Pre-notched and corroded low cycle fatigue behaviour of a nickel based alloy for disc rotor applications

Currently there is doubt surrounding the suitability of chemically-induced stress independent pre-conditioning of specimens to simulate turbine corrosion prior to fatigue testing. the thick oxide scales developed using such techniques can lead to net section loss and typically a lack of grain boundary sulphide attack seen in components that experience stress. An alternative approach to a corrosion-fatigue test scenario is suggested by micro-notching fatigue specimens prior to low salt flux corrosion to form grain boundary sulphide particles within channel-like features akin to stress assisted morphologies. On fatigue testing, a trend was identified where a change of mechanism was observed. The grain boundary oxide likely formed in the wake of freshly precipitated sulphide particles fractures around segments of grains leading to a metal loss that contributes to a significant reduction in fatigue properties

Risk-Sensitive Mean-Field Type Control under Partial Observation

We establish a stochastic maximum principle (SMP) for control problems of partially observed diffusions of mean-field type with risk-sensitive performance functionals.Comment: arXiv admin note: text overlap with arXiv:1404.144

On the use of stochastic spectral methods in deep excavation inverse problems

The back analysis or inverse analysis of the field instrumentation data is a common technique to ascertain the design parameter validity in deep excavation projects. That analysis is a process full of uncertainties and relies greatly on the expert judgement. Furthermore, deep excavation geotechnical models tend to be computationally very expensive making the inverse analysis a very lengthy process. In this paper, a Bayesian-type methodology to solve inverse problems which relies on the reduction of the numerical cost of the forward simulation through stochastic spectral surrogate models is presented. The proposed methodology is validated with three calibration examples.Canavate-Grimal, A.; Falcó, A.; Calderón García, PA.; Paya-Zaforteza, I. (2015). On the use of stochastic spectral methods in deep excavation inverse problems. Computers and Structures. 159:41-60. doi:10.1016/j.compstruc.2015.06.009S416015

Medico-legal autopsy in postoperative hemodynamic collapse following coronary artery bypass surgery

Sudden unexpected postoperative hemodynamic collapse with a high mortality develops in 1–3% of patients undergoing coronary artery bypass surgery (CABG). The contribution of surgical graft complications to this serious condition is poorly known and their demonstration at autopsy is a challenging task. Isolated CABG was performed in 8,807 patients during 1988–1999. Of the patients, 76 (0.9%) developed sudden postoperative hemodynamic collapse resulting in subsequent emergency reopening of the median sternotomy and open cardiac massage. Further emergency reoperation could be performed in 62 (82%) whereas 14 patients died prior to reoperation and a further 21 did not survive the reoperation or died a few days later. All 35 (46%) patients who did not survive were subjected to medico-legal autopsy combined with postmortem cast angiography. By combining clinical data with autopsy and angiography data, various types of graft complications were observed in 27 (36%, 1.3 per patient) of the 76 patients with hemodynamic collapse. There were no significant differences in the frequency (33 vs. 40%) or number of complicated grafts per patient (1.2 vs. 1.4) between those who survived reoperation and who did not. Autopsy detected 25 major and minor findings not diagnosed clinically. Postmortem cast angiography visualized 2 graft twists not possible to detect by autopsy dissection only. Surgical graft complications were the most frequent single cause for sudden postoperative hemodynamic collapse in CABG patients leading to a fatal outcome in almost half of the cases. Postmortem angiography improved the accuracy of autopsy diagnostics of graft complications

How Might Crime-Scripts Be Used to Support the Understanding and Policing of Cloud Crime?

Crime scripts are becoming an increasingly popular method for understanding crime by turning a crime from a static event into a process, whereby every phase of the crime is scripted. It is based on the work relating to cognitive scripts and rational-choice theory. With the exponential growth of cyber-crime, and more specifically cloud-crime, policing/law enforcement agencies are struggling with the amount of reported cyber-crime. This paper argues that crime scripts are the most effective way forward in terms of helping understand the behaviour of the criminal during the crime itself. They act as a common language between different stakeholders, focusing attention and resources on the key phases of a crime. More importantly, they shine a light on the psychological element of a crime over the more technical cyber-related elements. The paper concludes with an example of what a cloud-crime script might look like, asking future research to better understand: (i) cloud criminal fantasy development; (ii) the online cultures around cloud crime; (iii) how the idea of digital-drift affects crime scripts, and; (iv) to improve on the work by Ekblom and Gill in improving crime scripts