title: Microbial community structure and dynamics in wastewater treatment over a year

authors: Sanders, Shaun

abstract: Wastewater treatment plants are necessary for the release of effluent into the natural environment. The wastewater treatment plant functions as a bioreactor cultivating a diverse microbial community for the removal of nutrients such as carbon, nitrogen, and phosphorous from the effluent. The Tahuna treatment plant was the focus of this study because there was simultaneous removal of nitrogen and phosphorous, although the treatment plant was not designed for both these processes. Biochemical parameters were taken, specifically; dissolved oxygen, pH, oxidation-reduction potential, total suspended solids, total phosphorous, dissolved reactive phosphorous, nitrogen levels, and temperature. Through the use of Ion Torrent sequencing of the 16S rRNA gene, and analysis of sequences using the RDP and MIDAS databases, this study was able to elucidate the diversity of microbes within the Tahuna wastewater treatment plant. The analysis of the biochemical parameters and sequencing results revealed the presence and activity of functional groups of organisms important in wastewater. These organisms were involved in ammonium oxidation, nitrite oxidation, denitrification and phosphorous removal. Ammonium was metabolised by the ammonium oxidising bacteria Nitrosomonas producing nitrite. The nitrite was subsequently converted to nitrate by the nitrite oxidising bacteria Nitrospira. Finally, Dechloromonas functioned as a denitrifying phosphorous accumulating organism in the treatment plant. As a denitrifying phosphorous accumulating organism, Dechloromonas was able to metabolise nitrate into dinitrogen gas as well as accumulate phosphorous for removal. The community remained relatively stable over the course of the study, with CAP and CAA plots as well as ANCOM analysis revealing that the greatest driver of the microbial community was temporal change.

text: Microbial community structure and dynamics in wastewater treatment over a year Wastewater treatment plants are necessary for the release of effluent into the natural environment. The wastewater treatment plant functions as a bioreactor cultivating a diverse microbial community for the removal of nutrients such as carbon, nitrogen, and phosphorous from the effluent. The Tahuna treatment plant was the focus of this study because there was simultaneous removal of nitrogen and phosphorous, although the treatment plant was not designed for both these processes. Biochemical parameters were taken, specifically; dissolved oxygen, pH, oxidation-reduction potential, total suspended solids, total phosphorous, dissolved reactive phosphorous, nitrogen levels, and temperature. Through the use of Ion Torrent sequencing of the 16S rRNA gene, and analysis of sequences using the RDP and MIDAS databases, this study was able to elucidate the diversity of microbes within the Tahuna wastewater treatment plant. The analysis of the biochemical parameters and sequencing results revealed the presence and activity of functional groups of organisms important in wastewater. These organisms were involved in ammonium oxidation, nitrite oxidation, denitrification and phosphorous removal. Ammonium was metabolised by the ammonium oxidising bacteria Nitrosomonas producing nitrite. The nitrite was subsequently converted to nitrate by the nitrite oxidising bacteria Nitrospira. Finally, Dechloromonas functioned as a denitrifying phosphorous accumulating organism in the treatment plant. As a denitrifying phosphorous accumulating organism, Dechloromonas was able to metabolise nitrate into dinitrogen gas as well as accumulate phosphorous for removal. The community remained relatively stable over the course of the study, with CAP and CAA plots as well as ANCOM analysis revealing that the greatest driver of the microbial community was temporal change.

year: 2019

title: Fibrillation - Improving the fibre/matrix adhesion of lyocell fibres for use in short fibre-reinforced and 3D printed composites

authors: Graupner, Nina

subjects: additive manufacturing

abstract: This study investigates the influence of fibrillation of lyocell fibres on the mechanical properties of
compression moulded polylactide (PLA), polypropylene (PP) composites, and 3D printed PLA
composites. Fibrillation was shown to reduce the strength and elongation at break of the fibres without
affecting the Young's modulus compared to untreated fibres. Nevertheless, fibrillation in composites
resulted in a 1.15 higher strength for PP composites and 1.62 for PLA composites. Young’s modulus
and impact strength were increased by factors of 1.41 and 1.38 for PP composites and 1.2 and 1.23 for
PLA composites. Applying the fibrillated fibres in 3D printed PLA shows a significant increase in the
mechanical properties. For example, with a fibre mass fraction of 30%, the tensile strength of the
composites with fibrillated fibres was increased by a factor of 1.18 compared to composites with
untreated fibres. The use of maleic anhydride in the PLA matrix in combination with composite heat
treatment further increased the strength by a factor of 1.46. With a strength of 85 MPa, a Young's
modulus of 7.2 GPa and an elongation at break of 3.2%, these are some of the highest values reported
for this kind of 3D printed materials.

text: Fibrillation - Improving the fibre/matrix adhesion of lyocell fibres for use in short fibre-reinforced and 3D printed composites This study investigates the influence of fibrillation of lyocell fibres on the mechanical properties of
compression moulded polylactide (PLA), polypropylene (PP) composites, and 3D printed PLA
composites. Fibrillation was shown to reduce the strength and elongation at break of the fibres without
affecting the Young's modulus compared to untreated fibres. Nevertheless, fibrillation in composites
resulted in a 1.15 higher strength for PP composites and 1.62 for PLA composites. Young’s modulus
and impact strength were increased by factors of 1.41 and 1.38 for PP composites and 1.2 and 1.23 for
PLA composites. Applying the fibrillated fibres in 3D printed PLA shows a significant increase in the
mechanical properties. For example, with a fibre mass fraction of 30%, the tensile strength of the
composites with fibrillated fibres was increased by a factor of 1.18 compared to composites with
untreated fibres. The use of maleic anhydride in the PLA matrix in combination with composite heat
treatment further increased the strength by a factor of 1.46. With a strength of 85 MPa, a Young's
modulus of 7.2 GPa and an elongation at break of 3.2%, these are some of the highest values reported
for this kind of 3D printed materials.

year: 2024

title: The Waikato invasion 1863-1864: A counter-insurgency approach

authors: Swears, Calum Robert

subjects: Counterinsurgency

abstract: Counter-insurgency as a strategy has only been explicitly espoused in American and British military tactical manuals in recent decades. It is anachronistic to military terminology before the last half century, but as this thesis illustrates counter-insurgency can be seen in embryonic form in the conflicts of the 1860s between Indigenous Māori and invading British forces in Aotearoa New Zealand. This thesis examines how early counter-insurgency strategy was evident in the tactical and strategic approaches used by Crown forces during the invasion of the Waikato in 1863-64. It asks: what evidence of counter-insurgency strategy can be seen in both British and Māori tactics at the time, and were they planned and intentional? 
Using two recent counter-insurgency tactical manuals - one American and the other British - this study compares present-day counter-insurgency principles, philosophies, and approaches to examples of Māori and British strategies during the 1860’s wars in Waikato, New Zealand. It illustrates how the Crown’s “suppression of rebellion” served as the contemporary political wording for its counter-insurgency campaign, which effectively repositioned Indigenous peoples as insurgents and “rebels” in their own territories and legitimated British colonial authority. Thus, this study argues that counter-insurgency in British military history arose from the various colonial invasions and occupations it undertook over several centuries. In Aotearoa, as this thesis argues, counter-insurgency tactics were used to establish legitimacy through civil-military operations such as land seizure, public proclamations and reports that vilified Māori and asserted British governing authority. The history of counter-insurgency as it is understood in British and American military thinking today, then, as this study contends is deeply connected to, and informed by, powerful colonial discourses, strategies, and experiences similar to those explored in this study of the Waikato invasion.

text: The Waikato invasion 1863-1864: A counter-insurgency approach Counter-insurgency as a strategy has only been explicitly espoused in American and British military tactical manuals in recent decades. It is anachronistic to military terminology before the last half century, but as this thesis illustrates counter-insurgency can be seen in embryonic form in the conflicts of the 1860s between Indigenous Māori and invading British forces in Aotearoa New Zealand. This thesis examines how early counter-insurgency strategy was evident in the tactical and strategic approaches used by Crown forces during the invasion of the Waikato in 1863-64. It asks: what evidence of counter-insurgency strategy can be seen in both British and Māori tactics at the time, and were they planned and intentional? 
Using two recent counter-insurgency tactical manuals - one American and the other British - this study compares present-day counter-insurgency principles, philosophies, and approaches to examples of Māori and British strategies during the 1860’s wars in Waikato, New Zealand. It illustrates how the Crown’s “suppression of rebellion” served as the contemporary political wording for its counter-insurgency campaign, which effectively repositioned Indigenous peoples as insurgents and “rebels” in their own territories and legitimated British colonial authority. Thus, this study argues that counter-insurgency in British military history arose from the various colonial invasions and occupations it undertook over several centuries. In Aotearoa, as this thesis argues, counter-insurgency tactics were used to establish legitimacy through civil-military operations such as land seizure, public proclamations and reports that vilified Māori and asserted British governing authority. The history of counter-insurgency as it is understood in British and American military thinking today, then, as this study contends is deeply connected to, and informed by, powerful colonial discourses, strategies, and experiences similar to those explored in this study of the Waikato invasion.

year: 2022