Experimental verification of Faradaic charging in ac electrokinetics

This paper investigates the phenomenon of Faradaic charging in ac electrokinetics. Faradaic reactions were suggested as a key effect responsible for the reversal of pumping direction in ac micropumps. However, this hypothesis has yet to be proven convincingly and directly. Here we present an ion detection strategy to determine the production of ions through Faradaic hydrolytic reactions originating from direct application of voltage to electrolytic solutions during ac electrokinetics. Experiments were performed with symmetrical planar electrodes aligned along a microfluidic channel. Fluorescein, a pH-dependent dye, was employed as the pH indicator for the detection of ion production. Images were captured for analysis at various voltage levels. From analyzing the fluorescence intensity and its distribution, it can be concluded that the production of ions from hydrolytic reactions takes place and increases with the ac voltage. The coefficient of deviation indicates a significant enhancement at ac voltage above 11 V_pp. Lastly, we demonstrate a strategy using dc-biased ac electrokinetics to achieve controllability in direction and magnitude of the net fluid flow in pumping application.     

Numerical study of dc-biased ac-electrokinetic flow over symmetrical electrodes

This paper presents a numerical study of DC-biased AC-electrokinetic (DC-biased ACEK) flow over a pair of symmetrical electrodes. The flow mechanism is based on a transverse conductivity gradient created through incipient Faradaic reactions occurring at the electrodes when a DC-bias is applied. The DC biased AC electric field acting on this gradient generates a fluid flow in the form of vortexes. To understand more in depth the DC-biased ACEK flow mechanism, a phenomenological model is developed to study the effects of voltage, conductivity ratio, channel width, depth, and aspect ratio on the induced flow characteristics. It was found that flow velocity on the order of mm/s can be produced at higher voltage and conductivity ratio. Such rapid flow velocity is one of the highest reported in microsystems technology using electrokinetics.     

Collaborative inquiry project-based learning: Effects on reading ability and interests

The academic performance of students has been shown to be associated with reading ability. Inquiry learning can potentially enhance the reading abilities and interests of students. This study verified this proposition by examining the effects of an inquiry approach to group projects on the reading abilities of primary school students. Using a case study design, an inquiry project-based learning (PBL) approach, with the collaboration between three types of teachers and the school librarian was implemented to support the development of reading abilities and interests of students in a primary school in Hong Kong. The participants included Primary 4 students, teachers, and parents. Progress in International Reading Literacy Study (PIRLS) tests were used to evaluate the students' reading abilities; survey questionnaire and interviews were used to examine the participants' perceptions of the inquiry PBL; and the PIRLS survey was used to measure the students' attitudes and self-perceptions. Quantitative and qualitative data analyses showed positive effects on the reading abilities and attitudes of the participating students. Students' attitudes and self-perceived abilities appeared to influence the improvements in reading abilities. Finally, improvements in the students' reading comprehension, reading speed, and vocabulary were perceived. These findings provide evidence and insights to support further implementation of inquiry PBL in primary schools.     

Understanding the Ecologies of Education Reforms: Comparing the Perceptions of Parents and Secondary Teachers and Students in China

This study examines how secondary school teachers have implemented educational reforms in China. To examine the implementation process, we conducted teacher, student, and parent surveys. Teachers and students surveys asked questions on how often a teaching or evaluation strategy was used in a given course. The survey concluded that teachers and parents liked the reform initiatives, although some teachers still struggle with the transition to the new reforms, most were able to make the necessary changes to include some student-centred lessons. However, students claimed that teacher-directed lessons still dominate most classrooms and tests, class work, homework, and exams are still the most common evaluation systems. The surveys also revealed that classroom management needs increased attention as a result of the reforms. The largest problem, however, lies with the examination systems, as there is currently little room for introducing activity-based learning. Parents and society need to change their mind-sets of valuing examination achievements.     

Managing change in an integrated school--a Hong Kong hybrid experience

Following the world trend of inclusion in education, many schools in Hong Kong have started including students with special needs in the regular classrooms. Given the unique educational context of Hong Kong as 'East meets West', and given that inclusion is essentially a concept from the West, this paper argues that Hong Kong's integration has its unique hybrid features. This paper reports the experience of one primary school in the process of change in areas of stages of integration, leadership and whole school approach, during a two-year implementation period. Change processes at the school, classroom and individual levels are discussed. A case study methodology is used so that unique characteristics of the school in its naturalistic settings can be captured. Data were obtained from observation, documentary analysis, individual and group interviews of different school stakeholders: the principals, parents, teachers, resource teachers, and guidance personnel. Implications of findings to schools in Hong Kong and other countries facing similar issue in parallel and mixed cultural settings are discussed.     

Measuring Parameter Uncertainty by Identifying Fungible Estimates in SEM

Researchers require methods for evaluating whether statistical results are credible and thus, worthy of interpretation. An examination of fungible parameters estimates is a method in which the veracity of inferences can be strengthened or weakened by quantifying the level of support for individual parameter estimates as measured by the likelihood function. This new approach aims to overcome some of the limitations of previous methods and is based on a simplified computational and conceptual understanding of a fungible parameter estimate analysis. Additionally, this computational approach has been implemented in the R package psindex. This package provides a user-friendly, and free method for statisticians and applied researchers to investigate parameter stability in their own models using an analysis of fungible parameter estimates. Finally, an applied example illustrates fungible parameter estimate analysis in practice using the psindex package. General guidelines for interpretation are provided.     

Simulation of gait asymmetry and energy transfer efficiency between unilateral and bilateral amputees

Efficient walking or running requires symmetrical gait. Gait symmetry is one of the key factors in efficient human dynamics, kinematics and kinetics. The desire of individuals with a lower-limb amputation to participate in sports has resulted in the development of energy-storing-and-returning (ESR) feet. This paper analyses a case study to show the effect of symmetry and asymmetry as well as energy transfer efficiency during periodic jumping between simulated bilateral and unilateral runners. A custom gait analysis system is developed as part of this project to track the motion of the body of a physically active subject during a set of predefined motions. Stance and aerial times are accurately measured using a high speed camera. Gait frequency, the level of symmetry and the non-uniform displacement between left and right foot and their effects on the position of the Centre of Mass (CM) were used as criteria to calculate both peak energies and transformation efficiency. Gait asymmetry and discrepancy of energy transfer efficiency between the intact foot and the ESR are observed. It is concluded that unilateral runners require excessive effort to compensate for lack of symmetry as well as asymmetry in energy transfer, causing fatigue which could be a reason why bilateral amputee runners using ESR feet have a superior advantage over unilateral amputees.     

Fieldwork in Geography —importance,objectives and scope

As a subject concerned with the study of human activities in relation to the physical environment, geography should have a strong appeal to young people. Yet in many instances the subject evokes little interest and has even to justify its place in the curriculum. It is regrettable but true that in many of our schools geography is still largely taught as a compendium of facts about the world. Although more enlightened approaches are available, many teachers still cling to the traditional method for putting the subject across and emphasize learning of facts rather than understanding of principles. How can teachers avoid burdening the minds of children with mere factual information and make Geography more realistic, meaningful and intellectually challenging?     

An integrative perceptual approach for teaching Chinese characters

This paper is concerned with an innovative approach to teaching Chinese characters. Traditionally, pupils learn Chinese characters by repeatedly copying them until they can reproduce their form and pronunciation from memory. Most of the characters pupils are required to learn are selected on the basis of their frequency in adult written communications rather in everyday child usage. The process takes many years and is perceived by pupils as laborious and boring. The writers of the paper developed an approach based on the phenomenographic approach to learning and on various pioneering ways of teaching Chinese characters. Learning starts with the pupils’ own language and characters are introduced and used in contexts meaningful to the pupil, attention being drawn systematically to structural features, written form and pronunciation. Characters are learnt in relational clusters, similarities and variations among related characters in the clusters being used by teachers to highlight and emphasise crucial aspects of Chinese characters and words. The learning mastered serves as a foundation for subsequent learning. After an in-depth discussion of theory and pedagogy, the writers report an investigation in four primary schools in Hong Kong that yields strong support for the efficacy of the approach.     

From Behind the Pupil's Desk to the Teacher's Desk: A qualitative study of student teachers' professional learning in Hong Kong

This paper presents a qualitative study of student teachers' school-based learning in a teacher education program for secondary school teachers in Hong Kong. Learning to teach is examined through the lens of a personal-professional conceptualization of learning. An in-depth study of two cases of student teachers' professional learning is reported. Research methods used include interviewing, tape-recording supervisory meetings, field observation and document analysis. Through an inquiry into the individual's interaction with pre-training influences, the teacher education program and the teaching practice context in the two cases, this study extends our understanding of student teachers' professional learning in terms of the formation of the teaching self and the process of framing in the action and socio-professional contexts of teaching practice.