| 61. |
- Nyberg, Johan
(författare)
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Music Education as an Adventure of Knowledge. : Student and Teacher Experience as Conceptualizations of Musical Knowledge, Learning and Teaching
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis by publication explores students’ and teachers’ conceptualizations of musical knowledge and learning within the context of the national Arts programme in Swedish upper secondary school. The point of departure is pragmatic ontology and epistemology, emphasizing a holistic view of education as communication and a democratic necessity. Using narrative inquiry and participatory action research approaches, two qualitative, empirical studies have been performed, revolving around the idea of students and teachers as agents within an externally controlled practice, and concerns issues of assessment, accountability and professionalism. The empirical material emanates from a mixed set of methods, including focus group interviews with 30 students and a participatory action research project with a core group of seven music teachers – all recorded in audio and transcribed on micro-level. The analysis was performed as narrative analysis and analysis of narratives (students), and text-analysis (teachers). The results show that both students and teachers have a multifaceted understanding of musical knowledge and learning. While the students’ experience of conceptualizing is one of novelty, the teachers express time and communication, both with peers and students, as necessities to be able to act professionally – including equivalent and legally certain assessment. Given the strong emphasis within public education on accountability, there is a great risk of both learning and teaching compliance. The results of this research show that students and teachers are curious, and have the will as well as the ability to conceptualize musical knowledge and learning in the form of a professional language. Taking the chance, as well as being given the opportunity, to share their experiences, upper secondary music education may very well become an adventure of knowledge.
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| 62. |
- Ohlin, Lindsay
(författare)
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An in-situ ATR-FTIR Spectroscopy Study of Adsorption in MFI Zeolites : A step towards effective upgrading of biofuels
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Global warming is believed to be caused by the extensive emission of greenhouse gases, for example carbon dioxide, into the atmosphere by combustion of fossil fuels, such as coal, oil and natural gas. To reduce the emission of carbon dioxide and hence avoid global warming, alternative fuels derived from renewable resources are desired. Another reason for the worldwide interest in finding alternative fuels is that the reserves of the fossil fuels are limited and the oil and gas sources will eventually run out. Biogas and biobutanol are renewable biofuels which are interesting alternatives to fossil fuels. Biogas is produced during degradation of organic material forming a mixture of mainly methane and carbon dioxide with water as a common trace component. Biobutanol is produced from ABE (acetone, butanol and ethanol) fermentation of biomass. Purification of biogas and biobutanol is essential to increase the heat value of the fuels. Traditional purification processes are energy demanding and expensive. Therefore, other separation processes are currently sought for. Zeolites are promising alternatives due to their great potential both as selective adsorbents and as membranes. Due to the unique pore structure, zeolites are capable of separating components based on their adsorption properties. In the present work, single component adsorption of biogas components such as methane, carbon dioxide and water in zeolite ZSM-5 was studied as well as adsorption of water and butanol in silicalite-1 using in-situ ATR-FTIR spectroscopy. The method was successfully further used to study multicomponent adsorption. For single gas adsorption experiments, recorded infrared spectra of adsorbed methane, carbon dioxide and water showed characteristic, well separated, bands for each gas. Adsorbed concentrations were determined from the recorded infrared spectra. The Langmuir model was fitted to the adsorption isotherms and the model matched the experimental data very well. The fitted Langmuir parameters obtained in the present work was in agreement with values reported in the literature. For multicomponent adsorption experiments, the Ideal Adsorbed Solution Theory (IAST) was used to predict the adsorbed concentrations of methane, carbon dioxide and water using the single component adsorption isotherm parameters as input. In general, the IAST was shown to be a fairly good model for predicting the adsorbed concentrations of methane and carbon dioxide from binary mixtures. For the amount of adsorbed methane from mixtures including water, the IAST predicted the values fairly well. However, for mixtures containing water and carbon dioxide, the IAST could not fully describe the adsorption behavior of the two components. The CO2/CH4 adsorption selectivity was determined for various gas compositions and temperatures showing a general increase in the selectivity with decreasing temperature. This indicates that the separation of carbon dioxide from biogas should be more efficient at lower temperatures. Compared to the literature, the selectivity observed in the present work is relatively high indicating that Na-ZSM-5 may be an effective membrane material for upgrading biogas. Moreover, butanol was preferentially adsorbed over water in silicalite-1, indicating that silicalite-1 may be a promising material for recovery of butanol from dilute water solutions.
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| 63. |
- Pavasson, Jonas
(författare)
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Simulation-Driven Development for Increased System Reliability
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The product development process at industrial companies has traditionally focused on hardware-oriented solutions. However, a current trend is to extend business offers to include more service-oriented solutions e.g., functional product business models. A functional product typically includes the four main constituent’s hardware, software, service support system and management of operation. Availability is one critical property for functional product businesses which the customer and provider must agree upon. Hence, performing simulations for functional product development and operation enables the possibility for functional product availability prediction andincreases the possibilities for business offerings. Functional product availability is a function of reliability and maintainability. Today, many companies measure the strength of the hardware product in terms of durability or life length. However,measuring strength in terms of reliability, which is based on a statistically significant basis, supports the functional product development process. Simulations have generally been used to verify existing solutions; therefore, simulation-driven design strategies have been proposed to more rapidly converge on optimal solutions i.e., simulations are used to drive the development rather than simply verify suggested solutions.Today, measured data or estimated data are often used as input to reliabilityprediction methods e.g., fault tree analysis or Bayesian network. When designing new hardware systems, concepts need to be evaluated by means of reliability, but such data may not exist and prototypes often need to be manufactured, which is expensive and time-consuming. A combination of deterministic and probabilistic simulations can be used to derive needed input data for reliability prediction methods i.e., concepts can be evaluated by means of reliability in early stages of the functional product development process, even before a physical prototype is manufactured. The objective of the work presented in this thesis is to develop a simulation-drivenreliability prediction methodology for product development processes.This methodology shall be applied in early phases of existing product development processes, especially to generate, evaluate and select concepts in terms of reliability, to be used as a decision basis for systems solutions. Further, this methodology takes important variations into account and includes a combination of deterministic and probabilistic simulations.The conducted research is based on theories regarding the functional productdevelopment process, product development methodologies (e.g., stage-gated process), reliability prediction methods (e.g., fault tree analysis), deterministic simulation methods (e.g. rigid body dynamics) and reliability engineering (e.g., probability and reliability theory, distribution functions and Monte Carlo method). The research presented in this thesis followed a 5-step procedure including as-is study, to-be scenario development (simulation-driven methodology and a future functional business situation are described), methodology development, methodology verification (through case studies) and methodology validation (through system testing).Existing reliability methods were evaluated according to suitability in differentdevelopment phases during the as-is study. Fault tree analysis and probabilistic variation mode and effect analysis were found to give accurate results due to use of objective input data. It can be concluded that deterministic simulations (such as rigid body dynamics or welding sequences) can be used to derive input data to be used for probabilistic reliability prediction methods. Probabilistic variation mode and effect analysis can be used to derive a safety factor when designing systems, based on components variation contribution. Hence, a method has been developed based on probabilistic variation mode and effect analysis to derive system reliability. The method uses a distribution function (Normal distribution) and the variation contribution from included components. A method based on deterministic simulations to derive component reliability information has further been developed. This method takes different variations intoaccount and through a series of simulations, input data for system reliability (such as fault tree analysis and Bayesian network) can be derived.A simulation-driven hardware system reliability prediction methodology wasdeveloped, including both deterministic and probabilistic simulation models and methods. The methodology is used to predict hardware system reliability in early phases of the functional product development process and to partly exclude hardware system testing. The methodology takes into account component variations when a limited amount of information exists. The simulation-driven methodology will further be implemented in the company product development process. A case scenario was developed for the simulation-driven mobility function methodology. The methodology manages an increased amount of multidisciplinary interactions to combine deterministic and probabilistic simulation, both in parallel and coupled, within and between the four main constituents. The simulation-driven methodology is primarily focused on mobility functions but is more general and canpartly be used in the simulation-driven methodology for hardware system reliability prediction.
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| 64. |
- Persson, Curt
(författare)
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Hjalmar Lundbohm : En studie om ledarskap inom LKAB 1898-1921
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The thesis has as main purpose to study the influences that affected LKAB's first manager Hjalmar Lundbohm (1855-1926) in his leadership, both in mining operations and within the social structure, and how Lundbohm as a leader utilized his network. The study is implemented as a scientific biography. Previous research has dealt with Lundbohm’s role as leader and community builder in peripheral ways within larger histories, but no comprehensive analysis of Lundbohm as a leader and network builder has been made.With the focus on an in-depth description of Lundbohm as a person and his role as a leader, the thesis further aims to contribute to a better understanding of the prerequisites that existed when the mining activities in Kiruna and Tuolluvaara started and as the two societies were built up. The hope is also that the analysis of this leadership can serve as a description of the individual leader’s significance for corporate development and leader’s engagement in social issues.Lundbohm appeared as leader at a time when the patriarchal leadership was about to be replaced by a leadership under greater professionalisation, where the requirement of specialist expertise in the specific business area had increased. At the same time Lundbohm’s authority as a leader in LKAB was questioned even before the First World War, because of the outdated patriarchal leadership style he exercised.Outside of LKAB Lundbohm was perceived as a strong patriarchal leader. In connection with his burial some of the speakers expressed that during Lundbohm’s life he had intentionally cultivated an image of himself as the patriarchal protector as well as leader of the mining community. His legendary status was already solidified immediately after his death.The thesis questions the image of Kiruna as a utopian society, revealing other perspectives which expose the differences in standard between the different social components, town plan, SJ residential areas, LKAB's own residence establishment, and Tuolluvaara.Keywords: patriarchal, network, leadership, utopian society, Kiruna, LKAB,
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| 65. |
- Pettersson, Annelie
(författare)
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Measurement of excellence and cost in a supply chain
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This Doctoral Thesis addresses the topic of measurement of excellence and cost in a supply chain. In this thesis, a framework for monitoring and analysis of cost in the supply chain is developed. A model for analyzing excellence in a supply chain is also developed. The work aims to facilitate improvements and to improve decisionmaking regarding Supply Chain Management (SCM) and excellence and cost improvements in supply chains. The thesis contains an introduction, a literature review and five papers. The first paper considers performance measurements in supply chains within companies having business in Sweden. An empirical study was initiated in order to investigate what performance measurements they use to measure the performance in the supply chain. Main focus has been on excellence and cost. Interviews with supply chain professionals within the selected 30 companies have been conducted in Sweden. In the second paper a framework is suggested for measuring cost in the supply chain. The framework defines Supply Chain Cost (SCC). Total SCC is the sum of Manufacturing cost, Administration cost, Warehouse cost, Distribution cost, Capital cost and Installation cost. The third paper considers. An Average Logistic Index, ALi , was suggested as a method for measuring excellence in the supply chain. This index combines the cost concept and the customer service concept. In paper IV are the SCC framework from paper II and the excellence model in paper III used in a framework for evaluating changes in a supply chain. Two scenario analysis are based on a five step approach measuring SCC and customer service measures, delivery precision and lead-time, before and after a performed or planned change. Paper V considers how offshoring and outsourcing activities are affecting excellence and SCC in the supply chain. Ten managers from different companies were interviewed. Pitfalls when handling decisions about offshoring and outsourcing and criterias for successful offshoring and outsourcing were identified. The papers in this thesis can be used in different ways and in that way help companies in taking the right decisions about improvements in the supply chain. People within the industry who are active in the supply area would then get models and frameworks for measuring excellence and SCC in the supply chain. Implementation of the models and frameworks are recommended to be implemented in Enterprise Resource Planning (ERP) systems in order to simplify and secure the measurement of excellence and SCC in the supply chain.
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| 66. |
- Petursson, Hans
(författare)
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Design of steel piles for integral abutment bridges
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In 1999 research was started at Luleå University of Technology with the purpose to collect experiences from USA and UK on bridges with integral abutments and transfer the experience to Swedish conditions. Since then at least 20 integral bridges with one row of piles under each abutment have been built in Sweden and the European research project INTAB has been completed. Most of the bridges are short and it seems to be difficult to design integral bridges that are longer than 40 m. The reason for this being that piles in integral abutment bridges can experience severe strain during service due to soil restraint and annual fluctuations in bridge temperature, which displace and rotate the end of the pile that is clamped to the superstructure. Most design codes do not allow strains exceeding the yield point at the serviceability limit state (e.g. EN 1993-2). This will limit the possibility to build longer integral abutment bridges founded on steel piles. Since bridges are designed to be used 100 years or more, the strains caused by the annual temperature variations can be considered as a low cycle fatigue problem.The aim of this thesis is to improve the method to design steel piles in integral abutment bridges. This means that the designer with less effort should be able to make a safer or equally safe design as before by using the methods described in this thesis. The thesis describes how the analysis of piles of integral abutment bridges can be done. In order to study how steel piles in integral abutments are used and how they behave an international workshop was arranged in Stockholm (Collin et. al. 2006), a literature study was conducted, a bridge was designed, built and monitored and laboratory tests were made. With the results from the research activities as base a design method is suggested.
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| 67. |
- Pupure, Liva
(författare)
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Non-linear model applied on composites exhibiting inelastic behavior: development and validation
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The polymeric composite materials are in high demand by industries where light and strong materials are required. Although manmade fiber (e.g. glass, carbon, aramid fibers) are most often used to reinforce polymers, natural fibers due to their environmental friendliness and sustainability have been also considered. Natural fiber composites have shown to have great potential as a substitute for conventional glass fiber materials. However, bio-based composites exhibit highly non-linear behavior, besides they are very sensitive to elevated moisture and temperature. Therefore, careful design and optimization of composite properties defined by constituents, composition and internal structure is needed to meet requirements of real-life applications. This can be done by using accurate models that can take into account factors responsible for inelastic behavior of these materials. The initial part of this thesis is dealing with development of phenomenological approach to predict inelastic behavior of composites in tension. Viscoelasticity and viscoplasticity was analyzed in short term creep tests and modulus degradation in stiffness degradation tests. Schapery’s model for viscoelasticity and Zapa’s model for viscoplasticity was used to characterize nonlinearity. This method was then validated on short, randomly oriented fiber composites with different cellulosic fibers (flax, viscose) and bio-polymers (PLA, Lignin). The elastic modulus, tensile stress-strain curves and failure were analyzed at different humidity and temperature levels. Results showed high sensitivity to moisture and temperature and highly non-linear behavior of these materials. Modeling showed good agreement between experimental data and simulations.Since there is need for simulations of strain controlled tests, this model was rewritten in inverted incremental form. Simulations of stress-strain curves showed, that predictions are more accurate, when characterization of viscoelastic and viscoplastic parameters was done at stresses close to failure. However, due to creep rapture it was not always possible to characterize material at high stresses and in this case viscoelastic functions have to be extrapolated. The stress-strain curves can be then used to further adjust extrapolation of model parameters.The model developed in the first part of the thesis proved to be capable of predicting behavior of short fiber composites with good accuracy. However, in order to carry out simulations input parameters have to be experimentally obtained and it has to be done for every composite that is studied. The second part of this thesis is dedicated to development of constitutive model which uses parameters of constituents to predict behavior of material with any composition. This model then is applied on semi-structural natural fiber composites consisting of bio-based resins reinforced with continuous cellulosic fibers. Mechanical properties of different bio-based thermoset resins and regenerated cellulose fibers have been analyzed. Results showed comparable properties of bio-based and synthetic epoxy resins, even at elevated humidity levels, but high scattering of properties from sample to sample. They also showed that bio-based resin exhibit limited non-linearity whereas regenerated cellulose fiber is highly non-linear.In order to avoid large scatter typical for bio-based materials and improve accuracy of the model, methodology for parameter identification for viscoplastic model with use of only one sample has been suggested.The objective here is to simulate strain controlled tests and the most convenient way to do it is with Schapery’s strain formulation model. The parameters for such model can be obtained from relaxation tests, where viscoelastic strain is kept constant but due to presence of viscoplastic strain component such experiments are difficult to perform. Instead, constituents exhibiting viscoplastic behavior have been characterized in creep and viscoelastic parameters for Schapery’s strain formulation are obtained from simulations of relaxation tests with inverted incremental model. Then these parameters are used to simulate behavior of composite subjected to iso-strain conditions.
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| 68. |
- Ranängen, Helena
(författare)
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Advancing CSR in the mining industry : A stakeholder and management system approach
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The concept of corporate social responsibility (CSR) is often defined as the integration of social and environmental concerns in a company’s operations and in its interactions with stakeholders on a voluntary basis. It is commonly accepted that extractive industries are at the cutting edge when it comes topractising CSR and that CSR is especially important in the mining sector. CSR needs to be implemented at every level of an organization if it is to have any meaningful impact. In this respect, scholars call for research on the practical rather than the policy level of CSR and for research viewed from an internalrather than an external standpoint. Established management systems are claimed to be useful for CSR practice and frameworks are based on various standards. The benefits of integrating all the aspects of CSR into one sustainability management system (SMS) are often highlighted. However, critical researchersbelieve that SMS would benefit from an externally focused stakeholder-driven and value-based approach, and that instead of ‘doing things right’ the focus should be on ‘doing the right things’, in that companies are often confronted with a range of stakeholders. In line with the call for practical research, thisthesis focuses on stakeholder management within the context of management system thinking. The purpose of this thesis is to explore how the extractive industry in general and companies in the metal and mining industry in particular practise CSR and how this management can be developed. The case study method was chosen as the research strategy and two single case studies in the mining industry were designed. The research began with a literature review and the collection of case study data consisting of documentation, interviews and interactive workshops. The most comprehensive and applied CSR practice is found in the oil industry. The forestry sector mainly seems to practise CSR through environmental issues, while mining companies focus primarily on community involvement and development and environmental issues.Both the case companies have comprehensive policy frameworks in place for CSR and well implemented work systems for labour practices and the environment. This indicates that certified management systems are effective tools for CSR. However, other important CSR issues, such as fair operating practices and community involvement and development, fall outside the scopeof the adopted management system. Therefore, management systems need to be supplemented in order to integrate sustainable development more fully. Both case studies show that ISO 26000 is useful for evaluating and improving a company’s CSR practice. Case study II demonstrates that stakeholder theory iseasily practised and contributes to the development of CSR practice, at least in the planning phase of the PDCA methodology, i.e. the identification of stakeholders and stakes, the estimation of ‘who and what really counts’ and the development of effective strategies to best manage stakeholders. The path from theory to practice also generates interesting discussions when a company looksat stakeholders from different perspectives.
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| 69. |
- Rönnqvist, Hans
(författare)
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On the Assessment of Internal Erosion of Dam Cores of Glacial Till
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The objective of this study is twofold; on the one hand it investigates the susceptibility to suffusion of glacial till, and, on the other, it presents approaches to evaluate internal erosion susceptibility of dams composed of this type of core soil. Concentrated leak erosion, backward erosion, contact erosion, and suffusion erosion are the mechanisms associated with the initiation of internal erosion. How these interplay in the continuation phase is still a relatively unresolved issue. In engineering practice, these mechanisms have all been seen in dams with glacial till cores; backward erosion activity as seen in Juktan dam, Juklavatn dam, Grundsjöndam, Wreck Cove dam, and in Brodhead dam; possible suffusion as seen in Lövön dam and in Stenkullafors dam; and, furthermore, signs indicating concentrated leaks, such as in Songa dam. A laboratory program of tests was performed on four natural, non-plastic glacial till soils from the core or its borrow area of existing earth dams in Sweden, and on eight mixtures based on these tills, making in total 12 tests. The longest running for 77 days, and the highest applied gradient was 9.5, in bounds of what can occur in dam cores. The tests revealed that gradations of low fines content (< §15–20%), low sand fraction (< §20%), and high gravel fraction (> §60%) are susceptible to suffusion. These are grading characteristics present in the coarse end of the envelope of glacial till cores in many existing dams. Available state-of-the-art assessment criteria for internal stability were evaluated in reference to these experimental data, yielding a modification to the Kenney-Lau adaptation by Li-Fannin. Furthermore, a screening tool for the assessment of internal erosion of dams is proposed, i.e., the unified-plot approach, which combines attributes of the filter gradation and the probable occurrence of internal erosion in a dam. Given the variety of potential mechanism interplaying in the internal erosion of dams with cores of glacial till, it lend confidence to an assessment approach which addresses, susceptibility to several mechanisms.
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| 70. |
- Sayyaddelshad, Saleh
(författare)
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Robust observer design for a class of nonlinear systems: LMI approach
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Observer design for nonlinear systems is a well-known problem in control theory that has been studied from different perspectives. Because the system state variables are generally not always available, state estimation is an essential task in many control applications, which is why this problem has attracted considerable attention from researchers and is the main focus of this thesis.Knowing that no mathematical system can exactly model a physical system, as a control engineer we must be aware of how modeling errors might adversely affect the performance of a control system. From the observer perspective, time-delays, uncertainties and unknown inputs are familiar factors that deteriorate the observer performance on the way of design, analysis and synthesis of any type of observer. Every general observer design should be able to treat all (or at least some) of these issues explicitly and provide quantitative and qualitative results about their impact on the observer performance: consequently, the concepts of robustness, robust performance and robust design have recently become common phrases in the literature and constitute an integral part of research on observer design.Compared to the typical linear systems, observer design for nonlinear systems subject to all the aformentioned deteriorative properties presents a greater challenge for control engineers and researchers. In this thesis, the problem of observer design for a class of nonlinear systems, both discrete and continuous-time, subject to time delay, structured uncertainty and unknown inputs, is investigated. The study shows that by using the upper and lower bounds of the time delay, this parameter can be excluded in the observer structure under some constraints. Moreover, a novel method for designing an Unknown Input Observer (UIO) for a class of nonlinear systems is proposed, which makes the observer capable to satisfy desired performance even inthe presence of unknown inputs. Based on the UIO structure, one step further is taken, and a multiobjective optimization approach for state estimation and unknown input reconstruction is proposed that makes the designed observer not only robust against unknown inputs but also able to reconstruct them under some provided linear matrix inequality (LMI) conditions. In light of linear algebra, note that LMI serves as an important tool in this thesis, significantly facilitating the proposed observer designs.
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