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Inherent relations between yield stress and stability of bubble petroleum coke water slurry

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Petroleum Science 2018年第1期15卷 157-163页

作者： Fu-Yan Gao eric j.hu Ningbo Institute of Technology Zhejiang University School of Mechanical Engineering The University of Adelaide

The stability of petroleum coke water slurry（PCWS） is currently a hot topic. The inherent relationship between yield stress and stability of bubble-PCWS was studied through orthogonal experiments and range analysis in this work. The results showed that the stability of bubble-PCWS was positively related to the yield stress and that the yield stress could be greatly impacted by the operation conditions during preparation of bubble-PCWS. The main factors affecting the yield stress of bubble-PCWS were solid concentration, aeration time and dosage of frother. However, the effects of aperture size of air distribution plates and type of frother on the yield stress were slight within the experimental range. The optimal conditions for the greatest yield stress were as follows： aeration time of 30 min, solid concentration of 65 wt%, frother dosage of0.030 wt% of the air-dried pulverized petroleum coke, aperture size of air distribution plate of 2-5 lm and AOS *** yield stress and the pour rate of bubble-PCWS under this optimum operation condition could reach maxima of more than 0.4 Pa and 96%, respectively.

关键词： Petroleum coke Petroleum coke water slurry (PCWS) Stability Yield stress Orthogonal experiment

GraphFlow+:Exploiting Conversation Flow in Conversational Machine Comprehension with Graph Neural Networks

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Machine Intelligence Research 2024年第2期21卷 272-282页

作者： jing hu Lingfei Wu Yu Chen Po hu Mohammed j.Zaki School of Computer Science Central China Normal UniversityWuhan 430079China Pinterest San Francisco 94016USA Meta Mountain View 94039USA Rensselaer Polytechnic Institute Troy 12180USA

The conversation machine comprehension(MC)task aims to answer questions in the multi-turn conversation for a single ***,recent approaches don’t exploit information from historical conversations effectively,which results in some references and ellipsis in the current question cannot be *** addition,these methods do not consider the rich semantic relationships between words when reasoning about the passage *** this paper,we propose a novel model GraphFlow+,which constructs a context graph for each conversation turn and uses a unique recurrent graph neural network(GNN)to model the temporal dependencies between the context graphs of each ***,we exploit three different ways to construct text graphs,including the dynamic graph,static graph,and hybrid graph that combines the *** experiments on CoQA,QuAC and DoQA show that the GraphFlow+model can outperform the state-of-the-art approaches.

关键词： Conversational machine comprehension(MC) reading comprehension question answering graph neural networks(GNNs) natural language processing(NLP)

Deep learning automation of radiographic patterns for hallux valgus diagnosis

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World journal of Orthopedics 2024年第2期15卷 105-109页

作者： Angela hussain Cadence Lee eric hu Farid Amirouche Department of Orthopaedic Surgery University of Illinois College of MedicineChicagoIL 60612United States Department of Orthopaedics Surgery University of Illinois at ChicagoChicagoIL 60612United States Department of Orthopaedic Surgery Northshore University Health SystemSkokieIL 6007United States

Artificial intelligence(AI)and deep learning are becoming increasingly powerful tools in diagnostic and radiographic *** learning has already been utilized for automated detection of pneumonia from chest radiographs,diabetic retinopathy,breast cancer,skin carcinoma classification,and metastatic lymphadenopathy detection,with diagnostic reliability akin to medical *** the World journal of Orthopedics article,the authors apply an automated and AIassisted technique to determine the hallux valgus angle(HVA)for assessing HV foot *** the U-net neural network,the authors constructed an algorithm for pattern recognition of HV foot deformity from anteroposterior highresolution *** performance of the deep learning algorithm was compared to expert clinician manual performance and assessed alongside clinician-clinician *** authors found that the AI tool was sufficient in assessing HVA and proposed the system as an instrument to augment clinical *** further sophistication is needed to establish automated algorithms for more complicated foot pathologies,this work adds to the growing evidence supporting AI as a powerful diagnostic tool.

关键词： Artificial intelligence Hallux valgus Deep learning Automated radiography

Optimization of chemistry and process parameters for control of intermetallic formation in Mg sludges

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journal of Magnesium and Alloys 2024年第4期12卷 1431-1448页

作者： Y.Fu G.G.Wang A.hu Y.Li K.B.Thacker j.P.Weiler H.hu Department of Mechanical Automotive and Materials EngineeringUniversity of Windsor401 Sunset AveWindsorOntario N9B 3P4Canada Global Technology Centre Meridian Lightweight Technologies25 MacNab AveStrathroyOntario N7G 4H6Canada

Intermetallic formation in sludge during magnesium(Mg)melting,holding and high pressure die casting practices is a very important ***,very often it is overlooked by academia,original equipment manufacturers(OEM),metal ingot producers and even die *** aim of this study was to minimize the intermetallic formation in Mg sludge via the optimization of the chemistry and process *** Al8Mn5 intermetallic particles were identified by the microstructure analysis based on the Al and Mn *** design of experiment(DOE)technique,Taguchi method,was employed to minimize the intermetallic formation in the sludge of Mg alloys with various chemical compositions of Al,Mn,Fe,and different process parameters,holding temperature and holding *** sludge yield(SY)and intermetallic size(IS)was selected as two *** optimum combination of the levels in terms of minimizing the intermetallic formation were 9 wt.%Al,0.15 wt.%Mn,0.001 wt.%(10 ppm)Fe,690℃ for the holding temperature and holding at 30 mins for the holding time,*** best combination for smallest intermetallic size were 9 wt.%Al,0.15 wt.%Mn,0.001 wt.%(10 ppm)Fe,630℃ for the holding temperature and holding at 60 mins for the holding time,*** groups of sludge factors,Chemical Sludge(CSF),Physical Sludge(PSF)and Comprehensive Sludge Factors(and CPSF)were established for prediction of sludge yields and intermetallic sizes in Al-containing Mg *** CPSF with five independent variables including both chemical elements and process parameters gave high accuracy in prediction,as the prediction of the PSF with only the two processing parameters of the melt holding temperature and time showed a relatively large deviation from the experimental *** Chemical Sludge Factor was primarily designed for small ingot producers and die casters with a limited melting and holding capacity,of which process parameters could be fixed *** Physical Sludge Factor could be used f

关键词： Magnesium sludge Al-Mn intermetallic Optimization Taguchi method Sludge factor Chemical composition Process parameter

Theoretical and experimental study of a bi-stable piezoelectric energy harvester under hybrid galloping and band-limited random excitations

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 461-478页

作者： Haitao LI Tianyu ZHENG Weiyang QIN Ruilan TIAN hu DING j.C.jI Liqun CHEN Department of Engineering Mechanics North University of ChinaTaiyuan 030051China Department of Engineering Mechanics Northwestern Polytechnical UniversityXi'an 710072China Department of Engineering Mechanics Shijiazhuang Tiedao UniversityShijiazhuang 050043China Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Frontier Science Center of MechnoinformaticsShanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China School of Mechanical and Mechatronic Engineering University of Technology SydneyNew South Wales 2007Australia

In the practical environment,it is very common for the simultaneous occurrence of base excitation and *** the combined energy of vibration and wind with a single energy harvesting structure is *** this purpose,the effects of the wind speed and random excitation level are investigated with the stochastic averaging method(SAM)based on the energy *** results of the analytical prediction are verified with the Monte-Carlo method(MCM).The numerical simulation shows that the introduction of wind can reduce the critical excitation level for triggering an inter-well jump and make a bi-stable energy harvester(BEH)realize the performance enhancement for a weak base ***,as the strength of the wind increases to a particular level,the influence of the random base excitation on the dynamic responses is weakened,and the system exhibits a periodic galloping response.A comparison between a BEH and a linear energy harvester(LEH)indicates that the BEH demonstrates inferior performance for high-speed *** experiments are conducted to investigate the validity of the theoretical prediction and numerical *** experimental findings also show that strong random excitation is favorable for the BEH in the range of low wind ***,as the speed of the incoming wind is up to a particular level,the disadvantage of the BEH becomes clear and evident.

关键词： bi-stability inter-well response galloping band-limited random

Effects of different organic fertilizers on nitrous oxide and methane emissions from double-cropping rice fields

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Pedosphere 2024年第1期34卷 52-62页

作者： Mingcheng hu Andrew j.WADE Weishou SHEN Zhenfang ZHONG Chongwen QIU Xiangui LIN jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Collaborative Innovation Center of Atmospheric Environment and Equipment TechnologySchool of Environmental Science and EngineeringNanjing University of Information Science&TechnologyNanjing 210044China Department of Geography and Environmental Science University of ReadingReading RG66 DWUK Haina Research Institute of Guangdong Haina Agricultural Co. Ltd.Huizhou 516000China State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China

Rice fields are a major source of greenhouse gases,such as nitrous oxide (N_(2)O) and methane (CH_(4)).Organic fertilizers may potentially replace inorganic fertilizers to meet the nitrogen requirement for rice growth;however,the simultaneous effects of organic fertilizers on N_(2)O and CH_(4)emissions and crop yield in paddy fields remain poorly understood and *** this study,experimental plots were established in conventional double-cropping paddy fields in the Pearl River Delta,China,including an unfertilized control and five fertilizer treatments with fresh organic fertilizer (FOF),successively composted organic fertilizer (SOF),chemically composted organic fertilizer (COF),COF supplemented with inorganic fertilizer (COIF),and chemical fertilizers (CFs)(TFOF,TSOF,TCOF,TCOIF,and TCF,respectively).Paddy field soils behaved simultaneously as an N_(2)O sink (cumulative N_(2)O emission:-196 to-381 g N ha^(-1)) and as a CH_(4)source (cumulative CH_(4)emission:719 to 2 178 kg ha^(-1)).Compared to CFs,the effects of organic fertilizers on N_(2)O emission were not *** contrast,total annual CH_(4)emission increased by 157%,132%,125%,and 37%in TFOF,TCOF,TSOF,and TCOIF,respectively,compared to *** TCOIF,rice yield was maintained,while CH_(4)emission was not significantly increased from the paddy fields characterized by a prolonged flood *** important next step is to extend these field-based measurements to larger rice cultivation areas to quantify the regional and national-scale impacts on greenhouse gas emissions and to help determine the optimum practice for fertilizer use.

关键词： crop production global warming potential greenhouse gases manure paddy sustainable agriculture

Constrained re-calibration of two-equation Reynolds-averaged Navier–Stokes models

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Theoretical & Applied Mechanics Letters 2024年第2期14卷 82-89页

作者： Yuanwei Bin Xiaohan hu jiaqi Li Samuel j.Grauer Xiang I.A.Yang Department of Mechanical Engineering Pennsylvania State UniversityUniversity ParkPA 16802USA State Key Laboratory for Turbulence and Complex Systems Peking UniversityBeijing 100871China College of Engineering Peking UniversityBeijing 100871China

Machine-learned augmentations to turbulence models can be advantageous for flows within the training dataset but can often cause harm *** lack of generalizability arises because the constants(as well as the functions)in a Reynolds-averaged Navier–Stokes(RANS)model are coupled,and un-constrained re-calibration of these constants(and functions)can disrupt the calibrations of the baseline model,the preservation of which is critical to the model's *** safeguard the behaviors of the baseline model beyond the training dataset,machine learning must be constrained such that basic calibrations like the law of the wall are kept *** letter aims to identify such constraints in two-equation RANS models so that future machine learning work can be performed without violating these *** demonstrate that the identified constraints are not ***,they help preserve the generalizability of the baseline model.

关键词： Machine learning Turbulence modeling Reynolds-averaged Navier-Stokes

Interactive mechanism and friction modelling of transient tribological phenomena in metal forming processes: A review

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Friction 2024年第3期12卷 375-395页

作者： Xiao YANG Heli LIU Lemeng ZHANG Yiran hu Denis j.POLITIS Mohammad M.GHARBI Liliang WANG Department of Mechanical Engineering Imperial College LondonLondon SW72AZUK Department of Mechanical and Manufacturing Engineering University of CyprusNicosia 1678Cyprus Quaker Houghton Deutschland GmbH Dortmund 44319Germany

The accurate representation of tribological boundary conditions at the tool–workpiece interface is crucial for analysis and optimization of formability,material flow,and surface quality of components during metal forming *** has been found that these tribological conditions vary spatially and historically with process parameters and contact *** time-dependent tribological behaviours are also known as transient tribological phenomena,which are widely observed during forming processes and many other manufacturing application ***,constant friction values are usually assigned to represent complex and dynamic interfacial conditions,which would introduce deviations in the relevant *** this paper,transient tribological phenomena and the contemporary understanding of the interaction between friction and wear are reviewed,and it has been found that these phenomena are induced by the transitions of friction mechanisms and highly dependent on complex loading conditions at the *** modelling techniques for transient behaviours for metal forming applications are also *** accurately describe the evolutionary friction values and corresponding wear during forming,the advanced interactive friction modelling has been established for different application scenarios,including lubricated condition,dry sliding condition(metal-on-metal contact),and coated system.

关键词： transient tribological phenomena interactive friction mechanism modelling techniques metal forming

Association of daily sitting time and leisure-time physical activity with body fat among ***

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journal of Sport and Health Science 2024年第2期13卷 195-203页

作者： jingwen Liao Min hu Kellie Imm Clifton j.Holmes jie Zhu Chao Cao Lin Yang Guangdong Provincial Key Laboratory of Physical Activity and Health Promotion Guangzhou Sport UniversityGuangzhou 510500China Scientific Research Center Guangzhou Sport UniversityGuangzhou 510500China Division of Epidemiology&Genetics Department of Population and Public Health SciencesKeck School of Medicine of the University of Southern CaliforniaLos AngelesCA 90033USA Program in Physical Therapy Washington University School of MedicineSt.LouisMO 63110USA Center for human Nutrition Washington University School of MedicineSt.LouisMO 63110USA Department of Plastic and Reconstructive Surgery Shanghai East HospitalTongji UniversityShanghai 200070China Department of Cancer Epidemiology and Prevention Research Alberta Health ServicesCalgary T2S 3C3Canada Department of Oncology and Community Health Sciences University of CalgaryCalgary T2N 1N4Canada

Background:Prolonged sitting and reduced physical activity lead to low energy ***,little is known about the joint impact of daily sitting time and physical activity on body fat *** investigated the independent and joint associations of daily sitting time and physical activity with body fat among ***:This was a cross-sectional analysis of *** representative data from the National Health and Nutrition Examination Survey2011-2018 among adults aged 20 years or *** sitting time and leisure-time physical activity(LTPA)were self-reported using the Global Physical Activity *** fat(total and trunk fat percentage)was determined via dual X-ray ***:Among 10,808 adults,about 54.6%spent 6 h/day or more sitting;more than one-half reported no LTPA(inactive)or less than 150 min/week LTPA(insufficiently active)with only 43.3%reported 150 min/week or more LTPA(active)in the past *** fully adjusting for sociodemographic data,lifestyle behaviors,and chronic conditions,prolonged sitting time and low levels of LTPA were associated with higher total and trunk fat percentages in both *** stratifying by LTPA,the association between daily sitting time and body fat appeared to be stronger in those who were inactive/insuufficiently *** the joint analyses,inactive/insuufficiently active adults who reported sitting more than 8 h/day had the highest total(female:3.99%(95%confidence interval(95%CI):3.09%-4.88%);male:3.79%(95%CI:2.75%-4.82%))and trunk body fat percentages(female:4.21%(95%CI:3.09%-5.32%);male:4.07%(95%CI:2.95%-5.19%))when compared with those who were active and sitting less than 4 h/***:Prolonged daily sitting time was associated with increased body fat among *** higher body fat associated with 6 h/day sitting may not be offset by achieving recommended levels of physical activity.

关键词： Adults Body fat distribution Physical activity Sitting time