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Modeling electromagnetic nanostructures and experimenting with nanoelectric elements to form periodic structures

Steinbauer Miloslav, Pernica Roman, Zukal Jiri, Kadlec Radim, Bachorec Tibor, Fiala Pavel

Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska

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2020

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T. 10, nr 4

4--14

EN

We discuss the numerical modeling of electromagnetic, carbon-based periodic structures, including graphene, graphane, graphite, and graphyne. The materials are suitable for sub-micron sensors, electric lines, and other applications, such as those within biomedicine,photonics, nano-and optoelectronics; in addition to these domains and branches, the applicability extends into, for example, microscopic solutions for modern SMART elements. The proposed classic and hybrid numerical models are based on analyzing a periodic structure with a high repeatability, and they exploitthe concept of a carbon structure having its fundamental dimension in nanometers. The models can simulate harmonic and transient processes;are capable of evaluating the actual random motion of an electric charge as a source of spurious signals; and consider the parameters of harmonic signal propagation along the structure. The results obtained from the analysis are utilizable for the design of sensing devices based on carbon periodic structures andwere employed in experiments with a plasma generator.The aim is to provide a broader overview of specialized nanostructural modeling, or, more concretely, to outline a model utilizable in evaluating the propagation of a signal along a structure’s surface.

PL

W artykule omówiony został procesnumerycznegomodelowaniaelektromagnetycznych, węglowych struktur okresowych, w tym grafenu, grafanu, grafitu i grafinu. Materiały te nadają się do czujników submikronowych, przewodów elektrycznych i innych zastosowań, takich jak biomedycyna, fotonika, nano-i optoelektronika.Oprócz tych dziedzin i gałęzi przemysłu, zastosowanie materiałów pokrywa się także na przykład z mikroskopijnymirozwiązaniamidla nowoczesnych elementów SMART. Proponowane klasyczne i hybrydowe modele numeryczneopierają się na analizie okresowej struktury o wysokiej powtarzalności i wykorzystują koncepcję struktury węglowej o podstawowym wymiarze w nanometrach. Modele mogą symulować procesy harmoniczne i przejściowe,potrafią ocenić rzeczywisty losowy ruch ładunku elektrycznego jako źródła fałszywych sygnałówi uwzględniająparametry propagacji sygnału harmonicznego wzdłuż konstrukcji. Rezultaty uzyskane w wyniku analizy można wykorzystać do projektowania czujników opartych na węglowych strukturach okresowych oraz do eksperymentów z generatorem plazmy. Celem jest zapewnienie szerszego przeglądu specjalistycznego modelowania nanostrukturalnego lub, bardziej konkretnie, zarysumodelu nadającego się do oceny propagacji sygnału wzdłuż powierzchnistruktury.

2

Experimental Modeling to Facilitate Removal of Inclusion Contaminants from the Contact Surface in Transversal Extrusion Processes

Skorulski G., Piwnik J., Hościło B.

Archives of Foundry Engineering

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2014

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Vol. 14, iss. 1 spec.

209--212

EN

The paper presents experimental optimization of geometrical conditions regarding the shape of billet’s end pieces in the extrusion process of aluminum alloys. The experiments were performed using appropriately pre-treated plasticine as a substitute material. A special test stand was built using a Plexiglass die in order to make it possible to conduct observations and measurements of the modeled contamination surface. To find the best solution, a great number of shape variants of the billets and of their heating temperatures were experimentally analyzed. An attempt was made to find such a solution that could not only resolve the issue of the removal of contaminants from the contact surface of the pre- heated billets but also develop the least complicated technology of billet fabrication. The test results show how to develop the design process and production technology and also offer advice how to improve the quality of the produced profiles. Finally the authors recommend such a shape for the billets that will ensure effective removal of contaminants from the contact surfaces.

3

The Influence of Segregation Phenomena on Quality of Product in Extrusion Process

Skorulski G., Piwnik J., Baranowski P.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 3 spec.

251--254

EN

The segregation phenomena and formation of agglomerate have the basic influence on structure of the final product. The aim of this work is analyzing the phenomena of segregation in semi-solid extrusion process, using several kind of substitute materials, which can simulate the thixotrophic fluid behavior and displacement of solid particles. The experimental researches are made to investigation of segregation in the near-wall layers and the formation of agglomerate. Especially, the distribution of the solid particles at the end of extrusion process have been taken into consideration. Theoretical criteria describe the critical value of the energy liberated at the surfaces by the action of forces depends on the temperature, the pressure, the yield stress and the physical state and degree of intimacy of the contacting surfaces. The theory has been tested experimentally using a silicon polymer as a substitute material. Experimental stand with a Plexiglass die was prepared, such that the velocity fields at the surfaces could be observed and measured during plastic flow, allowing the empirical coefficients in the mathematical formulation to be estimated. On the basis of the theory and experiment an optimal die chamber was designed for a die with a complex shape.

4

The Favourable Choice of the Shape of Billet's Contact Surface to Quality of Extruded Aluminium Profiles

Skorulski G., Piwnik J., Baranowski P.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 3 spec.

245--250

EN

The theoretical and experimental method of optimization the aluminium billet’s contact surface during extrusion have been presented in this paper. The theoretical assumption, based on welding criteria, have been confirmed by experimental researches. The technique of measurement has been shown as well. Experiments are made using plasticine as a substiute material. Some kind of different variants have been investigated. The theory and experiments have been provided to optimize the modeling shape and may help in design and technology. The theory has been tested experimentally using a plasticine as a substitute material and a plexiglass die such that the velocity fields at the surfaces could be observed and measured during plastic flow, allowing the empirical coefficients in the mathematical formulation to be estimated. On the basis of the theory and experiments an optimal billet’s contact surface was proposed.

5

Metematiceskoe i eksperimental'noe modelirovanie dvizenia polidispersnyh sred v kanalah sloznoj geometrii

Slobodkina F. A.

Prace Instytutu Górnictwa Naftowego i Gazownictwa

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2002

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nr 116 wyd. konferencyjne

97--101

6

Experimental modeling of large scale gas fuel injector for IC piston engines

Bocian P., Wojciechowski J., Rychter T.

Research Bulletin / Warsaw University of Technology, Institute of Aeronautics and Applied Mechanics

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1998

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nr 8

81-84

EN

Supplying 1C piston engines with gaseous fuels is one of well known approaches to reduce the content of polluting components in exhaust gases. One of methods for gaseous fuel supply considered is a high-pressure direct gas injection, which is currently studied in a number of laboratories. The successful application of this method requires the proper organisation of the combustion system and particularly - the careful treatment of the gas injection process and its mixing with the surrounding air. Very important is also the location of the choice of the ignition point in order to assure repeatable combustion initiation. The mixing process strongly depends on the shape and the direction of the injected gas which, in turn, depends on the injector tip geometry. The main objective of the presented experimental analysis is to determine the best of the gaseous fuel single-nozzle injector, would be able to assure the proper mixing of the gas with air. The investigations were performed under "cold" conditions with the use of the model gas injector in geometrical scale 10:1. The conventional-like form of the nozzle was with annular gas flow area created by the gap between the pintle and the nozzle wall. The element as well as experimental conditions be easily changed in the wide range This made it possible to select jet geometry (the form, length and convergence angle of the pintle, nozzle outlet and divergence angle etc.). It also for the longitudinal vorticity control: from axial flow to the flow with strong velocity component, or any form. The injection gas pressure was 0.5 MPa, which allowed for the rough simulation engine conditions, for a large spectrum of flow geometries (pintle, nozzle, vorticity). The CO2 was as a working medium. There were used: flow visualisation by schlieren method, the hot-wire technique for determination of velocity especially designed hot-wire probe and the infrared energy apparatus to measure - respectively - the high and low or very low injected gas local concentration. Some interesting injector configurations were chosen for posterior measurements of velocity field in the free circular jet of gas past the injector. The study allowed for drawing the optimal schema of the single-nozzle gas fuel injector, which has become the base for the combustion tests in a normal-scale injection system.