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: Impacts of Early Childhood Education Social Obligations on Families and Whanau

authors: Randall, Judith

subjects: early childhood education

abstract: This thesis explores the impacts of ECE social obligations on affected families and whānau. In 2013 ECE social obligations were introduced through the Social Security (Benefit Categories and Work Focus) Amendment Bill. These obligations require beneficiaries to ensure their children are “enrolled in and attending an approved early childhood education programme from the age of three, until they start school” (Work and Income New Zealand, 2013c). 
A qualitative approach was utilised to hear the voices of those affected. Data was gathered through interviews with eight beneficiary families and two ECE centre managers who had knowledge of the impacts of obligations.  Perceived impacts were analysed using thematic analysis. An examination of the discourses underpinning these obligations as represented in policy documents was undertaken utilising Bacchi’s (2000; 1999) “what’s the problem?” framework.
The introduction of the ECE social obligation policy was found to have placed responsibility on beneficiaries but to have failed to adequately address barriers to ECE participation that families face. The study identified many barriers which impede a family’s ability to participate in ECE. These include transportation, cost, and provision of high quality, suitable ECE for their children available in their local community. Mandatory ECE does not provide the infrastructure needed to enable families to access ECE programmes as it does not address the accessibility, structural, and personal barriers that families face. The thesis argues that the context of incorporating ECE policy in Ministry of Social Development (MSD) legislation and the use of sanctions to ensure compliance is likely to lead to negative outcomes for children’s well-being. 
Policy-as-discourse analysis identified that social obligations were conceived in the context of reducing long-term benefit dependency. The three interrelated dominant discourses underpinning this policy, economic rationalisation, the positioning of beneficiaries as job seekers, and the positioning of children as vulnerable, has left the child as citizen invisible. I advocate that redefining the problem through a child as citizen lens could provide a framework for government to support families through barriers and address provision of high quality ECE. 
Three key suggestions are made. Firstly, utilisation of a child’s rights framework could ensure children’s rights are at the forefront of ECE policy.  This would enable the primary emphasis to be on the welfare and best interests of all children. Within this framework this study identified the need for ECE matters to be in the jurisdiction of the Ministry of Education, rather than MSD, in order to ensure consistency and accessibility to quality ECE for all children. Secondly, ECE engagement needs to be promoted through a positive model rather than sanctions. Government financial investment in integrated ECE services within local communities could aid families to overcome participation barriers and provide an ideal model for enabling families to access social services.  Thirdly, government policy and funding needs to support provision of high quality ECE services that are responsive to their local communities. Such services are essential to encouraging ECE participation.

text: Impacts of Early Childhood Education Social Obligations on Families and Whanau This thesis explores the impacts of ECE social obligations on affected families and whānau. In 2013 ECE social obligations were introduced through the Social Security (Benefit Categories and Work Focus) Amendment Bill. These obligations require beneficiaries to ensure their children are “enrolled in and attending an approved early childhood education programme from the age of three, until they start school” (Work and Income New Zealand, 2013c). 
A qualitative approach was utilised to hear the voices of those affected. Data was gathered through interviews with eight beneficiary families and two ECE centre managers who had knowledge of the impacts of obligations.  Perceived impacts were analysed using thematic analysis. An examination of the discourses underpinning these obligations as represented in policy documents was undertaken utilising Bacchi’s (2000; 1999) “what’s the problem?” framework.
The introduction of the ECE social obligation policy was found to have placed responsibility on beneficiaries but to have failed to adequately address barriers to ECE participation that families face. The study identified many barriers which impede a family’s ability to participate in ECE. These include transportation, cost, and provision of high quality, suitable ECE for their children available in their local community. Mandatory ECE does not provide the infrastructure needed to enable families to access ECE programmes as it does not address the accessibility, structural, and personal barriers that families face. The thesis argues that the context of incorporating ECE policy in Ministry of Social Development (MSD) legislation and the use of sanctions to ensure compliance is likely to lead to negative outcomes for children’s well-being. 
Policy-as-discourse analysis identified that social obligations were conceived in the context of reducing long-term benefit dependency. The three interrelated dominant discourses underpinning this policy, economic rationalisation, the positioning of beneficiaries as job seekers, and the positioning of children as vulnerable, has left the child as citizen invisible. I advocate that redefining the problem through a child as citizen lens could provide a framework for government to support families through barriers and address provision of high quality ECE. 
Three key suggestions are made. Firstly, utilisation of a child’s rights framework could ensure children’s rights are at the forefront of ECE policy.  This would enable the primary emphasis to be on the welfare and best interests of all children. Within this framework this study identified the need for ECE matters to be in the jurisdiction of the Ministry of Education, rather than MSD, in order to ensure consistency and accessibility to quality ECE for all children. Secondly, ECE engagement needs to be promoted through a positive model rather than sanctions. Government financial investment in integrated ECE services within local communities could aid families to overcome participation barriers and provide an ideal model for enabling families to access social services.  Thirdly, government policy and funding needs to support provision of high quality ECE services that are responsive to their local communities. Such services are essential to encouraging ECE participation.

year: 2014

title: Microplastics in the marine environment: Sediment contaminant and bioaccumulation rates in bivalves within the Bay of Plenty

authors: Lewis, Anita

subjects: Microplastic

abstract: Microplastic pollution is recognised as a significant anthropogenic issue in coastal ecosystems around the world. The accumulation of microplastics in coastal environments causes both direct and indirect effects on these already vulnerable ecosystems. Limited information was available of the scale of microplastic pollution across New Zealand, including the Bay of Plenty. To enable a greater understanding of microplastic accumulation in sediment and bioaccumulation in bivalves sampling  within the Bay of Plenty area was conducted.
The presence of  microplastic particles was investigated from sediment and shellfish samples collected across the Bay of Plenty, from Waihī Beach in the West, to Ōpōtiki in the East. Three species of shellfish were collected that differed in their functional feeding modes (filter feeder vs deposit feeder): tuangi (cockle: Austrovenus stuchburyi), hanikura (wedge shell: Macomona liliana), and tuatua (surf clam: Paphies subtriangulata). Microplastic particles from sediment and bivalves were separated from the sediment and shellfish samples in the laboratory and identified using visual light stereomicroscopy. Microplastic particles were identified and quantified into three categories: fragments, fibres, and films. 
Significant numbers of fibres, as well as some fragments and films were found to be present in the sediment throughout all sampling locations. The highest density of microplastic particles in sediment (up to 11,087.9 per m²) were observed at sites that were closed to municipal sewage outfalls and populated areas, and the lowest densities were observed at Matakana Island (63 particles per m²). Sites in Ōhiwa Harbour showed an average of 504.6 particles per m² at the high tide zone and 477.6 particles per m² at the intertidal zone in the sediment. Ohiwa Harbour showed similar levels of microplastic accumulation in sediment compared to Tauranga Harbour. However, higher levels of microplastic particles were found in the sediment at open coast sites.
All shellfish sampled had at least one microplastic particle found in their tissues. The highest number of microplastics in shellfish were found in the wedge shell (23 particles), with the least from the cockles (1). Statistical analysis reveal that the deep burrowing deposit feeder (Macomona liliana) demonstrated an elevated amount of microplastic particles ingested relative to the shallow burrowing suspension feeding cockle (Austrovenus stutchburyi). A notable amount of microplastic particles were also found at all sampling locations for the culturally important tuatua (Paphies subtriangulata). However, comparing all three bivalve species, the deposit feeding M. liliana, ingested higher amounts than both the A. stutchburyi and P. subtriangulata, which could be related to their different functional feeding modes in the marine environment. This research provides baseline information to assess the extent of microplastic pollution in sediments and the potential for bioaccumulation in bivalve species with differentiated feeding modes and functional roles in the marine environment. 
The problem with microplastics is a global emerging contaminant. Preventing the problem of plastic wastes in New Zealand will require change across all aspects of society, along with policy regulations to mitigate the issue of microplastic pollution.

text: Microplastics in the marine environment: Sediment contaminant and bioaccumulation rates in bivalves within the Bay of Plenty Microplastic pollution is recognised as a significant anthropogenic issue in coastal ecosystems around the world. The accumulation of microplastics in coastal environments causes both direct and indirect effects on these already vulnerable ecosystems. Limited information was available of the scale of microplastic pollution across New Zealand, including the Bay of Plenty. To enable a greater understanding of microplastic accumulation in sediment and bioaccumulation in bivalves sampling  within the Bay of Plenty area was conducted.
The presence of  microplastic particles was investigated from sediment and shellfish samples collected across the Bay of Plenty, from Waihī Beach in the West, to Ōpōtiki in the East. Three species of shellfish were collected that differed in their functional feeding modes (filter feeder vs deposit feeder): tuangi (cockle: Austrovenus stuchburyi), hanikura (wedge shell: Macomona liliana), and tuatua (surf clam: Paphies subtriangulata). Microplastic particles from sediment and bivalves were separated from the sediment and shellfish samples in the laboratory and identified using visual light stereomicroscopy. Microplastic particles were identified and quantified into three categories: fragments, fibres, and films. 
Significant numbers of fibres, as well as some fragments and films were found to be present in the sediment throughout all sampling locations. The highest density of microplastic particles in sediment (up to 11,087.9 per m²) were observed at sites that were closed to municipal sewage outfalls and populated areas, and the lowest densities were observed at Matakana Island (63 particles per m²). Sites in Ōhiwa Harbour showed an average of 504.6 particles per m² at the high tide zone and 477.6 particles per m² at the intertidal zone in the sediment. Ohiwa Harbour showed similar levels of microplastic accumulation in sediment compared to Tauranga Harbour. However, higher levels of microplastic particles were found in the sediment at open coast sites.
All shellfish sampled had at least one microplastic particle found in their tissues. The highest number of microplastics in shellfish were found in the wedge shell (23 particles), with the least from the cockles (1). Statistical analysis reveal that the deep burrowing deposit feeder (Macomona liliana) demonstrated an elevated amount of microplastic particles ingested relative to the shallow burrowing suspension feeding cockle (Austrovenus stutchburyi). A notable amount of microplastic particles were also found at all sampling locations for the culturally important tuatua (Paphies subtriangulata). However, comparing all three bivalve species, the deposit feeding M. liliana, ingested higher amounts than both the A. stutchburyi and P. subtriangulata, which could be related to their different functional feeding modes in the marine environment. This research provides baseline information to assess the extent of microplastic pollution in sediments and the potential for bioaccumulation in bivalve species with differentiated feeding modes and functional roles in the marine environment. 
The problem with microplastics is a global emerging contaminant. Preventing the problem of plastic wastes in New Zealand will require change across all aspects of society, along with policy regulations to mitigate the issue of microplastic pollution.

year: 2021