The dynamics of fluid flow unveils complicated dynamical behaviour. Systems such as a dripping tap are no exception. Flow through a nozzle produces three different modes: periodic dripping, chaotic dripping and jetting streams. This research concentrates on a study of the chaotic behaviour of a dripping tap. This involves both mathematical model studies and experimental studies. In addition, the work involves the development of an experimental facility to allow future study of the system in microgravity conditions. The facility to achieve microgravity conditions is a Drop Tower type, which uses a novel approach to achieve these conditions. The novelty is in the use of linear electromagnetic motors. The facility was built and is in the final stage of the commissioning process, and when it is ready it will allow up to 2.12 s of test time. The mathematical model uses an existing Mass-Spring-Damper model, with Reynolds numbers between 4 to 175, and a step size of 0.4. The results showed multiple bifurcation regions appearing before chaotic regions. Similarly, experimental results showed that some instabilities exist in this region. The model also explained and showed multiple bifurcations and an increase in dripping time due to instabilities, and has identified that those processes are due either to perturbations of the system or due to initial instabilities of the system. These results were confirmed by experiment. To achieve the required experimental goals a test module was developed whose requirements were set to fulfil the microgravity experiment conditions, in case future research is required. The experimental results showed some similarities with the mathematical model. At the same time, there was found to be quite a lot of disagreement. Results identified two different limit cycle attractors in periodic dripping mode: strong single-point attractors and regional attractors. Also, limit cycle attractors and strange attractors in chaotic mode were identified. More importantly, it has been identified that the chaotic region consists of areas where the system is stable (and produces a single region attractor), and others where the system is not (and this produces strange attractors), and there are points where, depending on the disturbances to the system, both types can be observed. The work done has led to several discoveries and achievements. Although the Drop Tower project could not be completed it may nonetheless be considered as a success. The facility has been fully assembled and calibrated to meet the set of design requirements, and to some extent was commissioned allowing future progress to discover modification requirements. The study of the Mass-Spring-Damper model led to the conclusion that the model is oversimplified and in its current state should be used only for descriptive purposes, when illustrating chaotic behaviour. Additionally, it was found that the model predicts bifurcations outside the experimentally determined chaotic region. Nevertheless, the work identified some possible improvements to the model. Experimentally it was found that the region of chaotic behaviour is located around a Reynolds number of 43 in contrast to what was previously reported. The study of the periodic dripping region showed that the system, if disturbed, can develop history dependent phenomena (where the subsequent drop periods follow a well identified sequence). Satellite drops were discovered to exist beyond the previously predicted value of flow rate. It was discovered that the fluid supply system can have a major effect on the drop dynamics (different types of post-detachment developments were found - termed here regular residual mass and wetted mass - along with the discovery of different types of drop detachment (regular mass, mid-size drops and jets) coexisting within the chaotic region. The drop horizontal disturbance study led to the unconfirmed discovery of two modes of vibrations, where the system response follows a standard damped response and an amplitude modulated damped response.

In order to meet increasingly strict regulations on vehicle emissions, manufacturers are seeking ways to produce vehicles that emit less pollution and consume less fuel. Eco-driving is the optimisation of velocity and gear selection in existing vehicles to reduce fuel consumption and such reductions can be made at relatively low development costs compared to powertrain modification. However, the driving experience of a premium vehicle could be compromised if the vehicle behaviour differs from that which is expected by the driver and the acceptance of such fuel saving measures may be diminished. Therefore, in order to maintain the driving experience the contribution of this work is the development and implementation of an optimal control algorithm based on Dynamic Programming which optimises, in real time, the vehicle velocity and gear selection based on a vehicle and upcoming road model while consideration is given to objective measures of driveability. The algorithm is deployed on a Raspberry Pi miniature computer with connection to the vehicle data network. Fuel savings and time savings are identified with the optimisation algorithm both with and without violating constraints on driveability, first in simulation and finally in a real-time, in-vehicle eco-driving feedback system. Primarily the application of this system is in internal combustion engine passenger vehicles in both urban and extra-urban road situations, however the approach is deliberately flexible to allow development for other powertrain configurations.

<p>Examensarbetets uppdrag är att skapa en bild av dagens situation gällande duglighet vid de två bearbetande verkstäderna TMA och TMG. Vidare ska en analys av duglighetsarbete i dagsläget utföras och en modell för hur arbetet kan ske i framtiden tas fram.</p><p>Syftet med examensarbetet är att erbjuda berörd personal vid Volvo Construction Equipment AB Component Division i Eskilstuna en modell för arbete med duglighetsstudier och uppföljning så att dugligare processer kan uppnås. Det primära syftet är att skapa rutiner så att man fortsätter arbetet efter ett duglighetsindex beräknats och inte endast konstaterar att resultatet är bra eller dåligt. I efterarbetet ska man försöka koppla bidragande faktorer från ett otillfredsställande utfall till de 4M:en (Maskin, Människa, Metod och Material).</p><p>På CMP sker självklart ett kontinuerligt kvalitetsarbete då ett av Volvos starka kärnvärden är kvalitet, men trots det ständiga arbetet når man inte alltid de uppsatta kvalitetsmålen. Ett steg i att förändra situationen är införandet av ”The CMP Zero Tolerance Program” som är ett led till att förbättra kvaliteten och sänka antalet defekter till 600 PPM. Detta examensarbete är en del i det programmet och fokuserar på duglighetsarbetet.</p><p>För att nå dugligare processer krävs ett kontinuerligt förbättringsarbete. Det förutsätter att man aktivt fortsätter projektet efter att man beräknat ett duglighetsindex samt lokaliserar orsakande faktorer och förbättrar läget. För att få till detta arbete krävs rutiner och engagemang. Rapporten levererar en modell för hur man vardagligt kan arbeta med duglighet men även rutiner för en effektivt förbättringsarbete.</p>

No description available.

<p>In order to accomplish that a construction is correctly built, it is critical to obtain a well functioning control mechanism throughout the project. The way to enable this is not by having an independent inspector constantly at your side. Today it is praxis to use check lists and have people responsible of quality to make sure that these are followed. This is where discretionary inspections play their part. These among others are documents needed to com-plete the check list. Documented discretionary inspections are based on a control mechanism that allows the entrepreneurs to, in their own organizations, self check the performed task, and by that ensure that the quality of each task is executed in a satisfying way. Due to the fact that most projects today are suffering by lack of time during construction, it is most likely to presume that the discretionary inspections can fall out of the priority, be performed in an unsatisfying way or not be performed at all.</p><p>However, experience from construction business tells us that calculated energy consumption often differs from the actual, once the building is completed. This anomaly strikes hardest to apartment blocks and therefore we intend to find a connection between poorly executed dis-cretionary inspections and high energy usage. Discretionary inspections are used by most contractors in the construction business to ensure that the work in progress always serves en-vironmental lines of thoughts.</p><p>During the progress in our writing we have achieved a good insight in routines and how the business works, for good and for bad. The report finishes with a discussion considering the overall concept of discretionary inspections, how to improve them and potential ways of supporting the concept in the future.</p>

No description available.

<p>Abstract</p><p>My task was to prepare the already designed heating list “Stayhot” for manufacturing.</p><p>I started with drawing the whole list in the CAD-program. It became obvious that some of the designed components had to be changed to work in practice.</p><p>A turnable reflector couldn’t be combined with the isolation. The suggested light emitting diodes wouldn’t give enough light, so I cut them out and the problem with light remains to be solved. The old grating had many rods and I changed that to a grating with fewer rods to make it easier to clean. The hanging-up of the grating was also changed.</p><p>The lower ceasing was changed to be closed towards the reflector to avoid filth and damp.</p><p>The reflector had a different shape. From having been square it became oval to follow the shape of the above ceasing and have a more even isolation. It also opens up to the possibility to use two heating elements. The heating-source should have been changed to be warmer, but as the new elements didn’t come until my work was almost finished, I couldn’t use it.</p>

<p>Bakgrunden till examensarbetet är att det finns ett behov av att höja utnyttjandegraden i stans- och lasermaskiner hos Lars Höglund AB. Anledningen till att utnyttjandegraden behöver höjas är att företaget vill bli mera lönsamt och mera konkurrenskraftigt.</p><p>Uppgiften har varit att mäta utnyttjandegraden, göra en probleminventering och ta fram förslag på åtgärder som kan lösa de problem som kom fram i probleminventeringen.</p><p>Vid probleminventeringen visade det sig att det går att höja utnyttjandegraden genom att bl.a. göra en ställtidsreducering, skapa ordning och reda, samt att förebygga flaskhalsar.</p><p>5S är en metod som har använts för att ta fram förbättringsåtgärderna. Genom att följa denna metod, samt att göra några nya investeringar i företaget, ser det ut som att målet i detta arbete ska kunna uppnås.</p>

<p> </p><p>På ABB i Ludvika tillverkar man en mängd produkter för högspänningsanläggningar. En av dessa produkter är ventilavledare. Ventilavledaren är en säkerhetsapparat som ska skydda övrig utrustning mot förekommande överspänningar. Ventilavledarna som tillverkas i Ludvika är gjorda för system från 52kV upp till 800kV, vilket är den högsta spänningen som används i världen idag. Idag finns två varianter av ventilavledare en med porslinisolant och en med polymerisolant. På ABB ser man att kunderna mer och mer eftersträvar polymeravledare.</p><p>Polymeravledare har p.g.a. mekaniska begränsningar inte kunnat användas i system med högre spänning än ca. 245kV. För att kunna erbjuda polymeravledare för högre spänningar har en ny produkt tagits fram. Den nya produkten kallas <em>PEXLIM Stark. </em></p><p>Med den nya produkten innebär en mängd processer som måste arbetas fram. En sådan process är slutmontaget där man monterar de sista detaljerna.</p><p>Detta arbete har gjorts för att se vilka problem som kan uppstå vid slutmontaget och hur man löser dessa på bästa sätt.</p><p> </p><p> </p> / <p> </p><p>ABB has a big factory in Ludvika where many kinds of apparatus for high voltage systems are manufactured. Among the products are surge arresters, which are used to protect other equipments in power systems against all type of transient overvoltages. The arresters manufactured in Ludvika are for voltage systems from around 52kV up to 800kV which is the highest system voltage level in the world so far. The active elements in the arresters are blocks of ZnO material. The arresters are manufactured utilizing two types of enclosures, porcelains and polymer. Due to the good response from the customers more and more arresters are manufactured with polymer housings but so far the mechanical strength has prevented polymer designs for higher voltages than approximately 245kV. In a new project, therefore, a polymer housed arrester with higher mechanical strength will be developed. The working name for the new product is <em>PEXLIM Strong. </em>Among all the problems which have to be solved during the development of the new product is also how the final assembly of the product shall be performed. In this report, as part of a Bachelor of Science in Machine Engineering, the problems are analyzed and different solutions to obtain an efficient final assembly of the new product are suggested.</p><p> </p><p> </p>

<h2>Abstract</h2><p>At the plant of Outokumpu Stainless Tubular Products AB in Molkom a wide range of butt weld fittings are produced. These are aimed mainly for the process industries and one of the products are ninety degree bend elbows in various dimensions. The elbows are made from stainless sheet metal and when formed to a tube they need to be welded along its inner radius. This is made by a pick and place type industrial robot working in a closed compartment. The assignment given by Outokumpu aims to investigate and suggest a new concept for a more reliable manufacturing process within the work cell.</p><p> </p><p>The cell consists of five main areas chronologically listed as passed by the elbow:</p><p>·          Automated, vibrating conveyor.·          Fixture with the purpose to serve the robot with one elbow at a time, placed in the correct position.·          Industrial robot to pick up the elbow and drag it along the welding head.·          TIG inverter with a stationary welding head·          A hydraulic press with a template of the final shape of the elbow corrects flaws. Almost every problem in the cell and defects on the products coming out of it can be traced back to the fixture and in some cases also to the robots pick up tooling. The focus of the task was therefore put mainly on those two areas. As the work proceeded Outokumpu chose to develop a new tool for the robot themselves which they did with good results. I chose to incorporate it into my study and change focus to the fixture instead.</p><p> </p><p>The problems and possible causes to them were identified and discussed with my tutor:</p><ul><li>The elbows fall incorrectly into or beside of the fixture.  <ul><li>Fixtures are old and worn down.</li><li>The elbows path between conveyor and fixture are somewhat out of control</li><li>The smaller dimensions have room enough to slip past the fixture. <ul><li>Edges to be welded are to far from each other or badly shaped</li></ul></li></ul></li><li>Commissioning time, some start up steps is more complex then they need to be. <ul><li>Some of the setting possibilities in the working cell are unnecessary and can be fixed instead.</li><li>The positions of pick up and welding head are not really fixed in the robot software, these are reprogrammed every time elbow size are changed.</li></ul></li></ul><p>·          Various errors at weldingo    Robot managed to pick incorrectly placed elbow</p><p> </p><p>Proposals to solve the above specified problems:</p><ul><li>All parts in contact with the elbows are to be made of harden able steel. A suitable one is C45E which can be casehardened to about 700HV.</li><li>On the outer edge of the conveyer a support are placed to prevent excessive wear.</li><li>The fixture is partially redesigned with a support to control the elbows path better.</li><li>Guide arms with dual purpose are added. First they guide the elbow into the fixture and secondly they turn it to the correct angle towards the robot.</li><li>Pins are used along with quick lock clamps to obtain faster and easier commissioning.</li><li>The pick and place tool developed by Outokumpu are used.</li></ul>