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Experimental and numerical investigation on the dynamic response of RC ultra-high piers under multiple impacts
No full textIn recent years, bridges with ultra-high piers (UHPs, the pier height of which ≥ 100 m) have been increasingly used in mountainous areas and may be subjected to impact loads such as rock falls. However, research on the impact performance of UHPs is very limited, and it is essential to understand their dynamic responses and failure modes under impact loads. In this study, we conducted a rare large-scale experimental investigation on a 1/20-scale UHP specimen subjected to multiple impact tests via a pendulum impact system. The failure mode, impact force, and displacement of the UHP specimen were recorded and analysed. On this basis, the numerical model of UHP was established and validated against the experimental results using LS-DYNA. And systematic numerical analysis was subsequently conducted to investigate the influence of parameters on the impact response of a scaled entire bridge with UHPs, including impactor diameter, axial load, impact height, and impact velocity. The results indicated that UHP predominantly exhibited flexural failure modes under mid-height impact. The lower local and overall stiffness of UHPs results in smaller impact forces compared to similar tests on medium and low-height piers. The increase in impactor diameter from 0.25b to 1.5b (b: pier section width) increased the impact force by approximately 54 %; meanwhile, the increase in impact velocity from 5 to 20 m/s boosted the impact force by roughly 157 % and reduced the impact duration by about 76 %. In contrast, a higher impact height reduced the peak shear force at the pier bottom by 35.6–47.4 %. The findings can be used as references for the anti-impact design of UHPs
Enhanced Production of Five-Membered Ring Compounds Using a Biochar-Loaded Fe Catalyst: Catalytic Upgrading of Light Bio-Oil
No full textThe catalytic upgrading of light bio-oil (LB) is essential for enhancing the overall utilization of crude bio-oil. This study presents the synthesis of a biochar-loaded Fe catalyst (Fen-STC) via a simple one-step pyrolysis method and evaluates its performance in the upgrading of LB. The Fe species were primarily loaded onto the biochar carrier in the form of iron oxides (Fe3O4/Fe2O3), which further etched the biochar carrier, resulting in a substantial alteration of its structure and aromaticity. The optimized Fe1.0-STC exhibited a substantial increase in the specific surface area and a uniform distribution of iron oxides. Notably, this catalyst significantly enhanced the selectivity for producing five-membered ring compounds, such as cyclic ketones and furans, achieving a relative abundance of 70.23%, an increase of 87.74% compared to the control group. Further examination of hydroxyacetone and 1-hydroxy-2-butanone as model compounds elucidated the mechanisms underpinning catalytic upgrading, revealing a synergistic effect that facilitated the transformation of linear short-chain ketones into high-value cyclic compounds through aldol condensation, dehydration, and cyclization reactions. These findings suggest that the Fen-STC catalyst is a promising candidate for enhancing the quality of LB
Data-driven insights into protonic-ceramic fuel cell and electrolysis performance
No full textCell reproducibility remains a significant challenge for emerging proton-conducting ceramic electrochemical fuel cell and electrolyzer technologies. This study investigates the factors contributing to cell-to-cell performance variation. Gaussian process and random forest regressor machine learning models were utilized to analyze 86 cells for fuel cell performance and 84 cells for electrolysis performance. The study focused on BaCe0.4Zr0.4Y0.1Yb0.1O3−δ (BCZYYb4411) + NiO—BCZYYb4411—BaCo0.4Fe0.4Zr0.1Y0.1O3−δ (BCFZY) material sets for the negatrode, electrolyte, and positrode, respectively. Key processing and morphological parameters impacting performance were identified. The electrolyte thickness to grain size ratio emerged as a critical factor for both fuel cell and electrolysis performance, with maximum gains at ratios ≤1. A NiO particle size threshold of ∼6 μm was identified, below which performance increases markedly. Evaporating organics from the electrolyte spray or positrode application process before sintering may improve performance significantly, but the extent of this improvement remains uncertain. The optimal BCFZY positrode thickness for fuel cell performance is 20-25 μm. Fuel cell performance is primarily influenced by positrode microstructure. Optimizing this microstructure can bring the largest benefit to fuel-cell performance through reduced polarization resistances. In contrast, electrolysis performance is strongly governed by electrolyte microstructure. Improving electrolyte conductivity and reducing ohmic resistance greatly benefits electrolysis performance
Impact of acoustic index parameters on soundscape comparisons
Get PDFUnprecedented ecosystem changes have prompted prioritisation of scalable and informative environmental monitoring. Ecoacoustics derives information from passive acoustic monitoring of soundscapes as a proxy to describe ecological processes. Ecoacoustic indices are often used to characterise specific aspects of the acoustic environment, for example the Acoustic Diversity Index potentially reflecting local biophony. Increasing application of these indices raises concerns about the ecological relationship between the soundscape and the index values. The need to quantify their variance against validated ecosystem traits is becoming more appreciated. For several commonly used indices, the impacts of the parameter settings and sampling regimes on output values have not been fully explored, despite the potential to bias results. To address this, we conducted three sensitivity analyses on acoustic index parameters. The first explores raw output from the Acoustic Complexity Index at various parameter settings, on a single recording. The second models the output of four common indices (Bioacoustics Index and Acoustic Complexity, Diversity and Evenness Indexes) using Bayesian mixed effects models on two datasets and explores how comparative differences change with parameter settings. The third explores the effect of the pitch of simulated animal calls on the output of the four indices. The analyses demonstrate that parameter selection alone can influence the magnitude and direction of difference between acoustic index outputs, in turn affecting comparative interpretation. These effects are also dependent on the soundscape data (e.g. sampling frequency, target frequency bands). We provide insights into drivers of these effects and recommendations to better understand the implications of index variance for within- and between-study comparisons. Recommendations include identifying frequency bands relevant to the research question, selecting parameters appropriately and using sensitivity analyses to determine if parameter selection is influencing interpretation of results. Further work is required to ecologically validate acoustic indices and their relationships to soundscapes. Standardised methods are needed to identify the scale to which differences in the ecosystem can be resolved and compared
Phenolic, antioxidant capacity, and antinutritional compounds in different Australian Acacia seeds
Get PDFThe polyphenols, antioxidant activities, and antinutrients in Acacia seeds of different species, growing locations, and harvest years were characterised in this study. The main phenolic compounds were 6-hydroxy-2-methylindole and 2,2-methylenebis(6-tert-butyl-methylphenol). The total phenolic and total flavonoid contents of the free polyphenol fractions were positively correlated, while the total phenolic content and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), 2,2-diphenyl-1-picrylhydrazyl, and oxygen radical absorbance capacity of the bound fractions were negatively correlated. There were no differences in trypsin and chymotrypsin inhibition activities across all seed batches. The lowest phytate (11.1038 ± 0.006 mg/g) and tannin contents (2.0323 ± 0.7462%) were found in Acacia retinodes Amphitheatre 2020 and A. retinodes Firgrove 2022, respectively. The highest saponin (45.4578 ± 12.2990%) and oxalate contents (4.2396 ± 0.7949%) were found in A. retinodes Grampians 2020 and A. retinodes Firgrove 2020, respectively. The results of this study showed differences in antioxidant activities and antinutrients content which implies that compositional values should not be extrapolated between different species and harvest years
Protocol for a wait list randomised controlled trial: Using social media for health promotion, communication and advocacy – A massive open online course
Get PDFIntroduction
Social media can be a powerful tool for raising awareness, engaging and mobilising communities, collecting data, fostering behaviour change and advancing advocacy efforts. However, many public health professionals hesitate to incorporate social media into their work. In responding to this need, we developed a 6-module massive open online course (MOOC) designed to improve knowledge and understanding of how to effectively frame health promotion messages and increase confidence in using social media for health promotion, communication and advocacy. This paper outlines the protocol for a mixed-methods evaluation of this MOOC.
Methods
A wait list randomised controlled trial, guided by elements of the RE-AIM and Kirkpatrick models, will collect qualitative and quantitative data from eligible participants at three time points: baseline (T0), interim post-test (T1) and final post-test (T2). The primary outcome measure will be participants' social media context awareness. Secondary outcomes will be social media competency and the impact of the MOOC on professional practice. Additionally, a process evaluation will examine implementation, participant engagement and satisfaction with the MOOC.
Conclusion
This research will assess the effectiveness of a MOOC in enhancing health promotion knowledge, framing health messages, and confidence in using social media for health promotion, communication and advocacy among public health professionals. The findings will inform the design and evaluation of future online programs in this field, with results disseminated upon completion of the study.
Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12624001486516
Autistic Traits & Emotion Functioning: An Examination of Emotion Regulation and Alexithymia
Get PDFThe present thesis aims to examine the nature of the relationship between autistic traits and emotion functional difficulties, covering both negative and positive emotions. This thesis composed of two studies with study (1) focusing on emotion regulation ability (N = 661) and study (2) on alexithymia (N = 868). Each study found that difficulties regulating both negative and positive emotions should be considered when examining autistic traits, which holds implications for research and clinical settings
A model for a social justice hub for social work education
No full textSocial justice is a foundational principle in global social work, underpinning its professional identity. Amidst global challenges rooted in neoliberal capitalism and colonial legacies, social work’s commitment to justice is vital. While social work students typically learn about social (in)justice theories, developing advanced skills in social justice practice requires an integrated and experiential curriculum, such as field education. The Social Justice Hub at Curtin University serves as a conduit for engagement with university resources, aiming to drive transformative change towards a more just society. Social work students on field placement codesigned the Social Justice Hub to create projects and innovations that are collaborative responses to enduring social justice problems. The placement model addresses a gap in learning about community building, project management and co-designing projects for social justice outcomes. This paper describes the Social Justice Hub and its development as a field placement opportunity for learning about social justice practice
The Soviet and Russian navies: From the Cold War to the Cold War 2.0, 1945-2024
No full textThis chapter examines the rise of the Soviet navy to a truly 'ocean-going' force during the Cold War, its subsequent post-Soviet fall as a Russian force and the more recent rekindling of Russian naval power under Vladimir Putin. At the end of the Great Patriotic War, the Soviet Union was not a major naval power, possessing a navy focussed on coastal defence and support of troops on land. Ambitions for a truly 'ocean-going' fleet would not be realised until the 1970s following a period of dramatic growth in Soviet naval power from the mid-1960s onwards. Drivers for this force included the need to combat US nuclear weapons at a distance from the Soviet coastline and the need to deploy and protect the naval leg of the Soviet Union's own strategic nuclear forces. The collapse of the Soviet Union meant a steep decline in post-Soviet Russian naval power, although there has been some attempt to resurrect Russian naval capabilities and reach under the government of Vladimir Putin
