Du, Xiaona. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 65-74). / Abstracts in English and Chinese. / ABSTRACT --- p.i / 摘要 --- p.iii / ACKNOWLEDGEMENTS --- p.iii / TABLE OF CONTENTS --- p.iv / LIST OF FIGURES --- p.xi / LIST OF TABLES --- p.ix / Chapter CHAPTER ONE --- INTRODUCTION --- p.1 / Chapter 1.1 --- Background --- p.2 / Chapter 1.1.1 --- Development of portable devices --- p.2 / Chapter 1.1.2 --- Energy harvesting --- p.2 / Chapter 1.1.3 --- Piezoelectric energy harvesting --- p.5 / Chapter 1.1.4 --- Impact based piezoelectric energy harvester --- p.10 / Chapter 1.1.5 --- Operation of piezoelectric materials --- p.14 / Chapter 1.2 --- Research Objective --- p.16 / Chapter 1.3 --- Thesis Organization --- p.19 / Chapter CHAPTER TWO --- DESIGN AND MODELING OF AN EXTENDED ROTARY ENERGY HARVESTER --- p.20 / Chapter 2.1 --- Design Considerations of an Extended Rotary Energy Harvester --- p.20 / Chapter 2.2 --- Models of Rotary Energy Harvesters --- p.24 / Chapter 2.3 --- Simulation Results --- p.33 / Chapter 2.4 --- Chapter Summary --- p.37 / Chapter CHAPTER THREE --- "PROTOTYPE, TESTING AND OUTPUT POWER OF EXTENDED ROTARY ENERGY HARVESTER" --- p.38 / Chapter 3.1 --- Prototype and Experiment --- p.38 / Chapter 3.2 --- Output Power --- p.44 / Chapter 3.2.1 --- Maximum tip displacement on output power --- p.44 / Chapter 3.2.2 --- Rotational frequency on output power --- p.47 / Chapter 3.3 --- Chapter Summary --- p.50 / Chapter CHAPTER FOUR --- COMPARISON BETWEEN E-REH AND REH --- p.51 / Chapter 4.1 --- Force on Output Power --- p.52 / Chapter 4.2 --- Rotational Frequency on Output Power --- p.54 / Chapter 4.3 --- Comparison on Design Space --- p.59 / Chapter 4.4 --- Chapter Summary --- p.62 / Chapter CHAPTER FIVE --- CONCLUSION AND FUTURE WORK --- p.63 / Chapter 5.1 --- Conclusion --- p.63 / Chapter 5.2 --- Future Work --- p.64 / BIBLIOGRAPHY --- p.65

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Many seedsmen have observed that lima bean seed of a variety like Early Thorogreen, which has green cotyledons, often fades in color during harvesting. This fading of color is known as bleaching. A variety which has green cotyledon and hence green seed, should retain this green color during harvest. Bleached seeds are likely to emerge slowly when planted. Also, the final field stand from a planting of bleached seed is likely to be poor.

This work aims to demonstrate the design and simulation of a Radio Frequency (RF) energy-harvesting circuit, from receiving antenna to the point of charge collection. The circuit employs a custom-designed antenna based around Koch fractal loops, selected for their small physical size, good multiband behaviour and ease of size scalability, as well as a power-efficient seven-element Greinacher rectification section designed to charge a super-capacitor or rechargeable battery for later use. Multiple frequency bands are tapped for energy and this aspect of the implementation was one on the main focus points. The bands targeted for harvesting in this thesis will be those that are the most readily available to the general Canadian population. These include Wi-Fi hotspots (and other 2.4GHz sources), as well as cellular (850MHz band), Personal Communications Services (1900MHz band) and WiMax (2.3GHz) network transmitters.

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Electrocoagulation was compared to centrifugation at pilot scale for harvesting Nannochloris oculata and Nannochloropsis salina for biodiesel production. The pilot scale testing is a proof of concept and no optimization was conducted. Testing used the KASELCO commercial electrocoagulation system. The KASELCO electrocoagulation system successfully coagulated microalgae in laboratory testing. Aluminum and stainless steel electrodes successfully recovered algae in laboratory testing. Electricity consumed was lowest using aluminum electrodes in laboratory testing, but inconsistently coagulated microalgae at the pilot scale. Stainless steel electrodes consistently recovered algae and were selected as the primary electrode to treat microalgae at the pilot scale. Scaling power settings to pilot testing using laboratory data was successful following KASELCO’s proprietary guidelines. The KASELCO electrocoagulation system showed an electrical reduction in pilot scale operational cost for harvesting. Economic analysis using the Algae Income Simulation Model concluded that the KASELCO electrocoagulation system increase net present value of a commercial algae farm by $56,139,609 using a discount factor of 0.04. The KASELCO electrocoagulation system was calculated to use 26 kWh/ton at a commercial algae farm. However, cultivation and extraction processes are energy intensive, resulting in minimal electrical savings for the algae farm. The increase in net present value reduced production costs at the algae farm by 1%. The probability of success for the microalgae farm was zero for all scenarios analyzed. While a reduction in capital and operational costs were observed, several improvements, including harvesting using electrocoagulation, in cultivation, extraction, and conversion are necessary for economic success for biodiesel production using algae farms.

The demand for portable permanent sources of electrical energy increases every day to power portable or non-accessible devices. Energy harvesting from vibrations offers a non-traditional source of energy. It is renewable and prevailing, since nature around is rich in kinetic energy that can be harvested. In this work, we have developed two mechanisms to harvest energy from low-frequency vibrations present in nature using electromagnetic transduction. The harvesting mechanisms use a mass-on-spring mechanical oscillator to capture kinetic energy from a host body. Prototypes embodying the two harvesting mechanisms were fabricated and tested. We identi ed the system parameters of the harvester prototypes and generated their frequency-response curves. We analyzed the results using and compared them with mathematical models of the system dynamics to characterize the harvesters' performance including their output power, center frequency, and harvesting bandwidth. We were successful in demonstrating energy harvesters that can harvest low-frequency vibration with center frequencies in the range of 8-14 Hz, harvesting bandwidth in the range of 8-12Hz, and output power on the order of 1mW. The realized harvesters are relatively small, a few inches in dimension, and light, a few tens of grams in mass. We also introduced a novel electromagnetic transduction mechanism that can be used in harvesting low-frequency vibrations.

This work aims to demonstrate the design and simulation of a Radio Frequency (RF) energy-harvesting circuit, from receiving antenna to the point of charge collection. The circuit employs a custom-designed antenna based around Koch fractal loops, selected for their small physical size, good multiband behaviour and ease of size scalability, as well as a power-efficient seven-element Greinacher rectification section designed to charge a super-capacitor or rechargeable battery for later use. Multiple frequency bands are tapped for energy and this aspect of the implementation was one on the main focus points. The bands targeted for harvesting in this thesis will be those that are the most readily available to the general Canadian population. These include Wi-Fi hotspots (and other 2.4GHz sources), as well as cellular (850MHz band), Personal Communications Services (1900MHz band) and WiMax (2.3GHz) network transmitters.

Includes bibliographical references.