Mixing along the Red Giant Branch in Metal-poor Field Stars

We have determined Li, C, N, O, Na, and Fe abundances, and 12C/13C isotopic ratios for a sample of 62 field metal-poor stars (plus 43 taken from the literature). This large sample was used to show that small mass lower-RGB stars (i.e., fainter than the RGB bump) have abundances of light elements in agreement with theoretical predictions from classical evolutionary models. A second, distinct mixing episode occurs just after the RGB bump, reaching regions of incomplete CNO burning. No O-Na anticorrelation, as observed in globular cluster stars, is found in field stars. This means that the mixing episode is not deep enough to reach regions where ON-burning occurs.Comment: 6 pages, 3 encapsulated figures, LateX, uses crckapb.sty; invited talk, in "The Chemical Evolution of the Milky Way: Stars vs Clusters, Vulcano (Italy), 20-24 September 1999, F. Matteucci and F. Giovannelli eds, Kluwer, in pres

Structural integrity assessment of the welded joints of the constitution of 1812 bridge (Cádiz, Spain)

As required by the current Spanish regulations, an inspection and maintenance plan has been completed for the Constitution of 1812 Bridge over the Bay of Cádiz (Spain), which defines the work to be performed on the different elements of the bridge during its service life. The part of the plan related to the inspection of the steel structure has a section dedicated to the inspection of the defects that may be present in the welded joints of the steel deck, providing critical defect sizes above which the safety of the structure would be compromised. With this purpose, in the most stressed points of the deck, the structural details that are most susceptible to fatigue and fracture phenomena have been identified. Moreover, fatigue tests of these details have been performed to complete a structural integrity assessment that also comprises the determination of the material fracture toughness and the definition of the corresponding critical crack sizes. The tests were carried out on specimens obtained with the same steel grades as those used in the bridge and with the same welding procedures as those practiced in the structure. The results show that the fatigue test results are above the SN curves provided by the Eurocode 3, and also that numerous critical crack sizes would not be detected by the usual inspection techniques used in bridges (visual inspection), so that further research into how to manage this issue is recommended.The authors of this work would like to express their gratitude to the University of Cantabria for the financial support of the project “Aplicación de Técnicas de Integridad Estructural y Fiabilidad de Materiales en la Determinacion del Ciclo de Vida de Puentes Metalicos y Mixtos- Application of Structural Integrity and Materials Reliability Techniques to the Life-Cycle Assessment of Metallic and Steel-Concrete Composite Bridges” (03.DI09.649), programme of industrial doctorates, on the results of which this paper is based

Livestock trade networks for guiding animal health surveillance

BACKGROUND: Trade in live animals can contribute to the introduction of exotic diseases, the maintenance and spread endemic diseases. Annually millions of animals are moved across Europe for the purposes of breeding, fattening and slaughter. Data on the number of animals moved were obtained from the Directorate General Sanco (DG Sanco) for 2011. These were converted to livestock units to enable direct comparison across species and their movements were mapped, used to calculate the indegrees and outdegrees of 27 European countries and the density and transitivity of movements within Europe. This provided the opportunity to discuss surveillance of European livestock movement taking into account stopping points en-route. RESULTS: High density and transitivity of movement for registered equines, breeding and fattening cattle, breeding poultry and pigs for breeding, fattening and slaughter indicates that hazards have the potential to spread quickly within these populations. This is of concern to highly connected countries particularly those where imported animals constitute a large proportion of their national livestock populations, and have a high indegree. The transport of poultry (older than 72 hours) and unweaned animals would require more rest breaks than the movement of weaned animals, which may provide more opportunities for disease transmission. Transitivity is greatest for animals transported for breeding purposes with cattle, pigs and poultry having values of over 50%. CONCLUSIONS: This paper demonstrated that some species (pigs and poultry) are traded much more frequently and at a larger scale than species such as goats. Some countries are more vulnerable than others due to importing animals from many countries, having imported animals requiring rest-breaks and importing large proportions of their national herd or flock. Such knowledge about the vulnerability of different livestock systems related to trade movements can be used to inform the design of animal health surveillance systems to facilitate the trade in animals between European member states. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12917-015-0354-4) contains supplementary material, which is available to authorized users

Resonant amplification of vortex-core oscillations by coherent magnetic-field pulses

Vortex structures in soft magnetic nanodisks are highly attractive due to their scientific beauty and potential technological applications. Here, we experimentally demonstrated the resonant amplification of vortex oscillations by application of simple coherent field pulses tuned to optimal width and time intervals. In order to investigate vortex excitations on the sub-ns time scale, we employed state-of-the-art time-resolved full-field soft X-ray microscopy of 70 ps temporal and 25 nm lateral resolution. We found that, due to the resonant enhancement of the vortex gyration motion, the signal input power can be significantly reduced to similar to 1 Oe in field strength, while increasing signal gains, by increasing the number of the optimal field pulses. We identified the origin of this behavior as the forced resonant amplification of vortex gyration. This work represents an important milestone towards the potential implementation of vortex oscillations in future magnetic vortex devices.open4

An experimental and analytical investigation of reinforced concrete beam-column joints strengthened with a range of CFRP schemes applied only to the beam

This paper investigates the experimental and analytical behaviour of beam-column joints that are subjected to a combination of torque, flexural and direct shear forces, where different Carbon Fibre Polymer (CFRP) strengthening wraps have been applied only to the beam. These wrapping schemes have previously been determined by the research community as an effective method of enhancing the torsional capacities of simply supported reinforced concrete beams. In this investigation, four 3/4-scale exterior beam-column joints were subjected to combined monotonic loading; three different beam wrapping schemes were employed to strengthen the beam region of the joint. The paper suggests a series of rational formulae, based on the space truss mechanism, which can be used to evaluate the joint shear demand of the beams wrapped in these various ways. Further, an iterative model, based on the average stress-strain method, has been introduced to predict joint strength. The proposed analytical approaches show good agreement with the experimental results. The experimental outcomes along with the adopted analytical methods reflect the consistent influence of the wrapping ratio, the interaction between the combined forces, the concrete strut capacity and the fibre orientation on the joint forces, the failure mode and the distortion levels. A large rise in the strut force resulting from shear stresses generated from this combination of forces is demonstrated and leads to a sudden-brittle failure. Likewise, increases in the beams’ main steel rebar strains are identified at the column face, again influenced by the load interactions and the wrapping systems used

S-N curve for riveted details in corrosive environment and its application to a bridge

A formula for stress‐life curve is proposed to predict the fatigue life of riveted bridges located in corrosive environments. The corrosive environment‐dependent parameters of the S‐N curve are determined based on the corrosion fatigue testing results of different types of steel specimens in air, fresh water, and seawater. Eurocode detail category 71 and UK WI‐rivet detail category represent the fatigue strength of riveted members. The proposed S‐N curve formula is compared with full‐scale fatigue test results of riveted joints, plate girders, and truss girders, which were tested in a corrosive environment. Thus, the validity of the formula is confirmed. The formula does not require any material parameter other than the code‐given fatigue curve of riveted details. The fatigue life of a riveted railway bridge is estimated by using the proposed formula, and the results are compared with conventional approaches. The applicability and significance of the proposed curve are confirmed.publishedVersio