Computational alternatives to obtain time optimal jet engine control

Two computational methods to determine an open loop time optimal control sequence for a simple single spool turbojet engine are described by a set of nonlinear differential equations. Both methods are modifications of widely accepted algorithms which can solve fixed time unconstrained optimal control problems with a free right end. Constrained problems to be considered have fixed right ends and free time. Dynamic programming is defined on a standard problem and it yields a successive approximation solution to the time optimal problem of interest. A feedback control law is obtained and it is then used to determine the corresponding open loop control sequence. The Fletcher-Reeves conjugate gradient method has been selected for adaptation to solve a nonlinear optimal control problem with state variable and control constraints

Millisecond single-molecule localization microscopy combined with convolution analysis and automated image segmentation to determine protein concentrations in complexly structured, functional cells, one cell at a time

We present a single-molecule tool called the CoPro (Concentration of Proteins) method that uses millisecond imaging with convolution analysis, automated image segmentation and super-resolution localization microscopy to generate robust estimates for protein concentration in different compartments of single living cells, validated using realistic simulations of complex multiple compartment cell types. We demonstrates its utility experimentally on model Escherichia coli bacteria and Saccharomyces cerevisiae budding yeast cells, and use it to address the biological question of how signals are transduced in cells. Cells in all domains of life dynamically sense their environment through signal transduction mechanisms, many involving gene regulation. The glucose sensing mechanism of S. cerevisiae is a model system for studying gene regulatory signal transduction. It uses the multi-copy expression inhibitor of the GAL gene family, Mig1, to repress unwanted genes in the presence of elevated extracellular glucose concentrations. We fluorescently labelled Mig1 molecules with green fluorescent protein (GFP) via chromosomal integration at physiological expression levels in living S. cerevisiae cells, in addition to the RNA polymerase protein Nrd1 with the fluorescent protein reporter mCherry. Using CoPro we make quantitative estimates of Mig1 and Nrd1 protein concentrations in the cytoplasm and nucleus compartments on a cell-by-cell basis under physiological conditions. These estimates indicate a 4-fold shift towards higher values in concentration of diffusive Mig1 in the nucleus if the external glucose concentration is raised, whereas equivalent levels in the cytoplasm shift to smaller values with a relative change an order of magnitude smaller. This compares with Nrd1 which is not involved directly in glucose sensing, which is almost exclusively localized in the nucleus under high and..

The emergence of magnetic flux through a partially ionised solar atmosphere

We present results from 2.5D numerical simulations of the emergence of magnetic flux from the upper convection zone through the photosphere and chromosphere into the corona. Certain regions of the solar atmosphere are at sufficiently low temperatures to be only partially ionised, in particular the lower chromosphere. This leads to Cowling resistivities orders of magnitude larger than the Coulomb values, and thus to anisotropic dissipation in Ohm’s law. This also leads to localised low magnetic Reynolds numbers (R m < 1). We find that the rates of emergence of magnetic field are greatly increased by the partially ionised regions of the model atmosphere, and the resultant magnetic field is more diffuse. More importantly, the only currents associated with the magnetic field to emerge into the corona are aligned with the field, and thus the newly formed coronal field is force-free

Alternatives for Jet Engine Control

Approaches are developed as alternatives to current design methods which rely heavily on linear quadratic and Riccati equation methods. The main alternatives are discussed in two broad categories, local multivariable frequency domain methods and global nonlinear optimal methods

Ergonomic standards for pedestrian areas for disabled people: literature review and consultations

As part of the project for the Transport and Road Research Laboratory concerned with the development of design guidance for pedestrian areas and footways to satisfy the needs of disabled and elderly people, a thorough examination of the literature was required. In addition the literature search was to be complemented by a wide-ranging series of discussions with local authorities, organisations representing the interests of elderly and disabled people, and other interested agencies. This Working Paper sets out the findings of this exercise. The objective of the literature review and the consultations was to identify the key impediments for elderly and disabled people when using pedestrian areas and footways. The current guidelines and standards relating to footways, pedestrianised areas and access to buildings were to be identified and their adequacy commented upon, as were the conflicts such recommendations raise between various groups of disabled people and with able-bodied people. The consultations were intended to provide greater insights into what the literature highlighted, and to suggest possible solutions. The literature review produced over 400 key references and a list of 35 impediments. A more detailed examination of the literature and the consultations reduced this list to six key impediments namely: parking; public transport waiting areas; movement distances; surface conditions; ramps, and information provision. The type and scale of problem created by the above impediments for various groups of disabled and elderly people are discussed, together with their measurement and assessment. The type and adequacy of existing design standards and guidance relating to these impediments are also outlined

Ergonomic Standards for Pedestrian Areas for Disabled People: Methodology and Sample Identification

This project is a TRRL research contract, the aim of which is to produce guidance on the design of pedestrian areas and footways for elderly and disabled people. The first part of the project was a literature review and consultation exercise, the objective of which was to identify key impediments for investigation. The second part of the project involved the detailed survey work on the key impediments. This Working Paper reports upon the development of the second part of the project and, in particular, upon the identification of the sample of disabled people to be used in the detailed interview and observation work. The sample identification involved contacting some 3000 disabled people listed in official disability registers, and 250 ablebodied people via on-street interviews. From the disabled sample approximately 500 people were interviewed in order to find out more about their disability and to assess the usefulness of a preliminary disability categorisation system; their activity rate; problems they experience in using pedestrian areas and footways; and their willingness to take part in further stages of the study. From the interviews, a sample of people in each of the revised categories, together with samples of the elderly and the ablebodied, were selected for an observation phase in which those involved were observed completing a movement distance exercise, and using different types of pedestrian facility, in central Leeds

Economic Standards for Pedestrian Areas for Disabled People: Results from Observation Work

1.1.1 The Institute for Transport Studies was invited by the Transport and Road Research Laboratory to submit a research proposal, with costs, aimed at establishing suitable "Ergonomic Standards for Pedestrian Areas for Disabled People". The project commenced on 1st July, 1986 and was split into two parts, with part one involving four months' work over the period to 31st December, 1986 and part two finishing on 30th April, 1988. 1.1.2 The -objectives of the study laid down in the design brief by the Transport and Road Research Laboratory were: a) To produce a guide to good practice for the design and maintenance of footways and pedestrianised areas; b) To provide, where possible, recommended standards for design and maintenance. The good practice guide and the recommended standards were to be primarily aimed at disabled people and the elderly, but the requirements of the able-bodied were also to be considered, as were conflicts between the needs of different groups of user. The economic implications of implementation and maintenance were also to be detailed. (Continues..