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Developing a fast and effective network free-speed calibration procedure for agent-based transport simulations
No full textAgent-based simulations play an essential role in transport planning. To ensure realistic and reliable outcomes, an accurate network model is essential. In this study, we propose a fast and effective network free-speed calibration procedure for agent-based transport simulation frameworks. To evaluate and quantify its performance, we implement the procedure in an agent-based transport simu?lation framework, MATSim. The results demonstrate that the proposed procedure effectively aligns the free-speed of the network with reference data. Moreover, it outperforms existing network calibration methods in output quality and computational efficiency. Specifically, the new approach further reduces the error statistics related to free-speed travel time by over 50% compared to existing methods. Additional experiments also reveal that the new network calibration procedure can still deliver good results even with limited reference data.</p
Communicating Australian cotton’s sustainable value in the cotton value chain
No full textPurposeThis qualitative study explores the dynamics of communicating Australian cotton’s on-farm sustainability to actors throughout global value chains. The research is guided by two objectives: first, to understand how sustainability in Australian cotton is perceived by value chain members, and second, to pinpoint strategies for cultivating a shared understanding of on-farm sustainability within the Australian cotton value chain (ACVC).Design/methodology/approachEmploying qualitative research methods, the study conducts interviews with 21 participants from two distinct ACVCs.FindingsEffectively communicating the sustainability of clothing fibre demands thoughtful consideration of how knowledge is translated from farmer to retailer. The diverse nature of cotton production practices leads to varied understandings of sustainability, making it challenging to establish a consistent narrative. The study found that clear information and visual storytelling of on-farm practices enhance stakeholders’ understanding. The use of complex technical information was a barrier to effective communication, and there was general scepticism among retailers regarding industry-funded sustainability credentials. These findings underscore the importance of building trust through two-way communication between retailers and farmers.Research limitations/implicationsThis study highlights the need for more collaborative efforts to foster a shared understanding of sustainability across the value chain. The findings of this study may not be broadly representative of the entire Australian or global cotton industry, but the depth of insights and methodological approach may be applied to other value chains.Originality/valueThis research advances the literature on sustainability communication in the context of fashion production and consumption. It takes a unique perspective by focussing on how sustainability is communicated by different stakeholders working with Australian cotton.</p
Susceptibility to cognitive biases in athlete-team selection
No full textHumans are not immune to cognitive biases in judgment and decision-making. However, little is known about cognitive biases (i.e., a departure from rationality in judgements and decision-making) involved in athlete-team selection by coaches or specialist selectors, which can have a major impact on the team's success. To provide further insight, our research explores the extent to which coaches/selectors perceive they are susceptible to cognitive bias. Twelve national-level coaches/selectors were interviewed (semi-structured) under an interpretive phenomenological research design. Using reflective thematic analysis of the data, we offer three main findings. First, coaches/selectors are susceptible to multi-causal cognitive biases in athlete-team selection. Second, the driving force behind such biases is a phenomenon known as “conflict in cognitive dissonance”. Third, such suboptimal behaviour is perpetuated by the coaches’/selectors’ “oversight of cognitive biases”. We offer a number of policy recommendations that promote effective and unbiased selection processes in sports (and more broadly in society), enhancing equity as well as performance excellence.</p
Propagation of Small Cracks Caused by Underloading in AA7050-T7451
No full textThe fatigue design and management of aircraft is essential to ensure they safely and economically achieve their designed service lives. However, despite over 100 years of research into fatigue crack growth there are still significant challenges to accurately predicting the fatigue life of components. As a result, all commercial and military aircraft types are required to undergo full scale fatigue tests whereby they are repeatedly loaded in a manner representative of flight. To account for the statistical scatter in crack growth, they are often subject to repeated loads equivalent to at least two lifetimes of the aircraft design life. This results in expensive and time-consuming testing. In addition, these tests often reveal unexpected fatigue issues with the initial aircraft design, resulting in costly redesign processes. These redesigns are necessary for ensuring the safety of the aircraft and will usually increase the economic life of the aircraft. Ideally, however, the initial crack growth predictions should be accurate enough not to require such redesigns.
Two reasons for this unpredictability include (i) the differences in the expected growth of small and long cracks, and (ii) the differences in the expected crack growth for constant amplitude (CA) and variable amplitude (VA) loading. It has been shown in many studies that small cracks, here defined as cracks less than 1 mm in length, will typically grow faster than expected compared to long cracks when subject to nominally identical stress intensity factor ranges. This means that the extensive crack growth data gathered from long crack tests during the past century cannot be directly used to predict small crack growth accurately. Additionally, it has been shown that coupons subject to VA loading, where loads are applied in a pseudorandom order, will nearly always experience faster crack growth than when the loads are applied in a blocked CA manner. As such, even when predicting long crack growth, where there is extensive historical data, if the sequence of the test loads is different to that in the prediction, then it is likely the results will deviate noticeably between the test and prediction.
The difficulty in the predictability of VA loading growth compared to CA loading growth comes from ‘history effects’ associated with the loading and the material. These history effects are often explained in the literature as being caused by material surrounding the fatigue crack being plasticly deformed from the previous loads. In the case of a large tensile load, the material around the crack tip is stretched more than for smaller loads. Once the load is relaxed, this stretched material no longer fits within its original volume around the crack tip, meaning that it must be compressed by the neighbouring, non-plastically deformed, material. This has the effect of superimposing a compressive stress on all bulk stresses at the crack tip. The opposite can occur if the crack tip remains open when a large compressive load is applied, resulting in the superimposition of tensile stresses. This means that the true stress range at the crack tip is constantly changing in the case of VA loading and can be quite different at the crack tip compared to the far field stress ranges being applied. This is one reason why the literature has found that using linear summation of damage without accounting for history effects can lead to vastly incorrect predictions of fatigue life.
The other above-stated reason for the unpredictability of fatigue crack growth rates stems from the small crack effect. This is a result of the fact that cracks will typically grow faster when they are small (shorter than 1 mm) compared to when they are long (greater than 1 mm), despite nominally identical crack tip stress intensity factor ranges being applied. This poses a problem for highly stressed structures, since they can often spend 70% or more of their lifespan in this small crack regime. This means that predictions made using long crack data can be highly unconservative. There are various reasons for this stated in the literature, including reduced crack closure, and a fundamental breakdown of the similitude concept that underpins linear elastic fracture mechanics. Regardless of the reason, this variation means that crack growth rate predictions of small cracks using the long crack data are typically slower than reality.
The focus of this thesis is on better quantifying and describe small fatigue crack growth. The material chosen for the experimental phase of this study is AA7050-T7451 and the focus of the study will be the effect that underloads have on the crack growth rate. These underloads are individual load cycles where the minimum applied load is lower than the surrounding loads. These underloads may have the effect of superimposing a tensile residual stress on the load cycles following their application. When these tensile residual stresses are considered in conjunction with the known faster small crack growth rates, highly unconservative predictions are often made when modelling such crack growth conditions. These unconservative predictions may be one reason for unexpected fatigue cracking that commonly occurs in full-scale test articles.
This study into underloads has had both a quantitative and qualitative focus. Firstly, multiple crack growth studies were conducted to gather data on crack growth rates of cracks in test coupons when subject to underloads. These underloads varied in magnitude, spacing, and consecutive number with the goal of understanding how each of these variables affected the proceeding crack growth rates. After the crack growth studies, detailed fractographic analysis was conducted to describe the fracture surface features common to underloads on both mating fracture surfaces. It was expected that these fractographic features would provide clues as to the underlying mechanisms driving the underload acceleration. In addition, a detailed study of the correlation between surface roughness and the growth associated with underload applications was made. This was examined since reduced surface roughness has been a quoted mechanism associated with underload acceleration reported in the literature.
The study conducted here ultimately quantified the amount that underloads accelerate fatigue crack growth of the subsequent load cycles for AA7050-T7451 under the loading conditions presented here. It showed that underload magnitude, spacing, and their consecutive number all play an important role in dictating the amount of acceleration that occurs. Additionally, fracture surface fissures were found to be a common feature that was evident on the fracture surface when underloads were applied at all studied crack lengths, indicating that further investigation of these features may be key to understanding the physical mechanisms behind the underload effect. It was also found that small scale systematic surface roughness had no clear correlation with the application of underloads, indicating that this was not an important mechanism behind the accelerative effects of the underloads.
The research presented here provides a step forward in our understanding of the role that underloads can have in small crack propagation. However, there is much scope for future research in this area, including investigating different materials, different cyclic load ratios, and further investigation of the potential underlying mechanisms that cause the underload accelerations. This will be discussed in more detail at the end of the thesis.</p
Devising an ethical death knock model: the role of preparations, precursors and professional identity in mitigating moral injury for journalists
No full textThis paper proposes a model for an ethical ‘death knock’, the practice by which a journalist approaches a bereaved family to write a story following a newsworthy death. The practice can cause journalists harm, sometimes as moral injury, which results from an ethical breach. Through a literature review and study of Australian journalists, a model of an ethical death knock has emerged that may mitigate moral injury. Elements were developed through analysis of journalists’ expression of how they could be better prepared (training, knowledge, advice, support), and what they perceived as the necessary precursors (conditions) for an ethical death knock (the capacity to act honestly, with respect and empathy, and make a personal approach in circumstances that are justified). The model creates conditions for an ethical death knock through alignment with, and valorisation of, the journalist’s sense of professional identity, which bolsters their resilience to moral injury. The model is underpinned by Bourdieusian field theory.</p
Decoding influencer authenticity: the CueSphere model of extrinsic cues
No full textPurpose This study aims to explore extrinsic cues and how they contribute to decoding the perceived authenticity of social media influencers in content co-creation within professional beauty services. Design/methodology/approachGrounded in attribution theory, the causes of social media influencer’s unobservable authenticity are attributed to extrinsic cues. This study delves into these extrinsic cues by conducting in-depth interviews and thematic analysis with 21 customers of professional service beauty brands. Findings This study introduces the CueSphere model for decoding the perceived authenticity of social media influencers, incorporating nine distinct extrinsic cues: five customer experience-related cues (i.e. source factors, comment valence, post-service effectiveness, experience alignment and customer materialism) and four collaborative brand-related cues (i.e. brand credibility, brand coolness, brand experience and influencer-owned brand). Practical implicationsThe CueSphere model guides service providers, marketing agencies and various stakeholders within the service marketing ecosystem to decode the perceived authenticity of social media influencers. Social implicationsThis study endorses ethical marketing and supports societal goals of body positivity and well-being by promoting authentic social media influencers. Originality/valueBuilding on attribution theory, this study discovers extrinsic cues (i.e. customer experience-related and collaborative brand-related cues) as a new avenue to decode the perceived authenticity of social media influencers in content co-creation within professional beauty services marketing. This study demonstrates that unlike product-based endorsements, where authenticity relates to an influencer’s honesty and expertise, decoding authenticity in service-based endorsements requires considering extrinsic cues from both the service brand and customer experiences. The CueSphere model offers nine distinct extrinsic cues to evaluate the perceived authenticity of social media influencers in shaping the servicescape atmosphere for minimally invasive cosmetic procedures.</p
Machine Learning Descriptors for CO2 Capture Materials
No full textThe influence of machine learning (ML) on scientific domains continues to grow, and the number of publications at the intersection of ML, CO2 capture, and material science is growing rapidly. Approaches for building ML models vary in both objectives and the methods through which materials are represented (i.e., featurised). Featurisation based on descriptors, being a crucial step in building ML models, is the focus of this review. Metal organic frameworks, ionic liquids, and other materials are discussed in this paper with a focus on the descriptors used in the representation of CO2-capturing materials. It is shown that operating conditions must be included in ML models in which multiple temperatures and/or pressures are used. Material descriptors can be used to differentiate the CO2 capture candidates through descriptors falling under the broad categories of charge and orbital, thermodynamic, structural, and chemical composition-based descriptors. Depending on the application, dataset, and ML model used, these descriptors carry varying degrees of importance in the predictions made. Design strategies can then be derived based on a selection of important features. Overall, this review predicts that ML will play an even greater role in future innovations in CO2 capture.</p
Refashioning Accelerating Circular Product Design at Scale: A Practical Guide
No full textThe Refashioning Circular Design Guide presents a practical and systematic approach to design for circularity in fashion. The Guide encourages a design practice that is centred around the regeneration of nature and natural systems through action. By extending the circular designer's remit to consider the lifecycle of a product, particularly the product’s quality and functionality and how the product will be used and disposed of, circular designers are empowered to go beyond minimising environmental impact to actively contribute to regenerating our world’s natural systems.</p
For a Safer Quảng Trị
No full textProject “For a Safer Quang Tri” is RENEW’s daring leap into the digital age, bringing the stark realities of unexploded ordnance clearance and mine risk education to life. This isn’t just about highlighting dangers; it’s a powerful stand against the inhumanity of war’s remnants, especially in these turbulent times when global tensions are at a breaking point.
Beyond connecting with the people of Quang Tri and peace advocates across Vietnam and beyond, the project aims to spark a global conversation for a safer, more compassionate world — one where inhumane weapons like cluster bombs are universally condemned and have no place.
This is an ambitious digital project yet, meticulously studying data from an extensive archive dating back to 1975 and transforming those numbers into impactful visualizations, content strategies, and UX/UI design.</p
Automotive PEM fuel cell catalyst layer degradation mechanisms and characterisation techniques, Part I: Carbon corrosion and binder degradation
No full textThis review comprehensively examines two major degradation mechanisms in Pt/C-based catalyst layers widely used in automotive polymer exchange membrane fuel cells: carbon corrosion and perfluorosulfonic acid–based binder degradation. Carbon corrosion, accelerated under high potential conditions, leads to structural collapse, loss of electrochemical surface area, and performance decline, while binder degradation compromises ionomer integrity, impacting proton conductivity and cell stability. In this work, a kinetic approach is employed to critically analyse the various degradation pathways, reaction rates, and key thermodynamic and kinetic parameters, providing a detailed and in-depth understanding of the degradation mechanisms under investigation. Additionally, this work systematically explores the key material and operational parameters influencing these degradation phenomena and assesses their degree of impact. Furthermore, it evaluates advanced characterisation techniques, including microscopy, spectroscopy, and electrochemical methods, to quantify degradation progression and identify failure modes. Mitigation strategies, such as the development of novel materials with enhanced properties and the optimisation of operational parameters, are also analysed. Finally, this review identifies gaps in the literature and outlines future research directions. By integrating recent findings, it contributes to advancing knowledge and driving future innovations towards more durable fuel cells.</p