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353 Uppsatser om Chemical precipitation - Sida 16 av 24

Fukthalt i GROT - påverkande faktorer :

This study was carried out at the request of the bio energy company Naturbränsle. The company handles annually 750 000 m3 of chips from logging residues from a large area, from Östergötland in the south to Härjedalen in the north. In that area, about 50 bio fuel plants are customers. When Naturbränsle deliver chips from logging residues to their customers, the moisture content varies from 30 % to 60 %. The aim of the study was to sort out the affecting factors on the moisture content in the chips during handling and storage processes.

Cykelparkering i stadsmiljö : en redogörelse för cykelparkeringens komponenter

In recent years many cities have seen an increase in bicycle traffic. This is a development that benefits both the environment and the individual cyclist. When the need for bicycle parking is not met several problems arise such as an increase in bicycle thefts, jammed sidewalks and a decreased interest in using bicycles. My aim with this paper has been to answer the question of how to create parking facilities in an urban environment based on cyclists' needs. Through a literature survey, following the method "Trattmodellen" (the funnel model) the question has been answered and divided under the headings cyclist, bike, bicycle racks, bicycle garage and bicycle operators and hosts.

Reducering av DOC beroende av karaktär med fyra dricksvattenberedningstekniker : Jämförelse mellan fällning (FeCl3 och Al2(SO4)3), membranfiltrering och jonbyte med MIEX®

Halten löst organiskt material (DOC) har under de senaste 20 åren ökat i våra sjöar. Det har också skett förändringar i karaktären. DOC ställer till problem för vattenverk som använder ytvatten som dricksvattenkälla genom att det kan ge lukt, smak och färg till vattnet. Det ger också ett ökat behov av fällningskemikalier, större slambildning och större bildning av potentiellt skadliga desinfektionsprodukter. I och med förändringarna i halt och karaktär av DOC behöver nuvarande reningstekniker förbättras och nya tekniker utvecklas.I den här studien undersöktes två konventionella reningstekniker; fällning med järnklorid och fällning med aluminiumsulfat, samt två modernare tekniker; jonbyte med MIEX® och membranteknik.

Tätning eller ventilering mot fukt på kalla vindsutrymmen

This study was done regarding whether sealing or ventilation is the best solution to prevent moisture on cold attics. The authors of this report addressed the problem with moisture in attics when they started their cooperation with Peab.The methods included interviews with people, database research, and calculations of a project in Akersberga north of Stockholm. The conclusion is based on interviews and other information as they are analyzed in relation to the house of reference. The focus of this report is on problems with moisture in the attics known as cold attics.The background of the problem with moisture is that today?s slabs are usually insulated to save energy and that the attics nearly gives the climate as the outdoor climate.

Integrerad arbetsprocess mellan projektör och konstruktör, För effektiv och kvalitetssäker projektering med Tekla Structures och SAP2000

The purpose of this work is to design and construct a device able to measure the mechanical attrition of oxygen carrier particles. Those particles are used in chemical looping combustion and in the present situation there is a lack of knowledge in how the attrition process work and in which extension. To find already tested solutions trying to answering this problem a literature study wascarried out and the best solution found was the so called Grace-Davison Jet-Cup method. This method is supposed to emulate the attrition caused by a cyclone separator and its advantages are that it is possible to use small test amounts, 5-10 g, and a thirty minutes long test will be enough to acquire useable results. An device was designed based on the Jet-Cup method with some slight modifications.

Plant defensive mechanisms against insect pests

This study has focused on testing the following two hypotheses:? Pest resistant plants have higher levels and/or several different kinds of secondary metabolites. ? Induced defensive systems in resistant plants are activated more rapidly than those of susceptible plants. As a background for the test of the hypotheses a short literature study was performed concerning plant defensive mechanisms in Arabidopsis thaliana.

Silver och vismut i plaster och färger : Källor till förhöjda halter i slam?

Chemical substances are spread diffusely and uncontrollably as a result of the increased consumption of goods. REVAQ is a certification system that works to reduce the flow of hazardous substances to Swedish treatment plants and to create a sustainable nutrient recycling. According to REVAQ, the yearly accumulating rate of metals should not exceed 0.2% in soil per year. Silver and bismuth are two metals that do not fulfill this requirement. The silver concentration in sludge decreased during the last decade, however the last few years, it has leveled off.

Morfologisk och kemisk beskrivning av en svensk rabarbersamling (Rheum raponticum L.) :

SAMMANFATTNING Mitt examensarbete utgör ett led i Nordiska Genbankens (NGB) uppgift att skapa en nordisk s.k. ?core collection? av rabarber, Rheum rhabarbarum L. Samlingar finns även i våra nordiska grannländer Norge, Finland, Danmark och Island. I Sverige har ett insamlingsarbete av rabarber pågått under åren 2002 och 2003 för att komplettera en äldre samling.

Uppfångning och kvarhållning av 134Cs och 85Sr i olika växtutvecklingsstadier

Emissions of radionuclides to the atmosphere can lead to wet deposition on plants in the event of rainfall. An increased level of radioactivity in the plants may occur due to interception and retention of the radionuclides. If the content of the plants is above the threshold limit value, entire yields may have to be destroyed. In order to prevent contamination or decrease the content countermeasures can be taken. The impact of the biomass, leaf area index (LAI) and growth stage of the plant on the interception and retention is important to know in order to decide which countermeasures to use. Weather may also be an important factor. In this work the interception and retention of 134Cs and 85Sr by spring wheat, ley and spring oil-seed rape was studied.

Några vanliga ogräs : en litteraturstudie av arternas biologi samt förebyggande och direkta kontrollåtgärder

The Swedish Board of Agriculture initiated this undergraduate thesis. There is a database on their homepage that includes chemical treatments for different weed species. There is also space for preventive and mechanical control methods. This is an undergraduate thesis that reviews these control methods for the most important weeds in Sweden. The species reviewed are: Creeping perennials: Common Couch Elytrigia repens (L.) Desv. ex Nevski Creeping Thistle Cirsium arvense (L.) Scop. Perennial Sow-thistle Sonchus arvensis L. Field Horsetail Equisetum arvense L. Colt's-foot Tussilago farfara L. Stationary perennials: Dock Rumex L. Mugwort Artemisia vulgaris L. Dandelion Taraxacum F.

Tonalitet i tjugoförsta århundradet : Populärmusik och spel med tonala konventioner

 AbstractJohan Landgren: Tonalitet i tjugoförsta århundradet ? Populärmusik och spel med tonala konventioner. Uppsala universitet: Institutionen för musikvetenskap, C-uppsats 2007.I uppsatsen studeras spelet med tonalitet och tonala konventioner i den nutida populärmusiken. Fyra låtar (av Avril Lavigne, Fall out boy, My chemical romance och Nickelback) analyseras med avseende på melodi och harmonik, för att visa hur musiken förhåller sig till traditionella tonala system. Den teoretiska utgångspunkten är en diskussion av Carl Dahlhaus om indelningen av musik i harmonisk respektive melodisk (modal) tonalitet, och i underkategorierna tonarter respektive modi.

Uppfångning och kvarhållning av 134Cs och 85Sr i olika växtutvecklingsstadier

Emissions of radionuclides to the atmosphere can lead to wet deposition on plants in theevent of rainfall. An increased level of radioactivity in the plants may occur due tointerception and retention of the radionuclides. If the content of the plants is above thethreshold limit value, entire yields may have to be destroyed. In order to preventcontamination or decrease the content countermeasures can be taken. The impact of thebiomass, leaf area index (LAI) and growth stage of the plant on the interception andretention is important to know in order to decide which countermeasures to use.Weather may also be an important factor.In this work the interception and retention of 134Cs and 85Sr by spring wheat, ley andspring oil-seed rape was studied.

Kraven på ägare till minireningsverk skiljer sig åt mellan olika kommuner

Discharge of inadequately treated waste water containing nutrients such as phosphorus and nitrogen as well as organic matter and bacteria is associated with a risk of eutrophication and contamination. The Swedish government has decided upon several Environmental Quality Objectives aiming to reduce the emissions of nutrients to water bodies.In Sweden, there are between 675 000 to 1 000 000 on-site sewage systems. Recent studies have shown that the function of small sewage treatment plants is in many cases insufficient. To prevent this regular service and supervision by a professional is needed. The focus of this study are small sewage treatment plants which use a technique where mechanical, chemical and/or biological reduction of pollutants is being used in the same facility to reduce nutrients in household wastewater.The aim of the study is to investigate how different municipalities ensure that small sewage treatment plants fulfill the requirements and reduce pollutants as efficient as the manufacturers claim.

Metodik för bestämning av åkerdikens status : fallstudie av ett dike i Munktorps socken

Agricultural drainage ditches are links between fields, lakes and oceans, having the potential to transport e.g. sediment and nutrients. When in a good condition, drainage ditches can act as sinks for e.g. phosphorus and sediments and prevent eutrophication downstream. The aim of this study was to determine the condition of one agricultural drainage ditch and to come up with suggestions for appropriate measures. The aim was also to determine which of the ditch?s properties that were possible to evaluate visually, which processes they represented as well as which properties required complementary physical analysis. This in order to contribute to the work of developing a method for determining the status/condition of agricultural drainage ditches.

Lättlösliga kolhydrater i vallfoder och i hästens grovtarm :

The purpose of this study was to investigate how the content of glucose, fructose, sucrose and fructan (WSC) varied in silage, haylage and hay harvested from the same field and at the same time of harvest. The study also investigated if differences in the WSC-fraction in the forages caused differences in composition of WSC in the colon of horses fed the forages. Hay, haylage and silage were harvested in the first week of June 2005 and stored for about nine months before feeding. Horses that were fistulated in right ventral colon and caecum were used, but only the colon fistula was used for sampling. The fresh crop and the conserved hay, haylage and silage were analyzed for chemical composition and WSC-fraction.

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