Braided composite materials for the production of lightweight, high rigidity golf shafts

Braiding is not currently used in the production of golf shafts. The objective of this work was to develop, through a modelling process consisting of altering lamina sequence, a golf shaft, using braided laminas, which would have mass, stiffness and torque comparable to commercially available composite and steel shafts. A 2D conical braided composite model was previously developed and validated to predict elastic constants of braided closed meshed structures. Energy methods were used to calculate the stiffness and torque of shafts using prescribed industry approaches. Shaft mass was calculated based on geometry and density of constitutent materials. Modelled shafts had both braided and unidirectional layers and compared favourably with or were better than commercially available composite and steel shafts in terms of deflection force and twist angle; they had the same weight as composite shafts but were much lighter than steel shafts. If these findings are verified, braided composites would be a viable and effective approach to the design of future golf shafts.     

Multivariate prediction of academic performance by Hong Kong University students

Verbal intelligence, English-language skills, personality, and attitude scales were used as predictors of academic performance in 230 male and female arts students at the University of Hong Kong. A series of bivariate, multiple, and canonical correlation analyses were performed. The results showed that verbal intelligence and attitudes, excepting study orientation, were not predictive of performance. English-language skills had the most predictive value, accounting for about 10% of the variance of performance measures. Personality variables failed to predict performance when composite criterion measures (GPAs) were used; however, they proved to be of predictive value when results of individual academic subjects were used as criterion measures. The study points to the importance of using noncomposite criterion measures in prediction and of considering the cultural context of achievement.     

In Physics Education,Perception Matters

Student difficulties in science learning are frequently attributed to misconceptions about scientific concepts. We argue that domain‐general perceptual processes may also influence students' ability to learn and demonstrate mastery of difficult science concepts. Using the concept of center of gravity (CoG), we show how student difficulty in applying CoG to an object such as a baseball bat can be accounted for, at least in part, by general principles of perception (i.e., not exclusively physics‐based) that make perceiving the CoG of some objects more difficult than others. In particular, it is perceptually difficult to locate the CoG of objects with asymmetric‐extended properties. The basic perceptual features of objects must be taken into account when assessing students' classroom performance and developing effective science, technology, engineering, and mathematics (STEM) teaching methods.     

Partisan Patriotism in the American Presidency: American Exceptionalism,Issue Ownership,and the Age of Trump

This study employs issue ownership theory to examine the partisan dynamics surrounding the idea of American exceptionalism in presidential discourse. We conducted a content analysis of invocations of American exceptionalism in all major U.S. presidential addresses—domestic and foreign—from the end of World War II through Trump’s 1st year in office. We find that even though Republicans have traditionally claimed ownership of American exceptionalism, patterns in presidential discourse tell a very different story. Specifically, our results show (a) in domestic contexts, Republican and Democratic presidents were very similar in their invocations of American exceptionalism during the Cold War but that Democrats have held a substantial advantage over Republicans throughout the post–Cold War era, including on issue areas that Republicans are perceived to “own” (e.g. national security); (b) in foreign contexts, Democrats have been much more outspoken in their embrace of American exceptionalism throughout both the Cold War and post–Cold War; and (c) President Trump has diverged significantly, both in substance and frequency, from his Democratic and Republican predecessors in his invocation of American exceptionalism. We reflect on the implications of these findings on our broader understanding of issue—and trait—ownership, presidential discourse, and American exceptionalism in American politics.     

The Sum Is Greater Than the Parts: Deconstructing Homemade PowerPoint Games

Homemade PowerPoint games are a low-tech alternative for using game design in classrooms. To date, much of the research examining the games has not shown an improvement in performance. This has led some to question whether the games are properly aligned with the instructional strategies researchers have used as justifications to support using them. This study examined how increasing the structure of the game design project affected student performance when compared to control groups, as well as those who created games in previous iterations of the study. In addition, we examined the effects of student performance when two of the instructional strategies (microtheme writing and question writing) were tested in isolation. Most of the comparisons showed no statistical difference in performance; however, results from the final iteration yielded significant gains when compared to the control group.     

Academic workload: the silent barrier to the implementation of technology-enhanced learning strategies in higher education

The effect of technology-enhanced learning (TEL) strategies in higher education has arguably been transformative despite the not-insignificant barriers existing in this context. Throughout the discourse very little attention has been paid to those primarily responsible for this implementation—academic teaching staff. This paper aims to highlight the impact of academic workload allocations, an often silent barrier to the uptake of TEL strategies in higher education. We will discuss the effects of academic identity and culture, preferential time allocation to associative activities, academic technological capacity, university policies and workload and funding models on the uptake, and implementation on TEL in higher education. Our aim is to highlight the risks to staff, students and institutions should these concerns not be addressed and to propose a model for utilisation by all staff responsible for implementing flexible workload models supportive of further implementation of TEL strategies across the sector.     

Reading attitudes in Vietnam: Initial study of the early school years

Whereas cognitive and linguistic factors for learning to read have been extensively studied, less is known about affective factors including children’s attitudes toward reading. Studies primarily from English-speaking and Western countries show gradual declines in reading attitudes in elementary school (McKenna et al., Reading Research Quarterly 30:626–639, 1995) and a positive association between reading attitudes and achievement (Petscher, Journal of Research in Reading 33:335–355, 2010). Children from Asian and African countries are underrepresented in this literature; whether these patterns can be generalized across cultures needs further investigation. This longitudinal study examined the reading attitudes of 84 children in Vietnam from grades 1 to 2 and their relations to reading performance, as measured by translated and adapted versions of the Elementary Reading Attitude Survey and Early Grade Reading Assessment, respectively. This sample from Vietnam showed a small decline in reading attitudes over time, particularly in attitudes toward academic reading. However, children on average reported feeling happy about reading in both grades. Correlations revealed different patterns of association between reading attitudes and performance based on the reading measure employed, grade level, and type of reading in question (academic versus recreational). In grade 2, reading attitudes explained unique variance in reading comprehension even after text fluency and mother’s education were considered. We present a margins plot to visualize the role of reading attitudes on reading comprehension. We discuss educational implications and future directions.

     

An improvement on the transient response of tracking for the sampled-data system based on an improved PD-type iterative learning control

An improvement on the transient response of tracking for the sampled-data system based on an improved PD-type iterative learning control (ILC) is proposed in this paper. The developed analog ILC method and the high-gain property tracker design methodology are first combined to significantly reduce learning epochs and overcome the initial condition shift problem and discontinuous reference input in the traditional ILC. Besides, the proposed ILC improves the transient response and decreases the rate of weighting matrices Q$Q$ to R$R$ under the traditional linear quadratic tracker design. First, the off-line observer/Kalman filter identification (OKID) is used to determine the appropriate (low-) order system parameters and state estimator for the physical system with unknown system equation, so that the model-based PD-type ILC can be implemented for practical applications. Then, to improve the transient response and decrease the control effort, the proportional difference type (PD-type) ILC algorithm is combined with the high-gain property linear quadratic tracker (LQT) design to construct the high performance tracker for the model-based sampled-data systems. Furthermore, the discrete-time version high performance tracker design for the unknown stochastic sampled-data system via the iterative learning control method is proposed in this paper based on the Euler method and the digital redesign approach. Finally, some examples are given for illustrating the effectiveness of the proposed method.     

Programmed sample delivery on a pressurized paper

This paper reports a method to control the fluid flow in paper-based microfluidic devices simply by pressing over the channel surface of paper, thereby decreasing the pore size and permeability of a non-woven polypropylene sheet. As a result, fluid resistance is increased in the pressed region and causes flow rate to decrease. We characterize the decrease of flow rate with respect to different amounts of pressure applied, and up to 740% decrease in flow velocity was achieved. In addition, we demonstrate flow rate control in a Y-shaped merging paper and sequential delivery of multiple color dyes in a three-branched paper. Furthermore, sequential delivery of multiple fluid samples is performed to demonstrate its application in multi-step colorimetric immunoassay, which shows a 4.3-fold signal increase via enhancement step.