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164 Uppsatser om Modelling - Sida 7 av 11

Chewing behaviour of growing cattle

Chewing behaviour includes both eating and ruminating activity. Chewing behaviour is of great importance for the feed intake as through the action of chewing (i.e. eating and ruminating) animals mechanically process the forages in small particle sizes and prepare the food for digestion. As cattle grow the chewing behaviour changes along with increasing body weight and chewing efficiency is increased. The aim of this thesis was to review the available scientific literature in order to describe chewing behaviour in growing cattle, as well as the factors that affect this behaviour.

Framtagande av kravspecifikation för standardsystem

There are several methods and models within the areas of software engineering on how to proceed during a software development process. For each of these methods and models there are benefits and drawbacks, depending on how you choose to look at them. A difference of principle between the different models is that they either advocate iterative development or not. In parts of software engineering one makes use of different methods depending on which is most fitting in a specific situation. There are several methods on how to recieve more qualitative data from the end-users during the requirement collection, but the reappearing pattern is still user centric participation, which means that the user participates more actively in part of or the entire development process.

Förändring av nitratläckage och växtproduktion från låglänt jordbruksmark vid en ny reglering av vattennivån i Mälaren

The water level of Lake Mälaren has been regulated since the 1940?s. A recentinvestigation suggests that the current regulation needs to be adjusted in order toprevent a decline in water level, salt water from infiltrating from Lake Saltsjön,and risk of floodings. In addition to these preventions, the new regulation couldpotentially effect the natural environment and agriculture practices in the lowlands that surround the lake. The new regulation proposal calls for an increase invariations in Mälaren?s water level during seasons, while the annual mean waterlevel will remain the same.

A quantitative analysis of global kiwifruit trade

New Zealand is currently the third largest global producer of kiwifruit and thus plays an important role in the international market. Exports of kiwifruit are also of significant horticultural value for New Zealand and in 2007 the kiwifruit industry accounted for export values of NZ$790 million. The global kiwifruit market has experienced substantial changes in recent years and is likely to change significantly in the near future due to developments in production sources, adjustments to trade policy settings and shifts in consumer preferences. The New Zealand kiwifruit industry needs to consider what the impacts of these changes might be so that future strategies can be constructed effectively. Little quantitative Modelling has been done in New Zealand to consider the impacts of changes to the global kiwifruit industry. The major contribution of this research was the development and calibration of a kiwifruit industry-specific partial equilibrium trade model. The model was then used to examine the impacts on New Zealand producers of these trade-related changes in the global kiwifruit market.

Förslag till nytt utförande av fasta ställbara fläkthjul

Examensarbetet går ut på att frambringa några principkonstruktioner till axialfläktar med fasta inställbara skovlar åtFläktWoods. Fläktarna det rör sig om är stora industrifläktar med en diameter mellan en och fem meter, som används för atttill exempel transportera ner luft i gruvor. Endast förslag till principkonstruktioner tas fram och ej en färdig produkt, syftetmed rapporten är i första hand att ge FläktWoods konstruktörer ett annat synsätt på problemet. Två olika delar av fläktenundersöks, dels fästet av skoveln på hjulet, dels själva hjulet i sig. Tillvägagångssättet är att från formulerat problem tasförst några förslag fram, de utvärderas sedan och de bästa går vidare till nästa steg.

Konstruktion av säkerhetslagerför svänghjul

This thesis is the result of the investigation and solution of a mechanicalproblem regarding flywheel malfunctions. A flywheel is, in short, a devicethat relies on a rotating object?s moment of inertia to store energy overshort time spans. This project is part of the development of a fourthflywheel prototype at the division for electricity at Uppsala university,which uses magnetic levitation to keep a hollow cylinder rotating at veryhigh speeds inside a vacuum chamber. Should the magnets fail however, orsome other error occur that leads to an uncontrolled state of rotation, thecylinder needs to be stabilized mechanically by a device usually referredto as ?back-up bearing?.

Undersökningsmetodik för klorerade lösningsmedel i marken

Chlorinated solvent are volatile organic substances that can be harmful for humans and for the environment. Examples of common chlorinated solvents are perchloroethene, PCE, and trichloroethene, TCE. Chlorinated solvents appear as contaminants in soils primarily where they have been used as washing fluids in dry-cleaning facilities or as degreasers in metal industries. Chlorinated solvents are DNAPLs (dense non-aqueous phase liquids), which means that they are not easily dissolved in water and that they sink to the bottom of the aquifer. Adsorption to soils is low so chlorinated solvents are mobile in soils.

UML som stöd vid småskalig utveckling av ett inbyggt system

This project aims at investigating if the use of UML as a support to small-scale development ofan embedded system is relevant. The investigation is conducted by using UML during the initialphase of the development ofTelfafill, a filling machine by the company ?Telfafill AB?. The aimof the development of Telfafill is to separate the user interface from the control unit. In additionto this main objective, Telfafill AB would like possible changes to, and additions of,functionality of the filling machine to be investigated.Within the boundaries of this project, the development of Telfafill reached a full requirementspecification of the proposed system, and contact was made with potential external developers.No prototype construction had been started when the project ended.

Solar energy on Swedish pig farms : a sunny story?

In Sweden there is a large interest in renewable energy but the market for solar power is still small compared to other countries such as Germany. Here many farmers produce their own electricity. The Federation of Swedish farmers have acknowledged the potential for Swedish farmer to produce electricity and there is an interest among the farmers. The agricultural branches in Sweden most suitable for solar power are pig production and poultry due to the even electricity need throughout a year. Swedish pig farmers are going through a period of unsteady profitability which makes it interesting to see whether producing their own electricity can affect the economic situation.

Beskrivning av systemfunktioner i kärnkraftverk med hjälp av objektorienterat modelleringsverktyg

In order to facilitate design and maintenance of such a large and complex site as a nuclear power plant, all system functions must be described in a stringent way. In the past, these descriptions consisted of text documents and logical diagrams, but today there are an increasing number of object-oriented programs available on the market which might be used for this purpose. This Master Thesis has made a closer study of one of these programs named Rational Rose. The principal of the program is to facilitate software design and development, not to create models of plants. However, using the program the same way as developing software, specifying actors then gradually extend the model with use cases, use cases diagrams etc, the same methods can be used when Modelling plants.

Modellerade och uppmätta kväveflöden i energiskog som bevattnas med avloppsvatten

The aim of this essay was to study the nitrogen flow in two willowplantations, at different locations in the south of Sweden, that wereirrigated with sewage. The study was also performed to compare thedifferences in nitrogen flows between two years, 1998 and 1999. The studywas made in three parts. First, the denitrification activity was measuredusing the acetylen inhibition method. Second the nitrogen flow, as well asthe water- and heat flows, were modeled through the SOIL-SOILN-modelThird; the nitrogen flow was calculated to compare with the results fromthe model.The results from the measurements were then compared with the resultsfrom the SOILN-simulations to detect differences in the denitrificationrate.

Framtagande av kravspecifikation för standardsystem

There are several methods and models within the areas of software engineering on how to proceed during a software development process. For each of these methods and models there are benefits and drawbacks, depending on how you choose to look at them. A difference of principle between the different models is that they either advocate iterative development or not. In parts of software engineering one makes use of different methods depending on which is most fitting in a specific situation. There are several methods on how to recieve more qualitative data from the end-users during the requirement collection, but the reappearing pattern is still user centric participation, which means that the user participates more actively in part of or the entire development process.

Samband på individnivå mellan akuta klövskador och cellhalten i mjölk hos mjölkkor :

The purpose of the present study was to investigate the cow-level association between acute hoof lesions and the somatic milk cell count in dairy cattle. Cows from three loose-housed Swedish dairy herds were enrolled in the study if they had an acute hoof lesion treated by a veterinarian or professional hoof trimmer during the preceding year, according to farmer records. Studied lesions were sole ulcer, dermatitis, interdigital necrobacillosis and hoof abscess, in each case causing lameness. For each hoof-diseased cow, 0 to 3 healthy cows were included, matched with respect to herd, breed, parity and lactation stage. Cell counts were obtained from monthly test recordings from one month before to three months after the hoof-lesion diagnosis, and log-transformed.

Analys och förbättring av en mätenhet för laddning av elfordon

Reducing the CO2-pollution, resulting from the combustion of fossil coal for energyproduction, is important to affect environmental changes. One way to achieve a reductionis to use the oxy-fuel technology. The technology uses O2 and re-circulated flue gasduring the combustion which results in a flue gas mainly consisting of CO2. The flue gascould then be compressed and stored without environmental effects. A problem thatfollows from the compression is the risk of acidification in sensitive parts of the process.Acidification can occur because of reactions following from the contact of condensedwater and sulphur- and nitrogen-oxides which are also present in the flue gas.This report compiles and evaluates the basis of a scientific unit with the purpose ofexploring the possibilities of extracting impurities of SOx and NOx from the flue gases.The dimensions of the unit are based on basic conditions, defined for an existing oxy-fuelprocess at Chalmers, and on the results of computer Modelling.

Simulering av vindkraftverk och närliggande elnät vid Risholmen i Göteborg i SimPowerSystems

With background in the rapidly growing need to find solutions for sustainable energy production and the increasing interest for wind power, this report was written. With take-off point from the wind power plant Big Glenn, which has been built in the harbour of Gothenburg, a model of the adjacent power grid has been created in Simulink/SimPowerSystems. Parameters for the power grid and its components has been provided by Göteborg Energi Nät, that has also been the supplier of measurement data of produced power, the power need from loads in the vicinity, voltage levels, current values and also the variation of power factor at the wind power plant.The SimPowerSystems model has been used to perform simulations of power flow in the grid. These simulated values have then been compared to the measured values to verify the functionality of the model. Further, the model has been used to perform simulations of a grid fault, which causes a voltage drop.

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