Describing the plastic deformation of aluminium softball bats

Hollow aluminium bats were introduced over 30 years ago to provide improved durability over wooden bats. Since their introduction, however, interest in hollow bats has focused almost exclusively around their hitting performance. The aim of this study was to take advantage of the progress that has been made in predicting bat performance using finite elements and apply it to describe bat durability. Accordingly, the plastic deformation from a ball impact of a single-wall aluminum bat was numerically modelled. The bat deformation from the finite-element analysis was then compared with experiment using a high-speed bat test machine. The ball was modelled as an isotropic, homogeneous, viscoelastic sphere. The viscoelastic parameters of the ball model were found from instrumented, high-speed, rigid-wall ball impacts. The rigid-wall ball impacts were modelled numerically and showed good agreement with the experimentally obtained response. The strain response of the combined bat-ball model was verified with a strain-gauged bat at intermediate ball impact speeds in the elastic range. The strain response of the bat-ball model exhibited positive correlation with the experimental measurements. High-speed bat-ball impacts were performed experimentally and simulated numerically at increasing impact speeds which induced correspondingly increased dent sizes in the bat. The plastic deformation from the numerical model found good agreement with experiment provided the aluminium work hardening and strain rate effects were appropriately described. The inclusion of strain rate effects was shown to have a significant effect on the bat deformations produced in the finite-element simulations. They also helped explain the existence of high bat stresses found in many performance models.     

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3月3～6日，On Demand展览会暨研讨会在美国波土顿举行。组织者称其为世界领先的数码印刷展会和研讨会。我们将以对话的形式带您一起回顾。     

'It was Better than Sitting in a Group and Talking'. An Evaluation of a Film-Making Project with Young People in Trouble or 'At Risk' in School

This paper will explore some issues raised by an evaluation of a Scottish video making project which works with young people in trouble or 'at risk' in school. In the paper we reflect on the problems of evaluating work with troubled and troublesome pupils and on the difficulties of both collecting and presenting appropriate evidence. It offers a contribution to continuing debates over educational exclusion and inclusion and to the research literature on strategies for supporting young people in school. The paper also raises key questions about the planning and evaluating of support services for young people by schools.     

Interactive Kiosk at the Texas Tech University Libraries

The academic library, given its often privileged position on campus, is the information source that can include directional as well as general campus facts among the myriad of print and e-resources for reference. Also, an academic library's audiences can be quite varied and include prospective students or parents seeking more general knowledge of the building and the campus. Many times this need for information drives patrons to the library service desks. Sometimes, especially during the high-demand seasons of new student orientation and beginning of the fall semesters, the desk is so busy that many patrons will leave because they don't have the time to wait. To address this immediate need for information, Texas Tech University Libraries developed an interactive kiosk to provide general information for frequently asked questions in a more efficient, creative, and interactive way. The kiosk provides a fun method of satisfying a patron's information needs without the requirement of a staff member or the need to wait in line for help. The kiosk is available as long as the Library is open and provides a variety of useful answers to general questions, as well as facts about the Library.     

Interactions between Niche and Regime: An Analysis of Learning and Innovation Networks for Sustainable Agriculture across Europe

Abstract

Purpose: This paper aims to reveal, and contribute to an understanding of, the processes that connect learning and innovation networks in sustainable agriculture to elements of the mainstream agricultural regime. Drawing on the innovations and transition literature, the paper frames the analysis around niche-regime interaction using the notion of niche-regime compatibility.

Design/Methodology/Approach: 17 Learning and Innovation Networks for Sustainable Agriculture (LINSA) engaged in agricultural food production, non-food and rural development were analyzed. In line with the project's transdisciplinary approach data were collected in a series of participatory workshops.

Findings: Five modes of LINSA-regime interaction are distinguished based on compatibility. The level of LINSA-regime compatibility influences the extent of the diffusion of LINSA ideas and practices into the regime. However, interaction processes within these modes reveal multiple and diverse connections between LINSA and regime entities suggesting a more complex relationship exists.

Practical implications: A range of connecting processes and activities (for example, certification, exemption from regulation, facilitation of networking) can bring about effective LINSA-regime interaction and could be externally supported.

Originality/Value: Empirical evidence from 17 case studies provides valuable insights from a number of different contexts across Europe. By directing analysis of interaction at the level of LINSA (niche project), rather than at the macro level, the study offers an original perspective. It suggests that the transition to sustainable agriculture might be understood as a complex of interactive processes leading to a series of adaptive changes, rather than as regime change.     

Is more child-initiated always better? Exploring relations between child-initiated instruction and preschoolers’ school readiness

Although research suggests that the use of child-initiated vs. teacher-directed instructional practices in early childhood education has implications for learning and development, the precise nature of these effects remains unclear. Using data from the Midwest Child-Parent Center (CPC) Expansion Project, the present study examined the possibility that a blend of child- and teacher-directed practices best promotes school readiness among preschoolers experiencing high levels of sociodemographic risk and explored whether the optimal blend varies based on child characteristics. Sixty-two CPC preschool teachers reported their instructional practices throughout the year, using a newly developed questionnaire—the Classroom Activity Report (CAR). The average reported proportion of child-initiated instruction was examined in relation to students’ end-of-year performance on a routine school readiness assessment (N = 1289). Although there was no main effect of child-initiated instruction on school readiness, there was a significant interaction between instruction and student age. Four-year-olds’ school readiness generally improved as the proportion of child-initiated time increased, while 3-year-olds showed a U-shaped pattern. The present findings add to the evidence that child-initiated instruction might support preschoolers’ school readiness, although they also suggest this relation may not always be linear. They also point to the importance of examining instructional strategies in relation to student characteristics, in order to tailor strategies to the student population. The CAR has potential as a brief, practical measurement tool that can support program monitoring and professional development.

     

Field and laboratory measurements of softball player swing speed and bat performance

The swing speed of the bat is one of the most important factors affecting the hit-ball speed. Most field studies tend to focus on measuring ball speed, which is easier to measure and quantify than bat speed. For this reason, relatively little data exist describing bat motion in field conditions. The following describes a relatively large swing speed field study involving bats of the same model with nearly constant weight and varying inertia. The study was conducted using right-handed batters on a regulation outdoor field with a live pitcher. Swing speed was measured by tracking markers on the bat with two high-speed video cameras so that the bat markers could be traced in three-dimensional space. The ball motion was tracked using the same high-speed video cameras and a three-dimensional Doppler radar system. Bat swing speed was observed to be proportional to the batter skill level and the normalised swing speed increased with decreasing bat inertia. The bat centre of rotation during impact was close to the knob of the bat. The bats were tested under controlled laboratory conditions using a standardised performance test. The field and laboratory results showed good agreement including the hit-ball speed and the subtle effect of bat inertia on the maximum performance location. The vibrational response of the bats was considered using modal analysis. The maximum performance location was correlated with the node of the first vibrational mode.     

Vocabulary does not complicate the simple view of reading

Gough and Tunmer’s (1986) simple view of reading (SVR) proposed that reading comprehension (RC) is a function of language comprehension (LC) and word recognition/decoding. Braze et al. (2007) presented data suggesting an extension of the SVR in which knowledge of vocabulary (V) affected RC over and above the effects of LC. Tunmer and Chapman (2012) found a similar independent contribution of V to RC when the data were analyzed by hierarchical regression. However, additional analysis by factor analysis and structural equation modeling indicated that the effect of V on RC was, in fact, completely captured by LC itself and there was no need to posit a separate direct effect of V on RC. In the present study, we present new data from young adults with sub-optimal reading skill (N = 286). Latent variable and regression analyses support Gough and Tunmer’s original proposal and the conclusions of Tunmer and Chapman that V can be considered a component of LC and not an independent contributor to RC.     

Preschoolers modulate contrastive inferences during online language comprehension

This study examined 4- and 5-year-olds' incremental interpretation of size adjectives, focusing on whether contrastive inferences are modulated by speaker behavior. Children (N = 120, 59 females, mostly White, tested between July, 2018 and August, 2019) encountered either a conventional or unconventional speaker who labeled objects in a correspondingly typical or atypical way. Critical utterances contained size adjectives (e.g., “Look at the big duck”). With conventional speakers, gaze measures indicated that children rapidly used the adjective to differentiate members of a contrasting pair, indicating that even 4-year-olds derive contrastive inferences. With unconventional speakers, contrastive inferences were delayed in processing. The findings demonstrate that preschoolers adjust their use of pragmatic cues when presented with evidence disconfirming their default assumptions about a speaker.