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1448 Uppsatser om Technical properties - Sida 26 av 97

Vad styr förekomsten av sälg och asp? : en studie av olika beståndstyper inom Hamra kronopark, Dalarna

Aspen (Populus tremula L.) and goat willow (Salix caprea L.) are two important tree species in the aspect of nature conservation. Due to the elimination of forest fires, a former negative attitude towards deciduous trees in forestry and a strong herbivore pressure, these tree species have been negatively affected during the last fifty years. The aim of this study was to investigate whether the occurrence of aspen and goat willow could be related to either human impact or to site properties, such as ground moisture and vegetation type. A side study included an inventory of a number of cyanobacterial tree lichens on aspen and goat willow in order to try to relate the occurrence of these lichens species to stand history and stand properties. The study was performed in Hamra State Forest in northern Dalarna. Nature reserves were compared with stands in managed areas.

Luft/luftvärmepump : - Med möjlighet till återvinning

Sweden has long had access to low electricity prices due to the wide availability of hydro and nuclear power. This has now changed because of today's rising electricity rates resulting in increasing heating costs for properties, especially in the properties with electric heating systems."Ankaret" is a parish for "Svenska Alliansmissionen", which is located at "Gullbrannagården".The parish has installed electrical radiators and an exhaust ventilation system that makes the energy demand high due to the large ventilation flows. The building was built as the price of electricity was still low and would reduce energy use today by combining its heating system with an air/air heat pump. The heat pump delivers more heat into the room than the electrical energy that it uses. This lowers the electricity needs.

Begreppet hållbar utveckling : Dess historia samt internationella och lokala användning

This thesis is a case study of the search function on the University of Uppsala?s web site. The search function in this study was chosen since it exists on a large and complex web site and there were apparent lacks in the old version of the search function. The thesis highlights some of the problems that can appear in the development of a search function on a local site. One interesting find is that one of the most difficult issues is organizational and not technical.

Att förmedla en känsla

This thesis has its background in my curiosity of music and emotions. How can one find the technical way of bringing out emotions in music? I have worked with passages in music that I believe that the composer intended us as musicians to perform. This thesis presents a collaboration of three chamber musicians working with and performing Brahms Clarinet Trio, the first three movements. I?ve studied different theory analyses by several teachers and worked with the trio to apply it onto the performance and our interpretation of the work.

Termomekanisk utmattning av Sanicro 25 : Materialmodellering med finita elementmetoden

The report aims to describe the austenitic stainless steel Sanicro 25 from a thermomechanical point of view. The thermal and mechanical properties of the material make it suitable for use in coal ? and thermal power plants. By the use of Sanicro 25 it would be possible to bring the efficiency of these plants up while bringing the carbon emissions down.A material model is created from material testing and validated through simulation in the finite element software Abaqus. The model that has been derived describes the material behavior during loading and stress relaxation for the first cycle in a thermomechanical fatigue test well.

MoPho -enkla lösningar för SMS och MMS

Our project is divided into two parts, one production and written report. The main focus was the production part, were we used PHP to create simple solution for handling SMS and MMS with direct communication with the mobile operator server. We communicate with sockets and can handle CIMD2 and MM7 protocol. To get our components easy to use we have created two classes to handle SMS and MMS. To demonstrate our technical platform we created a website were you can create an account.

Säkerhet i öppna WiFi-nätverk. En studie om hur användares medvetenhet om säkerhetsrisker vid interaktion med öppna WiFi-nätverk kan ökas

Public WiFi networks is one of the dominant technologies for users to get public internet access. The problem is that the networks are designed for accessability rather than security ? a problem users seldom are aware of. Users who carelessly access WiFi networks may reveal sensitive information which, among other things, can lead to an identity theft. Previous research suggests that users must be educated and informed about the risks they incur, but not how this should be done.

Undersökning av svetsegenskaper för svetsning med rörtråd kontra homogen tråd

Welding is a common method for joining of metal or plastic construction parts. This report describes several different weld methods in general terms. The report focuses on the GMAW method, specifically MAG welding.A case study has also been performed for the company Wenmec. The task received from the company was to compare the mechanical properties of joints welded with the tube electrode called Nittetsu SM-3A and joints welded with the homogenous electrode called ESAB Aristorod 12.63. Both types of weld joint were welded with the MAG method with an Argon based shielding gas with 18% CO2.

Studie av nötnings- och friktionsegenskaper vid höga temperaturer i Kanthal APMT

During this master thesis, wear and friction properties for the high-temperature alloy Kanthal APMT were studied. The results were also compared to 253MA. The initial tests showed, among other things, that the surface fineness of the muffle tubes matters in real applications like conveyor belts. A 253MA-sample wear-tested against a 253MA-tube showed lowest wear at 900°C while a pre-oxidized APMT-sample wear-tested against a APMT-tube had the lowest mean value of the friction force at 1100°C, compared to all other tests..

Hur dagsljusinsläppet påverkar upplevelsen av ett rum

The background to this report is based on how architectural art through timesbeen treating daylight with greatest precision to take advantage of its good quality,and how the technical revolution with artificial lighting affects our way of workingwith daylighting today.The purpose of the study is to contribute to the knowledge how the daylightopening affects the perception of a room. The aim is to clarify how proportionsand placement affects how the incident light occurs in the room and how thataffects on how the room is perceived. The study is meant to be used by lightingplanners, and in terms of pleasantness, be able to create the best possible daylightenvironment..

Ljusspridningsvariationer i finpapperstillverkning

The purpose of this Master's thesis is to find possible explanations of variation in light scattering in a fine paper. Samples were collected from each second tambour during a time period of two weeks from a paper machine at MoDo Paper, Husum. Two data sets, consisting of 20 and 95 observations, were selected for extensive analysises of tensile and structual properties. The data was evaluated with multivariate data techniques using the programs Simca and Extract. The results of PCA- and PLS- analysises pointed out 3 of 52 variables as important for the variations in light scattering.

Camp Vamp - Att ljussätta en dansföreställning med skiftande förutsättningar

I work on a lighting design for a dance performance to be on tour. A lighting design adapted for three different conditions was made: - One comprehensive where I allow myself a great deal of creative freedom, adapted for the stages with major technical conditions. - One smaller version for stages with less equipment and with less time for preparation on site. - One design for very simple conditions. I also examine the specific differences between typical theatrical lighting design and typical dance lighting design, and the best way to prepare for the hands-on stage design phase..

Kons fertilitet : kostnader och åtgärder

To get a good economy on the dairy farms the fertility control of heifers and cows is a crucial factor. It is also important to know which key parameters that should be tracked. In this work well established routines for heat detection have to be applied. When the dairy farmers use technical aid in estrus control it is important not to forget that technical aids can not replace the human eye. Approximately 50 % of all opportunities to inseminate are missed because clear signs of estrus have not been displayed and/or recorded. The cattle fertility has been declining over recent years. During the same time the cow?s proceeds have increased, consequently applying a higher pressure on the cow and the manager.

Deaktivering av metanisering katalysatorer

A titania-supported nickel catalyst was prepared and tested in methanation in order to evaluate its catalytic properties (activity, selectivity and specially, activity loss), and compare it with an alumina-supported nickel catalyst.The titania-supported catalyst did not only show higher stability than alumina, but also presented a different cause of deactivation, carbon formation. In addition, a kinetic model was obtained for the titania-supported catalyst, and a study of the effect of different operating conditions (temperature, composition and partial pressures of synthesis gas and water) on the deactivation rate and carbon formation of this catalyst was performed.

Urban Vindkraft : ett nytt element i bebyggd miljö?

This paper aims to explore the phenomenon urban wind energy, its visual effect on built environment and the factors that affect the opinion towards new elements in the city. A place study of the city Gävle serves as a complement to the theoretical part of the paper. The theoretical discussion opens with an account for the technical and economical conditions of urban wind energy. It presents the technical basics, different types of turbines and a discussion occurring wind related techniques in built environment. Today, the knowledge of how the wind moves and acts in the rural landscape is quite good.

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