A novel linear direct drive system for textile winding applications

The paper describes the specification, modelling, magnetic design, thermal characteristics and control of a novel, high acceleration (up to 82g) brushless PM linear actuator with Halbach array, for textile package winding applications. Experimental results demonstrate the realisation of the actuator and induced performance advantages afforded to the phase lead, closed-loop position control scheme

An experimental laboratory bench setup to study electric vehicle antilock braking / traction systems and their control

This paper describes the preliminary research and implementation of an experimental test bench set up for an electric vehicle antilock braking system (ABS)/traction control system (TCS) representing the dry, wet and icy road surfaces. A fuzzy logic based controller to control the wheel slip for electric vehicle antilock braking system is presented. The test facility comprised of an induction machine load operating in the generating region. The test facility was used to simulate a variety of tire/road μ-σ driving conditions, eliminating the initial requirement for skid-pan trials when developing algorithms. Simulation studies and results are provided

Application of Fuzzy control algorithms for electric vehicle antilock braking/traction control systems

Abstract—The application of fuzzy-based control strategies has recently gained enormous recognition as an approach for the rapid development of effective controllers for nonlinear time-variant systems. This paper describes the preliminary research and implementation of a fuzzy logic based controller to control the wheel slip for electric vehicle antilock braking systems (ABSs). As the dynamics of the braking systems are highly nonlinear and time variant, fuzzy control offers potential as an important tool for development of robust traction control. Simulation studies are employed to derive an initial rule base that is then tested on an experimental test facility representing the dynamics of a braking system. The test facility is composed of an induction machine load operating in the generating region. It is shown that the torque-slip characteristics of an induction motor provides a convenient platform for simulating a variety of tire/road - driving conditions, negating the initial requirement for skid-pan trials when developing algorithms. The fuzzy membership functions were subsequently refined by analysis of the data acquired from the test facility while simulating operation at a high coefficient of friction. The robustness of the fuzzy-logic slip regulator is further tested by applying the resulting controller over a wide range of operating conditions. The results indicate that ABS/traction control may substantially improve longitudinal performance and offer significant potential for optimal control of driven wheels, especially under icy conditions where classical ABS/traction control schemes are constrained to operate very conservatively

Quantifying parasitic losses from metal scattering structures in solar cells: How uncertainty in optical constants affects simulation results

The optical constants of many metals commonly used in solar cells, e.g. as contacts or for light trapping structures, are not documented consistently in the literature, with different sources giving different values. In the case of metallic structures designed to improve absorption in a solar cell junction, the use of data from different sources can give strongly varying results for the effectiveness of nanophotonic light-trapping structures. The trade-off between diffraction into more oblique orders in the junction, enhancing absorption in the photovoltaic material, and the number of photons absorbed parasitically in the metal means small differences in the optical constants can lead to different very conclusions about the EQE and J SC . This work documents the different optical constants for silver, aluminium, gold and titanium from several sources, the effect this has on plasmon quality factors, and quantifies the effect on modelling outcomes by considering the optimization of a test structure using a grid of metal nanodisks on the front surface of a thinned-down GaAs cell. Finally, we consider the effect for a structure previously predicted to give a very high J SC for a solar cell with an ultra-thin GaAs layer

Towards operational measures of computer security

Ideally, a measure of the security of a system should capture quantitatively the intuitive notion of ‘the ability of the system to resist attack’. That is, it should be operational, reflecting the degree to which the system can be expected to remain free of security breaches under particular conditions of operation (including attack). Instead, current security levels at best merely reflect the extensiveness of safeguards introduced during the design and development of a system. Whilst we might expect a system developed to a higher level than another to exhibit ‘more secure behaviour’ in operation, this cannot be guaranteed; more particularly, we cannot infer what the actual security behaviour will be from knowledge of such a level. In the paper we discuss similarities between reliability and security with the intention of working towards measures of ‘operational security’ similar to those that we have for reliability of systems. Very informally, these measures could involve expressions such as the rate of occurrence of security breaches (cf rate of occurrence of failures in reliability), or the probability that a specified ‘mission’ can be accomplished without a security breach (cf reliability function). This new approach is based on the analogy between system failure and security breach. A number of other analogies to support this view are introduced. We examine this duality critically, and have identified a number of important open questions that need to be answered before this quantitative approach can be taken further. The work described here is therefore somewhat tentative, and one of our major intentions is to invite discussion about the plausibility and feasibility of this new approach

Editorial: Implausible discussions in saturated fat 'research'; definitive solutions won't come from another million editorials (or a million views of one).

The British Journal of Sports Medicine published an opinion editorial advocating a revision of public health guidance on saturated fat.1 Here, we offer a rebuttal, incorporating evidence-based principles absent in the original editorial, focusing on the quality of the evidence presented and we discuss contradictory evidence in relation to saturated fat, low-density lipoprotein cholesterol (LDL-C), specific dietary interventions and cardiovascular disease (CVD) alongside future directions

Cocoa and chocolate, their clinical benefits:Insights in study design

Randomized controlled trials and meta-analyses have demonstrated the potential protective effect of cocoa and chocolate consumption with respect to cardiovascular disease (CVD) risk markers. Findings from experimental studies are in concordance with observational data, which include reduction in clinical disease (especially stroke) being associated with chocolate consumption. However, the effect size of any benefit, and the exact mechanism of action due to variability in reporting of dose and type potential bioactive compounds remains unclear. Thus, the present review aimed to analyse the published work where cocoa and chocolate have been assessed for their potential to protect against CVD and highlight the role of study design and type of product used in the variances of outcomes and how that might be used in formulating health advice

ExoMol line lists – XLVIII. High-temperature line list of thioformaldehyde (H2CS)

A comprehensive rotation-vibration (ro-vibrational) line list of thioformaldehyde (1H212C32S) that is applicable for elevated temperatures (2000K) is presented. The new MOTY line list covers the 0 to 8000 cm−1 range (wavelengths λ > 1.3μm and contains around 43.5billion transitions between 52.3million states with rotational excitation up to J = 120. Line list calculations utilise a newly determined empirically refined potential energy surface (PES) – the most accurate H2CS PES to date – a previously published high-level ab initio dipole moment surface, and the use of an exact kinetic energy operator for solving the ro-vibrational Schrödinger equation. Post-processing of the MOTY line list is performed by replacing calculated energy levels with empirically-derived values, vastly improving the accuracy of predicted line positions in certain spectral windows and making the line list suitable for high-resolution applications. The MOTY line list is available from the ExoMol database at www.exomol.com and the CDS astronomical database