SammanfattningPendelmetoden eller ?Pendulum Friction Tester? är en bärbar friktionsmätningsmetod för både gångytor och vägbanor. Den har funnits sedan 1940-talet men modifierades på 1960-talet med bland annat en ny skala som kallas för PTV (Pendulum Test Value). Ju halare ett ytmaterial är desto lägre PTV.Metoden använder bland annat två alternativa glidklackar kallade slider 57 respektive slider 96. Det är känt att PTV för slider 57 är temperaturberoende och minskar med ökande temperatur.

Arbetets syfte är att göra en aktualiserad framställning av ämnet trädkult. En viktig del av syftet har också varit att göra en mera heltäckande materialgenomgång än tidigare studier. Framställningen kommer huvudsakligen att beröra den fornskandinaviska religionen men utblickar kommer att bli nödvändiga för att komplettera materialet. Således kommer även kontinentalgermanska och samiska områden att beröras, kontinentalgermanskt område något utförligare, samiskt område i form av ett exempel. Visserligen kommer arbetet i mycket att ha karaktären av en betraktelse.

This master thesis reviews advances in detection and diagnosis of static friction (stiction) in control valves. Control valves suffering from stiction results in oscillating control loops which in turn decreases both the process stability and reliability. Perstorp AB sees a necessity to automatically detect stiction in valves before the effects of the malfunctioning valves have become too severe. This thesis presents an introduction to maintenance, control loops and how stiction in valves can affect performance of control loops.A selection of methods presented in the literature are introduced and examined using normal operating data from the site in Perstorp. Common for all selected methods is their intuitive ideas and that they are based on normal operating data and minimum amount of process knowledge.

This thesis approaches the problem of estimating the arm angles of an industrial robot with flexibilities in joints and links. Due to cost-cutting efforts in the industrial robots industry, weaker components and more cost-effective structures have been introduced which in turn has led to problems with flexibilities, nonlinearities and friction. In order to handle these challenging dynamic problems and achieve high accuracy this study introduces state observers to estimate the tool position.The observers use measurements of the motor angles and an accelerometer and the different evaluated observers are based on an Extended Kalman Filter and a deterministic variant. They have been evaluated in experiments on an industrial robot with two degrees of freedom. The experimental verification shows that the state estimates can be highly accurate for medium frequency motions, ranging from 3-30Hz.

The aim of this thesis was to investigate if the robotized welding method FSW (Friction Stir Welding) could be applied for joining a rotating structure in an aero engine at Volvo Aero Corporation. FSW is expected to introduce less defects than today?s welding methods and could therefore be suitable for critical aero components. The material is the nickel based alloy Inconel 718, however a material experimentation is outside the scope of this report.The main goal of this study is to verify if the ESAB ROSIO robot based FSW-system has a suitable work space to be able to weld the rotating structure, and if the welding tool has accessibility to the joints. The FSW-process needs a rigid fixture, and a number of fix-ture concepts are presented based on a proposed weld sequence.

Today the Internet is used more and more as a transportation for information. Much of the information is confidential and should not be read by those not privileged. To protect the information from unauthorized access cryptography can be applied. The cryptography algorithms in use today all have their pros and cons. They are therefore suited for different applications.

Today the Internet is used more and more as a transportation for information. Much of the information is confidential and should not be read by those not privileged. To protect the information from unauthorized access cryptography can be applied. The cryptography algorithms in use today all have their pros and cons. They are therefore suited for different applications.

In this thesis a concept for floor hatches for foam pits has been developed. Since there is an existing solution that is powered by hydraulics and is expensive, the goal was to develop a cheaper solution, as simple as possible.A number of different concepts were developed and evaluated. A concept with five sections that are pulled to the side and stacked on each other was chosen as it was thought to have the lowest risk of crush injuries and to be easiest to manage and control. In the opening behind the foam mattress a lifting table is placed to regulate the height of the stacked sections.To be allowed to be installed in the floor of sports halls the sections must be dimensioned according to the construction standards for these types of buildings. Different dimensions of beams in steel and wood materials were evaluated and of those, who lived up to the requirements of the standard, a concept was chosen.

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.

Transient driftförhållande blir allt mer intressant för forskare och tillverkare och de största svårigheterna är att minska emissionerna utan att påverka bränsleförbrukningen eller motorns respons vid gaspådrag negativt. Huvudmålet med det här examensarbetet var utvärdera olika metoder för att mäta NOx och antal partiklar med hög tidsupplösning för att möjliggöra studier av emissioner under transient driftförhållande.I arbetet har en Horiba MEXA 120NOx NOx-sensor studerats med avseende på linearitet, mätsäkerhet och responstid. Försök för att öka noggrannheten har också gjorts genom att kompensera för varierande skalfaktor för utsignalen och för responstiden.Ett spädsytem har arbetats fram för att ge hög tidsupplösning och god repeterbarhet. I detta ingick en Rotating Disc spädare och en två-stegs Dekati spädare. Spädsystemet var kopplat till en TSI Ultrafine Condensation Particle Counter 3025 A (CPC) och var nödvändigt för att hålla koncentrationen inom det mätbara området.

This is a final thesis done at BT, considering one of their forklift truck models called Reflex. The first part of this report is about a preliminary investigation investigating what kind of diagnostic systems BTwants to use, and also which demands there are to meet all expectations on such system. Secondly a diagnostic system, which will show if the drive wheel is worn out, will be presented. In the preliminary investigation, two kinds of diagnostic systems were mentioned. These were Model based diagnosis and Predictive analysis.

Background: The majority of the occupational accidents and work-related diseases at Swedish workplaces occur due to poor ergonomics during lifts and transportation of objects. The most common consequence of poor ergonomic conditions is low back pain (LBP) and the risk of developing LBP increases as the mechanical loading on the intervertebral disks grows. This study has investigated the biomechanical loading in the low back during two different types of patient lifts. The first lift (lift A) is developed by Modern Arbetsteknik (MA) and the second lift (lift B) is a common lifting technique among care workers. Objectives: The aim of the study was to identify any advantages or disadvantages with MA?s lift, regarding shear and compression forces in the L5/S1 disc.

AbstractSyfte: Uppsatsen undersöker det första fysiska mötet mellan kunden och fastighetsmäklaren. Hur påverkar första intrycket kundens beslut och fortsatta relation med fastighetsmäklaren?Metod: Jag har använt mig av en kvalitativ metod då jag anser att det är en passande metod för denna studie då den är baserad på elva stycken telefonintervjuer med människor som har sålt med en fastighetsmäklare. Teorier om första intrycket har studerats och dessa teorier jämförs sedan med empirin för att dra slutsatser.Resultat & slutsats: Valet av fastighetsmäklare varierar från säljare till säljare då de lägger fokus på olika saker. Däremot verkar de vara överens om att det är positivt om mäklaren ser välvårdad ut, är noggrann och tydlig i sitt sätt att tala och inte är "för på".

Omkring 10-20 % av personer med lumbalt diskbråck opereras. Operationen syftar främst till att behandla utstrålande smärta i nedre extremiteter. Beteenderelaterade faktorer kan påverka smärtupplevelsen vid långvariga smärttillstånd och viss forskning finns om hur resultatet av diskbråcksoperation påverkas av olika biopsykosociala faktorer.Syftet med denna studie var att undersöka hur smärtintensitet var associerat till vissa beteenderelaterade faktorer före och två år efter lumbal diskbråcksoperation, samt om dessa faktorer preoperativt kan predicera smärta efter diskbråcksoperation. Studien är en longitudinell deskriptiv kohortstudie där associationer analyseras. Data samlades in med en enkät före och efter operationen.Preoperativt besvarade 59 personer enkäten, två år senare upplevde 20 personer ingen smärta och besvarade därför inte de beteenderelaterade frågorna.

Gliding and sealing functions in Öhlins shock absorbing systems sets great demands onthe contacting surfaces. In this particular case, the bushings and the sealings on acylinder piston. The surface wanted is a surface with both low frictional forces and smallleakage. This study was done with the goals of investigating and determining existingsurfaces due to the frictional force and leakage. How can we in an easy mannerdescribe these?A number of ten front forks were part of a main study.