Rotational 3D Printing of Sensor Devices using Reactive Ink Chemistries

This paper charts progress in three key areas of a project supported by both UK government and UK industry to manufacture novel sensor devices using rotary 3D printing technology and innovative ink chemistries; (1) the development of an STL file slicing algorithm that returns constant Z height 2D contour data at a resolution that matches the given print head setup, allowing digital images to be generated of the correct size without the need for scaling; (2) the development of image transformation algorithms which allow images to be printed at higher resolutions using tilted print heads and; (3) the formulation of multi part reaction inks which combine and react on the substrate to form solid material layers with a finite thickness. A Direct Light Projection (DLP) technique demonstrated the robustness of the slice data by constructing fine detailed three dimensional test pieces which were comparable to identical parts built in an identical way from slice data obtained using commercial software. Material systems currently under investigation include plaster, stiff polyamides and epoxy polymers and conductive metallic’s. Early experimental results show conductivities of silver approaching 1.42x105 Siemens/m.Mechanical Engineerin

Calibration and Cross-Validation of Accelerometery for Estimating Movement Skills in Children Aged 8-12 Years

This study sought to calibrate triaxial accelerometery, worn on both wrists, waist and both ankles, during children’s physical activity (PA), with particular attention to object control motor skills performed at a fast and slow cadence, and to cross-validate the accelerometer cut-points derived from the calibration using an independent dataset. Twenty boys (10.1 ±1.5 years) undertook seven, five-minute bouts of activity lying supine, standing, running (4.5kmph−1) instep passing a football (fast and slow cadence), dribbling a football (fast and slow cadence), whilst wearing five GENEActiv accelerometers on their non-dominant and dominant wrists and ankles and waist. VO2 was assessed concurrently using indirect calorimetry. ROC curve analysis was used to generate cut-points representing sedentary, light and moderate PA. The cut-points were then cross-validated using independent data from 30 children (9.4 ± 1.4 years), who had undertaken similar activities whilst wearing accelerometers and being assessed for VO2. GENEActiv monitors were able to discriminate sedentary activity to an excellent level irrespective of wear location. For moderate PA, discrimination of activity was considered good for monitors placed on the dominant wrist, waist, non-dominant and dominant ankles but fair for the non-dominant wrist. Applying the cut-points to the cross-validation sample indicated that cut-points validated in the calibration were able to successfully discriminate sedentary behaviour and moderate PA to an excellent standard and light PA to a fair standard. Cut-points derived from this calibration demonstrate an excellent ability to discriminate children’s sedentary behaviour and moderate intensity PA comprising motor skill activity.N/

Decoherence of a Josephson qubit due to coupling to two level systems

Noise and decoherence are major obstacles to the implementation of Josephson junction qubits in quantum computing. Recent experiments suggest that two level systems (TLS) in the oxide tunnel barrier are a source of decoherence. We explore two decoherence mechanisms in which these two level systems lead to the decay of Rabi oscillations that result when Josephson junction qubits are subjected to strong microwave driving. (A) We consider a Josephson qubit coupled resonantly to a two level system, i.e., the qubit and TLS have equal energy splittings. As a result of this resonant interaction, the occupation probability of the excited state of the qubit exhibits beating. Decoherence of the qubit results when the two level system decays from its excited state by emitting a phonon. (B) Fluctuations of the two level systems in the oxide barrier produce fluctuations and 1/f noise in the Josephson junction critical current I_o. This in turn leads to fluctuations in the qubit energy splitting that degrades the qubit coherence. We compare our results with experiments on Josephson junction phase qubits.Comment: 23 pages, Latex, 6 encapsulated postscript figure

Refinement of atomic models in high resolution EM reconstructions using Flex-EM and local assessment

As the resolutions of Three Dimensional Electron Microscopic reconstructions of biological macromolecules are being improved, there is a need for better fitting and refinement methods at high resolutions and robust approaches for model assessment. Flex-EM/MODELLER has been used for flexible fitting of atomic models in intermediate-to-low resolution density maps of different biological systems. Here, we demonstrate the suitability of the method to successfully refine structures at higher resolutions (2.5–4.5 Å) using both simulated and experimental data, including a newly processed map of Apo-GroEL. A hierarchical refinement protocol was adopted where the rigid body definitions are relaxed and atom displacement steps are reduced progressively at successive stages of refinement. For the assessment of local fit, we used the SMOC (segment-based Manders’ overlap coefficient) score, while the model quality was checked using the Qmean score. Comparison of SMOC profiles at different stages of refinement helped in detecting regions that are poorly fitted. We also show how initial model errors can have significant impact on the goodness-of-fit. Finally, we discuss the implementation of Flex-EM in the CCP-EM software suite

Stellar twins determine the distance of the Pleiades

© 2016 ESO.Since the release of the Hipparcos catalogue in 1997, the distance to the Pleiades open cluster has been heavily debated. The distance obtained from Hipparcos and those by alternative methods differ by 10 to 15%. As accurate stellar distances are key to understanding stellar structure and evolution, this dilemma puts the validity of some stellar evolution models into question. Using our model-independent method to determine parallaxes based on twin stars, we report individual parallaxes of 15 FGK type stars in the Pleiades in anticipation of the astrometric mission Gaia. These parallaxes give a mean cluster parallax of 7.42 ± 0.09 mas,which corresponds to a mean cluster distance of 134.8 ± 1.7 pc. This value agrees with the current results obtained from stellar evolution models

Kondo Insulators Modeled by the One Dimensional Anderson Lattice: A Numerical Renormalization Group Study

In order to better understand Kondo insulators, we have studied both the symmetric and asymmetric Anderson lattices at half-filling in one dimension using the density matrix formulation of the numerical renormalization group. We have calculated the charge gap, spin gap and quasiparticle gap as a function of the repulsive interaction U using open boundary conditions for lattices as large as 24 sites. We find that the charge gap is larger than the spin gap for all U for both the symmetric and asymmetric cases. RKKY interactions are evident in the f-spin-f-spin correlation functions at large U in the symmetric case, but are suppressed in the asymmetric case as the f-level approaches the Fermi energy. This suppression can also be seen in the staggered susceptibility and it is consistent with neutron scattering measurements in CeNiSn.Comment: 32 pages, Latex file with Postcript figures

Autobiographical memory, autonoetic consciousness, and identity in Asperger syndrome

Previous results from research on individuals with Asperger syndrome (AS) suggest a diminished ability for recalling episodic autobiographical memory (AM). The primary aim of this study was to explore autobiographical memory in individuals with Asperger syndrome and specifically to investigate whether memories in those with AS are characterized by fewer episodic 'remembered' events (due to a deficit in autonoetic consciousness). A further aim was to examine whether such changes in AM might also be related to changes in identity, due to the close relationship between memory and the self and to the established differences in self-referential processes in AS. Eleven adults with AS and fifteen matched comparison participants were asked to recall autobiographical memories from three lifetime periods and for each memory to give either a remember response (autonoetic consciousness) or a know response (noetic consciousness). The pattern of results shows that AS participants recalled fewer memories and that these memories were more often rated as known, compared to the comparison group. AS participants also showed differences in reported identity, generating fewer social identity statements and more abstract, trait-linked identities. The data support the view that differences in both memory and reported personal identities in AS are characterized by a lack of specificity

UK science press officers, professional vision and the generation of expectations

Science press officers can play an integral role in helping promote expectations and hype about biomedical research. Using this as a starting point, this article draws on interviews with 10 UK-based science press officers, which explored how they view their role as science reporters and as generators of expectations. Using Goodwin’s notion of ‘professional vision’, we argue that science press officers have a specific professional vision that shapes how they produce biomedical press releases, engage in promotion of biomedical research and make sense of hype. We discuss how these insights can contribute to the sociology of expectations, as well as inform responsible science communication.This project was funded by the Wellcome Trust (Wellcome Trust Biomedical Strategic Award 086034)

Meso-scale defect evaluation of selective laser melting using spatially resolved acoustic spectroscopy

Developments in additive manufacturing technology are serving to expand the potential applications. Critical developments are required in the supporting areas of measurement and in process inspection to achieve this. CM247LC is a nickel superalloy that is of interest for use in aerospace and civil power plants. However, it is difficult to process via selective laser melting (SLM) as it suffers from cracking during rapid cooling and solidification. This limits the viability of CM247LC parts created using SLM. To quantify part integrity, spatially resolved acoustic spectroscopy (SRAS) has been identified as a viable non-destructive evaluation technique. In this study, a combination of optical microscopy and SRAS was used to identify and classify the surface defects present in SLM-produced parts. By analysing the datasets and scan trajectories, it is possible to correlate morphological information with process parameters. Image processing was used to quantify porosity and cracking for bulk density measurement. Analysis of surface acoustic wave data showed that an error in manufacture in the form of an overscan occurred. Comparing areas affected by overscan with a bulk material, a change in defect density from 1.17% in the bulk material to 5.32% in the overscan regions was observed, highlighting the need to reduce overscan areas in manufacture