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50 Uppsatser om Nitrous oxide - Sida 3 av 4

Syntes och egenskapskarakterisering av volframoxid framställd med magnetronsputtring

The system tungsten-oxygen has potential of being suitable for decorative coatings since ceramic coatings are often hard and wear resistant, and since modulations in oxygen content or incorporation of small ions could give bright colours. The aim of this report was to investigate the relationship between process parameters and  the properties of the films, with the wear resistance being of special interest.Samples with tungsten to oxygen ratios in the range of 100:0 to 25:75 at% were made using reactive sputter deposition, either with constant gas flow, or gas flow controlled by optical emission of the plasma. The hysteresis of the system, which means that a certain gas flow will cause different pressure and/or target voltage depending on in what way the flow is reached, makes it interesting to control the process where the system makes the steep change from metallic tungsten to ceramic tungsten oxide. This is difficult and thus requires precise control equipment.The samples were analysed using X-ray diffraction, X-ray photoelectron spectroscopy and an empirical wear test suitable for small components like cell phone cover for example, in order to characterize the structure, composition and wear resistance of the coatings. The results could be divided into three groups: (I) tungsten-like, with very low oxygen content; (II) mixed phase and (III) tungsten oxide like, with oxygen content close to 75 at%.

En jämförelse av RDF och avfall som förbränningsbränsle

In the EU the amount of waste increased by 14 percent during the years 2000 to 2010. EU?s target to reduce waste generation runs parallel with the aim of increasing the efficiency and profitability aligned with energy recovery. In Sweden the energy recovery through incineration is increasing steadily, and 46 percent of the municipal solid waste (MSW) is treated by combustion. This report aims to examine the profitability of processing MSW into Refuse Derived Fuel (RDF) from an economic-, energy- and environmental perspective.

Historiska emissioner av bly och arsenik till luft från Åfors Glasbruk och deras konsekvenser för miljön.

Åfors glasswork was a company which started in 1876 and closed in 2012 due to the bad economical situation in the company. After its closure, the glasswork left behind contaminated soil with different concentrations of heavy metals such as, arsenic from arsenic trioxide, a chemical used to remove bubbles during the melting of glass, and lead oxide, a chemical used in the production of crystal glass. Crystal glass?s production occurred under 1921-1971, but emissions of lead into the air from Åfors glasswork continued until 2011, because of the artist Bertil Valliens? artglas was made in Åfors glasswork from 1970?s and onwards.The aim of this study was to estimate how much lead (Pb) and arsenic (As) that were released by Åfors Glasswork into the atmosphere during the operational period of the glasswork in comparison with how much of lead and arsenic were purchased for the company. Added to the assistance of the data from National Archives the variations in the activities of Åfors glasswork could be shown.

Optisk karakterisering av tunna SiO2/NiO-filmer syntetiserade med en sol-gelmetod

In an attempt to develop a more cost-efficient material for solar   energy applications, nano-particles of nickel oxide composite in a silikatmatris manufactured with solar gelmethod and studied structurally by electron microscopy. Furthermore, the thin film optical properties characterized by Variable. Angel Spectroscopic Ellipsometry. Sol gelfilms suitability as a selective absorber surface is also analyzed by optical modeling..

Kalciums och magnesiums inverkan på arsenikavdrivningen i virvelbäddsugnen : The influence of calcium and magnesium on the expellation of arsenic in the fluidized bed furnace

In the fluidized bed furnace at Rönnskärsverken, Skelleftehamn, sulphur-containing ore concentrates are roasted in order to remove about 50% of the sulphur in the incoming ore concentrate. This occurs in order to reach the goal of a matte containing 55% of copper in the following smelting process. At the same time as the ore concentrate is partially roasted pollutions as arsenic, antimony and bismuth are expelled. Earlier made thermodynamic calculations of equilibrium suggested that calcium and magnesium form stable compounds with arsenic and thereby inhibit expellation of arsenic in the fluidized bed furnace, an element that is undesired. The purpose of this thesis work was to gain knowledge of the mechanisms behind the formation of these stable arsenic compounds.

Modellering och reglering av ureainsprutning på kraftvärmeverket FTG

The aim of this thesis is to improve the control of urea injection at the combined power and heating plant Framtidens Gärstad (FTG). Tekniska Verken i Linköping AB is the owner of the plant.The FTG plant consists of a boiler where garbage combustion is done. From the combustion nitrogen oxides are emitted. These nitrogen oxides are hazardous to the environment. To reduce the nitrogen oxides, injection of urea into the boiler is used.

Restriktioner av växthusgasemissioner : hur påverkas lantbruksföretagens ekonomi och produktionsinriktning?

The agricultural sector accounts for about 13 percent of the total load of greenhouse gas emissions from Sweden (Swedish Environmental Protection Agency, 2007). The Swedish objective to reduce the greenhouse gas emissions with 40 percentage units to the year of 2020, based upon the year of 1990, might imply stricter regulations for Swedish farmers. A regulation or other forms of economic incentives is probably necessary to reduce the emissions originating from the agricultural sector. This study aims to investigate the economic and managerial impact on two agricultural firms with differing production system given that a constraint on green house gas emissions is introduced. Gases included in this study are carbon dioxide, methane and Nitrous oxide.

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.

Magnesium chloride in dry cow silage to prevent hypocalcaemia

Milk fever, or parturient paresis, is the second most common disease in Swedish dairy cows. The disorder is associated with the onset of lactation when some cows are unable to meet the metabolic demands of calcium to support milk production and therefore develop a state of hypocalcaemia. Clinical hypocalcaemia (milk fever) may lead to coma and death in severe cases but subclinical hypocalcaemia has also been shown to have negative effects on e.g. feed intake and production and to increase the susceptibility of the cow to develop secondary diseases. The nutritional strategy applied precalving is of great importance in preventing milk fever and e.g.

Naturlig förekomst av arsenik och avskiljning av arsenik från grundvatten : test av olika filtertekniker avsedda för enskilda brunnar

During the last few years the presence of high arsenic (As) concentrations in ground water has been of major concern both internationally and in Sweden. Much evidence has been reported about toxic effects caused by arsenic. The carcinogenic effects and the possibility to measure the toxic impacts at low concentrations made the World Health Organisation (WHO) to reduce the guideline value from 50 to 10 ?g l-1 in 1993. In Sweden the corresponding reduction was implemented in 2003. Several surveys in Sweden have shown that high arsenic concentrations may occur in ground water.

Temperaturens och den fotosyntetiskt aktiva strålningens effekt på avgång och inlagring av kol på en dikad torvjord

The decomposition of organic carbon in drained peat soils is a major source of carbon di-oxide in Sweden. A big part of these drained peat soils are used in agriculture and it is a big challenge to slow down their decomposition. It has earlier been thought that less tilling and higher water table levels would decrease the activity of soil microbes and thereby the decomposition, but recent experiments has showed that this has little or no effect. In this bachelor thesis a field experiment was made on drained peat soil with ley, outside Björklinge, Uppsala municipality, Sweden. The experiment was carried out in May 2011. The objective was to develop a method to examine how the net exchange of carbon diox-ide from plant covered peat soil is affected by temperature and photosynthetically active radiation (PAR).

Jordbruksdränering, kostnader och genomförande :

Underdrainage is a costly investment but often a necessity to maintain rationalized plant cultivation, one can also see underdrainage as insurance to successful plant cultivation. Late ripening crops, low yield and difficult tillage cultivation are examples on an insufficient drainage. (Kvarnemo 1983) A drained field rise in land price and the scheme of the tiled drains is seen as a value item. The interest for underdrainage among the farmers follows with shifting economic situations within agriculture and has for long time been low. A big part of the Swedish tiled drainage systems is since 1930 and ahead. Many of these tiled drainage systems need to be replaced or complemented. The life length of one tiled drainage system varies with maintenance but can still remain in good function after 75 years with correct management.

Syrgasdelignifiering av magnesiumbaserad sulfitmassa med magnesiumbaserad alkali

Syftet med arbetet var att undersöka hur olika reaktionsbetingelser skulle påverka syrgasdelignifieringen av en sur sulfitmassa. De betingelser som undersöktes var utbyte, slut-pH, viskositet och kappatal. Massan som användes kom från Nordic Paper Seffle och alkalit som användes var magnesiumoxid. Syrgasdelignifiering av massan gjordes  i autoklaver i ett PEG bad där tid, temperatur och alkalisatser varierades.Resultaten visar att alla utbyten låg mellan 90-97% och att även de mest aggressiva betingelserna bara gav en viskositets reduktion på 260 enheter, motsvarande 19% av den totala viskositeten.Slut-pH för syrgasavluten hamnade mellan 6,5-9,4 beroende på alkalimängd och temperatur under delignifieringen. Slut-pH minskade när mängden alkali hölls konstant men temperaturen varierades mellan 110-140°C.Kappatalet för massan kunde effektivt reduceras från ett startvärde på 23,4 till ett slutvärde på under 5 med en temperatur på 140°C, alkalisats på 10 kg/ODT och en tid på två timmar utan större förluster av vare sig viskositet eller utbyte.En ovanligt resultat som upptäcktes under arbetet var att delignifieringen tappade i effektivitet med ökad alkalimängd och detta samband gällde vid alla betingelser.En teori om detta kan vara att jonstyrkan i lösningen gör att fibrerna i massan drar ihop sig och att syrgasen får svårare att reagera med ligninet..

P?verkar intag av ?gg niv?er av trimetylamin-N-oxid i blodet? En systematisk ?versikt

Syfte: Syftet med denna systematiska litteratur?versikt var att unders?ka det vetenskapliga underlaget kring om regelbundet intag av ?gg p?verkar niv?er av trimetylamin-N-oxid (TMAO) i plasma hos vuxna. Metod: En litteraturs?kning genomf?rdes i databaserna PubMed, Scopus och Cochrane Library 25 januari 2023. Inklusionskriterierna var vuxna ?18 ?r, intervention best?ende av ?gg eller ?ggula, kontroll best?ende av ?ggsubstitut/?ggvita/habituell kost/annat livsmedel som inte inneh?ller ?ggula, utfallet TMAO i plasma och studiedesign RCT. Artiklarna skulle vara skrivna p? engelska eller svenska.

Vad är ?rätt? gjutkvalitet? Hur uppnås det?

Ever since ABB has begun diecasting their rotors instead of permanent mold casting it,variation in the quality of the cast has arisen. Diecasting is performed in three differentmachines, M1, M2, M3 with 400, 660 respectively 800 tons of die locking pressures.The aim of this thesis is to answer the following questions:What is the ?right? cast quality? How is the right quality achieved?For sizes 160-180 solutions will be proposed that consider eccentricity between thelaminate and the short circuit ring as well as elimination of the thin Al film that appearson the outer periphery of the rotors.Through considering the statistic material the most often diverging rotor type has beenidentified and one of the actual rotors has been sent to a laboratory to be analyzed inorder to establish the current defects. The result of the analysis shows that there areplenty of gas- and oxide-porosity.It has been proved that every time the dies temperature decreased below 120°C thecontent of gas porosity increased. It is due to rapid solidification of metal that flowsthrough the ?cold? laminate.It has confirmed that enhanced porosity in squirrel cage causes high impedance in therotors.

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