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Progress Toward Steady-State Operation on tore Supra

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Plasma Science and Technology 2004年第1期6卷 2101-2108页

作者： J.Jacquinot G.T.Hoang on behalf of the tore Supra Team Euratom-CEA Association CEA/DSM/DRFC CEA Cadarache F-13108 Saint-Paul-Lez-Durance FranceEuratom-CEA Association CEA/DSM/DRFC CEA Cadarache F-13108 Saint-Paul-Lez-Durance FranceEuratom-CEA Association CEA/DSM/DRFC CEA Cadarache F-13108 Saint-Paul-Lez-Durance France

Important technological and physics issues related to steady-state operationrequired for next step are being examined on tore Supra, after a major upgrade of internalcomponents in order to increase the heat extraction capability to 25 MW for 1000 s. Here, we showfirst experimental results, where all the plasma facing components were actively cooled duringpulses exceeding four minutes, with reactor-relevant heat load. New physics was observed innon-inductively driven plasmas, including a stationary peaked radial profile of the plasma densitygenerated by an anomalous inward pinch; and a regime characterized by sinusoidal oscillations ofcentral electron temperature, governed by non-linear coupling between heat transport and plasmacurrent analogous to a predator-prey mechanism.

关键词： steady-state operation tore supra, non-inductively driven plasma

Reconstruction of hollow areas in density profiles from frequency swept reflectometry

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Plasma Science and Technology 2020年第6期22卷 32-40页

作者： Rennan b MORALES Stéphane HEURAUX Roland SAbOT Sébastien HACQUIN Frédéric CLAIRET the tore Supra Team United Kingdom Atomic Energy Authority Culham Centre for Fusion EnergyCulham Science CentreAbingdonOxonOX143DBUnited Kingdom IJL UMR CNRSUniversity of LorraineBP50840NancyF-54011France Institute of Physics University of Sao PauloSao Paulo 05315-970Brazil IRFM CEACadaracheF-13108 Saint-Paul-lez-DuranceFrance EUROfusion Programme Management Unit Culham Science CentreCulham OX143DBUnited Kingdom

The standard density profile reconstruction techniques are based on the WKb approximation of the probing wave’s phase,making them unable to properly reconstruct blind areas in the cut-off frequency *** reconstruction suffers a significant immediate error that is not rapidly *** is demonstrated that even though no reflections occur inside the hollow region causing the blind area,the higher probing frequencies that propagate through it carry information that can be used to estimate its *** usually ignored full-wave effects were investigated with the use of full-wave simulations in 1 D,with special attention paid to the frequency band where they are dominant.A database of perturbation signals was simulated onfive-dimensions of parameters and an application of the database inversion was demonstrated for a magnetic island in a tore Supra *** new adapted reconstruction scheme improved the description of the density profile inside the hollow region and also along 10 cm after it.

关键词： FM-CW reflectometry profile reconstruction reflectometry density profile hollow profile blind area

Subsea Maintenance Service Delivery:Mapping Factors Influencing Scheduled Service Duration

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International Journal of Automation and computing 2010年第2期7卷 167-172页

作者： Efosa Emmanue tore Markeset Faculty of Science and Technology Department of Operations and MaintenanceUniversity of Stavanger Shell Petroleum Development Company

The oil and gas （O＆G） industry on the Norwegian continental shelf （NCS） leads the world in terms of the number of subsea O＆G installations. Ensuring the dependability of these assets is critical. Non-intrusive inspection, maintenance and repair （IMR） services are therefore needed to reduce risks. These services are planned and executed using a mono-hull offshore vessel complete with remotely operated vehicles （ROVs）, a module handling system and an active heave compensated crane. Vessel time is shared between competing jobs, using a prioritized forward-looking schedule. Extension in planned job duration may have an impact on O＆G production, service costs and health, safety, and environmental （HSE） risks. This paper maps factors influencing the job schedule efficiency. The influence factors are identified through reviews of literature as well as interviews with experts in one of the large IMR subsea service providers active on the Norwegian Continental Shelf. The findings show that the most obvious factors are weather disruption and water depth. Other factors include job complexity, job uncertainty, IMR equipment availability, as well as the mix of job complexity.

关键词： Oil and gas assets subsea inspection, maintenance, and repair (IMR) services service delivery influence factors scheduling.

Characterization of carbon black modified by maleic acid

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Frontiers of Materials Science 2013年第3期7卷 302-307页

作者： Vijayshankar ASOKAN Pawel KOSINSKI tore SKODVIN Velaug MYRSETH Department of Physics and Technology The University of Bergen Allegaten 55 Bergen 5007 Norway Carbontech Holding AS Conrad Mohrsvei 9C Bergen 5068 Norway Department of Chemistry The University of Bergen Allegaten 41 Bergen 5007 Norway

We present here a method for modifying the surface of carbon black （Cb） using a simple heat treatment in the presence of a carboxylic acid as well as water or ethylene glycol as a solvent. Cb was mixed with maleic acid and either water or ethylene glycol, and heated at 250℃. Unlike the traditional surface modification processes which use heat treatment of carbon with mineral acids the present modification method using a carboxylic acid proved to be simple and time efficient. Cb from two different vendors was used, and the modified samples were characterized by TGA, bET surface area measurement, XRD, particle size and zeta potential measurements, and FTIR. It was found that several material properties, including thermal stability and surface area, of the modified Cb are significantly altered relative to the parental carbon samples. This method provides a rapid and simple route to tailor new materials with desired properties.

关键词： carbon black (Cb) carboxylic acid ethylene glycol thermal stability surface area

Flow-Induced Acoustics in Corrugated Pipes

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Communications in Computational Physics 2011年第6期10卷 120-139页

作者： Mihaela Popescu Stein tore Johansen Wei Shyy Department of Process Technology Flow TechnologySINTEF Materials and Chemistry7046 TrondheimNorway Department of Aerospace Engineering University of MichiganAnn ArborMI 48109USA

When gas flows through corrugated pipes,pressure waves interacting with vortex shedding can produce distinct tonal noise and structural *** on established observations,a model is proposed which couples an acoustic pipe and selfexcited oscillations with vortex shedding over the corrugation *** the model,the acoustic response of the corrugated pipe is simulated by connecting the lossless medium moving with a constant velocity with a source based on a discrete distribution of van der Pol oscillators arranged along the *** time accurate solutions exhibit dynamic behavior consistent with that experimentally observed,including the lock-in frequency of vortex shedding,standing waves and the onset fluid velocity capable of generating the lock-in.

关键词： Computational fluid dynamics aeroacoustics sound generation riser corrugated pipes wave propagation low Mach number gas flow flow-induced vibrations

Air–Sea Coupling Enhances the East Asian Winter Climate Response to the Atlantic Multidecadal Oscillation

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Advances in Atmospheric Sciences 2015年第12期32卷 1647-1659页

作者： ZHOU Xiaomin LI Shuanglin LUO Feifei GAO Yongqi tore FUREVIK Nansen-Zhu International Research Centre and Climate Change Research Center Institute of Atmospheric PhysicsChinese Academy of Sciences Joint Center for Global Change Studies University of Chinese Academy of Sciences Geophysical Institute and bjerknes Center for Climate Research University of Bergen

A simple air-sea coupled model, the atmospheric general circulation model （AGCM） of the National Centers for Environmental Prediction coupled to a mixed-layer slab ocean model, is employed to investigate the impact of air-sea coupling on the signals of the Atlantic Multidecadal Oscillation （AMO）. A regional coupling strategy is applied, in which coupling is switched off in the extratropical North Atlantic Ocean but switched on in the open oceans elsewhere. The coupled model is forced with warm-phase AMO SST anomalies, and the modeled responses are compared with those from parallel uncoupled AGCM experiments with the same SST forcing. The results suggest that the regionally coupled responses not only resemble the AGCM simulation, but also have a stronger intensity. In comparison, the coupled responses bear greater similarity to the observational composite anomaly. Thus, air-sea coupling enhances the responses of the East Asian winter climate to the AMO. To determine the mechanism responsible for the coupling amplification, an additional set of AGCM experiments, forced with the AMO-induced tropical SST anomalies, is conducted. The SST anomalies are extracted from the simulated AMO-induced SST response in the regionally coupled model. The results suggest that the SST anomalies contribute to the coupling amplification. Thus, tropical air-sea coupling feedback tends to enhance the responses of the East Asian winter climate to the AMO.

关键词： amplification Atlantic Multidecadal Oscillation air-sea coupling feedback East Asian winter climate

Weaker connection between the Atlantic Multidecadal Oscillation and Indian summer rainfall since the mid-1990s

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Atmospheric and Oceanic Science Letters 2018年第1期11卷 37-43页

作者： LUO Fei-Fei LI Shuanglin tore FUREVIK Nansen-Zhu International Research Centre and Climate Change Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Department of Atmospheric Science China University of Geosciences Wuhan China Geophysical Institute and bjerknes Centre for Climate Research University of Bergen Bergen Norway

Previous studies have shown that the Atlantic Multidecadal Oscillation （AMO） can play an important role in modulating the variabilityoflndian summer monsoon rainfall （ISMR） over a 50-60-yr timescale. A significant positive correlation between the AMO and ISMR is found both in observations and models. However, instrumental records show that the relationship becomes non-significant or even of opposite sign after the mid-1990s, suggesting a weakening of the AMO-ISMR connection. The mechanism for the breakdown of the AMO-ISMR connection is investigated in the present work, and the results suggest that a substantial warming in the Indian-tropical western Pacific Ocean plays a role. The warming weakens the meridional gradient of tropospheric temperature between Eurasia and the indian Ocean, and reduces the meridional sea level pressure gradient between the Indian Subcontinent and Indian Ocean, weakening the Indian summer monsoon. Thus, warming in the Indian-tropical western Pacific Ocean seems responsible for the weakened connection between the AMO and ISM.

关键词： Atlantic MultidecadalOscillation Indian summerrainfall connection multidecadal variation

Teleconnection between Sea Ice in the barents Sea in June and the Silk Road,Pacific–Japan and East Asian Rainfall Patterns in August

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Advances in Atmospheric Sciences 2018年第1期35卷 52-64页

作者： Shengping HE Yongqi GAO tore FUREVIK Huijun WANG Fei LI Geophysical Institute University of Bergen and Bjerknes Centre for Climate ResearchBergen 5007Norway Nansen-Zhu International Research Centre Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Nansen Environmental and Remote Sensing Center Bergen 5006Norway Climate Change Research Center Chinese Academy of SciencesBeijing 100029China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Key Laboratory of Meteorological Disaster Ministry of EducationNanjing University of Information Science and TechnologyNanjing 210044China NILU--Norwegian Institute for Air Research Kjeller 2007Norway

In contrast to previous studies that have tended to focus on the influence of the total Arctic sea-ice cover on the East Asian summer tripole rainfall pattern, the present study identifies the barents Sea as the key region where the June sea-ice variability exerts the most significant impacts on the East Asian August tripole rainfall pattern, and explores the teleconnection mechanisms involved. The results reveal that a reduction in June sea ice excites anomalous upward air motion due to strong near-surface thermal forcing, which further triggers a meridional overturning wave-like pattern extending to *** downward motion therefore forms over the Caspian Sea, which in turn induces zonally oriented overturning circulation along the subtropical jet stream, exhibiting the east–west Rossby wave train known as the Silk Road pattern. It is suggested that the bonin high, a subtropical anticyclone predominant near South Korea, shows a significant anomaly due to the eastward extension of the Silk Road pattern to East Asia. As a possible descending branch of the Hadley cell, the bonin high anomaly ultimately triggers a meridional overturning, establishing the Pacific–Japan pattern. This in turn induces an anomalous anticyclone and cyclone pair over East Asia, and a tripole vertical convection anomaly meridionally oriented over East Asia. Consequently, a tripole rainfall anomaly pattern is observed over East Asia. Results from numerical experiments using version 5 of the Community Atmosphere Model support the interpretation of this chain of events.

关键词： sea-ice reduction tripole rainfall Silk Road pattern Pacific–Japan pattern teleconnection

Modelling of temperature and strain rate dependent behaviour of pearlitic steel in block braked railway wheels

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Railway Engineering Science 2021年第4期29卷 362-378页

作者： Ali Esmaeili Johan Ahlstrom Magnus Ekh Dimitrios Nikas tore Vernersson CHARMEC/Department of Industrial and Materials Science Chalmers University of TechnologyGothenburgSweden Now at Department of Engineering and Physics Karlstad UniversityKarlstadSweden CHARMEC/Department of Mechanics and Maritime Sciences Chalmers University of TechnologyGothenburgSweden

block braked railway wheels are subjected to thermal and rolling contact *** thermal loading results in high temperatures and thermal stresses which cause slow time dependent processes such as creep,relaxation and static recovery of the wheel *** the same time,the rolling contact loading implies a very fast mechanical load *** paper is focused on material modeling of pearlitic steel for a wide range of loading rates at elevated *** starting point is a viscoplasticity model including nonlinear isotropic and kinematic *** Delobelle overstress function is employed to capture strain rate dependent response of the *** model also includes static recovery of the hardening to capture slower viscous(diffusion dominated)behaviour of the *** for the pearlitic wheel steel ER7 in terms of cyclic strain-controlled uniaxial tests with hold-time,uniaxial ratchetting tests including rapid cycles and biaxial cyclic tests with tension/compression and torsion are used to calibrate the material *** experiments were performed under isothermal conditions at different *** the ratchetting tests,higher loading rates are obtained and these have been used to calibrate the high strain rate response of the viscoplasticity *** paper is concluded with a numerical example of a block braked wheel where the importance of accounting for the viscoplasticity in modelling is highlighted.

关键词： block braking High temperatures Pearlitic steel Railway wheels Viscoplasticity