Microfluidic conformal coating of non-spherical magnetic particles

We present the conformal coating of non-spherical magnetic particles in a co-laminar flow microfluidic system. Whereas in the previous reports spherical particles had been coated with thin films that formed spheres around the particles; in this article, we show the coating of non-spherical particles with coating layers that are approximately uniform in thickness. The novelty of our work is that while liquid-liquid interfacial tension tends to minimize the surface area of interfaces—for example, to form spherical droplets that encapsulate spherical particles—in our experiments, the thin film that coats non-spherical particles has a non-minimal interfacial area. We first make bullet-shaped magnetic microparticles using a stop-flow lithography method that was previously demonstrated. We then suspend the bullet-shaped microparticles in an aqueous solution and flow the particle suspension with a co-flow of a non-aqueous mixture. A magnetic field gradient from a permanent magnet pulls the microparticles in the transverse direction to the fluid flow, until the particles reach the interface between the immiscible fluids. We observe that upon crossing the oil-water interface, the microparticles become coated by a thin film of the aqueous fluid. When we increase the two-fluid interfacial tension by reducing surfactant concentration, we observe that the particles become trapped at the interface, and we use this observation to extract an approximate magnetic susceptibility of the manufactured non-spherical microparticles. Finally, using fluorescence imaging, we confirm the uniformity of the thin film coating along the entire curved surface of the bullet-shaped particles. To the best of our knowledge, this is the first demonstration of conformal coating of non-spherical particles using microfluidics.     

It's in the Name: A Synthetic Inquiry of the Knowledge Is Power Program [KIPP]

The task of this article is to interrogate the Knowledge Is Power Program (KIPP) model to develop a more robust understanding of a prominent trend in the charter school movement and education policy more generally. To accomplish this task, this article details the findings of a synthetic analysis that examines the KIPP model as a Hegelian whole concept operative in a specific mode of social reality. The guidance for this analysis is grounded in a rather straightforward research question. Given the prominence that the KIPP model has achieved in the charter school movement in the United States, what can a synthetic analysis tell us about not only KIPP, but also the larger charter school movement?     

Rethinking ‘leadership’ in education: a research agenda

Knowledge production in educational leadership, management and administration has been, and continues to be, seduced by fads. One of the most significant trends in recent decades has been the ascendancy of ‘leadership’. In this introductory paper, I both introduce the contributions to this special issue and, more importantly, locate this collection within the intellectual tradition of disruptive Australian scholarship and the discourses of JEAH. Specifically, I argue that this collection of papers provides new ways for thinking about leadership, leaders and leading grounded in histories not bounded by historical categories, images and metaphors. This issue is however not the final word, and I encourage the reader to think with, beyond and where necessary against what is argued in the spirit of the intellectual enterprise.     

ANNUAL INDEX Volume 71 Fall 2002-Summer 2003

In this study, the authors aimed to examine 8 of the different methods for computing confidence intervals around alpha that have been proposed to determine which of these, if any, is the most accurate and precise. Monte Carlo methods were used to simulate samples under known and controlled population conditions wherein the underlying item distribution is nonnormal and when the items’ responses are those of rating scales rather than dichotomous items. Overall, one can conclude that, despite concerns expressed over the use of Fisher's method for coefficient alpha, in general, it actually outperformed the other methods. Larger sample sizes and larger coefficient alphas also resulted in better band coverage, whereas smaller number of items resulted in poorer band coverage.     

The commercial transformation of public education

This essay reviews the history of school commercialization in the USA and the forms that it has taken over time, with particular attention paid to research measuring the scope and variety of commercialization trends in US public schools. The implications of commercialization activities such as those that promote the consumption of nutritionally deficient foods and beverages are explored. The argument is made that the values inherent in the consumerist ideology used to support school privatization conflict with the democratic values on which public education has been historically based. Edison Schools is discussed as a model of the for‐profit management of public schools and emerging forms of school commercialization are considered. Finally, the role of free trade agreements in promoting school commercialism and privatization is described.     

Can the integration of field and classroom-based learning enhance writing? The life on our shore case study

There is a need to evaluate the benefits to children of integrated classroom and field-based learning. In this article, we describe a case study that involves children in the production of a field guide: an authentic task which integrates learner autonomy and open enquiry with field work, information and communication technologies (ICT) and classroom-based activities. We consider the impact that this task has had upon aspects of the children's factual writing. Although we found no improvement in the ability of the children to write sentences and only a marginal improvement in their ability to write for composition and effect, we did find a significant improvement in their ability to write about the ecology of an animal that they had encountered firsthand when compared to an animal that they had not encountered in life.     

Recognising desire: a psychosocial approach to understanding education policy implementation and effect

It is argued that in order to understand the ways in which teachers experience their work—including the idiosyncratic ways in which they respond to and implement mandated education policy—it is necessary to take account both of sociological and of psychological issues. The paper draws on original research with practising and beginning teachers, and on theories of social and psychic induction, to illustrate the potential benefits of this bipartisan approach for both teachers and researchers. Recognising the significance of (but somewhat arbitrary distinction between) structure and agency in teachers’ practical and ideological positions, it is suggested that teachers’ responses to local and central policy changes are governed by a mix of pragmatism, social determinism and often hidden desires. It is the often under‐acknowledged strength of desire that may tip teachers into accepting and implementing policies with which they are not ideologically comfortable.