Power System Plant Modelling from PRBS Experiments

This work is part of a collaborative exercise between the Department of Control Engineering, University of Sheffield, the Department of Electronic Engineering, University of Leeds and the CEGB Scientific Services Department, N.E Region. Increasing availability of cheap, fast, reliable, localised computing power renders feasible the on-line control of a broad class of systems. Whether as a precursor to decision of control strategy, a tool for simulation studies or a means of fault detection, system identification is being increasingly pursued..........

Quantum field dynamics of the slow rollover in the linear delta expansion

We show how the linear delta expansion, as applied to the slow-roll transition in quantum mechanics, can be recast in the closed time-path formalism. This results in simpler, explicit expressions than were obtained in the Schr\"odinger formulation and allows for a straightforward generalization to higher dimensions. Motivated by the success of the method in the quantum-mechanical problem, where it has been shown to give more accurate results for longer than existing alternatives, we apply the linear delta expansion to four-dimensional field theory. At small times all methods agree. At later times, the first-order linear delta expansion is consistently higher that Hartree-Fock, but does not show any sign of a turnover. A turnover emerges in second-order of the method, but the value of $$at the turnover is larger that that given by the Hartree-Fock approximation. Based on this calculation, and our experience in the corresponding quantum-mechanical problem, we believe that the Hartree-Fock approximation does indeed underestimate the value of$$ at the turnover. In subsequent applications of the method we hope to implement the calculation in the context of an expanding universe, following the line of earlier calculations by Boyanovsky {\sl et al.}, who used the Hartree-Fock and large-N methods. It seems clear, however, that the method will become unreliable as the system enters the reheating stage.Comment: 17 pages, 9 figures, revised version with extra section 4.2 including second order calculatio

Integrating sequence and array data to create an improved 1000 Genomes Project haplotype reference panel

A major use of the 1000 Genomes Project (1000GP) data is genotype imputation in genome-wide association studies (GWAS). Here we develop a method to estimate haplotypes from low-coverage sequencing data that can take advantage of single-nucleotide polymorphism (SNP) microarray genotypes on the same samples. First the SNP array data are phased to build a backbone (or 'scaffold') of haplotypes across each chromosome. We then phase the sequence data 'onto' this haplotype scaffold. This approach can take advantage of relatedness between sequenced and non-sequenced samples to improve accuracy. We use this method to create a new 1000GP haplotype reference set for use by the human genetic community. Using a set of validation genotypes at SNP and bi-allelic indels we show that these haplotypes have lower genotype discordance and improved imputation performance into downstream GWAS samples, especially at low-frequency variants. © 2014 Macmillan Publishers Limited. All rights reserved

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Mathematical Modelling of Power Station Plant the Role of Simulation

The role of simulation in an exercise aimed at identification and verification of mathematical models of the principle control loops of pulverised fuel mills feeding the furnace of a large coal-fired power station is described. Models of this type are an essential precursor to decision of control strategy, controller design and optimization and to development and monitoring of alarm systems for operator assistance. Design of the experimental program and choice of excitation sequence is described., together with detection of the plant structure and estimation of the model coefficients. Development of a simulation, incorporating a range of associated control systems, is discussed and uses to which the simulation may be put are reviewed

Identification of Mill Dynamics from Normal Operating Records

This report describes plant modelling based on data collected during routine operation at a large coal-fired power station in the north of England. Data from one of the eight pulverised fuel mills which feed the furnace of one of the generating units was recorded continuously on magnetic tape and sampled using a digital computer at the University

Controlled reduction of vanadium oxide nanoscrolls: crystal structure, morphology, and electrical properties

The systematic and controlled reduction of vanadium oxide nanoscrolls results in routes to the large-scale preparation of nanostructures of the interesting and useful materials rutile VO2 and corundum V2O3. Vanadium oxide (V2O5−δ) nanoscrolls, prepared by the hydrothermal treatment of aged suspensions of V2O5 and dodecylamine, were reduced in a furnace in an atmosphere of 5% H2:95% N2 under different time and temperature conditions to monitor systematic trends in the structure and morphology of the resulting oxides. The products were characterized by X-ray diffraction (XRD), electron microscopy, N2 sorption measurements, and electrical transport studies. We find that the reduction conditions (time and temperature) play a significant role in determining the crystal structure and morphology of the products. At short times and low temperatures, the reduction products are rutile VO2. These convert to corundum V2O3 when temperatures are increased. In all cases, the appearance of crystalline Bragg peaks in XRD is associated with the breaking up of the starting high-aspect nanostructures into small, dense crystallites. Under certain reduction conditions, porous materials with ill-defined X-ray structures are obtained as intermediates