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Wyszukujesz frazę "film stability" wg kryterium: Temat


Wyświetlanie 1-5 z 5
Tytuł:
Water film structure during rupture as revealed by MDS image analysis
Autorzy:
Truong, N. T.
Dang, L. X.
Lin, C.-L.
Wang, X.
Miller, J. D.
Powiązania:
https://bibliotekanauki.pl/articles/110251.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
image processing
molecular dynamics simulation
film stability
molecular porosity
Opis:
The structure of thin water films during the rupture process was investigated by a new approach, which combines molecular dynamics simulation (MDS) with image processing analysis. The analysis procedure was developed to convert MDS trajectories to readable 3D images. The water films were studied at different thicknesses by MDS to determine the critical thickness at which the film ruptures. The potential energy of each specific film thickness during the simulation time was analyzed, and the results showed that the potential energy of stable films remained unchanged while the potential energy kept decreasing for films which ruptured during the simulation time. By applying the new procedure, the molecular porosity, which is defined as the void fraction between the volume of molecular pores in the water film and the total volume of the water film, was calculated. The results of molecular porosity for different film thicknesses during the simulation time suggested a critical molecular porosity as 49%. In other words, stable films have a molecular porosity of less than 49%. If a water film has a molecular porosity greater than 49%, rupture occurs during the simulation.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 4; 1060-1069
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Molecular dynamics simulations study of nano bubble attachment at hydrophobic surfaces
Autorzy:
Jin, J.
Dang, L. X.
Miller, J. D.
Powiązania:
https://bibliotekanauki.pl/articles/109533.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
molecular dynamics simulations (MDS)
film stability
bubble attachment
interfacial water structure
Opis:
Bubble attachment phenomena are examined using Molecular Dynamics Simulations (MDS) for the first time. The simulation involves a nitrogen nano bubble containing 906 nitrogen molecules in a water phase with 74,000 water molecules at molybdenite surfaces. During a simulation period of 1 ns, film rupture and displacement occurs. The attached nanobubble at the hydrophobic molybdenite face surface results in a contact angle of about 90º. This spontaneous attachment is due to a “water exclusion zone” at the molybdenite face surface and can be explained by a van der Waals (vdW) attractive force, as discussed in the literature. In contrast, the film is stable at the hydrophilic quartz (001) surface and the bubble does not attach. Contact angles determined from MD simulations are reported, and these results agree well with experimental and MDS sessile drop results. In this way, film stability and bubble attachment are described with respect to interfacial water structure for surfaces of different polarity. Interfacial water molecules at the hydrophobic molybdenite face surface have relatively weak interactions with the surface when compared to the hydrophilic quartz (001) surface, as revealed by the presence of a 3 Å “water exclusion zone” at the molybdenite/water interface. The molybdenite armchair-edge and zigzag-edge surfaces show a comparably slow process for film rupture and displacement when compared to the molybdenite face surface, which is consistent with their relatively weak hydrophobic character.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 1; 89-101
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effects of humidity on the stability of LTCC pressure sensors
Autorzy:
Santo Zarnik, M.
Belavic, D.
Powiązania:
https://bibliotekanauki.pl/articles/221696.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
thick-film piezoresistive sensors
capacitive pressure sensors
offset stability
relative humidity
Opis:
LTCC-based pressure sensors are promising candidates for wet-wet applications in which the effect of the surrounding media on the sensor's characteristics is of key importance. The effect of humidity on the sensor's stability can be a problem, particularly in the case of capacitive sensors. A differential mode of operation can be a good solution, but manufacturing the appropriate sensing capacitors remains a major challenge. In the case of piezoresistive sensors the influence of humidity is less critical, but it still should be considered as an important parameter when designing sensors for low-pressure ranges. In this paper we discuss the stability of the sensors' offset characteristics, which was inspected closely using experimental and numerical analyses.
Źródło:
Metrology and Measurement Systems; 2012, 19, 1; 133-140
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ lotnych związków organicznych na stabilność rezystancyjnych czujników gazu
Influence of volatile organic compounds on the stability of resistive gas sensors
Autorzy:
Suchorska-Woźniak, P
Małozięć, G.
Teterycz, H.
Powiązania:
https://bibliotekanauki.pl/articles/156162.pdf
Data publikacji:
2014
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
czujniki grubowarstwowe
lotne związki organiczne
stabilność długookresowa
thick-film sensors
volatile organic compounds
long-term stability
Opis:
W artykule przedstawiono wyniki badań stabilności długookresowej czujników grubowarstwowych. Stabilność badano w atmosferze lotnych związków organicznych (LZO). Na podstawie uzyskanych wyników można stwierdzić, że stabilność czujników w bardzo dużym stopniu zależy do masy cząsteczkowej LZO. Przeprowadzono próby regeneracji czujników zatrutych LZO. Wyniki badań pokazały, że regeneracja jest możliwa.
In this paper there are presented the results of stability tests and the possibility of regeneration (after poisoning by volatile organic compounds – VOC) of thick-film gas sensors. The sensors were exposed to the atmosphere with a high concentration (1000 ppm) of VOC with a chain length of C6 to C12. The temperature stimulated conductance was measured. During the experiments the temperature was changed cyclically with rate 2 deg/sec. During the first increase in temperature the characteristic inflection in the dependence of conductance was observed due to the desorption of various components adsorbed on the surface of a gas sensitive material (Fig. 2). The results of experiments showed the high sensitivity of sensors in the atmosphere with VOC which was strongly dependent on the temperature (Fig. 3). However, the inactivation occurred rapidly in the presence of VOC with high molecular weight (Fig. 5a). The initial conductance gradually increased. Tests were also carried out to evaluate the possibility of temperature regeneration of sensors exposed to the atmosphere with a high concentration (1000 ppm) of VOC. For this reason after the exposition, the sensors were heated in the ambient atmosphere with cyclically changes of the temperature. The studies showed that after the first heating in the range from 150°C to 650°C the sensor parameters were close to the initial values (Fig. 5). Thus, sensors poisoned by VOC can be temperature regenerated in the atmospheric air.
Źródło:
Pomiary Automatyka Kontrola; 2014, R. 60, nr 3, 3; 152-155
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microalloying of Continuous Cast Aluminum Strip and Structural Modification Using Plastic Treatment to a 9 μm Foil (Patent no. 39762, P-377/76)
Autorzy:
Purenović, M. M.
Purenović, Jelena M.
Baralić, J. Č.
Powiązania:
https://bibliotekanauki.pl/articles/2203751.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
microalloying
modified continuous cast aluminum strip
nano oxide film
corrosion stability
plasticity
superplasticity
equiaxed structure
strain hardening
surface tension
crystallization zone
dendrites
crystal twinning
Opis:
Innovative procedure of microalloying continuous cast aluminum strip, thickness 10 mm, by Be, Zr and Mn using 3C Pechiney technology (no. 39762, P-377/76), and modifying the existing parameters for strip casting and crystallization was implemented under industrial conditions with two randomly selected batches 2×8 tones, without previous selection of standardized quality of aluminum, purity Al 99.5%, obtained by electrolysis. The application of microalloying and overall structural modification of the technology resulted in obtaining nanoscale, ultra-thin, compact oxide high-gloss film with uniform surface of continuous cast strip, instead of the usual thick and porous oxide film. The outcome of microalloying the obtained equiaxed fine-grained nano/micro structure was avoiding anisotropic and dendritic microstructure of the strip, and improving deformation and plastic properties of modified continuous cast strip subjected to the technology of plastic treatment by rolling until the desired foil thickness of 9 μm was obtained. The invention of microalloying and structural modification, including multiplying effect of several components, directly or indirectly, changed numerous structurally-sensitive properties. The obtained nano/micro structure of crystal grains with equiaxed structure resulted in the synergy of undesirable <111> and inevitable <100> and <110> textures. Numerous properties were significantly enhanced: elastic modulus was improved, and intensive presence of cracks in warm forming condition was prevented due to rapid increase of the number of grains to 10000 grains/cm2 in as-cast state.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 1; 345--357
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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