Search results for "Thermal"
showing 10 items of 3576 documents
Impact of Thermal Treatment on the Surface of Na0.5Bi0.5TiO3-Based Ceramics
2021
This research was funded by the European Regional Development Fund, grant number 1.1.1.2/VIAA/3/19/558. The Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme, grant number 739508.
Microstructure and mechanical effects of spark plasma sintering in alumina monolithic ceramics
2013
The specific effects of spark plasma sintering (SPS) on the creep behavior, microstructure and mechanical properties of alumina monolithic ceramic were investigated. SPS introduces strains that concentrate at grain boundaries and inhibit crack growth, resulting in an improvement in the flexural strength and fracture toughness. However, creep blocks grain boundary movements and decreases the reliability of the material. These strains can be removed by a post-sintering thermal treatment, which plays an important role in the distribution of dislocations.
Exploring the photothermo-catalytic performance of brookite tio2-ceo2 composites
2020
The thermocatalytic, photocatalytic and photothermo-catalytic oxidation of some volatile organic compounds (VOCs), 2-propanol, ethanol and toluene, was investigated over brookite TiO2-CeO2 composites. The multi-catalytic approach based on the synergistic effect between solar photocatalysis and thermocatalysis led to the considerable decrease in the conversion temperatures of the organic compounds. In particular, in the photothermo-catalytic runs, for the most active samples (TiO2-3 wt% CeO2 and TiO2-5 wt% CeO2), the temperature at which 90% of VOC conversion occurred was about 60 °
The influence of various synthesis methods on the catalytic activity of cerium oxide in one-pot synthesis of diethyl carbonate starting from CO2, eth…
2013
Different synthesis methods such as homogeneous precipitation at room temperature and supercritical water (T > 647 K and P > 22.1 MPa) were employed for cerium oxide preparation. Additionally, deposition of ceria on silica mesoporous material, SBA-15, was carried out. The obtained materials were characterized by means of X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, nitrogen physisorption, X-ray photoelectron spectroscopy and CO2 temperature programmed desorption. Considerable variations in physico-chemical properties of the resulting materials were observed. The catalytic activities of pristine cerium oxide and ceria loaded on SBA-15 support were…
Experimente zur Zeolithbildung durch hydrothermale Umwandlung
1974
The formation of zeolites by hydrothermal alteration has been investigated by taking trass from the Laach volcanic area as a sample. Zeolites to be found are chabazite, phillipsite and analcime, all of which originated from the same phonolitic glass. This paper aims at explaining the formation of zeolites by means of experimental alteration of the pumice with various solutions. NaOH and KOH solutions were used in the experiments, these limited the formation conditions of chabazite, phillipsite, analcime in alkaline environments. Moreover, experiments were carried out with H2O dist and with solutions that formed during the alteration of pumice by reacting with H2O. These experiments were con…
Effects of overabundant nitrate and warmer temperatures on charophytes: The roles of plasticity and local adaptation
2018
Global change effects, such as warming and increases in nitrogen loading, alter vulnerable Mediterranean aquatic systems, and charophytes can be one of the most affected groups. We addressed the possible interaction between these factors on two populations of the cosmopolitan charophytes Chara hispida and Chara vulgaris. Populations were taken from two different environments, a nitrate-poor mountain lake and a nitrate-rich Mediterranean coastal spring. The laboratory experiment had a 2 × 2 factorial design based on two nitrate levels (similar to and double the local conditions) and two temperatures. Increased temperatures favoured the growth of the four populations, but an increase in nitra…
Dinuclear Palladium(II) and -(III) Compounds with O,O-Chelating Ligands. Room-Temperature Direct 2-Phenylation of 1-Methylindole
2012
New dinuclear palladium(III) compounds of general formula Pd2[(C6H4)PPh2]2[O–O]2Cl2, O–O being chelating phenolates C6H4OC(O)R (R = CH3, 3a; R = C2H5, 3b; R = OPh, 3c) or acetylacetonates RC(O)CHC(O)R (R = CH3, 4a; R = CF3, 4b; R = C(CH3)3, 4c), have been obtained by oxidation with PhICl2 of the corresponding palladium(II) compounds. The stability of the new compounds has been studied by 31P NMR spectroscopy from 200 to 298 K. DFT calculations of the stability of the complexes have also been performed. In agreement with these calculations, only compound Pd2[(C6H4)PPh2]2[(CF3C(O)CHC(O)CF3]2Cl2, 6b, showed the highest thermal stability. 6b was characterized by X-ray diffraction methods, prese…
High-pressure study of substrate material ScAlMgO4
2011
We report on the structural properties of ScAlMgO4 studied under quasi-hydrostatic pressure using synchrotron high-pressure x-ray diffraction up to 40 GPa. We also report on single-crystal studies of ScAlMgO4 performed at 300 K and 100 K. We found that the low-pressure phase remains stable up to 24 GPa. At 28 GPa, we detected a reversible phase transformation. The high-pressure phase is assigned to a monoclinic distortion of the low-pressure phase. No additional phase transition is observed up to 40 GPa. In addition, the equation of state, compressibility tensor, and thermal expansion coefficients of ScAlMgO4 are determined. The bulk modulus of ScAlMgO4 is found to be 143(8) GPa, with a str…
Modeling of biomolecular machines in non-equilibrium steady states
2021
Numerical computations have become a pillar of all modern quantitative sciences. Any computation involves modeling--even if often this step is not made explicit--and any model has to neglect details while still being physically accurate. Equilibrium statistical mechanics guides both the development of models and numerical methods for dynamics obeying detailed balance. For systems driven away from thermal equilibrium such a universal theoretical framework is missing. For a restricted class of driven systems governed by Markov dynamics and local detailed balance, stochastic thermodynamics has evolved to fill this gap and to provide fundamental constraints and guiding principles. The next step…
Overview of the JET results
2015
Since the installation of an ITER-like wall, the JET programme has focused on the consolidation of ITER design choices and the preparation for ITER operation, with a specific emphasis given to the bulk tungsten melt experiment, which has been crucial for the final decision on the material choice for the day-one tungsten divertor in ITER. Integrated scenarios have been progressed with the re-establishment of long-pulse, high-confinement H-modes by optimizing the magnetic configuration and the use of ICRH to avoid tungsten impurity accumulation. Stationary discharges with detached divertor conditions and small edge localized modes have been demonstrated by nitrogen seeding. The differences in…