| 1. |
- Ferm, Lisa, 1984-
(författare)
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Vocational Students’ Agency in Identity Formation as Industrial Workers
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The overall aim of this thesis is to contribute knowledge about vocational identity formation among students within the industrial programme in Swedish upper secondary education, with a particular focus on their workplace-based learning. To break down the aim, three research questions have been formulated and each is addressed in one or two specific articles. These questions are: (1) What learning strategies do vocational students use to become part of a work community, and how do these strategies relate to the formation of a vocational identity at the workplace? (2) How do vocational students experience their identity formation in relation to a vocation within the industrial sector? (3) How do vocational students handle the division between theoretical and practical knowledge as they learn to become skilled industrial workers? The thesis builds on 53 semi-structured qualitative interviews with Swedish upper secondary vocational students enrolled on the industrial programme. The interviews revolve around the students’ vocational identity formation, with a focus on their workplace-based learning. The students are between 18 and 20 years old and the majority are boys. The findings are analysed through the theoretical lens of situated learning, where identity formation is viewed as a social learning process that takes place through participation in communities of practice. In addition, the concepts of habitus, gender and social categorisation are used as analytical tools to provide a deeper understanding of issues concerning status, power and exclusion in relation to vocational identity formation. The findings reveal that the students’ vocational identity formation is closely connected to the social aspects of participating in workplace communities. Knowledge about the jargon and social norms of the workplace seem to be of more importance for vocational identity formation than knowledge about the concrete working tasks. The study follows the students’ vocational identity formation throughout their vocational learning trajectories, which reveal that vocational identities are formed in heterogenic ways. The students may adopt a committed, flexible or ambivalent approach towards industrial work. Aspects concerning agency and status seem to be crucial for the vocational identification process. The forming of a vocational identity also implies positioning oneself in the hierarchy and division between theoretical and practical knowledge, as well as between masculinity and femininity. The students appear as knowledgeable actors who are aware of the generally low status of industrial work, while simultaneously expressing a great deal of pride in relation to their intended vocations. In the discussion, a model of the students’ vocational identity formation is proposed to capture the interplay between collective and structural dimensions (e.g. social background, class and status hierarchies at school) and students’ agency and strategies in becoming industrial workers. From the findings of this thesis, three main conclusions are drawn: (1) The students form vocational identities through using vocational agency in actively developing strategies for becoming accepted in the workplace community; (2) Workplace-based learning is central for the students’ vocational identity formation, in spite of the relatively short time that the students spend there, compared to the time spent at school; (3) The students’ vocational image awareness, expressed through awareness of, and reactions to, other people’s images of their vocation, constitutes an important part of their vocational identity formation.
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| 2. |
- Lingegård, Sofia
(författare)
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Integrated Product Service Offerings for Rail and Road Infrastructure : Reviewing Applicability in Sweden
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This research aims to explore and propose a more effective management of rail and road infrastructure and the possibility of a more resource-efficient road and rail infrastructure by applying business models based on performance and a life-cycle perspective.There is a lack of efficiency in the Swedish rail and road infrastructure industries - at the same time as the availability of the rail tracks and roads is essential. Rail and road infrastructure have long lifetimes, around 40-60 years, and during these decades regular maintenance and reconstruction are needed to ensure proper function. Large amounts of resources are required to construct the infrastructure, and the overall environmental pressure depends substantially on this.This research is largely based on interviews conducted with the buyer, contractors and design consultants for rail and road infrastructure in Sweden. Literature reviews have been conducted to develop the framework needed to analyze the empirical findings. This research contributes by building on theory in areas such as Integrated Product Service Offerings (IPSOs) and eco-design, and this abstract presents a brief summary of the overall conclusions.Several challenges for rail and road infrastructure in Sweden have been identified, such as the lack of information and knowledge transfer between different projects and actors. This is due to e.g. the use of traditional short-term contracts and conservative cooperate cultures, creating sub-optimizations in management. Increased collaboration, through e.g. partnering, seems to be a promising way to increase the information and knowledge transfer between actors by increasing trust and interaction. In this way, management would be more effective, and by involving contractors in the design phase, more efficient technical solutions could be developed and used. Additionally, increased involvement by the design consultants and an iterative information loop between design, construction and maintenance could also be beneficial. The research indicates that increased cooperation increases trust. In this way, there is a possibility to remove the detailed requirements that prevent new ways of working.Rail and road infrastructure have characteristics, such as the resources used and the importance of availability, that are well-suited for IPSOs. This performance-based business model with a life-cycle perspective provides incentives to optimize the use of resources and provide a holistic view for management that is lacking today for rail and road infrastructure. However, a long-term contract such as an IPSO creates uncertainties. The actors are risk-averse, which is an obstacle in the development of new business models and contract forms. Most of the risks and uncertainties identified are due to lack of experience. This implies that an implementation of IPSOs will have a steep learning curve. Additionally, risk allocation between the actors is important for effective management: too much risk for the suppliers will make them reluctant in developing new solutions, and they will use a risk premium to cover up for the risk.
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| 3. |
- Majumdar Svensson, Orpita
(författare)
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Innovative Polymer Hosts for Solid Lithium-ion Battery Electrolytes
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Current electrolytes used in lithium ion batteries are flammable and volatile organic liquids that are fundamentally unstable at the operational voltage of the cells, posing a significant safety risk. A practical approach to get over this obstacle is to substitute the liquid electrolyte solution with a solid (solvent-free) polymer electrolyte (SPE), which is a solution of a lithium salt in a solid polymer matrix. In the past few decades, polyethers, particularly those based on poly(ethylene oxide) (PEO) have been the subject of extensive research as SPEs. However, numerous researchers have noted inherent limits in the overall performance of PEO and other polyether-based electrolytes, driving the search for electrolytes based on alternative types of polymers. A few of those polymers that can be utilized as prospective polymer hosts for future lithium-ion batteries are introduced in this thesis.Organic carbonates are commonly used as liquid electrolytes, therefore their polymeric counterparts, polycarbonates, are suitable as host materials in SPEs. In contrast to PEO, carbonates show weaker coordination with the lithium ion, which consequently results in faster cation transport. In Paper I, we utilize a metal-free catalyst, diphenylammonium triflate (DPAT), to facilitate the ring-opening polymerization of trimethylene carbonate (TMC). This results in a copolymer, poly(trimethylene carbonate)-poly(trimethylene ether) (PTMC-co-PTME), which has a polymer backbone that possesses both carbonate and ether functionalities.In Papers II and III, we evaluate a new family of SPEs based on poly(β-amino ester)s (PBAEs) by employing aza-Michael addition in the presence of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). We use off-stoichiometric multifunctional short chain acrylates and amines as monomers to synthesize crosslinked polymer electrolyte films through a one-step, dual-curing, metal catalyst and solvent free method. We establish that structural changes in the polymer backbone can be easily introduced by varying the monomers and their concentrations, resulting in enhanced ionic conductivities. This methodology generates zero side products, is highly atom efficient and produces free-standing electrolyte films in a single step.The use of additives in electrolytes is one of the most convenient and affordable ways to improve lithium-ion battery performance without requiring significant modifications. In Paper IV, we use the procedure described in Paper II to explore the effects of different measured concentrations of dimethyl sulfoxide (DMSO) as an additive in PBAE-based SPEs. DMSO has a high donor and acceptor number, making it an effective solvating agent for both the anions and cations in the electrolyte.
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| 4. |
- Svensson, Anna
(författare)
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A Utopian Quest for Universal Knowledge : Diachronic Histories of Botanical Collections between the Sixteenth Century and the Present
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis explores the history of botany as a global collection-based science by tracing parallels between utopian traditions and botanical collecting, from their sixteenth-century beginnings to the present. A range of botanical collections, such as gardens, herbaria and classification systems, have played a central role in the struggle to discover a global or universal scientific order for the chaotic, diverse and locally shaped kingdom of plants. These collections and utopia intersect historically, and are characterised by the same epistemology of collecting: the creation of order through confined collecting spaces or “no-place.” They are manipulations of space and time. Between chaos and order, both seek to make a whole from – often unruly – parts. The long history of botanical collecting is characterised by a degree of continuity of practice that is unusual in the sciences. For instance, the basic technology of the herbarium – preserving plants by mounting and labelling dried specimens on paper – has been in use for almost five centuries, from sixteenth-century Italy to ongoing digitisation projects. The format of the compilation thesis is well-suited to handling the historiographical challenge of tracing continuity and discontinuity with such a long chronological scope. The thesis is structured as a walled quadripartite garden, with the Kappa enclosing four research papers and an epilogue. The papers take a diachronic approach to explore different perspectives on botanical collections: botanical collecting in seventeenth-century Oxford, pressed plants in books that are not formally collections; and the digitisation of botanical collections. These accounts are all shaped by the world of books, text and publication, historically a male-dominated sphere. In order to acknowledge marginalisation of other groups and other ways of knowing plants, the epilogue is an explanation of an embroidered patchwork of plant-dyed fabric, which forms the cover of the thesis.
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| 5. |
- Svensson, Daniel
(författare)
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On Cohesive Modelling of Carbon/Epoxy Composites : Delamination and Fibre Compressive Failure
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Carbon Fibre Reinforced Polymers are widely used in engineering applications where weight saving and high mechanical performance are a key factors. However, an inheren tweakness of laminated CFRP:s is there relatively low resistance to delamination. Therst part of this thesis is devoted to extract cohesive laws associated with delamination.The method is based on fracture mechanical tests and measurement of the displacementeld close to the crack tip. The second part of the thesis is concerned with mixed modecohesive modelling under small scale yielding conditions. Under such loading conditions,a robust cohesive model should conform to Linear Elastic Fracture Mechanics (LEFM). Itis shown that two design rules for mixed mode cohesive laws are sucient to achieve thisproperty. The third part focuses a failure mode entirely dierent from delamination. Theobjective is to determine cohesive laws associated with longitudinal compressive failure.Equilibrium of congurational forces is used for this purpose. Identied congurationalforces are continuously measured by monitoring the displacements eld on the specimen'slateral surface. This allows for identication of the cohesive law.
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| 6. |
- Svensson, Daniel
(författare)
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Regulation of human cell viability by the host defence peptide LL-37
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Accumulating evidence suggests that the main human cathelicidin peptide, LL-37, may influence host cell viability and pro-inflammatory signaling when locally overexpressed. LL-37 has pro-inflammatory properties linked to the development of for example psoriasis, rosacea, SLE and atherosclerosis. However, the importance of LL-37-induced host cell permeabilization and cytotoxic effects are poorly understood. We hypothesize that these effects are implicated in the tissue destruction associated with inflammatory diseases such as chronic periodontitis (CP). CP, the number one reason for adult tooth loss globally, is associated with elevated LL-37 levels. Here, tooth detachment is caused by degradation of the supporting bone. We aimed to investigate effects of LL-37 on osteoblast cell viability in vitro and the underlying mechanism in order to explore the detrimental effects of LL-37 and the possible involvement in tissue destruction associated with CP. In agreement with this, the peptide was found to permeabilize and kill osteoblasts at concentrations relevant for the in vivo situation. Cell permeabilization by LL-37 was associated with LDH release, Ca2+-influx, attenuation of cell viability, accumulation of annexin V positive cells and caspase 3 activation, indicative of apoptosis in MG63 osteoblasts. As LL-37 constitutes a possible drug target, we further investigated compounds and endogenous mechanisms that may serve to inactivate LL-37. We found that the protein p33 (gC1qR) may be added extracellularly to rescue osteoblasts from LL-37-evoked cytotoxicity. Additionally, endogenous p33 appears to be a mean by which host cells are protected from LL-37-induced cytotoxicity, as the extent of the toxicity correlates to p33 expression levels in various host cell types. Host cell sensitivity towards LL-37 may moreover be modulated through up- or down- regulation of p33 expression, mediated through transfection with a pcDNA3.1 expression vector and siRNA. p33 was found in the mitochondria, cytoplasm and in proximity to the cell membrane. It inactivates LL-37 intracellularly, as cell viability but not cellular LDH release is influenced by p33 expression, and additionally, LL-37 co-immunoprecipitates with cytoplasmic p33. This indicates that internalization of LL-37 is critical for host cell cytotoxicity. Furthermore, a comparison of LL-37's effects on various cell types indicates that LL-37-evoked cytotoxicity is not directly correlated to the degree of cell permeabilization.The active form of vitamin D, 1,25D3, is a well-known mediator of LL-37 synthesis, although its possible role in dysregulated expression of LL-37 is yet to be elucidated. Stimulation of LL-37 expressing THP-1 monocytes with 1,25D3 was shown to attenuate cell viability both of co-cultured periodontal ligament (PDL) cells and the THP-1 cells themselves. This effect is reversed by addition of recombinant p33 to the cultures, implicating LL-37 as the mediator of the cytotoxic effect. In skin, RXRα protein levels were found to be critical for LL-37 expression: siRNA mediated silencing of RXRα attenuates 1,25D3-induced stimulation of LL-37 in HaCaT keratinocytes. Furthermore, gene expressions were analyzed in human skin and gingiva biopsies. Skin shows significantly higher LL-37 gene expression compared to gingiva and this difference correlates to RXRα mRNA levels.In conclusion, our study contributes to the mechanistic understanding of LL-37 induced cytotoxicity in host cells, as well as the regulation of LL-37 expression by vitamin D. The in vitro results presented here support the hypothesis that LL-37 may be involved in the tissue destruction, observed locally in inflammatory diseases such as CP.
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| 7. |
- Svensson, Daniel, 1983-
(författare)
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Scientizing performance in endurance sports : The emergence of ‘rational training’ in cross-country skiing, 1930-1980
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Elite athletes of today use specialized, scientific training methods and the increasing role of science in sports is undeniable. Scientific methods and equipment has even found its way into the practice of everyday exercisers, a testament to the impact of sport science. From the experiential, personal training regimes of the first half of the 20th century to the scientific training theories of the 1970s, the ideas about training and the athletic body shifted.The rationalization process started in endurance sports in the 1940s. It was part of a struggle between two models of training; natural training and rational training. Physiologists wanted to rid training of individual and local variations and create a universal model of rational, scientific training. The rationalization of training and training landscapes is here understood as an aspect of sportification, a theory commonly used to describe similar developments in sports where increasing regimentation, specialization and rationalization are among the main criteria. This dissertation adds the concept of technologies of sportification to explain the role that micro-technologies and practices (such as training logs, training camps and scientific tests) have in the scientization of training.This thesis thus sets out to analyze the role that science has played in training during the 20th century. It is a history about the rationalization of training, but also about larger issues regarding the role of personal, experiential knowledge and scientific knowledge. The main conclusions are that the process of scientization never managed to rid training of components from natural, experiential training, and that the effort by Swedish physiologists to introduce rational training was part of the larger rationalization movement at the time. In the end, training knowledge was a co-production between practitioners and theoreticians, skiers and scientists.
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| 8. |
- Svensson, Daniel, 1979
(författare)
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Target Tracking in Complex Scenarios
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is concerned with three important components in target track- ing, namely multiple-model filtering, data association and sensor resolution modeling. For multiple-model filtering, the preferred method has long been the Interacting Multiple Model (IMM) filter, which relies on the assumption that immediate model shifts have the highest probability. In this thesis, an alternative switching model is proposed, which forces the models to persist for at least a model-specific time, yielding a less complex problem in terms of model hypotheses. Further, a state estimation algorithm is derived, which is close to optimal under the model assumption. The proposed filter, called the Switch-Time Conditioned IMM (STC-IMM) filter, is shown to provide better performance than the IMM filter in benchmark scenarios.Traditional tracking algorithms are designed to estimate the states of the targets, while trying to maintain their identities. In this thesis, it is shown how these algorithms can be adjusted to problems where target identity is not relevant. More specifically, the Joint Probabilistic Data Association (JPDA) filter is considered, and two adjustments of it are presented, called the Set JPDA (SJPDA) and the Kullback-Leibler Set JPDA (KLSJPDA) filters. These filters both enable more accurate Gaussian approximations, and provide more accurate state estimates than the JPDA filter when evaluated with a metric that disregards identity. Another approach to the problem is to use Finite Set Statistics (FISST). In the thesis, the results of the first performance comparison of the most prominent FISST-based and traditional filters are presented and discussed.In the development of most tracking algorithms, it is assumed that the targets are always resolved by the sensor. However, when the targets are closely spaced in relation to the sensor resolution, this assumption is not valid, and may lead to decreased tracking performance. This thesis presents a multi-target sensor resolution model, for an arbitrary but known number of targets, which takes resolution effects into account. It is further shown how the model is incorporated into a Bayesian tracking framework, and two alternative JPDA-like filters are presented.
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| 9. |
- Svensson, Daniel
(författare)
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The Bentonite Barrier - Swelling Properties, Redox Chemistry and Mineral Evolution
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Bentonite is planned for use as a buffer material in high-level radioactive waste repositories, where safety assessment is performed for very long periods (100-1000 ka). This thesis focuses on the swelling of smectites in liquid water, and analysis of bentonite from field experiments at Äspö Hard Rock Laboratory, Sweden. Four field experiments were analyzed (Alternative Buffer Material experiment, ABM1, ABM2; Temperature Buffer Test, TBT; and Prototype) with focus on Fe- redox chemistry and formation of trioctahedral smectite. The techniques used were mainly synchrotron X-ray diffraction and X-ray absorption spectroscopy. In ABM1 and Prototype the Fe(II)/Fe-total ratio had increased. In TBT no significant increase in Fe(II) was found; instead the corrosion products were dominated by Fe(III). Formation of trioctahedral clays was found in the iron-bentonite experiments (ABM1, ABM2, TBT), but not in Prototype where the heater instead was of copper. In swelling experiments, Ca-Wyoming montmorillonite was shown to expand and partly form a four-water-layer hydrate at lower temperatures in water. This was studied in more detail, and the influence of divalent interlayer cation, temperature, layer charge, salt and irradiation was investigated. Among the investigated smectites, decreased temperature increased the crystalline swelling until ice was formed. Lower smectite layer charge increased the crystalline swelling. Increasing the Gibbs hydration energy of the divalent interlayer cation increased the crystalline swelling. Introduction of salt in the water partly dehydrated the montmorillonite at 20°C, but minimized the dehydration of montmorillonite upon ice formation at low temperatures (-50, -100°C), especially with CaCl2. It was found that in a gradient of ethylene glycol and water a 21 Å basal distance was formed in the montmorillonite, which was higher than in the pure liquids.
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| 10. |
- Svensson, Daniel, 1973
(författare)
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Towards Product Structure Management in Heterogeneous Environments
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The use of computer support in product development and manufacturing has introduced new possibilities and new requirements for information management. The parts, systems, functions and other elements used to represent the structure of a product form what is called a product structure, which is managed by support from information systems. Due to the disparate requirements posed by the different departments and roles involved in the product development process, several different product structures can exist, and these are typically managed by separate information systems. This thesis deals with the problems that arise in corporate environments where different departments and roles have diverse requirements regarding the product structure, here referred to as heterogeneous environments. The approach taken is to study processes, information, organization and information systems involved in the management of product structures as a unity, called an Engineering Information Management (EIM) system. A framework for the modelling and analysis of EIM systems has been developed during the research. The questions of the research treat: the modelling and analysis of EIM systems, the problems of product structure management in heterogeneous environments, and how to integrate the information systems used. Several studies have been performed, where the integration between information systems has been investigated. This includes the integration of Product Data Management (PDM), Enterprise Resource Management (ERP), Requirements Management (RM) and Software Configuration Management (SCM) systems. The management of product information for products made up of both hardware and software has been further studied by the development of an information model capable of describing the structural elements of such products. The contributions of the research concern both the modelling framework and the integration of information systems. A framework for modelling EIM processes is proposed. It has been shown that different activity domains (e.g. departments or functions) have diverse requirements for product structures, i.e. their breakdown and information content. Strategies for the integration of PDM systems with ERP, RM and SCM systems have been formulated. An information model capable of describing the core constituents of a product structure for multi-technology products is proposed.
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