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Comparing two IBM implementations for the simulation of uniform packed beds

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Particuology 2024年第3期86卷 1-12页

作者： Christian Gorges Maximilian Brommer christin.Velten Siegmar Wirtz Enric Illana Mahiques Viktor Scherer Katharina Zahringer Berend van Wachem Mechanical Process Engineering Otto-von-Guericke-Universitat MagdeburgUniversitatsplatz 239106MagdeburgGermany Department of Energy Plant Technology Ruhr-Universitat BochumUniversitatsstraBe 15044780BochumGermany Laboratory of Fluid Dynamics and Technical Flows Otto-von-Guericke-Universitat MagdeburgUniversitatsplatz 239106MagdeburgGermany

Nowadays,the design of fixed packed bed reactors still relies on empirical correlations,which,especially for small tube to particle diameter ratios,are mostly too inaccurate because of the presence of wall ***,the simulation of fixed packed bed reactors plays an important role to predict and control the flow and process parameters in such,nowadays and in the *** of its straightforward applicability to non-uniform packings with particles of arbitrary shapes,the immersed boundary method(IBM)has advantages over other numerical methods and is used more and more *** paper compares two approaches of IBMs for the simulation of fixed bed reactors with spherical shaped *** classic,smooth approach is compared to the straightforward to implement blocked-off method for velocity fields above the fixed bed for particle Reynolds numbers of 300 and *** from experimental inline PIV-measurements of the reactor to be simulated serve as a basis for *** good agreement with the experiment is found for both simulation methodologies with higher resolutions,considering the more stable flow at a particle Reynolds number of *** in the different IBM approaches occurred for the more unsteady flow at a particle Reynolds number of *** to the blocked-off method,the smooth IBM reflects the formation of additional jets and recirculation zones better right above the bed,though increasing the fluid mesh resolution improves the accuracy of the blocked-off ***,a more diffusive behaviour is found for the blocked-off simulations due to the stairstep representation,which is avoided by using interpolation stencils as in the smooth *** higher mesh refinement in the blocked-off IBM this effect can be reduced,but this also increases the computational effort.

关键词： Immersed boundary method Packed bed reactor Uniform particle packing

从模型到应用:基于生态系统服务权衡的乡村生态修复规划工具研究

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园林 2024年第3期41卷 4-12页

作者：董楠楠王怡琪 Harald Zepp Lars Gruenhagen Malte Bührs christin.Busch 魏维轩同济大学建筑与城市规划学院上海200092 波鸿鲁尔大学地理学系波鸿44801 ILS-国家和城市发展研究所有限公司多特蒙德D-44135

在全球范围内的气候变化背景下,具有多种功能和服务价值的乡村生态空间成为当下国际生态规划研究与合作的关注热点之一。为实现乡村生态空间的精准管理与规划,中德双方围绕联合课题“生态系统服务概念在德国鲁尔与中国大都市区韧性发展... 详细信息

在全球范围内的气候变化背景下,具有多种功能和服务价值的乡村生态空间成为当下国际生态规划研究与合作的关注热点之一。为实现乡村生态空间的精准管理与规划,中德双方围绕联合课题“生态系统服务概念在德国鲁尔与中国大都市区韧性发展模式下的绿色基础设施规划应用”进行了深入探索。在土地利用与土地覆盖类型的基础上,进一步识别了生物群落类型,并基于调节、供给、文化三大生态系统服务类型,选取了评估生态系统服务供需权衡的指标和对应权重,构建了乡村生态空间规划场景下的生态系统服务价值评测模型。以上海市水库村为例,运用该课题的评测模型,初步评估了典型乡村生态规划场景下的生态系统服务价值。最后,从应用尺度、研究范围以及操作流程三个方面总结了该评测模型的优化方向。

关键词：乡村生态修复生态系统服务供需权衡决策辅助工具

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Sumixam maximus *** ***.,a New Pennsylvanian Species of Archaeorthoptera(Neoptera;Indiana,USA)

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Acta Geologica Sinica(English Edition) 2011年第3期85卷 515-520页

作者： Olivier BTHOUX christin.GROSSMANN Freiberg University of Mining and Technology Institute of GeologyDepartment of PalaeontologyD09596 FreibergGermany Senckenberg Natural History Collections of Dresden Museum of ZoologyD-01109 DresdenGermany Senckenberg Natural History Collections of Dresden Museum of Zoology D-01109 DresdenGermany

A new Mazon-Creek-type fossil specimen is described as Sumixam maximus *** ***., assigned to the taxon Archaeorthoptera Bethoux and Nel,2002(composed of Orthoptera and some fossil relatives):it exhibits one of the diagnostic character states of this taxon,which is the fusion of CuA(emerging from M+CuA)with CuP,or a branch of it.A more precise taxonomic assignment is out of *** new taxon exhibits a fusion of the anterior branch of MA with RP,and a point of divergence of MA and MP located near the point of divergence of CuA(from M + CuA),but lack a branching of *** unique combination of character states is probably derived with respect to a number of contemporaneous *** maximus *** *** most likely the closest known relative of the panorthopterans,which include all the recent Archaeorthoptera.

关键词： Insecta Upper Carboniferous Mazon Creek

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Thermal desorption of mercury from lignite in a high-temperature furnace and in power plant mills

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International Journal of Coal Science & Technology 2022年第5期9卷 150-159页

作者： Anne-christin.Kropp Kathrin Gebauer Michael Beckmann Institute of Process Engineering and Environmental Technology Faculty of Mechanical Science and EngineeringTU Dresden01062 DresdenGermany

In this article,the binding forms of two lignite samples are determined by thermal desorption using a high-temperature *** mercury compound,such as HgCl2,has a specifc binding strength whose decomposition requires a certain thermal ***,the release of mercury from pure substances and lignite samples was analyzed in a high-temperature *** released mercury is determined with a Mercury Vapor *** obtained characteristic temperature range and peak of the mercury release were compared between lignite samples and mercury pure *** the lignite samples investigated,the binding form of mercury was then identifed as Humic *** organic compounds vaporize at lower *** half of the mercury bound in the lignite was already released at 350℃.Furthermore,the question arises whether mercury is already released during the grinding-drying process in the coal mill of a power *** two power plants,lignite samples were taken simultaneously at the feeder before entering the coal mill and at the dust line *** samples were analyzed for mercury *** results show that up to one third of the mercury was already released in the coal *** vaporized mercury enters the combustion chamber detached from the *** stated analysis methods and the results presented in this article contribute to the understanding of the mercury binding forms in *** also shows the potential of thermal coal pretreatment as a favorable alternative mercury separation technology to others such as activated carbon dosing.

关键词： Mercury binding forms Thermal desorption Mercury release Coal mill Coal pretreatment

Diatom-inspired Plastic Deformation Elements for Energy Absorption in Automobiles

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Journal of Bionic Engineering 2015年第4期12卷 613-623页

作者： christin.Hundertmark Rudiger Tinter Marc Ortelt Marcus J B Hauser Otto-von-Guericke University Magdeburg Institute of Experimental Physics Biophysics Group Universitatsplatz 2 39106 Magdeburg Germany Volkswagen AG Plastic Business Sector Postbox O11/1219 38436 Wolfsburg Germany

We report on a biomimetic approach for the construction of a deformation element in vehicles which absorbs energy in the case of lateral collisions. We aim at simultaneously maximising the energy absorption capacity of the component and mini- mising its weight. The examined deformation element, a crash-pad is inspired by the structure of a diatom which is known for its structural stability. As the natural counterpart, our crash pad is characterized by an undulated shape. The three undulations of the crash pad are of different height and provide for a sequential absorption of the impact energy. Compression tests were performed on the prototypes of the crash pad that were produced from different materials, namely a conventional talc reinforced poly- propylene and a natural fibre reinforced plastic. Compression tests revealed that the bioinspired crash pads performed better or equal than their technical counterpart. As required, the bioinspired components deformed continuously with the increase in deformation force. Since the differences in the properties of the used materials were small, the increased energy absorption properties were predominantly due to the structure of the biomimetic deformation element.

关键词： biomimetic approach deformation element side crash natural fibre reinforced plastic energy absorption diatoms

Protein Disulfide Isomerase 2 of Chlamydomonas reinhardtii Is Involved in Circadian Rhythm Regulation

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Molecular Plant 2013年第5期6卷 1503-1517页

作者： Anna Filonova Paul Haemsch christin.Gebauer Wolfram Weisheit Volker Wagner Institute of General Botany and Plant Physiology Friedrich-Schiller-Universitat Jena 07743 Jena Germany

Protein disulfide isomerases （PDIs） are known to play important roles in the folding of nascent proteins and in the formation of disulfide bonds. Recently, we identified a PDI from Chlamydomonas reinhardtii （CrPDI2） by a mass spectrometry approach that is specifically enriched by heparin affinity chromatography in samples taken during the night phase. Here, we show that the recombinant CrPDI2 is a redox-active protein. It is reduced by thioredoxin reductase and catalyzes itself the reduction of insulin chains and the oxidative refolding of scrambled RNase A. By immunoblots, we confirm a high-amplitude change in abundance of the heparin-bound CrPDI2 during subjective night. Interestingly, we find that CrPDI2 is present in protein complexes of different sizes at both day and night. Among three identified interac- tion partners, one （a 2-cys peroxiredoxin） is present only during the night phase. To study a potential function of CrPDI2 within the circadian system, we have overexpressed its gene. Two transgenic lines were used to measure the rhythm of phototaxis~ In the transgenic strains, a change in the acrophase was observed. This indicates that CrPDI2 is involved in the circadian signaling pathway and, together with the night phase-specific interaction of CrPDI2 and a peroxiredoxin, these findings suggest a close coupling of redox processes and the circadian clock in C. reinhardtii.

关键词： Chlamydomonas reinhardtii protein disulfide isomerase 2 circadian clock.

Scientific geodata infrastructures: challenges, approaches and directions

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International Journal of Digital Earth 2014年第7期7卷 613-633页

作者： Lars Bernard Stephan Mas Matthias Muller christin.Henzen Johannes Brauner Department of Geosciences Faculty of Environmental SciencesTechnische Universitat DresdenDresdenGermany

Based on various experiences in developing Geodata Infrastructures(GDIs)for scientific applications,this article proposes the concept of a Scientific GDI that can be used by scientists in environmental and earth sciences to share and disseminate their research results and related analysis *** GDI is understood as an approach to tackle the science case in Digital Earth and to further enhance e-science for environmental *** Scientific GDI to support the research community in efficiently exchanging data and methods related to the various scientific disciplines forming the basis of environmental studies poses numerous challenges on today’s GDI *** paper summarizes requirements and recommendations on the publication of scientific geospatial data and on functionalities to be provided in Scientific *** practices and open issues for governance and policies of a Scientific GDI are discussed and are concluded by deriving a research agenda for the next decade.

关键词： scientific geodata infrastructure sharing environmental models geospatial cyberinfrastructure e-science spatial data infrastructure

A decision framework for identifying models to estimate forest ecosystem services gains from restoration

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Forest Ecosystems 2016年第2期3卷 126-137页

作者： Zachary L. christin.Kenneth J. Bagstad Michael A. Verdone Earth Economics 107 N Tacoma Ave Tacoma WA 98403 USA. U.S. Geological Survey Geosciences & Environmental Change Science Center Box 25046 MS 980 Denver CO 80225 USA. International Union for the Conservation of Nature 1630 Connecticut Ave. NW #300 Washington DC 20009 USA.

Restoring degraded forests and agricultural lands has become a global conservation priority. A growing number of tools can quantify ecosystem service tradeoffs associated with forest restoration. This evolving ＂tools landscape＂ presents a dilemma： more tools are available, but selecting appropriate tools has become more challenging. We present a Restoration Ecosystem Service Tool Selector （RESTS） framework that describes key characteristics of 13 ecosystem service assessment tools. Analysts enter information about their decision context, services to be analyzed, and desired outputs. Tools are filtered and presented based on five evaluative criteria： scalability, cost, time requirements, handling of uncertainty, and applicability to benefit-cost analysis. RESTS uses a spreadsheet interface but a web-based interface is planned. Given the rapid evolution of ecosystem services science, RESTS provides an adaptable framework to guide forest restoration decision makers toward tools that can help quantify ecosystem services in support of restoration.

关键词： Decision support Ecosystem services Forest restoration Modeling Valuation Comparative toolsassessment

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Myelin-based inhibitors of oligodendrocyte myelination: clues from axonal growth and regeneration

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Neuroscience Bulletin 2013年第2期29卷 177-188页

作者： Feng Mei S.Y.christin.Chong Jonah R.Chan Department of Neurology Program in Neuroscience and the MS Research GroupUniversity of California

The differentiation of and myelination by oligodendrocytes （OLs） are exquisitely regulated by a series of intrinsic and extrinsic mechanisms. As each OL can make differing numbers of myelin segments with variable lengths along similar axon tracts, myelination can be viewed as a graded process shaped by inhibitory/ inductive cues during development. Myelination by OLs is a prime example of an adaptive process determined by the microenvironment and architecture of the central nervous system （CNS）. In this review, we discuss how myelin formation by OLs may be controlled by the heterogeneous microenvironment of the CNS. Then we address recent findings demonstrating that neighboring OLs may compete for available axon space, and highlight our current understanding of myelin-based inhibitors of axonal regeneration that are potentially responsible for the reciprocal dialogue between OLs and determine the numbers and lengths of myelin internodes. Understanding the mechanisms that control the spatiotemporal regulation of myelinogenic potential during development may provide valuable insight into therapeutic strategies for promoting remyelination in an inhibitory microenvironment.

关键词： differentiation myelin nogo-A LINGO-l semaphorin ephrin netrin-1

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