Engineering Commons^™

Numerical Simulation Of Convection In Triangular Cavities To Predict Solar Still Performance, Jeremy D. Lefevre, W. Jerry Bowman, Matthew R. Jones

Faculty Publications

To improve modeling of solar still behavior, the convection correlations currently used need to be improved upon. Variations in operating parameters and cover geometries make it difficult to use a single correlation to describe the operation of all solar stills. In this work, three right triangles (representing covers at 15, 30, and 45 deg) were modeled, meshed, and solved to predict the convection heat transfer inside for a variety of operating conditions. For a correlation of the form Nu = C · Raⁿ, it was found that C = 1.1, 0.60, and 0.71, and n = 0.19, 0.24, …

Performance Of Solid Oxide Iron-Air Battery Operated At 550°C, Xuan Zhao, Yunhui Gong, Xue Li, Nansheng Xu, Kevin Huang

Faculty Publications

“Metal-air” batteries have garnered much attention in recent years due to their high intrinsic specific energy and use of inexhaustible and storage-free oxygen source -air- for the “metal-oxygen” reaction. In this study, we report theperformance of a new type of all solid-state “iron-air” battery operated at 550°C. The results show that CeO₂ nanoparticles incorporated into the Fe-Fe₃O₄ redox-couple can improve the specific energy (Wh/kg) and round trip efficiency by 15% and 29%, respectively, over the baseline Fe-Fe₃O₄ battery. Use of supported Fe-Fe₃O₄ nanoparticles as the redox couple can increase the …

Design Of Experimental Methods To Test The Performance Of Pads And Helmets Under Blast Loading Conditions, Kurtis Palu

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Improvised explosive devices (IEDs) have become a primary weapon in conflicts against US and allied forces. Improvements in body armor and medicine have increased the survivability of such events. These factors have caused an increase in traumatic brain injury (TBI) and mild traumatic brain injury (mTBI) induced by primary blast waves. Injury mechanisms caused from primary blast waves are not clearly understood or defined. How primary blast waves interact with materials or between narrow gaps found between helmet pads is not known. Two novel test fixtures were developed to provide a basic understanding of these two issues.

The first fixture …

Synergetic Combination Of Limd With Chpd For The Production Of Economical And High Performance Mgb2 Wires, Minoru Maeda, Md Shahriar Ai Hossain, Ashkan Motaman, Jung Ho Kim, Anna Kario, Matt Rindfleisch, Mike Tomsic, S X. Dou

Australian Institute for Innovative Materials - Papers

We propose an economical fabrication concept, the localized internal magnesium diffusion (IMD) method. Instead of using a single magnesium (Mg) rod in the center of a metal sheath tube, we use large-sized Mg particles (20-50 mesh) mixed well with cheap 97% crystalline boron powder to fill the metal sheath tube. After a repeated drawing process, the coarse Mg is elongated along the core wire axis of the metal sheath tube. Textured MgB2 grains are then formed during the sintering process. In the localized IMD process, however, there is still a need to improve the overall density. In order to increase …

A Significant Improvement In Both Low- And High-Field Performance Of Mgb2 Superconductors Through Graphene Oxide Doping, K S B De Silva, S H Aboutalebi, Xun Xu, Xiaolin Wang, W X Li, Konstantin Konstantinov, S X. Dou

Australian Institute for Innovative Materials - Papers

The effects of graphene oxide (GO) doping on the superconducting properties of MgB2 were studied using bulk samples made by the diffusion method. Homogeneous dispersions of GO in tetrahydrofuran were obtained through a novel synthesis method, which is then chemically doped with MgB2. It was found that GO doping significantly improves the critical current density, under both low and high magnetic fields, which distinguishes GO from all the other elements doped into MgB2 so far. 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

A Facile Route To Synthesize Transition Metal Oxide/Reduced Graphene Oxide Composites And Their Lithium Storage Performance, Chongjun Zhao, Shulei Chou, Yunxiao Wang, Cuifeng Zhou, Hua-Kun Liu, S X. Dou

Australian Institute for Innovative Materials - Papers

Transition metal oxide (Mn3O4, Fe2O3, Co3O4, and ZnO) and reduced graphene oxide (RGO) composites were successfully synthesized via a hydrothermal method using the direct reaction between the corresponding metal powder and graphene oxide (GO). In this process, the GO can be reduced by transition metal powder in water, and the nanosized metal oxide can be obtained, and homogeneously mixed with and wrapped by RGO to form a metal oxide/RGO composite at the same time. X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning and transmission electron microscopy were used to characterize the as-prepared materials. The different experimental parameters, including reactants, …

Simple Synthesis Of Yolk-Shelled Znco2o4 Microspheres Towards Enhancing The Electrochemical Performance Of Lithium-Ion Batteries In Conjunction With A Sodium Carboxymethyl Cellulose Binder, Jingfa Li, Jiazhao Wang, David Wexler, Dongqi Shi, Jianwen Liang, Hua-Kun Liu, Shenglin Xiong, Yitai Qian

Australian Institute for Innovative Materials - Papers

Mixed metal oxides have been attracting more and more attention recently because of their advantages and superiorities, which can improve the electrochemical performance of single metal oxides. These advantages include structural stability, good electronic conductivity, and reversible capacity. In this work, uniform yolk-shelled ZnCo2O4 microspheres were synthesized by pyrolysis of ZnCo-glycolate microsphere precursors which were prepared via a simple refluxing route without any precipitant or surfactant. The formation process of the yolk-shelled microsphere structure during the thermal decomposition of ZnCo-glycolate is discussed, which is mainly based on the heterogeneous contraction caused by non-equilibrium heat treatment. The performances of the as-prepared …

A General Performance Model For Mac Layer Cooperative Retransmission Contention Protocols, Brett Hagelstein, Mehran Abolhasan, Daniel Franklin, Farzad Safaei

Faculty of Engineering and Information Sciences - Papers: Part A

Cooperative retransmission schemes can significantly improve transmission reliability and performance over high loss and time-varying links. However, analytically comparing performance between retransmission strategies is challenging and generally requires simplistic assumptions. This paper presents a general model for the performance of distributed, slot-based contention algorithms for opportunistic decode and forward retransmission algorithms. The model is independent of specific modulation or coding schemes and may be adapted to suit state-based transmission probability models. The model is validated through QualNet simulations.

Performance Uniformity Evaluation Of Two Sensl's Sipm Modules, Lachlan Chartier, Yujin Qi, Marco Petasecca, Peter Ihnat, Michael L. F Lerch, Anatoly B. Rosenfeld, Benjamin Tsui

Faculty of Engineering and Information Sciences - Papers: Part A

Minimization of the channel-to-channel variation of silicon photomultiplier (SiPM) array is of great importance in achieving high performance for SiPM based imaging detectors. The purpose of this study was to characterize the operating parameters of a large-area SiPM based detector module with 12x12 pixel array (SensL's ArraySM-4P9) in order to develop an optimal multiplexing readout for high-resolution SPECT imaging. Two versions of SensL's SiPM arrays were investigated in this study. The previous ArraySL-4 version has an array of 4x4 pixels with 3x3mm2 pixel size and the new AarraySM-4p9 version consists of a 3x3 matrix of the 4x4 pixels SiPM modules. …

Effects Of Geosynthetic Reinforcement On Performance Of Ballasted Rail Track, Pongpipat Anantanasakul, Buddhima Indraratna, Sanjay S. Nimbalkar, Tim Neville

Faculty of Engineering and Information Sciences - Papers: Part A

The 'field' performance of different geosynthetics to reinforce ballasted rail tracks was investigated. An extensive monitoring program was undertaken on fully instrumented track sections constructed near Singleton, New South Wales. Four types of geosynthetics were installed at the ballast-subballast interface of track sections located on subgrades with three distinctly different values of stiffness. It was found that geogrids could decrease vertical settlements of the ballast layer with obvious benefits of improved track stability and decreased maintenance cost. It was also found that the effectiveness of reinforcing geogrids increased when the subgrade stiffness decreased. Keywords: Geosynthetic, Reinforcement, Rail track, Ballast.

Multi-Objective Reactive Power Support From Wind Farms For Network Performance Enhancement, Lasantha Meegahapola, Brendan Fox, Tim Littler, Damian Flynn

Faculty of Engineering and Information Sciences - Papers: Part A

This paper examines the ability of the doubly fed induction generator (DFIG) to deliver multiple reactive power objectives during variable wind conditions. The reactive power requirement is decomposed based on various control objectives (e.g. power factor control, voltage control, loss minimisation, and flicker mitigation) defined around different time frames (i.e. seconds, minutes, and hourly), and the control reference is generated by aggregating the individual reactive power requirement for each control strategy. A novel coordinated controller is implemented for the rotor-side converter and the grid-side converter considering their capability curves and illustrating that it can effectively utilise the aggregated DFIG reactive …

Enhanced Rate Performance Of Cobalt Oxide/Nitrogen Doped Graphene Composite For Lithium Ion Batteries, Dan Li, Dongqi Shi, Zhixin Chen, Hua-Kun Liu, Dianzeng Jia, Zaiping Guo

Faculty of Engineering and Information Sciences - Papers: Part A

Ultrafine Co3O4 nanocrystals homogeneously attached to nitrogen doped reduced graphene oxide (rGO) by the hydrothermal reaction method are demonstrated as anode materials for lithium ion batteries. Transmission electron microscope images revealed that the crystal size of Co3O4 in Co3O4/N-rGO and Co3O4/rGO is 5-10 nm, much smaller than that of bare Co3O4, indicating that the reduced graphene oxide sheets with Co3O4 nanocrystals attached could hinder the growth and aggregation of Co3O4 crystals during synthesis. The graphene sheets can also effectively buffer the volume change of Co3O4 upon lithium insertion/extraction, thus improving the cycling performance of the composite electrodes. The doped nitrogen …

A High Performance Peer To Cloud And Peer Model Augmented With Hierarchical Secure Communications, Zhe Sun, Jun Shen

Faculty of Engineering and Information Sciences - Papers: Part A

This paper presents a secure storage model named Peer to Cloud and Peer (P2CP). P2CP uses the cloud storage system as a backbone storage system. However, when data transmission occurs, the data nodes, cloud user, and the non-cloud user are involved to complete the transaction all together. The users, typically the client peers, can communicate with each other directly, thus bypassing servers on the cloud. Similarly, cloud servers can communicate with each other in a P2P mode. We also introduce a "hierarchy security" method to guarantee the data security in the proposed P2CP storage model. A key feature of our …

Smart Multifunctional Fluids For Lithium Ion Batteries: Enhanced Rate Performance And Intrinsic Mechanical Protection, Jie Ding, Tongfei Tian, Qing Meng, Zaiping Guo, Weihua Li, Peng Zhang, Fabio T. Ciacchi, Jewel Huang, Wenrong Yang

Faculty of Engineering and Information Sciences - Papers: Part A

Lithium ion batteries are attractive power sources for the consumer electronics market and are being aggressively developed for road transportation. Nevertheless, issues with safety and reliability need to be solved prior to the large-scale uptake of these batteries. There have recently been significant development and assessment of materials with resistance to mechanical abuse, with the aims of reinforcing the battery and preventing puncturing during a crash. Most of the work on battery mechanical safety has concentrated on the external packaging of batteries, with little attention being paid to the enclosed electrolyte. We report on smart multifunctional fluids that act as …

Teamwork As A Service: A Cloud-Based System For Enhancing Teamwork Performance In Mobile Learning, Geng Sun, Jun Shen

Faculty of Engineering and Information Sciences - Papers: Part A

Although cloud computing helps learners to access online learning content through commonly used devices, it can be difficult to collaborate in the mobile environment. We develop a service-oriented system, ‘Teamwork as a Service’ (TaaS), to facilitate learners’ team learning activities. The five main services of TaaS facilitate a teamwork-enhanced learning flow associated with the theory of Kolb’s team learning experience, providing learners with an introduction, a ‘jigsaw classroom’, schedule planning, and mutual supervision during the whole process. Specifically, TaaS enables a rational grouping mechanism that allocates learners to their appropriate tasks in order to give their best performance. TaaS is …

Facilitating Collaborative Learning In Taas: A Mobile Cloud System For Enhancing Teamwork Performance, Geng Sun, Jun Shen

Faculty of Engineering and Information Sciences - Papers: Part A

Mobile cloud-based learning is a novel trend that brings many advantages to distributed learners to achieve collaborative learning, but it still lacks of mechanisms to enhance their teamwork performances. To make up that shortcoming, combining the features of cloud environment, we have identified a learning flow, a specification of workflow, based on Kolb team learning experience. This novel learning flow can be executed by our newly designed system, Teamwork as a Service (TaaS), in conjunction with cloud-hosting learning management systems, following which learners benefit from functions given by cloudbased services, separately for organizing cloud jigsaw classroom, planning and publishing tasks, …

Impact Of Humic Acid Fouling On Membrane Performance And Transport Of Pharmaceutically Active Compounds In Forward Osmosis, Ming Xie, Long D. Nghiem, William E. Price, Menachem Elimelech

Faculty of Engineering and Information Sciences - Papers: Part A

The impact of humic acid fouling on the membrane transport of two pharmaceutically active compounds (PhACs) - namely carbamazepine and sulfamethoxazole - in forward osmosis (FO) was investigated. Deposition of humic acid onto the membrane surface was promoted by the complexation with calcium ions in the feed solution and the increase in ionic strength at the membrane surface due to the reverse transport of NaCl draw solute. The increase in the humic acid deposition on the membrane surface led to a substantial decrease in the membrane salt (NaCl) permeability coefficient but did not result in a significant decrease in the …

Performance Evaluation Of Cooperative Communications For Stfc Mb-Ofdm Uwb, Zixuan Lin, Le Chung Tran, Farzad Safaei

Faculty of Engineering and Information Sciences - Papers: Part A

Recently, the combination of cooperative communication, Space-Time-Frequency Codes (STFCs) and Multiband OFDM Ultra-Wideband (MB-OFDM UWB) has been proposed to improve the data rate, system capacity and reliability. This paper provides insightful performance evaluation for our previous proposed cooperative communication schemes for MBOFDM UWB systems. In particular, this paper shows that the usefulness of cooperative communication schemes is decided by the mutual relation between the signal-to-noise ratio (SNR) of the inter-node links, referred to as inter-node SNR, and that of the uplinks, which is referred to as uplink SNR. For a certain uplink SNR value, cooperative communication becomes useful when the …

Performance Evaluation Of Bioethanol Production Through Continuous Fermentation With A Settling Unit, Mark I. Nelson, Norhayati Hamzah

Faculty of Engineering and Information Sciences - Papers: Part A

This paper analyses a model for the production of bioethanol that has been calibrated against laboratory data by previous researchers. The authors investigate the improvement in productivity that can be obtained when a centrifuge is used to recycle cells that would otherwise leave the reactor system in the efficient stream. The authors compare the performance of a double reactor cascade, possible employing a settling unit, against that of a single reactor. For the former case, this paper considers the reactor configuration in which the settling unit recycles from the effluent stream of a reactor back in the influent of the …

Performance And Prediction Of Marine Clay Treated With Vacuum And Surcharge Consolidation At Port Of Brisbane, Buddhima Indraratna, A S. Balasubramaniam, Harry Poulos, Cholachat Rujikiatkamjorn, Jayantha Ameratunga

Faculty of Engineering and Information Sciences - Papers: Part A

During the past decade, the application of vacuum preloading for stabilising soft coastal clay and other low-lying estuarine soils has become popular in Australia. The cost-effectiveness isa major factor in most projects in view of the significantly reduced time for achieving high degree of consolidation. Due to an increase in trade activities at the Port of Brisbane, new facilities on Fisherman Islands at the mouth of the Brisbane River will be constructed on the new outer area (235 ha) adjacent to the existing port facilities via land reclamation. A vacuum assited surcharge load and conventional surcharge scheme in conjunction with …

Tuning Performance Of E-Business Applications Through Automatic Transformation Of Persistent Database Structures, Janusz R. Getta

Faculty of Engineering and Information Sciences - Papers: Part A

Performance of e-business applications strongly depends on internal implementations of persistent database structures and on effective algorithms processing these structures. Commercial database systems, which are the basis of e-business applications typically implement logical database structures with one-size-fits-all persistent storage structure. This work investigates a new class of database systems where a conceptual and logical view of a database can be implemented in many different ways depending on the performance requirements of database applications. We consider the improvements to performance of e-business applications through automatic changes of the persistent database structures in the ways indicated by the performance statistics obtained from …

Performance Of Cfrp Wrapped Square Reinforced Concrete Columns Subjected To Eccentric Loading, Ida Bagus Rai Widiarsa, Muhammad N. S Hadi

Faculty of Engineering and Information Sciences - Papers: Part A

Strengthening concrete columns with fibre-reinforced polymers (FRP) has been studied extensively, but the majority of published studies have focused on circular columns. Most concrete columns in the field have square or rectangular cross sections and resist eccentric loading as well. The objective of this study is to investigate the performance of square reinforced concrete (RC) columns wrapped with carbon FRP subjected to eccentric loading. The influence of two parameters was studied including the number of FRP layers and the magnitude of eccentricity. Compression testing was conducted on twelve short square RC columns wrapped with CFRP composites. The columns had a …

A Forward Osmosis-Membrane Distillation Hybrid Process For Direct Sewer Mining: System Performance And Limitations, Ming Xie, Long D. Nghiem, William E. Price, Menachem Elimelech

Faculty of Engineering and Information Sciences - Papers: Part A

This study demonstrates the robustness and treatment capacity of a forward osmosis (FO)-membrane distillation (MD) hybrid system for small-scale decentralized sewer mining. A stable water flux was realized using a laboratory-scale FO-MD hybrid system operating continuously with raw sewage as the feed at water recovery up to 80%. The hybrid system also showed an excellent capacity for the removal of trace organic contaminants (TrOCs), with removal rates ranging from 91 to 98%. The results suggest that TrOC transport through the FO membrane is governed by "solute-membrane" interaction, whereas that through the MD membrane is strongly correlated to TrOC volatility. Concentrations …

Performance Monitoring Of Rail Tracks Stabilized By Geosynthetics And Shock Mats: Case Studies At Bulli And Singleton In Australia, Buddhima Indraratna, Sanjay Nimbalkar, Pongpipat Anantanasakul, Cholachat Rujikiatkamjorn, Tim Neville

Faculty of Engineering and Information Sciences - Papers: Part A

Rail tracks are conventionally built on compacted ballast and structural fill embankments overlying the natural subsoil. Ballast plays an important role in providing track stiffness to support heavy traffic loads, and providing rapid drainage. However, ballast deforms and degrades progressively under the heavy cyclic loading of passenger and freight trains, which may lead to a loss of track geometry, and require costly regular maintenance. In particular, track construction requires appropriate stabilization techniques for ballast, the extent of which depends also on the type of subgrade. Comprehensive field trials were carried out on two rail lines in Bulli and recently in …

Cation Exchange At Semiconducting Oxide Surfaces: Origin Of Light-Induced Performance Increases In Porphyrin Dye-Sensitized Solar Cells, Matthew J. Griffith, Kenji Sunahara, Akihiro Furube, Attila J. Mozer, David L. Officer, Pawel Wagner, Gordon G. Wallace, Shogo Mori

Australian Institute for Innovative Materials - Papers

The origin of simultaneous improvements in the short-circuit current density (Jsc) and open-circuit voltage (Voc) of porphyrin dye-sensitized TiO2 solar cells following white light illumination was studied by systematic variation of several different device parameters. Reduction of the dye surface loading resulted in greater relative performance enhancements, suggesting open space at the TiO2 surface expedites the process. Variation of the electrolyte composition and subsequent analysis of the conduction band potential shifts suggested that a light-induced replacement of surface-adsorbed lithium (Li+) ions with dimethylpropylimidazolium (DMPIm+) ions was responsible for an increased electron lifetime by decreasing the recombination with the redox mediator. …

Aqueous Dispersions Of Reduced Graphene Oxide And Multi Wall Carbon Nanotubes For Enhanced Glucose Oxidase Bioelectrode Performance, Willo Grosse, Joffrey Champavert, Sanjeev Gambhir, Gordon G. Wallace, Simon E. Moulton

Australian Institute for Innovative Materials - Papers

Aqueous dispersions of reduced graphene oxide (rGO) and multi walled carbon nanotubes (MWCNT) were fabricated through a modified chemical reduction method. The significant advantage of the method developed here is the omission of any stabilising compound or organic solvent to obtain stable rGO-MWCNT dispersions. Significantly biological entities, in this case the enzyme glucose oxidase (GOx), can be successfully incorporated into the dispersion. These dispersions were characterised using XPS, SEM, zeta potential and particle size measurements which showed that the dispersion stability is not sacrificed with the addition of GOx, and significantly, the electrical properties of the rGO and MWCNTs are …

Evaluation Of Encapsulating Coatings On The Performance Of Polypyrrole Actuators, Sina Naficy, Nicholas Stoboi, Philip G. Whitten, Geoffrey M. Spinks, Gordon G. Wallace

Australian Institute for Innovative Materials - Papers

Conjugated polymer actuators are electroactive materials capable of generating force and movement in response to an applied external voltage. Many potential biomedical and industrial applications require these actuators to operate in a liquid environment. However, immersion of uncoated conducting polymer actuators in non-electrolyte liquids greatly reduces their operating lifetime. Here, we demonstrate the use of spray coating as an effective and simple method to encapsulate polypyrrole (PPy) tri-layer bending actuators. Poly(styrene-b-isobutylene-b-styrene) (SIBS) was used as an encapsulating, compliant spray coating on PPy actuators. A significant enhancement in actuator lifetime in both air and water was observed by encapsulating the actuators. …

Highly Uniform Tio2/Sno2/Carbon Hybrid Nanofibers With Greatly Enhanced Lithium Storage Performance, Zunxian Yang, Qing Meng, Zaiping Guo, Xuebin Yu, Tailiang Guo, Rong Zeng

Australian Institute for Innovative Materials - Papers

Highly uniform, relatively large area TiO2/SnO 2/carbon hybrid nanofibers were synthesized by a simple method based on thermal pyrolysis and oxidation of an as-spun titanium-tin/polyacrylonitrile nanoweb composite in an argon atmosphere. This novel composite features the uniform dispersion and encapsulation of highly uniform nanoscale TiO 2/SnO2 crystals in a porous carbon matrix. The high porosity of the nanofiber composite material, together with the conductive carbon matrix, enhanced the electrochemical performance of the TiO 2/SnO2/carbon nanofiber electrode. The TiO 2/SnO2/carbon nanofiber electrode displays a reversible capacity of 442.8 mA h g-1 for up to 100 cycles, and exhibits excellent rate capability. …

Safety Performance Evaluation Of The Non-Blocked Midwest Guardrail System, Kevin D Schrum, Karla A. Lechtenberg, Robert W. Bielenberg, Scott K. Rosenbaugh, Ronald K. Faller, John D. Reid

Nebraska Department of Transportation: Research Reports

No abstract provided.

Product Lifecycle Management: Measuring What Is Important - Product Lifecycle Implementation Maturity Model, Abram Walton, Cynthia Tomovic, Michael Grieves

STEMPS Faculty Publications

Industry reports that benefits of PLM are difficult to assess because the same benefit can be expressed as a function of time, cost, quality, or any combination. Based on a review of the PLM literature in an earlier study, a PLM Process Model and an initial list of PLM related metrics was generated and later confirmed through interviews with experienced PLM users. In the current study, the original PLM Process Model was refined and the list of metrics was subjected to an exploratory factor analysis in which specific metrics were found to be related to one of four factors: Inputs, …