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534 Uppsatser om Soil mechanics - Sida 13 av 36
Konstruktion av en fotobioreaktor för odling av alger : ett småskaligt försök
The prevailing food and energy crisis of the world, due to the declining reserves of fossil energy and a never ending rise of consumption, forces us to look into new fields to supply our energy demand. The boom of bio energy is criticized, as food crops are used to provide biodiesel and ethanol and the volumes are ridiculously small to supply world demand. Algae are one of the world?s oldest life forms and exist in many different phyla, providing a great variety to choose from, for different purposes. Cultivating microalgae offer a way to produce energy at great volumes without competing with food production and at the same time the algae offer a way to use our expensive nutrients in a more efficient way, besides this the algae are carbon dioxide neutral since their carbon source can be supplied by the atmosphere and the additional energy required can be supplied by algal oil or other renewable sources.
Modellbygge av mekaniksystem och riktmotorer i stridsvagn 122
This master thesis is one part of a project, called ?StabSim?, with the purpose to develop a simulation model for the align and stabilisation system in main battle tank 122. The origin of this project is that it should be possible to make control analysis without risking any hardware. Besides that it will be easy to change components in order to investigate the behaviour of the system. The report includes modelling of tower and weapon mechanics and also the modelling of the synchronous motors, which control these.
Behandling av konfliktbestånd - problem och möjligheter :
Overdue cleanings have for a long time been an important topic of discussion within the forestry sector. When stands that have not been pre-commercially thinned are reaching the level of commercial thinning, many problems occur in terms of decision-making and economical outcomes. These types of stands are commonly known as conflict-stands.
The work was carried out partly as an interview survey towards representatives from the forest sector and the energy sector, partly as a case study of conflict-stands situated in Böksholm, north of Växjö and in Tönnersjö east of Halmstad. The criteria for the studied stands were that they had to be dominated by Norway spruce and be in a severe status of ?conflict?.
The aim of the interview was to get an overview of the situation today, and also analyse trends in terms of conflict stands.
Gestaltningsförslag för Norbyvreten : från kvarterspark till stadsdelspark
The prevailing food and energy crisis of the world, due to the declining reserves of fossil energy and a never ending rise of consumption, forces us to look into new fields to supply our energy demand. The boom of bio energy is criticized, as food crops are used to provide biodiesel and ethanol and the volumes are ridiculously small to supply world demand. Algae are one of the world?s oldest life forms and exist in many different phyla, providing a great variety to choose from, for different purposes. Cultivating microalgae offer a way to produce energy at great volumes without competing with food production and at the same time the algae offer a way to use our expensive nutrients in a more efficient way, besides this the algae are carbon dioxide neutral since their carbon source can be supplied by the atmosphere and the additional energy required can be supplied by algal oil or other renewable sources.
Plan för multifunktionella buffertzoner längs Vramsån påMalörten AB : s jordbruksfastigheter
To create multifunctional buffer strips along a watercourse in an economically sustainable way requires consideration of many different factors. In this plan we have selected pollutant reduction as the main purpose of the buffer strip. We have also strived to achieve minimal income loss due to reduced production, increased biological diversity, good game preservation that leads to higher income from hunting, aesthetical satisfaction and possibility to profit from available subsidies. This is done mainly to make landowners/farmers more interested in creating buffer strips along water courses.As sand is the dominant type of soil in the area, the water course is less affected by surface runoff compared to if the soil would be clay or some other finer texture. Game preservation and subsidies have therefore been the main factors when establishing the width of the strip, because these require wider buffer strips in some cases.
Laktester för riskbedömning av förorenad mark :
Using leaching test is a way to get a picture of pollutants retention and leaching in a risk assessment on contaminated land. There are several different types of standardised leaching tests today, where the natural leaching processes are speeded up to make it possible to predict the leaching of pollutants. These leaching tests have been developed for waste and there are no specific guidelines on how to judge the results from the tests, when making a risk assessment on contaminated land. This work is an investigation on how to use leaching test in this type of risk assessments. The strengths and weaknesses of the different types of tests are discussed.
Depending on what type of information you want from your leaching test, different types of tests are suitable.
Utvärdering av koldioxidmätaren Vaisala GMP343 samt sambandet mellan grundvattennivå och koldioxidavgång från torvjordar
The research group Soil and Water Management at the department of Soil and Environment at theSwedish University of Agricultural Sciences in Uppsala are studying greenhouse gas emissions fromcultivated peat soils. To measure carbon dioxide emissions from peat soils in the field the researchgroup are now using two portable carbon dioxide meters (Vaisala GMP343). For practical reasons,they plan to acquire a new type of automated field meter. The aim of this study is to evaluate thepresent meters to see how environmental conditions and instrument settings affect the results,which is meant to facilitate the introduction of the new field meter when the meters needs to becompared. As a part of the study the relationship between groundwater level and carbon dioxideemissions from peat soils will be investigated.The evaluation of the two carbon dioxide meters was made by connecting them to one single airtightsystem, with the aim of creating identical measurement environments.
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.
Konstruktion av upprätningssystem för CICLoPE
Today there is no way of measuring or simulating turbulent flow in high Reynolds numberenvironments. The computational power required to simulate these conditions is not expectedto be available for several decades so instead the CICLoPE project aims at solving thisshortage by the construction of a long carbon fiber wind tunnel in which real measurementscan be made. To do accurate measurements it is of importance that the wind tunnel, 0.9 metersin diameter and 110 meters long, is as straight as possible.This master thesis treat the design and construction of a device which may be used to align thetunnel along a reference laser beam. A design is presented which allows the pipe to be alignedwithin about a quarter of a millimeter along its entire length. Contents span over severalscience fields such as physics, mechanics, control theory and electronics.The result is a theoretically correct design.
Kinetisk Keramik
Do ceramics have to be static? This was the question that spurred me into this work, and what kept me working on to achieve the possibility of motion in my ceramic objects. By combining the knowledge gained through my former education as an avionics technician with my interest in the ancient ceramic craft, I strive to create kinetic ceramic handicraft suitable for interaction with an audience.By a series of different phases I slowly go from understanding what kind of motion I want my objects to have, to actually realizing this motion in three-dimensional objects. Through the use of simple models made from corrugated fiberboard followed by more advanced plaster models, combined with different complementary materials such as bicycle inner-tubing and recycled aluminium cans among many others, I, through a vast series of testing, slowly build up a knowledge base later applied to the ceramic objects.The result is for me a success; I have found a way for me to combine ceramics with mechanics. Through this I have created kinetic ceramic handicraft intended for interaction with an audience..
Plan för multifunktionella buffertzoner längs Vramsån på Malörten AB: s jordbruksfastigheter
To create multifunctional buffer strips along a watercourse in an economically sustainable way requires consideration of many different factors. In this plan we have selected pollutant reduction as the main purpose of the buffer strip. We have also strived to achieve minimal income loss due to reduced production, increased biological diversity, good game preservation that leads to higher income from hunting, aesthetical satisfaction and possibility to profit from available subsidies. This is done mainly to make landowners/farmers more interested in creating buffer strips along water courses.
As sand is the dominant type of soil in the area, the water course is less affected by surface runoff compared to if the soil would be clay or some other finer texture. Game preservation and subsidies have therefore been the main factors when establishing the width of the strip, because these require wider buffer strips in some cases.
Lodgepole pine - stability after thinning
SCA has today almost 300 000 hectares of their forest land planted with lodgepole pine(Pinus contorta var. latifolia). Due to initial extensive planting in the 1970ies the area oflodgepole pine forests in the thinning age has grown rapidly from the end of the 1990ies.During the years 1996-2005 first commercial thinning of lodgepole pine at SCA took place.The goal of the hereby presented study was to investigate the growth and stability in thosefirstly-thinned lodgepole pine stands a few years after thinning. Furthermore, the objectivewas to investigate the relationship between stand stability and different stand parameters.Additionally, lodgepole pine stem quality was estimated.The study is mainly based on the data collected during an inventory project carried out atSCA in 2008. Altogether 91 lodgepole pine stands in northern Sweden were measured afterthe first thinning.
Naturlig nedbrytning av klorerade lösningsmedel i grundvatten
Chlorinated solvents are common contaminants in soil and water. Under anaerobic conditions microbes are capable of transforming chlorinated solvents into ethylene which would result in a remediation of the contaminated area. In order to use natural attenuation as a remediation method evidence of continuous degradation is required. Furthermore, the degradation must occur at a sufficient rate and continuous monitoring of the site is needed until the demanded levels are achieved. A field study was performed on the basis of data from a dry-cleaning facility contaminated mainly by perchloroethylene.
Fodder to ruminants within agroforestry systems in Rwanda - species and management
Rwanda is one of the poorest countries in the world and about 70-80 % of the population lives in rural areas. The land is strongly affected by land erosion which makes it difficult for the agriculture and food production. Agroforestry is a system where tree plantation is combined with livestock- and crop production. The system provides soil fertilization and binds the soil together. Some of the trees used in agroforestry systems are also used as fodder.
The bioavailability of soluble oxalates in stir-fried silver beet leaves
The prevailing food and energy crisis of the world, due to the declining reserves of fossil energy and a never ending rise of consumption, forces us to look into new fields to supply our energy demand. The boom of bio energy is criticized, as food crops are used to provide biodiesel and ethanol and the volumes are ridiculously small to supply world demand. Algae are one of the world?s oldest life forms and exist in many different phyla, providing a great variety to choose from, for different purposes. Cultivating microalgae offer a way to produce energy at great volumes without competing with food production and at the same time the algae offer a way to use our expensive nutrients in a more efficient way, besides this the algae are carbon dioxide neutral since their carbon source can be supplied by the atmosphere and the additional energy required can be supplied by algal oil or other renewable sources.