29,107 research outputs found
Enhanced photothermal displacement spectroscopy for thin-film characterization using a Fabry-Perot resonator
We have developed a technique for photothermal displacement spectroscopy that is potentially orders of magnitude more sensitive than conventional methods. We use a single Fabry-Perot resonator to enhance both the intensity of the pump beam and the sensitivity of the probe beam. The result is an enhancement of the response of the instrument by a factor proportional to the square of the finesse of the cavity over conventional interferometric measurements. In this paper we present a description of the technique, and we discuss how the properties of thin films can be deduced from the photothermal response. As an example of the technique, we report a measurement of the thermal properties of a multilayer dielectric mirror similar to those used in interferometric gravitational wave detectors
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Age-related changes to lumbosacral spinal cord motoneurons that modulate bladder and bowel functions in male C57BL/6 mice
Incontinence and sexual dysfunction are often increased in the aged human population. In rats and mice the pattern of micturition and faecal clearance also changes with ageing and is suggestive of bladder and bowel dysfunction
Blade loss transient dynamics analysis. Volume 3: User's manual for TETRA program
The users manual for TETRA contains program logic, flow charts, error messages, input sheets, modeling instructions, option descriptions, input variable descriptions, and demonstration problems. The process of obtaining a NASTRAN 17.5 generated modal input file for TETRA is also described with a worked sample
Structure, bonding and morphology of hydrothermally synthesised xonotlite
The authors have systematically investigated the role of synthesis conditions upon the structure and morphology of xonotlite. Starting with a mechanochemically prepared, semicrystalline phase with Ca/Si=1, the authors have prepared a series of xonotlite samples hydrothermally, at temperatures between 200 and 250 degrees C. Analysis in each case was by X-ray photoelectron spectroscopy, environmental scanning electron microscopy and X-ray diffraction. The authorsâ use of a much lower water/solid ratio has indirectly confirmed the âthrough solutionâ mechanism of xonotlite formation, where silicate dissolution is a key precursor of xonotlite formation. Concerning the role of temperature, too low a temperature (~200 degrees C) fails to yield xonotlite or leads to increased number of structural defects in the silicate chains of xonotlite and too high a temperature (>250 degrees C) leads to degradation of the xonotlite structure, through leaching of interchain calcium. Synthesis duration meanwhile leads to increased silicate polymerisation due to diminishing of the defects in the silicate chains and more perfect crystal morphologies
New nickel-base wrought superalloy with applications up to 1253 K (1800 F)
Alloy possesses combination of high tensile strength at low and intermediate temperatures to 1033 K with good rupture strength at high temperatures to 1255 K. Alloy has promise for turbine disk application in future gas turbine engines and for wrought integrally bladed turbine wheel; thickness and weight of disk portion of wheel could be reduced
Integrity bases for local invariants of composite quantum systems
Unitary group branchings appropriate to the calculation of local invariants
of density matrices of composite quantum systems are formulated using the
method of -function plethysms. From this, the generating function for the
number of invariants at each degree in the density matrix can be computed. For
the case of two two-level systems the generating function is . Factorisation of such series leads
in principle to the identification of an integrity basis of algebraically
independent invariants. This note replaces Appendix B of our paper\cite{us} J
Phys {\bf A33} (2000) 1895-1914 (\texttt{quant-ph/0001076}) which is incorrect.Comment: Latex, 4 pages, correcting Appendix B of quant-ph/0001076 Error in
corrected and conclusions modified accordingl
Risk of cancer following primary total hip replacement or primary resurfacing arthroplasty of the hip : A retrospective cohort study in Scotland
Acknowledgements: We are grateful to Lee Barnsdale, Doug Clark, and Richard Dobbie for advice and assistance with data preparation before analysis, and to the three anonymous referees for their helpful comments and suggestions.Peer reviewedPublisher PD
Progression and assessment in foreign languages at Key Stage 2
The teaching of primary languages has been increasing steadily, in response to the future entitlement for all Key Stage 2 (KS2) pupils aged 7-11 to learn a foreign language by 2010. However, there remain concerns about progression both within KS2 and through to secondary school and about how learners' progress is assessed. This paper presents findings on the issues of progression and assessment taken from case studies which formed part of a project funded by the then Department for Education and Skills (DfES), now the Department for Children, Schools and Families (DCSF). This project set out to evaluate 19 local authority (LA) Pathfinders in England that were piloting the introduction of foreign language learning at KS2 between 2003 and 2005. Findings revealed that there was inconsistency between schools, even within each LA Pathfinder, in the use of schemes of work and that assessment was generally underdeveloped in the majority of the Pathfinders. In order to set these findings in context, this paper examines the issues of progression and assessment in foreign language learning in England. Finally, it investigates the challenges English primary schools face in terms of progression and assessment in the light of the new entitlement and discusses implications for the future. Managing progression, both within KS2 and through to secondary school at KS3 (ages 11-14), is one of the key factors in determining the overall success of starting languages in primary school
Fluid-structure interaction simulation of flow-mediated dilation of a straight arterial conduit
Introduction Flow-mediated dilation (FMD) is a key non-invasive clinical assessment of endothelial dysfunction, an indicator of early atherosclerosis and cardiovascular diseases. FMD involves the measurement of an artery dilation, e.g. of the brachial, radial, femoral, or popliteal artery, induced by transient hyperaemia, following a temporary ischemic occlusion of a distal arterial segment. Such transient conditions, however, may also involve changes in the wall shear stress (WSS), blood pressure, and wall stiffness which have not been clearly established in relation to early vascular changes. This work aims to clarify the role of these flow-related mechanisms by investigating the haemodynamic environment of a straight arterial conduit with compliant walls during FMD. Methods By implementing a strongly-coupled fluid-structure interaction (FSI) solver within the open-source OpenFOAMextend library [1], the arterial vessel was modelled as a quarter cylinder with an in-vivo measured hyperaemic inflow condition (by [2]). The FSI solver follows a partitioned approach with separated solvers for fluid and structure, and an implicit coupling method between fluid and solid, with interface values being passed from one solver to the other. The solution of the fluid flow is based on the finite volume method (FVM), while the solid is solved by a Lagrangian FVM solver. The mesh motion for both the fluid and the solid, due to the interface displacement, is updated at every timestep using a dynamic mesh solver in OpenFOAM based on the Laplace equation discretisation. Prior examples of FSI simulations in OpenFOAM and the foam-extend project have demonstrated its use for cardiovascular flows [3]. Results & Discussion The results demonstrate the diameter change during FMD, while haemodynamic shear stresses and pressure values are also analysed. Current results are being used for correlating the displacement of the arterial walls and the prescribed in-vivo inlet velocity. Conclusion The methodology has been established for subsequent simulations. Future work will investigate the FMD in idealised and anatomically-correct bifurcated arterial models with prescribed ischemic occlusion of the distal branching arteries. It will also include the investigation of further haemodynamic metrics, such as the timeaveraged wall shear stress, the oscillatory shear index, and the transverse WSS, in comparison with in-vivo data. Acknowledgments This work is supported in part from the University of Strathclyde International Strategic Partner (ISP) Research Studentships, and the European Unionâs Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 749185. References 1. Extend-Project (2018) The foam-extend. https://sourceforge.net/projects/foam-extend/ 2. van Bussel, FCG et al. A control systems approach to quantify wall shear stress normalization by flowmediated dilation in the brachial artery. PloS one (2015) 10:e0115977 3. Tukovic, Zeljko, KaraËc, Aleksandar, Cardiff, Philip, Jasak, Hrvoje and Ivankovic, Alojz. (2018). OpenFOAM Finite Volume Solver for Fluid-Solid Interaction. Transactions of FA- MENA. 42. 1-31. 10.21278/TOF.42301
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