Australian carbon biosequestration and bioenergy policy co-evolution: mechanisms, mitigation and convergence

The intricacies of international land-use change and forestry policy reflect the temporal, technical and political difficulty of integrating biological systems and climate change mitigation. The plethora of co-existing policies with varied technical rules, accreditation requirements, accounting methods, market registries, etc., disguise the unequal efficacies of each mechanism. This work explores the co-evolution and convergence of Australian voluntary and mandatory climate-related policies at the biosequestration-bioenergy interface. Currently, there are temporal differences between the fast-evolving and precise climate-change mechanisms, and the long-term 'permanence' sought from land use changes encouraged by biosequestration instruments. Policy convergence that favours the most efficient, appropriate and scientifically substantiated policy mechanisms is required. These policies must recognise the fundamental biological foundation of biosequestration, bioenergy, biomaterial industrial development and other areas such as food security and environmental concerns. Policy mechanisms that provide administrative simplicity, project longevity and market certainty are necessary for rural and regional Australians to cost-effectively harness the considerable climate change mitigation potential of biological systems

A comparison of responses to single and repeated discrete choice questions

According to neoclassical economic theory, a stated preference elicitation format comprising a single binary choice between the status quo and one alternative is incentive compatible under certain conditions. Formats typically used in choice experiments comprising a sequence of discrete choice questions do not hold this property. In this paper, the effect on stated preferences of expanding the number of binary choice tasks per respondent from one to four is tested using a split sample treatment in an attribute-based survey relating to the undergrounding of overhead electricity and telecommunications wires. We find evidence to suggest that presenting multiple choice tasks per respondent decreases estimates of expected willingness to pay. Preferences stated in the first of a sequence of choice tasks are not significantly different from those stated in the incentive compatible single binary choice task, but, in subsequent choice tasks, responses are influenced by cost levels observed in past questions. Three behavioural explanations can be advanced – weak strategic misrepresentation, reference point revision and cost-driven value learning. The evidence is contrary to the standard assumption of truthful response with stable preferences.Choice experiment; willingness-to-pay; incentive compatibility; order effects; undergrounding

Aerodynamic parameter identification for an unmanned aerial vehicle

A dissertation submitted to the Faculty of Engineering and the Built Environment, School of Mechanical, Industrial and Aeronautical Engineering, University of the Witwatersrand, in fulfilment of the requirements for the degree of Master of Science in Engineering. Johannesburg, May 2016The present work describes the practical implementation of systems identification techniques to the development of a linear aerodynamic model for a small low-cost UAV equipped with a basic navigational and inertial measurement systems. The assessment of the applicability of the techniques were based on determining whether adequate aerodynamic models could be developed to aid in the reduction of wind tunnel testing when characterising new UAVs. The identification process consisted of postulating a model structure, flight test manoeuvre design, data reconstruction, aerodynamic parameter estimation, and model validation. The estimators that were used for the post-flight identification were the output error maximum likelihood method and an iterated extended Kalman filter with a global smoother. SIDPAC and FVSysID systems identification toolboxes were utilised and modified where appropriate. The instrumentation system on board the UAV consisted of three-axis accelerometers and gyroscopes, a three-axis vector magnetometer and GPS tracking while data was logged at 25 Hz. The angle of attack and angle of sideslip were not measured directly and were estimated using tailored data reconstruction methods. Adequate time domain lateral model correlation with flight data was achieved for the cruise flight condition. Adequacy was assessed against Theil’s inequality coefficients and Theil’s covariance. It was found that the simplified estimation algorithms based on the linearized equations of motion yielded the most promising model matches. Due to the high correlation between the pitch damping derivatives, the longitudinal analysis did not yield valid model parameter estimates. Even though the accuracy of the resulting models was below initial expectations, the detailed data compatibility analysis provided valuable insight into estimator limitations, instrumentation requirements and test procedures for systems identification on low-cost UAVs.MT201

TechNews digests: Jan - Nov 2009

TechNews is a technology, news and analysis service aimed at anyone in the education sector keen to stay informed about technology developments, trends and issues. TechNews focuses on emerging technologies and other technology news. TechNews service : digests september 2004 till May 2010 Analysis pieces and News combined publish every 2 to 3 month

Energy Systems Integration: Economics of a New Paradigm

Energy Systems Integration (ESI) is an emerging paradigm emanating from a whole system perspective of the energy sector. It is based on a holistic view in which the main energy carriers are integrated to achieve horizontal synergies and efficiencies at all levels. The energy system may in turn integrate with other infrastructure sectors such as water, transport, and telecommunications to meet the demand for a broad range of energy and essential services. It also implies that energy security, sustainability, and equity objectives can be balanced more effectively. There is already progress in the technical aspects of ESI. However, such systems require not only physical solutions but they also need economic, regulatory, and policy frameworks to ensure efficient performance over time. Thus, it is important to better understand the economic features of integrated energy systems. To our knowledge this aspect is barely addressed in the literature on ESI. This paper does not attempt to survey the technical literature on the topic but to describe some of its relevant economic features. We discuss selected aspects that relate to industrial organisation, regulation, business economics, and technology. Finally, we offer some early considerations and policy recommendations

An investigation into hybrid power trains for vehicles with regenerative braking

Imperial Users onl

Efficient Satellite Structural Design Optimised for Volume Production

In the past, the limited number and production volume of satellites has meant that their structural design has been essentially a one-off procedure. As a result, the most common choice of primary structural medium has been metal. Although eminently reliable and highly proven, this option has led to a comparatively high structural mass fraction of 20-24%. The emergence of communications satellite constellations creates the need for a complete reappraisal of current design practices. Emphasis needs to be given in the implementation of volume production methods, already matured through experience in the aviation industry, to manufacture of satellites. The prospect of new materials and technology can offer reductions in the overall structural mass of satellites in the region of 15-20% which in turn can lead to significant overall mass savings and reduced launched costs. However the aim of mass reduction can only be appreciated in terms of total cost savings, i.e. the net balance of the mass savings versus the technological application cost should be positive. This paper describes current approaches to the design of volume production satellites such as Technological Islands, Virtual Factory, Multifunctional Surfaces, Short Accelerated Production of Satellites (SNAPSAT) in respect of efficiency and economy. The implementation of volume production methods such as JIT and Taguchi in the area of satellite technology is also examined. Alternative designs for mass production satellite structures are considered. Ideas described include a conventional truss of both composite and aluminium manufacture and a corrugated plate modelled upon the multifunctional surface

The Thermodynamic Limit of Indoor Photovoltaics

Indoor Photovoltaic development stands between low-power devices such as the Internet of Things and their potential widespread roll out. Semiconductor material choice, of the active layer, has the potential to enhance indoor photovoltaic performance. To begin the early-stage research of indoor photovoltaic material choice, the thermodynamic compatibility of the material systems with the incident illumination spectrum was evaluated. While organic semiconductors present many advantages in the photovoltaic industry due to their low di-electric constants and cheap processibility over their respective inorganic counterparts, a standout advantage for use of organic semiconductors in indoor photovoltaic applications is their wider effective energy gaps. By adopting the principle of detailed balance and applying Shockley-Queisser limit calculations to pre-existing external quantum efficiency data and two chosen indoor lighting spectra, promising material systems were identified prior to fabrication and optimisation. As a result, predictions of two high-efficiency material systems were made and, in addition to a model system, were characterised in the remainder of this Thesis.In addition to the Shockley-Queisser analysis of existing material systems for characterisation under simulated indoor illumination conditions, theoretical limits, including radiative (Shockley-Queisser) and non-radiative (empirical models produced from the literature), were calculated for the two chosen light emitting diode radiation sources. From this analysis, it was evident that the optimal energy gap for an indoor photovoltaic system under these conditions was much wider than originally calculated for the scenario subject to solar illumination (1.14 eV). The optimal bandgap for the chosen light emitting diode source of 4000 K was equivalent to an effective energy gap of 1.89 eV, significantly higher than the energy gap that devices have been optimised towards historically, potentially capable of approximately 40% power conversion efficiency including non-radiative loss simulations at illuminances as low as 50 lux. Finally leading onto answering one of the aims of this Thesis; what is more important, thermodynamic compatibility or outperforming charge transport properties? Firstly, it can be considered that the EH-IDTBR and BTP-eC9 based devices are thermodynamically compatible and of above average charge transport properties. Therefore, with improvements to the short-circuit current, the thermodynamic compatibility could carry more weight in the optimisation of indoor organic photovoltaic devices.An additional investigation carried out through this Thesis is into the effect of shunt resistance on indoor organic photovoltaics. When observing both EH-IDTBR based systems, their varying shunt resistances (recorded via a dark characterisation process) present themselves significantly in the open-circuit voltage and fill factor dependence on light intensity. By performing these measurements, the incident illuminance at which the devices began to quickly deplete in performance was evaluated, therefore implying their importance.In summary, considering both the radiative and empirical non-radiative limits, the work presented in this Thesis provides valuable insight into the optimal effective energy gap for photovoltaic devices under two chosen model indoor illumination spectra. In addition, important evidence of the significant effect of shunt resistance on indoor photovoltaic device performance at low light intensities is presented, with conclusions that could make device selection more efficient for test under indoor characterisation. Finally, the importance of thermodynamic compatibility was emphasised. In combination, all of the aforementioned conclusions could potentially be used to aid the development of indoor organic photovoltaics

A comparison of responses to single and repeated discrete choice questions

According to neoclassical economic theory, a stated preference elicitation format comprising a single binary choice between the status quo and one alternative is incentive compatible under certain conditions. Formats typically used in choice experiments comprising a sequence of discrete choice questions do not hold this property. In this paper, the effect on stated preferences of expanding the number of binary choice tasks per respondent from one to four is tested using a split sample treatment in an attribute-based survey relating to the undergrounding of overhead electricity and telecommunications wires. We find evidence to suggest that presenting multiple choice tasks per respondent decreases estimates of expected willingness to pay. Preferences stated in the first of a sequence of choice tasks are not significantly different from those stated in the incentive compatible single binary choice task, but, in subsequent choice tasks, responses are influenced by cost levels observed in past questions. Three behavioural explanations can be advanced – weak strategic misrepresentation, reference point revision and cost-driven value learning. The evidence is contrary to the standard assumption of truthful response with stable preferences.Copyright Information: Authors own the copyright. Permission granted to archive the paper and make it publicly availabl