| 1. |
- Nilsson, Maria, 1957-
(author)
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Promoting health in adolescents : preventing the use of tobacco
- 2009
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Doctoral thesis (other academic/artistic)abstract
- There is a robust evidence base for the negative health effects from smoking. Smoking is linked to severe morbidity and to mortality, and kills up to half of its regular users. Tobacco use and production also bring other negative consequences such as economic loss for countries, poverty for individuals, child labour, deforestation and other environmental problems in tobacco growing countries. A combination of comprehensive interventions at different levels is needed to curb the tobacco epidemic. Tobacco control strategies at national levels in the western world often include components of information/education, taxation, legislative measures and influencing public opinion. Two approaches have dominated at the meso and micro levels: cessation support for tobacco users and prevention activities to support young people refraining from tobacco use. Smoking uptake is a complex process that includes factors at the societal level as well as social and individual characteristics. At national level, taxation and legislation can contribute to a societal norm opposing tobacco and creating a context for primary prevention aimed at tobacco free youth. There is no magic bullet in primary prevention. At the meso and micro levels, a continued development of knowledge on the underlying mechanisms and primary prevention methods is essential to prevent young people from starting to use tobacco. The overall aim of this thesis was to gain knowledge about factors that influence young people’s use of tobacco and of preventive mechanisms. The specific aims included to study the relation between Tobacco Free Duo, an intervention program targeting youth in Västerbotten County, and tobacco use prevalence. A specific interest was to explore the role adults can play in supporting young people to refrain from tobacco use. The thesis is based on four studies with three separate sets of data, two were quantitative and one was qualitative. The studies were conducted among adolescents (aged 13-15 yr) in Västerbotten County and on national level in Sweden (aged 13, 15 and 17 yr). Tobacco Free Duo is a school-based community intervention that started in 1993. An essential component of the intervention was to involve adults in supporting adolescents to stay tobacco free. Results showed decreased smoking in adolescents among both boys and girls in the intervention area during the study period of seven years. There was no change in a national reference group during the same time period. A bonus effect was a decrease in adult tobacco use in the intervention area. One out of four adults who supported a young person taking part in the intervention stopped using tobacco. In a qualitative assessment of young smokers, starting to smoke was described as a means of gaining control of their feelings and their situation during early adolescence. They expected adults to intervene against their smoking and claimed that close relations with caring adults could be a reason for smoking less or trying to quit smoking. In a quantitative study that used three decades of national data, over time adolescents became more positive toward parental action on children’s smoking. The adolescents strongly supported the idea of parental action, regardless of whether or not they themselves smoked. Adolescents preferred that actions from parents were dissuading their children from smoking, not smoking themselves, and not allowing their children to smoke at home. These results suggest that the Tobacco Free Duo program contributed to a reduction in adolescent smoking among both boys and girls. Using a multi-faceted intervention that includes an adolescent-adult partnership can decrease adolescent smoking uptake. Engaging adults as partners in tobacco prevention interventions that target adolescents has an important tobacco reducing bonus effect in the adults. The intervention has proven sustainable within communities. A growing majority of adolescents support parental interventions to help them refrain from tobacco. The findings dismiss the notion that adolescents ignore or even disdain parental practices concerning tobacco. A common and consequent norm against tobacco from both schools and parents using a supportive attitude can prevent tobacco use in young people.
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| 2. |
- Petersson, Erik, 1985-
(author)
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Vadstena krigsmanshus : En studie av den svenska kronans inrättning för sårade och gamla soldater cirka 1640–1780
- 2017
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Doctoral thesis (other academic/artistic)abstract
- Den här avhandlingen handlar det underhåll till sårade och gamla soldater som den svenskastatsmakten organiserade under tidigmodern tid. Undersökningen tar sin utgångspunkt i den tid närstatsmakten började organisera mer omfattande hjälp för soldater, vilket var slutet på Gustav Vasasoch under Erik XIV:s regeringstid i mitten av 1500-talet. Motiven till att statsmakten organiseradehjälp för en del soldater var att dessa skulle ha offrat sin hälsa och arbetsförmåga i kronans tjänst, menså länge statsmakten fortsatte att vara relativt löst organiserad var även hjälpen till soldaterna avganska liten omfattning. Det ändrades under Gustav II Adolfs regering då planerna på att skapa ettkrigsmanshus i Vadstena etablerades, vilka senare genomfördes efter hans död och institutionen kundeta emot de första soldaterna senast 1640. I krigsmanshuset fick ett trettiotal soldater med familjeruppehälle, samtidigt som soldater boende i andra delar av landet fick stöd från krigsmanshuskassansom också administrerades från Vadstena. Mot slutet av 1600-talet blev kassan proportionellt merbetydelsefull än krigsmanshuset och runt år 1700 försörjde kassan flera tusen soldater runtom i riket.1700-talet innebar stora förändringar, bland annat genom att krigen blev färre, att krigaryrket intelängre var lika attraktivt som karriärväg för adelsmän och att statsmakten utvecklade andra mer civiladelar. Behovet av ett krigsmanshus fanns till sist inte längre och institutionen i Vadstena stängde förboende våren 1784, men kassan fanns kvar in på 1970-talet.
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| 3. |
- Strandberg, Gustav, 1977-
(author)
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Modelling regional climate-vegetation interactions in Europe : A palaeo perspective
- 2017
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Doctoral thesis (other academic/artistic)abstract
- Studies in paleoclimate are important because they give us knowledge about how the climate system works and puts the current climate change in necessary perspective. By studying (pre)historic periods we increase our knowledge not just about these periods, but also about the processes that are important for climatic variations and changes. This thesis deals mainly with the interaction between climate and vegetation. Vegetation changes can affect climate in many different ways. These effects can be divided into two main categories: biogeochemical and biogeophysical processes. This thesis studies the biogeophysical effects of vegetation changes on climate in climate models. Climate models are a necessary tool for investigating how climate responds to changes in the climate system, as well as for making predictions of future climate. The biogeophysical processes are strongly related to characteristics of the land surface. Vegetation changes alter the land surface’s albedo (ability to reflect incoming solar radiation), roughness and evapotranspiration (the sum of evaporation and tran-spiration), which in turn affects the energy fluxes between the land surface and the atmosphere and thereby the climate. It is not, however, evident in what way; denser vegetation (e.g. forest instead of grassland) gives decreased albedo, which results in higher temperature, but also increased evapotranspiration, which contrastingly results in lower temperature. Vegetation changes are in this thesis studied in four different (pre)historic periods: two very cold periods with no human influence (c. 44,000 and 21,000 years ago), one warm period with minor human influence (c. 6,000 years ago) and a cold period with substantial human influence (c. 200 years ago). In addition to that the present climate is studied. The combination of these periods gives an estimate of the effect of both natural and anthropogenic vegetation on climate in different climatic contexts. The results show that vegetation changes can change temperature with 1–3 °C depending on season and region. The response is not the same everywhere, but depends on local properties of the land surface. During the winter half of the year, the albedo effect is usually most important as the difference in albedo between forest and open land is very large. During the summer half of the year the evapotranspiration effect is usually most important as differences in albedo between different vegetation types are smaller. A prerequisite for differences in evapotranspiration is that there is sufficient amount of water available. In dry regions, evapotranspiration does not change much with changes in vegetation, which means that the albedo effect will dominate also in summer. The conclusion of these studies is that vegetation changes can have a considerable effect on climate, comparable to the effect of increasing amounts of greenhouse gases in scenarios of future climate. Thus, it is important to have an appropriate description of the vegetation in studies of past, present and future climate. This means that vegetation has the potential to work as a feedback mechanism to natural climatic variations, but also that man can alter climate by altering the vegetation. It also means that mankind may have influenced climate before we started to use fossil fuel. Consequently, vegetation changes can be used as a means to mitigate climate change locally.
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| 4. |
- Thiagarajan, Kannan, 1981-
(author)
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Tight-binding calculations of electron scattering rates in semiconducting zigzag carbon nanotubes
- 2011
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Licentiate thesis (other academic/artistic)abstract
- The technological interest in a material depends very much on its electrical, magnetic, optical and/or mechanical properties. In carbon nanotubes the atoms form a cylindrical structure with a diameter of the order 1 nm, but the nanotubes can be up to several hundred micrometers in length. This makes carbon nanotubes a remarkable model for one-dimensional systems. A lot of efforts have been dedicated to manufacturing carbon nanotubes, which is expected to be the material for the next generation of devices. Despite all the attention that carbon nanotubes have received from the scientific community, only rather limited progress has been made in the theoretical understanding of their physical properties. In this work, we attempt to provide an understanding of the electron-phonon and electron-defect interactions in semiconducting zigzag carbon nanotubes using a tight-binding approach. The electronic energy dispersion relations are calculated by applying the zone-folding technique to the dispersion relations of graphene. A fourth-nearest-neighbour force constant model has been applied to study the vibrational modes in the carbon nanotubes. Both the electron-phonon interaction and the electron-defect interaction are formulated within the tight-binding approximation, and analyzed in terms of their quantum mechanical scattering rates. Apart from the scattering rates, their components in terms of phonon absorption, phonon emission, backscattering and forward scattering have been determined and analyzed. The scattering rates for (5,0), (7,0), (10,0), (13,0) and (25,0) carbon nanotubes at room temperature and at 10K are presented and discussed. The phonon scattering rate is dependent on the lattice temperature in the interval 0-0.17 eV. We find that backscattering and phonon emission are dominant over forward scattering and phonon absorption in most of the energy interval. However, forward scattering and phonon absorption can be comparable to backscattering and phonon emission in limited energy intervals. The phonon modes associated with each peak in the electron-phonon scattering rates have been identified, and the similarities in the phonon scattering rates between different nanotubes are discussed. The dependence of the defect scattering rate on the tube diameter is similar to that of the phonon scattering rate. Both the phonon and the defect scattering rates show strong dependence on the tube diameter (i.e., the scattering rate decreases as a function of the index of the nanotube). It is observed that the backscattering and forward scattering for electrons interacting with defects occur with same frequency at all energies, in sharp contrast to the situation for phonon scattering. It is demonstrated that the differences in the scattering rate between different tubes are mainly due to the differences in their band structures.
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| 5. |
- Unander, Tomas
(author)
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Characterization of Low Cost Printed Sensors for Smart Packaging
- 2008
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Licentiate thesis (other academic/artistic)abstract
- Currently there are very significant interests in printed electronics in the world. The possibility to produce electronics in a roll to roll printing process will considerably reduce the cost of the electronic devices. However, these new devices will most probably not replace the traditional silicon based electronics, but will be a complement in low cost applications such as in intelligent packages and other printable media. One interesting area is printable low cost sensors that add value to packages. In this thesis a study of the performance of low cost sensors is presented. The sensors were fabricated using commercial printing processes used in the graphical printing business. The sensors were characterized and evaluated for the intended application. The evaluated sensors were moisture sensing sensor solutions and touch sensitive sensor solutions. A printable touch sensitive sensor solution is presented where the sensor is incorporated into a high quality image such as in point of sales displays. The sensor solution showed good touch sensitivity at a variety of humidity levels. Four printed moisture sensor concepts are presented and characterized. Firstly, a moisture sensor that shows good correlation to the moisture content of cellulose based substrates. Secondly, a sensor that measures the relative humidity in the air, the sensor has a measuring accuracy of 0.22% at high relative humidity levels. Thirdly, a moisture sensor that utilizes unsintered silver nano-particles to measure the relative humidity in the air, the sensor has a linear response at very low relative humidity levels. And fourth, an action activated energy cell that provides power when activated by moisture. A concept of remote moisture sensing that utilizes ordinary low cost RFID tags has also been presented and characterized. The remote sensor solution works both with passive and semi-passive RFID systems. The study shows that it is possible to manufacture low cost sensors in commercial printing processes.
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| 6. |
- Unander, Tomas
(author)
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System integration of electronic functionality in packaging application
- 2011
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Doctoral thesis (other academic/artistic)abstract
- Sensor applications are becoming increasingly important as products are now being requested to be more and more intelligent and safe. As the costs involved in sensor technology decrease its usage will spread to new market segments including new areas with products that have never previously used such functionalities, including, wood fibre based products for packaging, hygiene or graphical use. Currently there is a significant interest in developing technology that will allow packages to become interactive and be integrated with digital services accessible on the Internet. In this thesis, the system integration of a hybrid RFID based sensor platform is presented. This proposed platform provides a trade-off between the communication performance and its compatibility with international standards and also includes flexibility in on‐package customization, including the type and number of sensors. In addition it combines the use of traditional silicon based electronics with printed electronics directly onto wood fibre based materials so as to enable the possibility of creating smart packages. Together with the system integration of the sensor platform, five printed moisture sensor concepts that are designed to work with the sensor platform are presented and characterized. Firstly, there is a moisture sensor that shows a good correlation to the moisture content of wood fibre based substrates. The second one involves a sensor that detects high relative humidity levels in the air and the third is an action activated energy cell that provides power when activated by moisture. The fourth one deals with two types of moisture sensors that utilize silver nano-particles in order to measure the relative humidity in the air. The final one is a printable touch sensitive sensor that is sensitive to the moisture contained in the hand. A concept of remote moisture sensing that utilizes ordinary low cost RFID tags has also been presented and characterized.The main focus is thus on system integration to, by combining silicon based electronics with printed electronics, find the most low cost solution with regards to flexibility, sensor functions and still meet the communication standards.
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| 7. |
- Öhlund, Thomas
(author)
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Metal Films for Printed Electronics : Ink-substrate Interactions and Sintering
- 2014
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Doctoral thesis (other academic/artistic)abstract
- A new manufacturing paradigm may lower the cost and environmental impact of existing products, as well as enable completely new products. Large scale, roll-to-roll manufacturing of flexible electronics and other functionality has great potential. However, a commercial breakthrough depends on a lower consumption of materials and energy compared with competing alternatives, and that sufficiently high performance and reliability of the products can be maintained. The substrate constitutes a large part of the product, and therefore its cost and environmental sustainability are important. Electrically conducting thin films are required in many functional devices and applications. In demanding applications, metal films offer the highest conductivity. In this thesis, paper substrates of various type and construction were characterized, and the characteristics were related to the performance of inkjet-printed metal patterns. Fast absorption of the ink carrier was beneficial for well-defined pattern geometry, as well as high conductivity. Surface roughness with topography variations of sufficiently large amplitude and frequency, was detrimental to the pattern definition and conductivity. Porosity was another important factor, where the characteristic pore size was much more important than the total pore volume. Apparent surface energy was important for non-absorbing substrates, but of limited importance for coatings with a high absorption rate. Applying thin polymer–based coatings on flexible non-porous films to provide a mechanism for ink solvent removal, improved the pattern definition significantly. Inkjet-printing of a ZnO-dispersion on uncoated paper provided a thin spot-coating, allowing conductivity of silver nanoparticle films. Conductive nanoparticle films could not form directly on the uncoated paper. The resulting performance of printed metal patterns was highly dependent on a well adapted sintering methodology. Several sintering methods were examined in this thesis, including conventional oven sintering, electrical sintering, microwave sintering, chemical sintering and intense pulsed light sintering. Specially designed coated papers with modified chemical and physical properties, were utilized for chemical low-temperature sintering of silver nanoparticle inks. For intense pulsed light sintering and material conversion of patterns, custom equipment was designed and built. Using the equipment, inkjet-printed copper oxide patterns were processed into highly conducting copper patterns. Custom-designed papers with mesoporous coatings and porous precoatings improved the reliablility and performance of the reduction and sintering process. The thesis aims to clarify how ink-substrate interactions and sintering methodology affect the performance and reliability of inkjet-printed nanoparticle patterns on flexible substrates. This improves the selection, adaptation, design and manufacturing of suitable substrates for inkjet-printed high conductivity patterns, such as circuit boards or RFID antennas.
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| 8. |
- Hammarling, Krister, 1968-
(author)
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Hydrogel-based pH-sensors : Development and characterisation of optical and electrical pH sensors based on stimuli-responsive hydrogels
- 2019
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Doctoral thesis (other academic/artistic)abstract
- The ability to measure the chemical parameter pH is of high importance in many areas. With new government regulations and evolving markets, there is a strong motivation for improving such measurements and conducting research on new types of pH sensors and sensor materials. Stimuli-responsive hydrogels (a group of polymers) have attracted a lot of attention in recent decades, due to their ability to be customized to suit many applications. One specific area where they have attracted attention is pH sensor technology.Two stimuli-responsive hydrogels are used in this thesis. One is a non-toxic hydrogel, 1,4-acryl-terminated oligo(beta-amino esters) (1,4-AOBAE). Although it was previously used in drug- and DNA- delivery systems, it has not (to my knowledge) been used in a sensor configuration, and thus it is interesting to study. The second hydrogel, 1,3-acryl-terminated oligo(beta-amino esters) (1,3-AOBAE), is an improved variant of the first one. This improved hydrogel was synthesized because the original hydrogel crystallizes at room temperature, which meant that it was not optimal for various coating techniques. This hydrogel was characterized and verified for pH responsivity in two sensor configurations: electrical and optical. Designing a hydrogel for a specific application can be a complex procedure due to the many synthesizing parameters. For example, increasing a hydrogel's mechanical strength by introducing a higher degree of cross linking, leads to a smaller mesh size, which in turn leads to a lower diffusion rate and less solution absorption. The two hydrogels examined in this thesis respond to pH changes by absorbing or desorbing water; this change in the hydrogel's water content also changes its effective refractive index and permittivity. These changes can be measured using optical or electrical sensor systems. Three types of sensor systems were used in this thesis to verify the hydrogel's pH response and to ensure that they are suitable for use in thin-film techniques on various substrates (e.g. glass and plastic). The experimental results prove that these hydrogels are suitable for use in both electrical and optical sensor configurations. For electrical systems, a pH range of approximately 3-12 was achieved, and for optical, the range was approximately 2-12. These ranges can likely be improved, as the sensor film delaminated from the substrate at low pHs due to adhesion problems and as measurements above 12 were not conducted.The findings of this thesis could, after more research, have strong implications for the development of improved pH-sensor configurations, especially for medical and healthcare applications and in environmental monitoring.
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| 9. |
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| 10. |
- Sidén, Johan
(author)
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On the Design, Characterization and Optimization of RFID Tag Antennas
- 2007
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Doctoral thesis (other academic/artistic)abstract
- Remotely read electronic identification tags are establishing as the standard method of identifying objects in transport logistcs. They are referred to as RFID tags and with successful research and development they are likely to one day replace all of todays barcodes, found on a wide variety of items and objects. As RFID systems consist of many different parts spanning over just as many academic subjects, this thesis investigates some of the main issues regarding RFID tag antennas. Large focus is put on performance and cost optimization of relatively simple one‐layer antennas, suitable for mass production in commercial printing presses using electrically conductive ink. Examples of specially designed antennas include ones that can operate upon metallic objects and antennas that can be physicall bent. It is also shown how RFID tag antennas that will be widely exposed to the human eye can include a commercial value by letting heir geometric design originate from group insignias and company logos. The thesis also presents a solution of how pairs of ordinary low cost RFID tags can be used as remotely read moisture sensors.
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