Change search
Refine search result
210211212213214215216 10601 - 10650 of 11191
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 10601.
    Uczak de Goes, Wellington
    et al.
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Somhorst, Joop
    Volvo Car Corporation, Göteborg, Sweden.
    Markocsan, Nicolaie
    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.
    Illkova, Kseniya
    Institute of Plasma Physics, Prague, Czech Republic.
    Suspension Plasma-Sprayed Thermal Barrier Coatings for Light-Duty Diesel Engines2019In: Journal of thermal spray technology (Print), ISSN 1059-9630, E-ISSN 1544-1016, Vol. 28, no 7, p. 1674-1687Article in journal (Refereed)
    Abstract [en]

    Demands for improved fuel efficiency and reduced CO2 emissions of diesel engines have been the driving force for car industry in the past decades. One way to achieve this would be by using thermal spraying to apply a thermal insulation layer on parts of the engine’s combustion chamber. A candidate thermal spray process to give coatings with appropriate properties is suspension plasma spray (SPS). SPS, which uses a liquid feedstock for the deposition of finely structured columnar ceramic coatings, was investigated in this work for application in light-duty diesel engines. In this work, different spray processes and materials were explored to achieve coatings with optimized microstructure on the head of aluminum pistons used in diesel engine cars. The functional properties of the coatings were evaluated in single-cylinder engine experiments. The influence of thermo-physical properties of the coatings on their functional properties has been discussed. The influence of different spray processes on coating formation on the complex piston head profiles has been also discussed. The results show that SPS can be a promising technique for producing coatings on parts of the combustion chamber, which can possibly lead to higher engine efficiency in light-duty diesel engines.

  • 10602.
    Uddh, John-Eric
    et al.
    University West, School of Business, Economics and IT, Divison of Informatics.
    Van Herck, Arnaud
    University West, School of Business, Economics and IT, Divison of Informatics.
    Augmented reality inom tillverkningsindustrin2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    GKN Aerospace is today one of the world's leading suppliers of aerospace technology and components. They deliver to both small and large aircrafts and operate in 14 different countries. Continuous high demands on quality and the effort to always improve, have made it possible for the company to explore new opportunities to facilitate and shorten the lead times of components in production. One way of achieving this can be by including augmented reality (AR) technology in their workflow. This technology is about combining a virtual layer on top of your reality.

    The purpose of the study was to investigate how other operators in the industry are using AR technology, which design principles exist and then create a prototype in the form of a proof of concept to demonstrate how AR can facilitate the maintenance work of operators at GKN Aerospace. The study used a qualitative research approach to gain knowledge about how an AR application can facilitate maintenance work for operators at GKN Aerospace.

    The method began with an exploratory literature study followed by a semi-structured interview used for mapping the workflow. Consequently, a prototype was created which was then tested by a total of 6 employees, whereupon follow-up interviews were carried out to get more knowledge about each test user's perception. The selection was based on a convenience choice with the minimum requirement that the tester was an employee at GKN working on the manufacturing stage at their plant in Trollhättan, Sweden.

    The outcome of the initial interviews and e-mail communication with GKN resulted in the finding that the greatest potential for efficiency improvements by the prototype was in the troubleshooting process, by allowing an operator to identify defects using Microsoft HoloLens. The result of the user tests showed a positive attitude to future implementations of AR technology at GKN.

    The findings of the study show that AR technology has a potential role to play in the future when it comes to maintenance and troubleshooting. The study also shows that general design principles are well suited for AR applications as well. All participants in the study perceived the prototype as easy to understand and very intuitive. It also appeared that, even though the participants in the study posed positively to the AR-technology, they didn't think it could be implemented in the near future.

  • 10603.
    Uddén, Angelica
    et al.
    University West, Department of Health Sciences, Nursing Programme.
    Andersson, Johan
    University West, Department of Health Sciences, Nursing Programme.
    Sjuksköterskans upplevelser av att vårda patienter i livets slutskede: En litteraturbaserad studie2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Background: The aim of this study was to observe nurses' experiences of palliative care. The method used was a literary survey based on 10 qualitative studies. The studies were published in scientific journals.

    Result: Two themes and four categories were found. The themes were: "The nurse as coordinator" and "The nurse's experienced needs for improvement". The categories were "Communication", "Relation/commitment", Work routines" and "Education/Further education". Our study indicates that the experiences concerning palliative care among nurses are similar. The nurses experienced that they had a coordinating role in the palliative nursing situation. They also expressed the need for developed work routines together with additional education and training in the field of palliative care.

    Conclusion: a majority of the examined studies stress the fact that nurses were responsible for the overall planning of the palliative care. This general overview of the entire work field provides nurses with necessary tools to define any needs for improvement that might occur in the daily care. The professional attitudes among nurses in palliative care contributed to the request of need of support and continuous education in order to be able to provide good quality care. If the health care quality measurements were not reached the nurses would feel inadequate in their role as coordinating nurses. Nurses argue that they are in need of continuous knowledge development in order to achieve greater comfort in their professional situation.

  • 10604.
    Uggla, Fred
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Wong, Teddy
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Virtualisering med SmartOS: en utvärdering av inkluderad mjukvara och verktyg2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    SmartOS is a Unix-like operating system which includes Zones, KVM, ZFS, DTrace and Crossbow. The purpose of this package of software is to supply a hypervisor capable of running virtual machines on operating system-level and hardware-level. This thesis evaluates SmartOS and the possibilities of the software combination. The intention is to determine if SmartOS is ready for a production environment by performing six scenarios with specific requirements. A survey regarding the result, aimed at system administrators, indicates that SmartOS does not meet the requirements. The survey also shows that the respondees are satisfied with their existing virtualization solutions.

  • 10605.
    Uhlman, Christina
    et al.
    University West, Department of Health Sciences, Section for nursing - undergraduate level.
    Robertsson, Ellinor
    University West, Department of Health Sciences, Section for nursing - undergraduate level.
    En stympad kropp: Kvinnors upplevelser av att ha genomgått en mastektomi till följd av bröstcancer2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Background: Breast cancer is the most common cancer form among women. In Sweden, approximately twenty women receive a breast cancer diagnosis every day. Most of the women who get affected with breast cancer get surgical treatment. Mastectomy is a surgical method of treatment involving the removal of one or both breasts. This may lead to several emotions regarding body image, sexuality and their womanliness. Aim: The aim of this study is to describe women's experiences of having undergone a mastectomy as a result of breast cancer. Method: A literature-based method were used to obtain woman´s experiences of having undergone a mastectomy. The results of the studies were analyzed using a five- step model. The analysis resulted in three themes and eight subthemes. Results: The results had three themes and eight subthemes. The theme To lose a part of their identity as a woman with the subthemes To lose a breast and Not to live up to the women's ideals. The theme To feel insufficient with the subthemes A changing relationship and A sense of shame. The theme To be reconciled with having undergone a mastectomy with the subthemes Alone is not strong, A sense of gratitude, Not a big deal and The influence of time on the experience after a mastectomy. Conclusion: A mastectomy can give women experiences that may seem difficult to handle and that adversely affect their lives. Yet women can still achieve health because the negative experiences can be alleviated. Nurses can be an important function for supporting women to health

  • 10606.
    Ulasi, Micheal
    University West, Department of Economics and IT, Division of Computer Engineering.
    IP surveillance comparison between a Banana Pi camera system and a Raspberry Pi B+ camera system2015Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    This report discusses the implementation of IP surveillance technology using a decentralized architecture. The research focuses on the comparison between a Banana Pi camera system and a Raspberry Pi B+ camera system. This implies testing both systems as decentralized camera system. Both Pi camera systems, are running Raspbian OS and on them a CSI camera module is attached, and use their VLC media player application that is configured with HTTP/RTSP protocol to send video streams to clients on the LAN. The configuration uses either CIF and 1080P video resolution with motion and without motion respectively, at different intervals in the experiment.

    Information obtained from the research analyzes, revealed that the Raspberry Pi B+ is most suitable as a decentralized camera system than the Banana Pi is. It was possible for the Banana Pi to stream video using HTTP protocol and 1080P resolution with motion and without motion, but it could not use RSTP protocol and CIF resolution. Furthermore, the system crashed whenever the number of remote video streams on the Banana Pi were above than one connection. Although, during this one connection, the CPU usage was 100% and the memory usage was above 200MB. The bandwidth consumption was low, and the video quality was acceptable.The Raspberry Pie B+, processed most remote video streams and had most acceptable video qualities during the use of CIF resolution with motion and without motion, in contrast with use of 1080P with motion and without motion.

    Results also indicated that the Raspberry Pi B+ performed best with the use of CIF without motion, because it served all 50 remote video streams with 33.5% CPU usage. The Raspberry Pi B+, demonstrated poor performance during the 1080P with motion because it served just five remote video streams with 28.8% CPU usage. In overall, the bandwidth and memory usage increased simultaneously on the Raspberry Pi B+ as the number of remote video streams it served increased.

  • 10607.
    Ulfsdotter, Cornelia
    et al.
    University West, Department of Economics and IT, Division of Business Administration.
    Axelsson, Gustav
    University West, Department of Economics and IT, Division of Business Administration.
    Implementering av sociala medier som marknadsföringsverktyg: an studie om marknadsavdelningar på den svenska modemarknaden2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Research question: How is an implementation of social media as a marketing tool performed? What effects has an implementation of social media marketing on the marketing departments operations and structure?

    Purpose: The purpose with this study is to provide knowledge on how an implementation of social media marketing is carried out by companies in the distributor part of the Swedish fashion markets supply chain. This study will also contribute to understanding what effects an implementation of social media marketing has on the company's marketing departments in the case of operations and structure.

    Method: This study was conducted with a qualitative approach with semi structured interviews with four selected respondents working in marketing departments. In the analysis, we have assumed the analysis model and made a thematic breakdown.

    Conclusion: We have developed a series of questions that companies need to ask themselves during stages of the implementation that we regard as crucial. These questions are designed to ensure that the implementation follows the original plan, that the process is adapted after the company's resource-capabilities and utilizes the available resources in the most efficient way.

    We also see a difference when it comes to start-ups and older more established companies when researching how structure and operations are adapted to cope with new technologies like social media. While the start-ups integrate the use of social media marketing right from the start-up and thus have a functional structure and strategy from day one, the older more established companies have to integrate social media marketing into a structure and every day operations traditionally not are designed to handle a marketing tool like social media.

  • 10608.
    Ulucan Dayan, Civan
    University West, Department of Engineering Science, Division of Production System.
    Evaluation of an External Axis for Tool Manipulation in Robotized Laser Beam Welding2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Laser beam welding applications are widely used in the industry. However, laser beam welding applications have a very small position tolerance to an offset. In this project, the offset is defined as the distance between the point, which the laser tool welds, and the point which laser tool should weld the weld joint. In other words, the offset is the position error in a welding application. To perform successful welding, the laser beam must hit the exact coordinate of the weld joints to weld the parts together. For dealing with these inaccuracy issues, tool manipulation systems can be used. In this project, an external axis is used for the precise manipulation of the laser beam welding tool as a complement to robotic nominal movement. Input data to the external axis system is obtained from an image from a vision system of the work pieces which need to be welded.

    Tool manipulation systems are used to manipulate tools to ensure certain position accuracy during any application. The tool manipulation system in this project has two main parts; a seam tracking system (outside this project) and an external axis system. The seam tracking system gives an on-line measurement of the offset, and that there is a feedback loop with a controller, which gives the system information about how much to manipulate the external axis module to the external axis system. The seam tracking system consists of two main parts; a camera and the seam tracking image processing program. In the seam tracking system, a camera takes images of the work pieces which shall be welded. Then the seam tracking program calculates the offset by image processing. This estimated offset is the input for the external axis system. The external axis system has three main parts; the external axis program, input-output module and the external axis module. The external axis program is the system which controls the input-output module for manipulating the external axis module in this project. The external axis module manipulates the laser beam welding tool by changing the orientation of the tool in order to reduce the offset. This project is about the external axis system.

    There is a relationship between the offset input and the required manipulation angle of the external axis. In this project, the required manipulation angle is the external axis angle. By using this relationship, the laser beam welding tool can be manipulated to weld in the desired position. The same system can be used in applications which require high position accuracy.

    The evaluation of the external axis system emphasizes that the accuracy demand of the laser beam welding applications can be satisfied by an external axis system. However, the investigated external axis system behaves in a way that when the offset is larger than it supposed to be, the speed of the TCP movement slows down.

  • 10609.
    Ulvås, Erik
    University West, School of Business, Economics and IT, Division of Business Administration.
    Intern kommunikation inom bygg- och anläggning: En fallstudie av hur lean kommunikation kan användas för att förbättra den interna kommunikationen2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    There is currently a major generation shift in the construction industry. In addition, the need for personnel in construction is extremely high in western Sweden at the moment. This leads to the fact that many younger employees get a great leadership responsibility early in their career. Organizations in the construction industry are generally decentralized as many decisions are taken in the separate projects. In order to achieve effective transfer of experience between site managers as well as effective communication between the separate projects and the local management team, a well-suited communication model that promotes internal communication is required.

    The purpose of this study was to develop, adapt and implement a communication model within a production group at a construction company. This communication model is inspired by the Lean Visual Planning tool, which is a tool to visualize any problems in production. To achieve the purpose of the study, mixed methods were used, which was performed with a quantitative survey to make a zero-position analysis, and then the communication model was developed at a workshop with all respondents in the survey and then evaluated via an interview study.

    The theoretical frame of reference is based on scientific articles and previously developed theories of internal communication, effects on implementation of lean, lean in construction, Visual planning and theories about introducing new ways of working. Introducing new ways of working is presented in its four phases; the initiation phase, the anchoring phase, the implementation phase and the follow-up phase.

    The result of the study was a communication model inspired by Visual planning, where a 45-minute online meeting is conducted every two weeks. All projects must indicate a status (green, yellow or red) for the following categories; Work Environment, Crew planning and Production. In addition, the opportunity was given to the projects to address open questions to obtain a good experience feedback. The study's conclusion shows that employees need to be involved early in the design of a new way of working. However, it is too early to read the long-term effects of the implementation of the new communication model, but the response from the site managers was predominantly positive.

  • 10610.
    Ungethum, Eugen
    Strömstad Akademi.
    En reflektion över atmosfärens betydelse för vår livsmiljö2011In: Inre och yttre verklighet / [ed] Aadu Ott, Anders Steene och Gunnar Windahl, Strömstad: Strömstad Akademi , 2011, p. 71-75Chapter in book (Other academic)
  • 10611.
    Ungethüm, Eugen
    Strömstad Akademi.
    Atmosfärelektricitet och Elektroklimatologi: Betydelsen av luftelektriskafaktorer och strålning i yrkes- och arbetsmiljön2010In: Strömstad akademi: Vision och verklighet : Antologi 2010 / [ed] Aadu Ott & Carl E. Olivestam, Strömstad: Strömstad Akademi , 2010, p. 82-87Chapter in book (Other academic)
  • 10612.
    Ungethüm, Eugen
    Strömstad Akademi.
    Den blå planetens atmosfärelektriska system2013Report (Other academic)
    Abstract [en]

    Water and vapor (atmos) characterize the atmosphere and the permanently ongoing electrical processes – in time and space and scales reaching from atomic to global ones. Possibly electrical thunderstorm discharges have been a contributory source for the genesis of life by the conversion of inorganic material into organic molecules –a famous experiment let us assume that.Atmospheric electricity is the part of electro physics that treats the electrical processes in our atmosphere. Thefamous investigations by B. Franklin which shows that the lightning in thunderstorms is connected with electricaldischarges started the science in this geophysical area. Nearly all famous scientists in the electrical area (at thattime) have done contributions. It would overrun the frame of this abstract to mention them all – see instead theSwedish version.Atmospheric electricity research and development in Sweden has been carried out at Uppsala University,Meteorological Institute, Märsta Observatory. Prof. G.H. Liljequist established the base and instrumentation for advanced measurements in this field in the sixties. A modern electronic system for continuous measurements ofthe fundamental parameters: electrical field, positive and negative conductivity and vertical current density wasinstalled at Märsta Observatory – unique in Scandinavia. I got the mandate to carry out the research at the Observatory during 1964/65 (International Quiet Sun Year). Daily and annual variations of the ionosphericpotential have been determined by soundings of the electrical field up to 20 km height as a completion to the ground level measurements of the parameters field, current-density, positive and negative conductivity.Meteorological observations included temperature at several heights, humidity, pressure and cloudiness. The accomplishment of the measurements in the free atmosphere is described in more detail in the Swedish version and my thesis. It must be emphasized: It was an intricate work to start the balloons with the instrumental payloadsimultaneously with all the other stations on the globe which where involved in this international scientific program. Uppsala University was the only Scandinavian station involved. A milestone in atmospheric research in Sweden.Micro physically seen the air we breathe is ionized by natural sources (radioactivity and cosmic radiation) and anthropogenic ones. This has a lot of implications for our life and outdoor and indoor activities. Positive andnegative charges in a spectral mobility distribution are present as a function of the chemical composition of theair. Air pollution in form of gases and particles have a significant influence on air quality and can therefore be used as an air-quality-indicator in environmental investigations. This is especially important in indoor-areas and workplaces as a consequence of the use of modern building and furniture materials and floor cover. Asophisticated experimental research program has been carried out in the Office building (VBB ) in central Gothenburg (1985). The measurements included meteorological parameters outside the office building and theirinfluence on indoor air climate especially in inversion situations. We found that particle transport is primarily governed by the electric climate in indoor areas. This finding is of great importance for applications inoccupational hygiene and medicine. Summarized it can be stated that basic research has resulted in an outcome in a quite different area – a lot of years later.

  • 10613.
    Ungethüm, Eugen
    Strömstad Akademi.
    Från reaktorfysik till den övre atmosfärens fysik och sedan till sjukhusfysik: en spännande resa som forskare, lärare och ingenjör med mät- och medicinteknik som verktyg2012In: Bredd och djup: Strömstad akademi presenterar sig / [ed] Gunnar Windahl, Strömstad: Strömstad Akademi , 2012, p. 7-9Chapter in book (Other academic)
  • 10614.
    Upper, Martin
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Wilson, Johan
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Beredningsarbete av landsbygdsnät för områdena Fän, Suttene och Hermanseröd2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis is about the approach how the preparation work is done at TROLK El & Tele AB. The preparation work includes three areas, Hermanseröd, Fän and Suttene in Munkedal municipality. This preparation is the basis for the implementation of the project from Fortum Distribution AB. The project has come when Fortum decided to invest to ensure power quality and weather secure the network in the areas that was earlier mentioned. The preparation includes landowner contact, field work, permits and contract applications. Laying of cables and placement of the substations will also be established for the network owner. The voltage level of the network that is affected is up to 12kV to be transformed down to 0.4kV for subscribers. The project includes three substations, about 2.7 kilometers medium voltage cable, approximately 0.5 kilometers low voltage cable, 1 pc, cable box and about 1.7 kilometers demolition of the overhead line.

    The summary of the field work carried out is that the planner proposals of cable will be pursued for the most part, except for certain problematic locations where the cable placement will be changed.

  • 10615.
    Uppman, Angelica
    et al.
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Johansson, Linnea
    University West, Department of Engineering Science, Division of Computer, Electrical and Surveying Engineering.
    Storkvarter: En jämförande studie, från planering till genomförande2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this thesis is to review how public areas and facilities with private responsibility are implemented compared to the intentions described in zoning schemes made by municipalities in Västra Götaland. In this thesis ten local plans in six different municipalities has been reviewed.

    Zoning schemes with regulations, planning- and implementation descriptions, decisions about jointly-owned facilities, binding agreements between municipalities and developers has been studied to understand the intentions for the public areas and facilities. The result of the review was compared to reality by a survey made in each of the ten areas to see differences and similarities. A questionnaire was sent to all 49 municipalities in Västra Götaland to find out how often public areas and facilities are planned with private responsibility, how the developers' obligations are regulated in binding agreements and how the municipalities estimate how well their intentions are implemented.

    The result of the thesis shows that there are lack of knowledge among the civil servants about private responsibility for public areas and equipment and how to use it while zoning. Therefore, this method is rarely used in Västra Götaland. The intentions described by the municipalities were well implemented in reality in all reviewed areas. There were some deviations according to public facilities as parking spaces and playgrounds. In some areas the playgrounds hadn't been implanted at all despite zoningschemes and binding agreements.The conclusions from this thesis describes that the knowledge among employees needs tobe improved about which documents has legal basis and those documents which hasn't, to make sure that the municipalities' intentions are implemented. If the public areas and facilities are not regulated in a jointly-owned facility there could be discussions about responsibilities. Therefore, more knowledge is required among the municipalities in Västra Götaland.

  • 10616.
    Uppström, Mona
    University West, Department of Social and Behavioural Studies.
    Barns upplevelse av matematik i årskurs ett2006Independent thesis Advanced level (professional degree)Student thesis
  • 10617.
    Urban, Gråsjö
    et al.
    University West, Department of Economics and IT, Division of Law, Politics and Economics.
    Flood, Lennart
    Göteborgs Universitet.
    Regression Analysis and Time Use Data: A Comparison of Microeconometric Approaches with Data from the Swedish Time Use Survey1999In: Time Use: Research, Data and Policy / [ed] Merz, Joachim & Ehling, Manfred, Nomos Verlagsgesellschaft, 1999, p. 457-472Chapter in book (Refereed)
  • 10618.
    Urbath, Christopher
    University West, Department of Engineering Science, Division of Industrial Engineering and Management, Electrical- and Mechanical Engineering.
    Hur kan Single Minute Exchange of Die (SMED) implementeras för att minska ställtider?2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The scientific report is written at the Department of Engineering Science, University West in Trollhättan. Hofpartner AB, a steel company that develop and produce rollers, chucks and smart lifting aids, has given the assignment to investigate if their production is effective. The CEO has been informed that there is a method called SMED and would like to examine if this can be applied to Hofpartner AB production. The assignment includes an investigation of the operators working process and if the new machine can be made effective, as well as conduct a pilot study to investigate if an implementation of SMED can be applied with the intention to reduce downtimes. Literature study, interviews and observations are methods that form the bases for the degree project. The theories that have been studied have a direct link to the SMED-method. To get an overview of how effective Hofpartner AB production is, a status analysis has been performed for the categories; Machine and tools, Work place, Change between two fixtures and adjustment for processing. Several observations have been carried out regarding the operators working process, and also the availability of the capacity of the machine. Collected data has been divided into internal and external downtimes, this to be able to categorise the different phases and distinguish internal and external downtimes respectively. In order for a company to be able to use the full capacity of a machine as well as obtain an effective working process, the results must show that the internal downtimes converts to external downtimes. Based on the completed status analysis and with the support of SMED-method, the results have shown that Hofpartner AB has too long internal downtimes in their production.

  • 10619.
    Usic, Milko
    et al.
    University West, Department of Social and Behavioural Studies, Division of Social Work and Social Pedagogy.
    Sundblad, Malin
    University West, Department of Social and Behavioural Studies, Division of Social Work and Social Pedagogy.
    "Identitet Skapas I Möten Med Andra": Segregation och identitetsskapande2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med studien är att uppmärksamma och jämföra hur identitet formas utifrån elevernas kulturella och etniska bakgrund. Studien kommer att behandla 4 olika grundskolor i Trollhättans kommun, där vi vill utforska hur segregationen tar spår på ungdomars identitet. Två av skolorna har en stark majoritet på elever med invandrarbakgrund, de andra två har en stark majoritet på "svenska" elever. För att få svar på vår frågeställning " Hur påverkar segregation, kultur och etnicitet elevernas identitetskonstruktion?" intervjuar vi fyra kuratorer från fyra olika skolan för att få deras blick på hur identitet skapas av omgivningen och hur det påverkar både individen och gruppen.

    Det som studien visar är att segregationen påverkar identitetsskapandet i den valda staden och att ungdomar som växer upp i socialt utsatta områden har en större chans att bygga upp en identitet som grundar sig på maskulina, bråkiga och problematiska beteendemönster. På grund av omgivningens påverkan på identitetskonstruktionen har ungdomarna som växer upp i områden med hög kriminalitet, drogbruk och andra sociala problem hög risk att självafalla offer för dem problemen. Detta visar sig vara sant i de 4 skolor som studien behandlar, då ungdomar på de skolorna i socialtutsatta områden formar en annorlunda identitet jämfört med sina jämnåringar i andra delar av staden.

  • 10620.
    Usino, Sunday Ogheneochuko
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Surface roughness in stable and unstable machining2019Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Surface roughness is an important aspect of a machined piece and greatly influences its performance. This thesis presents the surface roughness of 7075 T651 aluminium plate of 30 mm thickness in stable and unstable machining conditions at various spindle speed and depth of cut.

    The research is conducted by generating replicas using a high-resolution silicone compound applied on the aluminium plate and therefore obtaining its surface roughness. The replicas are then measured using the Profilm 3D microscope which uses the white light interferometery (WLI), a measurement technique to acquire a 3D scan of surface roughness for the Profilm3D from the replicas.

    A study of surface roughness data generated and its representation in graphs shows that with increasing spindle speed especially at lower depth of cut the surface roughness is lower and the increase in depth of cut increase surface roughness.

  • 10621.
    Utterdahl, Linnea
    et al.
    University West, Department of Nursing, Health and Culture.
    Andersson, Jonas
    University West, Department of Nursing, Health and Culture.
    Patienters upplevelser av sjuksköterskans bemötande på akutmottagningen2011Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Background: The patient meets nurses in the emergency department that provide both nursing and has medical skills. The care that the patients are receiving should be individually adjusted. The care is shaped by the individual meeting with the patient according to the nursing theorist Orlando. There are large variations between the number of patients in an emergency department and it sets high demands on the staff, both physically and mentally. When the emergency department is highly loaded there is a priority for medical care and psycho-social and aesthetic aspects will have to wait. It´s often an impossibility to be able to sit down with the individual patient and talk for a while.

    Aim: The purpose of this study was to describe the patient´s perceptions of nurse’s treatment at an emergency department.

    Method: Ten scientific papers from the years 1999 – 2010 have been used in our literature review in which the similarities and differences are compared.

    Result: The result of the analysis resulted in three titles, environment affects the integrity, that patients well-being are satisfied and the nurse information affects patient’s experience.

    Conclusion: Whether the communication turned out well between patient and nurse influenced how the patient experienced the visit at the emergency department. 

  • 10622.
    Uvalic, Mathea
    et al.
    University West, Department of Nursing, Health and Culture, Divison of Caring Sciences, undergraduate level.
    Walter, Emmi
    University West, Department of Nursing, Health and Culture, Divison of Caring Sciences, undergraduate level.
    Alzheimers sjukdom: anhörigas känslor vid en förändrad livssituation2013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Alzheimer's disease is the most common form of dementia. The individual who fall ill can be in an age between 40-65 years old. When dementia affects individuals at this age, many relatives take their responsibility for taking care of them at home for a long time.

    The aim of this study was to illustrate emotions relatives experienced when a close family member's suffering from Alzheimer's disease. The study was intended to show relatives emotions, and therefor four self-biographies were chosen to read. The method used to analyze was a narrative literature review. The emotions that emerged among the relatives who cared for their close family member were grief, tiredness, impotency, fear and frustration, sense of duty and hope. These were divided into six categories with zero to three subcategories. When a close family member suffers from Alzheimer's disease, life changes even for the relative. The nurse role is important in this context to support and provide tools for the relative to be able to handle the situation.

  • 10623.
    Uvehammar, Marianne
    University West, Department of Social and Behavioural Studies.
    The impact of linguistic strategies in political debate: a linguistic discourse analysis of the first Bush and Kerry presidential debate, 20042005Independent thesis Basic level (degree of Bachelor)Student thesis
  • 10624.
    Uvnäs-Moberg, Kerstin
    et al.
    University of Agriculture (SLU), Uppsala, Sweden.
    Ekström-Bergström, Anette
    University West, Department of Health Sciences, Section for nursing - graduate level. University of Skövde, School of Health and Education, Skövde, Sweden.
    Berg, Marie
    University of Gothenburg, Institute of Health and Care Sciences, Gothenburg, Sweden.
    Buckley, Sarah
    The University of Queensland, School of Public Health, Brisbane, Australia..
    Pajalic, Zada
    Oslo and Akershus University College of Applied Sciences, Faculty of Health Sciences Oslo, Norway.
    Hadjigeorgiou, Eleni
    University of Technology, Faculty of Health Sciences, Cyprus, Limassol, Cyprus.
    Kotłowska, Alicja
    Medical University of Gdańsk, Faculty of Health Sciences with Subfaculty of Nursing and Institute of Maritime and Tropical Medicine, Gdańsk, Poland.
    Lengler, Luise
    Midwifery Research and Education Unit, Hannover Medical School, Hannover, Germany.
    Kielbratowska, Bogumila
    Medical University of Gdańsk, Faculty of Medical Sciences, Gdańsk, Poland.
    Leon-Larios, Fatima
    University of Seville, Faculty of Nursing, Physiotherapy and Podiatry, Seville, Spain.
    Magistretti, Claudia Meier
    Lucerne University of Applied Sciences and Arts, Department of Social Work Center for Health Promotion and Social Participation, Luzern, Switzerland.
    Downe, Soo
    University of Central Lancashire, Research in Childbirth and Health (ReaCH) group, Preston, UK.
    Lindström, Bengt
    Norwegian University of Science and Technology, Trondheim, Norway.
    Dencker, Anna
    University of Gothenburg, Institute of Health and Care Sciences, Gothenburg, Sweden .
    Maternal plasma levels of oxytocin during physiological childbirth: a systematic review with implications for uterine contractions and central actions of oxytocin2019In: BMC Pregnancy and Childbirth, ISSN 1471-2393, E-ISSN 1471-2393, Vol. 19, no 1, article id 285Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Oxytocin is a key hormone in childbirth, and synthetic oxytocin is widely administered to induce or speed labour. Due to lack of synthetized knowledge, we conducted a systematic review of maternal plasma levels of oxytocin during physiological childbirth, and in response to infusions of synthetic oxytocin, if reported in the included studies.

    METHODS: An a priori protocol was designed and a systematic search was conducted in PubMed, CINAHL, and PsycINFO in October 2015. Search hits were screened on title and abstract after duplicates were removed (n = 4039), 69 articles were examined in full-text and 20 papers met inclusion criteria. As the articles differed in design and methodology used for analysis of oxytocin levels, a narrative synthesis was created and the material was categorised according to effects.

    RESULTS: Basal levels of oxytocin increased 3-4-fold during pregnancy. Pulses of oxytocin occurred with increasing frequency, duration, and amplitude, from late pregnancy through labour, reaching a maximum of 3 pulses/10 min towards the end of labour. There was a maximal 3- to 4-fold rise in oxytocin at birth. Oxytocin pulses also occurred in the third stage of labour associated with placental expulsion. Oxytocin peaks during labour did not correlate in time with individual uterine contractions, suggesting additional mechanisms in the control of contractions. Oxytocin levels were also raised in the cerebrospinal fluid during labour, indicating that oxytocin is released into the brain, as well as into the circulation. Oxytocin released into the brain induces beneficial adaptive effects during birth and postpartum. Oxytocin levels following infusion of synthetic oxytocin up to 10 mU/min were similar to oxytocin levels in physiological labour. Oxytocin levels doubled in response to doubling of the rate of infusion of synthetic oxytocin.

    CONCLUSIONS: Plasma oxytocin levels increase gradually during pregnancy, and during the first and second stages of labour, with increasing size and frequency of pulses of oxytocin. A large pulse of oxytocin occurs with birth. Oxytocin in the circulation stimulates uterine contractions and oxytocin released within the brain influences maternal physiology and behaviour during birth. Oxytocin given as an infusion does not cross into the mother's brain because of the blood brain barrier and does not influence brain function in the same way as oxytocin during normal labour does.

  • 10625.
    Uzun, Yusuf
    University West, Department of Economics and IT, Division of Business Administration.
    The impact of culture on business negotiations between Swedish and Turkish counterparts: seen from the viewpoint of Swedish businessman2014Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    As business expand globally, international negotiations has become daily activity rather than an occasional event. Negotiations across borders occur every day in both SME´s and MNE´s in order to develop specific strategies for exporting, importing, setting up joint ventures or managing subsidiaries in foreign countries. Successful collaboration of any kind requires a willingness to engage. However, the majority of many negotiation efforts fail even though both sides want to reach a successful collaboration. The failures are usually caused by cultural aspects rather than economic or legal.

    The purpose of this research is to investigate the cultural factors that have influence on cross-cultural negotiations between Swedish and Turkish businessmen. A hermeneutic and qualitative approach was used and three deep interviews with Swedish businessmen with vast experience were conducted.

    There are a variety of cultural factors that are considered to affect negotiators in their work. With the results provided by the interviews, it is found that the most important affecting factor when it comes to do business with Turkish businessmen are personal relationships. It is found that lack of personal relations in Turkey could get one in inferior negotiation position. It is also found that non-verbal communications are important since Turkish businessmen extensively use it and lack of knowledge in understanding non-verbal communications can lead to misunderstandings and hamper the negotiation. It is also found that norms and formalities plays a vital role since this study shows that improper clothing and improper way to address people can be insulting for the Turkish counterpart and can therefore affect the negotiations and further lead to unwanted effects

  • 10626.
    Vaern, Johan
    University West, Department of Engineering Science, Division of Computer and Electrical Engineering.
    En jämförelse av hybridapplikationer utvecklade i Intel XDK2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today, when accessing information and services on the Internet on desktop computers it has become the norm to use web browsers. In mobile devices the situation is different, where the users prefer dedicated applications. The market for mobile devices is fragmented with many different operating systems and manufacturers. Because of this fragmentation each application needs to be developed in different versions Lately, methods have been introduced for developing applications with a shared code base; this technology makes it possible to run an application on any type of operating system. This type of application is often called a hybrid application, and uses web technologies such as HTML5, JavaScript and CSS3. To be able to access the native features of the device it is necessary to use API libraries.

    Intel XDK was introduced in 2013 and is a development environment for hybrid applications, it gives developers several opportunities to choose from different runtime environments, API-libraries and frameworks for design of user interfaces. With the help of benchmark tests this report compares the performance of the different options available.

    The report also presents recommendations on which options to use for development of applications targeting the Android OS using Intel XDK 

  • 10627. Vahlne Westerhäll,, Lotta
    Arbets(o)förmåga.: Ur ett mångdisciplinärt perspektiv2008Collection (editor) (Other academic)
  • 10628.
    Vajta, Anna
    et al.
    University West, Department of Nursing, Health and Culture, Divison of Caring Sciences, undergraduate level.
    Johansson, Sofia
    University West, Department of Nursing, Health and Culture, Divison of Caring Sciences, undergraduate level.
    Jag älskar dig alltid, men inte allt du gör.: Föräldrars erfarenheter av att ha ett barn med ADHD med eller utan hyperaktivitet2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Background:

    Having a child with ADHD is exhausting for parents and other family members. The child can take a dominant role against the parents and any siblings may receive less attention. The nurse's response is relevant in meeting with parents because it can elevate or destroy the relationship between her, the parents and the child. Aim: Parent's experiences of having a child with ADHD with or without hyperactivity. Method: This study was based on narratives, which in this case means an analysis of biographies. Four biographies were analyzed by using Dahlborg-Lyckhage's (2012) description of analysis of narratives. Results: The study resulted in five categories and twelve subcategories. The result shows that parents' experiences of having a child with ADHD is emotional. Procedures in life is important to be able to deal with everyday-situations. Likewise, the social situations between parents and society are complicated to deal with. Conclusion: This study has provided information about parent's experiences of having a child with ADHD with or without hyperactivity. Parents need help and support from both caregivers and relatives. Procedures are important to get an easier life. The parents are living with many different emotions. The contact with the school, health care and other adults is complicated. Time for relaxation is important to recover. Treatment with stimulant medication is perceived as a dilemma. This study can contribute to better understanding in encounters with these parents.

  • 10629.
    Vakola, Josefin
    University West, Department of Economics and IT, Division of Business Administration.
    Belöningssystem: En kvalitativ fallstudie från ett medarbetarperspektiv om systemets utformning och dess komponenter samt medarbetarnas delaktighet och motivation2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Organizations today should design and implement a well-functioning reward system, however, it is not so simple.

    The problem lies in combining the different components available in a reward system in an efficient way, both for the organization´s best and for employee motivation. Therefore the purpose of the essay is to describe and highlight how the reward system is designed and how it is used in a particular organization, the way in which the employees may participate in the design process of the reward system and if the reward system is designed so that employees are motivated to perform in their daily work. As the method a qualitative approach has been used in which a case study designed with 17 interviews that form the basis of empirical chapter. A hermeneutic approach has been used since the purpose of the study was to interpret, understand and describe phenomena and understand the context. The study theoretical chapter is divided into three main areas, namely, motivation, reward system and its components and employee participation. In each area, presented the relevant information related to the reward system and its function in the organization. Also some theories presented, mainly in connection with motivation.

    A detailed

    analysis was made on the results that were produced through the interviews and information from the theory chapter. As there was no precise answer to how an organization motivates their employees, how a reward system should be designed by the various components and how much and in what ways employees should be involved in the design process, it is up to the organization itself to decide. Through the interviews, it revealed that the studied organization had designed four different reward systems to motivate employees to accurate and efficient performance in their daily work. The organization had three of the reward system focused on group-based assessment, formal evaluation, performance measurement, and both financial and non-financial rewards. In one of the rewards system was the focused on individual based assessment, subjective evaluation, performance measurement and financial reward. This shows the variety and a willingness to motivate as many employees as the organization can only be through different designs on their reward systems. The conclusion to this study is that the studied organization has managed to design and implement reward systems where employees feel motivated to perform to the organization's goals. The organization has succeeded for instance because they allow employees to be involved in the design process, there is a good dialogue between managers and employees, managers gives employees praise and show appreciation. Other factors are that they have chosen to focus on solidity, morale, fellowship, and especially on the long term. The organization is putting its employees first.

  • 10630.
    Vaktel, Andreas
    et al.
    University West, Department of Economics and Informatics.
    Ohlsson, Johannes
    University West, Department of Economics and Informatics.
    Webbdistribuerad pedagogisk multimediaproduktion: en studie i designarbetets tvärvetenskapliga natur2005Independent thesis Advanced level (professional degree)Student thesis
  • 10631.
    Valdebenito Valle, Victoria
    University West, Department of Technology, Mathematics and Computer Science.
    Ombildning av hyresrätter till bostadsrätter2004Independent thesis Advanced level (professional degree)Student thesis
  • 10632.
    Vales, Carlos
    University West, Department of Social and Behavioural Studies, Division of Social Work and Social Pedagogy.
    Fältsekreterares legitimitet till fältet: En etnografisk studie om förhandling i det offentliga rummet2018Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The background of the study is that there is limited research in the child- and youth research field, on the interaction between youth and professionals in the public space. Previous research in the field have been focused on stories from informants, but few studies have been based on an ethnographic approach. Observing how the interaction between young people and out-reach workers develops in public spaces to achieve legitimacy to the field is very limited. Promoting youth agency in the interaction has been guiding in this study, as previous fieldwork research has been based on the professional's point of view. The purpose of the study is to describe, analyze and interpret how out-reach workers interact with young people in the public space. Through an ethnographic study show, not only what is said but also observe what is happening in the interaction. The relevant issues for this study are the following ones: How do out-reach workers create legitimacy in the field? What strategies are out-reach workers using to make contact with young people while at the same time preserving their agency? And, from a young person’s perspective, which characteristics are important to have as an out-reach worker? The study is based on participative observations and informal conversations with young people and outreach worker in a selected municipality. Through participative observation we can find ourselves in public spaces with outreach workers and young people and observe what is really happening in the interaction between them. By interpretation, the researcher is able to capture the subjective importance of social action. All in all, thirteen field notes were made. The scope of these field notes varied between some preliminary notes such as support words and mental notes, to later complete full field notes at the end of the day. The interpreting process through the hermeneutic circle has been helpful for the experience-near interpretation of the individual's way of thinking, but also the way of acting. The result shows that the creation of legitimacy in the field requires that professionals through a social pedagogical approach act in public space and interact with the young people in the context in which they are. By having knowledge of young people, the outreach worker convey confidence and security. By appearing in the public space, outreach worker exercise a form of power, which includes both controlling and helping dimensions. The outreach workers strategies for creating legitimacy often require trustful relationships with young people.

  • 10633.
    Vali, Akram
    University West, Department of Informatics and Mathematics.
    På väg mot det papperslösa sjukhuset: med hjälp av Melior - elektronisk patientjournal2003Independent thesis Advanced level (professional degree)Student thesis
  • 10634.
    Valiente Bermejo, María Asunción
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Guia de les escultures de Mollet del Vallès: Metalls, tècniques i curiositats2015 (ed. 1)Book (Other (popular science, discussion, etc.))
    Abstract [en]

    This publication presents a comprehensive study on the current 35 metal artwork pieces located in public spaces of Mollet del Vallès. The sculptures are described from a technical perspective: metallic alloys, joining techniques and protective mechanisms against corrosion are described. However, this research also reveals interesting curiosities and secrets hidden by these sculptures. The information is organised in clear datasheets, where the technical details from the experimental observation and from the official technical project reports are summarised. The symbolisms, anecdotes and curiosities included in this work were gathered during fruitful conversations with authors, authorities and companies involved in the execution of the metal works. The main aim of this work is to invite the reader to stroll into town, to rediscover our heritage, to appreciate it and to make new generations love it. 

  • 10635.
    Valiente Bermejo, María Asunción
    University West, Department of Engineering Science, Division of Welding Technology.
    Teaching Welding with a Flipped Classroom Approach2019In: Welding Journal, ISSN 0043-2296, Vol. 98, no 9, p. 42-45Article in journal (Refereed)
  • 10636.
    Valiente Bermejo, María Asunción
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    DebRoy, Tarasankar
    University Park, Department of Materials Science and Engineering, The Pennsylvania State University, State College PA 16801, USA.
    Hurtig, Kjell
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Karlsson, Leif
    University West, Department of Engineering Science, Research Enviroment Production Technology West.
    Svensson, Lars-Erik
    University West, Department of Engineering Science, Division of Production Engineering.
    Towards a Map of Solidification Cracking Risk in Laser Welding of Austenitic Stainless Steels2015In: Physics Procedia, ISSN 1875-3892, E-ISSN 1875-3892, Vol. 78, p. 230-239Article in journal (Refereed)
    Abstract [en]

    In this work, two series of specimens with Hammar and Svensson's Cr- and Ni-equivalents (Creq+Nieq) = 35 and 45 wt% were used to cover a wide range of austenitic grades. These were laser welded with different energy inputs achieving cooling rates in the range of 103 °C/s to 104 °C/s. As high cooling rates and rapid solidification conditions could favour fully austenitic solidification and therefore raise susceptibility to solidification cracking, the solidification modes of the laser welded specimens were compared to the ones experienced by the same alloys under arc welding conditions. It was found that high cooling rates experienced in laser welding promoted fully austenitic solidification for a wider range of compositions, for example specimens with (Creq+Nieq) = 35% under arc welding cooling conditions at 10 °C/s showed fully austenitic solidification up to Creq/Nieq = 1.30, whilst the same specimens laser cooled at 103 °C/s showed fully austenitic solidification up to Creq/Nieq = 1.50 and those cooled at 104 °C/s showed it up to Creq/Nieq = 1.68. Therefore, high cooling rates extended the solidification cracking risk to a wider range of Creq/Nieq values. This work also compares the cooling rates experimentally determined by thermocouples to the computed cooling rates calculated by a highly-advanced computational model. The distance between the thermocouple's wires and the thermal resistance of thermocouples together with the small size of the weld pools proved to be practical limitations in the experimental determination of cooling rates. However, an excellent agreement was found between computed and experimental solidus isotherms at high energy input settings. For low energy input settings cooling rate was in the order of magnitude of 104 °C/s, whilst for high energy input settings cooling rate was found to be in the order of magnitude of 103 °C/s.

  • 10637.
    Valiente Bermejo, María Asunción
    et al.
    University West, Department of Engineering Science, Division of Welding Technology.
    Hurtig, Kjell
    University West, Department of Engineering Science, Division of Welding Technology.
    Eyzop, Daniel
    Outokumpu Stainless AB, Avesta R&D Center, 774 41 Avesta, Sweden.
    Karlsson, Leif
    University West, Department of Engineering Science, Division of Welding Technology.
    A New Approach to the Study of Multi-Pass Welds–Microstructure and Properties of Welded 20-mm-Thick Superduplex Stainless Steel2019In: Applied Sciences, E-ISSN 2076-3417, Vol. 9, no 6, article id 1050Article in journal (Refereed)
    Abstract [en]

    Type 2507 superduplex stainless steel 20 mm in thickness was multi-pass-welded with Gas Metal Arc Welding (GMAW) and Flux-Cored Arc Welding (FCAW) processes. Recommended and higher arc energies and inter-pass temperatures were used. Thermal cycles were monitored using a recently developed procedure involving the successive instrumentation of the multi-pass welds, pass by pass, by addition of thermocouples in each weld pass. The repeatability of temperature measurements and survival rate of more than 90% of thermocouples confirmed the reliability of the procedure. Reheating by subsequent passes caused a progressive increase in the austenite content of the weld metal. The as-deposited GMAW passes with higher-than-recommended arc energy showed the lowest presence of nitrides. Therefore, the cooling rate—and not the time exposed at the critical temperature range—seems to be the key factor for nitride formation. The welding sequence layout also plays an important role in the distribution of secondary phases. A larger amount and concentration of secondary austenite and σ-phase was found for a larger number of subsequent passes in the immediate vicinity of a specific weld pass. The impact toughness exceeded requirements for all welds. Differences in absorbed energies were related to the amount of micro-inclusions found with the FCAW weld showing the lowest absorbed energies and highest amount of micro-inclusions. Pitting corrosion preferentially initiated in locations with secondary austenite and σ-phase. However, in the absence of these secondary phases, the HAZ containing nitrides was the weakest location where pitting initiated. The results of this work have implications on practical welding for superduplex stainless steels: the current recommendations on maximum arc energy should be revised for large thickness weldments, and the importance of the welding sequence layout on the formation of secondary phases should be considered.

  • 10638.
    Valiente Bermejo, María Asunción
    et al.
    University West, Department of Engineering Science, Division of Welding Technology.
    Hurtig, Kjell
    University West, Department of Engineering Science, Division of Welding Technology.
    Hosseini, Vahid
    University West, Department of Engineering Science, Division of Welding Technology.
    Karlsson, Leif
    University West, Department of Engineering Science, Division of Welding Technology.
    Svensson, Lars-Erik
    University West, Department of Engineering Science, Division of Welding Technology.
    Monitoring Thermal Cycles in Multi-pass Welding2016In: The 7th International Swedish Production Symposium, SPS16, Conference Proceedings: 25th – 27th of October 2016, Swedish Production Academy , 2016, p. 1-5Conference paper (Refereed)
    Abstract [sv]

    Differently from any previous investigation in welding, this research work presents a novel development that allows temperature to be measured and recorded simultaneously with up to 32 thermocouples indifferent locations of a welding joint. Four experiments were designed to optimise the measurement technique by comparing the performance of three types of thermocouples (K, N, C) insulated with different materials and varying the insertion technique of the thermocouples in the joint. Results showed that type-K thermocouple had the best performance and proved that glass fibre insulation provided better protection than Inconel. The optimised measurement procedure developed in this work enables to monitor the thermal cycles in multi-pass welds. That information is essential in multi-pass welding of materials such as super duplex stainless steels, carbon steels or nickel alloys, as heating them repeatedly makes them susceptible to the formation of brittle phases and in turn it influences their mechanical and corrosion properties. This technique could be really important for future applications such as temperature modellingor prediction of mechanical properties and microstructure in relation to the thermal cycle experienced by alloys susceptible to the formation of undesirable phases.

  • 10639.
    Valiente Bermejo, María Asunción
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Karlsson, Leif
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    DebRoy, Tarasankar
    Pennsylvania State University.
    Influence of low energy laser welding on solidification and microstructure of austenitic stainless steel welds2013In: 14th NOLAMP Conference: The 14th Nordic Laser Materials Processing Conference, August 26th – 28th 2013, Gothenburg, Sweden / [ed] Alexander Kaplan, Hans Engström, Luleå: Luleå University of Technology, 2013, p. 3-14Conference paper (Refereed)
    Abstract [en]

    Primary austenitic solidification is related to increased hot cracking susceptibility in welding of austenitic stainless steels. It is also recognised that high cooling rates and rapid solidification conditions, like those achieved in laser beam welding (LBW), increase the stability of austenite versus ferrite as the primary solidification phase. Knowledge about the solidification mode under LBW conditions is therefore of utmost importance. A series of austenitic stainless steel alloys were prepared using an electric arc furnace and cooled at a rate of 10 ºC/s. The overall alloying composition was kept constant at [Cr eq+Nieq] = 40 wt% while changing the Cr eq/Nieq ratio from 1.52 to 1.84. These alloys were then laser welded using a continuous wave ytterbium fibre laser at two different energy input levels. Cooling rates were experimentally determined to be in the range of 10 3 ºC/s to 104 ºC/s and the values were confirmed by computational modelling. The compositional border between primary austenitic and primary ferritic solidification was found to shift to higher Cr eq/Nieq values at higher cooling rates. However, all the alloys showed coexistence of regions of primary austenitic and primary ferritic solidification for both laser settings although ustenite tended to more abundant at higher cooling rates. Austenite content and refinement of microstructure is discussed in terms of effects of cooling rate on solidification behaviour and solid state transformations.

  • 10640.
    Valiente Bermejo, María Asunción
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Karlsson, Leif
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Svensson, Lars-Erik
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Hurtig, Kjell
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Optimising Quality and Productivity in Welding of Duplex and Superduplex Stainless Steels2014In: Proceedings of the 6th International Swedish Production Symposium 2014 / [ed] Stahre, Johan, Johansson, Björn & Björkman, Mats, 2014, p. 1-7Conference paper (Refereed)
    Abstract [en]

    The aim of this work was to study the influence of shielding gases and welding positions on properties of duplex and superduplex stainless steel circumferential pipe welds. Corrosion resistance, microstructural features and weld defects were assessed and related to the welding procedures. Horizontal and vertical upward welding positions produced high quality welds. However, welding in the overhead position resulted in less good results in terms of porosity and corrosion resistance. Shielding gases containing 30% helium showed best results, whilst using a mixture Ar+2%CO2 resulted in undercuts and porosity in all welding positions.

  • 10641.
    Valiente Bermejo, María Asunción
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Karlsson, Leif
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Svensson, Lars-Erik
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Hurtig, Kjell
    University West, Department of Technology, Mathematics and Computer Science, Division for Mechanical Engineering.
    Rasmuson, H.
    ESAB AB, Göteborg, Sweden.
    Frodigh, M.
    Sandvik Materials Technology, Sandviken, Sweden.
    Bengtsson, P.
    AGA Gas AB, Lidingö, Sweden.
    Effect of shielding gas on welding performance and properties of duplex and superduplex stainless steel welds2015In: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 59, no 2, p. 239-249Article in journal (Refereed)
    Abstract [en]

    The influence of shielding gases on welding performanceand on properties of duplex and superduplex stainlesssteel welds was studied. Using argon as the reference gas,helium, nitrogen and carbon dioxide were added and fivemixtures evaluated. Bead-on-plate welds and circumferentialpipe welds were produced using mechanisedGMAwelding inthe downhand position. Welding performance, corrosion resistance,mechanical properties, microstructural features andweld imperfections were assessed and related to the shieldinggas. Shielding gases containing 30 % helium showed excellentresults; whilst pure argon showed unstable arc and poorweld pool fluidity and Ar+2 %CO2 resulted in underfill andporosity. Mixtures containing helium resulted in higher ductilitywelds and higher impact toughness values than weldsproduced with Ar+2 %CO2. Sound and balanced duplexmicrostructures free from intermetallics were found with suitableferrite contents for all the shielding gases studied. All theduplex pipe welds passed the corrosion test regardless of theshielding gas used, and the best results in the corrosion test forsuperduplex pipe welds were found when using Ar+30 %He+0.5 %CO2+1.8 %N2 as shielding gas.

  • 10642.
    Valiente Bermejo, María Asunción
    et al.
    University West, Department of Engineering Science, Division of Welding Technology.
    Karlsson, Leif
    University West, Department of Engineering Science, Division of Welding Technology.
    Svensson, Lars-Erik
    University West, Department of Engineering Science, Division of Welding Technology.
    Hurtig, Kjell
    University West, Department of Engineering Science, Division of Welding Technology.
    Rasmuson, H.
    ESAB AB, Goteborg Svezia, Sweden.
    Frodigh, M.
    Sandvik Materials Technology, Sandviken, Svezia, Sweden.
    Bengtsson, P.
    AG A Gas AB, Germany .
    Influenza del gas di protezione sul comportamento e le proprietà  di giunti sa dati di acciai duplex e superduplex: Effect of shielding gas on welding performance and properties of duplex and superduplex stainless steel welds2016In: Rivista Italiana della Saldatura, ISSN 0035-6794, Vol. 68, no 5, p. 635-650Article in journal (Other academic)
    Abstract [en]

    The influence of shielding gases on welding performance and on properties of duplex and superduplex stainless steel welds was studied. Using argon as the reference gas, helium, nitrogen and carbon dioxide were added and five mixtures evaluated. Bead-on-plate welds and circumferential pipe welds were produced using mechanised GMA welding in the downhand position. Welding performance, corrosion resistance, mechanical properties, microstructural features and weld imperfections were assessed and related to the shielding gas. Shielding gases containing 30% helium showed excellent results; whilst pure argon showed unstable arc and poor weld pool fluidity and Ar + 2% CO2resulted in underfill and porosity. Mixtures containing helium resulted in higher ductility welds and higher impact toughness values than welds produced with Ar + 2% CO2. Sound and balanced duplex microstructures free from intermetallics were found with suitable ferrite contents for all the shielding gases studied. All the duplex pipe welds passed the corrosion test regardless of the shielding gas used, and the best results in the corrosion test for superduplex pipe welds were found when using Ar + 30%He + 0.5% CO2+ 1.8% N2as shielding gas.

  • 10643.
    Valiente Bermejo, María Asunción
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Karlsson, Leif
    University West, Department of Engineering Science, Divison of Natural Sciences, Surveying and Mechanical Engineering.
    Svensson, Lars-Erik
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Hurtig, Kjell
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Rasmuson, Helene
    ESAB AB, Göteborg, Sweden.
    Frodigh, Mette
    Sandvik Materials Technology, Sandviken, Sweden .
    Bengtsson, Per
    AGA Gas AB, Lidingö, Sweden.
    Effect of welding position on properties of duplex and superduplex stainless steel circumferential welds2015In: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 59, no 5, p. 693-703Article in journal (Refereed)
    Abstract [en]

    The influence of welding position on properties ofduplex and superduplex stainless steel welds was studied. Circumferential pipe welds were produced using mechanised gasmetal arc welding in flat position, vertical up position and overhead position. Dilution, corrosion resistance, mechanical properties, microstructural features and weld imperfections were assessed and related to the welding position. Welds produced in flat and vertical up positions were less likely to produce porosity than those welded in overhead position, whilst underfill was not observed in overhead position welds. All the duplex pipe welds passed the corrosion test regardless of the welding position and showed sound microstructures. Under fixed arc energy conditions, welds produced in vertical up position showed the lowest dilution values whilst welds in flat position showed the highest. Excellent impact toughness values and cross tensile values were found regardless of the welding positions. Whenever possible, flat position is recommended as welds showed less proneness to porosity. Vertical up position is recommended as the second best choice.

  • 10644.
    Valiente Bermejo, María Asunción
    et al.
    University West, Department of Engineering Science, Division of Welding Technology.
    Wessman, Sten
    Swerim AB, Kista, Sweden.
    Computational thermodynamics in ferrite content prediction of austenitic stainless steel weldments2019In: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 63, no 3, p. 627-635Article in journal (Refereed)
    Abstract [en]

    In this paper, four computational approaches using Thermo-Calc and DICTRA have been used to calculate the ferrite content of a set of austenitic stainless steel welds with different solidification modes and ferrite contents. To evaluate the computational approaches, the calculations were compared to the experimental results. It was found that for each solidification mode, there is one computational approach that predicts ferrite with better accuracy. For ferritic-austenitic alloys, the best accuracy is obtained when considering the peritectic model, with deviations of 1.2–1.4% ferrite. In the case of austenitic-ferritic alloys, the solidification analysed through the eutectic approach showed an accuracy of 0.6–1.6% ferrite, whilst in alloys with fully ferritic solidification, starting calculations, not from the liquid state but from fully ferritic below solidus, was the best approach, showing 2.3% ferrite deviation from the experimental measurements. Computational thermodynamics has proved to be a promising tool to explore simulation and calculation of ferrite content phase fractions in welding. However, further investigation is still needed to correlate the real microstructural features with the computational parameter “cell size”. The feasibility and accuracy of computational thermodynamics when predicting ferrite in low-heat-input welding processes such as laser welding is also another aspect for additional investigation.

  • 10645.
    Valiente Bermejo, María Asunción
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Zhang, Zhuyao
    Metrode Products Limited, Hanworth Lane, Chertsey, Surrey.
    Relevance and limitations of arc furnace casting in welding research2015In: International Journal of Cast Metals Research, ISSN 1364-0461, E-ISSN 1743-1336, Vol. 28, no 2, p. 97-104Article in journal (Refereed)
    Abstract [en]

    The arc furnace melting technique is widely used for positive material identification in the industry of welding consumable manufacturing. It is also a convenient method for sample preparations ofvarious pre-design chemical compositions for investigations on solidification, phase transformationand microstructure of different alloys. However, up to now, welding research works using the arc furnace melting technique did not report to follow any international standard. This is the first time that an international standard involving arc furnace casting is discussed and evaluated to be applied in the welding research field. In this paper, the specimens obtained with the ASTM E1306-94 standard are assessed, and some suggestions are proposed for modification and improvement of the standard, like adding some intermediate steps including the turning over ofthe specimen and an extra melting. By adopting those proposals in the procedure, cast samples with complete melting and chemical composition homogeneity were achieved.

  • 10646.
    Valjevac, Adisa
    et al.
    University West, Department of Social and Behavioural Studies, Division of Social Pedagogy and Sociology.
    Bladh, Stefan
    University West, Department of Social and Behavioural Studies, Division of Social Pedagogy and Sociology.
    "HBTQ-ungdom, den hårda skolan"2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 10647. Valleti, K.
    et al.
    Jyothirmayi, A.
    Ramakrishna, M.
    Joshi, S. V.
    Influence of substrate temperature and bias voltage on properties of chromium nitride thin films deposited by cylindrical cathodic arc deposition2011In: Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films, Vol. 29, no 5, article id 051515Article in journal (Refereed)
    Abstract [en]

    Chromium nitride (CrN) thin films have been deposited on high speed steel (HSS) substrates using rotating cylindrical cathodic arc deposition technique and the influence of substrate temperature (TSub) and bias voltage (VSub) on the physical/mechanical and corrosion resistance properties of the films comprehensively investigated. An increase in TSub was found to significantly influence the phase composition of films, which changed from a mixture of Cr CrxN CrN to predominantly CrN. This was also accompanied by an increase in droplet formation and columnar grain size. With increase in TSub over the range investigated (230 °C to 500 °C), an increase in adhesion strength by nearly 30 was observed. In contrast, change in VSub from -50 to -150 V resulted in the growth of highly dense (111) oriented CrN thin films but with relatively little change in phase constitution, adhesion strength or microdroplet formation. A change in TSub from 230 °C to 500 °C was accompanied by a nearly 50 fall in corrosion resistance, plausibly due to the concomitant decrease in pure Cr phase content and increase in macroscopic defect concentration with increase in TSub. In view of the above, CrN thin films deposited using cylindrical cathodic arc deposition technique yield better corrosion resistance and mechanical properties when grown at low TSub. © 2011 American Vacuum Society.

  • 10648. Valleti, K.
    et al.
    Murali Krishna, D.
    Joshi, S. V.
    Functional multi-layer nitride coatings for high temperature solar selective applications2014In: Solar Energy Materials and Solar Cells, Vol. 121, p. 14-21Article in journal (Refereed)
    Abstract [en]

    A solar-selective functional multi-layered coating for high temperature applications has been developed on copper and stainless steel substrates using an industrially viable cathodic arc physical vapor deposition technique. The selective coating was formulated in such a way that the constituent functional layers are mainly high temperature stable nitride materials which are also hard and capable of imparting protection against wear. A multi-layer structure comprising TiAlCrN as IR reflector, TiAlN as absorber and AlSiN as anti-reflective layer was found to exhibit promising results. The stacking of these three materials with appropriate thickness in a systematic manner, viz. Cu/TiAlCrN/TiAlN/AlSiN with high Cr and Al contents in TiAlCrN and TiAlN layers, respectively, yielded high absorptivity (αAM1.5=0.91) and low emissivity (ε=0.07) values corresponding to an attractive optical selectivity (α/ε) of 13. The open air high temperature performance of the optimized multi-layer structure was also investigated in the temperature range 27-700 C and the stability of the coatings at high temperatures with respect to optical properties was established. © 2013 Elsevier B.V.

  • 10649. Valleti, K.
    et al.
    Rejin, C.
    Joshi, S. V.
    Factors influencing properties of CrN thin films grown by cylindrical cathodic arc physical vapor deposition on HSS substrates2012In: Materials Science and Engineering A, Vol. 545, p. 155-161Article in journal (Refereed)
    Abstract [en]

    The present study deals with growth of well-adherent and tough CrN thin films by cylindrical cathodic arc physical vapor deposition. The influence of substrate preparation parameters and deposition variables on film properties has been systematically investigated. The adhesion strength, hardness and crack propagation resistance (CPR) of the films were evaluated for different processing conditions. High substrate hardness and low substrate surface roughness were found to be conducive for obtaining well-adherent films. Cr ion etching was found to yield superior film properties, with the duration of etching also being a key determining factor. The nitrogen partial pressure employed during film deposition was noted to significantly influence the phase combination of the CrN x films as well as the stress levels in the deposited films. In case of multilayer CrN x films, alternating high toughness-low toughness layers were found to yield encouraging properties, with CPR values markedly higher than those obtained in mono-layer CrN x films, with no compromise in either hardness or adhesion strength. © 2012 Elsevier B.V.

  • 10650. Valleti, K.
    et al.
    Subrahmanyam, A.
    Joshi, S. V.
    Growth of nano crystalline near α phase tantalum thin films at room temperature using cylindrical magnetron cathode2008In: Surface and Coatings Technology, Vol. 202, no 14, p. 3325-3331Article in journal (Refereed)
    Abstract [en]

    The much desired α (bcc) Tantalum (Ta) thin films are grown at room temperature using a newly designed cylindrical magnetron cathode (with rotating magnets geometry) with pulsing power. The new design has facilitated oblique incidence of adatoms. The electron temperature of the plasma has been enhanced due to the pulsing frequency (100 kHz). These two factors: oblique incidence of adatoms and enhanced electron temperature are presumed to be responsible for the formation of α phase Ta thin films at room temperature. The volume fractions of α and β phases have been evaluated from the X-ray data. The effect of pulsing (0-100 kHz) on the structural, electrical and mechanical properties of Ta thin films has also been studied. With the pulsing frequency, the lattice spacing in the Ta thin films increases (due to the incorporated argon) resulting in an increase in the compressive stress. Up to 75 kHz of the pulsing frequency, the Ta films formed are in the β phase (tetragonal) with ~ 13 nm grain size. At 100 kHz pulsing, the change in the surface morphology also indicates the phase change in the film. © 2008 Elsevier B.V. All rights reserved.

210211212213214215216 10601 - 10650 of 11191
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf