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2143 Uppsatser om Clear-cutting - Sida 3 av 143
Återväxt av blåbär (Vaccinium myrtillus L.) efter ångbehandling : orsaker till effektiv kontroll
Steam was used as a site preparation method to eliminate unwanted bilberry (Vaccinium myrtillus L.) in the boreal forest. The efficiency of steam to suppress bilberry was compared with prescribed burning and cutting the bilberry. Different combinations of steaming and/or cutting the bilberry were set up to investigate in which way steaming and cutting influenced the sprouting and regrowth of bilberry. The regrowth of the bilberry vegetation was monitored for 40 month. Steam was most efficient in suppressing bilberry.
Potential för energiklippdrivare i Skåne : markägarintresse, råvarutillgång & ekonomi
As the Swedish governments long term goals include a reduction of fossil fuel dependency,
increasing pressure is placed upon energy companies to create and develop new solutions for renewable energy. The following case study was done in collaboration with the company
Sydved Energileveranser AB and one of their contractors, Enarssons Skogsentreprenad AB.
The objective of the study is to examine the bioenergy situation in region of Skåne and
evaluate the potential solutions in the region for a forest-fuel assortment, based on a bioenergy-cutting-system. As a part of this study I have compared ordinary manual cuttings done with a chain saw and cuttings made using the new ?bio- energy cutting system?. The cuttings made under both systems were tested in areas near agricultural fields or pasture land in order to maintain an open landscape.
GNSS-Styrning : Information för platschefer
An investigation of the heat impact of laser cutting on the material properties when producing tensile and impact test specimens of different steel types of varying thickness has been performed. The purpose of the thesis project was to provide recommendations regarding how much material that needs to be milled from the laser cut edge before tensile and impact tests. The study has been performed partly by investigating the test specimens by heat camera when the specimens were cut in the laser cutting line and partly by performing hardness tests, investigation by microscopy, and tolerance and roughness measurements and tensile tests of the laser cut material and material produced in the traditional multi operation machine. The results show that the heat affected zone in the thicker materials is greater than previously thought of, and that the currently used recommendation has to be adjusted. The study clearly shows that the thicker the material, the greater the heat affected zone, independently of the steel type, since the thicker material takes longer time to cut.
Frigörelse av kvicksilver och metylkvicksilver till bäckvatten under olika perioder efter skogsavverkning :
High levels of Hg in fish in Swedish lakes have been a problem along time in Sweden. The major concern is production and accumulation of the most toxic form of mercury; methyl mercury (MeHg). Consequently, in about half of our 83 000 lakes fish contain concentrations above the recommended limit for human consumption of 0,5 mg mercury per kg fresh weight (most of it in the form of MeHg). Consumption of fish containing too high levels of MeHg may cause problems for both humans and animals.
Three major sources of MeHg in surface waters are: 1) runoff from terrestrial areas, 2) deposition from the atmosphere, and 3) internal production of MeHg in lakes and streams. The aim of this study was to investigate the effect of Clear-cutting on the concentration of Hg and MeHg into draining streams.
FE safety analysis of a high speed wood planer cutter. An alternative method to achieve the requirements of EN847 standard
In the last decades, high speed cutting has become an attractive technology in the wood industry. The possibility of reducing global costs in addiction with an increase in productivity, were the main reasons for the enlargement of the use of this technology. As usual, these advantages are accompanied by disadvantages that should be carefully analyzed. If on the one hand cutting forces are reduced with increasing cutting speeds, on the other hand, the centrifugal forces affecting the tool are higher. Exposed to such high loads, there is a considerable risk of tool failure that embeds hazards for both machine and workers.
Utredning av laserskärningens materialpåverkan inför drag- och slagprovning : Teknisk Fysik med Materialvetenskap
An investigation of the heat impact of laser cutting on the material properties when producing tensile and impact test specimens of different steel types of varying thickness has been performed. The purpose of the thesis project was to provide recommendations regarding how much material that needs to be milled from the laser cut edge before tensile and impact tests. The study has been performed partly by investigating the test specimens by heat camera when the specimens were cut in the laser cutting line and partly by performing hardness tests, investigation by microscopy, and tolerance and roughness measurements and tensile tests of the laser cut material and material produced in the traditional multi operation machine. The results show that the heat affected zone in the thicker materials is greater than previously thought of, and that the currently used recommendation has to be adjusted. The study clearly shows that the thicker the material, the greater the heat affected zone, independently of the steel type, since the thicker material takes longer time to cut.
Empirisk studie av den radiella förspänningskraftens variation i klassiska skärskruvförband
In this study, the pre-tension force in an insert screw connection are examined in order to establish a greater understanding of the system and to facilitate the process of making new metal cutting tools. Certain especially significant design variables such as the offset, the length of the contact thread and the shank length above the threaded hole, are selected to be closely examined. A comparison of the influence on the pre-tension force between threaded holes made with a worn, versus new, threading tool is also involved in the experiment. The study is limited to handling the screw sizes M2,5 and M3,5. The results show that a regression model, with good approximation, can be fitted to the measured values.
Restspänningar i arc-förångade (Ti(1-x)Al(x))N ytskikt
This report is the written documentation of a project work carried out at the Division of Engineering Materials at Luleå University of Technology in cooperation with Seco Tools AB. The project deals with the analysis of residual stresses in Ti-Al-N thin film grown on WC/Co cutting inserts. The composition of Al varied from 0% up to 75%. Increasing the Al content in the Ti(1-x)Alx N compound improves the compressive residual stresses even after annealing of the material. The experiments have been performed in a high temperature x-ray diffractometer (HTXRD) where the interplanar atomic spacing was determined in-situ and subsequent converted into stresses.
Framtidens meny för ett IT-system
The mission was to create a prototype of a menu system for the companySystem Andersson AB. The instructions were that it has to be as interesting andmodern now as in 20 years. We had to look at technology from the cutting edgeof development to make our prototype survive in the future. WindowsPresentation Foundation (WPF) was the technique we focused on. There areonly a few applications that take advantage of WPF today, but it is predictedthat WPF will be the next generation method for developing applications to theWindows platform.To make our menu visually appealing, easy to use and at the same timefunctional, we followed the clear path and guidelines that are available ininteraction design.
Anlockning och gnag av snytbaggar (Hylobius sp.) : effekt av plantstorlek och behandling med metyljasmonat
Two field experiments were conducted in central Sweden in order to: 1) Determine a relationship between the number of approaching pine weevils (Hylobius sp.) and the number of attacks by pine weevils, in relation to the size of seedlings of Scots pine (Pinus sylvestris). 2) Determine if application of methyljasmonate (MJ) on seedlings of Scots pine will result in higher resistance towards attacks by pine weevils and/or have any effect on the number of approaching pine weevils. The field experiments were designed with two separate parts in close vicinity on the same clear cuttings: a) pitfall traps placed in patches of scarified soil that caught approaching pine weevils at 2.5 cm from the bait, which consisted of different sized seedlings of Scots pine some of which were subjected to application of MJ and b) the same type of seedlings planted out in patches of scarified soil.
The first field experiment was conducted on a 1-year old clear cutting outside Uppsala in east central Sweden and the trapping part of the experiment consisted of 8 blocks with 6 treatments: 1) control, 2) small over-wintered seedling, 3) medium sized seedling, 4) medium sized seedling treated with 0.5 ml 100 mmol MJ 4 days prior to start of experiment, 5) large seedling, 6) vial with 9.5 ml of ?-pinene. The trapping experiment lasted for 6 weeks in the early summer.
Förslag till ombyggnation av klipp- och bockningsmaskin
This thesis work has been performed on request by SWT (Scandinavia WeldTech AB). SWT manufactures, develop and sell ready to assemble building systems for concrete rafter beam applications. The beams in this system consist of a u-beam that is welded to a flange. To be able to fill the beams with concrete there is holes in the beams top end. The holes are made in a ?punching machine?. These holes are cut out and the remaining steel piece is bent down in the u-beam.
Just In Time : Effektivisering av materialflöden med hjälp av principer från Inventory Management och Production Management
AbstractManagement is a field that started getting attention in the beginning of the 20th century by Frederick Taylor. His publication is called the Principles of Scientific Management and is based on the principles of using scientific methods to find the best way of conducting each operation within a production facility. Many of Taylor?s principles may appear obsolete today but the matter of an effective material flow is still highly current. Efficiency is the relationship between the input into an operation and its result.
Hylshantering samt flödesanalys
Trioplanex International AB is a part of the group Trioplast Industrier AB, which produces packaging materials for the film and hygiene industry. The group is active throughout Europe, where most of the production is located in Sweden, with head office in Smålandsstenar. Operations in Landskrona consist of Trioplanex International AB and Trioplast Landskrona.Semi-finished articles consisting of paper cores, so called bobbins, give rise to a high amount of core waste in any form of core cutting. The objective of the report is to map out all core waste and illustrate the material flow with regard to present layout and equipment.In the beginning of the project an analysis of the current process was carried out with focus on the cutting equipment. A case study in the form of an improvement work took place in order to reduce the causes which had the biggest impact on existing machinery.Improvement proposals were discussed by the author together with supervisor, assigner and other parties involved.
Naturhänsyn på certifierade privata skogsfastigheter : en jämförelse i praktiken mellan FSC och PEFC i Sydsverige
Nature conservation on certified small private forest owners- a comparison
between the two certification systems FSC and PEFC in southern Sweden
Today two different certification systems are used in Sweden to certify forest, FSC (Forest Stewardship Council) and PEFC (Pan European Forest Certification). During the last years certification of forests in general and different certification systems have frequently been debated. FSC is a globally widespread system and about 10 million ha out of 23 million ha Swedish forest is FSC-certified. The FSC-standard is mainly used by major forest companies and to some extent also by smaller private forest owners. PEFC is a European system and about 2 million ha Swedish forests is PEFC-certified today.
Underliv och överordning ? En diskursanalys om motståndsaktivisternas tal om kvinnlig könsstympning/omskärelse i Tanzania
The aim of this study is to analyze the discourses of activists who work against female genital mutilation/cutting (FGM/C) in Tanzania. The study focus on the discourses that arise during interviews about FGM/C with five activists. To examine this we asked the following questions: What discourses are presented in the interviews? How do these discourses interact together ? are there any discourse conflicts? How do the activists talk about FGM/C in comparison to our western view? The study is based on discourse theory. We also use feminism and postcolonialism as theories in our analyze.