Swinburne University of Technology
  • Melbourne, Victoria, Australia
Recent publications
Epilepsy is a neurological disorder that affects the nervous system and is characterized by recurrent seizures. Experimental data shows that increase in the extracellular potassium concentration can support the generation of seizures and that the T-type calcium channel antagonists can be effective as anti-epileptic drugs. To investigate these two phenomena in detail, we combine microscopic level modelling using Hodgkin–Huxley formalism and a macroscopic level approach using a neural mass model. The microscopic level approach describes the initiation of action potentials in individual neurons using conductance-based model. The macroscopic (neural mass model) approach is a low-dimensional phenomenological model that describes the activity of a large population of neurons. The neural mass model replicated the interactions between inhibitory and excitatory neuronal populations by using a sigmoidal function that converts neuronal postsynaptic potential into the average spiking rate of a given population. This sigmoidal function links two levels of modelling: microscopic and macroscopic. Our results are in agreement with experimental data and show that an increase in the extracellular potassium concentration or an increase in the T-type calcium conductance can cause brain network transitions from normal background to pathological seizure-like dynamics. In addition, the results show that these transitions only happen for a limited range of network parameters and that the slow-inhibitory synaptic gain has a stronger effect on network dynamics during transitions than the fast-inhibitory synaptic gain.
This paper investigates the notion of the financial Kuznets curve in an emerging country—Jordan. Both variants of the financial Kuznets curve (growth financial Kuznets curve and inequality financial Kuznets curve) have been examined using different time series methodologies applying to a sample period from 1993 to 2017. The unobserved components model results provide evidence for both variants of the financial Kuznets curve when using private credit to GDP as a proxy for financial-sector development. Moreover, non-nested model tests suggest that financial intermediaries are relatively more important than stock markets for income inequality. Overall, this paper provides evidence for the financial Kuznets curve in emerging countries. Moreover, it provides new insights for policymakers in Jordan in their challenge to boost economic growth and decelerate income inequality, by reversing the trend towards the concentration of power in the financial sector and creating public-financial institutions that provide affordable credit to small businesses and households.
The rapid advance of mild aqueous zinc-ion batteries (ZIBs) is driving the development of the energy storage system market. But the thorny issues of Zn anodes, mainly including dendrite growth, hydrogen evolution, and corrosion, severely reduce the performance of ZIBs. To commercialize ZIBs, researchers must overcome formidable challenges. Research about mild aqueous ZIBs is still developing. Various technical and scientific obstacles to designing Zn anodes with high stripping efficiency and long cycling life have not been resolved. Moreover, the performance of Zn anodes is a complex scientific issue determined by various parameters, most of which are often ignored, failing to achieve the maximum performance of the cell. This review proposes a comprehensive overview of existing Zn anode issues and the corresponding strategies, frontiers, and development trends to deeply comprehend the essence and inner connection of degradation mechanism and performance. First, the formation mechanism of dendrite growth, hydrogen evolution, corrosion, and their influence on the anode are analyzed. Furthermore, various strategies for constructing stable Zn anodes are summarized and discussed in detail from multiple perspectives. These strategies are mainly divided into interface modification, structural anode, alloying anode, intercalation anode, liquid electrolyte, non-liquid electrolyte, separator design, and other strategies. Finally, research directions and prospects are put forward for Zn anodes. This contribution highlights the latest developments and provides new insights into the advanced Zn anode for future research.
In spite of recent moves to wean the world of fossil fuels, coal remains the main source of power in many countries. Coal yards are prone to spontaneous ignition, a problem faced in every country that stores or transports coal. Depending on the environment-temperature, ventilation, and the rank of the coal-heating and self-ignition can be a longer or shorter process, but the possibility can never be entirely dismissed. A plethora of studies have modelled this oxidation behavior and proposed countermeasures. Most often, human intervention is necessary, which is both slow and dangerous for the firefighters involved. In this study, we propose to build a complete firefighting solution which is mounted on a number of towers sufficient to cover the area of an open coal yard, complete with redundancy. Each tower includes an inexpensive infrared detector, a water dispenser and a controller programmed to identify areas of elevated temperature, and actuate the dispenser. The heat direction algorithm calculates the parameters to position the water dispenser so that it covers the area. A prototype has been built from inexpensive components to demonstrate the effectiveness at detecting and extinguishing arising fires, and a solution has been costed for the coal yard in the case study. This work has been conducted in collaboration with the managers of the coal yard of a power plant.
We review the application of discrete time crystals created in a Bose-Einstein condensate (BEC) of ultracold atoms bouncing resonantly on an oscillating atom mirror to the investigation of condensed matter phenomena in the time dimension. Such a bouncing BEC system can exhibit dramatic breaking of time-translation symmetry, allowing the creation of discrete time crystals having up to about 100 temporal lattice sites and suitable for hosting a broad range of temporal condensed matter phenomena. We first consider single-particle condensed matter phenomena in the time dimension which include Anderson localization due to temporal disorder, topological time crystals, and quasi-crystal structures in time. We then discuss many-body temporal condensed matter phenomena including Mott insulator phases in time, many-body localization in time, many-body topological time crystals and time crystals having long-range exotic interactions. We also discuss the construction of two (or three) dimensional time lattices, involving the bouncing of a BEC between two (or three) orthogonal oscillating mirrors and between two oscillating mirrors oriented at 45 ∘ . The latter configuration supports a versatile Möbius strip geometry which can host a variety of two-dimensional time lattices including a honeycomb time lattice and a Lieb square time lattice. Finally, we discuss the construction of a six-dimensional time-space lattice based on periodically driven BECs trapped in a three-dimensional optical lattice.
Removal of antimonite [Sb(III)] from the aquatic environment and reducing its biotoxicity is urgently needed to safeguard environmental and human health. Herein, crawfish shell-derived biochars (CSB), pyrolyzed at 350, 500, and 650 ° C, were used to remediate Sb(III) in aqueous solutions. The adsorption data best fitted to the pseudo-second-order kinetic and Langmuir isotherm models. Biochar produced at 350 ° C (CSB350) showed the highest adsorption capacity (27.7 mg g − 1 ), and the maximum 78% oxidative conversion of Sb(III) to Sb(V). The adsorption results complemented with infrared (FTIR), X-ray photoelectron (XPS), and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy analyses indicated that the adsorption of Sb(III) on CSB involved electrostatic interaction, surface complexation with oxygen-containing functional groups (C = O, O = C–O), π–π coordination with aromatic C = C and C–H groups, and H-bonding with –OH group. Density functional theory calculations verified that surface complexation was the most dominant adsorption mechanism, whilst π–π coordination and H-bonding played a secondary role. Furthermore, electron spin resonance (ESR) and mediated electrochemical reduction/oxidation (MER/MEO) analyses confirmed that Sb(III) oxidation at the biochar surface was governed by persistent free radicals (PFRs) (•O 2 ⁻ and •OH) and the electron donating/accepting capacity (EDC/EAC) of biochar. The abundance of preferable surface functional groups, high concentration of PFRs, and high EDC conferred CSB350 the property of an optimal adsorbent/oxidant for Sb(III) removal from water. The encouraging results of this study call for future trials to apply suitable biochar for removing Sb(III) from wastewater at pilot scale and optimize the process. Graphical abstract
A voltage gain interleaved soft switched DC-DC Boost converter without auxiliary switch is proposed in this paper. Step-up characteristics are achieved without using any transformer, coupled inductor, voltage multiplier cell, switched inductor/switched capacitor in the proposed topology. All semiconductor devices operate under soft-switching conditions. Consequently, the converter has high efficiency. The auxiliary circuit is not located in the main power path, and the control circuit remains PWM. All advantages of interleaved topologies are gathered in the proposed converter. The converter efficiency is equal to 97.6% at nominal power. All mentioned benefits candidate the converter to use in photovoltaic applications. A 200 W prototype of the converter is constructed and tested in the laboratory. The experimental results are in total agreement with the theoretical considerations. Crown
Microgrids are facing several operational and control issues while integrating with the grid. To deal with it, STATCOM, as one of the emerging power converter circuits, is connected with such microgrids. STATCOM with microgrid introduces current harmonic, inherent resonance, and active power losses related to high switching frequency. Filter design can help attenuate these effects and maintain the predefined standards as in IEEE 519-1992 and IEEE P1547.2-2003. There are also some more points of concern about filter design. Inappropriate filter types and parameters may cause worse filtering, reactive power surplus production, and low power factor. Therefore, this paper suggests that the reactive power compensation capability, as a local area problem, must be attended through the proper designing of LCL filtered grid-tied STATCOM. The parameters are estimated through transient analysis, power quality, and power balance studies for proposed Micro-grid and the results obtained are compared using nature-inspired algorithms such as GA, PSO, and FA over conventional mathematical formulation. The main contributions of this work are; (i) study of system with the inclusion of voltage and frequency-dependent load, (ii) modified STATCOM model clubbing reactive power control feedback and LCL filter with damping resistance, (iii) real and reactive power tracking system using dynamic compensator capabilities, and (iv) suppression of total harmonic distortions along with real and reactive power tracking using advanced tuning for filter parameters with GA, PSO, and FA based algorithms.
Cold-formed steel (CFS) self-drilling screw connections are popular in construction industry due to rapid fastening and ease of installation. However, the performance of the CFS connections is very critical when they are exposed to corrosive environments such as humid and acidic or chloride-rich environments. The corrosion damage of CFS structures when exposed to these environments can result in significant reduction of mechanical properties, which can affect the safety and durability of such structures. Very limited research is available in the literature to investigate the effect of corrosion on the behaviour of CFS connections. This issue is addressed herein through an experimental investigation. This paper presents a total of 36 new experiments on different types of CFS self-drilling screws (12 and 14 gauge) and steel sheet thickness (2.5 mm). Half of the tests were for corroded specimens and the remaining half were for non-corroded specimens. Further, one to two screws per arrangements connecting the steel sheets having yield strength of 450MPa, were tested. Screws were immersed for 31 days and the CFS plates were immersed for 8 weeks in corrosion chamber before the tests were conducted. The experimental program was designed to investigate the effect of number of screws on shear strength of corroded specimens. Furthermore, a nonlinear explicit dynamic FE model was developed and validated against the experimental test results. The FE results were in reasonable agreement with the test results, both in terms of connection strength and failure modes.
Depth cues are crucial to increase user perception and spatial awareness of the remote environment when remotely guiding complex robotic systems. A mixed reality (MR) integrated 3D/2D vision and motion mapping framework for immersive and intuitive telemanipulation of a complex mobile manipulator is presented. The proposed 3D immersive telerobotic schemes provide the users with depth perception through the merging of multiple 3D/2D views of the remote environment via MR subspace. The mobile manipulator platform consists of a 6°-of-freedom (DOF) industrial manipulator, 3D-printed parallel gripper, and mobile base, which can be controlled by non-skilled operators who are physically separated from the robot working space through a velocity-based imitative motion mapping approach. This work evaluates the impact of depth perception and immersion provided by integrated 3D/2D vision and motion mapping schemes on teleoperation efficiency and user experience in an MR environment. In particular, the MR enhanced systems maintain spatial awareness and perceptual salience of the remote scene in 3D, facilitating intuitive mixed reality human-robot interaction (MR-HRI). This study compared two MR-integrated 3D/2D vision and motion mapping schemes against a typical 2D Baseline visual display method through pick-and-place, assembly, and dexterous manufacturing tasks. The MR-integrated 3D/2D vision and motion mapping schemes of teleoperation reduced overall task completion times by 34% and 17%, compared to the MR-2D Baseline, while minimizing training effort and cognitive workload.
The empathy-autistic trait relationship is complex and controversial. Empathy research is often undermined by unidimensional approaches to defining and measuring a multidimensional construct. This study regresses autistic trait level variation onto cognitive and emotional empathy variables across modalities (self-report, behavioural, and physiological) using a non-clinical adult sample (N = 123). We also account for several important covariates (age, sex, IQ, years of education and visual attentional behaviour). Self-report (trait-based) cognitive and emotional subscales predicted AQ more strongly and frequently than lab-based measures (behavioural/physiological; state-based), in directions consistent with prior findings. Emotional empathy questionnaire subscales differed in predictive directionality; a finding discussed with reference to state-trait measurement divergences and problematic subscales such as the personal distress scale of the Interpersonal Reactivity Index, which may contribute inconsistency in emotional empathy findings. Visual (in)attention was a consistent covariate predictor of AQ, highlighting the importance of accounting for gaze in autism trait studies to avoid erroneous conclusions. Findings are discussed with reference to the challenge of bridging the gaps between lab, theory, and application. Results further support the broader autism phenotype notion and contribute to debate concerning the relationship between empathy and autistic traits.
Evidence regarding the impact of product line breadth (PLB) on brand performance remains fragmented; the current research proposes an influential effect of product equity in determining PLB success. To test these predictions, Study 1 first identifies heterogeneous effects of PLB on brand performance according to the levels of product equity. Specifically, PLB hinders (improves) the performance of low (high) product equity brands. Then Study 2 identifies two drivers of PLB effectiveness, product attribute differences and competitive intensity, that have contrasting influences for brands with high versus low product equity. These influences exert long-term, cumulative effects (i.e., over 104 weeks). To ensure the generalizability and applicability of the findings, this research effort spans a vast consumer scanner data set, involving 268 brand panels, 14 product categories, and three retailers. Based on this collected evidence, the authors propose a matrix of managerial actions that practitioners can adopt to increase their PLB effectiveness.
Against the uncertainty caused by the information overload in the online world, consumers can benefit greatly by reading online product reviews before making their online purchases. However, some of the reviews are written deceptively to manipulate purchasing decisions. The purpose of present study is to determine which feature combination is most effective in fake review detection among the features of sentiment scores, topic distributions, cluster distributions and bag of words. In this study, additional feature combinations to a sentiment analysis are searched to examine the critical problem of fake reviews made to influence the decision-making process using review from amazon.com dataset. Results of the study points that behavior-related features play an important role in fake review classifications when jointly used with text-related features. Verified purchase is the only behavior related feature used comparatively with other text-related features.
This paper thoroughly discusses the design features and operating procedures of six popular conventional MPPT methods. Accordingly, the corresponding modifications of the conventional MPPT methods are analyzed and reviewed. A comprehensive comparative analysis of the twenty-eight adaptive MPPT algorithms is performed based on the tracking time, steady-state oscillations, conversion efficiency, algorithm complexity, implementation cost, capability to perform on the partial shading conditions, etc. The performances of the selected methods are illustrated on the radar graph diagram. The radar graph diagram's contour area helped select the best-performing methods. The summary of this paper will demonstrate a straightforward approach to the readers to select the suitable MPPT methods.
In this paper, high-velocity impact resistance of lightweight laminates with multi-layers of carbon-fibre/epoxy laminates sandwiched by two titanium alloy skins and aluminium alloy skins was extensively investigated by experiments with a total of 48 impact tests conducted. The ballistic limit of the titanium-based carbon-fibre/epoxy laminate was estimated to be between 241.6 m/s and 257.1 m/s. Impact velocity governed energy absorption and the corresponding damage modes were characterised and identified. The influence of fibre metal laminates configuration on the impact resistance was then experimentally investigated at a fixed impact velocity with full penetration in ten types of laminates. The results also showed that thicker skin and higher number of fibre layers favoured the specific energy absorption in the tested matrix.
Lithium-ion batteries (LIBs) need to be heated before use at low temperatures to avoid poor electric vehicle performance. In this study, a self-heating method for LIBs at low temperatures is proposed, where the influence of various heating parameters on heating performance is explored experimentally. To make the balance between heating speed and capacity degradation while achieving efficient preheating, a lumped parameter thermal model and an empirical capacity fade model are established to determine appropriate duty ratio and external resistance, which can predict the corresponding time required for LIBs to be heated to the target temperature and reveal the capacity loss of LIBs quantitatively after repeated heating. A multi-objective optimization method based on non-dominated sorting genetic algorithm II (NSGA-II) is employed to obtain the Pareto optimal front between heating speed and capacity degradation, which leads to the selection of the optimal electrical parameters with the help of K-means clustering algorithm and three newly defined heating performance indicators. Finally, the duty ratio and external resistance are preferably 80% and 203.98 mΩ through the NSGA-II method, respectively. The experimental results verify the optimal heating strategy which can heat the LIB quickly from – 20.56 °C to 0 °C within 70 s. This optimal heating strategy is applied to heat the LIB for 200 times, the battery capacity degradation is only about 7.72%.
Cholera is an acute intestinal infectious disease caused by the bacterium Vibriocholerae. To explore the multiple effects of spatial mobility, spatial heterogeneity and the seasonality on the transmission of cholera, we propose a time periodic reaction–diffusion equation model with latent period. Based on the basic reproduction number R0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathscr {R}_0$$\end{document}, we establish a threshold-type result. And in the case where all the parameters are constants and R0>1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathscr {R}_0>1$$\end{document}, we show the global attractivity of the endemic steady state by constructing Lyapunov functionals. Finally, we perform some numerical simulations. Our simulations show that (i) increasing the vaccination rate of susceptible individuals and vaccine protective efficacy can reduce the transmission risk R0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathscr {R}_0$$\end{document}; (ii) decreasing the transmission coefficient of contact with infected individuals, the transmission coefficient of contact with hyperinfectious vibrios and the transmission coefficient of contact with hypoinfectious vibrios can reduce the transmission risk R0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathscr {R}_0$$\end{document}; (iii) it is possible to underestimate the transmission risk R0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathscr {R}_0$$\end{document} in the periodic system if the spatial averaged system is used, based on some experimental data.
Many of the existing tension stress-strain relations for concrete used in smeared shear models consider the contribution of concrete in tension even after steel yielding. Although the contribution of concrete in tension is less significant than its contribution in compression, the use of these existing models often leads to overestimating the shear response of reinforced concrete (RC) panels. An improved concrete tension stiffening model incorporating the effect of biaxial stresses is proposed in this study. The effect of tension stiffening on the behaviour of shear panels under normal and shear stresses is investigated by incorporating tension stiffening in the softened membrane model (SMM). The existing SMM algorithm can be used to estimate the behaviour of RC panels subjected only to pure shear. In the proposed analysis using SMM, a new secant-based algorithm is used to estimate the behaviour of RC panels under combined normal and shear loads. Estimates from the proposed model are compared with estimates from original SMM and experimental results. The comparison shows that the proposed model provides better estimates of shear response for RC panels that undergo high shear strains than the original SMM. Furthermore, the proposed secant-based algorithm estimates panel behaviour under combined loading in reduced computational time.
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11,806 members
Yong Bin Kang
  • Department of Media and Communication
Enzo Palombo
  • Department of Chemistry and Biotechnology
Avinash Karpe
  • Department of Chemistry and Biotechnology
Yosry (Yos) Morsi
  • Department of Mechanical Engineering
Peter Gerard Higgins
  • Faculty of Science, Engineering and Technology
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