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2015

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Articles 121 - 150 of 11606

Full-Text Articles in Engineering

Towards The Development Of A Wearable Tremor Suppression Glove, Yue Zhou Dec 2015

Towards The Development Of A Wearable Tremor Suppression Glove, Yue Zhou

Electronic Thesis and Dissertation Repository

Patients diagnosed with Parkinson’s disease (PD) often associate with tremor. Among other symptoms of PD, tremor is the most aggressive symptom and it is difficult to control with traditional treatments. This thesis presents the assessment of Parkinsonian hand tremor in both the time domain and the frequency domain, the performance of a tremor estimator using different tremor models, and the development of a novel mechatronic transmission system for a wearable tremor suppression device. This transmission system functions as a mechatronic splitter that allows a single power source to support multiple independent applications. Unique features of this transmission system include low …

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Development Of Highly Active And Stable Hybrid Cathode Catalyst For Pemfcs, Won Suk Jung Dec 2015

Development Of Highly Active And Stable Hybrid Cathode Catalyst For Pemfcs, Won Suk Jung

Theses and Dissertations

Polymer electrolyte membrane fuel cells (PEMFCs) are attractive power sources of the future for a variety of applications including portable electronics, stationary power, and automobile application. However, sluggish cathode kinetics, high Pt cost, and durability issues inhibit the commercialization of PEMFCs. To overcome these drawbacks, research has been focused on alloying Pt with transition metals since alloy catalysts show significantly improved catalytic properties like high activity, selectivity, and durability. However, Pt-alloy catalysts synthesized using the conventional impregnation method exhibit uneven particle size and poor particle distribution resulting in poor performance and/or durability in PEMFCs. In this dissertation, a novel catalyst …

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Wavelet Analysis Of Periodic Error In Heterodyne Interferometry, Chao Lu Dec 2015

Wavelet Analysis Of Periodic Error In Heterodyne Interferometry, Chao Lu

Theses and Dissertations

Heterodyne displacement measuring interferometry provides important metrology for applications requiring high resolution and accuracy. Heterodyne Michelson interferometers use a two-frequency laser source and separate the two optical frequencies into one fixed length and one variable length path via polarization. Ideally these two beams are linearly polarized and orthogonal so that only one frequency is directed toward each path. An interference signal is obtained by recombining the light from the two paths; this results in a measurement signal at the heterodyne (split) frequency of the laser source. This measurement signal is compared to the optical reference signal. Motion in the measurement …

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In Situ Ir Spectroscopic Investigation Of Noble Metal Catalysts Related To The Reduction Of Automotive Exhaust Emissions, Zhiyong Wang Dec 2015

In Situ Ir Spectroscopic Investigation Of Noble Metal Catalysts Related To The Reduction Of Automotive Exhaust Emissions, Zhiyong Wang

Theses and Dissertations

The reduction of automotive exhaust emissions has been one of the hottest topics in catalysis community since 1970s. Thanks to the development of three-way catalysts, main auto-exhaust pollutants, such as carbon monoxide, nitrogen oxides and unburned hydrocarbons, can be removed simultaneously. Nowadays, diesel engines and lean-engines become more and more popular due to their high fuel-efficiency and low CO2 emissions. Unfortunately, conventional three-way catalysts are not effective at reducing the NOx emissions from these engines due to the excess oxygen in the exhaust stream. Platinum catalysts were found to be highly active for selective NO reduction with hydrocarbons in excess …

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Tool Material Degradation Due To Friction Stir Welding Of Aluminum Alloys, Corbin T. Collier Dec 2015

Tool Material Degradation Due To Friction Stir Welding Of Aluminum Alloys, Corbin T. Collier

Theses and Dissertations

The purpose of this study is to investigate the friction stir welding (FSW) tool material degradation factors due variation in tool material properties and the effect of an aluminum diffusion wear mechanism on three different FSW tool material when exposed to various welding temperatures and times. The degradation factors are essential to FSW tool design due to the effect of the tool pin and shoulders on the heat generation and material flow which directly correlated to the weld quality created during the FSW process. For this investigation the three materials used are H13, TSP1, and MP159. To determine degradation factors …

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Preparation And Characterization Of Pt-Ru Bimetallic Catalysts Using Electroless Deposition Methods And Mechanistic Study Of Re And Cs Promoters For Ag-Based, High Selectivity Ethylene Oxide Catalysts, Weijian Diao Dec 2015

Preparation And Characterization Of Pt-Ru Bimetallic Catalysts Using Electroless Deposition Methods And Mechanistic Study Of Re And Cs Promoters For Ag-Based, High Selectivity Ethylene Oxide Catalysts, Weijian Diao

Theses and Dissertations

Pt-Ru bimetallic catalysts are widely used for direct methanol fuel cells, biomass upgrading and hydrocarbon refining and offer unique properties compared to Pt or Ru monometallic catalysts due to ensemble effects, electronic effects, and/or bifunctional effects. To achieve better performance, strong metal-metal interactions and true bimetallic surface are needed. Electroless deposition (ED) methods are used in our laboratory to synthesize such bimetallic catalysts. In this study, two series of Ru@Pt/C (Pt deposited on Ru surfaces) and Pt@Ru/C (Ru deposited on Pt surfaces) catalysts have been synthesized. Characterization data from temperature programmed reduction (TPR), selective chemisorption, X-ray photoelectron spectroscopy (XPS), and …

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Slope Stability Enhancement Of An Upstream Tailings Dam: Laboratory Testing And Numerical Modelling, Yazeed A. Alsharedah Dec 2015

Slope Stability Enhancement Of An Upstream Tailings Dam: Laboratory Testing And Numerical Modelling, Yazeed A. Alsharedah

Electronic Thesis and Dissertation Repository

Mine tailings are the byproduct of mining activities, which need to be disposed of once the ore is extracted. They can be disposed of in either dry or wet forms. The latter is most common with the tailings being disposed of in the form of slurry inside retention structures. The retention structure may be a natural, manmade, or built dam, which is the case in most of nowadays mining locations. In this thesis, improving the stability of an upstream tailings dam using soil additives is investigated. The experimental phase of this study involved laboratory tests conducted to characterize mine tailings …

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Guidelines For Using Process Mapping To Aid Improvement Efforts, Paul Savory, John Olson Dec 2015

Guidelines For Using Process Mapping To Aid Improvement Efforts, Paul Savory, John Olson

John Olson

Process mapping is an easy-to-visualize method for people to analyze and agree on the most efficient routes for reengineering or improving a process. It aids in determining redundant tasks, uncovering hidden interactions between processes and people, and focusing on the processes that serve customers, improve quality, and generate income. This paper presents guidelines for using process mapping as an improvement tool. It is based on the authors’ experiences in aiding a variety of healthcare, service, and manufacturing companies.

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A New Saifi Based Voltage Sag Index, Robert Barr, V. Gosbell, Ian Mcmichael Dec 2015

A New Saifi Based Voltage Sag Index, Robert Barr, V. Gosbell, Ian Mcmichael

Robert Barr

Reliability measures of SAIDI (system average interruption duration index) and SAIFI (system average frequency index) are well established industry standards used world wide. While both measures have their limitations, they give a broad indication of average reliability that allows comparison within networks and across networks world wide. No such industry standard indices exist for voltage sags. The main reason being that voltage sags are multi-dimensional, involving retained sag voltage, sag duration, number of phases effected, phase angle jumps and the time between successive sags. This paper proposes a new voltage sag index that is dimensionally the same as SAIFI having …

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Preliminary Evaluations On Laser - Tandem Gmaw, Ruham Reis, John Norrish, Dominic Cuiuri Dec 2015

Preliminary Evaluations On Laser - Tandem Gmaw, Ruham Reis, John Norrish, Dominic Cuiuri

Dominic Cuiuri

Recently there has been considerable research and development activity in the use of lasers for welding operations, turning this process into an important tool for a variety of applications. Although it is possible to use lasers as a unique source of heat to promote union of materials, the combination of the beam provided by a laser system with an arc welding process has been studied widely and applied in the so-called hybrid welding systems. Generally, the final result of such a combination is an increase in the weld penetration depth, width and welding travel speed. Despite these advantages, there are …

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Cracking The Shell To Student Learning: An Innovative Instructional Approach, John Olson, Paul Savory Dec 2015

Cracking The Shell To Student Learning: An Innovative Instructional Approach, John Olson, Paul Savory

John Olson

Management and Industrial Engineering courses is motivating students to learn and apply the quantitative and managerial aspects of the material. The aim of our educational methodology is to not only teach and reinforce the core principles of the disciplines, but to have students develop a set of skills that will make them competitive in the classroom and the workforce. Teaching is why a university exists. As a result, the objective of our instructional approach is to attract and retain dedicated students to the fields of Operations Management and Industrial Engineering and to keep those students competitive and in focus with …

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Road Rescue Implements A Continuous Process Improvement Framework, John Olson, Paul Savory Dec 2015

Road Rescue Implements A Continuous Process Improvement Framework, John Olson, Paul Savory

John Olson

Continuous improvement programs traditionally focus on making small incremental improvements to a system. Unfortunately, their success can be limited due to the rapid changing environment within which most small companies operate. Improvement efforts should be flexible enough to capitalize on incremental and radical changes to a system. This paper presents a case analysis of how Road Rescue, an ambulance manufacturer, uses a continuous improvement framework to capitalize on both radical and incremental improvement opportunities. Results include a 10% increase in throughput, reduced cycle time of 44%, increased customer satisfaction, and higher quality.

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New Approaches To Controlling Unstable Gas Metal Arc Welding, Dominic Cuiuri, John Norrish, Christopher Cook Dec 2015

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.

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Novel Control Techniques For Co2 Shielded Gas Metal Arc Welding, Dominic Cuiuri, John Norrish, Christopher Cook Dec 2015

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.

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Constrained Biogeography-Based Optimization For Invariant Set Computation,, Arpit Shah, Daniel Simon, Hanz Richter Dec 2015

Constrained Biogeography-Based Optimization For Invariant Set Computation,, Arpit Shah, Daniel Simon, Hanz Richter

Hanz Richter

We discuss the application of biogeography-based optimization (BBO) to invariant set approximation. BBO is a recently developed evolutionary algorithm (EA) that is motivated by biogeography, which is the study and science of the geographical migration of biological species. Invariant sets are sets in the state space of a dynamic system such that if the state begins in the set, then it remains in the set for all time. Invariant sets have applications in many constrained control problems, and their computation amounts to a constrained optimization problem. We therefore frame the invariant set computation problem as a constrained optimization problem, and …

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Discovery Of Design Methodologies, Cirrus Shakeri, David Brown, Mohammad Noori Dec 2015

Discovery Of Design Methodologies, Cirrus Shakeri, David Brown, Mohammad Noori

David C. Brown

In this paper we present an AI-based approach for the discovery of design methodologies for multi-disciplinary design situations. The approach is based on simulating the design process using a multi-agent system that mimics the behavior of the design team. The system activates the pieces of design knowledge when they become applicable. The use of knowledge by agents is recorded by tracing the steps that the agents have taken during a design project. Many traces are generated by solving a large number of design projects that differ in their requirements. A set of design methodologies is constructed by using clustering techniques …

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Engineering Design: Representation And Reasoning, Clive Dym, David Brown Dec 2015

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.

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Combining Dynamic Stretch And Tunable Stiffness To Probe Cell Mechanobiology In Vitro, Angela Quinlan, Leslie Sierad, Andrew Capulli, Laura Firstenberg, Kristen Billiar Dec 2015

Combining Dynamic Stretch And Tunable Stiffness To Probe Cell Mechanobiology In Vitro, Angela Quinlan, Leslie Sierad, Andrew Capulli, Laura Firstenberg, Kristen Billiar

Kristen L. Billiar

Cells have the ability to actively sense their mechanical environment and respond to both substrate stiffness and stretch by altering their adhesion, proliferation, locomotion, morphology, and synthetic profile. In order to elucidate the interrelated effects of different mechanical stimuli on cell phenotype in vitro, we have developed a method for culturing mammalian cells in a two-dimensional environment at a wide range of combined levels of substrate stiffness and dynamic stretch. Polyacrylamide gels were covalently bonded to flexible silicone culture plates and coated with monomeric collagen for cell adhesion. Substrate stiffness was adjusted from relatively soft (G' = 0.3 kPa) to …

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An Alternative Current Control Approach For Dip Transfer Gmaw, Gary Dean, Dominic Cuiuri, John Norrish, Christopher Cook Dec 2015

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

Dominic Cuiuri

No abstract provided.

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A Framework For Control Of Robots With Energy Regeneration, Hanz Richter Dec 2015

A Framework For Control Of Robots With Energy Regeneration, Hanz Richter

Hanz Richter

This paper focuses on robot control problems where energy regeneration is an explicit consideration, and it proposes a methodology for modeling and control design of regenerative motion control systems. The generic model consists of a robotic manipulator where some joints are actively controlled and the remaining joints are energetically self-contained and semi-actively controlled. The model can capture various electromechanical and hydraulic actuator configurations for industrial robots and powered human-assist devices. The basic control approach consists of three steps. First, a virtual control design is conducted by any suitable means. Then, virtual control inputs are enacted by a matching law for …

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A New Approach To Controlled Short Circuit Transfer In Gmaw, John Norrish, Gary Dean, Dominic Cuiuri, Christopher Cook Dec 2015

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

Dominic Cuiuri

No abstract provided.

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Thermodynamic Method For Prediction Of Surfactant Modified Oil Droplet Contact Angle, Samuel Morton, David Keffer, R. Counce, D. Depaoli, M. Hu Dec 2015

Thermodynamic Method For Prediction Of Surfactant Modified Oil Droplet Contact Angle, Samuel Morton, David Keffer, R. Counce, D. Depaoli, M. Hu

Samuel A Morton

A model applying surfactant self-assembly theory and classical thermodynamics has been developed to aid in the prediction of solid surface cleaning by aqueous surfactant solutions. Information gained from a combination of surfactant self-assembly behavior and cleaning system parameters, such as oil species, surfactant type, temperature, alkalinity, and solid surface type has been shown to provide insight into surface cleaning. The model combines minimization of free energy, pertinent component distribution mechanisms, and surfactant self-assembly processes to provide a methodology for the predicting of oil droplet contact angles. Such predictive capabilities will allow for the development of beneficial environmental and economic changes …

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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 Dec 2015

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 …

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A Flexible Approach To On-Site Power Filtering And Supply Backup Using High Capacity High Temperature Smes For Maximum Equipment Utility, Dominic Cuiuri, Jeffrey Moscrop, Christopher Cook Dec 2015

A Flexible Approach To On-Site Power Filtering And Supply Backup Using High Capacity High Temperature Smes For Maximum Equipment Utility, Dominic Cuiuri, Jeffrey Moscrop, Christopher Cook

Dominic Cuiuri

With power systems subject to an ever-increasing variety of load types, power quality remains of concern to both utilities and consumers alike. Some of the most concerning issues to users of sensitive equipment include voltage sags, supply interruption and current harmonics. This paper describes a comprehensive power quality device that can be designed to compensate for harmonic load currents and mains voltage variations in a system, as well as providing mains failure backup for smaller critical system loads. The design process described integrates high capacity high temperature Superconducting Magnetic Energy Storage (SMES) technology with Active Power Filter (APF) switching technology …

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Magnetic Transitions In Disordered Gdal2, D. Williams, Paul Shand, Thomas Pekarek, Ralph Skomski, Valeri Petkov, Diandra Leslie-Pelecky Dec 2015

Magnetic Transitions In Disordered Gdal2, D. Williams, Paul Shand, Thomas Pekarek, Ralph Skomski, Valeri Petkov, Diandra Leslie-Pelecky

Thomas M. Pekarek

The role of disorder in magnetic ordering transitions is investigated using mechanically milled GdAl2. Crystalline GdAl2 is a ferromagnet while amorphous GdAl2 is a spin glass. Nanostructured GdAl2 shows a paramagnetic-to-ferromagnetic transition and glassy behavior, with the temperature and magnitude of each transition dependent on the degree and type of disorder. Disorder is parametrized by a Gaussian distribution of Curie temperatures TC with mean TC and breadth Δ TC. A nonzero coercivity is observed at temperatures more than 20 K above the highest TC of any known Gd-Al phase; however, the coercivity decreases with decreasing temperature over the same temperature …

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Fgf2-Induced Effects On Transcriptome Associated With Regeneration Competence In Adult Human Fibroblasts, Olga Kashpur, David Lapointe, Sakthikumar Ambady, Elizabeth Ryder, Tanja Dominko Dec 2015

Fgf2-Induced Effects On Transcriptome Associated With Regeneration Competence In Adult Human Fibroblasts, Olga Kashpur, David Lapointe, Sakthikumar Ambady, Elizabeth Ryder, Tanja Dominko

Sakthikumar Ambady

BACKGROUND: Adult human fibroblasts grown in low oxygen and with FGF2 supplementation have the capacity to tip the healing outcome of skeletal muscle injury - by favoring regeneration response in vivo over scar formation. Here, we compare the transcriptomes of control adult human dermal fibroblasts and induced regeneration-competent (iRC) fibroblasts to identify transcriptional changes that may be related to their regeneration competence. RESULTS: We identified a unique gene-expression profile that characterizes FGF2-induced iRC fibroblast phenotype. Significantly differentially expressed genes due to FGF2 treatment were identified and analyzed to determine overrepresented Gene Ontology terms. Genes belonging to extracellular matrix components, adhesion …

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Droplet Size Regulation In The Short Circuit Gmaw Process Using A Controlled Current Waveform, Dominic Cuiuri, John Norrish, Christopher Cook Dec 2015

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 …

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Discovering Methodologies For Integrated Product Design, Cirrus Shakeri, David Brown, Mohammad Noori Dec 2015

Discovering Methodologies For Integrated Product Design, Cirrus Shakeri, David Brown, Mohammad Noori

David C. Brown

The current methodologies for multi-disciplinary product design are based on compromising between different disciplines rather than integrating them. These methodologies do not use a systematic and holistic approach to the problem of multi-disciplinary design and thus are piecemeal rather than comprehensive. This paper presents a new approach to producing design methodologies for integration of the different disciplines in the design process. A multi-agent system has been developed that designs a 2-DOF robot arm by incorporating five proposed strategies for integration between disciplines. Design methodologies are extracted by tracking the system and generalizing the traces that are produced. The results show …

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Miab Welding Of Oil And Gas Pipelines, L. Fletcher, Gabriel Stecher, Cec Stubbs, John Norrish, Dominic Cuiuri, Jeffrey Moscrop Dec 2015

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

Dominic Cuiuri

No abstract provided.

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Verstatile Welding Power Source Controller For Research And Product Development, Dominic Cuiuri, John Norrish Dec 2015

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.

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