Aerothermal modeling, phase 1. Volume 2: Experimental data

The experimental test effort is discussed. The test data are presented. The compilation is divided into sets representing each of the 18 experimental configurations tested. A detailed description of each configuration, and plots of the temperature difference ratio parameter or pattern factor parameter calculated from the test data are also provided

Aerothermal modeling. Executive summary

One of the significant ways in which the performance level of aircraft turbine engines has been improved is by the use of advanced materials and cooling concepts that allow a significant increase in turbine inlet temperature level, with attendant thermodynamic cycle benefits. Further cycle improvements have been achieved with higher pressure ratio compressors. The higher turbine inlet temperatures and compressor pressure ratios with corresponding higher temperature cooling air has created a very hostile environment for the hot section components. To provide the technology needed to reduce the hot section maintenance costs, NASA has initiated the Hot Section Technology (HOST) program. One key element of this overall program is the Aerothermal Modeling Program. The overall objective of his program is to evolve and validate improved analysis methods for use in the design of aircraft turbine engine combustors. The use of such combustor analysis capabilities can be expected to provide significant improvement in the life and durability characteristics of both combustor and turbine components

Breakdown of the Fermi-liquid regime in the 2D Hubbard model from a two-loop field-theoretical renormalization group approach

We analyze the particle-hole symmetric two-dimensional Hubbard model on a square lattice starting from weak-to-moderate couplings by means of the field-theoretical renormalization group (RG) approach up to two-loop order. This method is essential in order to evaluate the effect of the momentum-resolved anomalous dimension $\eta(\textbf{p})$ which arises in the normal phase of this model on the corresponding low-energy single-particle excitations. As a result, we find important indications pointing to the existence of a non-Fermi liquid (NFL) regime at temperature $T\to 0$ displaying a truncated Fermi surface (FS) for a doping range exactly in between the well-known antiferromagnetic insulating and the $d_{x^2-y^2}$-wave singlet superconducting phases. This NFL evolves as a function of doping into a correlated metal with a large FS before the $d_{x^2-y^2}$-wave pairing susceptibility finally produces the dominant instability in the low-energy limit.Comment: 9 pages, 9 figures; published in Phys. Rev.

Bounds on topological Abelian string-vortex and string-cigar from information-entropic measure

In this work we obtain bounds on the topological Abelian string-vortex and on the string-cigar, by using a new measure of configurational complexity, known as configurational entropy. In this way, the information-theoretical measure of six-dimensional braneworlds scenarios are capable to probe situations where the parameters responsible for the brane thickness are arbitrary. The so-called configurational entropy (CE) selects the best value of the parameter in the model. This is accomplished by minimizing the CE, namely, by selecting the most appropriate parameters in the model that correspond to the most organized system, based upon the Shannon information theory. This information-theoretical measure of complexity provides a complementary perspective to situations where strictly energy-based arguments are inconclusive. We show that the higher the energy the higher the CE, what shows an important correlation between the energy of the a localized field configuration and its associated entropic measure.Comment: 6 pages, 7 figures, final version to appear in Phys. Lett.

Análise do déficit de polinização da castanheira-do-brasil (Bertholletia excelsa BONPL., LECYTHIDACEAE) através de crescimento de tubos polínicos em pistilos submetidos a testes de polinização controlada.

A castanheira-do-brasil (Bertholletia excelsa Bonpl., Lecythidaceae) é uma planta alógama com síndrome de polinização melitófila. A deficiência quantitativa ou qualitativa na polinização reduz o sucesso reprodutivo das plantas. Esse trabalho avaliou o déficit de polinização de B. excelsa em uma área cultivada localizada em Tomé-Açu/PA, onde predomina o Sistema Agroflorestal. Foram realizados testes de polinização controlada (xenogamia, autopolinização induzida, autopolinização espontânea e geitonogamia), e avaliada a polinização natural em flores não manipuladas. Foram feitas análises do sistema de autoincompatibilidade nos pistilos usados nos testes e na polinização livre, através da observação da germinação do pólen e crescimento de tubos polínicos sob fluorescência. Registrou-se déficit de polinização em duas (P1 e P4), uma vez que a taxa de polinização natural ficou abaixo dos resultados da polinização cruzada manual (xenogamia). O déficit pode ser justificado pela menor diversidade de polinizadores, em comparação com outras áreas de cultivo estudadas, que pode ter influenciado na redução da taxa de deposição de pólen e determinou a limitação do fluxo gênico