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  • Zaenker, Tobias
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering. Aalto University, Department of Electrical Engineering and Automation.
    Hypermaps: Beyond occupancy grids2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Intelligent and autonomous robotic applications often require robots to have more information about their environment than provided by traditional occupancy maps. An example are semantic maps, which provide qualitative descriptions of the environment. While research in the area of semantic mapping has been performed, most robotic frameworks still offer only occupancy maps.

    In this thesis, a framework is developed to handle multi-layered 2D maps in ROS. The framework offers occupancy and semantic layers, but can be extended with new layer types in the future. Furthermore, an algorithm to automatically generate semantic maps from RGB-D images is presented.

    Software tests were performed to check if the framework fulfills all set requirements. It was shown that the requirements are accomplished. Furthermore, the semantic mapping algorithm was evaluated with different configurations in two test environments, a laboratory and a floor. While the object shapes of the generated semantic maps were not always accurate and some false detections occurred, most objects were successfully detected and placed on the semantic map. Possible ways to improve the accuracy of the mapping in the future are discussed.

  • Riström, Anton
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Naronikar, Aditya
    Linköping University.
    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 − ε 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.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 − ε 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. 

  • Huber, Nikolaus
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Porting Zephyr RTOS to the LEON/GRLIB SoC SPARC v8 architecture2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aim of this thesis is to create a port of the Zephyr realtime operating systemfor the LEON processor platform. The LEON is a frequently used computing corefor spaceflight applications, with ample flight heritage. It is based upon the wellestablished SPARC v8 instruction set, and offers many extensions to ease softwaredevelopment and increase overall processor performance. An overview of the nec-essary steps towards a functional architecture port is given in this report. Specialemphasis is put upon the interrupt handling and context switching. One LEONspecific feature introduced with the GR716 LEON3-FT microcontroller, registerwindow partitioning, is used to increase the performance of the context switchingmechanism in the operating system. By using this feature, context switching timehas shown to decrease significantly, while easing verification of the overall softwaresystem by providing dedicated partitions for tasks with hard realtime requirements.

  • Badami, Muhammad Ali
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Design of a FEEP Thruster for Micro-/Nano-Satellites2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    CubeSat development has seen a rise since the first launch in 2003 due to faster design process and low launch costs. It has played a vital role in providing access to space to small start-ups and academic organizations with low budgets. It has also enabled the testing of different upcoming technologies in space and has helped in providing hands-on experience to students taking part in design of such platforms. University of Pisa, in collaboration with SITAEL, has also taken an initiative to design and develop a CubeSat to test the FEEP thruster, design of which is presented in the thesis. A FEEP system was designed to fit within 1U dimensions and with a dry mass of approximately 820 grams. The system is based on slit emitter which provides an advantage over already available technologies in the market which uses needle emitters. Slit emitter scan achieve multiple Taylor cones without the need of clustering as used in needle emitters and also have a higher Thrust to Power Ratio. A propellant comparison was done considering all the properties required for an ideal propellant for a FEEP system. This comparison led to the selection of indium as working propellant which has an atomic mass of 114.8 u and a melting point of 156.6 °C. The FEEP system was designed keeping in mind easy assembling and modularity of thruster for ease in changing parts. The design consists of three different modules that are assembled separately and then joined together to complete the assembling of the system. The propellant tank, which also houses the emitter, has an internal volume of 32.75 cm3 and can hold approximately 240 grams of indium, which has a density of 7.31 g/cm3. During mission analysis, a 600km altitude orbit was proposed by analyzing the amount of propellant required for drag compensation and de-orbit maneuver at different altitudes with worst case values for ballistic coefficient and Thrust to Weight Ratio. At this altitude, the propellant requirement is 254.4 grams, 14.4 grams more than that of what can fit in the propellant tank of the designed thruster. However, both design of the system and mission analysis are ongoing processes and changes would be made in the future to either one or both to meet the requirements.

  • Fejzo, Orsola
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Proactive Adaptation of Behavior for Smart Connected Objects2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The great amount of generated data from IoT infrastructures in Smart Cities, if properly leveraged, presents the opportunity to shift towards more sustainable practices in rapidly increasing urban areas. Reasoning upon this data in a proactive way, by avoiding unwanted future events before they occur, leads to more efficient services. For a system to do so, a robust reasoning model, able to anticipate upcoming events and pick the most suitable adaptation option is needed. Recently deployed smart waste management systems for monitoring and planning purposes report substantial cost-savings and carbon footprint reductions, however, such systems can be further enhanced by integrating proactive capabilities. This work proposes a novel reasoning model and system architecture called ProAdaWM for more effective and efficient waste operations when faced with severe weather events. A Bayesian Network and Utility Theory, as the basis of Decision Theory, are utilized to model the uncertainties and handle how the system adapts; the proposed model utilizes weather information and data from bin level sensor for reasoning. The approach is validated through the implementation of a prototype and the conduction of a case study; the results demonstrate the expected behavior.

  • Pham, Thi An
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science. PERCCOM.
    Improving the Effectiveness of Building Automation by adaption to the Users Context2019Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    The operations of either residential housing or commercial buildings are energy intensive, estimated to occupy around 40% of all energy consumed worldwide by the year 2030 (by GeSI, SMARTer2030). ICT-enabled smart home or building solutions are expected to contribute to sustainability gain in term of improving energy and resource efficiency. These technologies not only enable buildings to be automated and centrally controlled but also help to provide a healthier and more comfortable living or working environment. While studies in smart home system show good results in reducing the energy consumption of a building by automating tasks to tear down unused appliances, most of the applications are limited implemented based on fixed schedule reassembling user behavior or routines, which is one of the major obstacles for home automation systems (HAS) to be widely acquired. As a solution for this matter, this study aims at exploring actual contexts of user for HAS to adapt in a more meaningful way so that not only the goal of reduced energy consumption is improved, but the user comfort is also taken care of in the best way. Using available studies on the expected reaction in HAS (in this work we focus on German Use case), a rule-based dictionary will be defined as a set of meaningful adaptions which can later be implemented on top of a home automation platform. Then, the study will present the assessment of this model in comparison with available studies to prove an improvement for energy efficiency.

  • Szabo, Florian Akos
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Modelling of secure communication system for IoT enabled waste management system2019Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Urban expansion is a key driving force of our modern world. Increasing environmental footprint is an example issue that is directly caused by it. The city of St. Petersburg employs on average almost 500 garbage trucks on a daily basis and spends more than 1 million US Dollars every year to collect, process and manage waste. In order for megacities, such as St. Petersburg, to cope with its effects, new ideas are needed. This seems to be an obvious area in which technology can be used to improve current practices and help save resources. In this study, we investigate how the Internet of Things, blockchain and Quantum Key Distribution systems can be integrated to provide a safe and efficient method for improving the waste management process in the context of Smart City projects. Our implemented simulations in Mininet show that there are some clear challenges with regards to the adoption of blockchain technology in an IoT environment. However, the integration of quantum channels and the use of Quantum Key Distribution within the blockchain infrastructure shows good potential for balancing the advantages and disadvantages of blockchain. With the implemented simulations we demonstrate the superior capabilities of the Proof of Infrastructure blockchain solution, which can facilitate secure transactions within the waste management scenario.

  • Björck, Sarah
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    The Influence of CSR: How Consumers are Affected by Food Company’s Work with CSR2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Corporate Social Responsibility has grown in importance of the present society and therefore becomes a meaningful operation for companies today. Since the society is structured by consumers, companies have been forced to adapt this concept in their work, by the reason of keeping and gaining the consumers. For companies to be able to do so, they have to understand their customers and be aware of the different consumers purchase intention. These intention have shown to differ in regard of different industries, which is why this study have chosen to focus on the food industry, where the criticisms for the CSR initiatives are high. Consequently, the purpose of the study is to describe how consumers’ in the food industry perceive CSR and to explore how the perceived CSR affects their purchasing intention. Two research questions were made and to be able to answer these, relevant theories was established. The research was conducted using a quantitative study and a descriptive approach to analyze the collected data. The collection of data was made through nine interviews, divided into three involvement level for the reason of including all kinds of consumers. The results found that the general brand appearance is reflected in the companies’ products and therefore made their purchase based on this. The consumers perceived it hard to gain credible knowledge of companies CSR which leads them to make their purchase based on responsible certified labelling or recognition of the products instead. The consumers have a higher credibility for the negative information about companies. They therefore acts with CSR as a purchase criterion of this as they exclude products from this kind of companies. The consumer did however not act with CSR as a purchase criterion if the price was too high, as this was of a greater importance than CSR for the consumers. Because of the low information level and the low credibility, the consumers rather makes their decision based on what they perceive as less irresponsible instead of what they perceive as responsible. Keywords: CSR, Corporate Social Responsibility, Consumer perception, Consumer awareness, Consumer values, Consumer attitudes, CSR purchase criterion

  • Tolvtin, Alfred
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Porous C@TiO2 nanomaterials for efficient wastewater treatment2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Rhodamine B (RB) as a fluorescent dye has toxic effects in the environment, humanity and potentially harmful to ecological systems, therefore it needs to be removed. Adsorption is a simple and cost friendly approach, but the adsorption capacity of the reported adsorbents needs to improve.

    Herein, the preparations of C@titania core-shell nanoparticles for the efficient elimination of RB from simulated textile wastewater was studied. The nanoparticles were prepared by first coating a layer of titania gel on ZIF-8 and HKUST-1 nanoparticles via hydrolysis of Titanium butoxide (TBOT) and followed by carbonization. XRD, FTIR, SEM, TEM, and N2 adsorption-desorption analysis was used to explore the obtained products. The adsorption for RB in the simulated textile wastewater with different pH was investigated.

    TEM pictures visibly illustrate the core-shell structures with a thickness of the titania layer of 14 to 25 nm. N2 adsorption-desorption results display the textural characteristics of the products with mainly meso-pores and a relative high surface area of 107 and 43 m2 g-1 for C@titania core-shell prepared from ZIF-8 and HKUST respectively. The equilibrium adsorption capacities have its climax at pH 7. The maximum RB adsorption capacities of the C@titania core-shell nanoparticles prepared from ZIF-8 and HKUST are 174.4 and 106.3 mg g-1, which is higher than the parental carbons.

    The C@titania nanoparticles can be easily made and their RB adsorption capacities is relatively high. The results show that the C@titania nanoparticles are potential candidates for elimination of RB from water.

  • Torikka, Niklas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    3D Modelling of TEM Data: from Rajapalot Gold-Cobalt prospect, northern Finland2019Independent thesis Advanced level (professional degree), 300 HE creditsStudent thesis
    Abstract [en]

    The Rajapalot gold-cobalt project in northern Finland is an exciting, relatively new discovery, still being explored with hopes to start mining in the future. The area was found by a IP/Resistivity survey in 2013. Extensive geophysical follow-up surveys have delineated several electromagnetic targets, one of which, named Raja, is the target anomaly this master thesis is built upon. A TEM survey was carried out during late August to early September 2018. The data collected was analyzed, processed and later modelled in Maxwell using Leroi, a CSIRO module. Three separate models are produced with one, two, and three plates respectively. The result is compared to existing VTEM and resistivity models.

  • Perdomo, José
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    UE Performance in a 5G Multi-connectivity UDN City Scenario2019Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Multi-connectivity and network densification are two solutions intended to enhance user throughput and reliability. These solutions are critical since 5G NR uses a wide range of frequency bands, which exhibit different varying radio coverage characteristics. This work studies the user equipment (UE) performance using multi-connectivity within an ultra-dense network (UDN) deployed in an urban city environment. By being connected to more than one access node simultaneously, the UE should benefit from increased reliability and data rates at the expense of a potentially increased power consumption. In this letter, we have constructed an urban city environment and a context-aware UE power consumption model. The performance of the UE is assessed with an uplink power control scheme for multi-connectivity and a novel multi-connectivity scheme is proposed. Our simulation results show that dual-connectivity increases performance by up to 44% and 27% in average downlink and uplink throughput, respectively. Similarly, tri-connectivity does the same by up to 45% and 25%. At mid load (forty-five users), the average increase in UE power consumption compared to single-connectivity is 25% and 60% for dual-connectivity and tri-connectivity, respectively. Dual-connectivity increases global UE energy efficiency by up to 30%. Within an urban environment, dual-connectivity decreases the RLF rate by 20% compared to single-connectivity for high speed users.

  • Andersson, Claes
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Predictive Model for Traffic Control in Underground Mines2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Due to the nature of tunnels, a driver in an underground mine may find themselves driving without much vision of the road up ahead. The tunnels usually allow for traffic in both directions but are often only wide enough for a single vehicle. To let vehicles pass each other meeting slots have been carved into the tunnel walls, where one can park while the other passes. Because of the limited vision, however, it is unlikely that a meeting with another vehicle will occur directly next to such a meeting slot. Instead, one of the vehicles must reverse to the closest meeting slot in order to let the other pass. This makes mine tunnels a very inhospitable driving environment, causing disruptions to traffic flow throughout the mine. Unfortunately, typical traffic management or scheduling solutions are not useful, as real-time positioning for the vehicles is often poor while network connectivity cannot be guaranteed in the mine environment.

    This thesis presents a solution which will avoid situations where a driver needs to back up, and instead present meeting slots in which to park ahead of time. This is done by calculating velocity probability distributions for road segments from historical data and using these to estimate arrival times to meeting slots. In addition, a more comprehensive solution is presented, taking into account the accuracy of positioning, outdated information due to poor connections and more complicated scenarios.

    The results show that estimating arrival times using only historical data is a very feasible technology, which can realistically be implemented today. Such an implementation could, in the author's opinion, improve driver safety and efficiency significantly, compared to a driver having no information or simply knowing rough positions of nearby vehicles. This being said, there are still steps that can be taken to improve the solution and to develop a more comprehensive system overall.

  • Sandlund, David
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Wintercorn, Oskar
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Evaluations of Vibrations in a Wet Clutch2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    BorgWarner Powerdrive Systems is constantly developing the performance of wet clutches used in passenger car all-wheel drive systems. The Haldex limited slip coupling, LSC, is the trade name of the all-wheel drive system sold and developed by BorgWarner Powerdrive Systems. In a primary front-wheel driven vehicle, the Haldex LSC can transfer torque to the rear axle based on sensor input with full electronic control and can thus work seamlessly together with other systems such as traction and stability control. In the design of such an all-wheel drive system; it is critical to avoid issues with drive line vibrations as well as the accompanying noise generation. This is a complex issue and even though the goal is to avoid these problems, they may still occur to a certain degree.

    BorgWarner now wants to investigate whether changes in the friction disc quality may affect the occurrence of vibrations. The friction disc quality could e.g. be described in terms of variations in height, material composition, material porosity and Young's modulus with the variations distributed around the circumferential of the friction disc. This study is however limited to investigate if a difference in height could be the cause of drive line vibrations. The goal is to determine if there is a correlation between a shifting thickness around the circumferential of the friction disc and the occurrence of vibrations.

    With the help from RISE Sicomp and their 3D-scanner it was possible to determine the difference in height around the circumference of the disc. The discs was scanned and then analyzed with the help of GOM-software. When the height was measured around the disc they were exposed to a run-in, this with the use of an LSC test rig. This way it is possible to see how the friction characteristics changes while it is being used and to later see if the height difference has changed. All this to see the correlation between the difference in height around the disc and the friction characteristics. A micro tomography scanner at LTU was used to section through the disc. It uses x-ray and makes it possible to look at sections all through the disc to see if there is a difference in the strucure of certain areas. If one pillow is more porous then another one.

    Based solely on the tomography test it is hard explaining the difference in Young’s modulus, the result showed little to none difference between different areas of the disc. With the help from 3D-scanning it has been shown that there is in fact a height difference. That difference becomes smaller with time when used, this due to the wearing of the highest area being greater than that of a lower area. The run-in seems to always have a positive result on the disc. Friction measurements during run-in showed that also a disc with small differences in height could display unfavorable friction characteristics. This would imply that the height difference matters but is not the only contributing factor to vibrations.

    Even though the difference in thickness of the friction disc has shown to contribute to vibrations, there are still factors that remains unclear. If the height would have been the only factor the friction measurements would support this more than what the actual case is. The other factors need further examination.

  • Gan, Princess Rochelle
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Flotation of Yxsjöberg historical tungsten ore tailings2019Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Tailings dams, due to their sheer size and metal content, pose safety and environmental hazards. The Småltjarnen repository, which hosts material from the largest known tungsten mineralization in Sweden named the Yxsjöberg deposit, is estimated to contain 2.2 million tons of material from previous operations when recovery rates of scheelite, chalcopyrite, and fluorite were low. The repository is also observed to contain at least four of the listed critical raw materials by the European Commission in 2017, namely tungsten, fluorite, beryllium, and bismuth. The amenability of this tailings repository as secondary sources for valuable minerals and metals supports the Raw Material Initiative and the drive of the European Union towards a more circular economy. This masters thesis is part of the REMinE (Improve Resource Efficiency and Minimize Environmental Footprint) project that aims to evaluate the amenability of historical mining waste for re-processing from the technical, economical, and environmental perspectives. The study focuses on work package 3 of the project: Identification of new processing methods for mine waste. Previous work on this repository includes geochemical characterization and physical separation through magnetic and gravity separation tests. Since scheelite, the main mineral of the deposit, is commonly recovered through combinations of gravity separation and flotation methods, it is imperative to investigate the response of the material to flotation tests. Further characterization work and flotation tests were rendered on samples from sampling location 6 (60°02'33.6"N 14°46'30.8"E). Previous work was done on samples from and near sampling location 1, which is southwest from location 6. Characterization methods performed on the material included elemental analysis through ICP-SFMS, X-ray diffraction measurements, and mineral liberation analysis as well as physical characterization through particle size distribution analysis and determination of specific gravity. Based on MLA, the material from the main samples showed good liberation by free surface which is important for flotation processes. Mineral association also showed low percentages between scheelite and other Ca-bearing minerals which is a main concern for scheelite flotation. Comparison of characterization work between the two sampling locations allows information on the repository at a larger scope. The common scheelite flotation collector sodium oleate, as well as novel formulations Atrac 2600 and Berol 8313 from Nouryon were tested in combination with the depressant sodium silicate. Based on mass recovery, grade and recovery, selectivity, required dosage, and the degree to which it is environmentally safe, Atrac 2600 at 400 g/t is deemed to produce the most positive results. Based on characterization of the material and flotation tests, an estimated 222,200 tons of -75 µm can go directly into the flotation circuit with an average grade of 0.2768% WO3 and 0.195% Cu. Approximately 15,000 tons at 0.50% WO3 and 14,000 tons at 0.224% Cu can be recovered at a single flotation. Rough mass balance of the process flowsheet indicates a Cu concentrate at 30% Cu will produce 880.50 tons, while a saleable scheelite concentrate at 65% WO3 will yield 672.16 tons from only the original -75 µm fraction of the material. Including the gravity separation tails intended to join the flotation circuit after grinding, an estimated 1,205.54 tons of scheelite at 65% WO3 and 1.860.20 tons of 30% Cu concentrate can be produced. Aside from this, the gravity separation circuit will still be able to yield 188,000 tons of 0.92% WO3 concentrate, which can be further studied if it can be beneficiated to a saleable product. Value estimation of the products for the recommended flowsheet indicate a total of US$ 17 million for the WO3 and Cu concentrates to be produced from the readily amenable -75 µm fraction to be treated directly by flotation. Inclusion of the gravity separation tails mass into the flotation feed yields a value estimated at US$32 million.

  • Burström, Karin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Metal Oxide Composites with Carbon Materials: Synthesis, Characterisation and Preliminary Catalytic Applications2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Nanoparticles combining metal oxides TiO2 and graphene derivatives (reduced graphene oxide and multi-walled carbon nanotubes) were synthesised via wet chemistry methods. The materials were investigated through a series of techniques (scanning electron microscopy, X-ray diffraction, photoluminescence and UV-visible spectrophotometry). The electronic features of the materials were examined by cyclic voltammetry, and some photocatalysis testing was performed, using a solar light simulator and Rhodamine B as a pollutant in water. It was found that addition of the graphene derivative enhanced the electrical properties of the substance, which theoretically should reflect positively in the photocatalytic skill. However, photocatalysis was not found more efficient with the composites, compared to the pristine materials.

    Further, SnO2@ZnO core@shell nanoparticles were synthesised by wet chemistry methods. These materials were investigated by the mentioned methods and preliminary photocatalysis testing was executed, where the composites were found functional, although further testing is required.

  • Kabir, Sami
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    BRB based Deep Learning Approach with Application in Sensor Data Streams2019Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Predicting events based on available data is an effective way to protect human lives. Issuing health alert based on prediction of environmental pollution, executing timely evacuation of people from vulnerable areas based on prediction of natural disasters are the application areas of sensor data stream where accurate and timely prediction is crucial to safeguard people and assets. Thus, prediction accuracy plays a significant role to take precautionary measures and minimize the extent of damage. Belief rule-based Expert System (BRBES) is a rule-driven approach to perform accurate prediction based on knowledge base and inference engine. It outperforms other such knowledge-driven approaches, such as, fuzzy logic, Bayesian probability theory in terms of dealing with uncertainties. On the other hand, Deep Learning is a data-driven approach which belongs to Artificial Intelligence (AI) domain. Deep Learning discovers hidden data pattern by performing analytics on huge amount of data. Thus, Deep Learning is also an effective way to predict events based on available data, such as, historical data and sensor data streams. Integration of Deep Learning with BRBES can improve prediction accuracy further as one can address the inefficiency of the other to bring down error gap. We have taken air pollution prediction as the application area of our proposed integrated approach. Our combined approach has shown higher accuracy than relying only on BRBES and only on Deep Learning.

  • Kanwar, Sofia
    Luleå University of Technology, Department of Arts, Communication and Education, Education, Language, and Teaching.
    Matematikbokens vikt i undervisningen: The importance of the mathematics book in teaching2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    How do teachers use the mathematic textbook in teaching today? Is the mathematic textbook dominant in teaching or is it used as a tool, a so-called artefact? The purpose is to examine the importance of mathematical textbook in today´s teaching in grade three, through a qualitative method. The study two research questions are examined by observations and semi-structured interviews with three different respondents and schools. The data collection is analyzed with phenomenografic research approach.

    All teachers that participated in the study claim that the mathematic textbook is fundamental in the teaching and that the textbook is used to eighty percent in teaching. The teachers assert that there is very little time and that the mathematic textbook facilitates time. The results that emerged from the study are that the mathematic book dominates the teaching. Pupils generally work individually in the mathematics book or with material that is proceed from the mathematic book during the lessons. The conclusion in this study is that there is no major individualization or social interaction in the classroom because of the large proportion of individual work, teachers mostly use materials from the mathematics book or the mathematic book. Finally, both observations and interviews show that the mathematical book dominates teaching in time.

    Large studies such as TIMSS and PISA shows that Nordic countries use the mathematics book more than other countries, and a falling result in mathematics in Sweden. 

    The importance of mathematical textbook in teaching is examined in this study.

     

     

  • Shetty, Pramod
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Study on Supramolecular Gel Lubricants2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Most of the rolling element bearings are lubricated with Grease lubricant. Generally, the grease is expected to serve for life. The major causes of the bearing failure are due to the failure of the lubrication. The grease will experience creeping, oil permeation, oil separation etc. The separated oil will be lost permanently from the bearing. The widely used grease for general application is the lithium grease. The thickener of the grease consists covalent bond. When the grease is sheared, the breakage of the covalent bond will be permanent, resulting in the permanent loss of the rheological properties.

    The gels have unique properties such as thermal reversibility, viscoelasticity and thixotropy. They become mobile under shear stress and solidify again when the shear stress is removed. This property can be harnessed to avoid the base oil creeping, oil permeation, leakage in gears and bearings. Due to the presence of the polar group in the gels, they form a good tribo film and prevent the wear.  Under the shear stress, weak supramolecular interactions will be distorted, and this leads to the release of the oil and they re-form the structure after a certain period of rest. When the gel is in the solid-state, it will avoid creeping and evaporation. Many classes of gels are either derived from natural sources or from environmentally friendly materials. Thus, the lubricant formed out of gel would effectively solve both environmental as well as lubrication problems.

    In this work, supramolecular gel lubricants were prepared out of fully green, cellulose derivatives and starch hydrolysates. The non-ionic hydroxyethyl cellulose (HEC) and anionic sodium carboxymethyl cellulose (NaCMC) were chosen to understand the effect of ionic and non-ionic gelators on the rheological and the tribological parameters. Traditionally fat was used as a lubricant, now, in food industry various fat replacers are being used. To study whether the fat replacers can act as a thickener, Dextrin and maltodextrins were chosen.  Dextrin and maltodextrin with the different DE values were selected to understand the influence of molecular weight on gelation and tribological performance.  Inspired by the recent developments and advantages of aqueous lubrication, mixer of water and poly(ethylene glycol) 200 (PEG 200) is chosen as the base fluid. It was found that a very small amount of gelator can increase the viscosity of the PEG/water to several orders. The thermal stability of the gels was studied using thermogravimetric analysis (TGA) and found that gels can increase the thermal stability of the base fluid. FTIR results showed the formation of a non-covalent bond between the PEG molecules and water. It is shown that anionic gelator will result in producing low friction and wear in comparison to non-ionic gelator. The possible tribo-film formation due to the negative charge in the NaCMC molecules is attributed to these results. The very low friction and low wear was exhibited by the dextrin and maltodextrin gels. It is proposed that this could be due to the microspherical particles of gels which can act as nano bearings. It was found that choosing the optimum concentration of the gelator is important to reduce friction and wear. The higher gelator concentration will form the hard gel, which cannot flow and replenish the sliding contact, resulting in the starved lubrication. This will cause high wear and friction. These gel lubricants can be used in food, pharmaceutical and biomedical industries.

  • Wallenberg, Axel
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Frosteman, Alexander
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    An ICE concept optimized for Series Hybrid Application: A dive into how an ICE pairs with a Series hybrid drivetrain2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report is a theoretical study of the potential an ICE (internal combustion engine) has when combined with the load case of a high-performance series hybrid drivetrain. It breaks down the different theoretical variables that affect engine efficiency and possible limitations that arise. The report then moves on to specifying the current emerging technologies associated with increasing engine efficiency such as active, and passive prechamber ignition. The different technologies strengths and weaknesses were then compared with each other to decide the best strategies and technologies to move forward with. Here efficiency gain potential was compared to price, performance and complexity. The different technologies were compared in two separate steps firstly the technologies were compared individually, then the best systems were compared to different engine configurations in an iterative process. Here the most balanced solution was found using a passive prechamber to allow higher compression ratio while allowing better timing control. This was later combined with a Miller cycle strategy resulting in a theoretical efficiency improvement of ~8%. This would potentially allow a high performance vehicle to match a midrange diesel engine in fuel economy.

  • Garskaite, Edita
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Karlsson, Olov
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Stankeviciute, Zivile
    Institute of Chemistry, Faculty of Chemistry and Geosciences, Vilnius University, Vilnius, Lithuania.
    Aivaras, Kareiva
    Institute of Chemistry, Faculty of Chemistry and Geosciences, Vilnius University, Vilnius, Lithuania.
    Jones, Dennis
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Sandberg, Dick
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Surface hardness and flammability of Na2SiO3 andnano-TiO2 reinforced wood composites2019In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, no 48, p. 27973-27986Article in journal (Refereed)
    Abstract [en]

    The objective of this study was to explore an effect of the combined inorganic materials on the wood hardness and flame-retardancy properties in a concept of sustainable material management. Herein, the reinforcement of Scots pine (Pinus sylvestris L.) sapwood with sodium silicate and TiO2 nanoparticles via vacuum-pressure technique is reported. Pyrolysis of modified wood was studied by TG-FTIR analysis; the results showed that maximum weight loss for the modified wood was obtained at 40–50 °C lower temperatures compared to the reference untreated wood. The Gram–Schmidt profiles and spectra extracted at maxima absorption from Gram–Schmidt plots indicated chemical changes in wood–inorganic composites. SEM/EDS analysis revealed the presence of Na–O–Si solid gel within the wood-cell lumen and showed that TiO2 was homogeneously distributed within the amorphous Na–O–Si glass-forming phase to form a thin surface coating. EDS mapping further revealed the higher diffusivity of sodium into the cell wall compared to the silicon compound. The presence of amorphous sodium silicate and nano-TiO2 was additionally confirmed by XRD analysis. FTIR spectra confirmed the chemical changes in Scots pine sapwood induced by alkalization. Brinell hardness test showed that the hardness of the modified wood increased with the highest value (44% increase in hardness) obtained for 10% Na2SiO3–nTiO2 modified wood. The results showed good correlation between TG and flammability test; limiting oxygen index (LOI) values for the wood–inorganic composites increased by 9–14% compared to the untreated wood.

  • Dittes, Nicholas J.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Bearing with condition monitoring sensor2018Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    A bearing arrangement is disclosed. The bearing arrangement includes a bearing with a bearing lubricant. A first electrically conductive portion and a second electrically conductive portion, which have different electronegativities, are in direct contact with the bearing lubricant. The bearing lubricant and the first and second electrically conductive portions form an electrolyte and two electrodes, respectively, of an electrochemical cell. The bearing arrangement further includes a sensor connected to the first electrically conductive portion and to the second electrically conductive portion, the sensor being configured to measure at least one of a current and a galvanic potential between the first and second electrically conductive portions and to determine a water content in the bearing lubricant based on the measurement.

  • Hafeez, Abdul
    et al.
    Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Akhter, Zareen
    Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan.
    Gallagher, John F.
    School of Chemical Sciences, Dublin City University, Glasnevin, Dublin, Ireland.
    Khan, Nawazish Ali
    Materials Science Laboratory, Department of Physics, Quaid-i-Azam University, Islamabad, Pakistan.
    Gul, Asghari
    Department of Chemistry, COMSATS University, Islamabad, Pakistan.
    Shah, Faiz Ullah
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Synthesis, Crystal Structures, and Spectroscopic Characterization of Bis-aldehyde Monomers and Their Electrically Conductive Pristine Polyazomethines2019In: Polymers, ISSN 2073-4360, E-ISSN 2073-4360, Vol. 11, no 9, article id 1498Article in journal (Refereed)
    Abstract [en]

    Bis-aldehyde monomers 4-(4′-formyl-phenoxy)benzaldehyde (3a), 3-methoxy-4-(4′-formyl-phenoxy)benzaldehyde (3b), and 3-ethoxy-4-(4′-formyl-phenoxy)benzaldehyde (3c) were synthesized by etherification of 4-fluorobenzaldehyde (1) with 4-hydroxybenzaldehyde (2a), 3-methoxy-4-hydroxybenzaldehyde (2b), and 3-ethoxy-4-hydroxybenzaldehyde (2c), respectively. Each monomer was polymerized with p-phenylenediamine and 4,4′-diaminodiphenyl ether to yield six poly(azomethine)s. Single crystal X-ray diffraction structures of 3b and 3c were determined. The structural characterization of the monomers and poly(azomethine)s was performed by FT-IR and NMR spectroscopic techniques and elemental analysis. Physicochemical properties of polymers were investigated by powder X-ray diffraction, thermogravimetric analysis (TGA), viscometry, UV–vis, spectroscopy and photoluminescence. These polymers were subjected to electrical conductivity measurements by the four-probe method, and their conductivities were found to be in the range 4.0 × 10−5 to 6.4 × 10−5 Scm−1, which was significantly higher than the values reported so far.

  • Schweiger, Gerald
    et al.
    Graz University of Technology, Austria.
    Nilsson, Henrik
    University of Nottingham, UK.
    Schöggl, Josef Peter
    KTH, Royal Institute of Technology, Sweden.
    Birk, Wolfgang
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Posch, Alfred
    University of Graz, Austria.
    Modeling and simulation of large-scale systems: A systematic comparison of modeling paradigms2020In: Applied Mathematics and Computation, ISSN 0096-3003, E-ISSN 1873-5649, Vol. 365, article id 124713Article, review/survey (Refereed)
    Abstract [en]

    A trend across most areas where simulation-driven development is used is the ever in- creasing size and complexity of the systems under consideration, pushing established methods of modeling and simulation towards their limits. This paper complements existing surveys on large-scale modeling and simulation of physical systems by conducting expert surveys. We conducted a two-stage empirical survey in order to investigate research needs, current challenges as well as promising modeling and simulation paradigms. Furthermore, we applied the analytic hierarchy process method to prioritise the strengths and weak- ness of different modeling paradigms. The results of this study show that experts consider acausal modeling techniques to be suitable for modeling large scale systems, while causal techniques are considered less suitable.

  • Edin, Emil
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Characterization of Heat Treated LMwD Ti-6Al-4V to Study the Effect of Cooling Rate on Microstructure and Mechanical Properties2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this work, the influence of different cooling rates (5, 20, 50 and 100 °C/s) on the microstructure and mechanical properties of Laser Metal Wire Deposited (LMwD) Ti-6Al-4V was investigated, this was done using a thermal-mechanical physical simulation system (Gleeble 3800, DSI). Two different soak times above β transus (held at 1100 °C), 5 and 40 s, were used and after cooling to 150 °C, the samples were tensile tested. The samples were characterized with optical microscopy (OM) and scanning electron microscopy (SEM) and hardness testing. The results were then compared, both with each other and with two reference samples, that were only heated to 150 °C and then tensile tested. It was found that for the lowest cooling rate, 5 °C/s, the microstructure had transformed from a basketweave α microstructure to a colony α microstructure in the center of the specimen waist where heating was most efficient. Ultimate tensile strength (UTS) was found to be in the range of 858 – 977 MPa, with the highest average being recorded for the reference samples, similar results were noted for the strain, with a range of  ⁓5 – 14 %, where the highest recorded average was for the reference samples. However, the extensometer used was not optimized for this kind of test, therefore percent reduction of area (RA) measurements were performed. The RA measurements produced a significantly different result than that obtained from the testing, a large scatter in the ductility was found, possibly due to thermal instability that occurred during testing. Overall, the microstructure appears to be relatively stable over the cooling range of 20 - 100 °C/s, no major differences were observed, the microstructure consisted of a homogeneous basketweave α microstructure, with little to no change in the measured average α lath thickness.

  • Joakim, Eck
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Development of systematic measurement on liquid metal2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The most common way of producing steel worldwide is with the continuous casting process, where a strand of steel is continuously cast. Further optimization of this process requires data from measurements, measurements which must take place in a hostile high-temperature and corrosive environment such as liquid steel.

    At Swerim, a Continuous Casting Simulator has been constructed to replicate the flow conditions in the process. A eutectic bismuth-tin alloy with properties similar to steel is used instead to make measurements in liquid metal possible. In this report pressure, velocity and vibration measurements were made using multiple sensors under different flow conditions.

  • Sundström, Emil
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Shared Augmented Reality: Developing a Multiplayer AR Mobile Game to Study Playability2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this study has been to investigate if the Pervasive GameFlow Model is suitable for evaluating Player Experience in Augmented Reality games. The work has described a definition of Augmented Reality, how it generally operates and reviewed common challenges when developing Augmented Reality applications. A prototype game has been developed, based on a previous concept of merging board games with computer games using Augmented Reality. After development, the game has been tested with a method based on the Pervasive GameFlow Model. Results showed the model to be suitable for future tests and evaluations, but did not produce data for evolving the game design. Generating such data would require execution of additional testing methods.

  • Ehlin, Max
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    An overview of Product Service System through Integrated Vehicle Health Management in an information sensitive industry2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Purpose – The research purpose is to enhance knowledge of how organizations can form a PSS through an IVHM system when information is sensitive.

    Method – A single case study design of abductive approach was used, with data collection through six semi-structured interviews.

    Findings – A system combining IVHM and PSS has many potential benefits, however there are several challenges that need to be overcome in order to implementing a successful model.

    Theoretical implications – This study treads a new area not previously explored in the literature when it combines PSS and IVHM, which relies heavily on information flow to succeed, with a case of information sensitivity. This study hence explores a problematic area for either PSS or IVHM, expanding the current literature and providing initial suggestions of how to navigate this.

    Practical implications – Firstly, it shows managers the challenges that comes with implementing PSS-IVHM and increasing involvement in the customers’ processes. Secondly, this study shows the theoretical and general challenges of PSS-IVHM and applies the case study’s perspective of information management, granting managers a larger foundation of knowledge before starting their initiatives of PSS-IVHM.

    Limitations and future research – This study provides a limited amount of empirical data. Therefore, future research should focus on increasing and widening data collection. The study suggests there is a considerable challenge in conservatism within the defence industry and therefore future research is suggested to explore how change management can combat this challenge.

  • Paavola, Elin
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Paavola, Sarah
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Utmaningar vid försäljning av funktionella produkter: En studie utifrån ett redovisningsperspektiv2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Sales of functional products include both goods and services. The concept of functional products contains many different components and is sold over long contracts, which means that today’s regulations for accounting do not provide sufficient guidance. The purpose of this study is to identify and describe the challenges with an accounting perspective in the sale of functional products. The goal is also to create an understanding of how economists use today's rules in complex accounting situations when selling functional products. To be able to answer the purpose, the study has been performed with a qualitative research strategy and a deductive approach. The study has been taken from an actor's approach to create an understanding of how the individual perceives the challenges surrounding the sale of functional products. Since functional products are a concept that is not well known, interviews with three economists have been conducted. A scenario that described the concept of functional products was presented to the economists before the interviews so that respondents would have the same starting point for the interviews. During the interviews, the respondents told us how they interpreted and assessed the situation described in the scenario. With support in previous research, the establishment of contracts, comparability with regard to risk management, accounting rules with a background in product pricing and complex accounting situations have been identified as challenges in the sale of functional products. f A complex challenge is that the contracts extend over 20 to 30 years. A frame of references has been developed which has formed the basis for an analysis of the interviews. The results of the study show that the economist's basic work should include assessments that require a high level of expertise in order to reflect reality. The accounting of functional products places high demands on the economist's knowledge and assessments. The accounting of a functional product cannot be generalised because each functional product is specifically designed for the needs of a particular customer. This means that it will be more difficult to meet the comparability requirement when companies start to sell more complex products, which is expected to contribute to the development of new regulatory frameworks over time. A probable solution is that economists, just as when economists today apply the acquis IFRS 15, will develop their own standards of recognition to meet the qualitative characteristics. Based on this study, we believe that further research into the reporting of functional products is important in terms of the differences between short and long contracts and how sales differ between companies.

  • Tiu, Glacialle
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Sulfide chemistry and trace element deportment at the metamorphosed Lappberget Zn-Pb-Ag-(Cu-Au) ore body, Sweden: Implications for Mineral Processing2019In: Life with Ore Deposits on Earth: Proceedings of the 15th SGA Biennial Meeting 2019, Glasgow, Scotland, 2019, Vol. 4, p. 1486-1489Conference paper (Refereed)
    Abstract [en]

    The 58 Mt Lappberget Zn-Pb-Ag-(Cu-Au) ore body represents one of the largest and most significant polymetallic base metal sulfide deposits in Sweden. The complex mineralogical characteristics of the ore body pose particularly tough challenges for successful production forecast because of the mixed Zn-Pb-Cu base metals, the complex association of the beneficial Ag and Au, and the presence of influential elements such as Sb, Mn and Mg. Thus, a detailed mineralogical characterization study was conducted, focusing on the deportment of trace and minor elements (including credit and penalty elements). Mineral chemistry data derived from electron microprobe and   laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses reveal the complexity in the composition and associations of the ore minerals, consisting of textural and chemical varieties of sphalerite, galena, chalcopyrite, iron sulfides, antimonides and sulfosalts. Recrystallization, re-mobilization and re-concentration of sulfide minerals, compositional banding, and ductile and brittle deformation textures (i.e. deformation twins on sphalerite, brecciation, bent cleavage planes, etc.) are observed throughout the deposit. The mineralogical and textural complexity and heterogeneity of the sulfide ore are reflected in the variability in grades and recovery from the processing plant.

  • Kullberg, Angelika
    et al.
    Department of Pedagogical, Curricular and Professional Studies, University of Gothenburg, Gothenburg, Sweden.
    Vikström, Anna
    Luleå University of Technology, Department of Arts, Communication and Education, Education, Language, and Teaching.
    Runesson, Ulla
    School of Education and Communication, University of Jönköping, Jönköping, Sweden.
    Mechanisms enabling knowledge production in learning study2019In: International Journal for Lesson and Learning Studies, ISSN 2046-8253, E-ISSN 2046-8261Article in journal (Refereed)
    Abstract [en]

    Purpose – The purpose of this paper is to add to the discussion about practitioner research in schools – by addressing mechanisms and systematic strategies based on theory in a research model, which enables the creation of knowledge products that enhance student learning and are sharable between teachers.

    Design/methodology/approach – The research question is the following: Can a specific form of teachers’ research produce practice-based knowledge relevant beyond the borders of the local school context? This question is addressed through empirical examples from previously published papers on learning studies in natural sciences, mathematics and language.

    Findings – This paper promotes the view that teachers in learning studies can create practical public knowledge relevant beyond their local context. The authors suggest that learning studies and variation theory can offer teachers mechanisms to create such public knowledge.

    Originality/value – The paper proposes that teachers’ collaboration in professional learning communities,  as in a learning study, not only has the capacity to increase students’ and teachers’ learning, but it can also be used to create practical public knowledge.

    Keywords Learning study, Variation theory, Professional learning communities, Mathematics

    Paper type Conceptual paper

  • Bagiaras, Gabriella
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    "Tyst nu boys det osar så jävla mycket testo här inne": En sociologisk studie om traditionella genusmönsters påverkan på flickors och pojkars utbildning2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna studie undersöker traditionella genusmönsters påverkan på flickors och pojkars utbildning.

    Studien har utförts genom observationer och intervjuer på en gymnasieskola i Luleå i syfte att undersöka om traditionella genusmönster påverkar flickors och pojkars utbildning, om förekomst av traditionella genusmönster kan begränsa flickor och pojkar från att tillgodogöra sig undervisning samt hur lärarens agerande kan påverka beteenden i klassrumssituationen som baseras på traditionella genusmönster. Studien omfattar även ett teoretiskt ramverk som beskriver genus, genusregimer och hur en könsidentitet utformas.

    Resultatet av studien visar att de fasta genusarrangemang som finns i samhället påverkar möjligheten till lika utbildning oavsett kön. Flickor och pojkar agerar enligt traditionella genusmönster och tilldelade könsidentiteter vilket i många sammanhang påverkar möjligheten till inlärning för respektive kön. Den sociologiska problemställningen visar att pojkar genom sin uppfattning om maskulinitet begränsar sig själv från möjlighet till inlärning. Samtidigt anpassar sig flickor till den traditionella bild som finns av den kvinnliga könsidentiteten och där igenom begränsar de sig från att ta den plats de skulle önska ta. Genom sitt agerande kan en lärare förstärka eller förhindra beteenden baserade på traditionella genusmönster. Studien visar att lärare har en ambition att bedriva undervisning med utgångspunkt från individ i stället för kön. De fasta genusarrangemang som finns i samhället och som påverkar flickor och pojkars beteende kan dock göra det svårt för en lärare att agera på ett sätt som tonar ner i stället för lyfter fram traditionella genusmönster.

  • Bergström, Linda
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Information, delaktighet och tid: En kvalitativ studie av ledarskapets villkor vid förändring och omställning2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The specific conditions of health care entail three important factors that leadership must handle; to lead in complexity, lead other leaders from different professions and lead to and for change and improvement. Change can lead to anxiety and resistance in workplaces therefore the manager`s role often results in dealing with both concerns and resistance that may arise in the event of change. Leading as a manager in reform work is therefore largely about informing and creating participation. Many problems that have been identified in the public sector in recent years have been linked to an absence of, or deficient leadership. Work imbalances where demands made are not consistent with the resources provided are described as a reality for many managers, especially in caring activities.

    Leadership conditions are influenced by constant changes, that lead to high demands, which require the leader to manage both crisis, chaos and conversion. Hence, the purpose of this study has been to investigate managers' experience of conditions for leadership in the event of reform and readjustments in operations. The research questions in this study have been intended to investigate which responsibility the leader experiences in the event of reform and readjustments, which requirements the leader experiences in the event of reform and readjustments, and what opportunities and obstacles the leader experiences in the event of reform and readjustments in the workplace.  

    The essay has been carried out with a qualitative method as the purpose of the study was to access the participants' own experiences of conditions for leadership in the event of reform. The collection of empirical data has been carried out through both semi-structured interviews of unit managers within health care and participatory observation. Requirements, the support and control model as well as theories of the transformative leadership have served as initial inspiration in the study, and these, together with the theories of change and the conditions of leadership, have been used in the analysis and interpretation of the empirical data. The results indicated that the conditions that leaders must manage, lead and implement changes today are insufficient because important aspects are missing. These are information, participation and time, which are directly linked to the leader's conditions for being able to make changes. The study indicated that the participants themselves create a network with both knowledge, information and experience that can then help them in the recreation of conditions for implementing changes.

  • Ek, Anton
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Silicon surface passivation via ultra-thin SiO2, TiO2, and Al2O3 layers2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Energy traps at the silicon surface originating from discontinuities in the lattice is detrimental to the performance of solar cells. Acting as recombination centers, they offer a location where the charge carriers may easily return to their original energy band after excitation. Surface passivation is an effective method to combat this and can be done either by suppressing traps (lowering trap density) or by forming an electric field, preventing the carriers from reaching the defect states. Silicon oxide, SiO2, and aluminum oxide, Al2O3, are two materials which have previously been shown to provide good passivating qualities. In this thesis, SiO2 and Al2O3 have been used both as single layers and in a stack configuration to passivate the surface of crystalline silicon (c-Si).

    Using a response surface methodology approach, temperature optimization with respect to deposition and annealing temperature has been conducted for SiO2/Al2O3 stacks deposited with plasma-enhanced atomic layer deposition, PEALD. It was shown that the same deposition temperature (Tdeposition = 140 °C, Tanneal = 395 °C) could be used for both materials and provide good passivation with an effective surface recombination velocity, Seff, of 5.3 cm/s (1Ωcm n-type Si wafers). From FTIR measurements, an increase in hydroxyl groups was seen as the SiO2 deposition temperature increased while the opposite was observed for Al2O3 which also showed fewer carbon related impurities with increasing temperature. Increasing the SiO2 temperature strongly affected the fixed charge density, causing it to decrease and even switch polarity. The fixed charge density could also be controlled by varying the thickness of the intermediate SiO2 layer. At a thickness of 1-2 nm, a minimum in the effective lifetime was observed and was correlated to Si close to flat-band conditions. N-type wafers showed a larger negative fixed charge density than p-type wafers which results in stronger field-effect passivation.

    For phosphorous doped emitters (200 Ω/sq on 10 Ωcm p-type wafer), it was seen that SiO2/Al2O3 stacks with a SiNx anti-reflection coating performed better than SiO2 or Al2O3 single layers. By depositing SiO2 at 130 °C in SiO2/Al2O3 stacks and annealing at 450 °C, an implied open circuit voltage (iVoc) of 710 mV was measured (AM1.5G) together with an implied fill factor (iFF) of 84.1% and a recombination parameter (J0) of 19.2 fA/cm2. Al2O3 single layer showed an extremely low J0 of 10 fA/cm2 but suffered from a decreased iFF and strong injection dependent lifetimes which originates from an inversion layer.

    ALD ozone processes were successfully developed for SiO2 and Al2O3.  The deposition rate per cycle for SiO2 was found to be only ~0.175 Ǻ/cycle (PEALD ~1.1 Ǻ/cycle), making it rather unpractical for use outside of research. Single layer SiO2 deposited with ozone showed, similarly to a plasma process, almost no surface passivation. Al2O3 however proved to be highly passivating on its own with a τeff = 3.8 ms, Seff = 1.2 cm/s (1 Ωcm n-type) after depositing at 250 °C. Studies on the effect of annealing showed that an annealing temperature of 450 °C is necessary to completely activate the passivation. The low Seff values were attributed to a very high negative fixed charge density ~1013 cm-2 together with strong chemical passivation.

  • Kinnander, Joakim
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    ”Det ska vara en chef, inte en mespropp!”: En kvalitativ studie om två olika generationers uppfattningar av motiverande ledarskap2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Arbetstagares närmsta chef har en specifik roll som innebär att leda och fördela arbetet men även att vara en förebild och ansvara för vilket klimat som finns inom arbetsgruppen. På arbetsmarknaden återfinns människor från olika generationer, dessa tenderar att uppleva och förstå världen på olika sätt. Detta gör chefens ansvarsroll mer komplex eftersom dennes ledarskap ska motivera människor som förstår världen på olika sätt. Syftet med denna studie är att undersöka två generationer av arbetstagares uppfattningar om vad ett motiverande ledarskap innebär. För att uppfylla syftet används två forskningsfrågor: Vilka uppfattningar har de två generationerna om ledarskapstyperna: Auktoritärt, demokratiskt och låt-gå-ledare? Vilka likheter och skillnader finns mellan de två generationernas uppfattningar kring motiverande ledarskap? Metoden är kvalitativ och det empiriska materialet har samlats in med hjälp av semistrukturerade intervjuer med sammanlagt sex intervjupersoner tillhörande två olika generationer, 1960- och 1990-talister. Det teoretiska ramverk som använts för att analysera det empiriska materialet består av Lennéer Axelson och Thylefors (2005) teori om de tre ledartyperna: auktoritärt, demokratiskt samt låt-gå-ledare och Giddens (2008) självet och självidentitet. Resultatet tyder på att det inte finns någon direkt skillnad mellan de två generationernas uppfattningar om vad ett motiverande ledarskap innebär. Generationerna hade liknande uppfattningar gällande hur en chef ska agera för att dennes ledarskap ska uppfattas som motiverande. Det handlar om att skapa en delaktighet bland medarbetarna där dessa känner sig sedda och bekräftade samt att chefen behöver vara närvarande för att kunna skapa en relation till medarbetarna.

  • Lidén Lindbäck, Mattias
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Butik eller Internet?: En kvantitativ studie om var studenter väljer att handla2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Användandet av internet och e-handel har ökat de senaste åren då butiker idag behöver konkurrera med både andra butiker samt internet. Idag är det allt vanligare att konsumenter handlar sina varor via internet med tanke på utvecklingen och den allt större möjligheten att använda sig av internet vart som helst och när som helst. Studenter använder bland annat e-handeln för att köpa den studentlitteratur de behöver och har även datorer då de utför sina uppgifter, vilket ökar tillgängligheten till e-handeln. I denna studie undersöks vilka faktorer som bidrar till att studenter väljer att handla sina varor via internet istället för i fysiska butiker.

    Resultatet av denna studie bygger på en kvantitativ forskningsmetod där webbenkäter använts för insamling av data riktad till studenter vid Luleå Tekniska Universitet. Faktorer som tillit till återförsäljaren är viktig enligt mängder av forskning och var även viktigt bland studenter då detta minskar känslan att riskera exempelvis sin ekonomi. Samtidigt som återförsäljaren användning av ’cookies’ i marknadssyfte inte bedöms vara ett problem bland studenter då detta inte medförde någon minskning i sökandet efter information. Bland studenterna visade det sig även att faktorer som utbud, bekvämlighet och tidsbesparande var de faktorer som bidrog till största delen av varför e-handel föredras framför handel i butik. Detta då ett ökat utbud ökar möjligheten till att testa sig fram mellan olika stilar och på så sätt framhäva sig själv, samtidigt som studenterna även menar att det är viktigt att återförsäljaren har fria returer och säkerbetalning. Trots dessa faktorer råder det skilda meningar om studenter föredrar att handla över internet eller i butik.

  • Norén, Hanna
    et al.
    Luleå University of Technology, Department of Arts, Communication and Education.
    Sellin Nilsson, Emelia
    Luleå University of Technology, Department of Arts, Communication and Education.
    Genus i förskolan: Barns konstruktion av genus i den fria leken2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet i denna studie var att undersöka hur barn konstruerar genus i den fria leken på förskolan. Studien var av kvalitativ karaktär och utgick från ett socialkonstruktionistiskt perspektiv. Observation av barn i den fria leken var den valda metoden för datainsamling och denna registrerades med hjälp av observationsschema och ljudinspelning. Resultatet visade att barnens konstruktion av genus kom till uttryck i lekrollerna genom barnens olika sätt att använda kropp, röst, uttalanden och handlingar beroende på lekrollernas kön. Dessutom visade resultatet att genus konstruerades på olika sätt i barnens förhandlingar utifrån kläder, hårlängd, sättet att prata, användande av nikotin och vänlighet. Slutsatser vi dragit utifrån diskussionen av resultatet är att genus är föränderligt och att denna förändring sker i social interaktion mellan människor.

  • Näsman, Markus
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Evaluation of alternative methods forquality control of Tungsten Carbide: An evaluation of four different particle measuring techniques2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of this study was to evaluate four different measuring methods as potentialquality control tests for Tungsten Carbide (WC) raw material used in the hard metalmanufacturing at Seco Tools Fagersta. This was warranted as the current quality testcalled the HcK test, is very time consuming and the results provided that are used formilling time calculations cannot be relied on. The four measuring methods chosen wasLaser diffraction, X-Ray diffraction, Brunauer Emmett Teller analysis and Fisher Sub-Sieve Sizer measurement. These measuring techniques were chosen by Seco ToolsThe project followed the general structure of the project cycle modified to fit the projectand involving the steps project planning, present state analysis, goals and requirementdetermination, evaluation elimination of options and final of choice of option. Thealternative methods were evaluated using an evaluation matrix containing therequirements determined to be the most relevant for the quality control process. Therequirements were measurement precision, operator influence, ease of use, time requiredand operator time required. The ability of the measurement method to distinguishbetween all of the different WC powders used a Seco Tools was put as a must requirementas the new method is meant to serve as a verification test as well as a quality test.The analysis methods were evaluated practically through experiments and therefore atesting strategy was established. Initial test on two powder types was performed so thatan early evaluation could be done. During this stage both the Laser diffraction and the XRaydiffraction were eliminated due to poor results. The BET analysis and the Fisher Sub-Sieve Sizer performed better and was therefore tested further. Randomized testing wasthe method chosen when testing with all powders to minimize the environmental impacton the testing as this could affect the results of the study.The testing showed that only the Fisher SSS was able to distinguish between all thedifferent powders making it the only viable option as a new quality test. This was onlypossible when measuring on agglomerated material and the values extracted couldtherefore not be used further in the production. The Fisher SSS also performed the bestwhen ranked against the rest of the requirements, showing a high precision whenmeasuring on deagglomerated material and a combination of the two tests was thereforeconsidered.When compared to the HcK test the Fisher SSS showed a significant reduction in lead timebut also a reduction in information gathered and eventual defects controlled. The FisherSSS provides only an average particle size measurement and since no correlation has yetbeen established between the measured particle size and the required milling times it wasrecommended that the HcK test remains.It was recommended that a study is started aimed at establishing a correlation betweenthe measured particle size and the required milling time is started to investigate if this ispossible.

  • Olofsson, Emelie
    et al.
    Luleå University of Technology, Department of Arts, Communication and Education.
    Hedman, Linda
    Luleå University of Technology, Department of Arts, Communication and Education.
    En förskola för alla?: Specialpedagogik-ett arbetssätt för att skapa en inkluderande förskola2019Independent thesis Basic level (professional degree), 210 HE creditsStudent thesis
    Abstract [sv]

    Syftet med denna studie är att bidra med kunskap om vad förskollärare anser vara viktigt i arbetet med barn i behov av särskilt stöd gällande deras egna förhållningssätt och planeringen av en inkluderande verksamhet. Vi har valt att utgå ifrån ett sociokulturellt perspektiv som fokuserar på lärande i samspel, kommunikation och att barnen är kompetenta individer. Kvalitativa intervjuer med två förskollärare genomfördes och bearbetades i tre steg: sortering, reducering och argumentation. Resultatet blev att förhållningssätt, samverkan, organisation, metoder och reflektion är viktiga aspekter gällande inkluderingen av barn i behov av särskilt stöd i förskolan. Diskussioner gällande vad begreppen inkludering och delaktighet innebär, har förts mellan oss studenter och även med förskollärarna i intervjuerna. De slutsatser som vi kunnat dra är att det specialpedagogiska arbetet är en viktig del av förskolans verksamhet och ska anpassas efter de individer som är i behov av detta arbetssätt. Samtidigt måste förskollärare ha i åtanke att specialpedagogik är ett arbetssätt som gynnar alla barn som vistas i förskolan. Med denna studie hoppas vi kunna belysa hur viktig specialpedagogiken är för en inkluderande förskola.

  • Stenberg, Anna
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Kommunicera mera!: Upplevelser av organisationsförändring ur ett medarbetarperspektiv2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    When a workplace is in a process of change, there are several different factors that influence how employees among the organization react. This study was carried out at an authority that previously had a customer center that received incoming calls from customers but have now distributed the task to the authority's administrators. Thus, the duties of the administrators have changed, and this study therefore aims to examine the employees' experiences of the organizational change. To answer the purpose, three research questions have been enunciated; “how has the organizational change been communicated from management to employees?”, “how have the employees been involved in the change process?” and “what are the positive and negative experiences of the organizational change?”. This study is based on a qualitative method and the empirical material has been collected through eight semi-structured interviews with employees at one of the authority’s units. The theoretical framework has been divided into sub-categories such as communication, employee participation and co-workers attitudes and these has subsequently been constituted by Johansson & Heide (2008) and Angelöw (2010) theories about communication, Angelöw’s (2010) theory about participation, Angelöw’s (2010) theory about co-workers attitudes and Heide, Johansson and Simonsson’s (2012) interpretation of Bupp’s (1996) reaction curve regarding grief. Finally, Kotters (1996) 8-step model regarding change has been applied. The theoretical framework has been supplemented with scientific articles. The empirical data has been analyzed using theory and previous research.

    The study's results show that the experiences have been significantly negative as the employees felt that communication was inadequate. The strongest positive experience was when employees' views were received by management, resulting in a changed work schedule. Result of the study demonstrates that organizations advantageously should communicate the change purpose in order to create a greater understanding among the employees. Organizations should also involve the employees in an early stage in order to maintain a positive experience.

  • Trane, Joakim
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Structural and Fire Engineering.
    En studie i automatiska brandlarmsystem hos Norrbottens läns sjukhus2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Automatic fire alarm systems (AFAS) often play a central role regarding the fire protection in buildings. These systems are important in the sense that they are designed to detect fire at an early stage and activate certain safety systems to minimize the consequences of a fire. An example of this can be to activate the emergency alarm or specific control of the ventilation system. Hospitals are often complex buildings with multiple departments under the same roof, and because of this there are high requirements regarding the function and reliability of the AFAS.

    It is mentioned in Sweden, as well as internationally in Europe, that very few of the registered alarms from AFAS are due to actual fires, as compared to the number of alarms with no fire. It is not unusual that the percentage of actual fires are as low as 5% of all the registered alarms. Fires occurred in the hospitals of Norrbottens län are not only due to accidents and technical errors, but also the malice and desperate actions of individual people. So how does the AFAS in the five hospitals of Norrbottens län work, and what are the local fire departments conceptions of them?

    The AFAS in these hospitals were studied through a pilot study, document review and thereafter a qualitative interview study. The interview study was conducted with technical staff from hospitals, fire departments and inspectors. A primary focus was to determine whether these systems provides an equivalent protection across all the five hospitals or if any of the hospitals stand out in any way. The aim of this work has also been to investigate the opinions of the technical staff at the hospitals as well as the local fire departments. There are comprehensive regulations regarding which types of buildings that require AFAS, how they should be dimensioned, maintained and inspected. SBF 110 – Regler för brandlarm regulates that major inspections shall be performed yearly. The document review consisted of a compilation and comparison of protocols conducted each year at the different hospitals. Incident statistics from the fire departments were also examined.

    The incident reviews and protocols from the yearly inspections for the different hospitals differed. With a closer look, similarities between incident reviews and protocols could be seen. These similarities, along with gathered opinions from the interviews, showed that maintenance and actions taken to faults in the systems differed between the hospitals. Some for the better and some for the worse. The opinions of both the fire departments and the inspectors, independently, strengthen these observations. With these opinions along with theories and results from previous studies, conclusions could be made.

    The inspectors were of the opinion that some hospitals take actions and actively work for a safer and more reliable system, while others were perceived as if they are not as willing to make improvements. The fire departments also differed in their opinions. One said that the hospital is very large and not a major problem regarding alarms, but that a certain amount of alarms must be anticipated and accepted due to the large operation of a hospital. Another fire department said that their hospital is one of the largest contributors of the automatic fire alarms

    Abstract

    IV

    in the region and hope for an improvement. The technical staff in the hospitals were generally pleased with their systems and didn’t experience any major problems.

    By an overall assessment Gällivare hospital is considered to be the hospital that has the most amount of work to be done in order to be on the same level as the better performing hospitals. Contributing factors to this conclusion was the, by comparison, relatively high false alarm- statistics and low rate of actions taken to faults. The opinions of the inspectors did, as a third impartial part, serve as a good complement and reflected these observations. Kalix, Kiruna and Piteå were the hospitals with the least amount of perceived flaws. This conclusion was made from the high rate of actions taken to faults and the lower amount of false alarms generated by these hospitals. The local fire departments in these three places all had positive comments and thoughts regarding their local hospitals. The inspectors generally had good experiences with these hospitals as well.

  • Öberg, Oscar
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Lager & hantering av skivmaterial: Utvecklingsarbete hos Reklamcentra produktion2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report describes a bachelor program thesis in Technical design with orientation to production design carried out via Luleå University of Technology. The project has been performed at Reklamcentra Produktion Sverige AB and comprises 15 higher education credits.

    Reklamcentra produce and install exposure solutions, from simple stickers to more complex signage solutions, and are especially known for their LED-illuminated engraving- and paperflex signs. As a background to the project assignment, there is a potential order for 300 - 600 paperflex signs to be delivered within a four month time interval. An order of this magnitude entails new needs and conditions. The project is oriented towards production development and aims to map the production activities in order to determine needs and ultimately result in an action proposal.

     

    The five phases of the project have been defined as; Mapping & analysis, Requirement specification, Idea & concept development, Evaluation & selection and Detail processing. The implementation has followed a cyclical process where the phases have been worked through in turns with postponed focus for each turn. The survey started with a broad perspective to create a good information base on existing flows, working methods, and perceived problems within the production. The information collection is mainly obtained from interviews and observations of staff.

    Furthermore, the production process for the paperflex sign was examined more thoroughly. The sign consists of three different sheet materials which all undergo more or less extensive CNC machining and are then assembled with LED strip and detail components. Identified problems from mapping & analysis were strongly associated with the sheet materials storage units and handling. A requirement specification was drawn up containing the requirements that the conceptual solutions sought to solve and thereby established a foundation for idea development.

    In order to seek inspiration and experience regarding sheet materials in similar applications, a benchmarking was carried out at a glass wholesaler. Two potentially applicable and, in principle, different storage systems were examined in consultation with the supplier for the respective storage systems. A layout model that represented the existing production environment was established in SketchUp in order to be able to quickly implement and discuss different solution proposals. Idea and concept development resulted in three concepts that went further and were evaluated against an evaluation matrix inherited by the requirement specification. Winning concept from the evaluation were processed in detail where the sheet storage unit was dimensioned, and a mezzanine floor was introduced as a measure to provide a better order in the production environment.

     

    Final concept proposal is presented in different investment levels that can be implemented step by step. As a first measure, a new storage system is presented for arranging sheet materials and making them easily accessible and the introduction of the lean tool 5S. In order to meet the requirements specification to the greatest extent, it is recommended to install a Telfer - system with a vacuum yoke that can pick and place sheets from storage unit and on to CNC mill for machining.As a recommendation for continued work it is suggested to further investigate the telfer solution with constructor in order to ensure the realization of this principle.

  • Elenius, Lars
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Social Sciences.
    Meeting between peoples: The Multicultural World Heritage of Gammelstad2019 (ed. 500)Book (Other academic)
    Abstract [en]

    The Sámi presence in Gammelstad and the lower river valley is reconstructed through court records, household strategies examinations and matrimonial records. As recently as the mid-19th century, many in the population could speak Sámi, Finnish or Swedish. We can also trace the collective memory regarding Sámi settlements in villages such as Rutvik, Alvik and Måttsund. There are place names there such as Lappgärdan as a topographical reminder of Sámi who lived there. The book also sheds new light on the early Finnish-speaking population in the coastal area. From the history of the 20th th century there are accounts of how Finnish war children in all haste had to leave Finland that was in the throes of a war with the Soviet Union. The first war children arrived in 1942 and were boarded out to families. Some of them remained even after the war.

  • Öberg, Maria
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Sjöholm, Jennie
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Architecture and Water.
    Undermarksplanering: Svensk praxis utifrån valda projekt2019Report (Other academic)
    Abstract [en]

    This study was carried out as part of the research project Sustainable use of the subsurface (2017–2019). The project aims to support the sustainable use of the underground space, and to clarify new possibilities for how underground matters can be integrated into urban planning.

    The purpose of this study was to investigate how planning processes for facilities and other underground operations are carried out in Sweden, how the interaction between planning above and below ground works, how underground information is handled in different types of projects, and indicate opportunities for improvement.

    The report is based on studies of a number of completed underground projects, where public planning documents have been examined and interviews with people who have had insight into the projects have been carried out. The study has identified a number of suggestions that could help improve the planning process for underground planning:

    Systematic and accessible information

    • Collect geoscientific information (including interpretations) from all underground projects in a common database.
    • Ensure that project owners and clients submit geoscientific information to such a common database.
    • The information should be archived and made searchable digitally with regard to confidential information.
    • The archives should be managed so that relevant material remains available for the appropriate length of time.

     

    Cooperation

    • Create a good collaboration climate early in the project, with relevant stakeholders.
    • Support harmonization of the application of regulations between municipalities.

     

    Strategic work

    • A coherent planning for land use above and below land at the various stages of the planning process.
    • Sub-regional resources in a regional perspective are highlighted in regional planning documents.
    • Managing target conflicts at an early stage by making them visible in both national and regional and local planning.
    • Ensure that the right level of information is developed for the various stages of the planning processes.
  • Elenius, Lars
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Social Sciences.
    Möten mellan olika folk: den mångkulturella kyrkstaden i Gammelstad2019 (ed. 1)Book (Other academic)
    Abstract [sv]

    Genom domstolsprotokoll, husförhörslängder och giftermålslängder för att rekonstrueras den samiska närvaron i Gammelstad och den nedre älvdalen. Ännu i mitten av 1800-talet talade många i befolkningen samiska, finska eller svenska. Vi får också följa det kollektiva minnet efter samiska bosättningar i byar som Rutvik, Alvik och Måttsund. Där finns platser som kallas Lappgärdan som minnen i landskapet efter samer som bott där. I boken sätts också den tidiga finskspråkiga befolkningen i kustområdet i ny belysning. Från 1900-talets historia beskrivs hur finska krigsbarn tumultartat fick lämna ett Finland i fullt krig med Sovjetunionen. De första krigsbarnen anlände 1942 och utplacerades i familjer. En del av dem blev också kvar efter kriget.

  • Moulianitakis, Feidias
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Asimakopoulos, Konstantinos
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    Benchmarking Framework for Transparent Data Encryption Systems2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In the digital world of today, information is always at risk regardless of its state, at rest or in transit. Cryptography is the technology that promises to address the security issues that emerge. Hence, it was a reasonable consequence to introduce cryptography to databases. However, manually encrypting and decrypting data along with the key management is a burden for the regular user of a database. The need for removing this burden gave birth to Transparent Data Encryption (TDE).

     

    TDE technology is widely available nowadays and a number of vendors have developed their own solutions for protecting data at rest in a transparent way to the end user. However, cryptographic operations are resource intensive and introduce an overhead to the computational operations. The burden of cryptographic operations has drawn the interest of both academia and the industry for a long time before TDE appeared on the horizon. Hence, a lot of research has been done to measure the performance impact of those operations.

     

    Despite the extensive study for the performance of cryptographic algorithms, the performance of the TDE systems and the add-on computational burden for the introduced encryption has not yet been studied thoroughly. As a result, the current Thesis project tries to develop a theoretical benchmarking framework that evaluates the performance of Transparent Data Encryption systems. The study is conducted utilizing the Design Research methodology.

     

    The developed benchmarking framework focuses on the basic performance metrics of TDE systems, Elapsed time, CPU time and Hard Disk memory consumption. These metrics are calculated for varying key lengths, encryption algorithms and table sizes.  The framework follows a five - step procedure that includes the creation of topology - lab environment, creation of databases and definition of scenarios, activation of TDE feature, sequencial execution of scenarios and analysis of the results. The developed framework is evaluated by applying it on real TDE systems.

  • Islam, Raihan Ul
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Ruci, Xhesika
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Hossain, Mohammad Shahadat
    Department of Computer Science and Engineering, University of Chittagong, Chittagong, Bangladesh.
    Andersson, Karl
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Kor, Ah-Lian
    School of Computing, Creative Technologies and Engineering Leeds Beckett University, Leeds, UK.
    Capacity Management of Hyperscale Data Centers Using Predictive Modelling2019In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, no 18, article id 3438Article in journal (Refereed)
    Abstract [en]

    Big Data applications have become increasingly popular with the emergence of cloud computing and the explosion of artificial intelligence. The increasing adoption of data-intensive machines and services is driving the need for more power to keep the data centers of the world running. It has become crucial for large IT companies to monitor the energy efficiency of their data-center facilities and to take actions on the optimization of these heavy electricity consumers. This paper proposes a Belief Rule-Based Expert System (BRBES)-based predictive model to predict the Power Usage Effectiveness (PUE) of a data center. The uniqueness of this model consists of the integration of a novel learning mechanism consisting of parameter and structure optimization by using BRBES-based adaptive Differential Evolution (BRBaDE), significantly improving the accuracy of PUE prediction. This model has been evaluated by using real-world data collected from a Facebook data center located in Luleå, Sweden. In addition, to prove the robustness of the predictive model, it has been compared with other machine learning techniques, such as an Artificial Neural Network (ANN) and an Adaptive Neuro Fuzzy Inference System (ANFIS), where it showed a better result. Further, due to the flexibility of the BRBES-based predictive model, it can be used to capture the nonlinear dependencies of many variables of a data center, allowing the prediction of PUE with much accuracy. Consequently, this plays an important role to make data centers more energy-efficient.

  • Almqvist, David
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences.
    Ett rättviseperspektiv på bodelning vid äktenskapsskillnad2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I detta examensarbete behandlas rättvisa inom bodelning inom ramen för den svenska äktenskapsbalken. Specifika frågeställningar är om bodelningen är rättvis utifrån filosoferna John Rawls och Robert Nozicks syn på rättvisa, men även lagstiftarens syn på rättvisa behandlas. Undersökningen visar att den svenska äktenskapsbalken uttrycker en mildare version av Rawls rättvisa. Rawls förespråkar en form av rättvisa där rättsstaten ska försöka utjämna olikheter mellan individer vid födsel men också ojämlikheter som kan uppstå under livets gång. Nozick förespråkar större frihet; alla ska oavsett klass, handikapp eller andra ojämlikheter, leva efter samma regler, även om detta leder till en sämre tillvaro för de som inte har samma förutsättningar. En av uppsatsens slutsatser är att Rawls hade uppskattat att den svenska bodelningen baseras på likadelningsprincipen – dvs. försöker utjämna egendomsförhållandena mellan makar vid äktenskapsskillnad – medan Nozick hade varit emot försöken att kontrollera individens fria val. Vilken syn på rättvisa lagstiftaren har utgått från för bodelning visade sig vara en svår fråga att svara på. I förarbetena till äktenskapsbalken diskuteras rättvisa betydligt mer, men inte heller här ges något konkret svar på lagstiftarens syn på rättvisa inom bodelning. Arbetet behandlar endast bodelning vid äktenskapsskillnad där båda makarna är vid liv och endast med utgångspunkt i två filosofers, Rawls och Nozicks, respektive uppfattning av rättvisa.

  • Börjesson, Johan
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering.
    SNMP-Proxy för SMF marknaden: Kan SNMP-proxy vara lösningen för att realisera SNMP som tjänst till SMF marknaden?2019Independent thesis Basic level (university diploma), 80 credits / 120 HE creditsStudent thesis
  • Jan, Petra
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Thermomechanical characterisation of newly developed UHMWPE composites2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Ultra high molecular weight polyethylene (UHMWPE) is a polymer commonly used in various applications, particularly in hip joint replacements. Despite its good performance, it is susceptible to oxidation degradation, which can be mitigated with the addition of vitamin E, and to excessive wear against metal countersurfaces, which can potentially be improved with the addition of nanoparticles. In this work, sixteen newly developed UHMWPE nanocomposites with different nanofillers (multi-walled carbon nanotubes, graphene oxide and nanodiamonds), blended with and without vitamin E, and both irradiation crosslinked and non-crosslinked were studied. Thermomechanical characterisation (dynamic mechanical analysis and thermogravimetric analysis) and tribological pin-on-disc testing showed that both nanofillers and the addition of vitamin E ensured improved the performance of the nanocomposites compared to the virgin UHMWPE. Vitamin E improved the oxidative and thermal stability of UHMWPE, decreased the wear and increased the coefficient of friction. The nanoparticle reinforcements contributed to improved thermal stability to some degree and decreased the wear. Crosslinking was also shown to result in improved thermomechanical performance, although it appears that the addition of vitamin E inhibits the crosslinking process.

  • Lindberg, Liv-Johanna
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Industrilized and sustainable construction.
    Ständiga förbättringar genom teorin kring single- och double-loop learning: En fallstudie av Skanskas arbetssätt och strukturer2019Independent thesis Advanced level (professional degree), 300 HE creditsStudent thesis
    Abstract [en]

    Which method is the best to collect all the employees’ information, data and experiences? Furthermore, how does all the information reach the whole organization? These questions have been investigated for a long time in the building sector. Earlier studies and graduation works have looked into experience feedback and continuous improvement and it is something that needs to be more investigated since it still does not work to its fully potential.

     

    This study looks into one of Sweden’s biggest construction entrepreneurs, Skanska, and how the organization can be compared to a learning organization. The study investigates two main things; one is how the employees uses experience feedback and how they find experiences in the company. The other part looks into one of the main structures in the company that focuses on experience feedback, called PiV-meetings, World Class Projects-meetings.

     

    The purpose with the study is to evaluate Skanska Sweden’s work with experience feedback today and how it could be developed. Evaluate if it consists parts in the flow of experiences that does not work to its fully potential, which can prohibit the distribution of experiences out in the whole organization. The purpose is also to look into PiV-meetings and see if the meetings is a good tool for experience feedback.

     

    The study has been conducted as a qualitative study and has been focusing on a large region in Sweden. Seven interviews were held whereas six of them was so called semi-structured interviews and one of them was a starting interview to get an understanding of the organization and its work regarding experience feedback.

     

    The result shows two focuses for the organization. One is to be clearer with the purpose for the PiV-meetings and be a little harder with consequences for the ones who do not follow Vsaa. The other result shows that based on the theoretical base in this study, single- and double-loop learning, Skanska needs to be a little better with the reach of the PiV-meetings results. Making sure that they really reaches the highest “top” in the organization and therefore creates a double-loop learning.

     

    The recommendation from this study is to follow up the PiV-meetings and really see that the double-loop learning occurs in the organization. The result based on the studied region shows that in the region does the experience feedback work well, but it needs to be good in the whole organization to classify Skanska as a complete learning organization.