Sökresultat:
176 Uppsatser om Moisture - Sida 5 av 12
Hårdgörning av Asp
Hårdgörning av trä syftar till att göra materialet hårdare. Detta går att åstadkomma genom komprimering, det komprimerade materialet tenderar dock att återgå mot sin ursprungsform då materialet utsätts för fukt om ingen låsning sker. Låsningen kan ske mekaniskt i en treskiktskonstruktion som motverkar träets fuktrörelser. Dessa skivor har dock visat sig vara instabila och tidigare försök har uppvisat deformationer i form av kupning. Denna undersökning syftar till att utreda förutsättningarna för att använda komprimerad asp samt att ta fram underlag för framtagning av en kommersiell produkt.Praktiska tester har genomförts för att studera hårdhet, återfjädring och densitet hos det komprimerade virket.
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.
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.
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.
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.
Strötorvsanvändning i djurstallar : en litteraturgenomgång
Peat litter has been used in animal houses for a long time. Because of its good ability to absorb liquid and nutrients from the manure it can create a dry surface for animals and a valuable manure product. Through changes in agricultural practises the use of peat litter has diminished and is to a great extent replaced by straw, sawdust and cutter shavings although Sweden is rich in peat-findings.
The aim of this work was to summarize the presented knowledge about the used of peat
litter, techniques, advantages and disadvantages and to compare with other commonly
used litter materials. Articles on peat litter have been searched for in magazines, databases and books at SLU library. Visits to peat industries, interviews with peat producers and with peat researchers contributed to the material.
Peat is not a uniformly material.
Fuktrelaterade risker vid lågenergikonstruktion i lättbetong : En studie av ett nyproducerat passivhus
Trenden i byggbranschen är att efterfrågan på täta, energisnåla byggnader ökar. Passivhus och andra lågenergikonstruktioner blir vanligare och vanligare. Riskerna med att bygga in organiskt material som trä i dessa konstruktioner har fått branschen att börja titta på alternativa material. Lättbetong är ett material som både har bärande och isolerande egenskaper. Dessutom är det inte organiskt vilket gör det okänsligt för mikrobiell påväxt.
XRF-analys av förorenad mark : undersökning av felkällor och lämplig provbearbetning
X-ray fluorescence (XRF) detection of heavy metals is a cost- and time-effective method for investigation of polluted areas. Compared to laboratory analysis, XRF analysis is limited by high detection limits and uncertainties in some situations. Preparation of samples is known to affect the results of measurements.The purpose of this thesis is to bring a deeper understanding of how different factors affect the results of XRF-analysis. A large number of measurements have been made with the instruments Niton XLt 700 and Niton Xli 700. Results from measurements of lead, zinc and copper have been analysed.This study has shown that a greater Moisture content will give a lower measured concentration for the same sample.
Jordbearbetningsstrategier på hösten inför vårsådd på tyngre lerjordar :
It is important for today?s farmers to minimize the costs for crop establishment, because
of decreased prices and support from the EU. Farmers, who plow in autumn on heavy
clay soil, often do some kind of tillage in autumn to get better soil structure before
spring seeding. This is especially important when growing small seed crop, e.g. sugar
beet and oil plants.
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.
Majstorkning :
The corn plant came to Europe with Christopher Columbus in the 14th century and have
ever since bin cropped here, but corn haven?t bin very common in Scandinavia until
recently. The mainly use for this crop silage but even corn for grain is cropped in
Europe. Corn for grain is a common part of feed in beef and chicken farming. In Sweden
corn for grain is pretty rare but almost 1000 hectares are used for this crop, Lantmännen
Sverige is the biggest buyer of corn at the moment.
Vad styr förekomsten av sälg och asp? : en studie av olika beståndstyper inom Hamra kronopark, Dalarna
Aspen (Populus tremula L.) and goat willow (Salix caprea L.) are two important tree species in the aspect of nature conservation. Due to the elimination of forest fires, a former negative attitude towards deciduous trees in forestry and a strong herbivore pressure, these tree species have been negatively affected during the last fifty years. The aim of this study was to investigate whether the occurrence of aspen and goat willow could be related to either human impact or to site properties, such as ground Moisture and vegetation type. A side study included an inventory of a number of cyanobacterial tree lichens on aspen and goat willow in order to try to relate the occurrence of these lichens species to stand history and stand properties.
The study was performed in Hamra State Forest in northern Dalarna. Nature reserves were compared with stands in managed areas.
Fältmätningar av limträbalkars elasticitetsmoduler : utvärdering av tre mätmetoder
This study investigates three different methods for evaluating MOE,Modulus of Elasticity, in field measurements. The purpose is toinvestigate the possibility to use dynamic measurement methods infield measurements that hitherto (2010) has been performed with staticmethods. The objects of investigation are 20 glulam beams. The firstfield measurement took place in november 2007 and applied a staticmethod based on the standard SS-EN 408. The second measurement,described in this study, took place during summer 2010, and appliedstatic as well as dynamic methods.The MOE of wood is affected by a range different factors.