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58 Uppsatser om Bending stiffness - Sida 2 av 4
Utvärdering av en Magnetic Harmonic Traction Drive
In this report a new gear concept is evaluated using the magnetic finite element method (FEM)software MagNet and Ansys as well as the mechanical FEM software Abaqus. The gear conceptis evaluated in terms of maximum torque capability, torsional stiffness, gear ratio and efficiency.ABB Corporate Research has proposed a new gear concept which should be less expensive thangearboxes used today. The new concept is called aMagnetic Harmonic Traction Drive and usesthe principles of a harmonic drive gear to achieve a high reduction ratio. The gear conceptreplaces the wave generator used in traditional harmonic drives with magnets and uses tractioninstead of gear teeth to transfer the torque. The main components in the gearbox are the magnets,the flexspline, the magnetic portion and the circular spline.
Vegetarisk kost - ett möjligt behandlingskomplement för symtomlindring vid reumatoid artrit?
Sahlgrenska Academyat University of GothenburgDepartment of Internal Medicine and Clinical NutritionAbstractTitle: A vegetarian diet, a possible treatment complement for relief of symptoms ofrheumatoid arthritis? A systematic review.Author: Alexandra Ahlsén and Caroline ForsbergSupervisor: Mette AxelsenExaminer: Anna WinkvistProgramme: Dietician study programme, 180/240 ECTSType of paper: Examination paper, 15 hpDate: May 22, 2012Background: Rheumatoid arthritis (RA) is a chronic remitting polyarthritis that is relapsing.Symptoms are inflammation of the joints with pain, stiffness and degradation of joint tissue.In some cases, also other parts of the body are involved. The treatment consists ofmedications to reduce pain, inflammation and degradation of joint tissue. Today, the offerednutritional treatment is primarily focused on meeting energy requirements and nutrient needs.The diet has also been discussed as symptomatic treatment, and one of the factors believed toinfluence the symptoms is meat.Objective: To assess the evidence as to whether a vegetarian diet affects the symptoms ofrheumatoid arthritis, and if so, to suggest how it can be implemented in practical dieteticswork.Search strategy The databases used in the literature search was PubMed, Scopus, and AMED.The search words used were: "rheumatiod arthritis", "vegetarian", "vegan", "diet", "meat" and"animal protein".Selection criteria: Studies investigating a vegetarian diet on the symptoms of RA wereincluded. Only RCT, clinical trial, controlled clinical trial, human studies and original articlesin English or Swedish were included.
Optimering av sintrade kugghjul
Powder Metal (PM) gears are machine element components which operate under the same principle as conventional gears, but, due to their intrinsic material characteristic need to be designed slightly different, and its manufacturing process offers advantages previously unobtainable by conventional steel gear manufacturing methods. The use of PM in similar applications, such as synchronous hubs, makes them a suitable candidate for production in such material. The current master thesis work focuses on gear design using PM by utilizing finite element method (FEM) to reduce weight and inertia taking into account root bending strength and tooth deflection.First a topological optimization is used to determine feasible candidates for different web designs which have as objective to reduce volume, similar topologies were shown during different loading conditions; and hence, this topology was chosen as a suitable candidate. A shape optimization of the topological candidate was performed having as state variables root bending strength, independent for compressive and tensile side of the tooth loading; and tooth deflection, which in concept can be correlated to static transmission error (TE).Another aspect in this thesis analysed is the possibility to incorporate non-trochoid root geometry, a trochoid root is always present when machining with a hob, into the gear root and hence reduce the stress concentration here. Due to the use of PM, a non-symmetric optimized root can be achieved and hence be optimizing compression and tension.Results showed significantly lower inertia, for example certain results showed 40% reduced when compared to solid gear, with adverse effects as increase in tooth deformation and increase in maximum principal stress.
Utvärdering av akupunktur som behandling vid ryggömhet hos häst : en pilotstudie
Acupuncture has been used for thousands of years in China. Written documents concerning veterinary acupuncture has been found dated around 650 B.C. Acupuncture has gained greater acceptance in the western world the last decades and many countries have established their own veterinary acupuncture organizations.
Many studies report good results after acupuncture treatment and back pain in horses is considered a good indication for acupuncture treatment. In studies published, the results are subjectively evaluated. To get a qualitative, scientific evaluation of acupuncture treatment, objective measurements, control groups and statistical analysis are needed.
This pilot study presents a case where acupuncture has been used for treatment in a horse that was diagnosed with back pain.
Elasticitetsmodulen i en kalkstabiliserad vägterrass : en fältstudie
Stabilization of subgrade is an internationally common technique to improve the characteristics of a soft soil. Improving the stiffness and bearing capacity of the subgrade enables the pavement to be designed with reduced depths of subbase and basecourse aggregates. This makes the stabilization technique both economically and environmentally interesting. Both natural and stabilized soils have high inherent property variability that should be considered when the characteristic value is derived. By analyzing the spatial variability in stabilized and natural subgrades it is possible get the parameters needed for reliability?based modeling of soil properties.
Provning av ythärdade material tänkta för
transmissionsdetaljer
This technical report describes the master thesis in material engineering called ?Testing of surfaced hardened materials conceivable for gears and shafts?. The work extents 20 academic points. Land systems Hägglunds manufactures and sells different kinds of combat vehicles and terrain vehicles. Since the demands for bigger and stronger vehicles increases all the time, so are the demands on shafts, gears and other transmission details.
INVOXICATED. En interaktiv lek med ljud
Invoxicated is an interactive play sculpture where children can explore the wonderful and playful opportunities of sound. Talk into one end of the sculpture, and the sound will travel through the sculpture and come out in the other end. On its way, the sound gets distorted by a number of sound effects. By bending the sculpture?s body, and pressing the sculpture?s buttons, the sound effects gets altered in real time.
Inverkan av tvång i gjutfogar och i betongkonstruktioner på
elastiskt underlag: Influence of Restraint in Casting Joints
and in Concrete Structures on Resilient Foundation
In this report, the risk of cracking in joints and/in adjacent concrete is estimated by checking shear forces in joints and the ratio between the actual maximum principal stress ant the actual strength of the concrete. The shear force has been estimated both by simple methods as well as by two-dimensional calculations. The risk of cracking in the concrete and/or in the joints is estimated with the computer program ConStre. The restraint from a resilient foundation or rock on a young concrete construction is estimated by a simple method that is exemplified. It is shown that the restraint can be neglected in some cases.
Höga hus med deformerbara fundament på pålar : Pålkrafters avvikelse visavi klassisk teori samt förskjutningar beroende av vindlast
When forces in foundation piles are calculated according to classic theory, thefoundation are assumed to be infinitely rigid which means that the foundation will notbend. High buildings need their whole width to be stable and use the ground floorwall as a foundation. But when, for example windows are needed in the ground floorwall, the stiffness of the foundation decreases which change the forces in the piles. Inthis report the difference of pile forces versus classic theory has been analyzed, and ifpile forces can be calculated as in classic theory. Further on, the effects of the wallmovement were analysed and how the buildings crack safety would be affected by themovement at the ground floor.
Specialidrott eller inte? : Kan elever från riksidrottsgymnasiet i karate jämföra sig med svensk karate elit?
SammanfattningInledning: Specialidrott har funnits i skolvärlden sedan 70-talet och har lett till att många ungdomar har kunnat kombinera skola och elitidrottssatsning vid sidan om varandra. Det har skapats RIG (riksidrottsgymnasier) och ämnet specialidrott har lagts till som en kurs på gymnasieskolan. Målet med RIG var att göra det möjligt för talangfulla ungdomar att kombinera elitidrott med gymnasiestudier då gymnasietiden anses vara en brytpunkt för när elitsatsningen börjar. Att gå på ett RIG innebär även att få träna väldigt mycket och tävla med många av de bästa i samma åldersgrupper. RIG-systemet har producerat många svenska elitidrottare i olika idrotter.
Analys av instyrning och rolldynamik
When driving hard and cornering on a circuit good control of a car?s roll is desired, so the car reaches steady state quickly but yet in a controlled fashion. This control is mainly given by the combination of the cars springs, shock absorbers and anti-roll bars.The aim of this report is to investigate, analyze and measure a Porsche Boxster?s turn in behaviour and roll dynamics as well as with the aid of simulation results give suggestions for improvement of the previous mentioned combination.Two different simulations were made, one based on a simpler model that was based on an evolved version of the bicycle model in Matlab and one was more advanced model in the simulation software rFactor. Measurements of the real car was made using a GPS-based measurement system.
Standardisering av snöröjningsplan : Instruktioner, råd och tips för snöröjning av tak med stora spännvidder
The Swedish winters 2009/10 and 2010/11 were rich in snow and many roofs collapsed, mainly largespan frames. Investigations were made and the amount of snow was not the primary cause, insteadthere were several other causes. One of these was that in some cases roofs were shoveled in anunfavorable manner which affected the load patterns negatively, so causing the roofs to collapse.Most people lack the knowledge of how shoveling will affect the roof. Had there been an increasedunderstanding regarding shoveling, some roofs could have been prevented from collapsing.Through both qualitative and quantitative research in the form of interviews and calculations thetheoretically best ways to shovel a selection of roof types is presented in the report. The roofstructures covered are 3-compartment, continuous and Gerberspliced metal roof decks.
Testbänk för luftlager
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.
Naturlig haptisk kraftåterkoppling från volymdata
As the volumes are entering the world of computer graphics the pure volume visualisation becomes a more important tool in for example research and medical applications. But the advance in haptics --- force feedback from the computer --- is behind. In volume haptics no equal to the proxy method so popular in surface haptics has yet emerged. Some implementations of volume haptics even use surfaces as intermediate representations so that surface haptics can be used.The intention of this work was to create natural feeling haptic feedback from volumetric density data using pure volume haptics. The haptic algorithm would be implemented in Reachin API for the Reachin Desktop Display, together with other parts to build up a usable volume visualisation environment.To achieve the feeling of stiffness and friction dependent on tissue type, a proxy based method was developed.
Skiktlimning i skolslöjden : ett gestaltande examensarbete om skiktlimning i slöjdundervisningen
Syftet med detta gestaltande arbete är att ta reda på hur skiktlimning fungerar i skolundervisningen och vilka möjligheter som finns för att integrera den mer i skolan. Syftet är också att bidra med kunskap om tekniken till andra lärare. Detta är ett gestaltande examensarbete. Tre olika produkter tillverkades med hjälp av skiktlimning. Processen dokumenterades så att lärare och elever ska kunna använda dem i slöjdundervisningen.