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2171 Uppsatser om Springback and density of the compressed wood. In addition - Sida 19 av 145
Uttag av energisortiment vid gallring av contorta, ett komplement till konventionell gallring? :
A recommendation for stand treatment of lodgepole pine (Pinus contorta) is, in a scientific point of view, lacking when it comes to harvesting for biomass energy. Within the next decades it is expected that 280 000 hectares of lodgepole pine will have reached thinning age on the domains of Svenska Cellulosa Aktiebolaget (SCA). Due to this the interest has grown rapidly for studying the possibilities of harvesting biofuel assortments already in the first thinning.
In this study the distribution of the biomass within lodgepole pine trees has been studied and taken into account for estimating the proportions of harvested assortments when using different methods of thinning. The methods studied were conventional biofuel-harvesting (with delimbed branches gathered separately from the round wood) and thinning with cutting of round wood and long tops (incl.
Kan biologisk mångfald ökas i ett avsatt skogsområde? : skötselplan för Storskogsberget på Holmen skogs marker, distrikt Umeå
The biodiversity of the Swedish forest has degenerated since the beginning of the 19th century when fire suppression and large scale logging first occurred. Together with a changed land use, these actions today have had a negative influence on many forest dwelling species, due to gradual reduction of natural processes, successions and different structures from the forest ecosystem. The Swedish Forest Act, together with different environment certifications, have today encouraged private persons and forest companies, among them Holmen Skog, to work actively to improve nature conservation. The aim of this study was to, by field inventories of already existing nature values, literature studies, recommendations from scientific reports and ecological gap analysis as a basis, make a management plan, for a non-production area, to conserve or improve the prerequisites for biodiversity. ?Storskogsberget? is located in the coastal area of Västerbotten County, 35 km from the city of Umeå.
Torrefaction of biomass : a comparative and kinetic study of thermal decomposition for Norway spruce stump, poplar and fuel tree chips
Stump biomass is energy rich and stump harvesting for use as fuel become more and more
interesting in Sweden. Swedish Forest Agency (2009) has estimated that stump harvesting in
Sweden would respond to an annual energy supply of 57 TWh/year. However, stump has not
been recognized as a bioenergy resource in Sweden. Suitable methods for pre-treatment of
stump are probably of great importance to make it accepted as fuel. It is therefore rewarding
to carry out an investigation in this area for stump.
This report represents results from a diploma project, which was aimed to develop a fixed bed
reactor for experimental study of biomass torrefaction, followed by TG analysis and kinetic
modelling employing Ozawa method and different kinetic models including one-step and
three-pseudo-component models.
Naturhänsynen i FSC-standarden : vetenskap eller gissningar?
The Swedish FSC standard (Forest Stewardship Council) is a level standard used to certify forestry. All the major Swedish forest companies are using the FSC standard, and approximately 50% of the Swedish forests are FSC certified today. In the essay six items within the chapter on environmental issues and biodiversity are examined: the proportion of protected forest, the proportion of annually burnt clear-cut stands, the number of trees with large diameter, the amount of dead wood, the proportion of deciduous trees within a stand and the proportion of deciduous-dominated stands. The FSC standard states a level for all items, and the purpose of the essay is to analyse whether these levels are supported by research within the field of conservation biology. The validity of the levels of the six items is them discussed to evaluate whether changes are required to the next revision of the FSC standard.
Safe retrieval of nutrients to improve food security
Safe retrieval of nutrients from human excreta to fertilize crops in order to gain adequate yields will increase food security and sustainability in agriculture areas with nutrient-poor fields. Safe and nutritious food will meet the dietary needs of the individual which promotes public health and the ability of an active life. Human excreta should be considered as a resource instead of being assumed as waste. Human faeces and urine is excellent fertilizers which may close the nutrient loop if utilized properly. However, sanitation of the excreta is required to prevent disease transmission by reducing the content of gastrointestinal pathogens such as bacteria, viruses and parasites.
The objective of this study was to in small scale evaluate the sanitation in a combined liquid compost and urea treatment by monitor the inactivation of bacteria and viruses at the combination three start temperatures, 45, 40 and 35 °C, and three additions of urea, 0.5, 0.75 and 1 % and reference, 0 % urea addition.
Sortimentsinriktad avverkning
Forest enterprises have always searched for ways to improve efficiency. For the past few
years there has been an emphasis on stock-keeping levels. Increased demand for fresh
round timber and the need to decrease the amount of tied-up capital has made the forest
industry reduce its inventory levels. This has brought on a higher demand on the timber
supply from the forest management districts concerning both delivery in time and
assortment output. As a result, the flow of timber has fluctuated a lot with serious
consequence for the timber supply during 1994.
Positionssystemet - Möjligheter och begränsningar
Vi använder oss av ett positionssystem när vi skriver tal vilket ofta är en oreflekterad kunskap, denna kunskap förväntas elever tillägna sig redan i årskurs 1-3. Vi har under vår verksamhetsförlagda utbildning sett att vissa elever har svårt att förstå detta system. Därför är syftet med denna litteraturöversikt att undersöka vad befintlig forskning säger om elevers möjligheter och begränsningar i lärandet av positionssystemet. Materialet samlades in genom systematisk litteratursökning i flera databaser. Litteraturen som sedan analyserades och kategoriserades bestod av tretton stycken forskningsartiklar, en avhandling och en proceeding.
Förändrad aptering av massaved från 3- till 4-meterslängder vid gallring inom Södra : en systemanalys av effekter från avverkning till levererad virkesråvara
The costs of logging and of transportation with truck are dominating the total cost of wood delivered at industry. To support the profitability for the members' forestry the processing and handling with the timber has to be as efficient as possible. Increased length of pulpwood in thinning is one conduct that can result in higher productivity and/or lower costs. The study is scaled as a system analysis with the aim to exemplify the differences between working with 3- and 4-meter as standard length of pulpwood, related to biological aspects, timber receipts, cost of logging and cost of transportation with truck. Important aspects are if the change is technically and biologically feasible and economically profitable.
Store Image Perceptions in International Retailing: an Empirical Comparison of IKEA?s
It has been found that customers in the home market perceive the retailer?s store image more positively than customers in the host market, even though this study has found that theretailer?s store image is generally perceived very positively by customers in both examined markets. In addition, this thesis has found that there is a significant difference in how IKEA?smanagement and customers perceive its store image. It can also be concluded that IKEA management perceived store image more positively than customers.
Den bäcknära zonen vid små skogliga vattendrag i Värmland : generell beskrivning, förekomst av traktorspår samt kvicksilverhalter i körpåverkat ytvatten
Forest streams and the associated riparian zones are sensitive to disturbances and changes that occur within these riparian areas. Particularly sensitive are small streams of low order, which will have large impacts down-stream. The disturbances that occur in the riparian zones are reflected quickly in the stream. Driving with forestry machines in the riparian zone will have detrimental effects to the soil and water. Driving the machines will lead to changes in the mineral soil composition, resulting in the reduction of porosity, less infiltration, compaction, and an increased bulk density.
Alternativa finansieringsmöjligheter av företagsfastigheter
It is essential to reuse- and recycles residues to decrease the amount of deposit materials and reach sustainable energy use. Two ways to work towards this is to recycle wood ashes to the forest as nutrient compensation and extract biogas from combustion of biomass.The aim with this study was to decide whether wood ashes that been used for biogas upgrading with accelerated carbonation also can be used as a nutrient compensation in the woods according to recommendations from the Swedish Forest Agency (Skogsstyrelsen).The ashes that were used in this study came from Johan Andersson who works at JTI in Uppsala, who also treated the ashes with biogas. The ashes have, in both untreated and treated condition, been analyzed in this study according to contents of elements, leaching properties, hardening properties and contents of crystalline phases, to evaluate what impact carbonation with biogas has on the ashes.The accelerated carbonation led to hardening of the ash, and decreased amount of CaO- and increased amount of CaCO3. The CO2-uptake also entails a dilution of the elements, and the content of nutrients and trace elements decreases. However the results show an indication of an uptake of S from the biogas to the ash, since the dilution had a smaller impact on S than the rest of the elements.
?R KUSTN?RA ALK?RR I BOHUSL?N ETT ?BLUE CARBON? HABITAT?
In coastal wetlands carbon/organic matter can be stored for long periods of time thanks to, among other things, the presence of water which slows down the decomposition. Because of this, restauration and management of such habitats have the potential to decrease the emission of greenhouse gasses and help mitigate climate. Internationally these environments are called ?blue carbon? ecosystems. In Sweden, alder (Alnus glutinosa and Alnus incanata) covered wetlands along the coast is a nature type that potentially could function as a ?blue carbon? habitat.
Variationer av klor, svavel och aska i havrekärna : odlingsfaktorernas inverkan på havrens bränsleegenskaper
The increasing oil prices during the last years have made it profitable to use cereal grains as a fuel. When compared with wood, cereals contain higher amounts of Cl, S and ash. The Cl and S content makes the gases from cereal combustion more corrosive than gases from wood combustion. The goal of this master thesis was to find out the variation of Cl, S and ash content for oat grain grown under different conditions. Oats was chosen because in Sweden it's considered as the cereal with the best fuel qualities.
Energianalys av etanolproduktion : en fallstudie av Lantmännen Agroetanols produktionssystem i Norrköping
In this thesis an energy analysis of ethanol production at the ethanol plant of
Lantmännen Agroetanol in Norrköping has been performed. The ethanol plant has
been studied in combination with Händelöverket, the combined heat and power
plant which provides the ethanol process with steam. The purpose of this study
was to determine the energy consumption for the whole production chain from
grain to ethanol. The analysis has included the energy consumption for cultivation
of grain, production of chemicals, the production chain for wood chips, the steam
production and the ethanol plant. The grain and wood chips are both considered
raw materials there for the energy content in these are not included as energy input
in the system.
Energianalys av etanolproduktion : en fallstudie av Lantmännen Agroetanols produktionssystem i Norrköping
In this thesis an energy analysis of ethanol production at the ethanol plant of
Lantmännen Agroetanol in Norrköping has been performed. The ethanol plant has
been studied in combination with Händelöverket, the combined heat and power
plant which provides the ethanol process with steam. The purpose of this study
was to determine the energy consumption for the whole production chain from
grain to ethanol. The analysis has included the energy consumption for cultivation
of grain, production of chemicals, the production chain for wood chips, the steam
production and the ethanol plant. The grain and wood chips are both considered
raw materials there for the energy content in these are not included as energy input
in the system.