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The paper overviews the modes of vibration of the principal component parts of a brake and their contribution to system instability during noise generation. It is shown that both in-plane and out-of-plane vibration is present and that both can be related to the vibration of the pad. It is further shown that the pad and its region often provide a solution or 'fix' towards noise prevention and it is this area that forms the focus of this investigation. The collective evidence, proposals and associated theory are applied to real brake case studies when it is demonstrated that disc/pad interface 'spragging' may be the source of brake noise. Measurements of the position of the dynamic centre of pressure (CoP) support the theoretical predictions that a leading CoP induces brake noise. Design proposals are suggested that may be applied early in the design phase as a means to reduce the propensity of a brake to generate noise.

The advantages of Integral Abutment Bridges (IABs) include reduced maintenance costs and increased useful life spans. However, comprehensive and practical analysis tools for design of IABs have not been developed to account for the impacts of thermal displacements on abutment and foundation components, including the components of mechanically stabilized earth (MSE) walls that are often used around the abutment piling. During this research, over 65 three-dimensional numerical analyses were performed to investigate and quantify how different structural and geotechnical bridge components behave during thermal expansion and contraction of the bridge deck. In addition, separate three-dimensional numerical models were developed to evaluate the usefulness of corrugated steel pipes around the abutment piles. The results of this research quantify the influence of design parameter variations on the effects of thermal displacement on system components, and thus provide guidelines for IAB design, where none had existed before. One of the findings is that corrugated steel pipes around abutment piles are not necessary. One of the most important products of this research is an easy-to-use Excel spreadsheet, named IAB v2, that not only quantifies the impact of thermal displacement in the longitudinal direction, but also in the transverse direction when the abutment wall is at a skew angle to the bridge alignment. The spreadsheet accommodates seven different pile sizes, which can be oriented in weak or strong directions, with variable offset of the abutment from the MSE wall and for variable skew angles. The spreadsheet calculates the increment of displacements, forces, moments, and pressures on systems components due to thermal displacement of IABs. / Ph. D.

O sucesso da terapia reabilitadora com implantes requer um equilíbrio entre fatores biológicos e mecânicos. Os fatores biológicos são inúmeros, já os mecânicos associam-se à instabilidade da interface implante-intermediário protético. Com base nestas informações, este estudo busca criar um aparelho com o qual será possível avaliar e comparar a resistência e a estabilidade da interface implante-intermediário protético em implantes de diferentes tipos de sistema de conexão e componentes protéticos, após a aplicação de carga simulada, que será realizada por meio de um ensaio dinâmico de fadiga rotacional, também conhecido como flexão rotativa. Para a criação deste aparelho, vários procedimentos com base em princípios de usinagem CNC (Controle Numérico Computadorizado), engenharia elétrica e física foram utilizados. Os futuros testes e resultados, utilizando-se esse aparelho para realizar o ensaio de fadiga, serão publicados em trabalhos futuros. Para o desenvolvimento dos modelos de corpos de prova a serem analisados na máquina de ensaio, foram utilizados implantes do tipo hexágono externo (Neodent) de 3,75mm de diâmetro x 11.5mm de comprimento. Ao término do desenvolvimento, obteve-se um aparelho confiável, resistente e extremamente versátil; podendo-se facilmente variar a carga exercida e a frequência de rotação, sendo assim possível executar inúmeras combinações de ensaios de fadiga. Esse estudo demonstrou a possibilidade e viabilidade de desenvolver um aparelho adequado para realizar um ensaio de fadiga, de pequena dimensão (portátil) e a um custo significativamente inferior do que comprar um aparelho próprio para tal fim. / The success of a rehabilitation therapy with implant fixtures requires a balance between biological and mechanical factors. The biological factors are innumerable, however the mechanics associate it whit instability of the implant-abutment interface. On the basis of these information, the aim of this study is to create a device which it will be possible to evaluate and to compare the resistance and the stability of the implant-abutment interface whith implants of different connection system and abutments, after the simulated load application, that will be carried through a dynamic assay of rotational fatigue load, also known as rotary bending. For the creation of this device, some procedures on the basis of principles of milling CNC (Computerized Numerical control), electric and physical engineering had been used. The future tests and results, using this device to carry through the fatigue assay, will be published in future works. For the development of the body test to be analyzed in the assay machine, implant fixtures of external hexagon type (Neodent) of 3,75mm of diameter x 11mm of length had been used. In the ending of the development, a trustworthy, resistant and extremely versatile device was gotten; being able itself easily to vary the exerted load and the frequency of rotation, being been thus possible to execute innumerable combinations of fatigue assays. This study demonstrated the possibility and viability of it developing an adequate device to carry through an assay of fatigue, of small dimension (portable) and the significantly inferior cost of what if to buy a proper device for such end.

Low-strength cellular concrete consists of a cement slurry that is aerated prior to placement. It remains a largely untested material with properties somewhere between those of soil, geofoam, and typical controlled low-strength material (CLSM). The benefits of using this material include its low density, ease of placement, and ability to self-compact. Although the basic laboratory properties of this material have been investigated, little information exists about the performance of this material in the field, much less the passive resistance behavior of this material in the field.In order to evaluate the use of cellular concrete as a backfill material behind bridge abutments, two large-scale tests were conducted. These tests sought to better understand the passive resistance, the movement required to reach this resistance, the failure mechanism, and skew effects for a cellular concrete backfill. The tests used a pile cap with a backwall face 5.5 ft (1.68 m) tall and 11 ft (3.35 m) wide. The backfill area had walls on either side running parallel to the sides of the pile cap to allow the material to fail in a 2D fashion. The cellular concrete backfill for the 30<&degree> skew test had an average wet density of 29.6 pcf (474 kg/m3) and a compressive strength of 57.6 psi (397 kPa). The backfill for the 0<&degree> skew test had an average wet density of 28.6 pcf (458 kg/m3) and a compressive strength of 50.9 psi (351 kPa). The pile cap was displaced into the backfill area until failure occurred. A total of two tests were conducted, one with a 30<&degree> skew wedge attached to the pile cap and one with no skew wedge attached.It was observed that the cellular concrete backfill mainly compressed under loading with no visible failure at the surface. The passive-force curves showed the material reaching an initial peak resistance after movement equal to 1.7-2.6% of the backwall height and then remaining near this strength or increasing in strength with any further deflection. No skew effects were observed; any difference between the two tests is most likely due to the difference in concrete placement and testing.

Foi analisada a variação da pré-carga de parafusos durante os cinco primeiros minutos depois de cada uma de cinco seqüências aperto e desaperto de parafusos de implantes dentários com diferentes sistemas de retenção pilar/implante. Extensômetros foram colados no terço cervical de implantes com interface de hexágono externo, hexágono interno e cone Morse. Um procedimento controlado de aperto e desaperto dos parafusos permitiu o arquivo dos valores de torque reverso, em relação ao aperto, e o campo de tensões gerado sobre o terço cervical dos implantes resultante da pré-carga do parafuso para cada uma das seqüências. Foram estudadas 30 amostras de implantes/pilares, dividas em oito grupos: implantes de hexágono externo com intermediário Munhão Universal e parafusos de titânio (Neodent, Curitiba, Brasil) apertados a 32 N.cm (EH.Ti.32); hexágono externo, Munhão Universal, parafuso de titânio recoberto por DLC, 32 N.cm (EH.dlc.32); hexágono interno, Munhão Universal, parafuso de titânio, 20 N.cm (IH.Ti.20); cone Morse, Munhão Universal peça única, 20 N.cm (MT.OP.20); cone Morse, Munhão Universal peça única, 32 N.cm (MT.OP.32); Cone Morse, Munhão Universal parafuso passante, 10 N.cm (MT.TS.10); no sétimo grupo foram usados as mesmas amostras do grupo MT.TS.10 a 10 N.cm, porém o desaperto foi realizado pelo intermediário (MT.TS.10.A); para o último grupo foram usados as mesmas amostras do grupo MT.TS.10 e MT.TS.10.A, porém o aperto dos parafusos foi de 15 N.cm e o desaperto também se deu pelo o intermediário (MT.TS.15.A). Os valores médios e desvio padrão (dp) de pré-carga encontrados para todas as seqüências de cada grupo foram de: EH.Ti.32 (27,75; dp 7,70); EH.dlc.32 (40,17; dp 10,16); IH.Ti.20 (219,61; dp 75,47); MT.OP.20 (129,19; dp 116,71); MT.OP.32 (137,97; dp 47,53); MT.TS.10 (39,55; dp 13,96); MT.TS.10.A (126,72; dp 44,05); MT.TS.15.A (194,41; 68,48). Entre os diferentes sistemas de retenção pilar/implante estudados, pode-se concluir que: existem relações únicas entre o valor de torque aplicado no parafuso e a pré-carga gerada sobre o terço cervical do implante, essas são diretamente influenciados pelo desenho da interface pilar/implante, tipo de parafuso de retenção e valor de torque aplicado; não foi observada perda de pré-carga dos parafusos de pilares, nem perda de resistência à torção no sentido anti-rotacional dos parafusos depois de esperados 5 minutos em 5 seqüências de aperto/desaperto. / The preload screw variation for the first five minutes after each one of five torque/untorque sequences from different implant/abutment retention systems was evaluated. Strain gauges were attached over the cervical third of external hex, internal hex and Morse taper implants. A controlled torque/untorque procedure allowed the record from the preload and untorque values of the samples in each one of the sequences. Thirty implant/abutment samples, divided in eight groups were studied: external hex implants with Universal post and titanium screws (Neodent, Curitiba, Brazil) screwed to 32 N.cm (EH.Ti.32); external hex, Universal post, DLC covered screw, 32 N.cm (EH.dlc.32); internal hex, Universal post, titanium screw, 20 N.cm (IH.Ti.20); Morse taper, single piece Universal post, 20 N.cm (MT.OP.20); Morse taper, single piece Universal post, 32 N.cm (MT.OP.32); Morse taper, Universal post trespassing screw, 10 N.cm (MT.TS.10); the same samples from the MT.TS.10 group were used for the seventh group, screwed to 10 N.cm, but the untorque was performed by the abutment (MT.TS.10.A); the same samples used with the MT.TS.10 and the MT.TS.10.A were used for the last group, but the screws were tightened to 15 N.cm and the untorque remained by the abutment (MT.TS.15.A). The mean and the stardad deviation (DP) found for the preloss in all the five sequences were of: EH.Ti.32 (27.75; SD 7.70); EH.dlc.32 (40.17; SD 10.16); IH.Ti.20 (219.61; SD 75.47); MT.OP.20 (129.19; SD 116.71); MT.OP.32 (137.97; SD 47.53); MT.TS.10 (39.55; SD 13.96); MT.TS.10.A (126.72; SD 44.05); MT.TS.15.A (194.41; SD 68.48). For the retention systems studied, it could be concluded that: there are single relations between screw untorque and preload over the implant cervical third, these are directely influenced by the implant/abutment interface design, screw type and torque value; there were not found post screw preload loss, neither torque resistance at the anti-rotational direction from the screws after the first five minutes in five torque/untorque sequences.

Objetivo. Avaliar a capacidade de selamento e a adaptação de intermediários UCLA, com ou sem uma cinta de cobalto-cromo (CoCr), em um sistema de implante de hexágono externo. Materiais e métodos. 120 implantes hexágono externo (Sistema de Implante Nacional - SIN, SP, Brazil) foram dividos em dois grupos (n=60) para receber intermediários UCLA de 6 fabricantes (n=10), com ou sem cinta pré-fabricada de CoCr (n=60). Os intermediários foram fundidos e subdivididos em 12 grupos da seguinte forma: M (Microplant), I (Impladen), S (SIN), Sv (Signo Vinces), T (TitaniumFix), and B (Bionnovation). A capacidade de selamento foi determinada pela colocação de 0.7 &#x3BC;L de azul de toluidina, 0.1% (TB) no espaço interno dos implantes antes do torque nos intermediários. Os espécimes implante-intemediários foram colocados dentro de tubos de 2.0 mL, contendo 0.7 mL de água destilada, a fim de manter a interface implante-intemediário submersa. Amostras de 100 &#x3BC;l foram coletadas após 1, 3, 6, 24, 48, 72, 96 e 144 horas de incubação para medição da absorbância em um espectofotômetro e devolvidos para medidas subsequentes. Para análise estatística, foram empregados o teste ANOVA a dois critérios (p < 0.05) e o teste de Tukey. Microscopia eletrônica de varredura (MEV) foi usado para visualização da adaptação da interface implante-intermediário. Resultados. Os grupos M, Sv, e T sem cinta CoCr apresentaram completa liberação de corante (TB) em 1 h, enquanto que nos grupos I, S, e B, a liberação do corante ocorreu em 3, 24 e 96 h, respectivamente. Para os intermediários com cinta préfabricada, a completa liberação de corante ocorreu em 6 h para o grupo S, em 24 h para os grupos Sv, T e B, e em 72 h para os grupos M e I. Foram observados desajustes na interface implante/intermediário em todos os grupos. Os desajustes mais evidentes foram observados para os grupos M e T, sem cinta de CoCr. Conclusões. A completa liberação de corante foi observada em diferentes períodos de tempo para todos intermediários UCLA, independentemente, da presença ou não da cinta CoCr. Foram observados espaços ou desajustes na interface implante/intermediário em todos os grupos. / To evaluate the effect of the presence of a prefabricated cobalt-chromium (CoCr) margin in a universal castable long abutment (UCLA) in the sealing capability and fit of the implant-abutment mating zone. Materials andmethods. One-hundred and twenty external hexagon implants (SIN, SP, Brazil) were divided in two groups (n=60 each) to receive UCLA abutments from 6 manufacturers (n=10 each) either with or without a CoCr margin (n=60 each). Abutments were cast and 12 groups were formed and named as: M (Microplant), I (Impladen), S (SIN), Sv (Signo Vinces), T (TitaniumFix), and B (Bionnovation). Sealing was determined by placing 0.7 &#x3BC;L of 0.1% toluidine blue (TB) in the implant wells before abutment torquing. Implant-abutment samples were placed into 2.0 mL vials containing 0.7 mL of distilled water to maintain the implant-abutment interface submerged. Aliquots of 100 &#x3BC;l of water were retrieved at 1, 3, 6, 24, 48, 72, 96 and 144 hours incubation times for absorbance measurement in a spectrophotometer, and returned for repeated measurements. Two-way ANOVA (p < 0.05) and Tukey\'s test were used. Scanning electron microscopy (SEM) was used for observation of the implant-abutment fit. Results. Groups M, Sv, and T without the CoCr margin resulted in complete release of TB at 1 h, whereas I, S, and B did at 3, 24 and 96 h, respectively. Complete leakage in abutments with the prefabricated marginoccurredat 6 h for S, 24 h for Sv, T and B, and 72 h for M and I. Implant/abutment gaps were observed in all groups. A poorer fit was depicted for groups M and T without the CoCr margin. Conclusions. Complete leakage was observed for all UCLA abutments regardless of the presence of the CoCrmargin. Implant-abutment gaps was observed for all groups.