0000000000291616

AUTHOR

Kristaps Rubenis

0000-0002-9044-8479

showing 6 related works from this author

Studies of TiO<sub>2</sub> Ceramics Structure after Thermal Treatment at Different Conditions

2014

The present work describes results of investigation of structural characteristics of TiO2 ceramics, depending on temperature and thermal treatment conditions by using a variety of characterization techniques. TiO2 ceramics was prepared by extrusion method and developed as a material for electrodes for innovative water treatment technologies. It was shown that non-stoichiometric phase TiO1.95 was observed after thermal treatment of TiO2 ceramics under high vacuum conditions.

Materials scienceMechanical EngineeringUltra-high vacuumMetallurgyThermal treatmentCharacterization (materials science)Mechanics of Materialsvisual_artPhase (matter)Electrodevisual_art.visual_art_mediumGeneral Materials ScienceWater treatmentExtrusionCeramicKey Engineering Materials
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Triboelectrification of nanocomposites using identical polymer matrixes with different concentrations of nanoparticle fillers

2021

In this study, we investigate triboelectrification in polymer-based nanocomposites using identical polymer matrixes containing different concentrations of nanoparticles (NPs). The triboelectric surface charge density on polymer layers increased as the difference in nanoparticle filler concentration between the two triboelectric layers escalated, despite the fact that the polymer matrix was the same in both layers. This effect was observed in tests of various polymer types and filler NPs. Our mechanical experiments and finite element analysis simulations confirmed that polymeric triboelectrification is related to the surface viscoelastic deformation that occurs during mechanical contact and …

chemistry.chemical_classificationFiller (packaging)Materials scienceNanocompositeRenewable Energy Sustainability and the EnvironmentNanoparticleCharge density02 engineering and technologyGeneral ChemistryPolymer010402 general chemistry021001 nanoscience & nanotechnology01 natural sciencesViscoelasticity0104 chemical sciencesChemical engineeringchemistryCovalent bondGeneral Materials Science0210 nano-technologyTriboelectric effectJournal of Materials Chemistry A
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FeOOH and Mn8O10Cl3modified zeolites for As(V) removal in aqueous medium

2017

BACKGROUND Arsenic in drinking water poses serious potential health risks in more than 30 countries with total affected population of around 100 million people. The present study is devoted to the development of innovative sorbents based on zeolite materials for As(V) sorption by modifying raw materials with iron oxyhydroxide and manganese oxychloride. Natural clinoptilolite and synthetic zeolite A were modified in order to obtain improved sorption of As(V). Sorption properties of newly developed sorbents were studied. Zeolites containing natural clinoptilolite are chosen due to relatively low cost and their broad use in industrial production as well as characteristic large surface area. RE…

General Chemical EngineeringInorganic chemistryPopulationchemistry.chemical_element02 engineering and technologyManganese010501 environmental sciences01 natural sciencesInorganic Chemistrysymbols.namesakeAdsorptionAluminosilicateZeoliteeducationWaste Management and Disposal0105 earth and related environmental sciencesClinoptiloliteeducation.field_of_studyRenewable Energy Sustainability and the EnvironmentOrganic ChemistryLangmuir adsorption modelSorption021001 nanoscience & nanotechnologyPollutionFuel Technologychemistrysymbols0210 nano-technologyBiotechnologyJournal of Chemical Technology & Biotechnology
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Strong, Rapid and Reversible Photochromic Response of Nb doped TiO2 Nanocrystal Colloids in Hole Scavenging Media

2020

Understanding photochromicity is essential for developing new means of modulating the optical properties and optical response of materials. Here, we report on the synthesis and exciting new photochromic behavior of Nb5+ doped TiO2 nanoparticle colloids (NCs). We find that in hole scavenging media, Nb5+ doping significantly improves the photochromic response time of TiO2 nanoparticles. In the infrared regime, Nb-doped TiO2 NCs exhibit an order of magnitude faster photoresponse kinetics than the pristine TiO2. Enhanced photochromic response is observed in the visible light regime as well. The transmittance of Nb-doped TiO2 NCs drops to 10% in less than 2 minutes when irradiated by UV light in…

Materials scienceDopantInfraredDoping221 NanotechnologyPhotochemistry114 Physical sciencesNanoclustersPhotochromismNanocrystal216 Materials engineeringTransmittanceGeneral Materials ScienceVisible spectrum
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Investigation of TiO<sub>2</sub> Ceramic Surface Conductivity Using Conductive Atomic Force Microscopy

2012

Dense TiO2 (rutile) ceramic samples were prepared by sintering compacts of titanium dioxide anatase powder at 1500 °C for 5h. Sintered samples were polished and annealed in vacuum at 1000 °C for 1h. Structural properties of the samples were studied by X-ray diffraction, polarized light and scanning electron microscopy. The surface topography and local electrical conductivity of the samples were investigated by atomic force microscopy technique under atmospheric conditions. Enhanced electrical conductivity was observed at grain boundaries while the polished, vacuum annealed grains surface showed non-homogeneous conductivity.

AnataseMaterials scienceScanning electron microscopeMechanical EngineeringAnalytical chemistryConductive atomic force microscopyConductivitySurface conductivityMechanics of Materialsvisual_artvisual_art.visual_art_mediumGeneral Materials ScienceGrain boundaryCeramicPhotoconductive atomic force microscopyKey Engineering Materials
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Permanent photodoping of plasmonic gallium-ZnO nanocrystals

2020

This work was supported by the Latvian Council of Science in the framework of FLPP (Plasmonic oxide quantum dots for energy saving smart windows, lzp-2018/1-0187). Tanel Käämbre acknowledges financial support for the XPS instrumentation maintenance from the Estonian Centre of Excellence in Research project “Advanced materials and high- technology devices for sustainable energetics, sensorics and nanoelectronics” (TK141).

Materials scienceInfrared spectroscopychemistry.chemical_element02 engineering and technologyElectron010402 general chemistry01 natural sciences7. Clean energyoxygen vacanciesElectrical resistivity and conductivity:NATURAL SCIENCES:Physics [Research Subject Categories]General Materials ScienceGalliumPlasmonDopantbusiness.industryDopingtechnology industry and agriculture021001 nanoscience & nanotechnologyCrystallographic defect0104 chemical scienceschemistryOptoelectronicsnanoparticles0210 nano-technologybusiness
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