The siliceous structure that protects diatoms, called frustule, is the main component of diatom sedimentary soils. These particles' physical and mechanical characteristics are challenging, given their geometric conditions of only a few microns. For this evaluation, specialized tools must be used, such as the Scanning Electron Microscope (SEM), the Atomic Force Microscope (AFM) and X-ray dispersion (XRD), among others. The bibliographic references show significant variability in the load-deformation behavior in frustules, diatoms or their organic components. Technical background information usually presents information on a single type of species. This research demonstrated the characterization and micromechanical evaluation of frustules of three morphologically distinguishable species of diatoms (Colombian, Mexican and Peruvian origin). The results showed similarities in the chemical composition of the three samples. The displacement records are variable depending on the species for the same load range. The location of the load application points by AFM on the different types of frustules is presented. The most significant deformation in the Mexican species and the regularity in the results of the Peruvian species stand out. Young's moduli were also calculated by applying the Hertz Model, which had the highest values in the Colombian sample.

External contamination (soiling) of the incident surface is a major limiting factor for solar technologies. A 5year field glass coupon study was conducted to better understand external contamination and its effects; compare cleaning methods and the use of preventative coatings; and explore the abrasion resulting from cleaning to advise on accelerated abrasion testing. Test sites included the cities of Dubai (UAE), Kuwait City (Kuwait), Mesa (AZ), Mumbai (India), and Sacramento (CA). Through the 5-year cumulative study, dry brush, water spray, and wet sponge and squeegee cleaning methods were compared to no cleaning. Optical microscopy was used to obtain images, including representative color images, grayscale images for object analysis, and oblique images for coating integrity assessment. A thresholding protocol was developed to analyze and distinguish specimens using the ImageJ software. Optical performance was quantified using a spectrophotometer, including comprehensive optical characterization (transmittance, reflectance, and absorptance in addition to forward- and back- scattering). Atomic force microscopy was used to verify the abrasion damage morphology, including the width and depth of surface scratches. Analysis of the results included correlation of optical performance and particle area coverage, rank order (by coating or location), and the acceleration factor for abrasion damage. The efficacy of external cleaning was more readily distinguished from the effectiveness of antisoiling coatings. The acceleration factor for dry brush cleaning of a porous silica coating was found to be on the order of unity.