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353 Uppsatser om Chemical precipitation - Sida 19 av 24

Syntes av hydroxyapatit/ nanocellulosa kompositer

Cellulose nanocrystals (CNC) are great candidates for composite materials. The reasons why CNCs are such attractive materials for them are due to their great mechanical properties, high aspect ratio and low density. On the other hand, hydroxyapatite (HAp) is a kind of calcium phosphate and a main component of bones and teeth. The purpose of the present study is to make oriented nano-sized composites with CNC and HAp. Although some researchers carried out to make CNC composites with HAp for biomedical materials, nano-sized and oriented ones haven?t been achieved yet.

Hårdhetsvariation i grundvatten längs Badelundaåsen mellan Leksand och Avesta

Water hardness indicates the concentration of calcium and magnesium ions in water. Water with high concentrations of these ions is described as hard water and water with low concentrations is described as soft water. Water that is too hard or too soft can lead to technical and economical problems. In collaboration with Midvatten AB, groundwater hardness in the Badelunda esker between Leksand and Avesta has been mapped, and an attempt has been made to explain the variations. For this purpose, different GIS programs, such as ArcView, ArcInfo, IDIRISI, and one geochemical modelling program, PHREEQC, has been used.

Energieffektivisering på Vista

Sweden has distinct seasons with cold winter and temperatures down to minus 25 ?C andpleasant summers with temperatures above 20 ?C. During spring and autumn there could becomechallenges with precipitation. The diverse climate in Sweden affects many homeowners. For thepeople living in leisure boats and permanent housing boats the seasonal changes are clearlyimpacting their economy and the indoor climate.

Tjäderns (Tetrao urogallus L.) vinterdiet i norra Sverige : är gran (Picea abies) viktig i vissa habitat?

In Scandinavia, capercaillie are often associated with pine trees (Pinus sylvestris) in winter, with pine needles as the main diet. Few dietary studies have been conducted in Sweden and winter diet is subject to little debate. The interesting thing is that this "pine specialist? is also found in spruce (Picea abies) forest habitats where pine is scarce or unavailable. In many studies outside Sweden (primarily Central Europe) spruce is regularly observed in the winter diet, but I have found no reports on the selection of the diet in spruce forest areas in Sweden.

Analys av system för rening av avloppsvatten i en anaerob membranbioreaktor

The most common way to treat wastewater in Sweden today is by a combination of an activated sludge process and a chemical treatment. These processes are not very energy efficient and may not be the most environmentally friendly. That is why it is interesting to evaluate new alternative methods to see if they can be less harmful to the environment and help to a lower resource consumption. New techniques are tested in a pilot installation at Hammarby Sjöstad, Sjöstadsverket. To be able to evaluate these techniques in a wide perspective system analyses are conducted where different impacts can be considered, advantages and disadvantages in the systems.Five system structures for water treatment have been constructed in Matlab/Simulink in this study.

Whole grain wheat : effects of peeling and pearling on chemical composition, taste and colour

The EU-project HEALTHGRAIN has suggested a new definition for whole grain which allows a small part of the grain to be removed during processing. By removing the outer part or the grain the hygienic quality will increase but it is not clear how the taste and colour is affected. So therefore in this study three different debranning methods, peeling, pearling and polishing, which remove the outer parts of the grains have been used on common and durum wheat. The dietary fibre and ash content, as well as germination was analysed in untreated, peeled, pearled and polished grains. The decrease in dietary fibre and ash was higher in grains that had been pearled compared to those that had been peeled or polished.

Kemisk stabilisering av gruvavfall från Ljusnarsbergsfältet med mesakalk och avloppsslam

Mine waste from Ljusnarsbergsfältet in Kopparberg, Sweden, is considered to constitute a great risk for human health and the surrounding environment. Some of the waste rock consists of sulphide minerals. When sulphide minerals come into contact with dissolved oxygen and precipitation, oxidation may occur resulting in acid mine drainage (AMD) and the release of heavy metals. The purpose of this study has been to characterise the waste material and try to chemically stabilize the waste rock with a mixture of sewage sludge and calcium carbonate. The drawback of using organic matter is the risk that dissolved organic matter can act as a complexing agent for heavy metals and in this way increase their mobility.

Optimering av sotningsfrekvens i biobränsleeldad CFB-panna : panna 5, Mälarenergi AB, Västerås

During the past 30 years the fuels for energy production in heating and power plants have changed. Fossil fuels have decreased in usage whereas bio fuels in Sweden have increased with 60% since the 1970's. Different fuels affects combustion and the release of various substances and particles into the flue gas. This is caused by the diverse components and chemical structures of fossil fuels and bio fuels. When the flue gas leave the combustion chamber and enters the path to the chimney particles in the gas are being transported out of the combustion chamber.

The legacy of the mill : a metal polluted forest soil in Gusum

Soils in a metal contaminated site on Stångberget in Gusum in southeastSweden were investigated and compared to relatively unaffected soils a fewkilometres away. Pollution came from historical release of untreated flue gasesfrom a brass mill. The objective was to find information on how high the metalconcentrations are, if metals from the polluted soil affect the surroundings andif the metal contamination affects the microbial community. The soil wasinvestigated using several different methods, such as field XRF measurements,chemical analysis of metal, carbon and nitrogen content, pH, acid neutralizingcapacity, texture, soil depth, field leach tests, sequential extraction and microbialfunctional profiles. The study showed that copper and zinc concentrationswere above Swedish Environmental Protection Agency guidelines for lesssensitive land use on the entire investigated area.

Mjölksyrabakterier som tillsatser vid ensilering av majs :

The project was initiated by Medipharm which produce microbial inoculants which used as additives to preserve forage. The main goal was to test three inoculants to produce maize silege. The following Medipharm produced inoculants were tested, Milab 393, Lactisil Wolecrop II, Lactisil 300 2. An untreated control was included in the study. The trial was done at Swedish university of Agriculture and Science in Alnarp, Sweden. Eurostar was the cultivar of the maize and was grown on 20, 5 hectares.

Den positiva hälsovågen : En kvantitativ studie om hälsofrämjande arbete

The construction of buildings and paved surfaces changes the natural water balance.Precipitation generates surface runoff and storm water instead of infiltrating into the soil.Storm water has come to be considered as a major source of pollution in lakes and streams inthe vicinity of urban areas. Reduction of pollutants in storm water is a key action in order toprotect sensitive recipients and maintain high water quality. Storm water is traditionallytransported by storm sewers to the nearest recipient. In recent years the approach to stormwater management has changed; storm water should primarily be disposed of on site, throughlocal disposal of storm water, LOD. LOD is created by a combination of the function ofseveral smaller local facilities and the general sewer system.

Retention av tungmetaller i en anlagd våtmark : studier av Vattenparken i Enköpings kommun

The aim of this study was to examine the amounts of heavy metals in the sediment of a wetland constructed for stormwater treatment. The wetland is called Vattenparken and is located in the city of Enköping. The heavy metals which were analysed were Pb, Cd, Ni, Zn, Cu, Cr and Hg. The total metal concentrations were determined using HNO3 chemical extraction. From 8 sampling sites 5 sediment cores were taken.

Mobiltelefon utformad med EcoDesign

The environmental demands are increasing when it comes to product development. EcoDesign isabout minimizing the environmental impact of a product, considering the entire life cycle of it,without compromising other qualities like function or cost. In this master of science thesis amobile phone has been analysed with Ten Golden Rules in EcoDesign regarding production, useand End of Life. Also a functional and an environmental profile were made. The goal was tomake a new concept phone, based on the previous analysis, which communicates userfriendlinessand sustainable development.

Återvinning av textil

Syftet med rapporten var att studera möjliga återvinningstekniker för Ragn-Sells. För detta användes litteratursökning och intervjuer. Återvinningstekniker som studerats är mekanisk bearbetning, mekanisk återvinning, kemisk återvinning och viskostillverkning. Flera underklasser till dessa metoder studerades också, liksom flera sätt att tillverka återvunna produkter. Rapporten nämner ett urval av återvinningstekniker och försöker inte nämna alla tillgängliga återvinningstekniker.Återvinningsteknikerna har sorterats enligt prioriteringen i EU:s återvinningsdirektiv (2008/98/EG).

Handelsutvecklingen efter Lettlands självständighet : En studie om ekonomisk transition under perioden åren 1993 fram till 2004

The main purpose of this essay is to investigate if Latvia´s pattern of trade has become more similar to the mature market economies, after Latvia´s independence 1991.Today, the intra-industry trade (IIT) dominates the trade of mature market economies. One of the pioneers of intra-industrial trade is Paul Krugman, who was the first to emphasize the importance "of scale and consumers' desire for variety" in explaining the basis for modern commerce. Customers get more variety and usually cheaper goods when the market gets bigger. I mainly use the modern trade theories to explain the trade pattern in Latvia. To measure how Latvia has developed its intra-industry trade, and thereby is approaching the mature market economies´ trade pattern, I use the Grubel-Lloyd index (GL-index).

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