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  • 1.
    Eidehall, Andreas
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Lane Game: Lane Guidance Systems Are Now Emerging onto the Vehicle Market2005In: Traffic Technology International, ISSN 1356-9252, 40-42 p.Article in journal (Refereed)
    Abstract [en]

    This article describes the difficulties in developing an automotive lane guidance system, as well as Volvo's possible solution. Lane guidance aims to keep drivers from drifting into another lane by monitoring lane markings with a vision system that alerts the driver with an audio warning, a vibration, or a small amount of steering wheel torque to keep the vehicle in the lane. The difficulties in making such systems work, however, are many: false alarms when changing lanes intentionally, curve cutting by drivers, or driver reliance on a system while they changed CDs or checked text messages. The article describes in detail how Volvo is evaluating a system that shows promise.

  • 2.
    Björkroth, Jennie
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Effekter av naturvårdsgallring på förekomsten av lunglav på ädellövträd2015Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    Sun-exposed broad leaved deciduous trees have a great species diversity of epiphytic lichens. In Europe, these trees have decreased dramatically in number as wooded pastures have become overgrown with trees and bushes, and broad leaved deciduous stands have been replaced by planted coniferous trees. These are the main reasons for many lichens depending on deciduous trees being red-listed. Epiphytic lichens in overgrown areas could benefit from conservation thinning, but few studies have been performed on how this type of cutting affects the lichens. In a previous study, the presence of red-listed epiphytic lichens in a broad leaved deciduous forest was examined. After the study, thinning of trees and bushes was made. Here we study the effects of this thinning on Lobaria pulmonaria. We tested possible factors that may affect the growth of L. pulmonaria, and if there were any differences in incidence and vitality of the lichen between managed and unmanaged stands. Since Dutch elm disease and ash dieback are well spread in the area, we wanted to see if they also affected the growth of L. pulmonaria. There were no differences in incidence and growth between managed and unmanaged stands. The results were unexpected since other studies show that, for instance, increased sun exposure often has a great effect on the growth of lichens. Many elms and ashes were dead or dying and had a significant negative effect on the change of number of lobes and the lobe surface. The diseases of the trees can thus be assumed to be the greatest cause of why the lichens in the managed stand did not benefit from thinning.

  • 3.
    Ödling, Mattias
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, Faculty of Science & Engineering.
    How Provider Value is Perceived in regards to Integrated Product Service Offerings and why: A case study2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As companies grow larger and become more international, it is likely that it comes to a point where it would be cheaper to produce on site, or at least have distribution centers, rather than having a centralized production that requires long range shipping. As this occurs, there is a wide range of challenges that the company must face, however these challenges are by now well documented and while not to be underestimated and called “easy” it is nothing new as a wide range of companies have done it before. One aspect that however is less known is the influence that external differences has, in other words factors that would produce a differing result even with the exact same internal setup, on the perceived aspects (referred to as Values in this work) from the providers point of view. In particular what is interesting is the perceived positive impacts above expectations that is gained from having external differences. To be able to better understand and quantify this impact the term “Provider Value” has been created and is being researched towards understanding what Values exist and how they are being affected.Provider Value (PV) is a cutting edge concept within eco-design research that this work is based on and in particular ProVa – Provider Value Evaluation for Integrated Product Service Offerings (Matschewsky et al. 2015) is the latest step to date towards creating the tools needed to increase the utilization, and reap the benefits, of PVs. Another interesting and relevant aspect to PV is how Product/Service System (PSS) could be an essential part in paving a new way of avoiding increased environmental impact while having economic growth. This is done by adding services on top of already existing products (Sakao et al. 2009).To find out more about what kind of external factors that might be behind the differences a case study was conducted, interviewing employees at two companies within one concern in Sweden and Japan. The results of this work indicates that if the company want its PVs to remain the same the main obstacle is external economic differences. In this particular study it is also clear that differences in business model and company structure has a big impact. With all the discussion regarding environment it was on a surprisingly low level of interest at both companies and what mattered was that the products cleared the minimum requirements, nothing more, as “any additional return is hard to estimate”. If PV keeps growing and tools are made to assist, this could not only help simplify the transitioning to other countries and help utilizing existing Values from the start, it could also increase the utilization in general, in particularly in regards to the Environment.

  • 4.
    Hildebrand, Cisilia
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Hörtin, Stina
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    A comparative study between Emme and Visum with respect to public transport assignment2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Macroscopic traffic simulations are widely used in the world in order to provide assistance in the traffic infrastructure development as well as for the strategic traffic planning. When studying a large traffic network macroscopic traffic simulation can be used to model current and future traffic situations. The two most common software used for traffic simulation in Sweden today are Emme and Visum, developed by INRO respective PTV.

    The aim of the thesis is to perform a comparison between the software Emme and Visum with respect to the assignment of public transport, in other words how passengers choose their routes on the existing public transport lines. However, in order to make a complete software comparison the run-time, analysis capabilities, multi-modality, capacity to model various behavioural phenomena like crowding, fares etc. this will not be done in this comparison. It is of interest to study the differences between the two software algorithms and why they might occur because the Swedish Transport Administration uses Emme and the Traffic Administration in Stockholm uses Visum when planning public transport. The comparison will include the resulting volumes on transit lines, travel times, flow through specific nodes, number of boarding, auxiliary volumes and number of transits. The goal of this work is to answer the following objective: What are the differences with modelling a public transport network in Emme and in Visum, based on that the passengers only have information about the travel times and the line frequency, and why does the differences occur?

    In order to evaluate how the algorithms work in a larger network, Nacka municipality (in Stockholm) and the new metro route between Nacka Forum and Kungsträdgården have been used. The motivation for choosing this area and case is due to that it is interesting to see what differences could occur between the programs when there is a major change in the traffic network.

    The network of Nacka, and parts of Stockholm City, has been developed from an existing road network of Sweden and then restricted by "cutting out" the area of interest and then removing all public transportation lines outside the selected area. The OD-matrix was also limited and in order not to loose the correct flow of travellers portal zones was used to collect and retain volumes.

    To find out why the differences occur the headway-based algorithms in each software were studied carefully. An example of a small and simple network (consisting of only a start and end node) has been used to demonstrate and show how the algorithms work and why volumes split differently on the existing transit lines in Emme and Visum. The limited network of Nacka shows how the different software may produce different results in a larger public transport network.

    The results show that there are differences between the program algorithms but the significance varies depending on which output is being studied and the size of the network. The Visum algorithm results in more total boardings, i.e. more passengers have an optimal strategy including a transit. The algorithms are very similar in both software programs, since they include more or less parts of the optimal strategy. The parameters used are taken more or less into consideration in Emme and Visum. For example Visum will first of all focus on the shortest total travel time and then consider the other lines with respect to the maximum waiting time. Emme however, first focuses on the shortest travel time and then considers the total travel time for other lines with half the waiting time instead of the maximum wait time. This results in that less transit lines will be attractive in Emme compared to Visum. The thesis concludes that varying the parameters for public transport in each software algorithm one can obtain similar results, which implies that it is most important to choose the best parameter values and not to choose the "best" software when simulating a traffic network.

  • 5.
    Wikberg, Sofia
    et al.
    Linköping University, Department of Management and Engineering, Production Economics. Linköping University, The Institute of Technology.
    Jerlström Hultqvist, Samuel
    Linköping University, Department of Management and Engineering, Production Economics. Linköping University, The Institute of Technology.
    Development of the S&OP process at Seco Tools AB: Aligned with today´s supply chain planning processes 2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Background:

    Companies strive to produce as close to customer demand as possible to reduce the cost, inventories, etc. One process that deals with this issue of balancing demand and supply is Sales & Operations Planning (S&OP). Seco Tools is a company with their head-office located in Fagersta, Sweden, which is experiencing high inventory levels and a need of cutting cost. The ongoing project Supply Chain Planning at Seco Tools resulted in the implementation of a new software which enables them to improve demand, inventory, and supply planning. As a result of the improved planning ability, a new S&OP process is developed and in need for improvement.

    Purpose:

    The purpose of this thesis is to evaluate the current S&OP process from the Supply Chain Planning project and to suggest future improvements for Seco Tools AB.

    Research objectives:

    1. Study and describe the current S&OP process at Seco Tools.

    2. Analyse and identify differences in Seco Tools’ S&OP process compared to the literature and a benchmark company.

    3. Perform deeper analyses within financial integration and the use of KPIs in Seco Tools´ S&OP process.

    4. Suggest future improvements to Seco Tools regarding their S&OP process based on the identified differences from research objective 2 and the deeper analysis from research objective 3.

    Method:

    The planning report set the framework for the carrying through of the thesis. A literature study regarding S&OP and a case study performed at Seco Tools regarding their S&OP have been done in parallel. Seco Tools’ S&OP process has been studied and described with the help of interviews, observations, and internal documents. Analysis was made where Seco Tools S&OP was compared to the theoretical S&OP and the S&OP at AstraZeneca. The analysis led to recommendations to Seco Tools regarding improvements in their S&OP process.

    Conclusions:

    Two opportunities for improvement were highlighted during the analysis of Seco Tools S&OP. They were financial integration and the use of cross-functional KPIs covering all the departments that were suggested to be involved in S&OP at Seco Tools. Seco Tools should integrate their finance in the process to compare S&OP against the business plan, and the company’s strategy should be well understood by the participants in S&OP. The knowledge of the company’s strategy together with the right authorities in the process will improve the decision making in Seco Tools’ S&OP. Seco Tools also need to implement an S&OP scorecard with KPIs that covers all departments in the company and the strategy as well. This helps to further develop cross-functionality and to early on make root cause analysis of identified problems. Cross-functionality and KPIs are believed to be general recommendations that all companies can use as well, not only something that Seco Tools can take advantage of. A template for an S&OP scorecard especially for Seco Tools has been made. It contains 16 cross-functional KPIs covering all steps and departments involved in S&OP at Seco Tools.

  • 6.
    Dalbato, A. L.
    et al.
    Swedish University of Agriculture Science, Sweden .
    Alfredsson, T.
    Swedish University of Agriculture Science, Sweden .
    Karlsson, L. M.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology. Swedish Univ Agr Sci, Sweden.
    Andersson, L.
    Swedish University of Agriculture Science, Sweden .
    Effect of rhizome fragment length and burial depth on emergence of Tussilago farfara2014In: Weed research (Print), ISSN 0043-1737, E-ISSN 1365-3180, Vol. 54, no 4, 347-355 p.Article in journal (Refereed)
    Abstract [en]

    Mechanical control of Tussilago farfara is carried out mainly by soil cultivation. The aim is to deplete the energy stored in the rhizomes. The treatment includes cutting the rhizomes, to stimulate increased shooting, followed by renewed soil cultivation to destroy the shoots and incorporate them into the soil. Factors generally regarded as important in the control of perennial weeds are extent of fragmentation and burial depth. In this study, the importance of these two factors on T. farfara emergence was studied in detail in two pot experiments. Rhizomes were cut into different lengths (5-25 cm) and buried at various depths (1-42 cm) in pots filled with peat soil or clay loam. Shoot germination, emergence and early plant performance were studied. Intensive fragmentation and deep burial (possible to achieve using conventional tillage) are not enough to completely hinder emergence of T. farfara; 6-cm fragments emerged and developed normal leaves from 42 cm depth, regardless of soil type. However, there were higher total emergence and emergence rates in peat soil than in clay soil. Burial depth was correlated with time to emergence; burying rhizome fragments, not longer than 25 cm, to at least 20 cm depth gave a time to emergence of at least 20 days. The delay of weed emergence should allow good establishment of a crop and ensure a significant competitive effect against T. farfara.

  • 7.
    Axelsson, Peter
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Petersson, Jonas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Remote Tower Centre - Configuration and Planning of the Remote Tower Modules2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today, many small aerodromes have a hard time surviving economically, and amongst the largest cost is air traffic control. Airlines are cutting costs where they can, and many times this affects the aerodromes as well, e.g. when airlines decide to park remotely instead of at the gate. The project called Remotely Operated Towers, initiated by SESAR and run by Saab and LFV, is aiming to address this problem. The project revolves around remotely providing ATS to aerodromes where it is deemed suitable. A big challenge in this project is how to assign aerodromes to remote tower modules in the remote control centre. There are many ways to do this, but there is only a few ways to do it to achieve the least amount of modules. This thesis aims to find an optimal solution to the challenge mentioned above. The thesis resulted in a model where the user can provide the input of choice, i.e. aerodromes with associated ATS operating hours and movements, for a specific period – and receive the assignment schedule for the modules, saying exactly which aerodrome are to be controlled by which module at what time.

  • 8.
    Hökerberg, Camilla
    Linköping University, Department of Management and Engineering, Carl Malmsten - furniture studies. Linköping University, The Institute of Technology.
    Intarsia i läder: Intarsiateknikens tillämpbarhet inom tapetserarens arbetsfält2012Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    This thesis examines the conditions for the intarsia technology’s applicability in the upholsterer’s field. I have by studying the different crafts and techniques in Intarsia gained a greater understanding of these and able to reflect on their use for upholstery tasks. After trying and comparing different techniques, materials and approaches and traded my experiments in a chair outfit I have come to the following: When comparing and evaluating the results it is evident that among the varying leather materials and adhesives I´ve tried there is no one more preferable, nor unpreferable, than the other. All materials included in my study works well on both arched and flat surfaces, on hard as well as on soft surfaces - under the circumstances for which I give a detailed account in my work. My experiments so far have also shown that both the approach I have chosen, cutting out the pattern by hand and laser cutting, are associated with problems that make the technology difficult in the current situation incompatible with the requirement of labor economics and precision. Punching is probably the most interesting technology, but the technology was not included in the study.

  • 9.
    Tälle, Malin
    Linköping University, Department of Physics, Chemistry and Biology, Ecology. Linköping University, The Institute of Technology.
    Management of semi-natural grassland vegetation: long-term effects of grazing, mowing and different mowing techniques2013Independent thesis Advanced level (degree of Master (Two Years)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Semi-natural grasslands are species-rich and one of the most threatened habitats in Europe, since land-use changes have led to reduced area of grassland. Appropriate management practices like grazing or mowing is needed to maintain the conservation values and species-richness of semi-natural grasslands. However, few studies have investigated which of grazing or mowing is most appropriate. Furthermore, almost no studies have investigated which mowing technique is best for the conservation value of grassland flora. The aim of this study was to determine which management practice of grazing and mowing, and which mowing technique, has the most positive effect on grassland flora. Data from two long-term trials were evaluated: one compared the effect of grazing and mowing in eleven sites in southern Sweden during at least twelve years; the other compared the effect of the knife mower and grass trimmer at different cutting heights in one site during twelve years. Meta-analysis was used, based on the odds for a plant record being an indicator species, using eight different indicator systems of classification of grassland plants. Over time, results show increasing odds of finding indicators of good management and no change in odds of finding indicators of lack of management in mowed compared to grazed plots. There were no differences in the odds of finding any indicator species for any of the mowing techniques. Hence, to maintain the conservation values of semi-natural grasslands, mowing is the better management practice compared to grazing. Mowing using a knife mower or grass trimmer has similar effects, and can both be recommended.

  • 10.
    Vukania Adda, Nancy
    et al.
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    Qin, Xiaochen
    Linköping University, Department of Management and Engineering, Business Administration. Linköping University, Faculty of Arts and Sciences.
    Long Term Cost Efficiency through Green Management Control Systems2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Title: Long term cost efficiency through green management control systems.Authors: Nancy Vukania &Xiaochen QinSupervisor: Åsa Karin-EngstrandBackground: The worldwide financial crisis of 2008 has reconfigured the economic turf leading to a more uncertain and turbulent playing field – a greater challenge for business strategy and the quest for optimization- The oil price hike of 2008 (Furlong 2010)1 caused its rippling effect to affect various cost categories including energy, labor and logistics thus causing a roller coaster business decision making process regarding outsourcing, off shoring and internal control and cutting short the decision making term to make room for adjustments. Amidst this high volatility and turbulence of factor markets coupled with fierce competitor activity, organizations are being drawn towards alternative sources of cost advantage which can enable them pursue long-term profitability.Aim: With this research, we intend to introduce an idea of cost efficiency which in the long term has the potential to develop into cost leadership for mature public organizations who are facing uncontrollable instabilities from the external business eco-system as well as international legislation regarding environmental sustainability (United Nations Framework Convention on Climate Change)2. We aim to do this through studying an Energy performance contracting (EPC) project currently being undertaken by Landstinget I Östergotland (LIO), the county council of the province of Östergotland in Sweden.Results: We aim to prove- based on the results of the studied EPC project and the literature on green technology and management control systems- that the interplay of green technological systems and management control techniques can in the long term achieve substantial cost saving and profit making differentials that are sustainable, eco-friendly and subject to further development.Key Phrases/Words: Cost strategy, Management control, Green technology, Long-term SustainabilityPaper Type: Research Paper

  • 11.
    Kabir, MD
    et al.
    Linköping University, Department of Management and Engineering, Business Administration.
    Plantis, Jerome
    Linköping University, Department of Management and Engineering, Business Administration.
    The Influence of Firm's Human Resource andMarket Demand on a Firm's Innovation Strategy2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Background: In technology based industries, firms which originate from advanced economies have traditionally occupied the leading position. In order to keep that position, they relied on strong efforts devoted to research and development, striving for being at the cutting edge of technology. During the last decade, we observed that some change happened amongst the top ranking of firms within the telecommunication industry with the apparition of Huawei, which originates from China, an emerging economy, in second position.

    Aim: This research is aimed to investigate the influence of firm’s human resource and market demand on firm’s innovation strategy.

    Definitions: Human resource represents the employees working for a company. In our study, when we mention human resource we deal with employees working in research and development. Market demand refers to the products which are demanded on a specific market. For our research we divided it in three categories: less advanced, advanced and most advanced products. Innovation strategy deals with the way a firm organizes its research and development in order to innovate according to either, in our research, new-tofirm or new-to-world innovation strategy.

    Completion and results: This study revealed that Huawei managed to adjust its innovation strategy in accordance with its human resources and market demand. Thanks to an efficient and adapted innovation strategy, Huawei now manages to perform better than its main competitor Ericsson, not only on developing or emerging markets, but also in advanced markets. We also observed the role of rules and regulations and cooperation, without which Huawei would not have been able to lead an efficient new-to-firm strategy. We created a model which is designed to give a better understanding of the situation and illustrate the interrelation between human resource, market demand, innovation strategy and performance.

  • 12.
    Skachkova, Katsiaryna
    Linköping University, Department of Management and Engineering, Business Administration.
    Voluntary turnover among technical consultants. Mediating role of social identities and perceived promises2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Background: Development of technologies and high pace of changes made a modern organization highly dependent on the expertise and assistance of technology specialists. To be able to compete and be cost efficient, but at the same time be on the cutting-edge of technology development, is an essential requirement for doing business in the contemporary world. Moreover, this requirement became a solid ground for the emergence of a technical consulting industry and a new type of human resources - technical consultants. On the one hand, technical consultants are the main resources of technical consulting organizations, but on the other hand, technical consultants can cause harm to technical consulting organization, particularly, in the case of voluntary turnover.

    Aim: Through the qualitative analysis of the four technical consultants’ voluntary turnover stories in Sweden and based on the literature review, this master thesis opens up the door to the world of technical consultants. The aim of this work is to seek new insights into the problem of voluntary turnover in a new context of technical consultants and discover what role multiple identities and perceived promises play in voluntary turnover decision.

    Results: Technical consultants are a type of knowledge workers with non-traditional work arrangements. Empirical evidence demonstrates that technical consultants’ decision to quit can be described using "Eight motivational forces", but the framework should be extended, due to developing multiple identities and receiving perceived promises from multiple sources.

  • 13.
    Geng, Qifeng
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Time-efficient Computation with Near-optimal Solutions for Maximum Link Activation in Wireless Communication Systems2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In a generic wireless network where the activation of a transmission link is subject to its signal-to-noise-and-interference ratio (SINR) constraint, one of the most fundamental and yet challenging problem is to find the maximum number of simultaneous transmissions. In this thesis, we consider and study in detail the problem of maximum link activation in wireless networks based on the SINR model. Integer Linear Programming has been used as the main tool in this thesis for the design of algorithms. Fast algorithms have been proposed for the delivery of near-optimal results time-efficiently.

    With the state-of-art Gurobi optimization solver, both the conventional approach consisting of all the SINR constraints explicitly and the exact algorithm developed recently using cutting planes have been implemented in the thesis. Based on those implementations, new solution algorithms have been proposed for the fast delivery of solutions. Instead of considering interference from all other links, an interference range has been proposed. Two scenarios have been considered, namely the optimistic case and the pessimistic case. The optimistic case considers no interference from outside the interference range, while the pessimistic case considers the interference from outside the range as a common large value. Together with the algorithms, further enhancement procedures on the data analysis have also been proposed to facilitate the computation in the solver. 

  • 14.
    Gustafsson, E.
    et al.
    Combitech AB, P.O. Box 15042, 580 15 Linköping.
    Hofwing, Magnus
    Department of Mechanical Engineering Jönköping University P.O. Box 1026, 551 11 Jönköping.
    Strömberg, N.
    Department of Mechanical Engineering Jönköping University P.O. Box 1026, 551 11 Jönköping.
    Residual stresses in a stress lattice: experiments and finite element simulations2009In: Journal of Materials Processing Technology, ISSN 0924-0136, Vol. 209, no 9, 4320-4328 p.Article in journal (Refereed)
    Abstract [en]

    In this work, residual stresses in a stress lattice are studied. The residual stresses are both measured and simulated. The stress lattice is casted of low alloyed grey cast iron. In fact, nine similar lattices are casted and measured. The geometry of the lattice consists of three sections in parallel. The diameter of the two outer sections are thinner than the section in the middle. When the stress lattice cools down, this difference in geometry yields that the outer sections start to solidify and contract before the section in the middle. Finally, an equilibrium state, with tensile stresses in the middle and compressive stresses in the outer sections, is reached. The thermo-mechanical simulation of the experiments is performed by using Abaqus. The thermo-mechanical solidification is assumed to be uncoupled. First a thermal analysis, where the lattice is cooled down to room temperature, is performed. Latent heat is included in the analysis by letting the fraction of solid be a linear function of the temperature in the mushy zone. After the thermal analysis a quasi-static mechanical analysis is performed where the temperature history is considered to be the external force. A rate-independent J2-plasticity model with isotropic hardening is considered, where the material data depend on the temperature. Tensile tests are performed at room temperature, 200 °C, 400 °C, 600 ° C and 800 ° C in order to evaluate the Young’s modulus, the yield strength and the hardening accurate. In addition, the thermal expansion coefficient is evaluated for temperatures between room temperature and 1000 °C. The state of residual stresses is measured by cutting the midsection or the outer section. The corresponding elastic spring-back reveals the state of residual stresses. The measured stresses are compared to the numerical simulations. The simulations show good agreement with the results from the experiments.

  • 15.
    Jover Casanovas, Elena
    Linköping University, Department of Management and Engineering, Carl Malmsten - furniture studies.
    Can laser cutting be an alternative technique for marquetry completion in furniture conservation?2011Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    This study describes experiments and findings of an investigation to evaluate the use of laser cutting as an alternative to traditional sawing techniques in marquetry completion conservation.

    Experiments on veneer from 11 different species of wood, covering ring porous, semi-diffuse/-ring porous and diffuse porous woods, were carried out and examined. The optimal cutting metrics with respect to speed, power and frequency for the types of wood were determined. The most important ethical question for a conservator is to be able to preserve as much as original material as possible. The results of this project show that the use of a laser cutting machine is indeed a suitable solution to produce replacement veneer for marquetry works in furniture conservation with respect to quality and time. Especially when it comes to the precision in the shape of the replacement piece, laser cutting is superior to hand sawing. This makes laser cutting an interesting option and reduces the need for expert skills in hand sawing in order to perform very detailed completion work. It also reduces the need of invasive work on the original marquetry to accommodate the replacement piece.

    The findings are general for all of the examined types of wood. On the negative side, the laser cutting machine requires a relatively big initial investment, making it difficult to say if it is really a cost-effective method of cutting replacement veneer pieces.

  • 16. Engvall, Gustav
    et al.
    Bergström, Fredrik
    Linköping University, Department of Science and Technology, Media and Information Technology.
    Development of handheld mobile applications for the public sector in Android and iOS using agile Kanban process tool2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The innovation progress for municipalities is currently going slowly. Today most of the communication, decision-making, delegation and service of process are still handled via letter mail or phone calls. Companies and municipalities are starting to comprehend this and see opportunities. With the technology that exists today it is possible to speed up the processes when citizens and municipalities comunicate with each other. By migrating from the old way of applying and filing different matters by letter mail to so-called digital e-services, the citizen can apply, complement and get info on how their matter is going directly on the web. Abou AB works with optimizing information handling for municipalities and has recently made it possible for municipalities to eliminate their tedious way of handling matters by traceable web communication. They have a vision to take this to a new level of easement to the municipalities and their citizens by offering these services in mobile phones as so-called apps. One of these contemplated services is to file error reports. The service will offer the citizen to send in a report with attached meta data such as photo and the location of the regarding matter. This will be done by the mobile phones built in hardware in form of camera and GPS. This master’s thesis will describe the work to develop a prototype for filing an error reports in mobile phones that support Android and iOS operating systems.

    The goal for this thesis work is to develop this prototype by means of a process tool called Kanban and investigate if the tool fits the situation properly. The situation is that two persons will work in parallel with slightly different projects. Also the quality and usability of the resulting prototype applications is asserted with qualitative evaluations that results in higher awareness of the defects and suggestions on how to reform and improve the application in a usability point of view.

    The actual implementation work was planned according to a slightly loose Kan- ban paradigm. Kanban is all about improvements along the way and the im- plementation phase is divided into smaller phases with sub goals and recurring process evaluations. Suggestions of improvement regarding the work processes is a result of this. A Kanban board that helps visualize the workflow is used to help team members and project owners to get a good overview of current situa- tions. Several adjustments were made throughout the project and the so-called lead times, the time it takes to complete a task, was shortened in average from the beginning of the project compared to the end of the project.

    Each phase in the implementation part of the thesis work resulted in different functionalities in the application. A phase was two weeks long and ended with a demo were the new functionality was demonstrated. Prior to each demo session everyone at the company where the thesis work was performed was invited. The participants in these sessions were encouraged to give feedback on what they saw to help increase the quality of the applications. The prototype applications resulted in a more easy accessible service to citizens. By cutting out the process steps that previously needed to been done on a computer the

    1application contributes to the possibility of an increased democratization grade for the citizen.

    The investigation regarding if the Kanban process tool was a suitable aid in the implementation part of the project resulted in that it was suitable for the specific situation. By measuring both lead times and other activities that did not concern the implementation work and plot them in a diagram explained why some weeks did not have as high productivity as others.

    To assert the awareness and quality of the developed applications in terms of usability a so-called heuristic evaluation was performed. This qualitative eval- uation resulted in a set of usability problems. These problems were all graded into different priority to be solved and some was given suggestions on how to be solved. The main purpose with this evaluation was to find the problems and document them to possible future programmers if the prototype will go into production. The result of this evaluation has increased the usability of the application and consequently the quality.

  • 17.
    Thelin, Victor
    Linköping University, Department of Management and Engineering, Carl Malmsten - furniture studies.
    Laserskuren intarsia: ett komplement till äldre intarsiatekniker2010Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this report is to explore how modern technology can work againstolder craft techniques. The focus of the research will depend on what conditions areoptimal for cutting marquetry with laser technology. In my work I account for thehistorical background of the various techniques and then through own practical testsexamine whether the laser technology can complement the traditional techniques.

  • 18.
    Nilsson, Daniel
    Linköping University, Department of Electrical Engineering.
    Flexibel ljudinspelning för talkvalitetsanalys2010Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report describes how wavefiles can be recorded with programs written in the C++ language . The report also describes how the recorded sound is handled before it can be analyzed. The report describes the different parts that make a wave file to a wave file and how Windows handle these files. There is always some silence or noise of unknown length that passes through the system before some interesting sound arrives. That silence or nose must not be recorded and therefore some function must be developed that can detect interesting sound or speech. Besides of that this report handle the problem of cutting a longer wave file into smaller parts and how to down sample recorded files and files that have been cut.

  • 19.
    Löfqvist, Martin
    Linköping University, Department of Management and Engineering.
    On the Valuation of ‘Big Pharma’s’ Research Pipelines2009Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Background: Tougher demands from regulators on drugs efficiency and safety,governmental cost cutting and more complex areas of research, has led to that the importance of the pharmaceutical industry’s research pipelines are increasing. Even though the capital markets views on the pharmaceutical industry and its valuation is changing, the authors is not aware of any prior research that has been conducted on the topic of how the market reacts to clinical trial results or how security analysts valuates product pipelines.

    Aim: This thesis aims to explain how security analysts valuate research pipelines and analyze whether the publication of clinical trial results significantly affects the pricing of multinational pharmaceutical companies.

    Methodology: Three econometric models using an aggregate daily data sample of 27 years for five of the world’s largest pharmaceutical firms distinguish the price effects related to the publication of clinical trial results. Three interviews with security analysts map how security analysts value pharmaceutical research.

    Results: Security analysts’ uses a combination of DCF and relative valuation when analyzing pharmaceutical firms. All interviewed analysts uses a risk adjusted net present value approach which is closely linked to the DCF approach, however, financial theory suggests that pipelines should be valuated with contingent claim models Analysts recognize that all compounds in Phase III and some Phase II projects has a impact on firm value. Clinical trials have a significant short-term impact on firm value. Phase III projects shows significant share price influence whilst early stage clinical trials do not, which shows that analysts are correct in focusing their valuation to later stage clinical trials. However, not all areas of therapy have a significant impact on firm value. Oncology is the only area of therapy where successes raises firm value, whilst failures in oncology and cardiovascular/gastrointestinal significantly lower firm value. Negative news about the research portfolio also tends to have a larger impact than positive news.

  • 20.
    Dilner, David
    Linköping University, Department of Physics, Chemistry and Biology.
    Behavior of cutting tool coating material Ti1-xAlxN at high pressure and high temperature2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The high pressure and high temperature (HPHT) behavior of Ti1-xAlxN coatings on cutting tool inserts have been of interest for this diploma work. A literature study of HPHT techniques as well as measurement methods has been done. A diamond anvil cell (DAC) would be a good device to achieve high pressure and high temperature conditions on small samples. Another way to obtain these conditions would be a cutting test, which has been performed on a Ti1-xAlxN coated cutting tool insert with x = 0.67. Also a cubic press could be used to apply HPHT on a     Ti1-xAlxN sample or a large volume press on a whole cutting tool insert. To measure hardness on thin coatings a nanoindentor could be used, which have been done on heat-treated Ti0.33Al0.67N and TiN samples. X-ray diffraction (XRD) is a suitable method to measure phase composition of a sample and was performed on the cutting tested insert as well as on an untreated reference insert. Three ways to continue this project have been outlined all starting with more comprehensive cutting tests.

  • 21.
    Wallén, Johanna
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Norrlöf, Mikael
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Gunnarsson, Svante
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Experimental Evaluation of ILC Applied to a Six Degrees-of-Freedom Industrial Robot2007In: Proceedings of the 2007 European Control Conference, 2007Conference paper (Refereed)
    Abstract [en]

    Experimental evaluation of an Iterative Learning Control (ILC) algorithm is presented. The ILC algorithm is applied to all motors of a large size commercial six degrees-of-freedom industrial robot in order to minimise the error measured on the motor angles. The performance of the algorithm is evaluated with respect to the operating point of the robot, the programmed tool velocity, and the design variables of the ILC algorithm. The chosen movements are intended to represent typical paths in a laser cutting application. Even though a fairly simple ILC algorithm is applied, the error reduction is substantial after only five iterations and the algorithm shows good robustness properties.

  • 22.
    Wallin, Ragnar
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Kao, Chung-Yao
    University of Melbourne, Australia.
    Hansson, Anders
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A Cutting Plane Method for Solving KYP-SDPs2006Report (Other academic)
    Abstract [en]

    Semidefinite programs originating from the Kalman-Yakubovich-Popov lemma are convex optimization problems and there exist polynomial time algorithms that solve them. However, the number of variables is often very large making the computational time extremely long. Algorithms more efficient than general purpose solvers are thus needed. To this end structure exploiting algorithms have been proposed, based on the dual formulation. In this paper a cutting plane algorithm is proposed. In a comparison with a general purpose solver and a structure exploiting solver it is shown that the cutting plane based solver can handle optimization problems of much higher dimension.

  • 23. Olovsson, Lars
    et al.
    Nilsson, Larsgunnar
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Solid Mechanics.
    Simonsson, Kjell
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Solid Mechanics.
    An ALE formulation for the solution of two-dimensional metal cutting problems1999In: Computers & structures, ISSN 0045-7949, Vol. 72, 497-507 p.Article in journal (Refereed)
  • 24.
    Wallén, Johanna
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Norrlöf, Mikael
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Gunnarsson, Svante
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Experimental Evaluation of ILC Applied to a Six Degrees-of-Freedom Industrial Robot2006Report (Other academic)
    Abstract [en]

    Experimental evaluation of an Iterative Learning Control (ILC) algorithm is presented. The ILC algorithm is applied to all motors of a large size commercial six degrees-of-freedom industrial robot in order to minimise the error measured on the motor angles. The performance of the algorithm is evaluated with respect to the operating point of the robot, the programmed tool velocity, and the design variables of the ILC algorithm. The chosen movements are intended to represent typical paths in a laser cutting application. Even though a fairly simple ILC algorithm is applied, the error reduction is substantial after only five iterations and the algorithm shows good robustness properties.

  • 25.
    Persson, Bengt
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Bioinformatics.
    Bioinformatics in Membrane Protein Analysis2006In: Structural Genomics on Membrane Proteins / [ed] Lundstrom, Kenneth H., Boca Raton: Taylor&Francis Group , 2006, -400 p.Chapter in book (Other academic)
    Abstract [en]

    While the genomic revolution has quickly led to the deposit of  more than 30,000 structures in the protein data bank (PDB), less than one percent of those contributions represent membrane proteins despite the fact that membrane proteins constitute some 20 percent of all proteins. This discrepancy becomes significantly troublesome when it is coupled with the fact that 60 percent of current drugs are based on targeting this group of proteins, a trend that does not seem likely to reverse.

    Structural Genomics on Membrane Proteinsprovides an excellent overview on novel research in bioinformatics and modeling on membranes, as well as the latest technological developments being employed in expression, purification, and crystallography to obtain high-resolution structures on membrane proteins. This cutting-edge work also explains the difficulties facing researchers—both technical and ethical—that have slowed the process. 

    Structural Genomics on Membrane Proteins provides researchers with an unprecedented look at the novel technologies that will ultimately allow them to conquer the last frontier in structural biology, leading to accelerated breakthroughs in drug discovery.

  • 26.
    Lenner, Matz
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Production Engineering.
    Better Workmanship Reduces Hazardous Cutting1999In: IWMS14,1999, 1999Conference paper (Other academic)
  • 27.
    Wittesjö, Viktor
    et al.
    Linköping University, Department of Management and Engineering, Production Economics .
    Thörne, Joakim
    Linköping University, Department of Management and Engineering, Production Economics .
    Vidareutveckling av skrotfallsprognos: på Sapa Heat Transfer AB2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Sapa Heat Transfer AB (SHT AB) is one of three components in the corporate group Sapa Group, owned by the Norwegian company Orkla ASA. Sapa Heat Transfer AB has production in Sweden (Finspång) and China (Shanghai). The company is a world leading supplier and developer of aluminum strips used in various types of heat exchangers, primarily in the automotive industry.

    In several stages of the production, which includes remelting, hot and cold milling and cutting, a part of the processed material becomes scrap metal. This scrap metal is collected and reused as raw material in the remelting factory. SHT AB currently has no automated IT support to forecasting this scrap metal; these calculations are, in the current situation, made with the help of Excel. In the calculation of scrap metal the company uses a standard value, corresponding to the average yield for all alloy combinations in the production. As a mean value is being used for all alloy combinations, the forecast becomes misleading for some alloys. The yield varies widely depending on the alloy, which means there are alloy combinations that are above the average yield and some that are below. In the current situation SHT AB has no link between actual orders and the short-term forecast of scrap metal.

    The purpose of this thesis is to develop proposals on how Sapa Heat Transfer AB can and should develop its forecasting of scrap metal. This will help them getting a better accuracy in their forecasting and thereby improving the raw material planning.

    In order to improve the long-term forecast of scrap metal the decomposition of the forecast for the alloy combination had to be analyzed. An improvement of the decomposition will mean an improvement of the precision for the long-term prognosis of scrap metal. A change in the decomposition will also influence the capacity planning in the remelting factory.

    The action proposal for the long-term forecasting will result in a better accuracy of the forecast by replacing the mean value for the yield by a specific forecasted yield of each alloy combination. The data needed to carry through such a forecast is available in SHT AB´s databases, and by using the forecasting method exponential smoothing the yield can be forecasted. By using this method a forecast will be obtained that, with a low value of α, will not take such great impact from extreme values that sometimes occur.

    The current short-term scrap metal forecast, based on a decomposition of the alloy combination forecast, can be improved by a link to the actual backlog. If this link is established the scrap metal forecast will be based on known information instead of forecasted data. A link to the backlog can only be used for a short-term forecast due to the length of the awaiting orders.

    The action proposal to improve the short-term forecast assumes that a standardized forecast is developed for the scrap groups to be projected. The forecast should use an individually forecasted scrap factor produced with exponential smoothing for each scrap group. The scrap factor is based on historical data for the material planned to go into the process and the weighed scrap delivered to the remelting factory. With this scrap factor, data on how much material that is planned into the process the coming weeks and with consideration of scrap falling throughout the lead time the expected amount of scrap for the coming week / weeks can be calculated.

    To get a better precision compared to the standardized forecasts, the forecasts of the most interesting scrap groups should be developed and adapted. They can be given individual values of the smoothing constant α for the prediction of the scrap factor and the way the lead time is being considered can be adjusted. In the proposal the simplification that scrap is expected to fall symmetrically distributed over the lead time has been done. In reality this is not the case. Therefore, the forecast should also be developed to take into account that, for example, more scrap is falling in the end of the lead time.

  • 28.
    Ringkvist, Hans
    Linköping University, Department of Management and Engineering, Production Engineering .
    Kartläggning av tillverkningsflöden: Ett förbättringsarbete på CH Industry i Eskilstuna2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This bachelor thesis has been conducted at the Department of Management and Engineering, IEI, at the University of Linköping, for CH Industry in Eskilstuna. The purpose of this report is to map the most crucial products of the company by identifying the value stream and measuring the capacity utilisation for relevant machines. The report is limited to the analysis of the production flow of a total of 40 products. The most significant products for CH Industry are analysed by means of a value stream map for identification of the production process, the information flow and times in stockpiles.   

    The report is divided into six parts. The first half of the report describes the corporate enterprise of CH Industry, presents the theory behind the concept and also explains the methods used in the report. The second half describes how the analyses were carried out and the results are presented.  The final chapter contains a conclusion followed by a discussion.

    The report results in an extensive Excel document where the value stream is mapped and information about operation times, changeovers and capacity utilisation for the machine resources are identified. The mapping of the value stream reveals machine resources that from both a material flow and a transporting perspective are misplaced. Large sections of the details flow from blast resource 20 to milling machine recourse 57 and after that to the final inventory of goods. To the blast resource 20, more than half of the processed details come from the resource group ”Ämne” (laser cutter, stamping machine and cut-off saw).

    Strategically moving blast resource 20 and milling recourse 57 closer to each other would reduce transport distances, storage and lead times. The area where the old laser-cutting park was located would be suitable for this purpose.

    The pillar drills in the multi-operation resource 56 could be rearranged to a manual welding group and a manual bending press group. The operators for these resource groups could then do the broaching or drilling operation for smaller quantities before the actual bending or welding operation. This would eliminate stockpiles before and after the multi-operation resource and would reduce transport distances. 

    The value stream map indicates that the analysed article is overproduced. The article is manufactured in big quantities, which leads to long time in stockpiles and unnecessary handling. By manufacturing the article on customer’s demand lead times and capital tied up in stockpiles could be reduced.

  • 29.
    Henriksson, Robert
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, Department of Electrical Engineering.
    Observatörer för skattning av verktygspositionen hos en industrirobot: Design, simulering och experimentell verifiering2009Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis approaches the problem of estimating the arm angles of an industrial robot with flexibilities in joints and links. Due to cost-cutting efforts in the industrial robots industry, weaker components and more cost-effective structures have been introduced which in turn has led to problems with flexibilities, nonlinearities and friction. In order to handle these challenging dynamic problems and achieve high accuracy this study introduces state observers to estimate the tool position.The observers use measurements of the motor angles and an accelerometer and the different evaluated observers are based on an Extended Kalman Filter and a deterministic variant. They have been evaluated in experiments on an industrial robot with two degrees of freedom. The experimental verification shows that the state estimates can be highly accurate for medium frequency motions, ranging from 3-30Hz. For this interval the estimate were also robust to model inaccuracies.The estimation of low-frequency motions was relatively poor, due to problemswith drift for the accelerometer, and it also showed a significant dependence on the accuracy of the model. For industrial robots it is mainly the medium frequency motions which are hard to estimate with existing techniques and these observers therefore carries great potential for increased precision.

  • 30.
    Ulrich, Christian
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Louthander, Dan
    Senset AB, Universitetsvägen 14, SE-583 30 Linköping, Sweden.
    Mårtensson, Per
    Senset AB, Universitetsvägen 14, SE-583 30 Linköping, Sweden.
    Kluftinger, André
    WIKA Alexander Wiegand GmbH & Co. KG, Alexander-Wiegand-Strasse, 63911 Klingenberg, Germany.
    Gawronski, Michael
    WIKA Alexander Wiegand GmbH & Co. KG, Alexander-Wiegand-Strasse, 63911 Klingenberg, Germany.
    Björefors, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Evaluation of industrial cutting fluids using electrochemical impedance spectroscopy and multivariate data analysis2012In: Talanta: The International Journal of Pure and Applied Analytical Chemistry, ISSN 0039-9140, E-ISSN 1873-3573, Vol. 97, 468-472 p.Article in journal (Refereed)
    Abstract [en]

    In this paper, we explore the combination of electrochemical impedance spectroscopy (EIS) and multivariate data analysis to evaluate the concentration and pH of an industrial cutting fluid. These parameters are vital for the performance of for instance tooling processes, and an on-line monitoring system would be very beneficial. It is shown that both the total impedance and the phase angle contain information that allows the simultaneous discrimination of the concentration and the pH. The final evaluation was made with a regression model, namely partial least squares (PLS). This approach provided a way to quickly and simply find the correlation between EIS data and the sought parameters. The results from the measurements showed the possibility to predict the concentration and pH level, indicating the potential of this method for on-line measurements.

  • 31.
    Norrlander, Jens
    et al.
    Linköping University, Department of Management and Economics.
    Andersson Anell, Per
    Linköping University, Department of Management and Economics.
    Can Micro Credits Contribute To Poverty Alleviation?: A study of female entrepreneurs in Vietnam.2001Independent thesis Advanced level (degree of Magister)Student thesis
    Abstract [en]

    Introduction: Poverty is today a global problem which is getting more and more attention. Organisations as UNDP, OECD and World Bank have a common target of cutting poverty in half by year 2015. But if this target is going to be feasible it is important to understand poverty. Nobel Prize winner Amartya Sen argues that standard of living should be expressed in quality of life not in terms of quantity of goods and other economic factors. Sen has developed theories concerning poverty that is commonly used in today debate. One way to diminish poverty is microfinance. Microfinance is small loans given to poor people as a way for them to start or develop a business of some kind. Microfinance programs often combine the loans with education and social activities. Aim: Investigate if microfinance can contribute to permanent poverty alleviation, develop a model and apply it in rural Vietnam. The following questions will help to achieve our aim: - How do microfinance effect poor women in rural Vietnam? - What happens if one applies Amartya Sen's theories of poverty in rural Vietnam?

    Results: Microfinance is a good tool in the struggle to diminishing poverty. We found many examples where microfinance had improved the women’s life in different areas. But to make the microfinance even more effective it is important it is effective education and right members participating. Under ideal circumstances the process of microfinance work as in the NORAN-model, however in reality it is not so easy. But if you are aware of the problems and try to avoid them, microfinance can help many women. Thus our conclusion is that microfinance certainly can and already do contribute to permanent poverty alleviation.

  • 32.
    Nyström, Daniel
    et al.
    Linköping University, Department of Mechanical Engineering.
    Walfridsson, Lars
    Linköping University, Department of Mechanical Engineering.
    Säkerhetsbrytare för Gräsklippare2007Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    This thesis describes teh solution of two problems regarding safety on powered lawnmowers; protectning the users from injury when using the lawnmower in slopes, and when cleaning the cutting blade.

    The task was carried out through initial studies on a representative lawnmower. A generation of ideas followed with an evaluation to select the best solution. The winning concept was further developed to reach acceptable performance. The word resulted in a functioning prototype utilising an original way of detecting inclinations without incorrect signals. It c an serve as a platform for further development into a product.

    The work gives insightful experience of solving real-world problems, and especially to deal with situations where several variables and their effects are unknown

    Please note that several parts of the work are confidential, and have therefore been removed from the thesis.

  • 33.
    Skoglund, Björn
    Linköping University, Department of Electrical Engineering.
    Code profiling as a design tool for application specific instruction sets2007Independent thesis Basic level (professional degree), 20 points / 30 hpStudent thesis
    Abstract [en]

    As the embedded devices has become more and more generalized and as their product cycles keeps shrinking the field has opened up for the Application Specific Instruction set Processor. A mix between the classic generalized microcontroller and the specialized ASIC the ASIP keeps a set of general processing instructions for executing embedded software but combines that with a set of heavily specialized instructions for speeding up the data intense application core algorithms. One important aspect of the ASIP design flow

    research is cutting design time and cost. One way of that is automation of the instruction set design. In order to do so a process is needed where the algorithm to be ASIPed is analyzed and critical operations are found and exposed so that they can be implemented in special hardware. This process is called profiling. This thesis describes an implementation of a fine grained source code profiler for use in an ASIP design flow. The profiler software is based on a static-dynamic workflow where data is assembled from both static

    analysis and dynamic execution of the program and then analyzed together in an specially made analysis software.

  • 34.
    Athari, Emad
    et al.
    Linköping University, Department of Electrical Engineering.
    Lerenius, Petter
    Linköping University, Department of Electrical Engineering.
    Design and implementation of an SDR receiver for the VHF band2007Independent thesis Basic level (professional degree), 20 points / 30 hpStudent thesis
    Abstract [en]

    The purpose of this thesis work is to examine the possibility of building a software-defined radio (SDR) for the VHF-band. The goal is to accomplish this with as few components as possible, thus cutting down the size and the production cost.

    An SDR solution means that the sampling of the signal is done as close to the antenna as possible. The wide bandwidth needed in such a product is achieved by using SP Devices algorithm for time-interleaved ADCs. Two hardware prototypes and two versions of the software were designed and implemented using this technology.

    They were also analyzed within this thesis work. The results proved to be good, and the possibilities to produce a commercial software-defined radio receiver for the VHF-band are good.

  • 35.
    Hansson, Henrik
    Linköping University, Department of Computer and Information Science.
    Craft Physics Interface2007Independent thesis Basic level (professional degree), 20 points / 30 hpStudent thesis
    Abstract [en]

    This is a masters thesis (20p) in computer science at the University of Linköping. This thesis will give an introduction to what a physics engine is and what it consist of. It will put some engines under the magnifying glass and test them in a couple of runtime tests. Two cutting edge commercial physics engines have been examined, trying to predict the future of physics engines. From the research and test results, an interface for physics engine independency has been implemented for a company called Craft Animations in Gothenburg, Sweden.

  • 36.
    Eriksson, Linda
    et al.
    Linköping University, Department of Production Economics.
    Gustafsson, Mikael
    Linköping University, Department of Production Economics.
    Lappning eller kuggslipning: Av kronhjul och pinjonger på Scanias transmissionsavdelning2006Independent thesis Basic level (professional degree), 20 points / 30 hpStudent thesis
    Abstract [en]

    This thesis is accomplished in the transmission department, DX, on Scania, Södertälje. The purpose is to compare the method lapping, that are used today, with the method grinding. The two methods are used for hard surfacing on bevel gears, one of the components in the transmission for trucks and busses. The methods are compared with a widely perspective and constructions, production, logistic and economy are taken in to considerations.

    Scania has experienced some problems with the lapping process and that’s why they want this pre-study done. In the lapping process the material removal occurs when the flanks of the wheel and pinion touches, this makes it necessary to synchronise the production flow for wheel and pinion before the machining. This cause loses in efficiency and makes it difficult to plan the production. With grinding the removal of material is carried out by a grinding wheel that separate the production and planning for the wheel and pinion. Lapping has also a very limited capacity in removal of material. With grinding it is possible to remove more materials, up to five times.

    During the study even more problem with lapping occurs. The method can’t guarantee a stable quality and automatization of the hard surfacing of the gear is not possible with lapping. Grinding on the other hand guarantee constant quality and creates opportunities for automatization. Grinding solves a lot of the problems that appears today but it also has other advantages. More complex forms on the flank can be created with grinding then with lapping, making opportunities for the construction department. By using modification of the flank form the gear can evolving in both load carrying capacity and noise behaviour.

    There are also risks with grinding. This report identifies several and burnings are one of them. Burning appears when the temperature between the flank and the grinding wheel get to high. This causes damage on the flank surface. Another risk has to do with the heat treatment. Because of the higher removal of material with grinding, it is necessary to leave more material on the flank in the cutting. The consequence could be that a longer time is required in the furnace to get the same depth of case.

    Even more indirect effects of a change in method are observed in the report. By using grinding, potential for cutting with a higher speed appears which leads to reduction in cycle time. In the hard turning machine, where the wheels are machined, the cycle time will increase.

    The conclusion of the report is, with respect to the purpose, that Scania should grind all their bevel gears. The strongest argument is the potential in separating the production system for wheel and pinion, the increased performance of the bevel gear and the constant quality that grinding achieves.

  • 37.
    Ragnarsson, Tobias
    Linköping University, Department of Mechanical Engineering.
    Reglerbara skovlar på pumphjul2006Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    The thesis investigates if it is possible to replace several pumpimpellers with one controllable pumpimpeller, with a economical and a manufacturing analisys aspect. The studied pumpimpeller is mounted on a midrange wastewaterpump, N3127MT.

    In the thesis a contemplated manufacturing process is evaluated for a concept that are supposed to act as a controllable pumpimpeller. The pumpimpeller are studied in a manufacturing and flow matter and are presented in the thesis.

    The manufacturing cost is also estimated, and this has been compared to the storage cost and other costs that the existing pumpimpeller generates.

    The thesis also shows that the concept has minor losses in cutting quality aswell as the effiency comparing to the existing pumpimpeller.

    The concept also raises the manufacturing cost and this increasing cost makes the presented concept to expensive to carry through.

    An investigation of the costs that the existing pumpimpeller produces has also been done, and this shows that there is not that much expenses to earn regarding to for example the storage cost. The storage cost includes information from Flygt’s central storagecenter in Lindas, Sweden and Metz, France, and also an inventory about the pumpimpellers located at Flygt’s different distributors worldwide.

    The thesis shows that a controllable pumpimpeller will generally increase the cost for the pumpimpeller and the performance of the pumpimpeller will decrease.

  • 38.
    Hartleb, Carina
    Linköping University, Department of Biomedical Engineering.
    Creation and Evaluation of Solid Optical Tissue Phantoms for Bio-Medical Optics Applications2005Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Because of their compatibility and precise results bio-optical methods based on measurements of the optical tissue properties gain importance in non-invasive medical therapy and diagnostic. For development and standardization of medical devices optical phantoms are suitable. The present report handles the creation and evaluation of solid tissue phantoms, made up of Agar, Vasolipid and ink utilizing different mixture ratios. After cutting the models in slices of 0.2 to 1.1 mm thickness the absorption- and scattering coefficient were measured using a collimated laser beam setup. As result of the study a formula for the preparation of solid optical tissue phantoms with desired optical properties was found, that is valid for models containing 1.12 % Agar.

  • 39.
    Haglund, Johan
    et al.
    Linköping University, Department of Management and Engineering.
    Gustafsson, Joel
    Linköping University, Department of Management and Engineering.
    Förslag till ombyggnation av klipp- och bockningsmaskin2008Independent thesis Basic level (university diploma), 10 points / 15 hpStudent thesis
    Abstract [en]

    This thesis work has been performed on request by SWT (Scandinavia WeldTech AB). SWT manufactures, develop and sell ready to assemble building systems for concrete rafter beam applications. The beams in this system consist of a u-beam that is welded to a flange. To be able to fill the beams with concrete there is holes in the beams top end. The holes are made in a “punching machine”.  These holes are cut out and the remaining steel piece is bent down in the u-beam. The problem today is that the machine only can make holes in beams with a height up to 340 mm. Now SWT wants a machine that can handle beams up to 500 mm high.

    Our task in this work was to make a feasibility study on what needs to be done to rebuild the machine. Besides the demand with higher beams we also looked at things to improve. Another task was to investigate the needs for cutting in beams made by thicker steel plates.

    In this work we used some of the theories described by David G. Ullman for the concept generation and evaluation. When generating the concepts we choose to make a concept of each subpart of the machine. Then we put the winning concepts together to form a final solution for the whole machine. When looking at the wear on the tools we could see that much could be done by making the control of the cutting column easier when adjusting the tool. To see what demands there were for cutting in thicker plates we had to come up with a theory for calculation off cutting and bending. Then we had to compare our theory with the reality, and that was done by measuring the pressure on the working cylinder when the machine was operating. Those results showed that our theory was working for 5 mm thickness but not for 4 mm thickness. There is however some uncertainness that makes our measured results not quite reliable for 4 mm steel.

    When it comes to the demand to manage higher beams we came to the conclusion that the best alternative is to manufacture a new frame. This is also suggested for the plates in the feeding unit. But we recommend that the existing cylinders and roof is used.

    For the problem on how to make the tool adjustments easier we came up with two solutions. The alternative with manual adjusting and assembly demands a reconstruction of the hydraulic system so that its functions meets the demands that are needed to realize the proposed solution. The advantage with this proposition is that the operator always has the possibility to affect the position of the tools so that the right cutting column is received. Our other suggestion is to install permanent steering guiding so the lower die gets in right position when mounting it. This proposal does not mean any bigger reconstruction but it does not make it possible to adjust the position of the cutting tool. To work proper both our solutions demands that the lower dies is modified.

    To make the mounting of the upper die easier we came up with two solutions that in short terms means that the die is held up before mounting. This means that the operator can have both his hands free when tighten the bolts.

    If thicker plate should be cut it will lead to large reconstructions of the hydraulic system with new cylinders and more. This due to the maximum pressing force that the machine is capable of is too small. But for a small change in thickness it might be enough to lower the force by reducing the friction in terms of better lubrication and modified tools.

  • 40.
    Marques Novo, Francisco José
    et al.
    Linköping University, Department of Mechanical Engineering.
    Saraiva Rézio, Henrique Manuel
    Linköping University, Department of Mechanical Engineering.
    FE safety analysis of a high speed wood planer cutter. An alternative method to achieve the requirements of EN847 standard2004Independent thesis Basic level (professional degree)Student thesis
    Abstract [en]

    In the last decades, high speed cutting has become an attractive technology in the wood industry. The possibility of reducing global costs in addiction with an increase in productivity, were the main reasons for the enlargement of the use of this technology.

    As usual, these advantages are accompanied by disadvantages that should be carefully analyzed. If on the one hand cutting forces are reduced with increasing cutting speeds, on the other hand, the centrifugal forces affecting the tool are higher. Exposed to such high loads, there is a considerable risk of tool failure that embeds hazards for both machine and workers.

    To prevent the risk of accidents and to guarantee safety in use, security standards have been implemented in industrial fields, imposing specific experimental tests, with defined procedure modes. Accordingly with these standards, the results obtained through the tests should fall inside limited ranges. The experimental tests suggested on the European Standards are intended to simulate the real working conditions of a rotating cutting tool, where extreme centrifugal forces are imposed by the high values of speed. Although their main importance, these destructive tests aren’t always practicable. It happens, for instance, with tools produced in small batch sizes, or as an ascertainment for the fail-critical speed during the development stage, or even due to physical incompatibilities between the tool and the laboratory testmachines.

    The high value of weight associated with the cutting tool prototype developed and patented by Verktygs Larsson AB was an impediment to run the laboratorial tests specified by the standards, forcing the company to find a new way to assure the safety requirements of their product.

    The main goal of this project was the development of an alternative method based on finite element theory to perform a safety analysis to the prototype of a wood cutter. This tool is used as a component in high speed planers.

    In addiction to this primary objective, some considerations were made about other available models, with increased dimensions or even with different parameters. If there was the need, design changes could be assumed in order to guarantee that the tool reached the requisites of the safety standards. Considering an optimization effort, material changes would also be considered, to aim in the direction of reducing the tool weight and the consequent centrifugal forces.

  • 41.
    Lifvergren-Kaya, Marie
    Linköping University, Department of Thematic Studies.
    Avverkning av nyckelbiotoper: en studie av den teoretiska begreppsdefinitionen och den praktiska hanteringen av nyckelbiotoper2003Independent thesis Advanced level (degree of Magister)Student thesis
    Abstract [sv]

    Detta är en studie av de teoretiska riktlinjerna kring begrepsdefinitionen nyckelbiotop samt den praktiska hanteringen av nyckelbiotoper i skogregionerna Östra Götaland, Dalarna/Gävleborg och Örebro/Värmland. Syftet med studien är att undersöka orsakerna till att nyckelbiotoper avverkas idag. Fokus ligger på om det finns en skillnad mellan den teoretiska begreppsdefinitionen och den praktiska hanteringen av nyckelbiotoper. Undersökningen genomfördes genom enkätfrågor och intervjufrågor till respondenter inom skogsbolag, skogsägarföreningar, stift (skogsbruken) och Skogsvårdsstyrelsen. De övergripande frågeställningarna var om det finns avvikelser mellan beslut och handling i hanteringen av nyckelbiotoper och om definitionen av nyckelbiotoper är förankrad, relevant och fungerande hos dem som planerar och avverkar inom skogssektorn. Enkät - och intervjusvaren från denna studie visar att både skogsbruken och Skogsvårdsstyrelserna anser att definitionen av nyckelbiotoper är förankrad hos dem som planerar och avverkar. Orsakerna till att det avverkas nyckelbiotoper är enligt Skogsvårdsstyrelserna att avverkningarna beror på ekonomiska faktorer vilket inte överensstämmer med skogsbrukens svar. Skogsstyrelsen menade att informationsbrist kunde vara en tänkbar orsak medan skogsbruken var delade i sin synpunkt på denna orsak. Angående definitionens relevans och fungerande i praktiken svarade Skogsvårdstyrelsen övervägande att de tyckte den var fungerande och i skogsbruken var meningarna delade om denna fråga. Av svaren framkom att den teoretiska begreppsdefinitionen ifrågasätts av främst skogsbruken men också av Skogsvårdsstyrelsen då den bland annat är så starkt kopplad till rödlistade arter. Studien visar att det finns mycket som kan och bör åtgärdas i problematiken kring avverkning av nyckelbiotoper och dess orsaker. Det är positivt att studien också visar att samtliga inom skogsbruken samt Skogsvårdsstyrelsens personal anser sig ha möjlighet att påverka inom sin organisation för att förhindra att avverkning av nyckelbiotoper sker i framtiden.

  • 42.
    Carlsson, Magnus
    et al.
    Linköping University, Department of Mechanical Engineering.
    Kristoffersson, Daniel
    Linköping University, Department of Mechanical Engineering.
    Automatiskt avvägningssystem för obemannad undervattensfarkost2005Independent thesis Basic level (professional degree)Student thesis
    Abstract [en]

    This master thesis work was done at Saab Underwater Systems AB, a company at the cutting edge of underwater technology. Here torpedoes and other underwater vehicles are developed and manufactured. The major customers are navies of different countries, mostly the Swedish navy.

    The aim of this master thesis is to develop, construct and evaluate an automatic Trim System for Unmanned Underwater Vehicles. The task of the system is to change the position of the centre of mass and the vehicle’s total mass or volume. A system like this gives more opportunities like improved low speed properties, manoeuvre ability and energy consumption.

    Different ways to make this change of total mass and position of centre of mass has been discussed and a choice has been done. A system of chosen concept has then been developed, constructed and evaluated. A part of big importance in this report is the work with simulations to predict the performance of the system and its behaviour. Other big parts has been to find suiting components and to develop the control electronics of the system.

  • 43.
    Borg, Niklas
    Linköping University, Department of Electrical Engineering.
    Reglering av matarsystem vid höghastighetskapning2002Independent thesis Basic level (professional degree)Student thesis
    Abstract [en]

    Today small metal parts are mass-produced as for example rollers in cylinder bearings. At high velocity cutting the metal is cut with a great force in a scissor-like device. Both precision and repeatability is important to be able to guarantee good quality, but from an economical point of view it is also important to keep a great manufacturing capacity. The part of the process that is most time consuming is when the metal bar, that is about to be cut, is fed to the right position. Therefore it is interesting to examine if the time used for positioning can be reduced. This thesis examines if more advanced automatic control can be used to speed up the process while maintaining the precision. In order to test and evaluate different theories, two different mathematical models have been developed. The models where implemented in the simulation program SIMULINK in MATLAB and they where compared to and adapted to data measured on the physical machine. One model is developed from physical relationships and mostly used for simulations while the other one, a condition state model, has been used for regulator design. The first question to answer was if it is at all possible to control the process any faster. When a theoretical limit was found the next step was to design a regulator to show that the theory of automatic control does not imply too great limitations. The design that was chosen was condition state feedback where the states were appraised with an observer.

    A faster system will raise the demands on cycle times and precision. To make sure that the hardware isn’t the limiting factor, design requirements have been set up. A small list of what hardware is available has also been put together (and shows that it is possible to implement such a system).

    The conclusion is that it is, theoretically, possible to radically increase the manufacturing capacity. The assumptions for this to be accomplished is especially that the uncertainty of the model is minimizedand that hardware with enough capacity can be found.

  • 44.
    Fredriksson, Maria
    Linköping University, The Tema Institute.
    Organic chlorine in soilwater: Influence of Clear-cuttning and Nitrogen2007Independent thesis Basic level (degree of Bachelor), 10 points / 15 hpStudent thesis
    Abstract [en]

    Chlorine is one of most common element on earth and it is essential in every living organism, but can also cause problems in the environment. Chlorine can exist both as inorganic (Clin) and organically bound (Clorg). Earlier was the common opinion that Clorg only occurs from anthropogenic sources, but the last years, research has shown that chlorine is a part of the biogeochemical cycle and Clorg also can have natural sources. Many chlorinated substances are poisonous, so the fact that they have a natural source created attention. Fertilizations with nitrogen in forest areas have shown unexpected consequences, such as an increase leakage of nitrogen to ground and surface water. Clear-cutting is a disturbance on the ecosystem and the environment is sensitive for disturbances. Because of the fact that both chlorine and fertilization can be environmental problems and that clear-cutting is a big disturbance in the nature, this study will investigate if there are changes of organic chlorine (Clorg) in soil water after clear-cutting and if fertilization with nitrogen has any influence on the concentration of Clorg. This study was made in a forest area in Värmland, Sweden (Hagfors). Chemical analyses were made in the laboratory though measuring AOX (absorbable organic halogens). The result of this study showed that clear-cutting probably has some effect on the Clorg concentration and that nitrogen doesn’t have any influence.

  • 45.
    Greek, Julia
    Linköping University, Department of Management and Engineering, Carl Malmsten - furniture studies.
    Komplexa parkettläggningar: Undersökning av metoder för repetitiva parkettläggningar2016Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    This bachelor’s thesis begins in the journeyman piece I made during my third and final year at Carl Malmsten Furniture Studies. I examine different methods that can be used to produce a complex parquet installation. And how do the methods compare when it comes to time consumption, cost, material consumption and aesthetic expression?

    Practically, I examine three methods: CNC milling, laser cutting and hand held milling.

    The goal of my thesis is to develop useful knowledge which provides guidance for the production of complex parquet installations.

    The result is in addition to experience and knowledge, swatches of the techniques I investigated, and products that show how you can use parquet installations in practice.

    Laser cutting provides the most consistent results, and is most rational to manufacture, despite a high investment cost.

  • 46.
    Abbatelli, Daniele
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Material flows in the waterjet industry: an environmental perspective2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Abrasive Waterjet cutting (AWJ) presents many advantages over competing machining techniques, but several issues are related to the high volume of materials (and in particular of abrasive) used in the process.

    In this study, the environmental impact of the material flows in the abrasive waterjet industry has been analyzed adopting a life cycle perspective in order to individuate which phases place the largest burden on the environment. Moreover, three alternative abrasives (crushed rock, recycled glass and synthetic abrasive) and three disposal practices (in-site recycling, off-site recycling and recycling as construction material) have been also evaluated to estimate the benefits that can be achieved if these could be used in place of garnet abrasives and landfilling.

    The transportation of the abrasive resulted to be the phase that has the largest influence in every case and thus should be reduced as much as possible. For what concerns the alternative options, the usage of recycled glass and the in-site recycling of the abrasive were the two alternatives with the best environmental performances. However, crushed rock could be the best option for what concerns the global warming potential if carbon sequestration due to carbonation of silicate rocks is taken into account. Off-site recycling and recycling as construction material are good options only if the transportation to the recycling site can be reduced. Synthetic abrasive are instead found to have a much larger impact compared to every other alternative examined.

  • 47.
    Sjölin, Victor
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, Faculty of Arts and Sciences.
    The effect of target fascination on control and situation awareness in a multiple remote tower center: A human factors study2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Multiple Remote Tower Center concept (mRTC) is a cutting edge project which allows one air traffic control officer (ATCO) to be in charge of multiple remotely situated airports simultaneously. When implemented, it will revolutionise how air traffic is managed at smaller airports and allow for increased efficiency and decreased operational costs. Consequently, at the time of writing a lot of effort is going into evaluating this new way of air traffic management from a safety perspective.

    Air traffic management has been defined as an issue maintaining situational awareness and exercising control. This thesis aims to investigate how the phenomenon target fascination affects the ATCOs ability to exercise control over its controlled airspace and maintain its situation awareness. It does so by creating a baseline scenario of work in a mRTC, and then comparing the ATCOs performance in the baseline scenario with its performance in the same corresponding scenario, but with elements of target fascination introduced. The differences in the scenarios are analysed using the Contextual Control Model, the Extended Control Model and a holistic framework for studying situation awareness.

    The analysis shows that target fascination does affect the ATCOs ability to maintain control, but not radically so, and only for a short period of time. The target fascination forces the ATCO to rely on information in the immediate environment to a higher degree than during regular work, as opposed to making decisions based on a holistic understanding of the situation and high level goals. However, once the understanding of the situation have been re-established, the level of control quickly returns to normal levels.

    Situation awareness is thus a key concept in maintaining control. The situation awareness analysis show that target fascination affects situation awareness by causing the ATCOs understanding of the situation to become outdated without the ATCOs knowledge. Because of this, there may be developments in the situation that the ATCO is not aware of, which hinders it from acting as it normally would. In some cases an intervention from an external actor or element may be necessary to break the fascination and re-establish the ATCOs understanding for the situation. As soon as the fascination is broken, the ATCO quickly takes steps to re-establish its situation awareness and return to normal operations.

  • 48.
    Nilsson, Alexander
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Trapped in the forest: The longhorn beetle Tragosoma depsarium L. in south-east Sweden2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The rare and elusive wood-living beetle Tragosoma depsarium, once widespread all over Sweden, is associated with large, sun-exposed pine logs required for breeding. Due to modern forestry and fire suppression, this type of substrate has become so rare in the landscape that the beetles’ existence in Sweden is threatened. Recently, the female sex pheromone of this species was synthesised, providing a new method to monitor beetle populations using pheromone traps. Such a method was used in the current study to relate the presence-absence of T. depsarium with different landscape variables at different scales; 100, 500, 1000 and 2000 meters, respectively. The occurrence of T. depsarium in Östergötland County was associated with the amount of protected areas and clear-cuts at 500 and 1000 meters, respectively. Additionally, the amount of pine forest within 2000 m from the trap showed a weak, positive effect on the number of beetles. In the whole south-east boreo-nemoral zone of Sweden, a positive correlation between beetle occurrence and protected areas were found at 2000 m together with a negative correlation for volume pine wood within 100 m. Also, emergence holes on pine logs around each trap were strongly associated with beetle occurrences. To conclude, using pheromone traps were an easy way of detecting beetles. Although the number of caught T. depsarium varied greatly over time, the sampling period matched the flight period well. For long-term survival of this beetle, the forests must contain breeding substrates and be opened up through prescribed burning, selective cutting and active forestry.

  • 49.
    Ekström, Erik
    Linköping University, Department of Physics, Chemistry and Biology.
    Effect of texture and blasting pressure on residual stress and surface modifications in wet sand blasted α-Al2O3 coating2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Recently, wet sand blasting on coated cutting tool inserts has drawn interest to the tooling industry due to its positive effects on cutting performance and tool life. This performance boost has partly been attributed to the buildup of compressive residual stresses in the coating during the blasting process. However, the mechanism of forming residual stresses in ceramic coatings during sand blasting is not fully understood.

    This work utilize x-ray diffraction as the main tool to study the formation and relaxation of residual stresses after wet sand blasting and annealing on 001, 012 and 110 textured α-Al2O3 coatings. To minimize the influence of stress gradients in the samples, all stress measurements were set up with a fixed analysis depth of 2 µm. Sand blasting was made with an alumina based slurry at 2, 3.2 and 4 bar pressure and the anneal was done at temperatures from 400 to 1000 °C for 2 hours or more. The coating hardness was evaluated by nanoindentation. Finally, the activation energy for the relaxation of residual stresses was estimated using the Zener-Wert-Avrami function.

    The results reveal the highest compressive residual stress with up to -5.3 GPa for the 012 texture while the stresses for the 001 and 110 textures peaked at -3.1 and -2.0 GPa, respectively. Further, a hardness gradient was present after blasting of the 001 and 012 textured samples indicating a higher stress at the surface of the coating. The 110 textured sample is the most brittle resulting in flaking of the coating during sand blasting. The different deformation mechanisms are related to difference in active slip planes between coatings with different textures. Both the stress and hardness decreased after heat treatment and the activation energy for stress relaxation was found to be as 1.1 ± 0.3 eV, 1.9 ± 0.2 eV and 1.2 ± 0.1 eV for the 001, 012 and 110 textures, respectively.

  • 50.
    Ceco, Mima
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Evaluation and optimization of cation exchanging materials for life-span optimization of engine oil2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Requirements of high performing engine oil are today necessary since the development of new machinery with modern standardsis a cutting edge technology demanding highly optimized components. One way of increasing the lubricating properties of engineoil is through the addition of antioxidants. Antioxidants included in lubricants have a number of functions, one being buffering theinorganic acids sulphuric acid and nitric acid.A novel method expected to lower the hydrogen ion concentration in acidified engine oil was evaluated in this thesis. Thecapability of four different types of cation exchangers to serve as complements for buffering additives in heavy vehicle engineswas assessed. Two cation exchangers were weak and two were strong. The analysis techniques used to evaluate what effect thecation exchangers have on engine oil were standard test method ASTM D4739, for measurements of the total base number (TBN),and inductively coupled plasma – atomic emission spectroscopy (ICP-AES). With ASTM D4739 it was found that weak cationexchangers give positive results with respect to the ability to decrease the hydrogen ion concentration in acidified engine oil.However, after begin subjected to strong cation exchangers, ASTM D4739 indicated that the hydrogen ion concentration in theacidified engine oil remains the same or increases.With additional literature studies of a variety of cation exchangers currently on the market, further optimization of the cationexchanging material could likely be achieved. In addition, the preparation method used during the evaluation of the cationexchangers should be optimized to give more reliable results.

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