title: Ensuring cost-effective heat exchanger network design for non-continuous processes

authors: Morrison, Andrew S.

subjects: Capital costs

abstract: The variation in stream conditions over time inevitably adds significant complexity to the task of integrating non-continuous processes. The Time Averaging Method (TAM), where stream conditions are simply averaged across the entire time cycle, leads to unrealistic energy targets for direct heat recovery and consequently to Heat Exchanger Network (HEN) designs that are in fact suboptimal. This realisation led to the development of the Time Slice Method (TSM) that instead considers each time interval separately, and can be used to reach accurate targets and to design the appropriate HEN to maximise heat recovery. However, in practise the HENs often require excessive exchanger surface area, which renders them unfeasible when capital costs are taken in to account. An extension of the TSM that reduces the required overall exchanger surface area and systematically distributes it across the stream matches is proposed. The methodology is summarised with the help of a simple case study and further improvement opportunities are discussed

text: Ensuring cost-effective heat exchanger network design for non-continuous processes The variation in stream conditions over time inevitably adds significant complexity to the task of integrating non-continuous processes. The Time Averaging Method (TAM), where stream conditions are simply averaged across the entire time cycle, leads to unrealistic energy targets for direct heat recovery and consequently to Heat Exchanger Network (HEN) designs that are in fact suboptimal. This realisation led to the development of the Time Slice Method (TSM) that instead considers each time interval separately, and can be used to reach accurate targets and to design the appropriate HEN to maximise heat recovery. However, in practise the HENs often require excessive exchanger surface area, which renders them unfeasible when capital costs are taken in to account. An extension of the TSM that reduces the required overall exchanger surface area and systematically distributes it across the stream matches is proposed. The methodology is summarised with the help of a simple case study and further improvement opportunities are discussed

year: 2012

title: ApproXFILTER - an approximative XML filter

authors: Michel, Yann-Rudolf

subjects: computer science

abstract: Publish/subscribe systems filter published documents and inform their subscribers about documents matching their interests. Recent systems have focussed on documents or messages sent in XML format. Subscribers have to be familiar with the underlying XML format to create meaningful subscriptions. A service might support several providers with slightly differing formats, e.g., several publishers of books. This makes the definition of a successful subscription almost impossible. We propose the use of an approximative language for subscriptions.We introduce the design our ApproXFILTER algorithm for approximative filtering
in a pub/sub system. We present the results of our analysis of a prototypical implementation.

text: ApproXFILTER - an approximative XML filter Publish/subscribe systems filter published documents and inform their subscribers about documents matching their interests. Recent systems have focussed on documents or messages sent in XML format. Subscribers have to be familiar with the underlying XML format to create meaningful subscriptions. A service might support several providers with slightly differing formats, e.g., several publishers of books. This makes the definition of a successful subscription almost impossible. We propose the use of an approximative language for subscriptions.We introduce the design our ApproXFILTER algorithm for approximative filtering
in a pub/sub system. We present the results of our analysis of a prototypical implementation.

year: 2005-01-01

title: “I learned quite a lot of the Maths stuff now that I think of it”: Māori Medium Students reflecting on their Initial Teacher Education

authors: Hawera, Ngārewa

subjects: initial teacher education

abstract: Research involving preservice or initial teacher education (ITE) indicates that mathematics education is a vital component of study. Little is known however, of indigenous student views of their compulsory mathematics education courses for a teaching degree. This research contributes to that knowledge space as it explores Māori medium ITE students’ perceptions of mathematics education in Aotearoa New Zealand. A thematic and qualitative analysis of a focused group discussion provides insights into key factors that students reported as significant links between their university and practicum experiences (teaching practice in schools). Some suggestions for strengthening that programme were also expressed. Findings indicate that factors linked to teacher ‘cultural competencies’, including an ethic of care, respectful relationships, revision of content knowledge, language learning, assessment practices, exposure to different ideas and planning and pedagogy were important. Navigating student-mentor teacher tensions as well as clarifying the significance of ideas in texts were highlighted as areas for strengthening. Mathematics educators preparing students for indigenous primary school settings may find this study useful.

text: “I learned quite a lot of the Maths stuff now that I think of it”: Māori Medium Students reflecting on their Initial Teacher Education Research involving preservice or initial teacher education (ITE) indicates that mathematics education is a vital component of study. Little is known however, of indigenous student views of their compulsory mathematics education courses for a teaching degree. This research contributes to that knowledge space as it explores Māori medium ITE students’ perceptions of mathematics education in Aotearoa New Zealand. A thematic and qualitative analysis of a focused group discussion provides insights into key factors that students reported as significant links between their university and practicum experiences (teaching practice in schools). Some suggestions for strengthening that programme were also expressed. Findings indicate that factors linked to teacher ‘cultural competencies’, including an ethic of care, respectful relationships, revision of content knowledge, language learning, assessment practices, exposure to different ideas and planning and pedagogy were important. Navigating student-mentor teacher tensions as well as clarifying the significance of ideas in texts were highlighted as areas for strengthening. Mathematics educators preparing students for indigenous primary school settings may find this study useful.

year: 2017