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  • Gunneström, Klara
    et al.
    Linköping University, Department of Management and Engineering, Malmstens Linköping University.
    Torell Nordgren, Elsa
    Linköping University, Department of Management and Engineering, Malmstens Linköping University.
    Vulst på ram nr. 1-7: En formsökande studie i tapetserarhantverket2019Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [sv]

    Vi utforskar vulsten, ett återkommande moment för möbeltapetserare, och från ett nytt och ej funktionsgivet sätt placerar vi den på ram för alla att se.

    När en tapetserare ska ta sig an momentet vulst så utgår hen från hur en, i möbelsammanhang, stomme är utformad och vilken sorts vulst som passar till just den möbeln. Ramarna för hur vulsten skall se ut är nästintill förbestämd då ett slutgiltigt resultat ofta ska återskapas eller restaureras i äldre objekt. I nya möbler finns ingen mall och på så sätt lite mer frihet hur vulsten kan utformas men funktionen är densamma. Vulsten ska hjälpa stoppningen att ge slutgiltig form, karaktär och känsla till möbelns slutgiltiga uttryck. Det som vulsten har gemensamt i båda fallen är att den alltid är dold.

    Genom ett formsökande i det traditionella tapetserarhantverket samt på ett inspirationsbaserat plan har vi tagit fram ett antal prover på olika varianter av vulst. Vulsten har fått möjlighet att förändras och formas med hjälp av olika stygntekniker. Med ett syfte att på ett visuellt och icke funktionsbaserat sätt synliggöra en tapetserares dolda hantverk vill vi påvisa ett annat sätt att förhålla sig till detta specifika moment och det givna hantverket.

  • Björklund, Lowe
    et al.
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    Fogelström, Alma
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    Effektivitet inom sjukvården: En kvalitativ fallstudie om avlastning för sjukhuspersonal inom en sektion vid ett sjukhus i Sverige2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this Bachelor Thesis was to describe if and in what way the connection with the RIA-project within the section at the hospital in Sweden has been effective in relation to the goal that has been established by the section.

    The theoretical framework proceeds from two models that deals with effectiveness which have been adapted to the human resource. The framework treats efficiency and effectiveness with associated subheadings, specifically: Resources, competency, job assignments and goal.

    The study was a qualitative case study with a descriptive nature and a deductive approach. Primary data was collected with accessibility selection with semi-structured interviews with seven respondents. The empirical findings were analysed with a thematic analysis method with themes related to the theoretical framework. The study collected secondary data from books, academic articles and academic journals.

    Empirical data was collected from hospital staff and hospital management within the section at the hospital in Sweden.

    The study reaches the conclusion that the connection with the RIA-project within the section at the hospital in Sweden has been effective in relation to the goal that has been established by the section, but not to what degree it has been effective. The human resources can do more right things, the hospital staff uses its competence to a higher degree and the hospital staff can perform job assignments right in relation to what is associated with their profession. This in turn have led to faster processing and contributed to efficiency which in turn have led to effectiveness in relation to the goal that has been established by the section.

  • Follin, Hector
    et al.
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    Hallenberg, Daniel
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    Utveckling av tjänstefiering genom värdekonstellationer: En studie om hur företag med knappa resurser kan tillhandahålla erbjudanden som främjar relationer och en cirkulär ekonomi2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Information technology, IT, and sustainability work have become strategic questions in almost any business. Not only do firms have to implement IT to optimize current operations, they must transform into new business models which requires high level of competence and strategic thinking which especially small and medium-sized enterprises, SME, tend to lack. Buying refurbished IT-hardware is an option for SME to act sustainable. However, suppliers of those goods seldom offer much more as they too tend to lack the resources needed to provide IT services. IT services are usually critical whether SME will become customers or not since buying IT from one supplier minimizes administration costs as well as it creates deeper relationships. Lack of internal resources has led to SMF outsource parts or whole operations more frequently to external suppliers. But the outsourcing does not come harmless. Leaving an operation to an external supplier requires close relationship with the supplier to maintain quality, making the communication vital. A way for a supplier to facilitate relationships is to develop servitization, i.e go from product- to service-centric offers. To develop servitization regardless the scarce resources suppliers have to co-produce offers. Creating an interactive strategy in networks consisting of actors that co-produce offers creates new value creating systems- value constellations. Suppliers and customers are now part of the value creation as they both participate in the production. Their roles have been broadened and the scarce resources as a barrier has now been eliminated as they now share competences while their relationships are being flourished.

  • Gränström, Danielle
    et al.
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    Atterström, Johanna
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    E-handel av livsmedel: En kvalitativ studie som undersöker hur e-service quality påverkar kundens köpbeteende2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Introduction: E-commerce has shown a large increase in the last years and constitutes a great portion of the market. This has led to a digital shift and more people choose to e-shop. This has affected the retail business, since there are new, more comfortable ways to buy your groceries. Furthermore, the food e-commerce differentiates from the general e-commence, since customers feel comfortable being able to smell, touch and see the groceries they are buying.

    Purpose: The purpose of this study is to achieve a higher and deeper knowledge of how the e-service quality affects the customers purchasing behavior in a digital food commence. Furthermore, the purpose is to identify notable factors within e-service quality which affects the customers purchasing behavior.

    Method: This is a qualitative study which has had an abductive approach. It is a combination between an inductive and a deductive attempt. The empirical material has been collected through six semi-structured interviews with Zeithaml, Parasuraman & Malhotra (2002) e-service quality dimensions for basis. Thereafter the empirical results were analyzed with the different steps of the buying process.

    Conclusion: Through this study, we noticed no significant difference between the interviewees which probably is a result of a high "internet habit". Thanks to the study, we were able to conclude that there are a number of distinct factors within the e-service quality dimensions that affects the customers purchasing behavior. Seeing that this is a subject going through constant development in contemporary with the digital evolution we find it useful to study, because the old barriers are replaced with new ones.

  • de Luca, Vanessa
    et al.
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    Rhan, Jacob
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    Sökmotoranvändares annonsmedvetenhet och attityd mot organiskaoch betalda sökresultat: En kvantitativ studie om hur sökmotoranvändares attityd påverkas av annonsmedvetenhet2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Purpose: The purpose of this study is to examine if there is a relationship between search engine users advertising awareness and attitude towards organic- and/or paid search results.

    Hypothesis: H1: The attitude toward Google´s paid search results is significantly more negative for search engine users who successfully identify more than 75% of Google´s paid search results on the results page compared to search engine users who successfully identified less than 75% of Google´s paid search results on the search results page. H2: The attitude toward Google´s organic search results is significantly more negative for search engine users who successfully identify more than 75% of Google´s paid search results on the search results page compared to search engine users who successfully identified less than 75% of Google´s paid search results on the search results page.

    Methodology: The study is based on the positivist research paradigm and has a quantitative research method and a deductive approach. The research design is a cross- sectional study and a survey has been chosen as a data collection method. The data analysis was completed using the computer program IBM SPSS.

    Results: The results show that there is no relationship between the search engine user´s attitude towards Google´s paid search results and the search engine user´s ad awareness, which means that the null hypothesis 1 cannot be rejected. The results also show that search engine user´s attitude towards Google´s organic search results is significantly more positive for search engine users who identified more than 75% of Google´s paid search results on the search results page as compared to search engine user´s successfully identified less than 75% of Google´s paid search results on the search results page, meaning, the null hypothesis 2 cannot be rejected.

    Contributions: The theoretical contribution is related to persuasion knowledge model (PKM) and shows that (1) search engine user´s activation of persuasion knowledge does not necessarily create a more negative attitude towards paid search results. (2) Search engine user´s activation of persuasion knowledge creates a more positive attitude towards organic search results. The practical contribution is given to Google and is based on the fact that (1) Google can clarify its ad disclosure without the risk of search engine users creating more negative attitude towards paid search results. (2) Google can clarify the ad disclosure, which will lead to more positive attitude towards organic search results for search engine users.

  • Mahmoud Nejad, Sama
    et al.
    Linköping University, Department of Social and Welfare Studies, Learning, Aesthetics, Natural science.
    Ahlberg, Robin
    Linköping University, Department of Social and Welfare Studies.
    Lugna aktiviteter eller bollspel?: En observationsstudie av barns aktivitetsval på fritidshemmet2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Barn spenderar en stor del av sin tid i olika institutioner som skola och fritidshem. I den delen av vardagen som definieras som fritid gör barn olika val av aktiviteter. Begreppet motorik är i detta sammanhang en aspekt av aktiviteter som är intressant att undersöka. Människors rörelseförmåga och rörelsemönster är den generella definitionen på motorik som delas in i finmotorik och grovmotorik. Tidigare forskning visar att pojkar generellt har en mer utvecklad motorik än flickor och att dessa skillnader blir större ju äldre de blir. Syftet med vår uppsats är att undersöka barns val och deltagande i finmotoriska och grovmotoriska aktiviteter på fritidshemmet. Vi har även tittat på hur faktorer som miljö, verksamhet och pedagogers samspel med barnen och deras aktiviteter relaterar till varandra. Studiens resultat grundar sig i observationer på två olika fritidshem i Sverige. Resultatet har granskats med hjälp av våra teoretiska utgångspunkter, genus och sociokulturellt perspektiv. Det som har framkommit i denna studie är att i valet av aktiviteter som är grovmotoriska eller finmotoriska väljer pojkar generellt grovmotoriska aktiviteter och flickor finmotoriska. Sammanfattningsvis i denna studie framgick det att miljö, pedagogers handlingar, barns intressen, förväntningar, föreställningar, normer och olika grader av strukturer i verksamheten utgör faktorer som kan ha betydelse för barns aktivitetsval på fritidshemmet.

  • Lindström, Per
    Linköping University, Department of Computer and Information Science, Database and information techniques.
    Deep Imitation Learning on Spatio-Temporal Data with Multiple Adversarial Agents Applied on Soccer2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Recently, the availability of high quality and high resolution spatio-temporal data has increased for many sports. This enabled deep analysis of player behaviour and game strategy. This thesis investigates the assumption that game strategy is latent information in tracking data from soccer games and the possibility of modelling player behaviour with deep imitation learning. A possible application would be to perform counterfactual analysis, and switch an observed player in a real sequence, with a simulated player to asses alternative scenarios.

    An imitation learning application is implemented using recurrent neural networks. It is shown that the application is able to learn individual player behaviour and perform rollouts on previously unseen sequences.

  • Naronikar, Aditya
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics.
    Riström, Anton
    Luleå University of Technology, Luleå.
    CFD and Experimental Study of Refuelling and Venting a Fuel System2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In 1999, California Air Resources Board (CARB) implemented a regulation that required all gasoline cars sold in California be fitted with an Onboard Refueling Vapor Recovery System (ORVR). The ORVR system is designed to prevent Volatile Organic Compounds (VOCs) from escaping into the atmosphere during refuelling by storing the gas vapours in a carbon canister. Due to the complex nature of the fuel system, making design changes could have large implications on the ORVR performance of the vehicle. It is therefore desirable to develop a CFD model that can predict the effects of design changes, thereby reducing the need to perform physical tests on each design iteration. This master thesis project was performed at the Fuel Systems department at Volvo Cars in order to help reduce project lead times and product development costs by incorporating CFD as a part of the fuel system development cycle. The CFD results obtained were validated through experimental tests that were also performed as part of this project.

    In this master thesis project, a CFD model was developed to simulate the refuelling of gasoline for a California specification Volvo XC90 with an OPW-11B pump pistol. The model was set up in STAR-CCM+ using the Eulerian Volume of Fluid model for multiphase flow, the RANS realizable k-epsilon turbulence model and the two layer all y+ wall treatment. The effects of the carbon canister were modelled as a porous baffle interface in the simulations where viscous and inertial resistances of the porous media were adjusted to obtain a desired pressure drop across the canister. This method proved to be a suitable simplification for this study. The effects of evaporation as well as a chemical adsorption model for the carbon canister have been excluded from the project due to time limitations.

    It was found that the CFD simulations were in good agreement with the experimental results, especially with respect to capturing the overall behaviour of the fuel system during refuelling. It was found that resolving the flow spatially (and temporally) in the filler pipe was a crucial part in ensuring solver stability. A pressure difference between experiment and simulation was also observed as a consequence of excluding evaporation from the CFD model.

    After the CFD model had been verified and validated, changes to different parts of the fuel system were investigated to observe their effects on ORVR performance. These included changing the recirculation line diameter, changing the carbon canister properties and changing the angle of how the pump pistol was inserted into the capless unit. It was found that the recirculation line diameter is a very sensitive design parameter and increasing the diameter would result in fuel vapour leaking back out into the atmosphere. Similarly, increasing the back pressure by swapping to a different carbon canister would result in the leakage of fuel vapour. On the other hand, insignificant changes in system behaviour were observed when the fuel pistol angle was changed.

  • Müller, Carl
    Linköping University, Department of Management and Engineering, Malmstens Linköping University.
    Basning i påse; STEAM BAG: böja trä med hjälp av en ångpåse och framtagning av produkten STEAM BAG2019Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [sv]

    Basning är en metod där värme och fukt används för att göra träplastiskt och böjbart. Den traditionella metoden att böja trä är att använda en låda eller ett rör och påföra värme och ånga för att mjuka upp träet inför böjning. Böjningen sker sedan utanför basningslådan.

    Det här examensarbetet   att basa trä i en påse och genomföra själva böjningen när träet fortfarande finns kvar i ångpåsen. Här beskrivs framtagandet av den flexibla och lättanvända basningspåsen STEAM BAG, från inledande tester, framtagande av böjmall och kompressionsband till utvärdering och jämförelse med traditionell basning.

    Resultatet av mina tester visa att det är möjligt att förbättra böj metoden traditionell basning med hjälp av ångpåsen då det går att bibehålla värmen och ångan under själva böjningsprocessen.

  • Kenell, Ludwig
    et al.
    Linköping University, Department of Management and Engineering, Information Systems. Linköping University, Faculty of Arts and Sciences.
    Berglund, Stigove
    Linköping University, Department of Management and Engineering, Information Systems. Linköping University, Faculty of Arts and Sciences.
    Effektivitet inom distribuerade team: En fallstudie på sociala och tekniska faktorer inom mjukvaruutveckling2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis presents which factors contribute to efficiency in distributed teams working with software development, and how these factors affect the efficiency of the work process. Working effectively in software development projects is a challenge and the distributed factor, that project members are distributed across more than one office, brings additional complexity. Through the study, we want to help make this complexity more manageable. We have carried out a qualitative case study where we have studied a selected distributed project at a software development company. The empirical data has been collected through semi-structured interviews and analyzed based on identified themes. We have mainly identified social factors, but also some technical factors that contribute to an efficient work process. The factors comprise communication, group identity, mood, culture and norms as well as leadership. They include, among other things, implementing well-adapted communication and documentation, holding frequent meetings, few groupings, common IT tools, promoting social communication, having transparent leadership and the team members having a high level of responsibility. In the conclusion we also describe how the listed factors help to achieve an efficient work processes.

  • Walden, Alice
    Linköping University, Department of Management and Engineering, Information Systems. Linköping University, Faculty of Arts and Sciences.
    Decision traceability in agile software projects: Enabling alignment between changing requirements and product goals2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Agile project management emphasizes flexibility and adapting to change. Embracing change often means that specified requirements get changed, removed or replaced under the course of a software project. Another consequence of the nature of agile projects is that everything that does not directly contribute to the working software gets dropped from the product lifecycle. Traceability – the ability to trace requirements back to their origins and forward to design artifacts, code, and testcases – is one such thing that may be overlooked. At the same time, traceability may be crucial to making sure that the delivered product meets the product goals. This thesis investigates the concept of decision traceability – the ability to trace decisions that relate to the evolution of a software product, as well as the fulfillment of product goals. The purpose of this thesis is to understand the importance of decision traceability in relation to product goals and changing requirements in agile software projects. For this purpose, two research questions were developed. (1) What are the challenges of achieving decision traceability in agile projects? And (2) What are important aspects of achieving decision traceability in agile projects? An interpretive qualitative case study was conducted at an IT-consultancy firm. In the case study, two of the organization’s in-house projects were observed, and six informants were interviewed. In answer to the research questions, seven challenges and six important aspects of achieving decision traceability were identified. A conclusion that can be made from the findings is that other aspects than just well-defined processes– such as team engagement, value perception, and communication – may be essential to achieving decision traceability in agile software projects.

  • Hilm, David
    et al.
    Linköping University, Department of Computer and Information Science, Artificial Intelligence and Integrated Computer Systems.
    Rahim, David
    Linköping University, Department of Computer and Information Science, Artificial Intelligence and Integrated Computer Systems.
    Two-factor Authentication and Digital Signing for an Enterprise System utilizing Yubikey2019Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    The use of a second factor to increase the security of systems is growing and has continued to do so for a long time. This thesis explores options for implementation to use a YubiKey as an authentication method (OTP) as well as for signing digital transactions through a web browser client. Measures of network overhead that occurs in conjunction with Digital Signing of transactions are also disclosed. Our findings show that YubiKey provides flexible and readily available solutions that can be used with only small implementations for OTP authentication. It is also shown that the major concern for implementing a solution for a web browser is to intuitively use certificates stored on a USB-device without installing any plugins or with the use of a third-party application running on the client machine.

  • Smyth, Jonas
    et al.
    Linköping University, Department of Management and Engineering, Information Systems. Linköping University, Faculty of Arts and Sciences.
    Johansson, Simon
    Linköping University, Department of Management and Engineering, Information Systems. Linköping University, Faculty of Arts and Sciences.
    Mikroföretagens strategiska vägval för att tävla på en konkurrensutsatt ITmarknad: En fallstudie om mikroföretagens utmaningar och möjligheter2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The IT market is influenced with constant changes and a highly competitive environment between many different entities. In entrepreneurship, it is often the strategy that determines whether an organization successfully can establish itself and compete within a business area. It is a major challenge to successfully compete as a micro enterprise due to limited supply of resources. The aim of the study was thus to examine how micro enterprises handle strategic choices in order to gain competitive advantage on the IT market, as well as investigate the challenges and opportunities for a micro enterprise in their quest for competitiveness. The study was conducted through a qualitative interpretive case study. Semi-structured interviews were used to collect data from six respondents with different perspectives on entrepreneurship within micro enterprises. The six respondents represent four different micro enterprises and an incubator that offers strategic guidance for newly started IT companies. The result of the study presents that it is fairly easy to start competing within the IT market. It takes few resources to develop a concept and spread it to a wide range of potential customers. As a micro enterprise, the IT market is thus lucrative as it is easy and quick to penetrate. However, the market exists of constant threats from other newcomers. Small companies need a continual inflow of financial resources in order to be able to progress the business, which leads to high demands on the ability to quickly establish itself on the market. Large organizations can hardly be an efficient customer for micro enterprises because of their immobility. Strategy is generally handled scarcely within micro enterprises. The IT markets uncertainty and the constant changes makes it hard for micro enterprises to formalize pronounced strategies in the long term. It does however exist a strategic way of thinking within micro enterprises, although on an informal and improvisational level. On the other hand, strategies for both differentiation and segmentation are sought, sometimes in combination with each other. Micro enterprises in the IT market is driven by entrepreneurship and innovation, which results in the development of differentiated products and services. In a constantly changing market, micro enterprises have great opportunities to achieve flexibility and rapid mobility in a different manner compared to larger companies. Hence, micro enterprises can quickly react and adapt to the ever-changing world of IT.

  • Brandt, Daniel
    et al.
    Linköping University, Department of Computer and Information Science.
    Fasth, Frida
    Linköping University, Department of Computer and Information Science.
    Gustavsson, Adam
    Linköping University, Department of Computer and Information Science.
    Janfalk, Elsa
    Linköping University, Department of Computer and Information Science.
    Kimiaei, Felix
    Linköping University, Department of Computer and Information Science.
    Lindholm, Victor
    Linköping University, Department of Computer and Information Science.
    Palmlund, Victor
    Linköping University, Department of Computer and Information Science.
    Swensson, Styrbjörn
    Linköping University, Department of Computer and Information Science.
    En undersökning av on-site-faktorers påverkan på en e-handelsplattform2019Independent thesis Basic level (degree of Bachelor), 12 credits / 18 HE creditsStudent thesis
    Abstract [en]

    As a result of trends identified in the report and marketing plan, the importance of a search engine optimized platform for e-commerce is established. In order to further examine the implementation of such, a website was constructed with this purpose in mind. The of said website was designed based on user stories which in their turn partly came from competitor's websites and partly from preference. In order to optimize the website for search engines, four established factors were optimized to the best of the group's ability. These factors were responsivity, custom 404-page, sitemap and keywords. Testing these factors against Google, the tests were ran partly through the search engine itself and partly through the third-party programmes WebSite Auditor and SERPROBOT. In accordance with expectations, the keywords had a considerable effect on the acquired results, but the remaining factors had nothing more than a marginal contribution; this was not expected. The experiment had many sources of error and and low reliability, cheifly on account of the chosen instruments for measure and a statistical uncertainty as a result of few observations. The conclusion made is that keywords have a greater effect than the other evaluated factors.

  • Bouilloux-Lafont, Antoine
    et al.
    Linköping University, Department of Management and Engineering, Machine Design.
    Noya Pozo, Rubén
    Development of Acoustic Simulations using Parametric CAD Models in COMSOL2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    With constantly changing regulations on emissions, heavy commercial vehicles manufacturershave to adapt for their products to preserve their quality while meetingthese new requirements. Over the past decades, noise emissions have become a greatconcern and new stricter laws demand companies to decrease their vehicle pass-bynoise target values.To address the requirements from different disciplines, Scania follows a simulationdriven design process to develop new concept models EATS. The collaboration amongengineers from different fields is thereby necessary in order to obtain higher performancesilencers. However, the pre-processing step in terms of acoustic simulationsis time-consuming, which can slow the concept development process.In this thesis, a new method was introduced to automate the pre-processing of silenceracoustic models and allow for design optimisation based on acoustic performanceresults. A common Scania product study case was provided to several theseswithin the NXD organisation. The collaboration among the master thesis workersaimed to demonstrate the benefits of KBE and MDO and how they can be integratedwithin Scania’s current concept development and product introduction processes.The performed work was divided in the following steps: data collection, methoddevelopment and concluding work. The first step consisted in gathering sufficientknowledge by conducting a thorough literature review and interviews. Then, an initialmethod was formulated and tested on a simplified silencer model. Once approvedand verified, the method was applied to the study case EATS.The study case showed that a complex product can have its acoustic pre-processingstep automated by ensuring a good connectivity among the required software anda correct denomination of the geometrical objects involved in the simulations. Themethod investigated how morphological optimisations can be performed at bothglobal and local levels to enhance the transmission loss of a silencer. Besides optimisingthe acoustic performance of the models, the method allowed the identificationof correlations and inter-dependencies among their design variables and ouput parameters.

  • Eriksson, Hanna
    Linköping University, Department of Management and Engineering, Machine Design.
    On-Board Data Aquisition System: Conceptual Design of an Airdrop Tracking System2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis is, on behalf of Saab AB, a pre-study of possible on-board solutions for position measuring during store separation tests aimed for the test and evaluation of JAS 39 Gripen. The purpose is to replace the present ground-based system in order to achieve more effective trials regarding time and economy.

    Three different concept development methodologies were investigated in order to find the most suitable one for this thesis. Those were merged into one adapted methodology containing the following phases; \textit{Planning}, \textit{Function Analysis}, \textit{Concept Generation} and \textit{Concept Evaluation}.

    The work progressed as the methodology states, and the highest amount of work was dedicated to the Planning phase. The requirements and desiderata for the system were produced with an agile process, resulting in the Construction Specification List that eventually became the basis for the Concept Generation phase.

    Knowledge about the technical theory needed to solve the problem was obtained in parallel with the Function Analysis and Concept Generation. The most adaptable techniques to measure position were found out to be with the use of the Global Positioning System (GPS) or Inertial Navigation System (INS).

    After an extensive work with the Concept Generation in parallel with a continuously updated Construction Specification List, three concepts were developed. One concept is based on GPS, the second one on INS and the third one is a combination of GPS and INS. All three concepts shares the same telemetry system and casing, which fulfills the requirement of simple installation and possibility to install in different stores.

    In the final phase, Concept Evaluation, a comparison between the concepts was performed. Advantages and disadvantages was listed and the fulfillment of requirements was investigated. All three concepts were handed over to Saab in order to let them decide which concept(s) to further develop.

  • Palmé, Anna
    et al.
    Fitzgerald, Heli
    Botany, Finnish Museum of Natural History, University of Helsinki, Finland.
    Weibull, Jens
    Swedish University of Agricultural Sciences.
    Bjureke, Kristina
    Natural History Museum, Norway.
    Eisto, Kaija
    Endresen, Dag
    Geo-Ecology Research Group, Natural History Museum, Oslo, Norway.
    Hagenblad, Jenny
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Hyvärinen, Marko
    Botany, University of Helsinki, Finland.
    Kiviharju, Elina
    Natural Resources Institute Finland (Luke), Helsinki, Finland.
    Lund, Birgitte
    Rasmussen, Morten
    Þorbjörnsson, Hjörtur
    Reykjavík Botanic Garden, Reykjavik, Iceland.
    Nordic Crop Wild Relative conservation: A report from two collaborative projects 2015–20192019Report (Other academic)
    Abstract [en]

    The report summarizes results from a cooperation among all the Nordic countries during the period 2015 – 2019 (two projects). The work has focused on the conservation of Crop Wild Relatives (CWR), i.e. wild plant species closely related to crops. They are of special importance to humanity since traits of potential value for food security and climate change adaptation can be transferred from CWR into crops. The projects represent the first joint action on the Nordic level regarding in situ conservation of CWR. Substantial progress has been made regarding CWR conservation planning, including development of a Nordic CWR checklist and identification of suitable sites for CWR conservation. A set of recommended future actions was developed, with the most important one being initiation of active in situ conservation of CWR in all Nordic countries.

  • Public defence: 2019-09-13 13:15 Ada Lovelace, B-huset, Linköping
    Ghasemi Zinatabadi, Fatemeh
    Linköping University, Department of Mathematics, Computational Mathematics. Linköping University, Faculty of Science & Engineering.
    Stability, dual consistency and conservation of summation-by-parts formulations for multiphysics problems2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis, we consider the numerical solution of initial boundary value problems (IBVPs). Boundary and interface conditions are derived such that the IBVP under consideration is well-posed. We also study the dual problem and the related dual boundary/interface conditions. Once the continuous problem is analyzed, we use finite difference operators with the Summation- By-Parts property (SBP) and a weak boundary/interface treatment using the Simultaneous-Approximation-Terms (SAT) technique to construct high-order accurate numerical schemes. We focus in particular on stability, conservation and dual consistency. The energy method is used as our main analysis tool for both the continuous and numerical problems.

    The contributions of this thesis can be divided into two parts. The first part focuses on the coupling of different IBVPs. Interface conditions are derived such that the continuous problem satisfy an energy estimate and such that the discrete problem is stable. In the first paper, two hyperbolic systems of different size posed on two domains are considered. We derive the dual problem and dual interface conditions. It is also shown that a specific choice of penalty matrices leads to dual consistency. As an application, we study the coupling of the Euler and wave equations. In the fourth paper, we examine how to couple the compressible and incompressible Navier-Stokes equations. In order to obtain a sufficient number of interface conditions, the decoupled heat equation is added to the incompressible equations. The interface conditions include mass and momentum balance and two variants of heat transfer. The typical application in this case is the atmosphere-ocean coupling.

    The second part of the thesis focuses on the relation between the primal and dual problem and the relation between dual consistency and conservation. In the second and third paper, we show that dual consistency and conservation are equivalent concepts for linear hyperbolic conservation laws. We also show that these concepts are equivalent for symmetric or symmetrizable parabolic problems in the fifth contribution. The relation between the primal and dual boundary conditions for linear hyperbolic systems of equations is investigated in the sixth and last paper. It is shown that for given well-posed primal/dual boundary conditions, the corresponding well-posed dual/primal boundary conditions can be obtained by a simple scaling operation. It is also shown how one can proceed directly from the well-posed weak primal problem to the well-posed weak dual problem.  

    List of papers
    1. Coupling Requirements for Multiphysics Problems Posed on Two Domains
    Open this publication in new window or tab >>Coupling Requirements for Multiphysics Problems Posed on Two Domains
    2017 (English)In: SIAM Journal on Numerical Analysis, ISSN 0036-1429, E-ISSN 1095-7170, Vol. 55, no 6, p. 2885-2904Article in journal (Refereed) Published
    Abstract [en]

    We consider two hyperbolic systems in first order form of different size posed on two domains. Our ambition is to derive general conditions for when the two systems can and cannot be coupled. The adjoint equations are derived and well-posedness of the primal and dual problems is discussed. By applying the energy method, interface conditions for the primal and dual problems are derived such that the continuous problems are well posed. The equations are discretized using a high order finite difference method in summation-by-parts form and the interface conditions are imposed weakly in a stable way, using penalty formulations. It is shown that one specic choice of penalty matrices leads to a dual consistent scheme. By considering an example, it is shown that the correct physical coupling conditions are contained in the set of well posed coupling conditions. It is also shown that dual consistency leads to superconverging functionals and reduced stiffness.

    Place, publisher, year, edition, pages
    Society for Industrial and Applied Mathematics, 2017
    Keywords
    well posed problems, high order finite diffrences, stability, summation-by-parts, weak interface conditions, dual consistency, stiffness, superconvergence
    National Category
    Computational Mathematics
    Identifiers
    urn:nbn:se:liu:diva-143261 (URN)10.1137/16M1087710 (DOI)000418663500015 ()
    Available from: 2017-11-28 Created: 2017-11-28 Last updated: 2019-08-01Bibliographically approved
    2. On the relation between conservation and dual consistency for summation-by-parts schemes
    Open this publication in new window or tab >>On the relation between conservation and dual consistency for summation-by-parts schemes
    2017 (English)In: Journal of Computational Physics, ISSN 0021-9991, E-ISSN 1090-2716, Vol. 344, p. 3p. 437-439Article in journal (Refereed) Published
    Abstract [en]

    n/a

    Publisher
    p. 3
    Keywords
    Initial boundary value problems Summation-by-parts Conservation, Dual consistent, Multi-block, Multi-element
    National Category
    Mathematics
    Identifiers
    urn:nbn:se:liu:diva-137545 (URN)10.1016/j.jcp.2017.04.072 (DOI)000402481300021 ()
    Note

    Classified in the journal as "Short note"

    Available from: 2017-05-21 Created: 2017-05-21 Last updated: 2019-08-01
    3. Corrigendum to “On the relation between conservation and dual consistency for summation-by-parts schemes”[J. Comput. Phys. 344 (2017) 437–439]
    Open this publication in new window or tab >>Corrigendum to “On the relation between conservation and dual consistency for summation-by-parts schemes”[J. Comput. Phys. 344 (2017) 437–439]
    2018 (English)In: Journal of Computational Physics, ISSN 0021-9991, E-ISSN 1090-2716, Vol. 360, p. 247-247Article in journal (Refereed) Published
    Place, publisher, year, edition, pages
    Academic Press, 2018
    National Category
    Mathematics
    Identifiers
    urn:nbn:se:liu:diva-145718 (URN)10.1016/j.jcp.2018.02.046 (DOI)000428966300014 ()
    Available from: 2018-03-19 Created: 2018-03-19 Last updated: 2019-08-01Bibliographically approved
    4. An energy stable coupling procedure for the compressible and incompressible Navier-Stokes equations
    Open this publication in new window or tab >>An energy stable coupling procedure for the compressible and incompressible Navier-Stokes equations
    2019 (English)In: Journal of Computational Physics, ISSN 0021-9991, E-ISSN 1090-2716, Vol. 396, p. 280-302Article in journal (Refereed) Epub ahead of print
    Abstract [en]

    The coupling of the compressible and incompressible Navier-Stokes equations is considered. Our ambition is to take a first step towards a provably well posed and stable coupling procedure. We study a simplified setting with a stationary planar interface and small disturbances from a steady background flow with zero velocity normal to the interface. The simplified setting motivates the use of the linearized equations, and we derive interface conditions such that the continuous problem satisfy an energy estimate. The interface conditions can be imposed both strongly and weakly. It is shown that the weak and strong interface imposition produce similar continuous energy estimates. We discretize the problem in time and space by employing finite difference operators that satisfy a summation-by-parts rule. The interface and initial conditions are imposed weakly using a penalty formulation. It is shown that the results obtained for the weak interface conditions in the continuous case, lead directly to stability of the fully discrete problem.

    Keywords
    Compressible fluid, Incompressible fluid, Navier-Stokes equations, Energy estimate, Interface conditions, Stability
    National Category
    Mathematics
    Identifiers
    urn:nbn:se:liu:diva-159116 (URN)10.1016/j.jcp.2019.07.022 (DOI)
    Available from: 2019-07-29 Created: 2019-07-29 Last updated: 2019-08-01
    5. On conservation and dual consistency for summation-by-parts based approximations of parabolic problems
    Open this publication in new window or tab >>On conservation and dual consistency for summation-by-parts based approximations of parabolic problems
    2019 (English)Report (Other academic)
    Abstract [en]

    We consider the coupling of parabolic problems discretized using difference operators on summation-by-parts (SBP) form with interface conditions imposed weakly. In, it was shown that conservation and dual consistency are equivalent concepts for linear conservation laws. Here, we show that these concepts are equivalent also for symmetric or symmetrizable parabolic problems, exemplified by the heat equation. We rewrite the heat equation as first order system as in the local discontinuous Galerkin method and show the equivalence of dual consistency and conservation for both the first and second order forms.

    Place, publisher, year, edition, pages
    Linköping: Linköping University Electronic Press, 2019. p. 9
    Series
    LiTH-MAT-R, ISSN 0348-2960 ; 2019:5
    National Category
    Computational Mathematics Mathematics
    Identifiers
    urn:nbn:se:liu:diva-158903 (URN)LiTH-MAT-R--2019/05--SE (ISRN)
    Available from: 2019-07-17 Created: 2019-07-17 Last updated: 2019-08-12Bibliographically approved
    6. The Relation Between Primal and Dual Boundary Conditions for Hyperbolic Systems of Equations
    Open this publication in new window or tab >>The Relation Between Primal and Dual Boundary Conditions for Hyperbolic Systems of Equations
    2019 (English)Report (Other academic)
    Abstract [en]

    In this paper we study boundary conditions for linear hyperbolic systems of equations and the corresponding dual problems. In particular, we show that the primal and dual boundary conditions are related by a simple scaling relation. It is also shown that the weak dual problem can be derived directly from the weak primal problem.

    Based on the continuous analysis, we discretize and perform computations with a high-order finite difference scheme on summation-by-parts form with weak boundary conditions. It is shown that the results obtained in the continuous analysis lead directly to stability results for the primal and dual discrete problems. Numerical experiments corroborate the theoretical results.

    Place, publisher, year, edition, pages
    Linköping: Linköping University Electronic Press, 2019. p. 22
    Series
    LiTH-MAT-R, ISSN 0348-2960 ; 2019:6
    Keywords
    Hyperbolic systems, boundary conditions, primal problem, dual problem, well-posedness, dual consistency
    National Category
    Computational Mathematics Mathematics
    Identifiers
    urn:nbn:se:liu:diva-158904 (URN)LiTH-MAT-R--2019/06--SE (ISRN)
    Available from: 2019-07-17 Created: 2019-07-17 Last updated: 2019-08-12Bibliographically approved
  • Public defence: 2019-09-13 10:15 Planck, Fysikhuset, Linköping
    Engberg, David L. J.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Atom Probe Tomography of Hard Nitride and Boride Thin Films2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Hard ceramic thin films, including TiSiN, ZrAlN, ZrB2, and ZrTaB2, with applications for wear-resistant coatings, have been studied using atom probe tomography and correlated with several other analytical techniques, including X-ray diffraction, electron microscopy, and elastic recoil detection analysis. Outstanding obstacles for quantitative atom probe tomography of ceramic thin films have been surmounted.

    Mass spectral overlaps in TiSiN, which make 28Si indistinguishable from 14N, was resolved by isotopic substitution with 15N, and the nanostructural distribution of elements was thus revealed in 3-D, which enabled the identification of additional structural elements within the nanostructured Ti0.81Si0.1915N film. Improvements to the growth model of TiSiN by cathodic arc deposition was suggested.

    A self-organized nanolabyrinthine structure of ZrAlN, consisting of standing lamellae of fcc-ZrN and hexagonal AlN, was investigated with focus on the onset and limits of the self-organization. The local crystallographic orientational relationships were (001)ZrN || (0001)AlN and <110>ZrN || <2-1-10>AlN. Close to the MgO substrates, a smooth transition region was formed, going from segregated and disordered to the self-organized nanolabyrinthine structure. With increased growth temperature, coarse (111)-oriented ZrN grains occasionally precipitated and locally replaced the nanolabyrinthine structure. Significant local magnification effects rendered the Zr and N signals unusable, thereby inhibiting quantitative compositional analysis of the constituent phases, but the nanostructure was resolved using the Al signal.

    Ceramic materials are often affected by correlated evaporation, which can result in losses due to the detector dead-time/space. A compositional correction procedure was suggested, tested against an established procedure, and applied to ZrB2. The correction was found to be less dependent on the isotope abundances and background correction compared to the established procedure. While losses due to dead-time/space occur in atom probe tomography of all materials, the correlative field evaporation behavior of ceramics significantly increases the compositional error. The evaporation behavior of ZrB2 was therefore thoroughly investigated and evidence of preferential retention, correlated evaporation, and inhomogeneous field distributions at a low-index pole was presented. The high mass resolution, relatively low multiple events percentage, and quality of the co-evaporation correlation data was partly attributed to the crystal structure and film orientation, which promoted a layer-by-layer field evaporation.

    The evaporation behavior of the related ZrTaB2 films was found to be similar to that of ZrB2. The distribution of Ta in relation to Zr was investigated, showing that the column boundaries were both metal- and Ta-rich, and that there was a significant amount of Ta in solid solution within the columns.

    In addition, an instrumental artefact previously not described in atom probe tomography was found in several of the materials investigated in this thesis. The artefact consists of high-density lines along the analysis direction, which cannot be related to pole artefacts. The detection system of the atom probe was identified as the cause, because the artefact patterns on detector histograms coincided with the structure of the microchannel plate. Inconsistencies in the internal boundaries of the microchannel plate multifibers from the manufacturing process can influence the signal to the detector and locally increase the detection efficiency in a pattern characteristic to the microchannel plate in question.

    Altogether, this thesis shows that atom probe tomography of nitride and boride thin films is burdened by several artefacts and distortions, but that relevant material outcomes can nevertheless be achieved by informed choices of film isotopic constituents and analytical parameters, exclusion of heavily distorted regions (such as pole artefacts), and the use of compositional correction procedures when applicable.

    List of papers
    1. Resolving Mass Spectral Overlaps in Atom Probe Tomography by Isotopic Substitutions: Case of TiSi15N
    Open this publication in new window or tab >>Resolving Mass Spectral Overlaps in Atom Probe Tomography by Isotopic Substitutions: Case of TiSi15N
    Show others...
    2018 (English)In: Ultramicroscopy, ISSN 0304-3991, E-ISSN 1879-2723, Vol. 184, p. 51-60Article in journal (Refereed) Published
    Abstract [en]

    Mass spectral overlaps in atom probe tomography (APT) analyses of complex compounds typically limit the identification of elements and microstructural analysis of a material. This study concerns the TiSiN system, chosen because of severe mass-to-charge-state ratio overlaps of the 14N+ and 28Si2+ peaks as well as the 14N and 28Si2+ peaks. By substituting 14N with 15N, mass spectrum peaks generated by ions composed of one or more N atoms will be shifted toward higher mass-to-charge-state ratios, thereby enabling the separation of N from the predominant Si isotope. We thus resolve thermodynamically driven Si segregation on the nanometer scale in cubic phase Ti1-xSix15N thin films for Si contents 0.08 ≤ x ≤ 0.19 by APT, as corroborated by transmission electron microscopy. The APT analysis yields a composition determination that is in good agreement with energy dispersive X-ray spectroscopy and elastic recoil detection analyses. Additionally, a method for determining good voxel sizes for visualizing small-scale fluctuations is presented and demonstrated for the TiSiN system.

    Place, publisher, year, edition, pages
    Elsevier, 2018
    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:liu:diva-122721 (URN)10.1016/j.ultramic.2017.08.004 (DOI)000415650200007 ()28850866 (PubMedID)
    Note

    Funding Agencies:VINN Excellence Center on Functional Nanoscale Materials (FunMat) [2007-00863]; Swedish Research Council (VR) project [2013-4018]; Swedish Government Strategic Research Area Grant in Materials Science (Grant SFO Mat-LiU) on Advanced Functional Materials [2009-00971]; Knut and Alice Wallenberg Project Isotope

    Available from: 2015-11-18 Created: 2015-11-18 Last updated: 2019-08-01Bibliographically approved
    2. Self-organized Nanostructuring in Zr0.64Al0.36N Thin Films Studied by Atom Probe Tomography
    Open this publication in new window or tab >>Self-organized Nanostructuring in Zr0.64Al0.36N Thin Films Studied by Atom Probe Tomography
    Show others...
    2016 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, p. 233-238Article in journal (Refereed) Published
    Abstract [en]

    We have applied atom probe tomography (apt) to analyze the selforganized structure of wear-resistant Zr0.64Al0.36N thin films grown by magnetron sputtering. Transmission electron microscopy shows that these films grow as a two-dimensional nanocomposite, consisting of interleaved lamellae in a labyrinthine structure, with a size scale of ∼ 5 nm. The structure was recovered in the Al apt signal, while the Zr and N data lacked structural information due to severe local magnification effects. The onset of the self-organized growth was observed to occur locally by nucleation, at 5-8 nm from the MgO substrate, after increasing Zr-Al compositional fluctuations. Finally, it was observed that the self-organized growth mode could be perturbed by renucleation of ZrN.

    Place, publisher, year, edition, pages
    Elsevier, 2016
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-84258 (URN)10.1016/j.tsf.2016.07.034 (DOI)000381939700037 ()
    Note

    Funding agencies: VINN Excellence Center on Functional Nanoscale Materials; Swedish Research Council; Swedish Government Strategic Faculty Grant in Materials Science (SFO Mat-LiU) at Linkoping University; Swedish Governmental Agency for Innovation Systems (Vinnova) [2011-0

    Vid tiden för disputationen förelåg publikationen som manuskript

    Available from: 2012-10-03 Created: 2012-10-03 Last updated: 2019-08-02Bibliographically approved
    3. Strategy for simultaneously increasing both hardness and toughness in ZrB2-rich Zr1-xTaxBy thin films
    Open this publication in new window or tab >>Strategy for simultaneously increasing both hardness and toughness in ZrB2-rich Zr1-xTaxBy thin films
    Show others...
    2019 (English)In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 37, no 3, article id 031506Article in journal (Refereed) Published
    Abstract [en]

    Refractory transition-metal diborides exhibit inherent hardness. However, this is not always sufficient to prevent failure in applications involving high mechanical and thermal stress, since hardness is typically accompanied by brittleness leading to crack formation and propagation. Toughness, the combination of hardness and ductility, is required to avoid brittle fracture. Here, the authors demonstrate a strategy for simultaneously enhancing both hardness and ductility of ZrB2-rich thin films grown in pure Ar on Al2O3(0001) and Si(001) substrates at 475 degrees C. ZrB2.4 layers are deposited by dc magnetron sputtering (DCMS) from a ZrB2 target, while Zr1-xTaxBy alloy films are grown, thus varying the B/metal ratio as a function of x, by adding pulsed high-power impulse magnetron sputtering (HiPIMS) from a Ta target to deposit Zr1-xTaxBy alloy films using hybrid Ta-HiPIMS/ZrB2-DCMS sputtering with a substrate bias synchronized to the metal-rich portion of each HiPIMS pulse. The average power P-Ta (and pulse frequency) applied to the HiPIMS Ta target is varied from 0 to 1800W (0 to 300 Hz) in increments of 600W (100 Hz). The resulting boron-to-metal ratio, y = B/(Zr+Ta), in as-deposited Zr1-xTaxBy films decreases from 2.4 to 1.5 as P-Ta is increased from 0 to 1800W, while x increases from 0 to 0.3. A combination of x-ray diffraction (XRD), glancing-angle XRD, transmission electron microscopy (TEM), analytical Z-contrast scanning TEM, electron energy-loss spectroscopy, energy-dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy, and atom-probe tomography reveals that all films have the hexagonal AlB2 crystal structure with a columnar nanostructure, in which the column boundaries of layers with 0 amp;lt;= x amp;lt; 0.2 are B-rich, whereas those with x amp;gt;= 0.2 are Ta-rich. The nanostructural transition, combined with changes in average column widths, results in an similar to 20% increase in hardness, from 35 to 42 GPa, with a simultaneous increase of similar to 30% in nanoindentation toughness, from 4.0 to 5.2MPa root m. Published by the AVS.

    Place, publisher, year, edition, pages
    A V S AMER INST PHYSICS, 2019
    National Category
    Inorganic Chemistry
    Identifiers
    urn:nbn:se:liu:diva-159001 (URN)10.1116/1.5093170 (DOI)000472182400035 ()
    Note

    Funding Agencies|Swedish Research Council VR [2014-5790, 2018-03957, 642-2013-8020]; Knut and Alice Wallenbergs foundation [KAW 2015.0043]; VINNOVA [2018-04290]; Aforsk Foundation [16-359]; Carl Tryggers Stiftelse [CTS 15: 219, CTS 17: 166, CTS 14: 431]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO Mat LiU) [2009 00971]

    Available from: 2019-07-19 Created: 2019-07-19 Last updated: 2019-08-01
  • Alander, Johanna
    et al.
    Linköping University, Department of Management and Engineering, Environmental Technology and Management.
    Nylin, Adam
    Linköping University, Department of Management and Engineering, Environmental Technology and Management.
    Feasibility study for producing and using biogas in Chisinau, Moldova2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    More and more people live in cities, cities that both present opportunities, in terms of potential sustainable growth and challenges, for example regarding insufficient infrastructure and waste management. There are several examples on initiatives to make cities reach their sustainability potential; one is to turn municipal organic waste, MOW, and sewage sludge into biogas and use it to produce electricity and/or heat or to upgrade it to biomethane and use it as a fuel in for example public transport or feed it to a gas grid.

    This study has focused on the potential and feasibility of producing and using biogas/biomethane as well as the remains from the production process, called digestate, in Chisinau, the capital of Moldova. For the most feasible options an indication of the environmental improvement and economic performance was also estimated. The study included biogas produced from municipal organic waste, sewage sludge and methane collected at landfills. For the areas of use, electricity or heat produced from biogas was included as well as using biomethane in public transport or feeding it to the gas grid and to use the digestate as biofertilizer. Since multiple factors needs to be considered in order to adequately assess the potential and feasibility a multi-criteria approach was used for developing a framework based on an early assessment tool for biomethane solutions in the urban context.

    In summary it is indicated that there are good conditions for biogas production in Chisinau with biogas production from sewage sludge being included in the ongoing rehabilitation of the largest wastewater facility and methane collection from the largest landfill historically being part of the operations and planned (although not confirmed) to soon be part of these again. However, the largest potential is for municipal organic waste where the main impediments relates to financial issues and to some extent legislation that indirectly favour short term landfilling. When investigating the possible use of the digestate as biofertilizer the outlooks are considerably less promising than for the supply side. Despite the fact that the law explicitly allows the use of digestate (both from MOW and sewage sludge) the lack of knowledge within the farmer community result in a low or non-existent customer demand. Regarding the possible use of biogas/biomethane it was concluded that electricity production is the most feasible option and heat generation placing as the second most feasible. Feeding the gas to the grid appears more difficult and the least likely option is for the biogas to be used within public transport. Overall it is in general technically possible to use the gas in terms of infrastructure and there is some demand, especially for electricity and heat. The biggest inhibitory factors are rather institutional since biogas in general is overlooked or not prioritized in the strategies leading to a shortcoming in economical instruments or funds and to some extent in the legislation.

    This thesis is complemented by an executive summary with the same name, both in English and translated to Romanian.

  • Brandt, Juliana
    Linköping University, Department of Management and Engineering, Project Innovations and Entrepreneurship.
    Förändringsarbete av informationsflöden i en interorganisatorisk samverkan2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In recent years, the train's punctuality, Sweden's ranking in the European Railway Performance Index and the train industry's customer satisfaction have decreased. The largest and most influential players in the train industry are Trafikverket and SJ AB, which are two state-owned organizations. The low customer satisfaction in the train industry is based on SJ AB’s failure to deliver the latest traffic information in case of delay. Since Trafikverket manages the majority of the railway network and SJ AB is Sweden's largest train operator, there is a high degree of mutual dependence between them in order for each organization to be able to conduct its business. At present, there is a clear division of responsibility between these actors regarding how and where the traffic information is distributed. Where the Trafikverket is responsible for conveying all information on its website and on the signs while SJ AB is responsible for conveying information on its website and in its application, as well as via textmessage and mail communication. The processes for communication between the actors regarding delays, track changes and other changes in the journey are done manually with digital tools as support. Today, several uncertainties are experienced in these processes, based on the fact that traffic control at SJ AB currently does not receive any confirmation from Trafikverket if any changes have been made. Due to these factors, this study will investigate the flow of information between SJ traffic control and the Trafikverket’s train services.

    Therefore, the purpose of this thesis was to identify existing communications, more specifically information flows of traffic data, between the organizations and their passengers, along with identifying possible improvements in the information flows through digitization. The thesis also explores the change opportunities for a department with many manual processes.

    The study was conducted with a multi-method structure consisting of a literature study, observation study, questionnaire study, interview study and benchmarking. During the observation, questionnaire and interview study, the focus was on employees at SJ traffic control and other relevant departments at SJ AB and the benchmarking was conducted through external interviews. This led to the identification of the main reasons of mismanagement of traffic information and best practices. This was later analyzed with the help of collected theory, which then led to discussion, conclusion and recommendations to SJ AB.

    It’s obvious that traffic information has low status within SJ AB as well as the interorganizational alliance. This has hampered the development of internal processes related to managing traffic information and therefore the processes lack standardized procedures and structured routines. The main reasons of mismanagement of traffic information depend on the human factor and specific individuals. This is based on the fact that it was clear that both traffic controls perceived the received traffic information difficult to interpret and unstructured, this depending on who sent the information. This due to the fact that the individuals use varying expressions and internal technical language. To be able to improve and in the future automate the information flows between the actors a standardized working procedure with associated technical language is required in the industry. To establish a technical language, the status of the traffic information must be increased within the organizations and a dictionary for which expressions should be used, where all used expressions are listed and defined. Additionally, a clearer goal of the alliance is required.

  • Björk, Andreas
    et al.
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics.
    Enander, Tobias
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics.
    Validering och utveckling av matematisk modell av rökgaskondensering: En undersökning av matematiska modeller avrökgaskondensering samt en studie av hur yttre faktorerpåverkar rökgaskondenseringen i kraftvärmeverk2019Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    When burning fuels with high water or hydrogen content, much of the combustion energy follows themoist air that leaves the chimney at the plant. A common example is the combustion of wood fuel orhousehold waste in CHP-plants. In order to increase the plant's efficiency and at the same time clean theair from sulfur dioxide and metals, a flue gas condensation of scrubber-type can be used. Cool water isinjected into a filling bed and meets the hot flue gas. When the flue gases are cooled, energy is released bythe water in the flue gases when vapor turns into liquid form, energy that can be used e.g. to heat thedistrict heating network's return line.

    This work has been carried out on behalf of Hifab DU-teknik, which in the past year has carried outstudies and calculations of the flue gas condensation at the Torsvik CHP plant, which has led to improvedefficiency. Through simulations and calculations in Matlab, this report tries to verify the optimalcondensate flow calculated by DU technology and study how the plant is affected by changed flows andtemperatures in the district heating network’s return line.

    The authors of this work have put a lot of effort into understanding the theory of heat exchangers andenergy in moist air in depth. The theoretical framework we set up can be seen as a thorough introductionto the subjects and an in-depth study compared to the usual course content during the Bachelor's degreeprogram in mechanical engineering at Linköping University.

    The goal of the preparatory method work has been to find expressions of the different temperatures inthe plant that make it possible to simulate changes in the plant. Models have been developed to be able tosimulate and calculate the outgoing temperatures given different mass flows using the ingoingtemperatures in a heat exchanger. The model has proven to work well for the heat exchanger, which isconnected to the district heating network. In the calculations of temperatures out of the filling bed, twomethods have been tested. The authors’ has studied what happens if the condensate temperature out ofthe filling bed is set to the dew temperature of the flue gases. Attempts have also been made to considerthe filling bed as a kind of heat exchanger.

    The result of the authors' calculations of condensate flow differs to a certain extent from the DU-teknik’scalculated condensate flows during a changed boiler load in the plant. To end up at the same result, thehot condensate temperature needed to take a slightly higher temperature than the dew temperature. Theassumption is reasonable to make, but it is difficult to draw any conclusions about the magnitude.

    Regarding the method of considering the filling bed as a heat exchanger, there are both successes andshortcomings. The success lies in that the trend for the different temperatures seems to be in line with thetheory that the authors have presented for heat exchangers and what happens when the massflowsincrease or decrease in a heat exchanger. However, the shortcomings lie in the fact that the method doesnot take into account that heat is released during the condensation, but is based entirely on the fact thatthe fluid in the filling bed do not undergo phase transformations.

    Two important proposals for continued work are highlighted at the end of the report. It would beinteresting to study the possibility of considering the filling bed as two separate heat exchangers, where thedry flue gases encounter a partial current of the condensate and the moisture in the flue gases meetsanother partial current of the condensate. Furthermore, a desire is made to test the flue gas condensationin the future at different condensate flows for a longer period of time in order to achieve stationaryconditions in the temperatures. The data can later be used to produce mathematical expressions of whathappens to the outgoing temperatures of the filling bed when the condensate flow changes or when theingoing temperature of the filling bed increases or decreases.

  • Ali, Sharafat
    et al.
    Linnaeus Univ, Sweden.
    Paul, Biplab
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Magnusson, Roger
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Ekström, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Pallier, Camille
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. RISE IVF, S-58188 Linkoping, Sweden.
    Jonson, Bo
    Linnaeus Univ, Sweden.
    Eklund, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Optical and mechanical properties of amorphous Mg-Si-O-N thin films deposited by reactive magnetron sputtering2019In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 372, p. 9-15Article in journal (Refereed)
    Abstract [en]

    In this work, amorphous thin films in Mg-Si-O-N system typically containing amp;gt; 15 at.% Mg and 35 at.% N were prepared in order to investigate especially the dependence of optical and mechanical properties on Mg composition. Reactive RF magnetron co-sputtering from magnesium and silicon targets were used for the deposition of Mg-Si-O-N thin films. Films were deposited on float glass, silica wafers and sapphire substrates in an Ar, N-2 and O-2 gas mixture. X-ray photoelectron spectroscopy, atomic force microscopy, scanning electron microscopy, spectroscopic ellipsometry, and nanoindentation were employed to characterize the composition, surface morphology, and properties of the films. The films consist of N and Mg contents up to 40 at.% and 28 at.%, respectively and have good adhesion to substrates and are chemically inert. The thickness and roughness of the films increased with increasing content of Mg. Both hardness (16-21 GPa) and reduced elastic modulus (120-176 GPa) are strongly correlated with the amount of Mg content. The refractive index up to 2.01 and extinction coefficient up to 0.18 were found to increase with Mg content. The optical band gap (3.1-4.3) decreases with increasing the Mg content. Thin film deposited at substrate temperature of 100 degrees C shows a lower value of hardness (10 GPa), refractive index (1.75), and higher values of reduced elastic modulus (124 GPa) as compared to the thin film deposited at 310 degrees C and 510 degrees C respectively, under identical synthesis parameters.

  • Johansson, Oskar
    et al.
    Linköping University, Department of Management and Engineering, Machine Design.
    Dahlgren Bjuhr, Anton
    Linköping University, Department of Management and Engineering, Machine Design.
    Concept development of a fixed sonobuoy launcher: A study to examine the feasibility of applying concept development methodology to solve an industry related problem2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

     Is it possible to apply concept development methodology to solve a real industrial problem? This study will examine if this is possible. Saab has ordered a concept which allows launching of a sonobuoy from a pressurized aircraft cabin, this is a perfect opportunity to test this theory because it is a real system with technical demands to ensure robustness and safety. The system needs to be operated in tight areas which is the reason no launcher available will be used, they do not fulfill this demand. There are also a number of demands that the concept needs to fulfill which must be ensured during the concept process. It is not common when developing a component that a thorough and systematical concept development process is carried out at Saab. Therefor it was interesting to see how it would work with a Saab related product.

    The concept development process was carried out thoroughly by researching known methods within the subject. It was decided that the process would not follow a singular methodology because there where no process that suited this study perfectly. The process used was decided to be parts from different literature where methods that suited the concept at the current state would be used. This was performed differently depending on the current state of the concept. For example the product requirement process were established in a different way than the concept generation because they are different, one is mostly gathering facts while the other is mainly a creative phase. Regardless of the step in the concept development process the objective was to always use some sort help from the methodology.

    A combination of lacking experience with the technical area and applying concept development methodology towards a industrial problem slowed down the process. The final concept were not as developed as the plan was from the start. To perform each step required more research than what was intended and some steps became an iterative process which also took time from the actual development. However, the actual process of setting up requirements, generating ideas and evaluating concepts should also be regarded as deliverable for this study. It is material that can be used for future development and this concept where never intended to be a finished design which mean it is useful material for the future.

    To use concept development methodology for this kind of projects is recommended based on this study. Foremost when the experience of the system is limited, it ensures that the solution space and requirements are examined more than it would have without the process. It also helps with decision making and when discussing a concept within the group which could lead to an agreement which it might not would have without the methods.

  • Holmqvist, Sofia
    et al.
    Linköping University, Department of Management and Engineering, Machine Design.
    Svensson, Moa
    Linköping University, Department of Management and Engineering, Machine Design.
    Development of an Indoor Cultivation Product for Restaurant Environments: Developing a Product Specification and Creating a Product Concept using User-Centered Design2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In today’s society there is a growing awareness of where food is produced and there is a trend to use locally grown produce in restaurants. One way for restaurants to differentiate themselves is to grow the produce inside the restaurant. This thesis has the aim on identifying the problems and user needs for an indoor cultivation solution and developing a new indoor cultivation product that solves the identified problems and meet the user needs. To achieve this aim, a usercentered design approach was utilised and the following three research questions were answered:

    • How can the needs of the user be translated into a product specification for indoor cultivation in restaurants?
    • What are the functionality, usability, and construction requirements for an indoor cultivation product in a restaurant?
    • What product concept can be designed to grow classic herbs in restaurants based on the needs of the user?

    To identify the needs interviews were performed with the users. The needs were then translated, together with the company’s needs, into a product specification. This was done in two steps, identifying the metrics and setting values. Some of the most important requirements are that a hydroponic system is used, that the product is easy to clean and is moveable.

    The product development process was iterative and included different ideation, development and evaluation methods. The users were involved in some of the evaluation methods to give input on the final design. Their opinion, together with evaluations based on the product specification, were used when choosing the final concept Lärad. Lärad uses a circulating hydroponic system and have three separate growing containers each containing 16 plants. The growing containers can be pulled out to enable easy access of the plants. Both the water system and the LED grow lights, that replaces natural sunlight, are controlled automatically to minimise the users’ involvement. To test the concept, to see how well the product specification is fulfilled, both a CAD model and a functional prototype were created. The results from the tests were, even at the concept stage, that 97% of all the tested requirements were fulfilled which shows that the concept is suitable for indoor cultivation in a restaurant environment. Some further work that includes refining the design and optimising for production will be needed to launch the product.

  • Reichenwallner, Christopher
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems.
    Wasborg, Daniel
    Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems.
    Control of a Hydraulic Hybrid System for Wheel Loaders2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In recent years many companies have investigated the use of hybrid technology due to the potential of increasing the driveline’s efficiency and thus reducing fuel consumption. Previous studies show that hydraulic hybrid technology can be favourable to use in construction machinery such as wheel loaders, which often operate in repetitive drive cycles and have high transient power demands. Parallel as well as Series hybrid configurations are both found suitable for wheel loader applications as the hybrid configurations can decrease the dependency on the torque converter. This project has investigated a novel hydraulic hybrid concept which utilizes the wheel loaders auxiliary pump as a supplement to enable both Series and Parallel hybrid operation. Impact of accumulator sizes has also been investigated, for which smaller accumulator sizes resembles a hydrostatic transmission. The hybrid concept has been evaluated by developing a wheel loader simulation model and a control system based on a rule-based energy management strategy. Simulation results indicate improved energy efficiency of up to 18.80 % for the Combined hybrid. Moreover, the accumulator sizes prove to have less impact on the energy efficiency. A hybrid system with decreased accumulator sizes shows improved energy efficiency of up to 16.40 %.

  • Westling, Hanna
    Linköping University, Department of Management and Engineering, Energy Systems.
    Kommuners roll i omställningen till ett hållbart energisystem: med fokus på arbetet gentemot medborgare och näringsliv2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A transition towards a sustainable energy system is of great importance given the climate changes which have been observed and the close link between climate changes and the energy system. Climate change is affecting the planet on a global level and it is therefore of vital importance that actors work together to reduce greenhouse gas emissions and achieve political goals, such as the United Nations' goal which state that the global temperature increase should be kept well below 2 degrees Celsius. 

    Given this background, the aim of the thesis has been to analyse the role of Swedish municipalities in the transition towards a sustainable energy system. The ability for Swedish municipalities to influence the transition has been divided into five areas; their own operations, their own companies, the local business sector, citizens and through cooperation. This thesis has focused on municipalities’ work addressing citizens and the business sector. Cooperation associated with citizens and businesses has also been included in the thesis.

    A literature search and an interview study were used as methods for data collection. The literature search has been conducted to generate a scientific foundation and give a context to the thesis. In the interview study, interviews were held with representatives from eight Swedish municipalities. The selection of municipalities has been strategic and based on The Swedish Association of Local Authorities’ division of municipalities into three main groups; A, B and C. The municipalities that have been interviewed are the City of Stockholm and the City of Malmö from group A, Linköping Municipality, Umeå Municipality and Eskilstuna Municipality from group B and Piteå Municipality, Mora Municipality and Markaryd Municipality from group C. The interview study has resulted in a description of the work related to the transition of the energy system in each municipality.

    It has been concluded that municipalities have an important role in Sweden's transition to a sustainable energy system. Furthermore, it has been indicated that actors at a local and regional level, such as municipalities, have contributed to reduced carbon dioxide emissions in Sweden. In their role, municipalities have the opportunity to influence the energy system through their own operations and their companies as well as other actors such as the local citizens and business sector. They are also able to influence the energy system through cooperation with other actors.

    In the work addressed to citizens and the business sector, the municipalities are able to use tools such as strategic documents, owner directives, physical and economic planning, municipal energy and climate advisors, means and support, and collaboration. They can also use policy instruments and nudging to create incentives in line with municipal targets and visions.

    The analysis shows that the municipalities mainly emphasized municipal energy and climate advisors and business networks as the tools they use in their work addressed to citizens and the business sector. One of the future opportunities and challenges is the municipalities' consideration to the role of citizens and businesses and their inclusion in the energy transition. Municipal self-government and the balance between local adaptation and collaboration are other crucial factors. Opportunities have also been observed by exploring topical areas such as consumption, resources and nudging. The main challenges seen by the municipalities are lack of resources and local adaptation from a national level. It is also important that their prerequisites are maintained consistently over time.

  • Kåge, Oliver
    Linköping University, Department of Management and Engineering, Malmstens Linköping University.
    Katten och jag: Möbler för både katt och människa2019Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    This is an investigative work about the relationship between cat and human in the home environment, interpreted through three objects. My work stems from the hypothesis that one can design furniture that increase wellbeing, whilst both being functional for cat and man. This will in turn strengthen the bond between cat and man.My research includes four parts. First being a collection of knowledge trough literature regarding the history of the cat, to better understand its needs and relation to man. Thereafter I show my market research regarding cat furnishing, to see what has been done and how others have designed with a similar question formulation as I.After that I have tried to asses how cats use furniture. I have based my research on how my cats use furniture and complemented with other cat owners’ views and thoughts to create an image of cats in general and their behaviour. My research is followed by a recital of my design process regarding the three objects. I report how I have designed each object to function for both cat and man.The result is one chair, a lamp and a table that all can be used by both cat and man separately, but most importantly together. I therefore answer the question that it is possible to design furniture that work for both cat and man, but whether my three objects are the answer may vary between people.

  • Lång, Marcus
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics.
    CFD-Method for 3D Aerodynamic Adjoint Simulations: For External Automotive Aerodynamics2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Today’s rules and regulations regarding emissions from combustion vehicles are very strict and the travel range per tank and/or charge, especially for electric vehicles, is a crucial factor which will always be considered by the customers. Hence, automotive manufacturers strive to boost fuel and battery economy. This can, to a great extent, be done by improving the aerodynamics of the vehicle for lower drag. The conventional CFD process for aerodynamic development is relatively time consuming and there is rarely enough timeor resources to find the optimal design in all regions of the vehicle. Hence, the adjoint solver was investigated to make the aerodynamic development process more efficient by providing sensitivities of the geometry with respect to drag force.

    The adjoint solver was investigated both through a literature review as well as by performing CFD and adjoint simulations. The CFD and adjoint simulations were performed using Fluent 2019 R1 and the realizable k-ε turbulence model. It was found that it is important to monitor surface sensitivities during the solution in addition to the adjoint residuals to assess convergence of the adjoint simulation. It is also recommended to analyse regions of high residuals in the domain to ensure that they are far away from the surface(s) of interest. Investigations regarding different stabilization schemes as well different meshes for the adjoint solver were performed.

    It was concluded that the residual minimization scheme (RMS) is the preferred stabilization scheme. It was found that a coarser mesh can be used to reduce localized transient behaviour if the adjoint solver has trouble converging. It was found that a simplified model of a fully detailed car geometry is necessary to reduce the complexity and the resolution of the mesh to be able to use the RMS and to avoid local instabilities. A proposed CFD and adjoint procedure with guidelines and recommendation was developed.

  • Ewerlöf, Sofia
    et al.
    Linköping University, Department of Management and Engineering, Environmental Technology and Management.
    Modig, Daniel
    Linköping University, Department of Management and Engineering, Environmental Technology and Management.
    Value Creation and Decreased Environmental Impact through Circular Economy-based Offerings: A Product-Service System Case Study2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis answers how a circular economy-based offering can be designed for increased value creation and decreased environmental impact, compared to a current offering. The study concerns a case company and their current offering of a fire safety solution, namely a 6 kg powder fire extinguisher. The concept Product-Service Systems is used as a base for the research and a foundation of the result.Throughout the study, the method Life Cycle Assessment (LCA) is used as a tool to evaluate and compare the current and the suggested solution in the sense of environmental sustainability amongst different impact categories. It provides a holistic perspective within the study which has been proven by theory to be an important factor when providing a circular economy-based offering. Another important factor is customising the offering to the specific case. This is attended to through an investigation of the company characteristics, the current offering and provider and customer values to find opportunities for the suggested solution. Opportunities found was e.g. a demand for an environmentally sustainable solution and existing infrastructure which can create valuein the future.The process includes, apart from the LCAs, interviews, a workshop at the case company and a survey addressed to end users. The use of visualisation tools such as actors map and Product-Service Blueprint benefits the understanding of both current and suggested solution and provides insights, evaluation and possible improvements. A cost calculation is made to evaluate if the solution is financially making business sense to the provider. Through this thesis, a circular economy-based solution which designs out waste is found. It is proven through the study and LCAs that this solution decreases the investigated environmental impact categories compared to the current existing solution. The suggested solution is based on a refilling process for circulating material which is established through the thesis to be theoretically feasible, hence needs consideration in order to be implementable in reality and make business sense to the provider.

  • Torabzadeh, M
    et al.
    Beckman Laser Institute and Medical Clinic, United States.; Univ. of California, Irvine, United States..
    Stockton, P
    Colorado State Univ., United States..
    Kennedy, G
    Beckman Laser Institute and Medical Clinic, United States..
    Saager, Rolf
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering.
    Durkin, AJ
    Beckman Laser Institute and Medical Clinic, United States.; Univ. of California, Irvine, United States..
    Bartels, R
    Colorado State Univ., United States..
    Tromberg, B
    Beckman Laser Institute and Medical Clinic, United States.; Univ. of California, Irvine, United States..
    Hyperspectral imaging in the spatial frequency domain with a supercontinuum source.2019In: Journal of Biomedical Optics, ISSN 1083-3668, E-ISSN 1560-2281, Vol. 24, no 7, p. StartPage-EndPageArticle in journal (Refereed)
    Abstract [en]

    We introduce a method for quantitative hyperspectral optical imaging in the spatial frequency domain (hs-SFDI) to image tissue absorption (μa) and reduced scattering (μs') parameters over a broad spectral range. The hs-SFDI utilizes principles of spatial scanning of the spectrally dispersed output of a supercontinuum laser that is sinusoidally projected onto the tissue using a digital micromirror device. A scientific complementary metal-oxide-semiconductor camera is used for capturing images that are demodulated and analyzed using SFDI computational models. The hs-SFDI performance is validated using tissue-simulating phantoms over a range of μa and μs' values. Quantitative hs-SFDI images are obtained from an ex-vivo beef sample to spatially resolve concentrations of oxy-, deoxy-, and met-hemoglobin, as well as water and fat fractions. Our results demonstrate that the hs-SFDI can quantitatively image tissue optical properties with 1000 spectral bins in the 580- to 950-nm range over a wide, scalable field of view. With an average accuracy of 6.7% and 12.3% in μa and μs', respectively, compared to conventional methods, hs-SFDI offers a promising approach for quantitative hyperspectral tissue optical imaging.

  • Nordström, Jan
    et al.
    Linköping University, Department of Mathematics, Computational Mathematics. Linköping University, Faculty of Science & Engineering.
    Winters, Andrew Ross
    Linköping University, Department of Mathematics, Computational Mathematics. Linköping University, Faculty of Science & Engineering.
    Energy versus entropy estimates for nonlinear hyperbolic systems of equations2019Report (Other academic)
    Abstract [en]

    We compare and contrast information provided by the energy analysis of Kreiss and the entropy theory of Tadmor for systems of nonlinear hyperbolic conservation laws. The two-dimensional nonlinear shallow water equations are used to highlight the similarities and differences since the total energy of the system is a mathematical entropy function. We demonstrate that the classical energy method is consistent with the entropy analysis, but significantly more fundamental as it guides proper boundary treatments. In particular, the energy analysis provides information on what type of and how many boundary conditions are required, which is lacking in the entropy analysis. For the shallow water system we determine the number and the type of boundary conditions needed for subcritical and supercritical flows on a general domain. As eigenvalues are augmented in the nonlinear analysis, we find that a flow may be classified as subcritical, but the treatment of the boundary resembles that of a supercritical flow. Because of this, we show that the nonlinear energy analysis leads to a different number of boundary conditions compared with the linear energy analysis. We also demonstrate that the entropy estimate leads to erroneous boundary treatments by over specifying and/or under specifying boundary data causing the loss of existence and/or energy bound, respectively. Our analysis reveals that the nonlinear energy analysis is the only one that provides an estimate for open boundaries. Both the entropy and linear energy analysis fail.

  • Thellman, Sam
    et al.
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, Faculty of Arts and Sciences.
    Ziemke, Tom
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, Faculty of Science & Engineering.
    The Intentional Stance Toward Robots: Conceptual and Methodological Considerations2019In: CogSci'19. Proceedings of the 41st Annual Conference of the Cognitive Science Society / [ed] A.K. Goel, C.M. Seifert, & C. Freksa, 2019, p. 1097-1103Conference paper (Refereed)
    Abstract [en]

    It is well known that people tend to anthropomorphize in interpretationsand explanations of the behavior of robots and otherinteractive artifacts. Scientific discussions of this phenomenontend to confuse the overlapping notions of folk psychology,theory of mind, and the intentional stance. We provide a clarificationof the terminology, outline different research questions,and propose a methodology for making progress in studyingthe intentional stance toward robots empirically.

  • Bastuck, Manuel
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Improving the Performance of Gas Sensor Systems with Advanced Data Evaluation, Operation, and Calibration Methods2019Doctoral thesis, monograph (Other academic)
    Abstract [en]

    In order to facilitate the widespread use of gas sensors, some challenges must still be overcome. Many of those are related to the reliable quantification of ultra-low concentrations of specific compounds in a background of other gases. This thesis focuses on three important items in the measurement chain: sensor material and operating modes, evaluation of the resulting data, and test gas generation for efficient sensor calibration.

    New operating modes and materials for gas-sensitive field-effect transistors have been investigated. Tungsten trioxide as gate oxide can improve the selectivity to hazardous volatile organic compounds like naphthalene even in a strong and variable ethanol background. The influence of gate bias and ultraviolet light has been studied with respect to the transport of oxygen anions on the sensor surface and was used to improve classification and quantification of different gases.

    DAV3E, an internationally recognized MATLAB-based toolbox for the evaluation of cyclic sensor data, has been developed and published as opensource. It provides a user-friendly graphical interface and specially tailored algorithms from multivariate statistics.

    The laboratory tests conducted during this project have been extended with an interlaboratory study and a field test, both yielding valuable insights for future, more complex sensor calibration. A novel, efficient calibration approach has been proposed and evaluated with ten different gas sensor systems. 

  • Shi, Yuchen
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Höjer, Pontus
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Yazdi, Gholamreza
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Sun, Jianwu W.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    A comparative study of high-quality C-face and Si-face 3C-SiC(1 1 1) grown on off-oriented 4H-SiC substrates2019In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 52, no 34Article in journal (Refereed)
    Abstract [en]

    We present a comparative study of the C-face and Si-face of 3C-SiC(111) grown on off-oriented 4H-SiC substrates by the sublimation epitaxy. By the lateral enlargement method, we demonstrate that the high-quality bulk-like C-face 3C-SiC with thickness of ~1 mm can be grown over a large single domain without double positioning boundaries (DPBs), which are known to have a strongly negative impact on the electronic properties of the material. Moreover, the C-face sample exhibits a smoother surface with one unit cell height steps while the surface of the Si-face sample exhibits steps twice as high as on the C-face due to step-bunching. High-resolution XRD and low temperature photoluminescence measurements show that C-face 3C-SiC can reach the same high crystalline quality as the Si-face 3C-SiC. Furthermore, cross-section studies of the C- and Si-face 3C-SiC demonstrate that in both cases an initial homoepitaxial 4H-SiC layer followed by a polytype transition layer are formed prior to the formation and lateral expansion of 3C-SiC layer. However, the transition layer in the C-face sample is extending along the step-flow direction less than that on the Si-face sample, giving rise to a more fairly consistent crystalline quality 3C-SiC epilayer over the whole sample compared to the Si-face 3C-SiC where more defects appeared on the surface at the edge. This facilitates the lateral enlargement of 3C-SiC growth on hexagonal SiC substrates.

  • Bandyopadhyay, Souvik K.
    et al.
    GlaxoSmithKline Asia Pvt. Ltd., Bangalore, India.
    Azharuddin, Mohammad
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Chemistry. Linköping University, Faculty of Medicine and Health Sciences.
    Dasgupta, Anjan K.
    Department of Biochemistry, University of Calcutta, Kolkata, India.
    Ganguli, Bhaswati
    Department of Statistics, University of Calcutta, Kolkata, India.
    SenRoy, Sugata
    Department of Statistics, University of Calcutta, Kolkata, India.
    Patra, Hirak K.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences. Wolfson College, University of Cambridge, Cambridge, United Kingdom; Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, United Kingdom.
    Deb, Suryyani
    Department of Biotechnology, Maulana Abul Kalam Azad University of Technology, Kolkata, India.
    Probing ADP Induced Aggregation Kinetics During Platelet-Nanoparticle Interactions: Functional Dynamics Analysis to Rationalize Safety and Benefits2019In: Frontiers in Bioengineering and Biotechnology, E-ISSN 2296-4185, Vol. 7, p. 163-Article in journal (Refereed)
    Abstract [en]

    Platelets, one of the most sensitive blood cells, can be activated by a range of external and internal stimuli including physical, chemical, physiological, and/or non-physiological agents. Platelets need to respond promptly during injury to maintain blood haemostasis. The time profile of platelet aggregation is very complex, especially in the presence of the agonist adenosine 5’-diphosphate (ADP), and difficult to probe such complexity using traditional linear dose response models. In the present study, we explored functional data to characterise the pattern of platelet aggregation over time in response to nanoparticle induced perturbations. This has obviated the need to represent the pattern of aggregation by a single summary measure and allowed us to treat the entire aggregation profile over time as the response. The modelling has been performed in a flexible manner, without any imposition of shape restrictions on the curve, allowing smooth platelet aggregation over time. The use of a probabilistic framework not only allowed statistical prediction and inference of the aggregation signatures, but also provided a novel method for the estimation of higher order derivatives of the curve, thereby allowing plausible estimation of the extent and rate of platelet aggregation kinetics over time. In the present study, we focused on the estimated first derivative of the curve obtained from the platelet optical aggregometric profile over time, and used it to discern the underlying kinetics as well as to study the effects of ADP dosage and perturbation with gold nanoparticles. In addition, our method allowed the quantification of the extent of inter-individual signature variations.

  • Rostedt, Josefin
    Linköping University, Department of Social and Welfare Studies. Linköping University, Faculty of Educational Sciences.
    Förskollärare planerar barns möten med matematik: Ett reflektivt skoldidaktiskt perspektiv2019Licentiate thesis, monograph (Other academic)
    Abstract [en]

    Nyckelord: förskola, planering, didaktik, matematikundervisning  This Licentiate thesis focuses on planning in Swedish preschool. The aim is to describe and analyze pre-school teacher's authentic planning of children's meetings with mathematics. The theoretical framing of the study consists of the reflective school didactic theory emphasizing, regardless of school form, teachers' responsibility for teaching. With the reflective school didactic theory, the planning process is described as important for teaching. The planning process consists of three pedagogical activities: intention – action – reflection. This study focuses on the pedagogical work that takes place away from action, which makes intention and reflection to the central concept of the study.

    The empirical material of the study has been produced using participatory observation. Field work has been carried out in a preschool on part time for two semesters in the academic year 2012/13 in a regular and authentic planning conversation. The results show that the pre-school teachers do plan children's meetings with mathematics by taking their starting point in reflection on planned and documented pedagogical events. There is thus a link between intention and reflection. The result shows that the team has construct a planning model of their own. The planning is not based on explicit expressed goal formulations about what to learn. The reasoning of possible learning comes in as part of their conversations about activities. The result also shows that planning creates conditions for meetings with a multitude of mathematics. However, the results discussion shows that there is room to develop reasoning about the ways in which children can make transitions from everyday mathematical representations to more abstract. The result also shows that there is a need to develop a mathematics didactic language in preschool.

    Nyckelord: förskola, planering, didaktik, matematikundervisning  This Licentiate thesis focuses on planning in Swedish preschool. The aim is to describe and analyze pre-school teacher's authentic planning of children's meetings with mathematics. The theoretical framing of the study consists of the reflective school didactic theory emphasizing, regardless of school form, teachers' responsibility for teaching. With the reflective school didactic theory, the planning process is described as important for teaching. The planning process consists of three pedagogical activities: intention – action – reflection. This study focuses on the pedagogical work that takes place away from action, which makes intention and reflection to the central concept of the study.

    The empirical material of the study has been produced using participatory observation. Field work has been carried out in a preschool on part time for two semesters in the academic year 2012/13 in a regular and authentic planning conversation. The results show that the pre-school teachers do plan children's meetings with mathematics by taking their starting point in reflection on planned and documented pedagogical events. There is thus a link between intention and reflection. The result shows that the team has construct a planning model of their own. The planning is not based on explicit expressed goal formulations about what to learn. The reasoning of possible learning comes in as part of their conversations about activities. The result also shows that planning creates conditions for meetings with a multitude of mathematics. However, the results discussion shows that there is room to develop reasoning about the ways in which children can make transitions from everyday mathematical representations to more abstract. The result also shows that there is a need to develop a mathematics didactic language in preschool.

  • Carlsson, Rickard
    et al.
    Linnaeus University, Sweden.
    Danielsson, Henrik
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences. Linköping University, The Swedish Institute for Disability Research.
    Heene, Moritz
    Ludwig-Maximilians-University Munich, Germany.
    Innes-Ker, Åse
    Lund University, Sweden.
    Lakensël, Daniel
    Eindhoven University of Technology, The Netherlands.
    Schimmack, Ulrich
    University of Toronto, Canada.
    Schönbrodt, Felix D
    Ludwig-Maximilians-University Munich, Germany.
    Van Assen, Marcel
    Tilburg University and Utrecht University.
    Weinstein, Yana
    University of Massachusetts, Lowell, USA.
    Inaugural Editorial of Meta-Psychology2017In: Meta-Psychology, ISSN 2003-2714, Vol. 1Article in journal (Other academic)
  • Public defence: 2019-09-06 09:00 Originalet, Qulturum, Jönköping
    Taxbro, Knut
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences.
    Vascular access in cancer patients – clinical implications2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Central venous catheters (CVC) are vital for patients receiving chemotherapy not compatible with peripheral infusion. Thousands of centrally and peripherally inserted central venous catheters are inserted into patients with cancer each year. All types of intravascular catheters are associated with complications. These complications may be divided into infectious, thrombotic, mechanical and occlusive events. All of these events have the potential to harm patients and cause additional expense for the health-care system. Furthermore, the above-mentioned complications are largely avoidable through proper patient selection, insertion technique, hygiene precautions and catheter maintenance.

    Catheter-related infections and deep venous thrombosis are the two most common and feared CVC related complications. Infection in a catheter can cause lifethreatening bacteraemia, and thrombosis can lead to pulmonary embolisation, post-thrombotic syndrome and stenosis of the vessel affected. Many studies describing methods to minimise infectious complications associated with central venous catheters have been carried out. These methods appear to have been implemented in most modern advanced healthcare facilities resulting in a continual decrease in catheter-related infections over the last two decades. New implantation techniques, fewer infections and better catheter materials are likely to have contributed to the reduction in the incidence of catheter-related deep venous thrombosis (CR-DVT). Peripherally inserted central venous catheters (PICC) and subcutaneously implanted vascular access ports (PORT) are two very commonly used catheter devices for delivery of chemotherapy. International guidelines are unclear as to which device to choose due to the paucity of controlled trials.

    The aim of this thesis was to study complications related to central venous access devices used over long periods of time, usually for the delivery of chemotherapy. Vascular access in cancer patients – clinical implications We prospectively studied PORT complications (Study 1) over a six-month follow- up period. In Study 2, we assessed the number of common CVC-related micro- organisms that are transferred across PORT membrane contaminated by a controlled suspension of micro-organisms when a non-coring access needle is inserted using two different techniques. In the largest randomised controlled trial published on this topic (Study 3), we compared PICC with PORT regarding CRDVT and other catheter-related complications. The economic implications of using PICC or PORT were assessed from health-care system´s perspective (Study 4), using data on adverse events and clinical factors (implantation, treatments and dwell-time) from Study 3.

    Chemotherapy against various forms of cancer is very common. Implantation of PORT is one of the ten most common surgical procedures in Sweden according to the Swedish Perioperative Register. Hence, the topic in this thesis may be clinically relevant to many patients and their health care providers.

    We found that the incidence of catheter-related blood stream infection was very low in the cohorts studied. In general, PICCs are associated with significantly more CR-DVTs and adverse events than PORTs. The cost to the health-care system when using PICC is higher than for PORT when complications are included. Given the choice, patients about to commence chemotherapy appear to prefer PORT to PICC. PORT implantation is more painful than PICC insertion, but PICC appears to influence activities of daily life more than PORT.

    List of papers
    1. A prospective observational study on 249 subcutaneous central vein access ports in a Swedish county hospital
    Open this publication in new window or tab >>A prospective observational study on 249 subcutaneous central vein access ports in a Swedish county hospital
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    2013 (English)In: Acta Oncologica, ISSN 0284-186X, E-ISSN 1651-226X, Vol. 52, no 5, p. 893-901Article in journal (Refereed) Published
    Abstract [en]

    Background. Reliable central vein access is a fundamental issue in modern advanced oncological care. The aim of this study was to determine the incidence of complications and patient perception regarding central vein access ports. Methods. We prospectively studied 249 single lumen access ports implanted between 1 July 2008 and 15 March 2010 in a mixed patient population at a 500-bed secondary level hospital in Sweden. We determined the number of catheter days, infection rate and mechanical complications, as well as patient satisfaction regarding the access port, over a six-month follow-up period. Results. Two hundred and forty-four different patients received 249 ports yielding a total of 37 763 catheter days. Ultrasound and fluoroscopic guidance was used in 98% of procedures. Vein access was obtained percutanously by an anaesthesiologist in all cases. There was no case of pneumo- or haemothorax. The incidence of catheter-related bloodstream infection, was 0.05/1000 catheter days and the incidence of pocket/tunnel infection was 0.39/1000 catheter days. Clinically apparent deep vein thrombosis occurred in four patients (1.6%). Patient satisfaction was overall high. Conclusion. These results confirm that our team-based approach with written easily accessible evidence-based guidelines and a structured education programme leads to a very low complication rate and a high degree of patient satisfaction.

    Place, publisher, year, edition, pages
    Informa Healthcare, 2013
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-93959 (URN)10.3109/0284186X.2013.770601 (DOI)000318655300003 ()
    Note

    Funding Agencies|Futurum - the Academy for Healthcare, Jonkoping County Council, Jonkoping, Sweden||

    Available from: 2013-06-13 Created: 2013-06-13 Last updated: 2019-07-23
    2. Clinical impact of peripherally inserted central catheters vs implanted port catheters in patients with cancer: an open-label, randomised, two-centre trial
    Open this publication in new window or tab >>Clinical impact of peripherally inserted central catheters vs implanted port catheters in patients with cancer: an open-label, randomised, two-centre trial
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    2019 (English)In: British Journal of Anaesthesia, ISSN 0007-0912, E-ISSN 1471-6771, Vol. 122, no 6, p. 734-741Article in journal (Refereed) Published
    Abstract [en]

    Background

    Centrally inserted totally implanted vascular access ports (PORTs) and peripherally inserted central catheters (PICCs) are widely used for the administration of chemotherapy. Our aim was to study the incidence of catheter-related deep venous thrombosis in patients with cancer receiving chemotherapy through either a PICC or a PORT.

    Methods

    Adults with non-haematological cancer (mainly breast and colorectal) from two Swedish oncology centres were included and followed for up to 1 yr. Patients were randomly assigned to receive a single-lumen PICC or PORT. The primary end point was the occurrence of a clinically significant catheter-related deep venous thrombosis, and the secondary end point was a composite of adverse events related to the catheter: insertion complication, thrombosis, occlusion, infection, and mechanical problems.

    Results

    The trial recruited 399 participants (PICC, n=201; PORT, n=198) between March 2013 and February 2017. The PICCs were associated with 16 (8%) deep venous thromboses compared with two (1%) in the PORT group (HR=10.2; 95% confidence interval, 2.3–44.6; P=0.002). The overall incidence of composite adverse events was higher for patients with a PICC compared with those with a PORT (HR=2.7; 95% confidence interval, 1.6–4.6; P<0.001).

    Conclusions

    PICCs are associated with higher risk for catheter-related deep venous thrombosis and other adverse events when compared with PORTs. This increased risk should be considered when choosing a vascular access device for chemotherapy, especially in patients with solid malignancy.

    Place, publisher, year, edition, pages
    Elsevier, 2019
    Keywords
    central venous catheter; central venous catheter thrombosis; peripherally inserted central catheter line insertion; vascular access devices
    National Category
    Surgery
    Identifiers
    urn:nbn:se:liu:diva-158319 (URN)10.1016/j.bja.2019.01.038 (DOI)000467806400034 ()31005243 (PubMedID)2-s2.0-85064326103 (Scopus ID)
    Note

    Funding Agencies|Futurum (Academy for Healthcare, Jonkoping County Council, Sweden) [767451]; FORSS (Research Council in South East Sweden) [295881]

    Available from: 2019-07-02 Created: 2019-07-02 Last updated: 2019-08-12Bibliographically approved
  • Public defence: 2019-09-02 13:00 Belladonnasalen, Linköping
    Bergkvist, Max
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Studies on Polarised Light Spectroscopy2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis project focuses on measurements of dermal microcirculation during vascular provocations with polarised light spectroscopy. This is done with a non-invasive method commercially available as Tissue viability imaging (TiVi) which measures concentration and oxygenation of red blood cells in the papillary dermis. Three studies were done with human subjects and one with an animal model, to validate and compare the TiVi technique with laser Doppler flowmetry, which is an established method of measuring dermal microcirculation.

    The TiVi consists of a digital camera with polarisation filters in front of the flash and lens, with software for analysis of the picture. When taking a picture with the TiVi, the polarised light that is reflected on the skin surface is absorbed by the second filter over the lens (which is perpendicular to the first filter) but a portion of light penetrates the surface of the skin and is scattered when it is reflected on tissue components. This makes the light depolarised, passes the second filter, and produces a picture for analysis. The red blood cell (RBC) has a distinct absorption pattern that differs between red and green colour compared to melanin and other components of tissue. This difference is used by the software that calculates differences in each picture element and produces a measure of output which is proportional to the concentration of red blood cells. The oxygenation of RBC can also be calculated, as there is a difference in absorption depending on oxygen state.

    The first paper takes up possible sources of error such as ambient light, and the angle and distance of the camera. The main experiment was to investigate how the local heating reaction is detected with TiVi compared to LDF.

    In the second paper arterial and venous stasis are examined in healthy subjects with TiVi.

    The Third paper is an animal study where skin flaps were raised on pigs, and the vascular pedicle is isolated to enable control of inflow and outflow of blood.The measurements were made during partial venous, total venous, and total arterial occlusion. The TiVi recorded changes in the concentration of RBC, oxygenation and heterogeneity and the results were compared with those of laser Doppler flowmetry.

    In the fourth paper oxygenation and deoxygenation of RBC: s was studied. Studies were made on the forearms of healthy subjects who were exposed to arterial and venous occlusion. Simultaneous measurements were made with TiVi and Enhanced perfusion and oxygen saturation or EPOS, which is a new device that combines laser Doppler flowmetry and diffuse reflectance spectroscopy in one probe.

    With TiVi, one can measure RBC concentration and oxygenation in the area of an entire picture or in one or multiple user defined regions of interest (ROI). Methods such as laser Doppler flowmetry makes single point measurements, which is a potential source of error both because of the heterogeneity of the microcirculation, and that the circulation be insufficient in the margins of the investigated area. TiVi has been able to measure venous stasis more accurately than laser Doppler flowmetry, and venous stasis is the more common reason for flaps to fail.

    The TiVi is an accurate way to measure the concentration of RBC and trends in oxygenation of the dermal microcirculation. It has interesting possible applications for microvascular and dermatological research, monitoring of flaps, and diagnosis of peripheral vascular disease. Future clinical studies are needed as well as development of the user interface.  

    List of papers
    1. Polarized Light Spectroscopy for Measurement of the Microvascular Response to Local Heating at Multiple Skin Sites
    Open this publication in new window or tab >>Polarized Light Spectroscopy for Measurement of the Microvascular Response to Local Heating at Multiple Skin Sites
    2012 (English)In: Microcirculation, ISSN 1073-9688, E-ISSN 1549-8719, Vol. 19, no 8, p. 705-713Article in journal (Refereed) Published
    Abstract [en]

    Objective: To evaluate whether TiVi, a technique based on polarized light, could measure the change in RBC concentration during local heating in healthy volunteers. Methods: Using a custom-made transparent heater, forearm skin was heated to 42 degrees C for 40 minutes while the change in RBC concentration was measured with TiVi. The perfusion response during local heating was measured at the same time with Laser Doppler flowmetry. Results: Mean RBC concentration increased (91 +/- 34 vs. 51 +/- 34 A.U. at baseline, p less than 0.001). The spatial heterogeneity of the RBC concentration in the measured skin areas was 26 +/- 6.4% at baseline, and 23 +/- 4.6% after 40 minutes of heating. The mean RBC concentrations in two skin sites were highly correlated (0.98 at baseline and 0.96 after 40 minutes of heating). The change in RBC concentration was less than the change in perfusion, measured with LDF. Unlike with LDF, a neurally mediated peak was not observed with TiVi in most of the test subjects. Conclusions: TiVi is a valuable technique for measuring the microvascular response to local heating in the skin, and offers a high reproducibility for simultaneous measurements at different skin sites, provided carefully controlled experiments are ensured.

    Place, publisher, year, edition, pages
    Informa Healthcare / John Wiley and Sons, 2012
    Keywords
    tissue viability imaging; polarization light spectroscopy; local heating; red blood cell concentration; reproducibility
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-87225 (URN)10.1111/j.1549-8719.2012.00203.x (DOI)000311373400004 ()
    Available from: 2013-01-14 Created: 2013-01-14 Last updated: 2019-07-23
    2. Assessment of microcirculation of the skin using Tissue Viability Imaging: A promising technique for detecting venous stasis in the skin
    Open this publication in new window or tab >>Assessment of microcirculation of the skin using Tissue Viability Imaging: A promising technique for detecting venous stasis in the skin
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    2015 (English)In: Microvascular Research, ISSN 0026-2862, E-ISSN 1095-9319, Vol. 101, p. 20-25Article in journal (Refereed) Published
    Abstract [en]

    Background: : Venous occlusion in the skin is difficult to detect by existing measurement techniques. Our aim was to find out whether Tissue Viability Imaging (TiVi) was better at detecting venous occlusion by comparing it with results of laser Doppler flowmetry (LDF) during graded arterial and venous stasis in human forearm skin. Methods: : Arterial and venous occlusions were simulated in 10 healthy volunteers by inflating a blood pressure cuff around the upper right arm. Changes in the concentration of red blood cells (RBC) were measured using TiVi, while skin perfusion and concentration of moving red blood cells (CMBC) were measured using static indices of LDF during exsanguination and subsequent arterial occlusion, postocclusive reactive hyperaemia, and graded increasing and decreasing venous stasis. Results: : During arterial occlusion there was a significant reduction in the mean concentration of RBC from baseline, as well as in perfusion and CMBC (p less than 0.008). Venous occlusion resulted in a significant 28% increase in the concentration of RBC (p = 0.002), but no significant change in perfusion (mean change -14%) while CMBC decreased significantly by 24% (p = 0.02). With stepwise increasing occlusion pressures there was a significant rise in the TiVi index and reduction in perfusion (p = 0.008), while the reverse was seen when venous flow was gradually restored. Conclusion: : The concentration of RBC measured with TiVi changes rapidly and consistently during both total and partial arterial and venous occlusions, while the changes in perfusion, measured by LDF, were less consistent This suggests that TiVi could be a more useful, non-invasive clinical monitoring tool for detecting venous stasis in the skin than LDF.

    Place, publisher, year, edition, pages
    Elsevier, 2015
    Keywords
    Tissue viability imaging; Laser Doppler flowmetry; Post-occusive hyperaemia; Venous occlusion; Arterial occlusion
    National Category
    Clinical Medicine
    Identifiers
    urn:nbn:se:liu:diva-121302 (URN)10.1016/j.mvr.2015.06.002 (DOI)000360028500004 ()26092681 (PubMedID)
    Note

    Funding Agencies|County Council of Ostergotland, Sweden [2014JZ0004]

    Available from: 2015-09-16 Created: 2015-09-14 Last updated: 2019-07-23Bibliographically approved
    3. Vascular Occlusion in a Porcine Flap Model: Effects on Blood Cell Concentration and Oxygenation.
    Open this publication in new window or tab >>Vascular Occlusion in a Porcine Flap Model: Effects on Blood Cell Concentration and Oxygenation.
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    2017 (English)In: Plastic and reconstructive surgery. Global open, ISSN 2169-7574, Vol. 5, no 11, article id e1531Article in journal (Refereed) Published
    Abstract [en]

    Background: Venous congestion in skin flaps is difficult to detect. This study evaluated the ability of tissue viability imaging (TiVi) to measure changes in the concentration of red blood cells (CRBC), oxygenation, and heterogeneity during vascular provocations in a porcine fasciocutaneous flap model.

    Methods: In 5 pigs, cranial gluteal artery perforator flaps were raised (8 flaps in 5 pigs). The arterial and venous blood flow was monitored with ultrasonic flow probes. CRBC, tissue oxygenation, and heterogeneity in the skin were monitored with TiVi during baseline, 50% and 100% venous occlusion, recovery, 100% arterial occlusion and final recovery, thereby simulating venous and arterial occlusion of a free fasciocutaneous flap. A laser Doppler probe was used as a reference for microvascular perfusion in the flap.

    Results: During partial and complete venous occlusion, increases in CRBC were seen in different regions of the flap. They were more pronounced in the distal part. During complete arterial occlusion, CRBC decreased in all but the most distal parts of the flap. There were also increases in tissue oxygenation and heterogeneity during venous occlusion.

    Conclusions: TiVi measures regional changes in CRBC in the skin of the flap during arterial and venous occlusion, as well as an increase in oxygenated hemoglobin during venous occlusion that may be the result of reduced metabolism and impaired delivery of oxygen to the tissue. TiVi may provide a promising method for measuring flap viability because it is hand-held, easy to-use, and provides spatial information on venous congestion.

    Place, publisher, year, edition, pages
    Wolters Kluwer, 2017
    National Category
    Radiology, Nuclear Medicine and Medical Imaging Surgery
    Identifiers
    urn:nbn:se:liu:diva-145391 (URN)10.1097/GOX.0000000000001531 (DOI)29263951 (PubMedID)2-s2.0-85038559789 (Scopus ID)
    Available from: 2018-02-27 Created: 2018-02-27 Last updated: 2019-07-23Bibliographically approved
  • Ryösä, A.
    et al.
    Department of Orthopaedics and Traumatology, Turku University Central Hospital, Turku, Finland.
    Kukkonen, J.
    Department of Surgery, Division of Orthopaedics and Traumatology, Satakunnan Keskussairaala, Pori, Finland.
    Björnsson Hallgren, Hanna
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Orthopaedics in Linköping.
    Moosmayer, S.
    Department of Orthopaedic Surgery, Martina Hansens Hospital, Sandvika, Norway.
    Holmgren, Theresa
    Linköping University, Department of Medical and Health Sciences, Division of Physiotherapy. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Orthopaedics in Linköping.
    Ranebo, M.
    Lanssjukhuset Kalmar Ortopedkliniken, Kalmar, Sweden.
    Bøe, B.
    Division of Orthopaedic Surgery, Oslo Universitetssykehus Ulleval, Oslo, Norway.
    Äärimaa, V.
    Department of Orthopaedics and Traumatology, Turku University Central Hospital, Turku, Finland.
    Acute Cuff Tear Repair Trial (ACCURATE): Protocol for a multicentre, randomised, placebo-controlled trial on the efficacy of arthroscopic rotator cuff repair2019In: BMJ Open, ISSN 2044-6055, E-ISSN 2044-6055, Vol. 9, no 5, article id e025022Article in journal (Refereed)
    Abstract [en]

    Introduction Rotator cuff tear is a very common and disabling condition that can be related to acute trauma. Rotator cuff tear surgery is a well-established form of treatment in acute rotator cuff tears. Despite its widespread use and almost a gold standard position, the efficacy of an arthroscopic rotator cuff repair is still unknown. The objective of this trial is to investigate the difference in outcome between arthroscopic rotator cuff repair and inspection of the shoulder joint defined as placebo surgery in patients 45-70 years of age with an acute rotator tear related to trauma. Methods and analysis Acute Cuff Tear Repair Trial (ACCURATE) is a randomised, placebo-controlled, multicentre efficacy trial with sample size of 180 patients. Concealed allocation is done in 1:1 ratio. The randomisation is stratified according to participating hospital, gender and baseline Western Ontario Rotator Cuff Index (WORC). Both groups receive the same standardised postoperative treatment and physiotherapy. The primary outcome measure is the change in WORC score from baseline to 2-year follow-up. Secondary outcome measures include Constant-Murley Score, the Numerical Rating Scale for pain, subjective patient satisfaction and the health-related quality of life instrument 15 dimensions (15D). Patients and outcome assessors are blinded from the allocated intervention. The primary analysis of results will be conducted according to intention-To-Treat analysis. Ethics and dissemination The study protocol for this clinical trial has been approved by the Ethics Committee of the Hospital District of Southwest Finland and Regional Ethics Committee in Linköping Sweden and Regional Committees for Medical and Health Research Ethics South East in Norway. Every recruiting centre will apply local research approvals. The results of this study will be submitted for publication in peer-reviewed journals. Trial registration number NCT02885714; Pre-results. © Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.