Advanced computer simulation of the milling process

Process modelling is an integral part of any process industry. Several sugar factory models have been developed over the years to simulate the unit operations. An enhanced and comprehensive milling process simulation model has been developed to analyse the performance of the milling train and to assess the impact of changes and advanced control options for improved operational efficiency. The developed model is incorporated in a proprietary software package ‘SysCAD’. As an example, the milling process model has been used to predict a significant loss of extraction by returning the cush from the juice screen before #3 mill instead of before #2 mill as is more commonly done. Further work is being undertaken to more accurately model extraction processes in a milling train, to examine extraction issues dynamically and to integrate the model into a whole factory model.

Issues associated with using trash as a cogeneration fuel

Considerable work has been undertaken to determine an economical process to provide sugarcane trash as a fuel for cogeneration. This paper reviews efforts to provide that trash fuel by harvesting, transporting and processing the trash with the cane. Harvesting trash with the cane has the advantage that cane that would otherwise be lost by extracting it with the trash is captured and sugar can be produced from that cane. Transporting trash with the cane significantly reduces the bulk density of the cane, requiring substantial changes and costs to cane transport. Shredding the trash at the harvester and compacting the cane in the bin prior to transport are possible methods to increase the bulk density but both have considerable cost. Processing trash through the sugar factory with the cane significantly reduces sugar recovery and sugar quality. Although considerable knowledge has been gained of these effects and further analysis has provided insights into their causes, much more work is required before whole crop harvesting and transport is an economically viable means of trash recovery.

Effect of chute level on mill capacity

IN MANY FACTORIES, the feed chute of the first mill is operated with a high chute level for the purpose of maximising the cane rate through the mill. There is a trend towards trying to control chute level within a small control range near the top of a chute that can result in rapid changes in cane feeding rate to maintain the chute level set point. This paper reviews the theory that predicts higher cane rate with higher chute level and discusses the main weakness in the theory that it does not consider the beneficial effect on capacity of cane falling from the top of the chute to the top surface of the cane mat. An extension to the chute theory model is described that predicts higher capacity with lower chute level because of the effect of the falling cane. The original model and this extended model are believed to be the upper and lower limits to the true effect. The paper reports an experiment that measured the real effect of chute level on capacity and finds that increasing chute level does lead to higher capacity but that the trend is only about one-third as strong as the original theory predicted. The paper questions whether the benefits of slightly greater capacity outweigh the costs of operating with the small control range near the top of the chute.

Addressing factory needs in cane variety selection

Cane fibre content has increased over the past ten years. Some of that increase can be attributed to new varieties selected for release. This paper reviews the existing methods for quantifying the fibre characteristics of a variety, including fibre content and fibre quality measurements – shear strength, impact resistance and short fibre content. The variety selection process is presented and it is reported that fibre content has zero weighting in the current selection index. An updated variety selection approach is proposed, potentially replacing the existing selection process relating to fibre. This alternative approach involves the use of a more complex mill area level model that accounts for harvesting, transport and processing equipment, taking into account capacity, efficiency and operational impacts, along with the end use for the bagasse. The approach will ultimately determine a net economic value for the variety. The methodology lends itself to a determination of the fibre properties that have a significant impact on the economic value so that variety tests can better target the critical properties. A low-pressure compression test is proposed as a good test to provide an assessment of the impact of a variety on milling capacity. NIR methodology is proposed as a technology to lead to a more rapid assessment of fibre properties, and hence the opportunity to more comprehensively test for fibre impacts at an earlier stage of variety development.

An alternative approach to setting a mill

The conventional approach to setting a milling unit is essentially based on the desire to achieve a particular bagasse moisture content or fibre fill in each nip of the mill. This approach relies on the selection of the speed at which the mill will operate for the selected fibre rate. There is rarely any checking that the selected speed or the selected fibre fill is achieved and the same set of assumptions is generally carried over to use again in the next year. The conventional approach largely ignores the fact that the selection of mill settings actually determines the speed at which the mill will operate. Making an adjustment with the intent of changing the performance of the mill often also changes the speed of the mill as an unintended consequence. This paper presents an alternative approach to mill setting. The approach discussed makes use of mill feeding theory to define the relationship between fibre rate, mill speed and mill settings and uses that theory to provide an alternative means of determining the settings in some nips of the mill. Mill feeding theory shows that, as the feed work opening reduces, roll speed increases. The theory also shows that there is an optimal underfeed opening and Donnelly chute exit opening that will minimise roll speed and that the current South African guidelines appear to be well away from those optimal values.

Choice impulsivity: Definitions, measurement issues, and clinical implications

Background Impulsivity critically relates to many psychiatric disorders. Given the multifaceted construct that impulsivity represents, defining core aspects of impulsivity is vital for the assessment and understanding of clinical conditions. Choice impulsivity (CI), involving the preferential selection of smaller sooner rewards over larger later rewards, represents one important type of impulsivity. Method The International Society for Research on Impulsivity (InSRI) convened to discuss the definition and assessment of CI and provide recommendations regarding measurement across species. Results Commonly used preclinical and clinical CI behavioral tasks are described, and considerations for each task are provided to guide CI task selection. Differences in assessment of CI (self-report, behavioral) and calculating CI indices (e.g., area-under-the-curve, indifference point, steepness of discounting curve) are discussed along with properties of specific behavioral tasks used in preclinical and clinical settings. Conclusions The InSRI group recommends inclusion of measures of CI in human studies examining impulsivity. Animal studies examining impulsivity should also include assessments of CI and these measures should be harmonized in accordance with human studies of the disorders being modeled in the preclinical investigations. The choice of specific CI measures to be included should be based on the goals of the study and existing preclinical and clinical literature using established CI measures.

Defining entertainment : an approach

Entertainment is a key cultural category. Yet the definition of entertainment can differ depending upon whom one asks. This article maps out understandings of entertainment in three key areas. Within industrial discourses, entertainment is defined by a commercial business model. Within evaluative discourses used by consumers and critics, it is understood through an aesthetic system that privileges emotional engagement, story, speed and vulgarity. Within academia, entertainment has not been a key organizing concept within the humanities, despite the fact that it is one of the central categories used by producers and consumers of culture. It has been important within psychology, where entertainment is understood in a solipsistic sense as being anything that an individual finds entertaining. Synthesizing these approaches, the authors propose a cross-sectoral definition of entertainment as ‘audience-centred commercial culture’.

Work Health and Safety Law and Policy

The third edition of Work Health and Safety Law and Policy continues to provide a plain English approach to explaining and analysing the law which regulates work health and safety in Australia. Providing broad coverage, this book focuses on the role that legal regulation plays in preventing work-related injury and disease, as well as the way in which the law contributes to rehabilitating and compensating injured and ill workers. This third edition focuses on the national model Work Health and Safety Bill 2009. The provisions of the model Bill are outlined, along with court decisions and other documentation that help interpret the provisions in new legislation enacting the model Bill. There is also a chapter in the book examining the national model Work Health and Safety Regulations 2011, and model codes of practice. The book includes three chapters on common law, statutory workers’ compensation provisions and rehabilitation. Tables summarising the key legal provisions of the major Australian Commonwealth, State and Territory workers’ compensation statutes have been updated and give quick and easy reference to points of legislation.

The legal concept of work-related injury and disease in Australian OHS and workers' compensation systems

This paper analyses the concept of ‘work-relatedness’ in Australian workers’ compensation and occupational health and safety (OHS) systems. The concept of work-relatedness is important because it is a crucial element circumscribing the limits of the protection afforded to workers under the preventative OHS statutes, and is a threshold element which has to be satisfied before an injured or ill worker can recover statutory compensation. While the preventive and compensatory regimes do draw on some similar concepts of work-relatedness, as this paper will illustrate, there are significant differences both between, and within, these regimes.

Foundations for the future : A long-term plan for Australian ecosystem science

Abstract: Australia’s ecosystems are the basis of our current and future prosperity, and our national well-being.A strong and sustainable Australian ecosystem science enterprise is vital for understanding and securing these ecosystems in the face of current and future challenges. This Plan defines the vision and key directions for a national ecosystem science capability that will enable Australia to understand and effectively manage its ecosystems for decades to come.The Plan’s underlying theme is that excellent science supports a range of activities, including public engagement, that enable us to understand and maintain healthy ecosystems.Those healthy ecosystems are the cornerstone of our social and economic well-being.The vision guiding the development of this Plan is that in 20 years’ time the status of Australian ecosystems and how they change will be widely reported and understood, and the prosperity and well-being they provide will be secure. To enable this, Australia’s national ecosystem science capability will be coordinated, collaborative and connected.The Plan is based on an extensive set of collaboratively generated proposals from national town hall meetings that also formthe basis for its implementation. Some directions within the Plan are for the Australian ecosystem science community itself to implement, others will involve the users of ecosystem science and the groups that fund ecosystem science.We identify six equal priority areas for action to achieve our vision: (i) delivering maximum impact for Australia: enhancing relationships between scientists and end-users; (ii) supporting long-termresearch; (iii) enabling ecosystem surveillance; (iv) making the most of data resources; (v) inspiring a generation: empowering the public with knowledge and opportunities; (vi) facilitating coordination, collaboration and leadership. This shared vision will enable us to consolidate our current successes, overcome remaining barriers and establish the foundations to ensure Australian ecosystem science delivers for the future needs of Australia..

The plasticity of NBS resistance genes in sorghum is driven by multiple evolutionary processes

Background Increased disease resistance is a key target of cereal breeding programs, with disease outbreaks continuing to threaten global food production, particularly in Africa. Of the disease resistance gene families, the nucleotide-binding site plus leucine-rich repeat (NBS-LRR) family is the most prevalent and ancient and is also one of the largest gene families known in plants. The sequence diversity in NBS-encoding genes was explored in sorghum, a critical food staple in Africa, with comparisons to rice and maize and with comparisons to fungal pathogen resistance QTL. Results In sorghum, NBS-encoding genes had significantly higher diversity in comparison to non NBS-encoding genes and were significantly enriched in regions of the genome under purifying and balancing selection, both through domestication and improvement. Ancestral genes, pre-dating species divergence, were more abundant in regions with signatures of selection than in regions not under selection. Sorghum NBS-encoding genes were also significantly enriched in the regions of the genome containing fungal pathogen disease resistance QTL; with the diversity of the NBS-encoding genes influenced by the type of co-locating biotic stress resistance QTL. Conclusions NBS-encoding genes are under strong selection pressure in sorghum, through the contrasting evolutionary processes of purifying and balancing selection. Such contrasting evolutionary processes have impacted ancestral genes more than species-specific genes. Fungal disease resistance hot-spots in the genome, with resistance against multiple pathogens, provides further insight into the mechanisms that cereals use in the “arms race” with rapidly evolving pathogens in addition to providing plant breeders with selection targets for fast-tracking the development of high performing varieties with more durable pathogen resistance.

CoWs, Google and online possibilities : creating digital posters to enhance student engagement

A new Bachelor of Science (BSc) course was introduced at Queensland University of Technology (QUT) in 2013 and focused on inquiry-based, collaborative and active learning. Two of the first year units required that students carry out a group poster assessment task. This poster provides a preliminary evaluation from an academic staff perspective of the assessment approach used, whereby students created digital posters to utilise the affordances of new learning spaces. The digital posters approach was first introduced to a group of academic staff from the Science and Engineering Faculty (SEF) in 2012 during a professional development program to explicitly develop skills and shared understandings of teaching in collaborative learning spaces (Steel & Andrews, 2012). Considerations were given to the pedagogical requirements of a poster assessment task, the affordances of the learning space and an identification of possible benefits of using Google Sites to create digital posters. Positive feedback from this group (as highlighted in the quotes shown) and subsequent approval from unit coordinators for two of the new first year BSc units meant that the approach was adopted for Semester 1, 2013 with approximately 360 students in each unit.

Board monitoring and the balanced scorecard in nonprofits : challenges in realising potential

Directors of nonprofits in most countries have legal responsibility for monitoring organisational performance (Brody 2010), although there is typically little guidance on how this should occur. The balanced scorecard (BSC) (Kaplan & Norton, 1996, 2001) potentially provides boards with a monitoring tool (Kaplan $ Norton, 2006; Lorsch, 2002). The BSC is intended to help integrate performance measurement, performance management and strategy implmentation (Kaplan 2009). The scorecards is balanced in that it should incorporate both financial and non-financial measures, external and internal perspectives, short and long-term objectives and both lagging and leading indicators. It is a relatively simple tool, but with potentially profound implications for directing board attention and sbusequent action (Ocasio, 1997; Salterio, 2012).

An SECM study on the influence of cationic, membrane-active peptides on a gold-supported self-assembled monolayer

The influence of the membrane active peptides, Tat44–57 (activator in HIV-1) and melittin (active content of bee venom), on self-assembled monolayers of 6-mercaptohexanoic acid (MHA) on gold electrodes has been studied with scanning electrochemical microscopy (SECM). It was found that MHA, when deprotonated at physiological pH, significantly affected the relative rates of electron transfer between the [Fe(CN)6]4− solution based mediator and the underlying gold electrode, predominantly by the electrostatic interaction between the mediator and MHA. Upon the introduction of Tat44–57 ormelittin to the electrolyte, the relative rate of electron transfer through the MHA layer could be increased or decreased depending on the mediator used. However, in all cases it was found that these peptides have the ability to be incorporated into synthetic SAMs, which has implications for future electrochemical studies carried out using cell mimicking membranes immobilised on such layers.

Job embeddedness and the importance of retaining small firm employees

Small firms identify retention of staff as a significant problem. Voluntary turnover of talented staff can be costly, especially in small firms where there are few slack resources. However, there is scant research on retention in small firms. We use the concept of Job Embeddedness to understand why small firm employees stay. The concept refers to the totality of forces that embed employees in their jobs and it consists of three dimensions: fit, links, and sacrifice. Seven propositions are outlined comparing the ways fit, links and sacrifice might play out for small and large firm employees. Through testing these propositions small firm owner-managers may have a better understanding of what can be done to retain employees and maintain firm performance.