While the effects of legal and institutional arrangements on political participation are well documented, little attention has been given to the potential participatory effects of one of the United States’ most important electoral laws: constitutionally mandated reapportionment. By severing the ties between constituents and their incumbents, we argue, redistricting raises information costs, lea...

background: the interim restorative materials should have certain mechanical properties to withstand in oral cavity. the aim of this study was to evaluate the hardness and wear resistance ofinterim restorative materials. materials and methods: fifteen identical rectangular shape specimens with dimensions of 2 mm × 10 mm × 30 mm were made from 7 interim materials (tempspan, protemp 3 garant, rev...

background: topical anesthesia has been widely advocated as an important component of atraumatic administration of intraoral local anesthesia. the aim of this study was to use direct observation of children’s behavioral pain reactions during local anesthetic injection using cotton-roll vibration method compared with routine topical anesthesia. materials and methods: forty-eight children partici...

In this work, two different 2D materials, molybdenum disulfide nanoplatelets (MSNP) and graphene (GNP), prepared by electrochemical exfoliation, were used as additives to prepare nanolubricants. The tribological behaviour of the nanolubricants was evaluated under configurations (pure sliding rolling/sliding) using tribometers: an Universal Macro Materials Tester (UMT-3) a Mini Traction Machine ...

This work presents the results of tribological tests Mo and combined coatings TiAlC formed using electrospark alloying (ESA) technology additionally processed thermochemical electrolyte anodic heating (TEAH). ESA makes it possible to form 15–20 µm thick on friction surface, characterized by a high hardness wear resistance. Tribological studies were performed testing block-on-roll pair under 300...

background: some studies have shown that casein phosphopeptide-amorphous calcium phosphate (cpp-acp) and acidulated phosphate fluoride (apf) gel can protect teeth against erosion. the aim of this study was to assess whether cpp-acp and fluoride could reduce enamel wear rates under erosive conditions simulating abrasion and acidic diet regimen. materials and methods: enamel specimens consisted o...

statement of problem: as a physical property, wear resistance of the materials used in the fabrication of orthodontic retainers play a significant role in the stability and long term use of the appliances. objectives: to evaluate the wear resistance of two commonly used materials for orthodontic retainers: acropars op, i.e. a polymethyl methacrylate based material, and 3a-gs060, i.e. a polyethy...

Abrasive wear behaviour of WC-Co and Fe/Cu-based nanostructured coatings has been investigated under dry slurry conditions in this study. The retention coating constituents was confirmed together with the formation various metallic ceramic phases. rate one order lower than that micro-structured both conditions. Relatively higher abrasion resistance such compare to reference material because com...

aa8090 is an extra light and deformable group of lithium containing aluminum alloys which have recently replaced some aerospace aluminum alloys, such as 2000 and 7000 series, due to their higher elastic modulus and lower specific weight. in this study, aa8090 matrix composites containing 3, 6 and 9 vol.% sic were cast using a modified stir casting method. the casting billets were deformed thoug...

the aim of the present study was to investigate the effect of quenching and tempering temperatures on themicrostructure, mechanical properties and the wear characteristics of medium carbon-high chromium wear resistantsteel. in addition, the dominant wear mechanisms were studied. for this purpose, austenitizing and temperingtemperatures were selected in the ranges of 900- 1000 °c and 300- 500 °c...