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Wyszukujesz frazę "molecular clusters" wg kryterium: Temat

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    Wyświetlanie 1-4 z 4
    Tytuł:
    The role of molecularly ordered structures in energy transport enhancement during combustion process : a new conception of a reaction mechanism of fuel components oxidation
    Autorzy:
    Białecki, T.
    Dzięgielewski, W.
    Gawron, B.
    Kaźmierczak, U.
    Kulczycki, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/245703.pdf
    Data publikacji:
    2018
    Wydawca:
    Instytut Techniczny Wojsk Lotniczych
    Tematy:
    molecular clusters
    turbojet engine
    butanol
    combustion process
    carbon oxide emission
    Opis:
    This article presents the results of investigations focused on the role of molecularly ordered structures (molecular clusters) on combustion process. The proposed new mechanism of the reactions initiation takes into account the role of molecular clusters in energy (heat and energy of electrons emitted by the surface of the walls of combustion chamber) conductivity regulation. Literature survey shows that molecular clusters created by aromatic hydrocarbons are responsible for particulate matter. The combustion process itself is not uniform in whole combustion chamber. Such diversity, caused mainly by heterogeneous thermal state of combustion chamber is recognized as significant reason to create various products of combustion including carbon oxides, carbon dioxides and nitrogen oxides. Jet fuel and its blends with n-butanol and biobutanol in concentration from 10 to 75 % (V/V) were subjected to laboratory tests. Such blends were also tested on the test rig with a miniature turbojet engine – MiniJETRig. Engine operating parameters and carbon oxide emission were measured. The relations between electrical conductivity and parameters of engine test (e.g. temperature in selected points in combustion chamber) were assessed. Engine tests were carried out according to specific profile of engine test, which models different engine operating modes. The results of experimental investigations, shown in the article, initially confirm the proposed mechanism of the oxidation reactions initiation during combustion process.
    Źródło:
    Journal of KONES; 2018, 25, 4; 17-24
    1231-4005
    2354-0133
    Pojawia się w:
    Journal of KONES
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The influence of the chemical structure of synthetic hydrocarbons and alcohols on the lubricity of CI engine fuels and aviation fuels
    Wpływ struktury chemicznej syntetycznych węglowodorów i alkoholi na smarność paliw do silników ZS i silników lotniczych
    Autorzy:
    Kulczycki, A.
    Dzięgielewski, W
    Ozimina, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/187785.pdf
    Data publikacji:
    2017
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    fuels
    fuel lubricity
    synthetic hydrocarbons
    alcohols
    molecular clusters
    paliwa
    smarność paliw
    syntetyczne węglowodory
    klastry molekularne
    Opis:
    The paper covers the mechanism of lubrication layer formation by fuels containing synthetic hydrocarbons and alcohols. Development of alternative fuels containing FAME, alcohols, and synthetic hydrocarbons has increased the interest in the mechanism of lubrication of fuelling systems parts. Fuel lubricity tests have been conducted using the HFRR and BOCLE testing rigs. Fuels under testing, both for CI engines and for aviation turbine ones, contained synthetic components: saturated hydrocarbons both of even and odd number of carbon atoms, and butanol, isomers. These components have been added to conventional fuels, such as diesel fuel and Jet A-1 fuel at the concentration of 0–20% (V/V). All fuels under testing contained commercially available lubricity improvers (carboxylic acid). Test results were analysed using model αi described in [L. 6, 7]. As a result of the analysis, it has been found that the liquid phase, which is a lubricating film, should contain agglomerates or molecular clusters responsible for the transport of energy introduced into lubricating film by electrons emitted from metal surface. The mechanism enabling a description of the effect of base fuel without lubricity improvers on efficiency of such additives has been suggested.
    Przedmiotem artykułu jest mechanizm tworzenia warstwy smarującej przez paliwa zawierające syntetyczne węglowodory i alkohole. Rozwój paliw alternatywnych spowodował wzrost zainteresowania mechanizmem smarowania elementów układów zasilania silników. Badania smarności paliw prowadzono z użyciem aparatów HFRR i BOCLE. Badane paliwa do silników o ZS i paliwa do turbinowych silników lotniczych zawierały trzy serie syntetycznych komponentów: węglowodory parafinowe o parzystej liczbie atomów węgla, węglowodory parafinowe o nieparzystej liczbie atomów węgla oraz izomery butanolu. Powyższe syntetyczne komponenty były dodawane do mineralnych paliw: oleju napędowego i paliwa Jet A1 w ilości 0–20% (V/V). Wszystkie badane paliwa zawierały komercyjnie dostępne dodatki smarnościowe (kwas karboksylowy). Wyniki badań eksperymentalnych były analizowane z zastosowaniem modelu αi opisanego w publikacjach [L. 6, 7]. W rezultacie przeprowadzonej analizy stwierdzono, że faza ciekła – film smarny powinna zawierać aglomeraty lub klastry molekularne, które są odpowiedzialne za transport energii wprowadzanej do filmu smarnego przez elektrony emitowane z powierzchni metalu. Zaproponowano mechanizm, który może wyjaśnić wpływ paliwa bazowego (bez dodatków smarnościowych) na efektywność działania dodatków smarnościowych.
    Źródło:
    Tribologia; 2017, 273, 3; 91-100
    0208-7774
    Pojawia się w:
    Tribologia
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study of icosahedral clusters in close-packed simple liquids
    Autorzy:
    Kozub, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/1933986.pdf
    Data publikacji:
    2012
    Wydawca:
    Politechnika Gdańska
    Tematy:
    liquid metals
    icosahedral clusters
    structure
    molecular dynamics
    Opis:
    The local structure of liquid copper was determined using Steinhardt order parameters, with particular attention paid to icosahedral clusters. The positions of atoms were obtained from three sets of molecular dynamics simulations, with the forces obtained from: the Sutton-Chen (SC) potential, the Naval Research Laboratory total energy tight-binding (NRL-TB) method and the divide-and-conquer learn-on-the-fly (DCLOTF) method, respectively. A broad range of local geometries appeared, which is a typical result for close-packed liquids. Among them a number of icosahedral clusters were detected. The highest density of icosahedral clusters was obtained at the temperature of 1000K for the NRL-TB and DCLOTF simulations and 1200K for the SC simulations. I propose various means of analysing the icosahedral clusters formed in liquid copper. The average number of the clusters, their lifetime and correlations between them at various temperatures were studied as a function of the approach used to generate the trajectories. Finally, I studied the formation and decay of icosahedral clusters.
    Źródło:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2012, 16, 1-2; 75-96
    1428-6394
    Pojawia się w:
    TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Surface diffusion and cluster formation of gold on the silicon (111)
    Autorzy:
    Plechystyy, V.
    Shtablavyi, I.
    Rybacki, K.
    Winczewski, S.
    Mudry, S.
    Rybicki, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/952460.pdf
    Data publikacji:
    2020
    Wydawca:
    Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
    Tematy:
    molecular dynamics
    surface diffusion
    clusters
    atomic monolayer
    activation energy
    dynamika molekularna
    dyfuzja powierzchniowa
    klastry
    monowarstwa atomowa
    energia aktywacji
    Opis:
    Purpose: Investigation of the gold atoms behaviour on the surface of silicon by molecular dynamics simulation method. The studies were performed for the case of one, two and four atoms, as well as incomplete and complete filling of gold atoms on the silicon surface. Design/methodology/approach: Investigations were performed by the method of molecular dynamics simulation using the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS). MEAM potential of interatomic interaction was used for modelling. Molecular dynamic simulations were carried out in isothermal-isobaric ensemble (NpT) with a timestep 1.0 fs. Findings: As a result of studies, the preferred interaction between gold atoms and the formation of clusters at temperatures up to 800 K was revealed. Analysis of the temperature dependences of the number of large jumps of atoms made it possible to calculate the activation energy of a single jump. It was found that activation energy of single atomic displacement decreases with increasing number of gold atoms. Research limitations/implications: Only a limited number of sets of atoms were used in the study. It is possible that for another combination of atoms and a larger substrate surface, the formation of gold nanoislands on the silicon surface can be observed, which requires further research. Practical implications: The research results can be used to select the modes of gold sputtering to create gold nanoislands or nanopillars on the silicon surface. Originality/value: Computer modelling of the behaviour of gold atoms on the surface of silicon with the possibility of their self-organization and cluster formation was performed for the first time.
    Źródło:
    Journal of Achievements in Materials and Manufacturing Engineering; 2020, 101, 2; 49-59
    1734-8412
    Pojawia się w:
    Journal of Achievements in Materials and Manufacturing Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-4 z 4

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