The aim of this thesis is to increase the understanding of wear in rolling/sliding contacts such as the wheel-rail contact for railroads and the roller-washer contact for roller bearings. The Stockholm commuter train network has been the subject of papers A and B in this thesis in which the wear and surface cracks on rails has been observed for a period of three years. By comparing the wear depth with the crack length, equilibrium between these two damage mechanisms was found for a lubricated rail. By using a lubricant with friction modifiers the stresses was low enough to prevent crack propagation; at the same time, the rail was hard enough to reduce the wear rate. This is probably the most favourable state in terms of rail maintenance cost. Roller bearings subjected to lubricant borne particles have been the subject of papers C, D and E in this thesis. Particles in the lubricating oil can have a significant impact on the wear in lubricated contacts. Even at low concentration levels can self-generated particles cause significant wear. The here presented results shows that filtration during run-in can significantly reduce both the mass loss and the number of self generated particles. A series of experiments has been carried out to study the wear of roller bearings by ingested lubricant borne hard particles. The form of the worn profile and the length of wear scratches correspond closely to the sliding within the contact. A count of the number of wear scratches on the rolling element surface indicates that the contact concentrates particles. A novel wear model based on the observation of a single point on the contacting surface when a concentration of particles passes through it has been developed and the necessary data for the model has been determined from the experiments. Comparison of the simulation results with the experimental results shows good qualitative agreement for the form change of the washer surfaces. / QC 20101015

Polymeric and particulate organic carbon (POM) are fundamental compounds in the global cycling of carbon, and constitute significant amounts of BOD in municipal wastewater. The main objective of this work is to study molecular size effects on degradation dynamics in biofilm systems. Specifically, the effect of substrate molecular weight on degradation kinetics and transport dynamics, location of depolymerisation enzyme activity and depolymerisation intermediate formation dynamics are assessed. A mathematical model for biofilm degradation dynamics is presented, and used for data interpretation and simulations. Dextran, an -1,6 Glucan, was used as model substrate during batch degradation in a Rototorque biofilm reactor, in addition to batch tests on biofilm sub samples retrieved from the Rototorque, and during pure endo- and exo-Dextranase studies. Oxygen utilisation rate (OUR) estimates and bulk phase TOC mass balances were used to evaluate the effect of variable initial molecular weight on the observed half order removal coefficient (Harremoës, 1978; Rittmann and McCarty, 1980). Size exclusion-HPLC analysis for determination of bulk phase depolymerisation intermediates, and specific enzyme assays were used to evaluate transport dynamics of polymers and location of enzyme activity in the enhanced mixed population biofilm system. Dextran removal rate decrease with increasing Dextran molecular weight. The observed areal half order removal rate coefficient, k1/2,A, demonstrate an approximate 10-fold decrease in the 1-500 kDa range, showing negative logarithmic correlation to the initial MW of Dextran. A less distinct correlation is observed above this transition limit (1-10 MDa). Evaluation of the Thiele moduli, from one step depolymerisation modelling, suggests that the logarithmic reduction in observed removal rate is caused by combined reaction rate and transport limitations. Transport limitations dominates as the polymeric substrate size increase and hinders biofilm matrix diffusion, and the removal rate becomes a surface limited process. Removal of Dextran is biomass dependent in what appears to be a non-linear dependency on biofilm thickness. Expressed as biomass areal density (g/m2), no depolymerisation is observed for thin biofilms (0.7 g/m2), slow for medium (3.7 g/m2) and high for thicker biofilms (5.2 g/m2). Depolymerisation intermediates accumulated in the bulk phase over the entire Dextran size range during pure Dexranase studies, with even size distributions. Final products were oligo-isomaltoses (DP 2-6). Dextran was not depolymerised by -Glucosidase nor Oligo-1,6 Glucosidase. During biofilm reactor and slide sub-sample tests, low MW Dextran intermediates (1-10 kDa) accumulated in the bulk during depolymerisation of 160 kDa Dextran at 250 and 200 mg/l initial concentrations, but were not detected during experiments with 100 mg/l initial concentrations. Intermediate range Dextran (10-100 kDa) did not accumulate in either case. At the same conditions, some assimilable range Dextran (0.2-0.9 kDa) accumulated in the bulk liquid during initial 250 and 200 mg/l batches, but was not detected during 100 mg/l initial Dextran concentrations. The extent of bulk phase accumulation seems to depend on the biofilm growth rate, where more bulk phase accumulation is observed during experiments with starved compared to more actively growing biofilms. More intermediates accumulate during low MW initial standards, compared to higher. These observations indicate that the extent of bulk phase intermediate accumulation is balanced by the rate of depolymerisation, and the substrate uptake rate (growth). Accumulation of intermediate hydrolysis products in biofilm systems is therefore dependent on the slowly biodegradable organic (SBCOD) loading rate. Dextranase was detected in the cellular fraction of the biofilms. The enzyme activity was not detected in any other biofilm sub compartments, implying that the exogenous enzyme remains attached to the cells while working on polymers. These findings support the conceptual model of Confer and Logan (1998), implying that bulk phase intermediate accumulation observed in this study and by others, is not a result of enzymatic activity in the bulk phase, but transport of intermediates from the biofilm matrix.

The purpose with a TPM is to ease the workload for both the maintenance organization and the airline. Until today Norwegian has had problems caused by absence of clear directives how the administrative work between the maintenance organization and the airline should go on. Norwegian wants a manual where issues about responsibility distribution, working procedures and the way of business are clearly illustrated and described. In this project we have focused on a couple of chosen procedures as “Technical Log Procedure”, “Work Order Procedure” and “Spare Part Procedure”. We have tried to create an easy-lucid and user-friendly manual as a result of flowcharts and declaring pictures. The work has been performed in Norwegian´s head office at Stockholm Arlanda Airport.

Idenna uppsats granskades de fem populäraste sociala nätverksspelen på den sociala nätverkstjänsten Facebook. Syftet var att genom att studera speldesignsmönster urskiljaeventuella skillnader mellan sociala nätverksspel och andra digitala spel. Dessa skillnader analyserades för att kontrollera om de kunde vara bidragande faktorer till sociala nätverksspels popularitet. Avslutningsvis skapades och lanserades två spelprototyper där den ena utrustades med några av de spelmönster som uppmärksammats i undersökningen, medan den andra spelprototypen helt saknade dessa spelmönster. De båda spelprototyperna lanserades samtidigt på den sociala nätverkstjänsten Facebook.

En körsimulator är en modellkonstruktion som ska efterlikna ett verkligt fordon. Den körsimulator som finns vid Statens väg- och transportforskningsinstitut, VTI, bygger på en riktig fordonskaross och ett avancerat rörelsesystem. Omgivningen simuleras och visas för föraren på tre skärmar. I dagsläget finns ingen modell för generering och simulering av trafik till VTIs körsimulator. Syftet med detta examensarbete var att ta fram en sådan modell. En del av examensarbetet var att undersöka förekomsten av modeller för generering och simulering av trafik till körsimulatorer i världen. Resultatet av undersökningen är att det åtminstone finns tio sådana modeller. Den modell som konstruerats för att generera och simulera trafik är giltig för en rak, torr och plan fyrfältig motorväg utan på- och avfarter. Den konstruerade modellen har döpts till Intelligent Traffic Generator, INTRAG. Modellen för att generera trafiken bygger på tre olika typer av områden. De tre typerna är: simulerat område, kandidatområde samt genereringsområde. I det simulerade området, området närmast simulatorn, simuleras fordonen enligt detaljerade modeller för förar- och fordonsbeteenden. De förar- och fordonsmodeller som används i modellen för car-following, körfältsbyten samt acceleration bygger till stor del på modellen Traffic Performance on Major Arterials, TPMA, och VTIs trafiksimuleringsmodell. Det finns även modeller för retardation, transformation av ideal hastighet samt hur förare kommunicerar med körriktningsvisare och bromsljus. Kandidatområdena är de områden som omger det simulerade området. De fungerar som en buffert av fordon. I dessa områden uppdateras fordonen sällan och inte enligt några modeller för förar- och fordonsbeteenden. Det finns två genereringsområden, ett i slutet av respektive kandidatområde. I dessa områden genereras nya fordon. Förutom att konstruera en modell för att generera och simulera trafik till en körsimulator bestod uppgiften i att ta fram ett upplägg för hur kommunikationen mellan modellen och körsimulatorn ska se ut. Kommunikationen i det framtagna upplägget sker över intranät med internetprotokollet IP och transportprotokollet UDP. De paket som skickas mellan modellen och körsimulatornpaketeras efter en framtagen struktur. Modellen har implementerats i programmeringsmiljön Borland Delphi 5. För att kunna testköra modellen skapades en applikation som fungerar som ett substitut för en körsimulator. Substitutet har även använts vid verifiering och validering av modellen. Vid verifieringen framkom att det uppmätta flödet i modellen i medel ligger mellan 3,6 och 9,9 % för lågt. Detta beror troligen på dåliga mätmetoder. För övrigt verkar modellen vara korrekt implementerad. Modellen har inte kunnat testköras mot VTIs körsimulator. De testkörningar som genomförts med körsimulatorsubstitutet har dock givit en indikation på att modellen är en bra avbildning av verkligheten. / ISRN/Report code: LiU-TEK-LIC- 2005:58

Turning solar collectors, heliostats, is certainly not a new idea but has been explored for at least two decades. Projects on this subject have resulted in more or less realistic constructions, in a commercial point of view. Far too often the technical goals have had higher priority than the economical, which has resulted in a few constructions having the ability to compete with conventional, fix solar collectors. The economical issues have been given high priority in this project, without decreasing the demands on reliability. The system has been given the following mechanical and electronical properties: One-axis movement, fix heat carrying fluid system, microcomputer controlled movement and automatic protection from overheating. According to the development in digital technology with lower prices on advanced semiconductors as a consequence, the conclusion is that the prerequisites of this concept will be even better in the future. The result of this thesis is a heliostat function that increases the energy gain by up to 40%, compared to a field of MaReCo collectors without this function. Though, the cost only increases by 13%.

This master's thesis develops an algorithm for tracking of cars robust enough to handle turning cars. It is implemented in the image processing environment Image Processing Application Programming Interface (IPAPI) for use with the WITAS project. Firstly, algorithms, comparable with one currently used in the WITAS-project, are studied. The focus is on how rotation, that originates from the turning of the cars, affects tracking performance. The algorithms studied all perform an exhaustive search over a region, close to the last known position of the object being tracked, to find a match. After this, an iterative algorithm, based on the idea that a car can only rotate, translate and change scale, is introduced. The algorithm estimates the parameters describing this rotation, translation, and change of scale, iteratively. The iterative process needs a initial parameter estimate that is accurate enough for the algorithm to converge. The developed algorithm is based on an earlier publication on the subject, however the mathematical description, and deduction, of it is taken one step further than in this publication. The iterative algorithm used performs well under the assumption that the data used fulfills some basic criteria. These demands comprises: placement of camera, template size as well as how the parameters may vary between two observations. The iterative algorithm is also potentially faster than exhaustive search methods, because few iterations are needed when the parameters change slowly. Better initial parameters should improve stability and speed of convergation. Other suggestions that could give better performance is discussed, e.g., methods to better extract the target from the surroundings.

Det finns inte mycket information dokumenterad om fotgängares interaktion med fordon vid övergångställen och det är denna interaktion vi studerat inom detta examensarbete. Arbetet har varit en studie av befintlig litteratur på området, genomförandet av en fältmätning och en analys av denna fältmätning. Det finns många olika faktorer som påverkar en fotgängare då han korsar en gata. Syftet med examensarbetet var att hitta dessa faktorer och sambanden mellan dem samt redovisa allt i en modell. Examensarbetet avgränsades till att enbart ta hänsyn till fysiska faktorer. Den faktor vi främst fokuserade på var tidsluckan till ett fordon som en fotgängare accepterar för att kunna korsa gatan, främst genom att det var den dominerade faktorn i litteraturen. Fältmätningar genomfördes för att samla in data för analys och mäta de viktigaste faktorerna. Sammanlagt genomfördes tre fältmätningar, ett signalreglerat i Stockholm och två obevakade övergångsställen i Linköping. Antalet intressanta mätfall var begränsat vid samtliga mätplatser och därför har vi inte kunnat se alla de samband av faktorer som vi förväntade oss. Den största skillnaden mellan signalreglerat och obevakat övergångsställe var väntetiden. En mätplats gav tillräckliga värden till den accepterade tidsluckan för att beräkna en regressionsmodell. Kritisk tidslucka för en fotgängare påverkas främst av om denne korsar gatan ensam eller i grupp och av fotgängarens gånghastighet. Faktorerna ålder och kön, vilka starkt förväntades påverka den accepterade tidsluckan, visade sig ha väldigt lite påverkan. Med kritisk tidslucka menas den gräns över vilken fotgängaren normalt accepterar en förekommande tidslucka i fordonsflödet. När trafiken är tät och tidsluckan tenderar att minska så påverkar det fotgängaren så att den accepterade tidsluckan minskar. Fotgängare som accepterar extremt korta tidsluckor under 5 sekunder gör detta endast om fordonshastigheten är lägre än genomsnittet.

Servera R&S AB is Sweden’s largest wholesale company within the restaurant and food service industry. Servera R&S AB is the daughter company to Axel Johnson AB, which in turn is a part of the Axel Johnson Group with Antonia Ax:son Johnson as the owner. Servera is a nation wide company with a business concept of offering a complete selection of merchandise and services to the professional food service market. The company is split into for different regions: the north region, the middle region, the southwest region, and the southeast region and has its headquarter in Stockholm. In every region there is a regional office and warehouse. The southeast region includes Blekinge, Småland, Öland, Gotland, Östergötland and Stockholm including Södertälje. The regional warehouse as well as the sales office for this region is located in Norrköping. Servera is heavily dependent on road transportations. There are approximately 38 deliveries leaving the regional warehouse in Norrköping on a daily basis. These are either delivered directly to the customer or to distribution points in the region. These factors create a high importance when the routes are planed out. The deliveries today are on fixed routes and the work to coordinate the deliveries is done by the delivery supervisor. The planning of the routes is always done one day in advance, meaning that the deliveries planed out today will be sent out tomorrow. The issue evolving by this is the delivery supervisor estimating the number of trucks that will be needed the following day. The only tool the supervisor has to use for this is Servera’s internal database system called Servo. Servo is a complete ASW-system, modified to serve Servera’s wholesale of provisions. Servo contains information about customers, incoming deliveries, stock, deliveries, purchases, sales, etc. The southeast region plans to introduce a new routing system to its operation. Today’s route planning is somewhat inefficient and non-flexible. The goal is to increase the efficiency and lower the logistic cost, but at the same time maintain the current service for the customers. The routingprogram in mind is Roadshow 1.5, which is owned and developed by Canadian based Descartes System Group Inc. located in Waterloo. Roadshow 1.5 is a dynamic route planning system developed to ease the work of planning deliveries. Roadshow lets the user create, edit, update, and simulate routes based on conditions in the operation. At every simulation, Roadshow will consider the cost factors that have been preprogrammed and will calculate and propose the most cost efficient route for the deliveries. The purpose of this project was to get a better understanding of how an introduction of the route planning system, Roadshow 1.5, will affect the southeast region operations with regards to cost, routine, flow as well as the administration in general. In order to achieve this, two scenarios were simulated in Roadshow. In the first scenario, the fixed routes were kept but they were reorganized in order to try to cut back cost. In the second scenario Roadshow was allowed to completely create new routes based on the conditions for Servera. The results were then reviewed and analyzed resulting in an answer to if Roadshow is a profitable investment for the southeast region of Servera.

The aim of this report is to analyse the logistics of a medium sized restaurant and give an overall solution for improvements on the restaurant's logistics. The restaurant of interest belongs to Laponia Hotel and is located in Arvidsjaur, Sweden. Investments for over 100.000 Euros are planned for the hotel, which includes a reconstruction of the restaurant. The details on how the restaurant will be reconstructed are not yet known. I therefore chose to analyse the problemin general terms and find a solution that is focused on the logistic system itself rather than its layout. In order to find the best system I have chosen to analyse three different logistic models, each representing different levels of logistic systems. The first model, representing the logistics of a small restaurant, is named ´the simple logistic model´ and has a manual system. The second method is called ´the complex logistic model´. This model describes the hotel that is too small to afford a full-scale computer system, and too complex to operate with only a manual system. The last model is'the advanced logistic model'and it is meant to represent the full-scale logistics with all necessary computer aid. The models are analysed by the SWOT method and the materials used are found through literature research, interviews and observations. The analyse shows that the best model for Laponia Hotel's restaurant would be the advanced logistic model in combination with the simple logistic model. This would allow the restaurant to use all the benefits of computer aid and large quantities without loosing the small-scale feeling of ownership and responsibility among the employees.