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  • 1.
    Abbas, Wasim
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Asghar, Imran
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    The Role of Leadership In Organizatinal Change: Relating the successful Organizational Change with Visionary and Innovative Leadership2010Independent thesis Advanced level (degree of Master (One Year)), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    The globalization has converted the world into a small global village; a village in which there is an ever high stream of contentions and competitions between organizations. In this scenario the most effective and beneficial maneuver for any organization is to create innovative ways in conducting business. This thesis deals with the role of leadership in the phenomena of organizational change and innovation. The leader as a person in charge or as a change agent can manage an organization or the process of organizational change more effectively and successfully if h/she is capable and competent. Rapid technological advancements, high expectations of customers, and ever changing market situations have compelled organizations to incessantly reassess and reevaluate how they work and to understand, adopt and implement changes in their business model in response of changing trends. Organizational change is a demand of the day, and needed for organizations to survive. Organizations now a days, well understand the importance of the matter, and are serious to prepare themselves not only the current, but also for the future trends to get the level of sustainable success, but Along with all of its implications and importance the process of organizational change is also a very complex and challenging.  Research shows that 70 percent of organizational changes fail to get their goals. As leadership has a central role in evolution and cultivating an organization, the process of organizational change demands a very effective and highly competent leadership that is well capable to perceive the most desirable shape of an organization and address the issue of organizational change in most appropriate way. The analysis of literature reviewed and the results of real life cases of organizations which are studied for this thesis shows, that a leadership with the competencies of “Vision” and “Innovative Approach” along with other characteristics can prove more effective to conclude the complex phenomena of organizational change with success. Further the successful organizational change can leads to innovation for organization, which is the key of long term success and sustainability. This thesis as a result proposed a model which is derived from the leadership competencies, organizational change, and sustainable success and innovation literature. This model expresses relationship between successful organizational change and leadership on the basis of h/her characteristics, which are ‘Vision” and “Innovative Approach”. With the help of proposed model this relationship can be viewed graphically.

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  • 2.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Airborne wear particles from train traffic2010Conference paper (Refereed)
  • 3.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olander, Lars
    A field investigation of the size and morphology and chemical composition of airborne particles in rail transport2010Conference paper (Refereed)
  • 4.
    Abdalameir, Hussein
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Daher, Maher
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Standardization of interfaces for electrical cabinets: How to optimize time saving and cost efficiency for electrical cabinets in submarines2022Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Background: In general, it is very complicated to build submarines. There are many parts and equipment that must be in place, and there are tight spaces on the boat. As submarine development progresses and new modern concepts take shape, the installation of new equipment on board becomes more complex, placing higher demands on well-defined interfaces, both geometrically and logically. The approach to electrical cabinets today is to run the cables from the bottom or top through a cable transit system, and only after the cabinet is installed on the submarine can the cables be installed in the proper terminals. This means that the installation takes a lot of time and combined with the fact that there are so many cables sticking out of the cable grommet, the work becomes even more superficial as installers are also constrained by the tight space. Sometimes workers also must move around to make room for others to pass through other parts of the submarine. This means that workers must leave their jobs and move before resuming their work. The following can happen several times a day, which means more time is needed to install electrical cabinets on the submarine.

     

    Purpose: The purpose of this work is to develop and design a solution that is a standardized interface for equipment in the form of electrical cabinets that are present and used in submarines. In this way, the solution must be able to satisfy the different interfaces of the devices that the different subcontractors provide to the company. The created proposals must be illustrated with a CAD software to visualize the concept.

     

    Methodology: The research methodology used in this project is a combination of Participatory Action Research (PAR) and Design Thinking (DT).

     

    Result: The result presents a solution (ISO-box) that shows that it is possible to reduce and optimize the time to install the cabinet once the cabinet is permanently mounted on the submarine. The solution is presented in the form of a CAD model. The model is set up so that all the cables coming from the cable transit system have an adapter at the end, which has a counterpart in a box to the cabinet that is installed on the submarine. Then when the cabinet is assembled, all that must be done is to plug the right connector into the right place in this box. The box has colors for the connectors and numbering that makes it easier for the installer to know which adapter to use.

     

    Conclusions: The work shows that it is quite possible to change the current solution so that less time is needed in the final assembly of the cabinets. It will be easier to just connect the contacts and then leave room for others to pass in the confined spaces. It will also be easier to maintain, as the installer can replace broken contacts as the solution is modular, and there is the possibility of installing new equipment with ISO-box if necessary.

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  • 5.
    Abdallah, Lana
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Industrial Economics.
    Persson, Mattias
    Blekinge Institute of Technology, Faculty of Engineering, Department of Industrial Economics.
    The effects of environmental uncertainty conditions on organisational innovativeness and performance of SMEs.2014Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    Innovativeness is considered to be an important factor for firm’s survival and their ability to compete in today’s market. Therefore, researchers have become more interested in studying innovativeness and its drivers. Studies have also showed that there’s a positive relationship between environmental uncertainty and innovativeness. Organisations are responsive to turbulent environments through innovativeness in order to stay competitive and improve performance. The purpose of this thesis is to rank critical environmental factor’s effect on organisational innovativeness of small and medium enterprises in Sweden, through investigating the impact of market/demand turbulence and technological turbulence on innovativeness. Additionally, we want to examine the relationship between innovativeness and business performance, as well as the indirect relationship between environmental uncertainty and performance. Based on previous literature, we have developed hypotheses and proposed a research model to study the formulated problems. Data for the study were collected from 50 SMEs in Sweden, through a survey with well-known scales and were analysed using regression analysis. The results of the study, reveal that environmental uncertainty has a positive effect on the innovativeness of SMEs. In addition, technological turbulence showed to have a positive significant effect on an SME’s innovativeness; however, contrary to general belief, market/demand turbulence did not have any prominent effect. Our findings also proved that innovativeness have a strong positive impact on business performance, and that only technological turbulence have an indirect influence on performance through innovativeness. This study aimed to contribute to the management a better understanding, of which conditions of environmental turbulences SMEs should adapt to, in order to increase their level of innovativeness. Keywords: environmental uncertainty, organizational innovativeness, performance, market/demand turbulence, technological turbulence, SMEs.

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  • 6.
    Abdi, Adna Adam
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Demirovic, Adis
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    A concept development of the HirePadlock product.: With a focus on setting requirements for the product and implementing a customer survey2022Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Many industrial companies place high demands on product development, from a simple idea to a finished product and then bring it to market. Therefore, there has been a rapid development of methods, models and working methodes in product development. This development is mostley about the product having a balance between price, quality, customer adaptation, safety, production and less environmental impact. 

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  • 7.
    Abebe, Abay Damte
    et al.
    Halmstad University, School of Business, Engineering and Science.
    He, Qikang
    Halmstad University, School of Business, Engineering and Science.
    Foam Behavior Analysis Based On A Force Measurement System2018Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract

    In the world where every sector of industrial manufacturing is being converted toautomated systems, surface finishing processes like sanding and polishing seem to lag.This phenomenon is not surprising as these processes are complex to optimize. Therehave been projects going on with the support of European Commission to findsolutions under SYMPLEXITY (Symbiotic Human-Robot Solutions for ComplexSurface Finishing Operations). One of the projects in under this include poliMATIC(Automated Polishing for the European Tooling Industry). Halmstad University isinvolved in doing projects.

    This project took a portion of this study in aim to understand a foam material’s behavior used for sanding tool at the tip of a robotic arm. This is studied using a forcemeasurement system developed at Halmstad University. The project has two sectionsand starts with one; Understanding the force measurement system and upgrading innecessary ways. Two; studying how the foam material compressive hardness propertyis affected when the material is fit with sandpaper for sanding operation using theforce measurement system. The study finally revealed how the combination of thefoam with sandpaper affects the robustness of the material, and significantlyimproved the output of the system with by reducing the noise level with 40%.

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  • 8.
    Abid, Muhammad
    KTH, Skolan för industriell teknik och management (ITM), Industriell ekonomi och organisation.
    Relationship between competitive priorities and global supply chain design: A conceptual frameworkManuscript (preprint) (Other academic)
  • 9.
    Abid, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.). Högskolan i Gävle, Sweden.
    Relationship between competitive priorities and global supply chain design: A conceptual frameworkManuscript (preprint) (Other academic)
  • 10.
    Abid, Muhammad
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.). Högskolan i Gävle, Sweden.
    Bengtsson, Lars
    Hellberg, Roland
    Dabhilkar, Mandar
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    Factors affecting global supply chain design2012Conference paper (Refereed)
    Abstract [en]

    Due to the limited existing knowledge pertaining to the factors which govern localization of operations and capabilities in a global supply chain, the purpose of the paper is to find out which factors and how they jointly affect the design of global supply chains. The relevant literature is reviewed and a concept matrix is developed. Five companies were selected in order to illustrate the issues of global supply chain design. Among them, three companies are considered to have efficient supply chain and less complex products, while the two others are considered to have responsive supply chain and more complex products. The issues discussed with the selected companies cover global sourcing, challenges, technological advancement and issues related to management control. The study identifies about fifty factors that affect global supply chain design, and specifically how theses relate to design decisions on location of factories and production, supplier selection and development, distribution of products and organisation of interfaces along the supply chain. The discrepancies between theory and practice as well as the implications for further research are discussed.

  • 11.
    Abidakun, Olatunde
    et al.
    Department of Mechanical and Aerospace Engineering, West Virginia University Morgantown, West Virginia, 26506, USA.
    Adebiyi, Abdulafeez
    Department of Mechanical and Aerospace Engineering, West Virginia University Morgantown, West Virginia, 26506, USA.
    Valiev, Damir
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Center for Combustion Energy, Key Laboratory for Thermal Science and Power Engineering of the Ministry of Education of China, Department of Energy and Power Engineering, Tsinghua University, Beijing, China.
    Akkerman, V’yacheslav
    Department of Mechanical and Aerospace Engineering, West Virginia University Morgantown, West Virginia, USA.
    Impacts of fuel nonequidiffusivity on premixed flame propagation in channels with open ends2021In: Physics of fluids, ISSN 1070-6631, E-ISSN 1089-7666, Vol. 33, article id 013604Article in journal (Refereed)
    Abstract [en]

    The present study scrutinizes premixed flame dynamics in micro-channels, thereby shedding light on advanced miniature micro-combustion technologies. While equidiffusive burning (when the Lewis number Le = 1) is a conventional approach adopted in numerous theoretical studies, real premixed flames are typically non-equidiffusive (Le ≠ 1), which leads to intriguing effects, such as diffusional-thermal instability. An equidiffusive computational study [V. Akkerman et al., Combust. Flame 145, 675–687 (2006)] reported regular oscillations of premixed flames spreading in channels having nonslip walls and open extremes. Here, this investigation is extended to nonequidiffusive combustion in order to systematically study the impact of the Lewis number on the flame in this geometry. The analysis is performed by means of computational simulations of the reacting flow equations with fully-compressible hydrodynamics and onestep Arrhenius chemical kinetics in channels with adiabatic and isothermal walls. In the adiabatic channels, which are the main case of study, it is found that the flames oscillate at low Lewis numbers, with the oscillation frequency decreasing with Le, while for the Le > 1 flames, a tendency to steady flame propagation is observed. The oscillation parameters also depend on the thermal expansion ratio and the channel width, although the impacts are rather quantitative than qualitative. The analysis is subsequently extended to the isothermal channels. It is shown that the role of heat losses to the walls is important and may potentially dominate over that of the Lewis number. At the same time, the impact of Le on burning in the isothermal channels is qualitatively weaker than that in the adiabatic channels.

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  • 12.
    Abrahamsson, Mats
    et al.
    Linköping University, Department of Management and Engineering, Logistics Management. Linköping University, The Institute of Technology.
    Rehme, Jakob
    Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics. Linköping University, The Institute of Technology.
    The Role of Logistics in Retailers' Corporate Strategy: A Driver for Growth and Customer Value2010In: Supply Chain Forum: an International Journal, ISSN 1625-8312, E-ISSN 1624-6039, Vol. 11, no 4, p. 14-23Article in journal (Refereed)
    Abstract [en]

    This article explores the role of logistics and supply chain management (SCM) in retailers’ corporate strategy and is based on reviewing multiple qualitative case studies of companies in the Swedish food retail sector. The article proposes that the role of logistics for what is referred to in this paper as modern retailers is twofold: to create profitability and to support growth and market expansion. International modern retailers are empirically compared with similar companies in the Swedish market. The dominating Swedish food retailers have taken command in the food supply chain but are primarily concerned with traditional logistics roles in cost cutting. This role is perfectly fine as long as the strategic intent of the companies is focused on market retention and not on geographical expansion and/or new marketing or store concepts. We argue that the success of modern retailers in terms of growth rate, profitability, and market expansion is explained to a large extent by the role of logistics in corporate strategy—when the role for supporting growth and increasing customer value from high-performance supply capabilities is a driver for market expansion. However, in many of our cases the traditional logistics roles of cutting costs and lead-times is still the dominating pattern that limits the possibility of expanding into new markets. Better knowledge of logistics’ role in retail corporate strategy can help companies develop and improve their strategic intent as well as redefine the role of logistics.

  • 13.
    Abu Baker Karim, Aria
    et al.
    Örebro University, School of Science and Technology.
    Schnelzer, Anna
    Örebro University, School of Science and Technology.
    Optimering av glidlager och utveckling av dess konstruktion2012Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    We have in this project become engrossed in a plain bearing design that is located in a screw press. The screw press compact an unknown mass that is confidential. Robustus have a suggestion to over dimensioning the present plain bearing. The aim of this project was to analyze and to do an optimization on some plain bearings and compare them to the present bearing and to take the choice of material and the environment where the bearing is located into account. The analysis and the optimizations showed that the current plain bearing had the best geometry but not the optimal material selection. The project is in an early state and it needs some geometrical changes. The most important of everything is that the problem has been identified with the help of the wrecked plain bearing and with an excel model.

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  • 14.
    Abu Sa'a, Ehab
    et al.
    Linköping University, Department of Management and Engineering, Project Innovations and Entrepreneurship. Linköping University, Faculty of Science & Engineering.
    Elg, Mattias
    Linköping University, Department of Management and Engineering, Logistics & Quality Management. Linköping University, Faculty of Science & Engineering.
    Yström, Anna
    Linköping University, Department of Management and Engineering, Project Innovations and Entrepreneurship. Linköping University, Faculty of Science & Engineering.
    Guests or Collaborators? Exploring Industrial Engagement in University-Industry Collaborations2024Conference paper (Refereed)
  • 15.
    Achten, Peter A J
    et al.
    Innas BV, Breda, Netherlands.
    Vael, Georges E M
    Innas BV, Breda, Netherlands.
    Heybroek, Kim
    Volvo Construction Equipment, Eskilstuna, Sweden.
    Efficient hydraulic pumps, motors and transformers for hydraulic hybrid systems in mobile machinery2011In: VDI-Fachkonferenz Getriebe in Mobilen Arbeitsmaschinen, Düsseldorf: VDI-Wissensforum , 2011, p. 1-19Conference paper (Refereed)
    Abstract [en]

    A detailed simulation of a large 33 metric ton wheel loader, carrying out the short loading cycle, has been performed. Two systems have been compared and examined side by side:

    • The conventional system, having a mechanical transmission for driving the wheels and a conventional load sensing hydraulic circuit for the work and steering cylinders.
    • A new hydraulic hybrid system for the wheel drive and the implements, applying new and efficient hydrau- lic pumps and motors.The core of the new system is the hydraulic transformers which convert and control all the hydraulic power flows inside the loader.

    The new system results in a reduction of the fuel consumption of about 50% in the analyzed cycle. The new transmission and hydraulic system also results in a strong reduction of the cooler demands.

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    Efficient hydraulic pumps, motors and transformers for hydraulic hybrid systems in mobile machinery
  • 16.
    Aco, Dekan
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Tillverkningsekonomisk utvärdering av återvinning och återanvändning av blyfri mässing2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master thesis is part of a larger project (Evochip), conducted at Lund University, faculty of engineering, Industrial Production Department (iProd). The project is in collaboration with AB Markaryds metallarmatur and Mistra innovation. In this work, a dynamic cost model has been developed to calculate the manufacturing costs of components made from recycled chips of lead-free brass from the manufacturing processes of AB Markaryds metallarmatur (MMA).

    In the current situation, all rejected details and waste materials are sent to the material supplier in southern Europe for recycling. The transport takes place by trucks and the recycling process is based on an energy-intensive melting step. Development projects are currently underway to reuse the chips without melting at sight at MMA´s facilities, but the cost per detail has been unknown for the company. With the help of this thesis, the manufacturing price will be presented. The manufacturing process is divided into a total of 11 different processing stations. To estimate the costs, Jan-Eric Ståhl's dynamic cost model is used. Necessary data and information have been collected using interviews with the employees of the company and through the company's own documentation regarding the production lines. In order to reduce the error margin in the results, suitable Monte Carlo simulations have been performed.

    The work is also based on a sustainability perspective. In addition to eliminating transportations by trucks and energy-intensive melting processes for the products, the work also promotes the use and reuse of lead-free brass by pressing metal chips to form new bars. All this in order to avoid leaded brass components due to the negative health effects caused by the lead.

    The component investigated in this work is a radiator valve called EVO 10. The valve is found in the company's lead-free standard range. The cost model in this project is dynamic to the extent that it could be applied in the future to other lead-free brass components at MMA.

    A comparison of two different concepts is presented in the results section. Concept one represents the current manufacturing system, and concept two, the future compacting technology. Since many of the processing steps are the same for both systems, a comparison was made between the productions of the pellet through the two different concepts. The results show that pellets made according to today's manufacturing system cost 12.75 SEK / detail, and pellets manufactured according to concept two costs 9.61 SEK / detail.

    As concept two is dependent on chips from today's manufacturing system, MMA cannot completely switch to compacting chips to new pellets. More work must be done to find a balanced model between the two different manufacturing systems for the best possible results.The results from the Monte Carlo-simulations shows that the manufacturing cost with the chosen parameters and variables is 12.96 SEK/detail.

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  • 17.
    Adamson, Göran
    et al.
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Wang, Lihui
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre. Department of Production Engineering, Royal Institute of Technology, Stockholm, Sweden.
    Moore, Philip
    University of Skövde, School of Engineering Science. University of Skövde, The Virtual Systems Research Centre.
    Feature-based control and information framework for adaptive and distributed manufacturing in cyber physical systems2017In: Journal of manufacturing systems, ISSN 0278-6125, E-ISSN 1878-6642, Vol. 43, p. 305-315Article in journal (Refereed)
    Abstract [en]

    Modern distributed manufacturing within Industry 4.0, supported by Cyber Physical Systems (CPSs), offers many promising capabilities regarding effective and flexible manufacturing, but there remain many challenges which may hinder its exploitation fully. One major issue is how to automatically control manufacturing equipment, e.g. industrial robots and CNC-machines, in an adaptive and effective manner. For collaborative sharing and use of distributed and networked manufacturing resources, a coherent, standardised approach for systemised planning and control at different manufacturing system levels and locations is a paramount prerequisite.

    In this paper, the concept of feature-based manufacturing for adaptive equipment control and resource-task matching in distributed and collaborative CPS manufacturing environments is presented. The concept has a product perspective and builds on the combination of product manufacturing features and event-driven Function Blocks (FB) of the IEC 61499 standard. Distributed control is realised through the use of networked and smart FB decision modules, enabling the performance of collaborative run-time manufacturing activities according to actual manufacturing conditions. A feature-based information framework supporting the matching of manufacturing resources and tasks, as well as the feature-FB control concept, and a demonstration with a cyber-physical robot application, are presented.

  • 18.
    Adebiyi, Abdulafeez
    et al.
    Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, West Virginia 26506, USA.
    Alkandari, Rawan
    Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, West Virginia 26506, USA.
    Valiev, Damir
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Center for Combustion Energy, Key Laboratory for Thermal Science and Power Engineering of the Ministry of Education of China, Department of Energy and Power Engineering, Tsinghua University, Beijing, China.
    Akkerman, V’yacheslav
    Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, West Virginia, USA.
    Effect of surface friction on ultrafast flame acceleration in obstructed cylindrical pipes2019In: AIP Advances, E-ISSN 2158-3226, Vol. 9, no 3, article id 035249Article in journal (Refereed)
    Abstract [en]

    The Bychkov model of ultrafast flame acceleration in obstructed tubes [Valiev et al., "Flame Acceleration in Channels with Obstacles in the Deflagration-to-Detonation Transition," Combust. Flame 157, 1012 (2010)] employed a number of simplifying assumptions, including those of free-slip and adiabatic surfaces of the obstacles and of the tube wall. In the present work, the influence of free-slip/non-slip surface conditions on the flame dynamics in a cylindrical tube of radius R, involving an array of parallel, tightly-spaced obstacles of size αR, is scrutinized by means of the computational simulations of the axisymmetric fully-compressible gasdynamics and combustion equations with an Arrhenius chemical kinetics. Specifically, non-slip and free-slip surfaces are compared for the blockage ratio, α, and the spacing between the obstacles, ΔZ, in the ranges 1/3 ≤ α ≤ 2/3 and 0.25 ≤ ΔZ/R ≤ 2.0, respectively. 

    For these parameters, an impact of surface friction on flameacceleration is shown to be minor, only 1-4%, slightly facilitating acceleration in a tube with ΔZ/R = 0.5 and moderating acceleration in thecase of ΔZ/R = 0.25. Given the fact that the physical boundary conditions are non-slip as far as the continuum assumption is valid, the presentwork thereby justifies the Bychkov model, employing the free-slip conditions, and makes its wider applicable to the practical reality. Whilethis result can be anticipated and explained by a fact that flame propagation is mainly driven by its spreading in the unobstructed portion ofan obstructed tube (i.e. far from the tube wall), the situation is, however, qualitatively different from that in the unobstructed tubes, wheresurface friction modifies the flame dynamics conceptually.

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  • 19.
    Adebiyi, Abdulafeez
    et al.
    Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, WV 26506-6106, United States.
    Idowu, Gbolahan
    Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, WV 26506-6106, United States.
    Valiev, Damir
    Center for Combustion Energy, Tsinghua University, Beijing 100084, China.
    Akkerman, V'yacheslav
    Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, WV 26506-6106, United States.
    Computational simulations of nonequidiffusive premixed flames in obstructed pipes2018Conference paper (Refereed)
    Abstract [en]

    The impact of the Lewis number, Le, on the dynamics and morphology of a premixed flame front, spreading through a toothbrush-like array of obstacles in a semi-open channel, is studied by means of the computational simulations of the reacting flow equations with fully-compressible hydrodynamics and Arrhenius chemical kinetics. The computational approach employs a cell-centered, finite-volume numerical scheme, which is of the 2nd-order accuracy in time, 4th-order in space for the convective terms, and of the 2nd-order in space for the diffusive terms. The channels of blockage ratios 0.33∼0.67 are considered, with the Lewis numbers in the range 0.2≤Le≤2.0 employed. It is shown that the Lewis number influences the flame evolution substantially. Specifically, flame acceleration weakens for Le>1 (inherent to fuel-lean hydrogen or fuel-rich hydrocarbon burning), presumably, due to a thickening of the flame front. In contrast, Le<1 flames (such as that of rich hydrogen or lean hydrocarbon) acquire an extra strong folding of the front and thereby accelerate even much faster. The later effect can be devoted to the onset of the diffusional-Thermal combustion instability. © 2018 Eastern States Section of the Combustion Institute. All rights reserved.

  • 20.
    Adebring, Carl Jonas
    et al.
    Linköping University, Department of Management and Engineering.
    Zachrisson, Fredrik
    Linköping University, Department of Management and Engineering.
    Leverantörsrelationer på Volvo Aero Corporation: En modell för val av lämplig strategi för leverantörshantering2007Independent thesis Basic level (professional degree), 20 points / 30 hpStudent thesis
    Abstract [en]

    Volvo Aero Corporation is one of the major subcontractors for the three big aero-engine manufacturers today, Rolls-Royce, General Electric and Pratt & Whitney. The company produces parts that are in over 80 % of commercial jet engines today. New engine programs where Volvo Aero tries to have a more active part in the design and development of the engine as well as consolidation among its suppliers has resulted in new challenges for the company. To fulfill these new demands there is an interest in improving the company’s relationships and collaboration with its suppliers to improve efficiency, costs and lead-times for these projects.

    To achieve this, Volvo Aero gave us the task to study and analyze theories on the subject of supplier relationships to determine if there was anything substantial that could be applied to the new situations that the company faces.

    We based our studies on a wide range of theories with the objective of finding parameters that were applicable to Volvo Aero as well as having a definite impact on the supplier relationship. A lot of the theory that we found was based on the automotive industry and lean production, and from this we tried to narrow the theories we studied down to their most basic parameters. The parameters we searched for were those that reflected the specifics that make up a relation between two companies, for example the power balance in the relationship or the amount of adaptation and investment in the relation.

    From there we built a model where we applied and adapted our parameters to the specifics of Volvo Aero. The model we created is used to deduce what kind of relationship is appropriate given the reality that our parameters should have captured should have captured the basis for a relationship.

    We then applied this model to analyze three specific cases as well as a general analysis of the supplier relations of the company. The cases were supplier relations that Volvo Aero wanted us to study more in depth and on these we applied the model as usual. With the general analysis we were forced to do a more abstract reasoning where we based our analysis on the parameters and theories that made up the model.

    What we found from this analysis was that the model was working the way we intended and that it was possible to apply these theories to this company with good results. We also think that this model, with possibly small adjustments, should be applicable to a wide range of corporate relations as well as to other companies.

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  • 21. Adlerborn, J
    et al.
    Björk, L
    Westman, Anna-Karin
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Larker, H
    Particulate-reinforced ceramics densified by glass encapsulated HIP1991In: Hot isostatic pressing: Theory and applications / [ed] R J Schaefer; Melvin Linzer, Materials Park, Ohio: ASM International, 1991, p. 211-216Conference paper (Refereed)
  • 22.
    Adolfsson, Albin
    Jönköping University, School of Engineering, JTH, Product Development.
    Konstruktion av campingbord: Utvecklingsprocessen för ett campingbord i aluminium1994Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis
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    fulltext
  • 23.
    Adolfsson, Erika
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Automatiseringskonstruktion till mätfixtur2019Independent thesis Basic level (university diploma), 12 credits / 18 HE creditsStudent thesis
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    BTH2019Adolfsson
  • 24. Adrovic, Dzemil
    Utveckling av metoder att mäta centrering av skruvhål i skär2013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    There have been, in some rare cases, difficulties with clamping of inserts with U-holes

    in their tool holder. According to the complaints, the inserts could not be properly

    clamped or could fracture when clamped. A study has shown that variations in

    clamping behaviour are mainly depending by the position of the screw hole in the tool

    holder and the centering of the screw hole in the insert.

    The focus of this project has been the centering of screw hole in insert. It has been

    shown that the screw holes are not always enough centered in the insert. The

    problem may occur after a certain step in the production, i.e. peripheral grinding.

    Today, the centering can be measured by a certain measurement jig. The

    measurement jig has a very good Gauge R and R value but is not easy to use,

    especially if it is to be reinstated into the production. The aim of this thesis has been

    to use SmartScope for developing a new method for measuring the centering of

    screw hole in insert. The goal with the new method was to be able to measure faster

    and to be easier to use than the existing one.

    The project was started with exercises and exploration of some of the functions of

    SmartScope and its software Measuremind 3D. Parallel with this, a study was made of

    the existing documentation for a better understanding of the problem.

    A method which measures how well the screw holes are centered in their inserts has

    been developed. The method consists of a number of measuring tools which are

    joined into a measurement sequence. Measurements of single inserts are fully

    automated. Provided that a system which picks and puts the inserts in specific

    locations can be implemented, a series of inserts can be measured fully automated.

    This method is faster and especially more automated than the current measurement

    jig. Measurements have shown that the accuracy of the method is well within the

    tolerance and that it has a good repeatability.

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    Dzemil Adrovic Examensarbete
  • 25.
    Aeeni, Soheila
    Linköping University, Department of Management and Engineering, Machine Design.
    Development of an Open-source Multi-objective Optimization Toolbox2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The industrial trend is currently to increase product customization, and at the same time decrease cost, manufacturing errors, and time to delivery. These are the main goal of the e-FACTORY project which is initiated at Linköping university to develop a digital framework that integrates digitization technologies to stay ahead of the competitors. e-FACTORY will help companies to obtain a more efficient and integrated product configuration and production planning process.

    This thesis is a part of the e-FACTORY project with Weland AB which main mission is the optimization of spiral staircase towards multiple disciplines such a scost and comfortability. Today this is done manually and the iteration times are usually long. Automating this process could save a lot of time and money.

    The thesis has two main goals, the first part is related to develop a generic multi-objective optimization toolbox which contains NSGA-II and it is able to solve different kinds of optimization problems and should be easy to use as much as possible. The MOO-toolbox is evaluated with different kinds of optimization problems and the results were compared with other toolboxes. The results seem confident and reliable for a generic toolbox. The second goal is to implement the optimization problem of the spiral staircase in the MOO-toolbox. The optimization results achieved in this thesis shows the benefits of optimization for this case and it can be extended by more variables to obtain impressive results.

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    fulltext
  • 26.
    Af Ugglas, Samuel
    et al.
    Scania CV AB, Scania CV AB.
    Vlasenko, Tayisiya
    Scania CV AB, Scania CV AB.
    Ersson, Anders
    Scania CV AB, Scania CV AB.
    Pettersson, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Process Technology.
    Kusar, Henrik
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Process Technology.
    Reactivity of Diesel Soot from 6- and 8-Cylinder Heavy-Duty Engines2023Conference paper (Refereed)
    Abstract [en]

    Increasing concern for air pollution together with the introduction of new types of fuels pose new challenges to the exhaust aftertreatment system for heavy-duty (HD) vehicles. For diesel-powered engines, emissions of particulate matter (PM) is one of the main drawbacks due to its effect on health. To mitigate the tailpipe emissions of PM, heavy-duty vehicles are since Euro V equipped with a diesel particulate filter (DPF). The accumulation of particles causes flow restriction resulting in fuel penalties and decreased vehicle performance. Understanding the properties of PM produced during engine operation is important for the development and optimized control of the DPF. This study has focused on assessing the reactivity of the PM by measuring the oxidation kinetics of the carbonaceous fraction. PM was sampled from two different heavy-duty engines during various test cycles. The heavy-duty engines were 6- and 8-cylinder direct injection diesel engines rated at 550 and 650 hp respectively. Reaction kinetics of the samples and characteristic oxidation temperatures were assessed by the non-isothermal thermogravimetric analysis (TGA) employing a multiple-ramp rates method in a 10% oxygen atmosphere. The oxidation of the diesel soot was compared with a model soot, Printex-U, and values were compared with the existing literature. The calculated activation energies range between 114.8 and 155.8 kJ/mol for diesel soot as well as the Printex-U samples indicating similar reactivity despite differences in engine configuration, fuel chemistry or, aging.

  • 27.
    Afshar, Reza
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics. Uppsala University.
    Cheylan, Matthieu
    École Nationale Supérieure de Mécanique et des Microtechniques, Besançon.
    Almkvist, Gunnar
    Department of Molecular Sciences, Swedish University of Agricultural Sciences.
    Ahlgren, Anders
    The Swedish National Maritime and Transport Museums, The Vasa Museum.
    Gamstedt, E. Kristofer
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Applied Mechanics. Uppsala University.
    Creep in oak material from the Vasa ship:: verification of linear viscoelasticity and identification of stress thresholds2020In: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736X, Vol. 78, no 6, p. 1095-1103Article in journal (Refereed)
    Abstract [en]

    Creep deformation is a general problem for large wooden structures, and in particular for shipwrecks in museums. In this study, experimental creep data on the wooden cubic samples from the Vasa ship have been analysed to confrm the linearity of the viscoelastic response in the directions where creep was detectable (T and R directions). Isochronous stress–strain curves were derived for relevant uniaxial compressive stresses within reasonable time spans. These curves and the associated creep compliance values justify that it is reasonable to assume a linear viscoelastic behaviour within the tested ranges, given the high degree of general variability. Furthermore, the creep curves were ftted with a one-dimensional standard linear solid model, and although the rheological parameters show a fair amount of scatter, they are candidates as input parameters in a numerical model to predict creep deformations. The isochronous stress–strain relationships were used to defne a creep threshold stress below which only negligible creep is expected. These thresholds ranges were 0.3–0.5 MPa in the R direction and 0.05–0.2 MPa in the T direction.

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    fulltext
  • 28.
    Aftab, Ahmad
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Mechatronics.
    Andersson, Kjell
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Khan, Suleman
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Mechatronics.
    A stiffness modeling methodology for simulation-driven design of haptic devices2014In: Engineering with Computers, ISSN 0177-0667, E-ISSN 1435-5663, Vol. 30, no 1, p. 125-141Article in journal (Refereed)
    Abstract [en]

    Efficient development and engineering of high performing interactive devices, such as haptic robots for surgical training benefits from model-based and simulation-driven design. The complexity of the design space and the multi-domain and multi-physics character of the behavior of such a product ask for a systematic methodology for creating and validating compact and computationally efficient simulation models to be used in the design process. Modeling the quasi-static stiffness is an important first step before optimizing the mechanical structure, engineering the control system, and performing hardware in the loop tests. The stiffness depends not only on the stiffness of the links, but also on the contact stiffness in each joint. A fine-granular Finite element method (FEM) model, which is the most straightforward approach, cannot, due to the model size and simulation complexity, efficiently be used to address such tasks. In this work, a new methodology for creating an analytical and compact model of the quasi-static stiffness of a haptic device is proposed, which considers the stiffness of actuation systems, flexible links and passive joints. For the modeling of passive joints, a hertzian contact model is introduced for both spherical and universal joints, and a simply supported beam model for universal joints. The validation process is presented as a systematic guideline to evaluate the stiffness parameters both using parametric FEM modeling and physical experiments. Preloading has been used to consider the clearances and possible assembling errors during manufacturing. A modified JP Merlet kinematic structure is used to exemplify the modeling and validation methodology.

  • 29.
    Aftab, Ahmad
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Mechatronics.
    Khan, Suleman
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Mechatronics.
    Andersson, Kjell
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Kinematics and Dynamics of a novel 6-DoF TAU Haptic Device2011In: Proceedings of the 2011 IEEE International Conference on MechatronicsInternational Conference on Mechatronics, April 13-15, 2011, Istanbul, Turkey, IEEE conference proceedings, 2011, p. 719-724Conference paper (Refereed)
    Abstract [en]

    This paper presents the kinematics and dynamics modeling of a novel hybrid kinematic concept, i.e. the TAU haptic device. This new concept was obtained from the modification of TAU-2 structure proposed by Khan et al. First a kinematic model for inverse and forward kinematics was developed and analyzed. Then an algorithm to solve the close form inverse dynamics is presented using Lagrangian formulation. Numerical simulation was carried out to examine the validity of the approach and accuracy of the technique employed. A trigonometric helical trajectory of 5th order spline was developed in Cartesian space for each degree of freedom of the moving platform in order to verify and simulate the inverse dynamics; the motion of the platform is such that the tool centre point remains on this trajectory while its orientation is changing constantly in roll, pitch and yaw.

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    fulltext
  • 30.
    Agenyi, Benjamin
    Blekinge Institute of Technology, Faculty of Engineering, Department of Industrial Economics.
    Mobile Banking and Entrepreneurship in Developing Countries:A case study of Nigeria2013Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    The purpose of this study was to identify ways by which entrepreneurial mobile banking growth could be accelerated in developing countries. An exploratory research method was adopted to identify the facilitators and obstacles to entrepreneurial mobile banking. The finding reveals some facilitators which include government policies and efforts of donor agencies, stiffer competition among banks, need for efficiency and lower cost, telecoms focus on customers retention. While some obstacles include conservative and vague regulation, security issues, underdeveloped infrastructures, lack of interoperability and lack of basic need for financial services. The main contribution of this study is the concise identification of the facilitators and obstacles to entrepreneurial mobile banking especially in developing countries. Suggestion for further study was made. The findings could be useful to policy-makers, donor agencies and other development partners in designing and directing their policies intervention

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    FULLTEXT01
  • 31.
    Aggerstam, Elina
    et al.
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Lehman, Karolina
    Linnaeus University, Faculty of Technology, Department of Mechanical Engineering.
    Materialvalets miljöpåverkan på transporten: En jämförelsestudie mellan transporter till flerfamiljshus i trä och betong.2017Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    Under året 2015 bedömde 240 av Sveriges 290 kommuner att det existerade ett underslott på bostäder. För att kunna möta behovet krävs det att många bostäder ska byggas på en kort tid. Med de klimathot som världen står inför krävs det att produktionen är uthållig och hållbar i längden. För att nå klimatmålen måste användandet av tunga fordon minskas, logistiken måste effektiviseras och alternativa transportmedel bör undersökas.

    Syftet med studien var att identifiera eventuella skillnader mellan byggnadsmaterialen trä och betong i transportledet. Med den insamalade datan togs olika relations- och nyckeltal fram som sedan utgjorde basen för de två formlerna som presenteras i studien.

    Resultatet av de olika relationstalen indikerar på att den lastade vikten inte har stor betydelse på hur mycket CO2 som släpps ut, utan att det är antalet transporter med tung lastbil som är grundproblemet till utsläppen och miljöpåverkan. Med formlerna som presenteras i studien kan antalet transporter som krävs till ett flerfamiljshus räknas ut, men även mängden CO2 som släpps ut vid fraktandet av planelementen.

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    Materialvalets miljöpåverkan på transporten
  • 32.
    Agnelli, Filippo
    et al.
    CNRS, École polytechnique, FRA.
    Nika, Grigor
    Weierstrass Institute for Applied Analysis and Stochastics, DEU.
    Constantinescu, Andrei
    CNRS, École polytechnique, FRA.
    Design of thin micro-architectured panels with extension–bending coupling effects using topology optimization2022In: Computer Methods in Applied Mechanics and Engineering, ISSN 0045-7825, E-ISSN 1879-2138, Vol. 391, article id 114496Article in journal (Refereed)
    Abstract [en]

    We design the micro-architecture of thin elastic panels to control their macroscopic behavior, accounting simultaneously for in-plane stiffness, out-of-plane stiffness and the extension–bending coupling effects. Our topology optimization method combines inverse homogenization, the Hadamard shape derivative and a level set method in the diffuse interface context to systematically capture within the unit cell the optimal micro-architecture. The efficiency of the solution method is illustrated through four numerical examples where the designed shape yields an important extension–bending coupling. The deformation responses under tensile loading are assessed numerically both on the complete periodic panel and on its homogenized twin plate. The results demonstrate that the simultaneous control of the in-plane, out-of-plane and their coupled behavior enables to shift a flat panel into a dome or a saddle shaped structure. Moreover, the obtained unit cells are elementary blocks to create directly 3D printable objects with shape-morphing capabilities.

  • 33.
    Agostini, Lara
    et al.
    University of Padova, Italy.
    Bengtsson, Lars
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Industrial economics. University of Gävle, Center for Logistics and Innovative Production.
    Lazzarotti, Valentina
    Carlo Cattaneo University LIUC, Italy.
    Manzini, Raffaella
    Carlo Cattaneo University LIUC, Italy.
    Nosella, Anna
    University of Padova, Italy.
    Pellegrini, Luisa
    Stefan, Ioana
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Industrial economics. University of Gävle, Center for Logistics and Innovative Production.
    Combining an external with an internal perspective on open innovation with scientific partners and patenting2017In: 18th International CINet Conference: Digitalization and innovation: designing the organization of the future, 2017Conference paper (Refereed)
  • 34.
    Agrawal, Tarun Kumar
    et al.
    University of Borås, Sweden.
    Pal, Rudrajeet
    he Swedish School of Textiles, University of Borås, S-50190 Borås, Sweden.
    Traceability in Textile and Clothing Supply Chains: Classifying Implementation Factors and Information Sets via Delphi Study2019In: Sustainability, E-ISSN 2071-1050, Vol. 11, no 06Article in journal (Refereed)
    Abstract [en]

    The purpose of this study is twofold. First, to explore and classify factors influencing traceability implementation, and second, to cluster essential traceability-related information that demands recording and sharing with businesses and customers, in the context of the textile and clothing supply chain. A Delphi study is conducted with 23 experts (including research practitioners and industry experts) to explore, validate, and classify traceability factors and related information using distribution analyses and hierarchal clustering. As a result, 14 factors and 19 information sets are identified and classified with a moderately high agreement among the experts. Among these, risk management, product authentication, and visibility are the highest ranked and the most important factors influencing traceability implementation in the textile and clothing supply chain. While origin, composition, and sustainability-related information are crucial for sharing with customers, the information vital to businesses includes manufacturer/supplier details, product specifications, and composition. It is noteworthy that this research is among the few that classifies traceability factors and information through expert perspectives, and it creates decisive knowledge of traceability for the textile and clothing supply chain. It further provides insights on the extent to which this information can be shared among supply chain actors. Outcomes of this study can be helpful for the development of an information traceability framework. Policymakers can use the results to draft traceability guidelines/regulations, whilst top management can develop traceability-related strategies.

  • 35.
    Ah Shenga, Pedro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    SAWING STRATEGIES FOR TROPICAL HARDWOOD SPECIES: Simulation studies based on industrial conditions of Mozambique2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The harvesting of Mozambique tropical hardwood species is considerable higher than the natural regrowth in the forest and the stock is decreasing drastically. Therefore, it is important to improve the material recovery when the wood is refined (i.e., in sawing and further refinement to products such as joineries, furniture etc.) to reduce the waste and to re-utilize efficiently the by-products to increase the added value. The wood processing industry is an important means to boost the industries in the rural areas and also to generate incomes for the local communities by creating jobs and business opportunities.

    The majority of the logging that can be used for sawmilling in Mozambique is exported as roundwood due to the inability of companies to meet the product standards set for export and to generate profit. The lack of capabilities of the local sawmills to generate profit, also foments the illegal logging because of the higher price of roundwood for export which contributes to increase the number of unlicensed individuals in harvesting. This threatens the law enforcement and thus the degradation of the local wood industry. An alternative to increase the profit and empower the local community could be to export more refined wood products such as sawn timber, parquet, and veneer instead of the roundwood.

    The objective of the work was to investigate alternative sawing strategies of tropical hardwood species that could increase the profitability of the Mozambique wood industry in general and at sawmill in particular. The subject was approached using a database of virtual logs and together with a sawing simulator. The thesis has two main focus areas: (1) creating the log database with the corresponding algorithms for sawing simulation, and (2) investigations of alternative sawing strategies.

    The first focus was to build the database of surface-scanned logs and develop the algorithm for the saw simulation. The results are a database of 15 logs models describing the logs outer shape in which 10 jambirre (Millettia stuhlmannii Taub.) and 5 umbila (Pterocarpus angolensis DC.), and the algorithm for the sawing simulation. The algorithm use “brute force” i.e., determines all volume yields of sawn timber from the combination of all settings of log-positioning parameters (offset, skew and rotation) and selects the maximum value of volume yield. From simulation, using three sawing patterns (cant-sawing, through-and-through sawing and square-sawing) combined with two positioning parameters (offset and rotation) it was found that the sawing pattern has great impact on volume yield and that the square-sawing gave higher yield followed by through-and-through sawing pattern.

    The second focus was on alternative sawing strategies; having in mind that the optimal volume yield is achieved by aid of computerized production systems and that these resources are not yet in use in Mozambique. Hence, the objective was to find the positioning parameters that can be set manually and improve the volume yield. The result have shown that the rotation is the most affecting parameter followed by offset and skew, and that the volume yield can decrease by between 7.7% and 12.5% from the optimal positioning when the logs are manually positioned with the knowledge about the optimal log position. In another study, using crook-up or horns-down positioning as alternative to the optimal positioning, the volume yield decreases by between 10% and 13% from the optimal positioning. By using bucked logs , the optimal volume yield increased by between 8% and 13% in relation to full lengths logs, and the volume yield of bucked logs when using crook up positioning decreases 2% in relation to optimal positioning of full length logs.

    It is concluded that there is an unexploited value potential in the wood chain which can be reached using alternative positioning and modern measurement techniques and that the grading of wood will facilitate and improve the sawing process.

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  • 36.
    Ah Shenga, Pedro António
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Bomark, Peter
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Broman, Olof
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    External Log Scanning for Optimizing Primary Breakdown of Tropical Hardwood Species2015Conference paper (Other academic)
    Abstract [en]

    The sawing of tropical hardwood species is a big challenge for sawmills in developing countries. In order to investigate sawing strategies and volume recovery of tropical hardwood species, a log shape database was created using a portable 3D laser scanner. The data were collected in Mozambique, where twelve Jambirre (Millettia stuhlmannii Taub.) and five Umbila (Pterocarpus angolensis DC) logs were scanned. The logs were selected among the most commercialized species and the crook was the main selection parameter. In addition, straight logs were incorporated as reference. A saw simulation Matlab algorithm that combines skew and rotation was developed. The results show that point cloud data from the 3D scanner provide detailed models of the external log geometry and accurately describe the log shapes and volumes. Preliminary results from breakdown simulation revealed that the through-and-through sawing pattern yields more than the cant saw pattern and that the increase in yield was almost the same for both species.

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    fulltext
  • 37.
    Ah Shenga, Pedro António
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Bomark, Peter
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Broman, Olof
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Simulated Breakdown of Two Tropical Hardwood Species2015In: Pro Ligno, ISSN 1841-4737, E-ISSN 2069-7430, Vol. 11, no 4, p. 450-456Article in journal (Refereed)
    Abstract [en]

    A simulation study has been performed on a small log database of tropical hardwoods consisting of 10 Jambirre (Millettia stuhlmannii Taub.) and 5 Umbila (Pterocarpus angolensis D.C.) logs. The outer log shape was acquired by a 3D laser scanner before sawing and the heartwood content was estimated by measurement on images of the centre slabs after through-and-through sawing. Yield and value recovery using different sawing techniques and different sawing patterns, together with rotational and skew positioning errors, are presented. The results show that through-and-through sawing in the best rotation and skew positions tested improves the yield of Umbila logs by an average of 4.5 percentage points and Jambirre logs by 3.6 percentage points compared to cant sawing. It can be concluded that positioning and sawing patterns have a great influence on the yield and value recovery of these species and that log grade and species have an impact on the sawing pattern that should be used.

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    fulltext
  • 38.
    Ah Shenga, Pedro
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Bomark, Peter
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Broman, Olof
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Hagman, Olle
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    3D Phase-shift Laser Scanning of Log Shape2014In: BioResources, E-ISSN 1930-2126, Vol. 9, no 4, p. 7593-7605Article in journal (Refereed)
    Abstract [en]

    In this paper, a portable scanner to determine the 3D shape of logs was evaluated and compared with the measurement result of a computer tomography scanner. Focus was on the accuracy of the shape geometry representation. The objective is to find a feasible method to use for future data collection in Mozambique in order to build up a database of logs of tropical species for sawing simulations. The method chosen here was a 3D phase-shift laser scanner. Two logs, a birch log with bark and a Scots pine log without bark, were scanned, resulting in 450 cross sectional “images” of the pine log and 300 of the birch log. The areas of each point cloud cross section were calculated and compared to that of the corresponding computer tomography cross section. The average area difference between the two methods was 2.23% and 3.73%, with standard deviations of 1.54 and 0.91, for the Scots pine and birch logs, respectively. The differences in results between the two logs are discussed and had mainly to do with presence of bark and mantle surface evenness. Results show that the shape measurements derived from these methods were well correlated, which indicates the applicability of a 3D phase-shift laser scanning technology for gathering log data.

  • 39.
    Ah Shenga, Pedro
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Bomark, Peter
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Broman, Olof
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Sandberg, Dick
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Log sawing positioning optimization and log bucking of tropical hardwood species to increase the volume yield2017In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 12, no 4, p. 257-262Article in journal (Refereed)
    Abstract [en]

    The sawmill industry is a very important link in the Mozambique forest products value chain, but the industry is characterized by undeveloped processing technology and high-volume export of almost unrefined logs. The low volume yield of sawn timber has been identified as a critical gap in the technological development of the industry. To improve the profitability of the industry, there is thus a need to develop methods and techniques that improve the yield. In this paper, different positioning of logs prior to sawing and the possibility of increasing the volume yield of crooked logs by bucking the logs before sawing have been studied. A computer simulation was used to study the cant-sawing and through-and-through sawing of the logs to determine the volume yield of sawn timber from the jambirre (Millettia stuhlmannii Taub.) and umbila (Pterocarpus angolensis DC.) species. The optimal position, i.e. the position of the log before sawing that gives the highest volume yield of sawn timber for a given sawing pattern when the positioning parameters, offset, skew and rotation, are considered gave a considerable higher volume yield than the horns-down position. By bucking very crooked logs and using the horns-down positioning before sawing, the volume yield can be of the same magnitude as that obtained by optimal positioning on full-length (un-bucked) logs. The bucking reduces the crook of the logs and hence increases the volume yield of sawn timber.

  • 40.
    Ah Shenga, Pedro
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Bomark, Peter
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Broman, Olof
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Sandberg, Dick
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Simulation of Tropical Hardwood Processing – Sawing Methods, Log Positioning, and Outer Shape2015In: BioResources, E-ISSN 1930-2126, Vol. 10, no 4, p. 7640-7652Article in journal (Refereed)
    Abstract [en]

    To increase understanding of breakdown strategies for Mozambican timber, simulations were carried out using different sawing patterns that can be alternatives to the low degree of refinement performed for export today. For the simulations, 3D models of 10 Jambirre and 5 Umbila logs were used. The log shape was described as a point cloud and was acquired by 3D-laser scanning of real logs. Three sawing patterns (cant-sawing, through-and-through sawing, and square-sawing) were studied in combination with the log positioning variables skew and rotation. The results showed that both positioning and choice of sawing pattern had a great influence on the volume yield. The results also showed that the log grade had an impact on the sawing pattern that should be used for a high volume yield. The volume yield could be increased by 3 percentage points by choosing alternative sawing patterns for fairly straight logs and by 6 percentage points for crooked logs, compared to the worst choice of sawing pattern.

  • 41.
    Ah Shenga, Pedro
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Bomark, Peter
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Broman, Olof
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Sandberg, Dick
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    The Effect of Log Position Accuracy on the Volume Yield in Sawmilling of Tropical Hardwood2016In: BioResources, E-ISSN 1930-2126, Vol. 11, no 4, p. 9560-9571Article in journal (Refereed)
    Abstract [en]

    This study investigated the effect of the positioning of the log before sawing on the volume yield of sawn timber from tropical hardwood species. Three positioning parameters were studied, the offset, skew, and rotation, combined with two sawing patterns of cant-sawing and through-and-through sawing. A database consisting of two tropical hardwood species with very different outer shapes, jambirre (Millettia stuhllmannii Taub.) and umbila (Pterocarpus angolensis DC.), was used to simulate the sawing process. The result of the simulation revealed that, according to the combined effect of offset, skew, and rotation positioning, the positioning of the log before sawing is extremely important to achieve a high volume yield of sawn timber. The positioning parameter that has the highest effect on the volume yield is the rotation, and the variation in the volume yield associated with a deviation in the positioning can reduce the volume yield of sawn timber by between 7.7% and 12.5%.

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  • 42.
    Ah Shenga, Pedro
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Cristovao, Luis
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Broman, Olof
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    A review of Mozambican wood exploitation: map of the processing chain2013In: Proceedings of the 21th International Wood Machining Semina: August 4th – 7th, Tsukuba International Congress Center, Japan, 2013, p. 293-301Conference paper (Other academic)
  • 43.
    Ahlm, Andreas
    et al.
    Jönköping University, School of Engineering, JTH, Industrial Engineering and Management.
    Salo, Erik
    Jönköping University, School of Engineering, JTH, Industrial Engineering and Management.
    Beslutsprocess för sourcingbeslut2006Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [en]

    It seems like outsourcing often does not live up to the expected results. Furthermore, sourcing decisions are often unplanned and improvised based upon insufficient short term foundation. Poor basis for sourcing decisions can lead to that some important factors, which can result in long term consequences, could get overlooked in the decision foundation.

    The purpose of the master thesis is to create a structured decision process that could lead to a well balanced sourcing decision and apply this at Husqvarna AB.

    The method used is a case study which includes a theoretical and an empirical study.

    The decision process is based upon the theoretical framework and is structured as a number of activities. Each activity includes a number of questions that should be answered if a well balanced sourcing decision is to be made. The questions are developed so that they include all the factors that could be affected by outsourcing.

    The case at Husqvarna AB was analyzed and evaluated by using the theoretical decision process. This showed how the decision process can be used by Husqvarna AB.

    The conclusion of the thesis is that the purpose was fulfilled since a decision process was developed that could be applied at Husqvarna AB.

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    FULLTEXT01
  • 44.
    Ahlqvist, Max
    Jönköping University, School of Engineering, JTH, Materials and Manufacturing.
    23 full factorial heat treatment experiment on Cu-Ni-Mo alloyed ADI: A literature study in HCF-VHCF properties of ADI and heat treatment experiments using a 23 full factorial design for potentially improved very high cycle fatigue strength2019Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Increasing knowledge and suggesting new heat treatment parameters for improved very high cycle fatigue (VHCF) strength of austempered ductile iron (ADI) are the main purposes of this thesis. The work was performed within Epiroc a mining and infrastructure company. They have performed internal research on VHCF properties of ADI had previously for one set of heat treatment parameters. The scientific community in contrast have extensively studied fatigue properties of ADI in the low to high cycle regime (≤108 cycles) but only scarcely in the VHCF regime (>108 cycles). Therefor the thesis is built upon the hypothesis: ‘Improvements in HCF strength should also mean improvements in VHCF strength’. Enabling utilization of published research on heat treatment effects on fatigue strength in the HCF regime (≥107 cycles).

    Finding an efficient way of exploring heat treatment parameters and their effects on the given Cu-Ni-Mo ADI alloy were a main objective. Thus, finding mechanical- and material properties characteristic for high cycle fatigue strength in the HCF regime became crucial. The potential in using these properties to develop and execute an experimental plan to evaluate heat treatments, yet minimizing the amount of fatigue testing required.

    The first step was identifying the heat treatment parameters (and parameter ranges) that showed high HCF strength, which are: Austempering temperature (Taus), austempering time (taus) and austenitization temperature (Tγ). Then finding the characteristic mechanical- and material properties for said high HCF strength material, found to be: high- ductility, unnotched impact energy and volume fraction of carbon stabilized austenite (VRA). With both heat treatment parameters, mechanical- and material properties distinctive of high HCF strength material an experimental plan was developed based on a full factorial design (23). The factorial design was chosen for its simplicity and inherent strengths, especially as both individual and interaction effects can be estimated for all factors (heat treatment parameters). Two levels (23), one high and one low, for each of the three factors (23) were determined necessary, giving a total of 8 heat treatment trials. The primary response variables of interest (evaluated properties) for each heat treatment trial were: ductility, unnotched impact energy and volume fraction of carbon stabilized austenite. Meaning usage of the following tests: Tensile testing, impact energy testing, and X-ray diffraction. Specimens for testing were extracted from austempered Y-block type III, initially cast by a commercial foundry with an Epiroc specified chemical composition. The main and interaction effects from the heat treatment parameters on the response variables were both calculated and visually determined. The experimental data was validated against literature found data for similar heat treatments. The evaluated experimental results showed good correlation with literature for the given chemical composition. Ultimately resulting in recommendations for a new heat treatment parameters for improved high cycle fatigue strength.

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  • 45.
    Ahlqvist, Nicolin
    et al.
    Mälardalen University, School of Innovation, Design and Engineering.
    Rydh, Mathilda
    Mälardalen University, School of Innovation, Design and Engineering.
    Valideringssystem för diskmaskin inom vården2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta arbete har tagit upp frågan om hur ett valideringssystem inom vården skulle kunna fungera på bästa sätt samt dess design

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  • 46.
    Ahlsén, David
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Naval Systems.
    Fartygsprojektering och Flytande havsbaserad vindkraft2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Den här rapporten behandlar tre områden anknutna till den gemensamma sektorn marina system. Inledningsvis beskrivs sjöfartsnäringens olika delar däribland olika typer av gods och fartygstyper samt sjöfartens aktörer och reglerande organ. Sjöfarten diskuteras med hänsyn till miljö och visar att godstransport till havs är relativt energieffektivt, men att alla typer av gods inte kan motiveras ur ett hållbart perspektiv.

    En inledande fartygsprojektering genomförs för ett transportscenario där 5500 ton kiwifrukt ska transporteras från Nya Zeeland till länder kring Östersjön inom en tidsrymd som garanterar att frukten håller god kvalitet. Fartygstypen är ett kylfartyg dimensionerat att rymma lasten, minimera motstånd och uppfylla stabilitetskriterier från IMO. För att uppfylla transportscenariot är fartyget designat för en marschfart på 20 knop, med ett deplacement på 12500 ton, en längd på 138 m, 21 m i bredd och ett djupgående på 7.7 m.

    Avslutningsvis identifieras kriterier och förutsättningar för flytande havsbaserad vindkraft. Detta med syfte genomföra en inledande projektering av en vindkraftpark stor nog att Gotland kan täcka sin elkonsumtion med endast förnybara energikällor. Parken anläggs längs en ny kabelanslutning mellan Gotland och fastlandet utom synhåll från såväl Gotland, Öland och fastlandet. Området uppfyller krav på vindförhållanden och utgörs av 24 vindkraftverk med kapacitet på 5 MW vardera.

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  • 47.
    Ahltoft, Anders
    et al.
    Jönköping University, School of Engineering, JTH, Industrial Product Development, Production and Design.
    Svensson, Dennis
    Jönköping University, School of Engineering, JTH, Industrial Product Development, Production and Design.
    Konceptstudie av formspråk av shuntautomatik2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    ESBE AB is a company with a long history that develops and sells plumbing and heating related products. Their products possess a markedly high quality and reliability along with a strong focus on their design language. The purpose of this thesis is to update this design language and produce three concepts that describes how it could be done. The thesis was carried out as a concept study, using a product development process to structure the work. The theories, methods and how those methods were carried out are also described. A large part of the study was dedicated to preliminary work which studied the history of the company, its brand strategy as well as the products position on the market in order to create a comprehensive basis for the concept generation phase and the concept selection phase. The study produced three final concepts that were presented to responsible parties at the company. All three concepts were considered to have potential for future implementation. ESBE intends to, after evaluation, eventually have one or several concepts be realized by a consulting firm that would produce prototypes and prepare for production. 

  • 48.
    Ahmad, Aftab
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Effective development of haptic devices using a model-based and simulation-driven design approach2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Virtual reality (VR)-based surgical simulators using haptic devices can increase the effectiveness of surgical training for surgeons when performing surgical procedures in hard tissues such as bones or teeth milling. The realism of virtual surgery through a surgical simulator depends largely on the precision and reliability of the haptic device, which reflects the interaction with the virtual model. The quality of perceptiveness (sensation, force/torque) depends on the design of the haptic device, which presents a complex design space due to its multi-criteria and conflicting character of functional and performance requirements. These requirements include high stiffness, large workspace, high manipulability, small inertia, low friction, high transparency, and cost constraints.

    This thesis proposes a design methodology to improve the realism of force/torque feedback from the VR-based surgical simulator while fulfilling end-user requirements.

    The main contributions of this thesis are:

    1. The development of a model-based and simulation-driven design methodology, where one starts from an abstract, top-level model that is extended via stepwise refinements and design space exploration into a detailed and integrated systems model that can be physically realized.

    2. A methodology for creating an analytical and compact model of the quasi-static stiffness of a haptic device, which considers the stiffness of actuation systems, flexible links and passive joints.

    3. A robust design optimization approach to find the optimal numerical values for a set of design parameters to maximize the kinematic, dynamic and kinetostatic performances of a 6-degrees of freedom (DOF) haptic device, while minimizing its sensitivity to variations in manufacturing tolerances and cost, and also satisfying the allowed variations in the performance indices.

    4. A cost-effective approach for force/torque feedback control using force/torque estimated through a recursive least squares estimation.

    5. A model-based control strategy to increase transparency and fidelity of force/torque feedback from the device by compensating for the natural dynamics of the device, friction in joints, gravity of platform, and elastic deformations.

     

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    Thesis
  • 49.
    Ahmad, Aftab
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Andersson, Kjell
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    A deterministic and probabilistic approach for robust optimal design of a 6-DOF haptic device2014In: Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference--2013: Volume 3 B, 2013, ASME Press, 2014, p. V03BT03A032-Conference paper (Refereed)
    Abstract [en]

    This work suggests a two-stage approach for robust optimal design of 6-DOF haptic devices based on a sequence of deterministic and probabilistic analyses with a multi-objective genetic algorithm and the Monte-Carlo method. The presented model-based design robust optimization approach consider simultaneously the kinematic, dynamic, and kinetostatic characteristics of the device in both a constant and a dexterous workspace in order to find a set of optimal design parameter values for structural configuration and dimensioning. Design evaluation is carried out based on local and global indices, like workspace volume, quasi-static torque requirements for the actuators, kinematic isotropy, dynamic isotropy, stiffness isotropy, and natural frequencies of the device. These indices were defined based on focused kinematic, dynamic, and stiffness models. A novel procedure to evaluate local indices at a singularity-free point in the dexterous workspace is presented. The deterministic optimization approach neglects the effects from variations of design variables, e.g. due to tolerances. A Monte-Carlo simulation was carried out to obtain the response variation of the design indices when independent design parameters are simultaneously regarded as uncertain variables. It has been observed that numerical evaluation of performance indices depends of the type of workspace used during optimization. To verify the effectiveness of the proposed procedure, the performance indices were evaluated and compared in constant orientation and in dexterous workspace.

  • 50.
    Ahmad, Aftab
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Andersson, Kjell
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    An approach to stiffness analysis methodology for haptic devices2011In: 2011 3rd International Congress on Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT), IEEE conference proceedings, 2011, , p. 8p. 1-8Conference paper (Refereed)
    Abstract [en]

    In this work a new methodology is proposed to model the static stiffness of a haptic device. This methodology can be used for other parallel, serial and hybrid manipulators. The stiffness model considers the stiffness of; actuation system; flexible links and passive joints. For the modeling of the passive joints a Hertzian contact model is introduced for both spherical and universal joints and a simply supported beam model for universal joints. For validation of the stiffness model a modified JP Merlet kinematic structure has been used as a test case. A parametric Ansys FEM model was developed for this test case and used to validate the resulting stiffness model. The findings in this paper can provide an additional index to use for multi-objective structural optimization to find an optimum compromise between a lightweight design and the stiffness performance for high precision motion within a larger workspace.

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