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681 Uppsatser om Soil moisture gradient - Sida 16 av 46

Analys av fuktomlagring i välisolerad parallelltak : Analys med simuleringsprogrammet Wufi 2D

Idag ökar man isoleringen alltmer i takkonstruktion för att spara energi. Ökad mängd isolering minskar temperaturen över takets yttre delar och höjer den relativa fuktigheten där.  Dessutom finns risk att fuktigt material byggs in mellan alltmer täta skikt vilket leder till att det tar längre tid för byggfukten att torka. Detta resulterar i en ogynnsam fuktfördelning med höga relativa fuktigheter över konstruktionen där risken för mikrobiell påväxt ökar. Syftet med denna studie är att utreda hur fuktomlagring sker baserad på inbyggnadsfuktkvoten i välisolerade parallelltak.

DEHP - från mjukgörare till hormonstörande

Eutrophication is a major problem in the Baltic Sea, as a result of increased loading of nitrogen and phosphorus. In the coastal parts of Östergötland the soil largely consists of clay and contains high levels of phosphorus bound to clay particles. Erosion of the soil in agricultural areas makes the water turbid and transports phosphorus to the Baltic Sea. The aim of this project was to examine the relationship between phosphorus and turbidity in the coastal streams of Östergötland. The aim was also to evaluate the possibility to use turbidity as a surrogate measure for phosphorus.

Implementering av konstruktionsändringar inom ett globalt företag : En fallstudie på en indisk produktionsenhet

Långtidsbehandling med ventilator utan tillräcklig befuktning kan torka ut en patients luftvägarmed olika komplikationer som följd. Målet för detta examensarbete var att utveckla en ny teknikför att befukta och värma inandningsgasen. Ett fungerande koncept och en prototyp som styrkerkonceptet skulle tas fram.Marknaden för befuktare studerades och de vanligast använda befuktningsmetoderna granskadesför att hitta svagheter som behövde åtgärdas. De två vanligaste befuktartyperna är HeatedHumidifier och Heat and Moisture Exchanger. Den främsta nackdelen med Heated Humidifiervar dess tendens att övermätta luften med kondensutfällning som följd, och med Heat andMoisture Exhanger att inte tillräckliga fukt- och temperaturnivåer nåddes.Därför togs en ny design fram med målet att kunna styra fukt och temperatur oberoende avvarandra.

Optimering av reducerad bearbetning : högre skörd till lägre kostnad

Optimization of soil tillage and crop rotation is important in many aspects, but particularly in maximizing profit margins. Since the economic outcome is usually decisive, it can be interesting to study different combinations of soil tillage systems and crop rotations in order to identify the maximum economic outcome. How a crop functions in a particular tillage system determines whether it is profitable to grow that crop. Different tillage systems affect the soil and its processes in different ways. Reduced tillage often works best on weak-structured heavy clays and on silty clays.

Monitoring lion movements

Prevention of lion predation towards African livestock is of great importance due to the economical losses farmers have because of this. Predation is also one of the main reasons for human-wildlife conflicts and lions often get killed because of it. Therefore, a pilot study using camera traps was conducted to monitor movements of lions and other wildlife through a wildlife corridor in Ol Pejeta Conservancy. The results were compared with a previous study that counted prints in the soil in front of the corridor. Due to theft risk the cameras had to be taken down and pictures were only collected from nine days.

Frost hardiness of grapevine cultivars as affected by ground cover under Scandinavian conditions

Cultivation of grapevine is novel under Scandinavian conditions. We studied the impact of ground cover on frost hardiness of grapevine cultivars in Northwestern Scania in a two-factorial trial with four cultivars Solaris, Pinot Gris, Siegerrebe, Ortega and three kinds of ground cover (open soil, plastic cover and gravel). The study was conducted in a grapevine orchard, planted in May 2009, in Broddarp on Bjärepenisula Sweden (N latitude 56°; longitude E 12°). Soil and air temperature were monitored continuously. Frost hardiness measurements were performed every second week from late September to early December 2009. Frost resistance, LT50, was determined by electrolyte leakage measurement of the upper stems after artificial freezing at -15 °C.

Turbiditet som ersättningsmått för totalfosforhalt i kustmynnande vattendrag i Östergötland

Eutrophication is a major problem in the Baltic Sea, as a result of increased loading of nitrogen and phosphorus. In the coastal parts of Östergötland the soil largely consists of clay and contains high levels of phosphorus bound to clay particles. Erosion of the soil in agricultural areas makes the water turbid and transports phosphorus to the Baltic Sea. The aim of this project was to examine the relationship between phosphorus and turbidity in the coastal streams of Östergötland. The aim was also to evaluate the possibility to use turbidity as a surrogate measure for phosphorus.

En ?terinventering och analys av den svenska populationen av svart nervmossa (Campylopus atrovirens)

Bristly swan-neck moss (Campylopus atrovirens) is in Sweden a very rare moss that only grows on a few blocks and cliffs around Gothenburg. The species can globally only be found in areas with high precipitation. Rain fall in Gothenburg has increased with a stronger greenhouse effect. Air pollution in Gothenburg has also improved. Mosses generally benefit from these conditions and this papers hypothesis is that the population of the species has grown because of these more beneficial conditions.

Energiförbrukning för putsade, odränerade träregelväggar i fuktigt respektive torrt tillstånd

In recent years, moisture damages have been noticed in rendered, undrained stud walls. The design is built on the principle one-stage tightening which means that there is no air gap in the construction. The damages have occurred when water has permeated through the rendering in leaking connections and fittings for windows, doors, canopies, balconies, terraces and awnings. Behind the plaster carrier, which consists of either polystyrene or rigid mineral wool, plasterboard has often been used as a wind protection barrier. In many cases the wind protection barrier and the underlying wooden studs have been exposed to mould and in some cases even rot.

Investering i spannmålstorkning och lagring på gårdsnivå : en jämförelse av ett silotorksystem med omrörare och en konventionell anläggning

The current situation for Swedish grain farmers facing a situation with decreasing profitability makes it necessary for the farmers to find ways of increasing the margins in their grain growing. Decreasing profitabilities along with Lantmännens closing of grain elevators contribute to the necessity for farmers to invest in grain storing and drying at the farm. By investing in capacity for drying and storage of grain on the farm it is possible to recieve a higher price on the grain sold due to the possibility to sell when the price is higher compared to the harvesting season. An investment in grain drying and storage with a relatively low investment cost that recently has appeared on the Swedish market is the grain stir drying system. This study contains a comparison of an investment in a grain stir drying system where the grain is dried and stored in the same silo and a conventional drying and storage system.

Fältskiktsarter i naturlika planteringar : vilka råd kan ekologer ge?

This paper appeals to professionals working with green questions. It intends to create a discussion about which plant species that can be established in a fieldlayer of a naturelike planting on fertile agricultural land. To initiate the essay, a studie of which values that can be connected with an establishment of a fieldlayer was performed . A part of Tor Nitzelius Park in Alnarp, a so called naturlike planting on fertile agricultural land, was used as a model for the choice of species. With the aid of soil values, photos and a list of current species, interviews with four ecologists were performed.

Är kolrika jordar en källa till fosforläckage? : en sammanställning av data från 130 åkerjordar

Phosphorus (P) is an essential nutrient but a surplus could lead to eutrophication. Furthermore, the minerals used to produce the mineral phosphate is a non renewable resource. There are in other words several reasons to reduce the leakage of P and the agriculture is one important area to attend. The aim of this work has been to investigate if carbon-rich arable soils content contain more P than arable soils with low carbon content. Moreover it has been calculated if the carbon-rich soils could pose a risk of P leakage by comparing their delivery of P with the plant uptake. The work has consisted of compiling the results from former gathered and analysed soil samples of 130 Swedish arable soils. The fractions of P considered are water soluble P (Pw), ammonium lactate-extractable P (P-AL), hydrochloric acid-soluble P (P-HCl), organic ammonium lactate-extractable P (Porg-AL) and inorganic ammonium lactate-extractable P (Porg-HCl).

Studie av koldioxidgradienter i havets ytskikt

Studie av koldioxidgradienter i havets ytskiktSofia SöderholmDenna studie bygger på ett nyligen utvecklat instrument som har mätt koldioxidkoncentrationer på tre olika djup i vattnet samt en nivå i luften. Då detta instrument var oprövat i vatten har en utvärdering av mätmetodens lämplighet för vattenmätningar utförts. Syftet med mätningarna var att undersöka ytvattnets vertikala koldioxidgradient för att med hjälp av denna kunna beskriva flödet av koldioxid mellan hav och atmosfär bättre. Detta flöde är en viktig del av den globala kolcykeln och en djupare förståelse för koldioxidflödets beteende kan i framtiden bidra till mer noggranna klimatprognoser. Hur de beräknade flödena från profilinstrumentet påverkas av temperaturgradienterna i vattnets ytskikt har även det studerats.

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.

Energieffektivisering genom förvärmning av flis till kokare med sekundärvärme

The Swedish pulp and paper industry meets higher demand for energy efficiencyi mprovements with increasing energy prices and changes in the Swedish renewable energy certificate system. One action of energy efficiency improvement is by using secondary heat, that otherwise would have been treated as waste heat, for use in a system with lower temperature demands. The aim of this Master´s thesis is to identify possible secondary heat sources in a typical Swedish pulp and paper mill and to investigate what economic benefits the secondary heat will provide when being used for pre heating of wood chips to a kraft digester.The Master´s thesis focuses on three secondary heat sources; dry warm air, warm water and moisture saturated warm air located inside the pulp or paper mill. Two types of kraft digesters are simulated within this study, a typical Scandinavian digester and a modern twin vessel steam phase digester.Due to quality aspects and low temperature level drying is the drying technology with dry warm air rejected. Using warm water in direct contact with wood chips increases the quantity of water to the evaporation plant and thus reduced pulp or paper production and is therefore also rejected.

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