| 1. |
- Antonsson, Stefan, 1979-
(författare)
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Strategies for improving kraftliner pulp properties
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A large part of the world paper manufacturing consists of production of corrugated board components, kraftliner and fluting, that are used in many different types of corrugated boxes. Because these boxes are stored and transported, they are often subjected to changes in relative humidity. These changes together with mechanical loads will increase the deformation of the boxes compared to the case where the same loads are applied in a static environment. This enlarged creep due to the changes in relative humidity is called mechano-sorptive or accelerated creep. Mechano-sorptive creep forces producers to use high safety factors when designing boxes, and therefore, this is one of the key properties of kraftliner boards. Different strategies to decrease mechano-sorptive creep, and to simultaneously gain more knowledge about the causes for this phenomenon in paper, are the aim of this work. Derivatised and underivatised black liquor lignins, a by-product produced in pulp mills in large quantities, have been used together with biomimetic methods, to modify the properties of kraftliner pulp. Furthermore, the properties of kraftliner pulp have been compared to other pulps in order to evaluate the influence of fibre morphological factors, such as fibre width and shape factor, on the mechano-sorptive creep. In addition the influence of the chemical composition of the kraftliner pulp has been evaluated both by means of treating a kraftliner pulp with chlorite and xylanase and by producing pulps with different chemical composition. By using lignin and biomimetic methods, to create radical coupling reactions, it has been shown that it is possible to increase the wet strength of kraftliner pulp sheets. This method of treating the pulp showed, however, no significant effects on the mechano-sorptive creep. The addition of an apolar suberin-like lignin derivative, which has been shown to be possible to produce from natural resources, did show a positive effect on mechano-sorptive creep properties, but at the expense of stiffness properties in constant climate. Different pulps were compared with a kraftliner pulp and it was observed that the ratio between tensile stiffness and hygroexpansion can be used to estimate the mechano-sorptive creep properties. The hardwood kraft pulps investigated had lower hygroexpansion, probably due to more slender and straighter fibres, and higher tensile stiffness, probably due to lower lignin content. As the lignin content was varied by different methods in kraft pulps, it was observed that increased lignin content gives an increased hygroexpansion and decreased tensile stiffness as well as an increased mechano-sorptive creep. There were also indications of increased mechano-sorptive creep due to higher xylan content.
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| 2. |
- Claudino, Mauro
(författare)
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Thiol−ene Coupling of Renewable Monomers : at the forefront of bio-based polymeric materials
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Plant derived oils bear intrinsic double-bond functionality that can be utilized directly for the thiol–ene reaction. Although terminal unsaturations are far more reactive than internal ones, studies on the reversible addition of thiyl radicals to 1,2-disubstituted alkenes show that this is an important reaction. To investigate the thiol–ene coupling reaction involving these enes, stoichiometric mixtures of a trifunctional propionate thiol with monounsaturated fatty acid methyl esters (methyl oleate or methyl elaidate) supplemented with 2.0 wt.% Irgacure 184 were subjected to 365-nm UV-irradiation and the chemical changes monitored. Continuous (RT– FTIR) and discontinuous (NMR and FT–Raman) techniques were used to follow the progress of the reaction and reveal details of the products formed. Experimental results supported by numerical kinetic simulations of the system confirm the reaction mechanism showing a very fast cis/trans-isomerization of the alkene monomers (<1.0 min) when compared to the total disappearance of double-bonds, indicating that the rate-limiting step controlling the overall reaction is the hydrogen transfer from the thiol involved in the formation of final product. The loss of total unsaturations equals thiol consumption throughout the entire reaction; although product formation is strongly favoured directly from the trans-ene. This indicates that initial cis/trans-isomer structures affect the kinetics. High thiol–ene conversions could be easily obtained at reasonable rates without major influence of side-reactions demonstrating the suitability of this reaction for network forming purposes from 1,2-disubstituted alkenes. To further illustrate the validity of this concept in the formation of cross-linked thiol–ene films a series of globalide/caprolactone based copolyesters differing in degree of unsaturations along the backbone were photopolymerized in the melt with the same trithiol giving amorphous elastomeric materials with different thermal and viscoelastic properties. High thiol–ene conversions (>80%) were easily attained for all cases at reasonable reaction rates, while maintaining the cure behaviour and independent of functionality. Parallel chain-growth ene homopolymerization was considered negligible when compared with the main coupling route. However, the comonomer feed ratio had impact on the thermoset properties with high ene-density copolymers giving networks with higher glass transition temperature values (Tg) and a narrower distribution of cross-links than films with lower ene composition. The thiol–ene systems evaluated in this study serve as model example for the sustainable use of naturally-occurring 1,2-disubstituted alkenes at making semi-synthetic polymeric materials in high conversions with a range of properties in an environment-friendly way.
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| 3. |
- Cruz, Igor, 1986-
(författare)
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Evaluating the utilisation of industrial excess heat from an energy systems perspective
- 2022
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sweden aims to achieve climate neutrality by 2045. The need to immediately reduce greenhouse gas emissions in order to achieve climate targets affects industry directly. The pulp and paper sector is responsible for more than 50% of industrial energy use in Sweden. Increased energy efficiency is expected to contribute significantly to the reduction of primary energy use. The recovery and utilisation of industrial excess heat (IEH) has been identified as an important potential contribution to energy efficiency in industry. Previous research based on top-down studies has estimated the availability of IEH for entire sectors, and bottom-up results for many case studies are available. While top-down studies lack detailed information on the profile of the excess heat available, bottom-up studies have limited coverage. Detailed information about excess heat amounts and temperature levels is required for the assessment of the potential of the various heat recovery technologies that are available. The aim of this thesis is to present, in a series of steps, methods to systematically analyse an industrial process to obtain a detailed profile of the excess heat available under various process conditions, to aggregate results that can be generalised to whole industrial sectors, and to obtain IEH recovery potentials using different technologies. The assessment of the utilisation options for IEH recovery is complemented with an analysis of system aspects that could affect profitability and global greenhouse gas (GHG) emissions. An energy-targeting procedure combined with optimisation has been applied to six case studies of kraft pulp and paper mills in Sweden. This method obtained IEH profiles that were used in a regression analysis to estimate the IEH availability and electricity generation potentials from low and medium temperature IEH using organic Rankine cycles (ORC). A comparison of profitability and global GHG emissions between ORC electricity generation using IEH and small-scale combined heat and electricity (CHP) production is presented for three energy markets.The results show that there is a potential to increase electricity generation from low and medium temperature IEH by 7–9% in the kraft mills in Sweden, depending on the level of process integration considered. The utilisation of low and medium temperature IEH for electricity generation has the potential to reduce global GHG emissions in all the energy-market scenarios considered, but if biomass is considered a limited resource, district heating (DH) deliveries can achieve higher global GHG reductions. ORC electricity generation from low and medium temperature IEH is economically viable and showed overall better profitability and GHG emissions reductions than small-scale CHP using ORCs. The economic feasibility of ORC electricity generation is less affected by external conditions and uncertainties than direct DH deliveries.
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| 4. |
- Johansson, Karna, 1982-
(författare)
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Altered body composition in adults with complex congenital heart disease
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: Thanks to achievements in paediatric heart surgery and medicine, the population of adults with surgically repaired or palliated congenital heart defects is growing. Many of these adults have reduced exercise capacity, weaker muscular strength and shorter height, all of which suggest an altered body composition.The overall aim of this thesis was to evaluate the body composition, in terms of bone, muscle and fat mass, in adults with complex congenital heart disease (CHD). Changes as such may be of prognostic importance and thus suggest future therapeutic targets outside the traditional hunting grounds of the cardiologist.Material and methods: The overall material consisted of two cohorts. The first cohort, recruited in a Swedish multicentre study, comprised 73 adult patients with complex CHD and 73 controls, matched for age and sex. Participants were examined with full body dual-energy x-ray absorptiometry (DXA), providing muscle, bone and fat mass for arms, legs and trunk respectively (papers I and II).The second cohort, recruited within a single centre study, comprised 49 adult patients with complex CHD and 49 age and sex matched controls. Participants were examined with peripheral quantitative computed tomography (pQCT), providing slices of forearm and calf, describing muscle, bone and fat area and corresponding density (papers III and IV). Muscular strength in selected muscle groups was also evaluated in both cohorts.Results: More than half of the adults with complex CHD had a pathologically low skeletal muscle mass and strength compared to controls, a trait referred to as sarcopenia. There was a strong association between forearm muscle mass and grip strength.Bone mass was lower in adults with complex CHD, according to both DXA and pQCT analyses, also when adjusting for shorter height. Patients also had lower full body bone mineral density (BMD) as measured with DXA. However, analysis of BMD in limbs with pQCT showed no such reduction. Despite this latter finding, the strength-strain index (a surrogate marker for bone strength provided by pQCT in the lower limbs) was still lower in patients compared to controls.Female patients had a higher amount of fat, both in terms of fat mass and proportion of fat, in comparison to controls. The fat mass was predominantly distributed around the internal organs, known as visceral adipose tissue. Male patients showed no such difference regarding fat mass compared to controls.Conclusion: Consequences of living with complex CHD go far beyond the heart; this young population presents a reduced skeletal muscle mass as well as reduced bone strength – both premature traits of frailty, prone to increase with further ageing. Also, women with complex CHD have an increased amount of visceral adipose tissue, which may elevate the risk of acquired heart disease.The extent of future complications remains to be seen. However, the standard treatments for both sarcopenia and osteoporosis include optimal nutritional intake and increased physical exercise. These measures should start sooner rather than later, preferably evaluated through existing quality registers and interventional trials.
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| 5. |
- Johansson, Mats J., 1958-
(författare)
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Gas Exchange in the Normal Lung : Experimental studies on the effects of positive end-expiratory pressure and body position
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- BACKGROUND: The principal function of the lung is gas exchange requiring adequate ventilation and perfusion at the level of the alveoli. The efficiency of gas exchange is depending on the distributions of regional ventilation (V) and pulmonary blood flow (Q) and their correlation.AIMS: To validate a high-resolution method to quantify regional V and to investigate the combined effect of positive end-expiratory pressure (PEEP) and body position on distributions of regional V and Q in the normal lung with mechanical ventilation. To assess the matching of V and Q by calculating ventilation-perfusion ratio (V/Q) heterogeneity, determining the spatial distribution of V/Q and to investigate the role of nitric oxide (NO) in regional V/Q matching.METHODS: Anesthetized mechanically ventilated sheep were studied in prone or supine position with different levels of PEEP (0, 10 and 20 cmH2O). Measurements of regional V were done by determining the deposition of a wet aerosol of fluorescent microspheres (FMS) with a median mass aerodynamic diameter of 1.1 μm, and validated against Technegas. Radioactive microspheres, 15 μm in diameter, were used for determining regional Q. Nitric oxide synthase (NOS) was inhibited with Nω-nitro-L-arginine methyl ester (L-NAME) to evaluate the role of NO on regional V/Q matching. The right lung was dried at total lung capacity and diced in approx. 1000 regions tracking the spatial location of each region.RESULTS: The deposition of FMS mirrored regional deposition of Technegas and thus regional ventilation well. In prone, with PEEP, only a small dorsal redistribution of V but not of Q was observed. The vertical Q gradient was abolished with PEEP in prone position in conflict with the classical zonal model. In supine position both V and Q were distributed with a unimodal gradient and PEEP displaced the mode further dorsally. V/Q heterogeneity was greater in supine than in prone position with and without PEEP. Furthermore, PEEP generated regions with high V/Q in supine but not in prone position. Inhibition of NOS did not change the V/Q distribution in prone position.CONCLUSION: There were marked differences in redistribution of regional ventilation and regional pulmonary blood flow between prone and supine position when PEEP was applied. NO was not an active mechanism for V/Q matching in normal sheep lungs.
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| 6. |
- Olsson, Sara, 1984-
(författare)
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Enhancing UV-protection of clear coated wood by utilizing reactive UV-absorber and epoxyfunctionalized soybean oil
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This work presents the development of a new pretreatment for clear coated wood, that aims to increase the photoprotection of exterior wood products, and at the same time make the system more environmentally friendly. The pretreatment comprises the reactive UV absorber 2-hydroxy-4(2,3-epoxypropoxy)-benzophenone (HEPBP), which has a primary epoxy group that can be covalently attached to the hydroxyl groups of the wood substrate. This reactant is accompanied by renewable epoxy functionalized soybean oil (ESBO), which contains a secondary epoxy group that also has the ability to react with the substrate and that promotes the compatibility between the two reactants. The ESBO further seems to have the advantage of increasing the flexibility of the pretreated veneers as well as decreasing the amount of water in the cell wall of the wood. The study was performed in two parts where the first part focused solely on the development and performance of the pretreatment, whereas the second part used the knowledge gained from part one to evaluate the pretreatment in combination with an acrylic clear coating. Grafting reactions were performed on thin wood veneers heated in solvent. In the first part the reaction parameters, temperature and reaction time, were varied to study their effects on the final properties of the pretreatments. The veneers where then analyzed using FTIR to determine if grafting was achieved. Results show that grafting was successful for reactions performed at temperatures above 90 °C. For part two, grafting was successful for both the boil- and dip process, indicating that a considerably shorter reaction time can be used. Samples from both part one and two where then exposed to accelerated ageing and the color change was measured to estimate the UV-resistance. The first part showed improved UV-resistance for some of the pretreatments, whereas the second part was more difficult to evaluate due to the top coat, but a slight improvement can be seen for samples using the pretreatment. A positive result for part two is also that the pretreatment do not appear to affect the adhesion between the substrate and the top coat. It is hence concluded that the proposed pretreatment is a possible way of increasing the photostability of exterior wood.
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| 7. |
- Tengdelius, Mattias, 1984-
(författare)
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Fucoidan-Mimetic Glycopolymers : Synthesis and Biomedical Applications
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The marine polysaccharide fucoidan has demonstrated several interesting biological properties, for instance being antiviral, anticoagulant, anti-inflammatory, anticancer, and platelet activating. Many of these properties are desirable for various biomedical applications. Yet, there are few reports on fucoidan being used in such applications. The reasons for this are primarily the heterogeneity and low structural reproducibility of fucoidan.This thesis describes the synthesis of polymers with pendant saccharides bearing the key structural features of fucoidan. These glycopolymers were synthesized via different radical polymerization techniques yielding polymers of different chain lengths and dispersity. These glycopolymers showed antiviral and platelet activating properties similar to those of natural fucoidan, thus making them fucoidan-mimetic glycopolymers. However, compared to fucoidan from natural sources, the fucoidan-mimetic glycopolymers had homogeneous and reproducible structures making them suitable for biomedical applications.Further studies demonstrated that platelet activation, caused by these glycopolymers, showed dose-response curves almost identical to fucoidan. The platelet activation was induced via intracellular signaling and caused platelet surface changes similar to those of fucoidan. Fucoidan-mimetic glycopolymers can therefore be used as unique biomolecular tools for studying the molecular and cellular responses of human platelets.Fucoidan-mimetic glycopolymers generally assert their antiviral activity by blocking viral entry to host cells, thus inhibiting spreading of the viral infection but not acting virucidal, i.e. not killing the viruses. Introduction of hydrophobic groups to the polymer’s chain ends improved the antiviral properties significantly and is an important step towards yielding glycopolymers with virucidal properties.The fucoidan-mimetic glycopolymers were also applied as capping agents when synthesizing gold nanoparticles. These fucoidan-mimetic glycopolymer coated gold nanoparticles showed improved colloidal stability compared to uncapped gold nanoparticles. Furthermore, the nanoparticles also demonstrated selective cytotoxicity against a human colon cancer cell line over fibroblast cells.
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| 8. |
- Afrell, Maria, 1953-
(författare)
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Att leva med en kropp som värker : samtal med fysioterapeuten
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background and aim: Physiotherapists in primary care meet, assess and treat patients with long-standing benign musculoskeletal pain. As a clinical condition, long-standing pain is common but nonetheless it is quite complex. The aim of this thesis has been, from a bodily existential perspective, to investigate and conceptualise the experience of living with longstanding benign musculoskeletal pain, and from there, to work out a method for conversation and assessment within non-specialised physiotherapy.Methods: Our first study was an interview study where we applied a phenomenological approach and investigated the ways individuals suffering from long-standing pain experienced their body and their illness. Four aspects of body experience were described, and based on these aspects, four typologies of attitudes to pain were distinguished. In the second study, we made two group interviews with six physiotherapists about their experiences of using, in their clinical work, questions from the interview guide in study I that had given particularly rich responses. Transcripts were analysed using phenomenography. In the third study, patients’ verbal responses to the key questions, directed to them by physiotherapists in clinical situations, were investigated, and the four aspects of body experience from study I formed the concepts of a deductive analysis. In study IV, finally, the key questions and typologies were tried by a larger group (31), and their experiences and the possible applicability of the method were studied by qualitative content analysis combined with the counting of codes.Results: We created four typologies of attitudes to long-standing pain: “Surrendering to one’s fate”, “Accepting by an active process of change”, “Balancing between hope and resignation” and “Rejecting the body”. These typologies, in turn, were based on four aspects of body experience: “The body as an aspect of identity”. “Body reliance”, “Body awareness”, and “Ways of understanding pain”. In study II, by the aid of key questions, patient and physiotherapist managed to have a conversation on bodily existential matters. The physiotherapist learnt to know the patient as a person, a process appeared to be initiated in the patient, and their relation changed. The patient was willing to talk about her body in pain, and had the words to do this. In study III, the key questions opened ways to reflections on body, existence, and biography. The four aspects of body experience were central to the patients’ descriptions. In study IV, the participating physiotherapists reported by large positive experiences from applying key questions and typologies. The patients reflected, emotions were evoked, and the relation and the communication often improved. The typologies helped in giving a comprehensive perspective of the patient’s problem, and to grasp where in the process of rehabilitation the patient was to be found.Conclusions: The method, seven key questions combined with the tentative frame of interpretation of the answers, seemed to be easily applied by interested physiotherapists in non-specialised practice. The application of the method addresses the need of developing the professional role of the physiotherapist. The challenge is to face the whole person, who is her lived body as well as her identity crisis, carried by emotions such as grief and anger. This may inspire the use of the full potential of the physiotherapist’s professional role in the clinical encounter.
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| 9. |
- Alipour, Nazanin, 1978-
(författare)
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Structure and Mechanical/Transport properties of Single and Multilayer Polyethylene-based Materials
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The current study discusses the structure, mechanical and transport properties of polyethylene-based materials into two parts. The first part deals with the migration and chemical depletion of active substance such as insecticides from moulded polyethylene sheets. Deltamethrin (DM) and synergist piperonyl butoxide (PBO) are often used for insect control purpose. It was found that DM as a powder was incapable of recrystallization and remained in liquid state after cooling to room temperature, and that the evaporation of a DM/PBO solution was greater than that predicted from the evaporation rates of pristine separate material components. Infrared spectroscopy and liquid chromatography showed that the loss of DM and PBO through polyethylene sheets was negligible over 30 days, when aged in air at 80 °C (60 and 80 %RH). However, significant migration of the active species was observed in aged polyethylene sheets which were exposed in liquid water (at 80 and 95 °C). In the second part, the structure and properties of multi–layered polymer films were studied in terms of crystallization kinetics, mechanical and transport properties. Previously, it has been shown that when the layer thickness decreases from micrometre-scale to nanometre-scale, leading to improvement of the film performance such as crack propagation and oxygen barrier properties. In this work, two multi-layered systems were considered based on compatible (i) or incompatible layers (ii). In the first case (i), metallocene polyethylene (mPE) and low-density polyethylene (LDPE) where investigated as 2, 24, and 288 adjacent layers. In the second case (ii) poly(ethylene-co-vinyl alcohol) (EVOH) and polyethylene adhesive was evaluated as 5 and 19 layers. The crystallization kinetic studies showed that the crystallization rate was retarded as the layers became thinner with increasing number of layers in the multi-layered films as compared to the reference films (2 and 5 layers). The observation was suggested to stem from greater association between layers (inter layer mixing) in the case of mPE/LDPE films with 2 layers. Furthermore, the crack growth resistance increased with increasing number of layers. The x-ray scattering and tensile testing showed that the films were orientated more in extrusion direction than in the transverse direction, besides the EVOH films (the incompatible system) showed higher orientation in the extrusion direction than mPE/LDPE films. The uptake of n-hexane was reduced significantly in multi-layered EVOH films due to the effective protective role of EVOH. Furthermore, it was revealed that non-homogenous swelling causing a folding/curling of bilayer films when exposed to the vapour of the solvent.
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| 10. |
- Andersson, Anna, 1974-
(författare)
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A framework supporting the collaboration between the logistics- and the product development process
- 2007
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the competitive environment of today’s global markets, the demands of customers are increasing. They expect to get the best product at the lowest price with immediate availability. Logistics, including transportation, inventory maintenance, order processing, purchasing, warehousing, materials handling, packaging, customer service standards, and product scheduling must continuously be developed to meet the challenges of the market. The globalization, with longer distances to customers and suppliers, and the progressing trend of outsourcing are examples of why the importance of logistics has increased over the last few years.A considerable part of the final product cost is frozen during the early product development phases. In the early phases of the product development process, the cost of making design changes is low compared to making changes later in the product development process. The product development decisions made in the early phases of the product development process have considerable impact on future manufacturing and logistics activities as well.The objective of this research project is to develop a framework supporting the collaboration between the logistics- and the product development process. To do this, it has been essential to analyze which parameters influence the efficiency of the logistics process and the interface between the logistics- and the product development process. Also, to investigate how the logistics department can be integrated earlier in the product development process has been of interest. This has been done through both a theoretical review and also through a number of case studies.The result and conclusion of this project is a framework that gives support for what to focus on, how to collaborate, in which phases collaboration is meaningful, and which persons need to be involved in the different product development phases. Working as the framework suggests will, hopefully, give closer collaboration between the logistics- and the product development process than without this supportive framework. The expectation of the collaboration is an earlier integration of the logistics department in the product development process and through this influence and increase the efficiency of the logistics process.
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