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574 Uppsatser om Temperature gradient - Sida 10 av 39
Koldioxidavgång vid ekologisk odling på organogen jord
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.
Människovana grävlingar som testdjur för grythundar. En studie om hur grävlingars beteende och fysiologi påverkas av hundars aggressivitet
In Sweden live badgers are used in tests in order to train and prepare earth dogs for hunting underneath ground. This has for several years causeddebate concerning the welfare of the badgers. It is questioned whether the purpose of the dog training, i.e. to reduce injuries in both dogs and prey, is worth the suffering that is reflected on the badgers. The aim of this investigation was to study 1) stress levels in badgers when used in earth dog training, 2) if the stress load differs when the badgers are exposed to dogs with varying aggression levels (low, moderate, high).
Att spela in tramp i studio: En studie om studioinspelning av fotsteg i snö
The complex sound of someone walking in snow aren't easy to create in a studio. The best way to get the sound is to go out on a surface with real snow and record the footsteps there, but it is a complex procedure to get the right sound on the snow because snow sounds different in various temperature and various kinds of snow. It is important to find the right kind of snow to get the right sound on the foot steps. In a studio, the foley artist can create the sound of footsteps in snow by walking on different kind of material, like potato flour, coarse salt or corn flakes, the question is how realistic this materials sounds and what temperature on the snow they sound like. The results shows that the real snow (warm and cold snow) sounds most realistic and the potato flour sounds like warm and wet snow, the corn flakes some think sounds like cold snowwhile others think that it doesn't sound like snow at all and the coarse salt sounds like snow when it is around -10°C in the air, they all sounds similar in realism compared to each other.
Betongpelare och brand : En utvärdering av 500 °C isotermmetoden
At the beginning of 2011, Sweden started using the European rules for structural design, the Eurocodes, instead of the previous national rules. In both the previous rules and the Eurocodes, it is possible to dimension concrete columns using tabled values. However, the required cross section measurements have increased considerably. Moreover, it is possible to dimension concrete columns using calculations, however, this is unusual.The development of a fire in a fire cell can be divided into the growth stage, the fully developed fire and the cooling phase. The duration of each phase, as well as the temperature, is dependent on a number of factors, e.g.
Effektivisering av lagringsplatser. Ett förbättringsprojekt på Mekpart AB
Aeroseum is an aviation museum located in an old military underground hangar. The ventilation system in the hangar is designed for the military purpose of the hangar. This design includes a solution with air flowing through the space between the construction of the hangar and the rock surface. The solution is intended to avoid a buildup of inflammable gases. This design leads too high humidity levels in the hangar.
Hydrauliken i Ångersjöns fosforfällor : bestämning av flödesvägar och åtgärdsförslag för optimal fosforbindning vid avloppsrening med reaktiva filter
Discharge of untreated wastewater leads to unnaturally high levels of nitrogen and
phosphorus in rivers, lakes and the sea, which results in unbalanced ecosystems with
eutrophication and lack of oxygen. Part of the phosphorus in surface waters is coming from
on-site wastewater treatment from scattered households with unsatisfactory purification.
Blast furnace slag is a by-product from iron production, and has in laboratory trials showed good phosphorus binding capacity. To test blast furnace slag as a reactive filter media for phosphorus separation in a full scale experiment, a wastewater treatment plant has been built behind the picnic area at Ångersjön alongside the road E4 in central-eastern Sweden. The plant contains two parallel lines, one with blast furnaces slag and the other with Filtralite-P as phosphorus sorbent. Both filters have showed decreasing phosphorus purification effect with time in spite of a low wastewater load.
Oljetemperaturens inverkan på motoroljans degradering i lastbil
The market for heavy duty engines is constantly requiring engines that should be more andmore powerful, while still maintaining low fuel consumption. As a result of increasing enginepower, the engine and coolant temperature increases as well due to insufficient coolingperformance (because of design issues, cost etc.).Also, emission legislations, both current and future, require more and more measures to betaken by engine manufacturers. One way of meeting the legislations is the use of cooled EGR(Exhaust Gas Recirculation), which also lead to increased coolant temperatures.Both these factors also naturally lead to increased engine oil temperatures, the consequencesof which are not thoroughly investigated.This thesis project aims to investigate effects of high temperatures on engine oil degradation,with focus on the greatest degradation process: oxidation. To do this several engine runs havebeen performed on a 310 hp engine with EGR to see what happens to the engine oil in a realengine when exposed to high temperatures. During the tests oil samples have been taken andanalysed for important parameters.As a complement to these engine tests some laboratory oxidation testing have also beenperformed, to be able to compare engine test data with laboratory tests.One goal of the project was to try to formulate an empirical oxidation model, which would beable to predict oil oxidation levels in an engine, given any running parameters.
Betydelsen av hästens hud och päls för reglering av kroppstemperatur i kyla ? vad händer vid klippning och täckning?
The horse is a homeothermic animal and to keep a constant body temperature in winter season is important. Acclimatisation is to provide means for a good thermal insulation consisting of skin, hair, and an outer air layer. The skin covers the horses body and it is composed of three main layers where the top layer of the epidermis consists of dead keratinized cells that are constantly being sheed. The dermis is composed of collagen connective tissue that give the skin its strength. The bottom layer with subcutaneous fat provides a thermal insulation and can be used as an energy reserve in cold weather.
Utveckling och produktion av system fo?r ma?tning samt loggning av temperatur i roterande elektriska maskiner
The purpose of this thesis has been todesign an electric circuit that measurestemperature in three different ways. Asoftware was also designed to record andanalyse the measurments. The result of thecircuit was a PCB with inputs for 42sensors of both surface and non-surfacemeasurments. These all have a maximumerror of ±3°C..
Utvärdering av en ny selektionsmetod för hingstsperma : med avseende på membranintegriteten och membranstabiliteten
Today, equine breeding is based on performance and conformation, resulting in a vast variation in fertility among different horses, with noticeable economic losses as a consequence. The horse breeding industry is therefore in need of methods that diagnose the spermatozoa concerning their quality and provide the best sperm for AI. The commonly used selection methods for sperm today are: centrifugation, where extender is added, the sample is centrifuged and then resuspended; swim-up self-migration; adherence separation; and density gradient centrifugation. However, none of these methods are in used routinely in practice before inseminating mares with fresh or cooled semen.
The aim of this study was to evaluate a new selection method, Single Layer Centrifugation (SLC), and its effect on sperm viability. The viability was analyzed with regard to membrane integrity and membrane stability of ejaculated spermatozoa.
Analys av mätdata från nätstationer
Fortum has in a pilot project installed metering equipment with wireless communication in secondary substations in Stockholm. So far, the collected data are used only in specific projects.This master thesis was carried out at Fortum Distribution AB in Stockholm during 2013. The purpose of this study is to simplify and enhance the use of data in for example network planning process, by giving suggestions on how data can be managed and giving examples of analyzes that collected data can be used for.The electricity meter which Fortum has installed is a EDMI-Mk10A which is set to measure max/average/min values with a one hour time resolution of the following parameters: voltage (per phase), current (per phase) andactive power and active and reactive energy.In order to analyze the collected data an analysis tool is required. During this thesis two customized tools in Microsoft Excel have been developed, one for sorting data and one for analyzing.One aim of the thesis is to show examples of what collected measurement data can be used for. This work shows an example of analysis of active power, power factor, voltage, occurrence of interrupts and the relationship between outdoor temperature and power.This master thesis has among others resulted in the following advice: Expand the number of secondary substations with measuring equipment.
Luftfuktighetens påverkan på konstruktion och klimat i en berghangar
Aeroseum is an aviation museum located in an old military underground hangar. The ventilation system in the hangar is designed for the military purpose of the hangar. This design includes a solution with air flowing through the space between the construction of the hangar and the rock surface. The solution is intended to avoid a buildup of inflammable gases. This design leads too high humidity levels in the hangar.
Konstruktion av patientsimulator för anestesimaskiner
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.
Tvåstegsavvänjning av köttraskalvar med hjälp av nosbricka :
When beef calves are weaned abruptly at 5 to 6 months of age this triggers a strong stress reaction, since the animals have not yet untied the bonds to their mothers or stopped suckling. This is displayed as extensive vocalization and restlessness. Attempts to diminish the negative effects of weaning on sucking calves have been showing varying results.
The study presented here emanates from the observation that when calves are weaned without human interference they are only prevented from suckling, but are still allowed to have social contacts with their mothers. The hypothesis was that calves weaned in two steps would be calmer, gain more weight, and be healthier than animals that were abruptly weaned. To investigate this, 15 calves where weaned in two stages (Group 2), by fitting the calves with nose tags that prevented them from suckling during 5 days prior to the separation of the cows and calves.
En analys av nattliga koldioxidflöden i en boreal barrskog avseende spatial och temporal variation
Carbon dioxide in the atmosphere contributes to the greenhouse effect, which is essential tolife on our planet. Furthermore, it plays an important part of the photosynthesis andrespiration of the world?s organisms. Since the start of the industrial revolution the amount ofcarbon dioxide in the atmosphere has increased exponentially. The main source is theextensive burning of fossil fuels.