Zernike radial slope polynomials for wavefront reconstruction and refraction

Ophthalmic wavefront sensors typically measure wavefront slope, from which wavefront phase is reconstructed. We show that ophthalmic prescriptions (in power-vector format) can be obtained directly from slope measurements without wavefront reconstruction. This is achieved by fitting the measurement data with a new set of orthonormal basis functions called Zernike radial slope polynomials. Coefficients of this expansion can be used to specify the ophthalmic power vector using explicit formulas derived by a variety of methods. Zernike coefficients for wavefront error can be recovered from the coefficients of radial slope polynomials, thereby offering an alternative way to perform wavefront reconstruction.

Application of electrical resistivity method to detect deep cracks in unsaturated residual soil slope

Crack is a significant influential factor in soil slope that could leads to rainfall-induced slope instability. Existence of cracks at soil surface will decrease the shear strength and increase the hydraulic conductivity of soil slope. Although previous research has shown the effect of surface-cracks in soil stability, the influence of deep-cracks on soil stability is still unknown. The limited availability of deep crack data due to the difficulty of effective investigate methods could be one of the obstacles. Current technology in electrical resistivity can be used to detect deep-cracks in soil. This paper discusses deep cracks in unsaturated residual soil slopes in Indonesia using electrical resistivity method. The field investigation such as bore hole and SPT tests was carried out at multiple locations in the area where the electrical resistivity testing have been conducted. Subsequently, the results from bore-hole and SPT test were used to verify the results of the electrical resistivity test. This study demonstrates the benefits and limitations of the electrical resistivity in detecting deep-cracks in a residual soil slopes.

Characteristics of modal sound radiation of finite cylindrical shells

Characteristics of modal sound radiation of finite cylindrical shells are studied using finite element and boundary element methods in this paper. In the low frequency range, modal radiation efficiencies of finite cylindrical shells are found to asymptotically approach those of the corresponding infinite cylindrical shell when structural trace wavelengths of the cylindrical shells are greater than the acoustic wavelength. Modal radiation efficiencies for each group of modes having the same circumferential modal index decrease as the axial modal index increases. They converge to each other when the axial trace wavelength is much greater than the circumferential trace wavelength. The mechanism leading to lower radiation efficiency of modes with higher circumferential modal index of short cylinders is explained. Similar to those of flat plate panels, change in slope or waviness is observed in modal radiation efficiency curves of modes with higher order axial modal index at medium frequencies. This is attributed to the interference of sound radiated by neighbouring vibrating cells when the distance between nodal lines of a vibrating mode is in the same order or smaller than the acoustic wavelength. Effects of the internal sound field on modal radiation efficiencies of a finite open-end cylinder are discussed.

The Wood Royal Commission : a case study in the slippery slope from unethical conduct to criminal acts

Over the last two and a half decades, corruption in the police service in Australia has come under increased official and public scrutiny. Numerous scandals involving police officers has caused concerned about the integrity and ethics within the Police Service. This paper examines the Wood Royal Commission, specifically looking at testimony from Trevor Haken. This paper provides insights into the nature of police corruption as well as the process or ‘slippery slope’ corrupt officers go through. This paper also contributed to the existing literature by providing knowledge into the types of corruption used by police officers in real-life situations, and deepening understanding of how corruption emerges and why. It specifically confirms the literature on slippery slope arguments about police corruption and the role of trust in building a corrupt career. The paper contributes to the existing literature by providing insights into the nature of corruption used by police officers in real-life situations, and deepens the understanding of the process of corruption. The findings also contribute to our understanding that corruption is not just an individual incident but rather a result of reoccurring incidents that are generated by the nature of work, organizational structure and society in relation to corruption.

High load transit line passenger transmission and productiveness efficiencies

Performance of urban transit systems may be quantified and assessed using transit capacity and productive capacity in planning, design and operational management activities. Bunker (4) defines important productive performance measures of an individual transit service and transit line, which are extended in this paper to quantify efficiency and operating fashion of transit services and lines. Comparison of a hypothetical bus line’s operation during a morning peak hour and daytime hour demonstrates the usefulness of productiveness efficiency and passenger transmission efficiency, passenger churn and average proportion line length traveled to the operator in understanding their services’ and lines’ productive performance, operating characteristics, and quality of service. Productiveness efficiency can flag potential pass-up activity under high load conditions, as well as ineffective resource deployment. Proportion line length traveled can directly measure operating fashion. These measures can be used to compare between lines/routes and, within a given line, various operating scenarios and time horizons to target improvements. The next research stage is investigating within-line variation using smart card passenger data and field observation of pass-ups. Insights will be used to further develop practical guidance to operators.

High load transit line passenger transmission and productiveness efficiencies

Performance of urban transit systems may be quantified and assessed using transit capacity and productive capacity in planning, design and operational management activities. Bunker (4) defines important productive performance measures of an individual transit service and transit line, which are extended in this paper to quantify efficiency and operating fashion of transit services and lines. Comparison of a hypothetical bus line’s operation during a morning peak hour and daytime hour demonstrates the usefulness of productiveness efficiency and passenger transmission efficiency, passenger churn and average proportion line length traveled to the operator in understanding their services’ and lines’ productive performance, operating characteristics, and quality of service. Productiveness efficiency can flag potential pass-up activity under high load conditions, as well as ineffective resource deployment. Proportion line length traveled can directly measure operating fashion. These measures can be used to compare between lines/routes and, within a given line, various operating scenarios and time horizons to target improvements. The next research stage is investigating within-line variation using smart card passenger data and field observation of pass-ups. Insights will be used to further develop practical guidance to operators.

Effects of slope inclination on the rain-induced instability of embankment slopes

Rainfall has been identified as one of the main causes for embankment failures in areas where high annual rainfall is experienced. The inclination of the embankment slope is important for its stability during rainfall. In this study, instrumented model embankments were subjected to artificial rainfalls to investigate the effects of the slope inclination on their stability. The results of the study suggested that when the slope inclination is greater than the friction angle of the soil, the failure is initiated by the loss of soil suction and when it is smaller than the friction angle of the soil, the failure is initiated by the positive pore water pressure developed at the toe of the slope. Further, slopes become more susceptible to sudden collapse during rainfall as the slope angle increases.

A method for predicting rain-induced instability of an individual slope

Awareness to avoid losses and casualties due to rain-induced landslide is increasing in regions that routinely experience heavy rainfall. Improvements in early warning systems against rain-induced landslide such as prediction modelling using rainfall records, is urgently needed in vulnerable regions. The existing warning systems have been applied using stability chart development and real-time displacement measurement on slope surfaces. However, there are still some drawbacks such as: ignorance of rain-induced instability mechanism, mislead prediction due to the probabilistic prediction and short time for evacuation. In this research, a real-time predictive method was proposed to alleviate the drawbacks mentioned above. A case-study soil slope in Indonesia that failed in 2010 during rainfall was used to verify the proposed predictive method. Using the results from the field and laboratory characterizations, numerical analyses can be applied to develop a model of unsaturated residual soils slope with deep cracks and subject to rainwater infiltration. Real-time rainfall measurement in the slope and the prediction of future rainfall are needed. By coupling transient seepage and stability analysis, the variation of safety factor of the slope with time were provided as a basis to develop method for the real-time prediction of the rain-induced instability of slopes. This study shows the proposed prediction method has the potential to be used in an early warning system against landslide hazard, since the FOS value and the timing of the end-result of the prediction can be provided before the actual failure of the case study slope.

Creating efficiencies in teaching : where are the right resources when you need them?

Early career engineering academics are encouraged to join and contribute to established research groups at the leading edge of their discipline. This is often facilitated by various staff development and support programs. Given that academics are often appointed primarily on the basis of their research skills and outputs, such an approach is justified and is likely to result in advancing the individual academic’s career. It also enhances their capacity to attract competitive research funding, while contributing to the overall research performance of their institution, with further potential for an increased share of government funding. In contrast, there is much less clarity of direction or availability of support mechanisms for those academics in their role as teachers. Following a general induction to teaching and learning at their institution, they would commonly think about preparing some lecture materials, whether for delivery in a face-to-face or on-line modality. Typically they would look for new references and textbooks to act as a guide for preparing the content. They would probably find out how the course has been taught before, and what laboratory facilities and experiments have been used. In all of these and other related tasks, the majority of newly appointed academics are guided strongly by their own experiences as students, rather than any firm knowledge of pedagogical principles. At a time of increased demands on academics’ time, and high expectations of performance and productivity in both research and teaching, it is essential to examine possible actions to support academics in enhancing their teaching performance in effective and efficient ways. Many resources have been produced over the years in engineering schools around the world, with very high intellectual and monetary costs. In Australia, the last few years have seen a surge in the number of ALTC/OLT projects and fellowships addressing a range of engineering education issues and providing many resources. There are concerns however regarding the extent to which these resources are being effectively utilised. Why are academics still re-inventing the wheel and creating their own version of teaching resources and pedagogical practice? Why do they spend so much of their precious time in such an inefficient way? A symposium examining the above issues was conducted at the AAEE2012 conference, and some pointers to possible responses to the above questions were obtained. These are explored in this paper and supplemented by the responses to a survey of a group of engineering education leaders on some of the aspects of these research questions. The outcomes of the workshop and survey results have been analysed in view of the literature and the ALTC/OLT sponsored learning and teaching projects and resources. Other factors are discussed, including how such resources can be found, how their quality might be evaluated, and how assessment may be appropriately incorporated, again using readily available resources. This study found a strong resonance between resources reuse with work on technology acceptance (Davis, 1989), suggesting that technology adoption models could be used to encourage resource sharing. Efficient use of outstanding learning materials is an enabling approach. The paper provides some insights on the factors affecting the re-use of available resources, and makes some recommendations and suggestions on how the issue of resources re-use might be incorporated in the process of applying and completing engineering education projects.

High-load transit line passenger transmission and productiveness efficiencies

Performance of urban transit systems may be quantified and assessed using transit capacity and productive capacity in planning, design and operational management activities. Bunker (4) defines important productive performance measures of an individual transit service and transit line, which are extended in this paper to quantify efficiency and operating fashion of transit services and lines. Comparison of a hypothetical bus line’s operation during a morning peak hour and daytime hour demonstrates the usefulness of productiveness efficiency and passenger transmission efficiency, passenger churn and average proportion line length traveled to the operator in understanding their services’ and lines’ productive performance, operating characteristics, and quality of service. Productiveness efficiency can flag potential pass-up activity under high load conditions, as well as ineffective resource deployment. Proportion line length traveled can directly measure operating fashion. These measures can be used to compare between lines/routes and, within a given line, various operating scenarios and time horizons to target improvements. The next research stage is investigating within-line variation using smart card passenger data and field observation of pass-ups. Insights will be used to further develop practical guidance to operators.

Driving whole-of-life efficiencies through BIM and procurement

Building Information Modelling (BIM) is a digital process that encompasses all aspects, disciplines and systems of built assets within a single virtual model. This allows stakeholders to collaborate more accurately and efficiently than with traditional processes. Case study 1 Design: New Generation Rollingstock Maintenance Centre, Queensland. Case Study 2 Construction: Perth Children's Hospital, Western Australia. Case Study 3 Asset Management: Sydney Opera House, New South Wales. This project sought to provide the built environment industry with a framework to measure and maximize benefits from implementing BIM across the life-cycle phases of a built asset.

On the efficiency of impingers with fritted nozzle tip for collection of ultrafine particles

The aim of this study was to determine the collection efficiency of ultrafine particles into an impinger fitted with a fritted nozzle tip as a means to increase contact surface area between the aerosol and the liquid. The influence of liquid sampling volume, frit porosity and the nature of the sampling liquid was explored and it was shown that all impact on the collection efficiency of particles smaller than 220 nm. Obtained values for overall collection efficiency were substantially higher (~30–95%) than have been previously reported, mainly due to the high deposition of particles in the fritted nozzle tip, especially in case of finer porosity frits and smaller particles. Values for the capture efficiency of the solvent alone ranged from 20 to 45%, depending on the type and the volume of solvent. Additionally, our results show that airstream dispersion into bubbles improves particle trapping by the liquid and that there is a difference in collection efficiencies based on the nature and volume of the solvent used.

Sound radiation characteristics of a box-type structure

The finite element and boundary element methods are employed in this study to investigate the sound radiation characteristics of a box-type structure. It has been shown [T.R. Lin, J. Pan, Vibration characteristics of a box-type structure, Journal of Vibration and Acoustics, Transactions of ASME 131 (2009) 031004-1–031004-9] that modes of natural vibration of a box-type structure can be classified into six groups according to the symmetry properties of the three panel pairs forming the box. In this paper, we demonstrate that such properties also reveal information about sound radiation effectiveness of each group of modes. The changes of radiation efficiencies and directivity patterns with the wavenumber ratio (the ratio between the acoustic and the plate bending wavenumbers) are examined for typical modes from each group. Similar characteristics of modal radiation efficiencies between a box structure and a corresponding simply supported panel are observed. The change of sound radiation patterns as a function of the wavenumber ratio is also illustrated. It is found that the sound radiation directivity of each box mode can be correlated to that of elementary sound sources (monopole, dipole, etc.) at frequencies well below the critical frequency of the plates of the box. The sound radiation pattern on the box surface also closely related to the vibration amplitude distribution of the box structure at frequencies above the critical frequency. In the medium frequency range, the radiated sound field is dominated by the edge vibration pattern of the box. The radiation efficiency of all box modes reaches a peak at frequencies above the critical frequency, and gradually approaches unity at higher frequencies.

BIM – implications for government

As ‘The Architect’s Handbook of Professional Practice’ (cited by Riskus (2007) suggests, Building Information Modelling, or BIM, is “the use of virtual building information models to develop building design solutions, design documentation, and to analyse construction processes”. We would suggest such a definition, while useful, should be extended to include the operational phases of built assets (such as maintenance and decommissioning), and also be applied to the whole area of infrastructure. As a set of technologies, BIM holds promise to deliver benefits for the property, construction, and infrastructure management industries – particularly improved efficiencies and effectiveness through enhanced collaboration at all stages of the construction cycle. There are several important qualifiers, barriers, enablers, and some disadvantages with this suite of technologies. This report outlines the costs and benefits enablers and barriers associated with BIM, and makes suggestions about how these issues may be addressed.