19 research outputs found

    Impact of ionic liquids on the processing and photo-actuation behavior of SBR composites containing graphene nanoplatelets

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    The effects of butylpyridinium bromide-based ionic liquids (ILs) on the vulcanization kinetics, mechanical properties and photo-actuation ability of styrene-butadiene rubber (SBR) composites filled with graphene nanoplatelets (GnPs) were investigated. Two different ILs, 1-butylpyridinium bromide (BBP) and 4-methyl-1-butylpyridinium bromide (BMBP), were introduced into rubber compounds. The methodology of IL incorporation into the rubber compounds was studied as well. The ILs were added either directly as a single component or after immobilization onto the GnPs surface. High values of the modulus and tensile strength, which are important mechanical properties, were observed for the composites filled with immobilized BMBP. Freely dispersed BBP resulted in composites with the fastest scorch time, highest thermal and electrical conductivity, and best photo-actuation response of 0.230 mm. © 2020 The AuthorsMinistry of Education, Youth and Sports of the Czech republic - DKRVO [RP/CPS/2020/003]; National Science Centre, Poland through POLONEZ project [UMO-2016/23/P/ST5/02131]; European Unions's Horizon 2020 research and innovation program under Marie Sklodowska -Curie [665778]; Qatar University [QUCGCAM-19/20-2

    The effect of short polystyrene brushes grafted from graphene oxide on the behavior of miscible PMMA/SAN blends

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    A new concept of utilization of particle-polymer hybrids as multifunctional additives for polymer blends was introduced in this study. Graphene oxide particles with short densely grafted polystyrene brushes (GO-g-PS) were prepared by surface-initiated atom transfer radical polymerization (SI-ATRP). Melt rheology studies revealed that GO-g-PS suppressed the phase separation of miscible poly(methyl methacrylate)/poly(styrene-co-acrylonitrile) (PMMA/SAN) blends. The studies suggested specific interactions of GO-g-PS with the PMMA phase and this was confirmed based on calculations of activation energies of segmental relaxations by broadband dielectric spectroscopy (BDS). These unusual interactions of GO-g-PS with PMMA phase were assigned to the specific and precise architecture of the GO-g-PS particles as well as chemical nature of PS polymer brushes. The short chains of PMMA and PS provide miscibility originating from UCST behavior of PMMA/PS blend of short polymer chains. Additionally, BDS also revealed improved charge transport in PMMA/SAN blend in presence of GO-g-PS hybrid. © 2020 Elsevier LtdAction Austria - Slovakia, Co-operation in Science and Education program [56337]; National Science Centre, PolandNational Science Center, PolandNational Science Centre, Poland [UMO-2016/23/P/ST5/02131]; European Unions' Horizon 2020 research and innovation program under Marie Sklodowska-Curie grant [665778]; Research & Innovation Operational Programme - ERDF [313021T081]; project VEGAVedecka grantova agentura MSVVaS SR a SAV (VEGA) [2/0129/19]; Technology Agency of the CR [TN01000008]; Ministry of Education, Youth and Sports of the Czech Republic - DKRVO [RP/CPS/2020/003

    The usefulness of X-ray diffraction and thermal analysis to study dietary supplements containing iron

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    X-ray powder diffraction (XRPD) and thermal analysis (differential scanning calorimetry/ derivative of thermogravimetry (DSC/DTG)) are solid-state techniques that can be successfully used to identify and quantify various chemical compounds in polycrystalline mixtures, such as dietary supplements or drugs. In this work, 31 dietary supplements available on the Polish market that contain iron compounds, namely iron gluconate, fumarate, bisglycinate, citrate and pyrophosphate, were evaluated. The aim of the work was to identify iron compounds declared by the manufacturer as food supplements and to try to verify compliance with the manufacturer’s claims. Studies performed by X-ray and thermal analysis confirmed that crystalline iron compounds (iron (II) gluconate, iron (II) fumarate), declared by the manufacturers, were present in the investigated dietary supplements. Iron (II) bisglycinate proved to be semi-crystalline. However, depending on the composition of the formulation, it was possible to identify this compound in the tested supplements. For amorphous iron compounds (iron (III) citrate and iron (III) pyrophosphate), the diffraction pattern does not have characteristic diffraction lines. Food supplements containing crystalline iron compounds have a melting point close to the melting point of pure iron compounds. The presence of excipients was found to affect the shapes and positions of the endothermic peaks significantly. Widening of endothermic peaks and changes in their position were observed, as well as exothermic peaks indicating crystallization of amorphous compounds. Weight loss was determined for all dietary supplements tested. Analysis of the DTG curves showed that the thermal decomposition of most food supplements takes place in several steps. The results obtained by a combination of both simple, relatively fast and reliable XRPD and DSC/DTG methods are helpful in determining phase composition, pharmaceutical abnormalities or by detecting the presence of the correct polymorphic form

    Multicenter registry of Impella-assisted high-risk percutaneous coronary interventions and cardiogenic shock in Poland (IMPELLA-PL)

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    Background: Impella is a percutaneous mechanical circulatory support device for treatment of cardiogenic shock (CS) and high-risk percutaneous coronary interventions (HR-PCIs). IMPELLA-PL is a national retrospective registry of Impella-treated CS and HR-PCI patients in 20 Polish interventional cardiological centers, conducted from January 2014 until December 2021.Aims: We aimed to determine the efficacy and safety of Impella using real-world data from IMPELLA-PL and compare these with other registries.Methods: IMPELLA-PL data were analyzed to determine primary endpoints: in-hospital mortality and rates of mortality and major adverse cardiovascular and cerebrovascular events (MACCE) at 12 months post-discharge.Results: Of 308 patients, 18% had CS and 82% underwent HR-PCI. In-hospital mortality rates were 76.4% and 8.3% in the CS and HR-PCI groups, respectively. The 12-month mortality rates were 80.0% and 18.2%, and post-discharge MACCE rates were 9.1% and 22.5%, respectively. Any access site bleeding occurred in 30.9% of CS patients and 14.6% of HR-PCI patients, limb ischemia in 12.7% and 2.4%, and hemolysis in 10.9% and 1.6%, respectively.Conclusions: Impella is safe and effective during HR-PCIs, in accordance with previous registry analyses. The risk profile and mortality in CS patients were higher than in other registries, and the potential benefits of Impella in CS require investigation

    Przemysłowe skalowanie technologii niskotarciowych warstw hybrydowych na pierścieniach tłokowych

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    Technological trials of gas sulphonitriding processes for cast iron piston rings were carried out as an alternative to chromium electroplating for the production of low-friction layers. The effectiveness of different ways of packing heat treatment charges in minimising or eliminating deformation of the rings was compared, and the effectiveness of ring packing with restraining tooling was confirmed. The maximum duration of the gas sulphonitriding process was determined at 1 hour, both as a stand-alone process and as a component process in a multi-stage technology for the manufacture of low-friction hybrid layers, ensuring the maintenance of sufficient ring toughness for an opening during assembly.Przeprowadzono próby technologiczne procesów azotonasiarczania gazowego żeliwnych pierścieni tłokowych jako alternatywy wytwarzania warstw niskotarciowych dla chromowych powłok galwanicznych. Porównano skuteczność różnych sposobów upakowania wsadów do obróbki cieplno-chemicznej w minimalizacji bądź eliminowaniu odkształceń pierścieni. W tym zakresie potwierdzono skuteczność pakietowania pierścieni w specjalistycznym, krępującym oprzyrządowaniu technologicznym. Wyznaczono maksymalny czas trwania procesu azotonasiarczania gazowego – 1 godziny – zarówno jako procesu samodzielnego, jak i procesu składowego w wieloetapowej technologii wytwarzania niskotarciowych warstw hybrydowych, który gwarantuje zachowanie dostatecznej wiązkości pierścienia dla rozwarcia montażowego

    Low Frictional MoS2/WS2/FineLPN Hybrid Layers on Nodular Iron

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    The paper presents the new concept of low frictional hybrid composite coatings on nodular cast iron. The structure of it is multilayer and consists of MoS2 and/or WS2 nanoinclusions embedded in the iron nitrides’ zone and relatively deep hard diffusion zone. It offers a low friction coefficient as well as high wear resistance of coated parts. The details of technology as well as the mechanism of layer’s growth have been presented and discussed. The presented technology may be an interesting alternative for chromium-based galvanic coatings of piston rings made of nodular iron using Cr6+

    Warstwy kompozytowe MoS2/WS2/FineLPN – nowe podejście do powłok o niskim tarciu na pierścienie tłokowe

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    In the search for alternative processes of technologically difficult and environmentally dangerous galvanic chromium coatings on cast iron piston rings, composite coatings of low-friction nanoparticles MoS2, WS2and/or rGO embedded in a hard matrix of iron nitrides have been investigated. Laboratory tribological and operational tests on a real aircraft engine have been carried out to select the optimal technological parameters and microstructures of low frictional layers. A dry friction coefficient of 0.13 has been obtained for the best of the processes, i.e., four times lower than for raw reference samples (0.55). According to that technological option, the low-friction layers were produced for a set of rings for three cylinders of a Boxer aircraft engine and tested comparatively in an operational test with the rings in the other three cylinders. The experimental engine has passed the operational test obtaining the assumed power performance, fuel consumption and admission criteria of exhaust purity and oil purity.W poszukiwaniu alternatywnych procesów dla trudnych technologicznie i niebezpiecznych dla środowiska galwanicznych powłok chromowych na żeliwnych pierścieniach tłokowych badano powłoki kompozytowe z niskotarciowych nanocząstek MoS2, WS2 i/lub rGO osadzonych w twardej osnowie z azotków żelaza. Przeprowadzono laboratoryjne badania tribologiczne oraz próby eksploatacyjne na rzeczywistym silniku lotniczym w celu doboru optymalnych parametrów technologicznych i mikrostruktur warstw o niskim współczynniku tarcia. Dla najlepszego z procesów uzyskano współczynnik tarcia suchego na poziomie 0,13, czyli czterokrotnie niższy niż dla surowych próbek referencyjnych (0,55). Zgodnie z tą opcją technologiczną wytworzono warstwy o niskim współczynniku tarcia dla zespołu pierścieni do trzech cylindrów silnika lotniczego Boxer i przetestowano je porównawczo w próbie eksploatacyjnej z pierścieniami chromowanymi w pozostałych trzech cylindrach, uzyskując założone parametry mocy, zużycie paliwa oraz kryteria dopuszczenia czystości spalin i oleju

    Nitridiranje jekla HS6-5-2 v induktivno sklopljeni plazmi

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    This article presents research on the possibility of obtaining a hardened surface layer via nitriding in coupled plasma (ICP) for HS6-5-2 steel. The subject of the investigation was the influence of the process parameters on the properties of the obtained layers. The surface layers were characterized using an optical microscope, SEM (Scanning Electron Microscope), EDS (Energy Dispersive Spectroscopy), XRD (X-Ray Diffraction), and a microhardness tester. The generator power was changed gradually from 500 W to 2 kW and the tests were carried out for various process durations, from 15 to 45 minutes at a set pressure. The obtained results show the possibility of obtaining nitrided surface layers with a thickness of up to 0.1 mm and a significant increase in hardness in a very short time

    Impact of Ag Nanoparticles (AgNPs) and Multimicrobial Preparation (EM) on the Carcass, Mineral, and Fatty Acid Composition of Cornu aspersum aspersum Snails

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    The hygienic practices on farms should reduce pathogenic microorganisms while simultaneously not harming the animals themselves; they must also not degrade the products’ quality. We assessed the effect of covering feed tables with paint containing silver nanoparticles (AgNPs) and the periodic spraying of effective microorganisms (EM) on production indicators and basic chemical composition, mineral content and fatty acid profiles in the bodies of Cornu aspersum aspersum snails. The animals were divided into four groups: (1) control, (2) with feed tables covered with AgNPs paint, (3) with EM spray applied and (4) with both factors—AgNP paint and EM spray. The highest increase in Ag, Zn, Fe and Ca retention, and the remodelling of the fatty acid profile in the carcasses of snails was found to be in the group of animals in contact with the feed tables covered with AgNP paint. In the group of animals exposed to the action of EM, an increased retention of Fe, Cu, P, Mg and Zn was found
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