Effekten av torka på gran kan var stor. Sommaren 2018 var en av de torraste och varmaste somrarna på länge. En sådan period påverkar ofta granars vitalitet negativt och kan leda till en ökad risk för angrepp av granbarkborre. Denna studie har undersökt hur årsringsbredden på gran har förändrats till följd av torka genom att jämföra årsringsbredder före torkperioden med de efter. Mätningar genomfördes med en resistograf som genererade datafiler som sedan sammanställdes och analyserades, främst med hjälp av Excel. Vidare noterades markfuktighet, bonitet och angrepp av granbarkborre. Dessa faktorer jämfördes med varandra med syfte att finna eventuella samband. Studiens resultat visar att torkperioden 2018 haft en stor inverkan på granars vitalitet. Dessutom har samband mellan torrare bestånd och antal granar angripna av granbarkborre kunnat påvisas. Samband mellan minskad årsringsbredd och angrepp av granbarkborre har ej kunnat fastställas.

Previous studies of saw marks have primarily focused on morphological characteristics and their utility in identifying saws suspected to have been utilized in cases of criminal dismemberment. The present study examined the extent to which metric analysis may be used to correlate saw blades measurements of kerf width. A sample of 56 partially defleshed white-tailed deer (Odocoileus virginianus) limbs were utilized as a proxy for human remains. The partial limbs were cut using a variety of commercially available saws, including 11 manual-powered saws and 5 mechanical-powered saws. A total of 500 false start kerfs (FSKs) were measured using digital calipers. Two experiments were performed, with the first test examining the kerf widths of false starts produced on specimens that were restrained using clamps, while the second test analyzed the kerf widths of false starts produced on minimally restrained specimens. Statistical analysis using Hierarchical Linear Modeling indicated a positive relationship between saw blade width (mm) and minimum kerf width (MKW), with the model estimating that MKWs would increase by 1.61 mm for every millimeter increase in blade width. Results from the models indicated that blade width (p<0.001) and the difference between mechanical- and manual-powered saws (p=0.029) were considered statistically significant. A comparison of MKWs produced using manual-powered saws on unrestrained and restrained bones suggests that restraint condition (p=0.009) is statistically significant. In comparisons of MKWs to blade widths, the average ratio for used saws was 2.7% greater than the average ratio for new saws. The mode of the ratios was approximately 1.4, supporting the general rule that MKW does not exceed 1.5 times saw blade width.

Resource degradation is a significant problem in the world, which is directly related to the textile and fashion industry. Efficient use of the material has been identified as an essential aspect to be addressed seriously. It is a critical topic that has attracted the attention of people and companies in recent years and has become a fundamental issue of sustainability. This research study was based on UN sustainable development goals number 12 and 8, which focuses on resource efficiency. The research is designed in considering fabric consumption, which has a significant impact on the textile and clothing industry to contribute to a brighter future and a more sustainable life. The purpose of this study is to reduce the fabric consumption through improving marker efficiency. The research focuses on investigating the behaviour of marker efficiency concerning usable fabric widths, markers with different sizes and marker with style combinations to reduce fabric consumption. The improvements of the existing markers lead to reduce fabric wastage during the cutting process while improving resource efficiency in consumption and production. In this study, the explanatory sequential design of mixed research method is employed with carrying out experiments to collect and analyze quantitative data, explained and elaborated with qualitative findings through expert interviews to get insights into the quantitative findings in a deductive approach. The marker efficiency significantly varies according to the combination of sizes and style and usable fabric width. The improvements of the marker efficiency, reduce the fabric consumption per garment and increase resource efficiency while preventing waste generation. A saving of 1% of a material which consumed millions of tons per year, significantly affect on reducing resource depletion and environmental pollution. This study is limited to five usable fabric widths, four size marker combinations and two style combinations. Moreover, it is focused on material efficiency, and cost efficiency is not considered. There are possibilities for clothing manufactures’ to improve resource efficiency by improving marker efficiency while planning the demand, considering multi-size and multi-style markers. They can concern usable fabric widths, which provide higher marker efficiencies during material purchasing.

A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry. Objective: This study aimed to determine and compare the esthetic preference of the general public, dentists, orthodontists and prosthodontists in relation to the width of the most anatomically variable tooth in the mouth, the maxillary lateral incisor. Background: The general public today places more importance on facial esthetics than they have in the past and their esthetic preferences are evolving. The smile is a main feature of facial esthetics and its attractiveness is based in part on the size and proportion of the anterior teeth. The lateral incisors are the most variable in size and there is a continuing debate in the literature with conflicting reports about how wide they should be in proportion to their neighboring teeth. Methods: Two sets of seven images of frontal and oblique (three-quarter) smile views were created with Adobe Photoshop Elements 10 by morphing two "Master Smile" images. The seven images within each set had different width proportions of lateral incisors. However, they were identical in every other aspect such as differences in lip thickness or tooth shape to diminish the impact of compounding variables between photographs. A link to an online survey was distributed by email to four groups: laypeople, general dentists, orthodontists and prosthodontists. Subjects taking the survey ranked the seven photographs in each set from the most to the least esthetic based on their personal preference. The results were studied to ascertain whether the general public has an esthetic preference in the width of lateral incisors and, if that preference exists, whether it is different from that of trained dental professionals. Results: In a frontal view of a smile, the global preference for the width of a lateral incisor falls into the range of 62.5-72.5% of the width of the central incisor. The probability that the most preferred choice is 67.5% or greater is 66%. In the frontal view there was no statistically significant difference between professions. Non-Hispanic white respondents preferred slightly more narrow laterals than other ethnicities in the frontal view. Respondents older than forty preferred slightly wider laterals than respondents under forty in the frontal view. In the oblique view, there was a 69% probability that the most preferred choice was the largest option: a lateral incisor 91.5% of the width of the visible width of the central incisor. In the oblique view, the three groups of dental professionals were more likely than the general public to select a wider incisor as the most esthetic option. Conclusion: Preference for smile attractiveness can be significantly influenced by the width of lateral incisors in a frontal and oblique view. Orthodontist, general dentists, and prosthodontists were shown to be in general agreement with the public in preferring a wider lateral incisor viewed from a frontal smile. In an oblique view, their professions had a statistically significant impact on the difference between their choices compared to laypeople in that they preferred a slightly wider lateral incisor. All groups preferred significantly wider laterals than is proscribed by the Golden Proportion.

Spontanious sporting has for the last decades reduced and is today not as common as it was before. The effect of this evolution has been that people are much more inactive and the risk for population diseases has increased. This means that the organized sporting has become more important for the public health, especially for adolescents. But for the last years the number of adolescents that drops out from organizational sports between the ages of 16 to 20 years old has been increasing, which is a problem. A document called “Idrotten vill” has because of that problem been made with the content for how the sport movement should be conducted for the different age groups. The aim for this study has been to gain an insight into how five organizational sports clubs in northern Sweden are conducting their sports for adolescents by the guidelines from “Idrotten vill” and what possible differences there may be between organizational sport clubs focused on individual sports and team sports. To get the information needed five interviews was made with five different people from organizational sports, divided in three individual sports and two team sports. The result shows that the organizational sports are conducting their sports for adolescents by the guidelines from “Idrotten vill” with some differences between the individual sports and team sports.

No description available.

A dominating source for the radiated acoustic noise from a train at low speeds is the traction motor. This noise originates from electromagnetic forces acting on the structure resulting in vibrations on the surface and thus radiated noise. It is often perceived as annoying due to its tonal nature. To achieve a desirable acoustic behavior, and also to meet legal requirements, it is of great importance to thoroughly understand the generation of noise of electromagnetic origin in the motor and also to be able to control it to a low level. In this work, experimental tests have been performed on a traction motor operated from pulse width modulated (PWM) converter. A PWM converter outputs a quasi-sinusoidal voltage created from switched voltage pulses of different widths. The resulting main vibrations at PWM operation and their causes have been analyzed. It is concluded that an appropriate selection of the PWM switching frequency, that is the rate at which the voltage is switched, is a powerful tool to influence the noise of electromagnetic origin. Changing the switching frequency shifts the frequencies of the exciting electromagnetic forces. Further experimental investigations show that the trend is that the resulting sound power level decreases with increasing switching frequency and eventually the sound power level reaches an almost constant level. The underlying physical phenomena for the reduced sound power level is different for different frequency ranges. It is proposed that the traction motor, similar to a thin walled cylindrical structure, shows a constant vibration over force response above a certain frequency. This is investigated using numerical simulations of simplified models. Above this certain frequency, where the area of high modal density is dominating, the noise reducing effect of further increasing the switching frequency is limited. / <p>QC 20180109</p>

Non-equilibrium surface growth for competitive growth models in (1+1) dimensions, particularly mixing random deposition (RD) with correlated growth process which occur with probability $p$ are studied. The composite mixtures are found to be in the universality class of the correlated growth process, and a nonuniversal exponent $\delta$ is identified in the scaling in $p$. The only effects of the RD admixture are dilations of the time and height scales which result in a slowdown of the dynamics of building up the correlations. The bulk morphology is taken into account and is reflected in the surface roughening, as well as the scaling behavior. It is found that the continuum equations and scaling laws for RD added, in particular, to Kardar-Parisi-Zhang (KPZ) processes are partly determined from the underlying bulk structures. Nonequilibrium surface growth analysis are also applied to a study of the static and dynamic load balancing for a conservative update algorithm for Parallel Discrete Event Simulations (PDES). This load balancing is governed by the KPZ equation. For uneven load distributions in conservative PDES simulations, the simulated (virtual) time horizon (VTH) per Processing Element (PE) and the imulated time horizon per volume element $N_{v}$ are used to study the PEs progress in terms of utilization. The width of these time horizons relates to the desynchronization of the system of processors, and is related to the memory requirements of the PEs. The utilization increases when the dynamic, rather than static, load balancing is performed.

The solution of the undergoing climate and energy crises requires a radical transformation of the energy system, in which sustainability, no carbon emissions and energy efficiency ought to play a paramount role.  This revolution should extend to all areas of the energy system, including the space heating and cooling sector, which accounts for a third of the European final energy demand and, in the European continent, it is still mostly supplied by fossil fuels. District heating is a simple but powerful technology that can contribute to tackle this challenge. As a network infrastructure, it is characterised by the flexibility of the heat production, allowing the incorporation of a wide range of heat sources over time. Furthermore, it enables the recycling of heat that would otherwise be wasted and the use of local heat sources in a more cost-effective manner. Moreover, its coupling with the electricity sector can facilitate the increase of intermittent electric renewable energy sources.  Nevertheless, at the moment, district heating only covers a tenth of the European space heating and cooling needs, albeit with significant differences among countries. In addition, the development of new district heating networks is capital intensive and can only be justified in those areas where the concentration of the heat demand is sufficiently high to deliver a lower cost to society than an individual alternative.  Therefore, it is crucial to assess the potential of district heating and to identify the target areas for in-depth investigations. This necessity demands easy and straightforward tools, which can provide a first order approximation of the construction cost of new networks.  One of these tools is the capital cost model developed by Persson &amp; Werner, which is based on, among others, the effective width parameter. This is an indicator of the required trench length in an area supplied by district heating and has been related to the building density.  This work has contributed to the understanding of the effective width parameter in a wide range of building densities, taking advantage of one of the largest district heating networks in Denmark, and provided new equations that relate it to various indicators of building density.  Furthermore, the average pipe diameter of district heating pipes has been linked to another crucial parameter in district heating technology, the linear heat density, extending prior work conducted by Persson and Werner.  In addition, Persson and Werner's model and the newly found empirical expressions have been validated in various Danish district heating networks, showing that the model provides relatively accurate results on an aggregate level and large areas but dismally fails in low-extension areas.  Finally, the model has been applied to the European Union showing that district heating networks could potentially supply a third of the heat demand in 2050. / Lösningen av de pågående klimat- och energikriserna kräver en radikal omvandling av energisystemet, där hållbarhet, inga koldioxidutsläpp och energieffektivitet bör spela en avgörande roll. Denna revolution bör sträcka sig till alla delar av energisystemet, inklusive sektorn för uppvärmning och kylning av byggnader, som står för en tredjedel av Europas slutliga energibehov och på den europeiska kontinenten fortfarande till största delen försörjs av fossila bränslen. Fjärrvärme är en enkel men kraftfull teknik som kan bidra till denna utmaning. Som nätverksinfrastruktur kännetecknas den av flexibilitet i värmeproduktionen, vilket möjliggör inkorporering av ett brett utbud av värmekällor över tid. Dessutom möjliggör det återvinning av värme som annars skulle gå till spillo och användning av lokala värmekällor på ett mer kostnadseffektivt sätt. Dessutom kan dess koppling till elsektorn underlätta ökningen av intermittenta elektriska förnybara energikällor. Detta till trots täcker fjärrvärme för närvarande bara en tiondel av det europeiska behovet av uppvärmning och kylning av byggnader, om än med betydande skillnader mellan länderna. Utbyggnaden av nya fjärrvärmenät är dessutom kapitalkrävande och kan endast motiveras i de områden där koncentrationen av värmebehovet är tillräckligt hög för att ge en lägre kostnad för samhället än ett individuellt alternativ. Därför är det avgörande att bedöma potentialen för fjärrvärme och att identifiera målområdena för fördjupade utredningar. Denna nödvändighet kräver enkla och okomplicerade verktyg, som kan ge en första ordningens uppskattning av investeringskostnader för nya nätverk. Ett av dessa verktyg är kapitalkostnadsmodellen utvecklad av Persson &amp; Werner, som bygger på bland annat parametern effektiv bredd. Detta är en indikator på den erforderliga dikeslängden i ett område som försörjs av fjärrvärme och har relaterats till byggnadstätheten. Detta arbete har bidragit till förståelsen av effektiv bredd-parametern i ett vitt spektrum av byggnadstätheter, vars studium drar fördel av ett av de största fjärrvärmenäten i Danmark, och har gett nya ekvationer som relaterar den till olika indikatorer på byggnadstäthet. Vidare har den genomsnittliga rördiametern för fjärrvärmerör kopplats till en annan avgörande parameter inom fjärrvärmetekniken, den linjära värmedensiteten, vilket utökar tidigare arbete utfört av Persson och Werner. Dessutom har Persson och Werners modell och de nyfunna empiriska uttrycken validerats i olika danska fjärrvärmenät, vilket visar att modellen ger relativt exakta resultat på aggregerad nivå och stora ytor men mindre så i lågutbyggnadsområden. Slutligen har modellen tillämpats på EU som visar att fjärrvärmenät potentiellt kan tillgodose en tredjedel av värmebehovet år 2050. / Quantification of synergies between Energy Efficiency first principle and renewable energy systems

The emergence of silicon-carbide (SiC) devices has been a 'game changer' in the field of power electronics. With desirable material properties such as low-loss characteristics, high blocking voltage, and high junction temperature operation, they are expected to drastically increase the power density of power electronics systems. Recent state-of-the-art designs show the power density over 17 ; however, certain factors limit the power density to increase beyond this limit. In this dissertation, three key factors are selected to increase the power density of SiC-based grid-connected three-phase converters. Throughout this dissertation, the techniques and strategies to increase the power density of SiC three-phase converters were investigated. Firstly, a magnetic integration method was introduced for the coupled inductors in the interleaved three-phase converters. Due to limited current-capacity compared to the silicon insulated-gate bipolar transistors (Si-IGBTs), discrete SiC devices or SiC modules, operate in parallel to handle a large current. When three-phase inverters are paralleled, interleaving can be used, and coupled inductors are employed to limit the circulating current. In Chapter 2, the conventional integration method was extended to integrate three coupled inductors into two; one for differential-mode circulating current and the other for common-mode circulating current. By comparing with prior research work, a 20% reduction in size and weight is demonstrated. From Chapter 3 to Chapter 5, a full-SiC uninterruptible power supply (UPS) was investigated. With the high switching frequency and fast switching dynamics of SiC devices, strategies on electromagnetic inference become more important, compared to Si-IGBT based inverters. Chapter 3 focuses on a common-mode equivalent circuit model for a topology and pulse width modulation (PWM) scheme selection, to set a noise mitigation strategy in the design phase. A three terminal common-mode electromagnetic interference (EMI) model is proposed, which predicts the impact of the dc-dc stage and a large battery-rack on the output CM noise. Based on the model, severe deterioration of noise by the dc-dc stage and battery-rack can be predicted. Special attention was paid on the selection of the dc-dc stage's topology and the PWM scheme to minimize the impact. With the mitigation strategy, a maximum 16 dB reduction on CM EMI can be achieved for a wide frequency range. In Chapter 4, an active PWM scheme for a full-SiC three-level back-to-back converter was proposed. The PWM scheme targets the size reduction of two key components: dc-link capacitors and a common-mode EMI filter. The increase in switching frequency calls for a large common-mode EMI filter, and dc-link capacitors in the three-level topology may take a considerable portion in the total volume. To reduce the common-mode noise emission, different combinations of the voltage vectors are investigated to generate center-aligned single pulse common-mode voltage. By such an alignment of common-mode voltage with different vector combinations, noise cancellation between the rectifier and the inverter can be maximally utilized, while the balancing of neutral point voltage can be achieved by the transition between the combinations. Also, to reduce the size of the dc-link capacitor for the three-level back-to-back converter, a compensation algorithm for neutral point voltage unbalance was developed for both differential-mode voltage and the common-mode voltage of the ac-ac stage. The experimental results show a 4 dB reduction on CM EMI, which leads to a 30% reduction on the required CM inductance value. When a 10% variation of neutral point voltage can be handled, the dc-link capacitance can be reduced by 56%. In Chapter 5, a 20 kW full-SiC UPS prototype was built to demonstrate a possible size-reduction with the proposed PWM scheme, as well as a selection of topologies and PWM schemes based on the model. The power density and efficiency are compared with the state-of-the-art Si-IGBT based UPSs. Chapter 6 seeks to improve power density by a change in a modulation method. Triangular conduction mode (TCM) operation of the three-level full-SiC inverter was investigated. The switching loss of SiC devices is reported to be concentrated on the turn-on instant. With zero-voltage turn-on of all switches, the switching frequency of a three-level three-phase SiC inverter can be drastically increased, compared to the hard-switching operation. This contributes to the size-reduction of the filter inductors and EMI filters. Based on the design to achieve a 99% peak efficiency, a comparison was made with a full-SiC three-level inverter, operating in continuous conduction mode (CCM), to verify the benefit of the soft switching scheme on the power density. A design procedure for an LCL filter of paralleled TCM inverters was developed. With 3.5 times high switching frequency, the total weight of the filter stage of the TCM inverter can be reduced by 15%, compared to that of the CCM inverter. Throughout this dissertation, techniques for size reduction of key components are introduced, including coupled inductors in parallel inverters, an EMI filter, dc-link capacitors, and the main boost inductor. From Chapter 2 to 5, the physical size or required value of these key components could be reduced by 20% to 56% by different schemes such as magnetic integration, EMI mitigation strategy through modeling, and an active PWM scheme. An optimization result for a full-SiC UPS showed a 40% decrease in the total volume, compared to the state-of-the-art Si-IGBT solution. Soft-switching modulation for SiC-based three-phase inverters can bring a significant increase in the switching frequency and has the potential to enhance power-density notably. A three-level three-phase full-SiC 40 kW PV inverter with TCM operation contributed to a 15% reduction on the filter weight. / Doctor of Philosophy / The power density of a power electronics system is regarded as an indicator of technological advances. The higher the power density of the power supply, the more power it can generate with the given volume and weight. The size requirement on power electronics has been driven towards tighter limits, as the dependency on electric energy increases with the electrification of transportation and the emergence of grid-connected renewable energy sources. However, the efficiency of a power electronics system is an essential factor and is regarded as a trade-off with the power density. The size of power electronics systems is largely impacted by its magnetic components for filtering, as well as its cooling system, such as a heatsink. Once the switching frequency of power semiconductors is increased to lower the burden on filtering, more loss is generated from filters and semiconductors, thus enlarging the size of the cooling system. Therefore, considering the efficiency has to be maintained at a reasonable value, the power density of Si-based converters appears to be saturated. With the emergence of wide-bandgap devices such as silicon carbide (SiC) or gallium nitride (GaN), the switching frequency of power devices can be significantly increased. This is a result of superior material properties, compared to Si-based power semiconductors. For grid-connected applications, SiC devices are adopted, due to the limitations of voltage ratings in GaN devices. Before commercial SiC devices were available, the power density of SiC- based three-phase inverters was expected to go over 20 𝑘𝑊 𝑑𝑚3 ⁄ . However, the state-of-the art designs shows the power density around 3 ~ 4 𝑘𝑊 𝑑𝑚3 ⁄ , and at most 17 𝑘𝑊 𝑑𝑚3 ⁄ . The SiC devices could increase the power density, but they have not reached the level expected. The adoption of SiC devices with faster switching was not a panacea for power density improvement. This dissertation starts with an analysis of the factors that prevent power density improvement of SiC-based, grid-connected, three-phase inverters. Three factors were identified: a limited increase in the switching frequency, large high-frequency noise generation to be filtered, and smaller but still significant magnetic components. Using a generic design procedure for three-phase inverters, each chapter seeks to frame a strategy and develop techniques to enhance the power density. For smaller magnetic components, a magnetic integration scheme is proposed for paralleled ac-dc converters. To reduce the size of the noise filter, an accurate modeling approach was taken to predict the noise phenomena during the design phase. Also, a modulation scheme to minimize the noise generation of the ac-ac stage is proposed. The validity of the proposed technique was verified by a full-SiC three-phase uninterruptible power supply with optimized hardware design. Lastly, the benefit of soft-switching modulation, which leads to a significant increase in switching frequency, was analyzed. The hardware optimization procedure was developed and compared to hard-switched three-phase inverters.