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Research Papers, Lincoln University

Mitigating the cascade of environmental damage caused by the movement of excess reactive nitrogen (N) from land to sea is currently limited by difficulties in precisely and accurately measuring N fluxes due to variable rates of attenuation (denitrification) during transport. This thesis develops the use of the natural abundance isotopic composition of nitrate (δ15N and δ18O of NO₃-) to integrate the spatialtemporal variability inherent to denitrification, creating an empirical framework for evaluating attenuation during land to water NO₃- transfers. This technique is based on the knowledge that denitrifiers kinetically discriminate against 'heavy' forms of both N and oxygen (O), creating a parallel enrichment in isotopes of both species as the reaction progresses. This discrimination can be quantitatively related to NO₃- attenuation by isotopic enrichment factors (εdenit). However, while these principles are understood, use of NO₃- isotopes to quantify denitrification fluxes in non-marine environments has been limited by, 1) poor understanding of εdenit variability, and, 2) difficulty in distinguishing the extent of mixing of isotopically distinct sources from the imprint of denitrification. Through a combination of critical literature analysis, mathematical modelling, mesocosm to field scale experiments, and empirical studies on two river systems over distance and time, these short comings are parametrised and a template for future NO₃- isotope based attenuation measurements outlined. Published εdenit values (n = 169) are collated in the literature analysis presented in Chapter 2. By evaluating these values in the context of known controllers on the denitrification process, it is found that the magnitude of εdenit, for both δ15N and δ18O, is controlled by, 1) biology, 2) mode of transport through the denitrifying zone (diffusion v. advection), and, 3) nitrification (spatial-temporal distance between nitrification and denitrification). Based on the outcomes of this synthesis, the impact of the three factors identified as controlling εdenit are quantified in the context of freshwater systems by combining simple mathematical modelling and lab incubation studies (comparison of natural variation in biological versus physical expression). Biologically-defined εdenit, measured in sediments collected from four sites along a temperate stream and from three tropical submerged paddy fields, varied from -3‰ to -28‰ depending on the site’s antecedent carbon content. Following diffusive transport to aerobic surface water, εdenit was found to become more homogeneous, but also lower, with the strength of the effect controlled primarily by diffusive distance and the rate of denitrification in the sediments. I conclude that, given the variability in fractionation dynamics at all levels, applying a range of εdenit from -2‰ to -10‰ provides more accurate measurements of attenuation than attempting to establish a site-specific value. Applying this understanding of denitrification's fractionation dynamics, four field studies were conducted to measure denitrification/ NO₃- attenuation across diverse terrestrial → freshwater systems. The development of NO₃- isotopic signatures (i.e., the impact of nitrification, biological N fixation, and ammonia volatilisation on the isotopic 'imprint' of denitrification) were evaluated within two key agricultural regions: New Zealand grazed pastures (Chapter 4) and Philippine lowland submerged rice production (Chapter 5). By measuring the isotopic composition of soil ammonium, NO₃- and volatilised ammonia following the bovine urine deposition, it was determined that the isotopic composition of NO₃ - leached from grazed pastures is defined by the balance between nitrification and denitrification, not ammonia volatilisation. Consequently, NO₃- created within pasture systems was predicted to range from +10‰ (δ15N)and -0.9‰ (δ18O) for non-fertilised fields (N limited) to -3‰ (δ15N) and +2‰ (δ18O) for grazed fertilised fields (N saturated). Denitrification was also the dominant determinant of NO₃- signatures in the Philippine rice paddy. Using a site-specific εdenit for the paddy, N inputs versus attenuation were able to be calculated, revealing that >50% of available N in the top 10 cm of soil was denitrified during land preparation, and >80% of available N by two weeks post-transplanting. Intriguingly, this denitrification was driven by rapid NO₃- production via nitrification of newly mineralised N during land preparation activities. Building on the relevant range of εdenit established in Chapters 2 and 3, as well as the soil-zone confirmation that denitrification was the primary determinant of NO₃- isotopic composition, two long-term longitudinal river studies were conducted to assess attenuation during transport. In Chapter 6, impact and recovery dynamics in an urban stream were assessed over six months along a longitudinal impact gradient using measurements of NO₃- dual isotopes, biological populations, and stream chemistry. Within 10 days of the catastrophic Christchurch earthquake, dissolved oxygen in the lowest reaches was <1 mg l⁻¹, in-stream denitrification accelerated (attenuating 40-80% of sewage N), microbial biofilm communities changed, and several benthic invertebrate taxa disappeared. To test the strength of this method for tackling the diffuse, chronic N loading of streams in agricultural regions, two years of longitudinal measurements of NO₃- isotopes were collected. Attenuation was negatively correlated with NO₃- concentration, and was highly dependent on rainfall: 93% of calculated attenuation (20 kg NO₃--N ha⁻¹ y⁻¹) occurred within 48 h of rainfall. The results of these studies demonstrate the power of intense measurements of NO₃- stable isotope for distinguishing temporal and spatial trends in NO₃ - loss pathways, and potentially allow for improved catchment-scale management of agricultural intensification. Overall this work now provides a more cohesive understanding for expanding the use of NO₃- isotopes measurements to generate accurate understandings of the controls on N losses. This information is becoming increasingly important to predict ecosystem response to future changes, such the increasing agricultural intensity needed to meet global food demand, which is occurring synergistically with unpredictable global climate change.

Research papers, University of Canterbury Library

The recent Canterbury earthquake sequence in 2010-2011 highlighted a uniquely severe level of structural damage to modern buildings, while confirming the high vulnerability and life threatening of unreinforced masonry and inadequately detailed reinforced concrete buildings. Although the level of damage of most buildings met the expected life-safety and collapse prevention criteria, the structural damage to those building was beyond economic repair. The difficulty in the post-event assessment of a concrete or steel structure and the uneconomical repairing costs are the big drivers of the adoption of low damage design. Among several low-damage technologies, post-tensioned rocking systems were developed in the 1990s with applications to precast concrete members and later extended to structural steel members. More recently the technology was extended to timber buildings (Pres-Lam system). This doctoral dissertation focuses on the experimental investigation and analytical and numerical prediction of the lateral load response of dissipative post-tensioned rocking timber wall systems. The first experimental stages of this research consisted of component testing on both external replaceable devices and internal bars. The component testing was aimed to further investigate the response of these devices and to provide significant design parameters. Post-tensioned wall subassembly testing was then carried out. Firstly, quasi-static cyclic testing of two-thirds scale post-tensioned single wall specimens with several reinforcement layouts was carried out. Then, an alternative wall configuration to limit displacement incompatibilities in the diaphragm was developed and tested. The system consisted of a Column-Wall-Column configuration, where the boundary columns can provide the support to the diaphragm with minimal uplifting and also provide dissipation through the coupling to the post-tensioned wall panel with dissipation devices. Both single wall and column-wall-column specimens were subjected to drifts up to 2% showing excellent performance, limiting the damage to the dissipating devices. One of the objectives of the experimental program was to assess the influence of construction detailing, and the dissipater connection in particular proved to have a significant influence on the wall’s response. The experimental programs on dissipaters and wall subassemblies provided exhaustive data for the validation and refinement of current analytical and numerical models. The current moment-rotation iterative procedure was refined accounting for detailed response parameters identified in the initial experimental stage. The refined analytical model proved capable of fitting the experimental result with good accuracy. A further stage in this research was the validation and refinement of numerical modelling approaches, which consisted in rotational spring and multi-spring models. Both the modelling approaches were calibrated versus the experimental results on post-tensioned walls subassemblies. In particular, the multi-spring model was further refined and implemented in OpenSEES to account for the full range of behavioural aspects of the systems. The multi-spring model was used in the final part of the dissertation to validate and refine current lateral force design procedures. Firstly, seismic performance factors in accordance to a Force-Based Design procedure were developed in accordance to the FEMA P-695 procedure through extensive numerical analyses. This procedure aims to determine the seismic reduction factor and over-strength factor accounting for the collapse probability of the building. The outcomes of this numerical analysis were also extended to other significant design codes. Alternatively, Displacement-Based Design can be used for the determination of the lateral load demand on a post-tensioned multi-storey timber building. The current DBD procedure was used for the development of a further numerical analysis which aimed to validate the procedure and identify the necessary refinements. It was concluded that the analytical and numerical models developed throughout this dissertation provided comprehensive and accurate tools for the determination of the lateral load response of post-tensioned wall systems, also allowing the provision of design parameters in accordance to the current standards and lateral force design procedures.

Images, UC QuakeStudies

Photograph captioned by BeckerFraserPhotos, "A sign on the fence of a red zoned property in Lower Styx Road. The sign reads, 'Browlee an (sic) Sutton R Clowns. Haven't got it right! $75 He rip off'. Many of the homeowners in this area believe that their homes should not be red zoned as the damage is much less than in other red zoned areas".

Images, UC QuakeStudies

A photograph of a man cooking sausages outside the Avonhead Baptist Church for the administrators and technicians from the Department of Civil and Natural Resources Engineering at the University of Canterbury. The students and staff from this department used the church as a base after the 22 February 2011 earthquake, until their building on campus was deemed safe to enter.

Images, UC QuakeStudies

One end of the Arts Centre photographed shortly after the 22 February 2011 earthquake. The gable of the building has crumbled and fallen to the ground, collapsing an awning. A large crack can be seen in the corner tower. Blue ties can be seen at the top of the tower, used to brace the structure after the 4 September 2010. This has probably limited the damage caused by the 22 February 2011 earthquake.

Images, UC QuakeStudies

An image from a Army News March 2011 photo compilation titled, "All in a Days Work". The image is captioned, "A container of equipment is off-loaded from a C-130 Hercules". This equipment is a generator sent down from Auckland to support Christchurch after the 22 February 2011 earthquake.

Images, UC QuakeStudies

A night-time photograph of the Cranmer Court building on the corner of Kilmore and Montreal Streets. The building has been lit up from below. The octagonal section on the corner of the building was the part occupied by Plato Creative from March 2008 to November 2009. Although designed to house a book depot, this section was used as the principal's office while Christchurch Normal School was operating from the building.

Images, UC QuakeStudies

A black and white, night-time photograph of the Cranmer Court building on the corner of Kilmore and Montreal Streets. The building has been lit up from below. The octagonal section on the corner of the building was the part occupied by Plato Creative from March 2008 to November 2009. Although designed to house a book depot, this section was used as the principal's office while Christchurch Normal School was operating from the building.

Audio, Radio New Zealand

Topics - Hundreds of people have lost their lives in Egypt overnight, and it's expected the death toll will continue to rise. This comes after the military over threw the democratically elected leader last month, and has now forcibly closed down protester camps. Power company Orion - owned by Christchurch City Council and Selwyn District Council - is looking to hike its prices until 2019, to help recover revenue lost because of the Canterbury earthquakes.

Audio, Radio New Zealand

The Christchurch City Council has confirmed the demolition of the earthquake-damaged Lancaster Park sports stadium will begin this year. Lancaster Park Cricket club was one of the sports ground's first tenants when it was established in 1881. An act of parliament means the ground has to be used for sport and recreation. "We're certainly looking foward to being able to get back on the ground and for it to be turned back into green space," Ric Horsfall from the cricket club says.

Audio, Radio New Zealand

In the programme this week - the former New Zealand cricket captain Stephen Fleming talks about plans for a charity cricket match to raise funds for victims of the Canterbury earthquake. We hear about the role of sports chaplaincy in New Zealand sports teams, Blyth Tait talks about his return to top level Equestrian competition after a seven year absence and one of the country's premier mountain biking events, the Karapoti Classic, near Wellington is underway again.

Audio, Radio New Zealand

Highlights from Radio New Zealand National's programmes for the week ending Friday 9 September. This week .... New Zealanders getting savvy about price discrimination, sorting the News from the TV programmes, studying coral reefs to save them from extinction, we remember sports braodcaster Graeme Moody, the World of Wearable Arts travels to Hong Kong, and we have a series of features and interviews from a weekend of commemorating a year of earthquakes in Canterbury.

Images, UC QuakeStudies

Two men carry backpacks and shopping bags along Tuam Street, stepping over emergency tape that lies across the road. Brick dust covers the street where fallen bricks have been cleared. The photographer comments, "Two members of our office carrying gear through the cordon. This was taken shortly after the 4th September earthquake. Police allowed us free access past the cordon and simply advised us to watch out for falling masonry. The access situation was much different after the February aftershock".

Images, UC QuakeStudies

A damaged car sits on top of the rubble of the Bealey Pharmacy. The photographer comments, "Bealey Avenue is open to traffic, as are many of the side streets, and the damage to buildings along this street is quite impressive and perhaps just a small taste of the damage that lies beyond the cordon ... A new feature now also appears to be a large pile of rubble with a new looking red Holden placed on top. Weird".

Images, UC QuakeStudies

A night-time photograph of the Cranmer Court building on the corner of Kilmore and Montreal Streets. The building has been lit up from below. The octagonal section on the corner of the building was the part occupied by Plato Creative from March 2008 to November 2009. Although designed to house a book depot, this section was used as the principal's office while Christchurch Normal School was operating from the building.

Images, UC QuakeStudies

A proposed design by John Raven for a new cathedral, tied to a cordon fence. Clarendon Tower can be seen in the background. The photographer comments, "Someone is asking for designs for a new Christchurch Cathedral after it was announced that the old historical building will not be repaired, to be put on the fences through which people can see the de-construction of the old one. This design looks a great one to me".

Articles, UC QuakeStudies

An edited copy of the pdf transcript of Laura's second earthquake story, captured by the UC QuakeBox Take 2 project. At the participant's request, parts of this transcript have been redacted. Interviewer: Jennifer Middendorf. Transcriber: Laura Moir.

Images, UC QuakeStudies

An access point into the CBD cordon at the corner of Gloucester and Oxford Terrace. Road cones and fencing can be seen in the background with a sign saying 'Access point. Hours of operation 6am-7pm daily. Outside this house use Manchester St/Cambridge Terrace access point'. Inside the cordon, a station can be seen on the left, as well as some workers and cars. The demolition site at the back is where the Brannigans Building used to be.

Images, UC QuakeStudies

Photograph captioned by Fairfax, "Christchurch Earthquake. Christchurch was rocked by a large aftershock shortly after 8am this morning. Social Development Minister Paula Bennett has donated money to the thousand of students who have filled the suburbs lending a hand to residents to clean up their properties. Bennett chats to volunteers (L-R) Sophie Cornish, Ashley Cornish, Laura Jackson, Shannon Ronald, Kirsten Glasson and Lauren Baker".

Images, UC QuakeStudies

A photograph of Graeme Kershaw, Technician at the University of Canterbury Department of Physics and Astronomy, sitting among the damaged parts of the Townsend Telescope. The telescope was damaged during the 22 February 2011 earthquake, when the Observatory tower at the Christchurch Arts Centre collapsed. Kershaw has been given the task of restoring the telescope. In this photograph he is holding the telescope's clock drive.

Images, UC QuakeStudies

A photograph of Graeme Kershaw, Technician at the University of Canterbury Department of Physics and Astronomy, sitting among the damaged parts of the Townsend Telescope. The telescope was damaged during the 22 February 2011 earthquake, when the Observatory tower at the Christchurch Arts Centre collapsed. Kershaw has been given the task of restoring the telescope. In this photograph he is holding the telescope's clock drive.

Images, UC QuakeStudies

A photograph of Graeme Kershaw, Technician at the University of Canterbury Department of Physics and Astronomy, sitting among the damaged parts of the Townsend Telescope. The telescope was damaged during the 22 February 2011 earthquake, when the Observatory tower at the Christchurch Arts Centre collapsed. Kershaw has been given the task of restoring the telescope. In this photograph he is holding the telescope's clock drive.

Articles, UC QuakeStudies

This report describes the earthquake hazard in Ashburton district and gives details of historic earthquakes. It includes district-scale (1:250,000) active fault, ground shaking zone, liquefaction and landslide susceptibility maps. The report describes earthquake scenarios for a magnitude 7.0-7.3 earthquake on the Mt Hutt-Mt Peel Fault Zone and a magnitude 8 Alpine Fault earthquake. See Object Overview for background and usage information.

Images, UC QuakeStudies

A photograph of Wesley Mauafu (PYLAT, right) receiving the Commitment to Wellbeing Award at the 2016 Youth Voice Canterbury Awards. This award was sponsored by All Right? and CDHB. Also pictured are other runners-up Petra Jellyman and Megan Crawley (left), award presenter Evon Currie (CDHB Population and Public Health General Manager, middle) and MC Riki Welsh (PYLAT, middle-right).

Videos, UC QuakeStudies

A video of a press conference with Canterbury Earthquake Recovery Minister Gerry Brownlee. Brownlee announced that cabinet has agreed to redevelop the hospital sites throughout Canterbury. This will include the building of additional operating theatres, the replacement of around 5000 beds, the expansion of the intensive care unit and emergency department, and the building of a new hospital for older persons in Burwood.

Articles, UC QuakeStudies

This report describes the earthquake hazard in Selwyn district and gives details of historic earthquakes. It includes district-scale (1:250,000) active fault, ground shaking zone, liquefaction and landslide susceptibility maps. The report describes earthquake scenarios for a magnitude 7.0-7.3 earthquake on the Porters Pass-Amberley Fault Zone and a magnitude 8 Alpine Fault earthquake. See Object Overview for background and usage information.

Articles, UC QuakeStudies

This report describes the earthquake hazard in Timaru district and gives details of historic earthquakes. It includes district-scale (1:250,000) active fault, ground shaking zone, liquefaction and landslide susceptibility maps. The report describes earthquake scenarios for a magnitude 7.0-7.3 earthquake on the Mt Hutt-Mt Peel Fault Zone and a magnitude 8 Alpine Fault earthquake. See Object Overview for background and usage information.

Videos, UC QuakeStudies

A video made by Julian Vares about FESTA - the Festival of Transitional Architecture. The video includes explanations from FESTA director Jessica Halliday and key collaborators about what FESTA is about, and the important role it plays in the rebuild and recovery of Christchurch. It also includes a compilation of footage from the first three FESTA events of 2012, 2013 and 2014. This footage was shot by Rick Harvie (Belmont Productions), Peter Young (Fisheye Films), Ed Lust and John Chrisstoffels.

Images, UC QuakeStudies

A poem written on Gap Filler and Poetica's "Instant Poetry" wall on Colombo Street. The poem reads, "Amidst the shards of glass and twisted steel, beside the fallen brick and scattered concrete, we began to understand that there is beauty in the broken. Strangers do not live here anymore". This poem was picked by the public as the favourite poem written on the wall. It was then painted permanently onto the mural.