Dean-flow-coupled elasto-inertial three-dimensional particle focusing under viscoelastic flow in a straight channel with asymmetrical expansion–contraction cavity arrays

In this paper, 3D particle focusing in a straight channel with asymmetrical expansion–contraction cavity arrays (ECCA channel) is achieved by exploiting the dean-flow-coupled elasto-inertial effects. First, the mechanism of particle focusing in both Newtonian and non-Newtonian fluids was introduced. Then particle focusing was demonstrated experimentally in this channel with Newtonian and non-Newtonian fluids using three different sized particles (3.2 μm, 4.8 μm, and 13 μm), respectively. Also, the effects of dean flow (or secondary flow) induced by expansion–contraction cavity arrays were highlighted by comparing the particle distributions in a single straight rectangular channel with that in the ECCA channel. Finally, the influences of flow rates and distances from the inlet on focusing performance in the ECCA channel were studied. The results show that in the ECCA channel particles are focused on the cavity side in Newtonian fluid due to the synthesis effects of inertial and dean-drag force, whereas the particles are focused on the opposite cavity side in non-Newtonian fluid due to the addition of viscoelastic force. Compared with the focusing performance in Newtonian fluid, the particles are more easily and better focused in non-Newtonian fluid. Besides, the Dean flow in visco-elastic fluid in the ECCA channel improves the particle focusing performance compared with that in a straight channel. A further advantage is three-dimensional (3D) particle focusing that in non-Newtonian fluid is realized according to the lateral side view of the channel while only two-dimensional (2D) particle focusing can be achieved in Newtonian fluid. Conclusively, this novel Dean-flow-coupled elasto-inertial microfluidic device could offer a continuous, sheathless, and high throughput (>10 000 s⁻¹) 3D focusing performance, which may be valuable in various applications from high speed flow cytometry to cell counting, sorting, and analysis.     

Effects of self-questioning on EFL students’ engagement in literary reading / Los efectos del autocuestionamiento en la lectura comprometida de textos literarios de estudiantes de inglés como lengua extranjera

This study examines the effects of self-questioning on EFL students’ literary reading engagement. Two interventions were tested: (1) students generating questions while reading short stories, and then exploring their questions in small-groups; and (2) students generating questions while reading, and then reflecting through a free writing activity. Participants were 59 Vietnamese undergraduate students enrolled in an English as a foreign language course. A pre-test post-test control group design with switching replications was used, with a control condition in which the teacher (instead of the students) posed the questions. Students’ reading engagement was measured by a written response to a short story and a questionnaire. Results showed that both self-questioning interventions positively influenced students’ reading engagement compared to the control condition. A maintenance of effects was also observed. We conclude that self-questioning combined with group discussions or free writing promotes students’ reading engagement.     

Participatory agricultural research and decentralisation in Vietnam

Abstract

Based on a conceptual framework, that describes the relationship between the effectiveness of up-scaling participation and implementing decentralisation, the objective of this paper is to analyse the effectiveness of decentralisation measures in the Agricultural Technology System (ATS) of Vietnam. It discusses whether the decentralisation efforts so far have enabled the rural population to express their options and take joint decisions in the sense of participation. The paper uses primary and secondary data, collected between November 2000 and June 2001. The paper first discusses the theoretical literature on up-scaling participation and decentralisation. Emphasis is given to highlight the links between the concepts of good governance in decentralisation and its effects on people's participation in the decision making process. Thereafter, the Vietnamese decentralisation measures are reviewed and it is assessed to which extent the agricultural sector and its relevant state agencies have benefited from these efforts. The experiences from the decentralisation activities is summarised. Whether decentralisation opened space for the rural people to express their opinions and to ensure that their preferences are incorporated in the ATS is specially considered. The paper closes with recommendations.     

Vietnam: Challenges and Opportunities for Publishers

Little is known about the publishing industry and the cultural complexities of Vietnam and, therefore, this article provides a summary of the essential information and related data on the demographics of the country. The development of the publishing industry is traced from 1945 before the unification of North and South Vietnam in 1975 to the present status. The role of the book publishing industry is examined in relation to television and radio media. A review of the reading culture is presented to understand the current status and potential for printed books as well as E-books in Vietnam.     

The Proliferation of Piracy in the Publishing Supply Chains of Emerging Countries: A Study in Vietnam

Book piracy is a significant problem throughout the world and particularly in emerging countries. Such a phenomenon is costly to all participants in the publishing supply chain. This paper aims to investigate factors that influence Vietnamese students’ purchases of photocopied textbooks. The findings reveal that students’ purchases are motivated by their perceived value, subjective norms representing social influence and the lack of regulation enforcement. Using these findings, this paper suggests interventions for policymakers, publishers, distributors and universities to limit the purchase of pirated textbooks as well as to improve the value of original textbooks.     

Pre-service teachers’ construction of professional identity through peer collaboration during professional experience: a case study in Australia

Much research in the area of pre-service teacher (PST) identity formation has focused on the mentoring relationship between PSTs and their supervising teachers. While this is important to identity formation, interaction with peers is another area that needs to be examined. Using Wenger’s matrix as a theoretical framework, this study aimed to explore how PSTs’ identities are formed during the process of paired placement during the professional experience. Two pairs of PSTs were followed during the four-week professional experience. Data were collected from interviews with the PSTs before, during and after the professional experience. It is clear from this case study that the identity formation of PSTs is enhanced during a paired placement on their first professional experience. This finding has implications for teacher educators who are seeking evidence of the effectiveness of paired placements on the identity formation of PSTs during professional experience.     

Adolescent Perception of Potential High-Performing Classmates: A Cross-National Exploration

This study explores how secondary school students perceive high-performing potential classmates. A total of 1,794 seventh- and 10th-grade students from five countries completed a questionnaire measuring their expectations of hypothetical male and female high-performing classmates in three categories: intellectual ability, positive social qualities, and popularity. Across the five countries represented in this study, analyses of variance indicated that students did not report negative attitudes toward the three potential characteristics of a hypothetical gifted peer. Vietnamese students in particular reported more positive observations about the hypothetical classmate than their Australian, Peruvian, South Korean, and Spanish counterparts. Differing cross-national attitudes toward high-performing peers and the implications therein are discussed.