title: Derivation and experimental analysis of Peukert’s equation in terms of fractional equivalent circuits

authors: Cree, Michael J.

abstract: Using an equivalent circuit model (ECM) of a battery that involves fractional elements we analytically derive Peukert’s empirical equation along with generalisations of the equation for the increasing capacity of the battery as the charge and discharge currents are reduced. The derived generalised Peukert’s Equations are dimensionally consistent and all parameters (including Peukert’s coefficient and the so-called ‘capacity constant’) can be calculated from the parameters of the ECM and operating voltage range of the battery. Experiments are conducted on ten batteries to demonstrate that the resistor fractional-capacitor series ECM fit to discharge times predicts well the impedance spectrum found by electrochemical impedance spectroscopy (EIS), and vice versa, on Li-CO/NCA/NMC and Na-ion batteries. This agreement is not observed on the tested LiFePO
 and LiTO batteries because the impedance spectrum exhibits behaviour not captured by the ECM. Peukert’s Equation predicts ever increasing capacity as both the charge and discharge currents are reduced. The experimental results confirm this behaviour for all batteries down to the lowest current measured (C/256).

text: Derivation and experimental analysis of Peukert’s equation in terms of fractional equivalent circuits Using an equivalent circuit model (ECM) of a battery that involves fractional elements we analytically derive Peukert’s empirical equation along with generalisations of the equation for the increasing capacity of the battery as the charge and discharge currents are reduced. The derived generalised Peukert’s Equations are dimensionally consistent and all parameters (including Peukert’s coefficient and the so-called ‘capacity constant’) can be calculated from the parameters of the ECM and operating voltage range of the battery. Experiments are conducted on ten batteries to demonstrate that the resistor fractional-capacitor series ECM fit to discharge times predicts well the impedance spectrum found by electrochemical impedance spectroscopy (EIS), and vice versa, on Li-CO/NCA/NMC and Na-ion batteries. This agreement is not observed on the tested LiFePO
 and LiTO batteries because the impedance spectrum exhibits behaviour not captured by the ECM. Peukert’s Equation predicts ever increasing capacity as both the charge and discharge currents are reduced. The experimental results confirm this behaviour for all batteries down to the lowest current measured (C/256).

year: 2026-02

title: The development of teacher self and collective efficacy through a research practice partnership project

authors: Edwards, Frances

abstract: This paper outlines the affordances provided through teacher engagement in an educational research partnership project for the development of teacher self-efficacy and collective teacher efficacy. Six teachers, previously involved in a successful two-year project, chose to commit to continuing to research and develop their practice. They agreed to focus on whole class teaching which was an area of interest for their community of schools. This qualitative study utilised audio recordings of workshops, and artefacts produced by these teachers. Data was analysed thematically. Findings show there was clear evidence of growing individual and collective teacher efficacy as teachers used common language and shared and analysed student data over time. The teachers also became more prominent in their role as teacher leaders and proactive and engaged in planning for student improvement within and across their schools. Factors that contributed to teacher self-efficacy and collective efficacy were identified. Implications for teachers and schools are discussed.

text: The development of teacher self and collective efficacy through a research practice partnership project This paper outlines the affordances provided through teacher engagement in an educational research partnership project for the development of teacher self-efficacy and collective teacher efficacy. Six teachers, previously involved in a successful two-year project, chose to commit to continuing to research and develop their practice. They agreed to focus on whole class teaching which was an area of interest for their community of schools. This qualitative study utilised audio recordings of workshops, and artefacts produced by these teachers. Data was analysed thematically. Findings show there was clear evidence of growing individual and collective teacher efficacy as teachers used common language and shared and analysed student data over time. The teachers also became more prominent in their role as teacher leaders and proactive and engaged in planning for student improvement within and across their schools. Factors that contributed to teacher self-efficacy and collective efficacy were identified. Implications for teachers and schools are discussed.

year: 2025

title: Insecure, unpredictable, hoping to survive: Four cases of Māori people living precariously in Hamilton, Aotearoa New Zealand

authors: Uerata, Lynley Moana

subjects: Māori

abstract: A conceptualisation of precarity is introduced and adopted. A critique of contemporary conceptualisations of precarity is presented, drawing especially on Stuart Hall’s interpretation of articulation and Marx’s concept of relative surplus population. Much of the literature on precarity focusses on the neoliberal mode of contemporary capitalism originating in the late 1970s. However, there is limited literature which explores precarity as a way of life. A precarious way of life is characterised by interacting forms of precarity which embed insecurity, instability, and unpredictability in the everyday lives of real people. An account of the Māori experience of precarity since the pre-colonial era to the present-day is presented. Māori are the indigenous people of Aotearoa New Zealand who were colonised by the British Empire in the 1800s. 
The main research questions addressed in my thesis are: What forms of precarity are present in the everyday context? How do forms of precarity relate to each other? How do forms of precarity relate to being Māori? What kinds of support do those living with precarity gain from social structures, institutions, and social actors? What is the role of culture in the way Māori experience and mediate precarity? An analysis of semi-structured in-depth engagements with Māori people living precariously in Hamilton, Aotearoa New Zealand in 2016, based on four case studies, shows the character and significance of forms, sources, and effects of precarity in everyday life. As historical processes continue to overdetermine experiences of social structures and institutions in the present, in a contemporary capitalist context precarity arises from a wide range of interacting sources, forms, and effects of precarity. Among the different kinds of actors and organisations which comprise the support systems constructed to mediate precarity in the everyday context, cultural practices and resources can play a significant role for people who are culturally connected. When people are integrated into their local and cultural communities, they can cope better with a precarious way of life.

text: Insecure, unpredictable, hoping to survive: Four cases of Māori people living precariously in Hamilton, Aotearoa New Zealand A conceptualisation of precarity is introduced and adopted. A critique of contemporary conceptualisations of precarity is presented, drawing especially on Stuart Hall’s interpretation of articulation and Marx’s concept of relative surplus population. Much of the literature on precarity focusses on the neoliberal mode of contemporary capitalism originating in the late 1970s. However, there is limited literature which explores precarity as a way of life. A precarious way of life is characterised by interacting forms of precarity which embed insecurity, instability, and unpredictability in the everyday lives of real people. An account of the Māori experience of precarity since the pre-colonial era to the present-day is presented. Māori are the indigenous people of Aotearoa New Zealand who were colonised by the British Empire in the 1800s. 
The main research questions addressed in my thesis are: What forms of precarity are present in the everyday context? How do forms of precarity relate to each other? How do forms of precarity relate to being Māori? What kinds of support do those living with precarity gain from social structures, institutions, and social actors? What is the role of culture in the way Māori experience and mediate precarity? An analysis of semi-structured in-depth engagements with Māori people living precariously in Hamilton, Aotearoa New Zealand in 2016, based on four case studies, shows the character and significance of forms, sources, and effects of precarity in everyday life. As historical processes continue to overdetermine experiences of social structures and institutions in the present, in a contemporary capitalist context precarity arises from a wide range of interacting sources, forms, and effects of precarity. Among the different kinds of actors and organisations which comprise the support systems constructed to mediate precarity in the everyday context, cultural practices and resources can play a significant role for people who are culturally connected. When people are integrated into their local and cultural communities, they can cope better with a precarious way of life.

year: 2021