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- Aaboen, Lise, 1978
(author)
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Incubators and new technology-based firms - A resource-based view of development
- 2006
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Licentiate thesis (other academic/artistic)abstract
- New technology-based firms (NTBFs) are based upon the exploitation of a new technology. This often means that there are few other than the founder who understands the technology, and in addition the firm often aims at serving a market in a new way or operating on a presently non-existent one. Therefore, it can be hard to determine the future potential of NTBFs, and this causes growth constraints on the firm. However, the NTBFs that do survive contribute to industrial and regional growth on a long-term perspective through, for example, knowledge spillovers as well as finding and developing product concepts. The incubator on the other hand can be seen as a provider or mediator accelerating the development of promising NTBFs. As a provider the incubator mobilizes resources and adjusts them to the needs of the particular NTBF. The mediator role can instead be seen when the incubator connects the NTBF to members of the incubators external network.The basis of the resource-based view is that a competitive advantage comes from the heterogeneity in terms of resources between firms. Imitability of valuable resources makes the competitive advantage sustainable. The newness of the NTBFs implies that they are in the process of trying to obtain or develop their resources. These resources include capabilities that determine how well the organization is able to perform a certain task. Furthermore, resources like funding, patenting, human resources and intangible resources are needed. Similarly, the incubator benefits from knowledge workers, funding and continuous improvements of the knowledge base in order to serve the NTBFs and maintain fruitful external relations. Consequently, this thesis has the purpose of exploring how the obtaining of resources link incubators and NTBFs. This exploration includes three papers in which the first two are devoted to the incubator, and the NTBFs respectively, in order to understand the resource needs of these two types of organizations. However, the third paper focuses on the links between the incubator and the NTBF in terms of providing links to external actors. Further, the exploration includes empirical findings from both qualitative and quantitative data that have been gathered within the Swedish incubator program during 1999 and 2005. The concluding discussion suggests that the human and knowledge resources of the incubator increase the external resources and the capabilities of the NTBFs. A successful NTBF in turn improves the human and knowledge resources of the incubator through knowledge sharing and an increased reputation. An increased survival rate of NTBFs will also positively affect the public funding of the incubator. It is in this way that a positive spiral is created where the resources of the incubator accumulate as more and more successful NTBFs are generated. Failing NTBFs will, on the other hand, also make it more difficult for the incubator to obtain and maintain resources. Seeing the connections between incubators and NTBFs in this way further emphasizes the element of path dependency in the development of these organizations. Subsequently, there is also a long-term aspect of the expected results on regions and industries from public investments made in them.
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| 4. |
- Abadikhah, Hossein, 1987
(author)
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Dynamic higher order equations for structural elements
- 2014
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Licentiate thesis (other academic/artistic)abstract
- The subject of this thesis is to derive and evaluate governing equations and corresponding boundary conditions for solid isotropic cylinders and isotropic micropolar rectangular plates. This is achieved by a systematic power series expansion approach, by either adopting a generalized Hamilton's principle or a direct approach.For the solid cylinders a power series expansion in the radial coordinate is adopted. Equations of motion together with consistent sets of end boundary conditions are derived in a systematic fashion up to arbitrary order using a generalized Hamilton's principle. Governing equations are obtained for longitudinal, torsional, and flexural modes. In the case of the isotropic micropolar plate a power series expansion of the displacements and micro-rotations are adopted in the thickness coordinate. Governing equations of motion, for extensional and flexural case, together with consistent sets of edge boundary conditions are derived in a systematic fashion up to arbitrary order with use of the direct approach.Both the governing equations for the solid cylinder and the micropolar plate are asymptotically correct to all studied orders. Numerical examples are presented for different sorts of problems, using exact theory, the present series expansion theories of different order, various classical theories and other newly developed approximate theories. These results cover dispersion curves, eigenfrequencies, various curves of cross sectional quantities such as displacements, stresses and micro-rotations, as well as fixed frequency motion due to prescribed end displacement or lateral distributed forces. The results illustrate that the present approach may render benchmark solutions provided higher order truncations are used, and act as engineering equations using low order truncation.
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| 5. |
- Abadikhah, Marie, 1992
(author)
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Influence of electrode material and stochastic factors on the performance and microbial community assembly in microbial electrochemical systems
- 2022
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Licentiate thesis (other academic/artistic)abstract
- Microbial electrolysis cells (MECs) are systems with microbial communities in the form of biofilms on electrode surfaces. The electrogenic bacteria in the anode biofilm act as catalysts for the oxidization of organic compounds, leading to release of electrons, generation of electrical current, and production of hydrogen and methane at the cathode. In addition to production of energy carriers, MECs can be used for other applications as well; for example, as biosensors to monitor biochemical oxygen demand or toxicity. The performance of MECs is determined by both deterministic and stochastic factors influencing the microbial communities on the electrode surfaces, most of which as still poorly understood. In this thesis, the effects of electrode materials on microbial community assembly and MEC performance was investigated. Two experiments were carried out. In the first, three cathode materials (carbon nanoparticles, titanium, and steel) were compared. In the second, three anode materials (carbon cloth, graphene, and nickel) were compared. The cathode materials had no significant effect on the performance of the MECs, as opposed to the anode materials where carbon cloth MECs had the highest current density and the shortest lag time during startup. The differences seen in lag time of replicate systems at the start of the experiment indicated a stochastic initial attachment of the electrogenic bacteria on the anode. Different microbial communities develop in the biofilms on the anodes and cathodes. Electrogens from the Desulfobacterota phylum dominated the anode, while various hydrogenotrophic methanogens, e.g., Methanobacterium, were found to dominate on the cathodes. Diversity and null model analysis of the electrode communities highlighted stochasticity and not electrode material as the important factor in the community assembly. Network analysis showed that the cathode communities had fewer negative interactions between taxa in comparison to the anode. Since hydrogen gas generated at the cathode surface can diffuse through the biofilm, all microorganisms on the cathode have access to the substrate, reducing the need for competition between species. In contrast, electrogens require a short distance to the anode to be able to use it as electron acceptor. Limited space on the anode and competition between electrogens shaped the anode communities and explain the higher number of negative interactions observed. Based on the findings in this thesis, it is suggested that stochastic factors have more influence than electrode material on the anode community even though there is a selective pressure for electrogenic bacteria.
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| 8. |
- Abdulahovic, Tarik, 1976
(author)
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Analysis of High-Frequency Electrical Transients in Offshore Wind Parks
- 2009
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Licentiate thesis (other academic/artistic)abstract
- In this thesis, a study of high frequency electromagnetic transient phenomena is performed. Models of various components needed for simulations of high frequency transients, such as transformers, cables and breakers are developed. Also, measurements of high frequency transients are performed in the cable laboratory in ABB Corporate Research in Västerås, Sweden for the purpose of parameter estimation of models and for verification of simulations. Some critical cases where the voltage surges of the magnitude and/or rise time above basic lightning impulse voltage level appear, are identified. Also, some transient protection schemes are analyzed and the performance of different transient mitigation devices is studied. Furthermore, the energizing transient of the Utgrunden wind park is analyzed and the simulation model is verified using the measurements.The energizing transient simulation predicted accurately the magnitude and the frequency of the transient voltages and currents. Simulations of the high frequency transients are in a very good agreement with the measurements obtained in the cable lab. Simulations predicted accurately critical surges with the highest magnitude and matched with good accuracy surge waveform recorded during the measurements. During the testing and simulations, surges which exceed the basic lightning impulse voltage level of dry-type transformers specified by IEEE standards, both in magnitude and rise time are observed even when surge arresters are used. It is confirmed both in simulations and measurements that use of additional transient protections devices such as surge capacitors and RC protection, decreased the magnitude of surges below the critical level.
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- Abdurrokhman, Iqbaal, 1991
(author)
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Proton conducting ionic liquids-Binary mixtures and structural modifications
- 2020
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Licentiate thesis (other academic/artistic)abstract
- Proton conduction is a phenomenon of fundamental importance for biological and chemical systems, such as in photosynthesis and aerobic respiration. Proton conduction is also key in the proton exchange membrane fuel cell, a clean electrochemical device that converts chemical into electrical energy. The archetypical proton exchange membrane is currently a perfluorinated polymer with pending acidic groups. The fuel cell technology is presently at renewed focus in the commercial sector, and consequently also in the scope of research and development programs. In order to enable the development of more sustainable proton exchange membrane fuel cells, new requirements have been set that for instance target operation at higher temperatures and anhydrous conditions. In this context, protic ionic liquids have been highlighted as interesting next-generation electrolytes with the potential to assist proton conduction. Protic ionic liquids are a subset of ionic liquids, also known as low temperature molten salts, entirely composed of ions and displaying very low vapor pressures. Moreover, a protic ionic liquid has an exchangeable proton and is able to establish extended networks of hydrogen bonds. Understanding the dynamics of this local structures is fundamental to design new protic ionic liquids able to sustain a fast proton motion decoupled from the diffusion of the ionic species. To achieve such a dynamical behavior we have investigated two different approaches, that is i) mixing a protic ionic liquid candidate with a co-solvent (here ethylene glycol) able to participate in the hydrogen bonds and ii) modifying the molecular structure of the cation (here by alkyl chains of length (n) varying from ethyl (n=2) to dodecyl (n=12)) in a series of imidazolium based protic ionic liquids. The local intermolecular inter- actions, the nano-structuration as well as ionic and protonic dynamics have been investigated by suitable techniques that include vibrational spectroscopy, NMR spectroscopy, diffusion NMR, impedance spectroscopy and X-ray scattering.
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- Abedi, Hamidreza, 1979
(author)
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Development of Vortex Filament Method for Aerodynamic Loads on Rotor Blades
- 2013
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Licentiate thesis (other academic/artistic)abstract
- Wind power is currently one of the most reliable new energy sources serving as an alternative tofossil fuel generated electricity and is known as a widely distributed clean and renewable sourceof energy. It is now the world’s fastest growing energy source and has also become one of themost rapidly expanding industries.The aerodynamics of a wind turbine are governed by the flow around the rotor, where theprediction of air loads on rotor blades in different operational conditions and its relation to rotorstructural dynamics is crucial for design purposes. One of the most important challenges in windturbine aerodynamics is therefore to accurately predict the forces on the blade, where the bladeand wake are modeled by different approaches such as the Blade Element Momentum (BEM)theory, the vortex method and Computational Fluid Dynamics (CFD). Here, the application ofthe vortex filament method for wind turbine aerodynamic performance is used. Different blademodels such as the lifting line and the lifting surface with prescribed and free wake models arestudied. The main purpose is to find the proper combination of blade and wake models for theaerodynamic loads as well as the computational time in order to develop an accurate and efficientaerodynamic tool. The results of the different approaches are compared with the BEM methodand GENUVP code (see the acknowledgments).
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