A high cell count cascade full bridge converter for wide bandwidth ultrasonic transducer excitation

A nine level modular multilevel cascade converter (MMCC) based on four full bridge cells is shown driving a piezoelectric ultrasonic transducer at 71 and 39 kHz, in simulation and experimentally. The modular cells are small stackable PCBs, each with two fully integrated surface mount 22 V, 40 A MOSFET half-bridge converters, and include all control signal and power isolation. In this work, the bridges operate at 12 V and 384 kHz, to deliver a 96 Vpp 9 level waveform with an effective switching frequency of 3 MHz. A 9 pH air cored inductor forms a low pass filter in conjunction with the 3000 pF capacitance of the transducer load. Eight equally phase-displaced naturally sampled pulse width modulation (PWM) drive signals, along with the modulating sinusoid, are generated using phase accumulation techniques in a dedicated FPGA. Experimental time domain and FFT plots of the multilevel and transducer output waveforms are presented and discussed.

Developments in mud filtration technology in the sugarcane industry

Dirt collected with sugarcane is processed and separated from the juice in the sugar factory by filtration equipment for return to the cane fields. New technologies over the past decade have enabled performance improvements to be obtained for this key unit operation. Filter mud product still contains a reasonable amount of sugar and the transportation of high moisture mud product has considerable cost. Australia’s traditional approach has been to use Rotary Vacuum Filters for processing and separating mud and other impurities from juice, but in recent years there has been interest in reducing sugar losses and transportation costs through utilisation of new technologies such as Horizontal Bed Filters, Vacuum Belt Press Filters, Membrane Press Filters and Centrifuges. Increasingly, these alternative equipment are being installed in new factories. This chapter describes the general principles of mud filtration theory and mud conditioning followed by a detailed description and review of the various filtration technologies and analysis of the relative merits associated with the equipment.

Studying upper-limb kinematic using inertial sensors embedded in smartphones

Background: In recent years, there have been investigations concerning upper-limbs kinematics by various devices. The latest generation of smartphones often includes inertial sensors with subunits which can detect inertial kinematics. The use of smartphones is presented as a convenient and portable analysis method for studying kinematics in terms of angular mobility and linear acceleration Objective: The aim of this study was to study humerus kinematics through six physical properties that correspond to angular mobility and acceleration in the three axes of space, obtained by a smartphone. Methods: This cross-sectional study recruited healthy young adult subjects. Descriptive and anthropometric independent variables related to age, gender, weight, size, and BMI were included. Six physical properties were included corresponding to two dependent variables for each of three special axes: mobility angle (degrees) and lineal acceleration (meters/seconds2), which were obtained thought the inertial measurement sensor embedded in the iPhone4 smartphone equipped with three two elements for the detection of kinematic variables: a gyroscope and an accelerometer. Apple uses an LIS302DL accelerometer in the iPhone4. The application used to obtain kinematic data was xSensor Pro, Crossbow Technology, Inc., available at the Apple AppStore. The iPhone4 has storage capacity of 20MB. The data-sampling rate was set to 32 Hz, and the data for each analytical task was transmitted as email for analysis and postprocessing The iPhone4 was placed in the right half of the body of each subject located in the middle third of the humerus slightly posterior snugly secured by a neoprene fixation belt. Tasks were explained concisely and clearly. The beginning and the end were decided by a verbal order by the researcher. Participants were placed standing, starting from neutral position, performing the following analytical tasks: 180º right shoulder abduction (eight repetitions) and, after a break of about 3 minutes, 180º right shoulder flexion (eight repetitions). Both tasks were performed with the elbow extended, wrist in neutral position and the palmar area of the hand toward the midline at the beginning and end of the movement. Results: A total of 11 subjects (8 men, 3 woman) were measured, whose mean of age was 24.7 years (SD = 4.22 years) and their average BMI was 22.64 Kg/m2 (SD = 2.29 Kg/m2). The mean of angular mobility collected by the smartphone was bigger in pitch axis for flexion (= 157.28°, SD= 12.35°) and abduction (= 151.71°, SD= 9.70°). With regard to acceleration, the highest peak mean value was shown in the Y motion axis during flexion (= 19.5°/s2, SD = 0.8°/s2) and abduction (= 19.4°/s2, SD = 0.8°/s2). Also, descriptive graphics of analytical tasks performed were obtained. Conclusions: This study shows how humerus contributes to upper-limb motion and it identified movement patterns. Therefore, it supports smartphone as a useful device to analyze upper-limb kinematics. Thanks to this study it´s possible to develop a simple application that facilitates the evaluation of the patient.

A biomechanical study of spherical grip

Use of the hand is vital in working life due to the grabbing and pinching it performs. Spherical grip is the most commonly used, due to similarity to the gripping of a computer mouse. Knowledge of its execution and the involved elements is essential. Analysis of this exertion with surface electromyography devices (to register muscular activity) and accelerometer devices (to register movement values ) can provide multiple variables. Six subjects performed ball gripping and registered real-time electromyography (thenar region, hypothenar region, first dorsal interosseous, flexors of the wrist, flexor carpi ulnaris and extensors of the wrist muscles) and accelerometer (thumb, index, middle, ring, pinky and palm) values. The obtained data was resampled “R software” and processed “Matlab Script” based on an automatic numerical sequence recognition program. Electromyography values were normalized on the basis of maximum voluntary contraction, whilst modular values were calculated for the acceleration vector. After processing and analysing the obtained data and signal, it was possible to identify five stages of movement in accordance with the module vector from the palm. The statistical analysis of the variables was descriptive: average and standard deviations. The outcome variables focus on the variations of the modules of the vector (between the maximum and minimum values of each module and phase) and the maximum values of the standardized electromyography of each muscle. Analysis of movement through accelerometer and electromyography variables can give us an insight into the operation of spherical grip. The protocol and treatment data can be used as a system to complement existing assessments in the hand.

Muramidases found in the foregut microbiome of the Tammar wallaby can direct cell aggregation and biofilm formation

We describe here the role of muramidases present in clones of metagenomic DNA that result in cell aggregation and biofilm formation by Escherichia coli. The metagenomic clones were obtained from uncultured Lachnospiraceae-affiliated bacteria resident in the foregut microbiome of the Tammar wallaby. One of these fosmid clones (p49C2) was chosen for more detailed studies and a variety of genetic methods were used to delimit the region responsible for the phenotype to an open reading frame of 1425 bp. Comparative sequence analysis with other fosmid clones giving rise to the same phenotype revealed the presence of muramidase homologues with the same modular composition. Phylogenetic analysis of the fosmid sequence data assigned these fosmid inserts to recently identified, but uncultured, phylogroups of Lachnospiraceae believed to be numerically dominant in the foregut microbiome of the Tammar wallaby. The muramidase is a modular protein containing putative N-acetylmuramoyl--alanine amidase and an endo-β-N-acetylglucosaminidase catalytic module, with a similar organization and functional properties to some Staphylococcal autolysins that also confer adhesive properties and biofilm formation. We also show here that the cloned muramidases result in the production of extracellular DNA, which appears to be the key for biofilm formation and autoaggregation. Collectively, these findings suggest that biofilm formation and cell aggregation in gut microbiomes might occur via the concerted action of carbohydrate-active enzymes and the production of extracellular DNA to serve as a biofilm scaffold.

Reshaping housing using prefabricated systems

Prefabricated housing innovations have the potential to reduce the environmental impact of construction through improvements to efficiency and quality. The current paper presents a number of recommendations for increasing the adoption of prefabrication based on a review of published evidence. The recommendations consider multiple stakeholders including builders and other intermediaries, suppliers, end-users, as well as their interaction with the broader policy context and technical issues

Driver licensing experience of Korean Australian novice drivers

Graduated driver licensing has been shown to improve the safety of young drivers but relatively little is known about how well it works for drivers born in countries where the licensing system is less sophisticated. This research used Bronfenbrenner's ecological model to examine the driver licensing experience of Korean Australian young drivers using driver and parent focus groups and an online survey of drivers. Accumulating the required supervised driving was more difficult for international students than those living with parents and differences in road rules (particularly relating to seat belt use) between the countries exerted an important influence on behaviour.

Innovative design : developing strategies to improve developer attitudes to sustainable housing

The literature advocates more widespread adoption of a particular type of house – a manufactured high performance green house and/or house components (MHPGH) and this is the focus of the research proposal outlined in this conceptual paper. The aim of the current paper is to outline a robust program of work to improve adoption of MHPGH. The contribution of houses to climate change is investigated, the conservatism of the construction industry is documented, a conceptual framework through which to understand the problem is presented; a program of research to bring about change is outlined; and the benefits of doing so are summarised. The contribution of the paper is the presentation of novel theory and methods to address sustainability problems in the construction industry. Future work will involve execution of the proposal. A limitation of the paper is that the effectiveness of the proposed theory and methods are yet to be tested.

Non-wearing of adult seat belts in Australia: Where to next? [Austroads Publication No. AP-R346/09]

Seat belts are one of the most effective passive safety features in vehicles and there is a host of research literature attesting to the effectiveness of seat belts in protecting against death and injury. Even when use rates are high the potential gains in trauma reduction from further improvements in wearing rates are substantial. However, those currently most resistant to restraint use have also proven most difficult to target using conventional countermeasures. It is necessary to address the issues of non-wearing in order to achieve further gains in seat belt wearing. This study provide evidence-based recommendations for the way forward to tackle the problems of adult restraint non-use in light passenger vehicles in the short, medium and longer term in Australia. While there are substantial issues to be addressed for these groups, these are outside the scope of this study.

Cryptographic hash functions

Cryptographic hash functions are an important tool of cryptography and play a fundamental role in efficient and secure information processing. A hash function processes an arbitrary finite length input message to a fixed length output referred to as the hash value. As a security requirement, a hash value should not serve as an image for two distinct input messages and it should be difficult to find the input message from a given hash value. Secure hash functions serve data integrity, non-repudiation and authenticity of the source in conjunction with the digital signature schemes. Keyed hash functions, also called message authentication codes (MACs) serve data integrity and data origin authentication in the secret key setting. The building blocks of hash functions can be designed using block ciphers, modular arithmetic or from scratch. The design principles of the popular Merkle–Damgård construction are followed in almost all widely used standard hash functions such as MD5 and SHA-1.

Reshaping housing : the role of prefabricated systems

Prefabricated housing innovations have the potential to reduce the environmental impact of construction through improving efficiency and quality. The current paper systematically summarises the published evidence since 1990 that describes the barriers and drivers affecting the uptake of prefabricated housing innovations. These are discussed in relation to a ‘Project-Based Product Framework’ which considers multiple stakeholders including builders and other intermediaries, suppliers, end-users, the broader policy context and technical issues. The framework facilitated identification of central issues such as the prevalent business and cultural resistance associated with process changes; the potential for efficiency and quality improvements and cost savings; the simultaneous risks and benefits of close supplier-builder relationships, and negative user perceptions towards prefabricated houses. Though there is a lack of evidence regarding the effects of regulations and government policies on prefabrication uptake, there are indications of the positive potential of financial and social incentives. Directions for further research include understanding how to: manage the industry’s transition to prefabricated houses; appropriately compare prefabricated housing to traditional housing on cost, efficiency and quality measures; reconcile the differing perspectives of various stakeholders; quantify and identify the perspectives of the potential end-user population, and manage the interface between the emerging industry and information technology improvements.

Profiling the nature and context of the Australian prefabricated housing industry

The current state of the prefabricated housing market in Australia is systematically profiled, guided by a theoretical systems model. Particular focus is given to two original data collections. The first identifies manufacturers and builders using prefabrication innovations, and the second compares the context for prefabricated housing in Australia with that of key international jurisdictions. The results indicate a small but growing market for prefabricated housing in Australia, often building upon expertise developed through non-residential building applications. The international comparison highlighted the complexity of the interactions between macro policy decisions and historical influences and the uptake of prefabricated housing. The data suggest factors such as the small scale of the Australian market, and a lack of investment in research, development and training have not encouraged prefabrication. A lack of clear regulatory policy surrounding prefabricated housing is common both in Australia and internationally, with local effects in regards to home warranties and housing finance highlighted. Future research should target the continuing lack of consideration of prefabrication from within the housing construction industry, and build upon the research reported in this paper to further quantify the potential end user market and the continuing development of the industry.

What’s driving the uptake of prefabricated housing in Australia?

Prefabrication has been promoted as a means to improve the efficiency of the Australian house building industry. Issues affecting the uptake of prefabrication were identified through interviews with small and medium sized building companies. Prefabrication’s specific impact on housing construction and smaller organisations has not been frequently investigated. Similar past research has been conducted without the use of a clear theoretical grounding guiding the identification of relevant issues. The current study is guided by a combination of the Theory of Planned Behaviour (TPB) and the Technology Acceptance Model (TAM). This allowed the identification of a broad range of issues across attitudinal, normative, behavioural control and technology adaptation domains. Results revealed improved quality was often offset against practical cost implications. While a high quality of prefabricated products was reported, key technical challenges included coordinating the transporting of modules, and balancing standardisation and product flexibility. Resistance from traditional industry stakeholders regarding build methods, financing, and openness to encouraging prefabrication was commonly reported. The key role of government decision making in facilitating greater demand and competitiveness of prefabricated businesses in the consumer marketplace was also highlighted. Further research is currently being undertaken by the authors, which builds on the exploratory results of the current study through confirmatory, quantitative surveying.

Predicting Australian builders’ intentions to use prefabrication

This study presents the results of the first large scale survey of Australian builders’ beliefs about prefabrication, drawing on 454 surveys completed by representatives of building companies in Queensland and Western Australia. Previous literature has identified a number of broad themes affecting the uptake of prefabrication. The current study builds on this work by using a structured theoretical model based on the Theory of Planned Behaviour (TPB) and the Technology Acceptance Model (TAM), to further explore the specific factors influencing builders’ intentions to increase their use of prefabrication. Information was gathered concerning the characteristics of respondents in addition to three aims. The aims were: (1) To identify the relative importance of a number of key factors which may affect builders’ use of prefabrication, (2) To compare the characteristics of builders using various levels of prefabrication (including none), and; (3) To determine if a model based on the TPB, TAM, and other control variables can explain builders’ intentions to adopt prefabrication on their housing projects.

Measuring in-vehicle child comfort to study barriers to appropriate and correct use of restraints

Traffic crashes are the leading cause of death and injury among children aged between 4-14 years1,2 and premature graduation to adult seat belts2,3 and restraint misuse4 are common and known risk factors. Children are believed to prematurely graduate to adult belts and misuse the seat belt in booster seats if uncomfortable2,5,6. Although research has concentrated on educating parents and designing better restraints to reduce errors in use, comfort of the child in the restraint has not been studied. Currently there is no existing method for studying comfort in children in restraint systems, although self-report survey tools and pressure distribution mapping is commonly used to measure comfort among adult in vehicle seats. This poster presents preliminary results from work aimed at developing an appropriate method to measure comfort of children in vehicle restraint systems. The specific aims are to: 1. Examine the potential of using modified adult self-report/survey and pressure distribution mapping in children 2. Develop a video based, objective measure of comfort in children.