47 research outputs found

    On-chip beam rotators, polarizers and adiabatic mode converters through low-loss waveguides with variable cross-sections

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    Photonics integrated circuitry would benefit considerably from the ability to arbitrarily control waveguide cross-sections with high precision and low loss, in order to provide more degrees of freedom in manipulating propagating light. Here, we report on a new optical-fibres-compatible glass waveguide by femtosecond laser writing, namely spherical phase induced multi-core waveguide (SPIM-WG), which addresses this challenging task with three dimensional on-chip light control. Precise deformation of cross-sections is achievable along the waveguide, with shapes and sizes finely controllable of high resolution in both horizontal and vertical transversal directions. We observed that these waveguides have high refractive index contrast of 0.017, low propagation loss of 0.14 dB/cm, and very low coupling loss of 0.19 dB coupled from a single mode fibre. SPIM-WG devices were easily fabricated that were able to perform on-chip beam rotation through varying angles, or manipulate polarization state of propagating light for target wavelengths. We also demonstrated SPIM-WG mode converters that provide arbitrary adiabatic mode conversion with high efficiency between symmetric and asymmetric non-uniform modes; examples include circular, elliptical modes and asymmetric modes from ppKTP waveguides which are generally applied in frequency conversion and quantum light sources. Created inside optical glass, these waveguides and devices have the capability to operate across ultra-broad bands from visible to infrared wavelengths. The compatibility with optical fibre also paves the way toward packaged photonic integrated circuitry, which usually needs input and output fibre connections

    HealtheStepsâ„¢ Study Protocol: a pragmatic randomized controlled trial promoting active living and healthy lifestyles in at-risk Canadian adults delivered in primary care and community-based clinics

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    Abstract Background Physical inactivity is one of the leading causes of chronic disease in Canadian adults. With less than 50% of Canadian adults reaching the recommended amount of daily physical activity, there is an urgent need for effective programs targeting this risk factor. HealtheSteps™ is a healthy lifestyle prescription program, developed from an extensive research base to address risk factors for chronic disease such as physical inactivity, sedentary behaviour and poor eating habits. HealtheSteps™ participants are provided with in-person lifestyle coaching and access to eHealth technologies delivered in community-based primary care clinics and health care organizations. Method/Design To determine the effectiveness of Healthesteps™, we will conduct a 6-month pragmatic randomized controlled trial with integrated process and economic evaluations of HealtheSteps™ in 5 clinic settings in Southwestern Ontario. 110 participants will be individually randomized (1:1; stratified by site) to either the intervention (HealtheSteps™ program) or comparator (Wait-list control). There are 3 phases of the HealtheSteps™ program, lasting 6 months each. The active phase consists of bi-monthly in-person coaching with access to a full suite of eHealth technology supports. During the maintenance phase I, the in-person coaching will be removed, but participants will still have access to the full suite of eHealth technology supports. In the final stage, maintenance phase II, access to the full suite of eHealth technology supports is removed and participants only have access to publicly available resources and tools. Discussion This trial aims to determine the effectiveness of the program in increasing physical activity levels and improving other health behaviours and indicators, the acceptability of the HealtheSteps™ program, and the direct cost for each person participating in the program as well as the costs associated with delivering the program at the different community sites. These results will inform future optimization and scaling up of the program into additional community-based primary care sites. Trial registration NCT02413385 (Clinicaltrials.gov). Date Registered: April 6, 2015

    Diameter Quality Control of Nb3Sn Wires for MQXF Cables in the USA

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    The future of the external audit function

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    The future of the external audit function

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    Competitiveness of the audit services market

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    The future of the external audit function

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    Purpose – The purpose of this paper is to provide an overview of the challenges and opportunities currently facing external auditors at a time of economic and financial crisis. Design/methodology/approach – The paper has a particular focus on the other contributions to this special issue of Managerial Auditing Journal and provides a reflective synthesis of these while making reference to other relevant literature as appropriate. Findings – The paper puts forward various suggestions for future academic research that might improve auditing practice. Also, the principal aim of this special issue has been to spotlight differing perspectives on some of the perennial problems which have plagued auditing for generations and to suggest possible ways forward. Practical implications – Various suggestions for future academic research that might improve auditing practice are put forward in the paper. Originality/value – Major contemporary issues facing the auditing profession (or industry) are summarized. The paper highlights the diversity of value stances that exists in the audit academy and may (together with the other papers forming part of this special issue) be useful for introducing university students studying auditing at intermediate or advanced levels to a variety of current auditing issues and debates.Auditors, External auditing

    Cu-Ti Formation in Nb-Ti/Cu Superconducting Strand Monitored by in situ Techniques

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    In order to investigate the high temperature exposure effect on Nb-Ti/Cu superconducting strands, as might be encountered in joining by soldering and in cabling annealing, X-ray diffraction and resistometry measurements were performed in situ during heat treatment, and complemented by conventional metallography, mechanical tests and superconducting properties measurements. Changes of the Nb-Ti nanostructure at temperatures above 300 degrees C are manifested in the degradation of critical current in an applied external magnetic field, although degradation at self field was insignificant up to 400 degrees C for several minutes. Above 500 degrees C, the formation of various Cu-Ti intermetallic compounds, due to Ti diffusion from Nb-Ti into Cu, is detected by in situ XRD albeit not resolvable by SEM-EDS. There is a ductile to brittle transition near 600 degrees C, and liquid formation is observed below 900 degrees C. The formation of Cu-Ti causes a delayed reduction of the residual resistivity ratio (RRR) and adversely affects the deformation behaviour of the strands
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