Sealing SU-8 microfluidic channels using PDMS

A simple method of irreversibly sealing SU-8 microfluidic channels using PDMS is reported in this paper. The method is based on inducing a chemical reaction between PDMS and SU-8 by first generating amino groups on PDMS surface using N₂ plasma treatment, then allowing the amino groups to react with the residual epoxy groups on SU-8 surface at an elevated temperature. The N₂ plasma treatment of PDMS can be conducted using an ordinary plasma chamber and high purity N₂, while the residual epoxy groups on SU-8 surface can be preserved by post-exposure baking SU-8 at a temperature no higher than 95 °C. The resultant chemical bonding between PDMS and SU-8 using the method create an interface that can withstand a stress that is greater than the bulk strength of PDMS. The bond is permanent and is long-term resistant to water. The method was applied in fabricating SU-8 microfluidi-photonic integrated devices, and the obtained devices were tested to show desirable performance.     

Examining the influences of epistemic beliefs and knowledge representations on cognitive processing and conceptual change when learning physics

The purpose of this study was to investigate the role of epistemic beliefs and knowledge representations in cognitive and metacognitive processing when learning about physics concepts through text. Specifically, we manipulated the representation of physics concepts in texts about Newtonian mechanics and explored how these texts interacted with individuals’ epistemic beliefs to facilitate or constrain learning. Results revealed that when individuals’ epistemic beliefs were consistent with the knowledge representations in their assigned texts, they performed better on various measures of learning (use of processing strategies, text recall, and changes in misconceptions) than when their epistemic beliefs were inconsistent with the knowledge representations. These results have implications for how researchers conceptualize epistemic beliefs and support contemporary views regarding the context sensitivity of individuals’ epistemic beliefs.     

Changing Teachers' Thinking Through Critical Constructivism and Critical Action Research

Abstract

This paper studies attempts to change teachers' thinking towards a construc‐tivist perspective within science education. The contexts surrounding the research are important: ideas of critical constructivism, critical action research and the work of Paulo Freire are brought to bear on teacher education in Recife, northeastern Brazil. A professional development course was designed to explore with secondary science teachers some elements of constructivist thinking, and to shape action research projects within their own classrooms. The course design is described, along with some of the responses of the participants both during and after they undertook their projects within their secondary schools. The responses highlight the tensions of trying to innovate with ‘non‐traditional methods’ within traditional situations, the advantages and drawbacks of ‘freeing up’ classroom discussion and authoritative teaching.     

Appreciating the Complexity of Project Management Execution: Using Simulation in the Classroom

As the popularity and importance of project management increase, so does the need for well‐prepared project managers. This article discusses our experiences using a project management simulation in undergraduate and MBA classes to help students better grasp the complexity of project management. This approach gives students hands‐on experience with many facets in the project management life cycle and provides them with feedback on their performance as project managers. This article provides an overview of the simulation exercises, guidance for classroom integration, and evidence of effectiveness.