1,734 research outputs found
Current-induced torques in textured Rashba ferromagnets
In systems with small spin-orbit coupling, current-induced torques on the
magnetization require inhomogeneous magnetization textures. For large
spin-orbit coupling, such torques exist even without gradients in the
magnetization direction. Here, we consider current-induced torques in
ferromagnetic metals with both Rashba spin-orbit coupling and inhomogeneous
magnetization. We first phenomenologically construct all torques that are
allowed by the symmetries of the system, to first order in
magnetization-direction gradients and electric field. Second, we use a
Boltzmann approach to calculate the spin torques that arise to second order in
the spin-orbit coupling. We apply our results to current-driven domain walls
and find that the domain-wall mobility is strongly affected by torques that
result from the interplay between spin-orbit coupling and inhomogeneity of the
magnetization texture.Comment: 9 pages, 3 figure
The catalytic oxidation of organic contaminants in a packed bed reactor
The catalytic oxidation of several hydrocarbons was studied over noble metal and metal oxide catalysts. A fast empirical method was developed to determine the minimum operating temperature required to guarantee complete conversion of the hydrocarbon.\ud
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The influence of the operating parameters such as the inlet concentration and residence time, as well as the chemical character of the component to be oxidized, have been investigated. The results can be described satisfactorily by a simple isothermal, plug flow reactor model and first-order reaction kinetics. In the case of simultaneous oxidation of different components a significant mixture effect was not observed. The presence of water in the feed did significantly inhibit the oxidation of alkanes.\ud
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Of the applied catalysts, Pt was the most effective for the combustion of the alkenes, whereas Pd showed a higher activity for the oxidation of alkanes
Формирование композиционных покрытий никель – бор – азот
The methods of X-ray analysis and electron microscopy have been used to study the structure
of nitrogen-ion implanted electrochemical Ni–B coatings with the boron concentration of 8,14
and 20 at %. The implantation is shown to increase coating microhardness from 5,1-5,9 GPa to
10,8-11,7 GPa.
The hardness increase of coatings is attributed to decrease of nickel boride particle size and
formation of γ-BN
Deficiencies in technical and vocational education and training lecturer involvement qualifications and its implications in the development of work related skills
Technical Vocational Education and Training (TVET) lecturers play an important role in providing a competent workforce that can contribute to the economy in countries worldwide. The critical role played by TVET lecturers requires of them to have appropriate academic qualifications, workplace qualifications and experience, and teaching qualifications. Research has shown that few lecturers have adequate and required academic, workplace and teaching qualifications. The purpose of this study was to determine the deficiencies in TVET lecturer qualifications and how these deficiencies are addressed by management at TVET colleges in South Africa. While a substantial number of lecturers had academic qualifications at the time of investigation, deficiencies were found in TVET lecturers’ workplace qualifications and experience, as well as in their teaching qualifications. Having identified the deficiencies in TVET lecturer's qualifications, recommendations have been made to serve as guidelines in addressing the lack of either academic, teaching or workplace qualifications and experience.
Maatregelen tegen pikkerij / kannibalisme
Snavelkappen is in de tekst van het Ingrepenbesluit omschreven als 'het verkorten van de onder- en/of bovensnavel'. Ook varianten als 'licht kappen' of 'snavel branden' vallen hier dus onder. Voor de pluimveehouderij betekent dat vooral dat de leghennen-
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