Wyniki wyszukiwania - BazTech

1

Relations between ion signal and flame propagation in cylinder of a rapid compression machine

Fiedkiewicz Łukasz, Pielecha Ireneusz

Combustion Engines

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2019

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R. 58, nr 4

264--268

EN

Internal combustion engine diagnostics using traditional methods of cylinder pressure signal processing limits the amount of information available about the combustion process. It is necessary to conduct research in order to obtain more precise information - in-creasing the combustion process diagnosis potential. One such suggestion is the use of an ionization signal and an attempt to link it to the flame development during combustion of gaseous fuels. The article attempts to identify such a relationship using a rapid compression machine due to optical access it provides to the combustion chamber. As a result of the research, the relationships between the ionization voltage (chemical and thermal) of the first combustion phase and the corresponding flame development rates were determined. A relatively high coefficient of determination value was obtained for both relations, which indicates the possibility of obtaining diagnostic information about the combustion process from the ionization signal.

2

Nanopory : budowa, właściwości, modele, zastosowania

Stachiewicz A., Molski A.

Wiadomości Chemiczne

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2013

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[Z] 67, 3-4

277--302

EN

Nanopores are small (1–100 nm diameter) holes/channels formed in biological membranes (Fig. 1) or fabricated in synthetic materials (Fig. 2). Permeation of ions and small molecules through nanopores is common in biological systems. The first experiments where nanopores were used as single-molecule sensors were performed in the 90s [1, 2]. The detection principle is based on a monitoring of an ionic current passing through a nanopore as an electric field is applied across the membrane. Electrically charged particles (e.g. DNA ) move in the electric field and block the ionic current as they pass through the nanopore. A sudden drop of the ionic current signals a single-molecule translocation event (Fig. 3–5). Nanopore sensors can give an information about the analyte: its size, structure and bonds stability. Today, a major topic of interest is the possibility of nanopore DNA sequencing. In this work we present an introduction to nanopore technology and to current research related to potential nanopore applications. First, we describe biological and synthetic nanopores: their structure and methods of fabrication. Next, different modes of nanopore experiments are presented. In the third section, we focus on theoretical models and simulations of nanopores. Finally, we present future perspectives for applications with particular reference to DNA sequencing.

3

Numerical study of ionic current in a dielectric liquid layer subjected to square wave voltage

Derfel G., Opioła P.

Scientific Bulletin. Physics / Lodz University of Technology

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2009

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Vol. 30

19-28

EN

Ionic current flowing in a thin layer of dielectric liquid under the action of square wave voltage was studied numerically. Quasi-blocking electrodes and equal mobilities of unions and cations were assumed. Field dependent dissociation and recombination were taken into account. The spatial distributions of ion concentrations and the ionic current density during a single voltage cycle were calculated as functions of time. A bump of the current was observed at suitably high voltage, low ion content and low frequency. This effect resulted from redistribution of ions which occurred in the whole layer. Two gradually diffusing groups of ions wandering across the layer, one formed by cations and the other formed by anions, could be distinguished. There was no unambiguous relationship between the moment at which the bump occurred and the value of ions mobility.

PL

Zbadano numerycznie prąd jonowy płynący w cienkiej warstwie cieczy dielektrycznej poddanej działaniu zewnętrznego napięcia w formie fali prostokątnej, przyłożonego między elektrodami silnie blokującymi. Założono równe ruchliwości anionów i kationów. Uwzględniono procesy dysocjacji i rekombinacji. Obliczono przestrzenne rozkłady koncentracji jonów oraz gęstość prądu jonowego w ciągu pojedyńczego okresu zmian napięcia jako funkcje czasu. Stwierdzono wystąpienie maksimum prądu pojawiającego się przy odpowiednio dużej amplitudzie napięcia, niskiej koncentracji jonów i niskiej częstości. Zjawisko to spowodowane było zmianami rozkładu ładunku w warstwie. Wykazano, ze czas wystąpienia maksimum prądowego nie może być jednoznacznie powiązany z ruchliwością jonów.

4

Parametry struktury modelowych materiałów porowatych

Łukowski J., Kołodziej J.

Zeszyty Naukowe. Mechanika / Akademia Techniczno-Rolnicza w Bydgoszczy

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2002

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Z. 53(241)

129-137

PL

Przedstawiono wyniki modelowania analityczno-numerycznego przepływu prądu jonowego przez układ złożony z wiązki równoległych prętów zanurzonych w elektrolicie wykorzystując metodę kolokacji brzegowej. Analizowano przepływ prądu jonowego wzdłuż, oraz w poprzek prętów. Wyznaczono parametry opisujące architekturę wewnętrzną układu: współczynnik uformowania i krętość w funkcji porowatości dla trzech różnych regularnych konfiguracji prętów.

EN

The paper presents the results of analytic-numerical modeling of ionic current flow through an array composed of a bundle of parallel rods, submerged in electrolyte, using the boundary collocation method. The flow o ionic current along and across the rod was analyzed. The parameters were determined, describing internal architecture of the array: formation coefficient and tortuousity relative to three varied regular rod configurations.