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.

The primary purpose of this study has been to investigate the Swedish timber industry?s perception of compression wood. A secondary aim has been to describe particular areas within the production process where compression wood is likely to cause problems. This study has mainly been carried out as a questionnaire. In order to connect the findings to current research, additional information has also been collected by means of a literature review. The questionnaire has been intended for sawmills and wood-manufacturing companies from various production classes and owner categories, as well as from different parts of the country.

Public concern about the release of toxic compounds from wood-based products drives legislation towards enforcing industries to find and use more sustainable solutions for wood treatment. Plant oils are good alternatives to treat wood, minimizing or even neutralizing the impact on the environment. Wood modification with epoxidised linseed oil (ELO) and acetic acid as catalyst has proven a suitable method to impregnate and protect wood. However, the mixture presents a serious inconvenience because of the quick polymerization of the ingredients that limits its practical application. Therefore, this study was designed to evaluate an alternative method using a two-step process which bypassed the problem above.

Environment friendly transports are one of the main topics in the industry and society today.Shell organizes an annual university competition called Shell Eco Marathon. The goal is to buildthe car that consumes the least fuel during a race. KTH participated for the first time in 2006.The engine for this competition, DoubleTwo, has been developed within the school. Theprinciple is a two stroke counter piston HCCI engine with variable compression ratio. HCCIstands for homogenous charge compression ignition.

This thesis explores the possibilities of avoiding the issues generally associated with compression of noisy imagery, through the usage of vector quantization. By utilizing the learning aspects of vector quantization, image processing operations such as noise reduction could be implemented in a straightforward way. Several techniques are presented and evaluated. A direct comparison shows that for noisy imagery, vector quantization, in spite of it's simplicity, has clear advantages over MPEG-4 encoding..

Wood pellets are an upgraded product of residuals from several wood processing industries, for example saw mills and pulp industries. The pellets are produced by pressing the milled and dried sawdust to cylindrical units with a higher density than the initial raw material. Pellets have great benefits compared to the raw material: high energy per volume, good transport and storage properties and homogeneity. Several parameters collaborate in the whole process, which makes it complex. Wood is a heterogeneous material, chemically and structurally dependent on wood parts, habitat and storage procedures.

This final thesis is initiated by the wood fuel department at the Swedish forest company Sveaskog as part of a project which also involves two other final thesises. The overall goal of the project is to investigate Sveaskog´s possibilities to produce and sell different wood fuel assortments in Västerbotten and the southern parts of Norrland. The aim of this thesis is to investigate how much wood fuel Sveaskog can produce in the area during the next five years and what that would cost. Furthermore the thesis will investigate the total possible supply of wood fuel from all other possible producers in the area. Treated assortments are forest residues from final fellings, whole trees from direct wood fuel thinnings, non industrial wood and industrial by-products from sawmills. The main effort to investigate Sveaskog´s production possibilities has been made to calculate the possible annual amount of forest residues and fuel from wood fuel thinnings that can be produced.

This report is a thesis work for a B.Sc. in Forestry exam at the School for Forest Engineers, SLU. The work was an assignment from Sydved Energy AB. The aim of the work was to compare the operational productivity between two kinds of forwarders for extraction of harvesting residues, one forwarder with a special compression device and one ordinary, slightly modified forwarder. Two sites were studied for each forwarder. The study shows that the annual production was about 11,000 m3 higher for the traditional forwarder. The cost for the traditional forwarder was SEK 0.9 lower per m3.

The need of raw material does of course fluctuate but the long term view is an increasing demand due to the growing consumption of sawn timber products, pulp, paper and lately also biomass. This has led to a keener competition for wood. At the same time there is an ongoing structural change of a significant part in the Swedish wood supply market, the private forest owners. In 1992, 22 % of Sweden´s 335 000 private forest owner lived apart from their forest. In 2007 this figure had risen to 36 %.

The purpose of this study is to explain how the value of sawn wood changes when sawn wood are cut in 30 respective 60 cm lengths. The raw material into the saw mill will mainly be bucked in 30cm and 60 cm modules. There will also be two alternatives where the timber will be bucked special lengths, 370, 490 and 550 cm but also in 490 and 550 cm.The method used for the study is to simulate both cutting and sawing the woods. For cutting the simulator Timan is used and for sawing the simulator Timberopt is used. When data is generatedfrom the simulators, calculations of some key figures is done and also how much the revenue need to be increased for the sawn wood in order to cover for the increased costs of changing sawn woodfrom 30 cm to 60 cm modulesThe conclusion is that the single biggest reason, impacting the value of the sawn wood is the cutting at the saw mill.When going from 30 to 60 cm modules, the impact will be that the customers to the saw mill must pay more to increase the revenue by at least 10% for the sawn wood in order to justifice the changein production.It is also possible to increase the value of the products further by bucking the timber in three lengths, 370, 490 and 550 cm, in order to get 12 % increase of the share of longer sawn wood (>= 480 cm)..

A high amount of dead wood is one of the most important prerequisites for high biodiversity on forest land in Sweden. Dead wood is most abundant in young forests, thinned forests, woodland key habitats and protected forest land. In old-growth forests most of the dead wood consists of logs and snags, whilst in managed forests a huge proportion of dead wood is made up of logging residues like stumps and FWD, fine woody debris (< 10 cm diameter). All these different types of dead wood may serve as substrates for epixylic bryophytes and lichens. However, few studies have been conducted on the relative importance of these different fractions of dead wood for the occurrence of bryophytes and lichens, especially when considering dead wood on thinned forest land.

Fire is an important ecological factor, but its consumption of coarse woody debris, CWD, has hardly received any attention. In this study, I investigate the consumption in relation to the time of initial flame exposure and propensity for continued combustion of standing CWD of pine (Pinus sylvestris). Two types of CWD were studied. Firstly, wood that had been dead for one to ten years. Secondly, wood that had been dead for several decades. In the burning experiments, logs of approx.

Since prehistoric time man has used wood to build their environment. The material?s availabilitycombined with its good mechanical properties has often made it the material of choice. Like allmaterials exposed to natures degradative processes the properties of wood decreases over time.Rot, UV radiation and attacks by insects and pests damage wood if not protected. Since we wantwhat we build to consist, optimizing our building materials durability is of great interest.Techniques and methods for increasing the endurance of wood have been developed in severaldifferent places and for a long time.

During the twenty-first century the price of forest land in Sweden has increased heavily. Buying forest land has become more common and the stakeholders have grown in number. The countries around Sweden have through the globalization become connected in the market of round wood and wood products. The price of forest land and round wood are also close connected. The goal with this report is to make a comparison of forest land prices between Sweden, Denmark, Norway, Finland, Estonia and Latvia and to see how the prices have developed in the period 2000-2011. The prime factor in the comparison, except the direct price difference between the countries, is the round wood prices. The round wood prices give information about the economic situation in the countries and play an important role in the return on the forest land. The prices of forest land shifts heavily between the countries.

Today's high oil prices and more stringent environmental requirements have led to that manufacturers of mobile construction equipment try to make their products more energy efficient. With this in mind a project about hybridization of hydraulic systems has been formed. The purpose of this project was to analyze the savings that can be achieved by hybridization of hydraulic systems. A reach stacker truck (Kalmar DRD450-80S4XS) were simulated in some load cases with conventional hydraulic systems and with three types of hybridized hydraulic systems. Different parts of the hydraulic systems were also analyzed separately.