Theoretical investigations of r-f induction heated plasmas

Radio frequency induction heated plasmas with power deposition and energy remova

Experimental investigation of the spectral emission characteristics of argon-tungsten and argon-uranium induction heated plasmas

Spectral emission characteristics of gaseous tungsten and uranium in induction heated argon plasma

Using subjective percentiles and test data for estimating fragility functions

Fragility functions are cumulative distribution functions (cdfs) of strengths at failure. They are needed for reliability analyses of systems such as power generation and transmission systems. Subjective opinions supplement sparse test data for estimating fragility functions. Often the opinions are opinions on the percentiles of the fragility function. Subjective percentiles are likely to be less biased than opinions on parameters of cdfs. Solutions to several problems in the estimation of fragility functions are found for subjective percentiles and test data. How subjective percentiles should be used to estimate subjective fragility functions, how subjective percentiles should be combined with test data, how fragility functions for several failure modes should be combined into a composite fragility function, and how inherent randomness and uncertainty due to lack of knowledge should be represented are considered. Subjective percentiles are treated as independent estimates of percentiles. The following are derived: least-squares parameter estimators for normal and lognormal cdfs, based on subjective percentiles (the method is applicable to any invertible cdf); a composite fragility function for combining several failure modes; estimators of variation within and between groups of experts for nonidentically distributed subjective percentiles; weighted least-squares estimators when subjective percentiles have higher variation at higher percents; and weighted least-squares and Bayes parameter estimators based on combining subjective percentiles and test data. 4 figures, 2 tables

Probabilistic approach to EMP assessment

The development of nuclear EMP hardness requirements must account for uncertainties in the environment, in interaction and coupling, and in the susceptibility of subsystems and components. Typical uncertainties of the last two kinds are briefly summarized, and an assessment methodology is outlined, based on a probabilistic approach that encompasses the basic concepts of reliability. It is suggested that statements of survivability be made compatible with system reliability. Validation of the approach taken for simple antenna/circuit systems is performed with experiments and calculations that involve a Transient Electromagnetic Range, numerical antenna modeling, separate device failure data, and a failure analysis computer program

How I reduce fuel consumption: An experimental study on mental models of eco-driving

Eco-driving has the potential to reduce fuel consumption and therefore emissions considerably. Previous research suggests that drivers have a certain level of eco-driving knowledge and skills, which they refrain from practising in their everyday lives. At the same time misconceptions and ambiguous messages from eco-driving support systems can confuse and demotivate. This research aimed to identify the mental models of eco-driving that regular drivers have. A driving simulator experiment with a varied road layout comprising urban and motorway sections was designed. The study used simple driving task instructions to investigate changes in the participants’ behaviour and thoughts in three conditions. Sixteen drivers were asked to ‘Drive normally’, ‘Drive safely’ or ‘Drive fuel-efficiently’. Behavioural measures, think aloud protocols and interviews were compared and analysed. The emphasis of this study was on eco-driving relevant indicators such as accelerating, braking, coasting and car-following. The results show that the participants do have mental models of eco-driving, which they did not use in the Baseline drive, when they were instructed to ‘Drive normally’. Misconceptions about speed and travel time provide the potential for more effective communication with the driver about the momentary efficient speed as well as resulting time losses and fuel savings. In addition, in-vehicle guidance can increase driving safety compared to practicing eco-driving without them

Screening for intracranial aneurysms in persons ⩾35 years with hypertension and atherosclerotic disease who smoke(d)

Introduction: Lifetime risk of aneurysmal subarachnoid haemorrhage (aSAH) is high (7%) in persons ⩾35 years with hypertension who smoke(d). Whether screening for intracranial aneurysms (IAs) to prevent aSAH is effective in these patients is unknown. Patients and methods: Participants were retrieved from a cohort of patients with clinically manifest atherosclerotic vascular disease included between 2012 and 2019 at the University Medical Centre Utrecht (SMART-ORACLE, NCT01932671) in whom CT-angiography (CTA) of intracranial arteries was performed. We selected patients ⩾35 years with hypertension who smoke(d). CTAs were reviewed for the presence of IAs by experienced neuroradiologists. Patients with IAs were offered follow-up imaging to detect aneurysmal growth. We determined aneurysm prevalence and developed a diagnostic model for IA risk at screening using multivariable logistic regression. Results: IA were found in 25 of 500 patients (5.0% prevalence, 95%CI: 3.3%–7.3%). Median 5 year risk of rupture assessed with the PHASES score was 0.9% (IQR: 0.7%–1.3%). During a median follow-up of 57 months (IQR: 39–83 months) no patients suffered from aSAH. Aneurysmal growth was detected in one patient for whom preventive treatment was advised. IA risk at screening ranged between 1.6% and 13.4% with predictors being age, female sex and current smoking. Discussion and conclusion: IA prevalence in persons ⩾35 years with hypertension and atherosclerotic vascular disease who smoke(d) was 5%. Given the very small proportion of IA that needed preventive treatment, we currently do not advise screening for Caucasian persons older than 35 years of age who smoke and have hypertension in general. Whether screening may be effective for certain subgroups (e.g. women older than 50 years of age) or other ethnic populations should be the subject of future studies