title: Field data collection for implementation of Supercapacitor Assisted LED Lighting (SCALED)

authors: Norbu, Tenzin

subjects: Renewable energy

abstract: With the increasing impact of global warming, climate change is becoming the biggest threat for all life on our planet. The conventional way of generating electricity from the burning of fossil fuels releases significant amounts of carbon dioxide to the atmosphere, which contributes to the rise in the earth’s temperature. Moreover, fossil fuels are being consumed very rapidly and we now have limited resources, which need to be monitored to face future energy demands. The development of renewable energy sources, such as solar power, is a rapidly growing technology. With the extensive research and investment in this industry at present, in the near future solar power will be one of our leading renewable energy sources. Furthermore, as solar panels directly produce direct current (DC), they can be directly tied to a DC microgrid without requiring any power converter, thereby minimizing losses and increasing efficiency.
The supercapacitor assisted light emitting diode (SCALED) converter is one of the new circuit techniques under development for low voltage light emitting diode (LED) systems at the University of Waikato. In this circuit, an LED is connected in series with the supercapacitor bank forming part of a resistor-capacitor (RC) charging loop. This is to avoid energy losses in the RC charging loop, which can create, in the worst case, a 50% loss. As the commonly used 12 V LEDs are internally DC operated devices, SCALED will be applicable in DC microgrids, which are the emerging technology in low voltage distribution systems.
The groundwork for this project requires various solar-related field data collection and simulations for the successful implementation of this innovative technique. Unlike a conventional power supply, solar power output directly depends on the solar irradiance level, which is very unpredictable. Given the unique behaviour of solar panel output, starting with a near constant current behaviour and changing over to a practical voltage source with an approximately constant array resistance, combining a supercapacitor bank and an LED lamp will be a challenge in developing the SCALED topology. In addition, proper field measurements and analysis of these characteristics are essential to develop more efficient and reliable SCALED circuits for DC microgrid applications.

text: Field data collection for implementation of Supercapacitor Assisted LED Lighting (SCALED) With the increasing impact of global warming, climate change is becoming the biggest threat for all life on our planet. The conventional way of generating electricity from the burning of fossil fuels releases significant amounts of carbon dioxide to the atmosphere, which contributes to the rise in the earth’s temperature. Moreover, fossil fuels are being consumed very rapidly and we now have limited resources, which need to be monitored to face future energy demands. The development of renewable energy sources, such as solar power, is a rapidly growing technology. With the extensive research and investment in this industry at present, in the near future solar power will be one of our leading renewable energy sources. Furthermore, as solar panels directly produce direct current (DC), they can be directly tied to a DC microgrid without requiring any power converter, thereby minimizing losses and increasing efficiency.
The supercapacitor assisted light emitting diode (SCALED) converter is one of the new circuit techniques under development for low voltage light emitting diode (LED) systems at the University of Waikato. In this circuit, an LED is connected in series with the supercapacitor bank forming part of a resistor-capacitor (RC) charging loop. This is to avoid energy losses in the RC charging loop, which can create, in the worst case, a 50% loss. As the commonly used 12 V LEDs are internally DC operated devices, SCALED will be applicable in DC microgrids, which are the emerging technology in low voltage distribution systems.
The groundwork for this project requires various solar-related field data collection and simulations for the successful implementation of this innovative technique. Unlike a conventional power supply, solar power output directly depends on the solar irradiance level, which is very unpredictable. Given the unique behaviour of solar panel output, starting with a near constant current behaviour and changing over to a practical voltage source with an approximately constant array resistance, combining a supercapacitor bank and an LED lamp will be a challenge in developing the SCALED topology. In addition, proper field measurements and analysis of these characteristics are essential to develop more efficient and reliable SCALED circuits for DC microgrid applications.

year: 2018

title: Utilizing piezovibrocone in marine soils at Tauranga Harbor, New Zealand

authors: Jorat, M. Ehsan

subjects: Science & Technology

abstract: Piezovibrocones have been developed to evaluate the liquefaction potential of onshore soils, but have not yet been utilized to evaluate the in-situ liquefaction behavior of offshore marine and volcanoclastic sediments. Two static and vibratory CPTu (Cone Penetration Tests) were performed at Tauranga Harbor, New Zealand. The lithology is known from nearby drillholes and the influence of vibration on different types of marine soils is evaluated using the reduction ratio (RR) calculated from static and vibratory CPTu. A sediment layer with high potential for liquefaction and one with a slight reaction to cyclic loading are identified. In addition to the reduction ratio, the liquefaction potential of sediment is analyzed using classic correlations for static CPTu data, but no liquefaction potential was determined. This points to an underestimation of liquefaction potential with the classic static CPTu correlations in marine soil. Results show that piezovibrocone tests are a sensitive tool for liquefaction analysis in offshore marine and volcanoclastic soil.

text: Utilizing piezovibrocone in marine soils at Tauranga Harbor, New Zealand Piezovibrocones have been developed to evaluate the liquefaction potential of onshore soils, but have not yet been utilized to evaluate the in-situ liquefaction behavior of offshore marine and volcanoclastic sediments. Two static and vibratory CPTu (Cone Penetration Tests) were performed at Tauranga Harbor, New Zealand. The lithology is known from nearby drillholes and the influence of vibration on different types of marine soils is evaluated using the reduction ratio (RR) calculated from static and vibratory CPTu. A sediment layer with high potential for liquefaction and one with a slight reaction to cyclic loading are identified. In addition to the reduction ratio, the liquefaction potential of sediment is analyzed using classic correlations for static CPTu data, but no liquefaction potential was determined. This points to an underestimation of liquefaction potential with the classic static CPTu correlations in marine soil. Results show that piezovibrocone tests are a sensitive tool for liquefaction analysis in offshore marine and volcanoclastic soil.

year: 2015-07-01

title: Tūhoe on the move: Regional mobility

authors: Guerin, Pauline

abstract: Academic interest in geographic mobility of indigenous peoples has increased in recent years with a corresponding growth in the literature relating to Māori mobility more specifically. With this greater acknowledgement of Māori issues has also come an awareness of the need for iwi-specific research because of the diversity within and between Māori and iwi. The present research contributes to a larger project exploring Tūhoe regional mobility. In this paper, we analyse published data and unpublished census data from 2001 that relate specifically to Tūhoe regional mobility and the relationship between mobility and language. Region of residence in 1996 and 2001 were analysed in relation to age, sex, and broad language groups. Overall, this analysis found important and diverse relationships between age, sex, language, and region of residence in New Zealand among Māori who identify as Tūhoe. For example, patterns of mobility for different age groups and sex had some similarities with other research, such as a higher proportion of “stayers” in older age groups, but differences were also found, such as higher proportions of “movers” among females in some age groups. Interestingly, we found that language between “movers” and “stayers” differed depending on the region of residence. A greater proportion of “movers” were able to converse in Māori in Auckland and the Waikato, but a slightly greater proportion of “stayers” could converse in Māori in the Hawke’s Bay and Bay of Plenty. These results suggest that geographic mobility among Māori, and Tūhoe more specifically, are complex and should not be overly-simplified in more aggregate analyses.

text: Tūhoe on the move: Regional mobility Academic interest in geographic mobility of indigenous peoples has increased in recent years with a corresponding growth in the literature relating to Māori mobility more specifically. With this greater acknowledgement of Māori issues has also come an awareness of the need for iwi-specific research because of the diversity within and between Māori and iwi. The present research contributes to a larger project exploring Tūhoe regional mobility. In this paper, we analyse published data and unpublished census data from 2001 that relate specifically to Tūhoe regional mobility and the relationship between mobility and language. Region of residence in 1996 and 2001 were analysed in relation to age, sex, and broad language groups. Overall, this analysis found important and diverse relationships between age, sex, language, and region of residence in New Zealand among Māori who identify as Tūhoe. For example, patterns of mobility for different age groups and sex had some similarities with other research, such as a higher proportion of “stayers” in older age groups, but differences were also found, such as higher proportions of “movers” among females in some age groups. Interestingly, we found that language between “movers” and “stayers” differed depending on the region of residence. A greater proportion of “movers” were able to converse in Māori in Auckland and the Waikato, but a slightly greater proportion of “stayers” could converse in Māori in the Hawke’s Bay and Bay of Plenty. These results suggest that geographic mobility among Māori, and Tūhoe more specifically, are complex and should not be overly-simplified in more aggregate analyses.

year: 2006