The primary purpose of this research is to investigate the effectiveness of a scaled roller rig for accurately assessing the contact mechanics and dynamics between a profiled steel wheel and rail, as is commonly used in rail vehicles. The established creep models of Kalker and Johnson and Vermeulen are used to establish correction factors, scaling factors, and transformation factors that allow us to relate the results from a scaled rig to those of a tangent track. �Correction factors, which are defined as the ratios of a given quantity (such as creep coefficient) between a roller rig and a track, are derived and used to relate the results between a full-size rig and a full-size track. Scaling factors are derived to relate the same quantities between roller rigs of different scales. Finally, transformation factors are derived by combining scaling factors with correction factors in order to relate the results from a scaled roller rig to a full-size tangent track. Close-end formulae for creep force correction, scaling, and transformation factors are provided in the thesis, along with their full derivation and an explanation of their limitations; these formulae can be used to calculate the correction factors for any wheel-rail geometry and scaling. For Kalker's theory, it is shown that the correction factor for creep coefficients is strictly a function of wheel and rail geometry, primarily the wheel and roller diameter ratio. For Johnson and Vermeulen's theory, the effects of creepage, scale, and load on the creep force correction factor are demonstrated. �It is shown that INRETS' scaling strategy causes the normalized creep curve to be identical for both a full-size and a scaled roller rig. �It is also shown that the creep force correction factors for Johnson and Vermeulen's model increase linearly with creepage, starting with the values predicted by Kalker's theory. �Therefore, Kalker's theory provides a conservative estimate for creep force correction factors. �A case study is presented to demonstrate the creep curves, as well as the correction and transformation factors, for a typical wheel-rail configuration. �Additionally, two studies by other authors that calculate the correction factor for Kalker's creep coefficients for specific wheel-rail geometries are reviewed and show full agreement with the results that are predicted by the formulae derived in this study. �Based on a review of existing and past roller rigs, as well as the findings of this thesis, a number of recommendations are given for the design of a roller rig for the purpose of assessing the wheel-rail contact mechanics. �A scaling strategy (INRETS') is suggested, and equations for power consumption of a roller rig are derived. Recommendations for sensors and actuators necessary for such a rig are also given. Special attention is given to the resolution and accuracy of velocity sensors, which are required to properly measure and plot the creep curves. / Master of Science

Forward slip (FS), the percent difference between the roll velocity and the strip exit velocity, was achieved by altering four variables: reduction, rolling speed, lubricant viscosity, and roll roughness. A two-high laboratory mill was used to roll strips of unalloyed, H-18 temper aluminum. An SEM and a Leitze Orthoplane microscope were used to examine the strip surface. A grainy pattern, which varied with the rolling condition, was observed on the sample surface. The grainy pattern resulted from three effects: grooves imprinted by the rolls, black spots identified as hydropitting (HP), and horseshoe shaped marks which were attributed to FS. These effects were studied and the following conclusions drawn. Higher viscosity, high speed, and rough rolls produced more HP. Increasing reduction produced HP with the viscous lubricant, oil, but less HP with kerosene. No HP was observed at 59 percent reduction but FS marks occurred and were more prevalent with oil than kerosene. The smooth rolls produced more FS marks than the rough rolls. Two postulates were presented to explain the pattern of these effects. First, the FS mark lengths were of the same order of magnitude as one set of theoretically calculated relative slip lengths; indicating that FS was responsible for the marks. Second, the absence of HP and presence of FS marks, in particular cases, indicated that a hydraulic effect was responsible for the FS marks. The FS marks would have been created as localized high pressure lubricant flowed across the surface to equalize the film pressure. / Master of Science

Over the last decade, the semiconductor industry has witnessed a steady increase in its complexity based on improvements in manufacturing processes and equipment. Progress in the technology used is no longer the key to success, however. In fact, the semiconductor technology has reached such a high level of complexity that improvements appear at a slow pace. Moreover, the diffusion of technology among competitors shows that traditional approaches based on technological advances and innovations are not sufficient to remain competitive. A recent crisis in the semiconductor field in the summer 2001 made it even clearer that optimizing the operational control of semiconductor wafer fabrication facilities is a vital key to success. Operating research-oriented studies have been carried out to this end for the last 5 years. None of them, however, suggest a comprehensive model and solution to the operational control problem of a semiconductor manufacturing facility. Two main approaches, namely mathematical programming and dispatching rules, have been explored in the literature so far, either partially or entirely dealing with this problem. Adapting the Shifting Bottleneck (SB) procedure is a third approach that has motivated many studies. Most research focuses on optimizing a certain objective function under idealized conditions and thus does not take into consideration system disruptions such as machine breakdown. While many papers address the adaptations of the SB procedure, the problem of re-scheduling jobs dynamically to take disruptions and local disturbances (machines breakdown, maintenance...) into consideration shows interesting perspectives for research. Dealing with local disturbances in a production environment and analyzing their impact on scheduling policies is a complex issue. It becomes even more complex in the semiconductor industry because of the numerous inherent constraints to take into account. The problem that is addressed in this thesis consists of studying dynamic scheduling in a job-shop environment where local disturbances occur. This research focuses on scheduling a large job shop and developing re-scheduling policies when local disturbances occur. The re-scheduling can be applied to the whole production horizon considered in the instance, or applied to a restricted period T that becomes a decision variable of the problem. The length of the restricted horizon T of re-scheduling can influence significantly the overall results. Its impact on the general performance is studied. Future extensions can be made to include constraints that arise in the semiconductors industry, such as the presence of parallel and batching machines, reentrant flows and the lot dedication problem. The theoretical results developed through this research will be applied to data sets to study their efficiency. We hope this methodology will bring useful insights to dealing effectively with local disturbances in production environments. / Master of Science

The steel industry has been producing flat plates through the process of hot rolling since the late 1600s. Hot rolling uses a series of rolls to progressively thin a strip of steel to a desired thickness. In deforming the strip, the rolling process causes variations in thickness across the width of the strip. These variations are commonly referred to as crown, which is specifically the difference in thickness between the center and edge of a strip. For most applications steel mill clients require flat products, or products with little variation in thickness. Therefore, variations represent wasted material which must be removed before the plate or sheet can be used in consumer products. Controlling the flatness of the metal strip is a high priority for the hot rolling business. The purpose of this work was to develop a 3-D dynamic model of the rolling process to simulate the behaviour of a strip while being rolled and predict its profile. To accomplish this task, much of the rolling process needed to be modeled. The profile of the strip is a product of the deformation of the rolls and frame within a mill stand. Therefore, not only did the geometry of these components need to be modeled, but the material properties and dynamic motion were required as well. The dynamic nature of the process necessitated the modeling of the rotation of the rolls and translation of the strip, aspects of rolling which are not typically simulated. Five models were developed during the project. The purpose of the first two models was to find the stiffnesses of the roll-stack and stand frame. The roll-stack refers to the rolls and their arrangement. The reference mill from which data was provided used a four-high roll-stack with two rolls above the strip and two below. The frame that holds the roll-stack, while massive, stretches when the strip is deformed between the rolls. This stretch changes the position of the rolls affecting the load and deformation of the strip. A lumped-mass model was created to simulate the dynamics of the roll-stack and frame. When the strip enters the gap between the rolls, there is a large impact force which causes the rolls to vibrate. The lumped-mass model was used to determine parameters to bring the system to steady state. The final two models simulated the entire rolling process with rotating rolls and moving strip. The 3-D dynamic rolling model was capable of predicting the strip profile due after exiting the rolls. Two calibrations were used to reduce model error before running a validation. The rolling causes thickness variation across the width of the metal strips; therefore, strips are intentionally rolled thick to meet a minimum thickness. In modern steel mills, specialized control systems are used to adjust parameters as the steel strip passes through each stand of rolls. Varying the parameters allows the thickness and profile of the strip to be controlled. Each stand may have several rolls in different configurations. These rolls are either work rolls, which directly contact the strip, or backup rolls, which contact the work rolls and stiffen the roll-stack. The stand frame holds the rolls and provides a means to position them. The validation results showed that the exit thickness, strip crown, and rolling load were less than 5% different from the values measured in the test data. The calibrated model was then used to derive strip crown sensitivities to gap, entry crown, work roll crown, and bending force. The 3-D dynamic model was able to predict the strip crown accurately when given calibrated information about the system. This model will be a useful tool for exploring the mechanics of hot rolling in ways that were not previously possible. / Master of Science

Studien har genomförts på ett antal stålplåtar från olika kulturhistoriska byggnader. När kulturhistoriskt värdefulla byggnader ska renoveras måste detta göras med så god kunskap som möjligt om byggnadens olika delar och de värden dessa representerar. Det problem som studien har ämnat att lösa har varit en bristande kunskap om historiska stålplåtar. Studien har därför utförts för att bidra med kunskap som kan användas när gamla byggnader ska renoveras.För att uppnå syftet att bidra med kunskap som kan vägleda renovering av kulturhistoriska byggnader har studiens mål varit att undersöka hur de olika plåtarna tillverkats och vilka resultat de processerna har fått.Detta har genomförts genom att utföra en metallografi på samtliga prover för att undersöka deras mikrostrukturer och få en förståelse för materialen. Även en kemisk analys av materialens innehåll har gjorts genom en optisk emissions spektroskopi.De resultat som hämtades från plåtarna visade hur stor skillnad det var mellan olika tillverkningsmetoder och deras konsekvenser. Genom att ha sett den mångfald av egenskaper som fanns bland plåtarna har slutsatserna dragits att det finns ett värde i att respektera de äldre materialen.Genom att vara medveten om att det kan finnas stora skillnader i materialen kan valet av plåt göras på ett bättre sätt. Under studiens gång blev det även uppenbart hur mycket historia som fanns lagrad i de gamla plåtarna som är viktig att ta vara på. / The study has been conducted on a number of steel plates from different buildings of cultural and historical value. When old, cultural buildings are to be renovated, it must be done with as much knowledge as possible about the different parts of the building and the values that they represent. The problem that the study has aimed to solve has been an inadequate level of knowledge in regards to historical steel plates. Because of this, the study has been conducted to contribute with knowledge that could be used when old buildings are to be renovated.To achieve the purpose of contributing knowledge to guide renovations of culturally and historically valuable buildings, the goal of the study has been to analyze how the different plates have been made and what the results of those processes were.This has been carried out by conducting a metallography on all of the samples to analyze their microstructures and to gain an understanding of the materials. A chemical analysis has also been conducted on the contents of the materials by using optical emission spectroscopy.The results showed how big of a difference there was between different manufacturing methods and their consequences. By discovering the diversity of the properties of the plates the conclusion has been drawn that there is value in respecting the values of the older materials.By being conscious of how large the difference is between different types of steel sheets, better decisions can be made during choice of steel sheet, and it is more obvious how much history that is stored within the old plates.

To assess acute performance-related effects of foam rolling, this study investigated the immediate effects of a standard foam rolling protocol on explosive strength of the plantarflexors and alpha motor neuron excitability in the soleus. Explosive strength was measured via vertical jump height (JUMP) and the Reactive Strength Index (RSI) obtained from a single leg drop jump. Alpha motor neuron excitability was measured by H reflex amplitude as H wave to M wave ratio (HM) obtained from the soleus muscle. JUMP and RSI measures were analyzed from nineteen subjects (12 male, 7 female) HM data were analyzed from 15 subjects (9 male, 6 female). Subjects attended one day of practice and instruction for the single leg drop jump and one day for data collection. One leg was randomly assigned to be the test leg (FL) and the other as the control (NL). The reported dominant leg and gender were also recorded for each subject. Subjects performed two single leg drop jumps per leg from a box height of 30 cm and then 10 soleus H reflexes were obtained. The intervention, which followed standard professional guidelines, consisted of 2.5 minutes of foam rolling for the FL and rest for the NL, followed by a 5 minute warm up on a cycle ergometer. The best jump and the average HM ratio were chosen for analysis. For each variable a post/pre ratio was calculated for statistical analysis. A 2x2x2 factor ANOVA with repeated measures on both factors was used for each variable. Analysis revealed no statistically significant differences for any of the variables, either as main effects or any of the interaction effects. Subjects trended towards a slightly larger post-intervention decrease in JUMP and RSI for the FL than the NL but this was not significant. It was concluded that a 2.5 minute intervention of foam rolling had no acute effect on explosive strength of the plantarflexors or alpha motor neuron excitability of the soleus. / text

Efforts to reduce greenhouse gas emissions from today’s increasing number of cars and trucks, are crucial in counteracting global warming. These efforts include the intent to reduce the effects of the resistive forces acting on the vehicle. Rolling resistance is one of these forces. A reduction in rolling resistance would aid in reducing greenhouse gas emissions, while also reducing the driving costs and increasing the driving range per charge for electric vehicles. This PhD research contributes to these efforts by the development of a rolling resistance measurement method on a flat track test equipment that avoids the curvature effects present in the standardised drum test. Another contribution is the development of a rolling resistance model that can describe the relationship between the tyre deformation and the forces acting on the tyre. The model is parametrised by results from the developed measurement method and is simple enough to be included in complete vehicle dynamicssimulations. In this thesis, the effects of different operational conditions, such as inflation pressure, tyre temperature, speed, load, road surface or tyre angles, are investigated and presented. The results from this investigation were used for the development of the measurement method for flat track test equipment. Tyre temperature is an important operating condition influencing rolling resistance and the proposed measurement method can be used to investigate rolling resistance at different tyre temperatures. The results obtained with the proposedmeasurement method, which are comparable to drum measurements performed under the same operating conditions, are used to parameterise the developed rolling resistance model. The model gives a good fit for the relationship between rolling resistance and tyre deformation. The measurement method and the model build a good platform for deeper investigations of rolling resistance and its connection to tyre temperature. / Arbete för att minska utsläppen av växthusgaser från det ökande antalet bilar och lastbilar är en viktig del i att motverka den globala uppvärmningen. Detta kan göras genom att reducera påverkan från de resistiva krafter som påverkar fordonet, med fokus på rullmotståndet. En minskning av fordonens rullmotstånd skulle medverka till att minska växthusgasutsläppen samt bidra till att reducera körkostnaderna och öka räckvidden per laddning för elbilar.Denna licentiatuppsats bidrar till detta genom att skapa en metod för rullmotståndsmätningar på plant underlag, för att kunna undvikakrökningseffekterna i den standardiserade trummätningen. Ett annatbidrag är en rullmotståndsmodell som beskriver växelverkan mellan däckdeformationer och däckkrafter. Modellen parametriseras med resultat från den framtagna mätmetoden och är tillräckligt enkel för att vara användbar i en komplett fordonsdynamiksimulering. I denna uppsats presenteras påverkan av olika driftsvillkor som däcktryck, däcktemperatur, hastighet, last, underlag och kurvatur. Dessa resultat nyttjades i utvecklandet av nämnda mätmetod för rullmotståndsmätningar på plant underlag. Däcktemperatur är ett viktigt driftsförhållande med stor påverkan på rullmotståndet och den föreslagna mätmetoden kan användas för att mäta rullmotstånd vid olika däcktemperaturer. Denna mätmetod användes sedan för att parametrisera indata till den utvecklade rullmotståndsmodellen. Det visade sig att modelldata avviker från uppmätt data för förhållandet mellan hjullast och däckdeformation på grund av modellgeometrin. Men modellen ger en god överenstämmelse för förhållandet mellan däckdeformation och rullmotstånd. Mätmetoden är, tillsammans med den föreslagna modellen, en bra bas för mer genomgående undersökningar av rullmotstånd och dess korrelation med däcktemperatur.

Efforts to reduce greenhouse gas emissions from today’s increasing number of cars and trucks, are crucial in counteracting global warming. These efforts include the intent to reduce the effects of the resistive forces acting on the vehicle. Rolling resistance is one of these forces. A reduction in rolling resistance would aid in reducing greenhouse gas emissions, while also reducing the driving costs and increasing the driving range per charge for electric vehicles. This PhD research contributes to these efforts by the development of a rolling resistance measurement method on a flat track test equipment that avoids the curvature effects present in the standardised drum test. Another contribution is the development of a rolling resistance model that can describe the relationship between the tyre deformation and the forces acting on the tyre. The model is parametrised by results from the developed measurement method and is simple enough to be included in complete vehicle dynamicssimulations. In this thesis, the effects of different operational conditions, such as inflation pressure, tyre temperature, speed, load, road surface or tyre angles, are investigated and presented. The results from this investigation were used for the development of the measurement method for flat track test equipment. Tyre temperature is an important operating condition influencing rolling resistance and the proposed measurement method can be used to investigate rolling resistance at different tyre temperatures. The results obtained with the proposedmeasurement method, which are comparable to drum measurements performed under the same operating conditions, are used to parameterise the developed rolling resistance model. The model gives a good fit for the relationship between rolling resistance and tyre deformation. The measurement method and the model build a good platform for deeper investigations of rolling resistance and its connection to tyre temperature. / Arbete för att minska utsläppen av växthusgaser från det ökande antalet bilar och lastbilar är en viktig del i att motverka den globala uppvärmningen. Detta kan göras genom att reducera påverkan från de resistiva krafter som påverkar fordonet, med fokus på rullmotståndet. En minskning av fordonens rullmotstånd skulle medverka till att minska växthusgasutsläppen samt bidra till att reducera körkostnaderna och öka räckvidden per laddning för elbilar.Denna licentiatuppsats bidrar till detta genom att skapa en metod för rullmotståndsmätningar på plant underlag, för att kunna undvikakrökningseffekterna i den standardiserade trummätningen. Ett annatbidrag är en rullmotståndsmodell som beskriver växelverkan mellan däckdeformationer och däckkrafter. Modellen parametriseras med resultat från den framtagna mätmetoden och är tillräckligt enkel för att vara användbar i en komplett fordonsdynamiksimulering. I denna uppsats presenteras påverkan av olika driftsvillkor som däcktryck, däcktemperatur, hastighet, last, underlag och kurvatur. Dessa resultat nyttjades i utvecklandet av nämnda mätmetod för rullmotståndsmätningar på plant underlag. Däcktemperatur är ett viktigt driftsförhållande med stor påverkan på rullmotståndet och den föreslagna mätmetoden kan användas för att mäta rullmotstånd vid olika däcktemperaturer. Denna mätmetod användes sedan för att parametrisera indata till den utvecklade rullmotståndsmodellen. Det visade sig att modelldata avviker från uppmätt data för förhållandet mellan hjullast och däckdeformation på grund av modellgeometrin. Men modellen ger en god överenstämmelse för förhållandet mellan däckdeformation och rullmotstånd. Mätmetoden är, tillsammans med den föreslagna modellen, en bra bas för mer genomgående undersökningar av rullmotstånd och dess korrelation med däcktemperatur.

Förmågan att kunna anpassa sig efter rådande omständigheter har aldrig varit mer påtagligt än idag. När Coronapandemin lamslog hela världen 2020 var det mycket i det vardagliga livet som förändrades. Det gick inte att gå ut och äta, träffa sina nära och kära eller planera nästa semester på samma sätt som tidigare. Men det va inte bara enskilda individer som drabbades, många företag fick stänga igen och gick i konkurs. Majoriteten av företagen idag använder sig ett traditionellt sätt för att budgetera och planera för framtiden, man gör budgetar för kommande period och förhåller sig sedan till dessa. Detta sätt att planera och budgetera lyfts fram som kostsamt, tidskrävande och att det försvårar möjligheterna att anpassa sig efter ändrade omständigheter. Men på senare tid har ett alternativ planerings- och budgeteringssätt vuxit fram. Beyond Budgeting är ett alternativ till det traditionella sättet och innebär att man avskaffar dessa traditionella budgetar och använder sig istället av rullande prognoser, benchmarking och balanced scorecard för att bara nämna några styrmedel. Förespråkarna för Beyond Budgeting menar att detta nya sätt att planera och budgetera skulle eliminera de negativa delar som de traditionella metoderna för med sig och att det skulle leda till ökad lönsamhet. Syftet med denna studie är att undersöka hur företag på OMXS30 Nasdaq Stockholm som använder Beyond Budgeting och företag som inte använder Beyond Budgeting skiljer sig åt i lönsamhet, genom att undersöka fem nyckeltal. Nyckeltalen som undersöks är vinstmarginal, likviditet, soliditet, kapitalomsättningshastighet och räntabilitet på totalt kapital. I denna studie har en kvantitativ metod tillämpats där sekundärdata i form av årsredovisningar för åren 2017, 2018 och 2019 hämtats för företagen listade på OMXS30 Nasdaq Stockholm. Nyckeltalen vinstmarginal, likviditet, soliditet, kapitalomsättningshastighet och räntabilitet på totalt kapital har sedan valts ut som representativt för lönsamhet. Resultatet för denna studien påvisar att det inte finns någon statistiskt signifikant skillnad i lönsamhet mellan de företag som använder Beyond Budgeting och de företag som inte använder Beyond Budgeting. Studien visar således att det inte finns något samband mellan Beyond Budgeting och lönsamhet. / The ability to adapt to prevailing circumstances has never been more evident than today. When the Corona Pandemic paralyzed the whole world in 2020, much of everyday life changed. It was no longer possible to go out to eat, meet loved ones or plan the next vacation in the same way as before. But it was not just individuals who were affected, many companies had to close and went bankrupt. The majority of companies today use a traditional way of budgeting and planning for the future, they make budgets for the up coming period and then relate to these. This way of planning and budget is often highlighted as costly, time consuming and that it makes it more difficult to adapt to changing circumstances. But recently, an alternative planning and budgeting method has emerged. Beyond Budgeting is an alternative to the traditional way and means that you abolish these traditional budgets and instead use rolling forecasts, benchmarking and balanced scorecard to name just a few instruments. Proponents of Beyond Budgeting believe that this new way of planning and budgeting would eliminate the negative elements that traditional methods bring with them and that it would lead to increased profitability. The purpose of this study is to investigate how companies on OMXS30 Nasdaq Stockholm that use Beyond Budgeting and companies that do not use Beyond Budgeting differ in profitability, by examining five key figures. The key figures examined are profit margin, liquidity, equity / assets ratio, capital turnover rate and return on total capital. In this study, a quantitative method has been applied where secondary data in the form of annual reports for the years 2017, 2018 and 2019 have been retrieved for the companies listed on the OMXS30 Nasdaq Stockholm. The key ratios of profit margin, liquidity, equity ratio, capital turnover rate and return on total capital have then been selected as representative of profitability. The results of this study show that there is no statistically significant difference in profitability between the companies that use Beyond Budgeting and the companies that do not use Beyond Budgeting. The study thus shows that there is no connection between Beyond Budgeting and profitability.

This thesis presents elliptical rolling contact joints as an alternative to circular rolling contact and conventional revolute joints where high quality force transmission "low friction and backlash" with variable output are desired. Parameters specific to the joint and its position are developed in terms of relative link angles and elliptical surface geometry. These parameters are used to generate the basic forward kinematics for elliptical rolling link toggle mechanisms with oscillatory motion and high mechanical advantage. As large compressive loads are characteristic of such mechanisms, stress conditions are identified and principles for joint stability with variable, precision outputs are discussed. Finally, application is made to self-adjusting passive force closures with a case study of the MUSCLE Brake (Multi-toggle Self-adjusting Connecting-Linked Electromechanical) disc brake caliper. Elliptical rolling contact joints are shown to offer several benefits over circular rolling contact, including: reduced Hertz contact stresses and flexure bending stresses, variable output velocity, maximum use of contact interface by distributing small rotations across surfaces of small curvature, reduced forces on stabilizing members, increased mechanical advantage due to eccentricity, and no-slip pure rolling provided exclusively by connecting links (or flexures) without the need for gear teeth or friction.