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Biopolymers are polymers produced by certain microorganisms, that are readily degradable in the environment. These biodegradable plastics have the potential to be used as substitutes for conventional petroleum based plastic provided that the production costs can be greatly reduced. The high cost of biopolymer production is due to the cost of substrate which mainly is glucose. / The enzymatic hydrolysis of potato processing wastes was to produce glucose as a least expensive feedstock substrate for the production of biopolymers of polyhydroxybutirate (PHB) from the bacterium Alcaligenes eutrophus was studied. The enzymatic hydrolysis experiments were carried out using $ alpha$-amylase liquefaction enzymes from Aspergillus oryzae and barley-malt, and amyloglucosidase saccharification enzyme from Rhizopus. / The results indicated that the production of glucose from potato starch waste to be used as a substrate to produce biopolymers was both technically and economically feasible. A 10 to 90 ratio of barley-malt to potato starch waste gave the highest conversion of starch to glucose of 194.30 gL$ sp{-1}$ (96.56%), and the lowest liquefaction enzyme cost ($0.054) to hydrolyze one kg of potato starch waste. { it A. eutrophus /} produced PHB of 5.0 gL$ sp-1$ (76.9 % of biomass) using the glucose substrate generated from the potato starch waste.

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Power consumption of CMOS digital logic designs has increased rapidly for the last several years. It has become an important issue, not only in battery-powered applications, but also in high-performance digital designs because of packaging and cooling requirements. At multi-GHz clock rates in use today, charging and discharging CMOS gates and wires, especially in clocks with their relatively large capacitances, leads to significant power consumption. Recovering and recycling the stored charge or energy about to be lost when these nodes are discharged to ground is a potentially good strategy that must be explored for use in future energy-efficient design methodologies. This dissertation investigates a number of novel clock energy recycling techniques to improve the overall power dissipation of high-performance logic circuits. If efficient recycling energy of the clock network can be demonstrated, it might be used in many high-performance chip designs, to lower power and save energy. A number of chip prototypes were designed and constructed to demonstrate that this energy can be successfully recycled or recovered in different ways: • Recycling clock network energy by supplying a secondary DC-DC power converter: the output of this power converter can be used to supply another region of the chip, thereby avoiding the need to draw additional energy from the primary supply. One test chip demonstrates energy in the final clock load can be recycled, while another demonstrates that clock distribution energy can be recycled. • Recovering clock network energy and returning it back to the power grid: each clock cycle, a portion of the energy just drawn from the supply is transferred back at the end of the cycle, effectively reducing the power consumption of the clock network. The recycling methods described in this thesis are able to preserve the more ideal square clock shape which has been a limitation of previous work in this area. Overall, the results provided in this thesis demonstrate that energy recycling is very promising and must be pursued in a number of other areas of the chip in order to obtain an energy-efficient design.

The project undertaken was aimed at extending a current craft based jewellery practice. Related by structure and materiality, the research sought to develop exploratory shapes as low seating objects to exist within small scale living spaces and studio apartments. Signaling an increased conscious way of thinking and working, a reflective process examining each form as series, provided an incremental creative strategy. The availability of discarded materials suggested possibilities for a sustainable cost effective option as a mode of contemporary practice. This combined approach was considered impact negative, diffusing global waste, and impact positive providing valid alternatives through functional and aesthetic objects. At present waste materials exist as products are still designed and made on the basis of planned obsolescence, thus an exploitation and escalation of global resources and resultant hazardous outcomes continues. Citing selected writings by Victor Papanek, (1992), and Edwin Datschefski, (2006) provided an understanding of the misuse high impact advanced technologies imposes on the environment. These notions were discussed during the project and in relation to contemporary models of practice which currently use discarded materials to make objects for living. Based on a survey observing the local homewares and furniture industries within Sydney, Australia, and recent published material, a niche market was discovered for challenging conventions of low seating objects. Initial sketches were transformed into marquettes then developed into full size prototypes of multi functional forms. a series of forms were scaled up, made of discarded materials using simple hand crafted processes and minimal production methods. As a reference influences included architects, sculptors and craft practitioners who were examined particularly for their use of discarded materials or for their construction methods. During experimental studies visual source material drew upon an observation and analysis of architecture, skeletal structures and land formations. In an exhibition originally titled, "Be Seated", these forms made as initial prototypes were exhibited at Kudos Gallery, Sydney, Australia, during May 2007. They were later refined and renamed as "Low Life" for a group exhibition "Contained" held at Kudos Gallery during 2008.

Doctor of Philosophy (PhD) / Developing an approach that delivers improved environmental performance for metal cycles is the aim of this thesis. Integral to the sustainable use of metals is the need to reduce environmental impacts associated with the mining, refining and recycling activities that supply metal to the economy. Currently, the links between the location and duration of these activities, their resultant impacts and the responsible parties are poorly characterised. Consequently, the changes to technology infrastructure and material flow patterns that are required to achieve sustainable metal cycles remain unclear to both industry and government actors. To address this problem, a holistic two-part methodology is developed. Firstly, a reference schema is developed to address the complexity of structuring analyses of the material chain at different geographical and time scales. The schema identifies actors and system variables at each scale of analysis and guides the level of information detail and performance indicators to be used in material chain characterisation. Material chain characterisation involves modelling material and energy flows for current activities as a series of connected nodes and linking these flows to resultant environmental impacts. The approach identifies the material chain activity responsible for each environmental impact and makes trade-offs between impacts explicit. Sensitivity analysis of the models identifies the key variables that enhance performance. The influence of actors over these variables is assessed to target areas for improvement. This first part of the methodology is illustrated using case studies that assess the current performance of copper material chain configurations at different geographical scales within the reference schema. The analysis of global material and energy flows indicates that the majority of environmental burden in the copper material chain is attributable to primary refining of metal from ore. Modelling of the dominant primary refining technologies using region-specific information for ore grade, technology mix and energy mix reveals that the total environmental impact differs by factors of 2–10 between world regions. The study of refined copper imports to Europe from various regions outside of Europe reveals that lower global warming impacts are achieved at the expense of increased local impacts from the producing regions. Overall, only limited improvements are possible without investing in new technology infrastructure. Evaluation of an innovative copper refining technology finds that collaboration with clean energy suppliers reduces global warming impacts more than changing process design parameters. To better assess the local impacts that are directly controllable by the technology operator, a new indicator incorporating the stability of solid waste is developed. In the second part of the methodology, the link established between actors, their control over key system variables and resultant impacts is used to design preferred future configurations for the material chain. Dynamic models are developed to evaluate transition paths towards preferred futures for individual and collaborative action by industry in the context of externally changing variables (for example, increasing demand for copper and declining available ore grades). Both new copper technology infrastructure and new material flow patterns are assessed in transitions toward preferred futures for a case study of the United States. The improvements resulting from the introduction of new primary refining technology by individual actors are negated by increasing impacts from declining copper ore grades over time. Achieving a combined reduction in local and global environmental impacts requires collaboration between industry actors to immediately increase the recycling of secondary scrap. Significantly, this methodology links actor decisions with their impacts across scales to prompt accountability for current performance and guide useful collaborations between actors. The methodology then delivers a comprehensive assessment of the scale and timing of required interventions to achieve more sustainable metal cycles.

Zugl.: Kassel, Univ., Diss., 2006 / Download lizenzpflichtig

Zugl.: Weimar, Bauhausuniv., Diss., 2007

Zugl.: Braunschweig, Techn. Universiẗat, Diss., 2005.

Techn. Universiẗat, Diss., 2006--Braunschweig.