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Aspects of testing tendon supports for strength, effective installation, and performance in different ground formation
No full textDifferent methods and techniques are reported in testing several types of tendons including solid rebars and cable bolts to evaluate their strength and performances in various rock formations. Most reported studies are laboratory-based, enhanced occasionally with numerical studies. Moreover, some tests are also carried out in situ to verify test results obtained from laboratory studies. The laboratory strength studies involved both push and pull testing, single and double shear testing of solid rebar, fiberglass rods, and cable bolts using different grout types installed in composite mediums of varied strength. Several challenges are faced when undertaking these various tests. These challenges may contribute to inconsistencies in the test results caused by various parameters, which are recognized, and the findings of these studies are examined and reported. This paper highlights a range of factors that influence tendon system performance based solely on two decades of tendon research by the rock mechanics group of the School of Civil, Mining, Environmental and Architectural Engineering, the University of Wollongong to draw the attention of the researcher on the importance of these factors and their influence in the real installation environment
A simulation model to access the impact of underground coal mine logistics strain on an operation
No full textA novel approach has been developed to strategically identify logistical bottlenecks and the impacts that mine planning parameters might have on these at any point in time throughout life of a mine plan. An XPAC-based model is employed at a macroscopic level to understand trends and shifts in logistical strain for a timeframe up to the entire life of mine. However, on a day-to-day basis the XPAC-based model cannot, at a very detailed level, provide information to analyse if logistical strain can be alleviated through finer adjustments. The finer adjustments that can be identified and rectified, can be determined using a discrete simulation FlexSim model. The paper presents details of the FlexSim discrete simulation model and its applications
Active ultrasonic monitoring of damage progression in coal under uniaxial compression
No full textCoal burst is a sudden and violent failure resulting from the formation and accumulation of microcracks caused by high overburden stresses, posing a significant safety risk to underground mining operations. Conventional stress-strain methods, often used for fracture assessment, are prone to subjectivity and errors, especially in highly fractured coal samples. This study investigates the feasibility of utilising ultrasonic through-transmission techniques as an alternative approach to determine the crack damage stress thresholds for coal. During uniaxial compression, changes in ultrasonic wave amplitude, wave velocity, dominant frequency, and Root-Mean-Square Voltage (VRMS) are actively monitored using 1 MHz and 100 kHz excitation frequencies. Distinct characteristics of the transmitted waveform were observed, marked by pronounced attenuation, reduced transmission velocity and a lower dominant frequency. Both excitation frequencies yielded significant insights when examining velocity changes during loading, with the highest velocity observed near the crack initiation stress threshold. In terms of amplitude, VRMS, and dominant frequency changes, the 1 MHz excitation proves to be more effective for coal specimens, displaying a consistent trend across all three samples, enabling the identification of crack closure, crack initiation and crack damage stress thresholds
New Directions in the Petasis-borono-Mannich reaction: Application of Organocatalysis and Allyl- and Crotylboronates for the Enantio- and Diastereoselective Synthesis of 1,2-Fluoroamines and 1,2-Amino Alcohols
No full textThe Petasis-borono-Mannich (PBM) reaction has been shown to be effective for the synthesis of chiral small molecules as well as polyhydroxylated alkaloids and heterocycles. However, there is very limited literature surrounding the use of allylboronates in the PBM reaction. In addition, most PBM reactions use chiral pool materials as a source of α-heteroatom aldehydes, rather than a more general method. Development of both these areas in the PBM reaction would enable a more versatile synthesis of alkaloid-like skeletons than is described in current literature. In this Thesis, organocatalysis was used to synthesise chiral α-heteroatom aldehydes according to literature procedures, which were then used as substrates in the PBM reaction with primary amines and allyl or crotylboronates, producing 1,2-fluoroamines or free or O-protected 1,2-amino alcohols with high diastereoselectivity and enantiopurity. These structures could then be transformed into heterocyclic derivatives in few subsequent steps. This work demonstrates a straightforward and versatile method of synthesis of alkaloid-like compounds with high structural complexity
Mindfulness and Imagery Enhanced Behavioural Parent Training: A Natural Evolution in Parenting Interventions
No full textMany parents feel overwhelmed by challenging child behaviours and multiple demands and seek assistance from parenting interventions. Behavioural parent training (BPT) has represented the gold standard treatment since the 1970s. However, half of parents disengage from BPT, with higher drop-out among socially-disadvantaged families. There is a need for evolution. The five studies within this thesis used a mixed methods approach to examine whether integrating mindfulness and imagery into existing BPT programs, via the 8-week Confident Carers Cooperative Kids (CCCK) group program, could meet a wider sociodemographic of family needs
Fire severity and forest flammability feedbacks in southeast Australia
No full textFire regimes are complex, with multiple components, drivers, and interactions, yet many studies of fire focus on the behaviour or impact of a single fire event or one component of the fire regime, usually fire frequency. Fire severity has recently been gaining traction as an important component of the fire regime to study. Fire severity is the impact of a fire on the landscape, specifically the physical consumption and scorching of vegetation. This results in structural changes to the vegetation as differential recovery mechanisms occur. Fire behaviour is also affected by the structure of the vegetation, or fuel, that is being burned, so it is likely that the severity of a fire is affected by the characteristics of the fire preceding it. There have been studies done examining this concept in North America, but little has been done in Australia, so in this thesis I ask the question: How do the eucalypt forests of southeast Australia respond to different levels of fire severity, and how does the subsequent fuel structure affect the severity of the next fire? To answer this question, the key aims of this thesis were to: 1) investigate the potential for a positive fire severity feedback continuing through a sequence of three overlapping fires (Chapter 2), 2) determine the effect of fire severity and prior fire history on the structure of resprouting eucalypt forests (Chapter 3), 3) investigate the structural differences in dry sclerophyll forests at three different times since the last fire (Chapter 4), and 4) determine how the severity of the 2019-20 fires in NSW was affected by the severity and type of past fires (Chapter 5)
Toward a Pixelated Solid State Detector for In-Vivo Dosimetry in Radiotherapy
No full textA large area pixelated silicon array detector named \MP987" has been developed for in-vivo dosimetry. The detector was developed to overcome the non-water equivalent response of EPID (Electronic Portal Imaging Device) dosimetry systems, due to the shortfalls of the extensive corrections required. The detector, readout system and software have all been custom designed and operate independently from the linac. The MP987 array is secured directly above the EPID, to be used in combination with the 6 MV imaging system. During the course of this thesis many aspects of in-vivo dosimetry were looked at, including: electrical and dosimetric characteristics of silicon diodes, feasibility of a dual detector system, angular dependence of silicon and synthetic diamond detectors and the suitability of different detector readout systems for multichannel arrays in external beam radiotherapy. In the final chapter of this thesis dosimetry characterisation measurements of percentage depth dose (PDD), dose rate dependence, radiation damage, output factors (OF), profile measurements, linearity and uniformity were performed with the MP987. Additionally, the first pre-clinical tests with this novel detector are presented, including, a transit dosimetry characterization and a collapsed IMRT (intensity modulated radiation therapy) study. Both PDD and OF measurements had a percentage difference of less than 2.5% to the reference detector. A maximum change in sensitivity of 4.3 ± 0.3% was observed after 30 kGy of gamma accumulated dose. Transit dosimetry measurements through a homogeneous phantom had a measured dose within the uncertainty of the TPS calculations, for field sizes between 3 × 3 cm2 and 10 × 10 cm2. A four-fraction collapsed IMRT plan on a lung phantom had absolute dose pass fractions between the MP987 and TPS (treatment planning system) from 94.2% to 97.4%, with a 5%/5 mm criteria. The ability to accurately measure dose at a transit level, without the need for correction factors derived from extensive commissioning data collection procedures, makes the MP987 a viable alternative to the EPID for in-vivo dosimetry. This MP987 is this first of its kind to be successfully developed specifically for a dual detector application
Homeopathy and biomedicine: Learning from conflict models
No full textTwo healthcare models, biomedicine and homeopathy, have offered contrasting perspectives and competed for patients for more than two hundred years. Biomedicine is considered the dominant modality in the Western world. Nevertheless, it is criticised, both from within and outside, for using unscientific methods and life-threatening procedures. To maintain its position, proponents of this approach have developed and put into action a variety of tactics. In contrast, homeopathy is struggling to maintain a mainstream position in health care (throughout this thesis, I have used the words 'health care' when referring to a noun and 'healthcare' when referring to an adjective). Defenders of homeopathy have sought to find recognition or acceptance from proponents of biomedicine. Even after accommodating the requests of advocates of biomedicine, homeopathy has remained marginalised. If the relationship between these two approaches to healthcare is thought of as a conflict, then it is plausible that insights can be gained from using conflict models. Gandhi, Machiavelli and Voss offer three dramatically different perspectives on resolving conflicts. This thesis examines the historical and contemporary conflict between homeopathy and biomedicine through these three lenses. It analyses what has happened and makes suggestions for how homeopathy and biomedicine might resolve their conflict
Pronunciation pedagogy in English as a foreign language teacher education programs in Vietnam
No full textPronunciation has gained significant attention in the field of English language teaching, with recent studies examining pronunciation representation in textbooks, classroom practices, teachers’ beliefs, and learners’ perceptions. However, research into teachers learning to teach English pronunciation is only beginning to emerge. The current study extends this line of enquiry by investigating the preparation of 20 Vietnamese English teachers to teach pronunciation. The study also examined the teachers’ perceptions of how Vietnamese teacher education could further assist teachers in teaching pronunciation. Qualitative data sources included academic transcripts, a questionnaire, and individual semi-structured interviews to examine the teacher-participants’ pronunciation pedagogy training and their beliefs about effective pronunciation teacher preparation. The findings showed that the teachers were insufficiently trained but reported being confident in their ability to teach English pronunciation. The participants also proposed several changes to be made to Vietnamese English teacher education programs for teachers to teach pronunciation more effectively
Key district heating technologies for building energy flexibility: A review
No full textIn the background of the continued integration of renewable energy sources (RES) and the increasing flexibility on the demand side, the diversity and complexity of new technologies for heating present increased challenges for design and operation of district heating systems (DHS). This work first reviews the progress of the new generation of DHS, followed by providing an overview of investigations on building energy flexibility in the field of heating, with a focus on the characterization and quantification of energy flexibility, the realization of thermal flexibility, and the use of building thermal mass in demand side management (DSM). Different technologies were categorized and summarized according to the composition of the new generation of DHS. Control strategies such as model predictive control were also examined. In particular, the concept of building thermal battery is used to analyze buildings or prosumers thermal energy flexibility. Finally, new elements of DHS development and potential challenges were discussed