28,241 research outputs found
Integrated multilevel converter and battery management
A cascaded H-bridge multilevel converter is proposed as a BLDC drive incorporating real-time battery management. Intelligent H-bridges are used to monitor battery cells whilst simultaneously increasing their performance by reducing the variation between cells and controlling their discharge profiles
Hardware-in-the-loop tuning of a feedback controller for a buck converter using a GA
This paper presents a methodology for tuning a PID-based feedback controller for a buck converter using the ITAE controller performance index. The controller parameters are optimized to ensure that a reasonable transient response can be achieved whilst retaining stable operation. Experimental results demonstrate the versatility of the on-line tuning methodology
A cascaded H-bridge BLDC drive incorporating battery management
A multilevel BLDC drive is proposed using cascaded H-bridges with isolated sources to provide superior output waveforms and reduced current ripple whilst incorporating observer based SoC estimation. Energy management, based on SoC, is incorporated to improve battery performance, reduce variation between cells and to control charge/discharge profiles
Neutron Star Properties with Hyperons
In the light of the recent discovery of a neutron star with a mass accurately
determined to be almost two solar masses, it has been suggested that hyperons
cannot play a role in the equation of state of dense matter in
-equilibrium. We re-examine this issue in the most recent development of
the quark-meson coupling model. Within a relativistic Hartree-Fock approach and
including the full tensor structure at the vector-meson-baryon vertices, we
find that not only must hyperons appear in matter at the densities relevant to
such a massive star but that the maximum mass predicted is completely
consistent with the observation.Comment: Minor correction
Wave propagation through a coherently amplifying random medium
We report a detailed and systematic numerical study of wave propagation
through a coherently amplifying random one-dimensional medium. The coherent
amplification is modeled by introducing a uniform imaginary part in the site
energies of the disordered single-band tight binding Hamiltonian. Several
distinct length scales (regimes), most of them new, are identified from the
behavior of transmittance and reflectance as a function of the material
parameters. We show that the transmittance is a non-self-averaging quantity
with a well defined mean value. The stationary distribution of the super
reflection differs qualitatively from the analytical results obtained within
the random phase approximation in strong disorder and amplification regime. The
study of the stationary distribution of the phase of the reflected wave reveals
the reason for this discrepancy. The applicability of random phase
approximation is discussed. We emphasize the dual role played by the lasing
medium, as an amplifier as well as a reflector.Comment: 33 pages RevTex, 14 EPS figures included, Accepted for publication in
IJMP-
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Strength, Weakness, Opportunity, Threat (SWOT) Analysis of the Adaptations to Anatomical Education in the United Kingdom and Republic of Ireland in Response to the Covid‐19 Pandemic
The Covid-19 pandemic has driven the fastest changes to higher education across the globe, necessitated by social distancing measures preventing any face to face teaching. This has led to an almost immediate switch to distance learning by higher education institutions. Anatomy faces some unique challenges. Intrinsically, anatomy is a three-dimensional subject that requires a sound understanding of the relationships between structures, often achieved by the study of human cadaveric material, models and virtual resources. This study sought to identify the approaches taken in the United Kingdom and Republic of Ireland to deliver anatomical education through online means. Data were collected from 14 different universities in the United Kingdom and Republic of Ireland and compared adopting a thematic analysis approach. Once themes were generated, they were collectively brought together using a strength, weakness, opportunity, threat (SWOT) analysis. Key themes included the opportunity to develop new online resources and the chance to engage in new academic collaborations. Academics frequently mentioned the challenge that time constrains could place on the quality and effectiveness of these resources; especially as in many cases the aim of these resources is to compensate for a lack of exposure to cadaveric exposure. Comparisons of the actions taken by multiple higher education institutions reveals the ways that academics have tried to balance this demand. Discussions will facilitate decisions being made by higher education institutions regarding adapting the curriculum and assessment methods in anatomy
Ultra-high temperature measuring techniques Final report
Real time technique for measurement of high temperature gases and spectroscopic techniques for temperature measurement of hot cesium seeded hydroge
Bearing tester data compilation, analysis and reporting and bearing math modeling, volume 1
Thermal and mechanical models of high speed angular contact ball bearings operating in LOX and LN2 were developed and verified with limited test data in an effort to further understand the parameters that determine or effect the SSME turbopump bearing operational characteristics and service life. The SHABERTH bearing analysis program which was adapted to evaluate shaft bearing systems in cryogenics is not capable of accommodating varying thermal properties and two phase flow. A bearing model with this capability was developed using the SINDA thermal analyzer. Iteration between the SHABERTH and the SINDA models enable the establishment of preliminary bounds for stable operation in LN2. These limits were established in terms of fluid flow, fluid inlet temperature, and axial load for a shaft speed of 30,000 RPM
The management of poor performance in nursing and midwifery: a case for concern.
Aim(s) - To examine the evidence of how poorly performing nurses and midwives are managed in the UK NHS Background – There is little evidence about poor performance and its management in nursing and midwifery literature. Method(s) – The scoping study comprised a literature search, analysis of recent Nursing and Midwifery Council data and a day’s observation at NMC fitness to practice hearings. Results – Nurses and midwives are the clinical groups most likely to be suspended from work in the NHS; NHS Trusts do not report data on suspensions therefore no statistics exist on numbers, reasons for suspensions, managerial processes, gender, area of work, or ethnicity of those suspended; the few major research projects identify variable management practices regarding poor performance, the significant financial cost to the NHS and the personal cost to those suspended; there is some evidence that inexperienced, poorly trained, or poorly supported managers use suspension inappropriately. Our day of observation supported this.
Conclusion(s) – There is a need for more robust data gathering and research in the field of NHS managerial practice.
Implications for Nursing Management – Managers should refrain from adopting punitive forms of performance management. Both frontline staff and management need better training and support for dealing with poor performance
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