Nuclear pairing from microscopic forces: singlet channels and higher-partial waves

Background: An accurate description of nuclear pairing gaps is extremely important for understanding static and dynamic properties of the inner crusts of neutron stars and to explain their cooling process. Purpose: We plan to study the behavior of the pairing gaps $\Delta_F$ as a function of the Fermi momentum $k_F$ for neutron and nuclear matter in all relevant angular momentum channels where superfluidity is believed to naturally emerge. The calculations will employ realistic chiral nucleon-nucleon potentials with the inclusion of three-body forces and self-energy effects. Methods: The superfluid states of neutron and nuclear matter are studied by solving the BCS gap equation for chiral nuclear potentials using the method suggested by Khodel et al., where the original gap equation is replaced by a coupled set of equations for the dimensionless gap function $\chi(p)$ defined by $\Delta(p) = \Delta_F \chi(p)$ and a non-linear algebraic equation for the gap magnitude $\Delta_F = \Delta(p_F)$ at the Fermi surface. This method is numerically stable even for small pairing gaps, such as that encountered in the coupled $^3PF_2$ partial wave. Results: We have successfully applied Khodel's method to singlet ($S$) and coupled channel ($SD$ and $PF$) cases in neutron and nuclear matter. Our calculations agree with other ab-initio approaches, where available, and provide crucial inputs for future applications in superfluid systems.Comment: 18 pages and 9 figure

Behavioural clusters and predictors of performance during recovery from stroke

We examined the patterns and variability of recovery post-stroke in multiple behavioral domains. A large cohort of first time stroke patients with heterogeneous lesions was studied prospectively and longitudinally at 1-2 weeks, 3 months and one year post-injury with structural MRI to measure lesion anatomy and in-depth neuropsychological assessment. Impairment was described at all timepoints by a few clusters of correlated deficits. The time course and magnitude of recovery was similar across domains, with change scores largely proportional to the initial deficit and most recovery occurring within the first three months. Damage to specific white matter tracts produced poorer recovery over several domains: attention and superior longitudinal fasciculus II/III, language and posterior arcuate fasciculus, motor and corticospinal tract. Finally, after accounting for the severity of the initial deficit, language and visual memory recovery/outcome was worse with lower education, while the occurrence of multiple deficits negatively impacted attention recovery

Microscopic entropy of the charged BTZ black hole

The charged BTZ black hole is characterized by a power-law curvature singularity generated by the electric charge of the hole. The curvature singularity produces ln r terms in the asymptotic expansion of the gravitational field and divergent contributions to the boundary terms. We show that these boundary deformations can be generated by the action of the conformal group in two dimensions and that an appropriate renormalization procedure allows for the definition of finite boundary charges. In the semiclassical regime the central charge of the dual CFT turns out to be that calculated by Brown and Henneaux, whereas the charge associated with time translation is given by the renormalized black hole mass. We then show that the Cardy formula reproduces exactly the Bekenstein-Hawking entropy of the charged BTZ black hole.Comment: 9 pages, no figure

Model for heterogeneous catalysis on metal surfaces with application to hypersonic flows

A model for heterogeneous catalysis for Copper, Nickel, and Platinum has been devised. The model simulates the heterogeneous chemical kinetics of dissociated air flow impinging metal surfaces. Elementary phenomena such as, atomic and molecular adsorption, Eley-Rideal and Langmuir-Hinshelwood recombinations, and thermal desorptions have been accounted for. Comparisons with experimental results for Nitrogen and Oxygen recombination show good agreement. In the second part of this work, the finite rate catalysis model has been used to analyzed numerically the problems of the heterogeneous catalysis similarity between hypersonic ground testing and reentry flight. Therefore the flow around a blunt cone under these conditions has been calculated and results for heat fluxes and for a suggested similarity parameter have been compared and discussed

Diagnosis and analysis of two king-post trusses

An accurate geometric and mechanical evaluation of two king-post trusses, based in grading results with data gathered from NDT as well as from mechanical evaluation, followed by full-scale tests were performed. The trusses were reassembled in laboratory and submitted to a series of cyclic tests under symmetric and asymmetric loading. Strengthening techniques evaluated in precedents research steps were used in a second phase of the carrying tests.The first author gratefully acknowledges the Portuguese Foundation for Science and Technology, for his PhD grant SFRH/BD/18515/2004. The research described in this paper was conducted with financial support of the Portuguese Foundation for Science and Technology (POCI/ECM/56552/2004). This work has been carried out with a partial financial contribution of the Italian Earthquake Engineering Laboratory Network (RELUIS), within the research program carried out for the Italian Agency for Emergency Management

Structural analysis of two King-post timber trusses: non-destructive evaluation and load-carrying tests

The misunderstanding of the overall behaviour of traditional timber trusses can result in incorrect strengthening interventions or, frequently, on their replacement. Timber roof structures need a more concise knowledge of the real behaviour to determine internal loads and control the load transfer. For that, laboratory tests on scaled or full-scale specimens of members, connections and trusses are needed. In this paper, an accurate geometric and mechanical evaluation of the timber elements of two Kingpost timber trusses, based on grading results with data gathered from non-destructive tests (NDT), including mechanical evaluation of the modulus of elasticity in bending (MoE), followed by full-scale carrying tests were performed. The trusses were reassembled in laboratory and submitted to a series of symmetric and non-symmetric cyclic tests, according to the Limit States. Strengthening techniques evaluated in precedent research steps were used in a second phase of the load-carrying tests

Experimental analysis of laterally loaded nailed timber-to-concrete connections

This work intends to assess the accuracy of the methodology proposed in the Eurocode 5 for laterally loaded nailed timber-to-concrete connections. First, the adequacy of the methodology proposed by Eurocode 5 for the dowel-type fasteners is analyzed and discussed, using timber elements from Pinus pinaster Ait. Square and round smooth nails have been used, initially on push-out tests of single and double shear dowel-type connections. Later, a similar investigation is carried out on timber-concrete connections, using the same kind of fasteners (nails), in single shear, wood species and experimental procedure. The use and the influence of permanent formwork are also investigated. As a result, comparisons between the values obtained for the load-carrying capacity and the slip modulus using the analysis provided by the Eurocode 5, when existing, and the experimental results are presented

Asnas de madeira: a importância da rigidez das ligações

O presente trabalho pretende salientar a importância do conhecimento da rigidez das ligações das asnas de madeira tradicionais. Apresentam-se os resultados de uma campanha experimental sobre ligações entalhadas com dente simples. Através de ensaios monotónicos e cíclicos, analisaram-se ligações originais (não reforçadas) e estudou-se a utilização da braçadeira, do esquadro e de varões metálicos no seu reforço.Fundação para a Ciência e Tecnologia (FCT) - bolsa SFRH/BD/18515/2004, projecto de investigação POCI/ECM/56552/200

Experimental evaluation of different strengthening techniques of traditional timber connections

A series of monotonic and cyclic tests were performed on unstrengthened specimens, in order to characterize the original behavior of connections, representative of traditional timber trusses. Subsequently, connections strengthened with metal devices were tested under monotonic and cyclic loading. Test data of original connections has been gathered with the purpose of characterizing their behavior, in particular, the post-elastic response and the failure mode. Observing the behavior of strengthened connections under cyclic loading gave straight indications on the positive and negative characteristics of the different strengthening techniques analyzed.Fundação para a Ciência e a Tecnologia (FCT