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Fruit measurement horticultural device : developing trust through usability across complex systems : a thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy, College of Creative Arts / Toi Rauwhārangi, Massey University, Wellington, New Zealand
(Massey University, 2024-12-11) Krige, Zené
The agricultural technology (ag-tech) sector aims to use emerging technologies to meet changing consumer demands. To do this, the design of an intuitive smart object needed to be developed, and appraised for the horticultural industry of New Zealand. Its subsequent data needed to be expressed in tangible ways that empower decision-making about orchard operations. An elevated user experience of the device, along with quality data driving the system, would provide a successful engagement with an intelligent product system that sustains trust in the interaction and purpose of the product and integrates trust as a value within the system to advance resilience in horticultural innovation. Focusing on the task of fruit measurement, this project explores the conceptual design of a technology-driven device that can efficiently measure fruit size and count, throughout the season. The translation of this data in a format that enables stakeholders to analyse, query and act on it, seeks to inform and empower decision-making by the end users and stakeholders about the best time to harvest. This allows for better management of resources and deployment of labour and equipment. The consequence is a more sustainable orchard operation with greater productivity and benefits to all stakeholders. The project investigates the interrelationships between stakeholders, their equipment and orchard systems to drive product innovation by strengthening foundations of trust and utility, developing confidence in product use, and demonstrating its role in providing critical data into a horticultural management system with an inanimate object (product) placed within the orchard environment. This creative practice research project aims to address the opportunities that design can offer in bridging technological capability to usable products that can communicate trustworthy data clearly to end-users.
Novel visible light positioning techniques : a thesis presented in partial fulfilment of the requirements of the degree of Doctor of Philosophy in Department of Mechanical and Electrical Engineering at Massey University, Albany, New Zealand
(Massey University, 2024-01-31) Chew, Moi Tin
Localization is the process of finding an object’s position within the space that it is situated in. Localization can be categorised into two types, indoors and outdoors. Outdoor localization is already a matured technology which mainly relies on well-known positioning satellite systems such as Global Positioning System (GPS) and GLObal NAvigation Satellite System (GLONASS). However, the indoor localization is still a growing area of research. Visible Light Positioning (VLP) has been getting the attention of researchers due to several advantageous factors. VLP is more accurate than many of the competing techniques. As Light Emitting Diode (LED) based luminaires have become an integral part of the indoor lighting systems in modern buildings and residences, such lighting infrastructure can be leveraged for localizing objects. The VLP systems are also suitable in places like hospitals and airports due to the fact that LED does not generate electromagnetic interference which can potentially affect the operation of many equipment used in those places. This doctoral research develops novel techniques and applications for VLP, and these are fully supported by experimental results and data analysis. Fingerprinting is a common positioning method used in VLP systems that employs Received Signal Strength (RSS) as the signal characteristics. Weighted K-Nearest Neighbour (WKNN) is one of the most popular algorithms for such localization systems. This thesis investigates the impact of distance metrics used to compute the weights of the WKNN algorithm on the localization accuracy of the VLP. Experimental results show that Squared Chord distance is the most robust and accurate metric and significantly outperforms the commonly used Euclidean distance metric. Robot navigation is one of the many potential applications of VLP. Recent literature shows a small number of works on robots being controlled by fusing location information acquired by VLP that uses rolling shutter effect camera as a receiver with other sensor data. In contrast, this thesis reports the experimental performance of a cartesian robot that was controlled solely by a VLP system using a cheap photodiode-based receiver. Two different methods (Direct Method and Spring Relaxation Method) were developed to leverage the VLP as an online navigation system to control the robot. The experiments consisted of the robot autonomously repeating various paths multiple times. The results show that both methods offer promising accuracy, with Direct Method and Spring Relaxation Method reaching the target positions of median / 90-percentile error of 27.16mm / 37.04mm, and 26.05mm / 47.48mm respectively. The operation of VLP is very much dependent on the line of sight (LOS) link between the luminaires and the receiver. Unfortunately, in a practical environment, luminaires are positioned to serve illumination needs. Therefore, enough luminaires may not be visible for the purpose of positioning the target. One way to compensate this would be to utilise an ultrasound system to eliminate the “blind spots” of the VLP system. The final part of this work consists of a study of the ultrasound based indoor localization. A bespoke system employing an ultrasonic array to transmit chirp signals and time of flight measurement for ranging was developed. The position of the receiver is estimated iteratively using the spring relaxation technique. The spring relaxation technique, which has not been used for ultrasonic localization in the literature, outperforms the widely adopted linear least square-based lateration technique. The experimental results show that the ultrasonic system can be a viable option for fusing with a VLP system.
Towards zero carbon refurbishment of existing buildings in Aotearoa New Zealand : a decision support framework : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University, Albany, New Zealand
(Massey University, 2023) Bui, Thao Thi Phuong
Refurbishing the existing building stock is considered a fundamental element of reducing carbon emissions towards sustainable development. The renewal of the existing buildings is not only supposed to provide a better, healthier, more comfortable environment for people in which to live and work but also limit global warming, contributing to climate change mitigation. Due to existing buildings comprising the largest segment of New Zealand’s building stock, encouraging the low-carbon performance of existing buildings will contribute to achieve the net-zero carbon target by 2050. As a result, it is crucial to ensure that existing buildings are well-refurbished to reduce whole-of-life carbon emissions. Strategic decision-making in building refurbishment can increase building adaptability, durability, and resiliency, as well as achieve zero-carbon goals. However, it is complex and challenging as the consideration of lifecycle carbon performance must be integrated with other requirements, such as building regulations, client’s expectations, and stakeholders’ values. Before this thesis, limited research has explored the main factors and actors that affect decision-making in reducing carbon emissions and how to better make decarbonisation decisions for building refurbishment comprehensively. This thesis was undertaken to create a critical understanding of the decision-making process that incorporates carbon reduction initiatives in building refurbishment. This thesis aims to improve the decision-making towards zero carbon refurbishment of existing buildings in New Zealand. Following a sequence of multiple qualitative enquiry modes, a multi-method qualitative research design was applied to address the research aim, including literature review, preliminary study using semi-structured interviews, case studies and focus group discussions. Through examining the current practices of building refurbishment and the decision-making process for reducing whole-of-life carbon emissions in building refurbishment, a novel decision support framework towards zero carbon refurbishment of existing buildings in New Zealand was proposed as the main result of this thesis. Findings from this research have revealed that New Zealand’s building and construction industry is in the early stage of transiting to a net-zero carbon built environment, with many barriers to reducing carbon emissions in the design and construction of buildings, such as are financial issues, the shortage of knowledge, capacity and capability, the lack of legislation, and organisational culture barriers. Moreover, stakeholders involved in building refurbishment have faced many challenges in integrating carbon reduction in their decision-making practices in different areas of the pre-design and design stages of the refurbishment process, including (1) inexplicit carbon goal setting, (2) ineffective building condition assessment, (3) deficient and incomprehensive relevant whole-of-life carbon information to support the decision-making, and (4) inconsistent and ambiguous carbon-calculation guidelines and benchmark. The results also emphasise that considering both embodied and operational carbon impacts is critical to maximising carbon reduction in a building throughout its life cycle. Especially, for building refurbishment, the priority should move from reducing operational to whole-of-life carbon emissions. The results from this thesis also provide an in-depth understanding of the characteristics of the decision-making process in practice, lessons learnt for improved implementation of building refurbishment and the effectiveness of collaborative rationality among the diverse stakeholders. Based on theoretical propositions found in the literature and practical knowledge from empirical findings, a comprehensive decision support framework was developed that provides a detailed guideline to better-delivering building refurbishment towards zero carbon. The framework supports the stakeholders involved in building refurbishment to understand the refurbishment decision-making process and requirements for reducing carbon emissions in certain activities, identify areas for addressing carbon issues in the early stages of the refurbishment process, determine relevant information key factors and actors in driving carbon-reduction solutions, and promote stakeholder collaboration and integration in carbon-reduction building refurbishment. This thesis updates both the practical and theoretical understanding of challenges and improvement measures to establish a greater way to support decarbonisation decisions for building refurbishment. The decision-support framework from this thesis offers building stakeholders a more holistic and streamlined interdisciplinary guide to recognise the decarbonisation decision with its required information, expertise, and mechanisms to reduce carbon emissions for the refurbished building throughout the decision-making process in practice. Findings from this thesis are also of relevance to the theoretical and practical knowledge of how the decisions are made to maximise carbon reduction in building refurbishment as a guide for other researchers who are pursuing closely related research topics to that of this thesis.
Improving the quality of dried Theobroma cacao beans using a solar assisted desiccant-based dryer : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Palmerston North, New Zealand
(Massey University, 2023) Raju, Rupantri Nandika
"Theobroma cacao" beans are an economically significant commodity for the Fiji Islands. The cocoa beans are harvested in the wild and then fermented and sun-dried under tropical weather conditions. The high relative humidity (RH) as well as the unpredictable weather conditions extend the sun-drying time and causes quality issues in the final dried product. Maintaining product quality is important as export quality cocoa beans are sold at premium prices to chocolate manufacturers internationally. The problems in sun-dying can be solved by reducing the RH of drying air stream. This is possible with desiccant wheel technology (DWT). The solid desiccant material in DWT desorbs moisture from air and reduces humidity. The desiccant material can be regeneration between 60 and 100 °C for the next cycle. This temperature conditions can be achieved by using a solar dryer. This study tested the drying conditions below 20% RH on small batches (6 kg) of fermented Fijian cocoa beans at 45 °C and 55 °C. Impact of these conditions on the drying kinetics and bioactive quality was tested. Experimental data was used to validate a mechanistic drying model. The model was developed using partial differential equations (PDEs) with an implicit scheme for a targeted drying time of 72 hours. Finite difference method (FDM) was used to solve PDEs. The model output was comparable to experimental data from drying runs in Fiji. Reducing the RH at 45 °C showed a better retention of key bioactive compounds, such as polyphenols, caffeine, and theobromine when compared to other treatments. These findings are presented in detail in this thesis and suggests that DWT can provide consistent drying conditions in a tropical environment. The drying model is a useful tool for predicting the drying conditions for cocoa beans based on multiple input variables. The model can be used to advise cocoa farmers on the estimated processing time for cocoa beans to meet the demands of the export market.
Design and fabrication of a climate-controlled lysimeter and testing of new controlled-release fertilisers : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy (PHD) in Agricultural Engineering and Environmental Sciences at Massey University, Palmerston North, New Zealand
(Massey University, 2021) Gunaratnam, Abhiram
Pastoral agriculture is the backbone of the New Zealand (NZ) economy and nearly 9 million hectares of land (33% of the total land area in NZ) is under pastoral farming. The higher and continuous applications of readily available N fertilisers to pastoral land use increase nitrogen (N) losses, which degrade the water and air quality. Controlled-release fertilisers (CRFs) have been shown to be an effective strategy to mitigate N losses in many parts of the world. This study was undertaken to develop different CRF formulations and test their effect on ryegrass under a simulated climate condition. A new controlled-environment lysimeter system was designed and fabricated, since lysimeter designs available in the literature are not suitable to conduct a controlled-environment study. The lysimeter was permanently capped to provide a confined space for controlling the microclimate of ryegrass, and equipped with sensors to monitor the environmental variables. An environmental controlling unit (ECU) was designed to emulate a climate model and control the environmental variables in the lysimeter. Taranaki region’s (spring season of the year 2013) climate model was selected to emulate in this design. The ECU modifies the ambient air according to the climate model and circulates it through 40 lysimeters using air conduits and distributors. The ryegrass was grown for three months under simulated climate conditions, and DM yield was measured. In addition, microclimate temperature, relative humidity (RH), evapotranspiration and drainage of each lysimeter during the experimental period were recorded. The performance of the ECU was tested by comparing the observed temperature and RH values of the plant proximity with setpoints of the climate model. In addition, the performance of the lysimeter system on recreating the climate model was tested by comparing the observed drainage, evapotranspiration, and DM yield values with the estimated values derived from the climate model. The root-mean-square error (RMSE) of temperature was 1.96 °C day⁻¹, which was marginally higher than the targeted temperature variation range of 1 °C day⁻¹. However, the RMSE of RH was 4.45% day⁻¹, which was within the targeted fluctuation range of 5% day⁻¹. These observations showed that the ECU satisfactorily controlled the environmental variables as per the climate model. The observed drainage, evapotranspiration and total DM yield were within the estimated values; 525 mm, 104 mm and 2167 kg-DM ha⁻¹, respectively. These results revealed that the selected Taranaki climate model was successfully emulated in the newly developed lysimeter system design. A low-cost, simple lysimeter soil retriever (LSR) design was fabricated to retrieve the soil, and its performance was examined. The soil moisture influenced the retrieval process, where lower disturbances for soil block structure and roots were observed for soil with high moisture (28%) than low moisture (13%). The linear actuator used in this design was powerful enough to perform soil retrieval and showed consistent performance after 80 soil columns were retrieved. Force given by the linear actuator did not damage the lysimeter body, but was sufficient to push the soil column out of the lysimeter. Therefore, this design is suitable to retrieve soil blocks from mini (<100 kg) and small (100-1000 kg) lysimeters. Different forms of CRFs were developed by coating urea with epoxy-lignite (Epox) or polyester-lignite (Poly) polymer composites. Each composite was coated three or five times, and therefore four CRFs were formulated depending on the type of composite and coating thickness; Epox3, Epox5, Poly3, and Poly5. The complete release of urea took place at 144, 408, 120 and 175 hours for Epox3, Epox5, Poly3 and Poly5, respectively, in water. Increasing the coating thickness prolonged the duration of urea release for both composites. Although no cracks were identified in all the CRF coatings, micropores were seen under high magnification in the scanning electron microscopy (SEM) images. The interactions between lignite and polymer were demonstrated using Fourier Transform Infrared Spectroscopy (FTIR) analysis. The lignite dominated in all coatings compared to the polymer, and lignite compositions were 2.1 to 5.3-fold higher than polymers in CRFs. The Epox5 showed overall better performance than other formulations. The CRF formulations which showed more controlled-release characteristics in water; Epox5 and Poly5, were selected to study their performance on ryegrass against urea and diammonium phosphate (DAP) in the climate-controlled lysimeter system. The total DM yield, root DM distribution, herbage N recovery and nitrogen utilisation efficiencies (NUE) were not significantly different between N treatments. Although N₂O emission and nitrate leaching losses were not significantly different between N treatments, the values were very low in comparison to the values obtained in similar studies reported in the literature. An investigation was carried out to find out the reason for these observed low N₂O and nitrate levels with different hypotheses. The only hypothesis tested that showed a significant relationship with these observed results; the high iron content of sand could have decreased the nitrate in leachate and N₂O emission. In this study, a 2 x 4 factorial design was used with two types of sand (low and high iron sand) and four N levels (0, 50, 100 and 200 kg-N ha⁻¹). It was found that high iron sand significantly lowered (P<0.05) the nitrate leaching at all N levels compared to low iron sand, except for the 0 kg-N ha⁻¹ treatment. The N2O emission was significantly lower (P<0.05) for high iron sand than low iron sand, only at the 200 kg-N ha⁻¹ application level. These observations support the hypothesis, that iron is involved in nitrate reduction and the possible mechanism was dissimilatory nitrate reduction (DNR) pathway. A new controlled-release fertiliser (Ver-1) was developed by Verum Group Ltd using lignite and urea. In this study, the effectiveness of two different types of CRFs (Epox5 and Ver-1) and two levels of iron application (239 and 478 kg-FeSO4 ha-1) on controlling N losses were tested in lysimeters where ryegrass was grown. The Epox5 and Ver-1 significantly (P<0.05) reduced N leaching losses by 37% and 47%, respectively, whereas only Epox5 significantly (P<0.05) increased N₂O emission compared to the urea treatment. Iron treatments were not effective in controlling N losses, which suggests that the expected DNR pathway was not prominent in this study. The DM yield and NUE were not significantly increased by CRFs and iron applications compared to the urea treatment. The hierarchical clustering analysis revealed that Ver-1 was the best treatment for controlling N leaching losses. Future research is recommended to investigate (a) the mechanism which underlies the reduction of nitrate in high iron content sand, (b) the effectiveness of iron application on N leaching losses on different soils, and (c) the performance of new CRFs formulations (Epox5 and Ver-1) at the field level.
Design of a novel X-section architecture for FX-correlator in large interferometers : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Engineering at Massey University, Auckland, New Zealand
(Massey University, 2021) Balu, Vignesh Raja
In large radio-interferometers it is considerably challenging to perform signal correlations at input data-rates of over 11 Tbps, which involves vast amount of storage, memory bandwidth and computational hardware. The primary objective of this research work is to focus on reducing the memory-access and design complexity in matrix architectural Big Data processing of the complex X-section of an FX-correlator employed in large array radio-telescopes. This thesis presents a dedicated correlator-system-multiplier-and -accumulator (CoSMAC) cell architecture based on the real input samples from antenna arrays which produces two 16-bit complex multiplications in the same clock cycle. The novel correlator cell optimization is achieved by utilizing the flipped mirror relationship between Discrete Fourier transform (DFT) samples owing to the symmetry and periodicity of the DFT coefficient vectors. The proposed CoSMAC structure is extended to build a new processing element (PE) which calculates both cross- correlation visibilities and auto-correlation functions simultaneously. Further, a novel mathematical model and a hardware design is derived to calculate two visibilities per baseline for the Quadrature signals (IQ sampled signals, where I is In-phase signal and Q is the 90 degrees phase shifted signal) named as Processing Element for IQ sampled signals (PE_IQ). These three proposed dedicated correlator cells minimise the number of visibility calculations in a baseline. The design methodology also targets the optimisation of the multiplier size in order to reduce the power and area further in the CoSMAC, PE and PE_IQ. Various fast and efficient multiplier algorithms are compared and combined to achieve a novel multiplier named Modified-Booth-Wallace-Multiplier and implemented in the CoSMAC and PE cells. The dedicated multiplier is designed to mostly target the area and power optimisations without degrading the performance. The conventional complex-multiplier-and-accumulators (CMACs) employed to perform the complex multiplications are replaced with these dedicated ASIC correlator cells along with the optimized multipliers to reduce the overall power and area requirements in a matrix correlator architecture. The proposed architecture lowers the number of ASIC processor cells required to calculate the overall baselines in an interferometer by eliminating the redundant cells. Hence the new matrix architectural minimization is very effective in reducing the hardware complexity by nearly 50% without affecting the overall speed and performance of very large interferometers like the Square Kilometre Array (SKA).
Learning-based robotic manipulation for dynamic object handling : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Mechatronic Engineering at the School of Food and Advanced Technology, Massey University, Turitea Campus, Palmerston North, New Zealand
(Massey University, 2021) Janse van Vuuren, Jacobus Petrus
Recent trends have shown that the lifecycles and production volumes of modern products are shortening. Consequently, many manufacturers subject to frequent change prefer flexible and reconfigurable production systems. Such schemes are often achieved by means of manual assembly, as conventional automated systems are perceived as lacking flexibility. Production lines that incorporate human workers are particularly common within consumer electronics and small appliances. Artificial intelligence (AI) is a possible avenue to achieve smart robotic automation in this context. In this research it is argued that a robust, autonomous object handling process plays a crucial role in future manufacturing systems that incorporate robotics—key to further closing the gap between manual and fully automated production. Novel object grasping is a difficult task, confounded by many factors including object geometry, weight distribution, friction coefficients and deformation characteristics. Sensing and actuation accuracy can also significantly impact manipulation quality. Another challenge is understanding the relationship between these factors, a specific grasping strategy, the robotic arm and the employed end-effector. Manipulation has been a central research topic within robotics for many years. Some works focus on design, i.e. specifying a gripper-object interface such that the effects of imprecise gripper placement and other confounding control-related factors are mitigated. Many universal robotic gripper designs have been considered, including 3-fingered gripper designs, anthropomorphic grippers, granular jamming end-effectors and underactuated mechanisms. While such approaches have maintained some interest, contemporary works predominantly utilise machine learning in conjunction with imaging technologies and generic force-closure end-effectors. Neural networks that utilise supervised and unsupervised learning schemes with an RGB or RGB-D input make up the bulk of publications within this field. Though many solutions have been studied, automatically generating a robust grasp configuration for objects not known a priori, remains an open-ended problem. An element of this issue relates to a lack of objective performance metrics to quantify the effectiveness of a solution—which has traditionally driven the direction of community focus by highlighting gaps in the state-of-the-art. This research employs monocular vision and deep learning to generate—and select from—a set of hypothesis grasps. A significant portion of this research relates to the process by which a final grasp is selected. Grasp synthesis is achieved by sampling the workspace using convolutional neural networks trained to recognise prospective grasp areas. Each potential pose is evaluated by the proposed method in conjunction with other input modalities—such as load-cells and an alternate perspective. To overcome human bias and build upon traditional metrics, scores are established to objectively quantify the quality of an executed grasp trial. Learning frameworks that aim to maximise for these scores are employed in the selection process to improve performance. The proposed methodology and associated metrics are empirically evaluated. A physical prototype system was constructed, employing a Dobot Magician robotic manipulator, vision enclosure, imaging system, conveyor, sensing unit and control system. Over 4,000 trials were conducted utilising 100 objects. Experimentation showed that robotic manipulation quality could be improved by 10.3% when selecting to optimise for the proposed metrics—quantified by a metric related to translational error. Trials further demonstrated a grasp success rate of 99.3% for known objects and 98.9% for objects for which a priori information is unavailable. For unknown objects, this equated to an improvement of approximately 10% relative to other similar methodologies in literature. A 5.3% reduction in grasp rate was observed when removing the metrics as selection criteria for the prototype system. The system operated at approximately 1 Hz when contemporary hardware was employed. Experimentation demonstrated that selecting a grasp pose based on the proposed metrics improved grasp rates by up to 4.6% for known objects and 2.5% for unknown objects—compared to selecting for grasp rate alone. This project was sponsored by the Richard and Mary Earle Technology Trust, the Ken and Elizabeth Powell Bursary and the Massey University Foundation. Without the financial support provided by these entities, it would not have been possible to construct the physical robotic system used for testing and experimentation. This research adds to the field of robotic manipulation, contributing to topics on grasp-induced error analysis, post-grasp error minimisation, grasp synthesis framework design and general grasp synthesis. Three journal publications and one IEEE Xplore paper have been published as a result of this research.
Automated 3D weaving continuous natural fibre and optimising harakeke fibre characterisation : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Mechatronics at Massey University, Albany, New Zealand
(Massey University, 2019) Lin, Junyi
This research investigated the design and implementation of a continuous natural fibre filament winding robot for modern artistic and structural architectural design. The idea of a new architectural construction technique based on Arduino integration was inspired by the underwater nesting structure of water spiders. It consists of the motion component, a 3-axis sliding table with limit switches, the construction of the machine, the programming and testing of the resulting microcomputer software through to a robot manufacturing process. This was based on Arduino’s new integrated development environment. In addition, the intelligent programming mode forms the preconceived pattern through winding, producing a model with unique architectural quality, and at the same time, making a structure with superior material efficiency. In terms of hardware design, the first conceptual model focused on using an open-source integrated development environment (IDE) that could be easily configured. Arduino hardware was the primary microcontroller of choice for simplicity and ease of hardware integration and software development. Stepper motor drivers are used to control the three stepper motors to accurately move the fibre feeding mechanism on the sliding table into position. The path of the sliding table is controlled by the controller, and the machine can make forward, backward, wire feed and other movements according to the programmed commands. The developed system automatically weaves and feeds natural fibre into the desired structure. The resulting lightweight natural fibre material forms a model with unique architectural quality. The results show that the model is of great value and significance, and it can be used to make the required structure with the desired natural fibre. Additionally, to establish the feasibility of future work focusing on harakeke fibre development in design and construction, the tensile strength of native New Zealand flax fibre (harakeke fibre) was evaluated with a view for use in these load bearing and architectural design applications. Single filament fibres were selected in batches and tensile tested. The longitudinal strength of specimens was established, and the mechanical properties of the fibres were summarised. Comparison of these attributes with existing data was used to determine if the harakeke fibre can be applied usefully in the construction industry. This research is based on the novel concept of architectural design in the construction industry using 3D weaving with natural fibres, in particular harakeke fibres. To achieve this, several related topics are under investigation, such as the need to design an improved feeding system (including hardware and software control), impregnation of fibre and resin (epoxy and polyester) to make preimpregnated (prepreg) fibre/resin filament, adaptive controlled programme and hardware for the required architecture and structure, and properties testing and characterisation. This project is one of the first attempts to develop an automated robot arm system combined with new material, in this case harakeke fibre, and has made a valuable contribution to this field of research.
The development of feedstock for 3D printing and 3D knitting of continuous carbon fibre composite filaments : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Mechatronics at Massey University, Albany, New Zealand
(Massey University, 2019) Kvalsvig, Andrew D.
The main purpose of this research was the development of a composite filament comprising of a thermoset resin and long/continuous carbon fibre reinforcement for the use with additive manufacturing applications. Currently, there are composite materials available that consist of fibre reinforcement but none that utilise long/continuous fibre reinforcement with a thermoset resin in a controlled manner. A series of prototypes were developed to determine the production processes required to produce the composite filament. Specimens were produced from these prototypes were subjected to cross-sectional analysis to analyse the quality of composite filament being produced. The results from this research is a production method that consistently produces the composite filament with the desired material properties. The secondary purpose of this research was to analyse a commercially available 3D printer, the Mark One, that can produce composite parts using long/continuous fibre reinforcement and a thermoplastic matrix. An analysis into the capabilities and limitations of the Mark One was conducted prior to analysing specimens produced by the Mark One. An analysis of the tensile properties of parts produced by the Mark One was conducted using fibreglass and carbon fibre long/continuous fibre reinforcement. Tensile specimens made in accordance with the standard ASTM D638 for Type I specimens were produced and tensile tested. The Taguchi method was used to analyse the effect and contribution that three parameters had on the tensile properties of specimens. Complications with specimens fracturing incorrectly lead to a redesign of the tensile specimens to ensure the specimens would fracture correctly. Several design iterations were tested until a final design was chosen. This final design was used for both fibreglass and carbon fibre specimens. The results from the tensile specimens showed the effect that changing certain parameters had on the tensile properties and the contribution that each parameter had on the tensile properties produced using the Mark One. These results were confirmed by producing tensile specimens using the optimal combination of parameters and provided insight into the capabilities of the Mark One.
A portable multi-modal micro-imaging system for automated scanning and image stitching applications : a thesis submitted to Massey University in accordance with the requirements of the degree of Master of Engineering in the School of Engineering and Advanced Technology
(Massey University, 2019) Naqvi, Adam
Microscopic imaging is an important element in many ﬁelds like biology, medicine, diagnostics, engineering, and materials research. Muti-modal microscopes are ideal for imaging samples that reveal unseen structures that could not otherwise be seen with normal bright-ﬁeld microscopes. Point-of-care micro-imaging devices are ones that can deliver the features of a microscope in areas where access to a laboratory or medical facilities are scarce. This thesis presents the development of a portable micro-imaging system that uses multi-modal illumination to image samples in bright-ﬁeld, ﬂuorescence, ambient and laser diffraction modes. A systematic design method has been used to develop the system from the conceptual phase to a working prototype. The system incorporates variable magniﬁcation through an inverted turret system and a GUI application for live image view, automatic scanning, auto-focusing and image processing. The utility of the system is demonstrated through imaging stained biological samples for a local industry application. The acquired images are measured against sharpness and noise. It is observed that the sharpness and noise of the images produced vary with the type of sample: samples with higher contrast generally produce sharper images with less noise. It has also been found that diffused ambient illumination produces the most consistent sharpness and noise scores between magniﬁcations. Performance of algorithms used is discussed and improvements are suggested for building a more compact and stable platform including a method to calibrate measurements for particle size estimation.

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