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  • 201.
    Andersson, Tommy
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Lindell, Erik
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Kartläggning av begränsande faktorer vid fellokalisering med pulsekometod på mellanspänningskablar2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    As the medium voltage network cables in Sweden is buried down in the earth, the demand of fault localization expertise increases. To keep downtimes in the network short, the importance of effective fault localization is necessary. This work is aimed to map and visualize limiting factors within fault localization with focus on the TDR -

    Time Domain Reflectometry. This work is a collaboration with Vattenfall Eldistribution AB.

    Problems with fault localization on medium voltage cables with the TDR have been detected. A multiple factors are contributing to this problem. The results of this study show that the cable construction is a significant part in which extent the TDR can be used. The report are also accounting for basic information about construction and types.

    The mapping also illustrates water treeing and how it affects cables in a negative way. Visualization of what causes water treeing and several actions such as triple extrusion, jacket testing and insulation testing is included in the essay. Further information about fault types, cable types, cable generations, instrument types and method types is given. All of them are affecting factors within the area of fault localization.

    Documentation is highly important for a successful fault localization procedure, which is clarified in the report. Besides documentation the cable condition and the influence on it affecting the result of fault localization is stated.

    A number of measuring methods and instruments are available to use when fault localization and testing are occurring. Every instrument has their own advantages and disadvantages. They also have their own respective area of usage. The basic principle of TDR is studied and explained accordingly. The other measuring methods, which are used in fault localization and testing, are shown more generally

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  • 202.
    Andlovic, Mihael
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    How real-world IP-distribution affects load balancing2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This essay looks at how IP addresses on the last octet are distributed and how they are balanced by different load balancer algorithms. We collected the data from a data center in Sweden to get real data. The IP addresses we collected were used with a load balancer using IP source algorithms. We used 4 different algorithms in different scenarios: the entire IP address, the first 3 octets, and the last octet with and without hash between two to five links/servers. The results were that the efficiency of the algorithm depends on the setup that is being used. Each of these algorithms did not have an even distribution, when comparing between two to five links/servers. The best overall distribution that did not have any weaknesses compared to the other algorithms was Nginx that uses the Bob Jenkins hash algorithm.

  • 203.
    Andreassen, Håkon
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Fallstudie av tidsförluster inom kemisk industri2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis has been carried out with the purpose of streamlining production at Nouryons EMU factory in Stenungsund. The goal has been to map and identify the root causes to nonvalue-creating time in the production. The work began with a literature study where relevant theory and information was taken from books, articles and websites. Subsequently, a case study was conducted which is partly based on observations and unstructured interviews, but also on data from Nouryons internal reporting system OAM portal. The work has been able to establish that there are five categories that together account for 54% of the lost production time in the factory. An analysis of these revealed, however, that data should be treated with some caution. During the work, it has been established that 12% of the events under the category Quality analysis in reactor stage two are probably incorrectly categorized. A suggestion for improvement is for Nouryon to map these events, which can possibly be turned into two separate categories. Here, this project can form the basis forfurther development of the OAM portal.

  • 204.
    Andreasson, Johan
    et al.
    University West, Department of Engineering Science.
    Fåll, Fabian
    University West, Department of Engineering Science.
    Krav på kundägd anslutningspunkt med produktionsanläggning2023Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Vattenfall Eldistribution AB is one of Sweden's largest grid owners and aims to make Sweden fossil-free within one generation. In order to cover Sweden's electrical energy needs in a fossil-free way, more renewable production plants are required. One of the production plants that is growing the most right now is solar cell plants. Swedish standards have rules for how production plants must be designed. Among other things, there are requirements on how the manual disconnection of the solar cells should work and that there must be a circuit breaker that can disconnect the entire production plant, also called a production circuit breaker. Due to different interpretations, this circuit breaker has been allowed to be placed in different ways, but now Vattenfall Eldistribution AB wants to use this work to develop a standardized way to install the production circuit breaker. Therefore, the main goal of the work has been to produce guidelines for how customers of Vattenfall Eldistribution AB should place the production circuit breaker in the plant.

    The work presents a comprehensive description of what a solar cell installation might look like and how the amount of these facilities have changed in Sweden. As the statistics show that the number of production facilities increases every year, it is important that there are clearer guidelines from grid owners. In addition, how Vattenfall Eldistribution AB handles a request to install solar panels has been investigated. Through calculations of the electricity network, it is determined how the connection of the production plant will be carried out.

    In order to achieve a result, it was necessary to gather information from several sources. Vattenfall Eldistribution AB shared what was important to them and how they would like the installations to be designed. As a supplement to Vattenfall Eldistribution AB's opinion, relevant standards and regulations were examined. In order to further justify the placement to customers, consideration was also given to the fire department's requests for solar cell installations. Based on the information from all sources, guidelines were created. These guidelines present different locations of the production circuit breaker. For each location the advantages and disadvantages are described.

    The conclusions of the work are that the production circuit breaker needs to be placed outdoors, either on the facade of the building or alternatively in the meter cabinet if it is outdoors. In addition to the location of the production circuit breaker, the inverter for the plant also needs to meet the requirements set by regulations, which is done by choosing an inverter that is on the list of "Rikta Rätt" from Swedenergy.

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  • 205.
    Andréasson, Kim
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Hagberg, Daniel
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Undersökning av iBeaconannonsering via smartphoneapplikation: Objective c och ASP.NET2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This degree project is performed together with the company Sigma in relation with the education Datateknisk Systemutveckling at Högskolan Väst in Trollhättan. The purpose of this project is to examine the new technology iBeacon and study if it is to prefer over simi-lar technologies when developing a system to use for advertisement. To accomplish this, a smartphone application is developed aswell as an administration interface, to be able to perform a user test of the product with a random selection of people.

    The goal with the project is to develop a working product that can be tested and used for the examination of the hypothesis. This report explains how the project is performed and in the end, the result that the user test shows is discussed.

  • 206.
    Anselmby, Ellen
    University West, Department of Engineering Science.
    Radio Remote Control in Industry 4.02022Independent thesis Basic level (professional degree), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    After a number of industrial revolutions, the industry is facing a new revolution, the 4th industrial revolution, also called Industry 4.0. The revolution referring to emerging technologies such as Internet of Things, Big data, Digital Twins, Cyber-physical System among others.

    Tele-Radio i Lysekil AB is a company that is develop, produce and distribute radio remote controls. These remote controls are wireless and is used in an industrial environment. Operators that use this as a tool can stand from a safe distance, observe the action, and control the process with the remote.

    This thesis project focuses on researching how radio remote control system can be utilised to create a safe and flexible workplace in an Industry 4.0 environment. How should companies, developing products adapt and integrate to the industry that is implementing Industry 4.0 to their process, how will the workplace and organisation change?

    The Industry 4.0 will change the way of working. The need for operators to adjust and develop their skills and knowledge to properly manage the new digital solutions and technology will likely be the source of human resistance.

    The need for a radio-controlled remote control system will continue to exist. In a situation where large amounts of data are available, and the operator is carrying a device that allows him or her to manage the environment, the need and capacity to respond to.

  • 207.
    Antoine, Galluet
    University West, Department of Engineering Science, Division of Automation Systems.
    Kinect to control robot: New ways to interact with robots2015Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The main goal of the thesis is to create a way to interact with a ABB robot by using a Kinect.The focus will be put on making the robot mimicking the user's arm movement. But otherway like voice control will be investigated.Two main part of the work are developed in this report. The first one is the software aroundthe Kinect to get the body data. The software developed provides the user a visual feedbackon what the Kinect see and allows him to choose what mode he wants to use. Two mainmode are implemented. A mimicking one which makes the robot mimicking the chosen armand a moving object mode which tell the robot to go to the user's position and set the toolas the user hand state.When all the data are gathered, they are sent to the robot using an IP socket and predefinedmessage to give him the desired order.

  • 208.
    Antonsen, Cristoffer
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Asplund, Oscar
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Guide för projektering inom högspänning2020Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is written with the purpose of forming a guide in the area of high voltage project planning, requested by Vattenfall Eldistribution AB. Another purpose with the guide is too introduce new employees to project planning. The material will be available at the company's shared servers. The thesis also contains profound theory about phase to ground capacitance and the fault current to earth through the previous mentioned capacitance.

    Literature studies and interviews was used to complete the creation of this guide. The guide was tested using fictitious powerlines in the calculation program Netbas for the purpose to ensure that the guide was user-friendly and worked as intended. The software program used for calculations is Netbas which is a master data system where the power grid companies store their net image and future buildouts. The interviews were used to give a picture of how the work structure of the department is today and what challenges exist within project planning.

    The work is done for the grid connection department and the roles that exist is connection- engineers and – technicians. The most commonly tasks at the department are customer initiated new connections, reconnections and extension of existing costumer subscription.

    The developed guide consists of ten steps which has its own chapter with instructions to perform a high voltage project planning. To give the user an overview of the guide and save time, a flow chart was made where the necessary steps are shown to make the work smoother. Some of the steps are more theory based to give the user a deeper understanding about the subject and some of the steps consist of instructions for the user to follow. The design of the guide was made in PowerPoint and zoom functions were used to enable a e-learning feeling.

    Another conclusion from the work is that is deals mostly with normal cases and could in the future be extended in areas such as parallel cables and connections of production facilities such as solar parks.

  • 209.
    Aragon Polanco, Gonzalo Eduardo
    University West, Department of Engineering Science.
    Inspection of welding electrodes using computer vision2022Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The use of computational methods to perform inspection tasks in the modern industry has increased in the last years, the fast response and repeatability are the key factor to define a standard in quality control. The visual inspection of components was in charge of highly skilled operators who were searching for defects or failures, but the complexity of the inspection triggered the necessity to migrate to a computational approach. This computer inspection system is composed of the hardware and the algorithm. The hardware includes the lighting and the camera, meanwhile, the algorithm works directly with the failure identification.

    In the welding industry, the SMAW (Shielded Metal Arc Welding) consists of using an electrode stick that is melted for the heat produced from an electro-voltaic arc between the electrode and the surface of the base metal. The quality of the welding depends on the quality of the electrode, that is why this project is focused on the visual inspection of the electrodes. The visual defects that compromise the welding quality can be fixed in two categories: the shape of the electrode and the texture of the surface. These two categories contemplate the existence of cracks, porosity and extrusion defects.

    The method which delivered the best results (94% of accuracy, 92% of repeatability) used a dark background, colour segmentation, image pre-processing (border enhancement), YOLO network for deep learning and image entropy performed in MATLAB. Additionally, the detection method allows identifying the position of the defects, their size and their type.The location of the defect is determined thanks to the division of the electrodes into smaller parts, if a failure is detected in one or more of them it is possible to know the position and the size of the defect. Meanwhile, the type of defect is the result of analysing the deep learning and entropy results. The collected failure data is presented in the inspection report, which has the potential to become a tool that could modify and enhance the manufacturing processes.

  • 210.
    Aranke, Omkar
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Effect of spray parameters on micro-structure and lifetime of suspension plasma sprayed thermal barrier coat-ings2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Fabrication of Thermal Barrier Coatings (TBCs) with higher lifetime and relatively cheaper processes is of particular interest for gas turbine applications. Suspension Plasma Spray (SPS) is capable of producing coatings with porous columnar structure, and it is also a much cheaper process compared to the conventionally used Electron Beam Physical Vapour Dep-osition (EB-PVD). Although TBCs fabricated using SPS have lower thermal conductivity as compared to other commonly used processes, they are still not commercialized due to their poor lifetime expectancy.

    Lifetime of TBCs is highly influenced by the top coat microstructure. The objective of this work was to study and evaluate the top coat microstructure produced using axial SPS with different process parameters. 8 wt. % Yttria Stabilized Zirconia (YSZ) suspension with 25 % solid load in ethanol was used to spray the top coat. The bond coat was deposited on Has-telloy-X substrates using a NiCoCrAlY powder by High Velocity Air Fuel (HVAF) spray with same process parameters. Influence of the microstructure on lifetime of the coatings was of particular interest in this work. The coating microstructure was analysed using Scanning Electron Microscope (SEM) and it was observed that axial SPS is capable of producing TBCs with varied top coat microstructure from highly porous to densely packed columnar microstructure. The lifetime of the coatings was determined by Thermal Cyclic Fatigue (TCF) testing and Burner Rig Testing (BRT). Porosity and Thermal conductivity of the coat-ings was determined by Image Analysis and Laser Flash Analysis (LFA) respectively.

    From the results obtained, it can be concluded that axial SPS could be a promising method of producing TBCs with low thermal conductivity & high lifetime for high temperature gas turbine applications.

  • 211.
    Aranke, Omkar
    et al.
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Algenaid, Wael
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Awe, Samuel
    R and D Department, Automotive Components Floby AB, Floby, 52151, Sweden.
    Joshi, Shrikant V.
    University West, Department of Engineering Science, Research Enviroment Production Technology West.
    Coatings for automotive gray cast iron brake discs: A review2019In: Coatings, ISSN 2079-6412, Vol. 9, no 9, article id 552Article in journal (Refereed)
    Abstract [en]

    Gray cast iron (GCI) is a popular automotive brake disc material by virtue of its high melting point as well as excellent heat storage and damping capability. GCI is also attractive because of its good castability and machinability, combined with its cost-effectiveness. Although several lightweight alloys have been explored as alternatives in an attempt to achieve weight reduction, their widespread use has been limited by low melting point and high inherent costs. Therefore, GCI is still the preferred material for brake discs due to its robust performance. However, poor corrosion resistance and excessive wear of brake disc material during service continue to be areas of concern, with the latter leading to brake emissions in the form of dust and particulate matter that have adverse effects on human health. With the exhaust emission norms becoming increasingly stringent, it is important to address the problem of brake disc wear without compromising the braking performance of the material. Surface treatment of GCI brake discs in the form of a suitable coating represents a promising solution to this problem. This paper reviews the different coating technologies and materials that have been traditionally used and examines the prospects of some emergent thermal spray technologies, along with the industrial implications of adopting them for brake disc applications. © 2019 by the authors.

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  • 212.
    Aranke, Omkar
    et al.
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Gupta, Mohit Kumar
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Markocsan, Nicolaie
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Li, Xin-Hai
    Siemens Industrial Turbomachinery AB, Finspång, Sweden.
    Kjellman, Björn
    GKN Aerospace Sweden AB, Trollhättan, Sweden.
    Microstructural Evolution and Sintering of Suspension Plasma-Sprayed Columnar Thermal Barrier Coatings2019In: Journal of thermal spray technology (Print), ISSN 1059-9630, E-ISSN 1544-1016, Vol. 28, no 1-2, p. 198-211Article in journal (Refereed)
    Abstract [en]

    Suspension plasma spray (SPS) is capable of producing coatings with porous columnar structure, and it is also a much cheaper process compared to the conventionally used electron beam physical vapor deposition (EB-PVD). Although TBCs with a columnar microstructure that are fabricated using SPS have typically lower thermal conductivity than EB-PVD, they are used sparingly in the aerospace industry due to their lower fracture toughness and limited lifetime expectancy. Lifetime of TBCs is highly influenced by the topcoat microstructure. The objective of this work was to study the TBCs produced using axial SPS with different process parameters. Influence of the microstructure on lifetime of the coatings was of particular interest, and it was determined by thermal cyclic fatigue testing. The effect of sintering on microstructure of the coatings exposed to high temperatures was also investigated. Porosity measurements were taken using image analysis technique, and thermal conductivity of the coatings was determined by laser flash analysis. The results show that axial SPS is a promising method of producing TBCs having various microstructures with good lifetime. Changes in microstructure of topcoat due to sintering were seen evidently in porous coatings, whereas dense topcoats showed good resistance against sintering.

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  • 213.
    Araya, Abel Russom
    et al.
    University West, Department of Engineering Science.
    Aden, Mohamud Abdullahi
    University West, Department of Engineering Science.
    Best Practice enligt ramverket ITIL: en studie om ITIL i praktiken2022Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    We conduct dissertations on the investigation of routines, models and systems on how companies and organizations should use IT operations. One of the systems is ITIL (Information Technology Infrastructure Library). As we do research on, how it works in practice in the workplace and whether there is a difference between companies. There are others such as Devops (Software development and IT operation), Agil, Scrum, ISO / IEC standards, Practical guide for policy analysis etc.

    Today, there are many different established methods, standards, models and routines for how companies and organizations should use IT operations. There are many systems that are process oriented for how companies and organizations conduct IT operations and support. One of the systems is ITIL (Information Technology Infrastructure Library). ITIL consists of five books that together form a framework for how to conduct management, operation and support in a process oriented manner.

    This thesis is based on a study of how ITIL is structured and how relevant it is today through research / interviews with various organizations that have adopted the framework specifically for ITIL's sub-processes problem management, access management and incident management. If it is experienced positively and is adaptable where previous surveys show that the implementation of ITIL has not fully worked on operations.

    We have investigated and focused more closely on some of ITIL's sub-processes Access, Problem and Incident Management. The ITIL framework that a collection of best practices can use during the implementation of IT operations. According to the results, ITIL has quite a large impact on the various operations. The effect it has on the operations is that after adapting this framework, the operations could have a better, more efficient and structured way of working.

    The framework is useful and helpful for the businesses as they do not have to invent their own methods or processes to get started, but they have the framework as method support, and they can work effectively. ITIL is too complex, and the organizations cannot make full use of the framework and more knowledge and time is needed to be able to complete the implementation of the framework, but this is also a resource issue for many organizations. However, you have your own solutions for the parts that you have not chosen to implement from the framework, which benefits the organization based on their needs. It is simply considered and said that we are satisfied with these parts and do not need to bother our staff or the business with implementing other parts.

  • 214.
    Arbat, Akshay
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Thermal spray coatings on additive manufacturing parts: Coating deposition and investigation2021Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Additive manufacturing (AM) is gaining popularity due to the increased demands for the production of complex geometries and difficult-to-machine components. The increasing trend of AM focuses more on high-temperature applications in the field of aerospace, automotive, power generation, etc. In high-temperature applications, the material often needs to be resistant to oxidation and corrosion. Alloy 718 is a promising material because of its better properties at elevated temperatures. Recently alloy 718 based parts have been manufactured by the electron beam powder bed fusion (EBPBF) process. Different post-processes such as shot peening (SP) and hot isostatic pressing (HIP) were used to improve the properties of the AM-built samples. As an alternative method to post-processing, NiCoCrAlY coating was thermal sprayed on the AM-built samples.

    The present study explores the effect of the different processing methods on the mechanical and functional properties of the coatings . Post-processes help reduce the roughness of AM components due to the peening effect during SP and temperature and pressure during HIP. The shot peening was responsible for increasing the hardness near the coating-substrate interface while HIP reduces the hardness due to grain coarsening and dissolution of strengthening phases. The NiCoCrAlY coating was deposited on the sample by a high-velocity air fuel process. Coated AP, SP3 and HIP samples showed better adhesion strength because of mechanical interlocking between coating and substrate. The coating acts as a protective layer by forming oxide scale (Cr and Al oxides) and helps to protect the substrate from corrosion and oxidation. The shot peening was responsible for reducing the erosion rate in uncoated samples, while the coated sample showed similar behavior.

    The present study explores the effect of post-process on the coating microstructure and other properties. The AM-produced sample does not require post processes before spraying a coating. Thermal spraying on AM parts is beneficial for improving properties. 

  • 215.
    Arbo, Thomas
    University West, Department of Engineering Science, Division of Mathematics, Computer and Surveying Engineering.
    YubiKey: Utvärdering av tvåfaktorsautentisering2019Independent thesis Basic level (professional degree), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    YubiKey is a small hardware method of authentication, designed to authenticate a user on various network-based platforms such as Google, Dropbox, Facebook and Twitter.

    In the first part of this paper, the underlying technology of the YubiKey, such as the one-time password protocol (OTP) and the Universal 2nd Factor standard, is further described, as well as the approach of the tests to examine how practical and secure the method itself is, but also examines its ease of use. These tests were performed on the platforms Google Account, Facebook, Dropbox and Twitter platforms. The YubiKey is also compared to other methods in relation to the phishing, malware, password guessing, man-in-the-middle and shoulder surfing attacks.

    The purpose of the comparison was to see if YubiKey protects against these attacks, compared to other methods, thus investigating its security. A later part presents the results of the tests, but also compares YubiKey with other methods in the market, and examines the recovery of a stolen och lost Yubikey. These tests show the simplicity of the method, its ease of use and how practical the method is.

    The comparison clearly shows that YubiKey is a very safe method, which resists common threats to the user side. The simulation of the recovery process further attests to its ease of use and ease of handling, even with lost or stolen key.

  • 216. Archana, M. S.
    et al.
    Srikanth, Vvss
    Joshi, Shrikant. V.
    Joardar, J.
    Influence of applied pressure during field-assisted sintering of Ti(C,N)-WC-FeAl based nanocomposite2015In: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 41, no 2, p. 1986-1993Article in journal (Refereed)
    Abstract [en]

    Ti(C,N)-WC-FeAl based nanocomposites are processed by field-assisted sintering at 1500 degrees C. The phase and microstructural evolution during the process under the influence of different applied pressures of 30, 50 and 100 MPa are studied using x-ray diffraction and scanning electron microscopy. Lattice parameters of (Ti,W)(C,N) solid solution and binder phases after sintering are found to vary with applied pressure. The nanocomposite grains are observed to possess a core-rim microstructure. Microstructural variations in terms of type, size and fraction of "corerim" structure as a function of applied pressure are investigated. The hardness and indentation fracture toughness values are in the range of 17.6-18.4 GPa and 5.9-6.8 MPa root m, respectively. These values are comparable with those reported for Ti(C,N)-based composites with metal binder. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

  • 217.
    Ardstål, Linus
    et al.
    University West, Department of Engineering Science.
    Starborg, Mikael
    University West, Department of Engineering Science.
    Oskärmad vs skärmad nätverkskabel; Hur stor skillnad gör det egentligen?2023Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [sv]

    UTP (Unshielded Twisted Pair) och STP (Shielded Twisted Pair) är två typer av kablar som används för att överföra data över ett nätverk. Båda typerna av kablar används för liknande ändamål, men de har vissa skillnader som kan vara betydande i vissa distributions scenarier. I småskaliga distributioner kanske UTP- och STP-kablar inte har någon signifikant skillnad i prestanda eller tillförlitlighet. Detta beror på att kablarna i ett litet nätverk vanligtvis inte behövs för att överföra data över långa avstånd eller i miljöer med höga nivåer av Electromagnetic Interference (EMI).UTP-kablar består av par med tvinnade ledningar, utan skärmning runt ledningarna. De är vanligtvis billigare än STP-kablar och enklare att installera eftersom de är lättare och mer flexibla. UTP-kablar används ofta i småskaliga distributioner som hem, små kontor och klassrum. I småskaliga distributioner kanske fördelarna med STP-kablar inte är nödvändiga, eftersom avståndet över vilket kablarna behöver överföra data vanligtvis är kort och det finns mindre risk för störningar. Dessutom kan UTP-kablar ge tillräcklig prestanda och tillförlitlighet för de flesta småskaliga nätverk. Vår metod för att introducera störning är att vira en lång UTP-kabel runt många strömkablar och tillhörande kopplad utrustning samt runt en stark strömkälla, en mikrovågsugn, för att se om dessa representationer av lågstörningsmiljöer är tillräckligt för att störa trafiken, trafiken mäts med iperf3 och Ubuntus egna felrapportering.Resultatet blev att nej, dessa scenarion var otillräckliga för att skapa någon nämnvärd störning av trafiken, mer efterforskning behövs och ännu starkare källor av störning bör tillämpas för att kunna se om det blir någon påverkan på trafiken med dessa mätmetoder.Detta innebär att i alla vardagliga scenarion är skärmad kabel helt överflödig och bör undvikas, en besparing både ekonomiskt och resursmässigt.

  • 218. Arezoomande, Daniel
    Anslutning av två vindkraftverk till befintligt nät2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis was conducted at University West in Trollhättan and Kungälv Energi AB in Kungälv. Being owner of an electrical grid, Kungälv Energi AB has the responsibility to check if the electrical grid needs to be reinforced when connecting new electricity generation facilities such as two new wind turbines. This thesis mission is to examine how the voltage quality might be affected by the connection of the wind turbines and give suggestions on how to solve eventual problems. Several alternatives will be examined for how the cables between the wind turbines and the power grid should be placed. One cost calculation will be presented. The voltage quality calculations are done through the guidelines from AMP, Anslutning av Mindre Produktionsanläggningar. Because the provider of the wind turbines has yet to be decided, necessary data has been taken from the previously connected wind turbine in Skåreby, "Vindrosen". The cost calculations are done with the help of EBR, ElByggnadsRationalisering. The cable dimension alternatives that are presented are based on costs and long term planning. These dimensions are 95mm2 and 240 (underground transmission line)- alt. 241mm2 (overhead transmission line). The thesis also includes suggestions for alternative dimensioning of the currently placed power grid at the point of interconnection for the wind turbines. All presented alternatives of the dimensioning for the cables are solely 24kV in accordance with the rest of the power grid to avoid unnecessarily high costs. It is recommended that Kungälv Energi AB does not connect the wind turbines before more thorough calculations are made in conjunction with eventual harmonic distortion measurements. This is because the equations AMP refers to are deemed imprecise due to some parameters such as cable capacitance have not been taken into consideration. It is recommended that, during the negotiations of the new wind turbines, Kungälv Energi AB limits the maximum current harmonic distortions that the wind turbine produces.

  • 219.
    Arezoomande, Daniel
    University West, Department of Engineering Science.
    Condition based maintenance of electrical motors in the mining industry2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This project aims to present a condition-based maintenance algorithm for common motor faults on three-phase induction motors in the mining industry through the use of the E300 overload relay. To fulfil this aim establishing what motor faults are common and which ones are suitable for detection based on electrical signal monitoring was explored. Through investigative research no distinction between common motor faults in general and those in the mining industry was discovered. A number of electrical signals candidates were chosen based on limited available research and consulting with experts in the field. To test these signals a number of phase to phase motor faults were physically simulated on a test rig. The resulting trend of the signals were saved and comparatively analyzed with a regular mechanical motor overload to find deviations that would indicate the fault has occurred.

    The most useful monitored signal was the current imbalance and the line current measurements. Through monitoring these signals it was concluded that the one phase-pair fault and the two phase-pair fault could be discovered by monitoring real-time values. The three phase-pair fault could not be discovered by monitoring the real-time values, but can be found trough historical trends of the line currents and current imbalance. 

    A condition-based maintenance algorithm was proposed utilizing the monitored electrical signals to create trends that can be tied to alarms. A general motor health index that would use the monitored signals to easily convey the health of the motor is proposed. A faceplate design for the Panelview 5510 was designed showing the trends of the various electrical signals that would be used by an operator in the field.

  • 220.
    Arfvidsson, G. F.
    et al.
    School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm (SWE).
    Ljungdahl Eriksson, Martin
    University West, School of Business, Economics and IT, Division of Media and Design.
    Lidbo, H.
    Rumtiden, Stockholm (SWE).
    Falkenberg, K.
    School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology.
    Design Considerations for Short Alerts and Notification Sounds in a Retail Environment2021In: Proceedings of the Sound and Music Computing Conferences, Sound and Music Computing Network , 2021, Vol. 2021-June, p. 261-267Conference paper (Other academic)
    Abstract [en]

    The design and noticeability of alert sounds have been widely researched and reported, and not least, notification sounds are ubiquitous in both software and hardware product development. In an ongoing research project concerning the retail industry, we aim at designing short alert sounds that only grab attention from one group of customers, while others do not register the alerts: this particular aspect has to our knowledge not yet been studied. To establish design guidelines for such alert sounds, we conducted an experiment where test subjects would experience ordinary shopping activity including background music and an ambient soundscape in a virtual reality clothing store, but with added alert sounds. We tested, specifically, six differently designed sound alerts belonging to two classes: contextual-specific congruent sounds, and incongruent sounds that did not fit the sonic context. The results disproved our assumptions that incongruent sounds would outperform the congruent and thus in the context more anticipated sounds. The findings suggest that alert sounds can be designed with subtlety and still be noticeable and that customers will not necessarily be annoyed. We present here a first approach towards design guidelines for short alert sounds in a shop environment. Copyright: © 2021 the Authors.

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  • 221.
    Arghavan Shahlaei, Charlotte
    et al.
    University West, School of Business, Economics and IT, Divison of Informatics.
    Kazan, Erol
    IT University of Copenhagen, Copenhagen (DNK).
    Digitizing Products towards Platforms: the Case of Vehicle Motion System2020In: Making Digital Inclusive: Blending the Local and the Global, Association for Information Systems, 2020, article id 2557Conference paper (Other academic)
    Abstract [en]

    The development of digital product platforms is a prevailing trend in many industries. As firms incorporate digital technologies into established product categories, they need to manage tensions on multiple organizational layers including strategy, technology and structure. Recent findings suggest that tensions are most likely to be managed by creating resource and coordination flexibility. This paper reports a longitudinal case study of developing a digital product platform. By drawing on organizational ambidexterity theory, we identify four mechanisms—re-scripting, centralizing-re-directing and decoupling—through which the firm creates resource and coordination flexibility. The resulting resource and coordination flexibility in turn lead to the transformation of the firm’s strategy, technology and internal structure. The contribution of this study is in adopting an internal perspective and a bottom-up approach which help to theorize the evolution of digitized products into digital product platforms in an emergent way.

  • 222.
    Ariaseta, Achmad
    et al.
    University West, Department of Engineering Science, Division of Welding Technology. Department of Metallurgical Engineering, Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (IDN).
    Khan, Abdul Khaliq
    Manitoba Institute for Materials, University of Manitoba, Winnipeg (CAN).
    Andersson, Joel
    University West, Department of Engineering Science, Division of Welding Technology.
    Ojo, Olanrewaju
    Department of Mechanical Engineering, University of Manitoba, Winnipeg (CAN).
    Microstructural study of keyhole TIG welded nickel-based superalloy G272023In: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 204, article id 113178Article in journal (Refereed)
    Abstract [en]

    The weld fusion zone (FZ) microstructure obtained after keyhole tungsten inert gas welding and post-weld solution heat treatments (PWSHTs) of a new nickel (Ni)-based superalloy called G27 is studied, and the grain growth behavior in the base material (BM) during PWSHTs is characterized. Microsegregation-induced interdendritic microconstituents in the FZ of as-welded G27 are identified by analytical (scanning) transmission electron microscopy ((S)TEM) as niobium (Nb)-rich MC carbides, Nb-rich Laves eutectic constituents, γ’ and η phases. The Laves eutectics are generally considered brittle and can adversely affect the mechanical properties of the weldment; thus, an hour PWSHTs were performed at 954 °C–1060 °C to eliminate the γ/Laves eutectics. PWSHT up to 1010 °C results in only partial removal of Laves eutectics with an excessive formation of η phase surrounding the Laves phase. Complete dissolution of Laves eutectics with no η phase formation is achieved after a PWSHT is performed at 1060 °C. Relative to INCONEL® alloy 718, the complete elimination of the γ/Laves eutectic constituents in the FZ of G27 through a PWSHT was proven to be achieved without causing excessive grain growth in the BM, which could be due to the pinning effect of the fine molybdenum (Mo)-rich precipitates, that are formed during solution heat treatment and identified as hexagonal close-packed phase particles through extensive (S)TEM analyses.

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  • 223.
    Ariaseta, Achmad
    et al.
    University West, Department of Engineering Science, Division of Welding Technology.
    Pick, Dario
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Andersson, Joel
    University West, Department of Engineering Science, Division of Welding Technology.
    Ojo, Olanrewaju
    Department of Mechanical Engineering, University of Manitoba, Winnipeg (CAN).
    Keyhole TIG Welding of New Co-Lean Nickel-Based Superalloy G272023In: Proceedings of the 10th International Symposium on Superalloy 718 and Derivatives / [ed] Eric A. Ott, Joel Andersson, Chantal Sudbrack, Zhongnan Bi, Kevin Bockenstedt, Ian Dempster, Michael Fahrmann, Paul Jablonski, Michael Kirka, Xingbo Liu, Daisuke Nagahama, Tim Smith, Martin Stockinger, Andrew Wessman, Springer Cham , 2023, p. 807-824Conference paper (Refereed)
    Abstract [en]

    The influence of keyhole TIG (K-TIG) welding parameters on the weld geometry and defects of a new Co-lean nickel-based superalloy G27 was studied, and the microstructures of the heat-affected zone (HAZ) and fusion zone (FZ) of the K-TIG-welded Alloy G27 were characterized. No cracks are found in the FZ and HAZ. Minimum weld width and face underfill statistically were significantly influenced by travel speed and interaction current*travel speed. Root excess weld metal was only significantly influenced by travel speed. Face excess weld metal was significantly influenced by all the factors, including their interaction. On the other hand, all the factors, including their interaction, did not significantly influence the average pore diameter. In the FZ microstructure, interdendritic microconstituents are identified as (Nb, Ti)C particles and γ/Laves eutectic constituents. In addition, a plate-like phase is observed surrounding the Laves phase, and γʹ precipitates are found to be inhomogeneously precipitated in the FZ. In the partially melted zone (PMZ), (Nb, Ti)C, Laves phase, γʹ precipitates, and plate-like particles are found in the liquated and resolidified regions, suggesting the solidification behavior in PMZ is likely to follow a similar pattern to the one observed in FZ.

  • 224.
    Ariaseta, Achmad
    et al.
    University West, Department of Engineering Science, Division of Welding Technology. Department of Metallurgical Engineering, Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (IDN).
    Pick, Dario
    University West, Department of Engineering Science, Division of Welding Technology.
    Andersson, Joel
    University West, Department of Engineering Science, Division of mechanical engineering.
    Ojo, Olanrewaju
    Department of Mechanical Engineering, University of Manitoba, Winnipeg, MB R3T 5V6 (CAN).
    Study of Pulsed Laser Beam Welding of Nickel-Based Superalloy G272024In: Sustainable Production through Advanced Manufacturing, Intelligent Automation and Work Integrated Learning: Proceedings of the 11th Swedish Production Symposium (SPS2024) / [ed] Joel Andersson, Shrikant Joshi, Lennart Malmsköld, Fabian Hanning, IOS Press , 2024, p. 39-49Chapter in book (Refereed)
    Abstract [en]

    The influence of pulsed laser beam welding (LBW) parameters on the weld geometry and imperfections of a new nickel-based superalloy called G27 was studied by a statistical design of experiment, and the microstructures of the weld fusion zone (FZ) of the pulsed laser beam-welded G27 were characterized. No evidence of cracks is found in the FZ and heat-affected zone (HAZ). Other weld imperfections, such as undercut and underfill, were also hardly observed.

    The pulse factor significantly influenced all the responses, i.e., minimum weld width (Wm), root excess weld metal, and average pore diameter, whereas welding travel speed significantly influenced Wm and root excess weld metal. Power and interaction between pulse frequency*pulse factor were statistically significant in influencing the root excess weld metal and average pore diameter, respectively. The pulse frequency and interactions between power*travel speed, power*pulse factor, power*pulse frequency, travel speed*pulse factor, and travel speed*pulse frequency did not significantly influence any response.

    Microsegregation pattern that occurs during weld solidification leads to the formation of Nb-rich MC carbides and Nb-rich Laves phase as the major secondary phase constituents in the FZ of as-welded G27. The presence of brittle Laves phase requires careful consideration when developing suitable post-weld heat treatment of G27.

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  • 225.
    Ariaseta, Achmad
    et al.
    University West, Department of Engineering Science, Division of Welding Technology. Department of Metallurgical Engineering, Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132, (IDN)).
    Sadeghinia, Nima
    University West, Department of Engineering Science.
    Andersson, Joel
    University West, Department of Engineering Science, Division of Welding Technology.
    Influence Of Keyhole Tig Welding Parameters On Weld Geometry Of Newly-Developed Superalloy Vdm Alloy 7802022In: ICAS PROCEEDINGS33th Congress of the International Council of the Aeronautical SciencesStockholm, Sweden, 2022, Vol. 5, p. 3516-3530Conference paper (Refereed)
    Abstract [en]

    The welding process and the associated control, to a certain degree, have enhanced remarkably in the last decades. One of the recent processes is keyhole TIG (K-TIG) welding, which allows better control and the capability to use lower heat input and higher power density during the welding compared to the conventional one, being essential when joining sophisticated materials utilized in the hot sections of aircraft engines such as nickel-based superalloys. The recent trend in the fabrication of hot sections of aero-engines has been preferably carried out by joining small pieces of superalloys by the welding process instead of casting a single large component due to several benefits, such as lowering the total weight of the components and improving the design flexibility. VDM Alloy 780, a new polycrystalline nickel-based superalloy with service temperature capabilities up to 750 °C, is a promising material to be employed in the fabrication of hot structural parts of an aero-engine. For aerospace manufacturers, producing a superalloy weld bead geometry that meets stringent quality requirements for aerospace applications is crucial. To do so, understanding the influence of welding parameters on weld geometry becomes indispensable, especially when welding a new superalloy using a relatively new welding technique. Hence, in this article, the influence of K-TIG welding parameters on the weld geometry of VDM Alloy 780 has been investigated.

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  • 226.
    Ariaseta, Achmad
    et al.
    University West, Department of Engineering Science, Division of Welding Technology. Department of Metallurgical Engineering, Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Bandung (IDN).
    Sadeghinia, Nima
    University West, Department of Engineering Science.
    Andersson, Joel
    University West, Department of Engineering Science, Division of Welding Technology.
    Ojo, Olanrewaju
    Department of Mechanical Engineering, University of Manitoba, Winnipeg (CAN).
    Keyhole TIG welding of newly developed nickel-based superalloy VDM Alloy 7802023In: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 67, no 1, p. 209-222Article in journal (Refereed)
    Abstract [en]

    The influence of keyhole TIG (K-TIG) welding parameters on the weld geometry and defects of a new nickel-based superalloy VDM Alloy 780 alloy were investigated using a statistical design of experiment, and the microstructures of the heat-affected zone (HAZ) and fusion zone (FZ) of the K-TIG-welded VDM Alloy 780 were characterized. No cracks are found in the FZ and HAZ. Travel speed significantly influences the minimum weld width (Wm), face and root excess weld metal, face underfill, and average pore diameter. Welding current and the interaction current*travel speed significantly influence the face and root excess weld metals, respectively. Interdendritic microconstituents in the FZ are identified as (Nb,Ti)C particles and γ/Laves eutectic constituents based on SEM–EDS analysis. In addition, plate-like precipitates likely to be δ/η phase are observed surrounding the interdendritic Laves eutectics, and γ′ precipitates are found to be inhomogeneously precipitated in the FZ. In the partially melted zone (PMZ), (Nb,Ti)C, Laves phase, and plate-like particles are found in the liquated and resolidified regions. Constitutional liquation of (Nb,Ti)C in HAZ is observed where the liquated (Nb,Ti)C appears to be associated with the γ/Laves eutectic as a resolidified product. 

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  • 227.
    Arkevall, Martin
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Lundgren, Simon
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Återställning av filer: jämförelse av tre gratisverktyg2017Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    To try find a lost file which has been deleted by mistake is probably a common issue for many users. The fact that the recycle bin has been erased too makes the situation more complicated. Or even worse, if a whole partition was reformatted and overwritten. Most users are aware of available support either by contacting a data recovery company or by searching the internet for free tools. Because of the above mentioned common issues, the project has selected three recovery tools to test and compare to find out which tool performs best regarding recovery out of a selection of lost common files. The selection of tools were based from a list with mandatory requirements. The three tools that passed the list was Recuva, Lazesoft and Puran. The results showed variances between the tools where one tool was best in test to recover files back to its original. Another tool performed best when the original size increased after file recovery but the actual data still was functioning properly.

  • 228.
    Aronsson, Andreas
    et al.
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Bäversjö, Jonathan
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    Undersökning av gratis WiFi i Göteborg2014Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    This report examines a number of free WiFi-hotspots that are offered by various companies in central Gothenburg and how they compare to the mobile networks. Traffic, capacity, channel frequencies, signal strength and acceptable use policies were all analyzed and verified.

    The readings showed that the networks were generally not utilized to their full capacity, a probable cause might be the distribution of mobile networks and that channel distribution was with a few exceptions allocated correctly according to 802.11 standards. Acceptable use policies on the networks were implemented by the larger chains but not by the smaller companies

  • 229.
    Arsenault, B.
    et al.
    Industrial Materials Institute, NRC, Boucherville, Que., Canada.
    Gougeon, P.
    University West, Department of Technology, Mathematics and Computer Science.
    Verdier, M.
    Université de Technologie Belfort-Montbéliard, Laboratoire d'Etudes et des Recherches sur les Materiaux les Procedes et les Surfaces (LERMPS).
    Duquesnay, D. L.
    Royal Military College of Canada, Department of Mechanical Engineering.
    Aluminum protective coatings - Fatigue and bond strength properties with respect to surface preparation techniques: Laser ablation, shot peening and grit blasting2006In: Canadian metallurgical quarterly, ISSN 0008-4433, E-ISSN 1879-1395, Vol. 45, no 1, p. 49-58Article in journal (Refereed)
    Abstract [en]

    Aluminum coatings can provide galvanic cathodic protection for several metals and alloys. In order to be a suitable protective solution on structural components, the mechanical integrity must be preserved. In particular, the fatigue properties are a challenge for thermal spray protective coatings on mechanical structures. To address the issue of the fatigue integrity of 7075 aluminum alloy with an arc sprayed protective coating, different surface preparations prior to arc spraying were considered. In the present work, a feasibility study was performed using laser ablation as a surface preparation technique before or during arc spraying of coatings through collaboration between the LERMPS laboratory in France, the National Research Council of Canada and the Royal Military College of Canada. Both fatigue and adhesive properties of aluminum coatings were evaluated in relation to substrate surface preparation techniques including laser ablation (PROTAL® process), grit blasting and shot peening. Results indicate that a combination of key conditions including using nitrogen as the arc spray gas, shot peening and proper laser energy density for ablation provides high fatigue resistance of metallic coated 7075 alloy substrates. Specimens prepared under these conditions show a similar fatigue resistance to uncoated substrates. © Canadian Institute of Mining, Metallurgy and Petroleum.

  • 230.
    Arslan, Metin
    University West, School of Business, Economics and IT, Divison of Informatics.
    Direktmarknadsföring och Cookies: Hur förenklas och förbättras direktmarknadsföring med Cookies2015Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    Organisations are constantly striving after improved products, services and business operations etc. with the help of IT. This means that new approaches in various fieldsemerge. Direct marketing is a phenomenon that has grown significant in recent decades. In Direct marketing is consumer preferences, the results and feedback is vital. A cookie is a text file that is stored on a user's computer to extend the usability for the user. The purpose of this study is to describe how direct marketing can be simplified and improved with Cookies. The study's question is based on the question, how can direct marketing be simplified and improved with the help of Cookies? Based on the study's purpose and question, the analysis consists of these two areas together with the study's results. The study was conducted with a qualitative approach and used an inductive approach. Chain sample principle is a type of convenience sample, which was used during data collection and to increase the study's credibility response validation has been used during the data collection. Empirical material was collected from two respondents who appear anonymously in the results section. These participants are assigned fictitious names, Jakob and Victor. The results are presented on the basis of the information collection process, mapping and analysis process. The text retells in a narrative form and in a woven text to compress the content. The analysis consists of the study's theoretical background and results. With this analysis as a starting point a discussion section is explained in the study. The last chapter in this paper outlines the conclusions from the analysis and discussion.

  • 231.
    Arvidsson, Jakob
    et al.
    University West, Department of Engineering Science.
    Svensson, Pontus
    University West, Department of Engineering Science.
    Analys av varmsprickor i PBF-LB additivt tillverkad Alloy 718 genom varestraint metoden2023Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Alloy 718 is a well-used superalloy within the aerospace industry and other applications where heat resistance is needed. The interest in making more difficult geometries has existed for a long time, and additive manufacturing of the material facilitates that request. When manufacturing with the powder bed fusion laser bed method the size is very limited by the baseplate that is used, which is usually small. Hence, a joining between additive and manufactured Alloy 718 is an alternative to obtain a larger product. The problem that has been discovered is that when the welding process takes place cracks occur within the heat affected zone (HAZ), that’s why a good merging of the alloy is of great interest.

    The goal of this study is to analyse laser welded Alloy 718 manufactured by the PBF-LB method and identify its susceptibility towards cracking, then compare these with previous research, where the same material and manufacturing method was tested with TIG welding. To see which welding process affects the HAZ the least negatively and then draw a conclusion.

    The conclusion was found that the concentrated beam from the laser affects the material in the HAZ less than TIG welding electric charged arc.

    This study provides a new insight into the material’s reaction the heat through joining and helps in decision-making about which welding process should be appropriate for joining the material.

  • 232.
    Arya, Pradyumn Kumar
    et al.
    Department of Mechanical Engineering, IIT Indore, Simrol (IND).
    Jain, Neelesh Kumar
    Department of Mechanical Engineering, IIT Indore, Simrol (IND).
    Sathiaraj, Dan
    Department of Mechanical Engineering, IIT Indore, Simrol (IND).
    Patel, Vivek
    University West, Department of Engineering Science, Division of mechanical engineering.
    Development of high strength and lightweight Ti6Al4V5Cr alloy: Microstructure and mechanical characteristics2024In: Journal of Materials Research and Technology, ISSN 2238-7854, Vol. 28, p. 3526-3540Article in journal (Refereed)
    Abstract [en]

    This article explains development of high strength and lightweight Ti6Al4V5Cr alloy by μ-plasma powder additive manufacturing (μ-PPAM) process for automotive, aerospace, military, dies and moulds, and other similar applications. Microstructure, formation of phases, porosity, microhardness, tensile properties, abrasion resistance, and fracture toughness of multi-layer deposition of Ti6Al4V5Cr alloy are studied and compared with Ti6Al4V alloy. Results reveal that the presence of chromium in Ti6Al4V5Cr alloy refined the grains of its β-Ti and α-Ti phases, increased volume % of β-Ti phase, and promoted formation of its equiaxed grains. It also increased tensile strength, microhardness, abrasion resistance, and fracture toughness of Ti6Al4V5Cr alloy. It enhanced solid solution strengthening and formed higher hardness imparting intermetallic Cr2Ti phase and changed fracture mode to mixed ductile and brittle mode with larger size dimples, cleavage facets, and micropores. But it decreased formation temperature of β-Ti phase and % elongation as compared to Ti6Al4V alloy. Chromium and vanadium content in β-Ti phase of Ti6Al4V5Cr alloy is 7 % and 2.1 % more than its α-Ti phase. This study demonstrates that inclusion of limited amount of chromium content to Ti6Al4V5Cr alloy by μ-PPAM process is very beneficial to enhance microstructure, mechanical properties, crack propagation resistance, and abrasive wear resistance of the Ti6Al4V5Cr alloy. It makes Ti6Al4V5Cr alloy very useful in many commercial applications that require higher strength than Ti6Al4V alloy along with lightweight requirement.

  • 233.
    Aryal, Pradip
    University West, Department of Engineering Science, Division of Welding Technology.
    Gas Metal Arc Melt Pool Modelling: Effect of welding position and electromagnetic force mode2021Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Gas metal arc is a high-efficiency and widely used heat source for metal processing applied predominantly in welding and additive manufacturing. In this study, it was applied to welding. It offers high productivity, low production and investment cost, as well as suffers from some drawbacks such as humping or undercut when welding large parts that are curved and impose changing the orientation of the welding torch along the joint path. Deeper process understanding was therefore sought to mitigate these drawbacks. The difficulty is then the non-lineardependence of the process to the welding parameters and material properties. Besides, visual observation of this process is also difficult. For instance, the elevated temperature and the intense radiative emission from the electric arc, smoke, spatter, as well as the non-transparency of the processed alloy can hinder in-process observation or limit it. Process simulation provides a complementary means to reach process knowledge. It was thus the approach used in this study. For this, a thermo-fluid melt pool model that can predict melting and solidification, track free surface deformation, metal transfer, and coalescence with the melt pool was developed. Two main research questions were identified and addressed.The first one led to studying the effect of the substrate orientation during multilayer welding of a V-groove joint with INVAR and gas metal arc. It was foundthat the force balance in the melt pool changes significantly when the workpieceorientation is changed, resulting in distinct melt flow patterns, melt pool and bead geometries, and in some conditions defect initiation such as humping, undercut, and lack of fusion. As a result, multi-layer welding with flat substrate and downhill welding of a 20◦ inclined substrate are recommended with these process conditions. On the contrary, welding of a side inclined substrate and uphill welding of a 20◦ inclined substrate are not recommended. The second question gave rise to the comparative investigation of the three electromagnetic force models commonly used when modelling a melt pool produced by an electric arc. The underlying modelling assumptions were retrieved and investigated. It was found that each of these three models predicts a different melt flow pattern, different heat convection, melt pool shape, free surface oscillation, and interaction with the transferred metal drops, and thus result in different bead geometry. All these models can be adjusted to predict the penetration depth, however, only the most complete of them is recommended for developing a predictive melt pool model. For this, it is proposed as a future work to improve this model through predicting an electromagnetic force that takes also into account the local deformation of the free surface.

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  • 234.
    Aryal, Pradip
    University West, Department of Engineering Science, Division of Welding Technology.
    Metal fusion using pulsed GasMetal Arc: Melt pool modellingand CFD simulation2023Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Pulsed gas metal arc is a highly efficient technique used in manufacturing processes like welding and additive manufacturing. It offers high productivity and cost benefits but it is also prone to defect formation when process parameters are not properly controlled and optimized. A deeper process understanding can support achieving improved process control and mitigate these potential drawbacks. Nevertheless, there are still several challenges. For instance, the correlation between the input and output process parameters is non-linear and complex due to the multi-physics nature of the process. In addition, the elevated temperature and the intense radiative emission from the arc, along with the smoke, and the non-transparency of metal, make in-process observation challenging. Modelling and simulation offer a complementary approach to gain a deeper process understanding. In this study, a thermo- and fluid dynamics model was developed, focusing on the melt pool and metal deposition, while simplifying the arc to boundary conditions (decoupled approach). This model incorporates various forces and phenomena such as thermocapillary and electromagnetic forces, melting and solidification, and tracking of surface deformation and droplet coalescence.

    In the first part of the thesis, the developed model was applied to investigate the effect of workpiece orientations on the melt pool dynamics and reinforced bead geometry in multi-layer gas metal arc welding of a V-groove joint. The comparison of the predicted fusion zone with macrographs obtained from the experiments showed good qualitative agreement. It was found that the force balance in the melt pool changes significantly when changing the workpiece orientation by as little as 20◦ relative to the flat position. This results in distinct melt flow patterns, melt pool shapes, bead geometries, and in some cases, defect formation such as humping, undercut, and insufficient fusion. It was concluded that to avoid these defects a lower angle range is necessary for multilayer welding with the uphill orientation and side inclination.

    The second part of the thesis focused on analyzing different variants of the model for the electromagnetic force with a decoupled approach. Three commonly used models were compared: (1) the analytical models proposed by Kou and Sun inintegral form, (2) by Tsao and Wu in algebraic form, and (3) the partial differential equations governing the electric and magnetic fields. The comparative investigation was supported by experimental tests that also provided estimates of unknown model parameters and validation data. It was found that the distinct assumptions on which these models rely are not all justified. They resulted inpredicting different melt flow patterns and amplitude of the free surface oscillations, as well as different melt pool shapes and bead geometries. Model (3) is recommended to advance to a predictive melt pool model and was subsequentlyused in the remaining work of the thesis.

    Furthermore, the literature shows that modeling the effect of pulsed arc on the melt pool using a decoupled approach involves various simplifications. Arc pulsation affects energy and force balance in the melt pool through arc heat flux, arc pressure, and electromagnetic force. A systematic investigation of model variants considering pulsing was conducted using previously documented experimental test cases. The results showed that the influence of arc pressure was insignificant in those cases. However, model variants simplifying arc pulsing to a time-averaged effect underestimated the amplitude of the Marangoni flow and downward flow compared to a more comprehensive approach that considered the time dependence of arc pulsation. Thus, it is recommended to use a meltpool model that accounts for the time-dependent arc pulsation, which was also subsequently utilized in the remaining work of the thesis.

    The electromagnetic force models discussed earlier assume a stationary free surface when computing the electromagnetic force. However, this force is often at leading order in the vicinity of the arc. In the same region, the metal drop transfer leads to a periodic deformation of the melt pool free surface. In the final part of the thesis, the model was extended to account for free surface deformation when computing the electromagnetic force. This extension was applied to experimental test cases, and a comparison was made with simulation results obtained using the stationary electromagnetic force model. Significant differences in the results were observed, particularly in predicting the experimentally observed fingertip-shaped fusion zone geometry. The proposed improvement in the electromagnetic force model provided better predictions in this regard.

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  • 235.
    Aryal, Pradip
    et al.
    University West, Department of Engineering Science, Division of Welding Technology.
    Choquet, Isabelle
    University West, Department of Engineering Science, Division of Welding Technology.
    Melt pool electromagnetic force model extended to account for free surface deformation: Application to gas metal arc2024In: International Journal of Heat and Mass Transfer, ISSN 0017-9310, E-ISSN 1879-2189, Vol. 221, p. 124987-124987, article id 124987Article in journal (Refereed)
    Abstract [en]

    Computational fluid dynamics models with free surface tracking intended to simulate the melt pool produced by an electric arc usually model the electromagnetic force ignoring the deformation of the free surface. However, with an arc heat source, the electromagnetic force is known to be among the leading-order forces, especially at high currents. In addition, the free surface can undergo significant deformations, especially in the presence of metal transfer. In the present study, a generalization of the electromagnetic force model that accounts for the deformation of the free surface is therefore proposed. Test cases with a pulsed gas-metal arc that transfers one metal drop per pulse were investigated experimentally at three different travel speeds to provide validation data. The cases were simulated with both the proposed and the earlier model to assess the influence of the new developments. The results showed that, in the regions where both models determine the force, the discrepancy between the models’ results can reach up to an order of magnitude. Especially, the earlier model overestimates the electromagnetic force deep into the melt pool. On the other hand, it neglects it in the liquid metal that is located at an elevation above the original upper surface of the workpiece, while the proposed model showed that in this area the intensity of the electromagnetic force is the largest. These significant discrepancies result in non-negligible differences in the predicted melt pool thermal flow and geometry. Especially, the propose dextended model provides an improved prediction of the fingertip-shaped fusion boundary.

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  • 236.
    Aryal, Pradip
    et al.
    University West, Department of Engineering Science, Division of Welding Technology.
    Hurtig, Kjell
    University West, Department of Engineering Science, Division of Welding Technology.
    Sikström, Fredrik
    University West, Department of Engineering Science, Division of Production Systems.
    Nilsson, Håkan
    Chalmers University of Technology Mechanics and Maritime Sciences, Fluid Dynamics, SE-412 96 Gothenburg, (SWE).
    Choquet, Isabelle
    University West, Department of Engineering Science, Division of Welding Technology.
    Effect of Substrate Orientation on Melt Pool during Multi-Layer Deposition in V-Groove with Gas Metal Arc2021In: Proceedings of the 7th World Congress on Mechanical, Chemical, and Material Engineering (MCM'21) / [ed] Huihe Qiu, 2021, article id HTFF 130Conference paper (Refereed)
    Abstract [en]

    Thermo-fluid dynamic and experimental approaches are used to investigate the influence of 20° uphill, downhill and sideway substrate orientation during metal deposition over a previously deposited bead in a V-groove. The computational fluid dynamic model with free surface deformation and metal transfer gives insight into the melt pool flow and causes of defect formation observed on the solidified beads. The experimental metallographs, high-speed images and computational results show good agreement. It is found that the deposition of a second layer on a smooth first layer cooled down to room temperature leads to large changes in melt pool flow patternat 20° substrate inclination compared to flat condition. It results in undercut and humps with the uphill orientation and undercut with the side inclination. Therefore, lower angle range is necessary for multilayer gas metal arc deposition for these two last configurations.

  • 237.
    Aryal, Pradip
    et al.
    University West, Department of Engineering Science, Division of Welding Technology.
    Sikström, Fredrik
    University West, Department of Engineering Science, Division of Production Systems.
    Nilsson, H.
    Department of Mechanics and Maritime Sciences, Chalmers University of Technology, Gothenburg.
    Choquet, Isabelle
    University West, Department of Engineering Science, Division of Welding Technology.
    Comparative study of the main electromagnetic models applied to melt pool prediction with gas metal arc: Effect on flow, ripples from drop impact, and geometry2022In: International Journal of Heat and Mass Transfer, ISSN 0017-9310, E-ISSN 1879-2189, Vol. 194, article id 123068Article in journal (Refereed)
    Abstract [en]

    The present work concerns the electromagnetic force models in computational fluid dynamics simulations of melt pools produced with electric arcs. These are commonly applied to gas metal arcs with metal transfer, in welding and additive manufacturing. Metal drop impact on the melt pool is thus included in this study. The electromagnetic force models applied in literature use either numerical solutions of Poisson equations or one of the two analytical models developed by Kou and Sun, or Tsao and Wu. These models rely on assumptions for which the effect on the melt pool predictions remains to be understood. The present work thoroughly investigates those assumptions and their effects. It has been supported by dedicated experimental tests that did provide estimates of unknown model parameters and validation data. The obtained results show that the assumptions that fundamentally distinguish these three models change the electromagnetic force, including the relation between its components. These changes, which can also be spatially non-uniform, are large. As a result, these models lead to significantly different recirculation flow pattern, thermal convection, melt pool morphology, bead dimensions, and free surface response to the metal transfer. We conclude by proposing conditions in which each of these models is suited or questionable.

  • 238.
    Asad, Ahmed
    et al.
    University West, Department of Engineering Science, Avdelningen för produktionssystem (PS).
    Sallander, Rikard
    University West, Department of Engineering Science, Avdelningen för produktionssystem (PS).
    Balansering och tidsoptimering av materialsatsning till F12-monteringen på Parker PMDE Trollhättan2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In industries, the management tools of Lean Production are used to develop and streamline operations in a way to reduce waste and lead times in all processes. Parker PMDE in Trollhättan manufactures hydraulic machines. Since the 90´s, Parker has pursued business development under the management principles of Lean Production. One of the next steps in Parkers continuous improvement was to explore opportunities to develop a kitting department so that a worker could provide the assembly with the material quickly without surplus resources. In the current situation, there is an imbalance from the kitting station towards the tact times in the assembly station because it takes longer at the kitting station to pick materials for four hydraulic machines, than it takes for the assembly station to consume these kits of materials.The aim of the thesis was to develop suggestions for improvement where a worker could perform the kitting process in less than 16 minutes. The interim objectives were to do a survey of the times and activities within the kitting process. The boundaries of the project was not to examine processes outside the kitting station. The project was designed according to DMAIC methodology, which is a project model for fact-based problem solving and clear structure. The methods used in the data collection were observation and analysis of video footage applying the software called AviX Method. Video recordings were categorized as different activities in the kitting process such as transport, picking, scanner time, pre-assembly and uncategorized time. Activities that were time consuming and did not add value to the process were identified. These data measures were the basis for the solution proposals.Based on these results and using brainstorming, solution proposals were generated together with the engineers and material handlers. The solution proposals that met the objective of the project of picking a 4-set of materials in 16 minutes were: Pick by voice, Pick-by-light, Ring Scanner and Relocation of one pre-assembly operation. Pick by voice is considered to be the most appropriate solution for the company since it reduces picking times, scanning times and is a flexible system. Two more proposed solutions were developed that did not meet the objective of the project, but are considered worth investigating further based on Lean Production and ergonomic reasons. These proposed solutions consisted of changing the picking route and the installation of a magnetic lift.

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  • 239.
    Asala, G.
    et al.
    University of Manitoba, Winnipeg, R3T 5V6, Canada .
    Andersson, Joel
    University West, Department of Engineering Science, Division of Mechanical Engineering.
    Ojo, Olanrewaj A.
    University of Manitoba, Winnipeg, R3T 5V6, Canada .
    Precipitation behavior of gamma′ precipitates in the fusion zone of TIG welded ATI 718Plus®2016In: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 87, no 9-12, p. 2721-2729Article in journal (Refereed)
    Abstract [en]

    The precipitation behavior of the main strengthening phase, γ′ precipitates, in ATI 718Plus® superalloy after Tungsten Inert Gas (TIG) welding and postweld heat treatments has been studied. In contrast to electron beam welding, where no γ′ precipitates are reported to form in the as-welded condition, analytical transmission electron microscopy study in this work revealed the formation of γ′ precipitates after the TIG welding, albeit in a non-uniform distribution manner. This is attributable to a more extensive elemental microsegregation that occurred into the interdendritic liquid and slower cooling rate during the TIG welding, which also induced the formation of interdendritic Nb-rich Laves phase particles and MC-type carbides. Theoretical calculations were performed to study the influence of Nb microsegregation, on both the kinetics and extent of γ′ precipitation, and the results agree with experimental observations. It is found that the precipitation kinetics, and not the extent of γ′ precipitate formation in the fusion zone, during postweld heat treatments is affected by the micro-segregation of Nb that produced Laves phase particles during the weld solidification.

  • 240.
    Asala, G.
    et al.
    University of Manitoba, Department of Mechanical Engineering, Winnipeg, Canada.
    Andersson, Joel
    University West, Department of Engineering Science, Division of Welding Technology.
    Ojo, Olanrewaju
    University of Manitoba, Department of Mechanical Engineering, Winnipeg, Canada.
    Microstructure Dependence of Dynamic Impact Behaviour of ATI 718plus® Superalloy2018In: Proceedings of the 9th International Symposium on Superalloy 718 & Derivatives: Energy, Aerospace, and Industrial Applications / [ed] Ott, E., Liu, X., Andersson, J., Bi, Z., Bockenstedt, K., Dempster, I., Groh, J., Heck, K., Jablonski, P., Kaplan, M., Nagahama, D. and Sudbrack, C., Springer, 2018, p. 369-378Conference paper (Refereed)
    Abstract [en]

    ATI 718Plus® is a γ′-strengthened nickel-based superalloy developed to substitute the widely used Alloy 718 in aero-engine applications. This newer superalloy is a candidate material for aero-engine turbine structures, with the requirement to withstand impact loading occurring at high strain rates during turbine blade out events. Furthermore, the understanding of the high strain rate response of ATI 718Plus® is important in optimising its machinability during cutting operations. To predict and model the behaviour of ATI 718Plus® during these events and in other dynamic impact applications, proper understanding of the high strain rate behaviour of the alloy is important, but not presently available. Therefore, in this work, the influence of microstructural condition and strain rates on dynamic impact behaviour of ATI 718Plus®, using a modified version of direct impact Hopkinson bar, is investigated. It is observed that the age-hardened alloy exhibits a significantly reduced strain hardening and strain rate hardening capabilities compared to the solution heat treated microstructure. Furthermore, microstructural examination of the deformed samples shows that the formation of adiabatic shear bands, which usually serve as damage nucleation site, is substantially suppressed in the solution heat treated microstructure, while the aged microstructure exhibits high propensity to form localised shear bands.

  • 241.
    Asala, G.
    et al.
    University of Manitoba, Department of Mechanical Engineering, Winnipeg, Canada.
    Khan, A. K.
    University of Manitoba, Department of Mechanical Engineering, Winnipeg, Canada.
    Andersson, Joel
    University West, Department of Engineering Science, Division of Mechanical Engineering. University West, Department of Engineering Science, Division of Welding Technology.
    Ojo, O. A.
    University of Manitoba, Department of Mechanical Engineering, Winnipeg, Canada.
    Microstructural Analyses of ATI 718Plus® Produced by Wire-ARC Additive Manufacturing Process2017In: Metallurgical and Materials Transactions. A, ISSN 1073-5623, E-ISSN 1543-1940, Vol. 48A, no 9, p. 4211-4228Article in journal (Refereed)
    Abstract [en]

    A detailed microstructural study of ATI 718Plus superalloy produced by the wire-arc additive manufacturing (WAAM) process was performed through the use of scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron probe micro-analysis (EPMA), and electron backscatter diffraction (EBSD). Extensive formation of eutectic solidification microconstituents including Laves and MC-type carbide phases, induced by micro-segregation, are observed in the build of the alloy in the as-deposited condition. Notwithstanding the significant segregation of niobium (Nb), which has been reported to promote the formation of the delta-phase in ATI 718Plus, only eta-phase particles are observed in the deposit. Excessive precipitation of eta-phase particles is found to be linked to Laves phase particles that are partially dissolved in the deposit after post-deposition heat treatment (PDHT). The EBSD analysis shows a high textured build in the aOE (c) 100 > directions with only a few misoriented grains at the substrate-deposit boundary and the top of the deposit. Investigation on the hardness of the build of the alloy, in the as-deposited condition, showed a softened zone about 2 mm wide at the deposited metal heat affected zone (DMHAZ), which has not been previously reported and potentially damaging to the mechanical properties. An extensive analysis with the use of both microstructural characterization tools and theoretical calculations shows that the DMHAZ has the lowest volume fraction of strengthening precipitates (gamma’ and gamma aEuro(3)) in terms of their number density, which therefore induces the observed softness. Delayed re-precipitation kinetics and the extent of the precipitation of gamma’ and gamma aEuro(3) in the DMHAZ which is related to the diffusion of segregated solute elements from the interdendritic regions are attributed to this phenomenon. The microstructural analyses discussed in this work are vital to adequate understanding of properties of ATI 718Plus produced by the additive manufacturing process technique.

  • 242.
    Asala, Gbenga
    et al.
    University of Manitoba, Department of Mechanical Engineering, Winnipeg, R3T 5V6, Canada.
    Andersson, Joel
    University West, Department of Engineering Science, Division of Welding Technology.
    Ojo, Olanrewaj A.
    University of Manitoba, Department of Mechanical Engineering, Winnipeg, R3T 5V6, Canada.
    Analysis and constitutive modelling of high strain rate deformation behaviour of wire-arc additive-manufactured ATI 718Plus superalloy2019In: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 103, no 1-4, p. 1419-1431Article in journal (Refereed)
    Abstract [en]

    A fundamental prerequisite for obtaining realistic finite element simulation of machining processes, which has become a key machinability assessment for metals and alloys, is the establishment of a reliable material model. To obtain the constitutive model for wire-arc additive-manufactured ATI 718Plus, Hopkinson pressure bar is used to characterise the flow stress of the alloy over a wide range of temperatures and strain rates. Experiment results show that the deformation behaviours of as-deposited ATI 718Plus superalloy are influenced by the applied strain rate, test temperature and strain. Post-deformation microstructures show localised deformation within the deposit, which is attributable to the heterogeneous distribution of the strengthening precipitates in as-deposited ATI 718Plus. Furthermore, cracks are observed to be preferentially initiated at the brittle eutectic solidification constituents within the localised band. Constitutive models, based on the strain-compensated Arrhenius-type model and the modified Johnson-Cook model, are developed for the deposit based on experimental data. Standard statistical parameters, correlation coefficient (R), root-mean-square error (RMSE) and average absolute relative error (AARE) are used to assess the reliability of the models. The results show that the modified Johnson-Cook model has better reliability in predicting the dynamic flow stress of wire-arc-deposited ATI 718Plus superalloy. © 2019, Springer-Verlag London Ltd., part of Springer Nature.

  • 243.
    Asala, Gbenga
    et al.
    University of Manitoba, Department of Mechanical Engineering, Winnipeg, Canada.
    Andersson, Joel
    University West, Department of Engineering Science, Division of Welding Technology.
    Ojo, Olanrewaj A.
    University of Manitoba, Department of Mechanical Engineering, Winnipeg, Canada.
    Hot corrosion behaviour of wire-arc additive manufactured Ni-based superalloy ATI 718Plus®2019In: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 158, article id 108086Article in journal (Refereed)
    Abstract [en]

    The hot corrosion behaviour of wire-arc additive manufactured and wrought ATI 718Plus® are studied. ATI 718Plus® produced by the additive manufacturing process, in the as-processed condition, exhibits a significantly lower hot corrosion resistance in comparison to the wrought alloy. Analytical electron microscopy and spectroscopy techniques, with corroboration by thermodynamic calculations, are used to identify the underlying cause of the poor hot corrosion resistance. Based on the understanding accrued from the analyses, post-processing heat treatments are used to improve the hot corrosion resistance, which is valuably pertinent to the application of ATI 718Plus® produced by additive manufacturing in hot corrosive environments. © 2019 Elsevier Ltd

  • 244.
    Asala, Gbenga
    et al.
    University of Manitoba, Department of Mechanical Engineering, Winnipeg, R3T 5V6, Canada.
    Andersson, Joel
    University West, Department of Engineering Science, Division of Welding Technology.
    Ojo, Olanrewaj A.
    University of Manitoba, Department of Mechanical Engineering, Winnipeg, R3T 5V6, Canada.
    Improved dynamic impact behaviour of wire-arc additive manufactured ATI 718Plus®2018In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 738, p. 111-124Article in journal (Refereed)
    Abstract [en]

    The dynamic response and impact resistance of wire-arc additive manufactured (AMed) and wrought ATI 718Plus in different heat treatment conditions are characterised by using a direct impact Hopkinson pressure bar system. In addition, microstructural analyses of the alloys, before and after impact, are characterised by using advanced microscopy techniques, including scanning electron and transmission electron microscopies. The experimental results show that the impact resistance of the AMed alloy in the as-processed condition is inferior to that of the wrought alloy. The lower impact resistance is attributed to the presence of eutectic solidification constituents in the interdendritic regions and to the inhomogeneous distribution of the strengthening precipitates in the deposit. After the application of the recommended heat treatment for ATI 718Plus, excessive formation of η-phase particles are observed in the microstructure in addition to Laves phase particles. Since the recommended heat treatment for ATI 718Plus is not sufficient to eliminate the deleterious phases and optimise the properties of the alloy, a novel heat treatment procedure is proposed. Dynamic impact study of the AMed alloy after the application of the proposed approach shows that the alloy exhibits a dynamic response and impact resistance comparable to those of the wrought alloy. Furthermore, under high impact momentum, both the wrought and the AMed alloys fail due to the adiabatic shear band. A transmission electron microscopy analysis of the deformed alloys suggests the dissolution of the γ’ precipitates in the shear band as well as in the adjacent regions to the shear band. Increase in the rate of dissolution of the precipitates due to strain-assisted diffusion coupled with an increase in the adiabatic temperature during deformation, are likely causes of the dissolution of the precipitates in the shear band regions. © 2018 Elsevier B.V.

  • 245.
    Asala, Gbenga
    et al.
    University of Manitoba, Department of Mechanical Engineering, Winnipeg, Canada (CAN).
    Andersson, Joel
    University West, Department of Engineering Science, Division of Welding Technology.
    Ojo, Olanrewaju A.
    University of Manitoba, Department of Mechanical Engineering, Winnipeg, Canada (CAN).
    A study of the dynamic impact behaviour of IN 718 and ATI 718Plus® superalloys2019In: Philosophical Magazine, ISSN 1478-6435, E-ISSN 1478-6443, Vol. 99, no 4, p. 419-437Article in journal (Refereed)
    Abstract [en]

    The dynamic impact response of IN 718 and ATI 718Plus®, in both the solution heat treated and age-hardened conditions, were investigated at different deformation temperatures and strain rates using a direct impact Hopkinson pressure bar. Analyses of the results provide a vital but previously not reported information that the ATI 718Plus® offers a higher resistance to damage during high strain rate ballistic impact deformation compared to the most widely used Iron-nickel based superalloy, Inconel 718. ATI 718Plus® showed higher strain hardening and strain rate sensitivity, in both heat treatment conditions, than IN 718. The difference in the deformation behaviour of both alloys, in the annealed condition, is attributable to the compositional modification in ATI 718Plus® which has been reported to lower its stacking fault energy and increases the tendency for deformation twinning. However, in the age-hardened condition, the difference is believed to be related to the disparity in the operative strengthening mechanism, of the precipitates present in both alloys. Furthermore, a higher susceptibility to strain location and the formation of adiabatic shear band, in aged IN 718, is attributable to the stronger temperature-softening characteristics observed in the alloy and to the limited strain hardening tendency under dynamic impact loading. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.

  • 246.
    Ashok Kumar Prasanna Kumari, Athira
    University West, Department of Engineering Science.
    Discrete Event Simulation of the Paint shop at VBG Truck Equipment: A method for Work shift Optimization and Balanced Production flow2022Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The background for this thesis work emanates from a desire to drive the production of the VBG Truck Equipment factory in Vänersborg a step further to catch up with the Industry 4.0 standards. Discrete Event Simulation (DES) is a widely adopted tool within industries to model real-world systems to improve their processes. The concern of bottlenecks is a vital problem in optimizing and improving the efficiency of production processes. Finding and investigating bottlenecks is one of the primary considerations of all manufacturing industries.The company aims to enhance its logistics by using automation in its processes. This work focusses on the Paint shop part of the VBG factory. Thus, the VBG would like to analyse the methods to reduce the bottlenecks and the waiting time in the Paint shop production process. There were no simulation models available to analyse the existing paint shop pro duction flow; therefore, a Discrete Event Simulation (DES) model of the VBG Paint shop was built to investigate the bottlenecks and improvement methods.

    In this thesis work, the DES model of the existing Paint shop that uses the Last in First Out (LIFO) method was investigated to find the throughput and lead time for the products. In comparison, a First in First Out (FIFO) method was used to get a balanced production flow, and its effects were studied. The company currently uses two shifts in their Paint shop, so the alternate arrangement of shifts using the same number of operators was analysed. The analysis of three shifts with the same number of operators gave more efficiency than the existing one, and three shifts with an increasing number of operators were also compared. The shift arrangements were compared with both the LIFO and FIFO methods, and FIFO provided more throughput and balanced production flow.

    The main bottleneck was identified in the forklift transport waiting time, so an alternate layout using a power and free conveyor system was developed. This alternate arrangement reduced the bottlenecks and produced an increased output. The alternate layout was also compared with LIFO and FIFO methods; FIFO was the most efficient one. The shift patterns were also analysed, and the three shifts with a 50 percent increase in staff can reduce the stock build-up during the start of the first shift. As of this study, it was identified that the alternate model with FIFO is the most suitable solution for the company, and in the coming years, they intend to implement that. From the experimental results obtained, DES can be chosen as a method to analyse the problems associated with limiting the capacity of production. The DES modelling can be extended to the other processes in the factory and can be used for improving logistics and inventory management. The company production flow can be further advanced by evaluating the changes that can be implemented in the factory with real-time data.

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  • 247.
    Asp, Patrik
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Säkerhetsanalys av trådlöst nätverk2015Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    The purpose of the study is to observe a corporate wireless network to find potential security holes. The goal of this is to make the network more secure and able to withstand attacks. The method is to interview the IT manager at the company to get a good overview of how their wireless network looks like. It's also applied a risk analysis to eventually use acombination of a risk analysis and interview to get results. The results show that the company has several security holes in their wireless network. Safety flaws that the company has is based on that a hacker must be on the inside of the network to take advantage of these security holes. Measures have been given to the company so that they can fix the security holes that have been found. But the company is keeping high standards overall.

  • 248.
    Atar, Mohammad
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Förstudie till fältbusslaboration för elkraftstillämpningar2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis describes how to develop a fieldbus lab. The lab will be part of the course Data communications with electric power applications (course code DML200) at University West. The goal and purpose of this lab will be to allow students learn how to set up, commission and troubleshoot equipment. In this context, the course also directed towards electric power technology and it is important for the Bachelor programme in electrical engineering with specialization in power electric because the course is included in the program.

    The work was aimed at developing suitable equipment which must include the appropriate number of protection relays and the necessary components for communication via ProfiBus such as PLC controllers, I/O-module, the Operation Panel. Different companies where asked about the prices of the components and a collection of quotations was made.

    The response from three out of five different companies indicated that ProfiBus is an old system. Everyone wondered why ProfiBus was chosen as a communications system over other system such as Ethernet with ModBus. According to these companies ProfiBus is an old communication system and it is expensive. It could save some money if the problem was solved with ethernet with ModBus because of the availability of the manufacturers. Finally the lab idea was illustrated with a wiring diagram.

  • 249.
    Augustsson, Angelica
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Albertsson, Cecilia
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Lantmäterier i Norden: Dess centralorganisationer och det nordiska samarbetet2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of the study is to highlight similarities and differences between the different central organizations for surveying in the Nordic counties. The Nordic cooperation’s will be examined to gain a deeper understanding for the cooperation between the countries.

    Denmark’s organization is consisted by several boards. Those who perform cadastral proce-dure are private operators who report changes in property to the boards for registration. The organization is complex and difficult to get an overview of. The central organization of Finland is large and extensive, with multiple devices, areas and departments controlled by directors. The organization is owned by the state where both cadastral procedure and cadastre is within the central organizations responsibility. The central organization of Norway is owned by the state, with few work areas and specializations. They handle maps, cadastre and registration. It is Jordsifteretten who perform major ordinances and municipalities perform the minor. They are investigation whether the cadastral procedure should be private in order to develop and improve the surveying process in the country. Sweden like Finland has a central organization owned by the state who is handling cadastral procedure and cadastre. The organization is built in a number of different divisions that manage registration of property, cadastre and geodesy. In addition to the government offices are also municipal offices. In both the central organizations and in the countries different surveying associations are Nordic cooperation’s. Both seek to strengthen communion and enable exchange of expertise between the counties.

    The central organizations of Denmark, Finland, Norway and Sweden are different from each other, but there are still some similarities. The possibility to create an organization that works across the countries in common, is limited by national legislation. A unified central organization will therefore not be formed, nor is it the purpose of the Nordic cooperation’s. By mapping the central organizations an overview is created of the variations between the countries. But despite these differences succeed to get similar results in terms of surveying operations in the Nordic countries.

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  • 250.
    Augustsson,, Jimmy
    et al.
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Printz, Kristoffer
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Svensson, Erik
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Larmanalys för Vattenfall Vattenkrafts produktionsanläggningar längs Göta Älv2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Vattenfall Vattenkraft AB owns 57 large scale hydro power plants in Sweden with installed power exceeding 10 MW. The study relates to four of the plants located along Göta river. This report analyzes incidents and the related remedial actions that have occurred during the period 2014 – 2017 as well as the alarm and control systems with the aim to identify potential improvements. The incidents are categorized by error, what actions have been undertaken to correct the issue, plant and season. The incidents have predominately originated in the turbine and generator facilities and have been caused by abnormal levels or temperatures. During summer and winter time, this is mainly due to variation in temperature and flow in the river. The four plants have caused a similar amount of alarms, which is interesting as there is a large variation in age. The analysis does not identify any reoccurring issues which were previously unknown to the company, but the authors recommends that an investigation is conducted to assess if eel screens should be installed for the cooling pumps of Lilla Edet. The alarms are generated in the plants and are sent to the control facility in Bispgården near Sundsvall, where the operator calls the local engineer on duty in Trollhättan. The engineer subsequently goes to the plant to access detailed information on the incidents from the local computers. This report examines the possibility to provide the engineer on duty with detailed information from the plant computer via VPN. This would be possible to implement but would require a detailed assessment of the security implications. The status of the alarm system have also been assessed as it have been modified and extended retroactively, and there is currently no comprehensive overview. The conclusion is that a review of the list of incident codes and their priority is recommended.

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