Involute composite design evaluation using global design sensitivity derivatives

An optimization capability for involute structures has been developed. Its key feature is the use of global material geometry variables which are so chosen that all combinations of design variables within a set of lower and upper bounds correspond to manufacturable designs. A further advantage of global variables is that their number does not increase with increasing mesh density. The accuracy of the sensitivity derivatives has been verified both through finite difference tests and through the successful use of the derivatives by an optimizer. The state of the art in composite design today is still marked by point design algorithms linked together using ad hoc methods not directly related to a manufacturing procedure. The global design sensitivity approach presented here for involutes can be applied to filament wound shells and other composite constructions using material form features peculiar to each construction. The present involute optimization technology is being applied to the Space Shuttle SRM nozzle boot ring redesigns by PDA Engineering

Levels of Information Processing in a Fitts law task (LIPFitts)

State-of-the-art flight technology has restructured the task of human operators, decreasing the need for physical and sensory resources, and increasing the quantity of cognitive effort required, changing it qualitatively. Recent technological advances have the most potential for impacting a pilot in two areas: performance and mental workload. In an environment in which timing is critical, additional cognitive processing can cause performance decrements, and increase a pilot's perception of the mental workload involved. The effects of stimulus processing demands on motor response performance and subjective mental workload are examined, using different combinations of response selection and target acquisition tasks. The information processing demands of the response selection were varied (e.g., Sternberg memory set tasks, math equations, pattern matching), as was the difficulty of the response execution. Response latency as well as subjective workload ratings varied in accordance with the cognitive complexity of the task. Movement times varied according to the difficulty of the response execution task. Implications in terms of real-world flight situations are discussed

The use of podcasts and videocasts by tertiary accounting students in distance education

Podcasts and videocasts are increasingly used in education, as they provide additional flexible learning resources to students. Research on the educational use and design of videocasts used by students in a distance education environment is, however, limited. In light of the need to ascertain how best to design videocasts, this article reports on distance students’ perceptions of using this technological innovation as part of teaching support provided by educators. The research was conducted by means of a survey and it investigated how videocasts were used by undergraduate students in a taxation module. The research also investigated the usefulness of videocasts to students in mastering the extensive content and complex principles. The results from this study found that students generally access the videocasts from home on a computer/laptop while working through or after reading the study unit. Most students reject the mobile aspect of videocasting and prefer to maintain their traditional study habits by watching each videocast at least once (or more than once for more difficult topics) during their focused study time. The majority of students perceive videocasting as having value, as this initiative provides them with additional support and helps them to understand the content more easily. It is evident that the use of videocasts as an additional learning tool in taxation distance education courses can enhance the learning experience of accounting students and it is a viable way of communicating content to and documenting processes for students to enable them to study more effectively

“If You Are Old Enough to Die for Your Country, You Should Be Able to Get a Pinch of Snuff”: Views of Tobacco 21 Among Appalachian Youth

Background: Multiple strategies have been utilized in attempts to decrease the prevalence of youth tobacco use. One strategy, raising the minimum legal sale age (MLSA) of tobacco products to 21, known as Tobacco 21, has recently gained popularity. Tobacco 21 legislation targets youth tobacco use by obstructing two main sources of youth tobacco products: stores and older friends. Although these sources are the most common for youth across the nation, regional differences have not been explored. Further, youth perspectives about raising the tobacco MLSA have not been considered. Youth may help identify potential challenges to implementing tobacco control measures, as well as suggest alternatives for intervention, thus helping to shape successful tobacco control policies. Study Aim: This study aimed to 1) examine youth perspectives on raising the tobacco minimum legal sale age to 21 and 2) identify common sources of tobacco products among middle and high school students living in rural, low-income Appalachian communities. Methods: A cross-sectional survey about perceptions and use of tobacco products was conducted with students in the Appalachian regions of Kentucky and North Carolina (N=426). Questions were asked concerning perspectives on the effect of Tobacco 21 implementation. Descriptive statistics characterized participants by Tobacco 21 perspectives. Participants were given the opportunity to further expand upon their opinions in an open-ended format. Results: The majority (58.7%) of participants responded that the same number of youth would use tobacco if the legal purchase age were raised, followed by responses that fewer would use (28.9%) and more would use (12.4%). Significant differences emerged based on tobacco use status (p\u3c.05), friends’ tobacco use (p\u3c.001), and whether participants identified family members as sources of youth tobacco products (p=.047). When given the opportunity to expand upon their views concerning the implementation of Tobacco 21 laws in their communities, many respondents cited poor enforcement of tobacco MLSAs at stores, continued access to tobacco products from family members and friends, and the overall abundance of tobacco in their communities as potential barriers to the successful implementation. Conclusion: Fewer than one-third of participants believed that Tobacco 21 legislation would succeed in reducing the prevalence of youth tobacco use. Perspectives on the effect of Tobacco 21 legislation were related to personal tobacco use, exposure to tobacco users, and beliefs that family members provide tobacco products to youth. Open-ended responses identify potential obstacles in implementing Tobacco 21 legislation in Appalachia. Future research should attempt to include youth perspectives when designing and implementing tobacco control policies and examine family members as sources of tobacco products for youth

The monopole mass in the three-dimensional Georgi-Glashow model

We study the three-dimensional Georgi-Glashow model to demonstrate how magnetic monopoles can be studied fully non-perturbatively in lattice Monte Carlo simulations, without any assumptions about the smoothness of the field configurations. We examine the apparent contradiction between the conjectured analytic connection of the `broken' and `symmetric' phases, and the interpretation of the mass (i.e., the free energy) of the fully quantised 't Hooft-Polyakov monopole as an order parameter to distinguish the phases. We use Monte Carlo simulations to measure the monopole free energy and its first derivative with respect to the scalar mass. On small volumes we compare this to semi-classical predictions for the monopole. On large volumes we show that the free energy is screened to zero, signalling the formation of a confining monopole condensate. This screening does not allow the monopole mass to be interpreted as an order parameter, resolving the paradox.Comment: 12 pages, 7 figures, uses revtex. Minor changes made to the text to match with the published version at http://link.aps.org/abstract/PRD/v65/e12500

The potential therapeutic effects of creatine supplementation on body composition and muscle function in cancer

Low muscle mass in individuals with cancer has a profound impact on quality of life and independence and is associated with greater treatment toxicity and poorer prognosis. Exercise interventions are regularly being investigated as a means to ameliorate treatment-related adverse effects, and nutritional/supplementation strategies to augment adaptations to exercise are highly valuable. Creatine (Cr) is a naturally-occurring substance in the human body that plays a critical role in energy provision during muscle contraction. Given the beneficial effects of Cr supplementation on lean body mass, strength, and physical function in a variety of clinical populations, there is therapeutic potential in individuals with cancer at heightened risk for muscle loss. Here, we provide an overview of Cr physiology, summarize the evidence on the use of Cr supplementation in various aging/clinical populations, explore mechanisms of action, and provide perspectives on the potential therapeutic role of Cr in the exercise oncology setting

TRIAD - Preliminary design of an operational earth resources survey system. 1969 summer faculty fellowship program in engineering systems design

TRIAD, preliminary design of operational earth resources survey syste

Detailed two-dimensional modelling of a complex bridge arrangement – McKinlay River No. 2 Bridge, Alice Springs to Darwin railway

The Alice Springs – Darwin Railway Project involved the construction of 1420 km of new standard gauge track between Alice Springs and Darwin, including the McKinlay River No. 2 Bridge. During the 2006, 2007 and 2008 flood seasons, significant scour occurred around the McKinlay River No. 2 Bridge piers, raising concerns regarding the continuing stability of the structure. The site has complex geometry, with the river approaching the crossing at a significant angle and the remains of the original railway bridge just upstream of the new structure. Owing to the complex arrangement, a detailed 2-D hydrodynamic SOBEK model of the bridge crossing was developed to inform the design of scour protection works at the site. The model was used to analyse a number of options to reduce the potential for scour, and allowed for the scour protection works to be optimised for conditions at the site. The designed protection works were constructed in 2011, and have performed well in several subsequent flow events