title: Designing and developing stable body flight in drones

authors: Haisley, Sean

subjects: Aerodynamics

abstract: Drones are an ever-expanding field finding use and application in more and more area, such as construction, logging and transport. As a drone flies, it tilts its body in the direction of flight, however in some cases this tilting of the body is an undesired side effect of the drone’s movement and results in drones not being applied efficiently in such a field. Therefore, the question arises, “Can a drone be developed to allow for stable-bodied flight in order to provide a non-tilting platform for carrying payloads in the future?” The goal of this thesis is to find a solution to that question. By looking at drones that currently provide similar solutions, this thesis provides possible concept solutions and determines the best design for implementing this stable-bodied flight and then covers the components that would be required and the manufacturing process of such a drone. The analysis of the design show that drone designs with gimbal, whether it be the body or the propellers that are contained by the gimbals, allow for infinite degrees of freedom, which is useful in maintaining stable flight. Testing and design development, show that a drone where the propellers are gimbal rotated allows for the highest level of control, whereas turning the drone body into a gimbal, creates a simpler and aerodynamic design. Both designs are developed further, leading to the conclusion that the gimbal rotor drone is a more complex design, requiring machine learning to determine the optimal angles of attack and thrust for each of the propellers, in order to maintain stable flight. Due to this and the aerodynamic advantage of the gimbal body design, this drone is selected as a final design.

text: Designing and developing stable body flight in drones Drones are an ever-expanding field finding use and application in more and more area, such as construction, logging and transport. As a drone flies, it tilts its body in the direction of flight, however in some cases this tilting of the body is an undesired side effect of the drone’s movement and results in drones not being applied efficiently in such a field. Therefore, the question arises, “Can a drone be developed to allow for stable-bodied flight in order to provide a non-tilting platform for carrying payloads in the future?” The goal of this thesis is to find a solution to that question. By looking at drones that currently provide similar solutions, this thesis provides possible concept solutions and determines the best design for implementing this stable-bodied flight and then covers the components that would be required and the manufacturing process of such a drone. The analysis of the design show that drone designs with gimbal, whether it be the body or the propellers that are contained by the gimbals, allow for infinite degrees of freedom, which is useful in maintaining stable flight. Testing and design development, show that a drone where the propellers are gimbal rotated allows for the highest level of control, whereas turning the drone body into a gimbal, creates a simpler and aerodynamic design. Both designs are developed further, leading to the conclusion that the gimbal rotor drone is a more complex design, requiring machine learning to determine the optimal angles of attack and thrust for each of the propellers, in order to maintain stable flight. Due to this and the aerodynamic advantage of the gimbal body design, this drone is selected as a final design.

year: 2021

title: A comparison of different approaches for measuring denitrification rates in a nitrate removing bioreactor

authors: Warneke, Sören

subjects: Denitrification

abstract: Denitrifying woodchip bioreactors (denitrification beds) are increasingly used to remove excess nitrate (NO₃⁻) from point-sources such as wastewater effluent or subsurface drains from agricultural fields. NO₃⁻ removal in these beds is assumed to be due to microbial denitrification but direct measurements of denitrification are lacking. Our objective was to test four different approaches for measuring denitrification rates in a denitrification bed that treated effluent discharged from a glasshouse. We compared these denitrification rates with the rate of NO₃⁻ removal along the length of the bed. The NO₃⁻ removal rate was 8.73 ± 1.45 g m⁻³ d⁻¹. In vitro acetylene inhibition assays resulted in highly variable denitrification rates (DRAI) along the length of the bed and generally 5 times greater than the measured (NO₃⁻- N removal rate. An in situ push–pull test, where enriched ¹⁵N- NO₃⁻was injected into 2 locations along the bed, resulted in rates of 23.2 ± 1.43 g N m⁻³ d⁻¹ and 8.06 ± 1.64 g N m⁻³ d⁻¹. The denitrification rate calculated from the increase in dissolved N2 and N2O concentrations (DRN2) along the length of the denitrification bed was 6.7 ± 1.61 g N m⁻³ d⁻¹. Lastly, denitrification rates calculated from changes in natural abundance measurements of δ¹⁵N-N₂ and δ¹⁵N- NO₃⁻ along the length of the bed yielded a denitrification rate (DRNA) of 6.39 ± 2.07 g m⁻³ d⁻¹. Based on our experience, DRN2 measurements were the easiest and most efficient approach for determining the denitrification rate and N₂O production of a denitrification bed. However, the other approaches were useful for testing other hypotheses such as factors limiting denitrification or may be applied to determine denitrification rates in environmental systems different to our study site. DRN2 does require very careful sampling to avoid atmospheric N2 contamination but could be used to rapidly determine denitrification rates in a variety of aquatic systems with high N2 production and even water flows. These measurements demonstrated that the majority of NO₃⁻ removal was due to heterotrophic denitrification.

text: A comparison of different approaches for measuring denitrification rates in a nitrate removing bioreactor Denitrifying woodchip bioreactors (denitrification beds) are increasingly used to remove excess nitrate (NO₃⁻) from point-sources such as wastewater effluent or subsurface drains from agricultural fields. NO₃⁻ removal in these beds is assumed to be due to microbial denitrification but direct measurements of denitrification are lacking. Our objective was to test four different approaches for measuring denitrification rates in a denitrification bed that treated effluent discharged from a glasshouse. We compared these denitrification rates with the rate of NO₃⁻ removal along the length of the bed. The NO₃⁻ removal rate was 8.73 ± 1.45 g m⁻³ d⁻¹. In vitro acetylene inhibition assays resulted in highly variable denitrification rates (DRAI) along the length of the bed and generally 5 times greater than the measured (NO₃⁻- N removal rate. An in situ push–pull test, where enriched ¹⁵N- NO₃⁻was injected into 2 locations along the bed, resulted in rates of 23.2 ± 1.43 g N m⁻³ d⁻¹ and 8.06 ± 1.64 g N m⁻³ d⁻¹. The denitrification rate calculated from the increase in dissolved N2 and N2O concentrations (DRN2) along the length of the denitrification bed was 6.7 ± 1.61 g N m⁻³ d⁻¹. Lastly, denitrification rates calculated from changes in natural abundance measurements of δ¹⁵N-N₂ and δ¹⁵N- NO₃⁻ along the length of the bed yielded a denitrification rate (DRNA) of 6.39 ± 2.07 g m⁻³ d⁻¹. Based on our experience, DRN2 measurements were the easiest and most efficient approach for determining the denitrification rate and N₂O production of a denitrification bed. However, the other approaches were useful for testing other hypotheses such as factors limiting denitrification or may be applied to determine denitrification rates in environmental systems different to our study site. DRN2 does require very careful sampling to avoid atmospheric N2 contamination but could be used to rapidly determine denitrification rates in a variety of aquatic systems with high N2 production and even water flows. These measurements demonstrated that the majority of NO₃⁻ removal was due to heterotrophic denitrification.

year: 2011

title: Rethinking English in Māori-medium education

authors: Hill, Richard Kenneth

subjects: Māori-medium

abstract: English language instruction in New Zealand's Māori-medium schools is controversial, with many schools either excluding it from their curriculum or adopting a tokenistic approach. Yet, how Māori-medium educators can best support their students' academic English language growth is still an under-researched and unresolved question. This paper reports on a project involving the English language transition programmes of three Māori-medium primary schools. Interviews and observations of key personnel within these schools revealed the components of their programmes, their perceptions of the need for English transition education and the issues they were facing in implementing English language instruction. The project found a direct relationship between levels of student language attainment and the quantity and quality of exposure to English instruction. Where an English programme occupied a significant place in a school's timetable and was staffed by teachers knowledgeable about the learning needs of bilingual students and how best to attend to these, the result was higher literacy scores and more satisfied students. This paper argues that planning English language outcomes for Māori-medium students is essential if becoming biliterate is an important aim. This planning must also be long-term, across all 13 years of the students' education.

text: Rethinking English in Māori-medium education English language instruction in New Zealand's Māori-medium schools is controversial, with many schools either excluding it from their curriculum or adopting a tokenistic approach. Yet, how Māori-medium educators can best support their students' academic English language growth is still an under-researched and unresolved question. This paper reports on a project involving the English language transition programmes of three Māori-medium primary schools. Interviews and observations of key personnel within these schools revealed the components of their programmes, their perceptions of the need for English transition education and the issues they were facing in implementing English language instruction. The project found a direct relationship between levels of student language attainment and the quantity and quality of exposure to English instruction. Where an English programme occupied a significant place in a school's timetable and was staffed by teachers knowledgeable about the learning needs of bilingual students and how best to attend to these, the result was higher literacy scores and more satisfied students. This paper argues that planning English language outcomes for Māori-medium students is essential if becoming biliterate is an important aim. This planning must also be long-term, across all 13 years of the students' education.

year: 2011