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987 Uppsatser om Soil concrete - Sida 13 av 66

Kortsiktig fosforeffekt av avloppsslam : krukförsök i växthus där järn-, aluminium- respektive kalkfällt slam använts som fosforgödselmedel

The short term effect of phosphorus in sewage sludge was investigated to establish howmuch of this a farmer can grant him- or herself, if using sewage sludge as a phosphorusfertilizer. Possible differences in plant availability between sludge phosphorus precipitatedby iron, aluminum or calcium integrations were studied in a sandy soil at two pH levels.The sludges were analyzed using pot and incubation trials. As the intention was to investigategrowth limitation due to phosphorus deficiency, a soil with low phosphorus supplywas chosen as well as a low phosphorus application rate. Sludge corresponding to 12kg phosphorus per hectare was applied. Treatments fertilized by sludge were compared totreatments where 0, 6 and 12 kg phosphorus per hectare from mineral fertilizer was applied.Every treatment was replicated six times.

Varierad kaliumgödsling i potatis : en fältstudie i Hedemora

Variation in tuber quality within a single field was one of the motives for a pilot study in Halland, in south-western Sweden conducted during 2002. Quality problems in potatoes have been increasing due to the aggregation of several small fields with different land use history into larger farm units, which are heterogeneous in soil properties and fertility. The study in Halland indicated that both the uniformity and the mean size of tubers may increase from site-specific K fertilization, whereas total yields may be unaffected. The results from this pilot-study with site-specific fertilization showed that tubers reached a more uniform quality and gave a more uniform mean size, while the total yield wasn't affected at all. Site-specific K-fertilization has been applied for some years in Halland with good results. The aim of this study was to test this technique in another potato growing area.

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.

Införande av mjuka golv för mjölkkor : en fallstudie

Soft rubber flooring have gained in popularity over the last years. Rubber flooring al-lows cow to move more freely without slipping and improves claw and leg health. The purpose of this study was to investigate the influence of a stepwise introduktion of soft flooring on cow`s placement in cow houses with robotic milking. A case study was carried out in a herd in northern Sweden with 41 cows. Observations were made every 15 minutes between 09.00 and 16.00 concering cow placement in cu-bicles, in cubicle alley, in feeding alley and in feeding alley with the head through feed-ing gate. One observation period was carried out per flooring alternativ: 1) all concrete slatted floor, 2) rubber slatted floor in feeding alley and concrete slatted floor in cubicle alley and 3) rubber slatted floors in feeding alley and solid rubber floors in cubicle alley. The study showed that 6 %-units fewer cows lay in the cubicles when the feeding alley surface was slatted rubber.

Fuktproblematik i platta på mark : En analys av uppkomsten till fuktproblem

When constructing a building, a number of aspects must be harmonized in order for it to fulfill requirements ? a building must fulfill requirements such a load-bearing, conservation of energy and a good indoor environment by means of, among other things, moisture proofing .Moisture problems in buildings can affect health negatively. As we are increasingly staying in indoors, demands on a good indoor environment are higher.This work starts with examining moisture problems in slab-on-ground solutions, and then links the various scenarios to moisture problems in a concrete slab of a real building. The building with moisture problems is located in Årby by in Borlänge and moisture damage was found in the slab at an apartment adjoining wall.By reviewing literature written within the field of moisture problem, making hand calculations and modeling in the program Comsol Multiphysics, judgments are made to find explanations as to why the rise of moisture occurred in the building in Årby by.Generally, the following guidelines may be used to reduce the risk of moisture problems in slab-on-ground constructions:Drying of construction moisture before laying the floor material.Using draining layer beneath the slab, to prevent capillary suction.Using insulation under the slab, partly for comfort and to establish the temperature difference between the ground and the concrete slab.Avoid direct contact between the wood and concrete, due to degradation and fouling smells that normally occurs.If necessary, use additional vapor barrier.In addition to the above, there are various methods for moisture-proof and moisture-monitoring by design or by the method ByggaF suited for the entire construction process various events..

Effekt av olika kvävegödselmedel på utvecklingen av klumprotsjuka i salladskål (Brassica rapa ssp. pekinensis)

The price trend on rapeseed the latest years has led to an increasing interest to grow the crop among many farmers in Sweden. The price trend has resulted in more than a doubling of the oilseed area since the early 2000s. For many farmers it is an advantage to increase cultivation of rapeseed because of the high proportion of cereals in the crop rotation on many farms, but it is not just benefits. The risk of the fields being infected by clubroot increases within frequent rapeseed cultivation and it often leads to subtantial economic losses. Clubroot is caused by Plasmodiophora brassicae that is a soilborne pathogen in genus Protozoa and its resting spores can be found in the soil for up to 18 years.

Erfarenheter av utedrift med köttdjur i Sverige och Kanada :

Beef cattle wintering outdoors should be provided a shelter, e.g. a type of barn or corresponding. This type of production requires appropriate soil types and secured animal welfare. For example, a clean and dry resting place needs to be provided to the animals. To receive an exemption for buildings the farmer has to have something equivalent that provides an adequate shelter.

Inhysningssystem för växande ungtjurar

The purpose of this study was, if possible, to find a housing system for growing bulls that was as optimal as possible for the animal welfare. In order to select housing systems you must take into account the size of the group, body weight and the type of floor. Seven of the international most common housing systems were compared, straw bedding, deep straw bedding, sliding straw bedding, concrete slatted floor, rubber coated slatted floor, cubicles and feeding cubicles. Studies that have examined the proportion of tail, claw and leg injuries and the presence of unnatural behavior in the different systems. In summary, all studies showed that soft underlay were beneficial for the animals in terms of the proportion of bone lesions and swellings.

Effekten på nedbrytningen av rötter vid tillförsel av ammonium sulfat i en granskog i sydvästra Sverige

Decomposition of organic matter is a critical process in the ecosystem, which involves many essential biotic and physical parts. Decomposition is therefore an important process both above and below ground. The rate of decomposition is dependent of many environmental factors for example: pH, moisture and supply of oxygen. The decomposition can therefore be affected by large scaled environmental influences, such as acidification and climatic changes. The root litter in the forest is in different ways affected by acidification, liming and manuering.

Användning av högpresterande betong i husbyggnader : Materialförsök och modellering

Idag är intresset för högpresterande betong (HPB) växande runt om världen då fördelarna är många, eftersom slankare, tätare, starkare och lättare konstruktioner kan tillverkas. Detta examensarbete handlar om materialförsök och modellering för en typ av HPB som ska användas i husbyggnation. Arbetet inleddes med materialförsök i färskt tillstånd, där god gjutbarhet och konsistens eftersträvades. Utgångspunkten var från ett grundrecept med två olika ballastsorter (slaggballast med flygaska och krossballast från asfaltindustrin med silikastoft), vilka namngavs till pilotförsök 1 och pilotförsök 2. Vidare valdes pilotförsök 1 att provas i hårdnat tillstånd då det visades att det var mer ekonomiskt lönsam eftersom ballasten inte behövde siktas, lägre vct tillhandhölls och att flygaskan som användes i pilotförsök 1 är billigare än silikastoft som användes i pilotförsök 2. Resultaten efter 28 dygn för de materialförsök som utfördes i hårdnat tillstånd var:Tryckhållfasthet; 141,9 MPaDraghållfasthet; 7,0 MPaBöjdraghållfasthet; 10,0 MPaElasticitetsmodul; 46,4 GPaKrympning efter 56 dygn; 0,5 ?Samtliga försök utfördes enligt svenska standarder (SS). Dessutom vidareutvecklas och förbättrades ett redan arkitektoniskt gestaltat Attefallshus ur ett konstruktions- och hållbarhets perspektiv, där fokus låg på transport- och produktionsförutsättningar.

Eurokoder : en jämförelse mot BKR

In Sweden there are currently two separate guidelines you may use whenperforming calculations on frameworks, BKR and the Eurocodes. Although at theend of 2010 you are not allowed to use BKR any longer and only the Eurocodeswill be viable. The aim of this thesis is to explain how the Eurocodes and EKS work and alsohow they compare to the current guideline BKR. Similarities and differencesbetween these guidelines are also discussed so that the reader will get a betterunderstanding of how the Eurocodes are applied. The areas discussed are asfollows:Principles and adviceSafety ClassesSymbols and IndexesLifespanLoads and partial coefficientThe thesis also deals with the impact that this transition into a new guideline willhave on corporations, guideline costs, education and computer software. As anexample a rough estimate on what costs this transition will create on a companywith 20 employees is also included. Calculations have been performed in order to investigate how the design valuesdiffer between the two guidelines, the Eurocodes and BKR.

Askans inverkan på beläggningstendensen i ett biobränsleeldat kraftvärmeverk och växtplatsens påverkan på askegenskaperna :

This report was written by Sofia Ericson and describes the degree thesis with the title: ?Connections between the growing site of bio fuel, the chemical composition of bio fuel ash and the deposit growth in a bio fuel fired boiler.? The purpose of this degree thesis was to avoid melted deposit growth in the bio fuel fired boiler at ENA Kraft in Enköping. Potassium and sodium are known to lower the melting point of bio fuel ashes and are therefore not wanted in the trees in higher amounts than necessary for the growth. Silicon is also known to be important for the deposit growth but it is not possible to say in general if higher or lower contents of silicon is better. The relation between silicon and other chemical substances is more important than the total amount of silicon.

Laborativ matematik : - Fem pedagogers syn på laborativ matematik

The students are usually eager to develop their mathematical learning. However, the Skolverket can see that this eagerness passes in the early years of school. A study shows that a varied mathematical education creates enthusiasm to learn, which can decrease the negative view of mathematics.The purpose of this study is to see how five pedagogues use laboratory mathematics, their approaches to laboratory mathematics as well as to find out their role in the laboratory education. The result of the study is based on interviews with the pedagogues, who are all teachers for students in year F-3. All of the pedagogues work in a laboratory way, but to different extents.The study shows that the pedagogues aim to make the mathematics as concrete and everyday as possible.

Reflekterande eller reproducerande matematik : en jämförande studie mellan två undervisningsmetoder i matematik, det laborativa och det traditionella

In each classroom there is a teacher with good intentions wanting what´s best for their pupils. But grades and tests in mathematics from 2009 in Sweden shows there is a crack between the subject being taught and the learning child. The purpose with this research is to find an understanding from a teaching and learning perspective of which teaching method is more suitable for teaching and learning mathematics by doing a comparison between two methods. The main question is:What are the advantages and disadvantages of the traditional and the laboratory method of teaching, supported by the two keywords teaching method and learning?This C-paper is based on a qualitative research aiming to gather an in-depth understanding of human behavior.

Försök med olika såmaskiner vid konventionell sådd och direktsådd

In this thesis, two studies with different drills were included. In one of the studies two drills were compared: Väderstad Rapid and Väderstad Spirit. In the other study various drills for direct drilling were compared. The study with Rapid and Spirit was placed in two locations with different autumn tillage; one on ploughed land in Uppsala and one on cultivated land in Västerås, both with relatively high clay content. Rapid drills have a single disc coulter, while the Spirit drills have a double disc coulter. Various aspects were compared such as aggregate distribution, seed placement, emergence, crop yield and economic outcome.

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