An Improved Model of Cryogenic Propellant Stratification in a Rotating, Reduced Gravity Environment

This paper builds on a series of analytical literature models used to predict thermal stratification within rocket propellant tanks. The primary contribution to the literature is to add the effect of tank rotation and to demonstrate the influence of rotation on stratification times and temperatures. This work also looks levels of thermal stratification for generic propellant tanks (cylindrical shapes) over a parametric range of upper-stage coast times, heating levels, rotation rates, and gravity levels

You Can Quit Me But I’m Not Going to Quit You:” A Focus Group Study of Leaders’ Perceptions of Their Positive Influences on Youth in Boy Scouts of America

As part of a longitudinal, mixed-method study with Boy Scouts of America, we conducted five focus groups with a diverse group of 46 program leaders in order to better understand their perceptions of how they influence youth. Drawing from grounded theory analysis methods, we found that leaders believed they promoted positive youth outcomes, including character and self-confidence, through caring youth-leader relationships and facilitating opportunities for youth to participate in and lead skill-building activities and apply skills in different contexts. Leaders differed in the particular outcomes that they emphasized. Implications of these findings for future research and practice are discussed

The Effect of an Isogrid on Cryogenic Propellant Behavior and Thermal Stratification

All models for thermal stratification available in the presentation are derived using smooth, flat plate laminar and turbulent boundary layer models. This study examines the effect of isogrid (roughness elements) on the surface of internal tank walls to mimic the effects of weight-saving isogrid, which is located on the inside of many rocket propellant tanks. Computational Fluid Dynamics (CFD) is used to study the momentum and thermal boundary layer thickness for free convection flows over a wall with generic roughness elements. This presentation makes no mention of actual isogrid sizes or of any specific tank geometry. The magnitude of thermal stratification is compared for smooth and isogrid-lined walls

Phylogeny of Cyperaceae Based on DNA Sequence Data–a New rbcL Analysis

Since the Monocots II meeting in 1998, significant new data have been published that enhance our systematic knowledge of Cyperaceae. Phylogenetic studies in the family have also progressed steadily. For this study, a parsimony analysis was carried out using all rbcL sequences currently available for Cyperaceae, including data for two new genera. One of the four subfamilies (Caricoideae) and seven of the 14 tribes (Bisboeckelereae, Cariceae, Cryptangieae, Dulichieae, Eleocharideae, Sclerieae, Trilepideae) are monophyletic. Subfamily Mapanioideae and tribe Chrysitricheae are monophyletic if, as the evidence suggests, Hellmuthia is considered a member of Cypereae. Some other features of our analysis include: well-supported Trilepideae and Sclerieae–Bisboeckelereae clades; a possible close relationship between Cryptangieae and Schoeneae; polyphyletic tribes Schoeneae and Scirpeae; the occurrence of Cariceae within the Dulichieae–Scirpeae clade, and a strongly supported clade, representing Cyperus and allied genera in Cypereae, sister to a poorly supported Ficinia–Hellmuthia– Isolepis–Scirpoides clade. Such patterns are consistent with other studies based on DNA sequence data. One outcome may be that only two subfamilies, Mapanioideae and Cyperoideae, are recognized. Much further work is needed, with efforts carefully coordinated among researchers. The work should focus on obtaining morphological and molecular data for all genera in the family

Experimental and theoretical studies of the reaction of atomic oxygen with silane

Article on experimental and theoretical studies of the reaction of atomic oxygen with silane

Systematic review of communication technologies to promote access and engagement of young people with diabetes into healthcare

Background: Research has investigated whether communication technologies (e.g. mobile telephony, forums, email) can be used to transfer digital information between healthcare professionals and young people who live with diabetes. The systematic review evaluates the effectiveness and impact of these technologies on communication. Methods: Nine electronic databases were searched. Technologies were described and a narrative synthesis of all studies was undertaken. Results: Of 20,925 publications identified, 19 met the inclusion criteria, with 18 technologies assessed. Five categories of communication technologies were identified: video-and tele-conferencing (n = 2); mobile telephony (n = 3); telephone support (n = 3); novel electronic communication devices for transferring clinical information (n = 10); and web-based discussion boards (n = 1). Ten studies showed a positive improvement in HbA1c following the intervention with four studies reporting detrimental increases in HbA1c levels. In fifteen studies communication technologies increased the frequency of contact between patient and healthcare professional. Findings were inconsistent of an association between improvements in HbA1c and increased contact. Limited evidence was available concerning behavioural and care coordination outcomes, although improvement in quality of life, patientcaregiver interaction, self-care and metabolic transmission were reported for some communication technologies. Conclusions: The breadth of study design and types of technologies reported make the magnitude of benefit and their effects on health difficult to determine. While communication technologies may increase the frequency of contact between patient and health care professional, it remains unclear whether this results in improved outcomes and is often the basis of the intervention itself. Further research is needed to explore the effectiveness and cost effectiveness of increasing the use of communication technologies between young people and healthcare professionals

On a Pathway Towards Thriving: Evaluating the Effectiveness of Tools to Promote Positive Development and Intentional Self Regulation in Youth

This article provides initial data about the reliability and validity of tools aimed at promoting youth intentional self regulation (ISR) within mentoring programs. Based on the translation of the theory-based research about ISR and youth thriving conducted within the 4-H Study of Positive Youth Development (PYD), the GPS to Success tools use the metaphor of a car’s GPS navigational system to enhance goal-directed behaviors among youth. The core GPS tools are “growth grids,” designed to help mentors appraise ISR skill development and to link these skills to other grids assessing the Five Cs of PYD and Contribution. Data from 152 mentor and youth pairs from 4-H program sites in Oregon and North Carolina indicated that the growth grids were generally reliable. Although validity evidence was mixed, rubrics for “G” and “P” and for a global GPS score were related to a well-validated measure of ISR

On a Pathway Towards Thriving: Evaluating the Effectiveness of Tools to Promote Positive Development and Intentional Self Regulation in Youth

This article provides initial data about the reliability and validity of tools aimed at promoting youth intentional self regulation (ISR) within mentoring programs. Based on the translation of the theory-based research about ISR and youth thriving conducted within the 4-H Study of Positive Youth Development (PYD), the GPS to Success tools use the metaphor of a car’s GPS navigational system to enhance goal-directed behaviors among youth. The core GPS tools are “growth grids,” designed to help mentors appraise ISR skill development and to link these skills to other grids assessing the Five Cs of PYD and Contribution. Data from 152 mentor and youth pairs from 4-H program sites in Oregon and North Carolina indicated that the growth grids were generally reliable. Although validity evidence was mixed, rubrics for “G” and “P” and for a global GPS score were related to a well-validated measure of ISR