Engineering Commons^™

New Approaches To Controlling Unstable Gas Metal Arc Welding, Dominic Cuiuri, John Norrish, Christopher Cook

Dominic Cuiuri

This paper describes recent developments at the University of Wollongong in the application of novel control strategies to improve the control of inherently unstable transfer in the GMAW process. The paper reviews the problems involved in maintaining arc stability with CO2 shielded arcs and proposes potential solutions based on the development of a new process control technique. Results of early investigations into the phenomena are reported.

Novel Control Techniques For Co2 Shielded Gas Metal Arc Welding, Dominic Cuiuri, John Norrish, Christopher Cook

Dominic Cuiuri

The control strategies that have been developed over the past four decades to control the inherently unstable metal transfer in the CO2-shielded GMAW process are described. The fundamental reasons for poor arc stability with CO2 as a shielding gas are discussed. From an understanding of the process behaviour, a new process control technique is proposed, and the future direction of research in this area is discussed.

Engineering Design: Representation And Reasoning, Clive Dym, David Brown

David C. Brown

This text demonstrates that symbolic representation, and related problem-solving methods, offer significant opportunities to clarify and articulate concepts of design to give a better framework for design research and education. This edition includes recent work on design reasoning, computational design, AI in design, and design cognition, with pointers to the current literature.

An Alternative Current Control Approach For Dip Transfer Gmaw, Gary Dean, Dominic Cuiuri, John Norrish, Christopher Cook

Dominic Cuiuri

No abstract provided.

A New Approach To Controlled Short Circuit Transfer In Gmaw, John Norrish, Gary Dean, Dominic Cuiuri, Christopher Cook

Dominic Cuiuri

No abstract provided.

Investigation On Welding Arc Interruptions In The Presence Of Magnetic Fields: Arc Length, Torch Angle And Current Pulsing Frequency Influence, Ruham Reis, Americo Scotti, John Norrish, Dominic Cuiuri

Dominic Cuiuri

Arc interruptions have been observed in tandem pulsed gas metal arc welding (GMAW). This fact, which is likely related to magnetic interaction between the arcs, motivated previous study concerning the influence of the welding current on this phenomenon. In order to promote further understanding, this paper investigates the effects of arc length, torch angle, and high-frequency current pulsing on the arc resistance to extinction. To mimic the situation found in tandem GMAW (magnetic field induced by one arc acting on the other arc), external magnetic fields were applied to gas tungsten arc welding arcs. It was verified that short arc …

Droplet Size Regulation In The Short Circuit Gmaw Process Using A Controlled Current Waveform, Dominic Cuiuri, John Norrish, Christopher Cook

Dominic Cuiuri

Enhanced control of the short-circuit gas metal arc welding (GMAW) process can be achieved through the use of an advanced power source applying a controlled current waveform. By using a current waveform whose period is adapted to suit the requirements of the process, excellent welding performance can be achieved. When the current waveform is of fixed peak amplitude and shape, the control can be considered to be open-loop, as there is no active attempt to regulate a specific process parameter such as arc length, fusion area or dipping frequency. There is scope for more sophisticated control of the process. Using …

Miab Welding Of Oil And Gas Pipelines, L. Fletcher, Gabriel Stecher, Cec Stubbs, John Norrish, Dominic Cuiuri, Jeffrey Moscrop

Dominic Cuiuri

No abstract provided.

Verstatile Welding Power Source Controller For Research And Product Development, Dominic Cuiuri, John Norrish

Dominic Cuiuri

The diminishing cost and increasing speed of microprocessors has made them ubiquitous in modern welding control equipment, whether it is mass produced or custom made for research purposes.

Investigation Of Particulate Fume Generated From The Gmaw Of Plain Carbon Steel, Zoran Sterjovski, J Brossier, E De Thoisy, Dominic Cuiuri, John Norrish, Brian Monaghan

Dominic Cuiuri

No abstract provided.

A Flexible Computer-Controlled Experimental Power Source For Welding Research, Dominic Cuiuri, John Norrish, Christopher Cook

Dominic Cuiuri

Control of the Gas Metal Arc welding process is becoming increasingly sophisticated, due to improvements in technology and a better understanding of the process itself. To effectively conduct research in this area, it is necessary to have equipment that is extremely flexible in both architecture and operation. Experimental power sources and a welding test facility have been developed at the University of Wollongong which meet these criteria. The core time-critical control functions are performed by an independent digital signal processor (DSP). Non time-critical functions such as data storage and operator interface are performed by a desktop personal computer. Both computing …

Modelling And Simulation Of The Magnetically Impelled Arc Butt (Miab) Process For Transmission Pipeline Applications, John Norrish, Dominic Cuiuri, Mohammad Hossain

Dominic Cuiuri

Early patents for the Magnetically Impelled Arc Butt process (MIAB) date back to 1940 [1] and the basic principles of the process have remained unchanged from this time. The process was however refined in the 1970s for use in the production of automotive components and has been used extensively in this area. Investigation of the process for pipe girth welding have been reported and commercial pipe welding heads are reported to be available in the Ukraine [2], Although the process is well established it is believed that a more fundamental analysis of the mechanisms involved would assist in the optimisation …

Investigation On Welding Arc Interruptions In The Presence Of Magnetic Fields: Welding Current Influence, Ruham Reis, Americo Scotti, John Norrish, Dominic Cuiuri

Dominic Cuiuri

Arc interruptions and, therefore, oscillation in the amount of energy and molten wire delivered to the plate have been observed during tandem pulsed gas metal arc welding (GMAW). It appears that these instabilities are related to the magnetic interaction between the arcs. In order to clarify the possible mechanisms involved, this paper tries to mimic the tandem GMAW arc interruptions. External magnetic fields were dynamically applied to GTAW arcs in constant current mode to verify their resistance to extinction as a function of current level and direction of deflection. High-speed filming was carried out as an additional tool to understand …

Characterization Of Ten Channel Electro-Optic Phase Modulator And Amplifier In Algaas/Gaas, David Brown

David C. Brown

No abstract provided.

Investigations Of Tandem Gma Welding Using A Flexible Computer Controlled Power Source System, Ruham Reis, John Norrish, Dominic Cuiuri, Alexander Nicholson

Dominic Cuiuri

No abstract provided.

Influence Of Shielding Gas On Fume Formation Rate And Particle Size Distribution For Optimised Gmaw, Kristin Carpenter, Brian Monaghan, Alexander Nicholson, Dominic Cuiuri, John Norrish

Dominic Cuiuri

The influence of shielding gas on fume formation rate (FFR) and particle size distribution has been investigated by using a technique developed for automatic control of the welding voltage in gas metal arc welding (GMAW). The results for automatic control are compared with the use of a fixed voltage. Significant reductions in FFR and a general decrease in average particle size were observed using the automatic control technique. This reduction in FFR was attributed to improved metal transfer stability, via a reduction in the occurrence of repelled globular transfer, by promoting the 'drop-spray' transfer condition, together with a reduction in …

Material Properties And Microstructural Characterization Of Specimens, T.J. Silverman, Allison Kinney, B. South, W. Yong, J.H. Koo

Allison Kinney

The HiQ upgrade to the 3D Systems Vanguard selective laser sintering (SLS) machine incorporates a revised thermal calibration system and new software. This paper quantifies differences in mechanical and morphological properties of specimens built first using a Vanguard HS (high-speed) system and again using the same system with the HiQ upgrade applied. Standard specimens are built from DuraForm PA material and tested for tensile modulus, tensile strength, elongation at break, flexural modulus and Izod impact strength. The design of the specimen battery, the conduction of the tests and the significance of the results are discussed. The upgrade is found to …

A Versatile Experimental Test Rig For Gma Welding Research, Gary Dean, Dominic Cuiuri, John Norrish, Christopher Cook

Dominic Cuiuri

Welding process research is severely hampered when adequate experimental equipment is not available. With the development of numerous welding processes and the control techniques associated with them, the need now exists for experimental equipment that offers the flexibility to control these processes and to set up parameters associated with the research. At the University of Wollongong an experimental research rig has been developed based on a digital signal processor control system that offers the researcher the facilities to study the various processes associated with GMA welding.

A Flexible Control Program For Research And Development In Tandem Gma Welding, Ruham Reis, John Norrish, Dominic Cuiuri, Alexander Nicholson

Dominic Cuiuri

No abstract provided.

Ftir Studies Of Ionic Interactions In Blends, Robert Weiss

Robert Weiss

No abstract provided.

Supercritical Carbon Dioxide Aided Preparation Of Conductive Polyurethane-Polypyrrole Composites, Robert Weiss

Robert Weiss

Conductive polyurethane (PU) foams were prepared using a two-step procedure. First, PU foams were impregnated with the oxidant I2 from a scCO2 solution. Subsequently, the foams were subjected to pyrrole vapor, which polymerized within the foam in the presence of the oxidant. The reduced form of iodine as a result of the oxidative polymerization of pyrrole functions as a dopant. The conductivities of the foams ranged from 10−7 to 10−2 S/cm and the foams were flexible and not brittle. The concentration of conductive polypyrrole, i.e. the PPy–I2 charge-transfer complex, needed to achieve a conductivity of 10−4–10−3 S/cm was about 22% …

Supercritical Carbon Dioxide Aided Preparation Of Conductive Polyurethane-Polypyrrole Composites, Robert Weiss

Robert Weiss

Conductive polyurethane (PU) foams were prepared using a two-step procedure. First, PU foams were impregnated with the oxidant I2 from a scCO2 solution. Subsequently, the foams were subjected to pyrrole vapor, which polymerized within the foam in the presence of the oxidant. The reduced form of iodine as a result of the oxidative polymerization of pyrrole functions as a dopant. The conductivities of the foams ranged from 10−7 to 10−2 S/cm and the foams were flexible and not brittle. The concentration of conductive polypyrrole, i.e. the PPy–I2 charge-transfer complex, needed to achieve a conductivity of 10−4–10−3 S/cm was about 22% …

Patient-Centered Appointment Scheduling Using Agent-Based Simulation, Tammy Toscos, Ayten Turkcan, Brad Doebbeling

Tammy R Toscos

Enhanced access and continuity are key components of patient-centered care. Existing studies show that several interventions such as providing same day appointments, walk-in services, after-hours care, and group appointments, have been used to redesign the healthcare systems for improved access to primary care. However, an intervention focusing on a single component of care delivery (i.e. improving access to acute care) might have a negative impact other components of the system (i.e. reduced continuity of care for chronic patients). Therefore, primary care clinics should consider implementing multiple interventions tailored for their patient population needs. We collected rapid ethnography and observations to …

Supply System’S Technology Configuration As A Contributor To End-User Vulnerability, Lindsay Robertson, Katina Michael, Albert Munoz

Professor Katina Michael

Individuals requiring goods and services essential to their mode of living, are increasingly vulnerable to failures of the complex, interlinked, and inhomogeneous technological systems that supply those needs. Extant analysis techniques do not adequately quantify, from an end-user’s perspective, the vulnerability that is contributed by such technological systems. This study explores the significance of inherent weaknesses of inhomogeneous technological systems and proposes an approach for measuring vulnerability as the individual end-user ‘exposure level’ for each service. The measure of "exposure" that is developed, is mapped directly from the configuration of a technological system. This measure of exposure allows quantitative evaluation …

Evaluation Of Thermal And Physical Properties Of Magnesium Nitride Powder: Impact Of Biofield Energy Treatment, Mahendra Kumar Trivedi, Rama Mohan Tallapragada, Alice Branton, Dahryn Trivedi, Gopal Nayak, Omprakash Latiyal, Snehasis Jana

Mahendra Kumar Trivedi

Cloud Computing Data Breaches: A Socio-Technical Review Of Literature, David Kolevski, Katina Michael

Professor Katina Michael

As more and more personal, enterprise and government data, services and infrastructure moves to the cloud for storage and processing, the potential for data breaches increases. Already major corporations that have outsourced some of their IT requirements to the cloud have become victims of cyber attacks. Who is responsible and how to respond to these data breaches are just two pertinent questions facing cloud computing stakeholders who have entered an agreement on cloud services. This paper reviews literature in the domain of cloud computing data breaches using a socio-technical approach. Socio-technical theory encapsulates three major dimensions- the social, the technical, …

Applying A Novel Combination Of Techniques To Develop A Predictive Model For Diabetes Complications, Mohsen Sangi, Khin Than Win, Farid Shirvani, Mohammad-Reza Namazi-Rad, Nagesh Shukla

Nagesh Shukla

No abstract provided.

A Lifetime Individual Sampling Model (Ism) For Heroin Use And Treatment Evaluation In Australia, Nagesh Shukla, Van Hoang, Marian Shahanan, Alison Ritter, Vu Lam Cao, Pascal Perez

Nagesh Shukla

Illicit drug use has created an enormous burden at societal, family and personal levels. Every year a significant amount of resources is allocated for treatment and the consequences of illicit drug use in Australia and around the world. Heroin is one of the major forms of illicit drugs that are used illegally. Several independent heroin treatment strategies or interventions exist and state-of-the-art research demonstrates their efficacy and relative cost-effectiveness. However, assessing total potential gains and burden from providing all treatment interventions or varying the mix of heroin treatments has never been attempted. Furthermore, the need to include multiple treatments, multiple …

Potential Impact Of Biofield Energy Treatment On The Atomic, Physical And Thermal Properties Indium Powder, Mahendra Kumar Trivedi, Rama Mohan Tallapragada, Alice Branton, Dahryn Trivedi, Gopal Nayak, Omprakash Latiyal, Snehasis Jana

Mahendra Kumar Trivedi

Competitive Adsorption Of Metals On Cabbage Waste From Multi-Metal Solutions, M Hossain, H Ngo, W Guo, L Nghiem, F Hai, S Vigneswaran, Thanh Vinh Nguyen

Faisal I Hai

This study assessed the adsorption capacity of the agro-waste ‘cabbage’ as a biosorbent in single, binary, ternary and quaternary sorption systems with Cu(II), Pb(II), Zn(II) and Cd(II) ions. Dried and ground powder of cabbage waste (CW) was used for the sorption of metals ions. Carboxylic, hydroxyl, and amine groups in cabbage waste were found to be the key functional groups for metal sorption. The adsorption isotherms obtained could be well fitted to both the mono- and multi-metal models. In the competitive adsorption systems, cabbage waste adsorbed larger amount of Pb(II) than the other three metals. However, the presence of the …