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Full-Text Articles in Social and Behavioral Sciences

Dynamic Response Analysis Of The Rotating Blade Of Horizontal Axis Wind Turbine, Xiong Liu, Xianmin Zhang, Gangqiang Li, Yan Chen, Zhiquan Ye Jan 2010

Dynamic Response Analysis Of The Rotating Blade Of Horizontal Axis Wind Turbine, Xiong Liu, Xianmin Zhang, Gangqiang Li, Yan Chen, Zhiquan Ye

Faculty of Engineering and Information Sciences - Papers: Part A

This paper presents a dynamic response analysis of the blade of horizontal axis wind turbines using finite element method. The blade is treated as a cantilever and modeled with two-node beam element. The blade element-momentum theory is applied to calculate the aerodynamic loads. Dynamic inflow and dynamic stall are taken into account to reflect the transient aerodynamics. The centrifugal stiffening is introduced to consider the restoring effects of centrifugal force. An aerodynamic damping model is presented for calculating the overall damping ratio instantaneously during time-domain simulation. The structural dynamic equation is solved using Newmark method and the overall dynamic response ...


High-Energy, Picosecond, Cryogenic Yb:Yag Chirped-Pulse Amplifier At Khz Repetition Rates For Opcpa Pumping, Kyung-Han Hong, Juliet Gopinath, Darren Rand, Aleem M. Siddiqui, Shu-Wei Huang, Enbang Li, Benjamin J. Eggleton, John D. Hybl, Tso Yee Fan, Franz X. Kartner Jan 2010

High-Energy, Picosecond, Cryogenic Yb:Yag Chirped-Pulse Amplifier At Khz Repetition Rates For Opcpa Pumping, Kyung-Han Hong, Juliet Gopinath, Darren Rand, Aleem M. Siddiqui, Shu-Wei Huang, Enbang Li, Benjamin J. Eggleton, John D. Hybl, Tso Yee Fan, Franz X. Kartner

Faculty of Engineering and Information Sciences - Papers: Part A

We report on the development of a 50-mJ-class ~10-ps chirped-pulse amplifier at kHz repetition rates using cryogenic Yb:YAG regenerative and multi-pass amplifiers. The system is well suited as pump laser for kHz high-average-power ultra-broadband OPCPAs. '2010 Optical Society of America


Ultrabroadband Optical Parametric Chirped Pulse Amplifier System For Single-Cycle Waveform Synthesis, Shu-Wei Huang, Giovanni Cirmi, Jeffrey Moses, Kyung-Han Hong, Andrew Benedick, Li-Jin Chen, Enbang Li, Benjamin J. Eggleton, Giulio Cerullo, Franz X. Kartner Jan 2010

Ultrabroadband Optical Parametric Chirped Pulse Amplifier System For Single-Cycle Waveform Synthesis, Shu-Wei Huang, Giovanni Cirmi, Jeffrey Moses, Kyung-Han Hong, Andrew Benedick, Li-Jin Chen, Enbang Li, Benjamin J. Eggleton, Giulio Cerullo, Franz X. Kartner

Faculty of Engineering and Information Sciences - Papers: Part A

We demonstrate synchronized few-cycle 800-nm and 2-μm pulse trains seeded from a single Ti:sapphire oscillator, able to generate scalable, high-energy pulses lasting less than a single electric-field cycle. Such pulses are attractive for high-field physics.


A Study On Saline Water Intrusion And Fresh Water Recharge Relevant To Coastal Environment, Sudip Basack, Amartya Kumar Bhattacharya, Chitta Sahana, Prabir Maity Jan 2010

A Study On Saline Water Intrusion And Fresh Water Recharge Relevant To Coastal Environment, Sudip Basack, Amartya Kumar Bhattacharya, Chitta Sahana, Prabir Maity

Faculty of Engineering and Information Sciences - Papers: Part A

The paper is based on experimental laboratory model study with relevant mathematical analysis followed by field investigation so as to understand the characteristics and flow pattern of saline water intrusion into natural porous medium followed by subsequent fresh water recharge.


A Hybrid Highly Birefringent Fiber Optic Sensing System For Simultaneous Strain And Temperature Measurement, Piotr Lesiak, Ginu Rajan, Yuliya Semenova, Gerald Farrell, Anna Boczkowska, Andrzej Domanski, Tomasz Wolinski Jan 2010

A Hybrid Highly Birefringent Fiber Optic Sensing System For Simultaneous Strain And Temperature Measurement, Piotr Lesiak, Ginu Rajan, Yuliya Semenova, Gerald Farrell, Anna Boczkowska, Andrzej Domanski, Tomasz Wolinski

Faculty of Engineering and Information Sciences - Papers: Part A

A novel hybrid fiber optic sensor based on integration of polarimetric fiber sensors for simultaneous strain and temperature measurement is presented in this paper. Two types of polarimetric fibers are used: a side-hole fiber and a polarization maintaining photonic crystal fiber. The disadvantage of each sensor type can be overcome by using the sensors in a complementary manner to measure temperature independently from average strain. © 2010 Photonics Society of Poland.


Finite Element Prediction Of Plate-End Cover Separation In Frp-Strengthened Rc Beams, S S. Zhang, J G. Teng Jan 2010

Finite Element Prediction Of Plate-End Cover Separation In Frp-Strengthened Rc Beams, S S. Zhang, J G. Teng

Faculty of Engineering and Information Sciences - Papers: Part A

The flexural strength of reinforced concrete (RC) beams can be effectively increased using either externally bonded (EB) or near-surface mounted (NSM) fibre-reinforced polymer (FRP) reinforcement. A likely failure mode of such FRP-strengthened RC beams is the plate-end cover separation failure mode which involves debonding of the bonded FRP reinforcement and the cover concrete along the level of the steel tension reinforcement. Despite many existing studies on this failure mode, the accurate prediction of this failure mode using the finite element (FE) method has remained a great challenge. This paper presents a novel FE smeared-crack approach for accurate prediction of plate-end ...


Where To Place Product Reviews? An Information Search Process Perspective, Mengxiang Li, Chuan-Hoo Tan, Kwok-Kee Wei, Kanliang Wang Jan 2010

Where To Place Product Reviews? An Information Search Process Perspective, Mengxiang Li, Chuan-Hoo Tan, Kwok-Kee Wei, Kanliang Wang

Faculty of Engineering and Information Sciences - Papers: Part A

Online product reviews could be presented as expert reviews and user reviews. However, a fundamental question that is not fully understood, and which this study addresses, is: Where should product reviews be displayed so as to positively affect a consumer's decision-making performance? We focus on evaluating the impact of the placements and the source of reviews (i.e., the pre-screening or post-screening display of experts' or users' comments) on consumer behavior. Building on the underpinnings of Kuhlthau's model of information search process, we propose that the Expert-User product review provision (i.e., placing the expert reviews before the ...


Spatial And Temporal Interpolation Of Environmental Data, Tom Smith, Phil Jones, Elizabeth Kent, Maurice Cox, Noel A. Cressie, Dick Dee, Richard Smith Jan 2010

Spatial And Temporal Interpolation Of Environmental Data, Tom Smith, Phil Jones, Elizabeth Kent, Maurice Cox, Noel A. Cressie, Dick Dee, Richard Smith

Faculty of Engineering and Information Sciences - Papers: Part A

Environmental data analyzed to a regular spatial and temporal grid is often desired for monitoring and climate studies. For example, monitoring of regional to global temperature change and changes in the daily temperature range and extremes may use analyzed temperatures. We use the term 'analyses' in the broadest sense to encompass any form of transformation to a regular grid (so from simple gridding through to dynamical reanalyses). Resolution depends on the period and region of the analysis: typically coarser analysis grids correspond to longer periods and larger areas. Some analyses are updated in near-real time.


The (Statistical) Science Of Sustainability, Noel A. Cressie Jan 2010

The (Statistical) Science Of Sustainability, Noel A. Cressie

Faculty of Engineering and Information Sciences - Papers: Part A

I take as a basic law of nature that "trees do not grow to the sky". In fact, the tree metaphor is very useful as we try to impose a science on the vaguely defined term, "sustainability." Trees make up forests and forests grow and recede according to many factors. Trees develop from seeds to saplings to mature trees, using nutrients and water in the soil and C02, O2 and light from the atmosphere to grow. They do not grow to the sky, and they eventually dies. Forests do not cover the earth; but they grow, recede, and are potentially ...


Statistical Interpolation Methods, Richard Smith, Noel A. Cressie Jan 2010

Statistical Interpolation Methods, Richard Smith, Noel A. Cressie

Faculty of Engineering and Information Sciences - Papers: Part A

Statistical methods of interpolation are all based on assuming that the process being reconstructed (for the purpose of this report, a temperature field in space or time or both) can be modeled as a random process. The best-known examples occur in spatial statistics, including the technique widely known as kriging, and in time series analysis. The process may depend on unknown parameters, which have to be estimated as part of the interpolation procedure. Once the process is specified, including any estimated parameters, optimal interpolators are calculated either by finding the best linear interpolator (the linear combination of known observations that ...


Uniform Regularity In A Wedge And Regularity Of Traces Of Cr Functions, Luca Baracco, Stefano Pinton, Tran Vu Khanh Jan 2010

Uniform Regularity In A Wedge And Regularity Of Traces Of Cr Functions, Luca Baracco, Stefano Pinton, Tran Vu Khanh

Faculty of Engineering and Information Sciences - Papers: Part A

No abstract provided.


Numerical Investigation Of The Transient Multiphase Flow In An Ironmaking Blast Furnace, Zongyan Zhou, Haiping Zhu, Aibing Yu, Paul Zulli Jan 2010

Numerical Investigation Of The Transient Multiphase Flow In An Ironmaking Blast Furnace, Zongyan Zhou, Haiping Zhu, Aibing Yu, Paul Zulli

Faculty of Engineering and Information Sciences - Papers: Part A

Discrete particle simulation (DPS) has been applied to multiphase flow modelling in an ironmaking blast furnace (BF), including burden distribution at the top, gas-solid flow in the BF shaft and raceway, and liquid-solid flow in the hearth. In this work, the approach is further extended to take into account the transient features of gas and particle flow coupled with liquid tapping operation. In the simulation, two types of particles of coke and ore with different physical properties are considered, together with different shapes of the cohesive zone and the shrinkage of size of ore particles in the cohesive zone to ...


Simulation Of Macroscopic Deformation Using A Sub-Particle Dem Approach, Leela Kempton, David J. Pinson, Sheng Chew, Paul Zulli, Aibing Yu Jan 2010

Simulation Of Macroscopic Deformation Using A Sub-Particle Dem Approach, Leela Kempton, David J. Pinson, Sheng Chew, Paul Zulli, Aibing Yu

Faculty of Engineering and Information Sciences - Papers: Part A

A limitation in numerical modelling of the ironmaking blast furnace is the lack of ability to quantify the effects of particle deformation and subsequent loss of porosity arising from the softening and melting of ferrous materials. Previous attempts to consider deformation focussed solely on the macroscopic effects such as resistance to gas flow, with an assumed decrease in porosity proportional to temperature. Instead, it is proposed to approximate particle scale deformation using a modified subparticle Discrete Element Method approach, where each 'ore' particle is represented using an agglomerate of discrete elements with temperature dependent properties. Cohesive forces binding the agglomerate ...


A Λ-Cut And Goal-Programming-Based Algorithm For Fuzzy-Linear Multiple-Objective Bilevel Optimization, Ya Gao, Guangquan Zhang, Jun Ma, Jie Lu Jan 2010

A Λ-Cut And Goal-Programming-Based Algorithm For Fuzzy-Linear Multiple-Objective Bilevel Optimization, Ya Gao, Guangquan Zhang, Jun Ma, Jie Lu

Faculty of Engineering and Information Sciences - Papers: Part A

Bilevel-programming techniques are developed to handle decentralized problems with two-level decision makers, which are leaders and followers, who may have more than one objective to achieve. This paper proposes a λ-cut and goal-programming-based algorithm to solve fuzzy-linear multiple-objective bilevel (FLMOB) decision problems. First, based on the definition of a distance measure between two fuzzy vectors using λ-cut, a fuzzy-linear bilevel goal (FLBG) model is formatted, and related theorems are proved. Then, using a λ-cut for fuzzy coefficients and a goal-programming strategy for multiple objectives, a λ-cut and goal-programming-based algorithm to solve FLMOB decision problems is presented. A case study for ...


Multi-Criteria Group Decision Support With Linguistic Variables In Long-Term Scenarios For Belgian Energy Policy, Da Ruan, Jie Lu, Erik Laes, Guangquan Zhang, Jun Ma, Gaston Meskens Jan 2010

Multi-Criteria Group Decision Support With Linguistic Variables In Long-Term Scenarios For Belgian Energy Policy, Da Ruan, Jie Lu, Erik Laes, Guangquan Zhang, Jun Ma, Gaston Meskens

Faculty of Engineering and Information Sciences - Papers: Part A

Real world decisions often made in the presence of multiple, conflicting, and incommensurate criteria. Decision making requires multiple perspectives of different individuals as more decisions are made now in groups than ever before. This is particularly true when the decision environment becomes more complex such as sustainability policies study in environmental and energy sectors. Group decision making processes judgments or solutions for decision problems based on the input and feedback of multiple individuals. Multi-criteria decision and evaluation problems at tactical and strategic levels in practice involve fuzziness in terms of linguistic variables vis-à-vis criteria, weights, and decision maker judgments. Relevant ...


Collaborative Management Of Web Ontology Data With Flexible Access Control, Jie Lu, Chao Wang, Guangquan Zhang, Jun Ma Jan 2010

Collaborative Management Of Web Ontology Data With Flexible Access Control, Jie Lu, Chao Wang, Guangquan Zhang, Jun Ma

Faculty of Engineering and Information Sciences - Papers: Part A

The creation and management of ontology data on web sites (e.g. instance data that is used to annotate web pages) is important technical support for the growth of the semantic web. This study identifies some key issues for web ontology data management and describes an ontology data management system, called robinet, to perform the management. This paper presents the structure of the system and introduces a Web ontology data management model that enables a flexible access control mechanism. This model adds rules into the robinet system to utilize the semantics of ontology for controlling the access to ontology data ...


Team Situation Awareness Measure Using Semantic Utility Functions For Supporting Dynamic Decision-Making, Jun Ma, Jie Lu, Guangquan Zhang Jan 2010

Team Situation Awareness Measure Using Semantic Utility Functions For Supporting Dynamic Decision-Making, Jun Ma, Jie Lu, Guangquan Zhang

Faculty of Engineering and Information Sciences - Papers: Part A

Team decision-making is a remarkable feature in a complex dynamic decision environment, which can be supported by team situation awareness. In this paper, a team situation awareness measure (TSAM) method using a semantic utility function is proposed. The semantic utility function is used to clarify the semantics of qualitative information expressed in linguistic terms. The individual and team situation awareness are treated as linguistic possibility distributions on the potential decisions in a dynamic decision environment. In the TSAM method, team situation awareness is generated through reasoning and aggregating individual situation awareness based on a multi-level hierarchy mental model of the ...


A State-Based Knowledge Representation Approach For Information Logical Inconsistency Detection In Warning Systems, Jun Ma, Guangquan Zhang, Jie Lu Jan 2010

A State-Based Knowledge Representation Approach For Information Logical Inconsistency Detection In Warning Systems, Jun Ma, Guangquan Zhang, Jie Lu

Faculty of Engineering and Information Sciences - Papers: Part A

Detecting logical inconsistency in collected information is a vital function when deploying a knowledge-based warning system to monitor a specific application domain for the reason that logical inconsistency is often hidden from seemingly consistent information and may lead to unexpected results. Existing logical inconsistency detection methods usually focus on information stored in a knowledge base by using a well-defined general purpose knowledge representation approach, and therefore cannot fulfill the demands of a domain-specific situation. This paper first proposes a state-based knowledge representation approach, in which domain-specific knowledge is expressed by combinations of the relevant objects' states. Based on this approach ...


Comparison Of Thermal Stability In Max211 And 312 Phases, Wei Kong Pang, It-Meng Low, B H. O'Connor, Andrew J. Studer, Vanessa Peterson, Zheng-Ming Sun, J P. Palmquist Jan 2010

Comparison Of Thermal Stability In Max211 And 312 Phases, Wei Kong Pang, It-Meng Low, B H. O'Connor, Andrew J. Studer, Vanessa Peterson, Zheng-Ming Sun, J P. Palmquist

Faculty of Engineering and Information Sciences - Papers: Part A

The susceptibility of four MAX phases (Ti2AlC, Cr2AlC, Ti3AlC2, and Ti3SiC2) to high-temperature thermal dissociation in vacuum has been investigated using in-situ neutron diffraction.


Discriminative Maximum Margin Image Object Categorization With Exact Inference, Qinfeng Shi, Luping Zhou, Li Cheng, Dale Schuurmans Jan 2010

Discriminative Maximum Margin Image Object Categorization With Exact Inference, Qinfeng Shi, Luping Zhou, Li Cheng, Dale Schuurmans

Faculty of Engineering and Information Sciences - Papers: Part A

Categorizing multiple objects in images is essentially a structured prediction problem: the label of an object is in general dependent on the labels of other objects in the image. We explicitly model object dependencies in a sparse graphical topology induced by the adjacency of objects in the image, which benefits inference, and then use maximum margin principle to learn the model discriminatively. Moreover, we propose a novel exact inference method, which is used in training to find the most violated constraint required by cutting plane method. A slightly modified inference method is used in testing when the target labels are ...


Mechanism Of Sediment Transport In Uni-Directional, Bi-Directional Flows, Shu-Qing Yang Jan 2010

Mechanism Of Sediment Transport In Uni-Directional, Bi-Directional Flows, Shu-Qing Yang

Faculty of Engineering and Information Sciences - Papers: Part A

The aim of the present study is to investigate the relationship between flow strength and sediment discharge. The appropriate definition of energy dissipation rate E in Bagnold's theorem is discussed and it is found that the sediment transport rate g, in unidirectional and bi-directional flows can be well predicted when E is defined as the product of bed shear stress T. and near bed velocity u. then the linear relationship between u. E and the sediment transport rate is examined using measured data. The good agreement between measured and predicted values indicates that the phenomena of sediment transport can ...


Response Of 20 Laterally Loaded Piles In Sand, Wei-Dong Guo, Bi Tang Zhu Jan 2010

Response Of 20 Laterally Loaded Piles In Sand, Wei-Dong Guo, Bi Tang Zhu

Faculty of Engineering and Information Sciences - Papers: Part A

Closed-form solutions and their associated spreadsheet program (GASLFP) were developed by the first author for laterally loaded free- head piles in elastic-plastic media. The solutions show behaviour of a laterally loaded pile is dominated by net limiting force per unit length (LFP) fully mobilised along the pile to a depth called slip depth. They are characterised by three parameters of Ng, α o and n (to describe the LFP) and the soil shear modulus (Gs). Conversely, these parameters may be deduced by matching the predicted with measured response. To facilitate practical design, in this paper, the input values of Ng ...


Thrust And Bending Moment Of Rigid Piles Subjected To Moving Soil, Wei-Dong Guo, H Y. Qin Jan 2010

Thrust And Bending Moment Of Rigid Piles Subjected To Moving Soil, Wei-Dong Guo, H Y. Qin

Faculty of Engineering and Information Sciences - Papers: Part A

An experimental apparatus was developed to investigate the behaviour of vertically loaded free-head piles in sand undergoing lateral soil movement(wf). A large number of tests have been conducted to date. Presented herein are 14 typical model pile tests concerning 2 diameters, 2 vertical pile loading levels, and varying sliding depths with the movement Wf driven by a triangular loading block. The results are provided regarding driving force, and induced shear force (T), bending movement (M) and deflection (y) along the piles with Wf/ normalised sliding depth. The tests enable simple expressions to be proposed, capitalised on theory for laterally ...


Model Tests On Free-Standing Passive Pile Groups In Sand, Wei-Dong Guo, E. H. Ghee Jan 2010

Model Tests On Free-Standing Passive Pile Groups In Sand, Wei-Dong Guo, E. H. Ghee

Faculty of Engineering and Information Sciences - Papers: Part A

A number of tests have been conducted to investigate response of vertically loaded capped pile groups in sand undergoing uniform lateral soil movement. The development of shear force, bending moment and deflection along the piles was measured. Presented in this paper are 4 tests on 2-pile free-standing groups, with a view to establish solutions for predicting the pile response. It was concluded that (1) maximum bending moment Mmax is largely linearly related to the sliding force Tmax in stable and moving layers; (2) The combined impact of pile-cap fixity, soil movement profiles, and axial load may be quantified by a ...


Iterative Soft Compensation For Ofdm Systems With Clipping And Superposition Coded Modulation, Jun Tong, Li Ping, Zhonghao Zhang, Vijay Bhargava Jan 2010

Iterative Soft Compensation For Ofdm Systems With Clipping And Superposition Coded Modulation, Jun Tong, Li Ping, Zhonghao Zhang, Vijay Bhargava

Faculty of Engineering and Information Sciences - Papers: Part A

This paper deals with the clipping method used in orthogonal frequency-division multiplexing (OFDM) systems to reduce the peak-to-average power ratio (PAPR). An iterative soft compensation method is proposed to mitigate the clipping distortion, which can outperform conventional treatments. The impact of signaling schemes on the residual clipping noise power is studied via the symbol variance analysis. It is found that superposition coded modulation (SCM) can minimize the residual clipping noise power among all possible signaling schemes. This indicates that SCM-based OFDM systems are more robust to clipping effect than other alternatives when soft compensation is applied. It is also shown ...


High-Energy, Khz-Repetition-Rate, Ps Cryogenic Yb:Yag Chirped-Pulse Amplifier, Kyung-Han Hong, Juliet Gopinath, Darren Rand, Aleem M. Siddiqui, Shu-Wei Huang, Enbang Li, Benjamin J. Eggleton, John D. Hybl, Tso Yee Fan, Franz X. Kartner Jan 2010

High-Energy, Khz-Repetition-Rate, Ps Cryogenic Yb:Yag Chirped-Pulse Amplifier, Kyung-Han Hong, Juliet Gopinath, Darren Rand, Aleem M. Siddiqui, Shu-Wei Huang, Enbang Li, Benjamin J. Eggleton, John D. Hybl, Tso Yee Fan, Franz X. Kartner

Faculty of Engineering and Information Sciences - Papers: Part A

We demonstrate amplification of picosecond laser pulses to 40 mJ at a 2 kHz pulse repetition frequency (PRF) from a two-stage cryogenic chirped-pulse Yb:YAG amplifier, composed of a regenerative amplifier (RGA) and a two-pass booster amplifier. The RGA produces 8.2 mJ of energy at 2 kHz PRF and 13.2 mJ at 1 kHz PRF with excellent energy stability (~0.3% rms) and beam quality ( M2<1.1 ). Pulse stretching and compression are achieved by using a chirped fiber Bragg grating and a multilayer dielectric grating pair, respectively. Compressed 15 ps pulses from the RGA are obtained with a throughput efficiency of ~80% (~6.5 mJ for 2 kHz ). The booster amplifier further amplifies the pulses to 40 mJ at 2 kHz PRF, and ~32 mJ, ~15 ps pulses are expected after compression. The amplifier chain seeded from a femtosecond Yb-fiber laser enables the optical self-synchronization between signal and pump in optical parametric chirped-pulse amplifier applications.


Femtosecond Second-Harmonic Generation In Periodically Poled Lithium Niobate Waveguides Written By Femtosecond Laser Pulses, Zhangchao Huang, Chenghou Tu, Shuanggen Zhang, Yongnan Li, Fuyun Lu, Yaxian Fan, Enbang Li Jan 2010

Femtosecond Second-Harmonic Generation In Periodically Poled Lithium Niobate Waveguides Written By Femtosecond Laser Pulses, Zhangchao Huang, Chenghou Tu, Shuanggen Zhang, Yongnan Li, Fuyun Lu, Yaxian Fan, Enbang Li

Faculty of Engineering and Information Sciences - Papers: Part A

We present in this Letter the second-harmonic generation of femtosecond pulses in double-line-written waveguides fabricated in periodically poled lithium niobate (PPLN) with femtosecond laser pulses. In a 10-mm-long sample, a normalized conversion efficiency of 12.6% W−1 cm−2 has been achieved for 40 fs pump pulses with the wavelengths centered at 1550 nm. Simulation results show that in PPLN waveguides the FWHM of wavelength tuning curve for 40 fs pump pulses is 42 nm, which is 15 times of that for 40 ps pump pulses.


Mechanical Property Development During Uoe Forming Of Large Diameter Pipeline Steels, Andrii Kostryzhev, Martin Strangwood, Claire L. Davis Jan 2010

Mechanical Property Development During Uoe Forming Of Large Diameter Pipeline Steels, Andrii Kostryzhev, Martin Strangwood, Claire L. Davis

Faculty of Engineering and Information Sciences - Papers: Part A

Mechanical properties of large diameter welded steel pipes depend on the thermomechanically controlled rolled (TMCR) plate microstructure and UOE pipe-forming cold deformation sequence. Strength from plate to pipe may increase (work-hardening) or decrease (the Bauschinger effect). Bauschinger effect parameters depend on steel composition and plate processing history. The present study is examining two pipeline grades: X60 (Nb-alloyed) and X65 (Nb- and V-alloyed). Mechanical properties are determined by grain refinement, solid solution, precipitation strengthening mechanisms, and work-hardening (work-softening). The reverse deformation yield drop increases with an increase in the precipitate particle volume fraction and pre-strain. Annealing, leading to a decrease in ...


Bauschinger Effect In Microalloyed Steels: Part I. Dependence On Dislocation-Particle Interaction, Andrii Kostryzhev, Martin Strangwood, Claire L. Davis Jan 2010

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 ...


Impacts Of Coal Shrinkage, Permeability And Petrography On Gas Regime In Mines Case Study: Tahmoor Coal Mine, Nsw, Australia, Naj Aziz, Ian Porter, F Sereshki Jan 2010

Impacts Of Coal Shrinkage, Permeability And Petrography On Gas Regime In Mines Case Study: Tahmoor Coal Mine, Nsw, Australia, Naj Aziz, Ian Porter, F Sereshki

Faculty of Engineering and Information Sciences - Papers: Part A

The volumetric changes in the coal matrix (Coal Shrinkage), permeability under various gas environment conditions as well as perographical properties were studied in the laboratory. The shrinkage and permeability of coal were examined with respect to changing gas type and confining pressures. The shrinkage tests were carried out in high-pressure bombs while the permeability study was conducted in a specially constructed high-pressure chamber. Methane (CH4), carbon dioxide (CO2), nitrogen, (N2) and a 50%-50% volume mixture of CO2/CH4 gas were used in the study. The tests showed that under different pressure levels gas type affected permeability and shrinkage characteristics ...