Synthesis of Y1BaCu3O(x) superconducting powders by intermediate phase reactions

A procedure for synthesizing Y1Ba2Cu3O(x) by solid state reactions was developed. The method is based on the use of barium compounds, previously synthesized, as intermediate phases for the process. The reaction kinetics of this procedure were established between 860 C and 920 C. The crystal structure and the presence of second phases were studied by means of XRD. The sintering behavior and ceramic parameters were also determined. The orthorhombic type-I structure was obtained on the synthesized bodies after a cooling cycle in an air atmosphere. Superconducting transition took place at 91 K. Sintering densities higher than 95 percent D sub th were attained at temperatures below 940 C

Physicochemical, functional and structural characterization of fibre from defatted Rosa rubiginosa and Gevuina avellana seeds

The composition, functional properties and structural features of the fiber from Rosa rubiginosa defatted seeds and from Gevuina avellana defatted and partially deproteinized seeds were evaluated. The effect of phosphate salts and temperature during the extraction of fibres and the influence of two drying technologies on the distribution of soluble and insoluble dietary fibre were assessed. The extraction of protein and monosaccharides was favoured by increasing temperature in the range studied. Water and oil absorption capacities higher than 10 g g¯¹ were observed for soluble and insoluble fibres from Gevuina avellana and for the soluble ones from Rosa rubiginosa. The insoluble fibre product from Rosa and Gevuina contained 650-810 g kgˉ¹ and 390-440 g kg¯¹ neutral detergent fibre respectively. The protein content in the insoluble fibre varied in the range 100-150 g kg¯¹ and 120-260 g kg¯¹ and in the soluble fibre between 200-550 g kg¯¹ and 180-370 g kg¯¹ for Rosa and Gevuina respectively.European Commission - INCO-DC. Xunta Galicia - University of Vigo - ERBIC 18 CT 970206, MEC (ALI98-1641-CE)

Photoplethysmographic sensors for perfusion measurements in spinal cord tissue

Sensors for recording photoplethysmographic signals from the nervous tissue of the spinal cord are described. The purpose of these sensors is to establish whether perfusion is compromised in various states of injury which occur in certain animal models of spinal cord injury, for example compression injury. Various measures of perfusion are applicable such as the amplitude of the photoplethysmograph signal and the oxygen saturation, measured using a dual wavelength configuration. Signals are usually compared to baseline measurements made in uninjured subjects. This paper describes two types of probe, one based on optical fibres, and one in which optotes are placed in direct contact with the tissue surface. Results from a study based on a compression model utilising a fibreoptic sensor are presented

CoSb3-based skutterudite nanocomposites prepared by cold sintering process with enhanced thermoelectric properties

We show here for the first time the use of a cold sintering process (CSP) to sinter CoSb3-based thermoelectric materials. CSP at 150 {\deg}C for 90 min under a uniaxial pressure of 750 MPa yields pieces with a relative density of 86 %, which is increased to around 92 % after a post-annealing at temperatures > 500 {\deg}C in Ar atmosphere. The reported CSP produces Te doped-CoSb3 nanocomposites with similar morphological and structural characteristics to the starting nanopowders obtained by ball milling in air atmosphere. The post-thermal treatment induces grain coalescence and grain growth, crystallite size growth as well as compositional changes in the nanocomposite, decreasing the amount of the main phase, CoSb3, and increasing the weight of secondary phase, CoSb2, up to a 30 wt% at 600 {\deg}C. Remarkably, the average valence for the Co, Sb and Te absorbing atoms is neither transformed by the sintering process nor by the subsequent heat treatment. The functional response of the sintered thermoelectric nanocomposites exhibits a maximum figure of merit of 0.12(3) at room temperature for the nanocomposites sintered by CSP with a subsequent post-annealing at 500 {\deg}C. This is mainly due to its low thermal conductivity in comparison with similar powders sintered by other approaches, and it is explained by the morphological and structural properties. These findings represent an attractive alternative for obtaining efficient thermoelectric skutterudites by a scalable and cost-effective route

Optical measurement of blood flow changes in spinal cord injury

Little is known about cell death in spinal cord tissue following compression injury, despite compression being a key component of spinal injuries. Currently models are used to mimic compression injury in animals and the effects of the compression evaluated by observing the extent and duration of recovery of normal motor function in the days and weeks following the injury. A fibreoptic photoplethysmography system was used to investigate whether pulsation of the small arteries in the spinal cord occurred before, during and after compressive loads were applied to the tissue. It was found that the signal amplitudes were reduced and this reduction persisted for at least five minutes after the compression ceased. It is hoped that results from this preliminary study may improve knowledge of the mechanism of spinal cord injury

TDR-LAB 2.0: Improved TDR software for soil water content and electrical conductivity measurements

Trabajo presentado en las XI Jornadas de Investigación en la Zona No Saturada del Suelo celebradas en Lugo del 6 al 8 de noviembre de 2013.[ES]: La técnica de Reflectometría de Dominio Temporal (TDR) permite estimar la humedad (θ) y la conductividad eléctrica aparente del suelo (σa). Esta comunicación presenta una nueva versión del programa TDR-Lab para la medida de θ y σa. El TDR-Lab 2.0 es compatible con tres ecómetros TDR diferentes y puede conectarse a multiplexores SDMX50 (Campbell Sci). Puede estimar θ y σa por métodos gráficos y numéricos y incluye nuevas aplicaciones para la medida de niveles de agua, potencial mátrico o conductividad eléctrica de la solución del suelo. Está disponible en una versión ligera que trabaja con ficheros XML y una versión completa que centraliza los datos en una base SQL. Una robusta interface de importación-exportación de datos permite comunicar ambas versiones.[EN]: Time Domain Reflectometry (TDR) is a widely used technique that allows real time estimation of soil volumetric water content (θ), and bulk electrical conductivity (σa). This work presents an enhanced release of TDR-Lab, software which controls instrumentation for measurements of θ and σa. TDR-Lab 2.0 supports three different TDR equipments and can be connected to a multiplexing system (SDMX50, Campbell Sci). Graphical or numerical methods can be used for the estimation of θ and σa. Additional features to carry out water-surface-level measurements such as matric potential and soil solution electrical conductivity are also available. A little and a full release, for field and laboratory applications have been developed. The light version works with XML-files instead of the SQL database engine of the extended TDRLab. A robust import/export graphical user interface facilitates transferring projects between the centralized SQL database and XML files.This research was supported by the Ministerio de Educación y Ciencia of Spain (grant AGL2010-22050-C03-02) and DGA- Obra social La Caixa (Grants: 2012/ GA LC 074).Peer reviewe

Cytogenetic characterization of two species of Frieseomelitta Ihering, 1912 (Hymenoptera, Apidae, Meliponini)

The cytogenetic analysis of Frieseomelitta dispar and F. francoi revealed the chromosome numbers 2n = 30 and n = 15 and a karyotypic formula 2K = 4M+2Mt+4A+20AM. The number of chromosomes observed was consistent with those reported for other Frieseomelitta species. The occurrence of the Mt chromosome and other features of the karyotype formulae suggest a close relationship between F. dispar, F. francoi and F. varia. Nevertheless, it was possible to differentiate the karyotypes of the species by DAPI/CMA3 staining, which revealed GC-rich regions on two chromosome pairs of F. dispar: one acrocentric and one pseudoacrocentric. In F. francoi, the same kinds of regions were observed on a pair of metacentrics and on a pair of acrocentrics. Our analysis also confirmed the chromosome number conservation in Frieseomelitta and suggests that infrequent pericentric inversion could constitute a synapomorphy for the group including F. dispar, F. francoi, and F. varia

Damage evolution in open-hole laminated composite plates subjected to in-plane loads

Damage evolution of notched composite laminates is analysed in this work using a discrete damage model, which estimates matrix damage evolution and fibre failure. The fibre damage is regularised with a Weibull distribution, and a Regula Falsi method has been used to improve numerical convergence. The model is compared and validated with several experimental results taken from the scientific literature, which consider different materials, laminate stacking sequences and specimen geometries. A good correlation has been found for the failure strength and the stress strain curve of notched and un-notched laminates subjected to in plane loads. The influence of the Weibull modulus on the matrix and fibre damage evolution, and the failure strength, is analysed.The authors are indebted for the financial support of this work to the Ministry of Economy and Competitiveness of Spain (project DPI2013 42240 R)