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110 Uppsatser om Atomic absorption spectrophotometry - Sida 2 av 8
Registreringsmetoder för initial och avancerad dental erosion : Litteraturstudie
Introduktion: Dental erosion definieras som förlust av tandens hårdvävnad genom en kemisk process som inte involverar bakterier. Dagens förändrade livsstil och kosthållning medför att våra tänder oftare utsätts för kemisk påverkan som kan leda till erosion. Det är flera faktorer som samverkar och dental erosion har en multifaktoriell etiologi.Syfte: Syftet är att beskriva olika registreringsmetoder för dental erosion.Frågeställningar: Vilka metoder kan användas för registrering av initial erosion? Vilka metoder kan användas för registrering av avancerad erosionsskada? Vilka metoder är kliniskt beprövade på patient?Metod: LitteraturstudieResultat: Ett flertal registreringsmetoder fanns beskrivna i litteraturen, merparten var inte applicerbara kliniskt. Registeringsmetoderna som framgick i den beskrivande litteraturstudien var: 3D scanning microscope (IFM), Atomic absorption spectroscopy (AAS), Digital photography (DP), Focus-variation 3D microscopy (FVM), Longitudinal microradiography (LMR), Non-contact confocal laser scanning microscopy (CLSM), Optical assessment, Optical profilometry (OP), Quantitative light-induced fluorescence (QLF), Scanning electron microscopy (SEM), Stylus profilometry (SP), Ultrasound, White light interferometry (WLI) och X-ray diffraction (XRD).Konklusion: Vid registrering av initial erosion krävs analys av tandytans mineralinnehåll samt optiska analyser med hjälp av instrument.
Kalcium- och fosforsmältbarhet hos växande hästar
In the latest edition of NRC (2007) the feeding recommendations for Ca and P to growing
horses were increased with 35 and 25 %, respectively, based on results from a Canadian study
showing that daily endogenous fecal losses of Ca and P were greater than previously
suggested. A Ca absorption efficiency of 50 % is used for all horses. However, the true
absorption efficiency might be as high as 70 % in young horses. P absorption efficiency is
assumed to be higher for growing horses because their diets are often supplemented with
inorganic P. Thus, an efficiency of 45 % is used for growing horses as compared to 35 % for
mature horses.
Akustisk design av studiorum för musikinspelning
Detta projekt genomfördes i samarbete med akustikern Erling Nilsson på företaget Ecophon i Hyllinge. Uppdragsgivare var musikproducenten Magnus Ågren som äger studion Flow Music i Malmö. Uppgiften var att förbättra akustiken i ett av Flow Musics studiorum. Rummet hade före projektet en hård och obehaglig akustik. För att komma fram till ett åtgärdsförslag specificerades först hur enskilda akustiska egenskaper skulle påverkas för att ge ett så bra resultat som möjligt.
Double integrating spheres: A method for assessment of optical properties of biological tissues
The determination of the optical properties of biological tissue is an important issue in laser medicine. The optical properties define the tissue´s absorption and scattering behaviour, and can be expressed by quantities such as the albedo, the optical thickness and the anisotropy coefficient. During this project, a measurement system for the determination of the optical properties was built up. The system consists of a double integrating sphere set-up to perform the necessary reflection and transmission measurements, and a computer algorithm to calculate the optical properties from the measured data. This algorithm is called Inverse Adding Doubling method, and is based on a one-dimensional transport model.
Iron bioavailability and pro- and prebiotics
Iron deficiency is one of the most frequent micronutrient deficiencies around the world. Low iron bioavailability simultaneously with a high iron requirement is a high risk factor for developing iron deficiency. Probiotics are microorganisms that confer a health benefit on the host. Prebiotics are oligosaccharides which provide a health benefit on the host due to a positive modulation of the microflora in the gut. The aim of this paper is to evaluate if there is a connection between pro-and/or prebiotics and iron bioavailability.
Akut mikrocystinförgiftning hos däggdjur
Förgiftningar hos däggdjur som druckit vatten kontaminerat med cyanotoxiner har observerats världen över, och riskerar att öka i takt med tilltagande övergödning och klimatförändringar. Denna litteraturstudie inriktar sig på mikrocystin (MC) som är det vanligaste och mest studerade cyanotoxinet. Studien avgränsar sig till akut intoxikation hos däggdjur och fokuserar på grundläggande mekanismer hos toxinet, såsom absorption, distribution, metabolism och elimination. Vidare beskrivs de toxiska mekanismerna och de akuta toxiska effekterna.
MC orsakar utbredda nekroser och blödningar i levern. Den specifika distributionen till levern anses bero på det höga uttrycket av organiska anjontransportörer (OATP).
Granvirkes permeabilitet beroende av dess fysikaliska utformning och applicerat färgsystem
Densitetsmätningar och permeabilitetstest enligt EN 927-5 har utförts för att studera huruvida granvirkes fysikaliska egenskaper i kombination med applicerat färgsystem påverkar permeabiliteten. De egenskaper som studerats är frod- och senvuxenhet, splint- och kärnved samt densitet. Aktuella färgsystem som studerats är alkyd, akrylat och linolja, vilka jämförts med omålad referens. Studien påvisar inget samband mellan virkets densitet och permeabilitet, bestruket eller ej. Det som istället tycks påverka vattenabsorptionen är närvaro av splint-/kärnved samt frod-/senvuxenhet.
Ökad resurseffektivitet i kraftvärmesystem genom säsongslagring av värme
Increased resource efficiency in an energy system could result in large economic and environmental benefits. Tekniska verken i Linköping AB (Tekniska verken) is responsible for the district heating network in Linköping. Their vision is to create the world?s most resource efficient region. An important step towards this vision is more efficient usage of produced heat, something which could be achieved through integration of a seasonal heat storage in the energy system.
Tuftade ljudabsorbenter ? väggpaneler för rumsliga och akustiska egenskaper
It is a well-known fact that textiles and carpets have benign sound-absorbing properties. It is desirable to have quantified values of these properties ? especially for architects and interior designers. They often need to be able to giveaccount for the acoustic properties of their designs at a relatively early stage and sometimes have strict acoustic classifications imposed upon them by their contractor. A product with documented acoustic properties would aid when prescribing interior elements.The purpose of this thesis is to develop a wall-mounted panel in hand-tufted material ? aesthetically pleasing and versatile but also having documented and quantified acoustic properties.
Geotermi i Ungern : Undersökning av Ungerns energisituation inriktat på geotermi samt kapacitetsfaktorn för det största geotermiska värmeverket i Mellaneuropa.
Hungary?s share of renewable energy in 2010 was 7.9 %, and their renewable energy goal for 2020 is 14.65 %. Geothermal energy is one option that could help to achieve the goal, since Hungary has favorable bedrock, the temperature gradient is above average and thepermeability is high. Today Hungary is importing just over half of its primary energy supply. Because of political conflicts between nations Hungary wants to expand its own production of energy.
Restvärmeåteranvändning från absorptionsvärmepumpar : en kartläggning av möjligheter och begränsningar vid Vattenfall Värme Uppsala Block 5
Vattenfall district Heating power plant in Uppsala produces district cooling with absorption heat pumps which leads to a large amount of waste heat that has to be cooled with evaporative cooling towers. The Environmental Court has ordered Vattenfall to survey the possibilities to recover the heat, which is the focus of this thesis.The study begins with an overview of the system, and conditions and limitations for waste heat recovery is examined. In the next step alternatives to recycle the heat is evaluated, either by direct recovering or by upgrading.First, the technical possibility of each alternative is discussed, and then the operation time and the amount of recovered heat is calculated. Those alternatives which are possible are brought further to an economic analysis.The cost of investment for each alternative constitutes the basis for a present value analysis. The results are put together in a table where the total amount of recovered heat is compared with the present value for the different alternatives.
Internkommunikation hos en mobiloperatör : ? en studie av motivation och upptagningsförmåga av information hos butikschefer
AbstractTitle: Internal Communication at a large mobile operator (Internkommunikation hos en mobiloperatör - en studie av motivation och upptagningsförmåga av information hos butikschefer)Number of pages: 43Author: Helena IsakssonTutor: Peder Hård af SegerstadCourse: Media and Communication Studies CPeriod: Fall term 2006University: Division of Media and Communication, Department of Information Science, Uppsala University.Purpose/Aim: The purpose of this essay is to gain an insight in how a corporations store managers motivation affects the degree of information they absorb from information channels.Material/Method: The method that had been used in this essay is quantitative. It is based around a questionnaire aimed towards store managers and consequently used it to run regression analysis using the software package SPSS.Main results: The main result of the essay is that the motivation among store managers is positively related to the degree to which they absorb information. Thus, a possible problem exists for the corporation in that they need to make sure that the store managers are and stays motivated. Further, it seems that the longer a store manager has been employed by the corporation the less information is absorbed. The reader should although interpret the results with caution, since the limited sample could bias the estimates.Keywords: Internal communication, organizational communication, motivation, information, information channels and absorption of information..
Pelletering av tallspån : grundläggande studier
Wood pellets are an upgraded product of residuals from several wood processing industries, for example saw mills and pulp industries. The pellets are produced by pressing the milled and dried sawdust to cylindrical units with a higher density than the initial raw material. Pellets have great benefits compared to the raw material: high energy per volume, good transport and storage properties and homogeneity.
Several parameters collaborate in the whole process, which makes it complex. Wood is a heterogeneous material, chemically and structurally dependent on wood parts, habitat and storage procedures.
Effekter av högt kaliumintag på magnesiumbalansen hos mjölkkor :
Magnesium is one of the most important minerals in the body and it participates in many essential processes, such as energy metabolism and protein synthezis. Magnesium deficiency in cattle may occur when they are let out for pasture in the spring, and is associated with tetany, known as grass staggers. A high yielding dairy cow often loses more magnesium daily in the milk than she has available in the body, and magnesium thereby needs to be provided in the feed to prevent the cow from being affected by deficiency symptoms.
The uptake of magnesium is mainly located to the rumen and is not regulated by hormones. The surplus is excreted in the urine by the kidneys.
Kemiskt försvar mot havstulpanskolonisering i marina svampdjur
The purpose of this project is to analyze and study the absorption of the substances ivermectin, spinosad and barettin to hydrophobic and hydrophilic surfaces, and to analyze and study if the barnacle larva are effected when they try to settle on the treated surface.Incubation tests with barnacle larva in Petri dishes were performed as well as absorption tests on hydrophobic and hydrophilic surfaces which were tested with ellipsometry. To determine the surface thickness.The barnacles were placed in hydrophobic as well as hydrophilic Petri dishes that had been incubated with ivermectin, spinosad or barettin. After four to six days the larva was counted to analyze the settling. From the results conclusions could be drawn about the adsorption abilities of the substances to the different surfaces.The barnacles were placed in hydrophobic as well as hydrophilic Petri dishes that had been incubated with ivermectin, spinosad or barettin. After four to six days the larva was counted to analyze the settling.