Kinetics study on biomass pyrolysis for fuel gas production

Kinetic knowledge is of great importance in achieving good control of the pyrolysis and gasification process and optimising system design. An overall kinetic pyrolysis scheme is therefore addressed here. The kinetic modelling incorporates the following basic steps: the degradation of the virgin biomass materials into primary products (tar, gas and semi-char), the decomposition of primary tar into secondary products and the continuous interaction between primary gas and char. The last step is disregarded completely by models in the literature. Analysis and comparison of predicted results from different kinetic schemes and experimental data on our fixed bed pyrolyser yielded very positive evidence to support our kinetic scheme. Project (No. 2001CB409600) Supported by the National Key Basic Research Program (973) of China     

The Key Stage 3 Strategy: what kind of reform is this?

The Key Stage 3 Strategy is a complex and evolving government strategy intended to improve the education of 11‐ to 14‐year‐olds in England. This paper provides a snapshot of its development by early 2004, drawing on our evaluation of the pilot phase which began in 2000. The evolution of the Strategy, with its phased introduction of both subject and cross‐curricular strands, is described. We then examine the policy intentions and evidence base which underpin it before considering what the Strategy offers in terms of curricular and pedagogical reform. While the Strategy seeks to improve schooling for 11‐ to 14‐year‐olds, it has struggled to offer a coherent approach, though recent changes in emphasis may help. We conclude that a more radical approach to the learning needs of 11‐ to 14‐year‐olds is needed and draw evidence from international trends in middle years education.     

The cooking teacher: investigating gender stereotypes in a Korean kindergarten

This article discusses some findings from a small‐scale investigation of children's gendered beliefs and behaviours in a Korean kindergarten which was attempting to challenge gender stereotyping through the anti‐bias intervention of a ‘cooking curriculum’. A sample of 14 children, some with ‘working’ mothers and some with ‘housewife’ mothers, was observed for two months, and informally interviewed on several occasions. The children's mothers were also interviewed. The findings are situated in the context of the changing, but still traditional, culture of Korean society, as well as in the contexts of early childhood education and theories of gender acquisition. They confirm that, although children are highly likely to reproduce the beliefs current in their home environment, they are open to reconstructing these views when actively challenged to consider alternatives, either by the school curriculum or by engaging in debate with a researcher or practitioner. The nature of the ‘alternative’ views available may however be problematic.     

Teaching Undergraduate Mathematics on the Internet

This is Part 2 of a two-part study of how APOS theory may be used to provide cognitive explanations of how students and mathematicians might think about the concept of infinity. We discuss infinite processes, describe how the mental mechanisms of interiorization and encapsulation can be used to conceive of an infinite process as a completed totality, explain the relationship between infinite processes and the objects that may result from them, and apply our analyses to certain mathematical issues related to infinity.     

Improving the precision of the keyword-matching pornographic text filtering method using a hybrid model

With the flooding of pornographic information on the Internet, how to keep people away from that offensive information is becoming one of the most important research areas in network information security. Some applications which can block or filter such information are used. Approaches in those systems can be roughly classified into two kinds:metadata based and content based. With the development of distributed technologies, content based filtering technologies will play a more and more important role in filtering systems. Keyword matching is a content based method used widely in harmful text filtering. Experiments to evaluate the recall and precision of the method showed that the precision of the method is not satisfactory, though the recall of the method is rather high. According to the results, a new pornographic text filtering model based on reconfirming is put forward. Experiments showed that the model is practical, has less loss of recall than the single keyword matching method, and has higher precision.     

Theory Competition and the Process of Change

The reasons why many educational change initiatives have little impact are often framed in terms of either a poorly designed process on the part of the change initiator, or in terms of problems with the attitudes, skills and/or knowledge of those responsible for implementation. In this paper, we seek to integrate these two perspectives more closely by focusing on their interface and the competing theories frequently held by the change initiators and implementers. This concept of theory competition is illustrated with a case of a national literacy initiative in New Zealand in which the change initiators wished to raise the achievement of low performing students through the development of “learning-centred” leadership in schools and evidence-based practice. The desired outcomes were not achieved because theories about what it means to be a successful leader in such a situation, the data needed to undertake the type of evidence-based analysis envisioned and school personnel beliefs about the target students were understood differently by those responsible for initiating the change and those responsible for implementing it.