This paper is focused on MR dampers and its critical parts in term of damper`s durability, which seems to be a piston-rod seals, and it should find an ideal material combination of seal and MR fluid for increasing the damper`s life. The tests were conducted in modified pin-on-flat configuration, which was supposed to be more suitable for laboratory testing. There was tested and compared a suitable material for seals, like PTFE, NBR, SBR of polyurethanes. The article is also focused on MR fluids and its contribution to seal`s wear. The impact of particle concentration, wear of MR fluid and effect of modification of MR fluid was tested. It showed up, that the best material for seal is H-PU95FDA. The effect of particle concentration is negligible on seal`s wear, while effect of modification and wear of MR fluids are significantly higher.

The thesis is focused on the cooling cycles, namely cycles of absorption. The work is divided into several parts, as problems to be solved. The first part deals with the principles and using refrigeration cycles in practice, their involvement and by comparing the working pairs of substances circulating in the absorption unit. The practical part deals with making a proposal for one-and two-level modular absorption cycle of 6 kW, and the subsequent techno-economic comparison with commonly supplied absorption unit

Práce se zabývá návrhem jednoúčelového plně automatického zařízení pro automobilový průmysl, které dávkuje silikonovou směs do pouzdra snímače. V první části práce je řešen návrh mechanické části zařízení, zejména manipulátoru pro polohování dávkovací hlavy. K pohonu manipulátoru je využito pneumatických prvků, které jsou řízeny elektrickými signály. Druhá část práce se zabývá řízením stroje, které je realizováno pomocí PLC systému. Obsluha může ovládat zařízení nebo sledovat aktuální stav na dotykovém panelu. V závěru práce je prezentováno skutečné provedení zařízení a propojení s výrobní linkou.

The thesis engage in structure of solar collectors in theoretical part. Secondly, theory of thermal spraying coating and anodizing is subscribed. In practical part of thesis is proposition of producing a spectral selective surface suitable for solar absorbers. Finally the properties of the samples are checked by thermographic camera shots.

This diploma thesis deals with the design of the front landing gear with steering nose leg and hydropneumatic shock absorber, designed for aircraft PS - 28 Cruiser. In the thesis there was created design of basic types of front landing gear and the best option was selected. The work is further elaborated design of hydropneumatic shock absorber and comparise with the measured load. At the end of the work it was created the structural design of the front landing gear.

Detta examensarbete är genomfört på uppdrag av företaget Smellwell AB och ämnar en produktutveckling av deras produkter. Smellwell tillverkar och säljer fuktabsorberande påsar med en fräsch doft för användning i skor och annan träningsutrustning. Målet med detta arbete var att ta fram och applicera en förbrukningsindikator på deras fuktabsorbenter. Det är idag svårt att avgöra när produkten är förbrukad vilket kan leda till att många kunder använder produkten för länge. Detta kan leda till en sämre användarupplevelse. Syftet med arbetet var därför att öka kundvärdet genom att kunna erbjuda kunden ett sätt att alltid veta när det är dags att byta ut sin produkt för maximal effekt.  Problemet delades upp i två delproblem som löstes var för sig. Först togs det fram en lämplig indikator och sedan skapades tre appliceringsmetoder för indikatorn genom en produktutvecklingsprocess. I arbetet med att ta fram appliceringsmetoderna användes två olika 3D-skrivare som hjälpmedel, en Makerbot Replicator+ och en Objet Eden 260v. Arbetet resulterade i en 6-månaders tidsindikator från det engelska företaget Timestrip® UK Ltd och tre olika indikatorhållare för olika appliceringsmetoder på fuktabsorbenten. Resultaten har utvärderats av en fokusgrupp och förslag på kostnad och framtida tillverkningsmetod har angetts. Koncept 2 och koncept 3 fick bäst betyg i utvärderingen och kommer rekommenderas till Smellwell att gå vidare med. / This bachelor thesis has been carried out on behalf of Smellwell AB and aims at product development of their product. Smellwell manufactures and sells moisture absorbing bags with a fresh scent for use in shoes and sports equipment. The aim of this work was to produce and apply a consumption indicator to their moisture absorbers. Today it is difficult to determine when the product is consumed, which can lead to many customers using the product for to long. This can lead to a poorer user experience. The purpose of the work is therefore to increase customer value by offering the customer a way to always know when it is time to replace their product for maximum effect. The problem was divided into two sub-problems that were resolved separately. First, an appropriate indicator was developed and three application methods were created through a product development process. In the process of developing the application methods two different 3D-printers were used, a Makerbot Replicator+ and an Objet Eden 260v. The work resulted in a 6-month’s time indicator from the English company Timestrip® UK Ltd and three different holders for application at different positions on the moisture absorber. The results have been evaluated by a focus group and proposals for cost and future manufacturing methods have been specified Concept 2 and Concept 3 got the best rating in the evaluation and will be recommended to Smellwell to proceed with. / <p>Betyg 181031</p>

This work presents the development of a new pretreatment for clear coated wood, that aims to increase the photoprotection of exterior wood products, and at the same time make the system more environmentally friendly. The pretreatment comprises the reactive UV absorber 2-hydroxy-4(2,3-epoxy­propoxy)-benzophenone (HEPBP), which has a primary epoxy group that can be covalently attached to the hydroxyl groups of the wood substrate. This reactant is accompanied by renewable epoxy functionalized soybean oil (ESBO), which contains a secondary epoxy group that also has the ability to react with the substrate and that promotes the compatibility between the two reactants. The ESBO further seems to have the advantage of increasing the flexibility of the pretreated veneers as well as decreasing the amount of water in the cell wall of the wood. The study was performed in two parts where the first part focused solely on the development and performance of the pretreatment, whereas the second part used the knowledge gained from part one to evaluate the pretreatment in combination with an acrylic clear coating. Grafting reactions were performed on thin wood veneers heated in solvent. In the first part the reaction parameters, temperature and reaction time, were varied to study their effects on the final properties of the pretreatments. The veneers where then analyzed using FTIR to determine if grafting was achieved. Results show that grafting was successful for reactions performed at temperatures above 90 °C. For part two, grafting was successful for both the boil- and dip process, indicating that a considerably shorter reaction time can be used. Samples from both part one and two where then exposed to accelerated ageing and the color change was measured to estimate the UV-resistance. The first part showed improved UV-resistance for some of the pretreatments, whereas the second part was more difficult to evaluate due to the top coat, but a slight improvement can be seen for samples using the pretreatment. A positive result for part two is also that the pretreatment do not appear to affect the adhesion between the substrate and the top coat. It is hence concluded that the proposed pretreatment is a possible way of increasing the photostability of exterior wood. / Detta arbete beskriver utvecklandet av en ny förbehandling för klarlackat trä som syftar till att öka UV-beständigheten av träprodukter för utomhusbruk. Arbetet syftar även till att utveckla systemet till att bli miljövänligare än nuvarande liknande produkter på marknaden. Förbehandlingen utnyttjar primära epoxidgrupper hos den reaktiva UV-absorbenten 2-hydroxy-4(2,3-epoxy­propoxy)-bensofenon (HEPBP) för att skapa kovalenta bindningar till hydroxylgrupper hos träet. Den andra komponenten i systemet är förnyelsebar epoxiderad sojaolja (ESBO) innehållande sekundära epoxidgrupper som även dessa kan binda kovalent till träytan, samt gynna kompatibiliteten mellan de två reaktanterna. Oljan verkar dessutom öka flexibiliteten av förbehandlingen, samtidigt som den minskar mängden vatten som tränger in i cellväggen. Studien utfördes i två delar där den första delen fokuserade enbart på att utveckla förbehandlingen, medan den andra delen utnyttjade information från den första delen för att utvärdera funktionen av förbehandlingen i kombination med en akrylatbaserad klarlack. Ympningsreaktionerna utfördes på tunna träfaner i uppvärmd lösning. I första delen studerades hur temperatur- och reaktionstidsförändringar påverkar den slutgiltiga prestationen av förbehandlingen, och FTIR användes då för att verifiera ympningen. Resultaten visar att ympningen var lyckad för reaktioner utförda vid reaktionstemperaturer över 90 °C. För del två ansågs ympningen lyckad för både dopp- och kokreaktionen, vilket tyder på att betydligt kortare reaktionstider skulle kunna användas. Prover från både del ett och två utsattes sedan för accelererad åldring där färgförändringen av proverna mättes för att uppskatta UV-resistensen av behandlingarna. Första delen visade på ökad UV-beständighet för vissa av behandlingarna. Del två var dock svårare att utvärdera till följd av klarlacken, men en liten förbättring kan noteras för prover som är förbehandlade. En positiv notering från del två är även att adhesionen mellan klarlacken och träytan inte verkar ha påverkats av förbehandlingen. Med detta som grund dras slutsatsen att den föreslagna förbehandlingen kan förbättra UV-resistensen av klarlackat trä för utomhusbruk. / QC 20120330

There is a demand for renewable energy in today’s society. Wave energy is a nearly untapped source of renewable energy. Ocean Harvesting Technologies AB (OHT) is currently developing a device that can be used to convert wave energy into electricity. The device is a Wave Energy Converter of the type point absorber. Their concept is a floating buoy that is connected to the seafloor via a Power Take-Off (PTO) unit. The PTO unit is equipped with generators, which are used to convert kinetic energy of the buoy into electricity. The objective of this thesis is to control the generators to optimize the performance of the system. OHT was interested in knowing how their system performs under the influence of a controller based on MPC. Hence an MPC-controller is constructed in this thesis. The developed controller functions by predicting the states (position and velocity) of the buoy over a finite time (e.g. $5s$). Then the controller uses the predictions to find a control force that makes the system behave optimally for the next $5$ seconds. A requirement from the company is that the controller should find the control force based on how the buoy is predicted to move in 3 Degrees Of Freedom (DOF). Further, the controller should be able to operate in real-time. To meet the company’s requirements, the following is done. A linear 3ODF model of the system is derived. This is used to predict the states of the buoy in the controller. An MPC algorithm is constructed. In this, the linear model and constraints of the system are included. Then, a simulation environment is built. This is including a non-linear model of OHT’s system. The performance of the controller is tested in the simulation environment. Real-time implementation is an important aspect of the controller. The computational time required by the controller is measured in the simulations. The results imply that the controller stands a chance of being real-time implementable. However, make sure that it can be run in real-time it should be tested on the control unit that OHT plans to use in their system. A linear model of the system is used in the controller to predict the future states o the buoy. It is important that the predictions are accurate for the controller to control the system in an optimal way. Hence, the validity of the linear model is investigated. The controller is managing to predict some states better than others. However, the controller is doing a fine job with controlling the system in terms of generated power. Thus the linear model is considered to be valid for the application. An advantage with controllers based on MPC is the simplicity of tuning the controller. Changes of settings in the controller have a predictable effect on the results. For the settings found in this thesis, the system is performing fine in terms of power generation. However, more work is needed to find more optimal settings.

There is a rising concern about the effects of noise on human health. The noise from our technologies and comforts that evokes a negative physiological response as a response, effects like cardiovascular disease, cognitive and hearing impairments are all examples of critical health results stemming from prolonged noise exposure (WHO, 2004 &amp; 2018). A reaction to the insight of the effects of noise pollution is directives and policies to fight noise pollution, both at a European union level but also member state level (EU, 2002). The applied Swedish policy is enforced by the Swedish work environment authority which has given the following provision for indoor environments and workplace design (AFS 2009:2) which states “4 § Work should be planned, conducted and be followed up so that noise exposure is reduced through eliminating noise from its source or is reduced as much as possible. Consideration should also be taken into the technological advancements and the possibilities to reduce noise.”. This is where this master thesis project comes in to develop a modular sound absorbing unit that could help in the fight against noise pollution and reduce the negative effects of prolonged noise exposure. The master thesis is performed as a part of our final master’s degree course in the program- me of industrial design engineering at the Luleå University of Technology. The company Sontech International AB served as client and collaborator for the master thesis. The objective for the project was to develop a modular sound absorbing unit that uses Sontech’s unique sound absorbing materials to break into a new market, diverging from their previous focus on industrial applications. The project was based in the product design specification developed in the inspiration phase of our project, stemming from the data gathered in needfinding and current state analysis, in conjunction with Sontech. The product design specification was split into three segments of need, function and design which was used in the remaining phases of ideation and implementation. From there the ideation phase consisted of different types of brainstorming methods and explorative prototyping to cre- ate a large sum of ideas to later be analysed through a design space evaluation process which resulted in five distinct concepts. The ideation phase was concluded in a selection of the final concepts to be brought into the implementation phase. The implementation phase entailed refinement of the concepts through testing and detail design. The final design concluded in a modular sound absorbing system called Unison which consist of two modes of thinking, vertical aligned units called Acustibrick for building sound absorbing walls. The other is horizontally aligned units called Acustitile made for creating sound absorbing &amp; deflecting roofs. For each of unit there is the option two pick two types of material, acustimet which is an aluminium sheet with micro perforations which gives it its sound absorbing properties. The second material is acustiboard which is a cardboard sheet made of paper honeycomb and two thin outer layers of paper, this outer layer is perforated to give the material its sound absorbing properties. The units are constructed with stamped holes, called interface, which are aligned to allow mounting on different objects depending on the user’s choice. These objects, called the architecture, can be rods, pipes, wires, ropes etc. depending on how the user chooses to implement the system in their environment. This modular system will allow the user to construct their own arrays of units, with their own resources, to shape and better their noise environment. / Det finns en ökande oro över effekterna av buller på människors hälsa. Bullret från vår teknik och bekvämligheter som framkallar en negativ fysiologisk respons som svar, effekter som hjärt-kärlsjukdom, kognitiva och hörselnedsättningar är alla exempel på kritiska hälsoresultat som härrör från långvarig bullerexponering (WHO, 2004 &amp; 2018). En reaktion på insikten om effekterna av bullerföroreningar är direktiv och politik för att bekämpa bullerföroreningar, både på EU-nivå men också på medlemsstatsnivå (EU, 2002). Den tillämpade svenska policyn upprätthålls av Arbetsmiljöverket som har gett följande bestämmelser för inomhusmiljöer och arbetsplatsdesign (AFS 2009:2) där det står “4 § arbete bör planeras, genomföras och följas upp så att bullerexponeringen reduceras genom att eliminera buller från dess källa eller minskas så mycket som möjligt. Hänsyn bör också tas till de tekniska framstegen och möjligheterna att minska bullret. “. Det är här detta examensarbete kommer in för att utveckla en modulär ljudabsorberande enhet som kan hjälpa till i kampen mot buller och minska de negativa effekterna av långvarig bullerexponering. Examensarbetet utförs som en del av vår slutgiltiga magisterkurs i programmet industriell design Engineering vid Luleå tekniska universitet. Företaget Sontech International AB verkade som klient och samarbetspartner för examensarbetet. Målet för projektet var att utveckla en modulär ljudabsorberande enhet som använder Sontechs unika ljudabsorberande material för att bryta sig in i en ny marknad och avvika från deras tidigare fokus på industriella tillämpningar. Projektet baserades på produktdesign specifikationen som utvecklades i inspirations fasen av vårt projekt, som härrör från de data som samlats in i needfinding och current state analys, tillsammans med Sontech. Produktdesign specifikationen delades upp i tre segment av behov, funktion och design som användes i de återstående faserna av ideation och implementation. Ideationsfasen bestod av olika typer av brainstorming-metoder och utforskande prototyper för att skapa en stor summa idéer som senare kunde analyseras genom en utvärderingsprocess som resulterade i fem distinkta koncept. Ideationfasen avslutades i ett urval av de slutgiltiga koncepten som skulle föras in i implementation fasen. Implementeringsfasen innebar förfining av koncepten genom testning och detaljdesign. Den slutliga utformningen slutade med ett modulärt ljudabsorberande system som kallas unison som består av två sätt att tänka, vertikala justerade enheter kallas Acustibrick för att bygga ljudabsorberande väggar. Den andra är horisontellt anpassade enheter kallas Acustitile gjort för att skapa ljudabsorberande &amp; reflekterande tak. För varje enhet finns alternativet att plocka två typer av material, acustimet som är en aluminiumplåt med mikroperforeringar som ger den dess ljudabsorberande egenskaper. Det andra materialet är acustiboard som är en pappskiva gjord av en kärna av papper i ett honeycomb mönster och två tunna yttre lager av papper, detta yttre skikt är perforerad för att ge materialet dess ljudabsorberande egenskaper. Enheterna är konstruerade med stämplade hål, kallas Interface, som är justerade för att tillåta montering på olika objekt beroende på användarnas val. Dessa objekt, som kallas arkitektur, kan vara stavar, rör, ledningar, rep etc. beroende på hur användaren väljer att implementera systemet i sin omgivning. Detta modulära system gör det möjligt för användaren att konstruera sina egna matriser av enheter, med sina egna resurser, för att forma och förbättra sin bullermiljö.

Empirical models based on linear and nonlinear potential theory that determine the forces on Wave Energy Converters (WECs) are essential as they can be used for structural, mechanical and control system design as well as performance prediction. In contrast to empirical modelling, Computational Fluid Dynamics (CFD) solves the mass and momentum balance equations for fluid domains. CFD and linear potential theory models represent two extreme in terms of capturing the full range of hydrodynamic effects. These are classified as white box models and the structure of these models is completely derived from first principles understanding of the system. In contrast black box models like a Artificial Neural Networks and Auto-Regressive with, Exogenous Input (ARX), map input and output behaviour of a system without any specific physics based structure. Grey box models do not strictly follow a first principles approach but are based on some observations of relationships between the hydrodynamic effects (e.g. buoyancy force) and system state (e.g. free surface height). The objective of this thesis is to propose a data driven grey box modelling approach, which is computationally efficient compared to high fidelity white box mod- els and still sufficiently accurate for the purpose of determining hydrodynamic forces on heaving WECs. In this thesis, a unique data driven approach that combines features from existing works in modelling of WEC and application of nonlinear hysteretic systems is developed. To that end a CFD based Numerical Wave Tank that could provide the data needed to populate the new modelling framework is used. A hull which hydrodynamically represents a Self Reacting Point Absorbers (SRPAs) with heave plate is subjected to pan-chromatic wave fields and is forced to oscillate concomitantly. The results provide evidence that a SRPA with heave plate exhibits nonlinear relationships with motion parameters including relative position, velocity and acceleration. These parameters show causal relationships with the hydrodynamic force. A simulation methodology to establish confidence in the components of a model framework is developed and the hydrodynamic forces on SRPAs with heave plate and bulbous tank have been analyzed and compared. Two sets of numerical simulation were conducted. Firstly, the WECs were restricted to all degrees of freedom and subjected to monochromatic waves and later the WECs were oscillated at various frequency in a quiescent numerical tank. These results were validated against existing experimental data. Earlier attempts by other authors to develop a data-driven model were limited to simple hulls and did not include rate dependent nonlinearities that develop for heave plates. These studies laid the foundation to current work. The model framework developed in this thesis accounts for the nonlinear relationship between force and parameters like velocity and acceleration along with hysteretic relationship between force and velocity. This modelling framework has a nonlinear static, a hysteresis (Bouc-Wen model) and a dynamic (ARX model) block. In this work the Bouc-Wen model is employed to model the hysteresis effect. Five different models developed from this modelling framework are analyzed; two are state dependent models, while the other three required training to identify dynamic order of model equations. These latter models (Hammerstein, rate dependent Hammerstein and rate dependent KGP models) have been trained and validated for various cases of fixed and oscillating HP cylinder. The results demonstrate significant improvement (max 39%) in prediction accuracy of hydrodynamic forces on a WEC with heave plate, for the model in which a rate dependent hysteresis block is coupled with Hammerstein or KGP models. / Graduate