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Full-Text Articles in Social and Behavioral Sciences
A Random Effect Block Bootstrap For Clustered Data, Raymond L. Chambers, Hukum Chandra
A Random Effect Block Bootstrap For Clustered Data, Raymond L. Chambers, Hukum Chandra
Faculty of Engineering and Information Sciences - Papers: Part A
Random effects models for hierarchically dependent data, e.g. clustered data, are widely used. A popular bootstrap method for such data is the parametric bootstrap based on the same random effects model as that used in inference. However, it is hard to justify this type of bootstrap when this model is known to be an approximation. In this paper we describe a random effect block bootstrap approach for clustered data that is simple to implement, free of both the distribution and the dependence assumptions of the parametric bootstrap and is consistent when the mixed model assumptions are valid. Results based on …
The Effect Of Cooling Rates On The Microstructure And Mechanical Properties Of Thermo-Mechanically Processed Ti-Al-Mo-V-Cr-Fe Alloys, Mansur Ahmed, Dmytro G. Savvakin, Orest M. Ivasishin, Elena V. Pereloma
The Effect Of Cooling Rates On The Microstructure And Mechanical Properties Of Thermo-Mechanically Processed Ti-Al-Mo-V-Cr-Fe Alloys, Mansur Ahmed, Dmytro G. Savvakin, Orest M. Ivasishin, Elena V. Pereloma
Faculty of Engineering and Information Sciences - Papers: Part A
Two near-β titanium alloys, Ti–5Al–5Mo–5V–1Cr–1Fe and a modified one containing 2 wt% Cr (Ti–5Al–5Mo–5V–2Cr–1Fe) were produced from Ti hydride precursor powders via the cost-effective blended elemental powder metallurgy technique. The effects of two cooling rates (10 K s−1 and 1 K s−1) during thermo-mechanical processing on the microstructure and mechanical properties were investigated using X-ray diffraction and scanning electron microscopy. X-ray line profile analysis revealed that dislocation densities and microstrain in β-Ti phase are higher than in α-Ti phase for all cases. In both alloys, slower cooling results in an increase in α volume fraction and promotes morphology of continuous …
Effect Of Deformation Temperature On Niobium Clustering, Precipitation And Austenite Recrystallisation In A Nb-Ti Microalloyed Steel, Andrii G. Kostryzhev, Abdullah Al Alshahrani, Chen Zhu, Simon P. Ringer, Elena V. Pereloma
Effect Of Deformation Temperature On Niobium Clustering, Precipitation And Austenite Recrystallisation In A Nb-Ti Microalloyed Steel, Andrii G. Kostryzhev, Abdullah Al Alshahrani, Chen Zhu, Simon P. Ringer, Elena V. Pereloma
Faculty of Engineering and Information Sciences - Papers: Part A
The effect of deformation temperature on Nb solute clustering, precipitation and the kinetics of austenite recrystallisation were studied in a steel containing 0.081C–0.021Ti–0.064 Nb (wt%). Thermo-mechanical processing was carried out using a Gleeble 3500 simulator. The austenite microstructure was studied using a combination of optical microscopy, transmission electron microscopy, and atom probe microscopy, enabling a careful characterisation of grain size, as well as Nb-rich clustering and precipitation processes. A correlation between the austenite recrystallisation kinetics and the chemistry, size and number density of Nb-rich solute atom clusters, and NbTi(C,N) precipitates was established via the austenite deformation temperature. Specifically, we have …
Effect Of Austenitising And Deformation Temperatures On Dynamic Recrystallisation In Nb-Ti Microalloyed Steel, Andrii G. Kostryzhev, Abdullah Al Shahrani, Chen Zhu, Simon P. Ringer, Elena V. Pereloma
Effect Of Austenitising And Deformation Temperatures On Dynamic Recrystallisation In Nb-Ti Microalloyed Steel, Andrii G. Kostryzhev, Abdullah Al Shahrani, Chen Zhu, Simon P. Ringer, Elena V. Pereloma
Faculty of Engineering and Information Sciences - Papers: Part A
An investigation into influence of the austenitising temperature and the austenite deformation temperature on Nb precipitation and recrystallisation kinetics was carried out for a steel containing 0.081C-0.021Ti-0.064Nb (wt. %). The austenite grain structure was correlated to the dispersive properties of Nb atom clustering and precipitation. Irrespective of the austenitising temperature, deformation to 0.75 strain at 1075 °C produced a fully recrystallised microstructure. After deformation at 975 °C, only partial recrystallisation was observed in the samples austenitised at higher temperature, whereas samples austenitised at lower temperature were fully recrystallised. The influence of solute drag and particle pinning effects on the recrystallisation …
Effect Of First Network Topology On The Toughness Of Double Network Hydrogels, Hai Xin, Sureyya Saricilar, Hugh Ralph Brown, Philip G. Whitten, Geoffrey Maxwell Spinks
Effect Of First Network Topology On The Toughness Of Double Network Hydrogels, Hai Xin, Sureyya Saricilar, Hugh Ralph Brown, Philip G. Whitten, Geoffrey Maxwell Spinks
Faculty of Engineering and Information Sciences - Papers: Part A
The fracture toughness of a double network (DN) hydrogel is shown here to be directly proportional to the toughness of the first-formed network. A series of DN gels was prepared in which the cross-link density of the first (tighter) network was controlled by varying the monomer and cross-linker concentrations. The toughness, tensile strength and elastic modulus of the DN gels increased significantly with an increase in the cross-link density of the first network and with identically prepared second networks. Moreover, the toughness of the double network was found to be linearly related to the toughness of the first network with …
Effect Of Particle Properties On The Discrete Element Simulation Of Wall Friction, Andrew Grima, Peter Wypych
Effect Of Particle Properties On The Discrete Element Simulation Of Wall Friction, Andrew Grima, Peter Wypych
Faculty of Engineering and Information Sciences - Papers: Part A
Modelling the interaction between particles and boundaries is of great interest and importance in many Discrete Element Method (DEM) applications where boundary failure conditions dictate the flow behaviour and velocity gradients of a bulk material. Bulk wall friction angles in DEM models are dependent on the mechanical properties of the particles and boundary material as well as the constraints of the contact models used, especially the tangential and rolling torque components. This paper examines the parameters determined from the calibration inclination test by conducting direct wall shear tests to validate the accuracy of the calibration parameters and the sensitivity of …
The Effect Of Chemical Composition On Microstructure And Properties Of Intercritically Reheated Coarse-Grained Heat-Affected Zone In X70 Steels, Zhixiong Zhu, Lenka Kuzmikova, Huijun Li, Frank J. Barbaro
The Effect Of Chemical Composition On Microstructure And Properties Of Intercritically Reheated Coarse-Grained Heat-Affected Zone In X70 Steels, Zhixiong Zhu, Lenka Kuzmikova, Huijun Li, Frank J. Barbaro
Faculty of Engineering and Information Sciences - Papers: Part A
The current study investigates the effect of different levels of Ti, N, and Ti/N ratios on microstructure and properties in the intercritically reheated coarse-grained heat-affected zone (ICCGHAZ) of two-pass submerged arc welds in API 5L grade X70 pipe. Gleeble simulation was employed to reproduce the ICCGHAZ of actual welds. Hardness and Charpy V-notch (CVN) tests were performed on the simulated samples. The microstructure of simulated ICCGHAZ was characterized by optical microscopy and scanning electron microscopy (SEM). LePera color etching technique was employed to identify and quantify the martensitic-austenitic (M-A) constituent. Results show that the simulated ICCGHAZ exhibited extremely low toughness, …
The Joint Effect Of Image Blur And Illumination Distortions For Mobile Visual Search Of Print Media, Yi Cao, Christian Ritz, Raad Raad
The Joint Effect Of Image Blur And Illumination Distortions For Mobile Visual Search Of Print Media, Yi Cao, Christian Ritz, Raad Raad
Faculty of Engineering and Information Sciences - Papers: Part A
Mobile Visual Search (MVS) is an emerging area of research given the explosion of smart and powerful mobile devices. Typically, the performance of MVS applications is influenced by the implemented image processing algorithms as well as various distortions that occur when capturing images by the mobile camera. This paper examines the joint effect of two common distortions, namely the illumination changes and image blurring on image matching accuracy for print media when using four state-of-the art local feature algorithms. Results obtained for a database of real camera images captured by two different camera models show that the illumination changes have …
Automatic Bdi Plan Recognition From Process Execution Logs And Effect Logs, Hongyun Xu, Bastin Tony Roy Savarimuthu, Aditya Ghose, Evan Morrison, Qiying Cao, Youqun Shi
Automatic Bdi Plan Recognition From Process Execution Logs And Effect Logs, Hongyun Xu, Bastin Tony Roy Savarimuthu, Aditya Ghose, Evan Morrison, Qiying Cao, Youqun Shi
Faculty of Engineering and Information Sciences - Papers: Part A
Agent applications are often viewed as unduly expensive to develop and maintain in commercial contexts. Organizations often settle for less sophisticated and more traditional software in place of agent technology because of (often misplaced) fears about the development and maintenance costs of agent technology, and the often mistaken perception that traditional software offers better returns on investment. This paper aims to redress this by developing a plan recognition framework for agent program learning, where behavior logs of legacy applications (or even manually executed processes) are mined to extract a 'draft' version of agent code that could eventually replace these applications …
Effect Of Rice Husk Ash On Workability And Strength Of Concrete, Avinash Babu Srinivasreddy, Timothy J. Mccarthy, Eric Lume
Effect Of Rice Husk Ash On Workability And Strength Of Concrete, Avinash Babu Srinivasreddy, Timothy J. Mccarthy, Eric Lume
Faculty of Engineering and Information Sciences - Papers: Part A
Rice husk ash (RHA) is an agricultural waste which is a pozzolanic material that can be blended with the cement for manufacturing concrete. Its use can reduce the environmental impact of the cement industry. The present study investigates the chemical and morphological nature of RHA and silica fume (SF). Both can be used to improve strength and durability properties of concrete. Particle size distribution, loss on ignition (LOI), X-ray diffraction analysis, scanning electron microscopic were conducted. The effect of replacement of cement 5%, 10% and 15% by weight with SF and RHA on compressive strength and workability has also been …
Effect Of Confining Pressure And Frequency On The Deformation Of Ballast, Pramod Kumar Thakur, Jayan Sylaja Vinod, Buddhima Indraratna
Effect Of Confining Pressure And Frequency On The Deformation Of Ballast, Pramod Kumar Thakur, Jayan Sylaja Vinod, Buddhima Indraratna
Faculty of Engineering and Information Sciences - Papers: Part A
Increasing the speed and frequency of trains with the same static axle weight imparts higher dynamic axle loads more frequently. When this occurs on existing track which has not been designed for such loading there can be increased rates of ballast degradation, characterised by unacceptable deformation and lateral spread, leading to more frequent requirements for track maintenance. Recent studies carried out at the University of Wollongong highlighted that confining pressure and frequency have a significant influence on the permanent deformation and degradation of ballast. However, confinement required to keep the deformation and degradation of the ballasted track to an acceptable …
Effect Of Cooling Rate On Oxidation Behaviour Of Microalloyed Steel, Xianglong Yu, Zhengyi Jiang, Jingwei Zhao, Dongbin Wei, Cunlong Zhou
Effect Of Cooling Rate On Oxidation Behaviour Of Microalloyed Steel, Xianglong Yu, Zhengyi Jiang, Jingwei Zhao, Dongbin Wei, Cunlong Zhou
Faculty of Engineering and Information Sciences - Papers: Part A
Oxidation characteristics of a microalloyed low carbon steel were investigated by a hot rolling mill combined with acceleration cooling system over the cooling rate range from 20 to 70°C/s. The effects of cooling rate after hot rolling on microstructure and phase composition of oxide scale were examined. The results showed that the increase of the cooling rate has a significant influence on the decrease of the grain size and surface roughness of oxide scale. A higher cooling rate promotes the formation of retain wustite and primary magnetite precipitation while suppression of eutectoid α-iron precipitates. This provides the possibility to enhance …
The Effect Of Slag Basicity On Spinal Inclusion Wettability, Hamed Abdeyazdan, Brian J. Monaghan, Neslihan Dogan, M Akbar Rhamdhani
The Effect Of Slag Basicity On Spinal Inclusion Wettability, Hamed Abdeyazdan, Brian J. Monaghan, Neslihan Dogan, M Akbar Rhamdhani
Faculty of Engineering and Information Sciences - Papers: Part A
Steel cleanness is an important and growing research area driven by the demands to produce high quality steel. Inclusion content in steel is an important criterion to assess clean steel. MgO.Ah03 spinel inclusions cause problems in steel processing and are generally deleterious to steel products due to their high melting point and high hardness. Jnclusions are generally r· moved by rea ting with slag. This is primarily achieved by optimizing lhe PI' 'ess omliLions to promote contact and reaction between the inclusion and S,l,lg '. or efticient rem val from the steel the inclusions must attach to and dissolve in …
Confinement Effect Of Frp And Transverse Steel On Retrofitting Square Concrete Columns, Le V. Doan, Xu Lei, Muhammad N. S Hadi, Thong M. Pham
Confinement Effect Of Frp And Transverse Steel On Retrofitting Square Concrete Columns, Le V. Doan, Xu Lei, Muhammad N. S Hadi, Thong M. Pham
Faculty of Engineering and Information Sciences - Papers: Part A
This study presents an experimental investigation into strain distribution of Fibre-Reinforced Polymer (FRP) in FRP-confined concrete columns with internal steel reinforcement under concentric and eccentric loading conditions. A total of nine reinforced concrete columns were cast and tested. Three of them were square in cross-section while the others were originally square but were shape-modified into circular columns with four pieces of segmental circular concrete covers and confined with three layers of CFRP. The nominal compressive strength of the segmental concrete covers was 40 MPa and 80 MPa. All columns were tested under concentric load, 25 mm or 50 mm eccentric …
Long-Distance Walking Effect On Below-Knee Amputee Compensatory Gait Patterns And Implications On Prosthetic Designs And Training, L F. Yeung, Aaron Leung, Ming Zhang, Winson Lee
Long-Distance Walking Effect On Below-Knee Amputee Compensatory Gait Patterns And Implications On Prosthetic Designs And Training, L F. Yeung, Aaron Leung, Ming Zhang, Winson Lee
Faculty of Engineering and Information Sciences - Papers: Part A
Trans-tibial amputees are advised to walk as much as able people to achieve healthy and independent life. However, they usually have difficulties in doing so. Previous researches only included data from a few steps when studying the gait of amputees. Walking over a long distance was rarely examined. The objective of this study was to investigate the changes in spatial-temporal, kinetic and kinematic gait parameters of trans-tibial amputees after long-distance walking. Six male unilateral trans-tibial amputees performed two sessions of 30-min walking on a level treadmill at their self-selected comfortable speed. Gait analysis was undertaken over-ground: (1) before walking, (2) …
Semi-Analytical Solutions For Cubic Autocatalytic Reaction-Diffusion Equations; The Effect Of A Precursor Chemical, Muteb Alharthi, Timothy Marchant, Mark Nelson
Semi-Analytical Solutions For Cubic Autocatalytic Reaction-Diffusion Equations; The Effect Of A Precursor Chemical, Muteb Alharthi, Timothy Marchant, Mark Nelson
Faculty of Engineering and Information Sciences - Papers: Part A
Semi-analytical solutions for a cubic autocatalytic reaction, with linear decay and a precursor chemical, are considered. The model is coupled with diffusion and considered in a one-dimensional reactor. In this model the reactant is supplied by two mechanisms, diffusion via the cell boundaries and decay of an abundant precursor chemical present in the reactor. The Galerkin method is used to approximate the spatial structure of the reactant and autocatalyst concentrations in the reactor. Ordinary differential equations are then obtained as an approximation to the governing partial differential equations and analyzed to obtain semi-analytical results for the reaction-diffusion cell. Singularity theory …
Effect Of The Austenitising Heat Treatment On The Microstructure And Hardness Of Martensitic Stainless Steel Aisi 420, Lilian D. Barlow, Madeleine Du Toit
Effect Of The Austenitising Heat Treatment On The Microstructure And Hardness Of Martensitic Stainless Steel Aisi 420, Lilian D. Barlow, Madeleine Du Toit
Faculty of Engineering and Information Sciences - Papers: Part A
The effect of austenitizing on the microstructure and hardness of two martensitic stainless steels was examined with the aim of supplying heat-treatment guidelines to the user that will ensure a martensitic structure with minimal retained austenite, evenly dispersed carbides and a hardness of between 610 and 740 HV (Vickers hardness) after quenching and tempering. The steels examined during the course of this examination conform in composition to medium-carbon AISI 420 martensitic stainless steel, except for the addition of 0.13% vanadium and 0.62% molybdenum to one of the alloys. Steel samples were austenitized at temperatures between 1000 and 1200 C, followed …
Effect Of Gallium Doping And Ball Milling Process On The Thermoelectric Performance Of N-Type Zno, Priyanka Jood, Germanas Peleckis, Xiaolin Wang, S X. Dou
Effect Of Gallium Doping And Ball Milling Process On The Thermoelectric Performance Of N-Type Zno, Priyanka Jood, Germanas Peleckis, Xiaolin Wang, S X. Dou
Faculty of Engineering and Information Sciences - Papers: Part A
We report a systematic investigation of the thermoelectric properties of n-type Ga-doped ZnO synthesized using different ball milling conditions. Samples fabricated by the high-energy ball milling resulted in a highly dense layered structure with randomly distributed voids. These samples measured the lowest room temperature thermal conductivity, i.e., 27 W/mK due to increased phonon scattering. Furthermore, the Ga:ZnO system showed a metal–semiconductor transition above 300 K with transition temperature decreasing with increasing doping level. Measurement of the activation energy revealed the presence of one donor level around 3.9–7.8 meV and a deeper donor level around 15.4–18.1 meV below the conduction band …
The Effect Of Incomplete Mixing Upon The Belousov-Zhabotinskii Reaction, Ahmed Hussein Msmali, Mark I. Nelson, Maureen P. Edwards
The Effect Of Incomplete Mixing Upon The Belousov-Zhabotinskii Reaction, Ahmed Hussein Msmali, Mark I. Nelson, Maureen P. Edwards
Faculty of Engineering and Information Sciences - Papers: Part A
The aim of this research to investigate the effect of incomplete mixing upon the existence of periodic solutions. To this end we study the behaviour of the Belousov- Zhabotinskii (B-Z) reaction in a batch reactor. The B-Z reaction is a well studied chemical system that exhibits periodic behaviour. Furthermore, simplified mathematical models exist which have been validated both against experimental data and larger chemical mechanisms. Specifically, we study the `Oregonator' model for the B-Z reaction due to Field and Noyes (1974). This consists of five chemical reactions involving three independent chemical intermediates. We extend this model by combining it with …
On The Dosimetric Effect And Reduction Of Inverse Consistency And Transitivity Errors In Deformable Image Registration For Dose Accumulation, Edward T. Bender, Nicholas Hardcastle, Wolfgang A. Tome
On The Dosimetric Effect And Reduction Of Inverse Consistency And Transitivity Errors In Deformable Image Registration For Dose Accumulation, Edward T. Bender, Nicholas Hardcastle, Wolfgang A. Tome
Faculty of Engineering and Information Sciences - Papers: Part A
Purpose: Deformable image registration (DIR) is necessary for accurate dose accumulation between multiple radiotherapy image sets. DIR algorithms can suffer from inverse and transitivity inconsistencies. When using deformation vector fields (DVFs) that exhibit inverse-inconsistency and are nontransitive, dose accumulation on a given image set via different image pathways will lead to different accumulated doses. The purpose of this study was to investigate the dosimetric effect of and propose a postprocessing solution to reduce inverse consistency and transitivity errors. Methods: Four MVCT images and four phases of a lung 4DCT, each with an associated calculated dose, were selected for analysis. DVFs …
Terahertz Photon Mixing Effect In Graphene And Topological Insulator, Yee Sin Ang, Qinjun Chen, Xiaolin Wang, R A. Lewis, Chao Zhang
Terahertz Photon Mixing Effect In Graphene And Topological Insulator, Yee Sin Ang, Qinjun Chen, Xiaolin Wang, R A. Lewis, Chao Zhang
Faculty of Engineering and Information Sciences - Papers: Part A
We theoretically investigate the nonlinear terahertz photon-mixing effect in graphene and topological insulator. We show that the nonlinear intraband optical absorption in both materials dominate over the linear response under a very moderate external electric field strength. The nonlinear response is thermally enhanced and the optical nonlinearity is well-preserved even in high temperature regime.
Effect Of Manganese Content And Microstructure On The Susceptibility Of X70 Pipeline Steel To Hydrogen Cracking, D Hejazi, A J. Haq, N Yazdipour, D P. Dunne, A Calka, Frank J. Barbaro, E V. Pereloma
Effect Of Manganese Content And Microstructure On The Susceptibility Of X70 Pipeline Steel To Hydrogen Cracking, D Hejazi, A J. Haq, N Yazdipour, D P. Dunne, A Calka, Frank J. Barbaro, E V. Pereloma
Faculty of Engineering and Information Sciences - Papers: Part A
The influence of composition and microstructure on susceptibility to hydrogen induced cracking (HIC) was investigated in high strength pipeline steels, with Mn contents of 1.2% (standard, X70), and 0.5% (medium, MX70). The HIC resistance of the simulated coarse grained heat affected zone microstructures and normalized X70 transfer bar was also investigated. Notched and fatigue pre-cracked samples were charged with hydrogen prior to three point bend tests. The conditional fracture toughness JQ was determined. The results are discussed in relation to grain size, microstructure, composition and the type and distribution of non-metallic inclusions and precipitates.
Effect Of Coiling Temperature On Oxide Scale Of Hot-Rolled Strip, Xianglong Yu, Zhengyi Jiang, Xiaodong Wang, Dongbin Wei, Quan Yang
Effect Of Coiling Temperature On Oxide Scale Of Hot-Rolled Strip, Xianglong Yu, Zhengyi Jiang, Xiaodong Wang, Dongbin Wei, Quan Yang
Faculty of Engineering and Information Sciences - Papers: Part A
The influence of the coiling temperature, ranging from 550 to 570℃, on the morphology and the phase composition of the oxide scale formed on the microalloyed low carbon steel for automobiles after hot strip rolling was investigated. Physicochemical characteristics of the oxide scales were examined and their formation mechanism was discussed. Thickness of the oxide scale is in the range of 8-11μm and decreases with a decrease of coiling temperature. The microstructure and phase composition, XRD analysis shows a large amount of magnetite (Fe3O4) and some sparse hematite (Fe2O3) exist on the surface of hot rolled strip when the coiling …
The Effect Of Chromium Addition On The Strain Ageing And Recrystallisation Behaviour Of Low Carbon Steel, Elena Pereloma, V Bata, Azdiar A. Gazder
The Effect Of Chromium Addition On The Strain Ageing And Recrystallisation Behaviour Of Low Carbon Steel, Elena Pereloma, V Bata, Azdiar A. Gazder
Faculty of Engineering and Information Sciences - Papers: Part A
The strain ageing and recrystallisation behaviour of conventional low carbon A06 steel was compared with those containing varying amounts of chromium (0.26, 0.52 and 0.74 wt.%). The results show that the A06 steel undergoes four stages of strain ageing: (i) the pinning by solute atoms of dislocations generated during pre-strain, (ii) the generation of fresh dislocations from grain boundaries, (iii) the onset of precipitation and, (iv) the inhibition of dislocation generation from grain boundaries due to pinning by carbon segregation. On the other hand, the chromium containing steels only exhibit the fIrst three stages of strain ageing. An approximately twofold …
Rietveld Analysis Of The Effect Of Annealing Atmosphere On Phase Evolution Of Nanocrystalline Tio 2 Powders, M Salari, M Rezaee, A T. Chidembo, Konstantin Konstantinov, Hua-Kun Liu
Rietveld Analysis Of The Effect Of Annealing Atmosphere On Phase Evolution Of Nanocrystalline Tio 2 Powders, M Salari, M Rezaee, A T. Chidembo, Konstantin Konstantinov, Hua-Kun Liu
Faculty of Engineering and Information Sciences - Papers: Part A
The struclUral evolution of nanocrystaUine Ti02 was studied by X-ray diffraction (XRD) and the Rietveld refinement method (RRM). Ti02 powders were prepared by the sol-gel technique. Post annealing of as·synthesized powders in the temperature range from 500°C to 600 °C under air and argon atmospheres led to the formation of Ti02 nanoparticles with mean crystallite size in the range of 37-165 nm. based on the Rietveld refinement results. It was found that the phase structure, composition, and crystallite size of the resulting particles were dependent on not only the annealing temperature, but also the annealing atmosphere. Rietveld refinement of the …
Effect Of The Carbon Nanotube Surface Characteristics On The Conductivity And Dielectric Constant Of Carbon Nanotube/Poly(Vinylidene Fluoride) Composites, S A. Carabineiro, Manuel F. Pereira, J Nunes-Pereira, Cristina Caparrós, Vitor Sencadas, Senentxu Lanceros-Méndez
Effect Of The Carbon Nanotube Surface Characteristics On The Conductivity And Dielectric Constant Of Carbon Nanotube/Poly(Vinylidene Fluoride) Composites, S A. Carabineiro, Manuel F. Pereira, J Nunes-Pereira, Cristina Caparrós, Vitor Sencadas, Senentxu Lanceros-Méndez
Faculty of Engineering and Information Sciences - Papers: Part A
Commercial multi-walled carbon nanotubes (CNT) were functionalized by oxidation with HNO3, to introduce oxygen-containing surface groups, and by thermal treatments at different temperatures for their selective removal. The obtained samples were characterized by adsorption of N2 at -196°C, temperature-programmed desorption and determination of pH at the point of zero charge. CNT/poly(vinylidene fluoride) composites were prepared using the above CNT samples, with different filler fractions up to 1 wt%. It was found that oxidation reduced composite conductivity for a given concentration, shifted the percolation threshold to higher concentrations, and had no significant effect in the dielectric response.
Effect Of Magnetostatic Field On Microstructure Of 5005 Aluminum Alloy Sheet By Roll-Casting, Jintao Li, Guangming Xu, Jianzhong Cui
Effect Of Magnetostatic Field On Microstructure Of 5005 Aluminum Alloy Sheet By Roll-Casting, Jintao Li, Guangming Xu, Jianzhong Cui
Faculty of Engineering and Information Sciences - Papers: Part A
The roll-casting technology of 5000 series aluminum alloy is one of the difficulties at present. Roll-casting technology was employed in this paper and high quality 5005 aluminum alloy sheets were fabricated successfully under different conditions. The solidification of melt in roll-casting process is the rapid directional solidification. The effect of magnetostatic field on microstructure of 5005 aluminum alloy sheet by roll-casting has been investigated and analyzed. The results indicate that imposing magnetostatic field can refine the grains of 5005 aluminum alloy.
Bauschinger Effect In Microalloyed Steels: Part Ii. Influence Of Work Softening On Strength Development During Uoe Line-Pipe Forming, Andrii Kostryzhev, Martin Strangwood, Claire L. Davis
Bauschinger Effect In Microalloyed Steels: Part Ii. Influence Of Work Softening On Strength Development During Uoe Line-Pipe Forming, Andrii Kostryzhev, Martin Strangwood, Claire L. Davis
Faculty of Engineering and Information Sciences - Papers: Part A
The Bauschinger effect (a reduced yield stress at the start of reverse deformation following forward prestrain) is an important factor of strength development for cold metal forming technology. In steels, the magnitude of the Bauschinger effect depends on composition, through the presence of microalloy precipitates, and prior processing, through the size and distribution of the microalloy precipitates and the presence of retained work hardening. In this article, the parameters of the Bauschinger effect and work hardening (coefficient and exponent) in forward and reverse deformations were quantitatively related to the particle number density and dislocation density for two high-strength low-alloy (HSLA) …
Bauschinger Effect In Microalloyed Steels: Part I. Dependence On Dislocation-Particle Interaction, Andrii Kostryzhev, Martin Strangwood, Claire L. Davis
Bauschinger Effect In Microalloyed Steels: Part I. Dependence On Dislocation-Particle Interaction, Andrii Kostryzhev, Martin Strangwood, Claire L. Davis
Faculty of Engineering and Information Sciences - Papers: Part A
The Bauschinger effect (yield stress decreasing at the start of reverse deformation after forward prestrain) is an important factor in strength development for cold metal forming technology. In steels, the magnitude of the Bauschinger effect depends on composition, through the presence of microalloy precipitates, and prior processing, through the size and distribution of microalloy precipitates and presence of retained work hardening. In this article, the microstructures of two (Nb- and Nb-V-microalloyed) steel plates, in terms of (Ti,Nb,V,Cu)-rich particle distributions and dislocation densities, have been quantitatively related to the Bauschinger parameters for the same processing conditions. For the 12- to 50-nm …
A Critique Of The Marker Variable Technique: The Effect Of Alternative Marker Variable Criteria, Rajeev Sharma, Philip Yetton, Jeff Crawford
A Critique Of The Marker Variable Technique: The Effect Of Alternative Marker Variable Criteria, Rajeev Sharma, Philip Yetton, Jeff Crawford
Faculty of Engineering and Information Sciences - Papers: Part A
The marker variable technique offers a practical and easy method to address the validity threat on account of common method variance to the findings of individual studies. Hawever, the validity of the marker variable technique has not been established. This paper examines the validity threat to the marker variable technique arising from multiple criteria for the selection of the marker variable proposed in the literature. Our findings shaw that the conclusions that can be drawn under different criteria are significantly and substantially different, raising doubts about the validity of the marker variable technique. Proposals for developing theoretically grounded criteria for …