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175 Uppsatser om Velocity zones - Sida 5 av 12

Trädens utveckling efter att de har lämnats som naturhänsyn : tillväxt, mortalitet och strukturell förändring 6-18 år efter avverkning

Today green tree retention, together with leaving dead wood, is a common practice with the aim to reduce negative impacts on biodiversity and environment due to clear-felling. To better understand whether this conservation practice also makes a long-term difference, it is important to know what happens to these trees after harvest. Few studies have made an assessment of what happens to retention trees over a longer time period. In this study I inventoried retention trees that were left at clear-cuts six, twelve and eighteen years ago. I carried out a re-inventory of 57 retention patches (divided into free-standing tree groups, small swamp forests and edge zones) and free standing dead trees, spread over 25 previous clear-cuts in central Sweden.

Går det att mäta blodtryck med fotopletysmografi och bioakustisk sensor i kombination?

The aim of the work was to investigate the possibility to combine information from PPG and bio-acoustic technology to extract information that is related to the blood pressure. The measurements have been carried out with several different configurations. First the relation between arterial sounds and the PPG-signal was studied. After those measurements with both PPG and the bio- acoustic technique was concluded on people in different positions and after riding a bike. The goal was to vary the blood pressure.

Predicting spawning bed erosion and longevity : a case study in tributaries to river Vindelälven, northern Sweden

Timber floating operations in Scandinavia during the 19th and 20th centuries has contributed to severe negative impacts on riverine ecosystems. Increase in water velocity and lack of stream bed heterogeneity as a result of stream channelization lead to increased bed load transport. Since availability and recruitment of new suitable spawning substrate in Scandinavian watercourses is sparse, spawning habitats for salmonids has become a scarce commodity. Lately, increasingly more attention has been given to the recreation and improvement of brown trout (Salmo trutta) spawning habitats in restoration projects. While much of the research on spawning habitat has been focused on evaluation of the influence that the constructed spawning grounds have on fish populations, few studies have been conducted to evaluate the persistence of these constructions over time. I evaluate erosion of constructed spawning beds as an effect of sediment transport attributable to water discharge.

Modellering av hydrauliskt aktuatorsystem

This report treats a Master Thesis performed at Scania CV AB. The task was to create a computer model of a hydraulic actuator system in the software AVL Hydsim. The system consists of two spring-loaded masses with surrounding hydraulic components. The purpose of the model is to study phenomenon and problems in the system, as well as to be a support in the development of the system. It is not supposed to be used to study absolute values in its current form.

Glacialgeologi i fjällranden : Undersökning för att spåra värdberget till ett zinkmineraliserat block

The valleys southwest of Storuman has been exploration targets for sulfide mineralizationslike the Laisvall Pb-Zn deposit since the late 1900 when several mineralized boulders wherefound. No previous glaciogeological survey has been made. This report focus on thedirections of local paleoiceflows and glacial transportation in the area of Skikkisjön, thelocation of the westernmost mineralized boulder, found in 2010. The aim of this study hasbeen to create a picture of the glaciogeological evolution of the area in order to determinatepossible hostrock areas. My results suggest that the geomorphology and transportationoccurred during a western icedivide located in the nearby mountainrange.

Utvärdering av traktplanering på Holmen Skog

This study has been performed with the help of forest machine operators in order to improve the forestry planning at Holmen Skog Örnsköldsvik-region. For Holmen Skog forestry planning is basic for a successful forestry. In a survey I have investigated what can be improved in some areas that are planned for harvesting. The result of the investigation will be used to support the machine operators as much as possible. The study has generated 49.5 % of responses and because of this low response rate, no clear conclusions to anyone else except the responding machine operators can be drawn. It has been proved that there are some details in the forestry planning system that are inadequate, such as marked routs for trails, tractor paths and buffer zones against streams. The quality of forestry planning varies greatly between different locations, as much as 50 % of the responding machine operators thought so. Over 40 % of the responding machine operators claim that the information from Holmen is insufficient. One thing that would improve the forestry planning within Holmen would be to educate all forestry planners and then do continuous follow-ups..

Sensorfusion av GPS och IMU för en racingtillämpning

AIMS AB is a Swedish company that develops and sells inertial sensor systems. A new product is under research which basically is an aided inertial navigation system where unwanted drift is eliminated. This can be done by integrating a GPS reciever into the system and fuse measurement data from GPS and IMU. Such a product is useful in racing, where engineers always are searching for the optimal performance and the shortest lap times. Today the only feedback the engineers and mechanics get from their work is the driver?s comments and lap times.

FPGA baserad PWM-styrning av BLDC-motorer

This thesis work contains a litterature study about electrical motors in general and how PWM-patterns for brushless DC-motors can be made. A suitable method has been implemented as a simulation model in VHDL. A simulation model of a brushless DC-motor which describes the phasecurrents, torque and angular velocity has also been made. The motor model made simulations easier for the complete PWM-system. The design was synthesised and tested with a prototypeboard including a SPARTAN II FPGA.

Optimal bredbandig vågform framtagen genom generaliserad osäkerhetsfunktion

The waveform of a radar signal affects the resolution in velocity and distance. The ambiguity function is used as an aid for analysing narrow band radar signals simultaneously in time and frequency. An analysing tool for wide band radar signals is missing.This thesis describes a generalised ambiguity function to be utilised for study of wide band signals. Waveforms are further synthesised with help of the developed analysing tool. The aim is to start with a certain ambiguity function and find a waveform that reproduces the same ambiguity function.Mathematical formulas are presented and implemented in Matlab to produce the wide band ambiguity function.

Clover (Trifolium spp) gamefields : forage production, utilization by ungulates and browsing on adjacent forest

Wildlife is a valuable and renewable resource that promotes economical, ecological and social values. These values are important for developing and maintaining many rural societies. However, growing ungulate populations have led to increased browsing pressure on valuable forest trees and crops. Previous studies have proposed supplementary feeding and gamefields as potential methods for controlling the ungulate foraging and reducing browsing damage by providing other attractive food resources. However, quantitative estimates of potential biomass production of various gamefield crops and browsing pressure on the surrounding forest have been lacking.

Arkeologisk landskapsanalys och prospektering av bebyggelselämningar och gravfält vid Alsike hage

This paper deals with archaeological prospecting for the purpose of finding a prehistoric settlement in Alsike hage, Alsike parish, Uppland. The methods being used are soil phosphate analysis, electromagnetic survey and settlement analysis. Two 20x20 meters areas have been prospected. As Alsike hage contains several late Iron Age burial fields, large splendid zones for settlement location, closeness to water as well as farmland there was a hope of locating remains of prehistoric settlement in the area. None of the prospected areas showed any distinct evidence of settlement remains.

Effekter av spädningsvätska på motilitet och fertilitet hos hingstsperma : en jämförelse av subjektiv motilitetsbedömning och QualispermTM

At SLU, Divison of Reproduction, Dept of Clinical Science, there is an ongoing project on the development and evaluation of new methods for the assessment of stallion semen quality. This EEF-study, which is a part of that larger project, has focused on the effects on motility and fertility of stallion semen of two different extenders and selection. Both an objective method and a subjective method for analysis have been used and compared in the study. The increase in the use of artificial insemination with cooled semen in Swedish horse breeding over the last decade is thought to play a part in declining foaling rates (Kareskoski et al, 2006, Kuisma et al, 2006). This calls for better evaluation methods of semen quality since cooling and transportation put higher demands on semen quality in order to maintain fertility (Aurich, 2005).

Excel-baserad beräkning och dokumentation av distansskyddsinställningar

This is a master thesis work carried out at the Department of Energy and Environment atthe Division of Electric Power Engineering. The master thesis work describes the theoryof distance protection relaying in 130 kV meshed distribution networks. The main aim ofthe thesis was to construct an Excel application for calculation and documentation of thesettings for distance protection relays. The program is based on general methods forcalculating settings of the different zones for the distance relay and presents the settingsin simple graphics using quadrilateral characteristics.The reason for building an Excel based application is the great variety of distanceprotection relays in live networks. The manufacturers of distance protection relays makeprogram for documentation available, however, they are based on the typical settings forthe specific relays.

Att färdas i symbios : ett gång -och cykelstråk anpassat efter trafikanternas rörelsemönster och behov

The aim of this paper is to examine the layout of public spaces and its effect on human behavior with focus on the relation between pedestrians and cyclists movement patterns in a specific path. The study emanates from the security aspect of pedestrians and cyclists, and builds upon previous theories and empirical studies about perception, security, information design, environmental psychology and behavior. The result shows that individual behavior and movement pattern differs with age, purpose, physical- and other conditions, and layout of the surroundings. A design proposal for improved layout of a path and a node between different oncoming paths has been developed to aid the users? needs, where a separation of walkways and bike lanes forms zones of security for the purpose of better orientation and a better flow between the users..

Undersökning av mätsystem och regulatorstrukturer för industriella tillämpningar

This thesis is divided in to two different parts. The first part includes examination of the measurementsystem of an industrial robot using a resolver sensor. The main focus is on methods for suppressing noise in the angularvelocity signal without increasing timedelay. Five different methods are investigated. Three of these are based on oversampling: burstsamplingmethod, meanvaluemethod and correlationmethod.

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