| 1. |
- Hadin, Åsa
(författare)
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From waste problem to renewable energy resource : exploring horse manure as feedstock for anaerobic digestion
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A sustainable energy system requires, according to energy policies, reduced emissions of greenhouse gases, increased ratio of renewable sources of energy and more efficient use of energy. Horse manure could be regarded as waste, but also as a resource for renewable energy and plant nutrients. This thesis explores the potential of horse manure as a renewable energy source, and its possibilities to support and contribute to energy and environmental objectives. To do this, data was collected from literature, simulations, study visits and interviews.A number of horse keeping activities were identified in the assessment of horse manure as a feedstock for energy and as a plant resource: feeding, indoor housing, outdoor keeping, manure storage, fertilizing and transport, all with effect on amount and content of horse manure. Results indicated that choice and amount of bedding are important for both energy performance and plant nutrient content in the biofertilizer. Operational conditions such as long hydraulic retention time and high temperature had less impact for horse manure as a biogas feedstock. Anaerobic digestion resulted in the lowest global warming potential compared to incineration and composting, while large-scale incineration reduced primary energy demand, acidification potential and eutrophication potential. In a subsequent simulation, anaerobic digestion had lower potential environmental impact than unmanaged composting, regarding all chosen environmental impact categories in the study. Experiences from energy companies suggest that horse manure can be used in small quantities in co-incineration, with suitable incineration technology, but odor was mentioned as a problem. Farm-scale incineration required continuous maintenance and monitoring and mixing with pellets. As a feedstock for anaerobic digestion horse manure was regarded as suitable for plug-flow processes while stirred processes experienced more technical problems leading to increased cost for plants. With adaption of horse manure to the energy recovery technology to be used, and adaption at energy conversion plants to homogenous materials, this not yet fully utilized bioenergy resource has potential to contribute with renewable energy to the energy system, and thereby also reduce environmental impact from horse manure treatment
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| 2. |
- Wallhagen, Marita
(författare)
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Environmental Assessment Tools for Neighbourhoods and Buildings in relation to Environment, Architecture, and Architects
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis explores Neighbourhood and Building Environmental Assessment Tools’ (NBEATs’) function as assessment tools and decision support, and their relation to environment, architecture and architects. This is done by analysing, testing, and discussing a number of NBEATs (LEED-NC, Code for Sustainable Homes, EcoEffect, LEED-ND, BREEAM-C, and ENSLIC-tool), their manuals and use. Moreover, professionals’ (architects’) self-rated opinions regarding use and knowledge of NBEATs and environmental aspects are surveyed.Similarities and differences in NBEATs are found regarding: content, structure, weighting and indicators used. Indicators distinguished as procedure, performance and feature are used to varying extents to assess social, environmental and technical aspects. NBEATs relation to environmental sustainability has limitations due to: non-transparency, tradable indicators, relative measures, low criteria levels, limited life cycle perspective, and exclusion of relevant environmental aspects, such as embedded toxic substances, nutrient cycles, land use change, and ecosystem services. Ratings and architecture are influenced by NBEATs in varying ways. Higher criteria levels would probably increase their impact on architecture. Thus more research regarding NBEATs and links to architectural design, theory and practice is welcomed.There is limited use of NBEATs as decision support in early design phases such as in architectural competitions. Architects rate the importance of environmental aspects high, but few rate their skill in handling environmental aspects high. This calls for increasing knowledge and know-how of environmental strategies and solutions among architects and adaptation of NBEATs to early design processes. The values NBEATs reflect and the values we want them to create is also important. To support ‘environmental’ architecture, an increased socio-eco-technological system perspective is put forward, and other measures besides NBEATs are needed.
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| 3. |
- Eriksson, Gabriella
(författare)
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On Physical Relations in Driving: Judgements, Cognition and Perception
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Drivers need to make judgements of physical relationships related to driving speed, such as mean speed, risks, travel time and fuel consumption, in order to make optimal choices of vehicle speed. This is also the case for the general public, politicians and other stakeholders who are engaged in traffic issues. This thesis investigates how drivers’ judgements of travel time (Study I and II), fuel consumption (Study III) and mean speed (Study IV) relate to actual physical measures.A cognitive time-saving bias has been found in judgements of travel time. The time saving bias implies that people overestimate the time saved when increasing speed from a high speed and underestimate the time saved when increasing speed from a low speed. Previous studies have mainly investigated the bias from a cognitive perspective in questionnaires. In Study I the bias was shown to be present when participants were engaged in a driving simulator task where participants primarily rely on perceptual cues. Study II showed that intuitive time saving judgements can be debiased by presenting drivers with an alternative speedometer that indicate the inverted speed in minutes per kilometre.In Study III, judgements of fuel consumption at increasing and decreasing speeds were examined, and the results showed systematic deviations from correct measures. In particular, professional truck drivers underestimated the fuel saving effect of a decrease in speed. Study IV showed that subjective mean speed judgements differed from objective mean speeds and could predict route choice better than objective mean speeds. The results indicate that biases in these judgements are robust and that they predict behaviour.The thesis concludes that judgements of mean speeds, time savings and fuel consumption systematically deviate from physical measures. The results have implications for predicting travel behaviour and the design of driver feedback systems.
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| 4. |
- Eriksson, Ola, 1979-
(författare)
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Numerical Computations of Wakes Behind Wind Farms : A tool to study Farm to Farm interaction
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- More and larger wind farms are planned offshore. As the most suitable sites to build are limited these new wind farms will be constructed near to each other in so called wind farm clusters. Behind the wind turbines in these farms there is a disrupted flow of air called a wake that is characterized by reduced wind speed and increased turbulence. These individual turbine wakes combine to form a farm wake that can travel long distances. In wind farm clusters farm to farm interaction will occur, i.e. the long distance wake from one wind farm will impact the wind conditions for other farms in the surrounding area.This thesis contains numerical studies of these long distance wakes. In these studies Large Eddy Simulations (LES) using an Actuator Disc method (ACD) are used. A prescribed boundary layer is used where the wind shear is introduced using body forces. The turbulence, based on the Mann model, is introduced as fluctuating body forces upstream of the farm. A neutral atmosphere is assumed. The applied method has earlier been used for studies of wake effects inside farms but not for the longer distances needed for the study of farm to farm interaction. Parameter studies are setup to analyze how to best use the model for the study of long distance wakes with regards to 1) numerical and physical parameters in the model, 2) the extension of the domain and turbulence as well as the characteristics of the flow far downstream and 3) the downstream development of turbulence with different combinations of wind shear and turbulence level.Using an initial simulation setup a wind farm was studied and preliminary results were obtained. These results were subsequently improved upon by applying the simulation setup adjustments indicated in the parameter studies. A comparison with a mesoscale model was also done. The mesoscale model was shown to be relevant for studies of long distance wakes in another study comparing LES and WRF. Finally an idealized farm to farm interaction case was studied with focus on the impact of including the Coriolis force in the simulations.Combining LES with a mesoscale model is of interest to study further.
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| 5. |
- Gustafsson, Kristin, 1976-
(författare)
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Hip and Knee Osteoarthritis : Who Are the Patients Referred to First-Line Intervention and What Happens to Them?
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: First-line intervention to address osteoarthritis (OA) should include patient education, exercise therapy, and weight control if needed. Replacement surgery may be appropriate for patients who do not receive sufficient relief from non-surgical interventions. However, predicting the course of OA can be challenging. Some patients experience stable symptoms over time, while others may have a rapid increase in pain and functional impairment. This thesis aims to improve understanding of which patients are referred to first-line intervention for hip and knee OA and to identify factors that affect long-term outcomes in these patients.Methods: The thesis includes studies of patients with hip and knee OA referred to a standardized first-line intervention programme. Study A (papers I, II, IV, V) is a register-based observational study that uses the Swedish Osteoarthritis Register (SOAR) to identify an OA population (n = 72 069). Data from the SOAR was merged with data from the Swedish Arthroplasty Register, Statistics Sweden and the National Board of Health and Welfare. The study also includes a matched reference cohort (n = 216 207) from the general Swedish population for comparison. Papers I and II compare socioeconomic status (SES) and comorbidities of the OA population in the SOAR with the reference cohort. Study B (paper III) is a qualitative study involving 16 patients with hip and knee OA who expressed a desire for surgery at referral to first-line intervention. The study includes interviews regarding the patients’ perspectives on healthcare and self-management of OA. Paper IV examines the time to replacement surgery and prognostic factors for surgery in the OA population. Paper V identifies factors associated with poorer patient-reported outcomes 1 year after hip replacement surgery.Results: The OA population had higher SES and higher odds of having comorbidities than the reference cohort. The differences in comorbidities were greater in younger individuals and those with knee OA. Patients who expressed a desire for surgery before participating in first-line intervention described their perspectives on healthcare and self-management as a multifaceted picture of needs, expectations, and individual choices. Findings range from a passive approach towards managing the OA, described as a lack of control, a sense of being left alone by healthcare, having doubts and mistrusting the care provided, to a more active attitude manifested as a will to take control over the OA, instead of the OA taking control over the patient’s life. Of the patients registered in the SOAR, 46% with hip OA and 20% with knee OA were estimated to progress to replacement surgery within 5 years. The strongest prognostic factors were expressing a desire for surgery and having more severe OA symptoms. In addition, higher SES and the presence of comorbidities had an impact on the risk of progression to surgery. Among those who had undergone a hip replacement, 5%–11% showed poor patient-reported outcomes regarding pain, health-related quality of life, and satisfaction 1 year after surgery. Factors associated with poor outcomes were being older, classified as Charnley C (musculoskeletal comorbidities), or having several comorbidities, particularly depression.Conclusions: Higher SES in the OA population referred to first-line intervention than in the general population indicates that OA care in Sweden may not be equal. The higher prevalence of comorbidities in the OA population suggests that OA care should include improving overall health. Furthermore, first-line OA intervention should be tailored to each patient’s perspectives to achieve the lifestyle changes that the interventions strive to accomplish, especially in patients expressing a desire for surgery at referral. Patients with hip and knee OA differ in their progression to surgery. Those with hip OA tend to progress faster and undergo replacement surgery more often than those with knee OA. Expressing a desire for surgery and having severe OA symptoms are prognostic factors, but other non-OA-related factors play a significant role. However, a large proportion of patients with OA do not require surgery within 5 years after referral to first-line intervention, especially those with knee OA. Identifying depression at the stage of referral to first-line OA intervention would allow increased time to optimize treatments and may help improve patient-reported outcomes after surgery.
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| 6. |
- Leifler, Ola
(författare)
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Affordances and Constraints of Intelligent Decision Support for Military Command and Control : Three Case Studies of Support Systems
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Researchers in military command and control (C2) have for several decades sought to help commanders by introducing automated, intelligent decision support systems. These systems are still not widely used, however, and some researchers argue that this may be due to those problems that are inherent in the relationship between the affordances of technology and the requirements by the specific contexts of work in military C2. In this thesis, we study some specific properties of three support techniques for analyzing and automating aspects of C2 scenarios that are relevant for the contexts of work in which they can be used.The research questions we address concern (1) which affordances and constraints of these technologies are of most relevance to C2, and (2) how these affordances and limitations can be managed to improve the utility of intelligent decision support systems in C2. The thesis comprises three case studies of C2 scenarios where intelligent support systems have been devised for each scenario.The first study considered two military planning scenarios: planning for medical evacuations and similar tactical operations. In the study, we argue that the plan production capabilities of automated planners may be of less use than their constraint management facilities. ComPlan, which was the main technical system studied in the first case study, consisted of a highly configurable, collaborative, constraint-management framework for planning in which constraints could be used either to enforce relationships or notify users of their validity during planning. As a partial result of the first study, we proposed three tentative design criteria for intelligent decision support: transparency, graceful regulation and event-based feedback.The second study was of information management during planning at the operational level, where we used a C2 training scenario from the Swedish Armed Forces and the documents produced during the scenario as a basis for studying properties of Semantic Desktops as intelligent decision support. In the study, we argue that (1) due to the simultaneous use of both documents and specialized systems, it is imperative that commanders can manage information from heterogeneous sources consistently, and (2) in the context of a structurally rich domain such as C2, documents can contain enough information about domain-specific concepts that occur in several applications to allow them to be automatically extracted from documents and managed in a unified manner. As a result of our second study, we present a model for extending a general semantic desktop ontology with domain-specific concepts and mechanisms for extracting and managing semantic objects from plan documents. Our model adheres to the design criteria from the first case study.The third study investigated machine learning techniques in general and text clustering in particular, to support researchers who study team behavior and performance in C2. In this study, we used material from several C2 scenarios which had been studied previously. We interviewed the participating researchers about their work profiles, evaluated machine learning approaches for the purpose of supporting their work and devised a support system based on the results of our evaluations. In the study, we report on empirical results regarding the precision possible to achieve when automatically classifying messages in C2 workflows and present some ramifications of these results on the design of support tools for communication analysis. Finally, we report how the prototype support system for clustering messages in C2 communications was conceived by the users, the utility of the design criteria from case study 1 when applied to communication analysis, and the possibilities for using text clustering as a concrete support tool in communication analysis.In conclusion, we discuss how the affordances and constraints of intelligent decision support systems for C2 relate to our design criteria, and how the characteristics of each work situation demand new adaptations of the way in which intelligent support systems are used.
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| 7. |
- Lindkvist, Emma, 1984-
(författare)
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System studies of biogas production : comparisons and performance
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Biogas has the potential to be part of the transition towards a more sustainable energy system. Biogas is a renewable energy source and can play an important role in modern waste management systems. Biogas production can also help recirculate nutrients back to farmland. Besides all this, biogas is a locally produced energy source with the potential to increase global resource efficiency, since it can lead to more value and less waste, as well as decreased negative environmental effects. However, biogas production systems are complex, including different substrates, different applications for biogas and digestate, and different technology solutions for digestion, pre-treatment and for upgrading the raw gas. To increase the development of biogas production systems, knowledge sharing is a key factor. To increase this knowledge sharing, comprehensible analysis and comparisons of biogas production systems are necessary. Thus, studies are needed to verify the resource efficiency of biogas production systems from different perspectives.The aim of this thesis is to perform a systems analysis of biogas production systems and to explore how to analyse and compare biogas production systems. An additional aim is to study biogas production systems from a systems perspective, with a focus on environment, energy and economy. Studying biogas production systems from different system levels, as well as from different approaches, is beneficial because it results in deeper knowledge of biogas systems and greater opportunities to identify synergies.Systems studies of biogas are important, since biogas systems are often complex and integrated with other systems. In this thesis, biogas systems analyses are performed at different levels. In the widest system study, classifications of different biogas plants are analysed and classifications in different European countries are compared, with the prospect of paving the way for a new common classification for biogas plants in Europe. Today, classifications vary between countries, and hence comparisons of plants in different countries are difficult. In the narrowest system study, a new methodology for analysing energy demand at different biogas production plants has been developed. The aim was to develop a methodology that is applicable for all kinds of biogas plants with energy inputs. The methodology describes the process of analysing energy demand and allocating energy to sub-processes and unit processes.Further, an approach for assessing the resource efficiency of different treatment options for organic waste was designed. The approach includes environmental, economic and energy perspectives, and was applied to five different regions with several food manufacturing companies. A study of treatment options for organic waste from a single food company was also conducted. The results showed that biogas production is a resource-efficient way to treat waste from the food industry. The approach enables a wider analysis of biogas systems, and the results from the applications show the complexity of assessing resource efficiency. It is also shown that it is important to understand that the resource efficiency of a system is always in relation to the substituted system.In this thesis, three different approaches to analysing biogas production systems are presented: categorization, resource efficiency analysis and energy demand analysis. These approaches all contribute to the understanding of biogas systems and can help, in different ways, to increase knowledge about biogas systems in the world. If knowledge about different biogas systems can be easily disseminated, more of the unused potential of biogas production may be realized, and hence more fossil fuels can be replaced within the energy system.
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| 8. |
- Eriksson, Ola, 1967-
(författare)
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Characterisation and modelling of radio-frequency lesioning in functional neurosurgery
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis focuses on the characterisation and modelling of the radio frequency (RF) lesioning with emphasis on size estimation in functional neurosurgery. A computer-assisted video system has been set up for standardised test and documentation of protein clots generated by RF-lesioning electrodes in an albumin solution. A standardised test is essential in comparing assessed results of the size and shape of protein clots generated using different parameters. This is beneficial to both the manufacturer oflesioning electrodes as well as the surgeon.In an animal study, performed analogously to thalamotomy in man, the correlation in size between in vitro protein clots and in vivo lesions has been investigated. The result shows a high correlation between protein clots and lesions observed on MR images; and lesions observed on MR images and corresponding coagulated tissue in histological sectionings. This actualises the value of presurgical electrode tests to validate the electrode function and lesion size in vitro.A finite element model has been set-up in order to facilitate studies of the growth and the temperature distribution during the lesioning process. Of the utmost importance is the finding of a difference in temperature between maximum temperature, located outside the electrode, compared to the intra-electrode (thermocouple) temperature.A method for real time monitoring of lesion growth and estimation of lesion size utilising static and/or Doppler broadened laser light is proposed. Implemented in a surgical-assist system, this could give valuable guidance to the surgeon as to whether the desired lesion size is obtained or not and keep the destruction precise, but to a minimum.
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| 9. |
- Gustafsson, Kristin, 1976-, et al.
(författare)
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What Factors Identified in Initial Osteoarthritis Management Are Associated With Poor Patient-reported Outcomes After THA? : A Register-based Study
- 2023
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Ingår i: Clinical Orthopaedics and Related Research. - : LIPPINCOTT WILLIAMS & WILKINS. - 0009-921X .- 1528-1132. ; 481:9, s. 1732-1742
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Some patients report long-term pain or no improvement in health-related quality of life (HRQoL) or are dissatisfied after THA. However, factors associated with these poorer patient-reported outcomes after surgery are inconsistent and have typically been studied in the late phase of hip osteoarthritis (OA) among patients already eligible for surgery. Earlier identification of risk factors would provide time to address modifiable factors, helping to improve patients' pain, HRQoL, and satisfaction after surgery and reduce the burden on orthopaedic clinics by referring patients who are better prepared for surgery.QUESTIONS/PURPOSES: We analyzed data from patients with hip OA referred to a first-line OA intervention program in primary healthcare at a stage when they had not been referred for THA, and asked: (1) What percentage of patients who proceed to THA report lack of improvement in pain, lack of improvement in HRQoL as measured by the EQ-5D, or are not satisfied with surgery 1 year after THA? (2) What associations exist between baseline factors at referral to this first-line OA intervention program and these poorer patient-reported outcomes 1 year after THA?METHODS: We included 3411 patients with hip OA (mean age 67 ± 9 years, 63% [2160 of 3411] women) who had been referred for first-line OA interventions between 2008 and 2015 and subsequently underwent THA for OA. All patients were initially identified through the Swedish Osteoarthritis Register, which follows and evaluates patients in a standardized national first-line OA intervention program. Then, we identified those who were also registered in the Swedish Arthroplasty Register with a THA during the study period. We included only those with complete patient-reported outcome measures for pain, HRQoL, and satisfaction preoperatively and 1-year postoperatively, representing 78% (3411 of 4368) of patients, who had the same baseline characteristics as nonrespondents. Multiple logistic regression was used to assess the associations between 14 baseline factors and the aforementioned patient-reported outcomes of pain, HRQoL, and satisfaction 1 year after THA, adjusted for all included factors.RESULTS: Five percent (156 of 3411) of the study population lacked improvement in pain, 11% (385 of 3411) reported no improvement in HRQoL, and 10% (339 of 3411) reported they were not satisfied with surgery 1 year after THA. Charnley Class C (multiple-joint OA or another condition that affects the ability to walk) was associated with all outcomes: lack of improvement in pain (OR 1.84 [95% CI 1.24 to 2.71]; p = 0.002), lack of improvement in HRQoL (OR 1.83 [95% CI 1.42 to 2.36]; p < 0.001), and not being satisfied (OR 1.40 [95% CI 1.07 to 1.82]; p = 0.01). Older age was associated with a lack of improvement in pain (OR per year 1.03 [95% CI 1.01 to 1.05]; p = 0.02), lack of improvement in HRQoL (OR per year 1.04 [95% CI 1.03 to 1.06]; p < 0.001), and not being satisfied (OR per year 1.03 [95% CI 1.01 to 1.05]; p < 0.001). Depression was associated with a lack of improvement in pain (OR 1.54 [95% CI 1.00 to 2.35]; p = 0.050) and with not being satisfied (OR 1.50 [95% CI 1.11 to 2.04]; p = 0.01) but not with a lack of improvement in HRQoL (OR 1.04 [95% CI 0.76 to 1.43]; p = 0.79). Having four or more comorbidities was associated with a lack of improvement in HRQoL (OR 2.08 [95% CI 1.39 to 3.10]; p < 0.001) but not with a lack of improvement in pain and not being satisfied.CONCLUSION: The results of this study showed that older age, Charley Class C, and depression in patients with first-line OA interventions were risk factors associated with poorer outcomes regarding pain, HRQoL, and satisfaction after THA. Screening patients with hip OA for depression early in the disease course would provide increased time to optimize treatments and may contribute to better patient-reported pain, HRQoL, and satisfaction after future THA. Further research should focus on identifying the optimal time for surgery in patients with depression, as well as what targeted interventions for depression can improve outcome of surgery in these patients.LEVEL OF EVIDENCE: Level III, therapeutic study.
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| 10. |
- Lidman, Linda, 1978-
(författare)
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Employee-driven innovation in the public sector : At the intersection of innovation support and workplace conditions
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The overall aim of this thesis is to contribute knowledge about employee-driven innovation (EDI), with a particular focus on conditions in the workplace when innovation support is introduced in municipal contexts. The thesis is based on 23 qualitative interviews with managers, employees, and innovation coaches from three municipal sites in Sweden where innovation support has been implemented. The four included studies examine how innovation support is set up, what role first-line managers play, what drives employees to engage in EDI, and the outcomes of innovation work in the studied cases.The thesis’ results show how innovation support was set up as parallel structures operating independently from regular municipal operations, which made it difficult for employees and managers to connect and integrate innovation work with everyday work. Furthermore, the results show how the studied municipalities did not define clear objectives for working with innovation, which in turn resulted in a multitude of inextricably linked negative effects for the innovation support operations, the managers, the employees, and the outcome of the innovation work. In addition, the study results demonstrate the importance of providing rich environments for learning and innovation in the workplace, to consider and support employee engagement in public sector innovation and to support the entire innovation process, including the implementation phase. The first conclusion drawn is that employee-driven innovation work happens at the intersection of innovation support and current workplace conditions. This implies that support measures need to be integrated into employees’ everyday work to create favourable conditions for EDI. The second conclusion is that it is imperative for municipal organisations intending to support EDI to define objectives for working with innovation and to anchor and communicate these objectives throughout the organisation.
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