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119 Uppsatser om Abrasive wear - Sida 2 av 8
Slitundersökning för jordbearbetning och sådd :
In this study we try to focus on the costs for wear parts on different type of soil tillage machines and at Väderstad Rapid drilling machine. We have studied some of the leading types of cultivators and disk harrows. Among the cultivators we have investigated Väderstad Cultus, Dalbo Dinkomax, Horsch Tiger and Terrano. At disk harrow we have looked at Amazone Catros and Väderstad Carrier.
We have made more detailed study on costs for wear parts, working depth, driving speed and diesel consumption.
Utredning av frekvensregleringens påverkan på mekanisk utrustning i en kaplanturbin
As a consequence of increasing wind power installations in the Nordic grid the last years, the need for regulating power has become larger. In the Nordic grid, regulating power is mainly provided by hydro power. One part of the regulating power is called frequency control, which ensures that the grid frequency is stable and close to 50 Hz.However, setting the turbine into frequency controlled operation may cause stress and wear of the components in the mechanical control system. Frequency controlling implies large and frequent servo forces and longer travelling distance of the sliding bearings in the Kaplan turbine.Based on one selected Kaplan turbine, Selsfors G1, measurements and MATLAB calculations have been performed in order to determine forces and movements of the linkage system. With these forces and movements as input, stresses and fatigue have been determined as well as sliding distances, bearing pressures and wear of bearings during a typical lifetime of 40 years.The results indicate that no severe wear exists on the bearings during 40 years of service.
Faktorer som påverkar Vänerns öppna sandstränder och möjligheterna för hög biologisk mångfald ? med mossor som indikatorer på igenväxning
The sandy beaches of Vänern are threatened by overgrowth and thereby the biodiversity is at high risk to decline. This study is based on an inventory of vegetation of overgrowth character and mosses. The frequency and spread of mosses is perceived as an indication of initial or present overgrowth. External factors that have been taken into consideration are wind-, wave- and ice erosion, the slope of the beach, wear and grade of exposure. The purpose of the investigation is to control the beaches grade of overgrowth and find out which external factor is of most importance for the maintenance of the biotope. The results show that the beaches environment is affected by the slope of the beach, grade of exposure, size, wear and overgrowth.
Formulering och provning av en ny typ av sågkedjeolja
Formulation and testing of a new type of chainsaw lubricantThe company Agro Oil has come up with the idea of developing an environmentally adapted chainsaw lubricant with a new unusual base fluid. A field test with a tree-harvester shows unsatisfactory low temperature properties and high wear. In this work the viscosity, price and pour point of different combinations of the given base fluid and three other base fluids have been investigated. Desired viscosity and price are determined for different formulations. The new lubricants tested show lower pour points than almost all products on the Swedish market.A test equipment has been developed to investigate the wear.
Utveckling av säte till kulventil SKV
This report contains a degree project made by the mechanical engineering students Lennart Andersson and Daniel Jansson. The project has performed in assignment by SOMAS Valves AB in Säffle. SOMAS are leading in development on control and on/off valves. To maintain this position they always want to improve their products. One way in this development is valves that are more tightened.The purpose with our project was to investigate another seat design on a HiCo (High Cobalt Alloy) seat to a SKV 150 PN 25 valve and compare this to an original HiCo seat.By modifying the seat on a ball valve we want to achieve a valve that leaks lesser then a valve whit original seat.
Långsiktigt spårväxelunderhåll - Förutsättningar och möjligheter
Due to their complexity and heavy wear from rail traffic, switches are a sensitive part of the railway infrastructure and moreover expensive to maintain. Furthermore, increasing railway traffic not only accelerates the wear rate but also obstructs the necessary maintenance measures. This paper examines the opportunities for a transition to a long-term maintenance strategy in the Swedish railway network. It contains a study of the maintenance strategy of Banverket, and also analyses statistics of errors in the railway infrastructure. The survey was completed utilising interviews with infrastructure managers, maintenance contractors, planners of railway operations and the Banverket material service department.
The effect of hoof trimming on dairy cows´ behaviour, locomotion and production
The Swedish dairy production today consists of big farms and different housing systems are in use. These systems put demands on the cows? ability to cope with the environment and one challenge is the claw health in the herds. Some claw lesions that are frequently observed are foot rot, hemorrhages, digital dermatitis and sole ulcers, which can be caused by, for example, the claws? environment and the flooring type used.
Hårdfräsning i verktygsstål : Förslitning av skäregg
This thesis work is made by Torbjörn Johansson on Karlstad University for Uddeholms AB. The assignment in this thesis work was to investigate tough cutting in three different tool steels: Vanadis 4 Extra, Vancron 40 and Sverker 21. The research was to compare the wear of the tool after cutting in each one of the tool steel alloys. The research was also made to see if the tool cutting in Vancron 40 has a better wear than the tool cutting in Vanadis 4 Extra and also compare the results with Sverker 21. All three of these alloys are a part of Uddeholms AB:s range of products, and is used in applications like forming tools and knife tools. Vancron 40 is a powder steel with a very good combination of mechanical properties like ductility, adhesive strength and hardness.
En argumentation om berättelser - En studie om effektivitet och reklamkapital för repetitionsstrategier
Despite narrative advertising being an increasingly popular strategy among brands today, little research has examined the different expressions of repetition variation strategy in comparison to its alternative, argumentative advertising. Still unexplained is whether the appreciation and recognition created from successful storytelling-based commercial campaigns is a result of execution or the format itself. This study aims to investigate four repetition variation strategies, three narratives and one argumentative, to determine which one is the most effective and also which one that generates the highest advertising equity. An experiment was conducted through exposing four groups of Swedish High School students to text-based advertising manuscripts customized after format, where each group was exposed to ads on two separate occasions. The result showed evidence of narrative advertising being easier to comprehend, which according to theory should lead to higher advertising effectiveness.
Rutiner och riktlinjer för förebyggande av smitta på svenska djursjukhus och kliniker
To be able to give optimal care to patients in small animal hospitals, we have to have knowledge about how to prevent the spread of infection. An important part in this is hand hygiene routines. We have to clean hands whenever they are visibly dirty, and disinfect them regularly in between. Another important part is the cleaning and disinfection of the environment in the clinic, and also the cleaning, disinfection and sterilization of medical instruments. Other important parts are isolation of patients with known infections, to wear clothes with short sleeves and to wash them at least once daily, to wear gloves, having short nails and not wearing jewelry when working.
Integrating Forward by Going E-commerce - A study of the Fashion Industry and the Development Phase of an Internet Establishment
The purpose of this thesis is to outline an appropriate model in order for companies to successfully act and compete physically as wholesalers at the same time as acting on the virtual market by selling directly to the end consumer. The approach of this thesis is hermeneutical and abductive with elements of hypothetically deductive approach. Our research has a qualitative research strategy based on case studies and interviews as well as on secondary data. Interviews were conducted with the case company JaymJay Wear AB as well as with other companies, so called mini cases. The secondary data consists mainly of textbooks, web sites and journals.
Spänningsanalys av axel-länkmekanism på borr-rigg
This master thesis is intended to give an increased understanding of the stress state in an axle, which is assembled in one of Atlas Copco?s mountain drilling rigs. The main problems investigated were how the axle is affected when the bearing is worn, when the pretension is varied, and how to dimension the axle. Answers to these questions were found by using hand calculations, practical testing and with Finite Element analyzes. The dimensioning of the axle is currently based on the bending stress, but the author?s opinion is that the axle should be dimensioned considering the equivalent stress.
Drivaxeltrycksreglering hos tunga fordon : För en ökad framkomlighet vid vinterförhållanden
Heavy duty vehicles often have problems with traction during the winter periods. For vehicles that can lift tag axles it is possible to increase the normal force on the driven axle by lifting one or more tag axles, this will then increase the propulsive force of friction. This however increases wear on both road and vehicle. A possibility to reduce the wear while achieving nearly equivalent traction compared to lifted tag axles is to allow the vehicle to regulate the normal force by lowering the pressure in the air suspension associated with the tag axles or by the lifting of these axles. The vehicle would then by itself be able to set just the right amount of normal force on the drive wheels to avoid unnecessarily high normal forces while maintaining sufficient traction.The purpose of the report is to find out which parameters affect heavy duty vehicles when driving on slippery slopes and how traction can be improved.
Klövform och klövsjukdomar hos intensivt uppfödda köttrastjurar :
The top selection of Swedish beef bulls are evaluated yearly by Svensk Köttrasprövning AB at Gismestad. The bulls are selected from six different breeds; Angus, Blonde d´Aquitaine, Charolais, Hereford, Limousin and Simmental, and are kept on straw bedding apart from a concrete alley in front of the feeding area during the six months of evaluation period. The bulls are evaluated according to their fertility scores, growth, exterior and temperament and the exterior, body posture and claw conformation reflect important qualities for their longevity. In spite of good values for fertility, it has been noticed in the last years that the fertility results and longevity have been unsatisfactory and claw and/or bone disorders have been suspected as a contributory cause.
Persson et al. (2007) studied breeding bulls from Gismestad and other places, which had been slaughtered due to poor fertility (no pregnancies in the herd during their last year in service).
Oljefilmens tjocklek mellan kolvring och cylinderlopp
Hägglunds Drives in Mellansel, Sweden, manufacture radial piston hydraulic motors foremostwithin applications in the industry. These motors have several sliding contacts, one of these, isthe contact between piston ring and cylinder bore. The radial piston hydraulic motors advantageis to produce high torque in very low rotation velocity, this result in that the maximum slidingvelocity between piston ring and cylinder bore, during the whole stroke, is very low. Theconsequence of this low sliding velocity is that the contact between piston ring and cylinderbore, during the whole stroke, is bound to the boundary lubrication regime. This result in, thatthe piston ring is exposed to wear, thus affect the service life of the complete hydraulic motor.To minimize wear of piston ring, it is essential to determine the oil film thickness between thepiston ring and cylinder bore.