A study was conducted to determine whether the mandibles of the detrito-/bryophagous groundhopper Tetrix tenuicornis are subject to mechanical wear as a result of feeding, as is the case for grasshoppers that feed on silica-rich grasses. Abrasion was evaluated by measuring the length and width of the 3rd incisor and length of the 4th incisor in adults of different ages collected under natural c...

Introduction Aeolian abrasion is the dominant rock weathering mechanism on Mars. Ventifacts, defined as rocks whose shapes or textures have been modified by windblown particles, are the manifestation of this weathering mechanism and are found on Earth and Mars. Studies of ventifacts and related features at the well-traversed Spirit Mars Exploration Rover (MER) landing site provides insight into...

The purpose of this study was to evaluate the microtensile bond strength of a repair composite resin to a leucite-reinforced feldspathic ceramic (Omega 900, VITA) submitted to two surface conditionings methods: 1) etching with hydrofluoric acid + silane application or 2) tribochemical silica coating. The null hypothesis is that both surface treatments can generate similar bond strengths. Ten ce...

This paper deals with the state-of-the-art information on high-calcium, ASTM Class C fly ash use in cement-based construction materials, such as high-performance concrete, ready-mixed concrete, etc. The major topics included are: properties of fly ash, effects of fly ash inclusion on fresh and hardened concrete, and future research needs. The fresh concrete properties include workability, water...

There is a growing interest in the development polymers based on renewable resources1-2. Polyurethanes constitute a kind of materials that can vary from rubbery to glassy thermoplastics from linear polymers to thermoset. This versatility can be further controlled in terms of processing and composition to fulfil a great versatility that permit the manufacturing of products ranging from expanded ...

The purpose of this study was to investigate the effect of different surface treatments on shear bond strength of saliva-contaminated resin-resin interfaces. Flat resin surfaces were fabricated. In the control group, no contamination or surface treatment was performed. The resin surfaces of the experimental groups were contaminated with saliva and air-dried, and then submitted to: (G1) rinsing ...

The use of roller compacted concrete (R.C.C) without conventional cover in important hydraulic structures is investigated through laboratory observation of abrasion phenomena sujected to high velocity flow and floating particles. The main parameters affecting abrasion and erosion resistance of R.C.C. studied in the present study include: "Mixed Hydraulic&#10&#10Mean Radius" (which collectively ...

OBJECTIVES The aim of the present study was to test cutting efficiency of different materials against conventional alumina in an air abrasion system. MATERIALS AND METHODS The powder samples were divided into three groups: Group 1 - alumina (control), Group 2 - 45S5 bioactive glass, and Group 3 - hydroxyapatite. 30 microscope glass slides of 0.5 mm thickness were used as an alternative of hum...

Original scientific paper The experiment centres on two and three body abrasion in three-phase waste-based composite systems. The composite systems abrasion resistance is defined not only by the physical-mechanical relationships of the separate phases of the composite, but also by the mutual interaction of the phases and on the matrix-filler interface. To describe the composite system abrasion ...

Articular cartilage repair was followed for one year in skeletally mature dogs after destabilisation by anterior cruciate ligament transection of the stifle joint (CT), abrasion of the inferior medial condyle (ABR) to bleeding bone, or anterior cruciate transection followed by chondral abrasion (CT/ABR). ABR animals formed repair cartilage at the abrasion site (ABR and CT/ABR) at six months as ...