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    Design of attitude determination and control system for KIWISAT amateur satellite : a thesis presented in partial fulfillment of the requirements for the degree of Masters of Engineering, Mechatronics, at Massey University, Albany, Auckland, New Zealand
    (Massey University, 2015) Makarov, Kirill
    This thesis is to present the design of “ADAC” system for “KiwiSat” cube satellite. An array of sensors were used: CMOS low resolution camera, sun sensor, earth horizon sensors, 3 axis magnetometer. The control of satellite rely on magnetic coils installed orthogonally to each other. Implementation of this system is essential to achieve the full control of the satellite when it reaches the lower orbit. Solution for the pitfall such as: the lack of torque of the satellite when it’s parallel to the earth magnetic field, was also designed. Attitude estimation is nonlinear due of kinematics and the reading of above sensors. Both a proportional-derivative controller and a linear quadratic regulator are implemented for control model of the system. And the Floquet Theory is used to check the stability of the controls, and an optimization method further optimizes the results. Model was constructed by simulink program that was packaged with mathematical software called “Matlab”. 3D model of the satellite was drawn in SolidWorks for the purpose of visual interaction and behavior.
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    Development and applications of a low-field portable NMR system : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Physics at Massey University, Manawatu, New Zealand
    (Massey University, 2011) Ward, Robert L
    Nuclear magnetic resonance (NMR) is a phenomenon similar to MRI in which radio frequency signals are used to excite and manipulate atomic nuclei within a static magnetic field. Following excitation, the nuclei return to equilibrium, all the while offering valuable molecular level information pertaining to the sample. Within the last decade, the development of small and inexpensive NMR spectrometers and permanent magnet NMR sensors has been a significant focus within the NMR community. More recently, application scientists have sought practical applications for the new technologies. In this thesis, a prototype NMR apparatus consisting of a spectrometer and 3.2MHz permanent magnet sensor was extended to enable scientifc measurements. This involved developing radio frequency electronic circuitry for the spectrometer front-end, and electromagnetic noise shielding and temperature regulation for the magnetic sensor. Experimental results confirmed that repeatable measurements using the modified apparatus were indeed possible. The NMR apparatus was thereafter successfully used to study flow, diffusion and kiwifruit using several different experimental techniques. A significantly larger effort was then expended upon the study of T2 relaxation in pectin model systems using pH as the adjustable parameter. The fascinating experimental results were successfully interpreted and modeled across three pH zones in terms of a proton chemical exchange model and molecular conformational changes. In addition, it was found that pectin carboxyl de-protonation was significantly less than expected. Further experiments performed upon galacturonic acid monomers, dimers and trimers appeared to further illuminate the pectin results. Future experiments are planned. Also while studying pectin solutions, an unexpected pH-dependent water transverse relaxation behavior was observed at both 3.2MHz and 400MHz. The only references found in the literature were from a small publication almost 50 years ago, and a 2011 publication. Altogether, this thesis contributed to original knowledge in several ways: it showed how a low- eld apparatus and single-sided sensor could be improved and utilized for a variety of scientific measurements; it showed both experimentally and theoretically how T2 for pectin solutions change with pH; it revealed an unexpected de-protonation limit for pectin molecules; it revealed a T2 pH dependence for water.
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    Planar electromagmentic sensors for environmental monitoring : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Electricical Engineering at Massey University, Palmerston North, New Zealand
    (Massey University, 2011) Yunus, Mohd Amri bin Md
    Water is the essence of life and an important nutrient for every living thing. Therefore, ninety six novel planar electromagnetic sensors based on the combination of meander sensor and interdigital sensor have been designed, fabricated, and tested for the application of water quality monitoring. Experiments were conducted to obtain the impedance characterization for each sensor, and the results were used to estimate the important parameters that influence the performance of the sensors based on the equivalent electrical circuits. The best sensors were selected based on the design with the highest electrical parameters (total effective capacitance and effective inductance). Intensive modelling and simulation of the selected best sensors are also discussed where the results were compared with the simulation results. Furthermore, the best sensors have been tested to detect nitrates contamination in distilled water using sodium nitrate (NaNO3) and ammonium nitrate (NH4NO3) solutions with different concentrations. The sensor that consists of the series combinations of spiral meander planar sensor (with five turns) with the interdigital sensor (with large negative electrode): SECS22_1 is the best sensor to detect the presence of nitrate added into distilled water and can estimate the concentration level. Furthermore, the sensor was tested with various kinds of prepared samples and natural water samples taken from natural sources around New Zealand. The outcomes have shown a very good correlation of contamination level, translated from the qualitative and quantitative results. Using the SECS22_1 sensor, a method to estimate nitrate contamination in natural water sources using Independent Component Analysis (ICA) has been explained and demonstrated. This model can accurately estimate nitrate in a natural water source as shown by the results. A low-cost system has been developed based on SECS22_1, a microcontroller, a waveform circuit, signal conditioning circuits, and LabView. The results from the experiment have shown the low-cost system has the potential to be used as a tool for nitrate detection and water sources quality monitoring in remote places such as farms. Finally, the work and improvement for future consideration are also discussed in this research.