Thermal optimization of a totally enclosed forced ventilated permanentmagnet traction motor using lumped parameter and partial computational fluid dynamics modeling

In this study, we present a thermal optimization method using the overall lumped parameter (LP) and partial computational fluid dynamics (CFD) modeling for a 600-kW permanent magnet traction motor developed for high-speed trains. The motor is totally enclosed forced ventilated to achieve high power density, high efficiency, and low maintenance requirements. Considering the electro-magnetic performance, bogie space, and thermal capacity, we propose a ventilation structure with zigzag plates in sector cross-section. We focus particularly on the ventilation channels and propose an overall LP model for thermal optimization, in which the full consideration of the influence of turbulent flow is given by using a partial CFD model. Given the specific critical parameters from the optimization results, we present a complete 3D CFD model of the whole motor to obtain an accurate temperature distribution and the maximum temperature rises in local points. The benefit of zigzag plates is studied extensively using both the LP and the complete CFD models and the results are verified by equivalent thermal experiments under rated operations. Experimental results indicate that the ventilation structure fulfills the normal operational demands of high-speed trains by improving thermal performance by more than 15%. Additionally, we propose an engineering method to estimate iron loss constraint with the complete CFD model to guide the control system design.     

What do students believe about effective classroom management? A mixed-methods investigation in Western Australian high schools

Students’ views about teaching, learning, and school experiences are important considerations in education. The purpose of this study was to examine students’ perceptions of teachers who create and maintain safe and supportive learning environments. To achieve this, a survey was conducted with 360 students to capture students’ views on their classroom experiences. Follow-up focus group discussions were used to further elaborate and clarify students’ perceptions. Despite varying school contexts, students provided consistent reports that effective classroom managers meet students’ needs by developing caring relationships and controlling the classroom environment while developing student responsibility and engaging students in their learning.     

Different People in Different Places

This article presents the results of an exploratory study of students’ knowledge about scientists and countries’ contributions to science, aiming at answering two research questions: “In which ways are students aware of the history of scientific development carried out by different people in different places of the world? What can be influencing and shaping their awareness?” Thus, this study aimed at depicting students’ knowledge about History of Science (HOS), focusing on what they know about science being done by people and communities from different parts of the world and on how this knowledge is constructed through their engagement with school science. An exploratory research was carried out at two multicultural state secondary schools in London, UK, involving 200 students aged 12–15 (58.5% girls, 41.5% boys) and five science teachers. The method involved an initial exploration of students’ knowledge about HOS through an open-ended survey, followed by classroom-based observations and semi-structured interviews with the participants. Results showed a disconnection between remembering scientists and knowing about their work and background, hinting at an emphasis on illustrative and decontextualised approaches towards HOS. Additionally, there was a lack of diversity in these students’ answers in terms of gender and ethnicity when talking about scientists and countries in science. These findings were further analysed in relation to their implications for school science and for the fields of HOS, science education and public perception of science.     

Statistical learning of action: The role of conditional probability

Identification of distinct units within a continuous flow of human action is fundamental to action processing. Such segmentation may rest in part on statistical learning. In a series of four experiments, we examined what types of statistics people can use to segment a continuous stream involving many brief, goal-directed action elements. The results of Experiment 1 showed no evidence for sensitivity to conditional probability, whereas Experiment 2 displayed learning based on joint probability. In Experiment 3, we demonstrated that additional exposure to the input failed to engender sensitivity to conditional probability. However, the results of Experiment 4 showed that a subset of adults—namely, those more successful at identifying actions that had been seen more frequently than comparison sequences—were also successful at learning conditional-probability statistics. These experiments help to clarify the mechanisms subserving processing of intentional action, and they highlight important differences from, as well as similarities to, prior studies of statistical learning in other domains, including language.     

An Evaluation of Videomodeling on Fundamental Motor Skill Performance of Preschool Children

Proficiency in fundamental motor skills (FMS) is important for both the health and the overall growth and development of young children. To identify factors that facilitate the development of FMS, the study provided preliminary data on the effect of videomodeling (VM) on the acquisition of FMS by typically developing young children. Participants were six conveniently selected typically developing preschool-age children from an early care and education center. A multiple-baseline-across-participants single-subject research design was used to evaluate VM effects. Motor skill acquisition was assessed with validated developmental sequences of the standing long jump and the overarm throw. The results demonstrated that the VM intervention improved participants’ FMS performance and the improvement was maintained even after the withdrawal of the VM, 2 weeks after the last VM session. Qualitative data collected via a self-report enjoyment scale and field notes with the instructors elicited four factors that might have affected participants’ performance: their attention and motivation to perform the task and the skill complexity and reproduction. The data suggest that VM may be an efficient strategy for teaching FMS to preschool-age children.     

Effects of flaxseed<Emphasis Type="Italic">(Linum usitatissimum) chutney</Emphasis> on gamma-glutamyl transpeptidase and micronuclei profile in azoxymethane treated rats

Antioxidant property of flaxseed chutney was evident by decreasing lipid peroxidation (TBARS) and predictor enzyme γ-glutamyl transpeptidase profile and micronuclei formation in azoxymethane treated rats. After 10 weeks, rats fed with either fiber-free basal diet or Antioxidant diet exhibited over sevenfold increase in γ-glutamyl transpeptidase activity and nearly fourfold increase in micronuclei load in comparison to controls (p<0.001). A significant reduction in both γ-glutamyl transpeptidase level (52%) and micronuclei formation (47%) was observed in fiber-free basal diet/Antioxidant diet/flaxseed chutney diet fed rats. Relative to rats fed fiber-free basal diet, the profile of γ-glutamyl transpeptidase and micronuclei load was not significantly altered.     

Inside Out: Action Research from the Teacher–Researcher Perspective

Teachers enrolled in the master of natural science program for high school science teachers at a large research university must complete a year-long action research study. This account, by the program’s action research coordinator, describes both process and outcomes of this research experience from the perspectives of the research coordinator and the teacher–researchers, shedding light on the organizational learning that takes place, and the ways in which the research experience affected individual teacher–researchers. Teachers reported that their action research experience changed them in fundamental ways, providing them with a framework for deepening their understanding of student thinking, challenging their folk wisdom about teaching and learning, building confidence in their abilities and renewing their commitment to teaching as a vocation.     

Green’s functions for infinite planes and half-planes consisting of quasicrystal bi-materials

This paper deals with the combination of point phonon and phason forces applied in the interior of infinite planes and half-planes of 1D quasicrystal bi-materials. Based on the general solution of quasicrystals, a series of displacement functions are adopted to obtain Green＇s functions for infinite planes and bi-material planes composed of two half-planes in the closed form, when the two half-planes are supposed to be ideally bonded or to be in smooth contact. Since the physical quantities can be readily calculated without the need of performing any transform operations, Green＇s functions are very convenient to be used in the study of point defects and inhomogeneities in the quasicrystal materials.