The Effect of Anisotropic Focusing of Lamb Modes on a Carbon-Epoxy Plain Woven Fabric Composite Plate

10 páginas, 8 figuras, 1 tabla. 6th International Symposium on NDT in Aerospace, 12-14th November 2014, Madrid, SpainThe medium anisotropy give rise to interesting effects in the physics of wave propagation: the angular dependence of the group velocity, the skew angle between pha se and group velocities, and the elastic focusing leading to the concentration of wave energy in dete rminated directions. All these effects are mode dependent and must be taken into account to choose the ad equate propagating mode in NDE or SHM applications. In this article the dispersion curves of p hase and group velocities, and the patterns of wave focusing for the A0 and S0 modes are theoretically obt ained and verified experimentally. The angular dependence of the group velocity and the effect of the anisotropic elastic focusing is studied in a 1.97 mm-thickness multilayer carbon-epoxy plain woven fab ric composite. The time traces are obtained by scanning the plate with the aid of a retro-reflective film st uck to the surface using a laser Doppler vibrometer. A good agreement between the theory and the expe rimental results was obtained. The Maris factor corresponding to the A0 mode shows smoother angular v ariation than that of the S0 mode which depends much more on the direction.The authors wish to thank to the CAPES Foundation, Ministry of Education of Brazil and to the Ministerio de Economía y Competitividad del Gobierno de Esp aña (project FIS2013-46829-R) for partially support the work, and to the Alltec Materiais Compostos for preparing the laminate samples.Peer reviewe

Towards a non-invasive ultrasound method for the diagnosis of neonatal and infant meningitis

Lumbar Puncture (LP) is currently used to draw a sample of cerebrospinal fluid (CSF) and test for potentially lethal Bacterial Meningitis (BM) in infants (<1yr). Increased CSF cellularity is highly indicative of BM and triggers medication for the patient. In developed countries, 95% of LPs for BM in infants return negative. In developing countries, LPs are rarely available, with 50% of infants with BM dying from the disease. We propose using high-frequency ultrasounds (HFUS) to non-invasively determine CSF cell concentration through the fontanel. The aim of this study is to assess the capabilities of HFUS on a fontanel phantom involving mock CSF with varying leukocyte concentration and pig tissue.This work was supported in part by the Consejería de Educación, Juventud y Deporte de la Comunidad de Madrid (Spain) through the Madrid-MIT M+Visión ConsortiumPeer reviewe

Diseño e implementación de un sistema de imagen ultrasonica 3D

8 páginas. 4 figuras. 1 Tabla -- PACS: 43.35.Zc. -- Comunicación presentada en: 44º Congreso Español de Acústica - TecniAcustica 2013. Encuentro Ibérico de Acústica. EAA European Symposium on Environmental Acoustics and Noise Mapping, Valladolid, 1 - 4, Octubre, 2013[EN] In this paper the design process of an ultrasonic volumetric imaging system based on synthetic aperture focusing technique is presented. Based on minimum redundancy coarray of 2D aperture an d parallel processing techniques for beamforming an experimental system is developed to operate with a 2D array (3Mhz and 11x11 elements).[ES] Este trabajo describe el proceso de diseño e implementación de un sistema de imagen ultrasónica basado en la composición del coarray de mínima redundancia para aperturas 2D. Esta técnica de adquisición en combinación con la generación de imagen por apertura sintética, implementada por GPGPU, permite diseñar un sistema de imagen 3D con un número reducido de recursos. Se presentan resultados experimentales del sistema implementado sobre un equipo de imagen ultrasónica convencional para una apertura bidimensional de 3Mhz y 11x11 elementos.Este trabajo está financiado por el Gobierno de España a partir del Plan Nacional de I+D+i dentro del marco del proyecto DPI2010-19376.Peer reviewe

Determination of Sr-90 in milk samples from the study of statistical results

[Abstract] The determination of 90Sr in milk samples is the main objective of radiation monitoring laboratories because of its environmental importance. In this paper the concentration of activity of 39 milk samples was obtained through radiochemical separation based on selective retention of Sr in a cationic resin (Dowex 50WX8, 50-100 mesh) and subsequent determination by a low-level proportional gas counter. The results were checked by performing the measurement of the Sr concentration by using the flame atomic absorption spectroscopy technique, to finally obtain the mass of 90Sr. From the data obtained a statistical treatment was performed using linear regressions. A reliable estimate of the mass of 90Sr was obtained based on the gravimetric technique, and secondly, the counts per minute of the third measurement in the 90Sr and 90Y equilibrium, without having to perform the analysis. These estimates have been verified with 19 milk samples, obtaining overlapping results. The novelty of the manuscript is the possibility of determining the concentration of 90Sr in milk samples, without the need to perform the third measurement in the equilibrium

All-Path Bridging: Path Exploration Protocols for Data Center and Campus Networks

Today, link-state routing protocols that compute multiple shortest paths predominate in data center and campus networks, where routing is performed either in layer three or in layer two using link-state routing protocols. But current proposals based on link-state routing do not adapt well to real time traffic variations and become very complex when attempting to balance the traffic load. We propose All-Path bridging, an evolution of the classical transparent bridging that forwards frames over shortest paths using the complete network topology, which overcomes the limitations of the spanning tree protocol. All-Path is a new frame routing paradigm based on the simultaneous exploration of all paths of the real network by a broadcast probe frame, instead of computing routes on the network graph. This paper presents All- Path switches and their differences with standard switches and describes ARP-Path protocol in detail, its path recovery mechanisms and compatibility with IEEE 802.1 standard bridges. ARP-Path is the first protocol variant of the All-Path protocol family. ARP-Path reuses the standard ARP Request and Reply packets to explore reactively the network and find the fastest path between two hosts. We compare its performance in terms of latency and load distribution with link-state shortest-path routing bridges, showing that ARP-Path distributes the load more evenly and provides lower latencies. Implementations on different platforms prove the robustness of the protocol. The conclusion is that All-Path bridging offer a simple, resilient and scalable alternative to path computation protocols

All-Path Bridging: Path Exploration Protocols for Data Center and Campus Networks

Today, link-state routing protocols that compute multiple shortest paths predominate in data center and campus networks, where routing is performed either in layer three or in layer two using link-state routing protocols. But current proposals based on link-state routing do not adapt well to real time traffic variations and become very complex when attempting to balance the traffic load. We propose All-Path bridging, an evolution of the classical transparent bridging that forwards frames over shortest paths using the complete network topology, which overcomes the limitations of the spanning tree protocol. All-Path is a new frame routing paradigm based on the simultaneous exploration of all paths of the real network by a broadcast probe frame, instead of computing routes on the network graph. This paper presents All- Path switches and their differences with standard switches and describes ARP-Path protocol in detail, its path recovery mechanisms and compatibility with IEEE 802.1 standard bridges. ARP-Path is the first protocol variant of the All-Path protocol family. ARP-Path reuses the standard ARP Request and Reply packets to explore reactively the network and find the fastest path between two hosts. We compare its performance in terms of latency and load distribution with link-state shortest-path routing bridges, showing that ARP-Path distributes the load more evenly and provides lower latencies. Implementations on different platforms prove the robustness of the protocol. The conclusion is that All-Path bridging offer a simple, resilient and scalable alternative to path computation protocols

Evolución conceptual de los protocolos de puentes transparentes

Los puentes Ethernet transparentes son un elemento cada vez más importante en las redes de telecomunicaciones. Este artículo ofrece una visión panorámica de la evolución conceptual de los paradigmas de puentes durante las últimas décadas, desde los puentes transparentes con árbol de expansión hasta las propuestas actualmente en estandarización: por una parte Shortest Path Bridges, Provider Bridges y Provider Backbone Bridges en el IEEE 802.1; por otra parte Routing Bridges en el IETF. Estas propuestas buscan aumentar la escalabilidad y obtener una alta utilización de la infraestructura de red, así como la provisión de servicios basados en Ethernet a gran número de usuarios. Mediante un mapa genealógico y una tabla se resumen e ilustran los aspectos funcionales, la evolución de los puentes propuestos en cuanto a los mecanismos básicos empleados para el encaminamiento, reenvío y la prevención de bucles tales como protocolos de vector distancia y de estado de enlaces, árboles múltiples de expansión, jerarquización mediante encapsulado de tramas y prohibición de algunos giros en los nodos. La evolución reciente de las propuestas muestra claramente varias tendencias: el predominio de los protocolos de estado de enlaces como IS-IS para el encaminamiento y/o construcción de árboles múltiples, de los mecanismos de encapsulado, y la multiplicación de tipos de identificadores para etiquetar y procesar separada y homogéneamente miles de servicios y clientes

Enterramientos infantiles en el oppidum de El Molón (Camporrobles, Valencia)

Se analizan las inhumaciones perinatales identificadas en el oppidum de El Molón. Se trata de tres enterramientos, uno de ellos doble, probablemente gemelar, procedentes de espacios domésticos o áreas de producción, en algún caso con presencia de ajuar. Se fechan hacia el siglo II a.C.This article analyzes three perinatal burials from the oppidum of El Molón. One of them was double and probably a twin pregnancy. The burials seem to be originally from domestic spaces and production areas, in some cases they were found in the presence of funeral offerings. The burials are dated in around the second century BC

FICARAM-15 Cruise Report 20th March – 22nd May 2013 on board BIO Hespérides by the Group FICARAM

54 páginas, 19 figuras, 3 anexosThe FICARAM-15 is the fifteenth repetition of a section conducted in 1994. This section is part of the international program GOSHIP (http://www.go-ship.org/CruisePlans.html) to develop a globally coordinated network of sustained hydrographic sections as part of the global ocean/climate observing system. The objective of the FICARAM-15 cruise is to investigate the temporal evolution of the anthropogenic carbon and evaluate the CO2 absorption capacity of the South Atlantic region, the Equatorial zone, and the subtropical region of Azores-Gibraltar in the North Atlantic. This cruise is supported by the CATARINA project funded by the Ministry of Economy and Competitiveness (CTM2010-17141) and is part of the European Union FP7 project CARBOCHANGE (http://carbochange.b.uib.no/). The objective of FICARAM-15 cruise is framed in the CATARINA project conducted by the tasks I.2.1 (air-sea CO2 exchange) I.3 (ventilation of water masses), I.4.1 (zonal variability of N2O and CH4), I.4.2 (anthropogenic carbon storage), I.4.4 (saturation horizon of calcium carbonate along the section) and I.5.4 (evolution of the acidification rates). Another component of the FICARAM-15 cruise aims to examine the biological and biogeochemical mechanisms that hinder total dissolved organic carbon (DOC) remineralisation in marine systems, taking a multidisciplinary perspective and applying many different approaches. This is the global objective of the Spanish project DOREMI (CTM2012-34294) that joins this FICARAM-15 cruise.During the FICARAM cruise the physical oceanography group was responsible for collecting the following data sets: CTD and XBT data; vessel-mounted ADCP and lowered ADCP; continuous thermosalinograph. Physical oceanographers participated in the cruise financed through Project “Tipping Corners in the Meridional Overturning Circulation” (TIC-MOC), CTM2011-28867. The FICARAM-15 cruise was organized in two phases with a common sampling. LEG 1: From Punta Arenas (Chile) to Recife (Brazil): 62 stations. Chief Scientist: Aida F. Ríos, PI of CATARINA project LEG 2: From Recife (Brazil) to Cartagena (Spain): 46 stations Chief Scientist: Celia Marrasé, PI of DOREMI project This report contains the sampling of all the variables at each station along the FICARAM section, as well as the analysis of the biogeochemical variables and the preliminary results. The principal investigator of the DOREMI project produced another report with the common sampling section, showing the analysis and results of the experiments on dissolved organic matter carried out on board.This cruise is supported by the CATARINA project funded by the Ministry of Economy and Competitiveness (CTM2010-17141) and is part of the European Union FP7 project CARBOCHANGE (http://carbochange.b.uib.no/)Peer reviewe