level （about 30 km from Oslo）, in south-eastern part of Norway. It is found that on annual basis, the total number of days with a global solar radiation of less than 1 kWh/（m2.d） is 120 days while the total number of days with an expected global solar radiation greater than 3 kWh/（m2.d） is 156 days （42.74%） per year. The potential energy output from a horizontally placed solar collector in these 156 days is approximately 75% of the estimated annual energy output. In addition, it is found that the inter-annual coefficient of variation of the global solar radiation is 4.28%, while that of diffuse radiation is 4.96%.

关键词： coefficient of variation global solar radiation,diffuse ratio albedo PV energy systems

Constitutive model for casting magnesium alloy involving spherical void evolution

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中国有色金属学会会刊：英文版 2008年第A1期18卷 175-179页

作者：陈斌彭向和范镜泓孙士涛 department of Engineering Mechanics College of Resource and Environment ScienceChongqing University

Casting magnesium alloys are highly heterogeneous materials inevitably containing numerous *** voids will evolve during material deformation and markedly affect material behaviors,so it is important to investigate the equation of the void evolution and the constitutive relation involving the void *** assuming the voids in casting magnesium alloys were spherical,the growth equation of the voids was obtained from the incompressibility and continuity conditions of material matrix. Through combining the obtained void-growth equation with the void-nucleation equation relative to the increment of intrinsic-time measure,the evolution equation of the voids was *** introducing the presented void-evolution equation to a nonclassical elastoplastic constitutive equation,a constitutive model involving the void evolution was put *** corresponding numerical algorithm and finite element procedure of the model were developed and applied to the analysis of the elastoplastic response and the porosity change of casting magnesium alloy *** results show satisfactory agreement with those of the corresponding experiments.

关键词：镁合金压铸铸件饱和多孔介质