检索结果-南通市图书馆

UNIFORM SUPERCONVERGENCE OF A FINITE ELEMENT METHOD WITH EDGE STABILIZATION FOR CONVECTION-DIFFUSION PROBLEMS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2010年第1期28卷 32-44页

作者： sebastian Franz Torsten Linβ Hans-Grg Roos sebastian Schiller Department of Mathematics and Statistics University of Limerick Institut für Numerische Mathematik Technische Universitt Dresden

In the present paper the edge stabilization technique is applied to a convection-diffusion problem with exponential boundary layers on the unit square, using a Shishkin mesh with bilinear finite elements in the layer regions and linear elements on the coarse part of the mesh. An error bound is proved for ‖πu-u^h‖Е, where πu is some interpolant of the solution u and uh the discrete solution. This supercloseness result implies an optimal error estimate with respect to the L2 norm and opens the door to the application of postprocessing for improving the discrete solution.

关键词： Convection-diffusion problems Edge stabilization FEM Uniform convergence Shishkin mesh.

Sufficient Conditions for Maximally Edge-connected and Super-edge-connected Digraphs Depending on the Size

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2019年第12期35卷 1861-1870页

作者： sebastian MILZ Lutz VOLKMANN Lehrstuhl Ⅱ für Mathematik RWTH Aachen University

Let D be a finite and simple digraph with vertex set V(D).The minimum degreeδof a digraph D is defined as the minimum value of its out-degrees and its *** D is a digraph with minimum degreeδand edge-connectivity λ,then λ≤δ.A digraph is maximally edge-connected ifλ=δ.A digraph is called super-edge-connected if every minimum edge-cut consists of edges incident to or from a vertex of minimum *** this note we show that a digraph is maximally edge-connected or super-edge-connected if the number of arcs is large enough.

关键词： Digraphs edge-connectivity maximally edge-connected digraphs super-edge-connected digraphs

The German Energiewende and its roll-out of renewableenergies： An economic perspective

在线全文

学校读者我要写书评

暂无评论

Frontiers in Energy 2017年第2期11卷 126-134页

作者： sebastian KREUZ Felix MUSGENS Faculty of Mechanical Engineering Electrical and Energy SystemsBrandenburg University of Technology 03046 Cottbus Germany

This paper gives a short overview of the German Energiewende, i.e. the transition of a large and mostly thermal electricity system towards electricity generation from renewable energy source. It discusses both, the motivation of the transitions as future goals and current status. Furthermore, it gives an in-depth view into the changes in economic costs for society as well as electricity price effects, especially for average private households and industrial consumers. It also discusses the benefits of the promotion of renewable energies in Germany.

关键词： electricity system renewable energy cost-benefit analysis

Interaction phenomena between liquid droplets and hot particles—Captured via high-speed camera

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2009年第4期7卷 260-263页

作者： sebastian Gehrke Karl-Ernst Wirth Institute of Particle Technology Cauerstrasse 4Erlangen 91058Germany

The interaction of evaporating droplets and hot catalyst particles plays a major role in heterogeneously catalysed reactions. The liquid feed is injected into a gas-solid flow and is mixed with the catalyst. The interaction phenomena determine the evaporation time which should be minimised to keep the reactor vessel small. First measurements with a bed of fixed hot FCC-particles （fluid catalytic cracking） and two model fluids have been conducted. The interactions of ethanol and water droplets with the hot bed surface were captured via a high-speed camera. While the ethanol droplet developed a stable steam cushion due to Leidenfrost phenomena, water showed intense interaction and steam explosions which induced repulsion and atomisation of the droplet.

关键词： Particle-droplet-interaction Leidenfrost phenomenon Direct heat transfer Liquid-feed-injection

Pharmacological blockage of CYP2E1 and alcohol-mediated liver cancer: is the time ready?

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Cancer Research 2013年第3期25卷 269-271页

作者： sebastian Mueller Department of Medicine and Alcohol Research Center Salem Medical Center University of Heidelberg

Chronic alcohol consumption is a major risk factor worldwide affecting significantly both mortality and years of life lost （YLL）（1）. Ca. 5% of the western world show risky alcohol consumption and in some countries such as China a regional yearly increase of alcohol consumption of over 400% has been observed recently （2,3）. The liver is the major target organ of alcohol. According to the recently published ＇Global Burden of Disease Study 2010, liver cirrhosis and liver cancer are ranked at position 12 and 16 in the global deaths statistics （1）. Thus, in 2010, ca. 1 million people died from liver cirrhosis with one third directly attributable to alcohol. This is a considerable number when comparing with coronary heart disease with 7 million deaths and the leading cause of mortality. In central Europe, liver cirrhosis even ranks at the fourth position in YLL. Hepatocellular cancer （HCC） is now the most common fatal complication of patients with alcoholic cirrhosis. Moreover, it shows the second fastest increase of all tumors worldwide after kidney tumors and alcohol-associated HCC ranks on third position after HCCs caused by viral hepatitis B and C.

关键词： CYP Pharmacological blockage of CYP2E1 and alcohol-mediated liver cancer is the time ready time

The impact of dielectrics on the electrical capacity, concentration, efficiency ozone generation for the plasma reactor with mesh electrodes

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2018年第8期20卷 89-95页

作者： Ernest GNAPOWSKI sebastian GNAPOWSKI Jaroslaw PYTKA University College of Enterprise and Administration in Lublin Bursaki 12 20-150 Lublin Poland Fundamentals of Technology Faculty Lublin University of Technology ul. Nadbystrzycka 38 20-618 Lublin Poland Faculty of Mechanical Engineering Lublin University of Technology ul. Nadbystrzycka 36 20-618 Lublin Poland

This paper presents experimental results concerning the effect of dielectric type on ozone concentration and the efficiency of its generation in plasma reactor with two mesh *** types of dielectric solid were used in the study; glass, micanite and Kapton insulating foil. The experiments were conducted for voltage ranges from 2.3 to 13 k V. A plasma reactor equipped with two 0.3×0.3 mm^2 mesh electrodes made of acid resistant AISI 304 mesh was used in the experiments. The influence of the dielectric type on the concentration and efficiency of ozone generation was described. The resulting maximum concentration of the ozone was about 2.70–9.30 g O3 m^-3, depending on the dielectrics used. The difference between the maximum and the minimum ozone concentration depends on the dielectric used,this accounts for 70% at the variance. The reactor capacity has also been described in the paper; total Ct and dielectric capacitance Cd depending on the dielectric used and its thickness.

关键词： ozone generation efficiency dielectric mesh electrode ozone generator electrical capacity

Robustness analysis metrics for worldwide airport network：A comprehensive study

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2017年第2期30卷 500-512页

作者： Sun Xiaoqian Volker Gollnick sebastian Wandelt School of Electronic and Information Engineering Beihang University 100083 Beijing China Beijing Key Laboratory for Network-based Cooperative A TM Beijing 100083 China Beijing Laboratory for General Aviation Technology Beijing 100083 China Institute of Air Transportation Systems German Aerospace Center Blohmstrasse 18 21079 Hamburg Germany

Robustness of transportation networks is one of the major challenges of the 21 st *** paper investigates the resilience of global air transportation from a complex network point of view,with focus on attacking strategies in the airport network,i.e.,to remove airports from the system and see what could affect the air traffic system from a passenger＇s ***,we identify commonalities and differences between several robustness measures and attacking strategies,proposing a novel notion of functional robustness：unaffected passengers with *** apply twelve attacking strategies to the worldwide airport network with three weights,and evaluate three robustness *** find that degree and Bonacich based attacks harm passenger weighted network *** evaluation is geared toward a unified view on air transportation network attack and serves as a foundation on how to develop effective mitigation strategies.

关键词： Air transportation systems resilience Airport network Attacking strategy Robustness measure

Exploiting global information in complex network repair processes

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2017年第3期30卷 1086-1100页

作者： Tianyu WAng Jun ZHAng sebastian WANDELT School of Electronic and Information Engineering Beihang University 100083 Beijing ChinaBeoing Key Laboratory Jor Network-based Cooperative ATM 100083 Beijing China

Robustness of complex networks has been studied for decades,with a particular focus on network *** on network repair,on the other hand,has been conducted only very lately,given the even higher complexity and absence of an effective evaluation metric.A recently proposed network repair strategy is self-healing,which aims to repair networks for larger components at a low cost only with local *** this paper,we discuss the effectiveness and efficiency of self-healing,which limits network repair to be a multi-objective optimization problem and makes it difficult to measure its *** leads us to a new network repair evaluation *** the time complexity of the computation is very high,we devise a greedy ranking *** on both real-world and random networks show the effectiveness of our new metric and repair *** study contributes to optimal network repair algorithms and provides a gold standard for future studies on network repair.

关键词： Complex network Global information Greedy ranking Optimality Self-healing

Experimental and computational analysis of the coolant distribution considering the viscosity of the cutting fluid during machining with helical deep hole drills

在线全文

学校读者我要写书评

暂无评论

Advances in Manufacturing 2022年第2期10卷 235-249页

作者： Ekrem Oezkaya sebastian Michel Dirk Biermann Institute of Machining Technology Dortmund University of Technology(TU Dortmund)Dortmund 44227Germany

An experimental analysis regarding the distribution of the cutting fluid is very difficult due to the inaccessibility of the contact zone within the bore ***,suitable simulation models are necessary to evaluate new tool designs and optimize drilling *** this paper the coolant distribution during helical deep hole drilling is analyzed with high-speed *** particles are added to the cutting fluid circuit bya developed high-pressure mixing *** the evaluation of suitable particle size,particle concentration and coolant pressure,a computational fluid dynamics(CFD)simulation is validated with the experimental *** comparison shows a very good model quality with a marginal difference for the flow velocity of 1.57%between simulation and *** simulation considers the kinematic viscosity of the *** results show that the fluid velocity in the chip flutes is low compared to the fluid velocity at the exit of the coolant channels of the tool and drops even further between *** velocity and the flow pressure directly at the cutting edge decrease to such an extent that the fluid cannot generate a sufficient cooling or *** the CFD simulation a deeper understanding of the behavior and interactions of the cutting fluid is *** on these results further research activities to improve the coolant supply can be carried out with great potential to evaluate new tool geometries and optimize the machining process.

关键词： Computational fluid dynamics(CFD)analysis:Viscosity-Tracermicro particles Fluidbehavior Helical deep hole drilling