Material defect reconstruction by non-destructive testing with laser induced ultrasonics

Aligned with current research efforts and industrial applications on nondestructive testing, in this work, a hybrid system combining remotely induced laser ultrasonics with conventional transducer detection is studied for defects detection in metallic parts. The processing of the induced acoustic emission waves is proposed to be approached by means of a high-resolution volumetric signal processing procedure based on the synthetic aperture focusing technique for the benefit of the final 2D visualization of the defects. The advantages of the hybrid non-destructive testing approach and the performance of the processing technique are experimentally validated.Peer ReviewedPostprint (published version

The geopolitics of presence and absence at the ruins of Fort Henry

In recent years, scholars have examined the non- or more-than-human world from a variety of unique positions. This article draws on contemporary archaeology and assemblage theories in geography to put forward an understanding of everyday geopolitics that includes the presence of objects in the formation of state subjectivity. Our approach, however, reveals not only this disciplining force of objects but also the ontological absences that are also at the heart of post-structuralist theories of subjectivity. As such, the formation of object-oriented geopolitical subjectivity is also always haunted by these other affective forces that are part of being in the world. These theoretical considerations are substantiated in our study of the material culture of a military outpost in the highlands of northern Chile where the objects left behind by soldiers offer insight into the complexities of state subjectification and state–society relations in border regions

Behaviour of insulin Langmuir monolayers at the air–water interface under various conditions

Bovine insulin (INS) monolayers were spread from dilute HCl solution on aqueous subphases under various conditions of temperature (1525 °C), pH (110) and salt content (NaCl, Na3PO4, ZnCl2), and plots of surface pressure (π) against mean area per amino acid residue (A) were recorded during their compression at fast and slow barrier speeds. Although the characteristics and behaviour of the monolayers were significantly influenced by these variables, under none of the conditions studied did molecules of the film appear to migrate into the subphase. In most of conditions mentioned above, compression of these films seems likely to cause the partial submersion of the insulin molecules in the subphase, but these structural changes are relatively slow and essentially reversible. The formation of a relatively rigid, compact film structure, by molecular association, seems to be favoured by high subphase pH and by the presence of Zn2+ ions, while low pH and the presence of PO43 ions appear to favour the dissociation of oligomers, the extension of the monomers and the total submersion of their A chains in the subphase during compression. The presence of salts in the subphase also reduces the reversibility of the changes occurred under film compression.Ministerio de Ciencia y Tecnología | Ref. BQU2003-00949Xunta de Galici

Directional Ultrasound Source for Solid Materials Inspection: Diffraction Management in a Metallic Phononic Crystal

[EN] In this work, we numerically investigate the diffraction management of longitudinal elastic waves propagating in a two-dimensional metallic phononic crystal. We demonstrate that this structure acts as an "ultrasonic lens", providing self-collimation or focusing effect at a certain distance from the crystal output. We implement this directional propagation in the design of a coupling device capable to control the directivity or focusing of ultrasonic waves propagation inside a target object. These effects are robust over a broad frequency band and are preserved in the propagation through a coupling gel between the "ultrasonic lens" and the solid target. These results may find interesting industrial and medical applications, where the localization of the ultrasonic waves may be required at certain positions embedded in the object under study. An application example for non-destructive testing with improved results, after using the ultrasonic lens, is discussed as a proof of concept for the novelty and applicability of our numerical simulation study.H. Selim, J. Trull, C. Cojocaru, and R. Pico acknowledge partial support from the Spanish Ministry of Economy and Innovation (MINECO) and European Union FEDER through project PID2019-109175GB-C22. H. Selim, J. Trull, and C. Cojocaru acknowledge partial support from US Army Research, Development, and Engineering Command (RDECOM) through project W911NF-16-1-0563.Selim, H.; Picó Vila, R.; Trull, J.; Delgado Prieto, M.; Cojocaru, C. (2020). Directional Ultrasound Source for Solid Materials Inspection: Diffraction Management in a Metallic Phononic Crystal. Sensors. 20(21):1-18. https://doi.org/10.3390/s20216148S118202

The initial–final mass relationship of white dwarfs in common proper motion pairs and open clusters

We have studied white dwarfs in common proper motion pairs (CPMPs) to improve the semi-empirical initial–final mass relationship of white dwarfs. In this contribution, we re- port new results obtained from spectroscopic observations of both members of several CPMPs composed of a F, G or K type star and a DA white dwarf.Peer Reviewe

SWORD: Una utilidad para la integración de repositorios con aplicaciones de gestión docente

Comunicación presentada en el 9º Workshop de Rebiun sobre proyectos digitales, Investigación, innovación e información: tendencias en los sistemas digitales de gestión de la producción científica, celebrado en Salamanca los días 1 y 2 de octubre de 2009.[ES] La Universidad Politécnica de Cataluña ha desarrollado con la Facultad de Informática de Barcelona un sistema de integración de memorias y sus datos asociados de forma transparente durante el proceso administrativo por medio de unos conectores desarrollados conjuntamente por el servicio de Bibliotecas de la UPC y el laboratorio de cálculo de la FIB. Estos conectores se basan en la tecnología SWORD que por medio de XML codifican los datos introducidos y los pre-vuelcan en el depósito de trabajos académicos antes de la lectura de la memoria. Entendido esto, se expone el potencial de SWORD para la integración de los depósitos con el resto de sistemas de la Universidad y los resultados de esta cooperación exportable al resto de centros de la UPC.[EN] Technical University of Catalonia has developed with the Barcelona School of Informatics, an integration system for reports and associated data transparently during the administrative process through some connectors developed jointly by the Library Service of UPC and laboratory calculation of the FIB. These connectors are based on SWORD technology using XML to encode the data entered and pre-flushed to the deposit of scholarly works before reading from memory. Understood, discussed the potential for integrating SWORD deposits with other University systems and the results of this cooperation exportable to other centers of the UPC