Model based optimization criteria for the generation of deep compressive residual stress fields in high elastic limit metallic alloys by ns-laser shock processing

Laser Shock Processing (LSP) is based on the application of a high intensity pulsed Laser beam (IN1 GW/cm2; τb50 ns) on a metallic target forcing a sudden vaporization of its surface into a high temperature and density plasma that immediately develops inducing a shock wave propagating into the material. The main acknowledged advantages of LSP consist on its capability of inducing a relatively deep compression residual stresses field into metallic alloy pieces allowing an improved mechanical behavior, explicitly, the life improvement of the treated specimens against wear, crack growth and stress corrosion cracking. Due to these specific advantages, Laser Shock Processing is considered as a competitive alternative technology to classical treatments for improving fatigue, corrosion cracking and wear resistance of metallic materials, and is being developed as a practical process amenable to production technology. In this paper, a model based systematization of process optimization criteria and a practical assessment on the real possibilities of the technique is presented along with practical results at laboratory scale on the application of LSP to characteristic high elastic limit metallic alloys, showing the induced residual stresses fields and the corresponding results on mechanical properties improvement induced by the treatment. The homogeneity of the residual stress fields distribution following the laser treatment spatial density will be specially analyzed

Ganglión de la articulación tibioperonea proximal como causa de síndrome compartimental anterior de la pierna

Se expone un caso clínico de síndrome compartimental anterior de la pierna producido por un quiste sinovial dependiente de la articulación tibioperonea proximal. En la literatura son numerosos los casos de compresión neurológica por gangliones y a este nivel, del nervio ciático poplíteo externo o sus ramas por ganglión de la articulación tibioperonea superior, pero rara vez se ha mencionado la posibilidad de que tales lesiones pudieran generar un aumento crítico de la presión dentro del compartimento, posiblemente porque todo el cuadro clínico-patológico se atribuyera exclusivamente al atrapamiento neurológico. En tales cuadros mixtos, debe tenerse en cuenta el componente compartimental, cuya expresión clínica suele ser larvada y por tanto diagnosticado tardíamente, que impedirá la recuperación funcional completa en situaciones donde el compromiso neurológico fue diagnosticado y tratado a tiempo.A case of anterior tibial compartment syndrome causing by a ganglion cyst of the proximal tibio-fibular joint is reported. There are many reports of compression of the common peroneal nerve by ganglion cysts, but they have been rarely reported as a cause of compartment syndrome, perhaps because the entirely clinical case was imputed to neurological compression. In this mixed cases it might be taken into account the compartmental component, which early diagnosis is difficult and could have far-reaching implications for further clinical results

A striking morphotype of Aplidium proliferum (Milne Edwards, 1841) (Ascidiacea: Polyclinidae) from the Strait of Gibraltar

An unusual colonial ascidian with 1-2m in length, belonging to the genus Aplidium (Ascidiacea: Polyclinidae), has been sampled from the Strait of Gibraltar (Ras Leona, Morocco). The characteristics of the colony, zooids and larvae point us to A. proliferum. The species seems common in the NE Atlantic from the Shetland Islands to Mediterranean Sea, but it never has observed the size of colonies as found in this area, the Strait is the largest so far reported, which it is probably represents one of the longest ascidian worldwide.The first observations (2009) were made thanks to a grant from the Spanish Agency for International Cooperation and Development (AECID: A-016248/08)

Hallazgo de anémonas anillo (Anthozoa, Actiniaria) en la región de Azores

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Angle Dependence of the Transverse Thermal Conductivity in YBa2_2Cu3_3O7_7 single crystals: Doppler Effect vs. Andreev scattering

We have measured the transverse thermal conductivity $\kappa_{xy}$ of twinned and untwinned YBa$_2$Cu$_3$O$_7$ single crystals as a function of angle $\theta$ between the magnetic field applied parallel to the CuO$_2$ planes and the heat current direction, at different magnetic fields and temperatures. For both crystals we observed a clear twofold variation in the field-angle dependence of $\kappa_{xy}(\theta) = - \kappa^0_{xy}(T,B) \sin(2\theta)$. We have found that the oscillation amplitude $\kappa^0_{xy}$ depends on temperature and magnetic field. Our results show that $\kappa^0_{xy} = a B \ln(1/(bB))$ with the temperature- and sample-dependent parameters $a$ and $b$. We discuss our results in terms of Andreev scattering of quasiparticles by vortices and a recently proposed theory based on the Doppler shift in the quasiparticle spectrum.Comment: 5 pages, 4 figure