Digitala Vetenskapliga Arkivet

Endre søk
Begrens søket
567891011 351 - 400 of 18397
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 351.
    Aichmayer, Lukas
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Garrido, Jorge
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Laumert, Björn
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Thermo-mechanical solar receiver design and validation for a micro gas-turbine based solar dish system2020Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 196, artikkel-id 116929Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work presents the comprehensive development of a solar receiver for the integration into a micro gas-turbine solar dish system. Special focus is placed on the thermo-mechanical design to ensure the structural integrity of all receiver components for a wide range of operating conditions. For the development, a 3-dimensional coupled multi-physics model is established and is validated using experimental data. Contrary to previous studies, the temperature of the irradiated front surface of the absorber is included in the comprehensive validation process which results in a high level of confidence in the receiver design.

    Finally, a full-scale solar receiver for the integration into the OMSoP solar dish system is designed and its performance determined for a wide operating range to define its safe operating envelope using the validated model. It is shown that the receiver is capable of operating at 803_C with an efficiency of 82.1% and a pressure drop of 0.3% at the nominal operating point, while at the same time functioning effectively   for a wide range of off-design conditions without compromising its structural integrity. At the nominal operating point, the maximum comparison stress of the porous absorber is 5.6 MPa compared to a permissible limit of 7.4 MPa.

    Fulltekst (pdf)
    fulltext
  • 352.
    Aichmayer, Lukas
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Spelling, James
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Laumert, Björn
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Preliminary design and analysis of a novel solar receiver for a micro gas-turbine based solar dish system2015Inngår i: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 114, nr 4, s. 378-396Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The solar receiver is one of the key components of hybrid solar micro gas-turbine systems, which would seem to present a number of advantages when compared with Stirling engine based systems and photovoltaic panels. In this study a solar receiver meeting the specific requirements for integration into a small-scale (10 kWel) dish-mounted hybrid solar micro gas-turbine system has been designed with a special focus on the trade-offs between efficiency, pressure drop, material utilization and economic design. A situation analysis, performed using a multi-objective optimizer, has shown that a pressurized configuration, where the solar receiver is placed before the turbine, is superior to an atmospheric configuration with the solar receiver placed after the turbine. Based on these initial design results, coupled CFD/FEM simulations have been performed, allowing detailed analysis of the designs under the expected operating conditions. The results show that the use of volumetric solar receivers to provide heat input to micro gas-turbine based solar dish systems appears to be a promising solution; with material temperatures and material stresses well below permissible limits.

  • 353.
    Aichmayer, Lukas
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Spelling, James
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Laumert, Björn
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Small Scale Hybrid Solar Power Plants for Polygeneration in Rural Areas2014Inngår i: Energy Procedia 57, Elsevier, 2014, Vol. 57, s. 1536-1545Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Small scale micro gas-turbine based hybrid solar power plants are a promising technology for supplying multiple energy services in a controllable and sustainable manner using polygeneration technologies. Compared to a conventional diesel generator based system where electricity is used as the main energy carrier, these systems show great potential to reduce costs and carbon dioxide emissions. Depending on the design, carbon dioxide emissions are reduced by around 9% and equivalent annual costs are reduced by 21% - 26%, as compared to a base polygeneration configuration where cooling services are provided centrally by an absorption chiller without integrating a solar micro gas-turbine. Compared to the system where electricity is used as the main energy carrier a reduction of equivalent annual costs of up to 20% and a reduction of carbon dioxide emissions of up to 33.5% was achieved.

    Fulltekst (pdf)
    fulltext
  • 354.
    Aichmayer, Lukas
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Spelling, James
    IMDEA Energy Institute, Spain.
    Laumert, Björn
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Thermoeconomic Analysis of a Solar Dish Micro Gas-Turbine Combined-Cycle Power Plant2015Inngår i: Energy Procedia 69, Elsevier, 2015, Vol. 69, s. 1089-1099Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A novel solar power plant concept is presented, based on the use of a coupled network of hybrid solar-dish micro gas-turbines, driving a centralized heat recovery steam generator and steam-cycle, thereby seeking to combine the high efficiency of the solar dish collector with a combined-cycle power block. A 150 MWe solar power plant was designed based on this concept and compared with both a conventional combined-cycle power plant and a hybrid solar-tower combined-cycle. The solar dish combined-cycle power plant could reach higher levels of solar integration than other concepts but was shown to be more expensive with current technology; solar electricity costs are double those of the hybrid solar-tower combined cycle.

  • 355.
    Aichmayer, Lukas
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Spelling, James
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Laumert, Björn
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Fransson, Torsten
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Micro Gas-Turbine Design for Small-Scale Hybrid Solar Power Plants2013Inngår i: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 135, nr 11, s. 113001-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hybrid solar micro gas-turbines are a promising technology for supplying controllable low-carbon electricity in off-grid regions. A thermoeconomic model of three different hybrid micro gas-turbine power plant layouts has been developed, allowing their environmental and economic performance to be analyzed. In terms of receiver design, it was shown that the pressure drop is a key criterion. However, for recuperated layouts, the combined pressure drop of the recuperator and receiver is more important. In terms of both electricity costs and carbon emissions, the internally-fired recuperated micro gas-turbine was shown to be the most promising solution of the three configurations evaluated. Compared to competing diesel generators, the electricity costs from hybrid solar units are between 10% and 43% lower, while specific CO2 emissions are reduced by 20–35%.

  • 356.
    Aichmayer, Lukas
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Spelling, James
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Laumert, Björn
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Fransson, Torsten
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Micro Gas-Turbine Design for Small-Scale Hybrid Solar Power Plants2013Inngår i: Proceedings of the ASME Turbo Expo 2013. San Antonio, USA. June 3-7, ASME , 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Hybrid solar micro gas-turbines are a promising technology for supplying controllable low-carbon electricity in off-grid regions. A thermoeconomic model of three different hybrid micro gas-turbine power plant layouts has been developed, allowing their environmental and economic performance to be analyzed. In terms of receiver design, it was shown that the pressure drop is a key criterion. However, for recuperated layouts the combined pressure drop of the recuperator and receiver is more important. The internally-fired recuperated micro gas-turbine was shown to be the most promising solution of the three configurations evaluated, in terms of both electricity costs and carbon emissions. Compared to competing diesel generators, the electricity costs from hybrid solar units are between 10% and 43% lower, while specific CO2 emissions are reduced by 20 – 35%.

  • 357.
    Aichmayer, Lukas
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Spelling, James
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Wang, Wujun
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Laumert, Björn
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Design and Analysis of a Solar Receiver for Micro Gas Turbine based Solar Dish Systems2012Inngår i: Proceedings of the International SolarPACES Conference 2012. Marrakesh, Morocco. September 11-14, 2012, 2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The solar receiver is one of the key components of hybrid solar micro gas turbine systems which would seem to present a number of advantages when compared with Stirling engine systems. A solar receiver meeting the specific requirements for integration into the power conversion system of the solar laboratory of the Royal Institute of Technology - which will emulate a solar dish system and is currently under construction - was designed. The simulations that have been performed utilize a heat transfer and pressure drop model coupled with a multi-objective optimizer as well as a coupled-CFD/FEM tool, allowing determination of the ideal receiver design for the expected conditions. The analysis has shown that the use of volumetric solar receivers to provide heat input to micro gas turbine based solar dish systems appears to be a promising solution; with pressurized receiver configurations as the preferred choice due to significant lower pressure drops as compared to atmospheric configurations.

  • 358.
    Aichmayer, Lukas
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Wang, Wujun
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Garrido, Jorge
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Laumert, Björn
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Experimental evaluation of a novel solar receiver for a micro gas-turbine based solar dish system in the KTH high-flux solar simulator2018Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 159, s. 184-195Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work presents the experimental evaluation of a novel pressurized high-temperature solar air receiver for the integration into a micro gas-turbine solar dish system reaching an air outlet temperature of 800°C. The experiments are conducted in the controlled environment of the KTH high-flux solar simulator with well-defined radiative boundary conditions. Special focus is placed on providing detailed information to enable the validation of numerical models. The solar receiver performance is evaluated for a range of operating points and monitored using multiple point measurements. The porous absorber front surface temperature is measured continuously as it is one of the most critical components for the receiver performance and model validation. Additionally, pyrometer line measurements of the absorber and glass window are taken for each operating point. The experiments highlight the feasibility of volumetric solar receivers for micro gas-turbine based solar dish systems and no major hurdles were found. A receiver efficiency of 84.8% was reached for an air outlet temperature of 749°C. When using a lower mass flow, an air outlet temperature of 800°C is achieved with a receiver efficiency of 69.3%. At the same time, all material temperatures remain below permissible limits and no deterioration of the porous absorber is found.

  • 359.
    Aichmayer, Lukas
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Wang, Wujun
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Garrido, Jorge
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Laumert, Björn
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Experimental Flux Measurement of a High-Flux Solar Simulator using a Lambertian Target and a Thermopile Flux Sensor2016Inngår i: AIP Conference Proceedings 1734, American Institute of Physics (AIP), 2016, Vol. 1734, artikkel-id 130001Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A measurement system for the experimental determination of the flux distribution at the focal plane of the KTH high-flux solar simulator was designed and implemented. It is based on a water-cooled Lambertian target and a thermopile flux sensor placed close to the focal point of the solar simulator. Correction factors to account for systematic effects were determined and an uncertainty analysis was performed. The measurement system was successfully used to evaluate the flux distribution of a single lamp/lens-arrangement with a peak flux of 675kW/m².

  • 360.
    Aid, Graham
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekologi.
    Industrial Ecology Methods within Engagement Processes for Industrial Resource Management2013Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The global use of resources such as materials, energy, and water has surpassed sustainable levels by many accounts.  The research presented here was explicitly normative in its aim to improve the understanding of, and make sustainable change toward highly systemic issues of resource management.  The core methods chosen to work toward this aim were bottom up action research procedures (including stakeholder engagement processes) and industrial ecology analysis tools.  These methods were employed and tested in pragmatic combination through two of the author’s case study projects. The first case study, performed between 2009 and 2012, employed a multi-stakeholder process aimed at improving the cycling of construction and demolition waste in the Stockholm region.  The second case study produced a strategic tool (Looplocal) built for facilitating more efficient regional industrial resource networks. While the highly participative aim of the cases required a larger contribution of resources than that of more closed studies, it is arguable that the efficacy of approaching the project aims is improved through their employment. 

    Fulltekst (pdf)
    Aid - Industrial Ecology Methods within Engagement Processes for Industrial Resource Management
  • 361.
    Aid, Graham
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekologi.
    Potential technology for the advanced utilization of construction, demolition, and industrial waste2008Konferansepaper (Fagfellevurdert)
  • 362.
    Aid, Graham
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekologi.
    Brandt, Nils
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekologi.
    Action Research In Waste Management: Application to construction and demolition waste in the Stockholm region2010Inngår i: Linnaeus ECO-TECH ´10 / [ed] Fabio Kaczala, Linnaeus University , 2010, s. 1009-1019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The action research methodology and several of its methods have previously been highlighted and described by the authors as a fitting and rigorous framework approach for complex waste management systems.  This was in response to criticism of the ex ante selection of traditional empiric systems analysis tools to provide decision support and ‘sustainable improvement’ in such complex systems which often involve strong human and political factors.   Several of the action research methods described have recently been utilized in a case study around mineral (aggregate) construction and demolition waste in the Stockholm region.  These methods were integrated through a series of workshops and work areas undergone together with project members from several private and public sectors.  Leaving the problem fuzzy (loosely defined) in the beginning; utilizing convergent interviewing, rich pictures and focus groups allowed the researchers and partner stakeholders to identify not one but several problem areas within the system of focus.  Indicator creation and a dialectic processes were then used to identify qualitative and quantitative aspects of salience around these problem areas.  These resulting indicators were strengthened through a process of verification.  Each indicator was then analyzed by what was deemed to be appropriate and transparent means.  It is argued that this approach may create better communication, transparency, and understanding by the stakeholders.  These factors in turn allowing stronger stakeholder ownership of the process and assisting in more informed decisions and help to provide stability for desired change. However the process was not without its drawbacks such as intense communication and time requirements.

    Fulltekst (pdf)
    Action Research for Waste Management
  • 363.
    Aid, Graham
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekologi.
    Brandt, Nils
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekologi.
    Bygg- och rivningsavfall: Action Research vid KTH2010Inngår i: Återvinnare För Industrin / [ed] Kjell-Arne Larsson, Stockholm: Rekord Media och Produktion AB , 2010Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 364.
    Aid, Graham
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekologi (flyttat 20130630).
    Brandt, Nils
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekologi (flyttat 20130630).
    Improvement of aggregate cycles in Stockholm and the Baltic Region: Activities and results of the BRA initiative2012Inngår i: WASCON 2012 Conference proceedings / [ed] M. Arm, C. Vandecasteele, J. Heynen, P. Suer and B. Lind, 2012, s. 1-9Konferansepaper (Fagfellevurdert)
    Abstract [en]

    From 2009 until 2011 project BRA (Bygg-och Rivningsavfall i Stockholms Län) “Construction and Demolition (C&D) waste in Stockholm County” was coordinated from the division of Industrial Ecology, KTH. This project was focused on actively improving (from plural perspectives) the cycles of C&D (specifically non-metallic inert) materials in the region. In response to the normative aim and inter-systems complexity, a highly participative action research procedure was adopted. Through processes of network communication, workshops, a course, and an international symposium - a number of issues (such as market development, recycled product quality, greenhouse gas impacts, collaborative planning, and statistics) were prioritized, researched, and acted upon. Indicators for measuring progress in selected areas were developed and preliminary action plans created. At a final co-organized symposium Swedish delegates laid the groundwork for the establishment of a Swedish C&D recycling b ranch organization. This initiative of continued collaboration between and within sectors is seen as a vehicle for the priorities and action requirements identified in BRA to be further enabled and held in focus. Furthermore, these actors taking ownership of the process is seen as a success in accordance to the original aims and the need for further cycles of evaluation, planning, and action.

  • 365.
    Aid, Graham
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Industriell ekologi.
    Brandt, Nils
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekologi (flyttat 20130630).
    Lysenkova, Mariya
    Smedberg, Niklas
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Industriell ekologi.
    Looplocal - a heuristic visualization tool to support the strategic facilitation of industrial symbiosis2015Inngår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 98, s. 328-335Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Industrial symbiosis (IS) developments have been differentiated as self-organized, facilitated, and planned. This article introduces a tool, Looplocal, which has been built with objectives to support the strategic facilitation of IS. Looplocal is a visualization tool built to assist in 1) Simplifying the identification of regions susceptible to new industrial symbiosis facilitation activities 2) Enabling proactive and targeted marketing of potential exchanges to key actors in specific regions and 3) Assisting facilitators to assess the various strategies and consequential engagement and analysis methodologies suitable for additional IS development in specific regions. The tool compares industrial symbiosis data and estimated regional material and energy flows (on a facility level) to identify potential IS transfer information along with key stakeholder and network data. The authors have performed a proof of concept run of this tool on Sweden. In its early stages of application the method has given results seen as useful for identifying regions susceptible to the investment of symbiosis facilitators' time and resources. The material focus and customization possibilities for the tool show potential for a spectrum of potential facilitators: from waste management companies to national or regional authorities. In conjunction with long term business models, such a tool might be utilized throughout an adaptive chain of facilitation activities and aims.

  • 366.
    Aid, Graham
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekologi (flyttat 20130630).
    Brandt, Nils
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekologi (flyttat 20130630).
    Lysenkovac, Mariya
    Smedberg, Niklas
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekologi (flyttat 20130630).
    Looplocal: a Heuristic Visualization Tool for the Strategic Facilitation of Industrial Symbiosis2012Inngår i: Greening of Industry Netowrk Proceedings / [ed] Leo Baas, 2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Industrial symbiosis (IS) developments have been differentiated as ‘self organized’, ‘facilitated’, and ‘planned’. This article introduces a tool that has been built with objectives to support the strategic facilitation of IS. ‘Looplocal’ is a visualization tool built to assist in 1) the identification of regions prone to new industrial symbiosis activities 2) market potential exchanges to key actors and 3) assist aspiring facilitators to assess the various strategies and social methodologies available for the initial phases of a facilitated industrial symbiosis venture. This tool combines life cycle inventory (LCI) data, waste statistics, and national industrial data (including geographic, activity, economic, and contact information) to perform a heuristic analysis of raw material and energy inputs and outputs (wastes). Along with an extensive list of ‘waste to raw material’ substitutions (which may be direct, combined, or upgraded) gathered from IS uncovering studies, IS organizations, and waste and energy professionals; heuristic regional output to input ‘matching’ can be visualized. On a national or regional scale the tool gives a quick overview of what could be the most interesting regions to prioritize resources for IS facilitation. Focusing in on a regional level, the tool visualizes the potential structure of the network in that region (centralized, decentralized, or distributed), allowing a facilitator to adapt the networking approach correspondingly. The tool also visualizes potential IS transfer information, along with key stakeholder data. The authors have performed a proof of concept run of this tool in the ‘industrial disperse’ context of Sweden. In its early stages of application, the method has proven capable of identifying regions prone to the investment of facilitators’ resources. The material focus and custom possibilities for the tool show potential for a wide spectrum of potential facilitators: from waste management companies (using the tool as a strategic market analysis tool) to national or regional authorities looking to lower negative environmental impacts, to ‘sustainable’ industry sectors looking to strengthen market positioning. In conjunction with proper long term business models, such a tool could be reusable itself over the evolution of facilitation activities and aims.

  • 367.
    AIDANPÄÄ, MATHILDA
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Integrerad produktutveckling.
    SJÖBERG, MATHILDA
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Integrerad produktutveckling.
    De etiska konsekvenserna av produktutveckling: Oönskade konsekvenser av strävan efter zero-labourfactories2018Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Graden av automatisering sker i allt högre takt idag, vilken drivs av innovationer och produktutvecklingar. Att följa med i denna utveckling är nödvändigt för att företag ska förbli konkurrenskraftiga på marknaden. Introduktion av ny och modern teknik har gjort att frågan om vi nu står inför en fjärde industriell revolution diskuteras flitigt. Begrepp som zero-labour factory blir allt mer använt vid denna tekniska framfart. Huruvida hänsyn tas till det etiska perspektivet vid automatisering och produktutvecklingsprocesser är en fråga som blir mer aktuell.

    Syftet med denna rapport är att utreda hur stor roll det etiska perspektivet har vid beslut om automatisering och vem det etiska ansvaret ligger hos vid automatisering. Utöver detta undersöks även om etik bör integreras i ingenjörsutbildningar och till vilken utsträckning. Utifrån detta har följande frågeställningar har studerats:

    Hur stor är vikten av det etiska perspektivet i beslutsfasen vid automatisering?

    Hos vem ligger det etiska ansvaret för produktutvecklingen?

    I vilken utsträckning borde det etiska perspektivet integreras i utbildningen?

    Metoden som använts under detta arbete är en omfattande litteraturstudie av hur forskningen ser ut i dagsläget. Till det har en kvalitativ studie gjorts genom semistrukturerade intervjuer med personer som är verksamma på företag som har automatiserat sin produktion eller arbetar med att ta fram produkter i automatiseringssyfte på den svenska marknaden.

    Resultatet av studien visar att de producerande företagen strävar efter zero-labour factories och gör sitt yttersta för att ta ansvar för de etiska konsekvenserna som drabbar medarbetarna på grund av det. Trots att det råder en gemensam åsikt om att automatisering kan få oönskade etiska effekter, väljer företagen att integrera produktutvecklingar. Det är effektiviseringar och kostnadsminimeringar som är drivande faktorer, det etiska perspektivet kommer i andrahand. Vidare säger de företag som automatiserar att de tar ett etiskt ansvar för sina medarbetare, men fortsätter med automatiseringsprocesser för att förbli konkurrenskraftiga. Intervjupersonen från det produktutvecklande företag anser sig inte ha något etiskt ansvar för hur teknikutvecklingen påverkar medarbetare hos slutkunden.

    Vidare visar forskning på området att teknikutveckling kan ha oönskade etiska effekter, något som en ingenjör måste ta hänsyn till. Kungliga Tekniska högskolan har idag inte etik som obligatoriskt moment på alla dess program. Personer som intervjuats anser att det bör ingå i utbildningen, vilket även styrks av genomförd litteraturstudie.

    Slutsatser som dragits är att det etiska perspektivet inte väger tungt jämfört med kostnadsbesparingar och effektivisering av produktionen vid beslutsprocesser, att det etiska ansvaret för produktutvecklingen ligger både på det producerande och de produktutvecklande företagen samt till sist att etik bör integreras i utbildningen.

    Fulltekst (pdf)
    fulltext
  • 368.
    Aidanpää, Sandra
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.).
    Nordmark, Elin MK
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.).
    Flexible Updates of Embedded Systems Using Containers2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In this thesis the operating-system-level virtualization solution Docker is investigated in the context of updating an embedded system on application level. An updating sequence is designed, modelled and implemented, on which experiments are conducted to measure uptime and current. Within the popular notion of the Internet of Things, more and more things are being connected to the Internet and there by the possibility of dynamic updates over the Internet is created. Being able to update remotely can be very benecial, as systems may be costly or unpractical to reach physically for software updates. Operating-system-level virtualization, software containers, are a lightweight virtualization solution that can be used for dynamic updating purposes. Virtualization properties, like resource isolation and letting software share hardware capabilities are used in determining the architecture. The container architecture used is a microservice architecture, where systems are composed from many smaller, loosely coupled services. The application area for the results of this thesis are start-ups in the Internet of Things eld, delimited to low complexity systems such as consumer products. The update regime is created with the properties of microservice architectures in mind, creating a self-propelling, self-testing, scalable and seamless dynamic updating process that can be used for systems of dierent complexity. The update regime is modeled to give proof of concept and to help design the implementation. The implemented update regime was made on an ARM based single board computer with a Linux-kernel based operating system running Docker. Experiments were then conducted in order to give a clear indication of the behavior of a dynamically updated embedded system. The experiments showed that the update regime can be seamless, meaning that the uptime properties are not aected by this kind of updating. The experiments also showed that no signicant changes in current can be noted for container limitations during this kind of update.

    Fulltekst (pdf)
    fulltext
  • 369. Aimable, Anne
    et al.
    Doubi, Herve Goure
    Stuer, Michael
    Zhao, Zhe
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Bowen, Paul
    Synthesis and Sintering of ZnO Nanopowders2017Inngår i: TECHNOLOGIES, ISSN 2227-7080, Vol. 5, nr 2, artikkel-id 28Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nanopowders are continuously under investigation as they open new perspectives in numerous fields. There are two main challenges to stimulating their development: sufficient low-cost, high throughput synthesis methods which lead to a production with well-defined and reproducible properties; and for ceramics specifically, the conservation of the powders' nanostructure after sintering. In this context, this paper presents the synthesis of a pure nanosized powder of ZnO (dv(50)similar to 60 nm, easily redispersable) by using a continuous Segmented Flow Tubular Reactor (SFTR), which has previously shown its versatility and its robustness, ensuring a high powder quality and reproducibility over time. A higher scale of production can be achieved based on a "scale-out" concept by replicating the tubular reactors. The sinterability of ZnO nanopowders synthesized by the SFTR was studied, by natural sintering at 900 degrees C and 1100 degrees C, and Spark Plasma Sintering (SPS) at 900 degrees C. The performance of the synthesized nanopowder was compared to a commercial ZnO nanopowder of high quality. The samples obtained from the synthesized nanopowder could not be densified at low temperature by traditional sintering, whereas SPS led to a fully dense material after only 5 min at 900 degrees C, while also limiting the grain growth, thus leading to a nanostructured material.

  • 370. Airiskallio, E.
    et al.
    Nurmi, E.
    Heinonen, M. H.
    Vayrynen, I. J.
    Kokko, K.
    Ropo, M.
    Punkkinen, M. P. J.
    Pitkanen, H.
    Alatalo, M.
    Kollar, J.
    Johansson, Börje
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad materialfysik.
    Vitos, Levente
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad materialfysik.
    High temperature oxidation of Fe-Al and Fe-Cr-Al alloys: The role of Cr as a chemically active element2010Inngår i: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 52, nr 10, s. 3394-3404Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Good high-temperature corrosion resistance of Fe-Al alloys in oxidizing environments is due to the alpha-Al2O3 film which is formed on the surface provided temperature is above 900 degrees C and the Al-content of the alloy exceeds the critical value. Ab initio calculations combined with experiments on Fe-13Al, Fe-18Al, Fe-23Al and Fe-10Cr-10Al alloys show that the beneficial effect of Cr on the oxidation resistance is significantly related to bulk effects. The comparison of experimental and calculated results indicates a clear correlation between the Fe-Cr chemical potential difference and the formation of the protective oxide scales. (C) 2010 Elsevier Ltd. All rights reserved.

  • 371. Airiskallio, E.
    et al.
    Nurmi, E.
    Heinonen, M. H.
    Vayrynen, I. J.
    Kokko, K.
    Ropo, M.
    Punkkinen, M. P. J.
    Pitkanen, H.
    Alatalo, M.
    Kollar, J.
    Johansson, Börje
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad materialfysik.
    Vitos, Levente
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad materialfysik.
    Third element effect in the surface zone of Fe-Cr-Al alloys2010Inngår i: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 81, nr 3Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The third element effect to improve the high temperature corrosion resistance of the low-Al Fe-Cr-Al alloys is suggested to involve a mechanism that boosts the recovering of the Al concentration to the required level in the Al-depleted zone beneath the oxide layer. We propose that the key factor in this mechanism is the coexistent Cr depletion that helps to maintain a sufficient Al content in the depleted zone. Several previous experiments related to our study support that conditions for such a mechanism to be functional prevail in real oxidation processes of Fe-Cr-Al alloys.

  • 372. Airiskallio, E.
    et al.
    Nurmi, E.
    Vayrynen, I. J.
    Kokko, K.
    Ropo, M.
    Punkkinen, M. P. J.
    Johansson, Börje
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad materialfysik.
    Vitos, Levente
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad materialfysik.
    Magnetic origin of the chemical balance in alloyed Fe-Cr stainless steels: First-principles and Ising model study2014Inngår i: Computational materials science, ISSN 0927-0256, E-ISSN 1879-0801, Vol. 92, s. 135-140Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Iron-chromium is the base material for most of the stainless steel grades. Recently, new insights into the origins of fundamental physical and chemical characteristics of Fe-Cr based alloys have been achieved. Some of the new results are quite unexpected and call for further investigations. The present study focuses on the magnetic contribution in the atomic driving forces related to the chemical composition in Fe-Cr when alloyed with Al, Ti, V, Mn, Co, Ni, and Mo. Using the ab initio exact muffin-tin orbitals method combined with an Ising-type spin model, we demonstrate that the magnetic moment of the solute atoms with the induced changes in the magnetic moments of the host atoms form the main factor in determining the mixing energy and chemical potentials of low-Cr Fe-Cr based alloys. The results obtained in the present work are related to the designing and tuning of the microstructure and corrosion protection of low-Cr steels.

  • 373. Airiskallio, E.
    et al.
    Nurmi, E.
    Vayrynen, I. J.
    Kokko, K.
    Ropo, M.
    Punkkinen, Marko P. J.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad materialfysik.
    Johansson, Börje
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad materialfysik.
    Vitos, Levente
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad materialfysik.
    Tuning the surface chemistry of Fe-Cr by V doping2009Inngår i: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 80, nr 15Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The reversal of the magnitudes of the bulk and surface chemical-potential differences induces the outburst of Cr on the otherwise pure Fe surface of Fe-Cr alloys. This threshold value for the Cr content is about 10 at. %. It is found that vanadium addition to Fe-Cr shifts the Cr threshold to a substantially lower value suggesting V having a positive effect on the corrosion resistance of low Cr steels. The obtained shift in the Cr threshold is shown to be connected to the change in volume of the alloy.

  • 374.
    Ajani, Altinay
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Karaömer, Ahmed
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Hur samlar Skanska in information vid kalkylering?2010Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    I dagens industrisamhälle anses projektarbete som den självklara modellen för utvecklingsarbete. Första steget i projekt där information spelar en väsentlig roll är vid kalkylering . Det är här projektets framtid avgörs. Här gäller det att vara tydlig med den information som sammanställs samt lagra den för effektiv åtkomst för projektmedlemmarna. Utan ett väl fungerande informationsflöde får organisationen svårt att anpassa sig till förändringar samt problem som uppstår. Syftet med denna studie är att undersöka hur kalkylering sker i teorin och i praktiken för att få en förståelse för hur informationsflödena spelar sin roll. Den teoretiska referensramen baserades på de teorier som påträffades vid en sökning bland KTHB:s databaser samt Google Scholar. Informationsflödet har delats upp i tre delar, presentation, transport och lagring av information. Dessutom studeras ett antal olika kalkylmetoder. För att få en kompletterande bild av hur detta applicerats i praktiken har en fallstudie utförts på Skanska Sverige AB. Denna studie omfattar tre intervjutillfällen samt en kontinuerlig kontakt med en inköpsansvarig på Skanska. Kalkylmetoderna som undersöktes var ABC – kalkylering, produktkalkylering och produktionskalkylering. Sedan undersöktes vilka av dessa kalkylmetoder som används på Skanska Sverige AB. Kalkyler upprättas utifrån företagets informationshanteringssystem och Skanska använder sig av ett eget utvecklat system, Spik. Vidare undersöktes vilken typ av information som har störst påverkan vid kalkylens utformning och vilka faktorer som är avgörande. Teoristudierna jämförs med empirin genom diskussion om informationsflödets betydelse vid kalkylframtagning på Skanska. Därefter diskuteras rekommendationer om hur informationsflödet skulle kunna förbättras vid framtagningen av kalkylen.

    Fulltekst (pdf)
    fulltext
  • 375.
    Ajmal Khan, Muhammad
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Raza, Rizwan
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Bohn Lima, Raquel
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik. KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Chaudhry, M. Asharf
    Ahmed, E.
    Abbas, Ghazanfar
    Comparative study of the nano-composite electrolytes based on samaria-doped ceria for low temperature solid oxide fuel cells (LT-SOFCs)2013Inngår i: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 38, nr 36, s. 16524-16531Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ceria-based electrolyte materials have great potential in low and intermediate temperature solid oxide fuel cell applications. In the present study, three types of ceria-based nanocomposite electrolytes (LNK-SDC, LN-SDC and NK-SDC) were synthesized. One-step co-precipitation method was adopted and different techniques were applied to characterize the obtained ceria-based nano-composite electrolyte materials. TGA, XRD and SEM were used to analyze the thermal effect, crystal structure and morphology of the materials. Cubic fluorite structures have been observed in all composite electrolytes. Furthermore, the crystallite sizes of the LN-SDC, NK-SDC, LNK-SDC were calculated by Scherrer formula and found to be in the range 20 nm, 21 nm and 19 nm, respectively. These values emphasize a good agreement with the SEM results. The ionic conductivities were measured using EIS (Electrochemical Impedance Spectroscopy) with two-probe method and the activation energies were also calculated using Arrhenius plot. The maximum power density was achieved 484 mW/cm(2) of LNK-SDC electrolyte at 570 degrees C using the LiCuZnNi oxide electrodes.

  • 376.
    Akbarnejad, Shahin
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Experimental and Mathematical Study of Incompressible Fluid Flow through Ceramic Foam Filters2016Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Ceramic Foam Filters (CFFs) are widely used to filter solid particles and inclusions from molten metal in metal production, particularly in the aluminum industry. In general, the molten metal is poured on the top of a ceramic foam filter until it reaches a certain height, also known as metal head or gravity head. This is done to build the required pressure to prime the filter media and to initiate filtration. To predict the required metal head, it is necessary to obtain the Darcy and non-Darcy permeability coefficients of the filter. The coefficients vary upon filter type. Here, it is common to classify CFFs based on grades or pore per inches (PPI). These CFFs range from10 to100 PPI and their properties vary in everything from cell and window size to strut size. The 80-100 PPI CFFs are generally not practical for use by industry, since the priming of the filters by a gravitational force requires an excessive metal head. However, recently a new method has been developed to prime such filters by using electromagnetic Lorentz forces. This allows the filters to be primed at a low metal head.

    To continue the research work, it was deemed necessary to measure the pressure gradients of single and stack of commercial alumina ceramic foam filters and to obtain the permeability characteristics. Therefore, efforts have been made to validate the previously obtained results, to improve the permeametry experimental setup, and to obtain Darcy and non-Darcy permeability coefficients of single 30, 50, and 80 PPI filters and stacks of filters. Furthermore, the experimentally obtained pressure gradients were analyzed and compered to the mathematically and analytically estimated pressure gradients.

    The studies showed that, in permeametry experiments, the sample sealing procedure plays an important role for an accurate estimation of the permeability constants. An inadequate sealing or an un-sealed sample results in an underestimation of the pressure drop, which causes a considerable error in the obtained Darcy and non-Darcy permeability coefficients. Meanwhile, the results from the single filter experiments showed that the permeability values of the similar PPI filters are not identical. However, the stacks of three identical filters gave substantially the same measured pressure drop values and roughly the same Darcy and non-Darcy coefficients as for the single filters.

    The permeability coefficients of the filters are believed to be best defined and calculated by using the Forchheimer equation. The well-known and widely used Ergun and Dietrich equations cannot correctly predict the pressure drop unless a correction factor is introduced. The accuracy of the mathematically estimated pressure drop, using COMSOL Multiphysics® 5.1, found to be dependent on the drag term used in the Brinkman-Forchheimer equation.  Unacceptable error, as high as 84 to 89 percent for the 30, 50 and 80 PPI single filters, compared to the experimentally obtained pressure gradient values were observed when the literature defined Brinkman-Forchheimer drag term was used. However, when the same second order drag term (containing the non-Darcy coefficient) as defined in the Forchheimer equation was used, the predicted pressure gradient profiles satisfactorily agreed with the experiment data with as little as 0.3 to 5.5 percent deviations for the 30, 50 and 80 PPI single filters.

    Fulltekst (pdf)
    Thesis
  • 377.
    Akbarnejad, Shahin
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Investigation on static strength of welded joints2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Although high strength steels represent yield strength up to 1300 MPa, welded structures reveal lowerstrength values. The strongest commercially available electrode provides the yield strength of about900 MPa. Therefore, in welded steels with strength above this type of filler metal, achieving anacceptable global strength is a crucial issue.

    In this master thesis, affects of different welding procedures on static strength of welded jointsof Weldox 960 and Weldox 1100 steels, were studied. These steels are produced by SSAB inOxelösund. Meanwhile, finite element method analyses were applied in order to investigatethe static strength behavior of such weldments under uniaxial tension.

    The welding parameters which were selected as variables are:

    •  Heat input
    • Weld joint geometry
    • Filler metal

    When weld metal is undermatching in strength levels than the base material, by applyingtension the soft weld metal begins to deform before parent metal. At that point thedeformation of resulted soft zone, including the weld metal and the heat affected zone, ishindered by high strength parent metal. Thus, uniaxial stress caused by uniaxial load isconverted to multiaxial stress. This conversion in tension results in increase in the staticstrength of weldment. The increase in strength is emphasized by increase in the width of thewelded joint while the thickness of the plate is kept as constant.

    After experiments and performing FEM studies, it was revealed that the static strength ofWeldox 960 welded joints approaches towards the tensile strength of parent metal by increasein the width of the weldment. In Weldox 1100 joints; a slight increase in tensile properties ofthe weldments, when the width of the sample increases, was observed.

    Fulltekst (pdf)
    Investigation on static strength of welded joints
  • 378.
    Akbarnejad, Shahin
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Jonsson, Lage
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Kennedy, M. W.
    Aune, R. E.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Analysis on Experimental Investigation and Mathematical Modelling of Incompressible Flow through Ceramic Foam FiltersManuskript (preprint) (Annet vitenskapelig)
  • 379.
    Akbarnejad, Shahin
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jonsson, Lage Tord Ingemar
    Kennedy, Mark William
    Aune, Ragnhild Elizabeth
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Analysis on Experimental Investigation and Mathematical Modeling of Incompressible Flow Through Ceramic Foam Filters2016Inngår i: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 47, nr 4, s. 2229-2243Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents experimental results of pressure drop measurements on 30, 50, and 80 pores per inch (PPI) commercial alumina ceramic foam filters (CFF) and compares the obtained pressure drop profiles to numerically modeled values. In addition, it is aimed at investigating the adequacy of the mathematical correlations used in the analytical and the computational fluid dynamics (CFD) simulations. It is shown that the widely used correlations for predicting pressure drop in porous media continuously under-predict the experimentally obtained pressure drop profiles. For analytical predictions, the negative deviations from the experimentally obtained pressure drop using the unmodified Ergun and Dietrich equations could be as high as 95 and 74 pct, respectively. For the CFD predictions, the deviation to experimental results is in the range of 84.3 to 88.5 pct depending on filter PPI. Better results can be achieved by applying the Forchheimer second-order drag term instead of the Brinkman-Forchheimer drag term. Thus, the final deviation of the CFD model estimates lie in the range of 0.3 to 5.5 pct compared to the measured values.

  • 380.
    Akbarnejad, Shahin
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Kennedy, M. W.
    Fritzsch, R.
    Aune, R. E.
    An investigation on permeability of ceramic foam filters (CFF)2015Inngår i: TMS Light Metals, 2015, s. 949-954Konferansepaper (Fagfellevurdert)
    Abstract [en]

    CFFs are used to filter liquid metal in the aluminum industry. CFFs are classified in grades or pores per inch (PPI), ranging from 10-100 PPI. Their properties vary in everything from pore and strut size to window size. CFFs of 80-100 PPI are generally not practical for use by industry, as priming of the filters by gravitational forces requires an excessive metal head. Recently, co-authors have invented a method to prime such filters using electromagnetic Lorentz forces, thus allowing filters to be primed with a low metal head. In the continuation of this research work, an improved experimental setup was developed in the present study to validate previous results and to measure the permeability of different filters, as well as a stack of filters. The study of permeability facilitates estimation of the required pressure drop to prime the filters and the head required to generate a given casting rate.

  • 381.
    Akbarnejad, Shahin
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Jonsson, Lage
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Jönsson, Pär
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad processmetallurgi.
    Significance of Fluid Bypassing Effect on Darcy and Non-Darcy Permeability Parameters of Ceramic Foam FiltersManuskript (preprint) (Annet vitenskapelig)
  • 382.
    Akbarnejad, Shahin
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Saffari Pour, Mohsen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jonsson, Lage Tord Ingemar
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Jönsson, Pӓr Göran
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Effect of Fluid Bypassing on the Experimentally Obtained Darcy and Non-Darcy Permeability Parameters of Ceramic Foam Filters2017Inngår i: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 48, nr 1, s. 197-207Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ceramic foam filters (CFFs) are used to remove solid particles and inclusions from molten metal. In general, molten metal which is poured on the top of a CFF needs to reach a certain height to build the required pressure (metal head) to prime the filter. To estimate the required metal head, it is necessary to obtain permeability coefficients using permeametry experiments. It has been mentioned in the literature that to avoid fluid bypassing, during permeametry, samples need to be sealed. However, the effect of fluid bypassing on the experimentally obtained pressure gradients seems not to be explored. Therefore, in this research, the focus was on studying the effect of fluid bypassing on the experimentally obtained pressure gradients as well as the empirically obtained Darcy and non-Darcy permeability coefficients. Specifically, the aim of the research was to investigate the effect of fluid bypassing on the liquid permeability of 30, 50, and 80 pores per inch (PPI) commercial alumina CFFs. In addition, the experimental data were compared to the numerically modeled findings. Both studies showed that no sealing results in extremely poor estimates of the pressure gradients and Darcy and non-Darcy permeability coefficients for all studied filters. The average deviations between the pressure gradients of the sealed and unsealed 30, 50, and 80 PPI samples were calculated to be 57.2, 56.8, and 61.3 pct. The deviations between the Darcy coefficients of the sealed and unsealed 30, 50, and 80 PPI samples found to be 9, 20, and 31 pct. The deviations between the non-Darcy coefficients of the sealed and unsealed 30, 50, and 80 PPI samples were calculated to be 59, 58, and 63 pct.

  • 383.
    Akeyo Forsman, Prisca
    KTH, Skolan för industriell teknik och management (ITM), Tillämpad maskinteknik (KTH Södertälje).
    A Study of Construction Project Stakeholders’ Management Methods and the Critical Success Factors Essential for Successful Management in Stockholm Region.2017Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Fulltekst (pdf)
    fulltext
  • 384.
    Akhlagi, Ali
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    A Modelica-based framework for modeling and optimization of microgrids2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Microgrids have lately drawn much attention due to their considerable financial benefits and the increasing concerns about environmental issues. A solution that can address different engineering problems - from design to operation - is desired for practical reasons and to ensure consistency of the analyses. In this thesis, the capabilities of a Modelicabased framework is investigated for various microgrid optimization problems. Various sizing and scheduling problems are successfully formulated and optimized using nonlinear and physical component models, covering both electrical and thermal domains. Another focus of the thesis is to test the optimization platform when varying the problem formulation; performance and robustness tests have been performed with different boundary conditions and system setups. The results show that the technology can effectively handle complex scheduling strategies such as Model Predictive Control and Demand Charge Management. In sizing problems, although the platform can efficiently size the components while simultaneously solving for the economical load dispatch for short horizons (weekly or monthly), the implemented approach would require adaptations to become efficient on longer horizons (yearly).

    Fulltekst (pdf)
    fulltext
  • 385.
    Akhtar, Shahid
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processvetenskap.
    Shaikh, Md. Robiul Haque
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processvetenskap.
    Aune, Ragnhild E.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Materialens processvetenskap.
    Micro Porosity Development in Directionally Solidified A356 Castings Doped with Anodized Plates and Sintered Aluminium2011Inngår i: European Congress and Exhibition on Advanced Materials and Processes (EUROMAT) 2011, Symposium C52: Processing and characterizing techniques, 2011Konferansepaper (Fagfellevurdert)
  • 386.
    Akhtar, Suleman
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Material Factors Influencing Crack Initiation and Propagation During Seamless Tube Rolling of Low Carbon Steel Grades2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Lower hot ductility can lead to cracks in steels. Hot ductility is affected by grain boundary sliding at temperatures higher than A3 and by the presence of thin films of ferrite at grain boundaries at temperatures lower than A3. Grain boundary sliding might occur because of the segregation of harmful elements like sulphur, etc. While thin films of ferrite at grain boundaries lead to easy interlinking of MnS precipitates at grain boundaries and ultimately may cause cracks in the material. Also, stress concentration is higher at thin ferrite films at grain boundaries which for being softer as compared to austenite matrix lead to cracks in the material. Elongated  (Fe, Mn)S sulphides are more detrimental for the hot ductility as compared to round ones. Higher aspect ratio of the precipitates is also dependent on sulphur content. The higher the sulphur content, the higher would be the hot ductility. Silicon, being a ferrite stabilizer, causes the volume fraction of ferrite to increase which improves the hot ductility of the steels. Hot ductility can be improved by adding Boron that segregates to grain boundaries instead of sulphur improving the strength of grain boundaries. Increasing silicon content can lead to higher volume fraction of ferrite thus improving ductility because stress would uniformly be distributed across the grain and not merely on the grain boundaries. Apart from that, decreasing the solution treatment temperature and increasing holding time on solution treatment temperature can lead to lower dissolved content of sulphur and coarser MnS precipitates hence improving hot ductility. 

  • 387.
    Akhter, Tasmiah
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Mohsin, Mael
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Lean produktion i två olika branscher: - En jämförelse mellan sjukvård och industri2014Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Sammanfattning

    Lean produktion är ett välkänt begrepp inom industrin som strävar efter resurseffektivitet och förbättringsarbete med kunden i fokus. Inom lean produktion finns flertal metoder och filosofier att beakta och detta arbete behandlar 5S-metoden, sju plus en slöserierna och allas engagemang i en organisation. Framgångarna med lean produktion inom industrin har lett till att det har implementerats i flera olika branscher, inte minst sjukvården. Denna implementering har mötts av varierande åsikter.

    Syftet med denna rapport är att undersöka om implementeringen av lean produktion inom sjukvården kan bli lika effektiv som inom industrin. Implementeringen av lean inom sjukvården har till viss del visat sig vara framgångsrikt, men oftast uppnås inte uppsatta mål. Med hjälp av tre underfrågor ska frågeställningen besvaras: Kan tillämpningen av lean produktion bli lika effektiv inom sjukvården som industrin?

    Med hjälp av studiebesök och intervjuer från sjukvård och industri kommer empiri samlas för att få förståelse kring hur tillämpningen ser ut idag. Karolinska Universitetssjukhuset i Huddinge står för sjukvårdens empiri och Scania står för industrins empiri. Efter dessa intervjuer skapas en jämförelse mellan sjukvården och industrin och en poängsättning görs för att se hur väl branscherna uppfyller lean produktion enligt teorin.

    Jämförelsen mellan sjukvård och industrin resulterade i att sjukvården kan bli lika effektiv som industrin med dess tillämpning av lean produktion. Detta eftersom effektiviseringspotential sågs i majoriteten av stegen i de berörda metoderna. I åtta av tio steg finns utrymme för effektivisering, där sjukvården kan tillämpa lean lika väl som industrin.

    Fulltekst (pdf)
    fulltext
  • 388.
    AKHTER, TASMIAH
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekonomi och organisation (Inst.).
    ÅKERLIND, TOBIAS
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekonomi och organisation (Inst.).
    Agile IT Infrastructure Transformation: A Case Study of a Nordic Incumbent Telco2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In a growing digital economy, where demands for network services and competition from various communication-over-the-network service providers intensify, telecommunication companies need to keep up in an ever-changing environment. As there is a need to reduce time-to-market for new network services, agility becomes restrained by having to operate within large legacy IT infrastructure environments. While agile methodologies in modern time have attained recognition in the field of software development for the way they help to manage changing customer demands and deliver early value incontinuous increments, it is yet uncertain how agile methodologies can best be adopted for IT infrastructure deliveries to achieve the same purpose. Hence, this study explores how legacy IT infrastructure can be transformed in an agile way into modernized infrastructure landscapes supporting the business with fast enough development, release and deployment of new network services in demand. More precisely, the study investigates how larger IT infrastructure transformation projects can be executed by the help of agile practices. In order to investigate this, the study carries out a case study at Telia Company, a large Nordic incumbent telecommunications company possessing a big legacy of IT infrastructure. The study conducts internal interviews with Telia employees as well as external interviews with agile experts. Also, benchmarking is conducted with a well-established Swedish bank to better understand the challenges and how agile practices can best be applied.The study concludes that agile practices influenced by agile frameworks Scrum and Kanban can advantageously be applied at team level for more agile execution. However, the surrounding organizational business landscape greatly sets the limits for agile deliveries, due to dependencies on cooperation from the business side in the execution phase and the need to be aligned with business needs and stakeholder requirements. Further, the study also shows that the application of agile practices at team level in combination with a close dialogue with stakeholders and a scaled agile approach requiring investing in automation, is the key for more agile infrastructure deliveries. In this way, aligned end-to-end delivery processescan be better developed and infrastructure needs better understood and implemented at the right time. As a contribution, the study proposes a model with inspiration from agile frameworks Scrum, Kanban and SAFe, for how this may work in practice.

    Fulltekst (pdf)
    fulltext
  • 389.
    Akillioglu, Hakan
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    Demand Responsive Planning: A dynamic and responsive planning framework based on workload control theory for cyber-physical production systems2015Doktoravhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    Recent developments in the area of Cyber-Physical Production Systems prove that high technology readiness level is already achieved and industrialization of such technologies is not far from today. Although these technologies seem to be convenient in providing solutions to environmental uncertainties, their application provides adaptability only at shop floor level. Needless to say, an enterprise cannot reach true adaptability without ensuring adaptation skills at every level in its hierarchy. Commonly used production planning and control approaches in industry today inherit from planning solutions which are developed in response to historical market characteristics. However, market tendency in recent years is towards making personalized products a norm. The emerging complexity out of this trend obliges planning systems to a transition from non-recurring, static planning into continuous re-planning and re-configuration of systems. Therefore, there is a need of responsive planning solutions which are integrated to highly adaptable production system characteristics.

    In this dissertation, Demand Responsive Planning, DRP, is presented which is a planning framework aiming to respond to planning needs of shifting trends in both production system technologies and market conditions. The DRP is based on three main constructs such as dynamicity, responsiveness and use of precise data. These features set up the foundation of accomplishing a high degree of adaptability in planning activities. By this means, problems from an extensive scope can be handled with a responsive behavior (i.e. frequent re-planning) by the use of precise data. The use of precise data implies to execute planning activities subject to actual demand information and real-time shop floor data. Within the context of the DRP, both a continuous workload control method and a dynamic capacity adjustment approach are developed. A test-bed is coded in order to simulate proposed method based on a system emulation reflecting the characteristics of cyber-physical production systems at shop floor level.

    Continuous Precise Workload Control, CPWLC, method is a novel approach aiming at precise control of workload levels with the use of direct load graphs. Supported by a multi-agent platform, it generates dynamic non-periodic release decisions exploiting real time shop floor information. As a result, improved shop floor performances are achieved through controlling workload levels precisely by the release of appropriate job types at the right time.

    Presented dynamic capacity adjustment approach utilizes rapid re-configuration capability of cyber-physical systems in achieving more frequent capacity adjustments. Its implementation architecture is integrated to the CPWLC structure. By this means, a holistic approach is realized whereby improved due date performance is accomplished with minimized shop floor congestion. Hence, sensitivity to changing demand patterns and urgent job completions is improved.

    Fulltekst (pdf)
    fulltext
  • 390.
    Akillioglu, Hakan
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    Evolvable Production Systems: Demand Responsive Planning2011Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Dynamic and unforeseeable characteristic of the current market and production environment is not feasible to be met through pre-set parameters being dependent on the predictions. Handling this matter requires to keep focus on production system adaptability. Evolvable Production System has achieved fully system reconfigurability through process oriented modularity and multi agent based distributed control system architecture. One of the essential enhancements provided by EPS on the shop floor is achieving minimized/eliminated system setup time in response to changing product requirements.

    Manufacturing planning and control system, on the other hand, follows hierarchical principles which are quite much reliant on the predicted information so to structure production and planning environment on it. Production system limitations, such as lack of adaptability in response to changing conditions, are in fact influencing the planning system to be structured on the predictions. The enhancements which are ensured by the architecture of EPS enable to relax the constraints on planning system which are imposed by the limitations of production system. These enhancements have an effect at different levels in the planning hierarchy. On the light of these improvements, the planning framework as it is used so far in the industry becomes invalid and this arise a requirement for planning system structure to be designed according to a fully reconfigurable system to be able to benefit such a production system by all means.

    This thesis targets to enlighten the relation between the production system characteristics and planning system structure by emphasizing the planning problems and proposing a planning reference architecture solution to be able achieve a responsive planning framework.

    Fulltekst (pdf)
    fulltext
  • 391.
    Akillioglu, Hakan
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Dias-Ferreira, Joao
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Maffei, Antonio
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Neves, Pedro
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Onori, Mauro
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Continuous precise workload control method2014Inngår i: IEEE International Conference on Industrial Engineering and Engineering Management, 2014, s. 511-515Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The diversity of requirements and the frequency of change in the market can only be competed with dynamicity and responsiveness in both production and planning systems. In this sense, working principles of a novel workload control method, called continuous precise workload control are presented in this paper. The implementation of the method is based on a multi-agent based architecture. The presented approach generates dynamic non periodic release decisions exploiting real time shop floor information. The performance of the system and correlation of norm value against the assessment range are investigated through an experimented test case.

  • 392.
    Akillioglu, Hakan
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    Dias-Ferreira, Joao
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    Onori, Mauro
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    Characterization of Continuous Precise Workload Control and Analysis of Idleness Penalty2014Inngår i: CIE 44 and IMSS14 proceedings, 2014, s. 1998-2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The variability in the market conditions is growing in terms of its frequency of change and range of diversity. In response to this new industrial panorama, research on production systems is aiming to achieve truly reconfigurable shop floors. Frequent changes in such systems require also frequent re-planning with updated information. In this regard the Continuous Precise Workload Control method, is a recent approach aiming at precise control of workload in the shop floor with the use of direct load graphs. Supported by a multi-agent platform, it generates dynamic non-periodic release decisions exploiting real time shop floor information. The study in this paper is two folded; (1) in order to highlight its distinctive characteristics, the presented workload approach is defined in terms of eight dimensions of the workload control concept and (2) the penalty of idleness which affects the decision of release is analyzed by an experiment design in order to investigate its correlation with two critical parameters, norm value and assessment range. The results show that the idleness penalty factor decreases the idleness of the resources up to a point where the adverse effect is initiated. Besides there are strong indications towards the correlation of idleness penalty factor with the norm value.

  • 393.
    Akillioglu, Hakan
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Dias-Ferreira, João
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Onori, Mauro
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Characterization of continuous precise workload control and analysis of idleness penalty2016Inngår i: Computers & industrial engineering, ISSN 0360-8352, E-ISSN 1879-0550, Vol. 102, s. 351-358Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The variability in the market conditions is growing in terms of its frequency of change and range of diversity. In response to this new industrial panorama, research on production systems is aiming to achieve highly reconfigurable shop floors. Frequent changes in such systems require also frequent re-planning with updated information. In this regard the Continuous Precise Workload Control method, is a recent approach aiming at precise control of workload in shop floor with the use of direct load graphs. Supported by a multi-agent platform, it generates dynamic non-periodic release decisions exploiting real time shop floor information. The study in this paper is two folded; (1) the presented workload approach is defined in terms of eight dimensions of the workload control concept in order to highlight its distinctive characteristics and (2) the impact of idleness penalty factor is analyzed by an experiment design in order to investigate its effect on the job release decision. The results show that the idleness penalty factor decreases the idleness of the resources up to a point where the adverse effect is initiated.

  • 394.
    Akillioglu, Hakan
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    Ferreira, Joao
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    Onori, Mauro
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    Demand responsive planning: workload control implementation2013Inngår i: Assembly Automation, ISSN 0144-5154, E-ISSN 1758-4078, Vol. 33, nr 3, s. 247-259Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose – Evolvable production systems enable fully reconfiguration capabilities on the shop floor through process-oriented modularity and multiagent-based distributed control. To be able to benefit architectural and operational characteristics of evolvable systems, there is a need of a newplanning approach which links shop floor characteristics and planning operations. This paper seeks to address these issues.

    Design/methodology/approach – Evolvable production system has a structured methodology in itself. Consistent to this, a reference planningarchitecture is developed aiming to achieve agility on planning activities. Besides a workload control method is proposed and implemented as a part ofthe planning architecture.

    Findings – First applications of evolvable systems have been implemented through European research projects. Shop floor working principles andarchitectural characteristics are consistent to facilitate more agility on planning activities which are framed at a planning reference architecture calleddemand responsive planning. As an implementation case, an agent-based workload control method is proposed and implemented. The characteristicsof EPS and proposed planning architecture enable continuous and dynamic workload control of the shop floor to be implemented.

    Originality/value – This paper presents a new planning model compatible with evolvable production systems targeting to agility to demand onplanning and control activities benefiting shop floor enhancements of a fully reconfigurable system which enables to relax constraints imposed fromproduction systems to planning. In addition, a continuous and dynamic workload control method is proposed and implemented.

  • 395.
    Akillioglu, Hakan
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    Maffei, Antonio
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    Neves, Pedro
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    Ferreira, Joao
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    Operational characterization of evolvable productionsystems2012Inngår i: 4th CIRP Conference on Assembly Technologies and Systems – CATS 2012, 2012, s. 85-90Konferansepaper (Fagfellevurdert)
    Abstract [en]

    On the way to achieve mass customization production systems have to obtain the capability of rapid reconfiguration of not only physical components but also from control point of view. Evolvable Production System targets highly adaptable mechanical and control solutions that can enhance reusability and interoperability of modules, enabling lifetime extension of the modules. The focus of EPS paradigm is to achieve overall system adaptability by autonomous modules which are dedicated to specific processes with the capability of short deployment time at shop floor without reprogramming effort. From the operational point of view EPS brings significant enhancements considering shop floor dynamics and performances therefore positioning of EPS principles and approaches in production system typology from different perspectives is essential. This has been done by two means which are process flow structure and customer order decoupling point location.

  • 396.
    Akillioglu, Hakan
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    Neves, Pedro
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    Onori, Mauro
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    Evolvable Assembly Systems: Mechatronic Architecture Implications and Future Research2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The balance between assembly process optimality and their system’s ability to adapt to new requirements is a key to success for assembly companies. To increase SME’s survivability, an effective methodology is needed to handle the requirements of both agility and mass customization. Evolvable Assembly Systems (EAS) paradigm is a next generation assembly systems focused on these issues. Three key issues are here in focus: process-oriented approach, fine modular granularity, and module intelligence through lighter multi-agent technology at the shop floor level. These issues

    Fulltekst (pdf)
    FULLTEXT01
  • 397.
    Akillioglu, Hakan
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    Onori, Mauro
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    Evolvable production systems and impacts on production planning2011Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Production planning and control strategies have been changing in line with the constant change on product and customer requirements, under the light of technological and scientific advancements. Production systems which are based on mass production became obsolete in time hence companies, being profit oriented, are in need of new solutions towards mass customization to handle rapidly changing market conditions. To deal with this issue, production systems and production planning strategies have to be complementing each other. In this paper Evolvable Production Systems and its compatibility to Just in Time (JIT) Production compared to Material Requirement Planning (MRP) will be discussed.

  • 398.
    Aktas, Meryem
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Tillämpad maskinteknik (KTH Södertälje).
    Anslin, Anslin
    KTH, Skolan för industriell teknik och management (ITM), Tillämpad maskinteknik (KTH Södertälje).
    Analys och utveckling avverifieringsenhet för säker kontakteringvid kalibrering av RRUS.2014Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Fulltekst (pdf)
    fulltext
  • 399.
    Aktas, Stefanos
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Integrerad produktutveckling.
    Wennhall, Thomas
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Integrerad produktutveckling.
    AI - an Untapped Opportunity for Innovation Developing a Screening Tool for AI and Innovation2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    It is known that innovation enables companies to penetrate new markets and achieve higher margins and that technology can contribute to achieving a competitive ad-vantage and growth for organizations. A technology that has as of recently grown to become relevant for organizations is Artificial Intelligence (AI). Even so, previous studies have expressed the difficulty of implementing AI, which motivated this study.

    The main purpose of this study was to develop and test a screening tool that will work as a support in increasing an organization’s utilization of AI and innovation capability. During the course of the study, a great amount of focus was also put into conducting a preliminary analysis in preparation for a larger study that will be dependent on gathering large amounts of quantitative data.

    The research took on a three-phase-process. The first phase focused on gaining basic knowledge in regards to AI, innovation, technology management and model development. The findings in the first phase helped to formulate proper research questions that were applicable to the study.

    After that, the study moved on to the second phase which focused on a more in-depth literature study. This then led on to the development of an appropriate questionnaire for investigating factors that are relevant for AI and innovation, and an assessment model that would be connected to the questionnaire. The questionnaire was used for gathering responses that would be beneficial for the preliminary analysis in the form of a pilot study. The questionnaire and the assessment model together form a screening tool that gives a visual output of an organization’s position in regards to AI and innovation.

    The third and final phase included testing of the created screening tool, analyzing the findings from the pilot study and drawing conclusions from both the developed screening tool, and the results from the pilot study.

    The result from the literature study was the screening tool which takes five di-mensions into consideration that shows relevance to AI and innovation. These di-mensions are Structures, Resources, Methods, Action and Business,eachcontaining areas that exist in organizations that can be adjusted for the sake of the implemen-tation of AI and improvement of innovation management. The screening tool was tested on two separate organizations and managed to reflect these organizations’ AI progress through the assessment model. The screening tool was also applied to the pilot study which resulted in giving indications of what to expect when conducting a larger quantitative study.

    Despite the results gained from this study, it showed that further tests and studies need to be made in order to obtain more viable results. This study will act as a guideline for future studies to attain those results.

    Fulltekst (pdf)
    fulltext
  • 400.
    Akter, Nasrin
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Energi och klimatstudier, ECS.
    Energy Need Assessment and Preferential Choice Survey o fMatipukur Village in Bangladesh: Energy Need Assessment and Preferential Choice Survey of Rural People in Bangladesh2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The aim of this study is to perform a baseline energy survey to understand the existing energy demand and usepattern and to verify the feasibility of a small scale poly-generation project supported by renewable sources ofenergy (biogas based) in a rural area of Bangladesh. A poly-generation solution shall provide multiple outputservices of clean gas, electricity and arsenic free water supply. The project requires using animal dung oragricultural waste to produce biogas and electric energy. The study has analyzed the demand of domesticenergy and water of the village named ‘Matipukur’ in the Jessore district in Bangladesh. The study alsoconsidered available biomass feedstock and energy potential surrounding the village area, as well as the socioeconomicstatus of villagers. The case study included a door to door survey to collect relevant information.Three different economic groups in terms of income scale were investigated throughout the study to obtainbetter insight of the energy-water access situation, requirements and related problems in the village.

    Almost 98% household of this village relies on biomass for energy due to limited access of modern fuel. Thevillage has various biomass potential in the form of animal dung, fuel wood and agricultural waste which can beused for cooking or serve as the basis for other energy carriers. Kerosene is used for lighting. Among thedifferent fuels, dung meets about 44% of the total demand. The contribution of other fuels for domestic use is24% firewood, 22% agricultural waste, and 2% kerosene. The analytical observation found that the annualaverage energy demand of the village is 8.45 GJ per capita. The share of average demand for cooking and3lighting energy is 8.24 GJ per person/year and 0.21 GJ per person/year respectively. The energy consumptionvaries within different income groups. This study has examined the income per capita, family size, education,agricultural land holding per capita, priorities of their annual expenditure etc. which have direct influence onthe fuel consumption pattern of the household. It could be observed that expenses on energy changes as theincome level increases. About awareness of biogas opportunities and willingness to provide feedstock for apoly generation project, the majority of households answered positively, that is, indicating that they wouldcontribute. Educated respondents showed more positive attitude. Regarding changing of traditional cooking,about 95% of the respondents want to change to a more efficient and reliable cooking system to avoid healthand environmental problems associated with indoor biomass cooking.

    The study has revealed that only cow dung is not enough to produce clean energy according to demand so theco-digestion method is considered to producing biogas from various energy potentials (animal manure &agricultural waste). The poly-generation system could work with the scenario providing electricity and watersupply for the entire household and cooking gas is limited only for 2/3rd household. Rest 1/3rd household fromlow income group then could be supplied with improve cook stove to meet their daily cooking demand and tominimize indoor pollutions. It is observed that, majority of household has expressed their willingness toprovide raw materials for poly-generation plant though they are using.

    Fulltekst (pdf)
    fulltext
567891011 351 - 400 of 18397
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf