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- Brandell, Daniel, 1975-
(författare)
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Understanding Ionic Conductivity in Crystalline Polymer Electrolytes
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Polymer electrolytes are widely used as ion transport media in vital applications such as energy storage devices and electrochemical displays. To further develop these materials, it is important to understand their ionic conductivity mechanisms. It has long been thought that ionic conduction in a polymer electrolyte occurs in the amorphous phase, while the crystalline phase is insulating. However, this picture has recently been challenged by the discovery of the crystalline system LiXF6∙PEO6 (X=P, As or Sb) which exhibits higher conductivity than its amorphous counterpart. Their structures comprise interlocking hemi-helical PEO-chain pairs containing Li+ ions and separating them from the XF6- anions. The first Molecular Dynamics (MD) simulation study of the LiPF6∙PEO6 system is presented in this thesis. Although its conductivity is too low for most applications at ambient temperature, it can be enhanced by iso- and aliovalent anion doping. It is shown that the diffraction-determined structure is well reproduced on simulating the system using an infinite PEO-chain model. The Li-Oet coordination number here becomes 6 instead of 5; minor changes also occur in the polymer backbone configuration. The crystallographic asymmetric unit and diffraction profiles are also reproduced. On simulating a shorter-chain system (n=22), more resembling the real material, the structure retains its double hemi-helices, but the polymer adopts a more relaxed conformation, facilitating the formation of Li+-PF6- pairs. Infinite-chain simulation shows the ionic conduction to be dominated by anion motion, in contrast to earlier NMR results. The effects of doping are also reproduced. Shortening the polymer chain-length has the effect of raising the transport number for lithium, thereby bring it into better agreement with experiment. It can be concluded that it is critical to take polymer chain-length and chain-termination into account when modelling ionic conductivity mechanisms in crystalline polymer electrolytes.
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| 3. |
- Difs, Kristina
(författare)
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District Heating and CHP : Local Possibilities for Global Climate Change Mitigation
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Global warming, in combination with increasing energy demand and higher energy prices, makes it necessary to change the energy use. To secure the energy supply and to develop sustainable societies, construction of energy-efficient systems is at the same time most vital. The aim of this thesis is therefore to identify how a local energy company, producing district heating (DH), district cooling (DC) and electricity in combined heat and power (CHP) plants, can contribute to resource-efficient energy systems and cost-effective reductions of global carbon dioxide (CO2) emissions, along with its customers. Analyses have been performed on how a local energy company can optimise their DH and DC production and what supply-side and demand-side measures can lead to energy-efficient systems in combination with economic and climate change benefits. The energy company in focus is located in Linköping, Sweden. Optimisation models, such as MODEST and reMIND, have been used for analysing the energy systems. Scenario and sensitivity analyses have also been performed for evaluation of the robustness of the energy systems studied. For all analyses a European energy system perspective was applied, where a fully deregulated European electricity market with no bottlenecks or other system failures was assumed.In this thesis it is concluded that of the DH-supply technologies studied, the biomass gasification applications and the natural gas combined cycle (NGCC) CHP are the technologies with the largest global CO2 reduction potential, while the biomass-fuelled plant that only produces heat is the investment with the smallest global CO2 reduction and savings potential. However, the global CO2 reduction potential for the biomass integrated gasification combined cycle (BIGCC) CHP and NGCC CHP, the two technologies with highest electricity efficiencies, is highly dependent on the assumptions made about marginal European electricity production. Regarding the effect on the DH system cost the gasification application integrated with production of renewable biofuels (SNG) for the transport sector is the investment option with the largest savings potential for lower electricity prices, while with increasing electricity prices the BIGCC and NGCC CHP plants are the most cost-effective investment options. The economic outcome for biomass gasification applications is, however, dependent on the level of policy instruments for biofuels and renewable electricity. Moreover, it was shown that the tradable green certificates for renewable electricity can, when applied to DH systems, contribute to investments that will not fully utilise the DH systems’ potential for global CO2 emissions reductions.Also illustrated is that conversion of industrial processes, utilising electricity and fossil fuels, to DH and DC can contribute to energy savings. Since DH is mainly used for space heating, the heat demand for DH systems is strongly outdoor temperature-dependent. By converting industrial processes, where the heat demand is often dependent on process hours instead of outdoor temperature, the heat loads in DH systems can become more evenly distributed over the year, with increased base-load heat demand and increased electricity generation in CHP plants as an outcome. This extra electricity production, in combination with the freed electricity when converting electricity-using processes to DH, can replace marginal electricity production in the European electricity market, resulting in reduced global CO2 emissions.Demonstrated in this thesis is that the local energy company, along with its customers, can contribute to reaching the European Union’s targets of reducing energy use and decreasing CO2 emissions. This can be achieved in a manner that is cost-effective to both the local energy company and the customers.
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| 4. |
- Götherström, Anders, 1969-
(författare)
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Acquired or inherited prestige? : molecular studies of family structures and local horses in Central Svealand during the Early Medieval period
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This is a study of the role of inheritance among the élite in Early Medieval central Svealand and the possibility to study it by molecular genetic methods. The study is a part of the research project Svealand in the Vendel and Viking periods (SIV). The study rests on classical as well as a new type of source material.Hypotheses are built on the results from a research tradition resting on more than a century of data gathering and analysis. The boat cemeteries in central Svealand hold a central position in this work. Several models have been constructed over the years to explain the appearance of these special and often rich remains. In this work they are discussed in terms of inherited or acquired status, the status that gave the individual the right to such burial. Since these sites have often been discussed in terms of control of northern trade routs, a discussion on ethnicity is inevitable. A distinction between genetic and cultural belonging is made.To test the models, built upon classic archaeological research, molecular genetics is applied to the material. A variety of such molecular systems exist for studies on modern material. Some of them have been selected and heavily modified to be applicable to archaeological material. Systems based on maternally as well as paternally and Mendelian inheritances are used. One of the goals in the methodological work has been to establish which of the methods that may reveal relevant information if applied to archaeological material.Bone material from humans as well as from horses was used to test the models. The human material was mainly gathered from excavations of boat cemeteries in central Svealand, but also from an early Christian site in southern Norrland. The horse material was from a wider geographical area, including central Svealand as well as the Baltic islands Öland and Gotland, and sites in Estonia. The material was mainly from contexts of a high social status, but also, to a much lesser extent, from more common society levels. The results reveal an archaeological potential in the genetic studies of ancient bones. Genetic relations were identified on several cemeteries (Badelunda, Alsike and Björned), but also individuals with no genetic relation to the others were identified (Alsike and Björned). Horses of different sexes and with different maternal origin were also identified.The results indicate that the kin was an important feature in the upper class during the Early Medieval period in central Svealand. The kin probably had a higher importance than gender belonging. The studied horses reveal a similar situation where features other than the sex seems to have been important. However, the family seems to have been an open unit where it was possible for outsiders to enter and become a part. Thus, inheritance was important, but it was possible for an individual with deviating background to reach a desired position in other ways. There was no absolute connection between social status and genetics. As for one of the main status object, the horse, a dynamic and continuous distribution is suggested, either based on trade or on a gift system.
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| 7. |
- Kazen, Thomas, 1960-
(författare)
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Jesus and Purity Halakhah : Was Jesus Indifferent to Impurity?
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- At the end of the Second Temple period, ritual purity came to play an increasing role in Jewish society. Purity laws were interpreted and expanded, and sources of impurity were generally avoided by many. Signs of that development are discussed in this study and put forward as arguments for an expansionist trend, gaining in influence and support from the common people. Jesus’ attitude to impurity is traced against this historical background. The (in)famous history of historical Jesus-research necessitates a conscious choice of method. The traditional focus on sayings material and criteria of authenticity is modified; narrative traditions with implicit purity issues are appealed to, and extra-canonical traditions are included. The main areas examined are the most important "fathers" of impurity: "leprosy" (skin diseases), genital discharges and corpse-contamination. Jesus is found to have acted in ways easily understood as indifference to these types of impurity. His behaviour is shown on several points to clash with current purity halakhah and dominant expansionist ideals. In an attempt to interpret his actions within the Jewish context and culture of the Second Temple period, three explanatory models are provided. Jesus’ attitude is seen as part of a moral trajectory in Judaism. It is understood as a response to a regional, Galilean dilemma. It is viewed in a power perspective as an expression of Jesus’ eschatological struggle against demonic evil. The result is that Jesus may be understood as operating within the purity paradigm of his time, yet pushing it to the breaking point, at least in the eyes of some. Such a reconstruction makes subsequent developments intelligible, in which various Christian currents drew conflicting conclusions. The function and effect of purity laws change with time, however. While they are irrelevant to most modern people, those looking to Jesus’ behaviour for some sort of guidance may find contemporary analogies.
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| 8. |
- Kempen, Thomas G. H., 1988-
(författare)
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Medication reviews by clinical pharmacists in older hospitalised patients : Implementation, performance and effects
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background Inappropriate use of medications is a leading cause of avoidable harm in health care. Medication reviews by clinical pharmacists improve medication use, but evidence on hard clinical outcomes in older hospitalised patients is scarce and implementation in practice is challenging. The aim of this thesis was to study the implementation, performance and effects of medication reviews by clinical pharmacists in older hospitalised patients.Methods A case study explored the factors involved in the implementation and sustainability of medication reviews by clinical pharmacists in Region Uppsala, Sweden. A pragmatic multicentre cluster-randomised crossover trial (MedBridge) was conducted to study the effects of hospital-based comprehensive medication reviews (CMRs) including post-discharge follow-ups on older patients’ healthcare utilisation, compared with only hospital-based reviews and usual care. The primary outcome measure was the incidence of unplanned hospital visits within 12 months. A process evaluation was conducted alongside the trial, for which different methods were applied: semi-structured interviews with patients and healthcare professionals, intervention fidelity assessment and process outcomes assessment. A practical tool to identify medication-related hospital admissions, one of the trial’s secondary outcomes, was developed and validated.Results Multiple factors involved in the implementation and sustainability of medication reviews by clinical pharmacists were identified. Examples of facilitating factors were a national focus on quality of care for the elderly and clinical pharmacy education. In total, 2637 participants (median age 81 years) were included in the MedBridge trial. The primary outcome measure did not differ between the treatment groups. Analysis of the interviews with patients and healthcare professionals resulted in seven and six themes, respectively, that were related to the performance of the trial’s interventions. A recurrent theme was the unclear role and responsibilities of the ward-based pharmacist. The intervention fidelity was high during hospital admission and lower surrounding discharge. In 77% of the intervention patients, at least one medication discrepancy or drug-related problem was solved. The developed tool, AT-HARM10, was deemed valid for use by pharmacy students to identify medication-related admissions in older patients.Conclusions This thesis suggests that, despite a high percentage of patients with medication discrepancies or drug-related problems being solved, hospital-based CMRs with and without post-discharge follow-ups, as conducted in the MedBridge trial, do not decrease the incidence of unplanned hospital visits in older patients. Future research and clinical initiatives may benefit from addressing the factors related to the implementation and performance of medication reviews that were identified in this thesis.
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| 9. |
- Mejtoft, Thomas, 1976-
(författare)
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Institutional arrangements and competitive posture : effects of company structures in the commercial printing industry
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The research objective of this dissertation is to investigate the impact of institutional arrangements, with respect to vertical integration and cooperation, on competitive advantages within the commercial printing industry, with specific focus on digital printing. This dissertation comprises six research papers, based on four qualitative case studies and a quantitative survey study, all carried out in Sweden in the years 2004-2008.The results show that vertical integration is a way to achieve competitive advantages in the commercial printing industry and is a widely used strategy in Sweden. Being able to contract full service companies is appreciated by customers to printing houses, especially direct customers, due to their need for a supplier of complete solutions for printed matters. Consequently, a vertically integrated company can provide value added services which makes it possible for customers to minimize their organization regarding production and purchasing of printed matters. Other reasons for vertical integration are the need to ensure fast deliveries to customers and having a steady supply of appropriate jobs. Despite the believed strategic importance by the industry, the results show that the level of vertical integration has no significant impact on profitability. Vertical integration is strategically important for digital printing houses in order to develop their business because digital printing allows for fast deliveries, on-demand printing and variable data printing. Despite the commoditization of printed matter, the findings indicate that the industry, in general, focuses on providing a high service level even though it means having to set higher prices. Furthermore, the results point toward that this strategic positioning is beneficial for digital printing houses because they experience a lower degree of competition and a lower price pressure.Vertical integration can, however create inflexibility due to ownership and employment. The findings suggest that cooperation can be used to achieve fast access to valuable resources, such as production equipment and knowledge, and, hence, increase printing houses’ resource flexibility. Even though internal control of resources is regarded as important to be able to satisfy customers’ needs and produce customers’ orders on time, cooperation with partners can create similar strategic effects. Furthermore, cooperation can give cost and flexibility advantages compared to vertical integration by reducing internal need for production capacity and allowing access to complementary resources. Nevertheless, it is common to combine vertical integration with cooperation to create competitive advantages and make a company more flexible and dynamic toward market changes.
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| 10. |
- Monroy, Maria Carlota, 1954-
(författare)
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Ecology and Control of Triatomine (Hemiptera: Reduviidae) Vectors of Chagas Disease in Guatemala, Central America
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis analyses several factors affecting the control of triatomines in Guatemala. There are three synantropic triatomines in Guatemala, i.e., Rhodnius prolixus, Triatoma dimidiata and T. nitida. Their distibution is mainly at an altitude between 800 and 1500 m a.s.l. R. prolixus and T. nitida have localized but scaterred distibution while T. dimidiata is present in 21 of the 22 departments in the country. Several investigations have shown that R. prolixus could be relatively easily eradicated while T. dimidiata may be more difficult to control, since it is present in domestic, peridomestic and sylvatic environments showing high diversity and a variety of epidemiological characteristics. Based on the incidence of Trypanosma cruzi infection in humans in the distributional areas of the triatomines, R. prolixus appear to be a more competent vector than T. dimidiata. This is despite the fact that these vectors have similar infection rates. Inside houses, R. prolixus and T. dimidiata and in artificial environments, T. ryckmani and T. dimidiata, preferred the northern side of the walls. Therefore, selective application of insecticides should focus on walls and furniture located in the northern part of the house. House improvements reduced the infestation of triatomines, and could be used as a complement to insecticidal spraying. Although T. dimidiata is not an efficient vector its wide distribution, versatility in occupying different habitats and capacity to disperse render this species difficult to control in Central America. Thus, only few months after insecticidal spraying T. dimidiata had reinfested the domestic environments. Morphometic methodology and genetic markers have been developed to differentiate within-species populations of T. dimidiata and T. nitida. Studies on the migration patterns of sylvatic T. dimidiata and T. ryckmani have been performed in order to clarify the colonization patterns. The adults migrate, in particular, in the dry part of the year. This finding may be of help in attempts to control T. dimidiata.
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