Search results for "Mechanics of Materials"
showing 10 items of 2598 documents
Inhibitoren der Korrosion 25(1) - Über die Rolle der Kationen in Neutralsalzen bei der Korrosion von Eisenwerkstoffen in Gegenwart von Sauerstoff
1979
Die Geschwindigkeit des Sauerstoffverbrauchs bei der Korrosion von jeweils 500 mg DAB6-Eisenpulver wird in Abhangigkeit von der Art des Kations in Neutralsalzen (Chloriden) unter Standardbedingungen bestimmt. In Gegenwart von Alkali-, Quartaren Ammonium, Quartaren Phosphonium-und Erdalkalichloriden ist die Geschwindigkeit des Sauerstoffverbrauches vergleichbar gros. Mit Zink-, Cadmium-, Nickel-und Kobaltchloriden wird aber im Bereich von pH5 bis pH7 eine uberraschend grose Verzogerung der Sauerstoffaufnahme beobachtet. Es handelt sich mit hoher Wahrscheinlichkeit um eine Blockade der kathodischen Bezirke in der Eisengrenzflache durch Abscheidung der schwerloslichen basischen Hydroxyde von Z…
Fe and Zn co-substituted beta-tricalcium phosphate (β-TCP): Synthesis, structural, magnetic, mechanical and biological properties
2020
This work was supported by the European Social Fund under the No. 09.3.3- LMT-K-712 “Development of Competences of Scientists, other Researchers and Students through Practical Research Activities” measure. AK would like to express sincere gratitude for Fellowship administrated by The Japan Society for the Promotion of Science (JSPS). Fellow’s ID No.: L12546. Authors are grateful to R. Vargalis (Vilnius University) for taking SEM images. © 2020. This work is licensed under a CC BY-NC-ND license.
A Study on Acidification and Intercalation of Illite Clay Minerals and their Potential Use as a Filler in SPEEK Composite Membranes
2018
The acidification and intercalation of illite containing clays were studied for potential use as fillers for sulphonated poly (ether ether ketone) (SPEEK) composite membrane preparation and future proton exchange membrane fuel cells application. The acidification and dimethyl sulfoxide (DMSO) intercalation of illite clays have been studied by powder X-ray diffractometry, X-ray fluorescence spectrometry, and thermogravimetric analysis. SPEEK composite membranes were made with 1, 3 and 5% purified, acidified, DMSO intercalated clay fillers. SPEEK/clay composite membranes were characterized by proton conductivity, water uptake, and mechanical strength.
Improvement of catalytic activity over Cu--Fe modified Al-rich Beta catalyst for the selective catalytic reduction of NOx with NH3
2016
Copper and iron bimetal modified Al-rich Beta zeolites from template-free synthesis were prepared for selective catalytic reduction (SCR) of NOx with NH3 in exhaust gas streams. Comparing to the Cu-based and Fe-based mono-component Beta catalysts, Cu(3.0)-Fe(1.3)-Beta bi-component catalyst shows better low-temperature activity and wider reaction-temperature window. Over 80% of NO conversion can be achieved at the temperature region of 125–500 °C. Due to the synergistic effect of copper and iron evidenced by XRD, UV–Vis–NIR, EPR and XPS measurements, the dispersion state of active components as well as the ratio of Cu2+/Cu+ and Fe3+/Fe2+ were improved over Cu(3.0)-Fe(1.3)-Beta. Isolated Cu2+…
Surface enhanced Raman scattering of silver sensitized cobalt nanoparticles in metal–dielectric nanocomposites
2008
We report the preparation of a new type of nanocomposite containing cobalt and silver nanoparticles organized in parallel layers with a well controlled separation. This arrangement allows the observation of an enhanced low-frequency Raman signal at the vibration frequency of cobalt nanoparticles excited through the surface plasmons of silver nanoparticles. Numerical simulations of the electric field confirm the emergence of hot spots when the separation between silver and cobalt nanoparticles is small enough. © IOP Publishing Ltd.
Natural Radioactivity in Clay Ceramics and their Raw Materials in Latvia
2018
Natural radionuclides K-40, and Th-232, U-238 (Ra-226) decay chain products contained in building materials are the main source of radiation dose received by population and the only source of indoor radiation exposure. Present work contains results of the study of natural radionuclide activity level in clay, clay ceramics and silica bricks used in Latvia. Obtained data show that radionuclide content in different clay products can differ up to five times. However, determined activity index values for all tested materials, except fireproof bricks, were below radionuclide concentration level permitted by EU and Latvian national regulations. Comparison with analogous data from other North Europ…
Novel organo-modifier for thermally-stable polymer-layered silicate nanocomposites
2015
A new novel approach for the stabilisation of polymer-clay nanocomposites has been investigated based on reacting chemically an antioxidant function, a hindered phenol moiety, with an organic modifier based on a quaternary ammonium salt. The chemically linked antioxidant-containing organic modifier (AO-OM) was then introduced into natural montmorillonite (MMt) through a cation-exchange reaction resulting in antioxidant-containing organo-modified clay (AO-OM-MMt). The new antioxidant-containing modified clay, along with other organo-modified clays having a similar organo-modifier but without the reacted antioxidant, were characterised by spectroscopic, thermogravimetric and x-ray diffraction…
Simulation of Fatigue Delamination Growth in Composites with Different Mode Mixtures
2007
A numerical model, obtained by implementing a cyclic damage model in the framework of an interface element, is here proposed to reproduce the crack growth in laminated composites subjected to cyclically repeated loads. This model, which differs from the few studies in the literature on the topic, applies not only to single fracture modes but also to mixed modes, and to constant or variable crack growth rates. The applied load (in terms of force or displacement) is assumed to oscillate between a minimum and a maximum constant value. The Paris curve can be reproduced with accuracy once some parameters in the numerical model are tuned with experiments. These parameters are preliminarily found…
Deterministic Modification of CVD Grown Monolayer MoS2 with Optical Pulses
2021
| openaire: EC/H2020/820423/EU//S2QUIP | openaire: EC/H2020/834742/EU//ATOP Transition metal dichalcogenide monolayers have demonstrated a number of exquisite optical and electrical properties. Here, the authors report the optical modification of topographical and optical properties of monolayer MoS2 with femtosecond pulses under an inert atmosphere. A formation of three-dimensional structures on monolayer MoS2 with tunable height up to ≈20 nm is demonstrated. In contrast to unmodified monolayer MoS2, these optically modified structures show significantly different optical properties, such as lower photoluminescence intensity and longer fluorescence lifetime. The results suggest a novel way…
Modelling landslides in unsaturated slopes subjected to rainfall infiltration using material point method
2016
This paper presents a dynamic fully coupled formulation for saturated and unsaturated soils that undergo large deformations based on material point method. Governing equations are applied to porous material while considering it as a continuum in which the pores of the solid skeleton are filled with water and air. The accuracy of the developed method is tested with available experimental and numerical results. The developed method has been applied to investigate the failure and post-failure behaviour of rapid landslides in unsaturated slopes subjected to rainfall infiltration using two different bedrock geometries that lie below the top soil. The models show different failure and post-failur…