Peak Stir Zone Temperatures during Friction Stir Processing

The stir zone (SZ) temperature cycle was measured during the friction stir processing (FSP) of NiAl bronze plates. The FSP was conducted using a tool design with a smooth concave shoulder and a 12.7-mm step-spiral pin. Temperature sensing was accomplished using sheathed thermocouples embedded in the tool path within the plates, while simultaneous optical pyrometry measurements of surface temperatures were also obtained. Peak SZ temperatures were 990 ⁰Cto 1015 ⁰C (0.90 to 0.97 TMelt) and were not affected by preheating to 400⁰C, although the dwell time above 900 ⁰C was increased by the preheating. Thermocouple data suggested little variation in peak temperature across the SZ, although thermocouples initially located on the advancing sides and at the centerlines of the tool traverses were displaced to the retreating sides, precluding direct assessment of the temperature variation across the SZ. Microstructure-based estimates of local peak SZ temperatures have been made on these and on other similarly processed materials. Altogether, the peak-temperature determinations from these different measurement techniques are in close agreement

Use of a trabecular metal implant in ankle arthrodesis after failed total ankle replacement: A short-term follow-up of 13 patients

Patients and methods 13 patients with a migrated or loose total ankle implant underwent arthrodesis with the use of a retrograde intramedullary nail through a trabecular metal Tibial Cone. The mean follow-up time was 1.4 (0.6-3.4) years. Results At the last examination, 7 patients were pain-free, while 5 had some residual pain but were satisfied with the procedure. 1 patient was dissatisfied and experienced pain and swelling when walking. The implant-bone interfaces showed no radiographic zones or gaps in any patient, indicating union. Interpretation The method is a new way of simplifying and overcoming some of the problems of performing arthrodesis after failed total ankle replacement

Network centrality and organizational aspirations: A behavioral interaction in the context of international strategic alliances

Whereas social network analysis has been associated with organizational aspirations, little is known on how firm's structural positioning, and particularly network centrality, affects organizational aspirations to engage in international strategic alliances (ISA). This study examines the impact of network centrality on firm's internationalization behavior within the ISA domain in response to the performance-aspiration gap. We build on social and behavioral perspectives to predict that network centrality and performance-based aspirations will be associated with the number of ISA the firm engages in. Using a sample of 7760 alliance collaborations from the top 81 global pharmaceutical firms for the period of 1991-2012, we find supporting evidence for most of our arguments

Clean catalogues of blue horizontal-branch stars using

Context. Blue horizontal-branch stars evolve from low-mass stars that have completed their main-sequence lifetimes and undergone a helium flash at the end of their red-giant phase. As such, blue horizontal-branch stars are very old objects that can be used as markers in studies of the Galactic structure and formation history. To create a clean sky catalogue of blue horizontal-branch stars, we cross-matched the Gaia data release 2 (DR2) dataset with existing reference catalogues to define selection criteria based on Gaia DR2 parameters. Following the publication of Gaia early data release 3 (EDR3), these methods were verified and subsequently applied to this latest release. Aims. Previous catalogues of blue horizontal-branch stars were developed using spectral analyses or were restricted to individual globular clusters. The purpose of this catalogue is to identify a set of blue horizontal-branch star candidates that have been selected using photometric and astrometric observations and exhibits a low contamination rate. This has been deemed important as the success of the Gaia mission has changed the way that targets are selected for large-scale spectroscopic surveys, meaning that far fewer spectra will be acquired for blue horizontal-branch stars in the future unless they are specifically targeted. Methods. We cross-matched reference blue horizontal-branch datasets with the Gaia DR2 database and defined two sets of selection criteria. Firstly, in Gaia DR2 – colour and absolute G magnitude space, and secondly, in Gaia DR2 – colour and reduced proper motion space. The main-sequence contamination in both subsets of the catalogue was reduced, at the expense of completeness, by concentrating on the Milky Way’s Galactic halo, where relatively young main-sequence stars were not expected. The entire catalogue is limited to those stars with no apparent neighbours within 5 arcsec. These methods were verified and subsequently applied to the Gaia EDR3. Results. We present a catalogue, based on Gaia EDR3, of 57 377 blue horizontal-branch stars. The Gaia EDR3 parallax was used in selecting 16 794 candidates and the proper motions were used to identify a further 40 583 candidates

The metabolic profiling of exercise intervention: exercise metabolomics

In exercise intervention science, the nascent fields of exercise ‘omics’ (metabolomics and proteomics) encompass the identification, characterisation, and quantification of the changes over time for metabolite and protein content of whole cells, tissues, or body fluids. In order to establish the current status, a literature search was completed using a metasearch engine linked to academic database resources using a combination of the keywords; ‘exercise’, ‘sport’, ‘intervention’, ‘metabol*’ which resulted in 235 potential studies. The search was refined to relevance based on the following inclusion criteria: healthy human subjects; exercise/training intervention; analysis of targeted or untargeted metabolites in muscle, blood or urine; published between 1999-2011. Studies were excluded that concerned animal subjects, humans diagnosed with mechanical or medical problems, no exercise/training intervention, diet-based intervention or nutritional studies, reviews, abstracts without full-text available and duplicates. These inclusion/exclusion criteria were used to select relevant studies to extract and compare data on the change in metabolites induced by exercise intervention, and compare the analytical techniques used over the past 12years. The refined search resulted in a final selection of eighteen studies that were reviewed. Data on study design, populations, exercise intervention, outcome measures and analytical techniques, were compiled and analysed. Studies have been reported for targeted and nontargeted biological profiling of blood and urine, based mostly on gas chromatography-mass spectrometry (GC-MS) and high performance liquid chromatography-mass spectrometry (LC-MS). Standardised protocols for sampling and analysis are at an early stage and few studies report chemometric analysis of the data. GC-MS and nuclear magnetic resonance (NMR) spectrometry data for urine, plasma and saliva from baseline studies in our laboratory are presented. AL acknowledges a PhD scholarship from the School of Health, Sport and Bioscience, University of East London Where applicable, the authors confirm that the experiments described here conform with The Physiological Society ethical requirements