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Silicon Photonic Devices Harnessing Ridge Resonance
No full textSilicon photonics has garnered increasing adoption as a platform for high-level integration of optical devices and electronic modules. The compatibility of silicon photonics with CMOS fabrication technology provides an avenue to scale up mass manufacture for commercialisation. In this context, recently, quantum-optical analogies have been gaining momentum as an excellent approach to realise different quantum phenomena in photonic platforms and harness their interesting behaviours for realisation of new photonic integrated devices. In particular, bound states in the continuum (BICs), refer to a special state with unconventional confinement, have attracted a great deal of attention thanks to their unique feature of having resonances of theoretically zero bandwidth. Our team at RMIT has recently introduced a BIC-based SOI ridge resonator which can produce a single, sharp resonance over a broad range of wavelengths with a high extinction ratio. However, these resonators require excitation from broad beams of laterally unguided slab modes, resulting in a large device footprint, which is not suitable for photonic integrated circuits. In addition, they lack a dedicated ‘drop' port while this feature is desirable in wavelength-division-multiplexing (WDM) systems. The aim of this thesis is to explore solutions to the problems faced by the BIC-based ridge resonator. This study is expected to make the ridge resonance concept a more attractive design choice and opening up opportunities to harness this type of resonance in photonic integrated devices and circuits. The thesis shows that the overall size of a ridge resonator can be significantly reduced by two orders of magnitude by adopting the closed-slab configuration instead of open slab, and replacing broad beams of laterally unguided slab modes with guided mode coupling from single-mode waveguides. The thesis also addresses the issue of lacking access to ‘drop' port by leveraging the concept of coherent tunneling by adiabatic passage (CTAP) - which was originally proposed in quantum mechanics. With this approach, the power of both ‘through' port and ‘drop' port can be simultaneously accessed. Finally, an investigation into high-order filters based on coupled ridge resonators is performed. It is shown that a high-order filter can be synthesised on an open slab with excitation from a top single-mode waveguide. Multiple ridge waveguides can be placed close to each other on the same slab, allowing a compact design. In summary, the BIC-based ridge resonance behaviour can be harnessed to achieve compact optical filters on the SOI platform with systematic design approaches. The investigation in this thesis is expected to lay the groundwork for further development and optimisation of ridge resonator configurations based on guided mode coupling.</p
Accelerating Materials Discovery For Gas Capture And Separation Applications Combining High Throughput Simulation And Machine Learning
No full textMachine learning (ML) methods have become increasingly popular across various domains. Particularly, scientific research appears to be adopting this technology rapidly. While topics such as medical sciences and climate change garner attention when ML is applied, its use in material science cannot be overlooked. Metal-organic frameworks (MOFs) stand out in this field as their reticular nature makes them suitable candidates for applying ML methods. This thesis focuses on using ML methods on MOFs for gas adsorption and separation purposes.
Background is provided on adsorption mechanics and the broader porous materials domain in the introduction section. The state of the art is explored in the literature review and the methods through which ML is applied in this project is discussed in the methodology section. ML was first applied to study the O2/N2 selectivity properties of MOFs in Chapter 4 of the thesis. The model’s predictions displayed good agreement with the values obtained through simulations; design strategies were derived through trends in the data.
The application of ML on predicting CO2 adsorption was then studied. As low partial-pressure conditions were considered, electrostatic interactions were the dominant force leading to adsorption. The commonly used descriptors did not capture information related to electrostatic interactions; to improve the models, descriptors that quantify the effects of framework charges were introduced. These were shown to improve the model and were orders of magnitude faster to obtain than other descriptors in the dataset. Finally, a classification model was successfully built to predict ammonia working capacity in temperature-swing conditions. This chapter also revised the charge-based descriptors from the previous chapter to make it more robust.</p
There's a traffic jam in brain!
No full textMemories, the greatest gift to mankind, shape who we are. Now imagine losing them—this is the what happens in Alzheimer’s disease, the leading cause of dementia, affecting millions globally without any effective treatment. In Australia alone, over a million people are projected to be affected by 2058. This is where my research comes into play. We are developing a new drug similar in action to a constituent found in green tea (epigallocatechingallate) that targets what we call as amyloid fibrils—sticky clumps that clog brain cells. Think of them like a never-ending traffic jam on a late evening drive towards home. Our drug clears this up, helping brain cells communicate again where a healthy brain can now store and form all the memories efficiently. Cherishing memories—that’s what our drug is here for.</p
Hybrid nanozymes with synergetic catalytic activity as antimicrobial agents
No full textAntimicrobial resistance (AMR) is an escalating global health crisis, with projections indicating it could cause up to 39 million deaths over the next 25 years, equivalent to more than three deaths every minute. My research focuses on the development of hybrid nanozymes, which are nanoparticles engineered to mimic natural enzymes and generate reactive oxygen molecules capable of destroying bacteria, including drug-resistant strains. By integrating metals and metal oxides, these hybrid nanozymes leverage a synergistic effect to amplify their catalytic and antimicrobial activity. This approach offers a promising, and cost-effective alternative to traditional antibiotics in the ongoing fight against resistant pathogens.</p
Liveability scorecard for LGA of Canterbury-Bankstown 2021: Understanding liveability inequities across the suburbs of Canterbury-Bankstown
No full textThis Local Government Area (LGA) Liveability Scorecard has been prepared by the Australian Urban Observatory in partnership with the Health Promotion Unit of the Sydney Local Health District. It has been designed to understand the liveability of individual suburbs within an LGA that can be used to prioritise future actions and investments of interest to councils, community, urban planners, developers, and other decision makers to achieve healthier and more liveable places across an entire LGA.</p
Analyzing Ride-Hailing Services Utilization in Greater Melbourne: Influences of Service Area and Vehicle Capacity
No full textRecent technological advancements have boosted ride-hailing services (RHS) to the forefront of urban transportation options, offering the potential to decrease private vehicle ownership by serving a larger population with fewer vehicles. However, their performance and service quality depend on the designated service areas and vehicle capacity limits. This study utilizes the agent-based model MATSim to analyze how service area and vehicle capacity variations affect RHS effectiveness in Greater Melbourne. Results from extensive simulations indicate that expanding service areas and increasing vehicle capacities significantly improve RHS accessibility and operational efficiency. This expansion leads to fewer vehicles on the road and reduced environmental impacts, with broader service areas serving more users and larger vehicle capacities decreasing per-trip travel distance. The study underscores the significance of integrating RHS within existing mobility systems and recommends zoning and fleet management policies for RHS as crucial tools for developing sustainable urban mobility.</p
The Immune Response of Ranched Southern Bluefin Tuna Infected With Aporocotylid Blood Flukes
No full textAporocotylids, also known as fish blood flukes, are a significant health concern for the Australian Southern bluefin tuna (SBT) aquaculture industry. Cardicola forsteri and C. orientalis are the two species that parasitise SBT during ranching. Mortalities of SBT have been associated with severe Cardicola spp. infections. Cardicola spp. infect the circulatory system of SBT with the adult fluke infecting SBT hearts (C. forsteri) or gills (C. orientalis) and the eggs of both species infecting the gills. Most health concerns associated with these infections are related to Cardicola spp. eggs. The SBT industry manages infections with the anthelminthic praziquantel (PZQ). However, despite the economic importance of SBT, little is known about how the SBT immune system responds to Cardicola spp. as infection develops. This thesis focused on improving the understanding of the SBT immune response to Cardicola spp. throughout the duration of SBT ranching by addressing 3 aims.
The first aim was to identify the relationship between SBT immune gene expression and the infection severity of adult or egg Cardicola spp. during standard commercial ranching. A targeted approach was used to quantify the expression of 6 immune genes (il1b, il8, igm, mhc2, tcrb and tnf2) at three ranching time points using reverse transcription quantitative polymerase chain reaction (RT-qPCR). The expression of the immune genes was measured from the SBT anterior kidney to represent a systemic immune response, and from SBT gills to represent a localised immune response. Cardicola spp. infection severity was measured using three techniques. Adult flukes were collected and counted from SBT hearts, Cardicola spp. eggs were counted under a microscope from gill whole mounts and C. forsteri and C. orientalis specific rDNA (ITS-2) was quantified from SBT gills using qPCR. Gene expression was correlated to the diagnostic results and showed differences in correlations between the Cardicola spp. life stages and species diagnostics. Expression of igm, mhc2 and tcrb were correlated to the number of adult flukes; il8 and igm correlated to the number of eggs; and tcrb was negatively correlated to the quantity of C. orientalis rDNA (ITS-2) in SBT gills. Inflammatory cytokines (il1b and il8) expression decreased in the gills with ranching time and genes that represent an adaptive immune response (igm, mhc2 and tcrb) expression increased over time in the kidney.
The second aim was to compare the gill and anterior kidney transcriptomes of C. forsteri infected SBT to uninfected SBT. The second aim expands on the first by using a total transcriptomic approach to understanding how all SBT genes are expressed during C. forsteri infection. SBT were collected during the commercial harvest from a single company. Cardicola spp. infection was diagnosed by the presence of adult flukes in SBT hearts and C. forsteri and C. orientalis rDNA (ITS-2) in SBT gills. The individuals that were positive for adult flukes and only C. forsteri rDNA (ITS-2) were considered as C. forsteri positive. RNA was extracted from the gill and anterior kidney of SBT, the mRNA was sequenced and aligned to the SBT genome. A count of the expressed genes was produced and normalised to 4 reference genes. Differentially expressed genes (DEGs) between C. forsteri positive and negative SBT for each organ were calculated with EdgeR and were considered significant when the p value adjusted for the false discovery rate was < 0.1. Immune system related transcripts in the gills of C. frosteri positive SBT showed an upregulation of the Notch signalling pathway. The immune system DEGs from the kidney showed C. forsteri positive SBT had a downregulation of the ubiquitin mediated proteolysis and 4 innate immune signalling pathways: NOD-like, C-type lectin, toll-like, and the RIG-I-like signalling receptor pathways. This was the first known study to document the transcriptome changes of SBT responding to a pathogen.
The final aim was to investigate the relationship between infection severity and C. forsteri specific antibodies over an extended ranching period. The third aim expands on aim 1 and 2 by understanding the long-term immune response. To address this aim SBT were collected from a single commercial company that ranched SBT for 45 weeks, which is longer than industry standard of 12-26 weeks. SBT IgM was purified from serum and an anti-SBT IgM antibody was produced so C. forsteri specific antibodies could be measured through an enzyme linked immunosorbent assay (ELISA). Cardicola spp. infection severity was measured by the number of adult flukes in the heart and C. forsteri and C. orientalis rDNA (ITS-2) in SBT gills. At all time points studied, SBT had greater levels of C. forsteri specific antibodies than negative controls while Cardicola spp. infection intensity remained low after an infection peak. C. forsteri antibody levels were positively correlated to C. forsteri rDNA (ITS-2) in SBT gills at two time points and were negatively correlated to the number of adult flukes at the peak infection intensity. There is a time delay between infection and specific antibody production, identified as a 4-5 week delayed positive correlation between the initial C. forsteri infection and the C. forsteri specific antibodies in this study.
This thesis contributes to understanding how the SBT immune system responds as Cardicola spp. infection develops within the ranching environment. The research has identified parallels to immune response dynamics seen in humans during schistosomiasis (disease caused by the human infecting blood fluke Schistosoma spp.). Immune response studies are important to understand how Cardicola spp. affects SBT which can help with improving health management for aquaculture industries troubled with aporocotylid infection.</p
New Test Open Educational Resource Record 20250507 KC
No full textThis is a new test record in the Open Educational Resources group. It is being used to test versioning functionality.</p
Typologies of community-informed adaptive reuse and wilding
No full textThis chapter delves into innovative collaborative design-research projects aimed at reimagining urban adaptation to climate and biodiversity challenges in Melbourne, Australia. By pioneering a novel typological approach across architecture, urban and landscape design, it envisions the integration of spontaneous ecologies and verdant spaces within urban landscapes. Three exemplar projects uniquely intertwine urban strategy—presented through dynamic exhibitions—and a typological methodology that adeptly responds to the diverse urban fabric. In a departure from conventional design processes, the approach begins by examining the inherent qualities and typologies of existing spaces, thereby unearthing transformative opportunities for the urban and built environment. This site-responsive method crafts potential urban reuse strategies, landscape types and habitats from spatial opportunities, guiding new urban and landscape strategies. Urban transformation is creatively driven by the characteristics of found spaces rather than traditional programmatic demands, embracing the 'building within the existing' concept articulated by Schittich. Through a comparative analysis of three applications, this typological framework demonstrates a strategic fusion of natural and built environments, fostering innovative urban ecologies. The study also revisits European 'Les Friches' and Asian wilding concepts (Saladdressing), adapting them to Melbourne's distinctive postcolonial, post-industrial context. This exploration necessitates a fresh perspective on 'wilding,' tailored to the region's harsher climatic realities and cultural landscape, thus paving the way for a reimagined urban future.</p
Integrated assessment of existing practices and development of pathways for the effective integration of nature-based water treatment in urban areas
No full textWater pollution poses a significant and escalating threat to urban environments, particularly in the rapidly expanding cities of Asia. Addressing this challenge requires implementing cost-effective solutions, and one such approach is the deployment of Nature-based Solutions (NbS) to treat septic tank effluents, canals and lakes. This study represents a pivotal step in this direction by formulating a comprehensive framework to assess the effectiveness and impacts of NbS. The research draws on six case studies spanning the Philippines, Sri Lanka and Vietnam, offering valuable insights into the practical application of NbS in diverse urban contexts. Furthermore, the study has yielded practical guidelines for the construction and installation of three key NbS components: Constructed Wetlands
(CWs), Constructed Floating Wetlands (CFWs), and Green Roofs (GRs). These guidelines were implemented through trial implementations, enhancing our understanding of their real-world performance. Moreover, stakeholder engagement played a vital role in this endeavour, as such gatherings provided essential data on public acceptance and the influence of policies and governance structures. The knowledge and insights from these interactions contribute significantly to the collective understanding of effectively
replicating and implementing NbS for water treatment in urban environments. The project successfully trained 72 early career professionals and students from project partners and stakeholders. It produced 23 publications, including a book, book chapters, journal articles, perspectives, resource materials reports and four short videos on NbS. These outcomes were achieved through the collaborative efforts of project partners and stakeholders, engaging in 29 events such as quarterly, national and regional meetings, field trips, focus group discussions, socio-economic surveys and extensive field trials.</p