99 research outputs found
Multi-layered Ruthenium-modified Bond Coats for Thermal Barrier Coatings
Diffusional approaches for fabrication of multi-layered Ru-modified bond coats for thermal
barrier coatings have been developed via low activity chemical vapor deposition and high activity
pack aluminization. Both processes yield bond coats comprising two distinct B2 layers, based on
NiAl and RuAl, however, the position of these layers relative to the bond coat surface is reversed
when switching processes. The structural evolution of each coating at various stages of the
fabrication process has been and subsequent cyclic oxidation is presented, and the relevant
interdiffusion and phase equilibria issues in are discussed. Evaluation of the oxidation behavior of
these Ru-modified bond coat structures reveals that each B2 interlayer arrangement leads to the
formation of α-Al 2 O 3 TGO at 1100°C, but the durability of the TGO is somewhat different and in
need of further improvement in both cases
Gametófitos de Pleurosorus papaverifolius (Kunze) Fée (Aspleniaceae) y Cheilanthes glauca (Cav.) Mett. (Pteridaceae), dos helechos rupícolas sudamericanos
The averaged tensors of the relative energy-momentum and angular momentum in general relativity and some their applications
There exist at least a few different kind of averaging of the differences of
the energy-momentum and angular momentum in normal coordinates {\bf NC(P)}
which give tensorial quantities. The obtained averaged quantities are
equivalent mathematically because they differ only by constant scalar
dimensional factors. One of these averaging was used in our papers [1-8] giving
the {\it canonical superenergy and angular supermomentum tensors}.
In this paper we present another averaging of the differences of the
energy-momentum and angular momentum which gives tensorial quantities with
proper dimensions of the energy-momentum and angular momentum densities. But
these averaged relative energy-momentum and angular momentum tensors, closely
related to the canonical superenergy and angular supermomentum tensors, {\it
depend on some fundamental length }.
The averaged relative energy-momentum and angular momentum tensors of the
gravitational field obtained in the paper can be applied, like the canonical
superenergy and angular supermomentum tensors, to {\it coordinate independent}
analysis (local and in special cases also global) of this field.
We have applied the averaged relative energy-momentum tensors to analyze
vacuum gravitational energy and momentum and to analyze energy and momentum of
the Friedman (and also more general) universes. The obtained results are very
interesting, e.g., the averaged relative energy density is {\it positive
definite} for the all Friedman universes.Comment: 30 pages, minor changes referring to Kasner universe
Levantamento da flora vascular rupestre do Morro Sapucaia e Morro do Cabrito, Rio Grande do Sul
Monilófitas da Estação Ecológica do Panga, Uberlândia, Estado de Minas Gerais, Brasil: Dennstaedtiaceae, Dryopteridaceae, Gleicheniaceae, Hymenophyllaceae e Lindsaeaceae
Pteridófitas da vegetação nativa do Jardim Botânico Municipal de Bauru, Estado de São Paulo, Brasil
Pteridaceae (Polypodiopsida) do Campo Experimental da Embrapa Amazônia Oriental, município de Moju, estado do Pará, Brasil
Criptógamos do Parque Estadual das Fontes do Ipiranga, São Paulo, SP, Brasil. Pteridophyta: 3. Cyatheaceae
Licófitas e samambaias da estação ecológica do Panga, Uberlândia, MG, Brasil: equisetaceae, Lycopodiaceae e chave para as famílias
Registro de Floresta Ombrófila Mista nas regiões sudoeste e sul do Estado do Paraná, Brasil, durante o Pleistoceno/Holoceno
- …