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The role of zonal flows in reactive fluid closures

Open Journal of Biophysics（生物物理学期刊） 2024年第3期 265页

作者： jan Helm

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Plasma Science and Technology 2018年第7期20卷 41-49页

作者： jan weiland Chalmers University of Technology and EURATOM-VR Association SE-41296 GothenburgSweden

We will give an overview of results obtained by our reactive fluid model. It is characterised as a fluid model where all moments with sources in the experiment are kept. Furthermore, full account is taken for the highest moments appearing in unexpanded denominators also including full toroidicity. It has been demonstrated that the strength of zonal flows is dramatically larger in reactive fluid closures than in those which involve dissipation. This gives a direct connection between the fluid closure and the level of excitation of turbulence. This is because zonal flows are needed to absorb the inverse cascade in quasi 2D turbulence. This also explains the similarity in structure of the transport coefficients in our model with a reactive closure in the energy equation and models which have a reactive closure because of zero ion temperature such as the Hasegawa-Wakatani model. Our exact reactive closure unifies several well-known features of tokamak experiments such as the L-H transition, internal transport barriers and the nonlinear Dimits upshift of the critical gradient for onset of transport. It also gives transport of the same level as that in nonlinear gyrokinetic codes. Since these include the kinetic resonance this confirms the validity of the thermodynamic properties of our model. Furthermore, we can show that while a strongly nonlinear model is needed in kinetic theory a quasilinear model is sufficient in the fluid description. Thus our quasilinear fluid model will be adequate for treating all relevant problems in bulk transport. This is finally confirmed by the reproduction by the model of the experimental power scaling of the confinement time Te ~ P-2/3. This confirms the validity of our reactive fluid model. This also gives credibility to our ITER simulations including the H-mode barrier. A new result is here, that alpha heating strongly reduces the slope of the H-mode barrier. This should significantly reduce the effects of ELM＇s.

关键词： turbulent transport improved mixing length estimates zonal flows toroidicity

Calculation of the Standard Model Parameters and Particles Based on a SU(4) Preon Model

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Ashtekar-Kodama Gravity as a Classical and Quantum Extension of Loop Quantum Gravity

Journal of Modern Physics（现代物理） 2024年第1期

作者： jan Helm

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西秦岭商丹缝合带寒武纪斜长花岗岩的成因机制——对原特提斯洋俯冲起始的启示

Journal of Modern Physics（现代物理） 2024年第6期 864页

作者： jan Helm

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岩石矿物学杂志 2024年第2期43卷 304-329页

作者：郭祺张建新毛小红武亚威中国地质科学院地质研究所北京100037 北京大学地球与空间科学学院北京100871

大洋斜长花岗岩是指分布在蛇绿岩或现今洋壳中的少量长英质侵入体,可形成在洋中脊及俯冲带等多种构造环境,虽然其在洋壳和蛇绿岩中所在体积很小,但对探究大洋岩石圈演化、俯冲起始及洋-陆转化机制具有重要意义。本文对北秦岭造山带西段... 详细信息

大洋斜长花岗岩是指分布在蛇绿岩或现今洋壳中的少量长英质侵入体,可形成在洋中脊及俯冲带等多种构造环境,虽然其在洋壳和蛇绿岩中所在体积很小,但对探究大洋岩石圈演化、俯冲起始及洋-陆转化机制具有重要意义。本文对北秦岭造山带西段商丹缝合带内新识别出的斜长花岗岩开展了岩石学、地球化学和锆石U-Pb年代学的综合研究。全岩地球化学结果指示花岗闪长岩具有高的SiO2、Al2O3含量以及较低的K2O、TiO2含量,属于低钾亚碱性、准铝质到弱过铝质的岩石。微量元素相对富Sr、贫Nb、Ta和Ti,具有平坦的稀土元素配分模式,是弧前环境中由俯冲板片在浅部层次部分熔融成因的大洋斜长花岗岩。3个斜长花岗岩样品分别记录了526±4 Ma、515±4 Ma和517±6 Ma的锆石U-Pb年龄,结合前人同时代的玻安岩、高镁安山岩的报道,西秦岭商丹缝合带保留有与伊豆-小笠原-马里亚纳(IBM)俯冲带相似的弧前岩石组合,这些弧前的玻安岩、高镁安山岩和斜长花岗岩表明商丹洋在早寒武世发生了洋壳的初始俯冲。结合区域地质资料,认为中央造山带可能在寒武纪发生了与IBM俯冲带规模相当的俯冲起始。

关键词：西秦岭商丹缝合带斜长花岗岩部分熔融俯冲起始

Comparative study of electrostatic sensors with circular and probe electrodes for velocity measurement of pulverised coal

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仪器仪表学报 2007年第11期28卷 1921-1926页

作者： Krabicka jan Department of Electronics University of Kent

This paper presents recent progress on the velocity measurement of pulverised coal in pneumatic pipelines using electrostatic sensors in combination with correlation signal processing techniques.A comparative study of electrostatic sensors with circular and probe electrodes was conducted on a 94 mm bore horizontal pipeline in a 4 MW *** advantages and limitations of both sensors are *** results demonstrate that both sensors are capable of providing pulverised coal velocity measurement with excellent repeatability and dynamic response.

关键词：电话无线电电子仪器技术性能

Grain Size Distribution of Soils within the Cordillera Blanca, Peru: An Indicator of Basic Mechanical Properties for Slope Stability Evaluation

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Journal of Mountain Science 2014年第3期11卷 563-577页

作者： jan NOVOTNY jan KLIME ARCADIS CZ a.s. Institute of Hydrogeology Engineering Geology and Applied Geophysics Charles University in Prague Albertov Department of Engineering Geology Institute of Rock Structure and Mechanics Academy of Sciences of the Czech Republic v.v.i

This paper presents results of a study on the mechanical properties of sandy and gravely soils within the Cordillera Blanca, Peru. The soils were divided into groups according to their origin(glacial, fluvial, or debris flow). The grain size distribution of forty three soil samples was used to classify the soils according to the scheme of the Unified Soil Classification System(USCS). These distributions have then been used to estimate shear strength and hydraulic properties of the soils. There are clear differences between the soils which reflect their divergent origins. The glacial soils normally fit within one of two distinctive groups according to the proportion of fines(Group A, 7%-21.5%; Group B, 21%-65%). The estimation of shear strength at constant volume friction angle and peak shear strength of the glacial sediments with low content of fines was made using published data relating to the measured shear strength characteristics of soils with similar origins and grain size distributions. The estimated values were supported by measurements of the angle of repose taken from fourteen samples from two moraines and by shear tests on samples from one locality. The results of the grain size distribution werealso used to estimate the average hydraulic conductivity using the empirical Hazen formula which results were verified by field infiltration tests at two localities.

关键词： Moraines Grain size distribution Shearstrength Hydraulic conductivity Cordillera Blanca Peru

A new GIS-compatible methodology for visibility analysis in digital surface models of earth sites

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Geoscience Frontiers 2021年第4期12卷 21-33页

作者： Katerina Ruzickova jan Ruzicka jan Bitta VSB–Technical University of Ostrava Czech Republic

As a GIS tool,visibility analysis is used in many areas to evaluate both visible and non-visible *** analysis builds on a digital surface model describing the terrain morphology,including the position and shapes of all objects that can sometimes act as visibility ***,some barriers,for example vegetation,may be permeable to a certain *** extensive research and use of visibility analysis in different areas,standard GIS tools do not take permeability into *** article presents a new method to calculate visibility through partly permeable *** method is based on a quasi-Monte Carlo simulation with 100 iterations of visibility *** iteration result represents 1%of vegetation permeability,which can thus range from 1%to 100%visibility behind vegetation *** main advantage of the method is greater accuracy of visibility results and easy implementation on any GIS *** incorporation of the proposed method in GIS software would facilitate work in many fields,such as architecture,archaeology,radio communication,and the military.

关键词： Digital surface model Visibility analysis Topographic data processing Obstacle object Permeability

The effect of Tyrophagus putrescentiae on Fusarium poae transmission and fungal community in stored barley in a laboratory experiment

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Insect Science 2014年第1期21卷 65-73页

作者： jan Hubert Marta Nesvorna jan Kopecky Crop Research Institute Praha 6 Czech Repubfic

The effect of Tyrophagus putrescentiae on Fusarium poae transmission and fungal community composition was studied in nonsterile barley grain. The experiments included following treatments： control barley without mites; barley containing l0 or 50 mites without preincubation on E poae （Tpl0 and TpS0）; barley containing 10 or 50 mites after preincubation on E poae （FTp 10 and FTp50）. The number of mites, suc cessful transfer of E poae, and changes in the fungal communities were examined after 21 d of experiment. Increase of deoxynivalenol （DON） content in the barley was chosen as a criterion of successful Epoae transfer. The preincubation of T. putrescentiae on Epoae increased DON level approximately to 800 and 300μg/kg of grain for FTpl0 and FTpS0, respectively. T. putrescentiae population growth in FTpl0 was lower than in Tpl0, while no difference was found between FTp50 and Tp50. Fungal communities were compared by amplification, cloning and sequencing of ITS fragments, and operational taxonomic units （OTU） analysis. The OTU analysis did not support the transfer ofF. poae via mites. From the analyzed clones, only 13 cloned sequences clustered with E poae in an OTU defined at distance level 0.07. The related clones originated from FTpl0, Tpl 0, Tp50 and control treatments, but not from FTp50. However, the presence of E poae in FTp50 was confirmed by PCR amplification with specific primers. The observation may be explained by different effect of mite population density, that is, in the high density, （FTp50 treatment） the fungus was overgrazed, while the lower population density （FTp 10） supported E poae transfer.

关键词： barley deoxinivalenol (DON) Fusariumpoae mites mycotoxin storage

Stability Problems in Road and Pipeline Constructions and Their Mitigation——Examples from Sakhalin and Azerbaijan

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Journal of Mountain Science 2011年第2期8卷 307-313页

作者： NOVOTNY jan ARCADIS Geotechnika a.s. Charles University in Prague Faculty of Natural Science

The paper gives two examples of larger construction projects with typical stability problems. The first example is from Sakhalin Island in the Russian Far East. It is connected with a construction of oil and gas pipelines through the mountainous terrain in Makarov region. The region has an active geotectonic history and is highly affected by uncontrolled erosion and extensive landslips. Basic principles of landslide hazard mitigation are presented. The second example is from a motorway construction in Azerbaijan. This motorway leads from Baku to Russia through a seismo-tectonically active area at the toe of Caucasian mountains and in some places is situated in deep cuts at the toe of high slopes. This unsuitable routing, together with seismic activity, led to a slope stability failure of a slope affected by recent tectonic movements near the village of Devechi. Stability conditions and designed remedy measures are presented.

关键词： Stability problems Roads Pipelines Mitigation Sakhalin Azerbaijan