O MTA (Agregado Trióxido Mineral) tem sido utilizado na endodontia com diferentes finalidades terapêuticas. Essencialmente ele é constituído pelo cimento Portland acrescido de um radiopacificador. Entre seus componentes, é destacada a presença do arsênico, o qual sofre variação de concentração em função da origem do calcário. A dúvida é que se diferentes concentrações de arsênico representam alguma influência na sua biocompatibilidade. O objetivo deste estudo foi avaliar, microscopicamente, a reação tecidual em subcutâneo de ratos frente a cimentos Portland contendo diferentes concentrações de arsênico. Foram utilizados 36 ratos Wistar albinos, distribuídos em 4 grupos experimentais segundo o material empregado perfazendo um total de 6 implantes por período (15, 30 e 60 dias). A lateral dos tubos serviram como grupo controle. Após 15, 30 e 60 dias, os animais foram mortos e os espécimes foram preparados histotecnicamente para análise microscópica. Os dados da avaliação morfométrica foram submetidos à análise de variância a dois critérios (ANOVA) e teste de Tukey para a comparação (p<0,05). Os resultados mostraram uma maior densidade de volume de células inflamatórias aos 15 dias, com redução dessa densidade com o passar do tempo para todos os materiais. Os resultados da análise descritiva mostraram inflamação crônica induzida pelos materiais, com intensidade de leve a moderada, e organização de uma cápsula fibrosa ao redor de todos os espécimes e em todos os períodos. Os cimentos analisados produziram respostas inflamatórias semelhantes, mesmo apresentando quantidades diferentes de arsênico na composição, apenas com diferença estatisticamente significante entre o cimento Portland cinza Votoran e os demais cimentos nos três períodos estudados. / The MTA (Mineral Trioxide Aggregate) has been used in Endodontics for different therapeutic purposes. Essentially, it is composed of Portland cement with addition of a radiopacifier. Its components include arsenic, whose concentration is variable according to the origin of the calcareous. There is doubt whether different arsenic concentrations might influence its biocompatibility. This microscopic study evaluated the reaction of subcutaneous tissue of rats to Portland cements containing different arsenic concentrations. The study was conducted on 36 albinus Wistar rats, divided in 12 animals for each study group. Each animal received two implants of polyethylene tubes, completely filled with the test cements, and the lateral aspect of the tubes was taken as control group. The animals were killed after 15, 30 and 60 days and the specimens were submitted to histotechnical preparation for microscopic analysis. Data of the morphometric analysis were submitted to two-way analysis of variance (ANOVA) and the Tukey test for comparison (p<0.05). The results evidenced greater density of volume of inflammatory cells at 15 days, which was reduced with time for all materials. The results of this descriptive analysis demonstrated chronic inflammation induced by the materials, of mild to moderate intensity, and organization of a fibrous capsule around all specimens and in all periods. The cements induced similar tissue responses, despite the different arsenic concentrations in their composition.

O MTA (Agregado Trióxido Mineral) tem sido utilizado na endodontia com diferentes finalidades terapêuticas. Essencialmente ele é constituído pelo cimento Portland acrescido de um radiopacificador. Entre seus componentes, é destacada a presença do arsênico, o qual sofre variação de concentração em função da origem do calcário. A dúvida é que se diferentes concentrações de arsênico representam alguma influência na sua biocompatibilidade. O objetivo deste estudo foi avaliar, microscopicamente, a reação tecidual em subcutâneo de ratos frente a cimentos Portland contendo diferentes concentrações de arsênico. Foram utilizados 36 ratos Wistar albinos, distribuídos em 4 grupos experimentais segundo o material empregado perfazendo um total de 6 implantes por período (15, 30 e 60 dias). A lateral dos tubos serviram como grupo controle. Após 15, 30 e 60 dias, os animais foram mortos e os espécimes foram preparados histotecnicamente para análise microscópica. Os dados da avaliação morfométrica foram submetidos à análise de variância a dois critérios (ANOVA) e teste de Tukey para a comparação (p<0,05). Os resultados mostraram uma maior densidade de volume de células inflamatórias aos 15 dias, com redução dessa densidade com o passar do tempo para todos os materiais. Os resultados da análise descritiva mostraram inflamação crônica induzida pelos materiais, com intensidade de leve a moderada, e organização de uma cápsula fibrosa ao redor de todos os espécimes e em todos os períodos. Os cimentos analisados produziram respostas inflamatórias semelhantes, mesmo apresentando quantidades diferentes de arsênico na composição, apenas com diferença estatisticamente significante entre o cimento Portland cinza Votoran e os demais cimentos nos três períodos estudados. / The MTA (Mineral Trioxide Aggregate) has been used in Endodontics for different therapeutic purposes. Essentially, it is composed of Portland cement with addition of a radiopacifier. Its components include arsenic, whose concentration is variable according to the origin of the calcareous. There is doubt whether different arsenic concentrations might influence its biocompatibility. This microscopic study evaluated the reaction of subcutaneous tissue of rats to Portland cements containing different arsenic concentrations. The study was conducted on 36 albinus Wistar rats, divided in 12 animals for each study group. Each animal received two implants of polyethylene tubes, completely filled with the test cements, and the lateral aspect of the tubes was taken as control group. The animals were killed after 15, 30 and 60 days and the specimens were submitted to histotechnical preparation for microscopic analysis. Data of the morphometric analysis were submitted to two-way analysis of variance (ANOVA) and the Tukey test for comparison (p<0.05). The results evidenced greater density of volume of inflammatory cells at 15 days, which was reduced with time for all materials. The results of this descriptive analysis demonstrated chronic inflammation induced by the materials, of mild to moderate intensity, and organization of a fibrous capsule around all specimens and in all periods. The cements induced similar tissue responses, despite the different arsenic concentrations in their composition.

Origami is making an impact in engineering as solutions to problems are being found by applying origami principles (eg. flat-foldability) and using specific crease patterns as inspiration. This thesis presents an in-depth analysis of a particular origami fold -- the waterbomb base -- to facilitate its use in future engineering problems. The watebomb base is of interest due to its familiarity to the origami community, simple topology (can be made by folding a single sheet of paper four times), scalability, generalizability, and interesting kinetic behavior. It can behave as a nonlinear spring as well as a one- or two-way bistable mechanism. This thesis presents models of the kinetic behavior of the traditional waterbomb base as well as some non-traditional variants to be used as tools in future development of waterbomb-base-inspired mechanisms. In all cases considered here, developability as well as rotational symmetry in both the geometry and motion of the mechanisms are assumed. The thesis provides an introduction to origami and reviews some of the ways in which it has been studied and applied in engineering fields. The waterbomb base is also presented as a specific origami fold with practical application potential. Models for the behavior of the traditional waterbomb base are introduced and its potential usefulness as a testbed for actuation methods is discussed. Models are developed for its kinematic and bistable behavior, including the forces needed to transition between stable states. These models are validated by comparison to physical prototype testing and finite element analysis. The thesis introduces the generalized waterbomb base (WB) and generalized split-fold waterbomb base (SFWB). The WB maintains the pattern of alternating mountain and valley folds around the vertex but in this generalized case any even number of folds greater than or equal to 6 is allowed. An SFWB is created by splitting each fold of a WB into two “half folds”, effectively doubling the number of folds and links but halving the deflection at each fold. The same models that were developed for the traditional waterbomb base are developed for the WB and the SFWB and a few potential applications are discussed.

Fragestellung der Arbeit: Aus der Literaturbetrachtung wird deutlich, dass unterschiedlichste Testverfahren zur Ermittlung der mechanischen Eigenschaften von Laufschuhen eingesetzt. Bisher gibt es kein standardisiertes und allgemein anerkanntes mechanisches Testverfahren. Im Gegensatz zu biomechanischen Untersuchungen verwendet bei mechanischen Messungen nahezu jeder Autor ein anderes Prüfverfahren. Wichtige Entscheidungsprozesse, welche zur Entwicklung des jeweiligen Prüfverfahrens führen, werden gar nicht oder nur unzureichend erläutert. Daher ist es nicht möglich eine generelle Vorgehensweise zur Erstellung eines neuen Prüfverfahrens abzuleiten. Aus den diskutierten Studien kann man schlussfolgern, dass bisherige mechanische Testverfahren die biomechanischen Zusammenhänge nur ungenügend abbilden können. Das übergeordnete Ziel dieser Arbeit ist es daher, ein allgemeingültiges mechanisches Prüfverfahren zu entwickeln, welches es ermöglicht, die Materialeigenschaften eines Laufschuhs im Rückfußbereich zu untersuchen. Ein wesentlicher Punkt dieser Arbeit ist es dabei, die mechanischen Eingabeparameter auf eine möglichst breite Basis von biomechanischen Messdaten aufzubauen. Dazu werden verschiedene biomechanische Messungen durchgeführt und mit den Ergebnissen früherer Studien verglichen. Durch diese Vorgehensweise soll dem Anspruch der Allgemeingültigkeit Rechnung getragen werden. Ein wesentliches Anliegen dieser Arbeit ist darüber hinaus die Dokumentation und Diskussion aller wichtigen Entscheidungsschritte, die zu diesem Prüfverfahren führen. Um die gesetzten Ziele zu erreichen, werden folgende Fragestellungen beantwortet: F1 - Welche Stempelgeometrie muss für das zu entwickelnde Testverfahren verwendet werden um der anatomischen Belastungsfläche zu entsprechen? F2 - Wie muss der Stempel ausgerichtet werden um die Kraft in das Material einleiten zu können? F3 - Wie hoch sind die verwendeten Kräfte zur Belastung des Rückfußbereiches beim Laufen? F4 - Ermöglicht das mechanische Prüfverfahren eine zuverlässige Bestimmung der mechanischen Laufschuheigenschaften? F5 - Ermöglicht das mechanische Prüfverfahren eine Bestimmung funktionaler Laufschuheigenschaften?

Belastningen vid tryck vinkelrätt mot fiberriktningen är ett problem vid höga träbyggnader med träregelstomme vid till exempel mötet mellan regel och syll. Ettmaterial som blivit alltmer populärt i Sverige är korslimmat trä, som benämns som KL-trä, där lameller korsvis limmas samman till en skiva. Experiment har tidigare utförts på materialet och det har visat att en bräda av KL-trä, som idag inte tillverkas, klarar ett högre stämpeltryck än en vanlig bräda av konstruktionsvirke, vilket skulle kunna vara en lösning på problemen vid tryck vinkelrätt fiberriktningen i höga träbyggnader. Syftet med detta examensarbete är att bestämma KL-träets karakteristiska tryckkraftskapacitet och tryckhållfasthet för två uppställningar av KL-trä där andelar vinkelräta och parallella lameller som belastas i tvärsnittet skiljer sig åt. Det undersöks också hur lasten fördelar sig på lamellerna som belastas parallellt med fiberriktningen och vinkelrätt mot fiberriktningen i en bräda av KL-trä samt att teoretiska beräkningar av tryckkraftskapaciteten utfördes i mitten och i änden på brädan. Examensarbetet omfattades av tre olika metoder där standarden SS-EN 408 för tryck vinkelrätt mot fiberriktningen användes för att bestämma tryckkraftskapacitet och tryckhållfasthet för de två uppställningarna av KL-trä genom materialtester i en hydraulisk press. Lastfördelningen mellan lamellerna i en KL-trä bräda undersöktes genom stämpeltrycktester i änden på brädan och återspeglar ett verkligt möte mellan regel och syll. En solid bräda av KL-trä, en bräda där de vinkelräta lamellerna sågats bort samt en bräda av konstruktionsvirke belastades för att undersöka differensen i stämpeltryck. Teoretiska beräkningar utfördes på KL-trä brädorna både i mitten och i änden genom att de olika lamellerna beräknades som enskilda brädor enligt Eurokod 5 samt EKS11 och därefter summerades alla lameller för KL-trä brädan. Resultaten visade att den uppställningen av KL-trä med störst andel lameller som belastades parallellt med fiberriktningen erhöll störst tryckkraftskapacitet och fick högst tryckhållfasthet. I brädan av KL-trä tog de lameller som belastades parallellt med fiberriktningen upp ungefär fyra femtedelar av lasten i tvärsnittet som belastades. De teoretiska beräkningarna som utfördes gav en lägre tryckkraftskapacitet än resultaten från de experimentella testerna. För materialtest 1 där lamellerna fördelade sig 58 % vinkelräta lameller och 42 % parallella lameller erhölls karakteristiska värden på 79,7 kN på tryckkraftskapacitet och 18,6 MPa på tryckhållfasthet. För materialtest 2 där lamellerna fördelade sig 42 % vinkelräta lameller och 58 % parallella lameller erhölls karakteristiska värden på 114,6 kN på tryckkraftskapacitet och 26,8 MPa på tryckhållfasthet. Belastningsfördelningen i KL-trä brädan visade att de parallellt belastade lamellerna tog upp en last motsvarande 80,8 % och de vinkelräta lamellerna tog upp en last motsvarande 19,2 %. De teoretiska beräkningarna utnyttjades till 57 % i jämförelse mot maxlasten från de experimentella testerna, både i mitten och på brädans ände. / Compression perpendicular to the grain is today a problem with tall wood buildings with timber-frame at, for example, the meeting between timber stud and the bottom rail. A material that has become increasingly popular in Sweden is cross-laminated timber, which is referred to as CLT, where lamellae are glued together crosswise to a board. Experiments have previously been performed on the material and it has shownthat a board made of CLT, which is not manufactured today, can withstand a higher pressure than an ordinary board made of structural timber, which could be a solution to the problems with compression perpendicular to the grain in tall wood buildings. The purpose of this thesis is to determine the CLTs characteristic compressive force capacity and compressive strength for two formations of CLT where proportions of perpendicular and parallel lamellae that are loaded in the cross section differ. It will also be investigated how loads are distributed on the lamellae which are loaded parallel to the grain and perpendicular to the grain in a board made of CLT and that theoretical calculations of the compressive force capacity were performed in the middle and at the end of the board. The thesis was comprised of three different methods where the standard SS-EN 408 for compression perpendicular to the grain was used to determine compressive forcecapacity and compressive strength for the two formations of CLT through material tests in a hydraulic press. The load distribution between the lamellae in a CLT-boardwas examined by compression tests at the end of the board and reflects a real meeting between a timber stud and the bottom rail. A solid board made of CLT, a board where the perpendicular lamellae were sawn off and a board made of structural timber were loaded to investigate the difference in compression. Theoretical calculations were performed on the CLT-boards both in the middle and at the end through calculating the different lamellae as individual boards according to Eurocode 5 and EKS11 and then all lamellae for the CLT-board were summed. The results showed that the arrangement of CLT with the largest proportion of lamellae parallel to the grain obtained the largest compressive force capacity and had the highest compressive strength. In the CLT-board, the parallel-loaded lamellae took up about four-fifths of the load in the cross-section that was loaded. The theoretical calculations performed gave a lower compressive force capacity than the results of the experimental tests. For material test 1 where the lamellae were distributed 58% perpendicular lamellaeand 42% parallel lamellae, characteristic values of 79.7 kN on compressive capacity and 18.6 MPa on compressive strength were obtained. For material test 2 where the lamellae were distributed 42% perpendicular lamellae and 58% parallel lamellae, characteristic values of 114.6 kN on compressive capacity and 26.8 MPa on compressive strength were obtained. The load distribution in the CLT-plank shown that the parallel-loaded lamellae took up a load corresponding to 80.8% and the perpendicular lamellae took up a load corresponding to 19.2%. The theoretical calculations were used to 57% in comparison with the maximum load from the experimental test, both in the middle and at the end of the board.

Fragestellung der Arbeit: Aus der Literaturbetrachtung wird deutlich, dass unterschiedlichste Testverfahren zur Ermittlung der mechanischen Eigenschaften von Laufschuhen eingesetzt. Bisher gibt es kein standardisiertes und allgemein anerkanntes mechanisches Testverfahren. Im Gegensatz zu biomechanischen Untersuchungen verwendet bei mechanischen Messungen nahezu jeder Autor ein anderes Prüfverfahren. Wichtige Entscheidungsprozesse, welche zur Entwicklung des jeweiligen Prüfverfahrens führen, werden gar nicht oder nur unzureichend erläutert. Daher ist es nicht möglich eine generelle Vorgehensweise zur Erstellung eines neuen Prüfverfahrens abzuleiten. Aus den diskutierten Studien kann man schlussfolgern, dass bisherige mechanische Testverfahren die biomechanischen Zusammenhänge nur ungenügend abbilden können. Das übergeordnete Ziel dieser Arbeit ist es daher, ein allgemeingültiges mechanisches Prüfverfahren zu entwickeln, welches es ermöglicht, die Materialeigenschaften eines Laufschuhs im Rückfußbereich zu untersuchen. Ein wesentlicher Punkt dieser Arbeit ist es dabei, die mechanischen Eingabeparameter auf eine möglichst breite Basis von biomechanischen Messdaten aufzubauen. Dazu werden verschiedene biomechanische Messungen durchgeführt und mit den Ergebnissen früherer Studien verglichen. Durch diese Vorgehensweise soll dem Anspruch der Allgemeingültigkeit Rechnung getragen werden. Ein wesentliches Anliegen dieser Arbeit ist darüber hinaus die Dokumentation und Diskussion aller wichtigen Entscheidungsschritte, die zu diesem Prüfverfahren führen. Um die gesetzten Ziele zu erreichen, werden folgende Fragestellungen beantwortet: F1 - Welche Stempelgeometrie muss für das zu entwickelnde Testverfahren verwendet werden um der anatomischen Belastungsfläche zu entsprechen? F2 - Wie muss der Stempel ausgerichtet werden um die Kraft in das Material einleiten zu können? F3 - Wie hoch sind die verwendeten Kräfte zur Belastung des Rückfußbereiches beim Laufen? F4 - Ermöglicht das mechanische Prüfverfahren eine zuverlässige Bestimmung der mechanischen Laufschuheigenschaften? F5 - Ermöglicht das mechanische Prüfverfahren eine Bestimmung funktionaler Laufschuheigenschaften?:1 Einführung - S.1 2 Forschungsstand - S.5 3 Fragestellung der Arbeit - S.86 4 Methodisches Verfahren - S.88 5 Erstellung des mechanischen Testverfahrens - S.96 6 Evaluierung des Testverfahrens - S.126 7 Anwendungsmöglichkeiten - S.172 8 Reflektion der Ergebnisse - S.178 9 Literatur - S.180 10 Anhang - S.191 Danksagung - S.196 Lebenslauf - S.198 Erklärung - S.200