title: Investigating the vertical structure of sediment fluxes across an intertidal mudflat

authors: Beisly, Toby

subjects: Oceanography

abstract: Muddy coastal environments consisting of fine grained, cohesive sediment, are important systems for their provision of crucial ecosystem services and unique ecology. Such environments are governed by complex sediment transport patterns connecting the system to the wider coastal environment. To understand sediment transport it is necessary to measure suspended sediment concentrations and current velocities, from which, sediment fluxes can be estimated. Measurements of suspended sediment concentration (SSC) are typically carried out through the use of a variety of instruments, including, optical backscatter sensors or acoustic backscatter sensors; while acoustic doppler velocimeters, electromagnetic current meters and acoustic doppler current profilers are used to provide measurements of flow velocities.  
To reliably estimate sediment flux, accurate vertical profiles of SSC and currents are required. Despite the need for profile information, typically flux calculations are based on observations from a single measurement location and exploited through the water column. However, the sensitivity of flux measurements to the vertical resolution (e.g., number of instruments) or to the method of extrapolation is rarely quantified. 
This study elucidates the significant sensitivity of measurements to the instrument arrangement and technique used to extrapolate the data. Our results, taken in the field under real life conditions, indicate that single, or even double, vertical instrument arrangements are likely to have a large margin of error associated with any resulting flux estimates. However, a more even spread of instruments over the water column appears to give a more accurate estimate of flux. We find that under calm conditions (small waves) the Rouse SSC models provide a good estimate of SSC while the velocity model; law of the wall, contains significant uncertainty in its velocity estimates. These results demonstrate the uncertainty associated with such dynamic environments, and as such, the need for robust measurement techniques and an understanding of the vertical structure of SSC and currents. Such understanding of sediment transport is crucial for making informed decisions around the management of intertidal muddy environments.

text: Investigating the vertical structure of sediment fluxes across an intertidal mudflat Muddy coastal environments consisting of fine grained, cohesive sediment, are important systems for their provision of crucial ecosystem services and unique ecology. Such environments are governed by complex sediment transport patterns connecting the system to the wider coastal environment. To understand sediment transport it is necessary to measure suspended sediment concentrations and current velocities, from which, sediment fluxes can be estimated. Measurements of suspended sediment concentration (SSC) are typically carried out through the use of a variety of instruments, including, optical backscatter sensors or acoustic backscatter sensors; while acoustic doppler velocimeters, electromagnetic current meters and acoustic doppler current profilers are used to provide measurements of flow velocities.  
To reliably estimate sediment flux, accurate vertical profiles of SSC and currents are required. Despite the need for profile information, typically flux calculations are based on observations from a single measurement location and exploited through the water column. However, the sensitivity of flux measurements to the vertical resolution (e.g., number of instruments) or to the method of extrapolation is rarely quantified. 
This study elucidates the significant sensitivity of measurements to the instrument arrangement and technique used to extrapolate the data. Our results, taken in the field under real life conditions, indicate that single, or even double, vertical instrument arrangements are likely to have a large margin of error associated with any resulting flux estimates. However, a more even spread of instruments over the water column appears to give a more accurate estimate of flux. We find that under calm conditions (small waves) the Rouse SSC models provide a good estimate of SSC while the velocity model; law of the wall, contains significant uncertainty in its velocity estimates. These results demonstrate the uncertainty associated with such dynamic environments, and as such, the need for robust measurement techniques and an understanding of the vertical structure of SSC and currents. Such understanding of sediment transport is crucial for making informed decisions around the management of intertidal muddy environments.

year: 2023

title: Foaming behavior of novatein and blends with polyethylene compatibilised by maleic anhydride

authors: Gavin, Chanelle Anne Rose

subjects: Science & Technology

abstract: Novatein® thermoplastic protein (NTP), a bloodmeal based thermoplastic, was successfully foamed without blowing agent or blending with other polymers using a BOY-35A injection moulder in free expansion mode. Previously, only soy protein has been successfully continuously foamed and zein and gluten batch foamed without blending or rheological modification. The greatest expansion ratio for NTP was 4.4 at 165°C. Blending NTP with compatibilised LLDPE and LDPE and adding blowing agent reduced expansion ratios. The foams exhibited a fibrous nature, with cell structures similar to those reported in literature for extrusion foamed thermoplastic soy protein isolate. SEM pictures suggested a possible role of either sodium sulphite, sodium dodecyl sulphate or sodium sulphate as a nucleating agent as particulates were found on the cell surfaces. Triethylene glycol and urea were thought to contribute to NTP foaming, along with water present in NTP, with two or more acting as the blowing agent.

text: Foaming behavior of novatein and blends with polyethylene compatibilised by maleic anhydride Novatein® thermoplastic protein (NTP), a bloodmeal based thermoplastic, was successfully foamed without blowing agent or blending with other polymers using a BOY-35A injection moulder in free expansion mode. Previously, only soy protein has been successfully continuously foamed and zein and gluten batch foamed without blending or rheological modification. The greatest expansion ratio for NTP was 4.4 at 165°C. Blending NTP with compatibilised LLDPE and LDPE and adding blowing agent reduced expansion ratios. The foams exhibited a fibrous nature, with cell structures similar to those reported in literature for extrusion foamed thermoplastic soy protein isolate. SEM pictures suggested a possible role of either sodium sulphite, sodium dodecyl sulphate or sodium sulphate as a nucleating agent as particulates were found on the cell surfaces. Triethylene glycol and urea were thought to contribute to NTP foaming, along with water present in NTP, with two or more acting as the blowing agent.

year: 2017

title: Housing quality, health and whānau wellbeing

authors: Kukutai, Tahu

abstract: Shelter is a basic human need (Maslow 1943) and access to housing is a fundamental human right. A house is more than a physical dwelling that offers shelter; for many, it is a space that provides structure and meaning, and relates to feelings, emotions, memories and experiences, whether raising a whānau or discovering newfound independence. 
For Māori, the multi-layered concept of kāinga is broader still. Literally meaning ‘village’, kāinga is a home space where identity, whakapapa and whenua come together (Henare 2014). Kāinga is where individuals and whānau can sustain and care for themselves and others through practices of whanaungatanga (connecting with kin) and manaakitanga (acts of reciprocal caring). 
Kāinga is also closely related to the concept of tūrangawaewae, denoting a sense of physical and spiritual belonging or attachment to a place. Kāinga and tūrangawaewae thus share similarities with the meaning of home but mean much more than simply ‘being housed’ (Brown 2017). 
While housing and housing quality form only part of what it means to be ‘at home’, access to a warm, dry, safe, secure and watertight house is a basic right for all whānau and tamariki. 
In this section, we focus on the relationships between housing quality, health and wellbeing to better understand the extent of housing quality issues that whānau Māori face, and how housing quality, in turn, affects health and wellbeing. To our knowledge, this is the first nationally representative study that focuses specifically on Māori assessments of housing quality. It does so using data from the Māori Social Survey Te Kupenga.

text: Housing quality, health and whānau wellbeing Shelter is a basic human need (Maslow 1943) and access to housing is a fundamental human right. A house is more than a physical dwelling that offers shelter; for many, it is a space that provides structure and meaning, and relates to feelings, emotions, memories and experiences, whether raising a whānau or discovering newfound independence. 
For Māori, the multi-layered concept of kāinga is broader still. Literally meaning ‘village’, kāinga is a home space where identity, whakapapa and whenua come together (Henare 2014). Kāinga is where individuals and whānau can sustain and care for themselves and others through practices of whanaungatanga (connecting with kin) and manaakitanga (acts of reciprocal caring). 
Kāinga is also closely related to the concept of tūrangawaewae, denoting a sense of physical and spiritual belonging or attachment to a place. Kāinga and tūrangawaewae thus share similarities with the meaning of home but mean much more than simply ‘being housed’ (Brown 2017). 
While housing and housing quality form only part of what it means to be ‘at home’, access to a warm, dry, safe, secure and watertight house is a basic right for all whānau and tamariki. 
In this section, we focus on the relationships between housing quality, health and wellbeing to better understand the extent of housing quality issues that whānau Māori face, and how housing quality, in turn, affects health and wellbeing. To our knowledge, this is the first nationally representative study that focuses specifically on Māori assessments of housing quality. It does so using data from the Māori Social Survey Te Kupenga.

year: 2018