Flame interactions in turbulent premixed twin V-flames

Multiple flame-flame interactions in premixed combustion are investigated using Direct Numerical Simulations of twin turbulent V-flames for a range of turbulence intensities and length scales. Interactions are identified using a novel Automatic Feature Extraction (AFE) technique, based on data registration using the Dual-Tree Complex Wavelet Transform. Information on the time, position and type of interactions, and their influence on the flame area is extracted using AFE. Characteristic length and time scales for the interactions are identified. The effect of interactions on the flame brush is quantified through a global stretch rate, defined as the sum of flamelet stretch and interaction stretch contributions. The effects of each interaction type are discussed. It is found that the magnitude of the fluctuations in flamelet and interaction stretch are comparable, and a qualitative sensitivity to turbulence length scale is found for one interaction type. Implications for modelling are discussed.The authors would like to thank Professor R. S. Cant for the use of SENGA2. EPSRC funding through grant number EP/F028741/1, and funding from Rolls-Royce is acknowledged.This is an Accepted Manuscript of an article published by Taylor & Francis in Combustion Science and Technology on 16 January 2013, available online: http://wwww.tandfonline.com/10.1080/00102202.2012.713413

The effects of non-unity lewis numbers on turbulent premixed flame interactions in a twin V-flame configuration

The influence of Lewis number on turbulent premixed flame interactions is investigated using Automatic Feature Extraction (AFE) applied to high-resolution flame simulation data. Premixed turbulent twin V-flames under identical turbulence conditions are simulated at global Lewis numbers of 0.4, 0.8, 1.0 and 1.2. Information on the position, frequency and magnitude of the interactions is compared, and the sensitivity of the results to sample interval is discussed. It is found that both the frequency and magnitude of normal type interactions increases with decreasing Lewis number. Counter-normal type interactions become more likely as the Lewis number increases. The variation in both the frequency and the magnitude of the interactions is found to be caused by large-scale changes in flame wrinkling resulting from differences in the thermo-diffusive stability of the flames. During flame interactions thermo-diffusive effects are found to be insignificant due to the separation of time scales.EPSRC funding through grant number EP/F028741/1, and funding from Rolls-Royce is acknowledged.This is an Accepted Manuscript of an article published by Taylor & Francis in Combustion Science and Technology on 16 May 2013, available online: http://wwww.tandfonline.com/10.1080/00102202.2013.763801

Computation of Forced Premixed Flames Dynamics

Bluff body stabilised turbulent premixed flames subject to inlet velocity oscillation over a wide range of forcing frequency and amplitude are simulated using a flamelet-based combustion model. Two sets of detailed chemical kinetic schemes are used to model combustion chemistry. It is observed that the computed dynamics of forced flames agree reasonably well with experimental measurements. The flame elongation and shortening at a frequency of 40 Hz and strong flame-vortex interaction at a higher frequency of 160 Hz are captured well in the computations. The global flame describing function extracted from the computational results shows a linear response at 40 Hz and a nonlinear behaviour at 160 Hz as observed in the experiments. The nonlinear response is due to vortex roll-up and its subsequent shedding. The quantitative agreement of the computed flame describing function (FDF) with experimental measurement is uniformly good over a wide range of forcing frequency and amplitude. Some influence of chemical kinetics on the FDFs is observed, which mainly stems from the difference in laminar burning velocity and spatial heat release rate distribution.The support of Mitsubishi Heavy Industries, Takasago, Japan is acknowledged gratefully.This is the author accepted manuscript. The final version is available from Taylor & Francis via http://dx.doi.org/10.1080/00102202.2016.117411

Investigating the Causal Relationship of C-Reactive Protein with 32 Complex Somatic and Psychiatric Outcomes: A Large-Scale Cross-Consortium Mendelian Randomization Study

BACKGROUND: C-reactive protein (CRP) is associated with immune, cardiometabolic, and psychiatric traits and diseases. Yet it is inconclusive whether these associations are causal. METHODS AND FINDINGS: We performed Mendelian randomization (MR) analyses using two genetic risk scores (GRSs) as instrumental variables (IVs). The first GRS consisted of four single nucleotide polymorphisms (SNPs) in the CRP gene (GRSCRP), and the second consisted of 18 SNPs that were significantly associated with CRP levels in the largest genome-wide association study (GWAS) to date (GRSGWAS). To optimize power, we used summary statistics from GWAS consortia and tested the association of these two GRSs with 32 complex somatic and psychiatric outcomes, with up to 123,865 participants per outcome from populations of European ancestry. We performed heterogeneity tests to disentangle the pleiotropic effect of IVs. A Bonferroni-corrected significance level of less than 0.0016 was considered statistically significant. An observed p-value equal to or less than 0.05 was considered nominally significant evidence for a potential causal association, yet to be confirmed. The strengths (F-statistics) of the IVs were 31.92-3,761.29 and 82.32-9,403.21 for GRSCRP and GRSGWAS, respectively. CRP GRSGWAS showed a statistically significant protective relationship of a 10% genetically elevated CRP level with the risk of schizophrenia (odds ratio [OR] 0.86 [95% CI 0.79-0.94]; p < 0.001). We validated this finding with individual-level genotype data from the schizophrenia GWAS (OR 0.96 [95% CI 0.94-0.98]; p < 1.72 × 10-6). Further, we found that a standardized CRP polygenic risk score (CRPPRS) at p-value thresholds of 1 × 10-4, 0.001, 0.01, 0.05, and 0.1 using individual-level data also showed a protective effect (OR < 1.00) against schizophrenia; the first CRPPRS (built of SNPs with p < 1 × 10-4) showed a statistically significant (p < 2.45 × 10-4) protective effect with an OR of 0.97 (95% CI 0.95-0.99). The CRP GRSGWAS showed that a 10% increase in genetically determined CRP level was significantly associated with coronary artery disease (OR 0.88 [95% CI 0.84-0.94]; p < 2.4 × 10-5) and was nominally associated with the risk of inflammatory bowel disease (OR 0.85 [95% CI 0.74-0.98]; p < 0.03), Crohn disease (OR 0.81 [95% CI 0.70-0.94]; p < 0.005), psoriatic arthritis (OR 1.36 [95% CI 1.00-1.84]; p < 0.049), knee osteoarthritis (OR 1.17 [95% CI 1.01-1.36]; p < 0.04), and bipolar disorder (OR 1.21 [95% CI 1.05-1.40]; p < 0.007) and with an increase of 0.72 (95% CI 0.11-1.34; p < 0.02) mm Hg in systolic blood pressure, 0.45 (95% CI 0.06-0.84; p < 0.02) mm Hg in diastolic blood pressure, 0.01 ml/min/1.73 m2 (95% CI 0.003-0.02; p < 0.005) in estimated glomerular filtration rate from serum creatinine, 0.01 g/dl (95% CI 0.0004-0.02; p < 0.04) in serum albumin level, and 0.03 g/dl (95% CI 0.008-0.05; p < 0.009) in serum protein level. However, after adjustment for heterogeneity, neither GRS showed a significant effect of CRP level (at p < 0.0016) on any of these outcomes, including coronary artery disease, nor on the other 20 complex outcomes studied. Our study has two potential limitations: the limited variance explained by our genetic instruments modeling CRP levels in blood and the unobserved bias introduced by the use of summary statistics in our MR analyses. CONCLUSIONS: Genetically elevated CRP levels showed a significant potentially protective causal relationship with risk of schizophrenia. We observed nominal evidence at an observed p < 0.05 using either GRSCRP or GRSGWAS-with persistence after correction for heterogeneity-for a causal relationship of elevated CRP levels with psoriatic osteoarthritis, rheumatoid arthritis, knee osteoarthritis, systolic blood pressure, diastolic blood pressure, serum albumin, and bipolar disorder. These associations remain yet to be confirmed. We cannot verify any causal effect of CRP level on any of the other common somatic and neuropsychiatric outcomes investigated in the present study. This implies that interventions that lower CRP level are unlikely to result in decreased risk for the majority of common complex outcomes

Prevention of type 2 diabetes and its complications in developing countries: a review.

BACKGROUND: Type 2 diabetes mellitus (T2DM) is a significant global public health problem affecting more than 285 million people worldwide. Over 70% of those with T2DM live in developing countries, and this proportion is increasing annually. Evidence suggests that lifestyle and other nonpharmacological interventions can delay and even prevent the development of T2DM and its complications; however, to date, programs that have been specifically adapted to the needs and circumstances of developing countries have not been well developed or evaluated. PURPOSE: The purpose of this article is to review published studies that evaluate lifestyle and other non-pharmacological interventions aimed at preventing T2DM and its complications in developing countries. METHODS: We undertook an electronic search of MEDLINE, PubMed, and EMBASE with the English language restriction and published until 30 September 2009. RESULTS: Nine relevant publications from seven studies were identified. The reported interventions predominantly used counseling and educational methods to improve diet and physical activity levels. Each intervention was found to be effective in reducing the risk of developing T2DM in people with impaired glucose tolerance, and improving glycemic control in people with T2DM. CONCLUSIONS: The current evidence concerning the prevention of T2DM and its complications in developing countries has shown reasonably consistent and positive results; however, the small number of studies creates some significant limitations. More research is needed to evaluate the benefits of low-cost screening tools, as well as the efficacy, cost-effectiveness, and sustainability of culturally appropriate interventions in such countries

Women, sport and new media technologies:Derby grrrls online

Sport has long been viewed as a public ‘good’ — a space for the creation and enactment of the ‘good, healthy citizen’. Yet this public ‘good’ has also been gendered masculine: competitive, public and ‘tough’, with women’s participation historically marginal to men’s. In Australia in recent years, the participation of women and girls has fluctuated, with decline or stagnation in more traditional organised sports (netball, basketball) and growth in other areas, such as roller derby and football. However, women’s sports are still largely invisible in the popular sport media. In this chapter we focus on roller derby as one particular women’s sport that has undergone a global revival, mobilised through ‘new’ youth-oriented media forms. We examine four diverse websites that form part of the ‘social web’ of derby: two official league sites, a blog and a Facebook group. The reinvention of roller derby is intimately connected to the alternative mediated spaces made possible by the social web. Roller derby players and organisers have used online spaces for various ends: to promote the sport community, to make visible the relations of power between those involved, to create and maintain boundaries of inclusion and exclusion within the sport, and to express ‘creative’ aspects of identity. This chapter provides examples of the strategies and tactics used to establish and maintain roller derby as a ‘women’s only’ sport and some of the challenges and possibilities inherent in this highly mediated space.No Full Tex

Genetically elevated high-density lipoprotein cholesterol through the cholesteryl ester transfer protein gene does not associate with risk of Alzheimer's disease

Introduction: There is conflicting evidence whether high-density lipoprotein cholesterol (HDL-C) is a risk factor for Alzheimer's disease (AD) and dementia. Genetic variation in the cholesteryl ester transfer protein (CETP) locus is associated with altered HDL-C. We aimed to assess AD risk by genetically predicted HDL-C. Methods: Ten single nucleotide polymorphisms within the CETP locus predicting HDL-C were applied to the International Genomics of Alzheimer's Project (IGAP) exome chip stage 1 results in up 16,097 late onset AD cases and 18,077 cognitively normal elderly controls. We performed instrumental variables analysis using inverse variance weighting, weighted median, and MR-Egger. Results: Based on 10 single nucleotide polymorphisms distinctly predicting HDL-C in the CETP locus, we found that HDL-C was not associated with risk of AD (P > .7). Discussion: Our study does not support the role of HDL-C on risk of AD through HDL-C altered by CETP. This study does not rule out other mechanisms by which HDL-C affects risk of AD