Mira3 xmu field emission scanning electron microscope sem

For the visualization of microstructures, as well as the fungal mycelia and spores on NF mats and NF-PP mats, before (t₀) and after (t₂₈) physical/mechanical testing, a Tescan Mira3 XMU Field Emission Scanning Electron Microscope/SEM (Tescan, Kohoutovice, Česká republika) was employed. Fungal colonies grown on the water-fungi group were also identified using a standard optical microscope.

Batch 2 specimens were randomly divided into two groups for (a) physical property testing: (dry control; n = 5), (wet control; n = 5), (samples with varying ranges of % growth coverage; n = 25), and (b) mechanical property testing (dry control; n = 5), (wet control; n = 5), and (samples with varying ranges of % growth coverage; n = 21). Group (a) specimens were drained of excess water and placed in an oven at 50°C for one week to measure their dry weights. For tensile testing (group (b)), the gypsum boards were air-dried, the paper backing was separated, and cut in half vertically. The tensile tests were performed using the Instron 5969 machine and the strength property of material samples was measured under a modified ASTM D828-97 standard. The modification included the removal of the paper backing from the gypsum (containing less fungal growth) prior to tensile testing and cutting the samples vertically in two in order to prevent the gypsum from dominating the paper tensile strength. For microstructural visualization purposes, selected gypsum board papers with varying ranges of % growth coverage (n = 10), as well as dry (n = 3) and wet controls (n = 3), were tested using a Tescan Mira3 XMU Field Emission Scanning Electron Microscope/SEM (Tescan, Kohoutovice, Czech Republic) on fractured surfaces.