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118 Uppsatser om Absorption spectra - Sida 1 av 8

Tidsberoende kvantkemiska beräkningar av optisk absorption hos polymerer och molekyler med litet bandgap

The vertical electronic excitation energies for the narrow-bandgap polymers LBPF, EP37 and EP62 have been calculated using Density Functional Theory (DFT). Also the vertical excitation energies for the acceptor unit of LBPF have been calculated using the Hartree-Fock (HF), DFT and Coupled Cluster (CC) methods. The calculations cover the visible and infrared wave length region and two strong transitions are obtained, one corresponding to the pi to pi* transition and one corresponding to the pi to Acceptor transition. The excitation energies obtained from DFT are below the corresponding experimental results and attempts have therefore been made to perform bench-marking calculations using a hierarchy of CC methods..

En studie av elektronisk mobbning : Vilka kunskaper om och erfarenheter av elektronisk mobbning har flickor med språkstörning och autismspektra

The purpose of this study is to analyze the phenomenon of ?electronic bullying?, and furthermore to describe how this phenomenon is perceived by teenage girls with language disorders in combination with autism spectra. The conclusions and result from this study is derived from six in-depth interviews, thereof four being with girls with autism spectra diagnosis and all but one diagnosed with language disorder in addition (referred to as main respondents). The two reminding girls neither had language disorder nor autism spectra (referred to as comparing respondents). They were added to the study for the purpose of comparing their experiences and descriptions of those with language disorder and/or autism spectra diagnosis. For interpretation and analysis of study result, I have applied the method of phenomenology.                              The study?s main respondents had own experiences in the area of electronic bullying, albeit their level of knowledge of the subject were very limited and they had problems to interpret information given.

Fuktegenskaper hos Quartzene impregnerat med salter

Svenska Aerogel AB has developed the material Quartzene® which is of the typeprecipitated silica and contains calcium - magnesium silicate ((Ca, Mg) SiO3). Thematerial is used for molecular filtration of contaminated air. Qartzene?, which is inpellet form, is porous and has a high internal surface which is a requirement for themolecular filtration. With the use of various impregnations, filtration can affect thedesired outcome.

Kyla i Nyköping och Motala : Kartläggning av kylapotential för Vattenfall Värm

The Swedish energy company Vattenfall is currently the owner of the district heatingsystems in Nyköping and Motala. To be able to also offer cooling solutions tocustomers are becoming more and more important. This report describes the resultsof an investigation of the cooling market in the two cities and the potential needs forcooling today and in the coming 20 years. The total potential for the coming 20 yearsis estimated to be roughly 17 MW for Nyköping and 9 MW for Motala.Two possible district cooling systems for each of the two city centers was modeledand a comparison was made between different cooling techniques namely absorptionand compressor chillers.Absorption chillers driven with district heating during the summer is one way ofincreasing the load in a combined heat and power plant and thereby the possibleelectricity generation. The cost of heat production must be low for absorption chillerto be able to compete as an alternative.

Faktorer som påverkar magnesiumabsorptionen i våmmen hos kor

In metabolism Mg plays an important role because it affects many cellular enzymes in the body. The energy metabolism and protein synthesis are dependent on Mg as an enzyme activator, Mg is also involved in the synthesis of RNA and DNA. Absorption of Mg primarily takes place over the ruminal epithelium in ruminants. The main storage of Mg is in the bones but that can only be reached if the cow is in great need of calcium or phosphorus, it's a hormonal regulated process that induces catabolism of bones. Free and available sources of Mg are found in soft tissues and in the extra cellular fluids that includes cerebrospinal fluids and blood.

Akustikavskärmning och absorption

Det här är ett projekt i industriell design som gick ut på att lösa ett problem. Projektet var ett samarbete med kontors- och utbildningsmöbelföretaget Abstracta. Problemet var att det på arbetsplatser idag lätt blir högljutt och bullrigt, speciellt i öppna kontorslösningar. För att ta fram en produkt som löser problemet gjordes undersökningar och analyser av marknaden, kunden, användaren, akustik och material. Det utgjorde grunden för en idégenerering som resulterade i ett koncept, som sedan vidareutvecklades till en serie akustikabsorbenter.

Magnesiumstatus hos mjölkkor : en fältstudie

Magnesium is an essential mineral that is important for several physiologic and biochemical processes in the body. Deficiency of magnesium is mainly associated with grass tetany, but can also appear in cows during the indoor period. Since long it is known that potassium has a negative effect on the absorption of magnesium. Due to the fact that potassium fertilisation leads to a higher potassium content in forage, it is of interest to study interactions of potassium on the magnesium balance in dairy cows. There are few studies about magnesium feeding to dairy cows in Sweden and the purpose of this study was to investigate how much magnesium and from which feed-sources dairy cows in Sweden get their magnesium. Data was collected from seven farms in the northern part of Uppland and from seven farms in Skaraborg in Sweden.

Återfjädring vid bockning av höghållfast stål

Svenska Aerogel AB has developed the material Quartzene® which is of the typeprecipitated silica and contains calcium - magnesium silicate ((Ca, Mg) SiO3). Thematerial is used for molecular filtration of contaminated air. Qartzene?, which is inpellet form, is porous and has a high internal surface which is a requirement for themolecular filtration. With the use of various impregnations, filtration can affect thedesired outcome.

Expansionsmaskiner istället för strypventiler - en effektivisering

In Uppsala CHP Plant, there are six pressure reducing valves to reduce the pressure from 15 to 3 bars, before six absorption heat pumps. During the process the energy is conserved but losses occur in form of exergy. The aim of this thesis is to reduce the losses of exergy. This can be done by letting turbines replace the pressure reducing valves.In this thesis an investigation has been done of the conditions today, the conditions after the change from pressure reducing valves to turbines and a comparison of three different types of turbine solutions. The three examined solutions are one turbine, several helical screw expanders and several small turbines in parallel with asynchronous generators.The six absorption heat pumps have been divided into two groups; one group of four and one group of two absorption heat pumps.

Akrylamid : skillnader i upptag, metabolism och utsöndring mellan gnagare och människa

Acrylamide (AM) is a commonly used monomer in the manufacture of polyacrylamide. In addition, AM has been found in heated foods that are rich in starch. The main dietary sources in Sweden tend to be crisps, French fries, fried potatoes, crisp bread, cookies and coffee. Un-fortunately, dietary intake of AM has in several studies been shown to cause cancer in ro-dents. Consequently, the compound is currently regarded as a potential carcinogen in hu-mans.

Problem med röda hamburgare efter tillagning : bakgrund och möjliga lösningar

Persistent pink in beef patties and hamburgers is a problem in the meat industry that has been known for a few decades. It is a costly problem as it can give rejections of food by consumers. Studies around the world have tried to solve the problem but it still remains a mystery. There are many different theories of what is causing the red colour. Some of the most likly theories are reducing hemocromes, high microbiological loads, contamination of nitrite or organic/non organic substanses, DFD meat etc.

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.

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