| 1331. |
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| 1332. |
- Sjödin, David Rönnberg
(författare)
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Managing joint development of process technologies : empirical studies of interorganizational collaboration within the process industries
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The concept of open innovation has gained widespread acceptance in different lines of research, and it has had a major impact on both research and practice during the last decade. The inherent logic of open innovation is simply that firms can and should use external as well as internal knowledge and information sources, and both internal and external paths to market, when they seek to maximize returns from development activities. While the mainstream literature has mainly reported on open innovation during product development, this thesis highlights the importance of open innovation activities during process development. Indeed, strong collaboration and significant joint development activities are typically required between buyers and suppliers when developing and implementing new process technologies. This is especially true in the process industries where process development is a key source of competitiveness. However, joint process development projects in this setting are often plagued by severe budget overruns, time delays, and quality problems. Developing and implementing new process technology is thus a risky endeavor that may seriously endanger long-term competitive advantages and the financial viability of firms if not managed proficiently. In particular, these projects are often complex to manage, as interdependencies among a number of actors, activities, and the overall process design create problems and information gaps for both buyers and suppliers. Therefore, there is a need for increased knowledge to facilitate improved collaboration so as to decrease the risk of project failure. Accordingly, the purpose of this thesis is to increase the understanding of how process firms and equipment suppliers can improve the management of joint development projects.Empirically, the results are based on three case studies and a comprehensive project-level survey within the process industries. The thesis is based on empirical data from 84 interviews with employees of two process firms and nine equipment suppliers as well as 251 survey respondents from 52 joint development projects. These numbers include respondents from eight European countries. The results can be summarized in a number of points. First, firms should revise their development processes to manage interorganizational collaboration. Second, different problems and collaborative activities must be managed as the project progresses from development to implementation. To this end, different stages require different participants and different modes of communication and coordination among participants. Thus, the content and the intensity of the collaboration should be tailored to the information processing needs in different stages of the equipment’s lifecycle. To support an appropriate collaboration process, firms should tailor their procurement procedures to the characteristics of the project. These findings present a number of implications for managers and practitioners alike in light of the increasing importance of interorganizational collaboration and process development.
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| 1333. |
- Sjögren, Anders
(författare)
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Matrix and interface effects on microcracking in polymer composites
- 1997
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- An underlying industrial problem for the present work is leakage of pressure vessels. Fluid leakage was confirmed to take place along a path of connected microcracks and delaminations. The thesis is concerned with the micromechanisms for microcracking studied by in-situ optical microscopy of cross-ply laminates. The strain at onset of transverse cracking and K, a measure of the slope of crack density versus strain, are important parameters. The role of matrix and interface is emphasized although new light is shed also on the role of micro- and mesolevel residual stresses. Damage initiation and development behavior of glass bead/polypropylene (PP) composites is studied. Thermoelastic finite element analysis demonstrates strong effects on interfacial debond strains from residual thermal strains although the high relaxation rate reduces the problem for PP. Interfacial debonding is also important in the glass fiber composite studies. Previous studies have shown the transverse fatigue behavior in tension-compression to be substantially worse than the behavior in transverse tension. This was demonstrated to be due to debond extension in compression caused by Mode I loading at the crack tip of large debonds. Single fiber composites of different interfacial strengths were also studied. The strong interface system did not fail in any single fiber test (fragmentation test, transverse tension, pullout) which points to a basic problem with these tests for systems with strong adhesion. As this fiber was used in cross-ply laminate tests, substantial improvement was observed in c., whereas K decreased. Similar effects were observed with increased matrix fracture toughness and decreased fiber content. This is because debonding is delayed as well as the subcritical crack growth prior to formation of a crack of critical size. Residual stresses were studied on thin transverse sections of unidirectional glass fiber/vinylester. In transmitted polarized light, distinct optical patterns were observed in densely packed chains of fibers close to isolated matrix regions. In finite element calculation results, the optical patterns associated with these critical mesoscale configurations correspond to regions with large compressive stresses. The finite element calculations were performed on a scanned microstructure image containing 1410 fibers. Despite the complexity and size of this microstructure and short fiber-fiber distances, calculation results were virtually exact for a thermoelastic 3D case. Residual stresses were sufficiently large to result in compressive yielding which may cause the optical effects. Experimental results indicate that glass fiber/vinylester with poor interfacial adhesion (possible in commercial materials, as demonstrated in the thesis) can suffer interfacial debonding due to residual stresses only. With glass fiber/polyester, even short cracks are formed due to microlevel residual stresses. In the near future, high precision stress-state calculations in combination with detailed experimental studies will allow us to solve mesoscale problems of great complexity. This will change some of the current paradigms. For instance, increased confidence in stress-state calculations will lead to the need for improved accuracy in measurements of the constitutive behavior of fibers, matrices and interfaces.
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| 1334. |
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| 1335. |
- Sjöholm, Jennie
(författare)
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Heritagisation, re-heritagisation and de-heritagisation of built environments : The urban transformation of Kiruna, Sweden
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This doctoral thesis presents research that aimed to contribute to the understanding of heritagisation in built environments and how heritagisation interacts with structural changes to an environment. The theoretical framework of the research was based on heritagisation, a concept defined by Harrison (2013) as the process through which objects, places and practices are turned into cultural heritage. The research was part of a single case study investigating conceptualisations of built heritage during the urban transformation of the town of Kiruna. Kiruna is a mining town in the northernmost part of Sweden that has plans to be relocated so that the mining company LKAB can continue mining the iron ore deposit that extends underneath the settlement. Kiruna is also a designated heritage site since the 1980s, and includes a large number of protected buildings. Hence, it is of interest how the built heritage is managed during the urban planning process. This is not only because the urban planning situation, which includes the relocation of an entire town, is special, but also because the town’s built heritage inevitably will change during the urban transformation. The research underlying this thesis has followed heritagisation during the urban transformation, from 2004, when the urban transformation was announced, until 2015. The empirical data used consist of planning documents, media reporting and observations, which together provide an overall view of the public discussions over the course of the urban planning process. Findings from the Kiruna case study show that the town’s officially recognised built heritage corresponds with the concept of an authorised heritage discourse (AHD). This heritage discourse was challenged by the urban transformation. Conservation goals are not clearly stated in the urban planning process and there are differing ideas for how to manage historic buildings during the urban transformation. These ideas shift both over time and between stakeholders, and the outcome of the urban planning process depends on a balance between the discourses of heritage conservation, urban development and architectural production. During the urban planning process some parts of the town’s official heritage have been reaffirmed as built heritage, while others have been dismissed. The concept of heritagisation was adopted and developed throughout the research presented in this thesis. This research also introduced the concepts of re-heritagisation and de-heritagisation, which refer to new heritagisation processes that occur when built heritage is contested and challenged during urban change. One of the main conclusions of the research was that the changes in meaning during the heritagisation process can be divided into four dimensions to analyse the complicated relationship between different interests and strategies in urban planning. Heritagisation can refer to: the addition of new heritage; reaffirmation of already designated heritage; re-interpretation of already designated heritage; rejection of previous designated heritage.
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| 1336. |
- Sjøvoll, Jarle
(författare)
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Rom for alle - syn for hver enkelt : studier av implementeringen av individuelle opplæringsplaner i norsk skole
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Avhandlingen handler om innføringen av individuelle opplæringsplaner i norsk skole. Avhandlingens epistemologiske forankring er blandet. Den vitenskapsteoretiske orienteringen er i sterkere grad forankret i phronesis enn i episteme selv om jeg forskningsmetodisk relaterer meg til begge begrepene. Avhandlingen er sammensatt av flere delundersøkelser. Resultatene viser at individuelle opplæringsplaner ble innført som ett ledd i omstruktureringen av spesialundervisningen i Norge. Ordningen skulle sikre rettighetene til tilpasset opplæring hos elever med særskilte behov. Det nye er at tiltakene nå kobles sammen med læreplansystemet på en mer formell måte enn tidligere. Ved dette ønsker myndighetene å få bedre styring med spesialundervisningen. I mine delundersøkelser analyseres også ressursbehovet i forbindelse med utarbeidingen av individuelle opplæringsplaner og jeg påviser ulike effekter av dette arbeidet, eksempelvis høyning av lærernes refleksjonskompetanse, øking av "pedagogiske debatter" og at struktureringen av spesialundervisningen endres ved skolene. I avslutnings-kapitlene er det konkludert med at fremtidig spesialpedagogisk tiltaksutvikling i sterkere grad må referere til utvikling av skolen som organisasjon og fokusere på endringsbehov i skolesystemet. Tiltakene må utvikle konteksten for læring.
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| 1337. |
- Skawina, Bartlomiej, 1985-
(författare)
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Load-Haul-Dump operations in underground mines
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The research presented in this thesis addresses several aspects of loading operations inunderground mines, in particular tools and equipment selection. It also addresses the flexibilityof the fleet when subject to substantial disturbances, such as ore pass loss, and proposes integration of the scheduling system with discrete event simulation. The thesis begins with a study of discrete event simulation (DES) tools for loading operations in an underground mining system. The results show the benefits of using simulation but also the drawbacks.The thesis presents an analysis of energy consumption and exhaust gas emissions from diesel and electric LHDs. The results show the potential energy savings with the use of electric LHDs. Next, it focuses on the LHD operations affected by long-term ore pass loss (unavailability). It shows the effects on the production system (the ventilation requirements, production and waiting times when too many LHDs operate in the area affected by an ore pass loss) and highlights the need for a flexible solution and a mitigation strategy. Finally, the thesis studies the integration of ABB’s Ability Operations Management System (OMS) with the SimMine simulation model and how this affects LHD operations. The results show the benefits of using the joined platformas a testbed and decision support system.
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| 1338. |
- Skog, Johan
(författare)
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Characterization of sawlogs using industrial X-ray and 3D scanning
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the Nordic countries, sawlogs are typically sorted upon arrival at the sawmill based on species and dimension. By processing batches of logs with similar size, the sawing process becomes more efficient; the need to change sawing pattern between individual logs is reduced, and the handling of sawn goods is simplified, since the number of different dimensions produced simultaneously decreases. However, since wood is a biological material with great heterogeneity, there will be a large variation in the properties also of boards sawn from logs of similar size. This means that a significant amount of the boards may be carrying unwanted combinations of dimension and grade, so called off-grade products. The problem with off-grade products may be addressed before sawing by the selection of suitable sawing patterns for each log, i.e., using the right logs for the right products. This requires knowledge of the internal quality of the log before sawing. Some information can be obtained from the outer shape measured by an optical three-dimensional (3D) scanner and more detailed information can be obtained using an X-ray log scanner. Today, the use of X-ray log scanners is becoming increasingly common, and most sawmills installing an X-ray scanner already have a 3D scanner present. This raises the question of possible benefits from combining the X-ray and 3D scanning techniques. In this thesis, a method is presented whereby the outer shape of the log measured by a 3D scanner is utilized to estimate the X-ray path lengths through the wood. This converts the X-ray images into green density images of the log, which may in turn be used to calculate quality variables such as heartwood diameter, dry density, moisture content and presence of top rupture. The methods have been tested on Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) sawlogs using X-ray scanners with one or two measurement directions. The developed methods show a great improvement in precision compared to calculations based on uncompensated X-ray images, and most of the algorithms presented in the thesis have now been implemented in industrial scanner software and are ready for use at the sawmills. This will give the sawmill industry new possibilities to control the production of special products where heartwood diameter and density are important and will lead to less waste and improved profitability for the sawmills.The thesis also describes a method where X-ray scanning is utilized to automatically perform parts of the log grading for payment. This method can improve productivity in the sawmills by remedying a severe bottleneck in the production chain. An authorization of this method for semiautomatic log grading for payment is expected to further increase the industry’s interest in X-ray scanning.
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| 1339. |
- Skogsberg, Kjell
(författare)
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Seasonal snow storage for space and process cooling
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The world’s cooling demand has increased considerably during the last decades due to increased population, industrialisation, comfort demands, electronic equipment usage and new building technologies. Conventional cooling is often produced by electrically driven devices. One less prime energy-consuming alternative is to use stored winter cold in snow and ice for cooling during the summer. This ancient technique is feasible in large parts of the world. Different systems for seasonal snow and ice storage exist, i.e. the snow/ice can be stored indoors, on the ground, in the ground and underground. This study focuses on in ground storage, in an open pond, where the cold energy is extracted by water that is cooled by direct contact with the snow. Open pond snow storage must be thermally insulated; hence, different insulation alternatives were discussed. Cutter shavings were studied in laboratory experiments and numerical modelling. The surface melt rate of snow covered with cutter shavings increased with increased solar radiation, air velocity, air temperature, and decreased insulation layer thickness. The evaporation rate contributed significantly to the energy balance. The surface melt rate was similar with initially wet and initially dry wood chips. It was concluded that evaporative cooling is an important part of the thermal insulation qualities of wood chips. It was also found that heat transfer from the rain and ground is usually relatively small. The heat transfer from the ground depends on soil and groundwater properties. The Sundsvall Regional Hospital snow cooling plant in Sweden has successfully operated since 1999. Natural and artificial snow is stored in a slightly sloping, shallow pond of watertight asphalt. During these years, the plant has delivered the main part (77-93%) of the cooling, totalling 655-1,345 MWh. The snow was thermally insulated by a 0.1-0.2 m layer of wood chips. The total coefficient of performance, including construction energy, was 2.0-6.6 times greater than that of a conventional chiller system. The environmental impact of a snow cooling plant and a chiller system was compared, for both existing and “environmentally optimised systems”. Of the existing systems, the chillers had the largest impact concerning climate change, acidification and nitrification, while the snow cooling system meant more photochemical ozone emissions. The dominating impact sources of the snow cooling system were fuel and electricity. In the construction phase, ground insulation had the greatest impact. In future open pond storage, a more compact design (deeper storage) is suggested to reduce maintenance and melt loss. Total cooling costs were estimated to be 0.29-0.47 SEK kWh-1 for a new open pond storage, i.e. lower than that of district cooling. The study also comprised mass loss of freezing water, since repeated freezing and thawing during the spring will evaporate large amounts of water. This was estimated to have little effect on Swedish snow storage, though the loss might be considerable at other locations.
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| 1340. |
- Skär, Lisa
(författare)
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Barn och ungdomar med rörelsehinder : deras uppfattningar om roller, relationer och aktiviteter
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The general aim of this thesis was to describe how children and adolescents with restricted mobility perceived their roles, relations and activities in relation to peers and adults in different settings. The thesis includes six sub-studies, which are based on interviews, observations and field notes with children and adolescents with restricted mobility aged from 6 to 19 years. Using Bronfenbrenner’s theory “the Ecology of Human Development” as the main theoretical framework, the ambition was to understand the children and adolescents’ social world from their perspective. The principal finding was the lack of peers in the children and adolescents’ social network. Furthermore, this tendency of isolation from peers was found to increase during the transition from childhood to adolescence. Their relationships to peers were strained and activities and surroundings in which social contacts could develop were limited. The relationships with peers were also characterised by social barriers in the form of attitudes that resulted in social isolation from the group of persons the disabled children and adolescents most wished to be with. When relations to peers were limited, the disabled children’s social life was restricted to adults. The results further showed that the children and adolescents’ roles and relations often were significantly different from their peers. The children and adolescents’ arrived at a concept of themselves that differed from the way others conceptually saw them. Furthermore, the children and adolescents saw themselves as regular members of their peer group, but the other members of the peer group saw them as different from themselves. Relationships to friends of the same age either were confined or were nonexistent. Relationships to adults were often characterised as ambivalent or asymmetric, i.e. the adults were helpful and supportive while over protective and dominant at the same time. The thesis revealed that, despite the many obstacles facing them, the children and adolescents with restricted mobility had a positive view of their future.
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