Fundação de Amparo a Pesquisa do Estado de Minas Gerais / The widening of the root canal increases its fracture risk and is not clear yet, the influence of the materials and techniques used to restore these teeth. The aim of this study was to evaluate the effect of different posts and restorative techniques in the fracture resistance, fracture mode and root strain in canals excessively widened. One hundred thirty five standardized bovine roots, with similar dimensions and endodontically treated, were randomly divided in 9 groups (n=15) with the root canals prepared with 10 mm depth and 1.5 mm diameter. All roots received ferrule in the coronal ending with 0.5 mm depth and 2 mm extension. The roots of two reference groups were reconstructed with nickel-chromium metallic cast post-and-core (NMF) and glass fiber post (PFV) with composite resin core. For the experimental groups (weakened roots - wc groups), the root canals were over prepared additionally with the depth of 9 mm and the diameter increased to approximately 3,5 mm. Then the roots were restored with metallic cast post-and-core (wcNMF); glass fiber post (wcPFV); glass fiber post associated with accessory glass - ap - fiber post (wcPFVap); direct composite resin - cr - in the medial and cervical thirds after luting the post (wcPFVcr); direct composite resin associated with accessory posts in the medial and cervical thirds, after luting the post (wcPFVcrap); the post was reembased indirectly with composite resin - icr - (wcPFVicr); the post was reembased indirectly with composite resin associated with accessory posts (wcPFVicrap). All posts were fixed with chemical resinous cement, the core was made with composite resin and the roots restored with metallic crown. The samples were submitted to 3x105 mechanical fatigue cycles of 50 N load and fracture resistance measured in a mechanical testing machine with tangential load application (135º). Five samples of each group received two strain gauges adhered in the mesial and buccal surfaces of the root, 1mm below the cervical crown ending, in the center of the tooth, to measure roots strain under continuous 0 to 100 N loading. Fracture mode was classified in accordance to the degree of destruction of the dental structure, in catastrophic or repairable. The data were submitted to ANOVA (2x2)l to one-way and Tukey´s test (α=0.05). The factorial analysis demonstrated significant decrease of the fracture resistance and catastrophic failures for the wcNMF group. Roots widened canals restored with composite resin and/or accessory fiber posts result in fracture resistance values similar to NMF group, however, these demonstrated more repairable fracture. The strain-gauge analysis didn t present significant differences in the superficial strain of the root. Fiber glass post associated with composite resin or with accessory fiber glass posts, seems to be more indicated as alternative to metallic cast post-and-core in weakened roots, because of the lower risk of catastrophic fractures. / O alargamento do canal aumenta o risco de fratura dentária e ainda não está clara a influência dos materiais e técnicas empregados para restaurar dentes com estas características. Assim, o objetivo deste estudo foi avaliar o efeito de diferentes pinos e técnicas restauradoras na resistência à fratura, padrão de fratura e deformação de raízes com canais excessivamente alargados. Foram empregadas 135 raízes bovinas com dimensões semelhantes, tratadas endodonticamente, aleatoriamente divididas em 9 grupos (n= 15). Os canais foram preparados com 10 mm de profundidade e 1,5 mm de diâmetro e as raízes receberam preparo com férula de 0,5 mm de profundidade e 2 mm de extensão. Dois grupos de referência foram restaurados com retentores intraradiculares metálicos fundidos em níquel-cromo (NMF) e pino de fibra de vidro (PFV) com núcleo de preenchimento em resina composta. Para os demais grupos, os canais radiculares foram alargados na profundidade de 9 mm e o diâmetro aumentado para ±3,5 mm, padronizando a espessura de dentina remanescente em 0,5mm no terço coronário da raiz. Os canais alargados (ca) foram então restaurados com, núcleo metálico fundido (caNMF); pino de fibra de vidro (caPFV); pino de fibra de vidro associado a pinos de fibra de vidro acessórios (caPFVpa); preenchimento direto com resina composta nos terços médio e cervical após cimentação do pino (caPFVrd); preenchimento direto com resina composta associado a pinos acessórios, após cimentação do pino (caPFVrdpa); pino reembasado com resina composta de forma indireta (caPFVri); pino reembasado com resina composta de forma indireta associado a pinos acessórios (caPFVripa). Todos os procedimentos de cimentação foram realizados com cimento resinoso de ativação química, os núcleos de preenchimento em resina composta e as raízes restauradas com coroa total metálica. As amostras foram submetidas a 3x105 ciclos de fadiga mecânica de 50N de carga. Em cinco amostras de cada grupo, dois extensômetros foram aderidos à raiz, um na mesial e outro na vestibular, 1 mm abaixo do limite cervical da coroa, no centro do dente, para mensurar a deformação das raízes sob carregamento contínuo de 0 a 100N. A resistência à fratura (N) das amostras foi então medida em máquina de ensaio mecânico com aplicação de carga tangencial (135º). Os dados foram submetidos à análise de variância fatorial (2x2), para comparar o efeito do tipo de retentor em função do tipo de raiz, e em fator único, para avaliar os métodos de preenchimento, seguido pelo teste de Tukey (α=0,05). O padrão de fratura foi classificado de acordo com o grau de comprometimento da estrutura dentária em catastrófica ou reparável. A análise estatística fatorial demonstrou significativa redução da resistência à fratura e falhas catastróficas para o grupo caNMF. Valores de resistência comparável ao grupo NMF e padrão de fratura reparável foram obtidos em raízes com canais alargados, sempre que a resina composta ou pinos de fibra acessórios foram utilizados. Não houve diferença significante na deformação externa da raiz entre os grupos estudados. Pode-se concluir que o uso de pinos de fibra de vidro, associado ao preenchimento com resina composta e/ou pinos de fibra de vidro acessórios, parece ser mais indicado como alternativa ao núcleo metálico fundido em raízes fragilizadas, devido ao menor risco de fraturas catastróficas. / Mestre em Odontologia

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This report presents a final degree project in mechanical engineering which was performed at Ball Beverage Packaging Fosie AB, Malmoe. The goal of the project was to create a system that could estimate the amount of paint available in a machine that colorizes aluminum cans. The environment that the system was mounted in is demanding and has high requirements on strength, stability and toughness against splashes of ethanol and water-based paint. Moreover, the company initially demanded that the project only used existing holes on the machine for adding equipment. In order to choose a measurement technology for the system, literature studies were performed on laser, ultrasonic devices and weight measurement. These studies were the foundation for a concept analysis using a Pugh’s matrix.Furthermore, with the help of the Pugh’s matrix, the project was directed towards estimating the amount of paint by measuring the weight using load cells. The collected data was supposed to be handled by an Arduino uno R3 board. Following the decision of a direction, seven concepts were designed in Autodesk Inventor with regards to mounting in existing positioning pin-holes.The last concept was manufactured with own hands – under supervision – by processing aluminum rods. Parallel to the manufacturing, the electronic system was programmed and tested by both step-wise removing identical weights, and a by measuring a continuous weight decrease caused by water escaping from a container with holes. The results of these tests showed that the system could perform the desired function.The result of the manufactured concept confirmed that the system could work with the machine but the position in the positioning pin-hole was not optimal as the forces were too low. By creating a provisional mount and testing the system beneath the paint container, it was concluded that the position accumulated more forces. This resulted in an approved modification of the container holder for a permanent mount of the load cell. Followed by this, a large amount of tests showed that the system had good potential of working with the machine but a mount beneath the container was not good as friction from mounting screws had great effect on the read values. / Rapporten behandlar ett kandidatarbete i maskinteknik som utfördes på Ball Beverage Packaging Fosie AB, Malmö. Syftet med arbetet var att skapa ett system för uppskattning av färgmängd i en maskin som färglägger aluminiumburkar. Miljön som systemet monterades i ställde höga krav på hållfasthet, tillförlitlighet och motståndskraft mot stänk från etanol och vattenbaserad färg. Initialt ställde företaget preliminära krav på att endast existerande hål på färgverket fick användas. För att välja givare till systemetutfördes litteraturstudier med avseende på laser, ultraljud och viktavläsning, vilket låg till grund för konceptvalsanalys med en Pughsmatris.Med hjälp av Pughsmatrisen riktades projektet in på att uppskatta färgmängden genom viktavläsning med lastceller, vars data skulle hanteras av ett Arduino uno R3 kort. Detta efterföljdes av att sju koncept skapades i Autodesk Inventor för infästning i existerande sprinthål på kisthållaren. Det sista konceptet tillverkades genom att på egen hand – under uppsikt –maskinbearbeta aluminiumstavar. Parallellt med tillverkningen programmerades och testades elektroniken med stegvis borttagning av vikt och kontinuerligt avrinnande vatten från hålig behållare, vars resultat visade på att systemet klarar den tänkta funktionen. Resultatet av det maskintillverkade konceptet visade att systemet även fungerade på färgverket men att positionen i sprinthålet inte var optimal då för lite krafter upptogs. Genom att tillverka en provisorisk monteringssats och testa systemet monterat under färgkistan påvisades att denna position tog upp avsevärt mer kraft. Detta medförde att kisthållaren maskinbearbetades för permanent montering av lastcell. Ett stort antal olika tester efter slutlig montering visade att systemet har goda möjligheter för att fungera med färgläggningsmaskinen men att montering under kisthållaren inte var lämplig eftersom friktion från bland annat inspänningsskruvar hade betydandeinverkan på de avlästa värdena.

Cette thèse de doctorat porte sur l'étude et la réalisation d'une plateforme de pesage dynamique pour véhicule roulant basée sur un concept d'intégration de la charge. Ce concept est mis en œuvre en vue de pouvoir minimiser la taille et l'encombrement de ce type de dispositif tout en effectuant des pesées présentant des caractéristiques métrologiques acceptables. Nous démontrons tout d'abord au travers de la réalisation d'un prototype et de plusieurs campagnes d'essais, la faisabilité de la méthode utilisée. Nous évaluons dans un deuxième temps les performances présentées par le prototype lors du pesage de véhicules légers roulant jusqu'à des vitesses de 35km/h. Une étude est ensuite menée sur les jauges de déformation piézorésistives et les jauges piézoélectriques réalisées en couches épaisses grâce à des techniques de sérigraphie. Nous caractérisons ces transducteurs avec pour objectif leur utilisation dans des dispositifs de pesage en remplacement des jauges de déformation classiques à filaments métalliques. / This PhD thesis is devoted to the study and implementation of a weigh-in-motion platform for vehicle based on a concept of integration of load. This concept is used to minimize the size of this kind of device while performing weighings with acceptable results. First, we show thanks to a protoype and several test campagns, the feasability of the method used. In a second time, we evaluate the performances of the prototype in terms of precision and repeatability with the dynamic weighing of vehicles at speeds up to 35km/h. A study is finally conducted on thick-film piezoresitive strain gauges and piezoelectric gauges manufacturing by a screen-printing process with cermet and polymer pastes. We characterize these tranducers with the goal of used them as an alternative of conventional foil strain gauges.

Determination of rheological phenomenon is very difficult, because there are many unknown inputs parameters, e.g. concrete age, the size of elements, relative humidity of the surrounding environment, cement hydration rate, temperature influence, type of strain and treatment. This Ph.D. thesis deals with the effective cross-section thickness and its effect on the behaviour of concrete constructions that is how the rheological phenomena change in time as a result of the application or removal of insulation layer from the concrete surface. Long-term experimental measurements of specimens and real bridge constructions were performed. The data collected from these measurements were described, evaluated and mathematical modifications for the standards Model Code 2010 and Model B4 (B3) have been proposed. Using these new computational formulas is possible to take into consideration the changes in the effective cross-section thickness and therefore make the computational models for concrete structures more accurate.

This master´s thesis deals with determination of pressure in the pipe using foil strain gauge. It is calculation of the pressure from the measured strain. The main purpose of this work is devise mathematical-technological models to determinate internal pipe pressure from longitudinal deformation. Devised models were used on data from realized experiment and results were compared with real value of pressures in pipes. This thesis contains three models which were mutually compared. Sensitivity analysis were done on two of these models. Thesis also contains opening research of strain gauge problematics. Description of basic knowledge of physical objects mechanic with focusing on shells also belongs to this theoretical part.

Subject of this effort is development and realization of one-channel data acquisition unit of mechanical quantities and it’s PC software application. Usage of this data acquisition unit is aimed on applications, where resistive strain gages wired as Wheatstone bridge with AC excitation are used. Output voltage of Wheatstone bridge is amplięed, demodulated with excitation voltage, filtered and level shifted for analog to digital conversion via AD converter. Converted digital data are sent via serial bus into microprocessor which sends them into PC for further meaningful representation in software application. Besides sensing bridge output voltage, data acquisition unit also generates AC excitation of Wheatstone bridge. This excitation voltage is generated via DA converter which communicates with microprocessor and converts incoming digital data into analog sine waveform. There is precise voltage reference circuitry for both of these converters. PC application’s task is to visualize measured data in meaningful form and to give tools for further work with measured data. It’s programmed in Python language and it has one independent thread which does reading and computing of incoming data and there is also class which builds graphical user interface and plots measured data into live graph.

Syftet med detta projekt var att skapa en paddlingssensor vilket mäter paddlingskrafteni flera olika riktningar. Detta uppnås genom att skapa en sensor vars kopplingsschema är i enlighet med en wheatstonebrygga och två trådtöjningsgivare som placeras i strategiskt valda positioner. Dessa positioner tillåter sensorn att mäta flera krafter i olika riktningar. Jämfört med tidigare sensorer som endast mäter spänningsskillnaden i en riktning med endast en givare. Trådtöjningsgivarnas positionering utvärderades samt den optimala positioneringen. Sensorn som konstruerades kunde registrera spänningsförändringar som var proportionella till en pålagd vikt. En tydlig linjär korrelation observerades mellan viktökningen och spänningsförändringen. / The purpose of this project was to construct a paddle sensor that has the ability to measure the paddle force in multiple different directions. This can be attained by creating a sensor where the circuitry is in accordance with a wheatstonebridge and strain gauges are strategically placed on predetermined positions. These positions allow the sensor to be able to measure the force in different directions. The positions of the strain gauges were evaluated, and the most optimal placement was chosen. The created sensor was able to register voltage changes which were proportional to an added weight. As the weight increased so did the voltage changes and a clear linear correlation was observed.

Additive manufacturing has recently become an increasingly available, affordable, and versatile technology for industry and enthusiasts alike. One opportunity that this provides is using conductive filament to print electronic sensors and components. This thesis addresses some of the possibilities and limitations of using conductive filament for constructing electronic sensors and components. Using Protopasta Conductive polylactic acid filament, several components were printed and tested. Printed components include resistors, capacitors, strain gauges and touch sensors. To all components connector pad were added to create a uniform interface between filament and metal. Resistors were printed with varying geometry, ranging from lengths 12 mm to 60 mm and height 1 mm to 4 mm. Their resistances were measured and found to range from 250 Ω to 1600 Ω. Circular capacitors were printed with diameters, 2 cm, 3 cm and 4 cm respectively. However, the capacitors showed no capacitance during measurements, indicating that this material with its high resistivity is unsuitable for creating capacitors. Strain gauges and touch sensors were also constructed, showing that there is a potential for using this filament. The strain gauges had a resistance increase that depended heavily on geometry; straight components had a resistance increase up to 15 % for 40° angle bends, where as gauges with bends had close to zero increase. Two proof-of-concept prototypes of touch sensors were also constructed, showing that the material can be used for this purpose. Creating high quality prints with the filament proved difficult; it had a tendency of clogging the printer, printing unevenly, and showed poor layer adhesion. Primary future work is to improve the printing process. / Additiv tillverkning har de senaste decennierna alltmer blivit tillgängligt, billigare och mer mångsidigt, och kan nyttjas av industri och entusiaster. En möjlighet som uppkommit är att additiv tillverkning möjliggör konstruktion med konduktiva filament, för att printa exempelvis sensorer och elektriska komponenenter. Denna rapport behandlar möjligheter och begränsningar av att använda konduktivt filament för sensorer och elektriska komponenter. Med Protopasta Conductive PLA (PolyLactic Acid) filament har flera komponenter printats och testats. Printade komponenter inkluderar resistorer, kondensatorer, töjningsgivare och vidröringssensorer. Till alla komponent har tillagts kontaktytor för att skapa ett enhetligt gränssnitt mellan filament och metall. Resistorer har printats med varierande geometri, från längder mellan 12 mm och 60 mm till tjocklekar mellan 1 mm och 4 mm. Resistanserna mättes och låg mellan 250 Ω och 1600 Ω. Cirkulära kondensatorer printades med diametrarna 2 cm, 3 cm och 4 cm. Däremot visade kondensatorerna ingen kapacitans under mätningar, vilket indikerar att detta material med sin höga resistivitet är olämpligt för att skapa kondensatorer. Töjningsgivare och vidröringssensorer har också konstruerats. Töjningsgivaren har en resistans som beror kraftigt på geometrin; raka komponenter uppvisade en resistansökning på uppemot 15 % för 40° böjningar, medan töjningsgivare med öglor hade en resistansökning nära noll. Två prototyper av vidröringssensorer konstruerades och verifierades, vilket visar att materialet kan användas till detta syfte. Att få högkvalitativa utskrifter med filamentet visade sig vara svårt; filamentet tenderade till att täppa till skrivarens munstycke, ge ojämna utskrifter och uppvisade dålig fästning mellan lagren. Huvudsakligt framtida arbete är att förbättra utskriftsprocessen.

The individual monitoring of cross-country skiers’ technique-related parameters is crucial to identifying possible athlete-individual deficits that need to be corrected in order to optimize the athlete’s performance in competition. To be able to record relevant biomechanical parameters during training in the field, the development of measuring systems exploiting the athlete’s full potential is the key. Known mobile monitoring systems for measuring forces on ski poles use comparably heavy uniaxial load cells mounted on the pole with a data logger also attached to the pole or carried by the athlete. Measurements that are more accurate can be acquired using wire-based systems. However, wire-based systems are highly immobile and only usable when the athletes undergo a stationary test, e.g., on a treadmill. This paper focuses on the functional design of a measuring system using specialized, miniaturized electronics for acquiring data from strain sensors. These data are then used to determine the technique-related parameters pole force and angle of bend. The functional design is also capable of transmitting the acquired data wirelessly via Bluetooth to a smartphone that runs a proprietary app. This approach is advantageous regarding mass, dynamic behavior, analyzing functionality, and signal processing compared to the state of the art.