title: Effect of amending cattle urine with dicyandiamide on soil nitrogen dynamics and leaching of urinary-nitrogen

authors: Welten, Brendon Grant

subjects: 15N isotope

abstract: Oral administration of dicyandiamide (DCD) to grazing ruminants for excretion in urine represents an alternative delivery technique to conventional broadcast application of DCD to reduce urinary nitrogen (N) losses from grazed pastures. A field lysimeter trial and an allied plot mowing trial were conducted to examine the effects of intermixing DCD in cattle urine on soil and pasture N dynamics and leaching losses in a free-draining pumice soil. DCD was either intermixed with urine to achieve equivalent application rates of 10, 30 or 60 kg DCD haˉ¹, or surface broadcasted as a spray solution (10 or 30 kg DCD haˉ¹) onto the soil surface following urine application and compared to controls (urine and nil-controls without DCD). A single application of  ¹⁵N-labelled artificial cattle urine (equivalent to 600 kg N haˉ¹) and corresponding DCD treatments were applied in late autumn and monitored over the following 300 days. DCD altered the partitioning of the applied urine-¹⁵N by increasing plant uptake of urinary-N by 32–60% and decreasing urine-¹⁵N in leachate, which was primarily influenced by the amount of DCD applied. The method of DCD application had no significant effect on leaching of any N constituent, except for ammonium-N, which was higher in the intermixed relative to the spray DCD treatments (26 vs. 18 kg N haˉ¹, respectively; P < 0.05). The total amount of nitrate-N leached was reduced from 217 kg N haˉ¹in the urine-control to 143, 80 and 61 kg N haˉ¹ (P < 0.05) with increasing rates of DCD application of 10, 30 and 60 kg haˉ¹, respectively. Application of DCD also significantly (P < 0.05) decreased the total amounts of ammonium-N and dissolved organic-N (DON) leached, but led to leaching losses of DCD-N. Rapid and large leaching losses of DCD down the soil profile led to spatial separation from the ammonium-N retained in the surface layer. Leaching of DCD (below 600 mm) at 55–69% of that applied represented an important leachable organic-N source (equivalent to 4–27 kg N haˉ¹), and reduced the overall efficacy of DCD in decreasing total N leaching losses. The total N leaching losses from all measured N fractions were 332 kg N haˉ¹ in the urine-control compared to 236, 157 and 154 kg N haˉ¹ at DCD application rates of 10, 30 and 60 kg haˉ¹, respectively. This study highlights the potential benefit from delivering DCD in cattle urine to reduce urinary-N leaching losses, with the most effective targeted single application rate being 30 kg haˉ¹ under the experimental conditions of this study.

text: Effect of amending cattle urine with dicyandiamide on soil nitrogen dynamics and leaching of urinary-nitrogen Oral administration of dicyandiamide (DCD) to grazing ruminants for excretion in urine represents an alternative delivery technique to conventional broadcast application of DCD to reduce urinary nitrogen (N) losses from grazed pastures. A field lysimeter trial and an allied plot mowing trial were conducted to examine the effects of intermixing DCD in cattle urine on soil and pasture N dynamics and leaching losses in a free-draining pumice soil. DCD was either intermixed with urine to achieve equivalent application rates of 10, 30 or 60 kg DCD haˉ¹, or surface broadcasted as a spray solution (10 or 30 kg DCD haˉ¹) onto the soil surface following urine application and compared to controls (urine and nil-controls without DCD). A single application of  ¹⁵N-labelled artificial cattle urine (equivalent to 600 kg N haˉ¹) and corresponding DCD treatments were applied in late autumn and monitored over the following 300 days. DCD altered the partitioning of the applied urine-¹⁵N by increasing plant uptake of urinary-N by 32–60% and decreasing urine-¹⁵N in leachate, which was primarily influenced by the amount of DCD applied. The method of DCD application had no significant effect on leaching of any N constituent, except for ammonium-N, which was higher in the intermixed relative to the spray DCD treatments (26 vs. 18 kg N haˉ¹, respectively; P < 0.05). The total amount of nitrate-N leached was reduced from 217 kg N haˉ¹in the urine-control to 143, 80 and 61 kg N haˉ¹ (P < 0.05) with increasing rates of DCD application of 10, 30 and 60 kg haˉ¹, respectively. Application of DCD also significantly (P < 0.05) decreased the total amounts of ammonium-N and dissolved organic-N (DON) leached, but led to leaching losses of DCD-N. Rapid and large leaching losses of DCD down the soil profile led to spatial separation from the ammonium-N retained in the surface layer. Leaching of DCD (below 600 mm) at 55–69% of that applied represented an important leachable organic-N source (equivalent to 4–27 kg N haˉ¹), and reduced the overall efficacy of DCD in decreasing total N leaching losses. The total N leaching losses from all measured N fractions were 332 kg N haˉ¹ in the urine-control compared to 236, 157 and 154 kg N haˉ¹ at DCD application rates of 10, 30 and 60 kg haˉ¹, respectively. This study highlights the potential benefit from delivering DCD in cattle urine to reduce urinary-N leaching losses, with the most effective targeted single application rate being 30 kg haˉ¹ under the experimental conditions of this study.

year: 2013

title: Design of twin foldable and tiltable rotors flight vehicle model

authors: Zhang, Ziqian

abstract: With the increasing number of private cars, traffic congestion is getting worse. Compared to the ground, there is a wider space in the sky due to its three-dimensional space. In consideration of this, flight vehicles would be one of the best ways to solve the traffic problem on the ground. 

A new concept of the structure for the flight vehicle has been presented in this thesis. It has two rotors with folding mechanisms to provide lift. The two rotors could be folded to reduce the size when it is in the car mode. Also because of the twin rotors design, the structure of the rotor head becomes simpler than usual helicopter main rotor head. Moreover, by using some gearboxes, it makes the flying car just using one motor to power the two rotors. The use of these gearboxes can also simplify the structure of the rotor head. Due to the research of this concept is in the initial stage, thus, the project just made a model, not a real flying car to verify the feasibility of the concept. What is more, a method to control the model has been shown in this thesis by using a normal controller. This thesis focuses on the process of making the flight vehicle model including calculation, mechanical design, implementation and control method.

text: Design of twin foldable and tiltable rotors flight vehicle model With the increasing number of private cars, traffic congestion is getting worse. Compared to the ground, there is a wider space in the sky due to its three-dimensional space. In consideration of this, flight vehicles would be one of the best ways to solve the traffic problem on the ground. 

A new concept of the structure for the flight vehicle has been presented in this thesis. It has two rotors with folding mechanisms to provide lift. The two rotors could be folded to reduce the size when it is in the car mode. Also because of the twin rotors design, the structure of the rotor head becomes simpler than usual helicopter main rotor head. Moreover, by using some gearboxes, it makes the flying car just using one motor to power the two rotors. The use of these gearboxes can also simplify the structure of the rotor head. Due to the research of this concept is in the initial stage, thus, the project just made a model, not a real flying car to verify the feasibility of the concept. What is more, a method to control the model has been shown in this thesis by using a normal controller. This thesis focuses on the process of making the flight vehicle model including calculation, mechanical design, implementation and control method.

year: 2017

title: Breaking the Barrier: Maori religious and spiritual entanglements at Aotea

authors: Klink, Kelly Moanna

subjects: Ngati Rehua

abstract: In 1889, Ngāti Rehua converted en masse to the Church of Jesus Christ of Latter Day Saints (LDS). This surprising conversion is remarkable for various reasons.  Māori across the country had not only converted to Christianity several decades earlier but by the late nineteenth century had already established their own religious denominations that renegotiated Judeao Christian teachings in new ways.  The proximity of Aotea to the Bay of Islands and their own converted kin on the mainland made this very late conversion all the more remarkable. This was the first time that any Christian organisation found any meaningful success with native peoples on the island, despite the widespread impact of Anglican, Catholic, Wesleyan, and Presbyterian missionaries throughout the region. With so many converted iwi at their doorstep, and the widespread influence of early missionaries and Māori agents of conversion, why did Ngāti Rehua take so long to convert to Christianity? While other iwi were converting in large numbers to Christianity or renegotiating Christianity on their own terms, Ngāti Rehua remained isolated and aloof for much of the nineteenth century, maintaining traditional beliefs and practices that had disappeared or been significantly modified in other tribal regions.  This thesis explores this question in three main chapters. Chapter One explores early Aotea history, beliefs and practices and examines how those on the island remained elusive from the onslaught of missionaries during the formative years of the establishment of Christianity.  Chapter Two highlights the many Aotea inter-tribal connections, the ongoing isolated history of Aotea and early missionary influences. Chapter Three turns its attention to the arrival of Mormon missionaries in 1889 and discusses the ‘moments’ of conversion that have been maintained in successive generations.

text: Breaking the Barrier: Maori religious and spiritual entanglements at Aotea In 1889, Ngāti Rehua converted en masse to the Church of Jesus Christ of Latter Day Saints (LDS). This surprising conversion is remarkable for various reasons.  Māori across the country had not only converted to Christianity several decades earlier but by the late nineteenth century had already established their own religious denominations that renegotiated Judeao Christian teachings in new ways.  The proximity of Aotea to the Bay of Islands and their own converted kin on the mainland made this very late conversion all the more remarkable. This was the first time that any Christian organisation found any meaningful success with native peoples on the island, despite the widespread impact of Anglican, Catholic, Wesleyan, and Presbyterian missionaries throughout the region. With so many converted iwi at their doorstep, and the widespread influence of early missionaries and Māori agents of conversion, why did Ngāti Rehua take so long to convert to Christianity? While other iwi were converting in large numbers to Christianity or renegotiating Christianity on their own terms, Ngāti Rehua remained isolated and aloof for much of the nineteenth century, maintaining traditional beliefs and practices that had disappeared or been significantly modified in other tribal regions.  This thesis explores this question in three main chapters. Chapter One explores early Aotea history, beliefs and practices and examines how those on the island remained elusive from the onslaught of missionaries during the formative years of the establishment of Christianity.  Chapter Two highlights the many Aotea inter-tribal connections, the ongoing isolated history of Aotea and early missionary influences. Chapter Three turns its attention to the arrival of Mormon missionaries in 1889 and discusses the ‘moments’ of conversion that have been maintained in successive generations.

year: 2019