Characterization of bubbly and slug flow regimes generated in a minichannel in microgravity conditions

We performed a characterization of the bubbly and slug flow regimes in minichannels in conditions relevant to microgravity. Two-phase flows were generated on ground by means of a T-junction device (1 mm i.d.), whose operation is independent to changes in gravity level [1]. Air and water were injected at several superficial velocities ranging from 0 up to 2 m/s. The generation and detachment of the minibubbles is provided by the liquid cross-flow (see figure). In nominal conditions small Bond and Weber numbers are achieved for the air/water mixture flow. Therefore, capillary forces dominate over buoyancy and inertial forces [2]. Laminar regime can also be assumed. Bubbly, slug, churn and annular flows were observed (see figure). The characterization consists in the analysis of the bubble and the unit cell lengths, the bubble velocity and the void fraction in both bubbly and slug flow regimes.Peer Reviewe

Bubble and slug flows characteristic lengths in a microchannel

Peer ReviewedPostprint (published version

Comparison of two methods for generating small bubbles with a T-junction in microgravity conditions

Peer ReviewedPostprint (published version

The Protection Motivation Theory as a Predictor of the Use of Protective Behavioral Strategies among Young Adults

Alcohol Protective Behavioral Strategies (PBS) have shown to be effective in minimizing alcohol-related negative consequences. However, previous studies on the explanatory factors of PBS use are scarce. The Protection Motivation Theory (PMT) is a social cognition theory which attempts to explain intention to use protective behaviors in respond to health threats such as alcohol-related negative consequences. According to PMT, the likelihood of engaging in protective behaviors when facing a threat is a product of two processes: threat appraisal (perceived severity and perceived vulnerability to the threat) and coping appraisal (response efficacy and perceived self-efficacy for using a protective behavior). We examined the predictive utility of the PMT on the intention to use PBS related to the Manner of Drinking (MOD) among a community sample of young adults. Prospective study that recruited 360 young adults aged 18-24 years by targeted sampling procedure (Mage=21.15 [SD=2.23]; female=50.3%). Most baseline participants (94.2%, n=339) completed a 2-months follow-up assessment. Perceived severity and perceived vulnerability to alcohol use, perceived efficacy of MOD strategies to reduce alcohol-related negative consequences, and self-efficacy to engage in MOD strategies were measured at baseline, and intention to use MOD strategies at follow-up. A multiple lineal regression model for predicting intention to use MOD strategies was used. Perceived severity (β=.13, p=.017), response efficacy (β=.270, p<.001), and selfefficacy (β=.240, p<.000) were positively associated with high intention to use MOD protective strategies. In line with previous research, our findings demonstrated that coping-appraisal components of PMT are more explanatory of protective behaviors than threat-appraisal components. These results may be useful to inform interventions aimed at increasing PBS use among young adults.Fil: González Ponce, Bella. Universidad de Huelva; EspañaFil: Carmona Márquez, José. Universidad de Huelva; EspañaFil: Vera, Belén del Valle. Universidad Nacional de Córdoba. Instituto de Investigaciones Psicológicas. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Psicológicas; ArgentinaFil: Pautassi, Ricardo Marcos. Universidad Nacional de Córdoba. Facultad de Psicología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Fernández Calderón, Fermín. Universidad de Huelva; España17th European Congress of PsychologyLiublianaEslovenialovenian Psychologists’ Associatio

Microbubble injector: an experimental quantitative characterization

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Characterization of the performance of an injector for the controlled generation of microbubbles

We perform a characterization of a recently reported microbubble injector in conditions relevant to microgravity. Injection of bubbles is based on the generation of a slug flow in a capillary T-junction, whose operation is robust to changes in the gravity level. We address questions regarding the performance under different working regimes. In particular, we focus on the regimes found within a large range of gas and liquid injection flow rates. The injection performance is characterized by measuring bubble generation frequency. We propose curves obtained empirically for the behavior of generation frequency and crossover between regimes.Peer Reviewe

Characterization of the performance of an injector for the generation of controlled microbubbles

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Characterization of a microbubble injector for applications in microgravity

Peer Reviewe