Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 14 of 14
Full-Text Articles in Engineering
Effect Of Grain Size On The Hydrogen Diffusion Process In Steel Using Cellular Automaton Approach, Druce P. Dunne, E V. Pereloma, Nima Yazdipour
Effect Of Grain Size On The Hydrogen Diffusion Process In Steel Using Cellular Automaton Approach, Druce P. Dunne, E V. Pereloma, Nima Yazdipour
Faculty of Engineering - Papers (Archive)
The role of microstructure in susceptibility to hydrogen uptake and property degradation is being evaluated using a number of high strength pipeline steels. To do so, a cellular automaton (CA) model has been used to examine the effect of grain size, as a first step in assessing the influence of microstructure. The simulation results of hydrogen diffusion into microstructures with different grain sizes are presented.
Effect Of Gas Atmosphere On Carbothermal Reduction And Nitridation Of Titanium Dioxide, Sheikh A. Rezan, Guangqing Zhang, Oleg Ostrovski
Effect Of Gas Atmosphere On Carbothermal Reduction And Nitridation Of Titanium Dioxide, Sheikh A. Rezan, Guangqing Zhang, Oleg Ostrovski
Faculty of Engineering - Papers (Archive)
This article examined the reduction/nitridation of rutile in the He-N2, Ar-N2, and He (Ar)-H2- N2 gas mixtures, as well as pure nitrogen, in the temperature-programmed and isothermal experiments in a fixed-bed reactor. The extents of reduction and nitridation were determined from the off gas composition and LECO analysis. The off-gas composition was monitored using the infrared sensor (CO, CO2, and CH4) and dew point analyzer (H2O). The phase composition of the reduced samples was analyzed using X-ray diffraction (XRD). The temperature and gas composition had a strong effect on the rutile reduction. The reduction was the fastest in the H2- …
Effect Of Compaction Energy On Shear Wave Velocity Of Dynamically Compacted Silty Sand Soil, Buddhima Indraratna, Ana Heitor, Cholachat Rujikiatkamjorn
Effect Of Compaction Energy On Shear Wave Velocity Of Dynamically Compacted Silty Sand Soil, Buddhima Indraratna, Ana Heitor, Cholachat Rujikiatkamjorn
Faculty of Engineering - Papers (Archive)
This study was focused on the effects of compaction energy on the dynamic properties of a silty sand in its as-compacted state in relation to the measured values of matric suction. The influence of the imparted energy on the shear wave velocity and the small-strain shear modulus of the compacted soil was studied for three different energy levels that correspond to the standard Proctor as well as reduced and enhanced. The specimens were prepared with moisture contents ranging from the dry to wet of optimum, and subsequently compacted to known dry unit weights for which the corresponding matric suction and …
Radial Consolidation Modelling Incorporating Downdrag Effect For A Multi-Layer Soil, Cholachat Rujikiatkamjorn, Buddhima Indraratna
Radial Consolidation Modelling Incorporating Downdrag Effect For A Multi-Layer Soil, Cholachat Rujikiatkamjorn, Buddhima Indraratna
Faculty of Engineering - Papers (Archive)
A system of vertical drains (PVDs) with preloading is a successful method for promoting horizontal drainage and accelerating soil consolidation. A piecewise technique is used to capture the radial consolidation in the multi-layer soil system to incorporate (a) the effect of soil downdrag and (b) smear zone where soil permeability varying linearly. The effect of soil dragged down from the upper soil layer into the lower layer has been analysed in terms of required time for consolidation. It can be seen that the consolidation of the multi layer soil depends on the interaction between 2 adjacent layer, penetration depth, and …
Effect Of Coal Fines On The Shear Strength And Deformation Characteristics Of Ballast, S S. Nimbalkar, Buddhima Indraratna, Cholachat Rujikiatkamjorn, M Martin
Effect Of Coal Fines On The Shear Strength And Deformation Characteristics Of Ballast, S S. Nimbalkar, Buddhima Indraratna, Cholachat Rujikiatkamjorn, M Martin
Faculty of Engineering - Papers (Archive)
Ballast is the most common material supporting the rail track structure due to its large shear strength, high load bearing capacity and free-drainage. However, the fouling of ballast effects deterioration of track performance, and eventually demands track cleaning. Fouling refers to the progressive intrusion of fines into the ballast layer and subsequently filling the voids. Coal spilling from wagons during transport, sleeper and ballast degradation and soil pumping from soft subgrade are the major factors contributing to ballast fouling. Queensland rail network suffers mainly due to ballast breakdown and intrusion of coal fines. The maintenance costs of ballasted tracks can …
The Effect Of The Strain Rate On Soft Soil Behaviour Under Cyclic Loading, Jing Ni, Buddhima Indraratna, X Y. Geng, Cholachat Rujikiatkamjorn
The Effect Of The Strain Rate On Soft Soil Behaviour Under Cyclic Loading, Jing Ni, Buddhima Indraratna, X Y. Geng, Cholachat Rujikiatkamjorn
Faculty of Engineering - Papers (Archive)
In this paper, cyclic triaxial loading tests were conducted on specimens of soft clay with varying cyclic stresses and frequencies to investigate the performance of soft soil subgrade subjected to cyclic loading. The laboratory results indicate that given the same level of cyclic stress, the stability of clay subgrade is primarily dependent on the loading time with no consistent frequency/train speed effect. There exists a critical level of cyclic stress between 60 and 80% of the monotonic shear strength, above which failure may occur regardless of the loading frequency. The nature that soils behave dependently on cyclic stress level rather …
Effect Of Annealing On The Microstructure, Texture And Mechanical Properties Of Severely Deformed Interstitial Free Steel, Sujoy S. Hazra, Azdiar A. Gazder, E V. Pereloma
Effect Of Annealing On The Microstructure, Texture And Mechanical Properties Of Severely Deformed Interstitial Free Steel, Sujoy S. Hazra, Azdiar A. Gazder, E V. Pereloma
Faculty of Engineering - Papers (Archive)
Ti-stabilised interstitial free (IF) steel initially subjected to 8 passes, route BC equal channel angular pressing (ECAP) was further cold rolled (CR) at room temperature to 95% thickness reduction. Both samples were isothermally annealed at 710 °C following which their microstructures and micro-textures were compared via electron back-scattering diffraction (EBSD). The mechanical properties first obtained by shear punch testing (SPT) were later corroborated by uniaxial tensile tests. In the case of the ECAP material, continuous recrystallisation is followed by abnormal growth at prolonged annealing times with minor increases in high angle boundary (HAGB) fraction. On the other hand, the …
The Effect Of Reduced Graphene Oxide Addition On The Superconductivity Of Mgb2, K S. B De Silva, S Gambhir, Xiaolin Wang, X Xu, W X. Li, David L. Officer, D Wexler, G G. Wallace, S. X. Dou
The Effect Of Reduced Graphene Oxide Addition On The Superconductivity Of Mgb2, K S. B De Silva, S Gambhir, Xiaolin Wang, X Xu, W X. Li, David L. Officer, D Wexler, G G. Wallace, S. X. Dou
Faculty of Engineering - Papers (Archive)
Reduced graphene oxide (rGO) and highly reduced chemically converted graphene (ICCO) samples were prepared under different processing condition! and were doped into MgBz by a diffusion process at 800 °C for 10 houn. It was demonstrated that a small addition rCCG can significantly improve the supcn;onducting properties of MgBz. Doping of M8B2 with 1 mol% of rCCG resulted in a Ie of 5.45 X lOS A cm-2 at 20 K in self-fields, which il nearly 32% improvement over that of the undopcd sample. This is a significant improvement as most carbon sources adversely affect the Ie performance: at the zero …
Terahertz Photon Mixing Effect In Gapped Graphene, Yee Sin Ang, Shareef Sultan, Asya Tawfiq, Juncheng Cao, Chao Zhang
Terahertz Photon Mixing Effect In Gapped Graphene, Yee Sin Ang, Shareef Sultan, Asya Tawfiq, Juncheng Cao, Chao Zhang
Faculty of Engineering - Papers (Archive)
We theoretically calculate the terahertz waves mixing effect in doped graphene with a finite bandgap. The temperature dependence of the nonlinear intraband optical response at bandgap opening of few tens of meVare investigated. When the external electric field is weak, a moderate level of bandgap opening is found to slightly enhance the nonlinear optical response. The optical response is however significantly altered under strong-field condition. The strong-field nonlinear optical conductivity exhibits two distinct response ‘hot spot’: (i) low temperature with large bandgap and (ii) high temperature with small bandgap. The electric field required for the nonlinear response to dominate over …
"Oxygen-Vacancy Effect On Structural, Magnetic, And Ferroelectric Properties In Multiferroic Ymno3 Single Crystals", Dapeng Chen, Yi Du, Xiaolin Wang, Zhenxiang Cheng, S. X. Dou, Zhi W. Lin, Jian G. Zhu, Bo Xu
"Oxygen-Vacancy Effect On Structural, Magnetic, And Ferroelectric Properties In Multiferroic Ymno3 Single Crystals", Dapeng Chen, Yi Du, Xiaolin Wang, Zhenxiang Cheng, S. X. Dou, Zhi W. Lin, Jian G. Zhu, Bo Xu
Faculty of Engineering - Papers (Archive)
"We have investigated the structural, magnetic, and ferroelectric properties of magnetically frustrated multiferroic YMnO3 single crystals. The ferroelectric domain structures of YMnO3 samples were studied by piezoresponse force microscopy. Instead of domain vortex structure in stoichiometric crystals, YMnO3-delta exhibits a random domain configuration with straight domain walls. In magnetic measurements, the YMnO3-delta crystal shows typical antiferromagnetic behavior with higher Neel temperature and lower magnetization compared to the stoichiometric sample. The ordered oxygen vacancies dominate multiferroicity through tailoring the domain wall structure. (C) 2012 American Institute of Physics. [doi:10.1063/1.3676000]"
Effect Of A Static Magnetic Field On Nanodosimetric Quantities In A Dna Volume, Peter Lazarakis, Marion U. Bug, Elisabetta Gargioni, Susanna Guatelli, Sabastien Incerti, Hans Rabus, Anatoly B. Rosenfeld
Effect Of A Static Magnetic Field On Nanodosimetric Quantities In A Dna Volume, Peter Lazarakis, Marion U. Bug, Elisabetta Gargioni, Susanna Guatelli, Sabastien Incerti, Hans Rabus, Anatoly B. Rosenfeld
Faculty of Engineering - Papers (Archive)
Abstract Purpose: With the advent of magnetic resonance imaging (MRI)-guided radiation therapy it is becoming increasingly important to consider the potential influence of a magnetic field on ionising radiation. This paper aims to study the effect of a magnetic field on the track structure of radiation to determine if the biological effectiveness may be altered. Methods: Using the Geant4-DNA (GEometry ANd Tracking 4) Monte Carlo simulation toolkit, nanodosimetric track structure parameters were calculated for electrons, protons and alpha particles moving in transverse magnetic fields up to 10 Tesla. Applying the model proposed by Garty et al., the track structure parameters …
Magnetovolume Effect In Ho2fe17-Xmnx Compounds, Jianli Wang, A J. Studer, S J. Kennedy, R Zeng, S. X. Dou, S J. Campbell
Magnetovolume Effect In Ho2fe17-Xmnx Compounds, Jianli Wang, A J. Studer, S J. Kennedy, R Zeng, S. X. Dou, S J. Campbell
Faculty of Engineering - Papers (Archive)
The structural and magnetic properties of seven compounds in the Ho2Fe17-xMnx series (x = 0-5) have been investigated. The spontaneous magnetization Ms at 10 K exhibits a minimum at x ≈ 3.8 while the 3d-sublattice magnetization MT is found to decrease at ∼ −3.4 μB/per Mn atom compared with the rate of ∼−2.0 μB/per Mn atom expected from a simple dilution model. All of the Ho2Fe17-xMnx compounds exhibit anisotropic thermal expansion below their Curie temperatures leading to the presence of strong magnetovolume …
Abnormal Magnetic Behaviors And Large Magnetocaloric Effect In Mnps3 Nanoparticles, R Zeng, S Q. Wang, G D. Du, Jianli Wang, J C. Debnath, Precious Shamba, Z Y. Fang, S. X. Dou
Abnormal Magnetic Behaviors And Large Magnetocaloric Effect In Mnps3 Nanoparticles, R Zeng, S Q. Wang, G D. Du, Jianli Wang, J C. Debnath, Precious Shamba, Z Y. Fang, S. X. Dou
Faculty of Engineering - Papers (Archive)
A nanostructured honeycomb lattice consisting of MnPS3 nanoparticles synthesized via the ion-exchange technique was found to have restacked molecular layers stabilized by H2O insertion between the layers. Susceptibility (χ) and heat capacity measurements showed the absence of long range magnetic ordering, at least down to 2 K. However, the χ data showed that the system possesses a high effective Curie temperature, suggesting that the system is in a high spin lattice disordered state. Evaluation of the magnetocaloric effect indicates that the system has a large reversible magnetic-entropy change (−ΔSm) of 6.8 and 12.8 J/kg K …
Probing And Modelling The Localized Self-Mixing In A Gan/Algan Field-Effect Terahertz Detector, J D. Sun, H Qin, R A. Lewis, Y F. Sun, X Y. Zhang, Y Cai, D M. Wu, B S. Zhang
Probing And Modelling The Localized Self-Mixing In A Gan/Algan Field-Effect Terahertz Detector, J D. Sun, H Qin, R A. Lewis, Y F. Sun, X Y. Zhang, Y Cai, D M. Wu, B S. Zhang
Faculty of Engineering - Papers (Archive)
In our previous work, we inferred the existence of localized self-mixing in an antenna-coupled field-effect terahertz detector. In this Letter, we report a quasistatic self-mixing model taking into account the localized terahertz fields and its verification by comparing the simulated results with the experimental data in a two-dimensional space of the gate voltage and the drain/source bias. The model well describes the detector characteristics: not only the magnitude, but also the polarity, of the photocurrent can be tuned. The existence of strongly localized self-mixing in such detectors is confirmed.