Engineering Commons^™

Proposal For A New Class Of Materials: Spin Gapless Semiconductors, Xiaolin Wang

Australian Institute for Innovative Materials - Papers

The concept of the spin gapless semiconductor in which both electron and hole can be fully spin polarized is proposed, and its possibility is presented on the basis of first-principles electronic structure calculations. Possible new physics and potential applications in spintronic devices based on the spin gapless semiconductors are discussed.

Flux-Pinning Mechanism In Silicone-Oil Doped Mgb2: Evidence For Charge-Carrier Mean Free Path Fluctuation Pinning, Shaban R. Ghorbani, Xiaolin Wang, S X. Dou, Sung-Ik Lee, Md S. Hossain

Australian Institute for Innovative Materials - Papers

Flux-pinning mechanism of MgB₂ doped with 10 wt % silicone-oil sintered at low and high temperatures has been investigated by magnetic measurements. The field dependence of the critical current density, j_c(B), was analysed within the collective pinning model. A crossover field, B_sb, from the single vortex to the small vortex bundle-pinning regime was observed. For both types of sintered samples, the temperature dependence of B_sb(T) at low temperature is in good agreement with the δl pinning mechanism, i.e., pinning associated with charge-carrier mean free path fluctuation. At temperatures close to the critical …

Cfd Analysis Of The Performance Of Blade Cascades For Air Turbines In Oscillating Water Column Wave Energy Conversion Systems, Andrei Gareev, Paul Cooper, Prabuono B. Kosasih

Faculty of Engineering - Papers (Archive)

This paper presents the results of a detailed CFD (Computational Fluid Dynamics) analysis of the performance of blade cascades in reversing flow axial flow turbines for use as power take-off systems in Oscillating Water Column (OWC) Wave Energy Conversion (WEC) systems. In the first part of the paper a fundamental CFD analysis of the lift and drag data for various aerofoil profiles, using a number of different turbulence models, is described and quantitative comparisons are made with experimental data previously published by other researchers. The second part of the paper then describes CFD results of the performance of various rotors …

Experimental Investigation Of Load-Deformation Response For Blast-Resistant Facade Glazing Solutions, Alexander Remennikov, Luke Chipperfield, Nathan Mcinerney

Faculty of Engineering - Papers (Archive)

One of the major causes of injury and loss of life in structures subjected to blast loading is the glass windows. Common window glass is annealed glass. When annealed glass is subjected to impulsive loads such as the one generated by a blast, it breaks into relatively large shards with sharp cutting edges. This is responsible for for most of the injuries incurred in explosions. In the bombing of the Alfred P. Murrah Federal Building in Oklahoma City in 1995, more than 75% of the injuries were due to flying shards of glass.

The current approach to testing blast-resistant glazing …

Study On A Magnetorheological Fluid Bladder Spring For Isolation System, Xianzhou Zhang, Weihua Li, Xingyu Wang

Faculty of Engineering - Papers (Archive)

Vibration reduction and isolation plays an important role in protecting machinery and structures from unwanted vibration related problems. A variety of passive and active isolation systems have been developed for vibration suppression. However, passive systems are only effective for narrow frequencies while passive systems usually have high costs.

Synthesis And Characterization Of Srbi4ti4o15 Ferroelectric Filler Based Composite Polymer Electrolytes For Lithium Ion Batteries, Devaraj Shanmukaraj, Guoxiu Wang, Hua-Kun Liu, R Murugan

Faculty of Engineering - Papers (Archive)

Composite polymer electrolytes (CPEs) based on poly (ethylene oxide) (PEO) (Mol.Wt similar to 6 x 10(5)) complexed with LiN(CF3SO2)(2) lithium salt and SrBi4Ti4O15 ferroelectric ceramic filler have been prepared as films. Citrate gel technique and conventional solid state technique were employed for the synthesis of the ferroelectric fillers in order to study the effect of particle size of the filler on ionic conductivity of the polymer electrolyte. Characterization techniques such as X-ray diffraction (XRD), differential thermal analysis (DTA), scanning electron microscopy (SEM) and temperature dependant DC conductivity studies were taken for the prepared polymer composite electrolytes. The broadening of DTA …

Nico2o4/C Nanocomposite As A Highly Reversible Anode Material For Lithium-Ion Batteries, Yanna Nuli, Peng Zhang, Zaiping Guo, Hua-Kun Liu, Jun Yang

Faculty of Engineering - Papers (Archive)

A NiCo₂O₄/C nanocomposite has been synthesized by a hydrothermal method followed by a calcination. X-ray powder diffraction and transmission electron microscopy measurements demonstrated the composite was composed of crystalline NiCo₂O₄ and amorphous carbon, and NiCo₂O₄ and carbon particles amalgamated together with good affinity. The electrochemical results showed as high as 914.5 mAh/g reversible capacity could be achieved at 40 mA/g current density in the potential range of 0.01-3.0 V. The initial coulombic efficiency of the composite was 79.2%, and the capacity retention was 78.3% up to 50 cycles. The superior …

Chemical Solution Deposition Of Lamno3-Based Films For Coated Conductors, Dongqi Shi, Xuebin Zhu, Jung Ho Kim, Hechang Lei, Lin Wang, Yuping Sun, Rong Zeng, S. X. Dou

Faculty of Engineering - Papers (Archive)

LaMnO3-based films were prepared using the chemical solution deposition method. It was found that the films on perovskite oxide single crystal substrates are highly (h00)-oriented when the annealing atmosphere is oxygen or air; however, when the substrate is yttrium-stabilized ZrO2, only the La1-NmO3 films are highly (h00)-oriented, and other LaMnO3-based films are (110)-oriented. Under a reducing annealing atmosphere, the atmosphere must be wet in order to create a suitable oxygen partial pressure to crystallize the LaMnO3-based films. After annealing under a wet reducing atmosphere the LaMnO3-based films are directly deposited on Ni tapes; however, when SrTiO3-buffered Ni types are used, …

Cross-Institutional Comparison Of Mechanics Examinations: A Guide For The Curious, Thomas Goldfinch, Anna L. Carew, Anne Gardner, Alan Henderson, Timothy J. Mccarthy, Giles Thomas

Faculty of Engineering - Papers (Archive)

This paper describes a process used for, and interim findings of a comparison of final mechanics exam papers for first year engineering mechanics courses at the University of Wollongong, the University of Tasmania, the University of Technology, Sydney, and the Australian Maritime College. The process developed for the purpose emphasized a transparent and sequenced approach to comparing the concepts included in each exam paper, as well as the level of difficulty of exam questions. The exercise was carried out remotely, using readily available communications technology, including telephone, email, and Skype teleconferencing. This process is an example of a simple, easy …

Shape Evolution Of Α-Fe2o3 And Its Size-Dependent Electrochemical Properties For Lithium-Ion Batteries, Yanna Nuli, Peng Zhang, Zaiping Guo, Hua-Kun Liu

Faculty of Engineering - Papers (Archive)

Crystalline α-Fe2O3 with different particle shapes and sizes was selectively synthesized by a simple hydrothermal method. By carefully tuning the concentration of the reactants and the reaction time, α-Fe2O3 cuboid particles and nanowires can be obtained. Based on the evidence of electron microscope images, a shape evolution mechanism for the nanowire structure is proposed. Electrochemical performance as an anode material for lithium-ion batteries was further evaluated by cyclic voltammetry, electrochemical impedance, and charge–discharge measurements. It was demonstrated that both the morphology and the particle size had an influence on the performance. Compared with the electrode made from the …

Design Of Silos For Flow And Strength - The Various Contributors Must Communicate, Peter C. Arnold

Faculty of Engineering - Papers (Archive)

Too often in the design of silo systems for the storage and handling of bulk solids those involved in the various components of the design process do not communicate. The chemical engineers often have a range of desired outcomes that differ from those of the mechanical engineers and the mechanical and structural engineers are often not aiming for the same range of outcomes. Even if all the designers communicate well the overall result may disappoint if the project manager allows significant (but sometimes subtle) design variations during construction. The result can be a system that does not perform well. Had …

An Alternative Rail Pad Tester For Measuring Dynamic Properties Of Rail Pads Under Large Preloads, Sakdirat Kaewunruen, Alexander Remennikov

Faculty of Engineering - Papers (Archive)

One of the main components in ballasted railway track systems is the rail pad. It is installed between the rail and the sleeper to attenuate wheel/rail interaction loads, preventing the underlying railway sleepers from excessive stress waves. Generally, the dynamic design of tracks relies on the available data, which are mostly focused on the structural condition at a specific toe load. Recent findings show that track irregularities could significantly amplify the loads on railway tracks. This phenomenon gives rise to a concern that the rail pads may experience higher effective preloading than anticipated in the past. On this ground, this …

Electrochemical Deposition Of Porous Co(Oh)2 Nanoflake Films On Stainless Steel Mesh For Flexible Supercapacitors, Shulei Chou, Jiazhao Wang, Hua-Kun Liu, S. X. Dou

Faculty of Engineering - Papers (Archive)

Flexible porous Co(OH)2 nanoflake films were prepared by galvanostatic electrodeposition on lightweight and inexpensive stainless steel mesh. The as-prepared porous Co(OH)2 nanoflake films were characterized by X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy. Electrochemical tests including cyclic voltammetry, constant current charge-discharge, and electrochemical impedance spectroscopy were also used to investigate the electrochemical performance. The results show that the highest capacitance is 609.4 F g-1, the specific capacitance decreases by less than 5% as the mass loading of Co(OH)2 increases by more than 340%, and the specific capacitance only decreases by less than 15% when the current densities increase up …