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    Wyświetlanie 1-9 z 9
    Tytuł:
    Collection of Industrial Oil Using Nanoparticles and Porous Powders of Silica
    Autorzy:
    Cho, Y.-S.
    Moon, J.-W.
    Tematy:
    silica nanopowders
    surface modification
    porous silica
    oil removal
    Pokaż więcej
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Powiązania:
    https://bibliotekanauki.pl/articles/351139.pdf  Link otwiera się w nowym oknie
    Opis:
    Industrial oil was collected using hydrophobic silica powders. Silica nanopowder was modified with octadecyltriethoxysilane (OTS) using spray pyrolysis reactor continuously. Besides nanoparticles, mesoporous silica powder synthesized using Pluronic P104 was adopted as another oil adsorbents. Spherical macroporous or meso-macroporous silica particles were prepared by selfassembly for the removal of oil. The effects of the amount of powder on the oil adsorption were studied and compared with the results of various silica powders. The meso-macroporous silica particles were found to be the most efficient, indicating that both specific surface area and porosity played crucial role.
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Application of quasi-equilibrated thermodesorption of hexane and cyclohexane for characterization of porosity of zeolites and ordered mesoporous silicas
    Autorzy:
    Dudek, Anna
    Mańko, Maria
    Makowski, Wacław
    Mlekodaj, Kinga
    Opis:
    Quasi equilibrated temperature programmed desorption and adsorption (QE-TPDA) of hexane and cyclohexane was applied for characterization of zeolites 5A, ZSM-5, 13X, Y, NaMOR and ordered mesoporous silicas MCM-41, MCM-41/TMB, SBA-15 and HMS. Similar QE-TPDA profiles of hexane and cyclohexane with a single desorption maximum were observed for the wide pore zeolites. No adsorption of cyclohexane for zeolite 5A and a single desorption maximum for ZSM-5 were found, while two-step desorption profiles of hexane were observed for these zeolites. Similar values of the adsorption enthalpy and entropy of hexane and cyclohexane were obtained by fitting the Langmuir model functions for the zeolites X and Y. For NaMOR and ZSM-5 larger differences in these parameters were found. A single desorption peak found at low temperatures in the QE-TPDA profiles of hexane and cyclohexane for the studied silicas was attributed to the multilayered adsorption on their mesopore surface. The adsorption isobars calculated from the thermodesorption profiles were fitted with the BET function. This way values of the specific surface area and the adsorption heat were calculated. Additionally values of the initial heat of adsorption were found by fitting the Henry’s law to the high-temperature sections of the linearized isobars. The largest deviations from the BET and Henry functions and the largest values of the adsorption heats found for SBA-15 indicated the greatest heterogeneity of the adsorption sites on its surface.
    Dostawca treści:
    Repozytorium Uniwersytetu Jagiellońskiego
    Artykuł
    Tytuł:
    Surface properties of the doped silica hydrophobic coatings deposited on plasma activated glass supports
    Autorzy:
    Chodkowski, Michał
    Terpiłowski, Konrad
    Goncharuk, Olena
    Tematy:
    hydrophobicity
    surface chemistry
    glass
    silica
    sol-gel method
    immersion
    plasma
    Pokaż więcej
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Powiązania:
    https://bibliotekanauki.pl/articles/110289.pdf  Link otwiera się w nowym oknie
    Opis:
    The paper discusses preparation and characteristics of silica hydrophobic layers deposited on the plasma-modified glass supports. The surfaces were investigated using wettability measurements, profilometry, photoacoustic and infrared spectroscopy, X-ray photoelectron spectroscopy as well as scanning electron microscopy. The wettability measurements showed that the obtained surfaces are hydrophobic – the water contact angle was in the range of 140-150 degrees. The photoacoustic and infrared spectroscopy as well as X-ray photoelectron spectroscopy disclosed the surface compositions, particularly that of the hydrophobic alkyl groups deposited on them. They were methyl groups introduced during hydrophobization by hexamethyldisilazane. In addition, it was found that the number of groups on the surface depends on the kind of plasma by which the supports were activated. The optical profilometer showed differences in the surface roughness which affects their hydrophobicity. Moreover, the surface free energies were determined using the contact angle hysteresis method. They disclosed differences in each surface, depending on the way of supports activation. The largest hydrophobicity was obtained on the layer deposited on the support activated by the argon plasma. However, support activation by the air plasma resulted in a decrease of hydrophobicity compared to that of the non-activated surface.
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Control of amine functionality distribution in polyvinylamine/SBA-15 hybrid catalysts for Knoevenagel condensation
    Autorzy:
    Drozdek, Marek
    Dudek, Barbara
    Wach, Anna
    Kuśtrowski, Piotr
    Szneler, Edward
    Opis:
    Poly(N-vinylformamide) was deposited on the surface of highly ordered hexagonal mesoporous silica SBA-15 by in situ polymerization. Acid-catalyzed hydrolysis followed by neutralization with NaOH (pH = 7.0–10.0) allowed obtaining the poly(vinylamine)/SBA-15 hybrid materials with various distributions of N-containing species, which were determined by XPS and DRIFT spectroscopy. The changes in the form of deposited polymer as well as its interaction with the silica support were discussed. The poly(vinylamine)/SBA-15 materials were tested as catalysts of Knoevenagel condensation of benzaldehyde with ethyl cyanoacetate, ethyl acetoacetate and diethyl malonate. It was found that the sample neutralized at pH = 9.0 showed the best catalytic performance, which was attributed to a high content of accessible NH2 groups.
    Dostawca treści:
    Repozytorium Uniwersytetu Jagiellońskiego
    Artykuł
    Tytuł:
    Electrokinetic properties of silica-titania mixed oxide particles dispersed in aqueous solution of C.I. Direct Yellow 142 dye – effects of surfactant and electrolyte presence
    Autorzy:
    Chibowski, Stanisław
    Wiśniewska, Małgorzata
    Wawrzkiewicz, Monika
    Hubicki, Zbigniew
    Goncharuk, Olena
    Tematy:
    silica-titania composite
    mixed oxides
    zeta potential
    solid surface charge density
    dye adsorption
    surfactant effect
    Pokaż więcej
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Powiązania:
    https://bibliotekanauki.pl/articles/1450752.pdf  Link otwiera się w nowym oknie
    Opis:
    The mixed $SiO_2$-$TiO_2$ oxide obtained by the pyrogenic method with the silica:titanium percentage ratio equal to 20:80 (ST80) was used in the experiments. The influence of azo dye C.I. Direct Yellow 142 (DY) adsorption at the mixed oxide-solution interface on the electrokinetic properties of solid particles was studied. To determine solid surface charge density and zeta potential of examined suspensions the potentiometric titration and Doppler laser electrophoresis techniques were applied. The changes in structure of electrical double layer formed on the mixed oxide surface in the dye presence were specified as a function of DY concentration, inorganic salt addition and surfactant introduction. The effects of surfactant type and its concentration were determined. Three surfactants of different ionic character (anionic SDS, cationic CTAB and nonionic Triton X-100) were used in measurements. The obtained electrokinetic characteristics of ST80 mixed oxide dispersed in aqueous solutions with various adsorbate compositions is essential for such suspensions stability.
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Investigations of protective coatings for castings of high-manganese cast steels
    Autorzy:
    Holtzer, M.
    Bobrowski, A.
    Drożyński, D.
    Mocek, J.
    Tematy:
    high manganese cast steel
    protective coating
    silica sand
    quality of surface
    staliwo wysokomanganowe
    powłoka ochronna
    piasek kwarcowy
    jakość powierzchni
    Pokaż więcej
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Powiązania:
    https://bibliotekanauki.pl/articles/382308.pdf  Link otwiera się w nowym oknie
    Opis:
    When cast steel castings are made in moulding sands on matrices of high-silica sand, which has a low fire resistance the problem of the so-called chemical penetration is distinctly visible. Whereas this effect appears to a small degree only when moulding sand matrices are of chromite, zircon or olivine sands. Therefore in case of making castings of high-manganese cast steel (e.g. Hadfield steel) sands not containing free silica should be applied (e.g. olivine sand) or in case of a high-silica matrix protective coatings for moulds and cores should be used. Two protective coatings, magnesite alcoholic (marked as coating 1 and coating 2) originated from different producers and intended for moulds for castings of the Hadfield steel, were selected for investigations. Examinations of the basic properties were performed for these coatings: viscosity, thermal analysis, sedimentation properties, wear resistance. In order to estimate the effectiveness of protective coatings the experimental castings were prepared. When applying coating 1, the surface quality of the casting was worse and traces of interaction between the casting material (cast steel) and the coating were seen. When protective coating 2 was used none interactions were seen and the surface quality was better.
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wpływ nanododatków ceramicznych na charakterystyki tribologiczne biodegradowalnych smarów plastycznych
    The influence of ceramic additives on tribological characteristics of biodegradable lubricating greases
    Autorzy:
    Kozdrach, R.
    Tematy:
    smar plastyczny
    właściwości przeciwzużyciowe
    właściwości przeciwzatarciowe
    powierzchnia tarcia
    krzemionka amorficzna
    krzemiany warstwowe
    dodatki smarne
    aparat czterokulowy
    lubricating grease
    antiwear properties
    antiscuffing properties
    friction surface
    amorphous silica
    silicates of stratified
    lubricating additives
    four-ball machine
    Pokaż więcej
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Powiązania:
    https://bibliotekanauki.pl/articles/190007.pdf  Link otwiera się w nowym oknie
    Opis:
    W publikacji przedstawiono wyniki badań wpływu dodatków ceramicznych na właściwości tribologiczne wybranych kompozycji smarowych. Do modyfikacji smarów plastycznych wytworzonych na bazie mineralnej, syntetycznej oraz roślinnej i zagęszczonych stearynianem litu zastosowano płomieniową krzemionkę amorficzną AerosilŽ oraz montmorylonit jako przedstawiciel krzemianów warstwowych. Za pomocą aparatu czterokulowego wykonano testy tribologiczne dla smarów bazowych, tzn. niezawierających dodatków modyfikujących, i porównano je z wynikami uzyskanymi dla smarów plastycznych zmodyfikowanych wyżej wymienionymi dodatkami. Do oceny tych właściwości wykorzystano wyniki badań granicznego obciążenia zużycia, obciążenia zespawania, obciążenia zacierającego, granicznego obciążenia zatarcia oraz granicznego nacisku zatarcia. Na podstawie wyników badań tribologicznych wybranych kompozycji smarowych stwierdzono, że zastosowane dodatki modyfikujące w postaci krzemionki amorficznej oraz montmorylonitu korzystnie wpływają na zmianę wartości poszczególnych parametrów określających poziom właściwości smarnych badanych kompozycji smarowych.
    The paper presents the results of research of ceramic additives on the change of the tribological properties of selected lubricating compositions. The study used of greases based on paraffin oil of pharmaceutical purity, rapeseed oil, and synthetic oil Priolube 3970. As a thickener of lubricating greases, lithium stearate was used. The lubricating compositions were produced using modified ceramic additives in the form of flame amorphous silica Aerosil and laminated silicates in the form of montmorillonite. These additives in amount of 8% m/m were introduced to the structure of each grease. In the early phase of the experiment, tribological tests of compositions containing from 1 to 10% additives were carried out to determine the optimum amount of lubricating compositions. The tribological tests were carried out using four-balls apparatus for lubricating greases not containing the modified additive, and the results were compared to the results obtained for lubricating greases modified with additives mentioned above. The tribological properties of the tested compositions were determined by measurement of the limiting load of wear (Goz/40), welding load (Fz), scuffing load (Ft), limiting load of scuffing (Foz), and the limiting pressure of seizure (Foz). The research affirmed, that the flame amorphous silica is a less effective modifier for reducing anti-scuffingly by stepwise increasing load of the friction, under conditions of linearly increasing load, seizure, and anti-wear under constant load of the friction than montmorillonite regardless of the base oil. However, the flame amorphous silica improves the resistance to scuffing of the surface layer and wear in relation the basic lubricating compositions.
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-9 z 9

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