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574 Uppsatser om Temperature gradient - Sida 7 av 39

Varmsmidning av aluminiumlegering 6026 T9 : Warm forging of aluminum alloy 6026 T9

In this project forging of aluminum alloy Al 6026 T9 has been performed in the temperature range of 400 °C ? 470 °C. The alloy which was in the shape of a cylindrical billet was formed in a press with the aim of analyzing the effect of different forging temperatures and required press load for optimal die filling. The component?s dimensions were later measured and compared to a reference piece.

Vinterförvaring av Pelargonium x hortorum :

There are many different recommendations on how to keep pelargoniums over winter, but most of the recommendations suggest ?the higher the temperature, the more light and water the pelargonium needs?. The purpose with this paper is to try to explain the best and the worst results that are achieved with different storage alternatives of zonal pelargoniums. The results are based on an orientating investigation carried out in January-February, and a questionnaire that members of the Swedish Pelargonium Society answered to. Both the orientating investigation and the questionnaire showed that zonal pelargoniums are best stored light and cold but frost free. They should be irrigated according to their needs which is when the soil is dry, about every second to third week. Zonal pelargoniums are very resistant to drought and can survive without water for at least 44 days, both when kept under light and cold as well as under light and warm.

The importance of shade for dairy cattle in Sweden.

Today, there are no regulations saying that cows must have access to some kind of shelter at pasture during the summer. In more tropical countries, it is well-known that dairy cows might suffer from heat stress when exposed to sun and high temperatures. The well-being of the cows is thereby reduced and the production may also decrease. In Sweden, no research has been done in the area and therefore it is now a clear need of improved knowledge.The purpose of this study was to investigate the importance of shade for dairy cows in Sweden. The behaviour of 30 cows was examined to see any differences between cows with access to shade and cows without access to shade.

Epiphytic lichen flora in a boreal forest chronosequence

Epifytiska lavar utgör en viktig del av floran i den boreala zonen. Några miljövariabler är kända för att styra artrikedomen och artsammansättningen av epifytiska lavar på beståndsnivå, såsom träddiversitet, beståndsålder, fuktighet och trädens barkstruktur. Skogsbränder utgör den viktigaste störningen i boreala skogar men studier på brandeffekter på epifytiska lavar är mycket få. Detta arbete undersökte artrikedomen, diversiteten och artsammansättningen av epifytiska lavar på basala delar av björkar längs en gradient av 30 skogsbeklädda öar som skiljer sig i storlek och brandhistorik i den norra boreala zonen i Sverige. Målet med studien var att undersöka hur lavfloran påverkades av östorleken och miljövariablerna längs gradienten.

Konstruktion av Laborationskort med PIC-processorn

In this report you can get a complete instruction about how to build your own development system for the PIC-processor. This card will be used for laborations for the students at LITH-ITN. With this card you can send new assembler codes (new instructions) down to the microprocessor via the Serialport on your computer. Then the new instructions for the microprocessor will start to execute. We made a solder paste stencil at Campus Norrköping solder paste stencil laboratory.

Termisk hantering av litium-jon- batterier i elektriska drivsystem

The automotive market is currently undergoing a historical change where stricter emission legislations and ever increasing fuel costs have intensified the search for effective alternatives to the conventional internal combustion engine, which has resulted in a substantial trend towards electrification of powertrains. Storage of electrical energy is the fundamental component in this technology where the lithium-ion batteries are currently considered as the most appropriate solution. Lithium-ion batteries, however, as other types of batteries, can only be used efficiently and durably within a specific temperature range.This Master thesis has been carried out in collaboration with Electroengine in Sweden AB, situated in Uppsala, which has an ongoing project regarding development of a modular battery system for electric powertrains. The project is at a stage where an initial prototype has been developed which provides the foundation for this thesis. The study has addressed the battery system performance from a thermal perspective, in order to validate the ability of the system to create a thermally serviceable environment for the lithium-ion battery cells.

Värmeöverföring i bergvärmesystem : En numerisk analys av den ringformade koaxiala borrhålsvärmeväxlaren

The borehole heat exchangers of today suffer from poor thermal and hydrodynamic performance. The purpose of this thesis is to improve the performance of ground source heat pump systems and thermal energy storages by increasing the energy efficiency of the borehole heat exchangers. For this reason, the annular coaxial borehole heat exchanger (CBHE) has been analyzed. This type of heat exchanger is interesting in terms of both thermal and hydrodynamic performance. A model has been set up in the program Comsol Multiphysics in order to investigate the heat transfer characteristics along the borehole.

Cassava as an additive in biomass fuel pellet production :

In this study, the effects of using fine milled cassava stems as an additive in biofuel pellet production was compared to the effects of refined starch addition. The bulk biomass fuel raw material, to which the additive was added, was a blend of spruce and pine sawdust. An experimental design in the factors cassava/starch content, moisture content and material temperature was used. Measured responses were pellet bulk density, pellet durability, amount of fines, pelletizer motor current, pellet temperature, die temperature and CV for pelletizer motor current (a measure of process stability). Each response was modeled by multiple linear regression (MLR).

Safe retrieval of nutrients to improve food security

Safe retrieval of nutrients from human excreta to fertilize crops in order to gain adequate yields will increase food security and sustainability in agriculture areas with nutrient-poor fields. Safe and nutritious food will meet the dietary needs of the individual which promotes public health and the ability of an active life. Human excreta should be considered as a resource instead of being assumed as waste. Human faeces and urine is excellent fertilizers which may close the nutrient loop if utilized properly. However, sanitation of the excreta is required to prevent disease transmission by reducing the content of gastrointestinal pathogens such as bacteria, viruses and parasites. The objective of this study was to in small scale evaluate the sanitation in a combined liquid compost and urea treatment by monitor the inactivation of bacteria and viruses at the combination three start temperatures, 45, 40 and 35 °C, and three additions of urea, 0.5, 0.75 and 1 % and reference, 0 % urea addition.

Termografisk undersökning med samtidig analys av rektaltemperatur, hjärtfrekvens, psykiska reaktioner och specifika blodparametrar av häst som behandlats med vibrationsboxen Vitafloor :

A number of studies in human medicine has documented positive effects of whole body vibration treatment in humans. The Vitafloor system, witch is based on treatment of horses with vibration, has the purpose to be used in training of healthy horses and as rehabilitation for horses with injuries in their musculosceletal system. The purpose of this study was to analyse what happens with a clinically healthy horse during treatment with Vitafloor. The methods used is mainly thermography before and after treatment, but also blood samples, measurement of rectal temperature, heart rate, clinical examination and observation of psychic reactions has been done. Statistic significant changes in skin temperature in hoofs and fetlocks of front legs has been observed after treatment with Vitafloor. Analyzing of the blood samples showed a tendency for decrease in Kalium, and two of the horses had changes in CK. No negative effect has been observed with the treatment of horses with Vitafloor, and the horses seems to like the treatment. .

Olika naturliga kvävekällors inverkan på värmeutvecklingen i varmbänkar

Uppsats för avläggande av filosofie kandidatexamen iKulturvård, Trädgårdens hantverk och design, 15 hp, 2015.

Konvertering från luft till vätskekylning av elektronik

A Swedish electronics company wants to make the cooling of one of their electronic components more efficient. They propose that a retrofit liquid cooler is the way to achieve this goal. The current air cooling has high energy cost due to the high amount of power needed to power fans and heat exchangers. Using high volumes of air for cooling also leads to noise pollution. The conversion from air to liquid cooling would possibly make the operation of the electronics more cost efficient and less noisy.The purpose of this project is to theoretically evaluate different concepts of drawing the heat generated by the electronic component in to a fluid, using numerical calculations in Matlab and FEM simulations in ANSYS.

Restspänningar i arc-förångade (Ti(1-x)Al(x))N ytskikt

This report is the written documentation of a project work carried out at the Division of Engineering Materials at Luleå University of Technology in cooperation with Seco Tools AB. The project deals with the analysis of residual stresses in Ti-Al-N thin film grown on WC/Co cutting inserts. The composition of Al varied from 0% up to 75%. Increasing the Al content in the Ti(1-x)Alx N compound improves the compressive residual stresses even after annealing of the material. The experiments have been performed in a high temperature x-ray diffractometer (HTXRD) where the interplanar atomic spacing was determined in-situ and subsequent converted into stresses.

Stopover duration and field site selection by whooper swan (Cygnus cygnus) at Lake Tysslingen, Sweden

The aim of this study was to increase the knowledge about whooper swan (Cygnus cygnus) ecology to enhance the ability to predict and also to prevent the crop damage they cause. The largest proportion of damage in Sweden has been reported at stopover sites during spring migration in February, March and April. Therefore, this study focused on an important stopover site, Lake Tysslingen, situated in south-central Sweden. Specifically, the relation between the duration and period migrating swans stage at the stopover site and mean temperature (measured at three different weather stations) for the years 2001-2010 was studied. Furthermore, the swans´ selection for certain fields in relation to field type, distance to roosting site, a supplemental feeding site and forest edge within agricultural land surrounding the lake was analyzed.

Gröna värden i Lidingö och Lomma : inventering av upplevelsekvaliteter i grönområden som metodi kommunal planering

The aim of this study was to increase the knowledge about whooper swan (Cygnus cygnus) ecology to enhance the ability to predict and also to prevent the crop damage they cause. The largest proportion of damage in Sweden has been reported at stopover sites during spring migration in February, March and April. Therefore, this study focused on an important stopover site, Lake Tysslingen, situated in south-central Sweden. Specifically, the relation between the duration and period migrating swans stage at the stopover site and mean temperature (measured at three different weather stations) for the years 2001-2010 was studied. Furthermore, the swans´ selection for certain fields in relation to field type, distance to roosting site, a supplemental feeding site and forest edge within agricultural land surrounding the lake was analyzed.

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