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.

This review paper summaries scientific research about horse thermoregulation and the consequences of using a blanket. Horse owners put blankets on their horses to protect them when they are clipped, to protect them from bugs, to keep them clean and so on. This can have consequences for the horse which their owners might be unaware of. I have tried to answer following questions by searching the available scientific literature; ? How can the horse maintain thermoregulation? ? Is there a risk of suffering when horses wear a blanket? ? Is there a risk of suffering when horses do not wear a blanket? ? How can animal inspectors estimate the welfare of horses when they wear or do not wear a blanket? My result shows that horses who wear a blanket have an increased risk of becoming overheated, develop a chafing, have an increased exposure hazard and have a restrained natural behaviour.

This project has as main goal to study the influence of the coating thickness, deposited by arc-PVD- technology, on the wear resistance of coated cemented carbide inserts in three different turning operations. An additional effort has also been made to develop a new test method for evaluating flank wear resistance. Three different coating types (Coating A, Coating B and Coating C) have been studied in three distinctive thicknesses (2, 4 and 6 µm) for each type. For two of the coating types (Coating A and B) special studies has been done with the thickest coating, creating two additional coating versions of the thickest coating, by changing various deposition parameters, with the aim to enhance the cohesive properties of the coating and lower the residual stresses at the cutting edge. The results show increased crater wear resistance with increased coating thickness for all coating types, but the amount of increase changes with coating type (Coating A>B>C).

Test bench for air bearingsThis thesis work consisted of bringing forward and defining the test parameters relevant for a test bench and constructing a test bench that can test and verify the largest existing air bearings that are of use in Micronic Laser Systems AB machines. Because the knowledge about air bearings is limited it is thought that with the help of the test bench the knowledge would increase and in that way improve the air bearings.After learning more about air bearings and their purpose at Micronic Laser Systems AB, I started the concept phase for the test bench. For each part in the test bench I consulted my two tutors, Torbjörn Hedevärn and Johan Bergqvist, at Micronic Laser Systems AB. The final concepts where documented as 3D-modells in Solidworks and some of them have been tested in Solidworks FEM-program.The test bench is designed so that, with the help of a pneumatic cylinder, 25 kilo weights are placed on the air bearing to test its stiffness, damping and the pressure performance under its surface area. To test these parameters the test bench has to have a pressure meter, accelerometer and a microcator.

During this master thesis, wear and friction properties for the high-temperature alloy Kanthal APMT were studied. The results were also compared to 253MA. The initial tests showed, among other things, that the surface fineness of the muffle tubes matters in real applications like conveyor belts. A 253MA-sample wear-tested against a 253MA-tube showed lowest wear at 900°C while a pre-oxidized APMT-sample wear-tested against a APMT-tube had the lowest mean value of the friction force at 1100°C, compared to all other tests..

Aim: The aim of this study was to examine and explain the various methods available to rate the erosion damage, and on which teeth and tooth surfaces of erosion damage mostly occurs in children and adolescents.Method: A literature review was conducted, based on 15 scientific articles that have been reviewed, evaluated and analyzed. Articles were searched for in the database PubMed.Result: Six of the articles used the TWI (tooth wear index), which is an index to diagnose the tooth wear in the primary and permanent dentition. Eight articles used other indices as they considered that the TWI was not sufficiently developed to register the degree of tooth wear on some teeth. Tooth wear in the primary dentition occurs most often in the canines and incisors. Tooth wear in the permanent dentition was found in the literature to be mostly occurring on the occlusal / incisal surfaces of all teeth and tooth surfaces.LyssnaConclusion: There is no common index in the articles but many of them use the TWI.

The agricultural plantingmachines are used just a few weeks every year. That means that the supply of service and spare parts have to be good to make the timeliness costs low at the agricultural hard working periods. The machines wear down successivly when they are used. The wear is harder on some parts than the others on a machine. Spare parts can be dicided into consumables.

IRB 340, Flexpicker is an industrial robot used for sorting, packaging and the handling of details up to two kg. The Flexpicker is a delta robot, meaning that it with three arms controls a triangular plate, swivel, in a work area shaped like a cylinder. Joints using plain bearings connect the arms.The plain bearing in use today consists of a plastic ring which slides against a hard anodized joint ball. Despite the fact that the plastic contain friction-lowering additives, the bearing needs to be lubricated to prevent noise. Because the robot is used in food and drug handling environments, where the demands on hygiene are set very high, the robot is often washed.

Nowadays naval units are participating in international missions, where new and in many cases tougher conditions will affect their propulsion. This essay deals with some of the now developed nanostructure coatings and gives a presentation of how the coatings could function on some exposed parts of the naval powertrain. The essay investigates the possibility that the coatings can be used as a protective layer that will reduce or prevent wear on selected parts of the naval powertrains. As a basis for the essay, nanotechnology is described, as well as different reasons that wear occurs and application techniques for coatings The conclusion is that nanostructured coatings can be applied and provide a much better result on hardness and wear resistance as of naval powertrains compared to micro-structural coatings, both for manufacturing and renovation. The essay presents a few examples of the military utility of the nanostructure coatings as well as suggestions for further research..

This report discusses questions concerning wear on forest roads. The purpose of the work is to investigate if the wear on the roads will decrease when the speed limit gets lower for the trucks that transport the wood. A normal forest road, class B, was used in the study. In total 5000 m3f timber was transported on the road. Data about the road was measured with a profilograph car before and after the timber transport.

Volvo Cars in Skövde manufacture and assemble Volvo engines. When attaching the ignition coil to all 4-cylinder engines, a special mounting tool is required. This mounting tool is currently manufactured from injection-molded polyoxymethylene (POM), a thermoplastic. It has been noted that the life span of the tool is shortened as a result of abrasive wear that occurs during the attachment process of the ignition coil.An investigation of the possibility of manufacturing the mounting tool with a 3D-printer is undertaken in cooperation with ÅF, a consultant to Volvo Cars. A literature study is first presented to introduce broader knowledge on the subject.

Nowadays naval units are participating in international missions, where new and in many cases tougher conditions will affect their propulsion. This essay deals with some of the now developed nanostructure coatings and gives a presentation of how the coatings could function on some exposed parts of the naval powertrain. The essay investigates the possibility that the coatings can be used as a protective layer that will reduce or prevent wear on selected parts of the naval powertrains. As a basis for the essay, nanotechnology is described, as well as different reasons that wear occurs and application techniques for coatings The conclusion is that nanostructured coatings can be applied and provide a much better result on hardness and wear resistance as of naval powertrains compared to micro-structural coatings, both for manufacturing and renovation. The essay presents a few examples of the military utility of the nanostructure coatings as well as suggestions for further research..

Future emission legislation puts great emphasis on increasing the efficiency of the engine, thereby reducing fuel consumption. The tribological contact between cylinder liner and piston ring is where an great amount of energy is lost due to friction, and by reducing these losses an reduction in fuel consumption can be achieved.The aim of this thesis was to evaluate the tested piston ring coatings against a plasma sprayed cylinder liner and rank these combinations of materials for friction and wear resistance. The coatings that were tested was Cr + Al2O3, (Al,Cr)N, two types of CrN and WC / C.The experimental tests were performed with a so-called pin-plate, where used oil with addition of an acidic mixture of sulfuric and nitric acid to mimic the acidic condensate formed when exhausts recirculate, were added with a continuous flow. The results were then analyzed by weighing, studies by optical microscopy and scanning electron microscopy (SEM) and profile measurements.The results from each material combination were that the plasma coated cylinder liner wears too aggressively in order to yield a ranking of the piston ring coatings based on the parameters of friction and wear resistance. It is therefore proposed that an alternative coating on the cylinder liner should be developed, lacking the large abrasive wear on piston rings and that can withstand the corrosive environment resulting in engines equipped with EGR.

The system tungsten-oxygen has potential of being suitable for decorative coatings since ceramic coatings are often hard and wear resistant, and since modulations in oxygen content or incorporation of small ions could give bright colours. The aim of this report was to investigate the relationship between process parameters and  the properties of the films, with the wear resistance being of special interest.Samples with tungsten to oxygen ratios in the range of 100:0 to 25:75 at% were made using reactive sputter deposition, either with constant gas flow, or gas flow controlled by optical emission of the plasma. The hysteresis of the system, which means that a certain gas flow will cause different pressure and/or target voltage depending on in what way the flow is reached, makes it interesting to control the process where the system makes the steep change from metallic tungsten to ceramic tungsten oxide. This is difficult and thus requires precise control equipment.The samples were analysed using X-ray diffraction, X-ray photoelectron spectroscopy and an empirical wear test suitable for small components like cell phone cover for example, in order to characterize the structure, composition and wear resistance of the coatings. The results could be divided into three groups: (I) tungsten-like, with very low oxygen content; (II) mixed phase and (III) tungsten oxide like, with oxygen content close to 75 at%.

There is always a need for more effective ways to store energy in order to reduce the human impact on the environment. One step on the way can be the use of flywheels as kinetic energy storage devices. Low frictional losses are essential for a flywheel to be effective. To minimize these losses active magnetic bearings (AMB) can be used to keep the shaft centered instead of the more conventional ball-bearings. AMBs use actuators and a fast control system that needs correct and noise-free measurement data of the shaft position and the current in the actuators to work properly.This thesis explains the process of constructing power electronics and a current measurement system for active magnetic bearings (AMB).