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Experimental Modelling of the Impact of a DC Magnetic Field on the Melt Flow in a Continuous Casting Mould

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Journal of Iron and Steel Research International 2012年第S2期19卷 862-865页

作者： TIMMEL Klaus wondrak thomas RDER Michael STEFANI Frank ECKERT Sven GERBETH Gunther Helmholtz-Zentrum Dresden-Rossendorf

This paper describes experimental investigations of flow structures and related transport processes in the continuous casting mould under the influence of an external DC magnetic field at laboratory *** results will be presented here which have been obtained using a physical model(mini-LIMMCAST)operating with the low melting point alloy *** to the concept of the electromagnetic brake the impact of a DC magnetic field on the outlet flow from the Submerged Entry Nozzle(SEN)has been studied up to Hartmann numbers of about *** Ultrasound-Doppler-Velocimetry(UDV)was applied for measurements of the flow pattern in the *** conductivity anemometers were used to measure the turbulent quantities of the *** effect of the magnetic field on the flow structure turned out to be manifold and rather *** magnetic field causes a deflection of the jet,at which the respective exit angle from the nozzle ports becomes more ***,both the penetration depth of the discharging flow into the lower part of the mould and the impinging velocity of the jet onto the side wall are reduced.A significant return flow occurs in the adjacent regions of the *** vortices are formed with axes being aligned with the magnetic field *** vortical structures are typical for quasi-two-dimensional magneto-hydrodynamic(MHD)*** flow measurements do not manifest a general braking effect which would be expected as an overall damping of the flow velocity and the related fluctuations all-over the mould *** of the wall conductivity showed a striking impact on the resulting flow structures.

关键词： continuous casting liquid metal model electromagnetic brake ultrasonic flow measurement potential probes

Liquid Metal Modelling of Continuous Steel Casting

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Liquid Metal Modelling of Continuous Steel Casting

Insights into carbon dioxide sequestration into coal seams through coupled gas flow-adsorption-deformation modelling

第十届中国钢铁年会暨第六届宝钢学术年会

作者： Gerbeth Gunter wondrak thomas Stefani Frank Shevchenko Natalia Eckert Sven Timmel Klaus Helmholtz-Zentrum Dresden-Rossendorf Institute of Fluid Dynamics MHD Department

Model experiments with low melting point liquid metals are an important tool to investigate the flow structure and related transport processes in melt flows relevant for metallurgical applications. We present recent results from the three LIMMCAST facilities working either with room-temperature alloy Ga In Sn or with the alloy Sn Bi at temperatures of 20050°C. The main value of cold metal laboratory experiments consists in the capabilities to obtain quantitative flow measurements with a reasonable spatial and temporal resolution, which is essential for code validation. Experimental results are presented covering the following phenomena: contactless electromagnetic tomography of the flow in the mold, flow monitoring by ultrasonic sensors, mold flow under the influence of an electromagnetic brake, injection of argon bubbles through the stopper rod, X-ray visualization of gas bubble two-phase flow in the nozzle and in the mold.

关键词： continuous casting physical modeling flow measurements magnetic field flow control electromagnetic brake

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 26-40页

作者： Hywel thomas Min Chen Geoenvironmental Research Centre Cardiff School of EngineeringCardiff UniversityQueen’s BuildingsThe ParadeNewport RoadCardiffCF243AAUK Key Laboratory of Marine Geology Tongji UniversityShanghai200092China

Injecting carbon dioxide(CO_(2))into coal seams may unlock substantial carbon sequestration *** the coal acts like a carbon filter,it can preferentially absorb significant amounts of CO_(2).To explore this further,desorption of the adsorbed gas due to pressure drop is investigated in this paper,to achieve an improved understanding of the long-term fate of injected CO_(2) during post-injection *** paper presents a dual porosity model coupling gas flow,adsorption and geomechanics for studying coupled processes and effectiveness of CO_(2) sequestration in coals.A new adsorption?desorption model derived based on thermodynamics is incorporated,particularly,the desorption hysteresis is *** reliability of the proposed adsorption-desorption isotherm is examined via validation *** is indicated that occurrence of desorption hysteresis is attributed to the adsorption-induced pore *** injection ceases,the injected gas continues to propagate further from the injection well,while the pressure in the vicinity of the injection well experiences a significant *** the adsorbed gas near the well also decreases,this decrease is less compared to that in pressure because of desorption *** unceasing spread of CO_(2) and drops of pressure and adsorbed gas depend on the degree of desorption hysteresis and heterogeneity of coals,which should be considered when designing CO_(2) sequestration into coal seams.

关键词： CO_(2)geological storage Coal seam Adsorption Desorption hysteresis

CLASSIFICATIONS OF DUPIN HYPERSURFACES IN LIE SPHERE GEOMETRY

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Acta Mathematica Scientia 2024年第1期44卷 1-36页

作者： thomas E.CECIL Department of Mathematics and Computer Science College of the Holy CrossWorcesterMA01610USA

This is a survey of local and global classification results concerning Dupin hypersurfaces in S^(n)(or R^(n))that have been obtained in the context of Lie sphere *** emphasis is on results that relate Dupin hypersurfaces to isoparametric hypersurfaces in *** with these classification results,many important concepts from Lie sphere geometry,such as curvature spheres,Lie curvatures,and Legendre lifts of submanifolds of S^(n)(or R^(n)),are described in *** paper also contains several important constructions of Dupin hypersurfaces with certain special properties.

关键词： Dupin hypersurfaces isoparametric hypersurfaces Lie sphere geometry Lie sphere transformations Lie curvatures

Proximity-dependent protein (de)stabilization: screening the human ORFeome for protein degraders and stabilizers

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Signal Transduction and Targeted Therapy 2024年第8期9卷 3161-3162页

作者： thomas Hermanns Kay Hofmann Institute for Genetics University of CologneCologneGermany

In a recent study published in Nature,Poirson et *** an unbiased screen for proteins that can either bring about-or prevent-the destruction of proteinaceous model substrates in a proximity-dependent *** of such protein degraders and stabilizers will be instrumental in the development of new drug classes that specifically regulate the abundance of their target proteins.

关键词： al. stabilization stabilizers

How to enhance agricultural plastic waste management in China?Insights from public participation

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Journal of Integrative Agriculture 2024年第6期23卷 2127-2143页

作者： Aibo Hao thomas Dogot Changbin Yin State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China Institute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural SciencesBeijing 100081China Economics and Rural Development Laboratory TERRA Teaching and Research CentreGembloux Agro-Bio TechUniversity of LiègeGembloux B-5030Belgium Research Center for Agricultural Green Development in China Beijing 100081China

Agricultural plastics play a pivotal role in agricultural ***,due to expensive costs,agricultural plastic waste management(APWM)encounters a vast funding *** one of the crucial stakeholders,the public deserves to make appropriate efforts for ***,identifying whether the public is willing to pay for APWM and clarifying the decisions’driving pathways to explore initiatives for promoting their payment intentions are essential to address the dilemma confronting *** this end,by applying the extended theory of planned behavior(TPB),the study conducted an empirical analysis based on 1,288 residents from four provinces(autonomous regions)of northern *** illustrate that:1)respondents hold generally positive and relatively strong payment willingness towards APWM;2)respondents’attitude(AT),subjective norm(SN),and perceived behavioral control(PBC)are positively correlated with their payment intentions(INT);3)environmental cognition(EC)and environmental emotion(EE)positively moderate the relationships between AT and INT,and between SN and INT,posing significant indirect impacts on *** study’s implications extend to informing government policies,suggesting that multi-entity cooperation,specifically public payment for APWM,can enhance agricultural non-point waste management.

关键词： agricultural plastic waste extended theory of planned behavior public payment environmental cognition environmental emotion

Theory and classification of mass extinction causation

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National Science Review 2024年第1期11卷 16-36页

作者： thomas J.Algeo Jun Shen State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences—Wuhan State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences—Wuhan Department of Geosciences University of Cincinnati

Theory regarding the causation of mass extinctions is in need of systematization, which is the focus of this contribution. Every mass extinction has both an ultimate cause, i.e. the trigger that leads to various climato-environmental changes, and one or more proximate cause(s), i.e. the specific climato-environmental changes that result in elevated biotic mortality. With regard to ultimate causes, strong cases can be made that bolide(i.e. meteor) impacts, large igneous province(LIP) eruptions and bioevolutionary events have each triggered one or more of the Phanerozoic Big Five mass extinctions, and that tectono-oceanic changes have triggered some second-order extinction events. Apart from bolide impacts, other astronomical triggers(*** flares, gamma bursts and supernova explosions) remain entirely in the realm of speculation. With regard to proximate mechanisms, most extinctions are related to either carbon-release or carbon-burial processes, the former being associated with climatic warming, ocean acidification, reduced marine productivity and lower carbonate δ13C values, and the latter with climatic cooling, increased marine productivity and higher carbonate δ13C values. Environmental parameters such as marine redox conditions and terrestrial weathering intensity do not show consistent relationships with carbon-cycle *** this context, mass extinction causation can be usefully classified using a matrix of ultimate and proximate factors. Among the Big Five mass extinctions, the end-Cretaceous biocrisis is an example of a bolide-triggered carbon-release event, the end-Permian and end-Triassic biocrises are examples of LIP-triggered carbon-release events, and the Late Ordovician and Late Devonian biocrises are examples of bioevolution-triggered carbon-burial events. Whereas the bolide-impact and LIP-eruption mechanisms appear to invariably cause carbon release, bioevolutionary triggers can result in variable carbon-cycle changes, e.g. carbon burial durin

关键词： biocrisis ultimate cause proximate cause bolide large igneous province bioevolutionary event

Effects of the urban landscape on heatwave-mortality associations in Hong Kong: comparison of different heatwave definitions

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Frontiers of Environmental Science & Engineering 2024年第1期18卷 145-156页

作者： Jinglu Song Yi Lu thomas Fischer Kejia Hu Department of Urban Planning and Design Xi’an Jiaotong-Liverpool UniversitySuzhou 215123China Department of Architecture and Civil Engineering City University of Hong KongKowloon TongHong Kong 999077China Environmental Assessment and Management Research Centre School of Environmental SciencesUniversity of LiverpoolLiverpool L35TRUK Research Unit for Environmental Sciences and Management Faculty of Natural and Agricultural SciencesNorth West UniversityPotchefstroom 31750South Africa Institute of Big Data in Health Science School of Public HealthZhejiang UniversityZijingang CampusHangzhou 310058China

Despite increased attention given to potential modifiers of temperature-mortality associations, evidence for variations between different urban landscape characteristics remains limited. It is in this context that in this paper effect modifications of multiple urban landscape characteristics are explored under different heatwave definitions for different age groups and gender in Hong Kong, China. Daily meteorological data and heatwave-related mortality counts from 2008 to 2017 were collected from the Hong Kong Census and Statistics Department, China. A case-only design was adopted, combined with logistic regression models to examine the modification effects of five urban landscape characteristics under six heatwave definitions. Stratified analyses were conducted to investigate age- and gender-specific effect modifications. It is found that individuals living in greener areas experienced lower levels of mortality during or immediately after heatwaves. In contrast, a higher building density and nighttime land surface temperature (LST) were associated with a higher heatwave-related mortality risk. Pronounced effect modifications of these urban landscape characteristics were observed under hotter and longer heatwaves, and in older adults (age ≥ 65 years) and males. The findings provide a scientific basis for policymakers and practitioners when considering measures for coping with hotter, longer, and more frequent heatwaves in the context of global climate change.

关键词： Urban landscape Heatwave Mortality Effect modification Intra-urban differences Health risk reduction

Utilizing blockchains in opportunistic networks for integrity and confidentiality

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BLOCKCHAIN-RESEARCH AND APPLICATIONS 2024年第1期5卷 31-38页

作者： Rashidibajgan, Samaneh Hupperich, thomas Univ Munster Dept Informat Syst Cyber Secur D-80539 Munster Germany

Opportunistic networks (OppNets) are usually a set of smart, wearable, and portable devices or entities with mobility that connect wirelessly without requiring infrastructure. Such a network is of great importance in data transmission, particularly in incidents and disasters, whether man-made or natural. However, message integrity and confidentiality are of concern when dealing with vital and physiological data transmission under strict privacy regulations. In this work, we propose a structure to classify messages based on their priority in different queues. Furthermore, due to the decentralized architecture of OppNets, we propose a blockchain-based structure for providing security for high -priority messages. It contains three sequences of functional blocks with a light and simplified implementation that make it suitable for battery -powered wearable devices that are limited in energy consumption and computational units. The simulation results show that by increasing the number of nodes in the network, the average of the changes in block sizes is neglectable, which addresses the computation bottleneck. Furthermore, we analyze the performance of the proposed structure in terms of message delivery and network overhead compared with the Epidemic and Prophet routing algorithms. These results indicate advancing the overall performance of the proposed algorithm.

关键词： Opportunistic networks Blockchain Message integrity Message confidentiality LEARNING APPROACH IOT INTERNET