Decolourization of wood-ethanol stillage using a granular activated carbon packed anaerobic expanded-bed reactor : a thesis presented in partial fulfilment of requirements for the degree of Master of Technology in Biotechnology at Massey University /

The anaerobic treatment (including decolourization) of wood-ethanol stillage from the Forest Research Institute (FRI) wood-hydrolysis pilot plant at Rotorua has been investigated using granular activated carbon (GAC) packed expanded-bed reactors. Specifically, bioregeneration of the GAC in the reactors in terms of organic and colour removal has been considered. Two 7.2 1 anaerobic expanded bed (AEB) reactors were designed and built. Reactor One (R1) was used for the anaerobic digestion of raw wood-ethanol stillage and Reactor Two (R2) for the decolourization of anaerobic lagoon pretreated wood-ethanol stillage. For R1, a desulphated stillage feed (to 500 mg.1-1sulphate) was used. Depending on the organic loading rate (OLR), the additions of nitrogen (N), phosphorus (P) and alkalinity reagent ranged from 240-350 mg.l-1, 80-250 mg.l-1 and 2.5- 4.5 ml 20% w/v NaOH per litre feed respectively. Only N and P feed supplements were used for R2 at 240 and 80 mg.l-1 respectively. The reactors' performance and stability were closely monitored through analyses of volatile fatty acid's, pH, alkalinity, colour, chemical oxygen demand (COD), sulfide, biogas production rate and methane composition, solids concentrations, N and P. After operating R1 for 227 days, it was demonstrated that this system, is superior to the previous systems reported for the treatment of a similar stillage. A non-maximal OLR of 29.0 kg tCOD.m-3.d-1 at 0.85 d hydraulic retention time (HRT) with total and soluble COD (tCOD and sCOD) removals of 74.5 and 83.5% respectively were achieved. Digestion stability was excellent with acetate at 160 mg.l-1, propionate at 490 mg.l-1 and a gas methane composition of 61.0%. The colour loading rate was 4.7 kg chloroplatinate.m-3.d-1 with a 75% colour removal. Higher colour and COD removals may be obtained by operating at a longer HRT (e.g. the percentage colour and sCOD removals were 90.6 and 91.8% respectively at a 2 d HRT). Previously, no significant colour removal for the anaerobic digestion of wood-ethanol stillage has been reported. In this study, only approximately 9% w/v of the chromophoric materials present in the wood-ethanol stillage are particularly recalcitrant to anaerobic degradation. The methane gas yield was near to that predicted by theory (99.7% at 2 d HRT) with a very low sludge yield (2.8% based on 91.8% sCOD removal). Consequently, the AEB reactor had a very low nutrient requirement for effective treatment. In terms of reactor stability, it can accomodate very high hydraulic loading rates (less than 0.85 d) without problems of cell washout. The use of activated carbon medium also provides a toxicity sequesting potential against biological inhibitors present in the wood-ethanol stillage. Continuous bioregeneration of the GAC in R1 has also been demonstrated using sCOD and colour breakthrough curves for GAC adsorption with and without biological activity. Microbial degradation of the chromophoric species has been confirmed using UV-visible spectrophotometric scans. Little methanogenic activity was observed in R2 in its 191 days of operation due to the recalcitrant nature of the anaerobic lagoon pretreated stillage. Only approximately 20% bioregeneration of GAC in terms of colour removal was achieved at a colour loading rate of 1.2 kg chloroplatinate.m-3.d-1. This study has demonstrated that the GAC packed expanded-bed reactor (R1) provides a very effective treatment of wood-ethanol stillage (including decolourization) while recovering a very significant portion (89%) of the stillage energy. Considerable capital and operating cost savings are possible using the AEB system since effective treatment can be achieved in a single step utilizing a relatively small reactor with minimal nutrient, sludge disposal and GAC regeneration or replacement costs. The only disadvantages of the system are the carbon cost, a long start-up period of 5 months and a recycle energy cost to maintain an expanded-bed. It is believed that they can partly be reduced by using a GAC carrier with a smaller particle size. Anaerobic digestion, utilizing a GAC packed expanded-bed reactor, thus represents a cost effective and commercially attractive option for the utilization/disposal of wood-ethanol stillage

Engineering the composition, morphology, and optical properties of InAsSb nanostructures via graded growth technique

Graded growth technique is utilized to realize the control over the composition, morphology, and optical properties of self-assembled InAsSb/InGaAs/InP nanostructures. By increasing the initial mole fraction of the Sb precursor during the graded growth of InAsSb, more Sb atoms can be incorporated into the InAsSb nanostructures despite the same Sb mole fraction averaged over the graded growth. This leads to a shape change from dots to dashes/wires for the InAsSb nanostructures. As a result of the composition and morphology change, photoluminescence from the InAsSb nanostructures shows different polarization and temperature characteristics. This work demonstrates a technologically important technique—graded growth, to control the growth and the resultant physical properties of self-assembled semiconductor nanostructures.Financial support from Australian Research Council is gratefully acknowledged

Multiple wavelength InGaAs quantum dot lasers using selective area epitaxy

The authors demonstrate multiple wavelength lasers fabricated from InGaAsquantum dots. Selective area epitaxy is used to grow the active region, consisting of five layer stack of InGaAsquantum dots with different band gapenergies in selected regions of the substrate, for fabrication of the lasers. The mechanism responsible for engineering of the band gap of quantum dots is discussed. The performance of the selectively grown lasers is compared to the lasers fabricated from structures grown in a standard, nonselective area growth process.The Australian Research Council is gratefully acknowledged for financial support

China’s Changing Economic Structures and Its Implications for Regional Patterns of Trade Production and Integration

There is tremendous momentum for economic and financial integration in East Asia today. Partly inspired by the formation of the European Union and partly as a response to the 1997/98 Asia financial crisis, many East Asian countries are showing greater commitment to regional economic cooperation. A number of bilateral free trade agreements (FTAs) have either been concluded or are being negotiated.1 At a less formal level, the ASEAN+3 grouping has brought the whole region together in regular consultations over trade, investment, as well as monetary and exchange rate policy matters.

China’s Changing Economic Structures and Its Implications for Regional Patterns of Trade Production and Integration

There is tremendous momentum for economic and financial integration in East Asia today. Partly inspired by the formation of the European Union and partly as a response to the 1997/98 Asia financial crisis, many East Asian countries are showing greater commitment to regional economic cooperation. A number of bilateral free trade agreements (FTAs) have either been concluded or are being negotiated.1 At a less formal level, the ASEAN+3 grouping has brought the whole region together in regular consultations over trade, investment, as well as monetary and exchange rate policy matters. Few countries in East Asia harbor any illusion of realizing a region-wide economic union any time soon, although there were clear attempts by some of them in this direction.2 A crucial ingredient in any successful East Asia-wide economic integration effort is the role of China. China could be a major catalyst to the integration process if it chooses to. But it would do so only if such a move is in line with the overall objectives of its foreign economic policy. More importantly, it must be consistent with Chinas domestic economic agenda. In this paper, we examine trends and developments in the regional pattern of trade and production and link it to the evolving structure of Chinas economy. We argue that there is scope for China to play a more active role and provide stronger leadership in East Asian economic integration. In our view, the developmental pattern in Chinas domestic economy and the likely changes in Chinas production and trade structures will justify such a policy approach. Doing so will also help improve Chinas economic and political relationship with the region.trade, China, East Asian economic integration, East Asia

The state of commercial augmentative biological control: plenty of natural enemies, but a frustrating lack of uptake

Augmentative biological control concerns the periodical release of natural enemies. In com- mercial augmentative biological control, natural enemies are mass-reared in biofactories for release in large numbers to obtain an immediate control of pests. The history of commercial mass production of natural enemies spans a period of roughly 120 years. It has been a successful, environmentally and eco- nomically sound alternative for chemical pest control in crops like fruit orchards, maize, cotton, sugar cane, soybean, vineyards and greenhouses. Currently, aug- mentative biological control is in a critical phase, even though during the past decades it has moved from a cottage industry to professional production. Many efficient species of natural enemies have been discovered and 230 are commercially available today. The industry developed quality control guidelines, mass production, shipment and release methods as well as adequate guidance for farmers. However, augmentative biological control is applied on a frustratingly small acreage. Trends in research and application are reviewed, causes explaining the limited uptake are discussed and ways to increase application of augmentative biological control are explored

Intermixing of InGaAs/GaAs quantum wells and quantum dots using sputter-deposited silicon oxynitride capping layers

Various approaches can be used to selectively control the amount of intermixing in III-Vquantum well and quantum dotstructures. Impurity-free vacancy disordering is one technique that is favored for its simplicity, however this mechanism is sensitive to many experimental parameters. In this study, a series of silicon oxynitride capping layers have been used in the intermixing of InGaAs/GaAs quantum well and quantum dotstructures. These thin films were deposited by sputter deposition in order to minimize the incorporation of hydrogen, which has been reported to influence impurity-free vacancy disordering. The degree of intermixing was probed by photoluminescence spectroscopy and this is discussed with respect to the properties of the SiOxNyfilms. This work was also designed to monitor any additional intermixing that might be attributed to the sputtering process. In addition, the high-temperature stress is known to affect the group-III vacancy concentration, which is central to the intermixing process. This stress was directly measured and the experimental values are compared with an elastic-deformation model.This work has been made possible with access to the ACT Node of the Australian National Fabrication Facility and through the financial support of the Australian Research Council

Effect of Mandibular Displacement on Condylar Cartilage Remodelling In Sprague Dawley Rats: A Micro-Structural Analysis

Three dimensional (3D) imaging of cartilage has always been difficult due to the inherent intermediary density between soft tissue and hard tissue in X-rays images, particularly in Micro Computer Tomography (MicroCT). Recent advances in imaging techniques have allowed for the enhancement of cartilage visualization for MicroCT use. Aim: The objective of this study was to provide a new insight in understanding changes in condylar cartilage, determined qualitatively and quantitatively, with normal growth and after the placement of an appliance over a 4 week period. Materials and Methods: Seventy Sprague Dawley rats (five weeks old) were divided into either a control group or an experimental group in which bite ramps were placed on the lower incisors at Day 0. Animals were sacrificed at Days 0, 7, 21 and 28. Right hemisections were then taken and stained with gadolinium chloride for six days before being scanned via a MicroCT unit. Condylar cartilage was digitally extracted from the scans and volumetric measurements were carried out and assessed quantitatively. Three dimensional images of the condyles were also assessed qualitatively for morphological changes between appliances and over the experimental duration. An intra-individual method error study was also carried out. Results Conformational changes were noted in the shape of the condyle between appliance groups and over the treatment duration. Qualitative assessment of the condyles demonstrated a reduction in size over time in all groups with a change in shape of the condylar heads. Anterior displacement of the mandible resulted in significant remodeling and distinctive shape changes that differ from both control and posterior displacement groups. Quantitative analysis demonstrated differences between control and appliance groups in regards to Total volume of the whole condylar head, Total cartilage volume, Total volume of the posterior hemisection of the condylar head and Posterior cartilage volume. The Method error study demonstrated the high reproducibility of results with a coefficient of variation of 5-13%. Discussion This study demonstrated a new method for analysing changes in the condylar head following orthopaedic intervention. Assessment of these changes in the condylar head can now be depicted via a three dimensional, non-destructive method. Hence, growth changes of the condylar head can now be evaluated in its totality compared to traditional methods of assessing cartilage changes sectionally via histological slices. Therefore, this provides a new avenue for improving our understanding in the changes that occur in the condylar head with growth and after intervention. It may also promote further investigations into the effects of systemic drugs on normal growth and manipulation of this important site of growth