| 1. |
- Thollander, Patrik, 1976-
(författare)
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Towards Increased Energy Efficiency in Swedish Industry : Barriers, Driving Forces & Policies
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Industrial energy efficiency is one of the most important means of reducing the threat of increased global warming. A higheruse of electricity than their European competitors, together with increased energy costs due to increasing energy prices in Swedish industry have negative impacts on results and competitiveness. Of great importance are thus different means which promote energy efficiency such as industrial energy policy instruments. However, cost-effective energy efficiency measuresare not always undertaken. In order to formulate and adopt accurate industrial energy end-use polices, it is thus of importanceto identify the barriers that inhibit the implementation of cost-effective energy efficiency measures. It is also of importance to identify the factors which promote the implementation. The aim of this thesis is to analyze industrial energy systems andmore specifically study factors that promote or inhibit energy end-use efficiency in Swedish industrial companies.Results from this thesis show that the implementation of technical energy efficiency measures is a major means for both energy-intensive and non-energy-intensive Swedish companies to overcome the threat of rising energy prices, for example for electricity. While energy efficiency measures in the non-energy-intensive industry are related mainly to support processes, measures in the studied energy-intensive Swedish foundry industry are related to both support and production processes.In the various case studies of barriers and driving forces, the most significant barriers to energy efficiency - with largevariations for some of the barriers among the studied cases - were found to be: technical risk such as risk of productiondisruptions; lack of time or other priorities; lack of access to capital; cost of production disruption/hassle/inconvenience; other priorities for capital investments; technology considered inappropriate at the site; difficulty/cost of obtaininginformation about the energy use of purchased equipment; and lack of budget funding. The largest driving forces, apart fromcost reductions resulting from lowered energy use, were found to be the existence of a long-term energy strategy and peoplewith real ambition. These driving forces did not, unlike the results of barriers to energy efficiency, vary widely across thestudied sectors.Investment decision support such as optimization has shown to add more information for larger capital-intensive investmentsin energy-intensive industrial SMEs. The thesis also showed that energy audits are an effective means, in terms of publicmoney spent per kWh saved, of providing the industry with information on potential energy efficiency measures.Based on the results presented in this thesis, a policy approach towards non-energy-intensive companies and industrial SMEsshould primarily include providing energy audits free of charge and involve the local authority energy consultants.
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| 2. |
- Clark, DW, et al.
(författare)
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Associations of autozygosity with a broad range of human phenotypes
- 2019
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1, s. 4957-
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Tidskriftsartikel (refereegranskat)abstract
- In many species, the offspring of related parents suffer reduced reproductive success, a phenomenon known as inbreeding depression. In humans, the importance of this effect has remained unclear, partly because reproduction between close relatives is both rare and frequently associated with confounding social factors. Here, using genomic inbreeding coefficients (FROH) for >1.4 million individuals, we show that FROH is significantly associated (p < 0.0005) with apparently deleterious changes in 32 out of 100 traits analysed. These changes are associated with runs of homozygosity (ROH), but not with common variant homozygosity, suggesting that genetic variants associated with inbreeding depression are predominantly rare. The effect on fertility is striking: FROH equivalent to the offspring of first cousins is associated with a 55% decrease [95% CI 44–66%] in the odds of having children. Finally, the effects of FROH are confirmed within full-sibling pairs, where the variation in FROH is independent of all environmental confounding.
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| 3. |
- Jonsson, Joakim, 1984-
(författare)
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Integration of MRI into the radiotherapy workflow
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The modern day radiotherapy treatments are almost exclusively based on computed tomography (CT) images. The CT images are acquired using x-rays, and therefore reflect the radiation interaction properties of the material. This information is used to perform accurate dose calculation by the treatment planning system, and the data is also well suited for creating digitally reconstructed radiographs for comparing patient set up at the treatment machine where x-ray images are routinely acquired for this purpose.The magnetic resonance (MR) scanner has many attractive features for radiotherapy purposes. The soft tissue contrast as compared to CT is far superior, and it is possible to vary the sequences in order to visualize different anatomical and physiological properties of an organ. Both of these properties may contribute to an increase in accuracy of radiotherapy treatment.Using the MR images by themselves for treatment planning is, however, problematic. MR data reflects the magnetic properties of protons, and thus have no connection to the radiointeraction properties of the material. MRI also has inherent difficulty in imaging bone, which will appear in images as areas of no signal similar to air. This makes both dose calculation and patient positioning at the treatment machine troublesome.There are several clinics that use MR images together with CT images to perform treatment planning. The images are registered to a common coordinate system, a process often described as image fusion. In these cases, the MR images are primarily used for target definition and the CT images are used for dose calculations. This method is now not ideal, however, since the image fusion may introduce systematic uncertainties into the treatment due to the fact that the tumor is often able to move relatively freely with respect to the patients’ bony anatomy and outer contour, especially when the image registration algorithms take the entire patient anatomy in the volume of interest into account.The work presented in the thesis “Integration of MRI into the radiotherapy workflow” aim towards investigating the possibilities of workflows based entirely on MRI without using image registration, as well as workflows using image registration methods that are better suited for targets that can move with respect to surrounding bony anatomy, such as the prostate.
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| 4. |
- Kakkar, Aditya, 1989-
(författare)
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Frequency Noise in Coherent Optical Systems: Impact and Mitigation Methods
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The increase in capacity demand along with the advancement in digital signal processing (DSP) have recently revived the interest in coherent optical communications and led to its commercialization. However, design and development of robust DSP algorithms for example for carrier phase recovery (CPR) becomes complex as we opt for high order modulation formats such as 16QAM and beyond. Further, electrical-domain dispersion compensation (EDC), while providing many advantages, makes the system more susceptible to laser frequency noise (FN). For instance, in coherent optical links with post-reception EDC, while the transmitter frequency noise causes only phase impairment, the local oscillator (LO) FN in these systems results in a noise enhancement in both amplitude and phase. This noise is commonly known as equalization enhanced phase noise (EEPN). It results in asymmetric requirements for transmitter laser and LO laser. Further, the system design in the presence of lasers with non-white frequency noise becomes increasingly challenging for increased capacity-distance product.The main contributions of this thesis are, firstly, an experimentally validated theory of coherent optical links with lasers having general non-white frequency noise spectrum and corresponding system/laser design criteria and mitigation technique. Secondly, low complexity and high phase noise tolerant CPR for high order modulation formats.The general theory propounded in this thesis elucidates the origin of the laser frequency noise induced noise enhancement in coherent optical links with different DSP configurations. The thesis establishes the existence of multiple frequency noise regimes and shows that each regime results in different set of impairments. The influence of the impairments due to some regimes can ideally be reduced by optimizing the corresponding mitigation algorithms, while other regimes cause irretrievable impairments. Experimentally validated theoretical boundaries of these regimes and corresponding criteria applicable to system/laser design are provided. Further, an EEPN mitigation method and its two possible implementations are proposed and discussed.The thesis also demonstrates an intrinsic limitation of the conventional Blind Phase Search (BPS) algorithm due to angular quantization and provides methods to overcome it. Finally, this thesis proposes and demonstrates single stage and multi-stage carrier phase recovery algorithms for compensation of phase impairments due to the two lasers for higher order circular and square modulations. The proposed methods outperform the state of art algorithms both in performance and in complexity.
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| 5. |
- Karlsson, Olof Magnus, 1972-
(författare)
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Predicting Ecosystem Response from Pollution in Baltic Archipelago areas using Mass-balance Modelling
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Baltic archipelago areas have high nature values despite being polluted from various antrophogenic activities within the Baltic Sea catchment area and from long-range transport of airborne substances. The discovery of environmental problems in the Baltic Sea in the 1960s led to countermeasures that gradually gave results in reducing the toxic pollution, e.g. from PCBs. Today, much of the environmental management is focused on reducing the effects of eutrophication. There is a demand from society on science to develop strategies that can direct remedial actions so that the cost-effectiveness is maximised. This work focuses on how mass-balance models can be used to understand how coastal ecosystems are controlled by abiotic processes and to predict the response to changes in loading of different substances. Advection, sedimentation and burial are examples of general transport processes that are regulated by morphometrical characteristics, e.g. size, form, effective fetch and topographical openness. This is why different coastal areas have different sensitivity to loading of pollutants. A comparison of six phosphorus and chlorophyll models of different complexity showed that the model performance was not improved with more state variables of total phosphorus (TP) than two water and two sediment compartments. Modelling chlorophyll as a separate state variable did not improve the results for individual values compared to a simple regression against total phosphorus in surface water. Field investigations of the phosphorus content in accumulation sediments along the coast of Svealand showed a distribution pattern that probably is related to differences in the redox status. The average content of mobile phosphorus was much higher than previously found in offshore Baltic sediments indicating that sediments may play an important role for the phosphorus turnover in Baltic archipelago areas. A one-year field study to measure the levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in water, sediments and fish during different seasons was carried out in Kallrigafjärden Bay. The collected data set was used to test a mass-balance model for PCCD/F-turnover. It was possible to reproduce the concentrations of different PCDD/F-congeners with high accuracy using a general model approach, including one water compartment and two sediment compartments, indicating that the applied model has the necessary qualifications for successful predictions of PCDD/F-turnover in Baltic coastal areas.
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| 6. |
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| 7. |
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| 8. |
- Rohdin, Patrik, 1977-
(författare)
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Energy efficiency and ventilation in Swedish industries barriers, simulation and control strategy
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The energy issue is presently in focus worldwide. This is not only due to increasing environmental concern regarding energy related emissions, but also due to the trend of increasing energy prices. Energy usage in the industrial sector in Sweden today represents about one third of the national energy use. A substantial part of that is related to support processes such as heating, ventilation and cooling systems. These systems are important as they are related both to energy cost and indoor climate management as well as to the health of the occupants.The purpose of this thesis is to reach a more comprehensive view on industrial energy efficiency and indoor environment issues related to industrial ventilation. This has been studied in three themes where the first part addresses barriers to energy efficiency in Swedish industries, the second theme discuss simulation as decision support, and the third studies the variable air volume system in industrial facilities.In the first theme three different studies were made: the first studies non-energy intensive companies in Oskarshamn in Sweden, the second studies the energy intensive foundry industry and the third study was part of an evaluation of a large energy efficiency program called Project Highland. These studies had several findings in common, such as the importance of a strategic view on the energy issue and the presence of a person with real ambition with power over investment decisions related to energy issues at the company. The studies also show that several information related barriers are important for decision makers at the studied companies. This shows that information related barriers are one reason in why energy efficient equipment is not implemented.In the second theme the use of simulation in the form of Computational Fluid Dynamics (CFD) and Building Energy Simulation (BES) are used as decision support for industrial ventilation related studies at two different industries, one foundry is investigated and one dairy. BES has mainly been used to simulate energy and power related parameters while CFD was used to give a detailed description of the indoor and product environment. Together these methods can be used to better evaluate the energy, indoor and product environment and thus enable the implementation of more efficient heating, ventilation and air-conditioning systems.In the third theme the use of Variable Air Volume (VAV) systems was evaluated, and was found to be an efficient way to reduce energy use at the studied sites. At the studied foundry the VAV system is predicted to reduce space heating and electricity use by fans by about 30%, and in the dairy case by about 60% for space heating and 20% for electricity.
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| 9. |
- Waldemarsson, Martin, 1983-
(författare)
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Planning production and supply chain in energy intensive process industries
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- To make a difference among the energy intensive process industries, this dissertation addresses production planning and supply chain planning problems related to industrial energy management issues. The energy issue is turning more and more important from different angles, involving price as well as environmental problems due to climate change leading to political pressure on all energy users. The process industry sector is one of the largest users of energy, and thus important to analyse. Process industries are also capital intensive and operate on large and expensive process equipment, making it imperative to plan their production well in order to reach preferable capacity utilisation. Therefore this dissertation strives to locate the most important energy management issues for the long term profitability of process industries, and investigates the symbiotic effects of including energy issues in production and supply chain planning.Three different studies at three case companies are carried out, analysed, and presented in five papers. The cases represent the process industry sectors: chemicals, pulp, and steel. Both qualitative case study methodologies as well as quantitative mathematical modelling and optimisation approaches have been practiced. The research questions are analysed from both an energy system and from a production process point of view, separately as well as combined. Energy is somewhat considered to be the main workforce for process industries and this dissertation exemplifies some of its most important dimensions in this context.Several prerequisites for putting energy management on the strategic agenda are located in a specialty chemical industry where the importance of introducing a strategic perspective on energy, the way energy is used, and the possibilities of increasing alternative revenue from utilising by- and/or co-products differently are pinpointed. Approaches for including energy issues in planning processes are also suggested in terms of a MILP model for the entire supply chain of a pulp company, including decisions on purchase and transportation of raw maerials, production allocation, energy mix, and distribution. Another example is presented based on the perspectives of economics of scale and lot sizing through economic order quantity principles in a steel company. By using real company data, energy smart approaches in planning and scheduling are developed with respect to the most important intersections between the production processes and their supporting energy system. The accumulated resource intensity and embedded energy could, and probably should, hence be more fairly reflected in the product price. The research finally shows some possible impact with including energy issues in a production and supply chain planning model. By planning differently, production prioritisations can be done, and it is not only possible without any large investments, but also prosperous with savings on both energy and money within reach.To conclude, planning of production and supply chain has either a direct or an indirect impact on the energy cost-effectiveness of a company. This dissertation argues that such impact also exists in its mutual form, and is very important when the energy issues are large enough, as they often are in the energy intensive process industry sector. Decision makers should thus beware of the short end of the stick that might be devastating in the long run, but also aware of all the possibilities that can bring success and prosperity when the future begins.
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| 10. |
- Birberg Thornberg, Ulrika
(författare)
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Fats in Mind : Effects of Omega-3 Fatty Acids on Cognition and Behaviour in Childhood
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis was to examine possible effects of omega-3 fatty acids on children’s cognition and behavior. Longitudinal as well as cross-sectional comparisons were made among children with typical development and children with ADHD /at risk developing ADHD.The specific purposes were to examine (1) breast-feeding in relation to cognition; (2) relation between long chain poly unsaturated fatty acids (LCPUFAs) in mothers breast-milk and children´s cognition; (3) effects of EPA supplementation on cognition and behavior in children with ADHD; (4) if LCPUFAs have differential effects on working memory, inhibition, problem-solving and theory of mind (ToM).The main conclusions were as follows; (1) duration of breast-feeding was positively correlated to children levels of intelligence (IQ); (2) LCPUFAs in breast-milk was related to children’s ToM and IQ, the quotient DHA/AA, together with length of breastfeeding and gestation week explained 76% of the variance of total IQ; (3) subtypes of children with ADHD responded to EPA supplementation with significant reductions in symptoms, but there were no effects in the whole group with ADHD; (4) ToM ability was related to LCPUFAs, but not to any other cognitive measures as working memory, inhibition and problem-solving.To conclude, these results indicate that fatty acid status in breast-milk at birth affect general cognitive function in children at 6.5 years of age, including ToM. Short-term intervention with omega-3 fatty acids does not affect cognition in children with ADHD, but improves clinical symptoms as assessed by means of teacher ratings. These results further indicate that hot executive function and social cognition may be an area of interest for future research.
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