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A novel online analyzer for accurate and rapid measurement of volatile fatty acids in anaerobic wastewater treatment

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Journal of Environmental sciences 2022年第12期34卷 72-82页

作者： Qingshan Lin Yanchao Yuan Feixiang Zan Hui Lu Zongping Wang Gang Guo school of Environmental Science and engineering Huazhong University of Science and Technology(HUST)Key Laboratory of Water and Wastewater TreatmentMOHURDWuhan 430074China Department of Environmental Science and engineering Beijing University of Chemical TechnologyBeijing 100029China school of Environmental Science and engineering Sun Yat-sen UniversityGuangzhou 510275China

Volatile fatty acids(VFAs), which are largely generated during the anaerobic acidification process, are considered to be reliable indicators of the stable process operation. However,the common methods for monitoring VFAs are offline, and they are typically manual requiring time-consuming, costly and complex instruments. This study aims to develop a novel online analyzer for automatic measuring VFAs, which was based on the 5-p H point titration, embedded with a proportional-integral-derivative(PID) feedback control system. The results show that it can achieve accurate and rapid monitoring of VFAs ranging between 0-400 mg/L(<9 min/sample) but simultaneously faces the problems of overtitration and interference of complex characteristics of wastewater. In order to improve its accuracy and stability, the effects of three general coefficients(K_(I),K_(P), and K_(D)) of PID on the titration were investigated, and the optimal values of K_(I), K_(P), and K_(D)were found to be 1.5, 1.0, and-1.0~0.5,respectively. Besides, the initial titration speed was set at 0.06 m L/min, equal to the minimum speed of the peristaltic pump, and the dichotomy approach was integrated into the PID feedback controller. Owing to the above improvements, the relative mean deviation and standard deviation of measuring VFAs in both synthetic and real wastewaters were mostly lower than 5.0% and 5.0 mg/L, proving the online analyzer is rapid, accurate and reliable.

关键词： Volatile fatty acids Online analyzer 5-pH point titration PID feedback control Anaerobic process

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Year-round observation of atmospheric inorganic aerosols in urban Beijing:Size distribution,source analysis,and reduction mechanism

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Journal of Environmental sciences 2022年第4期34卷 354-364页

作者： Xi Zhang Jinhe Wang Kai Zhang Xiaona Shang Masahide Aikawa Guanhua Zhou Jie Li Huanhuan Li State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China Resources and Environment Innovation Research Institute School of Municipal and Environmental EngineeringShandong Jianzhu UniversityJinan 250101China Faculty of Environmental engineering The University of Kitakyushu1-1 HibikinoWakamatsuKitakyushuFukuoka 808-0135Japan school of Instrumentation Science and Opto-electronics engineering Beihang UniversityBeijing 100191China Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention(LAP3) Department of Environmental Science and EngineeringFudan UniversityShanghai 200438China

To investigate particle characteristics and find an effective measure to control severe particle pollution,year-round observation of size-segregated inorganic aerosols was conducted in Beijing fromJanuary to December,2016.The sampled atmospheric particles all presented bimodal size distribution at four pollution levels(clear,slight pollution,moderate pollution and severe pollution),and peak values appeared at the size range of 0.7-2.1μmand>9.0μm,respectively.As dominant particle compositions,NO_(3)^(-),SO_(4)^(2-),and NH_(4)^(+)in four pollution levels all showed significant peaks in fine mode,especially at the size range of 1.1-2.1μm.Secondary inorganic aerosols accounted for about 67.6%(36.3%(secondary sulfates)+31.3%(secondary nitrates))of the total sources of fine particles in urban Beijing.Severe pollution of fine particles was mainly caused by the air masses transported from nearby western and southern areas,which are industrial and densely populated region,respectively.Sensitivity tests further revealed that the control measures focusing on ammonium emission reduction was the most effective for particle pollution mitigation,and fine particles all showed nonlinear responses after reducing ammonium,nitrate,and sulfate concentrations,with the fitting curves of y=-120.8x-306.1x^(2)+290.2x^(3),y=-43.5x-67.8x^(2),and y=-25.8x-110.4x^(2)+7.6x^(3),respectively(y and x present fine particle mass variation(μg/m3)and concentration reduction ratio(CRR)/100(dimensionless)).Overall,our study presents useful information for understanding the characteristics of atmospheric inorganic aerosols in urban Beijing,as well as offers policy makers with effective measure for mitigating particle pollution.

关键词： Size distribution Secondary inorganic ions Source analysis Secondary formation Sensitivity test

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Dual single-atom Ce-Ti/MnO_(2)catalyst enhances low-temperature NH_(3)-SCR performance with high H_(2)O and SO_(2)resistance

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Nano Research 2023年第1期16卷 299-308页

作者： Jingjing Song Shaomian Liu Yongjun Ji Wenqing Xu Jian Yu Bing Liu Wenxing Chen Jianling Zhang Lihua Jia Tingyu Zhu Ziyi Zhong Guangwen Xu Fabing Su College of Chemistry and Chemical engineering Qiqihaer UniversityQiqihaer 161006China Institute of Process engineering Chinese Academy of SciencesBeijing 100190China school of Light Industry Beijing Technology and Business UniversityBeijing 100048China Department of Chemical engineering School of Chemical and Material EngineeringJiangnan UniversityWuxi 214122China school of Materials Science and engineering Beijing Institute of TechnologyBeijing 100081China Department of Chemical engineering Guangdong Technion-Israel Institute of Technology(GTIIT)Shantou 515063China Technion-Israel Institute of Technology(IIT) Haifa 32000Israel Institute of Industrial Chemistry and Energy Technology Shenyang University of Chemical TechnologyShenyang 110142China

Mn-based catalysts have exhibited promising performance in low-temperature selective catalytic reduction of NOx with NH_(3)(NH_(3)-SCR).However,challenges such as H_(2)O-or SO_(2)-induced poisoning to these catalysts still remain.Herein,we report an efficient strategy to prepare the dual single-atom Ce-Ti/MnO_(2)catalyst via ball-milling and calcination processes to address these issues.Ce-Ti/MnO_(2)showed better catalytic performance with a higher NO conversion and enhanced H_(2)O-and SO_(2)-resistance at a lowtemperature window(100−150°C)than the MnO_(2),single-atom Ce/MnO_(2),and Ti/MnO_(2)catalysts.The in situ infrared Fourier transform spectroscopy analysis confirmed there is no competitive adsorption between NOx and H_(2)O over the Ce-Ti/MnO_(2)catalyst.The calculation results showed that the synergistic interaction of the neighboring Ce-Ti dual atoms as sacrificial sites weakens the ability of the active Mn sites for binding SO_(2)and H_(2)O but enhances their binding to NH_(3).The insight obtained in this work deepens the understanding of catalysis for NH_(3)-SCR.The synthesis strategy developed in this work is easily scaled up to commercialization and applicable to preparing other MnO_(2)-based single-atom catalysts.

关键词： dual single atom catalyst Ce-Ti/MnO_(2) selective catalytic reduction of NOx with NH_(3)(NH_(3)-SCR) low-temperature performance H_(2)O-and SO_(2)-resistance

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Resolving Mixed Intermediate Phases in Methylammonium-Free Sn-Pb Alloyed Perovskites for High-Performance Solar Cells

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Nano-Micro Letters 2022年第10期14卷 178-196页

作者： Zhanfei Zhang Jianghu Liang Jianli Wang Yiting Zheng Xueyun Wu Congcong Tian Anxin Sun Zhenhua Chen Chun-Chao Chen school of Materials Science and engineering Shanghai Jiao Tong UniversityShanghai 20024People’s Republic of China Shanghai Synchrotron Radiation Facility(SSRF) Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201800People’s Republic of China

The complete elimination of methylammonium(MA)cations in Sn-Pb composites can extend their light and thermal stabilities.Unfortunately,MA-free Sn-Pb alloyed perovskite thin films suffer from wrinkled surfaces and poor crystallization,due to the coexistence of mixed intermediate phases.Here,we report an additive strategy for finely regulating the impurities in the intermediate phase of Cs_(0.25)FA_(0.75)Pb_(0.6)Sn_(0.4)I_(3)and,thereby,obtaining high-performance solar cells.We introduced d-homoserine lactone hydrochloride(D-HLH)to form hydrogen bonds and strong Pb-O/Sn-O bonds with perovskite precursors,thereby weakening the incomplete complexation effect between polar aprotic solvents(e.g.,DMSO)and organic(FAI)or inorganic(CsI,PbI_(2),and SnI_(2))components,and balancing their nucleation processes.This treatment completely transformed mixed intermediate phases into pure preformed perovskite nuclei prior to thermal anneal-ing.Besides,this D-HLH substantially inhibited the oxidation of Sn^(2+) species.This strategy generated a record efficiency of 21.61%,with a Voc of 0.88 V for an MA-free Sn-Pb device,and an efficiency of 23.82%for its tandem device.The unencapsulated devices displayed impressive thermal stability at 85℃ for 300 h and much improved continuous operation stability at MPP for 120 h.

关键词： Intermediate phase Homogeneous nucleation process MA-free tin-lead alloyed perovskite Light and thermal stability Tandem device

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The greenhouse gas budget for China's terrestrial ecosystems

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National Science Review 2023年第12期10卷 55-57页

作者： Xuhui Wang Yuanyi Gao Kai Wang Yuxing Sang Yilong Wang Yuzhong Zhang Songbai Hong Yao Zhang Wenping Yuan Institute of Carbon Neutrality Sino-French Institute for Earth System Science College of Urban and Environmental Sciences Peking University State Key Laboratory of Tibetan Plateau Earth System Resources and Environment(TPESRE) Institute of Tibetan Plateau ResearchChinese Academy of Sciences Key Laboratory of Coastal Environment and Resources of Zhejiang Province School of EngineeringWestlake University Institute of Advanced Technology Westlake Institute for Advanced Study school of Atmospheric sciences Sun Yat-sen University

The increased atmospheric concentrations of greenhouse gases (GHGs,including CO2, CH4 and N2O) are unequivocally the major driving forces of climate warming [1]. These GHGs originate not only from the use of fossil fuels, but also from disturbances to and management of terrestrial ecosystems.Recent evidence suggests that terrestrial ecosystems,

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Spatial and Temporal Stress Variations before and after the 2008 Wenchuan M_(w)7.9 Earthquake and its Implications:A Study based on Borehole Stress Data

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Acta Geologica Sinica(English Edition) 2023年第1期97卷 226-242页

作者： MENG Wen LIN Weiren CHEN Qunce LI Yonghua Institute of Geophysics China Earthquake AdministrationBeijing 100081China Key Laboratory of Earthquake Source Physics China Earthquake AdministrationBeijing 100081China Key Laboratory of Active Tectonics and Geological Safety Ministry of Natural ResourcesInstitute of GeomechanicsChinese Academy of Geological SciencesBeijing 100081China graduate school of engineering Kyoto UniversityKyotoJapan

In situ stress measurement data was analyzed to estimate the temporal and spatial stress variations at shallow depths in the Longmenshan fault zone(LMSF),prior to and following the 2008 Wenchuan earthquake(WCEQ).Analysis of the stress field related to fault strength and behavior is useful for understanding geodynamic processes and conducting hazard assessments.The shallow stress changes after the WCEQ show clear along-strike variations.Degrees of stress orientation rotations have a negative correlation with the horizontal principal stress ratios and the WCEQ apparently reduced the magnitude difference between horizontal principal stresses.Taking stress magnitudes and orientation distribution relative to the fault strike into account,we propose an intermediate-strength of LMSF,with a friction coefficient generally constrained between 0.35 and 0.6.In addition,high-pressure fluids in the fault zone reduce the effective normal stress and to a certain degree weaken the fault strength.The accumulated stress over a certain period following release of the WCEQ indicates the start of another earthquake cycle.The changing crustal stress field makes the LMSF stable or slipping optimally during geodynamic processes.The segmentation feature of the shallow crustal stress field in the LMSF may imply a different tectonic loading and seismic release processes along the fault.The southwestern section to the epicenter of the WCEQ favors the occurrence of future earthquakes,as highμm in a state of critical failure was present in this area,which indicates that the Wenchuan and Lushan earthquakes did not release the accumulated stress to a sufficient extent there.

关键词： stress variation in situ stress measurement fault strength hazard assessment Longmenshan fault zone

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Systematical analysis of sludge treatment and disposal technologies for carbon footprint reduction

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Journal of Environmental sciences 2023年第6期128卷 224-249页

作者： Yingxin Zhao Zhifan Yang Jiaojiao Niu Zihan Du Conti Federica Zhe Zhu Kaichao Yang Yan Li Baofeng Zhao Thomas Helmer Pedersen Chunguang Liu Mutabazi Emmanuel school of Environmental Science and engineering Tianjin UniversityTianjin 300350China Tianjin Municipal engineering Design&Research Institute Co. Ltd.Tianjin 300380China Tianjin International engineering Institute Tianjin UniversityTianjin 300072China Department of Energy Technology Aalborg UniversityAalborg 9220Denmark school of Environmental Science and Safety engineering Tianjin University of TechnologyTianjin 300384China Energy Research Institute of Shandong Academy of sciences Jinan 250014China Shandong Kailin environmental protection equipment Co. Ltd.Heze 274000China

This study aims to comprehensively analyze the Greenhouse Gases(GHGs)emissions from current sewage sludge treatment and disposal technologies(buildingmaterial,landfill,land spreading,anaerobic digestion,and thermochemical processes)based on the database of Science Citation Index(SCI)and Social Science Citation Index(SSCI)from 1998 to 2020.The general patterns,spatial distribution,and hotspotswere provided by bibliometric analysis.A comparative quantitative analysis based on life cycle assessment(LCA)put forward the current emission situation and the key influencing factors of different technologies.The effective GHG emissions reduction methods were proposed to mitigate climate change.Results showed that incineration or building materials manufacturing of highly dewatered sludge,and land spreading after anaerobic digestion have the best GHG emissions reduction benefits.Biological treatment technologies and thermochemical processes have great potential for reducing GHGs.Enhancement of pretreatment effect,co-digestion,and newtechnologies(e.g.,injection of carbon dioxide,directional acidification)are major approaches to facilitate substitution emissions in sludge anaerobic digestion.The relationship between the quality and efficiency of secondary energy in thermochemical process and GHGs emission still needs further study.Solid sludge products generated by bio-stabilization or thermochemical processes are considered to have a certain carbon sequestration value and can improve the soil environment to control GHG emissions.The findings are useful for future development and processes selection of sludge treatment and disposal facing carbon footprint reduction.

关键词： Bibliometrics Sewage sludge Greenhouse gas Life cycle assessment Sludge management

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A regression model-based method for indoor positioning with compound location fingerprints

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Geo-Spatial Information Science 2019年第2期22卷 107-113,I0003页

作者： Tomofumi Takayama Takeshi Umezawa Nobuyoshi Komuro Noritaka Osawa Hewlett-Packard Japan LtdTokyoJapan graduate school of engineering Chiba UniversityChibaJapan

This paper proposed and evaluated an estimation method for indoor positioning.The method combines location fingerprinting and dead reckoning differently from the conventional combinations.It uses compound location fingerprints,which are composed of radio fingerprints at multiple points of time,that is,at multiple positions,and displacements between them estimated by dead reckoning.To avoid errors accumulated from dead reckoning,the method uses short-range dead reckoning.The method was evaluated using 16 Bluetooth beacons installed in a student room with the dimensions of 11×5 m with furniture inside.The Received Signal Strength Indicator(RSSI)values of the beacons were collected at 30 measuring points,which were points at the intersections on a 1×1 m grid with no obstacles.A compound location fingerprint is composed of RSSI vectors at two points and a displacement vector between them.Random Forests(RF)was used to build regression models to estimate positions from location fingerprints.The root mean square error of position estimation was 0.87 m using 16 Bluetooth beacons.This error is lower than that received with a single-point baseline model,where a feature vector is composed of only RSSI values at one location.The results suggest that the proposed method is effective for indoor positioning.

关键词： Indoor positioning integrated estimation radio fingerprinting dead reckoning machine learning non-linear regression

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An Improved Ensemble Learning Approach for Heart Disease Prediction Using Boosting Algorithms

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Computer Systems Science & engineering 2023年第9期46卷 3993-4006页

作者： ShahidMohammad Ganie Pijush Kanti Dutta Pramanik Majid BashirMalik Anand Nayyar Kyung Sup Kwak school of Business Woxsen UniversityHyderabadTelangana502345India school of Computing Science&engineering Galgotias UniversityGreater NoidaUP 203201India Department of Computer sciences Baba Ghulam Shah Badshah UniversityRajouri185234India graduate school Faculty of Information TechnologyDuy Tan UniversityDa Nang50000Vietnam Department of Information and Communication engineering Inha University22212Korea

Cardiovascular disease is among the top five fatal diseases that affect lives worldwide.Therefore,its early prediction and detection are crucial,allowing one to take proper and necessary measures at earlier stages.Machine learning(ML)techniques are used to assist healthcare providers in better diagnosing heart disease.This study employed three boosting algorithms,namely,gradient boost,XGBoost,and AdaBoost,to predict heart disease.The dataset contained heart disease-related clinical features and was sourced from the publicly available UCI ML repository.Exploratory data analysis is performed to find the characteristics of data samples about descriptive and inferential statistics.Specifically,it was carried out to identify and replace outliers using the interquartile range and detect and replace the missing values using the imputation method.Results were recorded before and after the data preprocessing techniques were applied.Out of all the algorithms,gradient boosting achieved the highest accuracy rate of 92.20%for the proposed model.The proposed model yielded better results with gradient boosting in terms of precision,recall,and f1-score.It attained better prediction performance than the existing works and can be used for other diseases that share common features using transfer learning.

关键词： Heart disease prediction machine learning classifiers ensemble approach XGBoost AdaBoost gradient boost

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Characteristics of air-water upward intermittent flows with surfactant additive in a pipeline-riser system

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Journal of Hydrodynamics 2018年第2期30卷 287-295页

作者：高梦忱许晶禹 Institute of Mechanics Chinese Academy of Sciences school of engineering sciences University of Chinese Academy of Sciences

The effect of the surfactant additive on the upward intermittent flows in a pipeline-riser system is studied experimentally, in a 3 m long horizontal pipe connected to a Perspex pipe of 2.0 m long and 25 mm in diameter, inclined to the horizontal plane by 7？, followed by the vertical PVC riser of 3.5 m high and 25 mm in diameter, operating at the atmospheric end pressure. Based on the analysis of the pressure signal and the visual observation of the riser, it is shown that the additive of surfactant to the carrying liquid makes bubbles smaller in size but much larger in number in the upward intermittent flows. In addition, the additive of surfactant to a two-phase flow does not have a significant impact on the in-situ gas fraction, the pressure drop and the frequency of the liquid slug, but it reduces significantly the velocity of the liquid slug. When the superficial liquid velocity is set, an exponential relationship between the dimensionless velocity of the liquid slug and the Webber number can be obtained. These results might be used for estimating the characteristic parameters of the upward intermittent flow based upon the input operating conditions.

关键词： Upward intermittent flow pipeline-riser system surfactant additive

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