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625 Uppsatser om Jet penetration depth - Sida 1 av 42

Effekter av bearbetningsdjup i plöjningsfri odling

In Sweden, reduced tillage usually means non-inversion tillage, where primary tillage is carried out using chisel ploughs or disc implements. Primary tillage method is mainly determined by the desired soil loosening and the handling of soil residues. The effect of tillage depth was studied in field experiments in Skåne, Väderstad, Uppsala, Örebro och Västerås in different crops; spring oilseed rape, spring wheat, winter wheat and spring barley.The experiments generally had a randomized block design with the treatments mouldboard ploughing, deep chisel ploughing and shallow chisel ploughing, in some cases also shallow discing and no-tillage. In the experiments the following parameters were determined: seedbed properties, saturated hydraulic conductivity, penetration resistance, number of emerged plants and crop yield (all parameters were not determined in all experiments. Root growth and draught requirement were determined in two separate studies. There were no significant differences between tillage depths in non-inversion tillage in seedbed properties, plant emergence or root development.

Optisk undersökning av dieselsprayer från en höghastighetsroterande insprutare

There have been changes in Earth?s climate system on both global and regional scale since the pre-industrial era and some of these changes are due to human activities such as the combustion of fossil fuels. This calls for the development of engines with a higher efficiency and less harmful emissions. One interesting concept is the Homogeneous Charge Compression Ignition (HCCI) engine, which has the advantages of potentially low emissions combined with high efficiency. However, HCCI with diesel fuel requires a relatively long fuel/air mixing time to ensure a "homogenous" charge.

Anva?ndning av markfuktighetskartor fo?r sta?ndortsanpassad plantering

Digital depth-to-water maps can be produced from a digital elevation model (DEM). Then GIS- based algorithms are used to calculate water flows and the depth-to-water index classes dry, fresh, moist and wet. The purpose of this study was to investigate the possibility to use depth- to-water maps for site adapted planting.The results showed that use of depth-to-water maps for site adapted planting, roughly halved the proportion of improperly planted surfaces from an average of 9 % to 4 %. The variation in the values of proper surface decreased and the result became more even.. In addition, more pine than spruce was incorrectly planted.

Experimentellt vidareutvecklad modell för dimensionering av skadebegränsandeåtgärder mot RSV-penetration vid ammunitionsröjning

Vid röjning av RSV-ammunition saknas idag adekvat beslutstöd för att dimensionera skadebegränsande åtgärder mot jetstrålens verkan. I uppsatsen vidareutvecklas en beräkningsmodell som författaren tidigare föreslagit. Syftet är att skapa ett verktyg som kan införas i ammunitionsröjningsverksamheten.Fullskaliga skjutförsök har genomförts för att klarlägga inverkan av förhållanden som är typiska vid ammunitionsröjning; en skyddskonstruktion byggd av sandsäckar och med ett långt detonationsavstånd till röjningsobjektet. Försöksresultatet visar att den grundläggande hydrodynamiska penetrationsteorin inte är användbar för dessa förhållanden. Vidare ger sandsäckskonstruktionen signifikant bättre skydd mot jetstrålen än en homogen grusbädd.Genom störningsanalys har känsligheten hos de enskilda parametrarna i beräkningsmodellen för verksamhetstypiska fel utretts.

Djup icke vändande bearbetning i sockerbetsodling :

A field experiment was carried out in 2006 to investigate the effects of deep rotary cultivation on sugarbeet growth. The background to the experiment was a 2005 study showing potentially higher yield, higher cleanness and higher sugar content when primary tillage was carried out to 35 cm depth with a rotary cultivator. On four field sites in Skåne (L:a Isie, Ädelholm, Stävie and Vragerup), five different treatments were compared: mouldboard ploughing in the autumn to 20 cm; mouldboard ploughing in the autumn to 20 cm + rotary cultivation in the spring to 35 cm; rotary cultivation in the autumn to 35 cm; rotary cultivation in the spring to 35 cm; and mouldboard ploughing in the spring to 20 cm. The rotary cultivator used in the treatments is manufactured by a Dutch company, Imants. The implement cultivates the soil with spade tines fitted on arms that are mounted on a horizontal rotating PTO-driven axle. Beet plants were inspected and yield determined in the experiment, and three soil parameters were examined: penetration resistance, water infiltration and infiltration of blue dye. Root shape was also examined. The site at Stävie was not harvested due to poor beet establishment. At the other sites, the highest yield was found when the soil was rotary-cultivated in the autumn.

Habitatpreferenser hos tjockskalig målarmussla (Unio crassus) med avseende på vattendjup och beskuggning.

The thick-shelled river mussel (Unio crassus) is a red listed species classified as Endangered (EN) and is also considered within the Habitats Directive. The distribution in Sweden is fragmented and it is mostly occurring in the south eastern parts. We investigated the presence of Unio crassus in a section of the stream Storån, Östergötland County, from Falerum to the inflow into Lake Åkervristen. The environmental parameters investigated were water depth, bottom substrate, shading, water velocity and the slope over the water surface. In this thesis I have focused mainly on water depth and shading, comparing sites with and without mussels.

Ytstridsfartygs ballistiska skydd mot finkalibriga projektiler

This paper is about the extent to which simplified penetration calculations ofsmall-caliber projectiles is a useful tool for assessing the physical protectioncapability. The work should be seen as an attempt to create an accessible tool inthe form of a simplified equation that allows for a better and safer use of thenaval vessels. The tool will also be used at different levels so that decisions andinstructions could be clearer.Performed calculations show a very limited capacity of a ship's basic design interms of physical protection against the use of small-caliber projectiles.How do we know that the calculations correct? By verifying the calculations withpractical shooting tests, a substantial condition to answer the question will becreated. To shoot against a material with two different thicknesses estimated toproduce perforation and non-perforation is a good approximation of the equationusability in the context..

Kol-14 datering : En litteraturstudie över hur kol-14 isotopen används för datering, samt utveckling och tillämpning av djup-åldersmodeller inom naturgeografin.

This literature study concerned the use and function of the radioactive isotope carbon-14, as a dating method of organic material, within the scientific field of physical geography. In this report it is presented the need of atmospheric calibration curves and the development of these as a necessity to translate carbon-14 years to calibrated calendar years. A number of common age-depth models that is used to give an approximation of an accumulation sequence and its related dates over the actual time period in different natural archives is presented and discussed. Different problems that commonly occur when age-depth models are utilized as for instance reservoir effects, contaminations or other age deviations are addressed and analyzed. The software CLAM in presented and discussed and was also used to produce age-depth models.

Framgångsfaktorer på bredbandsmarknaden ? vad utmärker en framgångsrik marknad?

This master thesis is written at the Royal Institute of Technology during the spring and summer of 2008.The assignment was to investigate what factors on a broadband market determine how well it performsin terms of how many people have access to broadband. These are the factors that determine whetheror not a country or market will be able to achieve a high broadband penetration. The purpose of thisthesis was to establish a better understanding for what a market should look like or how a strugglingone can be complemented in order to succeed.As a foundation for this investigation, a group of benchmark countries were chosen and evaluated. Inaddition to this, a group of, developing MENA2-countries were chosen and evaluated. Finally, interviewswere performed with some of Sweden?s leading internet service providers, the regulatory agency andinfrastructure company, Skanova.Among the benchmark countries were Sweden, France, Canada, South Korea and Japan.

Effekt av sönderdelningsgrad och planteringsdjup på uppkomsten från rhizom av Tussilago farfara :

Tussilago farfara, coltsfoot, is a troublesome perennial weed with deep lying rhizome, which can vegetatively generate new plants. The mechanical control of coltsfoot that is used today, "starvation", which consists of several cultivations of the soil, which fragmentises the rhizome. This results in production of new shoots, which leads to depletion of nutrient resources; as long the new plant is not allowed to establish. However, very little research has been done to investigate how the starving technique affects the regenerative ability of coltsfoot. The purpose of this experiment with coltsfoot was to investigate how fragmentation and burial depths affect the time of emergence, number of emerged shoots per rhizome fragment, number of shoots per node, and if the germination ability within nodes changes during the experiment.

Bättre åtkomst till avverkningstrakter med anpassat marktryck från avverkningsmaskinerna

The global climate-change means increasing mean-temperature and higher precipitation in Sweden, which leads to shorter periods of frozen ground in the forest. At the same time the harvesting machines are getting bigger and more powerful. The forest industry aim at an even wood flow, and the ground damage has to be as low as possible. The two biggest causes for ground-damage is the bearing capacity of the forest ground and the ground-pressure of the harvesting machines. The aim of this study was to find out some rules for the machine choice considering ground pressure, when harvesting on ground with low bearing capacity.A field study, using a Valmet 890.3 forwarder, was carried out where different ground pressures and their effect on the ground were tested on two different types of ground.Additionally, an inventory of damaged harvesting grounds was made.

Medieanvändning för individer som nätdejtar : en kvalitativ undersökning om mediernas roll i olika faser iinteraktionen

AbstractTitle: How does people that meet online communicate? -An qualitativestudy of the media use for individuals that date online.Number of pages: 34Autohor: Malin JanssonTutor: Amelie HössjerCourse: Media and Communication Studies CPeriod: Spring term, January 2010University: Informatics and Media, Media and Communication ScienceUppsala UniversityPurpose/Aim: The aim of this essay is to see if mediea use changesthrogh time in a relationship between individuals that have metonline.Material/Method: Qualitative method with nine interviews divided into two groupsdepending whether the person is an actively dejting online or ifshe has a long term relationship with someone she have metonline.Main results: The use of digital media changes thorugh time in therelationship. The individuals stop using the net dejting whenthey meet someone. The digital medias are stage at the begginingof the relationship. Through time they use a multiple ofdigital medias but they have preferenses and prefers to use thetelephone both when they are communicating positive andnegatvie information.Keywords: Online dating, social penetration, process of getting to knoweachother, communication.

CFD-simulering av kallras från fönster : Konvektorers och nischdjupets inverkan på lufthastigheter i rummet

During cold winter days it is likely that people in buildings with older windows or high glass facades experience thermal discomfort due to cold air down draughts. Earlier work has been aimed at finding analytical methods to predict the speed of the airflow in a room and in practice heating appliances are often placed beneath the windows to reduce the draught along the floor. In a study from 2012 Mohammad Parchami developed a method for estimating the required heating power to counteract the downdraught with such heating appliances. In this study, Computational Fluid Dynamics (CFD) was used to evaluate the usefulness of Parchami?s method and also to examine the potential of adapting the depth of the inward window sill as a means of decreasing the down draught.

Beräkningsmodeller för riktad sprängverkan vid ammunitionsröjning

I arbetet görs en ansats att utveckla verktyg för dimensionering av skyddsåtgärder vid röjning av RSV-ammunition. Till skillnad mot övriga verkansformer så saknar ammunitionsröjaren idag beräkningsmodeller eller annat adekvat stöd för fastställande av maximalt riskområde respektive för dimensionering av skadebegränsande åtgärder vid röjning av ammunition innehållande riktad sprängverkan.Arbetets fokus utgår från den militära nyttan med ett sådant verktyg, då en anpassning till röjningsverksamhetens informationstillgång, tidsförhållanden, arbetsmetodik och tekniknivå är direkt avgörande för om ett verktyg kan anses ändamålsenligt eller ej.Resultatet utgörs av förslag på två kompletta verksamhetsanpassade verktyg. Det första i form av en beräkningsmodell för dimensionering av skadebegränsande åtgärder, vilken kombinerar RSV-strålens penetrationsförmåga med detonationsavståndets inverkan. Det andra verktyget är en enkel modell för bedömning av det maximala riskområde som en RSV-stråle kan ge upphov till, vilken baseras på det dimensionerande strålsegmentets ballistiska bana..

"Enjoy the Ride. I know I am" En studie i maskulinitet

En studie i maskulinitet som det skildras i den pornografiska filmen Pirates..

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