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Development of Methods for Phase System Characterization in Liquid ChromatographySamuelsson, Jörgen January 2008 (has links)
The aim of this thesis is first and foremost to improve the fundamental knowledge of nonlinear and preparative separation theory by focusing on some of the remaining “white spots” on the theoretical chromatographic map. Secondly, the acquired knowledge is used to develop, validate and execute new methods for phase characterization in liquid chromatography. The methodology used in this thesis is a combination of experiments, fundamental nonlinear theory and systematic computer simulations. A fundamental knowledge of the molecular interactions between the compounds to be separated and the separation media requires the determination of adsorption isotherms over a broad concentration range to give a complete picture of all interactions in the separation system - weak as well as strong. In addition, such adsorption data is essential for optimization in preparative chromatography. For the first time, it has been experimentally shown that the injected molecules are not present in the detected peak when a small excess of molecules are injected into a chromatographic system equilibrated with a constant stream of identical molecules. Several experimental procedures for this method were developed such as (i) the optimal injection strategy and (ii) different labeling methods for visualizing the injected molecules. Remarkable phenomena in the single-component case, such as invisible peak deformation and deformed (invisible) frontal chromatograms, are reported, investigated, and explained. This phenomenon has asides from its future practical implementation, also a large didactic value. The accuracy of the ECP method is experimentally improved, and used to characterize the separation of protolytic compounds at different pH on modern commercially available silica and hybrid silica column packing materials. That investigation enables us to answer why basic compounds give a much more compact preparative peak profile at pH 11 than they yields at lower pH.
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Domestic Heating with Solar Thermal : Studies of Technology in a Social Context and Social Components in Technical StudiesLundh, Magdalena January 2009 (has links)
Research in solar heating has traditionally focused solely on increasing the system efficiency by improving the technical components. In this thesis the technical methodology and system boundaries are widened to connect the technical aspects with market actors that are highly influential on the implementation of solar technology. The research was focused on how social aspects can be brought into technical studies to improve the understanding of solar heating, and how solar thermal technology can be optimized in a larger energy system. Both heat storage and different system solutions have been investigated. The thesis is built on a number of sub-projects exploring different aspects of solar heating. Improved components and system configurations may result in higher fractional energy savings and thereby make solar energy go from a marginal contribution to be the main energy supplier. Both components and systems are considered in this thesis. The solar heating technology has been shown to work well, also in unique system solutions. Technical possibilities with medium-sized stores for single-family houses and seasonal stores for residential areas are presented. Methods to bring studies of technology and actor studies together are also proposed; domestic hot water use has been modelled based on time-use data, while a multifaceted market situation, in which new system solutions must find their way, has been described by the solar and pellet industries. The complexity of assessing installation and use of a particular heating system in relation to the overall energy system is also discussed. Overall, this thesis shows that successful use of solar heating does not only come down to proper technical solutions, but also depends on the interaction between technology and market actors. A widened perspective, including the social context in which the heating system appears, is then essential. This thesis constitutes a step in that direction.
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Thermal formation and chlorination of dioxins and dioxin-like compoundsJansson, Stina January 2008 (has links)
This thesis contributes to an increased understanding of the formation of dioxins and dioxin-like compounds in combustion processes. Although emissions to air from waste incineration facilities have been greatly reduced by the use of efficient air pollution control measures, the resulting residues (ashes and filters) are highly toxic and are classified as hazardous waste. The main objective of the work underlying this thesis was to elucidate the formation and chlorination pathways of dioxins and dioxin-like compounds in waste combustion flue gases in the temperature range 640-200°C in a representative, well-controlled laboratory-scale reactor using artificial municipal solid waste. This could contribute to the reduction of harmful emissions to air and also reduce the toxicity of waste incineration residues, thus reducing or even eliminating the need for costly and potentially hazardous after-treatment. A comparison of four different quenching profiles showed that the formation of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) was rapid and mainly occurred in the 640-400°C temperature region, with high dependency on sufficient residence time within a specific temperature region. Prolonged residence time at high temperatures (450/460°C) reduced the PCDD yields, even at lower temperatures along the post-combustion zone. PCDD, PCDF and PCN (polychlorinated naphthalene) isomer distribution patterns indicated contributions from chlorophenol condensation as well as chlorination reactions for all three classes of compounds. The formation of PCDDs was largely influenced by chlorophenol condensation and to some extent by chlorination reactions. For the PCDFs, chlorine substitution adjacent to the oxygen bridges was unfavoured, as demonstrated by the notably lower abundance of 1,9-substituted congeners. This was supported by bidirectional orthogonal partial least squares (O2PLS) modelling. The variable with the greatest influence on the distribution of PCDD congeners was the relative free energy (RΔGf). The O2PLS models displayed distinct clusters, dividing most of the homologues into two or three sub-groups of congeners which seemed to correspond to the probability of origination from chlorophenol condensation. The effects of injection of aromatic structures into the flue gas differed for each class of compounds. Injection of naphthalene increased the formation of monochlorinated naphthalene but the remaining homologues appeared to be unaffected. This was probably due to insufficient residence time at temperatures necessary for further chlorination. Injected dibenzo-p-dioxin was decomposed, chlorinated and re-condensated into PCDDs and PCDFs, whereas injection of dibenzofuran and fluorene reduced the PCDD levels in the flue gas. / Denna avhandling fokuserar på olika aspekter som kan bidra till en ökad förståelse av bildning av dioxiner och dioxin-lika föreningar i förbränningsprocesser. Även om utsläppen till luft från sopförbränningsanläggningar har minskat kraftigt tack vare effektiva rökgasreningsmetoder, så återstår problemet med mycket giftiga rökgasreningsprodukter (askor och filter), vilka klassificeras som farligt avfall. Det huvudsakliga syftet med arbetet bakom denna avhandling var att klarlägga bildnings- och kloreringsvägarna för dioxiner och dioxin-lika föreningar i temperaturintervallet 640-200°C i rökgaser från sopförbränning. Detta kan möjliggöra lösningar för ytterligare emissionsminskningar och en avgiftning av biprodukterna från avfallsförbränning, vilket minskar eller till och med eliminerar behovet av kostsam och riskfylld efterbehandling. Realistiska och välkontrollerade försök har utförts i en lab-skalereaktor där en artificiell hushållssopa har förbränts. En jämförelse av fyra olika temperatur- och uppehållstidsprofiler visade att bildning av polyklorerade dibenso-p-dioxiner (PCDD) och dibensofuraner (PCDF) sker snabbt och huvudsakligen inom temperaturintervallet 640-400°C. Bildningen var starkt beroende av en tillräckligt lång uppehållstid inom ett visst temperaturområde. En förlängd uppehållstid vid höga temperaturer (>450°C) resulterade i minskade halter av PCDD, vilka förhöll sig låga även senare i efterförbränningszonen. Isomermönstren av PCDD, PCDF och PCN (polyklorerade naftalener) visade alla tecken på att härröra från både klorfenolkondensation och kloreringsreaktioner. PCDD-mönstret visade tydliga indikationer på bildning från klorfenoler, och till mindre grad bildning via klorering. För PCDF var klorsubstitution i positioner angränsande till syrebryggan missgynnad, vilket bekräftades av multivariat modellering (O2PLS). Den variabel som starkast påverkade bildningen av PCDD var relativa fria energin (RΔGf). Modellerna visade på en distinkt gruppering av PCDD- och PCDF-kongenerna i två eller tre grupper för varje kloreringsgrad, och föreslås vara relaterad till sannolikheten för respektive kongen att bildas via klorfenolkondensation. Injektion av aromatiska kolstrukturer i rökgaskanalen gav upphov till skilda effekter. Injektion av naftalen ökade bildningen av monoklorerad naftalen medan resterande homologer inte verkade påverkas, sannolikt på grund av för kort uppehållstid för ytterligare klorering. Dibenso-p-dioxin spjälkades sannolikt till fenoliska fragment som klorerades och sedan återkondenserades till PCDD och PCDF, medan dibensofuran och fluoren kraftigt reducerade PCDD-koncentrationerna.
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GOAL ORIENTATION PROFILES AMONG YOUNG SOCCER PLAYERS’ IN RELATION TO THEIR USE OF PSYCHOLOGICAL SKILLSroness, simon, madsen, erik January 2011 (has links)
To further investigate athletes’ goal orientations in relation to their use of psychological skills, the present study examined the following objectives: 1) the goal orientations of young Swedish soccer players, (2) their use of psychological skills in both practice and competition and (3) the relationship between their goal orientations and use of psychological skills. Participants were 171 young soccer players from five Swedish high schools. The Perceptions of Success Questionnaire and the Test of Performance Strategies were administered to meet the objectives. Results showed no significant difference between athletes’ task (3.40 ± 1.32; M ± SD) and ego (3.32 ± 1.18) goal orientations. Results further revealed that athletes used more psychological skills in association with competition (3.21 ± .67) than in practice (2.74 ± .63). Moreover, results showed that athletes low in ego orientation used more psychological skills (3.83 ± .67) in practice than athletes high in ego (2.68 ± .60). A recommendation for coaches is to emphasize the importance of using PST in relation to practice in order to maximize athletes’ performances. Results have been discussed in relation to previous research of achievement motivation and athletes’ use of psychological skills.
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Depth Profiles of Radiocarbon and Carbon Isotopic Compositions of Organic Matter and CO_2 in a Japanese Forest Area((2)Summaries of Research Using AMS)劉, 衛, LIU, Wei, 森泉, 純, MORIIZUMI, Jun, 山澤, 弘実, YAMAZAWA, Hiromi, 飯田, 孝夫, IIDA, Takao 03 1900 (has links)
タンデトロン加速器質量分析計業績報告 Summaries of Researches Using AMS 2005 (平成17)年度
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Non-Invasive Microwave HyperthermiaHabash, Riadh W Y 04 1900 (has links)
Presented in this thesis are the following theoretical investigations carried out on the non-invasive microwave hyperthermia of malignant tumours in the human body:
Fundamental concepts of electromagnetic wave propagation through a biomass and its interaction with it, are discussed. Various types of applicators used for producing hyperthermia in a biomass, are also discussed.
Propagation of a uniform plane electromagnetic wave through a human body is investigated for the general case of oblique incidence. Various models used for the human body have been discussed and the planar multilayer model has been chosen for this study. Reflection and transmission coefficients for both the parallel and perpendicular linear polarisations of the wave, have been determined. For normal incidence, power transfer ratio at the muscle has been defined and calculated at 433, 915 and 2450 MHz (ISM frequencies).
Efects of skin thickness and also of fat thickness, on the power transfer ratio at muscle, have been studied. Effects of the thickness and dielectric constant of a bolus, and also of the dielectric constant of an initial layer, on the power transfer ratio, have been studied and their optimum values obtained at the ISM frequencies. For microwave hyperthermia, 915 MHz is recommended as the frequency of operation.
Steady-state solution of the bioheat transfer equation has been obtained, assuming the biomass to be a semi-infinite homogeneous medium. Effects of various physical parameters on the temperature profile in the biomass, have been studied. Also studied is the effect of the surface temperature on the magnitude, location and the width of the temperature peak attained in the biomass. A method to determine the microwave power and the surface temperature required to produce a prescribed temperature profile in the biomass, has been developed. The transient-state solution of the bioheat transfer equation has been obtained to study the building up of the temperature profile.
Procedures for the design of an open-ended rectangular metal waveguide applicator and for estimating the total microwave power requirement to produce hyperthermia in the human body, have been developed. Performance of the applicators employing linear as well as planar arrays of open-ended rectangular metal waveguide antennas, has also been studied. In order to reduce the overall physical size of the applicators, filling up of the feed waveguide with a high dielectric constant but low loss material is suggested. A simple method of obtaining the elements of the array by partitioning a large aperture by using metal walls has been adopted. Calculation of the total microwave power required by various applicators for producing hyperthermia at various depths in a biomas, have been made and a comparison of the performance of various applicators, has been presented.
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”På Facebook slipper man vara närvarande” : En studie kring unga vuxnas syn på användande, identitetsskapande och kvarlämnade digitala identiteter på Facebook / “On Facebook you don’t have to be present” : A study on young adults view upon digital identities and death on FacebookMichael, Carlsson, Lahdensuo, Jonna January 2009 (has links)
<p><strong>Bakgrund:</strong> Facebook är ett socialt onlinenätverk som under sina levnadsår har ökat explosionsartat i popularitet. På Facebook sköter många användare stora delar av sina sociala relationer och delar med sig mycket av sig själva. Det finns inget tidigare socialt nätverk i stil med Facebook som har haft samma genomslagskraft hos internetanvändarna. I användandet skapas en digital identitet som lämnar spår på Facebook, även om en användare är död. Kring dessa kvalämnade digitala identiteter vill vi undersöka unga vuxnas syn.</p><p> </p><p><strong>Syfte: </strong>Vårt syfte med denna uppsats är att ta reda på hur unga vuxna ser på sitt och andras användande av Facebook kopplat till digitala spår och döden.</p><p> </p><p><strong>Metod:</strong> Vi har valt att använda fokusgruppssamtal som metod för insamling av det empiriska materialet. Denna metod är både kvalitativ och induktiv. Det empiriska materialet har vi analyserat med den symboliska interaktionismen som metodologisk ansats.</p><p> </p><p><strong>Resultat: </strong>Det finns många meningsskillnader i vårt resultat. Deltagarna i fokusgrupperna ser både styrkor och svagheter med mediet Facebook då det kommer till döden. Detta handlar i mångt och mycket om att deltagarna ser Facebook som ofullständigt i detta avseende.</p> / <p><strong>Background:</strong> Facebook is a social online network that has expanded in popularity during the course of its existence. Many users manage large parts of their social life and share much information about themselves on Facebook. There is no previous social online network like Facebook, that has had the same development among the internet users. In the use of Facebook users create digital identities, which leave traces on Facebook, even if the user is dead. With this as an aspect, we want to study young adults’ views on digital identities and death on Facebook.</p><p> </p><p><strong>Purpose:</strong> Our purpose in this study is to find out how young adults view upon their own as well as others use of Facebook related to digital traces and death.</p><p> </p><p><strong>Method:</strong> We chose to use focus group as a method of collecting the empirical material. This method is both qualitative and inductive. The empirical material is analyzed with the symbolic interaction as a methodological approach.</p><p> </p><p><strong>Conclusion:</strong> There are many different opinions in our results. The participants in the focus groups see both strengths and weaknesses of the medium Facebook when it comes to death and digital traces. This based on the participants view of Facebook as incomplete medium in this aspect.</p>
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Computational Modeling of Biological Membrane and Interface DynamicsLindahl, Erik January 2001 (has links)
No description available.
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Zur Geochemie ausgewählter Bodenformen im Erzgebirge und Vogtland / The geochemistry of characteristic soil types of the Erzgebirge and Vogtland Regions (Saxony)Metzner, Ines 02 February 2011 (has links) (PDF)
Die geochemischen Verhältnisse der Böden des Erzgebirge und Vogtlandes werden auf der Grundlage der komplexen geochemischen Analyse von ausgewählten, flächenrepräsentativen Bodenprofilen auf Hauptgesteinen des Untersuchungegebietes charakterisiert.
Die Wirkungsweisen vorhandener Einflussfaktoren (Gesteinschemismus, Bodengenese, Bodennutzung) werden untersucht und bewertet.
Die Untersuchungen stellen eine Grundlage für die Ableitung von geologisch bedingten regionalen Hintergrundbelastungen dar. / A characterization of the soil geochemistry of the Erzgebirge and Vogtland Regions (Saxony) is provided on the basis of the investigation of characteristic soil profiles on major bedrock types of the area.
Different factors of influence (rock geochemistry, soil formation, land utilization) are investigated and evaluated.
The investigation provides essential information for the development of regional background concentrations.
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Natural and Anthropogenic Influences on the Morphodynamics of Sandy and Mixed Sand and Gravel BeachesRoberts, Tiffany 01 January 2012 (has links)
Beaches and coastal environments are dynamic, constantly shaped and reshaped by natural processes and anthropogenic modifications. The morphodynamics and influence of natural and anthropogenic factors of two different coasts at various temporal and spatial scales are discussed.
To quantify the performance of several beach nourishment projects at annual temporal and kilometer spatial scales on three adjacent microtidal low-wave energy barrier islands in west-central Florida, a total of 5,200 beach and nearshore-profiles spaced at 300 m were surveyed monthly to bi-monthly from 2006-2010. Beach nourishment performance is most significantly influenced by the interruption of longshore sediment transport by complex tidal-inlet processes. More specifically, the tidal-inlet processes influencing adjacent beach nourishment performance includes longshore transport interruption resulting from divergence induced by wave refraction over an ebb-tidal shoal, flood-tidal currents along the beach, and total littoral blockage by structured inlets. A morphologic indicator of a large longshore transport gradient within the study area is the absence of a nearshore sandbar. These non-barred beaches are characterized by persistent shoreline erosion and were almost exclusively located in areas with a large longshore transport gradient. The more typical beach state along the three barrier islands was one exhibiting a migratory bar and relatively stable shoreline. The presence of a sandbar indicates the dominance of cross-shore processes, with onshore migration during calm wave conditions and offshore migration during energetic wave conditions. The onshore and offshore migration of the sandbar is closely related to non-stormy summer and stormy winter seasonal beach changes, respectively.
The morphodynamics of a mixed sand and gravel beach in Delaware were investigated based on 740 beach profiles surveyed almost monthly from 2009 to 2011, 60 sediment cores, and 550 surface sediment samples collected at various alongshore and cross-shore transects. Inter-seasonal temporal scales of storm-induced beach changes and post-storm recovery were examined based on a hurricane, a typical energetic winter storm, and an extremely energetic storm resulting from the rare collision of a hurricane and winter storm ("Nor'Ida") occurring within a 3-month period in 2009. The mixed sand and gravel beaches in Delaware are characterized by monotonically increasing water depths lacking a sandbar under all wave conditions. A distinctive beach cycle was identified consisting of a built-up berm profile and depleted nearly-planar storm profile, with a time-scale related to the frequency and intensity of storm impact and duration of intra-storm recovery instead of simple seasonality. The sedimentological characteristics of the storm deposit associated with Nor'Ida demonstrated substantial cross-shore variation ranging from sandy-gravel and gravelly-sand within the storm swash zone (near the pre-storm dune edge) to well-sorted medium to coarse sand seaward of the storm swash zone, suggesting that storm deposits along mixed beaches demonstrate a variety of sedimentological characteristics. A new dynamic beach cycle model is proposed for the non-barred mixed sand and gravel beach with temporal variability controlled by storm occurrence and inter-storm duration.
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