title: Heat pump bridge analysis using the modified energy transfer diagram

authors: Schlosser, Florian

subjects: Science & Technology

abstract: Heat pumps are the key technology to decarbonise thermal processes by upgrading industrial surplus heat using renewable electricity. Existing insight-based integration methods refer to the idealised Grand Composite Curve requiring the full exploitation of heat recovery potential but leave the question of how to deal with technical or economic limitations unanswered. In this work, a novel Heat Pump Bridge Analysis (HPBA) is introduced for practically targeting technical and economic heat pump potential by applying Coefficient of Performance curves into the Modified Energy Transfer Diagram (METD). Removing cross-Pinch violations and operating heat exchangers at minimum approach temperatures by combined application of Bridge Analysis increases the heat recovery rate and reduce the temperature lift to be pumped at the same time. The insight-based METD allows the individual matching of heat surpluses and deficits of individual streams with the capabilities and performance of different market-available heat pump concepts. For an illustrative example, the presented modifications based on HPBA increase the economically viable share of the technical heat pump potential from 61% to 79%.

text: Heat pump bridge analysis using the modified energy transfer diagram Heat pumps are the key technology to decarbonise thermal processes by upgrading industrial surplus heat using renewable electricity. Existing insight-based integration methods refer to the idealised Grand Composite Curve requiring the full exploitation of heat recovery potential but leave the question of how to deal with technical or economic limitations unanswered. In this work, a novel Heat Pump Bridge Analysis (HPBA) is introduced for practically targeting technical and economic heat pump potential by applying Coefficient of Performance curves into the Modified Energy Transfer Diagram (METD). Removing cross-Pinch violations and operating heat exchangers at minimum approach temperatures by combined application of Bridge Analysis increases the heat recovery rate and reduce the temperature lift to be pumped at the same time. The insight-based METD allows the individual matching of heat surpluses and deficits of individual streams with the capabilities and performance of different market-available heat pump concepts. For an illustrative example, the presented modifications based on HPBA increase the economically viable share of the technical heat pump potential from 61% to 79%.

year: 2021

title: Star Decompositions of Bipartite Graphs

authors: Lim, Nick Jin Sean

subjects: Graph Decomposition

abstract: In Chapter 1, we will introduce the definitions and the notations used throughout this thesis. We will also survey some prior research pertaining to graph decompositions, with special emphasis on star-decompositions and decompositions of bipartite graphs. Here we will also introduce some basic algorithms and lemmas that are used in this thesis.

In Chapter 2, we will focus primarily on decomposition of complete bipartite graphs. We will also cover the necessary and sufficient conditions for the decomposition of complete bipartite graphs minus a 1-factor, also known as crown graphs and show that all complete bipartite graphs and crown graphs have  a decomposition into stars when certain necessary conditions for the decomposition are met. This is an extension of the results given in "On claw-decomposition of complete graphs and complete bigraphs" by Yamamoto, et. al. We will propose a construction for the decomposition of the graphs. 

In Chapter 3, we focus on the decomposition of complete equipartite tripartite graphs. This result is similar to the results of "On Claw-decomposition of complete multipartite graphs" by Ushio and Yamamoto. Our proof is again by construction and we propose how it might extend to equipartite multipartite graphs. We will also discuss the 3-star decomposition of complete tripartite graphs.

In Chapter 4 , we will discuss the star decomposition of 4-regular bipartite graphs, with particular emphasis on the decomposition of 4-regular bipartite graphs into 3-stars. We will propose methods to extend our strategies to model the problem as an optimization problem. We will also look into the probabilistic method discussed in "Tree decomposition of Graphs" by Yuster and how we might modify the results of this paper to star decompositions of bipartite graphs. 

In Chapter 5, we summarize the findings in this thesis, and discuss the future work and research in star decompositions of bipartite and multipartite graphs.

text: Star Decompositions of Bipartite Graphs In Chapter 1, we will introduce the definitions and the notations used throughout this thesis. We will also survey some prior research pertaining to graph decompositions, with special emphasis on star-decompositions and decompositions of bipartite graphs. Here we will also introduce some basic algorithms and lemmas that are used in this thesis.

In Chapter 2, we will focus primarily on decomposition of complete bipartite graphs. We will also cover the necessary and sufficient conditions for the decomposition of complete bipartite graphs minus a 1-factor, also known as crown graphs and show that all complete bipartite graphs and crown graphs have  a decomposition into stars when certain necessary conditions for the decomposition are met. This is an extension of the results given in "On claw-decomposition of complete graphs and complete bigraphs" by Yamamoto, et. al. We will propose a construction for the decomposition of the graphs. 

In Chapter 3, we focus on the decomposition of complete equipartite tripartite graphs. This result is similar to the results of "On Claw-decomposition of complete multipartite graphs" by Ushio and Yamamoto. Our proof is again by construction and we propose how it might extend to equipartite multipartite graphs. We will also discuss the 3-star decomposition of complete tripartite graphs.

In Chapter 4 , we will discuss the star decomposition of 4-regular bipartite graphs, with particular emphasis on the decomposition of 4-regular bipartite graphs into 3-stars. We will propose methods to extend our strategies to model the problem as an optimization problem. We will also look into the probabilistic method discussed in "Tree decomposition of Graphs" by Yuster and how we might modify the results of this paper to star decompositions of bipartite graphs. 

In Chapter 5, we summarize the findings in this thesis, and discuss the future work and research in star decompositions of bipartite and multipartite graphs.

year: 2015

title: A critical interruption in the governance of a New Zealand state high school

authors: L'Huillier, Barbara Marie

subjects: governance

abstract: The governance of contemporary Western education aspires to serve the intertwining values of human emancipation and social inclusiveness in both the organisational form of educational institutions and their pedagogical direction. In New Zealand (NZ), what is understood as ‘good’ governance of education has varied over time according to economic conditions and political interests. The fourth Labour government (1984-1990), which undertook a widespread, rapid commitment to neo-liberal principles, reorganised the provision and governance of education along quasi public-private sector lines, explicitly using a business approach to guide practice, yet retaining hegemonic characteristics. This commitment to neo-liberal principles has been continued by all subsequent NZ governments. The intended transformation of the education system from a centrally-governed bureaucracy to a community-governed process has not been easy. Underpinning the new governance regime is an implied notion that school communities share a common understanding of what is meant by education, processes of representation, and of ‘good’ governance. However, due to the different aspirations members of school communities’ can hold for their respective schools this commonality of meaning can be a false dichotomy resulting in schools being governed in a state of tension. This tension serves to highlight contradictions and disconnections between the espoused aims of devolved governance and a State-mandated process that works to exclude certain factions of a school community. Increasing numbers of NZ school Boards of Trustees are experiencing these tensions and contradictions resulting in an interruption in school governance. The interruption I am interested in takes the form of the commodification of education that has been taking place in NZ since the mid 1980s. I argue this to be an interruption with profound effects on both the flourishing of individuals and the cohesion of communities and usefully serves to draw attention to the disconnection between the broad ideals of education, as articulated by the early promoters of a State-funded education system, and the neo-liberal re-visioning of State education. Fairfield College is a NZ State high school where the tensions and contradictions surrounding the meaning of education, processes of representation, and of good governance have generated a crisis resulting in a critical interruption in school governance. The school’s Board of Trustees received considerable media coverage between 2008 and 2009 regarding a critical interruption to their governance. This interruption presented a unique research opportunity to explore how the words used to frame the problems facing the Board of Trustees, the words used to explain and justify State intervention in the governance of the school, and the words used to propose solutions to perceived problems were invested with meaning. With my interest in connotative meaning, I illustrate how these words were used to encourage and endorse actions that comply with prevailing public policy. In this case study I examined how the school’s direction has been reconfigured according to the principles of corporate governance using a companion lexicon of business. Directives have been devised by various NZ governments to align education with the neo-liberal principles that have prevailed in the governance of this country since 1984. The multiple meanings attributed to ‘governance’ and ‘corporate governance’ in the relevant literatures, and the various implications for applied governance processes and dynamics, influenced my decision to adopt the dual orientation of social constructionism and critical theory to underpin this research. Social constructionists focus on how individuals and groups produce, disseminate, and validate their perceptions of reality. Critical theorists aim to create awareness of constraints to emancipatory potential and inclusiveness. They seek to expose the contradictions between espoused aims of justice and the flourishing of individuals and that which is practised, with the intention to contribute to changes that would enhance justice and the flourishing of individuals. One such contribution is to give voice to those who feel their voices are not being heard. Both theoretical schools regard the use of language as pivotal in the construction of social processes in which meaning is continually negotiated and re-negotiated by the stakeholders. In this research I engaged in audio-recorded semi-structured interviews with members from four stakeholder groups involved in the governance of Fairfield College: the Whānau Support Group (a predominantly Māori special interest group), parents and caregivers, teachers, and those previously or currently charged with governance responsibilities for the school. These narratives were then analysed using thematic analysis to provide important insights into how ‘governance’ of the school was interpreted, challenged, and/or endorsed. My research at Fairfield College indicates that the different constructions of ‘governance’ are associated with identifiable overlapping issues arranged in a hierarchy. The foundational tier represents the outcome of various NZ governments’ preference for market-generated principles of organisation at a macro State level, namely the commodification of public services – in this instance education. The middle tier addresses concerns raised by some stakeholders regarding their notion of inclusiveness and the vulnerability of the democratic process as experienced at community level. The top tier encompasses the twin issues of communication and consultation processes at a management level that appear to demonstrate a conflict between the State’s espoused principles of good governance and their application at Fairfield College. As a result of examining the critical interruption to the governance of Fairfield College I conclude that when viewed through the lens of a social constructionist orientation informed by critical theory, ‘governance’ in the education sector can be interpreted as a process supporting neo-liberal preferences for market-orientated approaches to education. Such preferences overshadow any other ideals held by members of the school’s community and, according to a critical understanding of neo-liberalism, weaken the principles of emancipation and inclusiveness. The insights generated from this research provide a basis for further research into the governance of other organisations with emancipatory and inclusive aspirations.

text: A critical interruption in the governance of a New Zealand state high school The governance of contemporary Western education aspires to serve the intertwining values of human emancipation and social inclusiveness in both the organisational form of educational institutions and their pedagogical direction. In New Zealand (NZ), what is understood as ‘good’ governance of education has varied over time according to economic conditions and political interests. The fourth Labour government (1984-1990), which undertook a widespread, rapid commitment to neo-liberal principles, reorganised the provision and governance of education along quasi public-private sector lines, explicitly using a business approach to guide practice, yet retaining hegemonic characteristics. This commitment to neo-liberal principles has been continued by all subsequent NZ governments. The intended transformation of the education system from a centrally-governed bureaucracy to a community-governed process has not been easy. Underpinning the new governance regime is an implied notion that school communities share a common understanding of what is meant by education, processes of representation, and of ‘good’ governance. However, due to the different aspirations members of school communities’ can hold for their respective schools this commonality of meaning can be a false dichotomy resulting in schools being governed in a state of tension. This tension serves to highlight contradictions and disconnections between the espoused aims of devolved governance and a State-mandated process that works to exclude certain factions of a school community. Increasing numbers of NZ school Boards of Trustees are experiencing these tensions and contradictions resulting in an interruption in school governance. The interruption I am interested in takes the form of the commodification of education that has been taking place in NZ since the mid 1980s. I argue this to be an interruption with profound effects on both the flourishing of individuals and the cohesion of communities and usefully serves to draw attention to the disconnection between the broad ideals of education, as articulated by the early promoters of a State-funded education system, and the neo-liberal re-visioning of State education. Fairfield College is a NZ State high school where the tensions and contradictions surrounding the meaning of education, processes of representation, and of good governance have generated a crisis resulting in a critical interruption in school governance. The school’s Board of Trustees received considerable media coverage between 2008 and 2009 regarding a critical interruption to their governance. This interruption presented a unique research opportunity to explore how the words used to frame the problems facing the Board of Trustees, the words used to explain and justify State intervention in the governance of the school, and the words used to propose solutions to perceived problems were invested with meaning. With my interest in connotative meaning, I illustrate how these words were used to encourage and endorse actions that comply with prevailing public policy. In this case study I examined how the school’s direction has been reconfigured according to the principles of corporate governance using a companion lexicon of business. Directives have been devised by various NZ governments to align education with the neo-liberal principles that have prevailed in the governance of this country since 1984. The multiple meanings attributed to ‘governance’ and ‘corporate governance’ in the relevant literatures, and the various implications for applied governance processes and dynamics, influenced my decision to adopt the dual orientation of social constructionism and critical theory to underpin this research. Social constructionists focus on how individuals and groups produce, disseminate, and validate their perceptions of reality. Critical theorists aim to create awareness of constraints to emancipatory potential and inclusiveness. They seek to expose the contradictions between espoused aims of justice and the flourishing of individuals and that which is practised, with the intention to contribute to changes that would enhance justice and the flourishing of individuals. One such contribution is to give voice to those who feel their voices are not being heard. Both theoretical schools regard the use of language as pivotal in the construction of social processes in which meaning is continually negotiated and re-negotiated by the stakeholders. In this research I engaged in audio-recorded semi-structured interviews with members from four stakeholder groups involved in the governance of Fairfield College: the Whānau Support Group (a predominantly Māori special interest group), parents and caregivers, teachers, and those previously or currently charged with governance responsibilities for the school. These narratives were then analysed using thematic analysis to provide important insights into how ‘governance’ of the school was interpreted, challenged, and/or endorsed. My research at Fairfield College indicates that the different constructions of ‘governance’ are associated with identifiable overlapping issues arranged in a hierarchy. The foundational tier represents the outcome of various NZ governments’ preference for market-generated principles of organisation at a macro State level, namely the commodification of public services – in this instance education. The middle tier addresses concerns raised by some stakeholders regarding their notion of inclusiveness and the vulnerability of the democratic process as experienced at community level. The top tier encompasses the twin issues of communication and consultation processes at a management level that appear to demonstrate a conflict between the State’s espoused principles of good governance and their application at Fairfield College. As a result of examining the critical interruption to the governance of Fairfield College I conclude that when viewed through the lens of a social constructionist orientation informed by critical theory, ‘governance’ in the education sector can be interpreted as a process supporting neo-liberal preferences for market-orientated approaches to education. Such preferences overshadow any other ideals held by members of the school’s community and, according to a critical understanding of neo-liberalism, weaken the principles of emancipation and inclusiveness. The insights generated from this research provide a basis for further research into the governance of other organisations with emancipatory and inclusive aspirations.

year: 2011