14 research outputs found

    On the analysis of the contact angle for impacting droplets using a polynomial fitting approach

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    ractical considerations on the measurement of the dynamic contact angle and the spreading diameter of impacting droplets are discussed in this paper. The contact angle of a liquid is commonly obtained either by a polynomial or a linear fitting to the droplet profile around the triple phase point. Previous works have focused on quasi-static or sessile droplets, or in cases where inertia does not play a major role on the contact angle dynamics. Here, we study the effect of droplet shape, the order of the fitting polynomial, and the fitting domain, on the measurement of the contact angle on various stages following droplet impact where the contact line is moving. Our results, presented in terms of the optical resolution and the droplet size, show that a quadratic fitting provides the most consistent results for a range of various droplet shapes. As expected, our results show that contact angle values are less sensitive to the fitting conditions for the cases where the droplet can be approximated to a spherical cap. Our experimental conditions include impact events with liquid droplets of different sizes and viscosities on various substrates. In addition, validating past works, our results show that the maximum spreading diameter can be parameterised by the Weber number and the rapidly advancing contact angle

    SPEAR: sustainable options for people catchment and aquatic resources

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    This book describes the approach and main result obtained in the Sustainable options for People, Catchment and Aquatic Resources (SPEAR) Project, together with complementary case studies focusing on realted work in China and in the United States. Each chapter in this book is designed to be readable by itself and contains enough information for the reader to understand both the methodologies applied and the key outcomes. Wherever possible, those outcomes have been developed into products, with the objective of leveraging their usability as a legacy of SPEA

    Friendship context matters: Examining the domain specificity of alcohol and depression socialization among adolescents

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    Contains fulltext : 102553.pdf (publisher's version ) (Open Access)Driven by existing socialization theories, this study describes specific friendship contexts in which peer influence of alcohol misuse and depressive symptoms occurs. In the fall and spring of the school year, surveys were administered to 704 Italian adolescents (53 % male, M (age) = 15.53) enrolled in Grades 9, 10 and 11. Different friendship contexts were distinguished based on two dimensions referring to the level (i.e., best friendships and friendship networks) and reciprocity (i.e., unilateral and reciprocal) of the relationships. Social network and dyadic analyses were applied in a complementary manner to estimate peer socialization effects across the different friendship contexts. Results showed that within friendship networks both male and female adolescents' alcohol misuse was affected by friends' alcohol misuse, regardless of whether the relationship was reciprocated or not. Conversely, peer socialization of depressive symptoms only emerged within very best friendship dyads of female adolescents. Findings suggest that the effects of peer socialization depend on the friendship context and specific types of behaviors. The theoretical and methodological implications of the findings are discussed.17 p
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