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  • 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 Kumar
    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 hemostasis. The time profile of platelet aggregation is very complex, especially in the presence of the agonist adenosine 5′-diphosphate (ADP), and it is difficult to probe such complexity using traditional linear dose response models. In the present study, we explored functional analysis techniques to characterize 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 modeling was 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. Our findings indicated several hidden features and showed a mixture of zero and first order kinetics interrupted by a metastable zero order ADP dose dependent process. In addition, we showed that the two first order kinetic constants were ADP dependent. However, we were able to perturb the overall kinetic pattern using gold nanoparticles, which resulted in autocatalytic aggregation with a higher aggregate mass and which facilitated the aggregation rate.

  • 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.