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  • 1.
    Abella, Tricia Jennifer
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    The Creative Approach to Vanguard Projects2011Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A vanguard project is the firm’s entrepreneurial vehicle for exploring opportunities, creating new products, services or markets. This type of projects requires flexibility and innovation to thrive. In this regard, a creative approach to project management is proposed for the successful execution of such projects. This creative approach is summarized in a framework that consists of two main components – flexible planning and creative climate.

    The Central Services project, a vanguard in telecommunications, was used to benchmark the creative project management framework to the current project management methodology of the IT department of TIWS. Results show that there is a gap between the framework and the status quo. Moreover, the Central Services project is not efficiently and effectively managed, therefore, resulting to project delays which consequentially lead to negative company revenues. This reality strengthens the proposition that vanguard projects should be managed differently; hence, the birth of creative project management.

  • 2.
    Abraham, Jonatan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Strand, Anna
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Reseavdrag: En analys av ett arbetsmarknadspolitiskt styrmedel ur ett hållbarhetsperspektiv2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The ability to make tax deductions on travel expenses have been present in Sweden since the late 1920s. The main purpose of the state subsidy has been to improve the mobility in the label market. However, in recent years there has been a heated debate as to if the subsidy is truly socio-economically sustainable or not. The favoritism of car users has also made the matter a question of ecological sustainability.

    The aim of this essay is to analyse and provide general knowledge of the swedish system of deductible travel expenses. The text is divided into four major parts:

    • A litterature review presenting the history of the subsidy, previous research, and the current political debate.
    • A questionnaire survey where the general public’s opinion of tax-deductible travel expenses is examined. 
    • A discussion of possible adjustments of the different parameters of the system, where the most optimal ammendment is chosen
    • An analysis of 3 different scenarios; keeping the current system, using the ammended system obtained in the calibration, and removing the system.

    From the results we could conclude that an ammended system would be noticeably more socio-economically viable and ecologically sustainable, compared with the current system. However, a complete removal of the system would be the most optimal. In addition, the questionnaire surveys results shows that the public is mostly positive to travel deductions. However, it was apparent that the views of many could shift completely, when presenting facts.

  • 3.
    Abrahamsson, Anna-Carin
    KTH, School of Technology and Health (STH).
    Den fysiska arbetsmiljön i förskolan: utveckling, användning och granskning av en riskbedömningsmodell2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The occupational environment in preschool is becoming increasingly important. Occupational injury statistics show an increased incidence of illness among employees in education, health and care. Before action can be taken to improve the working environment, a careful assessment must be made and an action plan created. To include all possible components requires a comprehensive approach. Mapping of the physical work in Hudiksvall Municipality at all preschools provides a means by which to get an overall picture of risk areas within the preschool staff work environment.

    The aim of this work is to describe how the risk assessment model was developed and used with the ambition that it can be used in other municipalities. The model has been tested in Hudiksvall, on two occasions, in 2005 and 2010. The findings from the survey in 2010 are reported here and a comparison with 2005 is made.

    The risk assessment model is based on a survey with open questions for preschool staff combined with observation and assessment of ergonomics and safety engineer of 11 risk areas within the physical environment of the pre-school.

    The results of the survey give a clear picture of current health risks and can be used as a basis for the development of pre-school activities as well as improved maintenance of the municipal buildings. The results have also been communicated to the individual pre-schools to demonstrate their particular areas of risk.

    The combination of survey and professional assessment of several risk areas has been shown to enable a quick identification of possible causes of illness among pre-school staff. To report both positive and negative environmental factors has been an advantage. The clear method of reporting has facilitated decision-making on what if any actions to take. There is a continuing need to develop this and other instruments for the work environment survey of schools, health and social care.

  • 4.
    Abrehdary, Majid
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Sjöberg, Lars E.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Bagherbandi, Mohammad
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Modelling Moho depth in ocean areas based on satellite altimetry using Vening Meinesz–Moritz’ method2016In: Acta Geodaetica et Geophysica Hungarica, ISSN 1217-8977, E-ISSN 1587-1037, Vol. 51, no 2, p. 137-149Article in journal (Refereed)
    Abstract [en]

    An experiment for estimating Moho depth is carried out based on satellite altimetryand topographic information using the Vening Meinesz–Moritz gravimetric isostatichypothesis. In order to investigate the possibility and quality of satellite altimetry in Mohodetermination, the DNSC08GRA global marine gravity field model and the DTM2006 globaltopography model are used to obtain a global Moho depth model over the oceans with aresolution of 1 x 1 degree. The numerical results show that the estimated Bouguer gravity disturbancevaries from 86 to 767 mGal, with a global average of 747 mGal, and the estimatedMoho depth varies from 3 to 39 km with a global average of 19 km. Comparing the Bouguergravity disturbance estimated from satellite altimetry and that derived by the gravimetricsatellite-only model GOGRA04S shows that the two models agree to 13 mGal in root meansquare (RMS). Similarly, the estimated Moho depths from satellite altimetry andGOGRA04S agree to 0.69 km in RMS. It is also concluded that possible mean dynamictopography in the marine gravity model does not significantly affect the Moho determination.

  • 5.
    Acheampong, Josephine
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Entrepreneurship and innovation.
    Green Financing: Financing Circular Economy Companies: Case Studies of Ragn-Sellsföretagen AB and Inrego AB2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The circular economy (CE) has been identified as a catalyst in sustainable development and economic growth that has the potential to move society from the traditional linear model of resource consumption in the form of take-make-waste to an innovative circular model in the form of reduce-reuse-recycle.

    Transitioning from the linear economy to the CE requires changes in four areas: material and product design, business models, global reverse networks and enabling business environments. This study considers the financing needs of CE companies as a result of business model changes.

    Through the case studies of Ragn-Sellsföretagen AB and Inrego AB, analysed with secondary data from ING Bank and primary data collected through semi-structured interviews with the case companies, this research sheds more light on the financing needs of circular economy companies and how they are financed.

    Findings from this research suggest that the financing needs of circular economy companies depend on the value proposition of the company. In accordance with the pecking order of capital structure, all financing needs of the companies studied are financed from internal sources, particularly retained earnings before external debt financing is accessed. Findings indicate the willingness of banks to finance circular economy companies.

    The results of this research suggest that the circular economy companies studied do not need financial support from the government or its agencies to succeed even though favourable laws are welcomed. They report that their long-term success depends on their ability to remain innovative in their business models, aligning with Schumpeter’s creative destruction model.

  • 6.
    AGORAS, DIMITRIS
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Industrial Marketing and Entrepreneurship.
    Building Information Modeling (BIM) Adoption Barriers: An Architectural Perspective2018Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Building Information Modeling (BIM) is the latest development in the Architecture, Engineering and Construction (AEC) Industry. This development can be used for planning, design, construction, operation and maintenance of any facility. The majority of the users of BIM technology are architects. Although its benefits had been highlighted and underlined especially in comparison with older developments such us Computer Aided Design (CAD) tools, its implementation is considered still in an early stage due to low adoption from architects.

    Right now in Sweden and more specifically in the Stockholm area, the construction sector is booming due to the increased demand for housing.  Thus, there is an increased demand for more houses in a shorter time.

    BIM is a technology that can enhance the society in terms of design and construction with regard to the building environment. This can be achieved by avoiding human errors, decreasing project costs, increasing the productivity and quality, and reducing the project delivery time. Moreover, BIM can assist the management team in maintaining and operating different facilities.

    The focus of this research is on the barriers to adopting BIM technology in architectural companies. Furthermore, the attempt will be to investigate the individual, organizational and technical aspects that affect BIM adoption.  This study will implement a qualitative research method by in-depth interviewing four professionals in the area of architectural design.

    This investigation will be driven by the main research question, which is: What are the barriers to adopting Building Information Modeling (BIM) in architectural companies?

  • 7.
    Agrell, Fredrik
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Control of HCCI by aid of Variable Valve Timings with Specialization in Usage of a Non-Linear Quasi-Static Compensation2006Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    This doctoral thesis is about controlling the combustion timing of the combustion concept Homogeneous Charge Compression Ignition, HCCI, by means of variable valve timings.

    The HCCI research usually is regarded to have started in Japan during the later part of the 1970´s. The world of HCCI has since grown and HCCI is of today researched worldwide. Of particular interest from a Swedish point of view is that Lund Institute of Technology has emerged as one of the world leading HCCI laboratories.

    The idea with HCCI is to combine the Otto and Diesel engine. As in an Otto engine the charge is premixed but as in a Diesel engine the operation is unthrottled and the compression heat causes the ignition. The combustion that follows the ignition takes place homogeneously and overall lean. The result is ultra low NOx and particulate emissions combined with high total efficiency. A difficulty with the HCCI-concept is that it only works in a narrow area and that there is no direct way to control the Start Of Combustion, SOC. Out of this follows that timing/phasing of the combustion is one of the main difficulties with HCCI combustion concepts. This is particularly emphasized during transient operation and calls for feedback control of the combustion timing.

    This work investigates one method, the variable valve timing, to achieve feedback control of the combustion phasing. From the work it can be concluded that the variable valve timing can control the combustion phasing during engine transients. In order to improve the performance a non-linear compensation from ignition delay to valve timings has been suggested, incorporated in a control structure and tested in engine test. The engine test has been performed in a single cylinder engine based on a Scania truck engine. The speed range from 500 to 1750 rpm and the load range 1.26 and 10.5 bar of netIMEP has been covered with fair transient performance.

  • 8. Ahlberg, Simon
    et al.
    Hörling, Pontus
    Jöred, Karsten
    Lindström, Björn
    Mårtenson, Christian
    Neider, Göran
    Schubert, Johan
    Sidenbladh, Hedvig
    Svenson, Pontus
    Svensson, Per
    Unden, Katarina
    Walter, Johan
    The IFD03 information fusion demonstrator2004In: Proceedings of the Seventh International Conference on Information Fusion, FUSION 2004, 2004, p. 936-943Conference paper (Refereed)
    Abstract [en]

    The paper discusses a recently developed demonstrator system where new ideas in tactical information fusion may be tested and demonstrated. The main services of the demonstrator are discussed, and essential experience from the use and development of the system is shared.

  • 9.
    Albini, Gabriele Luigi Aldo
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    "An Analysis of the European Telecommunications Strategic Environment: How Can Strategic Actions Be Defined to Adapt to the New Scenario? A Telefónica Case Study"2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This research presents an analysis of the European Telecommunication strategic environment with particular focus on the three macro-changes which have been influencing the recent history of such industry. These are, first of all, the shift from a government-controlled market to a privatized market. Second, the introduction of price limitations - called Eurotariff - which are supposed to regulate the mobile traffic throughout Europe. Finally, the constant growth of data and internet traffic demand, compared to the voice traffic demand, mainly due to the success of OTTs (Over-the-Tops) and the introduction of NGN (Next-Generation Network) applications and software. Such changes have increased the competition in an industry which was organized in monopolies and are forcing the companies to change, following the different customers' needs. Throughout the essay, a case study about Telefónica has been developed: after a presentation of the company and of Telefónica's deregulation process, the consequences of the environment analysis will be defined and, finally, some strategic actions will be proposed in order to adapt to the new strategic environment. The methodology which has been followed consists in a research on the models existing in literature designed to analyze the strategic environment. The best ones have been used and applied to the real case, involving Telefónica: the findings obtained have then been considered the basis to define the strategic actions. The purpose of the paper is twofold: first of all to offer an understanding of the telecommunications business with a particular focus on the Eurotariff, OTTs and NGN phenomena; second to show how a strategic environment can be effectively studied, focusing on the changes that characterize the industry, and how the consequences can be deduced. The information coming from this type of studies is very important for a company to understand what to change in order to adapt to a new context and achieve better performances.

  • 10.
    Albiz, Niccolas
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Sustainability and Industrial Dynamics.
    Sustainability Education at Industrial Engineering Programs in Sweden: A study of the relevant and received sustainability education, and the associated challenges, at 5-year industrial engineering programs2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The public concern for sustainability issues is ever increasing whilst the trust in corporations is decreasing. CEOs now see sustainability concern and compliance as an important component in retaining their competitive advantage and regaining the trust of their surrounding community. For these reasons it is important to find new manners of uniting societal improvement with business, requiring new forms of competencies. This study has investigated what sustainability education is actually central to the industrial engineering profile, as well as what of this is then covered in the programs.

    The study involved two phases. The first involved interviewing experts as to what was central for these engineers to learn, resulting in a content list. The second phase involved mapping the instances of this content in the five largest industrial engineering programs (covering circa 74% of these students) as well as the associated challenges to broaching this content. The first phase was primarily qualitative whilst the second phase was largely quantitative, though each data point consisted of a qualitative interview.

    Five key insights can be drawn from the study regardless of normative stand-point. 1) The sustainability topics that were deemed relevant cover a vast area of disciplines and aspects. 2) There is a skewedness in the content covered, favouring the environmental aspects. 3) There is a lack of integrative instances where the knowledge from different sources and perspectives is synthesized. 4) The key challenges revolve around concept definition and communication. 5) The normativity, interconnectedness and pedagogics contribute with uncertainty and complexity in the assessment of sustainability education.

    The study is finalized with a synthesis of the various insights to arrive at the conclusion that having sustainable business practice as the aim of the programs, establishing common content goals and employing active learning approach would circumvent many of the perceived challenges as well as align the programs with the need of the industry.

    This study contributes with deeper understanding of the sustainability education required and provided to industrial engineering students in Sweden. As such the study has practical applications for the programs studied. The theoretical implications of this study lie in the empirical data achieved regarding the topics of relevance to these engineers, showing high levels of agreement with current literature, as well as the perceived challenges to broaching this content in the current curricula. Furthermore it provides empirical data as to the sustainability education received at different programs.

  • 11.
    Alcaraz Bosca, Neus
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Industrial Economics and Management (Div.).
    Lean project management. Assessment of project risk management processes2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Traditional methods of project management are not appropriate for complex projects anymore. Since projects are becoming increasingly complex and uncertain, interaction between activities and resources is growing in ways not considered by these methods. Nowadays, managers need more agile project management methods that are able to recognize and deal with uncertainty and to produce the expected results. Lean project management, the most recent approach of lean methodology, appears as an alternative approach capable of dealing with complexity and uncertainty. The latest investigations in the field show that traditional methods are still adequate for simple projects, while lean methods are more appropriate for complex projects.

    This thesis aims to investigate the nature of lean project management and to examine project risk management processes so that managers can assess the complexity of projects before their beginning and decide which method to apply in order to manage them. 

  • 12.
    Alvehag, Karin
    et al.
    KTH, School of Electrical Engineering (EES).
    Söder, Lennart
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    A stochastic approach for modeling residential interruption costs2008In: 16th Power Systems Computation Conference, PSCC 2008, Power Systems Computation Conference (PSCC) , 2008Conference paper (Refereed)
    Abstract [en]

    In power system planning and operation, accurate assessment of reliability worth is essential for making informed decisions. The accuracy of the reliability worth estimation is directly affected by the interruption cost model used in the analysis. Residential interruption costs vary with season, day of week and time of day, and can be difficult to handle because of their intangible characteristics. This paper develops a cost model for residential customers that includes the timing of the outage by modeling the underlying factors that give rise to the temporal variations in residential interruption costs. By considering the stochastic nature of the underlying factors, as for example outdoor temperature, the proposed model makes it possible to estimate the costs for an event that is extreme in other senses than having a long duration. Time sequential Monte Carlo simulations were applied to a test system in order to assess reliability worth. The results show that the commonly used customer damage function overestimates the reliability worth. By accounting for the timing of the outages a more realistic estimation of the interruption costs can be obtained.

  • 13.
    Amindezfooli, Soroor
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Analysing the Effect of Angle of Attack on Turbulence Intensity, Wake and Power Production for Hexicon Floating Platform2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    When the wind passes through the wind turbine, it losses a part of its energy and as a result a low momentum region creates behind the wind turbine that refers to the wake.  This effect is more significant in a wind farm, where a group of wind turbines are located close to each other in a specific region. Since the wind speed slows down after passing the first row of the turbine, the other rows at the downstream experience lower wind velocity and consequently they can capture less energy in the wind. Wake effect influences the annual power production of a wind farm, not only because of the reduction in the wind velocity but also because of creating  turbulence in the flow and generating more vibration loads on the rotors which can reduce the lifetime of the turbines and increase fatigue on the blades.  Also when the Angle Of Attack (AOA) changes the shape of the wake varies which influence the annual power production and turbulence intensity of a wind farm. 

    The main purpose of this work is to investigate the effect of changing the AOA on the annual power production and the turbulence intensity of Hexicon platform. For this aim, different AOA between zero and 15 degrees are considered in the simulations.

    ANSYS CFX is applied to model the wind turbine configuration and simulate the fluid flow in different wind direction using unstructured meshing method. In addition wind characteristics profiles such as mean wind velocity, turbulence intensity and length scale at different height are imposed at the inlet of the domain to present the Atmospheric Boundary Layer (ABL). RNG k-ε model is implemented for turbulence modeling. In addition roughness modification is utilized in simulation to get more accurate results in terms of turbulence intensity. 

  • 14.
    Andersson, David
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    From the Electronic Structure of Point Defects to Functional Properties of Metals and Ceramics2007Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Point defects are an inherent part of crystalline materials and they influence important physical and chemical properties, such as diffusion, hardness, catalytic activity and phase stability. Increased understanding of point defects enables us to tailor the defect-related properties to the application at hand. Modeling and simulation have a prominent role in acquiring this knowledge. In this thesis thermodynamic and kinetic properties of point defects in metals and ceramics are studied using first-principles calculations based on density functional theory. Phenomenological models are used to translate the atomic level properties, obtained from the first-principles calculations, into functional materials properties. The next paragraph presents the particular problems under study.

    The formation and migration of vacancies and simple vacancy clusters in copper are investigated by calculating the energies associated with these processes. The structure, stability and electronic properties of the low-oxygen oxides of titanium, TiOx with 1/3 < x < 3/2, are studied and the importance of structural vacancies is demonstrated. We develop an integrated first-principles and Calphad approach to calculate phase diagrams in the titanium-carbon-nitrogen system, with particular focus on vacancy-induced ordering of the substoichiometric

    carbonitride phase, TiCxNy (x+y < 1). The possibility of forming higher oxides of plutonium than plutonium dioxide is explored by calculating the enthalpies for nonstoichiometric defect-containing compounds and the analysis shows that such oxidation is only produced by strong oxidants. For ceria (CeO2) doped with trivalent ions from the lanthanide series we probe the connection between the choice of a dopant and the improvement of ionic conductivity by studying the oxygen-vacancy formation and migration properties. The significance of minimizing the dopant-vacancy interactions is highlighted. We investigate the redox thermodynamics of CeO2-MO2 solid solutions with M being Ti, Zr, Hf, Th, Si, Ge, Sn or Pb and show that reduction is facilitated by small solutes.

    The results in this thesis are relevant for the performance of solid electrolytes, which are an integral part of solid oxide fuel cells, oxygen storage materials in automotive three-way catalysts, nuclear waste materials and cutting tool materials.

  • 15.
    Andersson, David A.
    et al.
    KTH, Superseded Departments, Materials Science and Engineering.
    Simak, S. I.
    Monovacancy and divacancy formation and migration in copper: a first-principles theory2004In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 70, no 11, p. 115108-Article in journal (Refereed)
    Abstract [en]

    The formation and migration of monovacancies and divacancies in copper have been studied from first-principles in order to resolve the discrepancies between previously published experimental and theoretical data. The monovacancy and divacancy formation, migration and binding enthalpies as well as the formation volumes have been calculated in the framework of a plane-wave pseudopotential implementation of the density functional theory, with full structural relaxations included. The monovacancy and divacancy formation entropies have been estimated from experimental data by performing a least-squares analysis. We show that the complete set of first-principles data, taking into account the presence of both vacancies and divacancies as well as the temperature dependence of the formation enthalpies and entropies allow one to reproduce the Arrhenius plot of the total vacancy concentration and the diffusion coefficient, both in good agreement with the most accurate experiments.

  • 16.
    Andersson, David A.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Simak, S. I.
    Skorodumova, N. V.
    Abrikosov, I. A.
    Johansson, Börje
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Modeling of Ce2, Ce2O3 ,and CeO2-x in the LDA+U formalism2007In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 75, no 3, p. 035109-Article in journal (Refereed)
    Abstract [sv]

    The electronic structure and thermodynamic properties of CeO2 and Ce2O3 have been studied from first principles by the all-electron projector-augmented-wave (PAW) method, as implemented in the ab initio total-energy and molecular-dynamics program VASP (Vienna ab initio simulation package). The local density approximation (LDA)+U formalism has been used to account for the strong on-site Coulomb repulsion among the localized Ce 4f electrons. We discuss how the properties of CeO2 and Ce2O3 are affected by the choice of U as well as the choice of exchange-correlation potential, i.e., the local density approximation or the generalized gradient approximation. Further, reduction of CeO2, leading to formation of Ce2O3 and CeO2-x, and its dependence on U and exchange-correlation potential have been studied in detail. Our results show that by choosing an appropriate U it is possible to consistently describe structural, thermodynamic, and electronic properties of CeO2, Ce2O3, and CeO2-x, which enables modeling of redox processes involving ceria-based materials.

  • 17.
    Andersson, David A.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Simak, S. I.
    Skorodumova, N. V.
    Abrikosov, I. A.
    Johansson, Börje
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Redox properties of CeO2-MO2 MO2 (M=Ti, Zr, Hf or Th) solid solutions from first principles calculations2007In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 90, no 3, p. 031909-Article in journal (Refereed)
    Abstract [en]

    The authors have used density functional theory calculations to investigate how the redox thermodynamics and kinetics of CeO2 are influenced by forming solid solutions with TiO2, ZrO2, HfO2, and ThO2. Reduction is facilitated by dissolving TiO2 (largest improvement), HfO2, or ZrO2 (least improvement), while ThO2 makes reduction slightly more difficult. The migration barrier is much lower in the neighborhood of a Ti (largest decrease), Hf, or Zr (least decrease), while the binding energy of solute ions and vacancies increases in the same sequence. They rationalize the properties of ceria solid solutions in terms of defect cluster relaxations.

  • 18.
    Andersson, David A.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Simak, S. I.
    Skorodumova, N. V.
    Abrikosov, I. A.
    Johansson, Börje
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Theoretical study of CeO(2) doped with tetravalent ions2007In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 76, no 7, p. 174119-Article in journal (Refereed)
    Abstract [en]

    We have used density functional theory calculations within the LDA+U formulation to investigate how small amounts of dissolved SiO2, GeO2, SnO2, or PbO2 affect the redox thermodynamics of ceria (CeO2). Compared to pure ceria, reduction is facilitated and the reducibility increases in the sequence of CeO2-SnO2, CeO2-GeO2, and CeO2-SiO2, which correlates with the decrease of the ionic radii of the solutes. For low solute concentrations, there is an inverse relation between high reducibility and the solution energy of tetravalent solutes. CeO2-PbO2 is unique in the sense that the initial reduction occurs by Pb(IV)double right arrow Pb(II) instead of the usual Ce(IV)double right arrow Ce(III) reaction. Among the investigated ceria compounds, CeO2-PbO2 has the lowest reduction energy and rather low solution energy. We have studied how the solution and reduction energies depend on the concentration of Si, Ge, Sn, Pb, Ti, Zr, Hf, and Th solute ions. While the solution energy increases monotonously with concentration, the reduction energy first decreases, as compared to pure ceria (except for Th, which exhibits a small increase), and with further increase of solute concentration, it either remains almost constant (Zr, Hf, and Th) or slightly increases (Ti, Si, Ge, and Sn).

  • 19.
    Andersson, David A.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Simak, Sergei I.
    Skorodumova, Natalia V.
    Abrikosov, Igor A.
    Johansson, Börje
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Optimization of ionic conductivity in doped ceria2006In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 103, no 10, p. 3518-3521Article in journal (Refereed)
    Abstract [en]

    Oxides with the cubic fluorite structure, e.g., ceria (CeO2), are known to be good solid electrolytes when they are doped with cations of lower valence than the host cations. The high ionic conductivity of doped ceria makes it an attractive electrolyte for solid oxide fuel cells, whose prospects as an environmentally friendly power source are very promising. In these electrolytes, the current is carried by oxygen ions that are transported by oxygen vacancies, present to compensate for the lower charge of the dopant cations. Ionic conductivity in ceria is closely related to oxygen-vacancy formation and migration properties. A clear physical picture of the connection between the choice of a dopant and the improvement of ionic conductivity in ceria is still lacking. Here we present a quantum-mechanical first-principles study of the influence of different trivalent impurities on these properties. Our results reveal a remarkable correspondence between vacancy properties at the atomic level and the macroscopic ionic conductivity. The key parameters comprise migration barriers for bulk diffusion and vacancy-dopant interactions, represented by association (binding) energies of vacancy-dopant clusters. The interactions can be divided into repulsive elastic and attractive electronic parts. In the optimal electrolyte, these parts should balance. This finding offers a simple and clear way to narrow the search for superior dopants and combinations of dopants. The ideal dopant should have an effective atomic number between 61 (Pm) and 62 (Sm), and we elaborate that combinations of Nd/Sm and Pr/Gd show enhanced ionic conductivity, as compared with that for each element separately.

  • 20. Andersson, Kurt
    et al.
    Artman, Kristian
    Astell, Magnus
    Axberg, Stefan
    Liwång, Hans
    Lundberg, Anders
    Norsell, Martin
    Tornérhielm, Lars
    Lärobok i Militärteknik, vol. 1: Grunder2007Book (Other academic)
  • 21.
    Andersson, Lars
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Hansson, Mats
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Systematisk kunskapsbrist i skolan?: Arbetsmiljöarbete utan udd2014Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Swedish employers are obliged by law to systematically plan, direct and control activities so that the working environment meets the prescribed requirements. However, evidence indicates that this work is not performed satisfactorily in many schools. This case study aims at mapping out and clarifying how measures towards planning, directing and controlling activities are organized in two public compulsory schools.

     

    The overall purpose of the study is to shed light on elements and conditions that hinder a successful implementation of work environment measures. Our main research questions are: Does the way the municipalities have organized the working environment measures reach the requirements in the law and how controls and follow-ups are performed. Data was collected through the municipalities’ steering documents together with a survey in combination with follow-up interviews with key figures.

     

    Results show that the working environment measures in both schools are organized and performed in similar ways and that the problems reported to a large extent are the same. The unanimous picture shows an organization that is not capable of identifying and handling all important risks. Conclusions from the study indicate that there is a lack of knowledge concerning working environments measures on all levels in the organizations.

  • 22.
    Andersson, Magnus
    KTH, Superseded Departments, Physics.
    Development of a rotation sample holder with high angular resolution1999Report (Other academic)
  • 23.
    Andersson, Magnus
    KTH, Superseded Departments, Physics.
    The Oxford cryostat - a manual1991Report (Other academic)
  • 24.
    Andersson, Magnus
    KTH, Superseded Departments, Physics.
    User manual for the 4He cryostat with an 8 T superconducting coil1998Report (Other academic)
  • 25.
    Andronova, Natalia
    et al.
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Finne, Anna
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Albertsson, Ann-Christine
    KTH, Superseded Departments, Fibre and Polymer Technology.
    Fibrillar structure of resorbable microblock copolymers based on 1,5-dioxepan-2-one and epsilon-caprolactone2003In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 41, no 15, p. 2412-2423Article in journal (Refereed)
    Abstract [en]

    The copolymerization of 1,5-dioxepan-2-one (DXO) and E-caprolactone, initiated by a five-membered cyclic tin alkoxide initiator, was performed in chloroform at 60 degreesC. Copolymers with different molar ratios of DXO (25, 40, and 60%) were synthesized and characterized. C-13 NMR spectroscopy of the carbonyl region revealed the formation of copolymers with a blocklike structure. Differential scanning calorimetry measurements showed that all the copolymers had a single glass transition between -57 and -49 degreesC and a melting temperature in the range of 30.1-47.7 degreesC, both of which were correlated with the amount of DXO. An increase in the amount of DXO led to an increase in the glass-transition temperature and to a decrease in the melting temperature. Dynamic mechanical thermal analysis measurements confirmed the results of the calorimetric analysis, showing a single sharp drop in the storage modulus in the temperature region corresponding to the glass transition. Tensile testing demonstrated good mechanical properties with a tensile strength of 27-39 MPa and an elongation at break of up to 1400%. The morphology of the copolymers was examined with polarized optical microscopy and atomic force microscopy; the films that crystallized from the melt showed a short fibrillar structure (with a length of 0.05-0.4 mum) in contrast to the untreated solution-cast films. (C) 2003 Wiley Periodicals, Inc.

  • 26.
    Angermund, Emma
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    Lindqvist, Emma
    KTH, School of Computer Science and Communication (CSC).
    Working with Time Management in IT Consulting: Developing a Time Management Strategy by Using Performance Management2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Time is in control of our everyday life and work life. Time is a valuable resource of which everyone possesses the same amount. In work life, time is important; it rules the workday and the tasks that are being performed. Time is even more significant within the consultancy industry, where worked time and competence is what is being delivered to the customers. Since time is of great importance for consulting firms, time management systems and time reporting become a crucial part of a consultant’s day. IT consulting firms spend lots of time and money on business systems, despite this the area of how time management and performance management are connected is relatively unexplored.

    This report aims to contribute to an enhanced understanding regarding why consultancy firms work with time management, and how data from time management systems could be used. The study will also investigate how the employees could be motivated to use the time management system in the extent that the managers wish, as well as important requirements on data from the time management system. These questions can together give answer to how time management can be aligned with performance management within an IT consultancy firm.

    The report is based on 14 interviews performed at five different IT consulting firms in the Stockholm area, a participant observation conducted at one of the participating companies, as well as a literature review. The study was performed during the spring of 2013.

    The study found that the main reason for IT consultant firms to report time is to gain decision support for invoices and salary payments. Being able to see overtime and flextime is something that is appreciated by the employees. Other identified areas of usage are forecasts and estimates, evaluations and follow-ups, utilization rate calculations, and employee care. Regular follow-ups, preferable weekly, are necessary for motivating the employees to work with time management. It is also important that the time management system is easy to use in order for it to generate relevant decision support.

    The study shows that to implement a successful time management strategy, the following aspects should be considered: (i) to not measure too much, (ii) to have clear communication and weekly deadlines, (iii) to make it simple, (iv) to create awareness among the employees, and (v) to have a time management system that mutually benefits the managers and the employees.

  • 27.
    ANSELMETTI, Romain
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Entrepreneurship and innovation.
    The Autonomous Vehicle: End of the Road, or the Beginning of A New Era?: Concept and Challenges of a Disruptive Innovation within the Automotive Industry2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The Autonomous Vehicle is about to enter the mass-market. The question is not about when it will happen but in which conditions, under which form or who will be the first car manufacturer to release an efficient and reliable final product.By now, the equation has not been solved, due to the high price of the technologies needed, the lack of solutions to provide a reliable network, and the necessity to change conventions established a long time ago in terms of responsibility of the driver.Depending on who is talking, the Autonomous vehicle is not only an evolution of a previous product, which is able to evaluate and to progressively transform into something different that we could call a self-driven car. This innovation is one step further and is challenging everything that was established until now in terms of objective criteria expected from a car. This is why some are calling this a disruptive innovation, or even a revolution, in the sense that it has the power to totally change the way we are interacting with our everyday transportation system.To enter into the market, this technology, this product, will have to overcome some challenges, on the technological side but also on the psychological side of his future clients.Therefore, this thesis research analyses why this innovation could be the future of the Automotive industry, where it is coming from, what are the challenges it will have to overcome, which will be the impacts, and the different possible scenarios.

  • 28. Antoniou, Constantinos
    et al.
    Koutsopoulos, Haris N.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Traffic and Logistics.
    Ben-Akiva, Moshe
    Chauhan, Akhilendra S.
    Evaluation of diversion strategies using dynamic traffic assignment2011In: Transportation planning and technology (Print), ISSN 0308-1060, E-ISSN 1029-0354, Vol. 34, no 3, p. 199-216Article in journal (Refereed)
    Abstract [en]

    A framework for the evaluation of the effectiveness of traffic diversion strategies for non-recurrent congestion, based on predictive guidance and using dynamic traffic assignment, is presented. Predictive guidance is based on a short-term prediction of traffic conditions, incorporating user reaction to information and guidance. A case study of the Lower Westchester County network in New York State, using DynaMIT-P, is presented to illustrate the application of the framework. DynaMIT-P is capable of evaluating diversion strategies based on predicted conditions, which take into account drivers' response to traffic information. The case study simulates the operations of predictive variable message signs positioned in strategic locations. DynaMIT-P is calibrated for the study network and used to establish base conditions for two incident scenarios in the absence of advanced traveller information systems. The effectiveness of predictive diversion strategies is evaluated (using rigorous statistical tests) by comparing traffic conditions with and without diversion strategies. The empirical findings suggest that incident diversion strategies based on predictive guidance result in travel time savings and increased travel time reliability.

  • 29.
    Aparicio, Francisco
    et al.
    Consejo Superior de Investigaciones Científicas (Spain).
    Holgado, Miguel
    Univ. Politécnica de Madrid.
    Blaszczyk-Lezak, Iwona
    Instituto de Ciencia de Materiales de Sevilla.
    Borras, Ana
    Instituto de Ciencia de Materiales de Sevilla.
    Griol, Amadeu
    Univ. Politécnica de Valencia.
    Barrios, Carlos Angulo
    Univ. Politécnica de Valencia.
    Sohlström, Hans
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Gonzalez-Elipe, Agustí­n R.
    Instituto de Ciencia de Materiales de Sevilla.
    Barranco, Angel
    Incorporation of luminescent nanometric films in photonic crystals and devices for the development of photonic sensors2010Conference paper (Refereed)
    Abstract [en]

    Dye molecules embedded in different matrices in the form of thin films are the basis of specific materials used for laser cavities, optical filters, optical gas sensors, etc. In the present communication we discuss a new methodology based on the remote microwave plasma assisted deposition of dye containing thin films that circumvent the above mentioned problems. It permits a tailored synthesis of optically active nanometric thin films containing dye molecules which are active as fluorescence emitters (i.e., coloured and fluorescent films). The principle of this new procedure is the partial polymerization of dye molecules that are evaporated over a substrate while exposed to a remote microwave Ar plasma. As a result of this process a polymeric thin film is produced in one step where some dye molecules keep intact their optical activity (although eventually, their optical response can be slightly modified by matrix effects). This methodology has been recently used for the deposition of novel plasma nanocomposites containing non-aggregated laser dyes to maximize the fluorescent emission of the materials and for the fabrication of optical NO2 sensing nanocomposites. To illustrate the possibilities of the technique we present here results for different fluorescent dye molecules, as perylene dyes, and several xanthene and oxazine derivative cationic dyes which are typically used as gain media in tuneable laser dyes. The luminescent, optical and sensing properties of these dye containing nanocomposites will be presented. These active optical layers are being developed for the fabrication of photonic sensor devices, optical filters and photonic chips (PHODYE EU Project). This is due to the full compatibility of the synthetic methodology with the present integrated microelectronic and optoelectronic technology. The possibilities for the fabrication of photonic devices integrating these active optical layers will be demonstrated. Especial attention will be paid to recent results about the incorporation of the luminescent films in photonic crystals and about the conformal growth of luminescent planar defects within artificial opals.

  • 30.
    Arone Blanco, Maria
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Effects of herpes simplex virus 1 (HSV-1) infection on nuclear amyloid aggregation2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Huntington’s disease (HD) and Spinocerebellar ataxia (SCA) are incurable neurodegenerative diseases that affect the central nervous system. Amyloids, highly organized protein aggregates, are a hallmark for many neurodegenerative diseases. The presence and accumulation of amyloids are toxic and constitute the major cause of neuron cell death. Both genetic and environmental factors contribute to the onset and progression of these diseases. However, despite intensive research, the underlying cause remains unclear. The role of viral infection as an environmental factor in the context of neurodegenerative diseases has not received much attention. The purpose of this study is to investigate the effects of Herpes Simplex Virus 1 (HSV-1) infection on nuclear amyloid aggregation in model cell lines of HD and SCA. The research process consists mainly of laboratory work which involved the use of several molecular techniques used in the field of biotechnology. The work comprises cultivating cells, infecting cells with HSV-1, Fluorescence microscopy, Western Blot and isolation and detection of amyloids. Western Blot is used for the analysis of specific proteins associated with protein aggregation in HD and SCA. The techniques used for detecting amyloids are Dot Blot and Antibody-staining of amyloids in cells. The results from Western Blot showed that aggregates changed in the presence of the virus. This pattern is observed for both HD and SCA1 cell lines. A big effort is done in this study to optimize Dot Blot as it is method that could be applied in every lab. Normalization of samples proved to be the most challenging part with Dot Blot. No definitive conclusions can be drawn from the Dot Blot results as reproducibility and sensitivity were lacking. This work addresses some of the difficulties encountered when working with detection of amyloids especially Dot Blot. Antibody-staining of amyloids showed that amyloids were formed in the presence of virus in comparison to non-infected. To conclude, aggregates changed, and amyloids were formed in the presence of virus. These results point to the fact that HSV-1 infection could be involved in the process of nuclear amyloid aggregation. The data presented in this thesis will need further investigation and characterization to identify the precise role of viral-induced amyloid formation in HD and SCA patient cells.

  • 31.
    Asplund, Maria
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Hamedi, Mahiar
    Forchheimer, Robert
    Inganäs, Olle
    von Holst, Hans
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Wire electronics and woven logic, as a potential technology for neuroelectronic implantsManuscript (Other (popular science, discussion, etc.))
    Abstract [en]

    New strategies to improve neuron coupling to neuroelectronic implants are needed. In particular, to maintain functional coupling between implant and neurons, foreign body response like encapsulation must me minimized. Apart from modifying materials to mitigate encapsulation it has been shown that with extremely thin structures, encapsulation will be less pronounced. We here utilize wire electrochemical transistors (WECTs) using conducting polymer coated fibers. Monofilaments down to 10 μm can be successfully coated and weaved into complex networks with built in logic functions, so called textile logic. Such systems can control signal patterns at a large number of electrode terminals from a few addressing fibres. Not only is fibre size in the range where less encapsulation is expected but textiles are known to make successful implants because of their soft and flexible mechanical properties. Further, textile fabrication provides versatility and even three dimensional networks are possible. Three possible architectures for neuroelectronic systems are discussed. WECTs are sensitive to dehydration and materials for better durability or improved encapsulation is needed for stable performance in biological environments.

  • 32.
    Asplund, Maria
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Thaning, Elin
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Lundberg, Johan
    Sandberg-Nordqvist, Ann-Christin
    Kostyszyn, Beata
    Inganäs, Olle
    von Holst, Hans
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Biocompatibility of PEDOT/biomolecular composites intended for neural communication electrodesManuscript (Other (popular science, discussion, etc.))
    Abstract [en]

    Electrodes of the conjugated polymer poly(3,4-ethylene dioxythiophene) (PEDOT) have been shown to possess very attractive electrochemical properties for functional electrical stimulation (FES) or recording in the nervous system. Biomolecules already present in nervous tissue, added as counter ions in PEDOT electropolymerisation, could be a route to further improve the biomaterial properties of PEDOT, eliminating the need of surfactant counter ions like docedyl benzene sulphonate (DBS) or polystyrene sulphonate (PSS) in the polymerisation process. Such PEDOT/biomolecular composites using heparin, or hyaluronic acid, have been electrochemically investigated in a previous study and have been shown to retain the attractive electrochemical properties already proven for PEDOT:PSS.

     

    The aim of the present study is to evaluate biocompatibility of these PEDOT/biomolecular composites in vitro and also evaluate PEDOT:heparin biocompatibility in cortical tissue in vivo. Hereby, we also aim to identify a suitable test protocol, that can be used in future evaluations when further material developments are made.

     

    Material toxicity was first tested on cell lines, both through a standardised agarose overlay assay on L929 fibroblasts, and through elution tests on human neuroblastoma SH-SY5Y cells. Subsequently, a biocompatibility in vivo test was performed using PEDOT:heparin coated platinum probes implanted in the cerebral cortex of Sprague-Dawley rats. Tissue was collected at three weeks and six weeks of implantation and evaluated by immunohistochemistry.

     

    No cytotoxic response was seen to any of the PEDOT:biomolecular composites tested here. Furthermore, elution tests were found to be a practical and effective way of screening materials for toxicity and had a clear advantage over the agarose overlay assay, which was difficult to apply on other cell types than fibroblasts. Elution tests would therefore be recommendable as a screening method, at all stages of material development. In the in vivo tests, the stiffness of the platinum substrate was a significant problem, and extensive glial scarring was seen in most cases irrespective of implant material. However, quantification of immunological response through distance measurements from implant site to closest neuron, and counting of macrophage densities in proximity to polymer surface, was comparable to those of platinum controls. These results indicate that PEDOT:heparin surfaces were as compatible with cortical tissue as pure platinum controls.

  • 33.
    Asserstam, Christoffer
    KTH, School of Education and Communication in Engineering Science (ECE).
    Kursutvärdering på Volvo Construction Equipment2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this report an evaluation of current evaluation methods at Volvo CE Service School, which further educates technicians, will be presented. Data from observation and interviews, focusing on constructive alignment and course evaluations is analyzed. It turned out to be inadequate constructive alignment and course evaluations do not provide sufficient information. Through the development of the constructive alignment and by using well-formulated learning outcomes the technicians learning should be enhanced. Also the design of the course evaluation with questions that examines learning factors should contribute to development of the training.

  • 34. Axberg, Stefan
    et al.
    Andersson, Kent
    Bang, Martin
    Bruzelius, Nils
    Bull, Peter
    Eliasson, Per
    Ericson, Marika
    Hagenbo, Mikael
    Hult, Gunnar
    Jensen, Eva
    Liwång, Hans
    Löfgren, Lars
    Norsell, Martin
    Sivertun, Åke
    Svantesson, Carl-Gustaf
    Vretblad, Bengt
    Lärobok i Militärteknik, vol. 9: Teori och metod2013Book (Other academic)
    Abstract [en]

    Ämnet militärteknik utgår från att tekniska system är officerens arbetsredskap och att en förståelse för och kunskap om dessa verktyg är central för att kunna utöva professionen framgångsrikt. Denna nionde volym av Lärobok i Militärteknik, benämnd Teori och Metod, behandlar centrala begrepp, teorier och postulat samt metoder för värdering av teknik och består av ett antal texter författade av 16 forskare och lärare vid den militärtekniska avdelningen. Volymen riktar sig främst till de som inlett sin officersutbildning och utgörs till stora delar av ett kompilat av publicerade och opublicerade militärtekniska texter och kan sägas utgöra militärteknikens ”state of the art”.

  • 35.
    Bagherbandi, Mohammad
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning. University of Gävle, Sweden .
    Sjöberg, Lars E.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Tenzer, Robert
    Abrehdary, Majid
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    A new Fennoscandian crustal thickness model based on CRUST1. 0 and a gravimetric–isostatic approach2015In: Earth-Science Reviews, ISSN 0012-8252, E-ISSN 1872-6828, Vol. 145, p. 132-145Article, review/survey (Refereed)
    Abstract [en]

    In this paper a new gravimetric–isostatic crustal thickness model (VMM14_FEN) is estimated for Fennoscandia. The main motivation is to investigate the relations between geological and geophysical properties, the Moho depth and crust–mantle density contrast at the crust–mantle discontinuity. For this purpose the Bouguer gravity disturbance data is corrected in two main ways namely for the gravitational contributions of mass density variation due to the different layers of the Earth's crust such as ice and sediments, as well as for the gravitational contribution from deeper masses below the crust. This second correction (for non-isostatic effects) is necessary because in general the crust is not in complete isostatic equilibrium and the observed gravity data are not only generated by the topographic/isostatic masses but also from those in the deep Earth interior. The correction for non-isostatic effects is mainly attributed to unmodeled mantle and core boundary density heterogeneities. These corrections are determined using the recent seismic crustal thickness model CRUST1.0. We compare our modeling results with previous studies in the area and test the fitness. The comparison with the external Moho model EuCRUST-07 shows a 3.3 km RMS agreement for the Moho depth in Fennoscandia. We also illustrate how the above corrections improve the Moho depth estimation. Finally, the signatures of geological structures and isostatic equilibrium are studied using VMM14_FEN, showing how main geological unit structures attribute in isostatic balance by affecting the Moho geometry. The main geological features are also discussed in the context of the complete and incomplete isostatic equilibrium.

  • 36.
    Bagheri, Shervin
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    Fransson, Jens H. M.
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    Schlatter, Philipp
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    Research on the interaction between streamwise streaks and Tollmien-Schlichting waves at KTH2007In: ERCOFTAC Bulletin, ISSN 2518-0991, Vol. 74, p. 37-43Article in journal (Refereed)
    Abstract [en]

    This paper summarises the experimental and numericalinvestigations on how two different types of disturbancesmay, in a positive way, interact in a flat plateboundary-layer flow. The project, which mainly hasbeen centered at KTH1, has been performed in collaborationwith colleagues from University of Bologna2and LadHyX CNRS Ecole Polytechnique3, duringthe last years. The main phenomena — the stabilisingeffect of streamwise boundary-layer streakson Tollmien-Schlichting waves (and other exponentialdisturbances) — have been captured both in experiments[1, 2] and with different numerical approachessuch as direct numerical simulations [3], parabolicstability equation calculations [5] and large-eddy simulations[6]. We will here briefly review the methodsand the main results of these studies, and discuss howthey correlate with each other. For related referencesoutside KTH the interested reader is referred to thejournal publications in the reference list.

  • 37.
    Baitar, Rami
    KTH, School of Technology and Health (STH), Medical Engineering, Computer and Electronic Engineering.
    Riskanalys av elsystem med funktions-FMEA2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The risk analysis tool failure mode and effects analysis (FMEA) that analyzes the com-ponents and signals of a electrical system is design dependent and are therefore per-formed late in the development process of electrical systems. This could lead to that some errors are not analyzed in time and may need to be designed away which can lead to increased system complexity as well as longer and more expensive development proc-esses.The objective of this study is that through a literature review identify if there are any methods or approaches that enables Scania to implement a functional hazard analyzes early in the development process of electrical systems and to analyze these.The results of this thesis shows that it is possible to start the FMEA process early in the development process of the electrical system if the engineers have a functional perspec-tive in mind when performing the risk analysis where they list and rank the functions that is provided by the electrical system and their failure modes, failure effects, failure de-tection, severity, probability and occurrence.By using a function based FMEA, the engineer(s) can identify and promptly handle the safety critical functions early in the development process of a electrical system.A existing functionality at Scania has been broken down into functions and a functional hazard analysis has been performed on these as a demonstration of how a function based FMEA can be carried out and look like.

  • 38. Bang, Martin
    et al.
    Liwång, Hans
    Influences on threat assessment in a military context2016In: Defense and Security Analysis, Vol. 32, no 3, p. 264-277Article in journal (Refereed)
    Abstract [en]

    The anchoring effect is a well-studied subject. This article connects the effect with the rules-in-use within a military intelligence institution. Particularly the rules-in-use that dictate that an analyst takes his or hers starting point from recently conducted assessments of the specific area or threat. The threat assessment as well as the written assessment were affected. The results show that officers have an aversion to lower a previous given threat assessment. This gives that to understand risk assessment we not only need to understand the methods used, we also need to understand the institutions in which they are used. This is especially relevant for military intelligence as the assessments are conducted in an environment of high uncertainty.

  • 39.
    Barceló Bartrolí, Laura
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Industrial Marketing and Entrepreneurship.
    The Design Thinking Principles in the Creation Process of User-Centered Value Propositions: An Insight into the Mobile Health Industry2018Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The healthcare and life sciences sectors are currently undergoing a transition towards becoming digitized. Mobile health (mHealth), a subset of digital health, offers many potential benefits to healthcare. Despite that, it has been reported that the majority of mHealth initiatives do not evolve beyond the pilot stage. A core reason seems to be the lack of user-centered value propositions in mHealth projects. Here, we evaluate if the use of the principles of design thinking (DT) can endorse the creation process of user-centered value propositions. For that, several scoping meetings with experts on topics of relevance were carried out, which helped define the scope, the methodology, and formulate the research question in the optimal direction. Interviews with the founders of four startups that operate in the mHealth industry constituted the basis of the findings, with the product or service development process as the central aspect. A framework for DT was employed to analyze the cases, which proposes five themes that should be considered throughout the process: User Focus, Problem Framing, Experimentation, Visualization and Diversity. Our research shows that the use of DT principles can help achieve more valuable outcomes (e.g. more user-centered value propositions), be more efficient and collaborate better. Nevertheless, more knowledge about DT is needed among entrepreneurs, as well as a more uniform consideration of the five themes of DT.

  • 40.
    Basso, Simone
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Power Safety.
    Particulate Debris Spreading and Coolability2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In Nordic design of boiling water reactors, a deep water pool under the reactor vessel is employed for the core melt fragmentation and the long term cooling of decay heated corium debris in case of a severe accident. To assess the effectiveness of such accident management strategy the Risk-Oriented Accident Analysis Methodology has been proposed. The present work contributes to the further development of the methodology and is focused on the issue of ex-vessel debris coolability.

    The height and shape of the porous debris bed are among the most important factors that determine if the debris can be cooled by natural circulation of water. The bed geometry is formed in the process of melt release, fragmentation, sedimentation and packing of the debris in the pool. Bed shape is affected by the coolant flow that induces movement of particles in the pool and after settling on top of the bed. The later one is called debris bed self-leveling phenomenon.

    In this study, the self-leveling was investigated experimentally and analytically. Experiments were carried out in order to collect data necessary for the development of a numerical model with an empirical closure. The self-leveling model was coupled to a model for prediction of the debris bed dryout. Such coupled code allows to calculate the time necessary to have a coolable configuration of the bed. The influence of input parameters was assessed through sensitivity analysis in order to screen out the less influential parameters.

    Results of the risk analysis are reported as complementary cumulative distribution functions of the conditional containment failure probability (CCFP).

    Sensitivity analyses identified: effective particle diameter and debris bed porosity as the parameters that provide the largest contribution to the CCFP uncertainty. It is found that the effect of the initial maximum height of the bed on the CCFP is reduced by the self-leveling.

  • 41. Belson, Brandt A.
    et al.
    Semeraro, Onofrio
    KTH, School of Engineering Sciences (SCI), Mechanics, Stability, Transition and Control.
    Rowley, Clarence W.
    Henningson, Dan Stefan
    KTH, School of Engineering Sciences (SCI), Mechanics, Stability, Transition and Control.
    Feedback control of instabilities in the two-dimensional Blasius boundary layer: The role of sensors and actuators2013In: Physics of fluids, ISSN 1070-6631, E-ISSN 1089-7666, Vol. 25, no 5, p. 054106-1-054106-17Article in journal (Refereed)
    Abstract [en]

    We analyze the effects of different types and positions of actuators and sensors on controllers' performance and robustness in the linearized 2D Blasius boundary layer. The investigation is carried out using direct numerical simulations (DNS). To facilitate controller design, we find reduced-order models from the DNS data using a system identification procedure called the Eigensystem Realization Algorithm. Due to the highly convective nature of the boundary layer and corresponding time delays, the relative position of the actuator and sensor has a strong influence on the closed-loop dynamics. We address this issue by considering two different configurations. When the sensor is upstream of the actuator, corresponding to disturbance-feedforward control, good performance is observed, as in previous work. However, feedforward control can be degraded by additional disturbances or uncertainties in the plant model, and we demonstrate this. We then examine feedback controllers in which the sensor is a short distance downstream of the actuator. Sensors farther downstream of the actuator cause inherent time delays that limit achievable performance. The performance of the resulting feedback controllers depends strongly on the form of actuation introduced, the quantities sensed, and the observability of the structures deformed by the controller's action. These aspects are addressed by varying the spatial distribution of actuator and sensor. We find an actuator-sensor pair that is well-suited for feedback control, and demonstrate that it has good performance and robustness, even in the presence of unmodeled disturbances.

  • 42.
    Bernabini, Alberto
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Entrepreneurship and innovation.
    International Public-Private-Partnerships for startups: an exploratory case study of the diffusion of eco-innovations2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The researcher has investigated what factors influence a startup in an international public-private-partnership (PPP). The researcher has designed an exploratory study with a case study on Greenely, which is a Stockholm-based startup that has developed an application to monitor the household’s electricity consumption. The theoretical framework covers topics such as the diffusion of innovations (in particular eco-innovations in the form of smart meters in Europe), business models, the Business Model Canvas, and public-private-partnerships. The researcher conducted semistructured interviews with employees of the municipality of Cesena, Italy and with employees of Greenely, which is interested in expanding its offerings to Italy via partnerships. This study has shown that the factors that should influence a  tartup in an international PPP are, mainly, five: Funding, Language and cultural identity, Timeline, Common vision and Bureaucracy. The factors “Funding” and “Common vision”, in particular, influence the PPP the most.

  • 43.
    Biltmo, Anders
    KTH, School of Engineering Sciences (SCI), Theoretical Physics.
    Statics, Domain Structure and Dynamics in the Dilute Dipolar Magnet LiHoF42009Doctoral thesis, comprehensive summary (Other academic)
  • 44.
    Biltmo, Anders
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics.
    Henelius, Patrik
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Condensed Matter Theory.
    Glauber Dynamics of Dilute Ising DipolesManuscript (preprint) (Other academic)
  • 45.
    Biltmo, Anders
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics.
    Henelius, Patrik
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Condensed Matter Theory.
    Low-temperature properties of the dilute dipolar magnet LiHoxY1-xF42008In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 78, no 5Article in journal (Refereed)
    Abstract [en]

    We analyze recent experiments on the dilute rare-earth compound LiHoxY1-xF4 in the context of an effective Ising dipolar model. Using a Monte Carlo method we calculate the low-temperature behavior of the specific heat and linear susceptibility and compare our results to measurements. In our model the susceptibility follows a Curie-Weiss law at high temperature, X similar to 1 / (T- T-cw), with a Curie-Weiss temperature that scales with dilution, T-cw similar to x, consistent with early experiments. We also find that the peak in the specific heat scales linearly with dilution, C-max(T)similar to x, in disagreement with recent experiments. This difference could be caused by the hyperfine interaction which is not included in our calculation. Experimental studies do not reach a consensus on the functional form of the susceptibility and specific heat, and in particular, we do not see reported scalings of the form X similar to T-0.75 and X similar to exp(-T/T-0). Furthermore, we calculate the ground-state magnetization as a function of dilution and re-examine the phase diagram around the critical dilution x, = 0.24 +/- 0.03. We find that the spin-glass susceptibility for the Ising model does not diverge below x, while some recent experiments give strong evidence for a stable spin-glass phase in LiHo0.167Y0.833F4.

  • 46.
    Biltmo, Anders
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics.
    Henelius, Patrik
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Condensed Matter Theory.
    Phase diagram of the dilute magnet LiHoxY1-xF42007In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 76, no 5Article in journal (Refereed)
    Abstract [en]

    We study the effective long-range Ising dipole model with a local exchange interaction appropriate for the dilute magnetic compound LiHoxY1-xF4. Our calculations yield a value of 0.12 K for the nearest-neighbor exchange interaction. Using a Monte Carlo method, we calculate the phase boundary T-c(x) between the ferromagnetic and paramagnetic phases. We demonstrate that the experimentally observed linear decrease in T-c with dilution is not the simple mean-field result, but a combination of the effects of fluctuations and the exchange interaction. Furthermore, we find a critical dilution x(c)=0.21(2), below which there is no ordering. In agreement with recent Monte Carlo simulations on a similar model, we find no evidence of the experimentally observed freezing of the glassy state in our calculation. We apply the theory of Stephen and Aharony to LiHoxY1-xF4 and find that the theory does predict a finite-temperature freezing of the spin glass. Reasons for the discrepancies are discussed.

  • 47.
    Biltmo, Anders
    et al.
    KTH, School of Engineering Sciences (SCI), Theoretical Physics.
    Henelius, Patrik
    KTH, School of Engineering Sciences (SCI), Theoretical Physics, Condensed Matter Theory.
    The ferromagnetic transition and domain structure in LiHoF42009In: Europhysics letters, ISSN 0295-5075, E-ISSN 1286-4854, Vol. 87, no 2Article in journal (Refereed)
    Abstract [en]

    Using Monte Carlo simulations we verify that the rare-earth compound LiHoF4 is a very good realization of a dipolar Ising model. With only one free parameter our calculations for the magnetization, specific heat and inverse susceptibility match experimental data at a quantitative level in the 0.5-3 kelvin range, including the ferromagnetic transition at 1.53 K. Using parallel tempering methods and reaching system sizes up to 32000 dipoles with periodic boundary conditions, we are able to give evidence of the logarithmic corrections predicted in renormalization group theory. Due to the long range and angular dependence of the dipolar model, sample shape and domains play a crucial role in the ordered state. We consider surface corrections to Griffiths's theorem, which arise infinite macroscopic samples and lead to a theory of magnetic domains. We find a domain wall energy of 0.059 erg/cm(2) and predict that the ground-state domain structure for cylinders with a demagnetization factor N > 0 consists of thin parallel sheets of opposite magnetization, with a width depending on the demagnetization factor.

  • 48.
    Birgersson, Henrik
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Development of a regeneration procedure for commercial automotive three-wy catalysts2004Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Car exhaust catalysts were introduced in the early 1980’s, to limit the release of pollutants such as hydrocarbons, carbon monoxides and nitrogen oxides. These catalysts contain noble metals such as palladium (Pd), platinum (Pt) and rhodium (Rh) and are able to simultaneously abate all three of the above-mentioned pollutants, hence the name three-way catalyst (TWC). The exposure to high temperatures (800-1000 °C) during operation and the presence of additives in petrol such as lead, calcium, silicon, magnesium, manganese, chromium, sulphur and phosphorus will after a certain time start to lower the overall effectiveness of the catalyst. These effects are either of a mechanical or a chemical nature. High temperatures reduce the active area by causing the noble metals to agglomerate and sinter whereas the additives alter the activity by either fouling the pores of the support material (phosphorus) or by interacting with the metals (sulphur and lead).

    The main objective of this work was to develop a method to redisperse the catalytically active sites, comprising Pd, Pt and Rh on the washcoat surface, in an effort to regain lost catalyst activity. For this purpose, a wide spectrum of different commercial car exhaust catalysts containing varying noble metal loadings, aged under various driving conditions and with mileages ranging from 30 to 100 000 km were evaluated.

    The influence of a thermal treatment in a controlled gas atmosphere, such as oxygen or hydrogen and a redispersing agent, e.g. chlorine, on the activity of TWC was investigated by means of laboratory-scale activity measurements. Several complementary characterisation methods such as SEM/TEM, XRD, BET and TPR were used to verify the effects of the regeneration treatments on the catalyst morphology (Paper I). Partial regeneration of catalyst activity and noble metal dispersion was achieved after thermal treatment in an oxygen-chlorine rich atmosphere at temperatures below 500 °C.

    Finally, an investigation of the effects of an oxy-chlorine thermal treatment for regeneration of a ‘full-scale’ commercial automotive three-way catalyst was performed. Catalyst activity and performance prior to and after the oxy-chlorine thermal treatment was measured on a test vehicle in accordance with the European driving cycle (EC2000). The catalyst surface was further characterised using XRD and EDX (Paper II). Improved catalyst activity for a high mileage catalyst could be observed, with emissions lowered by approximately 30 to 40 vol% over the EC2000 driving cycle

  • 49.
    Birkie, Seyoum Eshetu
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Industrial Management. Politecnico Di Milano.
    Trucco, Paolo
    Politecnico di Milano.
    Kaulio, Matti
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Industrial Management.
    Disentangling core functions of operational resilience: A critical review of extant literature2014In: International Journal of Supply Chain and Operations Resilience, ISSN 2052-8698, Vol. 1, no 1, p. 76-103Article in journal (Refereed)
    Abstract [en]

    This study identifies and systematically reviews the literature on resilience in management research in order to characterise operational resilience. We argue that operational resilience provides an integrative view on different resilience perspectives in business (supply chain, business continuity, infrastructure, organisational, strategic). Using the resource-based view and particularly dynamic capabilities perspective as theoretical lenses, operational resilience is discussed in relation to the core business processes of an enterprise. Five core functions (sense, build, reconfigure, re-enhance, sustain) are identified from literature and discussed taking into account desired and undesired consequences of uncertainties. Moreover, operational resilience is operationalised using routines pertaining to the identified core functions. The proposed operational resilience core functions are further scrutinised using two case examples. Future research is suggested to validate the identified core functions and to use them for empirical analysis, including investigation of relationships with operations management paradigms such as lean thinking.

  • 50.
    Bonde, Magnus
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management, Building and Real Estate Economics.
    Song, Han-Suck
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management, Building and Real Estate Economics.
    The impact of Energy Performance Certificates on Office Rents2013Conference paper (Other academic)
1234567 1 - 50 of 518
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