Science and Technology Studies Commons^™

Analysis Of Sintering And Bonding Of Ultrafine Wc Powder And Stainless Steel By Hot Compaction Diffusion Bonding, Mahadi Hasan, Jingwei Zhao, Zhenyi Huang, Li Chang, Haoruo Zhou, Zhengyi Jiang

Faculty of Engineering and Information Sciences - Papers: Part B

Bonding between tungsten carbide and steel is a challenging task due to their large difference of physical properties. Previous reports were based on solid state bonding. In this study, a powder-solid mechanism was employed for analysing the sintering and bonding process of ultrafine WC (with 8% Co added as binder) powder and solid stainless steel (SS 304). A novel manufacturing mechanism of hot compaction diffusion bonding (HCDB) was implemented to facilitate the bonding process. The influence of temperature varying from 1160 to 1220 °C was investigated with an interval of 20 °C. The experiment is conducted in a vacuum environment …

Graded Steinberg Algebras And Their Representations, Pere Ara, Roozbeh Hazrat, Huanhuan Li, Aidan Sims

Faculty of Engineering and Information Sciences - Papers: Part B

We study the category of left unital graded modules over the Steinberg algebra of a graded ample Hausdorff groupoid. In the first part of the paper, we show that this category is isomorphic to the category of unital left modules over the Steinberg algebra of the skew-product groupoid arising from the grading. To do this, we show that the Steinberg algebra of the skew product is graded isomorphic to a natural generalisation of the Cohen-Montgomery smash product of the Steinberg algebra of the underlying groupoid with the grading group. In the second part of the paper, we study the minimal …

Let's Get Moving With The Affordable Medium-Speed Alternatives To The Old Dream Of High-Speed Rail, Philip G. Laird

Faculty of Engineering and Information Sciences - Papers: Part B

More than half a century has passed since high-speed rail (HSR) effectively began operating, in Japan in 1964, and it has been mooted for Australia since 1984. I estimate that the cost of all HSR studies by the private and public sectors in Australia exceeds $125 million, in today's dollars. But the federal government is now less interested in high-speed rail (now defined as electric trains operating on steel rails at maximum speeds of above 250km per hour), and instead favours "faster rail" or medium-speed rail.

Fast Quasi-Newton Algorithms For Penalized Reconstruction In Emission Tomography And Further Improvements Via Preconditioning, Yu-Jung Tsai, Alexandre B. Bousse, Matthias J. Ehrhardt, Charles Stearns, Sangtae Ahn, Brian F. Hutton, Simon R. Arridge, Kris Thielemans

Faculty of Engineering and Information Sciences - Papers: Part B

This paper reports on the feasibility of using a quasi-Newton optimization algorithm, limited-memory Broyden- Fletcher-Goldfarb-Shanno with boundary constraints (L-BFGSB), for penalized image reconstruction problems in emission tomography (ET). For further acceleration, an additional preconditioning technique based on a diagonal approximation of the Hessian was introduced. The convergence rate of L-BFGSB and the proposed preconditioned algorithm (L-BFGS-B-PC) was evaluated with simulated data with various factors, such as the noise level, penalty type, penalty strength and background level. Data of three 18F-FDG patient acquisitions were also reconstructed. Results showed that the proposed L-BFGS-B-PC outperforms L-BFGS-B in convergence rate for all simulated conditions …

A Silicon Strip Detector Array For Energy Verification And Quality Assurance In Heavy Ion Therapy, Emily Debrot, Matthew Newall, Susanna Guatelli, Marco Petasecca, Naruhiro Matsufuji, Anatoly B. Rosenfeld

Faculty of Engineering and Information Sciences - Papers: Part B

Purpose

The measurement of depth dose profiles for range and energy verification of heavy ion beams is an important aspect of quality assurance procedures for heavy ion therapy facilities. The steep dose gradients in the Bragg peak region of these profiles require the use of detectors with high spatial resolution. The aim of this work is to characterize a one dimensional monolithic silicon detector array called the “serial Dose Magnifying Glass” (sDMG) as an independent ion beam energy and range verification system used for quality assurance conducted for ion beams used in heavy ion therapy.

Methods

The sDMG detector consists …

An Assessment Of Set Up Position For Mri Scanning For The Purposes Of Rectal Cancer Radiotherapy Treatment Planning, Ewa Juresic, Gary P. Liney, Robba Rai, Joseph Descalar, Mark T. Lee, Karen Ms Karen Wong, Daniel Moses, Jacqueline Veera, Lois C. Holloway

Faculty of Engineering and Information Sciences - Papers: Part B

Introduction

A magnetic resonance (MR) scanner for radiotherapy treatment simulation was commissioned in our department in June 2013. Practical set up and MR image quality trade‐offs using a variety of patient positions and immobilisation devices routinely used in the treatment planning of rectal cancer patients were considered. The study also aimed to investigate the MR compatibility of the device materials with a focus on temperature changes during routine clinical examinations.

Methods

Ten volunteers were scanned: (1) Prone on a Civco Contoura Bellyboard (BBB), (2) Prone on a Civco MR Series Bellyboard (WBB), (3) Prone with no bellyboard and (4) Supine. …

A Disturbance Observer-Based Robust Controller Design For Systems With Right Half Plane Zeros And Poles, Emre Sariyildiz, Ilhan Mutlu, Rahim Mutlu

Faculty of Engineering and Information Sciences - Papers: Part B

This paper analytically derives the bandwidth limitations of Disturbance Observer (DOB) when plants have Right Half Plane (RHP) zero(s) and pole(s). If the plant is non-minimum phase, then the bandwidth of DOB should be set at a lower value than its upper bound to improve the robust stability and performance. If the plant is unstable, then the bandwidth of DOB should be set at a higher value than its lower bound to achieve the robust stability. The upper and lower bounds are analytically derived by using Poisson integral formula. It is shown that the bandwidth limitation of DOB is directly …

Study Of Reaction Sequences During Msr Synthesis Of Tic By Controlled Ball Milling Of Titanium And Graphite, Erhuvwu J. Oghenevweta, David Wexler, Andrzej Calka

Faculty of Engineering and Information Sciences - Papers: Part B

During reactive ball milling of Ti and C, mechanically induced self-propagating reaction (MSR) synthesis of TiC is reported to occur via a process including initial formation of small amounts of TiC prior to exothermic ignition, followed by MSR and the formation of stiochiometric TiC (Dorofeev et al., 2011; Oghenevweta et al., 2016 [1, 2]). However, both the chemical evolution and mechanisms of reaction and growth of TiC both prior to, during and after ignition are not fully understood. This research focuses on fundamental understanding of the reaction sequences during MSR synthesis of TiC from elemental Ti and C (graphite).

Magnetically …

An Energy Saving Variable Damping Seat Suspension System With Regeneration Capability, Donghong Ning, Haiping Du, Shuaishuai Sun, Wenfei Li, Weihua Li

Faculty of Engineering and Information Sciences - Papers: Part B

In this paper, an energy saving variable damping seat suspension system is designed, manufactured and validated. A controllable electromagnetic damper (EMD), which consists of a permanent magnet synchronous motor (PMSM), a 3-phase rectifier, a metal-oxide-semiconductor field-effect transistor (MOSFET) switch module, an external resistor, a diode, and a capacitor, is designed and tested firstly. The EMD is integrated with a planetary gearbox to amplify its torque output, and both of them are installed on the centre of the scissors structure of a seat suspension. The EMD's damping property can be controlled by exerting pulse width modulation (PWM) signal with different duty …

Laser Self-Mixing Fiber Bragg Grating Sensor For Acoustic Emission Measurement, Bin Liu, Yuxi Ruan, Yanguang Yu, Jiangtao Xi, Qinghua Guo, Jun Tong, Ginu Rajan

Faculty of Engineering and Information Sciences - Papers: Part B

Fiber Bragg grating (FBG) is considered a good candidate for acoustic emission (AE) measurement. The sensing and measurement in traditional FBG-based AE systems are based on the variation in laser intensity induced by the Bragg wavelength shift. This paper presents a sensing system by combining self-mixing interference (SMI) in a laser diode and FBG for AE measurement, aiming to form a new compact and cost-effective sensing system. The measurement model of the overall system was derived. The performance of the presented system was investigated from both aspects of theory and experiment. The results show that the proposed system is able …

Selection Of Fan(S) To Dilute Dpm For Multi-Seam Board And Pillar Coal Mines Using Hardy Cross And Cpm Methods, Ramakrishna Morla, Shivakumar Karekal

Faculty of Engineering and Information Sciences - Papers: Part B

Multi-seam coal mining comprises of a large number of working sections. A well-organized ventilation system is necessary to supply adequate air quantities to all working sections and to dilute diesel particulate matter (DPM) within the statutory limits. In this paper, an attempt has been made to optimize fan(s) operating points in a multi-seam mine using a combination of Hardy-Cross and critical path methods. Selection of parallel fan sizes was further explored using computational fluid dynamics (CFD). Simulation results show that operating two surface parallel fans results in low total air power and low fans pressure

Influence Of Particle Gradation And Shape On The Performance Of Stone Columns In Soft Clay, Firman Siahaan, Buddhima Indraratna, Ngoc Trung Ngo, Cholachat Rujikiatkamjorn, Ana Heitor

Faculty of Engineering and Information Sciences - Papers: Part B

A stone column typically consists of particles whose influence has largely been overlooked in design practice in terms of stress transfer, pattern of deformation, and intrusion of fines (clogging). This article presents an experimental study on the load-deformation behavior of a model stone column installed in soft clay with a particular emphasis on the influence of particle gradation and shape under undrained loading. The results show that particle gradation and shape have a significant influence on the load-deformation behavior and the extent of fines intrusion into the stone columns. Relatively well-graded particle sizes favor the development of higher peak shear …

An Online Condition Monitoring System Implemented An Internet Connectivity And Ftp For Low Speed Slew Bearing, Wahyu Caesarendra, Buyung Kosasih, Tegoeh Tjahjowidodo, Mochammad Ariyanto, L Daryl, Daniel Pamungkas

Faculty of Engineering and Information Sciences - Papers: Part B

Rapid and reliable information in slew bearing maintenance is not trivial issue. This paper presents the online monitoring system to assist maintenance engineer in order to monitor the bearing condition of low speed slew bearing in sheet metal company. The system is able to pass the vibration information from the place where the bearing and accelerometer sensors are attached to the data center; and from the data center it can be access by opening the online monitoring website from any place and by any person. The online monitoring system is built using some programming languages such as C language, MATLAB, …

Plasticity Improvement Of Ball-Spun Magnesium Alloy Tube Based On Stress Triaxiality, Chunjiang Zhao, Feitao Zhang, Jie Xiong, Zhengyi Jiang, Xiaorong Yang, Hailong Cui

Faculty of Engineering and Information Sciences - Papers: Part B

The effects of thickness reduction, feed ratio, and ball diameter, and their coupling effects, on the average relative stress triaxiality during spinning are discussed via simulation results. The relationships among the parameters and the average value of relative stress triaxiality (AVRST) are fitted with multiple nonlinear functions to calculate the optimal process parameters. According to the trend of stress triaxiality, the corresponding process parameters are calculated for the minimum average value of relative stress triaxiality (AVRST). Room temperature experiments performed on an AZ31 magnesium alloy thin-walled tube with the optimal parameters reveal an improvement of cracking of the tube surface. …

Martens-Ite, Druce Patrick Dunne

Faculty of Engineering and Information Sciences - Papers: Part B

Martensite and martensitic transformations in metals and alloys have been intensively studied for more than a century and many comprehensive and informative reviews have been published. The current review differs insofar as the analysis is performed largely through the prism of detailed studies of the changes in the martensitic transformation in Fe3Pt alloy as a result of austenite ordering. This important alloy is the first ferrous alloy identified as exhibiting thermoelastic transformation and shape memory. The effect of parent phase order on the martensitic transformation offers significant insights into general understanding of the nature of martensitic transformation, particularly the factors …

Comparison Of Gmaw And Saw For Ngw Of 50 Mm Q&T Steel Plate, Druce Patrick Dunne, Willy Pang

Faculty of Engineering and Information Sciences - Papers: Part B

A one-pass-per-layer technique was used for narrow gap welding (NGW) of 50 mm thick plate of quenched and tempered steel with 690 MPa minimum yield strength. GMAW and SAW were investigated for pulsed and non-pulsed welding using the same 1.2 mm strength-matching welding consumable and the same nominal heat inputs for each of the pulsed and non-pulsed welds. The welds were defect-free and the hardness, tensile strength and Charpy impact energies were generally consistent with high weldment integrity. Pulsing of the welding current had the effect of slightly increasing side-wall fusion, flattening the weld bead and decreasing its volume. The …

A Novel High-Resolution 2d Silicon Array Detector For Small Field Dosimetry With Fff Photon Beams, Giordano Biasi, Marco Petasecca, Susanna Guatelli, Nicholas G. Hardcastle, Martin G. Carolan, Vladimir Perevertaylo, Tomas Kron, Anatoly B. Rosenfeld

Faculty of Engineering and Information Sciences - Papers: Part B

Purpose: Flattening filter free (FFF) beams are increasingly being considered for stereotactic radiotherapy (SRT). For the first time, the performance of a monolithic silicon array detector under 6 and 10 MV FFF beams was evaluated. The dosimeter, named "Octa" and designed by the Centre for Medical Radiation Physics (CMRP), was tested also under flattened beams for comparison. Methods: Output factors (OFs), percentage depth-dose (PDD), dose profiles (DPs) and dose per pulse (DPP) dependence were investigated. Results were benchmarked against commercially available detectors for small field dosimetry. Results: The dosimeter was shown to be a 'correction-free' silicon array detector for OFs …

High Spatial Resolution Microdosimetry With Monolithic Delta E-E Detector On C-12 Beam: Monte Carlo Simulations And Experiment, Linh T. Tran, David Bolst, Susanna Guatelli, Giordano Biasi, Alberto Fazzi, Elena Sagia, Dale A. Prokopovich, Mark I. Reinhard, Ying C. Keat, Marco Petasecca, Michael L. F Lerch, A Pola, Stefano Agosteo, Naruhiro Matsufuji, Michael A. Jackson, Anatoly B. Rosenfeld

Faculty of Engineering and Information Sciences - Papers: Part B

Nuclear fragmentation produced in ¹²C ion therapeutic beams contributes significantly to the Relative Biological Effectiveness (RBE)—weighted dose in the distal edge of the Spread out Bragg Peak (SOBP) and surrounding tissues in out-of-field. Complex mixed radiation field originated by the therapeutic ¹²C ion beam in a phantom is difficult to measure. This study presents a new method to characterise the radiation field produced in a ¹²C ion beam using a monolithic Delta E-E telescope which provides the capability to identify the particle components of the mixed radiation field as well as the microdosimetric spectra that allows derivation …

Investigations Of Ventilation Airflow Characteristics On A Longwall Face-A Computational Approach, Zhongwei Wang, Ting X. Ren, Liqiang Ma, Jian Zhang

Faculty of Engineering and Information Sciences - Papers: Part B

Mine ventilation has always been critical for underground mining operations to ensure operational efficiency and compliance with safety and health statutory requirements. To obtain a thorough understanding of the ventilation flow characteristics on a longwall face, innovative three dimensional (3D) models, incorporating key features of the longwall equipment and a zone of immediate goaf area, were developed. Mesh independent studies were conducted to determine the desirable mesh required for a mesh-independent solution. Then the model results were validated using field ventilation survey data. At both intersections of maingate/tailgate (MG/TG) and face where the flow boundary changes sharply, the occurrence of …

A Case Study Of Presplitting Blasting Parameters Of Hard And Massive Roof Based On The Interaction Between Support And Overlying Strata, Ningbo Zhang, Changyou Liu, Baobao Chen

Faculty of Engineering and Information Sciences - Papers: Part B

Due to the existence of a hard and massive roof (HMR), severe ground pressure behaviors have been observed at the working face, resulting in safety issues and the degradation of production effectiveness. Based on the HMR conditions of the Datong Mining Area, the fracture-related instability of the HMR and its effects on the support selection were investigated by analyzing the interaction between support and overlying strata. Advancefixed-distance presplitting blasting (AFPB) technology was proposed to control the caving interval of HMR, and the influence of the controlled interval on the working load of supports was also analyzed. The working load of …