This master's thesis is engaged in development of new sanding units for a specific type of rail vehicle. Sanding in rail transport is application of most commonly silica sand into wheel-rail contact. Thanks to its reliability it is still the most widely used method for removing contaminants and improving adhesion in that contact. Sanding devices were developed in cooperation with corporation, which deals with production of rail transport equipment, among other things. The most important part of sanding device is sand dispenser. Dispensers were experimentally developed at the test station in the cooperating corporation. Dispensers were tested for utilization conditions on the locomotive of the train and conditions for trams and light rail vehicles. Furthermore, sand boxes have been designed for specific type of rail vehicle and new type of sand discharge tube, which directs sand directly into wheel-rail contact was designed too.

As lesões cervicais não cariosas (LCNCs) são definidas pela perda de estrutura dental na junção cemento/esmalte que envolve três mecanismos de estresse mecânico (tensão), atrito (fricção) e erosão (degradação química).. Existem tratamentos preventivos e dessensibilizantes para o principal sintoma das LCNCs, a hipersensibilidade dentinária cervical (HDC), porém, em casos que há perda de estrutura dental maior que 1mm é necessário realizar uma intervenção restauradora. Dessa forma, o objetivo deste estudo foi avaliar a resistência de união da dentina erodida e abrasionada modificada com diferentes pré-tratamentos e posteriormente restauradas com resina composta, através do teste de microtração. Para tanto, foram selecionados 40 molares humanos íntegros, que tiveram as porções oclusais seccionadas até exposição da dentina. Os espécimes passaram por desafio erosivo e abrasivo em uma ciclagem de 5 dias. Após os desafios, os espécimes receberam os tratamentos de superfície (n=10): G1: controle sem tratamento; G2: tratamento de superfície com ponta diamantada; G3: jateamento com óxido de alumínio, G4: ciclagem com enxaguatório fluoretado Elmex Erosion. Feito isso os espécimes foram restaurados, seccionados em palitos e submetidos ao teste de microtração em uma máquina universal de ensaios a 0,5mm/min. Para a analise estatística, foi utilizado o teste paramétrico de análise de variância (ANOVA) um fator e o teste auxiliar de Tukey. Foi observado que não houve diferença entre os tratamentos com ponta diamantada, óxido de alumínio e enxaguatório fluoretado. O único grupo a se diferenciar dos demais foi o grupo controle que apresentou valores de resistência de união inferiores. Dentro das limitações de um trabalho in vitro, conclui-se que os tratamentos de superfície estudados são procedimentos indicados para melhorar a adesão dental frente à necessidade de restaurar uma LCNC. / Non-carious cervical lesions (NCCLs) are defined by loss of dental structure at the cement/enamel junction involving three mechanisms of mechanical stress (tension), friction and erosion (chemical degradation). There are preventive and desensitizing treatments for the the main symptom of NCCLs, cervical dentin hypersensitivity (CDH), but in cases where there is loss of tooth structure greater than 1mm, a restorative intervention is necessary. Thus, the objective of this study was to evaluate the bond strength of the eroded and abraded dentin modified with different pre-treatments and later restored with composite resin, through the microtensile test. For this, 40 sound human molars were selected, which had the occlusal portions sectioned until exposure of the dentin. The specimens underwent erosive and abrasive challenge in a 5-day cycling. After the challenges, the specimens received the surface treatments (n = 10): G1: control without treatment; G2: surface treatment with diamond tip; G3: sandblasting with aluminum oxide, G4: cycling with fluoridated rinse Elmex Erosion. After this, the specimens were restored, sectioned on sticks and subjected to the microtensile test in a universal test machine at 0.5mm/min. For statistical analysis, the parametric analysis of variance (ANOVA) one factor and the Tukey auxiliary test were used. It was observed that there was no difference between treatments with diamond tip, aluminum oxide and fluoride. The only group to differentiate from the others was the control group that presented inferior bond strength values. Within the limitations of an in vitro work, it is concluded that the surface treatments studied are procedures indicated to improve dental adhesion in view of the need to restore NCCL.