This master thesis reviews advances in detection and diagnosis of static friction (stiction) in control valves. Control valves suffering from stiction results in oscillating control loops which in turn decreases both the process stability and reliability. Perstorp AB sees a necessity to automatically detect stiction in valves before the effects of the malfunctioning valves have become too severe. This thesis presents an introduction to maintenance, control loops and how stiction in valves can affect performance of control loops.A selection of methods presented in the literature are introduced and examined using normal operating data from the site in Perstorp. Common for all selected methods is their intuitive ideas and that they are based on normal operating data and minimum amount of process knowledge.

Outdoor recreation habits in metropolis and rural areasThis study aims to examine the perception of nature and outdoor recreation habits from an urban-rural prospective. The urbanization process continues in Sweden and the populations of the cities are growing continuously. Trends to build more compact and ?climate smart? reigns and with this a risk that green areas and areas where outdoor recreation can be practiced are situated further and further away from the urban population. Analyzing the responses from a survey made by the research program Friluftsliv i förändring 2007 we have examined if and which differences exists between urban and rural areas regarding their perception of nature, outdoor recreation habits and factors influencing the practice of outdoor recreation.

Göteborg Energi has a surplus of district heating during spring, summer and fall. The heat surplus is due to a constant production of waste heat from oil refineries and heat from waste incineration over the year. It would be desirable to increase the demand for heat and the uptime for the newly built combined heat and power generation plant, Rya Kraftvärmeverk. One alternative could be to integrate Rya Kraftvärmeverk with a pellet production facility. By producing heat, electricity and pellet in a joint process the energy use can be decreased.

This paper appeals to professionals working with green questions. It intends to create a discussion about which plant species that can be established in a fieldlayer of a naturelike planting on fertile agricultural land. To initiate the essay, a studie of which values that can be connected with an establishment of a fieldlayer was performed . A part of Tor Nitzelius Park in Alnarp, a so called naturlike planting on fertile agricultural land, was used as a model for the choice of species. With the aid of soil values, photos and a list of current species, interviews with four ecologists were performed.

Abstract:Perennials in public areas have during the latest decades been more and more popular. This group of plants has become a more accepted komponent when creating pleasant public places, and people begin to see the functional aspects. Perennials do also give a colour- and senceexperience in a more detailed way than can be achieved with only trees and shrubs. One of the ojects of this essay is to give more examples of motives for using perennials in urban areas.Having in mind the increasing use of perennials, you can expect a growing need for better understading of how to create successfull perennial plantings. In spite of the increasing interest it is hard to find any written information in this subject.

Wastewater handling of private sewage systems has become an all increasing matter. In Stockholm region the 90 000 private sewage systems contribute with larger phosphorus flows to the Baltic Sea than the two biggest sewage plants in the area, Henriksdal and Käppala, contribute together, even though these two plants purify wastewater from more than one million inhabitants. When summer house areas turn into areas for permanent living ? transition areas ? the load on the existing systems increases, systems that already often are unsatisfying. In those areas it is not clear what the best system choice is; On-site systems for single households; Local collective systems or Connection to central systems.

Phosphorus is essential to all plants and is taken up from the soil as the ion H2PO4 - (and to some extent HPO42-). Plant availability depends on, among other factors, the soil pH. In order to provide for plant available phosphorus, it is applied as mineral fertilizers and farmyard manure. However, that causes phosphorus leaching from arable land to surrounding surface waters and lakes and contributes to the eutrofication. There are three types of soils in Sweden that are at higher risk of contributing to phosphorus leakage.

This master thesis was conducted in order to investigate the effects of the browsing species Yeheb on animal tissues in Swedish landrace goats and to make a literature review in order to increase the knowledge of the importance of this plant for livestock production in Somalia. The evergreen Yeheb bush is a very important feeding source for grazing and browsing animals in Somalia during the dry period. Yeheb contains cordeauxiaquinone that stains the bones of the animals red/pink, which has been an increasing problem when exporting meat to foreign countries. In an experiment, two goats were fed dry and fresh leaves from the Yeheb bush for one and two months, respectively. The goats did not feed the intended amount of dry leaves, since the supply and palatability was not as high as estimated.

The main project Dry preservation of source-separated organic household wastes involves a new technique for treatment of biowaste through drying. Investigations are going on to determine how the dried biowaste best can be used to close the natural circular flow of nutrients. The objective of this degree project is to determine if the dried biowaste can be used as a soil conditioner. By restoring the nutrients in the material to the ground, the natural circular flow is closed. A declaration of contents, including the nutrient levels, C/N ratio, pH and the electrical conductivity of the dried biowaste, was constructed and a germination test was done to make sure that the material did not inhibit sprouting.

Vattenfall Heat Uppsala runs the waste incineration plant in Uppsala, which produces district heating, process steam, district cooling and electricity. Vattenfall Heat Uppsala has decided to introduce an energy management system with the aim to increase the energy efficiency of the plant. The basis in such a system is to make an energy mapping.In this thesis an energy mapping has been performed at the waste incineration plant with the aim to identify and determine the size of energy flows. The investigated energy flows are used fuel, produced and used steam, produced district heating and cooling. Also the use of electricity to run the processes has been investigated.

The purpose of this thesis is to investigate and clarify the facts surrounding one of Vattenfall's district heating plants; The "solar field" and associated rock cavern in Lyckebo, Storvreta. The plant was built in the '80s by the formerly municipal utility,Uppsalakraftvärme AB, as an experimental building. A ground water filled cavern would serve as seasonal storage of solar heat from an adjacent solar field. Since both the energy company and the facility itself has undergone major changes over the past 30 years, there was a great need to gather facts in order to provide a picture of its current condition and potential for continued use. The thesis investigates the plant's history and problems with the rock cavern losses, and how the operation developed. It also presents the calculations regarding the possibilities of again supplementing the facility with solar energy - which is not the case today - as well as the economic conditions for it. Regarding a re-launch of solar energy, primarily a concentrating solar collector has been studied, as it has the advantages of an integrated control system.

Two elementary schools are now being built in Gråbo (in the municipality of Lerum),Röselidsskolan and Ljungviksskolan, which are both designed with solar thermalcollectors for the schools domestic water heating. During the summer while thelargest amount of solar heat can be generated, the activity hence the domestic wateruse in the schools are heavily reduced. Both schools are connected to the local districtheating system which makes it possible to use the solar collectors to deliver heat tothe district heating.The purpose of this thesis is to evaluate the two systems mentioned above and todetermine which system is more suitable to apply on a school. The building whichconditions were used for this evaluation is Röselidsskolan.A solar heating plant of each system type was dimensioned from the expected andknown conditions of the building. The purpose with the dimensioning was to makethe solar plants replace the ordinary energy source as much as possible.

Two elementary schools are now being built in Gråbo (in the municipality of Lerum),Röselidsskolan and Ljungviksskolan, which are both designed with solar thermalcollectors for the schools domestic water heating. During the summer while thelargest amount of solar heat can be generated, the activity hence the domestic wateruse in the schools are heavily reduced. Both schools are connected to the local districtheating system which makes it possible to use the solar collectors to deliver heat tothe district heating.The purpose of this thesis is to evaluate the two systems mentioned above and todetermine which system is more suitable to apply on a school. The building whichconditions were used for this evaluation is Röselidsskolan.A solar heating plant of each system type was dimensioned from the expected andknown conditions of the building. The purpose with the dimensioning was to makethe solar plants replace the ordinary energy source as much as possible.

The society of today is overflowed with information and commercials. There is a thick media noise that the marketers finds hard to penetrate. Bearing this in mind, we can see that Event Marketing, witch is marketing through events, has grown to be a popular form of communication as it has an ability to work its way through the existing media noise. Through events a company can strengthen its brand and image as well as form a lasting relationship with its consumers. What other functions does Event Marketing possess? In what context is Event Marketing an appropriate marketing strategy to use? These are two questions that we aim to answer through this essay.To be able to answer these questions we interviewed the marketing manager of two different companies, L´oréal and TeliaSonera.

Two elementary schools are now being built in Gråbo (in the municipality of Lerum),Röselidsskolan and Ljungviksskolan, which are both designed with solar thermalcollectors for the schools domestic water heating. During the summer while thelargest amount of solar heat can be generated, the activity hence the domestic wateruse in the schools are heavily reduced. Both schools are connected to the local districtheating system which makes it possible to use the solar collectors to deliver heat tothe district heating.The purpose of this thesis is to evaluate the two systems mentioned above and todetermine which system is more suitable to apply on a school. The building whichconditions were used for this evaluation is Röselidsskolan.A solar heating plant of each system type was dimensioned from the expected andknown conditions of the building. The purpose with the dimensioning was to makethe solar plants replace the ordinary energy source as much as possible.