A particle-based micromechanics approach to simulate structural changes of plant cells during drying

This paper is concerned with applying a particle-based approach to simulate the micro-level cellular structural changes of plant cells during drying. The objective of the investigation was to relate the micro-level structural properties such as cell area, diameter and perimeter to the change of moisture content of the cell. Model assumes a simplified cell which consists of two basic components, cell wall and cell fluid. The cell fluid is assumed to be a Newtonian fluid with higher viscosity compared to water and cell wall is assumed to be a visco-elastic solid boundary located around the cell fluid. Cell fluid is modelled with Smoothed Particle Hydrodynamics (SPH) technique and for the cell wall; a Discrete Element Method (DEM) is used. The developed model is two-dimensional, but accounts for three-dimensional physical properties of real plant cells. Drying phenomena is simulated as fluid mass reductions and the model is used to predict the above mentioned structural properties as a function of cell fluid mass. Model predictions are found to be in fairly good agreement with experimental data in literature and the particle-based approach is demonstrated to be suitable for numerical studies of drying related structural deformations. Also a sensitivity analysis is included to demonstrate the influence of key model parameters to model predictions.

Higher education for capacity development or revenue maximisation? Lessons from transnational higher education programs at two Indonesian universities

HE has been changing rapidly due to globalisation that has increased the interconnectedness between nations and people throughout the world (Mok, 2012). As HE has manifested into different forms and governed by competing rationales in recent years, this paper focuses on transnational HE, which is an example of the interconnectedness of universities beyond the national borders. Indonesia is also influenced by the above changes. It took part in free-trade agreements that include HE as a sector to be liberated and accessed by international providers (Nizam, 2006). Indonesian universities found themselves bracing for the global competition for students and simultaneously having to improve their quality in order to survive amidst the growing competition. This competition gave birth to joint transnational HE programs with overseas partners among many Indonesian universities (Macaranas, 2010).

Towards a commercial lignocellulosic ethanol industry in Australia : the Mackay Renewable Biocommodities Pilot Plant

In 2007, the Queensland University of Technology (QUT) received funding from the Australian Government through the NCRIS program and from the then Queensland Government Department of State Development to construct a pilot research and development facility for the production of bioethanol and other renewable biocommodities from biomass including sugar cane bagasse. This facility is being constructed adjacent to the Racecourse Sugar Mill in Mackay and is known as the Mackay Renewable Biocommodities Pilot Plant (MRBPP). The MRBPP will be capable of processing biomass through a pressurised pretreatment reactor and includes equipment for enzymatic saccharification, fermentation and distillation to produce ethanol. Lignin and fermentation co-products will also be produced at a pilot scale for product development and testing.

An update on the Mackay Renewable Biocommodities Pilot Plant : preliminary trial results

THE Mackay Renewable Biocommodities Pilot Plant is a pilot scale facility owned and operated by QUT for research and demonstration of the conversion of lignocellulosic biomass such as sugarcane bagasse into biofuels. The pilot plant accommodates unique state-of-the-art equipment to process a wide range of feedstocks and is strategically located on the site of the Mackay Sugar Ltd Racecourse Mill. Major facilities include a biomass handling system, pre-treatment reactor, saccharification reactor, fermentors, distillation column and bioseparations equipment. This paper provides an update on the design, construction, commissioning and start-up of the facility. In addition, the paper provides results from preliminary facility trials on the pre-treatment of sugarcane bagasse for cellulosic ethanol production.

"Please touch the plant on your way up the stairs..."

We are aware of global concerns of sustainability and are encouraged on many fronts to modify our behaviour to save the planet but sometimes this understanding is more intellectual than motivated. An opportunity was identified within the university environment to activate a pilot study to investigate the level of voluntary student engagement in saving energy if a plant/digital interface were introduced. We postulate that people may be more inclined to participate in a "green" activity if they are more directly aware of the benefits. This project also seeks to discover if the introduction of nature (green plants) as the interface would encourage users to increase participation in socially responsive activities. Using plants as the interface offers an immediate sensory connection between the participants and the outcome of their chosen actions. This may generate a deeper awareness of the environment by enabling the participant to realise that their one small action in an ordinary day can contribute positively to larger global issues.

Active and reactive power control of synchronous generator for the realization of a virtual power plant

This paper presents a novel power control strategy that decouples the active and reactive power for a synchronous generator connected to a power network. The proposed control paradigm considers the capacitance of the transmission line along with its resistance and reactance as-well. Moreover the proposed controller takes into account all cases of R-X relationships, thus allowing it to function in Virtual Power Plant (VPP) structures which operate at both medium voltage (MV) and low voltage (LV) levels. The independent control of active and reactive power is achieved through rotational transformations of the terminal voltages and currents at the synchronous generator's output. This paper details the control technique by first presenting the mathematical and electrical network analysis of the methodology and then successfully implementing the control using MATLAB-SIMULINK simulation.

Systematics and biology of the iconic Australian scribbly gum moths Ogmograptis Meyrick (Lepidoptera: Bucculatricidae) and their unique insect-plant interaction

The larvae of particular Ogmograptis spp. produce distinctive scribbles on some smooth-barked Eucalyptus spp. which are a common feature on many ornamental and forest trees in Australia. However, although they are conspicuous in the environment the systematics and biology of the genus has been poorly studied. This has been addressed through detailed field and laboratory studies of their biology of three species (O. racemosa Horak sp. nov., O. fraxinoides Horak sp. nov., O. scribula Meyrick), in conjunction with a comprehensive taxonomic revision support by a molecular phylogeny utilising the mitochondrial Cox1 and nuclear 18S genes. In brief, eggs are laid in bark depressions and the first instar larvae bore into the bark to the level where the future cork cambium forms (the phellegen). Early instar larvae bore wide, arcing tracks in this layer before forming a tighter zig-zag shaped pattern. The second last instar turns and bores either closely parallel to the initial mine or doubles its width, along the zig-zag shaped mine. The final instar possesses legs and a spinneret (unlike the earlier instars) and feeds exclusively on callus tissue which forms within the zig-zag shaped mine formed by the previous instar, before emerging from the bark to pupate at the base of the tree. The scars of mines them become visible scribble following the shedding of bark. Sequence data confirm the placement of Ogmograptis within the Bucculatricidae, suggest that the larvae responsible for the ‘ghost scribbles’ (unpigmented, raised scars found on smooth-barked eucalypts) are members of the genus Tritymba, and support the morphology-based species groups proposed for Ogmograptis. The formerly monotypic genus Ogmograptis Meyrick is revised and divided into three species groups. Eleven new species are described: Ogmograptis fraxinoides Horak sp. nov., Ogmograptis racemosa Horak sp. nov. and Ogmograptis pilularis Horak sp. nov. forming the scribula group with Ogmograptis scribula Meyrick; Ogmograptis maxdayi Horak sp. nov., Ogmograptis barloworum Horak sp. nov., Ogmograptis paucidentatus Horak sp. nov., Ogmograptis rodens Horak sp. nov., Ogmograptis bignathifer Horak sp. nov. and Ogmograptis inornatus Horak sp. nov. as the maxdayi group; Ogmograptis bipunctatus Horak sp. nov., Ogmograptis pulcher Horak sp. nov., Ogmograptis triradiata (Turner) comb. nov. and Ogmograptis centrospila (Turner) comb. nov. as the triradiata group. Ogmograptis notosema (Meyrick) cannot be assigned to a species group as the holotype has not been located. Three unique synapomorphies, all derived from immatures, redefine the family Bucculatricidae, uniting Ogmograptis, Tritymba Meyrick (both Australian) and Leucoedemia Scoble & Scholtz (African) with Bucculatrix Zeller, which is the sister group of the southern hemisphere genera. The systematic history of Ogmograptis and the Bucculatricidae is discussed.

Nature and genesis of clay minerals of the Rustler Formation in the vicinity of the Waste Isolation Pilot Plant in Souteastern New Mexico

Detailed mineralogical studies of the matrix and fracture-fill materials of a large number of samples from the Rustler Formation have been carried out using x-ray diffraction, high-resolution transmission electron microscopy, electron microprobe analysis, x-ray fluorescence, and atomic absorption spectrophotometry. These analyses indicate the presence of four clay minerals: interstratified chlorite/saponite, illite, chlorite, and serpentine. Corrensite (regularly stratified chlorite/saponite) is the dominant clay mineral in samples from the Culebra dolomite and two shale layers of the lower unnamed member of the Rustler Formation. Within other layers of the Rustler Formation, disordered mixed chlorite/saponite is usually the most abundant clay mineral. Studies of the morphology and composition of clay crystallites suggest that the corrensite was formed by the alteration of detrital dioctahedral smectite in magnesium-rich pore fluids during early diagenesis of the Rustler Formation. This study provides initial estimates of the abundance and nature of the clay minerals in the Culebra dolomite in the vicinity of the Waste Isolation Pilot Plant.

Spatial and temporal foraging patterns of Queensland fruit fly, Bactrocera tryoni(Froggatt) (Diptera: Tephritidae), for protein and implications for management

Fruit flies require protein for reproductive development and actively feed upon protein sources in the field. Liquid protein baits mixed with insecticide are used routinely to manage pest fruit flies, such as Bactrocera tryoni (Froggatt). However, there are still some gaps in the underpinning science required to improve the efficacy of bait spray technology. The spatial and temporal foraging behaviour of B. tryoni in response to protein was investigated in the field. A series of linked trials using either wild flies in the open field or laboratory-reared flies in field cages and a netted orchard were undertaken using nectarines and guavas. Key questions investigated were the fly's response to protein relative to: height of protein within the canopy, fruiting status of the tree, time of day, season and size of the experimental arena. Canopy height had a significant response on B. tryoni foraging, with more flies foraging on protein in the mid to upper canopy. Fruiting status also had a significant effect on foraging, with most flies responding to protein when applied to fruiting hosts. B. tryoni demonstrated a repeatable diurnal response pattern to protein, with the peak response being between 12:00–16:00 h. Season showed significant but unpredictable effects on fruit fly response to protein in the subtropical environment where the work was undertaken. Relative humidity, but not temperature or rainfall, was positively correlated with protein response. The number of B. tryoni responding to protein decreased dramatically as the spatial scale increased from field cage through to the open field. Based on these results, it is recommend that, to be most effective, protein bait sprays should be applied to the mid to upper canopies of fruiting hosts. Overall, the results show that the protein used, an industry standard, has very low attractancy to B. tryoni and that further work is urgently needed to develop more volatile protein baits.

Five commercial citrus rate poorly as hosts of the polyphagous fruit flyBactrocera tryoni(Froggatt) (Diptera: Tephritidae) in laboratory studies

Queensland fruit fly, Bactrocera tryoni (Froggatt), is a polyphagous pest, and many citrus types are included among its hosts. While quantification of citrus host use by B. tryoni is lacking, citrus is generally considered a ‘low pressure’ crop. This paper investigates B. tryoni female oviposition preference and offspring performance in five citrus types; Murcott mandarin (Citrus reticulata), Navel orange and Valencia orange (Citrus sinensis), Eureka lemon (Citrus limon) and yellow grapefruit (Citrus paradisi). Oviposition preference was investigated in laboratory-based choice and no-choice experiments, while immature survival and offspring performance were investigated by infesting fruits in the laboratory and evaluating pupal recovery, pupal emergence and F1 fecundity. Fruit size, Brix level and peel toughness were also measured for correlation with host use. Bactrocera tryoni demonstrated an oviposition preference hierarchy among the citrus fruits tested; Murcott and grapefruit were most preferred for oviposition and lemon the least, while preference for Navel and Valencia was intermediate. Peel toughness was negatively correlated with B. tryoni oviposition preference, while no significant correlations were detected between oviposition and Brix level or fruit size. Immature survival in the tested fruit was very low. Murcott was the best host (21% pupal recovery), while all other citrus types that showed pupal recovery of 6% or lower and no pupae were recovered from Valencia orange. In pupae recovered from Navel orange and lemon, adult eclosion was greatly reduced, while in grapefruit and lemon, no eggs were recovered from F1 adults. Based on these laboratory results, many commercial citrus varieties appear to be poor hosts for B. tryoni and may pose a low post-harvest and quarantine risk. These findings need to be confirmed in the field, as they impact on both pre-harvest and post-harvest countermeasures.

Optimisation of bio-oil extraction process from Beauty Leaf (Calophyllum inophyllum) oil seed as a second generation biodiesel source

The Beauty Leaf tree (Calophyllum inophyllum) is a potential source of non-edible vegetable oil for producing future generation biodiesel because of its ability to grow in a wide range of climate conditions, easy cultivation, high fruit production rate, and the high oil content in the seed. This plant naturally occurs in the coastal areas of Queensland and the Northern Territory in Australia, and is also widespread in south-east Asia, India and Sri Lanka. Although Beauty Leaf is traditionally used as a source of timber and orientation plant, its potential as a source of second generation biodiesel is yet to be exploited. In this study, the extraction process from the Beauty Leaf oil seed has been optimised in terms of seed preparation, moisture content and oil extraction methods. The two methods that have been considered to extract oil from the seed kernel are mechanical oil extraction using an electric powered screw press, and chemical oil extraction using n-hexane as an oil solvent. The study found that seed preparation has a significant impact on oil yields, especially in the screw press extraction method. Kernels prepared to 15% moisture content provided the highest oil yields for both extraction methods. Mechanical extraction using the screw press can produce oil from correctly prepared product at a low cost, however overall this method is ineffective with relatively low oil yields. Chemical extraction was found to be a very effective method for oil extraction for its consistence performance and high oil yield, but cost of production was relatively higher due to the high cost of solvent. However, a solvent recycle system can be implemented to reduce the production cost of Beauty Leaf biodiesel. The findings of this study are expected to serve as the basis from which industrial scale biodiesel production from Beauty Leaf can be made.

A general model for host plant selection in phytophagous insects

We develop a general theoretical framework for exploring the host plant selection behaviour of herbivorous insects. This model can be used to address a number of questions, including the evolution of specialists, generalists, preference hierarchies, and learning. We use our model to: (i) demonstrate the consequences of the extent to which the reproductive success of a foraging female is limited by the rate at which they find host plants (host limitation) or the number of eggs they carry (egg limitation); (ii) emphasize the different consequences of variation in behaviour before and after landing on (locating) a host (termed pre- and post-alighting, respectively); (iii) show that, in contrast to previous predictions, learning can be favoured in post-alighting behaviour--in particular, individuals can be selected to concentrate oviposition on an abundant low-quality host, whilst ignoring a rare higher-quality host; (iv) emphasize the importance of interactions between mechanisms in favouring specialization or learning.

Intra-specific variation for host plant use in Helicoverpa armigera (Hubner) (Lepidoptera : Noctuidae) : implications for management

The polyphagous moth Helicoverpa armigera (Hübner) is one of the world's most important agricultural pests. A number of existing approaches and future designs for management of H. armigera rely on the assumption that moths do not exhibit either genetically and/or non-genetically based variation for host plant utilization. We review recent empirical evidence demonstrating that both these forms of variation influence host plant use in this moth. The significance of this variation in H. armigera in relation to current and future pest management strategies is examined. We provide recommendations on future research needs and directions for sustainable management of H. armigera, under a framework that includes consideration of intra-specific variation for host use relevant in this and other similar pest species.