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Characterisation of the granular dynamics at the interface between a pipe and a granular flow in a rotating drum

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Particuology 2024年第3期86卷 117-125页

作者： Francois Rioual Paule Emmanuelle Eva Gbehe research unit FRISE National Research Institute for Agriculture Food and the Environment1 Rue Pierre Gilles De Gennes92160AntonyFrance

A new mobile bed heat exchanger is presented in this work which is composed of a flowing granular material in a rotating drum and a cylindrical pipe with potential interest in different energy applications as cooling,heating or heat recovery *** optimal design of the device requires a characterisation of the phenomena involved at the interface between the granular flow and the *** process is modelled by the discrete element method and a global classification of the flow patterns around the pipe is presented with respect to the three main control parameters of the problem:the Froude number,the diameter ratio and the relative filling height of the *** second part is devoted to the characterisation of the structure of the flow at the interface(velocity field,density field)in particular in a so-called Biflow regime where granular motion occurs above as well as below the pipe which is favourable to transfer by convection.A typical behavior at the interface with the pipe consists of a zone I with high velocities of particles at the top of the pipe,a second zone with quasistatic particles or low velocity particles at the front and at the bottom of the pipe and a last zone ll of depletion of particles at the back of the *** Froude number has a limited effect on the features of this structure on the first layer in the range of Froude numbers considered whereas the relative height is a more determinant parameter to control the relative magnitude of velocities in zone I and zone Il as well as the extent of the depletion *** first hydrodynamical characterisation can shed light on the dynamical regimes with improved transfer between the particles and the pipe boundary.

关键词： Granular flow Transfer Heat exchange Mobile bed Boundary condition

Effect of metal fractions on rice grain metal uptake and biological parameters in mica mines waste contaminated soils

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Journal of environmental Sciences 2024年第2期136卷 313-324页

作者： Saibal Ghosh Sandip Mondal Jajati Mandal Abhishek Mukherjee Pradip Bhattacharyya Agricultural and Ecological research unit Indian Statistical InstituteGiridihJharkhand 815301India School of Science Engineering&EnvironmentUniversity of SalfordManchester M54WTUK

Heavy metals from mica waste not only deteriorate the soil quality but also results in the uptake of metals in the *** present investigation was conducted to evaluate the effects of different fractions of metals on the uptake in rice,soil microbial and biochemical properties in mica waste-contaminated soils of Jharkhand,*** each active mine,soil samples were randomly collected at distances of100 m(zone 3).Sequential metal extraction was used to determine the fractions of different metals(nickel(Ni),cadmium(Cd),chromium(Cr)and lead(Pb))including water-soluble(Ws)and exchangeable metals(Ex),carbonate-bound metals(CBD),Fe/Mn oxide(OXD)bound metals,organically bound metals(ORG),and residues(RS).The Ni,Cr,Cd and Pb in rice grain were 0.83±0.41,0.41±0.19,0.21±0.14 and 0.17±0.08 mg/kg *** the variable importance plot of the random forest(RF)algorithm,the Ws fraction of Ni,Cr and Cd and Ex fraction of Pb was the most important predictor for rice grain metal ***,the partial dependence plots(PDP)give us an insight into the role of the two most important metal fractions on rice grain metal *** microbial and enzyme activity was significantly and negatively correlated with Ws and Ex metal fractions,indicating that water-soluble and exchangeable fractions exert a strong inhibitory effect on the soil microbiological parameters and enzyme activities.

关键词： Metal fractions Microbial parameters Mica waste soil Soil enzymes Rice Random forest

Time-sensitive prediction of NO_(2) concentration in China using an ensemble machine learning model from multi-source data

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Journal of environmental Sciences 2024年第3期137卷 30-40页

作者： Chenliang Tao Man Jia Guoqiang Wang Yuqiang Zhang Qingzhu Zhang Xianfeng Wang Qiao Wang Wenxing Wang Big Data research Center for Ecology and environment Environment Research InstituteShandong UniversityQingdao 266237China Shandong Provincial Eco-environment Monitoring Center Jinan 250101China

Nitrogen dioxide(NO_(2))poses a critical potential risk to environmental quality and public health.A reliable machine learning(ML)forecasting framework will be useful to provide valuable information to support government *** on the data from1609 air quality monitors across China from 2014-2020,this study designed an ensemble ML model by integrating multiple types of spatial-temporal variables and three sub-models for time-sensitive prediction over a wide *** ensemble ML model incorporates a residual connection to the gated recurrent unit(GRU)network and adopts the advantage of Transformer,extreme gradient boosting(XGBoost)and GRU with residual connection network,resulting in a 4.1%±1.0%lower root mean square error over XGBoost for the test *** ensemble model shows great prediction performance,with coefficient of determination of 0.91,0.86,and 0.77 for 1-hr,3-hr,and 24-hr averages for the test results,*** particular,this model has achieved excellent performance with low spatial uncertainty in Central,East,and North China,the major site-dense *** the interpretability analysis based on the Shapley value for different temporal resolutions,we found that the contribution of atmospheric chemical processes is more important for hourly predictions compared with the daily scale predictions,while the impact of meteorological conditions would be ever-prominent for the *** with existing models for different spatiotemporal scales,the present model can be implemented at any air quality monitoring station across China to facilitate achieving rapid and dependable forecast of NO_(2),which will help developing effective control policies.

关键词： Air quality prediction Deep learning Ensemble method Nitrogen dioxide Spatiotemporal covariates

From ore to MOF: A case of MIL-100(Fe) production from iron ore concentrates

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Progress in Natural Science:Materials International 2024年第1期34卷 66-73页

作者： Miao Chang Chiyao Tang Chong-Chen Wang Chen Zhao Beijing Key Laboratory of Functional Materials for Building Structure and environment Remediation School of Environment and Energy Engineering Beijing University of Civil Engineering and Architecture

Within this work, iron ore concentrates instead of elemental iron Fe0and iron salts like Fe（NO3）3and FeCl3were selected as iron source to prepare MIL-100（Fe）(labeled as MIL-100（Fe）-ore). The corresponding synthesis cost is reduced to half of the MIL-100（Fe） produced from elemental iron and iron salts. As well, the unreacted iron ore concentrates can be easily separated from the as-prepared MIL-100（Fe）-ore by magnetic to facilitate the purification process, free of the strong acids to wash the residual iron. The as-obtained MIL-100（Fe）-ore with Langmuir surface area up to 2281.6 m2g-1displayed long-term chemical stability. Furthermore, the sorption capacity of MIL-100（Fe）-ore towards malachite green（MG） is up to 522.3 mg g-1at 25℃ and initial pH = 3.2, higher than that of MIL-100（Fe） yielded by conventional hydrothermal process. Finally, the production cost and life cycle assessment of MIL-100（Fe）-ore were compared with other traditional production procedures. The results revealed that our work greatly reduced the synthesis cost and enhanced the environmental sustainability.

关键词： Metal-organic framework Iron ore concentrates Adsorption Life cycle assessment

Performance Enhancement of Single-Phase Immersion Liquid-Cooled Data Center Servers

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Journal of Thermal Science 2024年第5期33卷 1757-1772页

作者： GE Junlei XIA Feifan ZHANG Chengbin HUANG Yongping School of Energy and environment Southeast UniversityNanjing 210096China Wuhan Digital engineering research Institute Wuhan 430205China

As the promising cooling method for the next generation of data centers,the internal heat transport mechanism and enhancement mechanism of single-phase immersion liquid-cooled(SPILC)systems are not yet well *** address this,a steady-state three-dimensional numerical model is constructed herein to analyze flow and thermal transport capacities in servers using SPILC and traditional air-cooling ***,this paper emphasizes the influence of component positioning,and underscores the benefits of optimizing coolant flow distribution using *** results indicate that the SPILC system outperforms the traditional air-cooling approach at the same inlet Reynolds number(Re).When Re=10000,the SPILC method reduces the maximum temperature by up to 70.13%,increases the average convective heat transfer coefficient by287.5%,and provides better overall thermal uniformity in data center ***,placing devices downstream of high-power components creates"thermal barriers"and degrades thermal transport for upstream devices due to increased flow *** spacing between high-power devices can lead to the formation of bypass channels,further deteriorating heat ***,the addition of baffles in the inlet section of SPILC systems effectively enhances heat dissipation *** maximize the heat dissipation capacity,minimizing bypass channels and optimizing the flow distribution of coolants are crucial.

关键词： single-phase immersion liquid-cooled performance enhancement data center

Insights on selective Pb adsorption via O 2p orbit in UiO-66 containing rich-zirconium vacancies

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Chinese Chemical Letters 2024年第8期35卷 357-361页

作者： Yu-Hang Li Shuai Gao Lu Zhang Hanchun Chen Chong-Chen Wang Haodong Ji Eco-environment and Resource Efficiency research Laboratory School of Environment and EnergyPeking University Shenzhen Graduate SchoolShenzhen 518055China Beijing Key Laboratory of Functional Materials for Building Structure and environment Remediation School of Environment and Energy EngineeringBeijing University of Civil Engineering and ArchitectureBeijing 100044Chin

Herein,we constructed defective UiO-66 with rich Zr vacancy structure model,in which the defective structure was verified by various ***,the Pb adsorption experiments affirmed that defective UiO-66 could display better adsorption and selective adsorption ability than that of perfect *** results of partial density of states(PDOS)and Mulliken charge population indicated that the blue shift of O 2p and Zr 4d orbit induced the electron rearrangement of atoms closed to the bonding sites,while the positive charge number of Zr atoms decreased than *** with the expansion of pore size,Pb atom was more inclined to transfer and bond with unsaturated coordination *** significantly,quantitative structure-activity relationships(QSARs)demonstrated that selective capture of Pb instead of Zn,Cu,Cd and Hg displayed by defective UiO-66 was determined jointly by bond strength,adsorption energy and electron *** work provided some theoretical direction for the purpose of the fabrication of adsorbent and the investigation of mechanism.

关键词： Selective adsorption Heavy metal Density functional theory UiO-66 Zr vacancies

In-situ sludge reduction based on Mn^(2+)-catalytic ozonation conditioning:Feasibility study and microbial mechanisms

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Journal of environmental Sciences 2024年第1期135卷 185-197页

作者： Haozhe Huang Tingting Wei Hui Wang Bing Xue Sisi Chen Xiankai Wang Haibin Wu Bin Dong Zuxin Xu College of environmental Science and engineering Tongji UniversityShanghai 200092China YANGTZE Eco-environment engineering research Center China Three Gorges CorporationBeijing 100038China

To improve the sludge conditioning efficiency without increasing the ozone dose,an in-situ sludge reduction process based on Mn^(2+)-catalytic ozonation conditioning was *** ozone conditioning alone as a control,a lab-scale sequencing batch reactor coupled with ozonated sludge recycle was evaluated for its operating performance at an ozone dose of 75 mg O_(3)/g VSS and 1.5 mmol/L Mn^(2+)*** results showed a 39.4%reduction in MLSS and an observed sludge yield of 0.236 kg MLSS/kg COD for the O_(3)+Mn^(2+)group compared to the O_(3)group (15.3%and 0.292 kg MLSS/kg COD),accompanied by better COD,NH_(4)^(+)-N,TN and TP removal,improved effluent SS and limited impact on excess sludge ***,activity tests,BIOLOG ECO microplates and 16S rRNA sequencing were applied to elucidate the changing mechanisms of Mn^(2+)-catalytic ozonation related to microbial action:(1) Dehydrogenase activity reached a higher peak.(2) Microbial utilization of total carbon sources had an elevated effect,up to approximately 18%,and metabolic levels of six carbon sources were also increased,especially for sugars and amino acids most pronounced.(3) The abundance of Defluviicoccus under the phylum Proteobacteria was enhanced to 12.0%and dominated in the sludge,they had strong hydrolytic activity and metabolic *** bacteria of the genus Ferruginibacter also showed an abundance of 7.6%,they contributed to the solubilization and reduction of sludge *** results could guide researchers to further reduce ozonation conditioning costs,improve sludge management and provide theoretical support.

关键词： Activated sludge In-situ reduction Catalytic ozonation conditioning Dehydrogenase activity Carbon source utilization Microbial community

Self-templating synthesis of biomass-based porous carbon nanotubes for energy storage and catalytic degradation applications

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Green Energy & environment 2024年第3期9卷 584-595页

作者： Manman Xu Shiqi Fu Yukai Wen Wei Li Qiongfang Zhuo Haida Zhu Zhikeng Zheng Yuwen Chen Anqi Wang Kai Yan research Centre for Eco-environmental engineering School of Environment and Civil EngineeringDongguan University of TechnologyDongguan523808China School of environmental Science and engineering Sun Yat-sen UniversityGuangzhou510275China

Dwindling energy sources and a worsening environment are huge global problems,and biomass wastes are an under-exploited source of material for both energy and material ***,self-template decoction dregs of Ganoderma lucidum-derived porous carbon nanotubes(ST-DDLGCs)were synthesized via a facile and scalable strategy in response to these ***-DDLGCs exhibited a large surface area(1731.51 m^(2)g^(-1))and high pore volume(0.76 cm^(3)g^(-1)),due to the interlacing tubular structures of precursors and extra-hierarchical porous structures on tube *** the ST-DDLGC/PMS system,the degradation efficiency of capecitabine(CAP)reached~97.3%within 120 ***,ST-DDLGCs displayed high catalytic activity over a wide pH range of 3–9,and strong anti-interference to these typical and ubiquitous anions in wastewater and natural water bodies(i.e.,H_(2)PO_(4)^(-),NO_(3)^(-),Cl^(-) and HCO_(3)^(-)),in which a ^(1)O_(2)-dominated oxidation was identified and non-radical mechanisms were ***,ST-DDLGC-based coin-type symmetrical supercapacitors exhibited outstanding electrochemical performance,with specific capacitances of up to 328.1 F g^(-1)at 0.5 A g^(-1),and cycling stability of up to 98.6%after 10,000 cycles at a current density of 2 A g^(-1).The superior properties of ST-DDLGCs could be attributed to the unique porous tubular structure,which facilitated mass transfer and presented numerous active *** results highlight ST-DDLGCs as a potential candidate for constructing inexpensive and advanced environmentally functional materials and energy storage devices.

关键词： Ganoderma lucidum residue Porous carbon nanotubes Self-template method Wastewater treatment Supercapacitor electrode

High catalytic performance of neodymium modified Co_(3)O_(4) for toluene oxidation

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Journal of Rare Earths 2024年第1期42卷 94-101,I0004页

作者： Yanqiong Hu Luyue Zhang Jianbei Zhang Yongjun Liu School of Architecture and environment Sichuan UniversityChengdu610065China National engineering research Center for Flue Gas Desulfurization Chengdu610065China

Co-based catalysts are the most promising catalysts in catalytic oxidation of volatile organic compounds(VOCs).Precious metal doping is adopted to improve the catalytic activity of toluene on Co_(3)O_(4) catalysts,but greatly increases its cost along with *** is found that doping a small amount of rare earth(Ce,Pr,Sm and Nd)can dramatically promote the catalytic activity of Co_(3)O_(4).Especially,the Nd-doped Co_(3)O_(4) catalyst exhibits excellent catalytic activity with a toluene removal rate of 90% at 162.1℃,which is even better than that of Pt-doped Co_(3)O_(4).Compared with other rare earth metal doping,the Nd doping leads to a higher ratio of Co^(3+)/Co^(2+) and has more oxygen *** in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)experiments show that the lattice oxygen of Nd-Co sample can be utilized at a quite low temperature,while that of pure Co_(3)O_(4) cannot engage in oxidation reaction when the temperature is below 200℃,which visually demonstrates the main reason for the improved catalytic performance of Nd-Co catalyst.

关键词： Rare earth metals Nd Co_(3)O_(4) Toluene catalytic oxidation Oxygen vacancy Lattice oxygen