Browsing by Subject "roughness"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Abrasive Resistant Coatings—A Review
    (MDPI, 2014-05-21) Wu, Linmin; Guo, Xingye; Zhang, Jing; Mechanical Engineering, School of Engineering and Technology
    Abrasive resistant coatings have been widely used to reduce or eliminate wear, extending the lifetime of products. Abrasive resistant coatings can also be used in certain environments unsuitable for lubrications. Moreover, abrasive resistant coatings have been employed to strengthen mechanical properties, such as hardness and toughness. Given recently rapid development in abrasive resistant coatings, this paper provides a review of major types of abrasive coatings, their wearing mechanisms, preparation methods, and properties.
  • Thumbnail Image
    Item
    Objective and Quantitative Assessment of Caries Lesion Activity
    (Elsevier, 2018) Ando, Masatoshi; Fontana, Margherita; Eckert, George J.; Arthur, Rodrigo A.; Zhang, Hui; Zero, Domenick T.; Cariology, Operative Dentistry and Dental Public Health, School of Dentistry
    Objectives Evaluate the ability of objectively measured specular reflection, roughness, and fluorescence change during dehydration to assess caries lesion activity. Methods One hundred ninety-five ground/polished 3 × 3 × 2 mm sound human enamel specimens were divided into three groups and demineralized using a multispecies microbial caries model for 3, 6, or 9 days; and then remineralized with 1100 ppm-F as NaF solution for 10 days using a pH-cyclic model. Reflection (amplitude: %), roughness (Ra: μm), fluorescence change during dehydration (ΔQ: %×mm2), and microfocus computed tomography [μ-CT: lesion volume (μm3)] were measured for sound, demineralized and remineralized enamel. The surface was hydrated and fluorescence images were acquired at 1 s intervals for 10 s (ΔQ10). During image acquisition, surface was dehydrated with continuous compressed air. Changes-in-ΔQ per second (ΔQD: %×mm2/sec) at 5 (ΔQD5) and 10 s (ΔQD10) were obtained. Results Reflection decreased from sound to demineralized groups (p < 0.0001); remineralized groups were higher than demineralized groups (p < 0.001), but not different from sound (p > 0.32). Roughness increased from sound to demineralized groups (p < 0.0001) and remineralized groups were also higher than sound (p < 0.0001). ΔQ10, ΔQD5 and ΔQD10 increased from sound to demineralized groups (p < 0.0001), and remineralized groups decreased compared to demineralized groups (p < 0.05), but was higher than sound (p < 0.0001). The correlations of μ-CT with reflection, roughness, and ΔQ10 were −0.63, 0.71, and 0.82, respectively (p < 0.0001). Conclusions Reflection, roughness and ΔQ could distinguish between sound and demineralized enamel. Reflection and ΔQ were able to distinguish between demineralized and remineralized enamel. Clinical significance Determination of caries activity, whether a lesion is active or inactive, is an essential and critical component of caries diagnosis. However, especially for enamel lesions, it is difficult to estimate without longitudinal follow-up. Reflection, roughness and fluorescence change during dehydration have the potential to measure caries lesion activity at a-single-appointment.