Intelligent pigments and plastics for CO2 detection

A novel CO2 intelligent pigment is incorporated into a thermoplastic polymer to create a long-lived CO2-sensitive plastic film which is characterised and then compared to a traditional solvent-based CO2 indicator film

Accommodating repair actions into gas turbine prognostics

Elements of gas turbine degradation, such as compressor fouling, are recoverable through maintenance actions like compressor washing. These actions increase the usable engine life and optimise the performance of the gas turbine. However, these maintenance actions are performed by a separate organization to those undertaking fleet management operations, leading to significant uncertainty in the maintenance state of the asset. The uncertainty surrounding maintenance actions impacts prognostic efficacy. In this paper, we adopt Bayesian on-line change point detection to detect the compressor washing events. Then, the event detection information is used as an input to a prognostic algorithm, advising an update to the estimation of remaining useful life. To illustrate the capability of the approach, we demonstrated our on-line Bayesian change detection algorithms on synthetic and real aircraft engine service data, in order to identify the compressor washing events for a gas turbine and thus provide demonstrably improved prognosis

NMR analysis of Nile Blue (C. I. Basic Blue 12) and Thionine (C. I. 52000) in solution

The dyes Nile Blue (C. I. Basic Blue 12, NB) and Thionine (C. I. 52000, TH) were examined in both ionic and neutral forms in different solvents using NMR and UV-visible Spectroscopy to firmly establish the structures of the molecules and to assess the nature and extent of their aggregating characteristics. 1H and 13C NMR assignments and chemical shift data were used along with (for NB) nuclear Overhauser effect information enabling a structure for self-assembly to be proposed. In both cases these data were supplemented with variable temperature, dilution and diffusion-based experimental results using 1H NMR spectroscopy thereby enabling the extended aggregate structures to be assessed in terms of the relative strength of self-association and the extent to which extended aggregates could form. Full and detailed solution phase NMR analysis of such dyes, especially the two studied in this context, have either not been widely reported or have not been studied to the depth presented here. The data and their interpretation form an important addition to the analysis of this class of dye compounds and provide additional insight into the effects of self-assembly on the behaviour of such molecules in various solution-phase environments

State-space models' dirty little secrets: even simple linear Gaussian models can have estimation problems

State-space models (SSMs) are increasingly used in ecology to model time-series such as animal movement paths and population dynamics. This type of hierarchical model is often structured to account for two levels of variability: biological stochasticity and measurement error. SSMs are flexible. They can model linear and nonlinear processes using a variety of statistical distributions. Recent ecological SSMs are often complex, with a large number of parameters to estimate. Through a simulation study, we show that even simple linear Gaussian SSMs can suffer from parameter- and state-estimation problems. We demonstrate that these problems occur primarily when measurement error is larger than biological stochasticity, the condition that often drives ecologists to use SSMs. Using an animal movement example, we show how these estimation problems can affect ecological inference. Biased parameter estimates of a SSM describing the movement of polar bears (\textit{Ursus maritimus}) result in overestimating their energy expenditure. We suggest potential solutions, but show that it often remains difficult to estimate parameters. While SSMs are powerful tools, they can give misleading results and we urge ecologists to assess whether the parameters can be estimated accurately before drawing ecological conclusions from their results

Comparative study of strain energy storage mechanisms between carbon fibre-reinforced peek and epoxy composites subjected to static and cyclic loading

Experimental studies were performed on the strain energy storage behaviour of aerospace grade PEEK and toughened epoxy carbon fibre-reinforced composite prepreg laminates having identical fibre content. The strain energy stored up to failure was recorded at the highest point of deflection for static three point bending (3PtB) samples laminates with different thicknesses. Ductile and brittle behaviors at failure have been the key focuses of this study therefore cyclic loading tests were also performed. Firstly, high strain 3PtB fatigue loading was carried out on the two prepregs with identical quasiisotropic stacking sequences, and secondly in order to characterise the plasticity parameters for the two laminates cyclic shear tests at high strain levels was carried out. The results have shown that the strain energy storage characteristics of the PEEK laminates are much better than those of the epoxy laminates in several ways; such as the independence of the strain energy storage level to thickness. Furthermore, at the same level of applied stress, the PEEK laminates tend not to lose strain energy compared to the toughened epoxy laminates. This study shows that the thermoplastic nature of the PEEK gives it an improved plasticity level which enhances its strain energy storage capability. PEEK carbon laminates are therefore serious candidates for spring applications

Turning points in a qualitatively different social space: young adults’ reflections of alternative provision

There is a wealth of evidence suggesting that after being marginalised and excluded from school young people who attend Alternative Provision settings report positive relationships and experiences of learning. There is however very little research which explores the longer term outcomes of attending this sort of provision. Retrospective life history interviews were undertaken with 18 young adults in their early to mid-20s who had attended Alternative Provision in England. Interviews focused on schooling, exclusion, attending Alternative Provision and the impact of this on what they had done since leaving school up to their present situation. Analysis showed that the experience of attending Alternative Provision frequently constituted a turning point in a young person’s life story. This was due to the qualitatively different kind of social space experienced there

Long-Period Giant Companions to Three Compact, Multiplanet Systems

Understanding the relationship between long-period giant planets and multiple smaller short-period planets is critical for formulating a complete picture of planet formation. This work characterizes three such systems. We present Kepler-65, a system with an eccentric (e = 0.28 ± 0.07) giant planet companion discovered via radial velocities (RVs) exterior to a compact, multiply transiting system of sub-Neptune planets. We also use precision RVs to improve mass and radius constraints on two other systems with similar architectures, Kepler-25 and Kepler-68. In Kepler-68 we propose a second exterior giant planet candidate. Finally, we consider the implications of these systems for planet formation models, particularly that the moderate eccentricity in Kepler-65\u27s exterior giant planet did not disrupt its inner system