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Computation of the field in an axial gap, trapped-flux type superconducting electric machine
The Bulk Superconductivity Group at the University
of Cambridge is currently investigating the use of high temperature
superconductors in wire and bulk form to increase the
electrical and magnetic loading of an axial gap, trapped flux-type
superconducting electric machine. The use of superconducting
materials in electric machines can lead to increases in efficiency,
as well as power density, which results in reductions in both the
size and weight of the machine. In this paper, the authors present a
method to compute the field in such an electric machine generated
by an array of fully magnetized bulk superconductors. Analytical
expressions are derived for the field that would exist in the coil
region of the motor, which will act as a powerful tool for carrying
out parametric analysis of the motor’s design and performance.This work was supported in part by a Royal Academy of Engineering Research
Fellowship and by the China Scholarship Council.This is the accepted manuscript. The final version is available from IEEE at http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6945871
Aristelliger praesignis (Jamaican Croaking Lizard). Maximum Size.
This article is available as on open access publication downloadable from the Society for the Study of Amphibians and Reptiles website https://ssarherps.org/herpetological-review-pdfs/. The attached file is the published pdf
Identification of Boundary Conditions Using Natural Frequencies
The present investigation concerns a disc of varying thickness of whose
flexural stiffness varies with the radius according to the law , where and are constants. The problem of finding boundary
conditions for fastening this disc, which are inaccessible to direct
observation, from the natural frequencies of its axisymmetric flexural
oscillations is considered. The problem in question belongs to the class of
inverse problems and is a completely natural problem of identification of
boundary conditions. The search for the unknown conditions for fastening the
disc is equivalent to finding the span of the vectors of unknown conditions
coefficients. It is shown that this inverse problem is well posed. Two theorems
on the uniqueness and a theorem on stability of the solution of this problem
are proved, and a method for establishing the unknown conditions for fastening
the disc to the walls is indicated. An approximate formula for determining the
unknown conditions is obtained using first three natural frequencies. The
method of approximate calculation of unknown boundary conditions is explained
with the help of three examples of different cases for the fastening the disc
(rigid clamping, free support, elastic fixing).
Keywords: Boundary conditions, a disc of varying thickness,inverse problem,
Plucker condition.Comment: 19 page
Applications of interpretability in deep learning models for ophthalmology
PURPOSE OF REVIEW: In this article, we introduce the concept of model interpretability, review its applications in deep learning models for clinical ophthalmology, and discuss its role in the integration of artificial intelligence in healthcare. RECENT FINDINGS: The advent of deep learning in medicine has introduced models with remarkable accuracy. However, the inherent complexity of these models undermines its users' ability to understand, debug and ultimately trust them in clinical practice. Novel methods are being increasingly explored to improve models' 'interpretability' and draw clearer associations between their outputs and features in the input dataset. In the field of ophthalmology, interpretability methods have enabled users to make informed adjustments, identify clinically relevant imaging patterns, and predict outcomes in deep learning models. SUMMARY: Interpretability methods support the transparency necessary to implement, operate and modify complex deep learning models. These benefits are becoming increasingly demonstrated in models for clinical ophthalmology. As quality standards for deep learning models used in healthcare continue to evolve, interpretability methods may prove influential in their path to regulatory approval and acceptance in clinical practice
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A superconducting magnetic gear
A comparison is made between a magnetic gear using permanent magnets and superconductors. The objective is to see if there are any fundamental reasons why superconducting magnets should not provide higher power densities than permanent magnets. The gear is based on the variable permeability design of Attilah and Howe (2001 IEEE Trans. Magn. 37 2844–46) in which a ring of permanent magnets surrounding a ring of permeable pole pieces with a different spacing gives an internal field component at the beat frequency. Superconductors can provide much larger fields and forces but will saturate the pole pieces. However the gear mechanism still operates, but in a different way. The magnetisation of the pole pieces is now constant but rotates with angle at the beat frequency. The result is a cylindrical Halbach array which produces an internal field with the same symmetry as in the linear regime, but has an analytic solution. In this paper a typical gear system is analysed with finite elements using FlexPDE. It is shown that the gear can work well into the saturation regime and that the Halbach array gives a good approximation to the results. Replacing the permanent magnets with superconducting tapes can give large increases in torque density, and for something like a wind turbine a combined gear and generator is possible. However there are major practical problems. Perhaps the most fundamental is the large high frequency field which is inevitably present and which will cause AC losses. Also large magnetic fields are required, with all the practical problems of high field superconducting magnets in rotating machines. Nevertheless there are ways of mitigating these difficulties and it seems worthwhile to explore the possibilities of this technology further
Urinary Sodium Excretion and Blood Pressure Relationship across Methods of Evaluating the Completeness of 24-h Urine Collections
We compared the sodium intake and systolic blood pressure (SBP) relationship from complete 24-h urine samples determined by several methods: self-reported no-missed urine, creatinine index ≥0.7, measured 24-h urine creatinine (mCER) within 25% and 15% of Kawasaki predicted urine creatinine, and sex-specific mCER ranges (mCER 15–25 mg/kg/24-h for men; 10–20 mg/kg/24-h for women). We pooled 10,031 BP and 24-h urine sodium data from 2143 participants. We implemented multilevel linear models to illustrate the shape of the sodium–BP relationship using the restricted cubic spline (RCS) plots, and to assess the difference in mean SBP for a 100 mmol increase in 24-h urine sodium. The RCS plot illustrated an initial steep positive sodium–SBP relationship for all methods, followed by a less steep positive relationship for self-reported no-missed urine, creatinine index ≥0.7, and sex-specific mCER ranges; and a plateaued relationship for the two Kawasaki methods. Each 100 mmol/24-h increase in urinary sodium was associated with 0.64 (95% CI: 0.34, 0.94) mmHg higher SBP for self-reported no-missed urine, 0.68 (95% CI: 0.27, 1.08) mmHg higher SBP for creatinine index ≥0.7, 0.87 (95% CI: 0.07, 1.67) mmHg higher SBP for mCER within 25% Kawasaki predicted urine creatinine, 0.98 (95% CI: −0.07, 2.02) mmHg change in SBP for mCER within 15% Kawasaki predicted urine creatinine, and 1.96 (95% CI: 0.93, 2.99) mmHg higher SBP for sex-specific mCER ranges. Studies examining 24-h urine sodium in relation to health outcomes will have different results based on how urine collections are deemed as complete
Techno-economic evaluation of reducing shielding gas consumption in GMAW whilst maintaining weld quality
A new method of supplying shielding gases in an alternating manner has been developed to enhance the efficiency of conventional gas metal arc welding (GMAW). However, the available literature on this advanced joining process is very sparse and no cost evaluation has been reported to date. In simple terms, the new method involves discretely supplying two different shielding gases to the weld pool at predetermined frequencies which creates a dynamic action within the liquid pool. In order to assess the potential benefits of this new method from a technical and cost perspective, a comparison has been drawn between the standard shielding gas composition of Ar/20%CO2, which is commonly used in UK and European shipbuilding industries for carbon steels, and a range of four different frequencies alternating between Ar/20%CO2 and helium. The beneficial effects of supplying the weld shielding gases in an alternating manner were found to provide attractive benefits for the manufacturing community. For example, the present study showed that compared with conventional GMAW, a 17 per cent reduction in total welding cost was achieved in the case of the alternating gas method and savings associated with a reduction in the extent of post-weld straightening following plate distortion were also identified. Also, the mechanical properties of the alternating case highlighted some marginal improvements in strength and Charpy impact toughness which were attributed to a more refined weld microstructure
{\phi}^4 Solitary Waves in a Parabolic Potential: Existence, Stability, and Collisional Dynamics
We explore a {\phi}^4 model with an added external parabolic potential term.
This term dramatically alters the spectral properties of the system. We
identify single and multiple kink solutions and examine their stability
features; importantly, all of the stationary structures turn out to be
unstable. We complement these with a dynamical study of the evolution of a
single kink in the trap, as well as of the scattering of kink and anti-kink
solutions of the model. We see that some of the key characteristics of
kink-antikink collisions, such as the critical velocity and the multi-bounce
windows, are sensitively dependent on the trap strength parameter, as well as
the initial displacement of the kink and antikink
TERC polymorphisms are associated both with susceptibility to colorectal cancer and with longer telomeres.
Shorter telomeres have been associated with increased risk of malignancy, including colorectal cancer (CRC). Telomere length is heritable and may be an intermediate phenotype linked to genetic susceptibility to CRC
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