Engineering Commons^™

Introduction To The Geant4 Simulation Toolkit, Susanna Guatelli, D Cutajar, Bradley Oborn, Anatoly B. Rosenfeld

Faculty of Engineering - Papers (Archive)

Geant4 is a Monte Carlo simulation Toolkit, describing the interactions of particles with matter. Geant4 is widely used in radiation physics research, from High Energy Physics, to medical physics and space science, thanks to its sophisticated physics component, coupled with advanced functionality in geometry description. Geant4 is widely used at the Centre for Medical Radiation Physics (CMRP), at the University of Wollongong, to characterise and optimise novel detector concepts, radiotherapy treatments, and imaging solutions. This lecture consists of an introduction to Monte Carlo method, and to Geant4. Particular attention will be devoted to the Geant4 physics component, and to the …

Coupling Effects Of Feed Solution Ph And Ionic Strength On The Rejection Of Boron By Nf/Ro Membranes, Kha Tu, Long Nghiem, Allan Chivas

Faculty of Engineering - Papers (Archive)

The coupling effects of solution pH and ionic strength on boron rejection by nanofiltration (NF) and reverse osmosis (RO) membranes were investigated. Two NF membranes (namely NF270 and NF90) and three RO membranes (namely BW30, SW30 and UTC80) were used to provide a full spectrum of NF/RO membranes. The rejection of boron by all five membranes was pH-dependent. The dependency of boron rejection on the feed solution pH became much more substantial as the nominal salt (sodium or calcium) rejection value of the membrane decreased. At pH 11, boron rejections by the NF90 and the NF270 membranes were only 10% …

Treatment Of Saline Aqueous Solutions Using Direct Contact Membrane Distillation, Long Nghiem, Florian Hildinger, Faisal I. Hai, Tzahi Cath

Faculty of Engineering - Papers (Archive)

The treatment of highly saline aqueous solutions using direct contact membrane distillation (DCMD) was evaluated in this study. Experiments were conducted using a flat sheet polytetrafluoroethylene membrane with nominal pore size of 0.22 µm. Seawater, reverse osmosis (RO) concentrate collected from a wastewater reclamation plant, and a synthetic solution containing 2,000 mg/L of CaSO₄ were selected as the representative saline solutions. A gradual decline in permeate flux was observed at the beginning of the experiments when the seawater and RO concentrate solutions were treated using the DCMD process, most likely due to initial organic fouling and scaling. In contrast, …

Magnetocaloric Effect In Layered Ndmn2ge0.4si1.6, Jianli Wang, S.J Campbell, J.M Cadogan, A J Studer, Rong Zeng, S. X. Dou

Faculty of Engineering - Papers (Archive)

A giant magnetocaloric effect has been observed in NdMn₂Ge_0.4Si_1.6 associated with the first-order magnetic phase transition from antiferromagnetism to ferromagnetism around T_C = 36 K. The magnetic entropy change –ΔS_M and adiabatic temperature change ΔT_ad have been determined from magnetization and specific heat measurements (B = 0–5 T) with –ΔS_M calculated by the Maxwell relation and Clausius–Clapeyron method. The values –ΔSMmax = 12.3 J kg⁻¹ K⁻¹ and refrigerant capacity ∼ 95 J/kg for ΔB = 0–2 T as derived from …

Two-Color Terahertz Response In Bilayer Graphene Nanoribbons With Spin-Orbit Coupling, Junfeng Liu, Bo Wang, Zhongshui Ma, Chao Zhang

Faculty of Engineering - Papers (Archive)

We demonstrate that spin-orbit coupling can give rise to a strong terahertz response in metallic armchair bilayer graphene nanoribbons. The combination of the interlayer coupling and the spin-orbit coupling leads to double resonant optical response in the low frequency regime. The frequency separation of the two excitations is tunable with a gate voltage.

Slope Hazard Assessment On A Coast Road In New South Wales, Australia, M. Hendrickx, R A. Wilson, A T. Moon, I E. Stewart, Phillip N. Flentje

Faculty of Engineering - Papers (Archive)

Lawrence Hargrave Drive was constructed in 1878 and has experienced a continuance of slope failures including rock falls, debris flows and embankment collapses. In 2003 a section of the road was closed for safety reasons. An Alliance between the state government and private industry was formed to develop an engineering solution to reduce the risk to ‘acceptable’ levels. Assessment of slope hazards was completed with the aid of geological mapping, interpretation of aerial photographs, archived government reports, historical photo and newspaper collections and a GIS based landslide inventory. Historical photographs provided important evidence on erosion rates and the size, nature …

Treatment Of High Tds Liquid Waste: Is Zero Liquid Discharge Feasible?, Alexander Robertson, Long Nghiem

Faculty of Engineering - Papers (Archive)

A zero liquid discharge treatment system for the disposal of saline industrial liquid waste was proposed and evaluated in this study. Microfiltration was selected as a pretreatment process after a qualitative assessment against `conventional¿ options. Two reverse osmosis (RO) membranes were examined for the pre-concentration of liquid waste using a laboratory scale membrane rig. The results were used to validate the use of the ROSA simulation package. ROSA simulation was conducted with liquid waste having a range of salinity of up to 100,000 ppm of total dissolved solid (TDS). Results reported here indicated that RO membranes were highly suitable for …

Professional Ethics Education In Engineering, Brad Stappenbelt

Faculty of Engineering - Papers (Archive)

There is much debate surrounding professional ethics education, in particular surrounding the question of whether professional ethics can be taught at all (Steneck, 1999; Bauer and Adams, 2005). Professional ethics instruction in engineering is commonly conducted by examining case studies in light of the code of conduct of a suitable professional body. Although graphical presentations of spectacular failures, sobering stories of the repercussions and the solid framework provided by the tenets of a code of ethics may leave a lasting impression, students generally gain their professional identity from relatives and colleagues (Loui, 2005). Their professional ethics tend to be mostly …

Energy-Loss Rate Of A Fast Particle In Graphene, Yee Sin Ang, Chao Zhang, Chun Kee

Faculty of Engineering - Papers (Archive)

The energy-loss rate of a fast particle in graphene is studied. The energy-loss rate always increases with increasing incident particle energy, which is quite unusual when compared to electron gas in normal metal. Graphene exhibits a “discriminating” behavior where there exists a low energy cut-off below which the scattering process is strictly forbidden, leading to lossless traverse of an external particle in graphene. This low energy cutoff is of the order of nearest neighbor hopping bandwidth. Our results suggest that backscattering is also absent in the external particle scattering of graphene.

Flac3d Analysis On Soil Moving Through Piles, E H. Ghee, W D. Guo

Faculty of Engineering - Papers (Archive)

Piles may be utilized as deep foundations or employed to support offshore structures, which may be subjected to passive loading due to lateral soil movements. The safety of the piled foundations depends on the additional stresses induced. This issue has been investigated recently by conducting model tests on single piles and on pile groups with a new apparatus developed by the authors. Typical test results were analysed and reported previously. In this paper three-dimensional finite difference analyses are reported: (1) to predict the results of two model tests (with and without axial load); and (2) to investigate the effect of …

Structure Nonlinearity And Response Of Laterally Loaded Piles, Wei Dong Guo, B T. Zhu

Faculty of Engineering - Papers (Archive)

In light of a generic limiting force profile (LFP), closed·form solutions for laterally loaded free- and fixed- head piles in elastic-plastic media have been developed, and implemented by the first author into a spreadsheet program called GASLFP. The solutions offer an expeditious and sufficiently accurate prediction of response of lateral piles. Conversely, they allow input parameters to be deduced using measured pile response, as has been conducted for over 70 test (elastic) piles to date. Nevertheless. structure nonlinearity of pile body is an important issue at a large deflection.

In this paper, a semi·empirical approach is established to capture pile …

Crystal Plasticity Finite Element Modelling Of Surface Roughness And Texture Of Metals, H Li, Z Jiang, D Wei, J Han

Faculty of Engineering - Papers (Archive)

A crystal plasticity finite element method (CPFEM) model was developed to analyse the surface roughness transfer and texture of metals during metal forming. In order to investigate the crystal slip mechanism and influence of different polycrystalline models (Taylor-type model and finite element polycrystalline model) on finite element modelling, the uniaxial compression of FCC pure aluminum was carried out in laboratory, and the Taylor-type and finite element polyaystalline models are separately employed in the finite element software ABAQUS to simulate the development of the deformation texture by rate dependent crystal constitutive equations during three different deformation modes (free compression, uniaxial planar …

Use Of Geosynthetics In Railways Including Geocomposites And Vertical Drains, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Sanjay Nimbalkar

Faculty of Engineering - Papers (Archive)

Australia relies heavily on rail for the transportation of bulk commodities and passenger services, and has introduced faster and heavier trains in recent years due to a growing demand. Large cyclic loading from heavy haul and passenger trains often leads to progressive deterioration of the track. The excessive deformations and degradations of the ballast layer and unacceptable differential settlement or pumping of underlying soft and compressible subgrade soils necessitate frequent costly track maintenance works. A proper understanding of load transfer mechanisms and their effects on track deformations are essential prerequisites for minimising maintenance costs. The reinforcement of the track by …

Physical And Chemical Ground Improvement For Sustainable Transportation Infrastructure Under Cyclic Loads, Buddhima Indraratna, Cholachat Rujikiatkamjorn, Jayan S. Vinod, Sanjay Nimbalkar

Faculty of Engineering - Papers (Archive)

Railways form one of the major worldwide transportation networks and they continue to provide quick and safe public and freight transportation. In order to compete with other modes of transportation and to meet the ever growing demand of public and freight transport, railway industries face challenges to improve their efficiency and decrease the costs of maintenance and infrastructure. Large cyclic loading from heavy haul and passenger trains often leads to progressive deterioration of the track. The excessive deformations and degradations of the ballast layer and unacceptable differential settlement or pumping of underlying soft and compressible subgrade soils necessitate frequent costly …

Synthesis, Characterization, Dna Interaction And Cleavage, And In Vitro Cytotoxicity Of Copper(Ii) Mixed-Ligand Complexes With 2-Phenyl-3-Hydroxy-4(1h)-Quinolinone, Roman Buchtik, Zdenek Travnicek, Jan Vanco, Radovan Herchel, Zdenek Dvorak

Faculty of Engineering - Papers (Archive)

A series of mixed-ligand complexes [Cu(qui)(L)]NO₃·xH₂O (1–6), where Hqui = 2-phenyl-3-hydroxy-4(1H)-quinolinone, L = 2,2′-bipyridine (bpy) (1), 1,10-phenanthroline (phen) (2), bis(2-pyridyl)amine (ambpy) (3), 5-methyl-1,10-phenanthroline (mphen) (4), 5-nitro-1,10-phenanthroline (nphen) (5) and bathophenanthroline (bphen) (6), have been synthesized and fully characterized. The X-ray structures of [Cu(qui)(phen)]NO₃·H₂O (2) and [Cu(qui)(ambpy)]NO₃ (3a) show a slightly distorted square-planar geometry in the vicinity of the central copper(II) atom. An in vitro cytotoxicity study of the complexes …

Preliminary Evaluations On Laser - Tandem Gmaw, Ruham P. Reis, John Norrish, Dominic Cuiuri

Faculty of Engineering - Papers (Archive)

Recently there has been considerable research and development activity in the use of lasers for welding operations, turning this process into an important tool for a variety of applications. Although it is possible to use lasers as a unique source of heat to promote union of materials, the combination of the beam provided by a laser system with an arc welding process has been studied widely and applied in the so-called hybrid welding systems. Generally, the final result of such a combination is an increase in the weld penetration depth, width and welding travel speed. Despite these advantages, there are …

Practical Reliability Approach To Urban Slope Stability, R. Chowdhury, P. Flentje

Faculty of Engineering - Papers (Archive)

Assessing urban slope stability requires consideration of significant uncertainties including those associated with shear strength and pore water pressure. For site-specific studies, there is considerable merit in adopting a reliability approach within a probabilistic framework based on widely accepted geotechnical models. Regional slope stability studies are facilitated by using a GIS-based approach. Considerable effort is required to prepare regional data sets including topography and geology and to develop a landslide inventory. Reference is made to a comprehensive knowledge-based approach for assessing failure susceptibility and hazard within an urban region in Australia. Each hazard zone is associated with an estimated likelihood …

Experimental Study On The Effectiveness Of Prefabricated Vertical Drains Under Cyclic Loading, Cholachat Rujikiatkamjorn, Buddhima Indraratna, Guanghui Meng

Faculty of Engineering - Papers (Archive)

This study is an attempt to investigate the effectiveness of a prefabricated vertical drain (PVD) installed in remoulded soft clay, where a large-scale cyclic triaxial process simulation rig was employed to simulate cyclic loading representing a track environment. The experimental data show that PVD successfully prevents excessive accumulation of pore water pressure during cyclic loading, and their dissipation continues to occur after the load is removed. The findings of this study have direct significance to rail track environments, e.g. in coastal Australia, where PVD installation beneath rail tracks constructed on low-lying estuarine soils has been recently adopted.

Advanced Directional Drilling Technology For Gas Drainage And Exploration In Australian Coal Mines, Fangtian Wang, Ting Ren, Frank Hungerford, Shihao Tu, Najdat I. Aziz

Faculty of Engineering - Papers (Archive)

With the continuing technology innovation, directional drilling technology has provided the coal mining industry with effective and practical options for pre- and post-drainage and exploration in Australia. In the past thirty years, in-mine borehole steering equipment has been developed from the single shot camera survey systems to the advanced Directional Drill Monitor utilizing Modular Electrically Connected Cable Assembly (DDM-MECCA) survey instruments, which provides rapid and easy underground borehole survey measurements whilst drilling. The presence of coal seam gas such as methane poses a significant safety hazard to underground coal mining all over the world. However, gas can be captured using …

Direct Observation Of Local Potassium Variation And Its Correlation To Electronic Inhomogeneity In (Ba1-Xkx)Fe2as 2 Pnictide, Wai Kong Yeoh, Baptiste Gault, X.Y. Cui, C. Zhu, P Moody, L. Li, Rongkun Zheng, Wenxian Li, Xiaolin Wang, S. X. Dou, G.L Sun, C T Lin, S P. Ringer

Faculty of Engineering - Papers (Archive)

Local fluctuations in the distribution of dopant atoms are thought to cause the nanoscale electronic disorder or phase separation in pnictide superconductors. Atom probe tomography has enabled the first direct observations of dopant species clustering in a K-doped 122-phase pnictide. First-principles calculations suggest the coexistence of static magnetism and superconductivity on a lattice parameter length scale over a wide range of dopant concentrations. Our results provide evidence for a mixed scenario of phase coexistence and phase separation, depending on local dopant atom distributions.