Nitric oxide formation in gas turbine combustion depends on four key factors: flame stabilization, heat transfer, fuel–air mixing and combustion instability. The design of modern gas turbine burners requires delicate compromises between fuel efficiency, emissions of oxides of nitrogen (NOx) and combustion stability. Burner designs allowing substantial NOx reduction are often prone to combustion oscillations. These oscillations also change the NOx fields. Being able to predict not only the main species field in a burner but also the pollutant and the oscillation levels is now a major challenge for combustion modelling. This must include a realistic treatment of unsteady acoustic phenomena (which create instabilities) and also of heat transfer mechanisms (convection and radiation) which control NOx generation.In this work, large-eddy simulation (LES) is applied to a realistic gas turbine combustion chamber configuration where pure methane is injected through multiple holes in a cone-shaped burner. In addition to a non-reactive simulation, this article presents three reactive simulations and compares them to experimental results. The first reactive simulation neglects effects of cooling air on flame stabilization and heat losses by radiation and convection. The second reactive simulation shows how cooling air and heat transfer affect nitric oxide emissions. Finally, the third reactive simulation shows the effects of combustion instability on nitric oxide emissions. Additionally, the combustion instability is analysed in detail, including the evaluation of the terms in the acoustic energy equation and the identification of the mechanism driving the oscillation.Results confirm that LES of gas turbine combustion requires not only an accurate chemical scheme and realistic heat transfer models but also a proper description of the acoustics in order to predict nitric oxide emissions and pressure oscillation levels simultaneously.

Purpose-The present study is concerned with the determinants of RFID adoption among a group of early standards adopters. Despite the extensive discussion of the technological characteristics and expected benefits of RFID in the literature, only little is known about the drivers and barriers of RFID implementations in practice. This holds particularly for the later stages of the adoption process after an initial decision in favor of the technology was made. This paper aims to fill this gap by an analysis of a set of factors on the adoption of RFID, which have been shown to be relevant for the adoption of other forms of IT, such as ERP systems and EDI. Design/methodology/approach-Based on a review of prior works, this paper constructs and empirically tests a structural model including factors related to the technology, the organization, and its environment. Findings-The results suggest that top management support, perceived technology costs, and forces within the supply chain exert a significant influence on the adoption process. The study also finds that benefit perceptions have a significant but negative influence, which might be explained by the different modes of adopting RFID. The influence of a number of other factors known from the literature could not be supported by the study. Originality/value-Prior works considered factors influencing the initial adoption decision among non-adopters. In contrast with these, the focus is set on research on early adopters that have already made a decision in favor of RFID standards. The data underlying this study were collected from EPCglobal, an international association of RFID adopters covering the whole supply chain.

ObjectiveTo assess whether the symptoms of veisalgia can be reduced by intense water supply and the intake of antioxidative supplements and plant extracts.MethodsWe performed the world’s largest randomised double-blind placebo-controlled intervention study (214 participants) on the efficacy of a food for special medical purposes (FSMP) against veisalgia symptoms. We analysed the effectiveness of: (1) an FSMP, including distinct plant extracts, vitamins and minerals, and additional (antioxidative) compounds; (2) a dietary supplement only comprising vitamins and minerals and additional (antioxidative) compounds; and (3) a placebo containing only glucose. The study followed the CONSORT (Consolidated Standards of Reporting Trials) guidelines and trial registration was not necessary.ResultsOur study showed no statistically significant relationship between the variation of body water content and alcohol consumption. Contrary to common belief, the results showed that intervention with a supplement containing vitamins and minerals and additional antioxidative compounds did not lead to a statistically significant improvement in hangover symptoms. Additionally, our results confirmed a high individual variability in developing hangover symptoms depending on the amount of alcohol. Thus, standardisation of the amount of alcohol consumed in hangover studies does not necessarily contribute to the validity of the results. Finally, this study found a number of positive effects on certain hangover symptoms as a result of the FSMP, which were most likely due to the plant extracts contained within the food.ConclusionThis study significantly supports the finding that haemostasis of electrolytes and minerals caused by alcohol consumption might be negligible and that no significant dehydration due to alcohol consumption seems to occur. Additionally, only the FSMP provides evidence for a significant efficiency in the reduction of hangover symptoms such as headache and nausea following moderate and non-excessive alcohol consumption.

BACKGROUND: To date, few data are available about severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence in young children and the role of early-life childcare arrangements in transmission of the virus. In this study, we assessed the SARS-CoV-2 seroprevalence in children less than 6 years of age in the canton of Fribourg and identified risk factors associated with seropositivity. METHODS: The COVPED study is a population-based cross-sectional study in children less than 6 years of age living in the canton of Fribourg, Switzerland, who presented to a private paediatrician or the paediatric emergency department of the Fribourg Hospital during a 9-week period between 11 January and 14 March 2021. Immunoglobulin G antibodies against SARS-CoV-2 trimeric spike protein were measured in capillary blood samples using an in-house Luminex assay. A mean fluorescence intensity ratio of above 6 was considered as positive. Metadata was collected through electronic questionnaires. Logistic regression analysis was performed to assess the risk of seropositivity and associated factors. RESULTS: A total of 871 children, with a median age of 33 months (range 6 days to 5 years 11 months) were included; 412 (47%) were female. Overall, 180 (21%, 95% confidence interval [CI] 18–24%) children were seropositive. Age as continuous variable was not associated with seropositivity risk, apart from a higher rate in children less than 3 months of age. Univariable analysis showed that female sex was associated with a lower seropositivity risk (unadjusted odds ratio [OR] 0.69, 95% CI 0.49–0.96; p = 0.03). Day-care attendance was also associated with a lower seropositivity risk (OR 0.67, 95% CI 0.47–0.95; p = 0.03), whereas all other childcare arrangements were not associated with seropositivity. No association was found between the number of children and adults present in extra-familial care and seropositivity. Multivariable analysis identified the number of household members above the age of 12 years being positive for SARS-CoV-2 as the main risk factor for seropositivity in children (adjusted odds ratio [aOR] 7.80, 95% CI 4.65–13.07; p <0.001 for one household member, aOR 22.07, 95% CI 13.49–36.11; p <0.001 for two household members and aOR 32.20, 95% CI 9.30–111.55; p <0.001 for three or more household members). CONCLUSION: The number of household members tested positive for SARS-CoV-2 (PCR test) is the main exposure risk to seropositivity for children less than 6 years of age. But the family size is not associated with an increased risk of infection. In young children, extra-familial care does not increase the risk of becoming SARS-CoV-2 seropositive, neither does the number of contacts present in extra-familial care. As adults and children will be vaccinated and new virus variants will be circulating the risk of exposure for young children will likely change and needs further monitoring.

A technical gas turbine combustor has been studied in detail with optical diagnostics for validation of large-eddy simulations (LES). OH* chemiluminescence, OH laser-induced fluorescence (LIF) and particle image velocimetry (PIV) have been applied to stable and pulsating flames up to 8 bar. The combination of all results yielded good insight into the combustion process with this type of burner and forms a database that was used for the validation of complex numerical combustion simulations. LES, including radiation, convective cooling, and air cooling, were combined with a reduced chemical scheme that predicts NOx emissions. Good agreement of the calculated flame position and shape with experimental data was found.