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Active protection of work area against explosion of dust-gas mixture

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International Journal of Coal Science & Technology 2021年第4期8卷 674-684页

作者： Zbigniew Szkudlarek sebastian Janas KOMAG Institute of Mining Technology 44-101 GliwicePoland

Potentially explosive atmosphere can occur not only in the production systems of the food,energy,chemical and petrochemical industries but also in the production processes of the mining ***,vapours,mists and dusts arise can escape in an uncontrolled way during production,processing,transportation and storage of flammable *** combination with oxygen,they create explosive atmospheres that,if ignited,lead to an explosion causing catastrophic damage to peopled lives and *** protect against the results of hazardous dust-gas mixtures explosions in a confined work space,where employees can stay,various control and protection mechanisms are used in the form of an active explosion-proof *** article presents the results of tests on an active system for limiting the effects of ignition of gas and/or dust based on a highly efficient explosion suppression system-equipped with an ignition detection system,high-pressure fire extinguisher and a power supply and trigger *** powder was used as the explosive charge and sodium bicarbonate as the suppressive *** of the effectiveness of the active explosion suppression system were carried out on two devices:a small-size dry dust collector and a zone extinguishing system adapted for direct explosion suppression in closed working *** both cases,the explosion suppression process took place through the action of extinguishing powder blown out of the fire extinguisher after membrane perforation by compressed combustion products.

关键词： Gas hazard Explosive dust Suppression of explosion Safety of work area

Micro-Task Processing in Heterogeneous Reconfigurable Systems

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Journal of Computer Science & Technology 2005年第5期20卷 624-634页

作者： sebastian Wallner Department of Distributed Systems Technical University of Hamburg-Harburg Schwarzenbergstrasse 95 D-21073 Hambur9 Germany

New reconfigurable computing architectures are introduced to overcome some of the limitations of conventional microprocessors and fine-grained reconfigurable devices （e.g., FPGAs）. One of the new promising architectures axe Configurable System-on-Chip （CSoC） solutions. They were designed to offer high computational performance for real-time signal processing and for a wide range of applications exhibiting high degrees of parallelism. The programming of such systems is an inherently challenging problem due to the lack of an programming model. This paper describes a novel heterogeneous system architecture for signal processing and data streaming applications. It offers high computational performance and a high degree of flexibility and adaptability by employing a micro Task Controller （mTC） unit in conjunction with programmable and configurable hardware. The hierarchically organized architecture provides a programming model, allows an efficient mapping of applications and is shown to be easy scalable to future VLSI technologies. Several mappings of commonly used digital signal processing algorithms for future telecommunication and multimedia systems and implementation results axe given for a standard-cell ASIC design realization in 0.18 micron 6-layer UMC CMOS technology.

关键词： system-on-chip reconfigurable heterogeneous architectures configuration instructions descriptors parallel processing system signal processing

Does pressure cause liver cirrhosis? The sinusoidal pressure hypothesis

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World Journal of Gastroenterology 2016年第48期22卷 10482-10501页

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

Independent of their etiology, all chronic liver diseases ultimately lead to liver cirrhosis, which is a majorhealth problem worldwide. The underlying molecular mechanisms are still poorly understood and no efficient treatment strategies are available. This paper introduces the sinusoidal pressure hypothesis(SPH), which identifies an elevated sinusoidal pressure(SP) as cause of fibrosis. SPH has been mainly derived from recent studies on liver stiffness. So far, pressure changes have been exclusively seen as a consequ-ence of cirrhosis. According to the SPH, however, an elevated SP is the major upstream event that initiates fibrosis via biomechanic signaling by stretching of perisinusoidal cells such as hepatic stellate cells or fibroblasts(SPH part?Ⅰ: initiation). Fibrosis progression is determined by the degree and time of elevated SP. The SPH predicts that the degree of extracellular matrix eventually matches SP with critical thresholds > 12 mmH g and > 4 wk. Elevated arterial flow and final arterialization of the cirrhotic liver represents the self-perpetuating key event exposing the low-pressure-organ to pathologically high pressures(SPH part?Ⅱ: perpetuation). It also defines the "point of no return" where fibrosis progression becomes irreversible. The SPH is able to explain the macroscopic changes of cirrhotic livers and the uniform fibrotic response to various etiologies. It also opens up new views on the role of fat and disease mechanisms in other organs. The novel concept will hopefully stimulate the search for new treatment strategies.

关键词： liver stiffness Stretch force Sinusoidal pressure hypothesis liver cirrhosis Hepatic arterial buffer response biomechanics Arterialization Hepatic stellate cells Fibroblasts cellular and intercellular mechano-signaling

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

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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.

Interplay between microstructural evolution and tribo-chemistry during dry sliding of metals

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Friction 2019年第6期7卷 637-650页

作者： Philipp GGRÜTZMACHER sebastian RAMMACHER Dominic RATHMANN Christian MOTZ FrankMÜCKLICH sebastian SUAREZ Chair of Functional Materials Saarland UniversityCampus D3.3Saarbrücken 66123Germany Chair of Experimental Methodology of Material Science Saarland UniversityCampus D2.2Saarbrücken 66123Germany

Understanding the microstructural and tribo-chemical processes during tribological loading is of utmost importance to further improve the tribological behavior of metals. In this study, the friction, wear and tribo-chemical behavior of Ni with different initial microstructures(nanocrystalline, bi-modal, coarse-grained) is investigated under dry sliding conditions. In particular, the interplay be-tween frictional response, microstructural evolution and tribo-oxidation is considered. Friction tests are carried out using ball-on-disk experiments with alumina balls as counter-bodies, varying the load between 1 and 5 N. The microstructural evolution as well as the chemical reactions beneath the samples’ surface is investigated by means of cross-sections. The samples with finer microstructures show a faster run-in and lower maximum values of the coefficient of friction(COF) which can be attributed to higher oxidation kinetics and a higher hardness. It is observed that with increasing sliding cycles, a stable oxide layer is formed. Furthermore, initially coarse-grained samples show grain refinement, whereas initially finer microstructures undergo grain coarsening converging towards the same superficial grain size after 2,000 sliding cycles. Consequently, the experimental evidence supports that, irrespective of the initial microstructure, after a certain deformation almost identical steady-state COF values for all samples are achieved.

关键词： dry sliding microstructural analysis tribo‐oxidation wear

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

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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

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

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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

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

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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

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

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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