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Application of supervised machine learning to predict the enhanced gas recovery by CO2 injection in shale gas reservoirs

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Petroleum 2024年第1期10卷 124-134页

作者： Moataz Mansi Mohamed Almobarak Jamiu Ekundayo christopher Lagat Quan Xie Discipline of Petroleum Engineering WA School of Mines: Minerals Energy and Chemical Engineering Curtin University

The technique of Enhanced Gas Recovery by CO2injection（CO2-EGR） into shale reservoirs has brought increasing attention in the recent decade. CO2-EGR is a complex geophysical process that is controlled by several parameters of shale properties and engineering design. Nevertheless, more challenges arise when simulating and predicting CO2/CH4displacement within the complex pore systems of shales. Therefore,the petroleum industry is in need of developing a cost-effective tool/approach to evaluate the potential of applying CO2injection to shale reservoirs. in recent years, machine learning applications have gained enormous interest due to their high-speed performance in handling complex data and efficiently solving practical problems. Thus, this work proposes a solution by developing a supervised machine learning（ML） based model to preliminary evaluate CO2-EGR efficiency. Data used for this work was drawn across a wide range of simulation sensitivity studies and experimental investigations. in this work, linear regression and artificial neural networks（ANNs） implementations were considered for predicting the incremental enhanced CH4. Based on the model performance in training and validation sets, our accuracy comparison showed that（ANNs） algorithms gave 15% higher accuracy in predicting the enhanced CH4compared to the linear regression model. To ensure the model is more generalizable, the size of hidden layers of ANNs was adjusted to improve the generalization ability of ANNs model. Among ANNs models presented, ANNs of 100 hidden layer size gave the best predictive performance with the coefficient of determination（R2） of 0.78 compared to the linear regression model with R2of 0.68. Our developed MLbased model presents a powerful, reliable and cost-effective tool which can accurately predict the incremental enhanced CH4by CO2injection in shale gas reservoirs.

关键词： Artificial intelligence Supervised Machine Learning Shale Gas Enhanced Shale Gas Recovery CO 2 injection CO 2 sequestration

Comparison of ERA5 turbulent fluxes at the air-sea interface with measurements from a wave-following platform

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Atmospheric and Oceanic Science Letters 2024年第3期17卷 32-36页

作者： Said Benjeddou Denis Bourras christopher Luneau Aix Marseille Universite National Center for Scientific ResearchMediterranean Institute of OceanographyMarseilleFrance Observatory of the Sciences of the Universe Pytheas institute National Center for Scientific ResearchMarseilleFrance

Turbulent fluxes at the air-sea interface were estimated with data collected in 2011-2020 with a low-profile platform named OCARiNA during eight experiments in five regions:2011,2015,and 2016 in the iroise Sea;2012 in the tropical Atlantic;2014 in the Chilie-Peru upwelling;2017 and 2018 in the Mediterranean Sea,and 2018 and 2020 in *** observations were carried out with moderate winds(2-10 m s^(-1))and average wave heights of 1.5 *** this study,the authors used the fluxes calculated by the bulk method using OCARiNA-sampled data as the *** data can validate the fluxes estimated from ERAS reanalysis *** OCARiNA and ERA5 data were taken *** do this,the authors established an algorithm to extract the OCARiNA data as closely as possible to the reanalysis data in time and *** measurements of the OCARiNA platform can conclude on the relevance of the widely used reanalysis data.

关键词： Ocarina ECMWF ERA5 Turbulent fluxes Louis formulation

A Review of State-of-the-art Flexible Power Point Tracking Algorithms in Photovoltaic Systems for Grid Support:Classification and Application

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 1-21页

作者： Mina Haghighat Mehdi Niroomand Hossein Dehghani Tafti christopher D.Townsend Tyrone Fernando the Department of Electrical Engineering University of IsfahanIsfahanIran the Department of Electrical Electronic and Computer EngineeringUniversity of Western AustraliaCrawley WA 6009Australia

To maximize conversion efficiency,photovoltaic(PV)systems generally operate in the maximum power point tracking(MPPT)***,due to the increasing penetra tion level of PV systems,there is a need for more developed control functions in terms of frequency support services and voltage control to maintain the reliability and stability of the power ***,flexible active power control is a manda tory task for grid-connected PV systems to meet part of the grid ***,a significant number of flexible pow er point tracking(FPPT)algorithms have been introduced in the existing *** purpose of such algorithms is to real ize a cost-effective method to provide grid support functional ities while minimizing the reliance on energy storage *** paper provides a comprehensive overview of grid support functionalities that can be obtained with the FPPT control of PV systems such as frequency support and volt-var *** of these grid support functionalities necessitates PV sys tems to operate under one of the three control strategies,which can be provided with FPPT *** three control strate gies are classified as:①constant power generation control(CP GC),②power reserve control(PRC),and③power ramp rate control(PRRC).A detailed discussion on available FPPT algo rithms for each control strategy is also *** paper can serve as a comprehensive review of the state-of-the-art FPPT algorithms that can equip PV systems with various grid support functionalities.

关键词： Maximum power point tracking(MPPT) flexi ble power point tracking(FPPT) power reserve control(PRC) power ramp rate control(PRRC) low voltage ride-through(LVRT) constant power generation(CPG)

Biophotoelectrochemistry:An emerging frontier for channeling photoelectric effect into darkness zone of soils and sediments

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Pedosphere 2024年第1期34卷 5-8页

作者： Jie YE Shungui ZHOU Kenneth H.NEALSON christopher RENSiNG Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation College of Resources and EnvironmentFujian Agriculture and Forestry UniversityFuzhou 350002China Department of Earth Science University of Southern CaliforniaLos Angeles CA 90007USA

Solar energy captured by photosynthetic plants in the photic zone is recognized as the main driver for the formation of organic matter utilized by soil communities. However, the contribution of organic transformation to the linkage of solar energy and microbial metabolism of soils is reduced when the vadose zone is saturated. in contrast to the conventional biophotoelectrochemistry via photosynthesis with phytoplankton during the periodic saturation of soils, recent studies suggest that non-phototrophic microorganisms in soils and sediments are able to conduct light-dependent metabolism to sustain their functionality with photosensitizers under illumination. These interactions and processes utilize long-distance electron transfer networks to interconnect diverse electron transfer chains that channel photoexcited electrons into the opaque zone for soil communities. Such an emerging process not only allows for a better understanding of biogeochemical processes such as soil carbon sequestration and mitigation, but also shows great potential for environmental treatment such as the bioremediation of contaminated soils. Therefore, we suggest that biophotoelectrochemistry via photoelectric effect can have significant, heretofore unappreciated, theoretical and practical values.

关键词： soils soil metabolism

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Coverage and determinants of infant postnatal care in Nigeria:A population-based cross-sectional study

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Pediatric investigation 2024年第1期8卷 27-36页

作者： Bolaji Emmanuel Egbewale Olusola Oyedeji Jesse Bump christopher Robert Sudfeld Department of Global Health and Population Takemi Program in International HealthHarvard T.H.Chan School of Public HealthBostonMassachusettsUSA Department of Community Medicine College of Health SciencesLadoke Akintola University of TechnologyOgbomosoNigeria Department of Pediatrics and Child Health College of Health SciencesLadoke Akintola University of TechnologyOgbomosoNigeria

importance:in 2019,Nigeria had the largest number of under-5 child deaths globally and many of these deaths occurred within the first week of *** World Health Organization recommends infant postnatal care(PNC)attendance to support newborn survival;however,utilization of PNC is known to be low in many ***:This study examined coverage and individual-level determinants of infant PNC attendance in ***:Nigeria Demographic Health Survey(NDHS)2018 data were used to evaluate infant PNC coverage and *** PNC was defined as receipt of care within 2 days of *** delivered up to 2 years before the 2018 NDHS were *** examined predictors of infant PNC with modified Poisson regression models to estimate relative risks(RRs).Results:The national coverage of infant PNC was 37.3%(95%confidence interval[Ci]:35.8%–38.7%).Significant heterogeneity in PNC attendance existed at state and regional *** delivery was strongly associated with the uptake of PNC(RR:6.07;95%Ci:5.60–6.58).Greater maternal education,maternal employment,urban residence,female head of household,and greater wealth were also associated with an increased likelihood of PNC ***:The uptake of infant PNC is low and interventions are urgently needed to promote equity in access and increase demand for PNC in Nigeria.

关键词： infant postnatal care Epidemiology Coverage Determinants Nigeria

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ACC for generalized log canonical thresholds for complex analytic spaces

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Science China Mathematics 2024年

作者： christopher D.Hacon Lingyao Xie University of Utah Department of Mathematics

We show that generalized log canonical thresholds for complex analytic spaces satisfy the ACC(ascending chain condition) and we characterize the accumulation points.

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Exploring impacts of COViD-19 on spatial and temporal patterns of visitors to Canadian Rocky Mountain National Parks from social media big data

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Journal of Forestry Research 2024年第4期35卷 13-33页

作者： Dehui Christina Geng Amy Li Jieyu Zhang Howie W.Harshaw christopher Gaston Wanli Wu Guangyu Wang National Park Research Centre Faculty of ForestryUniversity of British ColumbiaVancouver V6T 1Z4Canada Faculty of Applied Science University of British ColumbiaVancouver V6T 1Z3Canada Paul G.Allen School of Computer Science&Engineering University of WashingtonSeattleWA 98195USA Faculty of Kinesiology Sportand RecreationUniversity of AlbertaEdmonton T6G 2J9Canada Department of Wood Science Faculty of ForestryUniversity of British ColumbiaVancouver V6T 1Z4Canada

COViD-19 posed challenges for global tourism *** in visitor temporal and spatial patterns and their associated determinants pre-and peri-pandemic in Canadian Rocky Mountain National Parks are *** was collected through social media programming and analyzed using spatiotemporal analysis and a geographically weighted regression(GWR)*** highlight that COViD-19 significantly changed park visitation *** tended to explore more remote areas *** GWR model also indicated distance to nearby trails was a significant influence on visitor *** results indicate that the pandemic influenced tourism temporal and spatial *** research presents a novel approach using combined social media big data which can be extended to the field of tourism management,and has important implications to manage visitor patterns and to allocate resources efficiently to satisfy multiple objectives of park management.

关键词： Tourism management Social media big data National parks COViD-19 Geographical weighted regression

Phosphorus limitation on CO_(2)fertilization effect in tropical forests informed by a coupled biogeochemical model

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Forest Ecosystems 2024年第4期11卷 502-515页

作者： Zhuonan Wang Hanqin Tian Shufen Pan Hao Shi Jia Yang Naishen Liang Latif Kalin christopher Anderson Natural Resources Ecology Laboratory Colorado State UniversityFort CollinsCO80523USA Center for Earth System Science and Global Sustainability Schiller Institute for Integrated Science and SocietyBoston CollegeChestnut HillMAUSA Department of Earth and Environmental Sciences Boston CollegeChestnut HillMAUSA Department of Engineering Boston CollegeChestnut HillMAUSA Research Center for Eco-Environmental Sciences State Key Laboratory of Urban and Regional EcologyChinese Academy of SciencesBeijingChina Department of Natural Resource Ecology and Management Oklahoma State UniversityStillwaterOKUSA Center for Global Environmental Research(CGER) National Institute for Environmental Studies(NIES)TsukubaIbaraki305-8506Japan College of Forestry Wildlife and EnvironmentAuburn UniversityAuburnALUSA

Tropical forests store more than half of the world's terrestrial carbon(C)pool and account for one-third of global net primary productivity(NPP).Many terrestrial biosphere models(TBMs)estimate increased productivity in tropical forests throughout the 21st century due to CO_(2)***,phosphorus(P)liaitations on vegetation photosynthesis and productivity could significantly reduce the CO_(2)fertilization ***,we used a carbon-nitrogen-phosphorus coupled model(Dynamic Land Ecosystem Model;DLEM-CNP)with heterogeneous maximum carboxylation rates to examine how P limitation has affected C fluxes in tropical forests *** model results showed that the inclusion of the P processes enhanced model performance in simulating ecosystem *** further compared the simulations from DLEM-CNP,DLEM-CN,and DLEMC and the results showed that the inclusion of P processes reduced the CO_(2)fertilization effect on gross primary production(GPP)by 25%and 45%,and net ecosystem production(NEP)by 28%and 41%,respectively,relative to CN-only and C-on ly *** the 1860s to the 2010s,the DLEM-CNP estimated that in tropical forests GPP increased by 17%,plant respiration(Ra)increased by 18%,ecosystem respiration(Rh)increased by 13%,NEP increased by 121%per unit area,***,factorial experiments with DLEM-CNP showed that the enhanced NPP benefiting from the CO2 fertilization effect had been offset by 135%due to deforestation from the 1860s to the *** study highlights the importance of P limitation on the C cycle and the weakened CO_(2)fertilization effect resulting from P limitation in tropical forests.

关键词： Tropical forests Carbon-nitrogen-phosphorus model Phosphorus limitation CO_2 fertilization effect Terrestfial ecosy stem model

A framework for dynamic modelling of railway track switches considering the switch blades,actuators and control systems

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Railway Engineering Science 2024年第2期32卷 162-176页

作者： Saikat Dutta Tim Harrison christopher Ward Roger Dixon Phil Winship institute of Thermofluids School of Mechanical EngineeringUniversity of LeedsLeedsWest YorkshireUK Wolfson School of Mechanical Electrical and Manufacturing EngineeringLoughborough UniversityLoughboroughLeicestershireUK Birmingham Centre for Railway Research and Education School of EngineeringUniversity of BirminghamBirminghamWest MidlandsUK Network Rail Milton KeynesBuckinghamshireUK

The main contribution of this paper is the development and demonstration of a novel methodology that can be followed to develop a simulation twin of a railway track switch system to test the functionality in a digital *** is important because,globally,railway track switches are used to allow trains to change routes;they are a key part of all railway ***,because track switches are single points of failure and safety-critical,their inability to operate correctly can cause significant delays and concomitant *** order to better understand the dynamic behaviour of switches during operation,this paper has developed a full simulation twin of a complete track switch *** approach fuses finite element for the rail bending and motion,with physics-based models of the electromechanical actuator system and the control ***,it provides researchers and engineers the opportunity to explore and understand the design space around the dynamic operation of new switches and switch machines before they are *** is useful for looking at the modification or monitoring of existing switches,and it becomes even more important when new switch concepts are being considered and *** simulation is capable of running in real time or faster meaning designs can be iterated and checked *** paper describes the modelling approach,demonstrates the methodology by developing the system model for a novel“REPOiNT”switch system,and evaluates the system level performance against the dynamic performance requirements for the *** the context of that case study,it is found that the proposed new actuation system as designed can meet(and exceed)the system performance requirements,and that the fault tolerance built into the actuation ensures continued operation after a single actuator failure.

关键词： Railway track switch Mathematical modelling Redundant actuation Finite element analysis

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