Prediction of flame velocities of hydrocarbon flames

The laminar-flame-velocity data previously reported by the Lewis Laboratory are surveyed with respect to the correspondence between experimental flame velocities and values predicted by semitheoretical and empirical methods. The combustible mixture variables covered are hydrocarbon structure (56 hydrocarbons), equivalence ratio of fuel-air mixture, mole fraction of oxygen in the primary oxygen-nitrogen mixture (0.17 to 0.50), and initial mixture temperature (200 degrees to 615 degrees k). The semitheoretical method of prediction considered are based on three approximate theoretical equations for flame velocity: the Semenov equation, the Tanford-Pease equation, and the Manson equation

An active particle diffusion theory of flame quenching for laminar flames / Dorothy M. Simon and Frank E. Belles

An equation for quenching distance based on the destruction of chain carriers by the surface is derived. The equation expresses the quenching distance in terms of the diffusion coefficients and partial pressures of the chain carriers and gas phase molecules, the efficiency of the surface as a chain breaker, the total pressure of the mixture, and a constant which depends on the geometry of the quenching surface. Quenching distances measured by flashback for propane-air flames are shown to be consistent with the mechanism. The derived equation is used with the lean inflammability limit and a rate constant calculated from burning velocity data to estimate quenching distances for propane-air (hydrocarbon lean) flames satisfactorily

Variation of the pressure limits of flame propagation with tube diameter for propane-air mixtures

An investigation was made of the variation of the pressure limits of flame propagation with tube diameter for quiescent propane with tube diameter for quiescent propane-air mixtures. Pressure limits were measured in glass tubes of six different inside diameters, with a precise apparatus. Critical diameters for flame propagation were calculated and the effect of pressure was determined. The critical diameters depended on the pressure to the -0.97 power for stoichiometric mixtures. The pressure dependence decreased with decreasing propane concentration. Critical diameters were related to quenching distance, flame speeds, and minimum ignition energy

NACA Research Memorandums

Report presenting some laminar-flame-velocity data surveyed with respect to the correspondence between experimental flame velocities and values predicted by semitheoretical and empirical methods

Pilot testing the feasibility of a game intervention aimed at improving help seeking and coping among sexual and gender minority youth: protocol for a randomized controlled trial

Background: Sexual and gender minority youth (SGMY; e.g., lesbian, gay, bisexual, and transgender youth) experience myriad substance use and mental health disparities compared with their cisgender (non-transgender) heterosexual peers. Despite much research showing these disparities are driven by experiences of bullying and cyberbullying victimization, few interventions have aimed to improve the health of bullied SGMY. One possible way to improve the health of bullied SGMY is via an online-accessible game intervention. Nevertheless, little research has examined the feasibility of using an online-accessible game intervention with SGMY. Objectives: To describe the protocol for a randomized controlled trial (RCT) pilot testing the feasibility and limited-efficacy of a game-based intervention for increasing help-seeking-related knowledge, intentions, self-efficacy, and behaviors, productive coping skills use, and coping flexibility, and reducing health risk factors and behaviors among SGMY. Methods: We enrolled 240 SGMY aged 14-18 years residing in the United States into a two-arm prospective RCT. The intervention is a theory-based, community-informed, computer-based, role playing game with three primary components: (1) encouraging help-seeking behaviors; (2) encouraging use of productive coping; and (3) raising awareness of online resources. SGMY randomized to both the intervention and control conditions will receive a list of SGMY-inclusive resources covering a variety of health-related topics. Control condition participants received only the list of resources. Notably, all study procedures are conducted online. We conveniently sampled SGMY using online website advertisements. Study assessments occur at enrollment, 1 month after enrollment, and 2 months after enrollment. The primary outcomes of this feasibility study include implementation procedures, game demand, and game acceptability. Secondary outcomes include help-seeking intentions, self-efficacy, and behaviors; productive coping strategies and coping flexibility; and knowledge and use of online resources. Tertiary outcomes include bullying and cyberbullying victimization; loneliness; mental health issues; substance use; and internalized sexual and gender minority stigma. Results: From April through July 2018, 240 participants were enrolled and randomized. Half of the enrolled participants (n=120) were randomized into the intervention condition, and half (n=120) into the control condition. At baseline, 52% of participants identified as gay or lesbian, 27% as bisexual, 24% as queer, and 12% as another non-heterosexual identity. Nearly half (47%) of participants were a gender minority, 37% were cisgender boys, and 16% were cisgender girls. There were no differences in demographic characteristics between intervention and control condition participants. Data collection is anticipated to end in November 2018. Conclusions: Online-accessible game interventions overcome common impediments of face-to-face interventions and present a unique opportunity to reach SGMY and improve their health. This trial will provide data on feasibility and limited-efficacy that can inform future online studies and a larger RCT aimed at improving health equity for SGMY. Trial Registration: ClinicalTrials.gov NCT03501264; https://clinicaltrials.gov/ct2/show/NCT03501264 (Archived by WebCite at http://www.webcitation.org/72HpafarW

Linked randomised controlled trials of face-to-face and electronic brief intervention methods to prevent alcohol related harm in young people aged 14–17 years presenting to Emergency Departments (SIPS junior)

Background: Alcohol is a major global threat to public health. Although the main burden of chronic alcohol-related disease is in adults, its foundations often lie in adolescence. Alcohol consumption and related harm increase steeply from the age of 12 until 20 years. Several trials focusing upon young people have reported significant positive effects of brief interventions on a range of alcohol consumption outcomes. A recent review of reviews also suggests that electronic brief interventions (eBIs) using internet and smartphone technologies may markedly reduce alcohol consumption compared with minimal or no intervention controls. Interventions that target non-drinking youth are known to delay the onset of drinking behaviours. Web based alcohol interventions for adolescents also demonstrate significantly greater reductions in consumption and harm among ‘high-risk’ drinkers; however changes in risk status at follow-up for non-drinkers or low-risk drinkers have not been assessed in controlled trials of brief alcohol interventions

Pleasure and meaningful discourse: an overview of research issues

The concept of pleasure has emerged as a multi-faceted social and cultural phenomenon in studies of media audiences since the 1980s. In these studies different forms of pleasure have been identified as explaining audience activity and commitment. In the diverse studies pleasure has emerged as a multi-faceted social and cultural concept that needs to be contextualized carefully. Genre and genre variations, class, gender, (sub-)cultural identity and generation all seem to be instrumental in determining the kind and variety of pleasures experienced in the act of viewing. This body of research has undoubtedly contributed to a better understanding of the complexity of audience activities, but it is exactly the diversity of the concept that is puzzling and poses a challenge to its further use. If pleasure is maintained as a key concept in audience analysis that holds much explanatory power, it needs a stronger theoretical foundation. The article maps the ways in which the concept of pleasure has been used by cultural theorists, who have paved the way for its application in reception analysis, and it goes on to explore the ways in which the concept has been used in empirical studies. Central to our discussion is the division between the ‘public knowledge’ and the ‘popular culture’ projects in reception analysis which, we argue, have major implications for the way in which pleasure has come to be understood as divorced from politics, power and ideology. Finally, we suggest ways of bridging the gap between these two projects in an effort to link pleasure to the concepts of hegemony and ideology