ORCID Profile
0000-0002-3054-8638
Current Organisation
Australian National University
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Energy Generation, Conversion and Storage Engineering | Nanomaterials | Functional Materials | Nanotechnology not elsewhere classified | Nanotechnology | Mechanical Engineering | Numerical Modelling and Mechanical Characterisation
Hydrogen-based Energy Systems (incl. Internal Hydrogen Combustion Engines) | Solar-Thermal Energy | Hydrogen Storage | Expanding Knowledge in Technology |
Publisher: AIP Publishing
Date: 10-2021
DOI: 10.1063/5.0065125
Abstract: Natural convection arising over vertical and horizontal heated flat surfaces is one of the most ubiquitous flows at a range of spatiotemporal scales. Despite significant developments over more than a century contributing to our fundamental understanding of heat transfer in natural convection boundary layers, certain “hidden” characteristics of these flows have received far less attention. Here, we review scattered progress on less visited fundamental topics that have strong implications to heat and mass transfer control. These topics include the instability characteristics, laminar-to-turbulent transition, and spatial flow structures of vertical natural convection boundary layers and large-scale plumes, dome, and circulating flows over discretely and entirely heated horizontal surfaces. Based on the summarized advancements in fundamental research, we elaborate on the selection of perturbations and provide an outlook on the development of perturbation generators and methods of altering large-scale flow structures as a potential means for heat and mass transfer control where natural convection is dominant.
Publisher: American Physical Society (APS)
Date: 17-11-2020
Publisher: Elsevier BV
Date: 10-2020
Publisher: Elsevier BV
Date: 04-2021
Publisher: Elsevier BV
Date: 02-2020
Publisher: AIP Publishing
Date: 20-08-2013
DOI: 10.1063/1.4817682
Abstract: We have developed a method to measure thermodiffusion and Fickian diffusion in transparent binary solutions. The measuring instrument consists of two orthogonally aligned phase-shifting interferometers coupled with a single rotating polarizer. This high-resolution interferometer, initially developed to measure isothermal diffusion coefficients in liquid systems [J. F. Torres, A. Komiya, E. Shoji, J. Okajima, and S. Maruyama, Opt. Lasers Eng. 50, 1287 (2012)], was modified to measure transient concentration profiles in binary solutions subject to a linear temperature gradient. A convectionless thermodiffusion field was created in a binary solution s le that is placed inside a Soret cell. This cell consists of a parallelepiped cavity with a horizontal cross-section area of 10 × 20 mm2, a variable height of 1–2 mm, and transparent lateral walls. The small height of the cell reduces the volume of the s le, shortens the measurement time, and increases the hydrodynamic stability of the system. An additional free diffusion experiment with the same optical apparatus provides the so-called contrast factors that relate the unwrapped phase and concentration gradients, i.e., the measurement technique is independent and robust. The Soret coefficient is determined from the concentration and temperature differences between the upper and lower boundaries measured by the interferometer and thermocouples, respectively. The Fickian diffusion coefficient is obtained by fitting a numerical solution to the experimental concentration profile. The method is validated through the measurement of thermodiffusion in the well-known liquid pairs of ethanol-water (ethanol 39.12 wt.%) and isobutylbenzene-dodecane (50.0 wt.%). The obtained coefficients agree with the literature values within 5.0%. Finally, the developed technique is applied to visualize biomolecular thermophoresis. Two protein aqueous solutions at 3 mg/ml were used as s les: aprotinin (6.5 kDa)-water and lysozyme (14.3 kDa)-water. It was found that the former protein molecules are thermophilic and the latter thermophobic. In contrast to previously reported methods, this technique is suitable for both short time and negative Soret coefficient measurements.
Publisher: Elsevier BV
Date: 2021
Publisher: American Chemical Society (ACS)
Date: 04-09-2020
Publisher: Cambridge University Press (CUP)
Date: 04-09-2014
DOI: 10.1017/JFM.2014.448
Abstract: Natural convection in an inclined cubical cavity heated from two opposite walls maintained at different temperatures and with adiabatic sidewalls is investigated numerically. The cavity is inclined by an angle $\\def \\xmlpi #1{}\\def \\mathsfbi #1{\\boldsymbol {\\mathsf {#1}}}\\let \\le =\\leqslant \\let \\leq =\\leqslant \\let \\ge =\\geqslant \\let \\geq =\\geqslant \\def \\Pr {\\mathit {Pr}}\\def \\Fr {\\mathit {Fr}}\\def \\Rey {\\mathit {Re}}\\theta $ around a lower horizontal edge and the isothermal wall set at the higher temperature is the lower wall in the horizontal situation ( $\\theta = 0^\\circ $ ). A continuation method developed from a three-dimensional spectral finite-element code is applied to determine the bifurcation diagrams for steady flow solutions. The numerical technique is used to study the influence of ${\\theta }$ on the stability of the flow for moderate Rayleigh numbers in the range $\\mathit{Ra} \\leq 150\\, 000$ , focusing on the Prandtl number $\\mathit{Pr} = 5.9$ . The results show that the inclination breaks the degeneracy of the stable solutions obtained at the first bifurcation point in the horizontal cubic cavity: (i) the transverse stable rolls, whose rotation vector is in the same direction as the inclination vector ${\\boldsymbol{\\Theta}}$ , start from $\\mathit{Ra} \\to 0$ forming a leading branch and becoming more predominant with increasing $\\theta $ (ii) a disconnected branch consisting of transverse rolls, whose rotation vector is opposite to ${\\boldsymbol{\\Theta}}$ , develops from a saddle-node bifurcation, is stabilized at a pitchfork bifurcation, but globally disappears at a critical inclination angle (iii) the semi-transverse stable rolls, whose rotation axis is perpendicular to ${\\boldsymbol{\\Theta}}$ at $\\theta \\to 0^\\circ $ , develop from another saddle-node bifurcation, but the branch also disappears at a critical angle. We also found the stability thresholds for the stable diagonal-roll and four-roll solutions, which increase with $\\theta $ until they disappear at other critical angles. Finally, the families of stable solutions are presented in the $\\mathit{Ra}-\\theta $ parameter space by determining the locus of the primary, secondary, saddle-node, and Hopf bifurcation points as a function of $\\mathit{Ra}$ and $\\theta $ .
Publisher: Elsevier BV
Date: 02-2021
Publisher: Elsevier BV
Date: 11-2023
Publisher: AIP Publishing
Date: 26-04-2022
DOI: 10.1063/5.0088325
Abstract: Thermodiffusion is the migration of a species due to a temperature gradient and is the driving phenomenon in many applications ranging from early cancer detection to uranium enrichment. Molecular dynamics (MD) simulations can be a useful tool for exploring the rather complex thermodiffusive behavior of species, such as proteins and ions. However, current MD models of thermodiffusion in aqueous ionic solutions struggle to quantitatively predict the Soret coefficient, which indicates the magnitude and direction of species migration under a temperature gradient. In this work, we aim to improve the accuracy of MD thermodiffusion models by assessing how well different water models can recreate thermodiffusion in a benchmark aqueous NaCl solution. We tested four of the best available rigid non-polarizable water models (TIP3P-FB, TIP4P-FB, OPC3, and OPC) and the commonly used TIP3P and SPC/E water models for their ability to predict the inversion temperature and Soret coefficient in 0.5, 2, and 4M aqueous NaCl solutions. Each water model predicted a noticeably different ion distribution yielding different inversion temperatures and magnitudes of the Soret coefficient. By comparing the modeled Soret coefficients to published experimental values, we determine TIP3P-FB to be the water model that best recreates thermodiffusion in aqueous NaCl solutions. Our findings can aid future works in selecting the most accurate rigid non-polarizable water model, including water and ion parameters for investigating thermodiffusion through MD simulations.
Publisher: Elsevier BV
Date: 10-2022
Publisher: Research Square Platform LLC
Date: 21-09-2021
DOI: 10.21203/RS.3.RS-919328/V1
Abstract: Concentrating solar thermal (CST) is an efficient renewable energy technology with low-cost thermal energy storage. CST relies on wide-spectrum solar thermal absorbers that must withstand high temperatures ( 700°C) for many years, but state-of-the-art coatings have poor optical stability. Here, we show that the largely overlooked macro-scale morphology is key to enhancing both optical resilience and light trapping. Inspired by stony-coral morphology, we developed a hierarchical coating with three tuneable length-scale morphologies: nano- (~ 120 nm), micro- (~ 3 µm) and macro-scales ( 50 µm). Our coating exhibits outstanding, stable solar-weighted absorptance of 97.75 ± 0.04% after ageing at 850°C for more than 2,000 hours. The scalability of our coating is demonstrated on a commercial solar thermal receiver, paving the way for more reliable high-performance solar thermal systems.
Publisher: Elsevier BV
Date: 12-2019
Publisher: American Physical Society (APS)
Date: 30-10-2013
Publisher: Wiley
Date: 06-06-2021
Abstract: High‐efficiency and wavelength‐tunable light‐emitting diode (LED) devices will play an important role in future advanced optoelectronic systems. Traditional semiconductor LED devices typically have a fixed emission wavelength that is determined by the energy of the emission states. Here, a novel high‐efficiency and wavelength‐tunable monolayer WS 2 LED device, which operates in the hybrid mode of continuous‐pulsed injection, is developed. This hybrid injection enables highly enhanced emission efficiency ( times) and effective size of emission area ( times) at room temperature. The emission wavelength of the WS 2 monolayer LED device can be tuned over more than 40 nm by driving AC voltages, from exciton emission to trion emission, and further to defect emission. The quantum efficiency of defect electroluminescence (EL) emission is measured to be more than 24.5 times larger than that from free exciton and trion EL emission. The separate carrier injection in the LED also demonstrates advantages in allowing defect species to be visualized and distinguished in real space. Those defects are assigned to be negatively charged defects. The results open a new route to develop high‐performance and wavelength‐tunable LED devices for future advanced optoelectronic applications.
Publisher: AIP Publishing
Date: 10-2019
DOI: 10.1063/1.5131038
Publisher: Elsevier BV
Date: 04-2018
Publisher: American Physical Society (APS)
Date: 17-06-2021
Publisher: Trans Tech Publications, Ltd.
Date: 04-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/DDF.297-301.624
Abstract: This paper describes a novel technique to determine mass diffusion coefficients of multi-component system within a transparent mixture by using an optical system. The mixture is composed of sodium chloride and lysozyme as solutes. Binary and multi-component solution experiments were conducted separately under constant temperature conditions. By measuring transient diffusion fields inside the cell, as well as for mixed multi-component solutions, it was confirmed that within the concentration ranges considered in this study, the diffusion of each solute inside the cell progresses independently. This indicates the superposition principle of concentration for certain levels of sodium chloride and lysozyme within the cell. Furthermore, by using this concentration superposition principle and an inverse analysis based on the conjugate gradient method, the diffusion coefficients of each solute in the mixture were successfully obtained from several multi-component experiments. Each obtained diffusion coefficient was good agreement with the determined diffusion coefficient from binary experiment.
Publisher: Elsevier BV
Date: 09-2012
Publisher: Research Square Platform LLC
Date: 30-11-2020
DOI: 10.21203/RS.3.RS-110731/V1
Abstract: High-efficiency and wavelength-tunable light emitting diode (LED) devices will play an important role in future advanced optoelectronic systems. Traditional semiconductor LED devices typically have a fixed emission wavelength that is determined by the energy of the emission states. Here, we developed a novel high-efficiency and wavelength-tunable monolayer WS 2 LED device, which operates in the hybrid mode of continuous-pulsed injection. This hybrid injection enables highly enhanced emission efficiency ( 20 times) and the effective size of emission area ( 5 times) at room temperature. The emission wavelength of WS 2 monolayer LED device can be tuned over more than 40 nm by driving AC voltages, from exciton emission to trion emission, and further to defect emissions. The quantum efficiency of defect electroluminescence (EL) emission is measured to be more than 24.5 times larger than that from free exciton and trion EL emissions. The separate carrier injection in our LED also demonstrate advantage in allowing to visualize and distinguish defect species in real space. Those defects are assigned to be negatively charged defects. Our results open a new route to develop high-performance and wavelength-tunable LED devices for future advanced optoelectronic applications.
Publisher: Wiley
Date: 10-11-2020
Publisher: American Physical Society (APS)
Date: 25-01-2021
Publisher: Elsevier BV
Date: 03-2020
Publisher: Trans Tech Publications, Ltd.
Date: 04-2012
DOI: 10.4028/WWW.SCIENTIFIC.NET/DDF.326-328.452
Abstract: This paper reports the measurement of the binary mass diffusion coefficient for proteins with a wide range of molecular size. The diffusion coefficient is obtained by conducting diffusion experiments in the dilute region. Transient concentration profiles were measured by a phase shifting interferometer and subsequently compared with a numerical calculation based on Ficks law to determine the diffusion coefficient. Distilled water was used as solvent in free diffusion experiments conducted at T = (25 ± 1.0)°C. The method was validated by measuring the diffusion coefficient of aqueous NaCl, Sucrose, and BSA, which values have been extensively reported in the literature. The values of the diffusion coefficient for seven proteins: aprotinin (6.5 kDa), α-lactalbumin (14.2 kDa), lysozyme (14.3 kDa), trypsin inhibitor (20.1 kDa), ovalbumin (44.2 kDa), bovine serum albumin (66.7 kDa), and phosphorylase b (97.2 kDa), were determined in the dilute region of 0-3 mg/ml. The results are compared with the Stokes-Einstein equation. The influence of the molecular structure and pH on the diffusion coefficient is discussed.
Publisher: AIP Publishing
Date: 2019
DOI: 10.1063/1.5117556
Publisher: Elsevier BV
Date: 12-2020
Publisher: Research Square Platform LLC
Date: 23-07-2021
DOI: 10.21203/RS.3.RS-731106/V1
Abstract: Natural convection in air over a heated section-triangular roof with a fixed aspect ratio of 0.1 is experimentally investigated. The development of the flow over the roof subject to a range of temperatures is measured by digital interferometry and thermocouples. The experiments present distinct images of the thermal boundary layer, which changes from a quasi-steady to an unsteady state as the surface temperature of the triangular roof increases. Contrary to numerical simulations previously published, the observed flow becomes unsteady, which is very likely influenced by uncontrolled perturbations at the critical Rayleigh number where a pitchfork bifurcation of a steady flow is theoretically expected.
Publisher: ASMEDC
Date: 2010
DOI: 10.1115/IHTC14-22501
Abstract: In this paper the concentration dependency of mass diffusion coefficients in binary system was investigated. We have developed a novel and accurate visualization system using a small area of transient diffusion fields by adopting a phase shifting technique. Through accurate visualization of the transient diffusion field, it is possible to determine the mass diffusion coefficient. Unlike a conventional interferometer, the proposed system provides high spatial resolution profiles of concentration even though the target area is less than 1.0 mm. This allows the measurement of local transient diffusion field with a high accuracy. The determination of mass diffusion coefficient of each component in multi-component system was also conducted. For the accurate and reliable measurement of mass diffusion coefficient, the experimental error should be taken into account. The experimental data usually contains unexpected accidental error and inherent errors of the measurement system. In this study, an optimization technique using conjugate gradient method is developed for the precise determination of the mass diffusion coefficients. The difference between the experimental and numerical concentration distribution is set as the objective function for the optimization method. The conjugate gradient method searches the optimal value by minimizing the objective function. For the concentration dependency evaluation, sodium chloride (NaCl) in pure water was selected as solute. For determination of each mass diffusion coefficient in multi-component system, NaCl and lysozyme in buffer solution was selected. The experiments were performed under isothermal conditions. The proposed measurement method was validated by comparing the measured data with those available in the literature. The results indicated that the concentration dependency was successfully investigated from the experimental data. The mass diffusion coefficient of each component also could be determined from the experimental data as evidenced by good agreement with the published data. The difference between the reference and determined value of mass diffusion coefficient was less than 10%. It can be said that the diffusion of each solute inside the cell progresses independently within the dilute concentration ranges and the superposition principle of concentration of NaCl and lysozyme was satisfied. The influence of concentration of solution on the diffusion process and allowable concentration range of the superposition principle are determined and discussed.
Publisher: American Physical Society (APS)
Date: 28-08-2015
Publisher: Elsevier BV
Date: 10-2023
Publisher: Elsevier BV
Date: 05-2020
Publisher: Author(s)
Date: 2018
DOI: 10.1063/1.5067075
Publisher: American Chemical Society (ACS)
Date: 15-11-2021
Abstract: Magnetism in two dimensions is one of the most intriguing and alluring phenomena in condensed matter physics. Atomically thin 2D materials have emerged as a promising platform for exploring magnetic properties, leading to the development of essential technologies such as supercomputing and data storage. Arising from spin and charge dynamics in elementary particles, magnetism has also unraveled promising advances in spintronic devices and spin-dependent optoelectronics and photonics. Recently, antiferromagnetism in 2D materials has received extensive attention, leading to significant advances in their understanding and emerging applications such materials have zero net magnetic moment yet are internally magnetic. Several theoretical and experimental approaches have been proposed to probe, characterize, and modulate the magnetic states efficiently in such systems. This Review presents the latest developments and current status for tuning the magnetic properties in distinct 2D van der Waals antiferromagnets. Various state-of-the-art optical techniques deployed to investigate magnetic textures and dynamics are discussed. Furthermore, device concepts based on antiferromagnetic spintronics are scrutinized. We conclude with remarks on related challenges and technological outlook in this rapidly expanding field.
Publisher: AIP Publishing
Date: 2019
DOI: 10.1063/1.5117571
Publisher: Elsevier BV
Date: 04-2019
Publisher: Elsevier BV
Date: 06-2022
Publisher: AIP Publishing
Date: 10-2019
DOI: 10.1063/1.5115073
Abstract: The convective instability of the natural convection boundary layers of air (Pr = 0.7) in the laminar-to-turbulent transition regime (Ra = 8.7 × 107–1.1 × 109) is investigated by stability analysis in the framework of direct numerical simulations. To understand the spatial and temporal evolution of the convective instability of the thermal boundary layers, small- litude random-mode numerical perturbations are first introduced into the boundary condition of the boundary layer flow. The prescribed full spectral perturbations (i.e., white noise) are mostly d ed out immediately by a limited upstream boundary layer. A low-frequency band is initially distinct in the upstream near the leading edge but decays spatially as the instability propagates downstream. In contrast, a high-frequency band emerges to finally become the most dominant frequency band in the thermal boundary layer transition regime. To obtain further insights into the nature of the established high-frequency band, single-mode perturbations of various frequencies are then introduced into the boundary layer near the leading edge. It is found that a single-mode perturbation at the peak frequency within the high-frequency band excites the maximum response of the thermal boundary layer, suggesting that the peak frequency is in fact the characteristic frequency or resonance frequency of the thermal boundary layer. The dimensionless form of the dependence of the characteristic frequency on Ra is then found to be fc = 0.07Ra2/3. The single-mode perturbation numerical experiments also revealed the propagation speed of convective instability waves, which was significantly greater than the convection speed of the thermal boundary layer. The smaller the Ra, the larger the difference between the two propagation speeds. A semi-analytical scaling of the wave propagation speed in the form csc ∼ Ra1/2y1/2Pr was derived (y denoting the streamwise location of the boundary layer), providing a predictive correlation that can be used for thermal boundary layer control.
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D1EE03028K
Abstract: Stony coral morphology inspires ultra-stable sunlight absorber structure with highest reported absorptance for high-temperature solar thermal applications.
Location: No location found
Start Date: 2013
End Date: 2013
Funder: Japan Society for the Promotion of Science
View Funded ActivityStart Date: 2018
End Date: 2020
Funder: Australian Research Council
View Funded ActivityStart Date: 09-2022
End Date: 09-2026
Amount: $654,642.00
Funder: Australian Research Council
View Funded ActivityStart Date: 02-2019
End Date: 12-2023
Amount: $440,000.00
Funder: Australian Research Council
View Funded Activity