The research group Soil and Water Management at the department of Soil and Environment at theSwedish University of Agricultural Sciences in Uppsala are studying greenhouse gas emissions fromcultivated peat soils. To measure carbon dioxide emissions from peat soils in the field the researchgroup are now using two portable carbon dioxide meters (Vaisala GMP343). For practical reasons,they plan to acquire a new type of automated field meter. The aim of this study is to evaluate thepresent meters to see how environmental conditions and instrument settings affect the results,which is meant to facilitate the introduction of the new field meter when the meters needs to becompared. As a part of the study the relationship between groundwater level and carbon dioxideemissions from peat soils will be investigated.The evaluation of the two carbon dioxide meters was made by connecting them to one single airtightsystem, with the aim of creating identical measurement environments.

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).

Landfill leachate contains a variety of contaminants and is created when rainwater percolates the landfill. For landfill management the leachate is the main issue that can cause problems to the environment. At the landfill of Fläskebo, Renova AB treats the leachate in a local treatment plant. The treatment consists of a chemical treatment step with chemical precipitation, flocculation, sedimentation and filtration, and a final step with a Carbon and peat filter. Renova has to ensure that the condition of the leachate reaches the regulation set for the landfill before it is released to the recipient.

Filtermaterial av 75 % torv och 25 % kolaska har använts under 2 respektive 4 år för rening av avloppsvatten från två biltvättar. Jämförelse med Kristianstads kommuns riktvärden för avloppsvatten från fordonstvättar visar att filtren fungerat. För avfallsklassning krävs kunskap om innehåll av miljöfarliga ämnen i produkter som använts i tvätthallarna. I brist på kunskap om innehåll av ej analyserade miljöfarliga ämnen i filtren anses förbränning vara ett bra omhändertagande ur miljösynpunkt, då energi och aska återvinns..

The purpose of this study has been to examine whether the bottom fauna of the stream Stensjöån, has been negatively influenced since the harvesting of peat began on the nearby peat moss Skäftesmyr or not. Comparison has been made with the results of index calculations from earlier examinations in the stream, two calculated indexes has been made, Danish fauna index and ASPT-index. The sampling was made with the kick sampling method, SS-EN 27 828. Three locations were chosen for the examination, one upstream from the peat moss, one just downstream from where the brook from the peat moss joins Stensjöån and a third location near the outlet of the stream to the lake Stensjön. The samples were sorted and the found animals identified to the taxonomic level required for the calculation of the two indexes.

Carbon offsetting means to offset those greenhouse gases that are caused by our actions. The purpose of this paper is to examine how companies are working with carbon offsetting. The focus of the research is how travel agencies and companies that provides carbon offsetting. The writers also highlight the problems carbon offsetting is facing. The study was performed with qualitative methods through interviews with three companies working with carbon offsetting.

How to create a more effective filter for the dishwashers of tomorrow..

In order to facilitate testing of anesthesia machines a patient simulator has been required by Maquet Critical Care AB. A patient simulator has been developed to reduce expensive and time consuming animal experiments and temporary lab arrangements. The patient simulator has been developed and designed to simulate human lungs with regards to anesthetic uptake, production of carbon dioxide and heating and moisturizing exhaled air.The system comprises a container and a test lung to simulate the volume and the dynamic of the human lung. The simulation of uptake of anesthetics has been implemented by pumping a fraction of the gas from the container through a bypass circuit with an active charcoal filter that adsorbs volatile anesthetics. The flow through the bypass circuit is generated by a pump and is controlled by a linear valve.The resulting performance of the patient simulator has fulfilled the requirements.

The background of this work is the media discussion about the effect of cultivation on peatsoils on greenhouse gas emissions. It has been argued that row sown and intensivelycultivated crops such as carrots are more likely to emit carbon dioxide than for example grassleys. The association KRAV (an association promoting organic farming) shall, from this yearadapt their environmental policy to be more climate smart and have asked the question if thecultivation of some crops is more climate smart than others? Carbon dioxide emissions fromsoil are due to degradation of organic material and the rate is controlled by microbial activity.The microbial activity is determined by a variety of factors such as temperature, soil organicmatter quality and water content. I have measured the carbon dioxide emission from fourdifferent crops at two different farms.

Peat litter has been used in animal houses for a long time. Because of its good ability to absorb liquid and nutrients from the manure it can create a dry surface for animals and a valuable manure product. Through changes in agricultural practises the use of peat litter has diminished and is to a great extent replaced by straw, sawdust and cutter shavings although Sweden is rich in peat-findings. The aim of this work was to summarize the presented knowledge about the used of peat litter, techniques, advantages and disadvantages and to compare with other commonly used litter materials. Articles on peat litter have been searched for in magazines, databases and books at SLU library. Visits to peat industries, interviews with peat producers and with peat researchers contributed to the material. Peat is not a uniformly material.

Peat litter is a soft material with high absorbency. About hundred years ago many farmers in Sweden used peat litter to their dairy cows. After the World War II the use of peat litter decreased and the farmers used more straw. Nowadays (year 2007), when it is harder to find straw and sawdust to buy, peat litter is advancing again. The purpose with this study is to investigate peat as a litter to dairy cows.

A patient simulator for testing anaesthesia machines has been developed at Maquet Critical Care AB, to reduce costly and time-consuming experiments on animals. The device simulates human lungs regarding lung dynamics and volume, uptake of anaesthetic agents and the production of carbon dioxide, heat and moisture. Further demands on the simulator are durability and size; the device shall be compact enough to be moveable.The resulting simulator fulfils the requirements and enables better repeatability and ability to test extreme cases than experiments on animals do.Uptake of the anaesthetic agent is achieved in a active carbon filter and controlled by regulating the flow. The flow is created by a regenerative blower and controlled using a proportional valve. The uptake can be set by the user or by a simple uptake model modified to recursively handle changes in the concentration of anaesthetic agent.Carbon dioxide is fed into the system from a tank by a mass flow regulator.

This paper describes the work done trying to diminish the noise present in the signal from an IR-detector. The project was aiming towards two different kinds of applications; heat protection and presence detection. The hypothesis was that the signal-noise ratio would decrease if a filter and a proper installation were used for the detector. Some experiments were executed to determine what kind of filter were the most suitable for each application and how these could be installed. After executing the experiments and evaluate the results we recommend to use a specific filter for each application.

IIR-filter är överlägsna traditionellt skapade FIR-filter på många punkter. De klarar sig med en klart lägre ordning för att realisera ett filter med samma egenskaper. En nackdel är däremot att filtret är klart känsligare för koefficient kvantisering och förlorar sina egenskaper när koefficienterna ändras, detta inträffar även om förändringen är liten. Genom den speciella struktur som vågdigitala filter använder sig av kommer man runt detta problem. Det betyder bl.a.

Normally the operational amplifier is used as a component in active filter design. The goal for future components in filter design is large bandwith and the use of low supply voltages. The use of current-mode instead of voltage-mode circuits gets a step closer to the required performance. A component that use current as the signal conveying part is the current conveyor. In this report a comparative study between two current conveyor structures of second generation (CCII) is performed.