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  • 126651.
    Åstedt, Björn
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Design and Bridges.
    Analys av system bestående av skivor, kopplade skivor och ramar med språngvisa styvhetsförändringar i höga byggnader2004Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 126652.
    Åstrand, Erik
    et al.
    Volvo Construction Equipment AB.
    Stenberg, Thomas
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Jonsson, Bertil
    Volvo Construction Equipment AB.
    Barsoum, Zuheir
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Welding procedures for fatigue life improvement of the weld toe2016In: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 60, no 3, p. 573-580Article in journal (Refereed)
    Abstract [en]

    This paper presents the results of an experimental study of gas metal arc welded, GMAW, cruciform joints made of common construction steel S355. The hypothesis is that smooth undercuts in as welded conditions can give enhanced fatigue properties similarly as post treated welds. Undercuts are generally seen as a defect or imperfection. Welders try to avoid these and repair them when they occur, which result in increased production lead time. Post weld improvement methods i.e. grinding or high-frequency-impact treatment (HFMI) as fatigue-enhancing post-treatment methods enforce amongst other effects a certain smooth undercut-shaped groove in the treated weld toe region. The obtained shallower weld toe transition reduces the geometrical notch effect and increases fatigue strength. This paper presents a study whereas welded specimens with a weld toe geometry similar to what is obtained by weld toe grinding or HFMI-treatment, has been produced, fatigue tested and analyzed. The improvement of the fatigue strength is comparable to post-weld treated specimens. It has proven to be an efficient way to achieve high-quality welds without introducing any additional operations in production, thus enabling weight reduction using cost-effective methods.

  • 126653.
    Åstrand, Maria
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology.
    Studier av metoder som kan reducera utsläpp av vattenburet fosfor från Korsnäsverken2006Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This Master’s thesis has been written in cooperation with the paper mill Korsnäsverken,owned by Korsnäs AB, which is located in Gävle, Sweden. The aim of the project: On the basis of earlier received knowledge, from the currents in the external wastewatertreatment system at Korsnäsverken, propose suitable ways of reducing the emissions ofdissolved phosphorus to the recipient.

    Since emissions of the growth-regulating nutrient phosphorus from Korsnäsverken may cause eutrophication, in their recipient the Baltic Sea, the regional environmental court has decided that the paper mill must reduce their phosphorous emissions by half.

    The experiments performed during this thesis were focused on chemical reduction. The other reducing methods described have been examined by literature studies. The water dissolved phosphorous has, in an earlier Master’s thesis, been located to certain currents in the external wastewater treatment system of Korsnäsverken and was further examined in the experimentsof this thesis. The used water in the experiments was taken from the bleach pond (AVB) andthe end sedimentation pond (Sed.zon).

    The results, from chemical reducing experiments in Sed.zon, showed that Korsnäsverkencould probably meet the condition set by the regional environmental court and reduce the emissions of phosphorus with 50 %. (Red bars in figure 1.) It furthermore showed that chemical reduction with polymer alone in Sed.zon could probably also reduce phosphorus by50 %. In AVB the result of chemical reduction was positive, but not as efficient as that of Sed.zon.

  • 126654.
    Åstrand, Max
    KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control.
    Short-term Underground Mine Scheduling: Constraint Programming in an Industrial Application2018Licentiate thesis, monograph (Other academic)
    Abstract [en]

    The operational performance of an underground mine depends critically on how the production is scheduled. Increasingly advanced methods are used to create optimized long-term plans, and simultaneously the actual excavation is getting more and more automated. Therefore, the mapping of long-term goals into tasks by manual short-term scheduling is becoming a limiting segment in the optimization chain. In this thesis we study automating the short-term mine scheduling process, and thus contribute to an important missing piece in the pursuit of autonomous mining.

    First, we clarify the fleet scheduling problem and the surrounding context. Based on this knowledge, we propose a flow shop that models the mine scheduling problem. A flow shop is a general abstract process formulation that captures the key properties of a scheduling problem without going into specific details. We argue that several popular mining methods can be modeled as a rich variant of a k-stage hybrid flow shop, where the flow shop includes a mix of interruptible and uninterruptible tasks, after-lags, machine unavailabilities, and sharing of machines between stages.

    Then, we propose a Constraint Programming approach to schedule the underground production fleet. We formalize the problem and present a model that can be used to solve it. The model is implemented and evaluated on instances representative of medium-sized underground mines.

    After that, we introduce travel times of the mobile machines to the scheduling problem. This acknowledges that underground road networks can span several hundreds of kilometers. With this addition, the initially proposed Constraint Programming model struggles with scaling to larger instances. Therefore, we introduce a second model. The second model does not solve the interruptible scheduling problem directly; instead, it solves a related uninterruptible problem and transforms the solution back to the original time domain. This model is significantly faster, and can solve instances representative of large-sized mines even when including travel times.

    Lastly, we focus on finding high-quality schedules by introducing Large Neighborhood Search. To do this, we present a domain-specific neighborhood definition based on relaxing variables corresponding to certain work areas. Variants of this neighborhood are evaluated in Large Neighborhood Search and compared to using only restarts. All methods and models in this thesis are evaluated on instances generated from an operational underground mine.

     

     

  • 126655.
    Åstrand, Max
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control. ABB Corp Res, Control Optimizat & Analyt, Automat Solut, Vasteras, Sweden.
    Johansson, Mikael
    KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control.
    Greberg, J.
    Lulea Univ Technol, Dept Civil Environm & Nat Resources Engn, Div Min & Geotech Engn, Lulea, Sweden..
    Underground mine scheduling modelled as a flow shop: a review of relevant work and future challenges2018In: The Southern African Journal of Mining and Metallurgy, ISSN 2225-6253, E-ISSN 1543-9518, Vol. 118, no 12, p. 1265-1276Article, review/survey (Refereed)
    Abstract [en]

    Advanced planning and automation are increasingly important in modern mines. Sophisticated methods for long-term mine planning are often used, and the advent of autonomous machines makes the actual operation more predictable. However, the interface between these two timescales, i.e. the scheduling of the mobile production fleet, often limits the ability to operate mines at maximum profitability. We show how scheduling the production fleet in an underground mine can be modelled as a flow shop. A flow shop is a general abstract process formulation that captures the key properties of a scheduling problem without going into specific details. Thus, the flow shop enables mine scheduling to reap the benefits of scheduling research from other industries. We review recent results from the mining community and the flow shop community, and introduce scheduling methods used in these two fields. This work aims at providing value to researchers from the mining community who want to leverage their skill set, as well as to theoretical researchers by presenting the mining process as a potential application area. Lastly, we discuss the results, and outline some future challenges and opportunities facing the industry.

  • 126656.
    Åstrand, Max
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control. ABB Corp Res, Control Optimizat & Analyt, Automat Solut, Vasteras, Sweden..
    Johansson, Mikael
    KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control.
    Greberg, J.
    Lulea Univ Technol, Dept Civil Environm & Nat Resources Engn, Div Min & Geotech Engn, Lulea, Sweden..
    Underground mine scheduling modelled as a flow shop: a review of relevant work and future challenges2018In: The Southern African Journal of Mining and Metallurgy, ISSN 2225-6253, E-ISSN 1543-9518, Vol. 118, no 12, p. 1265-1276Article, review/survey (Refereed)
    Abstract [en]

    Advanced planning and automation are increasingly important in modern mines. Sophisticated methods for long-term mine planning are often used, and the advent of autonomous machines makes the actual operation more predictable. However, the interface between these two timescales, i.e. the scheduling of the mobile production fleet, often limits the ability to operate mines at maximum profitability. We show how scheduling the production fleet in an underground mine can be modelled as a flow shop. A flow shop is a general abstract process formulation that captures the key properties of a scheduling problem without going into specific details. Thus, the flow shop enables mine scheduling to reap the benefits of scheduling research from other industries. We review recent results from the mining community and the flow shop community, and introduce scheduling methods used in these two fields. This work aims at providing value to researchers from the mining community who want to leverage their skill set, as well as to theoretical researchers by presenting the mining process as a potential application area. Lastly, we discuss the results, and outline some future challenges and opportunities facing the industry.

  • 126657.
    Åstrand, Max
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control. ABB Corporate Research Center, Västerås, Sweden.
    Johansson, Mikael
    KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control.
    Zanarini, A.
    Fleet scheduling in underground mines using constraint programming2018In: 15th International Conference on Integration of Constraint Programming, Artificial Intelligence, and Operations Research, CPAIOR 2018, Springer, 2018, Vol. 10848, p. 605-613Conference paper (Refereed)
    Abstract [en]

    The profitability of an underground mine is greatly affected by the scheduling of the mobile production fleet. Today, most mine operations are scheduled manually, which is a tedious and error-prone activity. In this contribution, we present and formalize the underground mine scheduling problem, and propose a CP-based model for solving it. The model is evaluated on instances generated from real data. The results are promising and show a potential for further extensions.

  • 126658.
    Åstrand, Max
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control. ABB Corporate Research, Sweden.
    Saarinen, K.
    Sander-Tavallaey, S.
    Surrogate models for design and study of underground mine ventilation2018In: 22nd IEEE International Conference on Emerging Technologies and Factory Automation, ETFA 2017, Institute of Electrical and Electronics Engineers (IEEE), 2018, p. 1-8Conference paper (Refereed)
    Abstract [en]

    Ventilation is vital for the production in an underground mine. Therefore, it is important to have efficient and accurate design tools in order to ensure and optimize the airflows in the mine. There are several commercial software for airflow simulation based on first principles. However, the computational cost of simulation together with integrational obstacles when connecting simulation to control strategies limits the benefit of these tools. In this paper an approach utilizing surrogate models as a complementary design tool is presented. It is shown that using surrogate models one can with rather low computational expense evaluate and benchmark different control strategies. It is also shown that the models can be used for identifying possible bottlenecks in the system in advance. Moreover, the use of surrogate models transfer the simulation into a development-friendly environment (such as Matlab). A test case is used based on a real underground mine ventilation design. Two types of surrogate models are fitted to process data; multiple least squares regression and a Gaussian process model. Sensitivity analysis on the surrogate shows the potential of using surrogate models for identifying bottlenecks. Furthermore, the surrogate is used to benchmark two different control strategies for mine ventilation.

  • 126659.
    Åstrand, Mie
    KTH, School of Industrial Engineering and Management (ITM), Applied Mechanical Engineering (KTH Södertälje).
    Absorbera färdiglager i utleveransprocessen -En fallstudie2014Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
  • 126660.
    Åstrand, Mikael
    KTH, School of Biotechnology (BIO).
    Affinity ligand selection using the ABD scaffold for targeting tumor biomarkers Her2 and Her32011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 126661.
    Åstrand, Mikael
    KTH, School of Biotechnology (BIO), Protein Technology.
    Engineering strategies for ABD-derived affinity proteins for therapeutic and diagnostic applications2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Small stable protein domains are attractive scaffolds for engineering affinity proteins due to their high tolerance to mutagenesis without loosing structural integrity. The albuminbinding domain is a 5 kDa three-helix bundle derived from the bacterial receptor Protein G with low-nanomolar affinity to albumin. In this thesis, the albumin-binding domain is explored as a scaffold for engineering novel affinity proteins with the possible benefit of combining a prolonged serum half-life with specific targeting in a single small scaffold protein. Previously, a library was created by randomizing surface-exposed residues in order to engineer affinity to a new target antigen in addition to the inherent albumin affinity. Here, phage display selections were separately performed against the tumor antigens ERBB2 and ERBB3. The ERBB3 selection resulted in a panel of candidates that were found to have varying affinities to ERBB3 in the nanomolar range, while still retaining a high affinity to albumin. Further characterization concluded that the clones also competed for binding to ERBB3 with the natural activating ligand Heregulin. The selections against ERBB2 resulted in sub-nanomolar affinities to ERBB2 where the binding site was found to overlap with the antibody Trastuzumab. The binding sites on ABD to albumin and either target were found in both selections to be mutually exclusive, as increased concentrations of albumin reduced the level of binding to ERBB2 or ERBB3. An affinity-matured ERBB2 binder, denoted ADAPT6, which lacked affinity to albumin was evaluated as a radionuclide-labeled imaging tracer for diagnosing ERBB2-positive tumors. Biodistribution studies in mice showed a high renal uptake consistent with affinity proteins in the same size range and the injected ADAPT quickly localized to the implanted tumor. High contrast images could be generated and ERBB2-expressing tissue could be distinguished from normal tissue with high contrast, demonstrating the feasibility of the scaffold for use as diagnostic tool. In a fourth study, affinity maturation strategies using staphylococcal cell-surface display were evaluated by comparing two replicate selections and varying the stringency. A sub-nanomolar target concentration was concluded to be inappropriate for equilibrium selection as the resulting output was highly variable between replicates. In contrast, equilibrium sorting at higher concentrations followed by kinetic-focused off-rate selection resulted in high output overlap between attempts and a clear correlation between affinity and enrichment.

  • 126662.
    Åstrand, Mikael
    et al.
    KTH, School of Biotechnology (BIO), Protein Technology.
    Nilvebrant, Johan
    KTH, School of Biotechnology (BIO), Protein Technology. Centre for Cellular and Biomolecular Research, Donnelly Centre, University of Toronto, Toronto, ON, Canada.
    Björnmalm, Mattias
    KTH, School of Biotechnology (BIO), Protein Technology. Department of Chemical and Biomolecular Engineering, University of Melbourne, Parkville, VIC, Australia.
    Lindbo, Sarah
    KTH, School of Biotechnology (BIO), Protein Technology.
    Hober, Sophia
    KTH, School of Biotechnology (BIO), Protein Technology.
    Löfblom, John
    KTH, School of Biotechnology (BIO), Protein Technology.
    Investigating affinity-maturation strategies and reproducibility of fluorescence-activated cell sorting using a recombinant ADAPT library displayed on staphylococci2016In: Protein Engineering Design & Selection, ISSN 1741-0126, E-ISSN 1741-0134, Vol. 29, no 5, p. 187-195Article in journal (Refereed)
    Abstract [en]

    During the past decades, advances in protein engineering have resulted in the development of various in vitro selection techniques (e.g. phage display) to facilitate discovery of new and improved proteins. The methods are based on linkage between genotype and phenotype and are often performed in successive rounds of selection. Since the resulting output depends on the selection pressures used and the applied strategy, parameters in each round must be carefully considered. In addition, studies have reported biases that can cause enrichment of unwanted clones and/or low correlation between abundance in output and affinity. We have recently developed a selection method based on display of protein libraries on Staphylococcus carnosus and isolation of affinity proteins by fluorescence-activated cell sorting. Here, we compared duplicate selections for affinity maturation using equilibrium binding at different target concentrations and kinetic off-rate selection. The results showed that kinetic selection is efficient for isolation of high-affinity binders and that equilibrium selection at subnanomolar concentrations should be avoided. Furthermore, the reproducibility of the selection was high and a clear correlation was observed between enrichment and affinity. This work reports on the reproducibility of bacterial display in combination with FACS and provides insights into selection design to help guide the development of new affinity proteins.

  • 126663. Åström, Alexander
    et al.
    Izosimov, Viacheslav
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Mechatronics.
    Örsmark, Ola
    Efficient Software Tool Qualification for Automotive Safety-Critical Systems2011Conference paper (Other academic)
  • 126664.
    Åström, August
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Sten, Morgan
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Macro segregation in continuous cast HSLA steels: With correlation to impact toughness2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The report reviews macro segregations in continuous cast steels and possible correlations to impact toughness. The purpose of the thesis is to investigate centreline segregates and V-segregates to see which of them that affect impact toughness the most. Apart from a literature study, Charpy-V data was collected with permission from SSAB for two steel types, grade A and grade B, each with respective dominant segregation type. The collected data was yielded in three individual Charpy-V tests at different spots on the metal sheet, derived within a close area. The average value of these tests were used in statistical analysis to observe the spread of values in different heats of the two steels. Additionally, the specimens were etched and captured in cross-section. Results indicated that for the data of grade A, where centreline segregates were dominant, the spread of values was higher than for the data of grade B. The conclusion is that centreline segregations are worse in relation to impact toughness, since higher deviations translates to less predictable properties from a customers perspective.

  • 126665.
    Åström, Axel
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology.
    Täta tak: en guide till skadefria takpannetak2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    I undersökningar av byggnadsskador visar sig takskador vara ett av de vanligaste förekommande problemen. Taktäckning med takpannor är det vanligaste i det Svenska  byggbeståndet. Arbetet är utfört med en litteraturstudie, fallstudie av nio skaderapporter ifrån Anticimex samt sju dokumenterade rivningar av tak i mälardalen. Både i litteraturstudien och fallstudierna pekar på att genomföringarna och anslutningarna på takpannetaken är de mest skadedrabbade områdena. Brister i uppdrag av underlagspapp är i fallstudierna vanligt förekommande, och har i flera fall lett till byggnadsskador. Vid omläggning av tak sparas ofta gamla plåtdetaljer vilket är en trolig förklaringen till att uppdrag av underbeslag och papp blir bristfällig. Genomföringsmanschetter och andra prefabricerade lösningar för tätning av stosar rekommenderas. Läktskiktet skall hållas fritt från skräp för att motverka röta av läkten, frostskador av takpannor och att minska vindlasten av takpannorna.  För att ge tillräcklig ventilation av takpannorna bör ströläkten vara minst 25mm i höjd, anpassning till större läkt kan ske vid flackare taklutningar. Skräp och yrsnö motverkas vid användning av nockband och fågellist i takfoten. 

  • 126666. Åström Borinder, Carin
    et al.
    Aune, Ragnhild E.
    KTH, School of Industrial Engineering and Management (ITM).
    Seetharaman, Seshadri
    KTH, School of Industrial Engineering and Management (ITM).
    Thermodynamic Assessment of Rare Earths. I: Review of Thermodynamic Properties of Rare Earth Oxide Systems1991Report (Refereed)
  • 126667.
    Åström, Emil
    KTH, School of Information and Communication Technology (ICT).
    Task Scheduling in Distributed Systems: Model and prototype2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Distributed systems is a collection of entities that cooperate to solve a problem that otherwise a single entity would not be able to solve. The use of heavy algorithms has been growing and therefore have distributed computation systems arisen. To make the best use of a distributed computation system task allocation and task scheduling algorithms has been developed. Task allocation is the process of allocating tasks to the best suitable processors of the system while task scheduling is used to determine the execution order of tasks. In some cases task scheduling also incorporate allocation process. A task is the smallest entity that can be scheduled and can be a process or a thread. Tasks are often bunched together as jobs which can include an arbitrary number of tasks. In this thesis has a general model and prototype been created which can be used in a variety of distributed systems and handle a wide range of tasks which includes tasks with execution order and deadlines. The model has been created using the best methods examined during a literature study which include the use of batch sampling, late binding and fair scheduling. A bare bone prototype has been created from the model which includes some core functionality and has been tested in regards to throughput and how balanced load it is. The throughput tests showed that the model does not lose throughput when tasks with execution order is scheduled and the load test showed that the system is fairly balanced. An evaluation of the model has been performed which shows that it works well in distributed systems and can handle a variety of tasks. The prototype has been has been tested in a small test environment which shows that it works well in smaller environments with similar requirements.

  • 126668.
    Åström Fransson, Donny
    KTH, School of Information and Communication Technology (ICT), Electronic, Computer and Software Systems, ECS.
    Utilizing Multicore Processors with Streamed Data Parallel Applications for Mobile Platforms2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Performance has always been a major concern among computers and microprocessors. So have the qualities of the applications that are executed by these processors. When the multicore evolution began, programmers faced a shift in programming paradigms required to utilize the full potential of these processors. Now that the same evolution has reached the market of mobile devices, the developers focusing on mobile platforms are facing the same challenge.

    This thesis focuses on assessing some of the possible application quality gains that can be achieved by adopting parallel programming techniques for mobile platforms. In particular, throughput performance, low-latency performance and power consumption.

    A Proof of Concept application was developed to measure these specific qualities using a streamed data parallel approach. By adopting proper parallel programming techniques to utilize the multicore processor architecture, it was possible to achieve 90% better throughput performance or the same latency quality with 60% lower CPU frequency. Unfortunately, the power consumption could not be accurately measured using the available hardware.

  • 126669.
    Åström, Frida
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    How dose Human resource management contribute to the business performance: - A case study2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 126670.
    Åström, Hannes
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Förbättring av arbetsförhållande i skördare2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    AbstractThe working conditions in the harvester are not very good. The shifts are often long and possibility to change working posture is poor and the operator remains seated all the timed during the process of cutting the trees and driving the machine. The human body is made to be in movement, not still. Sedentary itself is bad on health and may in worse cases lead to a premature death. Seated posture has several negative impacts on the human body.Work intensity in the harvester is high and the cycles are short and repetitive. The same muscle fibers are therefore continuously strained and tend to be exhausted. The operator is under a lot of stress. Stress in combination with muscular load will make it more harmful.The cost for the operators work related disorders manifests itself in reduced production, not used machines as a result from sick leave and in cases with long-term sickness, recruitment and training costs. By improving the working conditions it’s possible to reduce these costs and at best eliminated them. It leads probably also to a higher productivity in healthy drivers.To improve the working conditions for the operator of the harvester a concept for the seat, armrest and steering controls have been developed. The concept offers more variation in work pattern and more working postures. The steering controls have new shapes and offer two different ways of steering the crane that activates different muscles. The seat could be raised so that the work could be done from a standing position. Standing gets the spine in its neutral curvature with low pressure on the intervertebral discs, it enables a deeper breathing and an improved bowel movement. Being able to switch between seated and standing position leads to a varied load on the body and it also increases the blood circulation which helps recovery. The seat could be turn into a divided saddle seat. Saddle seats offer a position that could be seen as a mix between standing and seated position. Then spine gets in its natural position as it does while standing. At the same time the legs could be relaxed and the bodyweight rests upon the seat bones. The difference between a divided saddle seat and an ordinary is that the pressures on the genitals are much lower with the divided. Also the genitals temperature gets lower.The developed concept has been modeled in CAD. A physical prototype of the steering controls have been made that could be connected to a simulator for evaluation.

  • 126671. Åström, J.A.
    et al.
    Carter, A.
    Hetherington, J.
    Ioakimidis, K.
    Lindahl, Erik
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Theoretical & Computational Biophysics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Mozdzynski, G.
    Nash, R. W.
    Schlatter, Philipp
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Signell, A.
    Westerholm, J.
    Preparing scientific application software for exascale computing2013In: Applied Parallel and Scientific Computing: 11th International Conference, PARA 2012, Helsinki, Finland, June 10-13, 2012, Revised Selected Papers / [ed] Pekka Manninen, Per Öster, Springer, 2013, p. 27-42Conference paper (Refereed)
    Abstract [en]

    Many of the most widely used scientifc application software of today were developed largely during a time when the typical amount of compute cores was calculated in tens or hundreds. Within a not too distant future the number of cores will be calculated in at least hundreds of thousands or even millions. A European collaboration group CRESTA has recently been working on a set of renowned scientific software to investigate and develop these codes towards the realm of exascale computing. The codes are ELMFIRE, GROMACS, IFS, HemeLB, NEK5000, and OpenFOAM. This paper contains a summary of the strategies for their development towards exascale and results achieved during the first year of the collaboration project.

  • 126672.
    Åström, Joachim
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment.
    Granberg, Mikael
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment.
    Khakee, Abdul
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment.
    Apple Pie-Spinach Metaphor: Shall e-Democracy make Participatory Planning More Wholesome?2011In: Planning Practice & Research, ISSN 0269-7459, Vol. 26, no 5, p. 571-586Article in journal (Refereed)
    Abstract [en]

    Despite claims that planners' attitude towards public participation has not always been enthusiastic, there have been genuine attempts to devolve powers through participation-although seldom with success. In this paper we discuss several major attempts to improve participation in Sweden including case studies of e-participation. Despite great expectations on information and communication technologies, Swedish experience indicates that the status quo between planners and people remains.

  • 126673.
    Åström, K.
    KTH, Superseded Departments.
    On relativistic dust grains and extensive air showers1977Report (Other academic)
  • 126674. Åström, K. J.
    et al.
    Johansson, Karl H.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Wang, Qing-Guo
    Design of decoupled PID controllers for MIMO systems2001In: Proceedings of the 2001 American Control Conference, IEEE , 2001, p. 2015-2020Conference paper (Refereed)
    Abstract [en]

    The design of PID controllers for systems with interacting loops is discussed. It is important to deal with the interaction at the lower-level loops, since supervisory control based on for instance MPC seldom has sufficient bandwidth. A new scheme based on modified scalar PID design and static decoupling is developed, where the frequency characteristics of the coupling between the lower-level loops is taken into account. This leads to a design method emphasizing the trade-off between the individual loop performances and the so called interaction indices. The controller is easily implemented, due to its simple configuration based on standard components. The method is applied to a couple of examples.

  • 126675.
    Åström, Katja
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Utveckling av en induktionsladdare för bärbara datorer2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report was written in conjunction with a bachelor’s work within Engineering Design, during spring 2014, at the Royal Institute of Technology in Stockholm. The aim was to develop a product focusing on both technical and design aspects while at the same time deepening previously acquired knowledge in product development, mechanical engineering, electrical engineering and mathematics.The product that was developed was an inductive charger for laptops, which has not existed on the market before. The aim was to develop a wireless charger as a complement to existing chargers, for times when it is impractical to look for charging jacks and fiddle about with wires. The focus was on applying available technology within a new area rather than developing the technology itself.The result was a portable inductive charger that charges the computer when plugged-in and placed on a table with a built-in charging station. The inductive effect is enhanced by a magnetic ferrite core. Besides, the product is compatible with different types of computers thanks to its adjustable voltage level and universal socket.The groundwork began with an extensive information search about induction and different usage areas. The inductive charging method varies depending on the usage area and by mapping these areas, methods applicable to the project were found. This was followed by a market research and costumer research, followed by a concept development process where pros and cons of different concepts were weighed against each other. During the development of the product, economic, social, environmental and operational aspects were considered. At the end of the report an analysis of the project is presented.

  • 126676.
    Åström, Kjell
    KTH, Superseded Departments.
    Beräkning av my-mesonernas energispektrum vid jordytan i zenitriktningen1981Report (Other academic)
  • 126677. Åström, Mats E.
    et al.
    Nystrand, Miriam
    Gustafsson, Jon Petter
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Österholm, Peter
    Nordmyr, Linda
    Reynolds, Jason K.
    Peltola, Pasi
    Lanthanoid behaviour in an acidic landscape2010In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 74, no 3, p. 829-845Article in journal (Refereed)
    Abstract [en]

    Lanthanoids were studied in a boreal landscape where an abundance of acid sulfate soils and Histosols provide a unique opportunity to increase the understanding of flow these metals behave in acidic soils and waters and interact with soil and aqueous organic matter. In the acid sulfate soils lanthanoids are mobile as reflected in high to very high concentrations in soil water and runoff (typically a few mg 1(-1) but Lip to 12 mg 1(-1)) and abundant release by several relatively weak extractants (ammonium acetate EDTA, sodium pyrophosphate, hydroxylamine hydrochloride) applied on bulk soil. Normalisation with the lanthanoid pool in the underlying parent materials (sulphide-bearing sediments deposited in brackish-water) and soil water showed that the extensive release/retention in the acidic soil was accompanied by large, and variable, fractionation trends across the lanthanoid series. In low-order streams draining these soils, the lanthanoid concentrations were high and, as indicated by frontal ultrafiltration and geochemical modelling, largely dissolved (<1 kDa) in the form of the species LnSO(4)(+) and Ln(3+). In other moderately acidic stream waters (pH 4.3-4.6), organic complexation was predicted to be important in the <1 kDa fraction (especially for the heavy lanthanoids) and strongly dominating in the colloidal phase (1 kDa-0.45 mu m). Along the main stem of a stream in focus (catchment area of 223 km(2)), lanthanoid concentrations increased downstream, in particular during high flows, caused by a downstream increase in the proportion of acid sulfate soils which are extensively flushed during wet periods. The geochemical models applied to the colloidal Ln-organic phase were not successful in predicting the measured fractionation patterns.

  • 126678. Åström, Mats E.
    et al.
    Österholm, Peter
    Gustafsson, Jon Petter
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Nystrand, Miriam
    Peltola, Pasi
    Nordmyr, Linda
    Boman, Anton
    Attenuation of rare earth elements in a boreal estuary2012In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 96, p. 105-119Article in journal (Refereed)
    Abstract [en]

    This study focuses on attenuation of rare earth elements (REE) when a boreal creek, acidified and loaded with REE and other metals as a result of wetland drainage, empties into a brackish-water estuary (salinity < 6 parts per thousand). Surface water was collected in a transect from the creek mouth to the outer estuary, and settling (particulate) material in sediment traps moored at selected locations in the estuary. Ultrafiltration, high-resolution ICP-MS and modeling were applied on the waters, and a variety of chemical reagents were used to extract metals from the settling material. Aluminium, Fe and REE transported by the acidic creek were extensively removed in the inner/central estuary where the acidic water was neutralised, whereas Mn was relatively persistent in solution and thus redistributed to particles and deposited further down the estuary. The REE removal was caused by several contemporary mechanisms: co-precipitation with oxyhydroxides (mainly Al but also Fe), complexation with flocculating humic substances and sorption to suspended particles. Down estuary the dissolved REE pool, remaining after removal, was fractionated: the < 1 kDa pool became depleted in the middle REE and the colloidal (0.45 mu m-1 kDa) pool depleted in the middle and heavy REE. This fractionation was controlled by the removal process, such that those REE with highest affinity for the settling particles became most depleted in the remaining dissolved pool. Modeling, based on Visual MINTEQ version 3.0 and the Stockholm Humic Model after revision and updating, predicted that the dissolved (< 0.45 mu m) REE pool in the estuary is bound almost entirely to humic substances. Acid sulphate soils, the source of the REE and other metals in the creek water, are widespread on coastal plains worldwide and therefore the REE attenuation patterns and mechanisms identified in the studied estuary are relevant for recognition of similar geochemical processes and conditions in a variety of coastal locations.

  • 126679.
    Åström, Oskar
    KTH, School of Architecture and the Built Environment (ABE), Architecture.
    House of Darkness2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    To go straight to the point the theme of this thesis is about darkness and shadows. To be more precise the study aims to explore how they can be created and manipulated, and find ways to work with them in a building. For the purpose of applying these findings I have designed what I call a “House of Darkness”; a building that gives the visitor an architectural experience of the dark. The thesis question that follows is: How can geometry and light sources be utilised in the creation of a murky interior world of shadows that makes use of the rich associative character of darkness? 

    The project works with two modes of darkness; abstract interiors that deal more physically with light and shadow and those which play with the associative qualities of that. This division is visible in the two series of study models, and the two types of interiors of the building. In summary the aim of this thesis project has not only been to create the physical effect of darkness and shadows, but to make use of some of their associative richness to create suggestive interiors.

  • 126680.
    Åström, Oskar
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Architecture.
    Fröderberg, Max
    KTH, School of Architecture and the Built Environment (ABE), Architecture.
    Kv. Draken: En studie i kostnadseffektivt byggande2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The housing policy conducted over the past two decades has resulted in an increasingly segregated city center in Stockholm. The abolishment of housing subsidies in the 90s led to a historic low rate of construction and an urban development unilaterally directed towards the wealthy.

    Parallel to this, much of the housing stock has been converted to condominiums which caused many relatively cheap rental apartments in older buildings to disappear from the stock. These are difficult to replace with new housing, as they are more expensive.

    The core issue is of course that it is expensive to build houses and assuming that the current housing policy will last, ​​it is highly relevant to develop cost-effective construction methods in order to make possible apartments with affordable rents that can help to combat segregation over time.

    Our proposal consists of a residential building in Stadshagen. The property is divided into two buildings that are linked together by a system of access balconies connected to a stairwell. The houses are constructed with volume elements stacked on a concrete base. The design of the elements is based on shipping containers which provides a rational construction process and a high degree of prefabrication. The base contains an underground entrance, a business premise and common areas for the residents. The apartments are available in three sizes whereof the larger apartments have two floors.

  • 126681.
    Åström Paulsson, Sofia
    et al.
    Uppsala Universitet.
    Schmidt, Lisa
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Eriksson, Tomas
    Uppsala Universitet.
    Nyman, Teresia
    Uppsala Universitet.
    Parmsund, Marianne
    Torgén, Margareta
    Svartengren, Magnus
    Uppsala Universitet.
    Procurement and implementation processes for Occupational Health Services in SwedenIn: International Archives of Occupational and Environmental Health, E-ISSN 1432-1246Article in journal (Refereed)
    Abstract [en]

    Purpose: This study investigates how contracts with OHS-providers in Sweden are established and implemented  to explore i) the procurement process ii) contractual terms and conditions and iii) processes for implementing and evaluating the services provided.

    Methods: Review and analysis of 17 OHS contracts using both quantitative and qualitative approaches. Follow-up interviews were conducted with Human Resource managers, management, health and safety representatives and OHS professionals.

    Results: Contracts with OHS providers were mainly drawn up by HR departments. First-line managers or health and safety representatives were not involved. The contracts were not integrated with the companies’ occupational health and safety management. The organisations lacked knowledge on when or why to use services from their OHS provider, which promoted reactive rather than preventive interventions. Terms and conditions of contracts were found to be quite irrelevant to what services that were actually utilised.

    Conclusions: Important factors in creating conditions for a more preventive and group-oriented use of OHS expertise could be 1) the inclusion of first-line managers and health and safety representatives in needs analysis and implementation processes, 2) the definition of relevant, achievable and measurable goals regarding the collaboration and 3) the arrangement of regularly meetings with the OHS-provider.

  • 126682.
    Åström, Per
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Industrial Management.
    Hespe, Tobias
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Industrial Management.
    The Effects of an Increased Traceability on Lead Times: A case study on a material replenishment system at a Swedish industrial tools manufacturer2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study investigates the relationship between an increased traceability and shortened lead times in the internal material replenishment system at a large Swedish industrial tools manufacturer. Traceability and its effects on uncertainty in the supply chain has been widely researched in academia, but there is a gap regarding how traceability affects lead times.

    The research investigates which factors drive the lead times in the material replenishment to lean assembly lines and determines how these factors relate to traceability. A case study was conducted in one of the case company’s factories. The study consists of both quantitative and qualitative data. The quantitative data was derived from the case company’s ERP-system while the qualitative data consists of interviews and empirically collected data.

    The results of the study show that waiting time is the primary driver of lead times in the current state of the factory. No indication that internal material replenishment lead times decrease as a result of an increased traceability was found. However, there are aspects with an increased traceability that indirectly facilitates reduction of lead times by making it easier to make well-informed decisions due to the increased availability of real-time data.

    Traceability is found to not contribute any value to the end customer on its own. However, it can play an important role in a company’s supply chain. Further, potential advantages with a high traceability were observed when implementing advanced protocols such as JIT and other lean principles. The study should be seen as a starting point to further studies into the relationship between increasing traceability and reduced internal lead times.

    For managers and companies, the study identifies a potential procedure to use for deter- mining which factors drive replenishment lead times to lean assembly lines. Furthermore, the study shows that companies can have great use for traceability when trying to remove waste from its processes.

  • 126683.
    Åström, Teodor
    KTH, School of Architecture and the Built Environment (ABE), Architecture.
    Conic Intersections: Art Centre in Solna2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The cone in architecture has often been used to shape and generate space with a cellular structural logic. This project reconsiders the use of the cone for organizing space, in this case applied on an Art Centre in Solna, going beyond the mere repetitive logic of conic modules, to allow for a variety of scales and directions, ranging from large span horizontal conic spaces to more intimate smaller scaled vertical conic rooms.

    The spaces are created through an additive process of intersecting cones with planar elements added into the operation, thus allowing the coexistence of two spatial logics, leading towards a manifold and allowing architecture that can handle the requirements of the program and that reinforces the perception of the shape.

    The project also explores the possibilities of the cone as a single curved unfoldable surface and it’s implications on digital model making, drawing and physical construction.

  • 126684. Åström, Tomas
    et al.
    Brown, Neil
    Wain, Martin
    Nielsen, Kalle
    Potau, Xavier
    Arnold, Erik
    Philosophy and History, KTH, School of Architecture and the Built Environment (ABE), Philosophy and History of Technology, History of Science, Technology and Environment.
    How can the EU Framework Programme for Research and Innovation increase the economic and societal impact of RDI funding in Finland?2018Report (Other academic)
  • 126685.
    Åsén, Per-Olov
    KTH, Superseded Departments, Numerical Analysis and Computer Science, NADA.
    A parallel code for direct numerical simulations of pipe Poiseuille flowManuscript (Other academic)
  • 126686.
    Åsén, Per-Olov
    KTH, Superseded Departments, Numerical Analysis and Computer Science, NADA.
    A proof of a resolvent estimate for plane flow by new analytical and numerical techniques2004Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    This thesis concerns stability of plane Couette flow in three space dimensions for the incompressible Navier-Stokes equations. We present new results for the resolvent corresponding to this flow. Previously, analytical bounds of the resolvent have been derived in parts of the unstable half-plane. In the remaining part, only bounds based on numerical computations in an infinite parameter domain are available. Due to the need for truncation of this infinite parameter domain, these results are mathematically insufficient.

    We obtain a new analytical bound of the resolvent at s = 0 in all but a compact subset of the parameter domain. This is done by deriving approximate solutions of the Orr-Sommerfeldt equation and bounding the errors made by the approximations. In the remaining compact set, we use standard numerical techniques to obtain a bound. Hence, this part of the proof is not rigorous in the mathematical sense.

    In the thesis, we present a way of making also the numerical part of the proof rigorous. By using analytical techniques, we reduce the remaining compact subset of the parameter domain to a finite set of parameter values. In this set, we need to compute bounds of the solution of a boundary value problem. By using a validated numerical method, such bounds can be obtained. In the last part of the thesis, we investigate a validated numerical method for enclosing the solutions of boundary value problems.

  • 126687.
    Åsén, Per-Olov
    KTH, School of Computer Science and Communication (CSC), Numerical Analysis and Computer Science, NADA.
    Stability of plane Couette flow and pipe Poiseuille flow2007Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    This thesis concerns the stability of plane Couette flow and pipe Poiseuille flow in three space dimensions. The mathematical model for both flows is the incompressible Navier--Stokes equations. Both analytical and numerical techniques are used.

    We present new results for the resolvent corresponding to both flows. For plane Couette flow, analytical bounds on the resolvent have previously been derived in parts of the unstable half-plane. In the remaining part, only bounds based on numerical computations in an infinite parameter domain are available. Due to the need for truncation of this infinite parameter domain, these results are mathematically insufficient.

    We obtain a new analytical bound on the resolvent at s=0 in all but a compact subset of the parameter domain. This is done by deriving approximate solutions of the Orr--Sommerfeld equation and bounding the errors made by the approximations. In the remaining compact set, we use standard numerical techniques to obtain a bound. Hence, this part of the proof is not rigorous in the mathematical sense.

    In the thesis, we present a way of making also the numerical part of the proof rigorous. By using analytical techniques, we reduce the remaining compact subset of the parameter domain to a finite set of parameter values. In this set, we need to compute bounds on the solution of a boundary value problem. By using a validated numerical method, such bounds can be obtained. In the thesis, we investigate a validated numerical method for enclosing the solutions of boundary value problems.

    For pipe Poiseuille flow, only numerical bounds on the resolvent have previously been derived. We present analytical bounds in parts of the unstable half-plane. Also, we derive a bound on the resolvent for certain perturbations. Especially, the bound is valid for the perturbation which numerical computations indicate to be the perturbation which exhibits largest transient growth. The bound is valid in the entire unstable half-plane.

    We also investigate the stability of pipe Poiseuille flow by direct numerical simulations. Especially, we consider a disturbance which experiments have shown is efficient in triggering turbulence. The disturbance is in the form of blowing and suction in two small holes. Our results show the formation of hairpin vortices shortly after the disturbance. Initially, the hairpins form a localized packet of hairpins as they are advected downstream. After approximately $10$ pipe diameters from the disturbance origin, the flow becomes severely disordered. Our results show good agreement with the experimental results.

    In order to perform direct numerical simulations of disturbances which are highly localized in space, parallel computers must be used. Also, direct numerical simulations require the use of numerical methods of high order of accuracy. Many such methods have a global data dependency, making parallelization difficult. In this thesis, we also present the process of parallelizing a code for direct numerical simulations of pipe Poiseuille flow for a distributed memory computer.

  • 126688.
    Åsén, Per-Olov
    et al.
    KTH, School of Computer Science and Communication (CSC), Numerical Analysis and Computer Science, NADA.
    Kreiss, Gunilla
    KTH, School of Computer Science and Communication (CSC), Numerical Analysis and Computer Science, NADA.
    On a Rigorous Resolvent Estimate for Plane Couette Flow2007In: Journal of Mathematical Fluid Mechanics, ISSN 1422-6928, E-ISSN 1422-6952, Vol. 9, no 2, p. 153-180Article in journal (Refereed)
    Abstract [en]

    We derive a rigorous bound of the solution of the resolvent equation for plane Couette flow in three space dimensions. We combine analytical techniques with numerical computations. Compared to earlier results, our analytical techniques cover a larger part of the parameter domain consisting of wave numbers in two space directions and the Reynolds number. Numerical computations are needed only in a compact subset of the parameter domain.

  • 126689.
    Åsén, Per-Olov
    et al.
    KTH, School of Computer Science and Communication (CSC), Numerical Analysis and Computer Science, NADA.
    Kreiss, Gunilla
    KTH, School of Computer Science and Communication (CSC), Numerical Analysis and Computer Science, NADA.
    Resolvent bounds for pipe Poiseuille flow2006In: Journal of Fluid Mechanics, ISSN 0022-1120, E-ISSN 1469-7645, Vol. 568, p. 451-471Article in journal (Refereed)
    Abstract [en]

    We derive an analytical bound on the resolvent of pipe Poiseuille flow in large parts of the unstable half-plane. We also consider the linearized equations, Fourier transformed in axial and azimuthal directions. For certain combinations of the wavenumbers and the Reynolds number, we derive an analytical bound on the resolvent of the Fourier transformed problem. In particular, this bound is valid for the perturbation which numerical computations indicate to be the perturbation that gives the largest transient growth. Our bound has the same dependence on the Reynolds number as given by the computations.

  • 126690.
    Åsén, Per-Olov
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    Kreiss, Gunilla
    Uppsala Univ, Dept Informat Technol..
    Rempfer, Dietmar
    IIT, Chicago.
    Direct numerical simulations of localized disturbances in pipe Poiseuille flow2010In: Computers & Fluids, ISSN 0045-7930, E-ISSN 1879-0747, Vol. 39, no 6, p. 926-935Article in journal (Refereed)
    Abstract [en]

    We consider pipe Poiseuille flow subjected to a disturbance which is highly localized in space. Experiments by Peixinho and Mullin have shown this disturbance to be efficient in triggering turbulence, yielding a threshold dependence on the required amplitude as R-1.5 on the Reynolds number, R. The experiments also indicate an initial formation of hairpin vortices, with each hairpin having a length of approximately one pipe radius, independent of the Reynolds number in the range of R = 2000-3000. We perform direct numerical simulations for R = 5000. The results show a packet of hairpin vortices traveling downstream, each having a length of approximately one pipe radius. The perturbation remains highly localized in space while being advected downstream for approximately 10 pipe diameters. Beyond that distance from the disturbance origin, the flow becomes severely disordered.

  • 126691.
    Åteg, Mattias
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    Aktiviteter och lärande för attraktivt arbete.: Utvecklingsprocesser inom verkstadsindustrin2006Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [sv]

    Avhandlingsarbetet utgår från ett nätverk av mindre verkstadsföretag som under mer än fem års tid varit engagerade i utvecklingsprocesser för att skapa mer attraktiva arbeten. Arbetet har genomförts inom ramen för att…-projektet i samverkan mellan Högskolan Dalarna och Arbetslivsinstitutet. Det övergripande syftet är att utveckla kunskap om och förståelse för utvecklingsprocesser med utgångspunkt i att skapa mer attraktivt arbete. Särskilt intresse ägnas åt hur dynamiken i utvecklingsprocesserna kan analyseras utifrån ett lärandeperspektiv. Ett resonemang förs om utvecklingsprocessernas karaktär och om egenskaper i arbetets attraktivitet. Ansatsen kan beskrivas som interaktiv forskning med tät interaktion med praktiker i verkstadsföretag och i lokalt utvecklingsarbete. Metodansatsen är aktions-, och processorienterad. Attraktivt arbete ses som ett processuellt begrepp, dvs ett strävansmål utifrån individers upplevelser, vilka är stadda under förändring. En distinktion görs mellan en skalbetonad (tilldragande) och en innehållsbetonad (behållande) egenskap. Avhandlingen baseras på fyra delstudier.

    Utifrån tidigare forskning och eget material skapas en analysram över utvecklingsprocessers dynamik avseende aktivitetsnivåer och lärdimensioner. Processer kan ut¬ifrån ramen karaktäriseras som ställföreträdande förändring, skalförändrande utveckling, temporärt förändrande utveckling eller reflektiv utveckling. Faktaunderlag och diskussioner har i en spegelmetod utgjort grund för företagens reflektion om interna och externa förhållanden. Aktiviteter för att skapa attraktiva arbeten har skett på diagnos-, intentions-, och handlingsnivå. Analysramen tillämpas på dels utvecklingsprocesser inom fem verkstadsföretag, dels lokalt utvecklingsarbetet för mer attraktiv industriutbildning.

  • 126692.
    Åteg, Mattias
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    Attraktiv industriutbildning på gymnasiet: Ett deltagandeperspektiv på lokalt utvecklingsarbete2005In: Arbetsliv i omvandling, ISSN 1404-8426, Vol. 2, p. 1-110Article in journal (Refereed)
    Abstract [sv]

    Studiens syfte var att skapa förståelse för hur lokalt utvecklingsarbete kan öka industriprogrammetsattraktivitet för ungdomar i valet av gymnasieutbildning, och för att programmet ska vara attraktivt förelever som studerar på programmet.Ett särskilt intresse ägnas åt samverkan mellan gymnasieskola och lokala verkstadsföretag, samt åtinsatser med betoning på utveckling av den arbetsplatsförlagda utbildningen – APU.Under ett flertal år har antalet elever på industriprogrammet i Sverige minskat kraftigt. Samtidigt sermånga industriföretag en brist på utbildad arbetskraft som ett stort hinder för framtiden.Sökandetrycket, mätt i antalet förstahandssökande, har minskat med mer än tre fjärdedelar sedan slutetav 1980-talet.År 2001 sökte två elever till industriprogrammet i Avesta. Insatser för att öka industriprogrammetsattraktivitet fick ett överväldigande resultat – totalt 63 elever sökte till industriprogrammet 2002.Tjugonio elever sökte programmet i första hand.Undersökningar har gjorts av hur ungdomar som sökt och studerar på industriprogrammet sett på sittgymnasieval, på utbildningen, på APU samt på ett framtida industriarbete. Ett särskilt fokus har varit omeleverna gett uttryck av att vara vilseledda och inlurade på utbildningen genom insatser för ett merattraktivt industriprogram.Information om industriprogrammet, om branschen och om industriarbete har visat sig vara av stortvärde för att öka utbildningens attraktivitet. Vikten av en ärlig bild poängteras: det är bättre att visa upprealistiska arbetsmiljöer och arbetsinnehåll, än att peka på en alltför ”modern” bild som branschen intekan leva upp till.Tidigare litteratur har visat att elever har känt sig utnyttjade då de ingått i den ordinarie produktionen påAPU. I denna studie har eleverna istället ansett detta vara något positivt. Det har gett en känsla av att fåarbeta ”på riktigt”, samtidigt som det gett större acceptans för det som varit tråkigare eller mindreintressant. Eleverna som fått arbeta i produktionen har förmedlat en känsla av att ha blivit behandladesom de anställdas jämlikar.

  • 126693.
    Åteg, Mattias
    et al.
    Högskolan i Dalarna.
    Andersson, Ing-Marie
    Högskolan i Dalarna.
    Rosén, Gunnar
    Högskolan i Dalarna.
    Change Processes for Attractive Work in Small Manufacturing Companies2009In: Human Factors and Ergonomics in Manufacturing, ISSN 1090-8471, E-ISSN 1520-6564, Vol. 19, no 1, p. 35-63Article in journal (Refereed)
    Abstract [en]

    The article originates from research in interaction between researchers and companies in a network,which has led to an increasing awareness among managers on issues such as reasons behind difficultiesin attracting competent labor. Particularly, attention has been directed toward the importance ofwork environment improvements that increase the attractivity of industrial work. To deal with suchchallenges, for more than 5 years a number of small engineering companies, with research support,have been engaged in change processes based on the concept of attractive work. The purpose of thearticle is to develop knowledge and understanding for how small engineering companies can createmore attractive work. One goal is to make it possible to draw conclusions about the employees’ experiencesof changes in the attractivity of industrial work. Efforts in this direction have been conductedthrough work environment assessments (before and after the changes) and through administration ofa questionnaire. The results show that it is possible to analyze how employees experience changes inthe attractivity of work. This is most interesting from the perspective that the results can be used forassisting further improvements.

  • 126694.
    Åteg, Mattias
    et al.
    KTH, Superseded Departments, Industrial Economics and Management.
    Hedlund, Ann
    KTH, Superseded Departments, Industrial Economics and Management.
    Pontén, Bengt
    Attraktiv arbete: från anställdas uttalanden till skapandet av en modell2004In: Arbetsliv i omvandling, ISSN 1404-8426, Vol. 1, p. 63-Article in journal (Refereed)
    Abstract [en]

    The purpose of the study was to create a deeper knowledge and understanding ofwhat makes work attractive, and to create a model and to test the possibility togeneralize the model. The study had a qualitative approach, with a starting pointin a mapping method.The results of the study are put in relation to prior research, constituted bytheories on organization and motivation, and in relation to literature on attractivework and adjacent concepts. An establishment was that the prior literature onattractive work is not adequate to give an understanding for what makes workattractive, due to unsuitable starting points.Three different categories have been identified in the analyses of the empiricalmaterial. Attractive work contents include dimensions that deal with what andhow the employee is doing during the performance of the job. Examples areworking speed, freedom of action and variation. Work satisfaction includesdimensions that deal with what the employee think he or she gets out of doing thejob. Examples are acknowledgement, status and stimulation. Attractive workingconditions deal with dimensions that are common for every employee within acompany or organization. These dimensions are not dependent on the specificwork tasks of how the employee thinks about what he or she gets out of doing thejob. Examples are working hours, physical work environment and leadership.The model of attractive work represents an overall picture about what makeswork attractive and it can form a base for continued research or developmentwork. The contents of the model corresponds to what prior research has shown isimportant. But at the same time there is a need to de-learn some of the old structuresof thought, since they include features that in some cases constitutes theopposite to an attractive work.

  • 126695. Åvitsland, G.A.
    et al.
    Sterner, M.
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Ödberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    AKD sizing of TCP and ECF bleached birch pulp characterized by peroxide edge wicking index2006In: Nordic Pulp and Paper Research Journal, ISSN 0283-2631, Vol. 21, no 2, p. 237-244Article in journal (Refereed)
    Abstract [en]

    To study the impact of extractable materials and xylan on the sizing efficiency of totally chlorine-free (TCF) bleached birch pulp and elemental-chlorine-free (ECF) bleached birch pulp, several pulps with different amounts of extractable material were studied. The content of extractable material in the pulp was shown to be detrimental for sizing efficiency, measured both as Cobb60 values and edge penetration in a model liquid packaging board, and a higher content of extractable material causes a reduced sizing efficiency for a given pulp. No significant difference was observed between extracted TCF and ECF bleached birch pulps, while unextracted pulps containing the same amount of extractable material yielded different sizing efficiencies. The TCF bleached birch pulp had a lower sizing efficiency than did the ECF bleached birch, probably because of differences in the fatty acid composition. A greater amount of extractable material also resulted in a smaller fraction of non-extractable alkyl ketene dimers (AKD) relative to the total amount of AKD in the sheet. Enzymatic removal of xylan and thus the reduction of the surface charge had no measurable effect on sizing efficiency. Extracted TCF and ECF bleached pulps only need a content of 0.05 kg/ton non-extractable AKD or 0.08 kg/ton total AKD in the sheets produced to achieve a good sizing effect.

  • 126696.
    Åvitsland, Grete
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Impact of heat treatment on hygroexpansion, absorption and pore structrure of paper and boardManuscript (Other academic)
  • 126697.
    Åvitsland, Grete A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Edgewise liquid penetration in paper: influence of surface chemistry and paper structure2005Licentiate thesis, comprehensive summary (Other scientific)
  • 126698. Åvitsland, Grete
    et al.
    Sterner, Mirjam
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Ödberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    AKD sizing of TCF and ECF bleached birch pulp characterized by peroxide edge wicking2006In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 21, no 2, p. 237-241Article in journal (Refereed)
    Abstract [en]

    To study the impact of extractable materials and xylan on the sizing efficiency of totally chlorine-free (TCF) bleached birch pulp and elemental-chlorine-free (ECF) bleached birch pulp, several pulps with different amounts of extractable material were studied. The content of extractable material in the pulp was shown to be detrimental for sizing efficiency, measured both as Cobb. values and edge penetration in a model liquid packaging board, and a higher content of extractable material causes a reduced sizing efficiency for a given pulp. No significant difference was observed between extracted TCF and ECF bleached birch pulps, while unextracted pulps containing the same amount of extractable material yielded different sizing efficiencies. The TCF bleached birch pulp had a lower sizing efficiency than did the ECF bleached birch, probably because of differences in the fatty acid composition. A greater amount of extractable material also resulted in a smaller fraction of non-extractable alkyl ketene dimers (AKD) relative to the total amount of AKD in the sheet. Enzymatic removal of xylan and thus the reduction of the surface charge had no measurable effect on sizing efficiency. Extracted TCF and ECF bleached pulps only need a content of 0.05 kg/ton non-extractable AKD or 0.08 kg/ton total AKD in the sheets produced to achieve a good sizing effect.

  • 126699.
    Åvitsland, Grete
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. Billerud Skärblacka AB, Sweden.
    Wågberg, Lars
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Flow resistance of wet and dry sheets used for preparation of liquid packaging board2005In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 20, no 3, p. 345-353Article in journal (Refereed)
    Abstract [en]

    The present work has shown that an evaluation of the flow resistance of wet and dry sheets can be used to identify how to improve the resistance against edgewise liquid penetration in liquid packaging board. By application of liquid extrusion measurements it was possible to determine the wet and dry structure of liquid packaging board made from CTMP and chemical pulps typically used in the production of packaging board. The expansion of the papers upon wetting induces a large difference between the dry and wet sheet structure, and the wet pore volume is three to four times the dry pore volume. Sheets made from kraft pulps only expand moderately, whereas sheets made from CTMP expand to a higher extent. Both porosities and flow resistances, calculated from pore volumes, display a large impact of both the wet and dry sheet density. From these results it is clear that CTMP sheets resist flow much less than sheets based on kraft pulps, and even considerably reducing the porosity of CTMP sheets only gives a small effect in the magnitude of the flow resistance. Finally at high levels of sizing it will be difficult to compensate changes in sheet structure with an additional size addition in order to prevent liquid penetration.

  • 126700. Çakir, S.
    et al.
    Eriksson, Magnus
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Koning, C. E.
    Multiblock copolymers of polyamide 6 and diepoxy propylene adipate obtained by solid state polymerization2016In: European Polymer Journal, ISSN 0014-3057, E-ISSN 1873-1945, Vol. 79, p. 13-22Article in journal (Refereed)
    Abstract [en]

    Polyesteramide multiblock copolymers based on polyamide 6 and diepoxy propylene adipate blocks were synthesized. For this purpose a carboxyl-terminated polyamide 6 (Mn = 2400 g/mol, Tm = 205.5 °C) and diepoxy propylene adipate (Mn = 450 g/mol) were separately synthesized and characterized. The incorporation of the oligoester into the polyamide 6 backbone was performed by solid state polymerization (SSP) well below the melting temperature of the polyamide (80-140 °C) so that the physical and thermal properties of the original polyamide 6 block were retained. Formation of the multiblock structure was confirmed by following the increase in molecular weight by SEC, reaction of the end groups by 1H NMR and by following the maintained melting temperature after the copolymerization. These segmented copolymers have molecular weights up to 10 kg/mol, thermal stability of 325 °C at 5% weight loss and a melting temperature of 205 °C.

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