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Self-powered, thermally stable Sb2Se3-based high-performance broadband photodetector
No full textHigh-performance broadband photodetectors are widely studied due to their unique significance in military and industrial applications. Vander Waals materials-based detector that simultaneously achieves a fast and high response are prerequisites for expanding the current capabilities of the optoelectronic device. Yet the thermal stability of the Vander Waals materials-based broadband (450 nm to 1250 nm) device is rarely addressed. Here, an antimony selenide (Sb2Se3) based photodetector is reported, which reveals high photo-responsivity and detectivity up to 924 mAW−1 (346 mAW−1) and 2.7 × 1010 Jones (1.0 × 1010 Jones) for the illumination wavelength 1064 nm (532 nm) under photovoltaic mode. Moreover, under 0 V-applied bias condition, the developed detector thermal stability was tested, and up to 100 °C devices disclosed a stable behavior. Further, the fabricated Sb2Se3-based broadband device was also tested under photoconductive mode. The photodetector demonstrates high responsivities of 1.5 × 104 mAW−1 (1.3 × 104 mAW−1) and 4.1 × 104 mAW−1 (3.8 × 104 mAW−1) for the illumination wavelength 532 nm and 1064 nm, respectively at room temperature (100 °C) under 0.5 V applied bias condition and 1 µW optical power. The design device can offer ideas for constructing high thermal stability and encouraging such materials in broadband photodetector applications. The state-of-the-art Sb2Se3-based detector can facilitate the translation of solution-processed optoelectronic applications from the laboratory to the marketplace
Cell interactions with lipid nanoparticles possessing different internal nanostructures: Liposomes, bicontinuous cubosomes, hexosomes, and discontinuous micellar cubosomes
No full textHypothesis: Lyotropic liquid crystalline nanoparticles (LLCNPs) with complex internal nanostructures hold promise for drug delivery. Cubosomes, in particular, have garnered interest for their ability to fuse with cell membranes, potentially bypassing endosomal escape challenges and improving cellular uptake. The mesostructure of nanoparticles plays a crucial role in cellular interactions and uptake. Therefore, we hypothesise that the specific internal mesophase of the LLCNPs will affect their cellular interactions and uptake efficiencies, with cubosomes exhibiting superior cellular uptake compared to other LLCNPs. Experiments: LLCNPs with various mesophases, including liposomes, cubosomes, hexosomes, and micellar cubosomes, were formulated and characterised. Their physicochemical properties and cytotoxicity were assessed. Chinese Hamster Ovarian (CHO) cells were treated with fluorescently labelled LLCNPs, and their interactions were monitored and quantified through confocal microscopy and flow cytometry. Findings: The non-lamellar LLCNPs showed significantly higher cellular interactions compared to liposomes, with cubosomes exhibiting the highest level. However, there was no significant difference in relative cell uptake between cubosomes, hexosomes, and micellar cubosomes. Cell uptake experiments at 4 °C revealed the presence of an energy-independent uptake mechanism. This study provides the first comparative analysis of cellular interactions and uptake efficiencies among LLCNPs with varying mesophases, while maintaining similar size, composition, and surface charge
Amorphous Ni(OH)2-Ni3S2/NF nano-flower heterostructure catalyst promotes efficient urea assisted overall water splitting
No full textUrea assisted overall water splitting represents a cost-effective and efficient technology for hydrogen production, which not only obviates the generation of explosive H2 and O2 gas mixture but also minimizes the energy cost for the water splitting. In this study, we employed a one-pot hydrothermal method to directly synthesize Ni(OH)2-Ni3S2/NF hybrid nanoflowers on a nickel foam (NF) substrate, resulting in efficient and stable bi-functional electrocatalysts for urea oxidation reaction (UOR) and hydrogen evolution reaction (HER). Under alkaline conditions, the Ni(OH)2-Ni3S2/NF catalyst exhibits low voltage requirements of 1.346 V and −0.014 V vs. RHE with a current density of 10 mA cm−2 for UOR and HER, respectively. Furthermore, when employing the Ni(OH)2-Ni3S2/NF catalyst as both anode and cathode for urea-assisted overall water splitting, it requires a cell voltage of merely 1.396 V with a current density of 10 mA cm−2, which is notably lower than the voltage required for complete water decomposition at the same current density (1.568 V vs. RHE). The one-step synthesis of the Ni(OH)2-Ni3S2/NF catalyst lays a foundation for further exploration of other transition metal complexes as dual-function electrocatalysts, enabling energy-efficient electrolytic hydrogen production and the treatment of urea-rich wastewater
Phase Noise Analysis of Time Transfer over White Rabbit-Network Based Optical Fibre Links
No full textWhite Rabbit (WR) is an optical fibre-based time-frequency synchronization technology typically used in timekeeping laboratories for distributing time-frequency signals from a reference clock to distant locations. The accuracy of the received signals at the user end can be affected by random noise processes present in the WR network due to the internal electronic components of WR devices. In this paper, we investigate the presence of random noise processes in the WR network. We then study their statistical properties and model the distribution based on experimentally recorded measurements. According to our study, the probability density function (PDF) follows a Gaussian mixture model (GMM) with varying distribution parameters, and the correlation analysis indicates a strong correlation of the phase noise process over the temporal samples. Furthermore, the developed phase noise models have also been verified by comparing them against additional experimental data. Finally, we present the methodology to generate the phase noise process using computer simulations with the PDF and correlation models developed in this work to help algorithm developers and equipment manufacturers make use of our results
The Colony Cares for Everyone
No full textThis doctoral project is by creative practice and exegesis. The culmination of the research is a site-specific installation of photography, video and sound titled The colony cares for everyone. This body of work was created where I grew up as a settler on the unceded Lands of the Larrakia and Wulna people in the Northern Territory (NT). It seeks to deconstruct and reimagine settler narratives of ‘development’ in the NT, with a particular focus on settler extractivism including the recent growth of lithium mining on Larrakia Land, Cox Peninsula.
The exegesis begins with the question: how can experimental material processes grounded in Land be developed into artworks that challenge ongoing settler extractivist narratives? Methodologically the research draws on local, Indigenous knowledge, from the NT and First Nations globally, alongside seemingly disparate but deeply connected aspects of political and artistic worlds to inform the artwork developments. Working with a Termite colony beneath my childhood home, I embarked on a series of experiments to establish material processes to locate and consider historical narratives that enable settler claims to Land, while linking these to present-day proposals to ‘develop the north’. These processes culminated in feeding the Termites books I categorise as ‘settler fanfiction’ which I then interpreted through lens-based practices.
The exegesis presents an exposition of the final installation held in a repurposed University boardroom, operationalising the research in a new context and expanding the frame of the images I’ve produced to provoke broader reflections on settler extractivism. The outcomes contribute to a reimagining of settler narratives of progress in the NT and beyond through the metaphorical possibilities of transformation involving more-than-human logics.</p
Growth Areas Liveability Scorecard for Perth
No full textThis report is the first series of Growth Areas Liveability Scorecard Reports developed in partnership with the National Growth Areas
Alliance. The Growth Area Liveability Scorecards have been
developed for the capital cities of Adelaide, Brisbane, Melbourne,
Sydney and Perth include indicators and maps from the
Australian Urban Observatory measuring the liveability of 21
Australian cities. The Scorecards focus on the fastest growing
Local Government Areas located in outer metropolitan and
peri-urban regions of Australia’s five largest capital cities. The
Growth Area Liveability Scorecards identify differences between
Growth Areas and Non-Growth Areas across Australian capital
cities. Results are based on previous City Liveability Scorecards
developed by the Australian Urban Observatory @ RMIT University
and are based on 2021 indicator results.
More detailed neighbourhood, suburb, and Local Government
Area results across Australian cities are available online at
auo.org.au.</p
Submission into the Inquiry into Climate Resilience, 28 June 2024 - Submission No 222 - RMIT University Urban Futures Enabling Impact Platform
No full textThis submission draws together the collective experience and knowledge of a diverse set of RMIT specialists from across the university’s built environment disciplines. We are urban planners, geographers, engineers, architects, landscape architects and building scientists, and this submission was coordinated by our Urban Futures Enabling Impact Platform. Accordingly, our focus is broad, but primarily urban. We welcome the opportunity to provide a submission to the Inquiry into Climate Resilience.</p
Tensile strength modelling of glass fiber-polymer composites in fire
No full textA thermal-mechanical model is presented to calculate the tensile strength and time-to-failure of glass fiber reinforced polymer composites in fire. The model considers the main thermal processes and softening (mechanical) processes of fiberglass composites in fire that ensure an accurate calculation of tensile strength and failure time. The thermal component of the model considers the effects of heat conduction, matrix decomposition and volatile out-gassing on the temperature-time response of composites. The mechanical component of the model considers the tensile softening of the polymer matrix and glass fibers in fire, with softening of the fibers analyzed as a function of temperature and heating time. The model can calculate the tensile strength of a hot, decomposing composite exposed to fire up to the onset of flaming combustion. The thermal-mechanical model is confined to hot, smoldering fiberglass composites prior to ignition. Experimental fire tests are performed on dry fiberglass fabric and fiberglass/vinyl ester composite specimens to validate the model. It is shown that the model gives an approximate estimate of the tensile strength and time-to-failure of the materials when exposed to one-sided heating at a constant heat flux. It is envisaged the model can be used to calculate the tensile softening and time-to-failure of glass-polymer composite structures exposed to fire.</p
Gold nanoparticle adsorption alters the cell stiffness and cell wall bio-chemical landscape of Candida albicans fungal cells
No full textHypothesis: Nanomaterials have been extensively investigated for a wide range of biomedical applications, including as antimicrobial agents, drug delivery vehicles, and diagnostic devices. The commonality between these biomedical applications is the necessity for the nanoparticle to interact with or pass through the cellular wall and membrane. Cell-nanomaterial interactions/uptake can occur in various ways, including adhering to the cell wall, forming aggregates on the surface, becoming absorbed within the cell wall itself, or transversing into the cell cytoplasm. These interactions are common to mammalian cells, bacteria, and yeast cells. This variety of interactions can cause changes to the integrity of the cell wall and the cell overall, but the precise mechanisms underpinning such interactions remain poorly understood. Here, we investigate the interaction between commonly investigated gold nanoparticles (AuNPs) and the cell wall/membrane of a model fungal cell to explore the general effects of interaction and uptake. Experiments: The interactions between 100 nm citrate-capped AuNPs and the cell wall of Candida albicans fungal cells were studied using a range of advanced microscopy techniques, including atomic force microscopy, confocal laser scanning microscopy, scanning electron microscopy, transmission electron microscopy, and synchrotron-FTIR micro-spectroscopy. Findings: In most cases, particles adhered on the cell surface, although instances of particles being up-taken into the cell cytoplasm and localised within the cell wall and membrane were also observed. There was a measurable increase in the stiffness of the fungal cell after AuNPs were introduced. Analysis of the synchrotron-FTIR data showed significant changes in spectral features associated with phospholipids and proteins after exposure to AuNPs
Massive transformations in titanium alloys: Role of relative orientation of adjacent parent grains
No full textMassive transformations occur in both additively and conventionally manufactured titanium (Ti) alloys. Unlike martensitic transformations, massive transformations can result in patch-like massive phases (αm) that traverse the parent prior-β grain boundaries (GBs). However, the conditions favouring the formation of these trans-GB αm-phases in Ti alloys remain largely unexplored. Through characterising the trans-GB αm-phases in α-β Ti alloys fabricated by additive and conventional processes, we find that their formation always occurs when two neighbouring prior-β grains share or nearly share a {110} pole, without exception. These trans-GB αm-phases exhibit concentrated {0001} poles while their {112¯0} poles spread widely. In addition, as metastable phases, they tend to decompose into ultrafine α-β lamellae. The role of relative orientation of adjacent parent grains in massive transformations and the implications for microstructural innovations in α-β Ti alloys are discussed