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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Curva diária e valores da pressão intraocular obtidos com tonômetro de rebote em equinos hígidos da raça crioula (Equus caballus)

Bacchin, Angela Beatriz de Oliveira January 2018 (has links)
A tonometria é de extrema importância durante o exame oftálmico, pois auxilia no diagnóstico e no acompanhamento do glaucoma e de inflamações intraoculares. No entanto, os valores da pressão intraocular podem sofrer influência do momento do dia em que o exame é realizado. Objetivou-se avaliar a pressão intraocular (PIO) com tonômetro de rebote em equinos hígidos da raça Crioula em diferentes horários do dia. Foram avaliados ambos os olhos de 25 cavalos da raça Crioula, machos ou fêmeas, subdivididos em três categorias de diferentes idades designadas por GI: nove animais (3-5 anos de idade), GII: oito animais (6-8 anos de idade) e GIII: oito animais (9-16 anos de idade). Previamente à tonometria foram realizados teste lacrimal de Schirmer, biomicroscopia com lâmpada de fenda, prova da fluoresceína e oftalmoscopia indireta em todos os equinos. Num mesmo dia foram realizadas sete aferições da PIO (às 6, 9, 12, 15, 18, 21 e 24 horas). A avaliação estatística utilizou o teste T de Student quando haviam dois grupos de comparações, e o teste de análise de variância (ANOVA) para as variáveis PIO, horário de aferição (tempo) e categoria de idade. O valor médio da pressão intraocular obtido foi de 28,4±3,7 mmHg considerando todos os animais avaliados. Os valores médios da pressão intraocular para os equinos de GI, GII e GIII foram 29,2±3,5 mmHg, 28,4±4,3 mmHg e 27,7±3,2 mmHg, respectivamente. Não houve diferença estatisticamente significativa entre os olhos direito e esquerdo (p= 0,257), nem entre sexos (p= 0,284). Quando comparadas as idades, a PIO média foi significativamente maior nos indivíduos jovens (p= 0,012). Não houve diferença estatisticamente significativa entre os diferentes horários do dia (p= 0,560). Os valores da PIO aferidos com o tonômetro de rebote em equinos da raça Crioula sofreram influência da idade. Os valores da pressão intraocular média obtidos com tonômetro de rebote em equinos hígidos não variaram em diferentes horários ao longo do dia. / The tonometry is extremely important during ophthalmic examination, because assists in the diagnosis and follow-up of glaucoma and intraocular inflammation. However, intraocular pressure values may be influenced by the moment of the day it is measured. The objective was to evaluate the intraocular pressure (IOP) with Rebound Tonometer in healthy horses of the Crioula breed at different times of the day. Twenty five horses, male or female, were divided into three groups by age: Group I: nine horses (3-5 years old), Group II: eight horses (6-8 years old), and Group III: eight horses (9-16 years old). Ophthalmic examination was performed previously by Schirmer Tear Test, slit lamp biomicroscopy, fluorescein test and indirect ophthalmoscopy in all horses. Seven measurements of intraocular pressure were assessed on the same day (at 6, 9, 12, 15, 18, 21 and 24 hours).The Student’s T Test statistical analysis was used when there was two groups of comparisons, and the Analysis of Variance (ANOVA) was used for variables IOP, measurement time and age category. The average value of intraocular pressure was 28.4 ± 3.7 mmHg considering all the animals evaluated. The mean intraocular pressure for groups I, II and III were 29.2 ± 3.5 mmHg, 28.4 ± 4.3 mmHg and 27.7 ± 3.2 mmHg, respectively. There was no statistically significant difference between right and left eyes (p = 0.257), nor between genders (p = 0.284). When compared to the ages, the average IOP was significantly higher in young animals (p = 0.012). There was no statistically significant result between the different times of the day (p = 0.560). The IOP values measured with rebound tonometer in Crioula horses were influenced by age. The average intraocular pressure values obtained with rebound tonometer in healthy horses did not change with time of day.
32

Simple Question, Complex Answer : Pathways Towards a 50% Decrease in Building Energy Use

Weiss, Philipp January 2014 (has links)
Addressing building energy use is a pressing issue for building sector decision makers across Europe. In Sweden, some regions have adopted a target of reducing energy use in buildings by 50% until 2050. However, building codes currently do not support as ambitious objectives as these, and novel approaches to addressing energy use in buildings from a regional perspective are called for. The purpose of this licentiate thesis was to provide a deeper understanding of most relevant issues with regard to energy use in buildings from a broad perspective and to suggest pathways towards reaching the long-term savings objective. Current trends in building sector structure and energy use point to detached houses constructed before 1981 playing a key role in the energy transition, especially in the rural areas of Sweden. In the Swedish county of Dalarna, which was used as a study area in this thesis, these houses account for almost 70% of the residential heating demand. Building energy simulations of eight sample houses from county show that there is considerable techno-economic potential for energy savings in these houses, but not quite enough to reach the 50% savings objective. Two case studies from rural Sweden show that savings well beyond 50% are achievable, both when access to capital and use of high technology are granted and when they are not. However, on a broader scale both direct and indirect rebound effects will have to be expected, which calls for more refined approaches to energy savings. Furthermore, research has shown that the techno-economic potential is in fact never realised, not even in the most well-designed intervention programmes, due to the inherent complexity of human behaviour with respect to energy use. This is not taken account of in neither current nor previous Swedish energy use legislation. Therefore an approach that considers the technical prerequisites, economic aspects and the perspective of the many home owners, based on Community-Based Social Marketing methodology, is suggested as a way forward towards reaching the energy savings target.
33

Non-Destructive Testing Of Concrete Bridges

Hedlund, Nadja January 2020 (has links)
Non-destructive testing is of great value in cases where a structure's future is investigated to find out what the best measure is. It is not always the best solution to demolish and build new. Many structures can be repaired and function several more years. In this thesis the main goal is to investigate some different non-destructive techniques and learn more about difficulties and strengths. The test subjects will be a cast T-beam in a laboratory environment as well as a case study of a railway bridge in Abisko.   The different testing equipment being used in this thesis is a covermeter, a rebound hammer and ultrasonic pulse velocity. For both the T-beam and the bridge the results are overall very good. The covermeter is proven to be both easy to use and very reliable and the ultrasonic pulse velocity was more to learn about and more difficult but is giving very good results as well.   Conclusions after the thesis project is that it requires a lot of experience of the user and time to make non-destructive testing useful and competitive in the society. Getting all the pieces together it is a powerful tool that hopefully is a sustainable asset in the future, regarding both economic and environmental issues.
34

Liquid Marbles

Khalil, Kareem 12 1900 (has links)
Granulation, the process of formation of granules from a combination of base powders and binder liquids, has been a subject of research for almost 50 years, studied extensively for its vast applications, primarily to the pharmaceutical industry sector. The principal aim of granulation is to form granules comprised of the active pharmaceutical ingredients (API’s), which have more desirable handling and flowability properties than raw powders. It is also essential to ensure an even distribution of active ingredients within a tablet with the goal of achieving time-controlled release of drugs. Due to the product-specific nature of the industry, however, data is largely empirical [1]. For example, the raw powders used can vary in size by two orders of magnitude with narrow or broad size distributions. The physical properties of the binder liquids can also vary significantly depending on the powder properties and required granule size. Some significant progress has been made to better our understanding of the overall granulation process [1] and it is widely accepted that the initial nucleation / wetting stage, when the binder liquid first wets the powders, is key to the whole process. As such, many experimental studies have been conducted in attempt to elucidate the physics of this first stage [1], with two main mechanisms being observed – classified by Ivenson [1] as the “Traditional description” and the “Modern Approach”. See Figure 1 for a graphical definition of these two mechanisms. Recent studies have focused on the latter approach [1] and a new, exciting development in this field is the Liquid Marble. This interesting formation occurs when a liquid droplet interacts with a hydrophobic (or superhydrophobic) powder. The droplet can become encased in the powder, which essentially provides a protective “shell” or “jacket” for the liquid inside [2]. The liquid inside is then isolated from contact with other solids or liquids and has some fascinating physical properties, which will be described later on. The main potential use for these liquid marbles appears to be for the formation of novel, hollow granules [3], which may have desirable properties in specific pharmaceutical applications (e.g. respiratory devices). They have also been shown to be a highly effectively means of water recovery and potentially as micro-transporters and micro-reactors [4]. However, many studies in the literature are essentially proof-of-concept approaches for applications and a systematic study of the dynamics of the marble formation and the first interactions of the liquid droplet with the powder is lacking. This is the motivation for this research project, where we aim to provide such information from an experimental study of drop impact onto hydrophobic powders with the use of high-speed imaging.
35

What is the role of sustainable consumption in the smart sustainable cites’ projects across Europe?

Echaniz, Oriol Costa January 2014 (has links)
Current projections indicate that by 2050, two in every three people will live in urban areas, and that cities will accommodate 3 billion people during this period. Cities are consuming three-quarters of the world's energy and causing three-quarters of global pollution. To reduce these impacts, new technologies have been considered in the development of smart sustainable cities, but technology has not always favoured the idea of sustainable consumption. To address this issue, we have aimed to focus on identifying the role of sustainable consumption within implementations of smart cities’ projects across Europe. We have selected a set of smart city projects in 76 cities in Europe from CONCERTO initiatives, Mapping Smart Cities in Europe, Energy Study for the Stockholm Region and Joint European Support for Sustainable Investment in City Areas and classified them according to: smart governance, smart mobility, smart living, smart environment, smart citizens and smart economy. Furthermore, we established a number of categories for the classification of the evaluated projects based on their relevance to sustainable consumption, and considered several solutions for the integration of sustainable consumption in smart sustainable cities. The results show that in 18.9% of the projects, sustainable consumption is not relevant at all. The second classification shows the percentage of the remaining categories where sustainable consumption is relevant; 8.3% consider sustainable consumption as relevant even though it was not implemented in the project. These cities aim to achieve a higher level of sustainable consumption, which is expected to be included in future projects. If they keep themselves in this category, their behavioural consumption patterns will not change and the impact of citizens on the cities will remain the same. The majority of the projects, 54.2%, implemented technology to reduce consumption but if the projects do not coincide with the behaviour of citizens, a big rebound effect will occur. 37.5% of the projects consider relevant sustainable consumption to its full potential and this can change citizen’s behaviour. In conclusion, sustainable consumption is relevant in most of the projects analysed, with new technologies available to help energy savings and reduction of our consumption. However, if there is a lack of smart consumption from the citizens, the technologies available might not be sufficient and consumption could increase. One quarter of the analysed smart cities projects still do not consider the consumption behaviour of the citizens. This can be changed through campaigns and explanations targeting the population on how to manage and reduce energy and resource consumption. To reduce the negative impact of the cities’ growth, projects considering smart sustainable cities need to integrate sustainable consumption policies that account for citizens' behaviour.
36

Holocene Lake-Level Change and Submerged Archaeological Site Potential of Rice Lake, Ontario

Sonnenburg, Elizabeth 12 1900 (has links)
<p> Isostatic rebound and climatic changes throughout the Holocene have resulted in several periods of lowered water-levels in the Great Lakes watershed. The Early Holocene lowstand phase corresponds with the Paleoindian period in the Great Lakes Region (11,000-9000 YBP), and subsequent water-level rise has inundated Paleoindian archaeological sites. This research sought to reconstruct the water-level history of Rice Lake (located north of Lake Ontario) in order to identify areas of high potential for submerged prehistoric sites. </p> <p> Over 750 line km of detailed geophysical data (single-beam bathymetry) and 16 sediment cores were collected over a 30 km2 area of Rice Lake. Sediment cores were visually logged and analyzed for particle size, microfossils and microdebitage. Water-level reconstructions accounting for sediment infill and isostatic rebound of the lake record a post Lake Iroquois (after 12 ka BP) Early Holocene lowstand (~10-12 m below present level (bpl)) (EH-1). At 10 ka BP, gradually rising water-levels and establishment of wetlands as indicated by thecamoebian assemblages coincide with a newly discovered Paleoindian occupation of the Mcintyre basin, where quartz microdebitage was found. Waterlevel continued to rise to almost 2 m bpi until 6.5 ka BP, when warmer and drier temperatures caused a sudden drop in water-levels as recorded by a pollen hiatus. After 4 ka BP, water-levels quickly recovered and stabilized as shown by rapid recovery of pre-hiatus thecamoebian biofacies and the establishment of wild rice stands. </p> <p> The small number of known, well-preserved Great Lakes Paleoindian sites has limited analysis of Early Holocene population densities, migration patterns, cultural diffusion, or the chronology of settlement. The method of modelling water-level fluctuations and associated archaeological potential developed in this thesis represents a substantial advance in our understanding of Early Holocene archaeology in the Great Lakes. These methods will have broader application to exploration of submerged terrestrial landscapes elsewhere in the Great Lakes and will allow for future regional synthesis of archaeological site distribution and characteristics. </p> / Thesis / Doctor of Philosophy (PhD)
37

Crustal motion in the Antarctic interior from a decade of global positioning system measurements

Willis, Michael J. 07 January 2008 (has links)
No description available.
38

Numerical simulations of vortices near free and solid surfaces

Luton, J. Alan 05 October 2007 (has links)
The interaction of vortices passing near free and solid surfaces has been examined using direct numerical simulation (DNS). A computer code was developed which solves the unsteady, three-dimensional Navier-Stokes equations for incompressible flow. A critical element of the numerical scheme is the efficient solution of Poisson's equation. A state of the art solver based on multigrid techniques was developed which gives excellent convergence rates. The result is a tool capable of modeling complex three-dimensional flows in a variety of configurations. Three different flow fields have been examined in order to determine some of the complex interactions involved between a vortex and a surface. The first concerns the two-dimensional interaction between a boundary layer and a convecting vortex. The size and height above the wall of the vortex are the same order of magnitude as the boundary layer thickness. A strong primary vortex creates a secondary vortex which causes the rebound of the primary, a response observed in many previous studies. However, weaker vortices as well do not follow the inviscid trajectory despite the absence of a secondary vortex. Rather than creating vorticity at the wall, a weaker vortex mainly redistributes the vorticity of the boundary layer. The redistributed vorticity alters the path of the vortex in ways not seen for vortex/wall interactions. / Ph. D.
39

Protection of buried rigid pipes using geogrid-reinforced soil systems subjected to cyclic loading

Elshesheny, Ahmed, Mohamed, Mostafa H.A., Sheehan, Therese 16 March 2021 (has links)
Yes / The performance of buried rigid pipes underneath geogrid-reinforced soil while applying incrementally increased cyclic loading was assessed using a fully instrumented laboratory rig. The influence of varying two parameters of practical importance was investigated; the pipe burial depth and the number of geogrid-layers. Measurements were taken for pipe deformation, footing settlement, strain in pipe and reinforcing layers, and pressure/soil stress on the pipe crown during various stages of cyclic loading. The research outcomes demonstrated a rapid increase in the rate of deformation of the pipe and the footing, and the rate of generated strain in the pipe and the geogrid-layers during the first 300 cycles. While applying further cycles, those rates were significantly decreased. Increasing the pipe burial depth and number of geogrid-layers resulted in reductions in the footing and the pipe deformations, the pressure on pipe crown, and the pipe strains. Redistribution of stresses, due to the inclusion of reinforcing layers, formed a confined zone surrounding the pipe providing it with additional lateral support. The pipe invert experienced a rebound, which was found to be dependent on pressure around the pipe and the degree of densification of the bedding layer. Data for strains measured in the geogrid-layers showed that despite the applied loading value and the pipe burial depth, the tensile strain in the lower geogrid-layer was usually higher than that measured in the upper layer.
40

Strategic Mitigation of Digital Rebound Effect in Organisations : A study from multiple stakeholder perspectives

Nguyen, Trang Anh, Nsonga Jr., Samuel January 2024 (has links)
Research Background: There is a growing focus on the sustainability implications of digitalisation in research, industry and politics. While digitalisation offers economic benefits and potential environmental solutions, it also brings unintended consequences known as rebound effects. These effects, amplified by the widespread impact of digitalisation on economies and societies, have drawn attention to the need for mitigation strategies. However, current research primarily focuses on defining and studying rebound effects rather than on mitigation. Existing mitigation strategies mainly involve fiscal and policy measures, but alternative approaches that address underlying principles are needed. Further research is crucial for exploring effective strategies to mitigate rebound effects caused by digitalisation.  Research Purpose: This thesis aims to identify mitigation strategies for the digital rebound effect employed by companies by understanding the contributing factors to this complex phenomenon.    Method: A qualitative method was used to investigate strategies for companies to mitigate the digital rebound effect amid digitalisation and sustainability concerns. Through exploratory research, we aimed to comprehensively understand underlying factors, mitigation strategies and associated challenges. Semi-structured remote interviews were chosen for data collection to provide detailed insights. Purposive sampling was employed to identify suitable participants for the research topic. Our analysis and presentation of empirical findings followed an abductive approach.  Conclusion: Our framework, based on Bohnsack et al. (2021) model, delves into the unintended consequences of digital technology by incorporating stakeholder perspectives. Key contributing factors include personal challenges and resource-related issues. Addressing these factors requires fostering a learning culture and technical competence. Mitigation strategies in the thesis focus on the firm and individual levels. Stakeholder involvement is crucial for effective problem-solving. Our framework aligns with stakeholder theory, enhancing understanding and mitigation of digital rebound effects.

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