Thickness Dependence of Optical Transmittance of Transparent Wood: Chemical Modification Effects

Chen, Hui; Baitenov, Adil; Li, Yuanyuan; Vasileva, Elena; Popov, Sergei; Sychugov, Ilya; Yan, Min; Berglund, Lars A.

doi:10.1021/acsami.9b11816

Cited by 81 publications

(66 citation statements)

References 33 publications

(68 reference statements)

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“…The optical transmittance for higher density species is much improved for bleached templates with thiol–ene matrix, compared with bleached templates and PMMA matrix, see Table 1 , although differences in sample thickness limit the comparison. Transmittances for the same thicknesses are therefore recalculated for some PMMA-data (ash and birch), by fitting values for attenuation coefficients, see the procedure by Chen et al 17 For the present bleached template TW from ash and thiol–ene, see Table 1 , the transmittance is 84%, whereas ash/PMMA at the same 1.3 mm thickness is predicted to have 71% transmittance. For the bleached 1.1 mm birch/thiol–ene in Table 1 , the transmittance is 89%, whereas the predicted value for 1.1 mm bleached birch/PMMA is only 72%.…”

Section: Resultsmentioning

confidence: 99%

Transparent Wood Biocomposites by Fast UV-Curing for Reduced Light-Scattering through Wood/Thiol–ene Interface Design

Höglund

Johansson

Sychugov

et al. 2020

ACS Appl. Mater. Interfaces

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Transparent wood (TW) is an interesting polymer biocomposite with potential for buildings and photonics applications. TW materials need to be eco-friendly and readily processed with few defects, for high optical transmittance and low transmission scattering at wide angles (haze). Two wood templates with different lignin-content are impregnated with a new thiol–ene thermoset system. The more eco-friendly bleached wood template results in transparent wood with high optical transmission and much reduced transmission haze, due to strong reduction of interfacial air gaps. Characterization includes template composition, thiol–ene distribution, and polymerization in wood cell wall by EDX and confocal Raman microscopy, also NMR and DSC, tensile testing and FE-SEM fractography for morphology and wood/thiol–ene interface adhesion assessment. The wood template is a true nanocomposite with thiol–ene polymer located inside the nanoporous wood cell wall. Advanced TW applications require not only appropriate wood template modification and careful polymer matrix selection but also tailoring of the process to impregnation and polymerization mechanisms, in order to reduce optical defects.

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Section: Resultsmentioning

confidence: 99%

Transparent Wood Biocomposites by Fast UV-Curing for Reduced Light-Scattering through Wood/Thiol–ene Interface Design

Höglund

Johansson

Sychugov

et al. 2020

ACS Appl. Mater. Interfaces

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“…Spectral light transmittances (T%) of each group as a function of the wavelength are shown in Figure 2 a. The attenuation coefficients (μ) as a function of the wavelength were also determined [ 47 ], which are shown in Figure 2 b. The attenuation coefficients decreased as the wavelength increased.…”

Section: Resultsmentioning

confidence: 99%

Optical and Mechanical Properties of Highly Translucent Dental Zirconia

Kim

2020

Materials

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The aim was to evaluate the translucency, opalescence, and fluorescence of highly translucent zirconia, lithium disilicate, and bovine teeth. One mm-thick specimens of five monolithic zirconia systems, two glass-ceramics, and bovine enamel/dentin were investigated. A spectrophotometer (Ci7600) was used to measure the CIELab color coordinates, and the translucency and opalescence values were obtained. For evaluating the fluorescence emission, the differences in spectral reflectance by the UV component of illumination were calculated. The microstructures of ceramic specimens were examined with a scanning electron microscope and the chemical compositions were determined with an X-ray fluorescence spectrometer. Mechanical properties were appraised with three-point bending strength, indentation fracture toughness, and Vickers hardness. Data were analyzed using a one-way ANOVA, followed by Tukey’s multiple comparison test (α = 0.05). A higher yttria content (5 mol%) significantly improved the translucency of zirconia ceramics, while they were less translucent than lithium disilicate (p < 0.05). Lowering the alumina content below 0.05 wt.% enhanced the translucency (p < 0.05), but a small amount of alumina was still required to obtain full densification. 0.05 wt.% Fe was used to increase the chroma of zirconia specimens without compromising their mechanical properties. The Er-containing zirconia specimen showed a maximal fluorescence emission at 430 nm. The degree of opalescence was affected by the microstructures of ceramic materials. The microstructure, incorporation of a secondary phase, and sintering behavior can have a strong impact on the final mechanical and optical properties of dental ceramics. Addition of small amounts of metal oxides can affect the translucency, opalescence or fluorescence qualities of zirconia

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“…The relationship of the total optical transmittance and thickness for a scattering and absorbing media should follow an exponential relationship, in which an attenuation coefficient replaces the absorption coefficient of the Beer-Lambert law for non-scattering media. It is based on integrating the time- dependent photon diffusion equation often used to model light penetration into scattering media (Chen et al, 2019). To calculate the attenuation coefficient from the total transmission, we need the actual thickness of each layer.…”

Section: Resultsmentioning

confidence: 99%

Principles and Practice of SARS-CoV-2 Decontamination of N95 Masks with UV-C

Huber

Goldman

Epstein

et al. 2020

Preprint

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A mainstay of personal protective equipment (PPE) during the COVID-19 pandemic is the N95 filtering facepiece respirator. N95 respirators are commonly used to protect healthcare workers from respiratory pathogens, including the novel coronavirus SARS-CoV-2, and are increasingly employed by other frontline workers and the general public. Under routine circumstances, these masks are disposable, single-use items, but extended use and reuse practices have been broadly enacted to alleviate critical supply shortages during the COVID-19 pandemic. While extended-time single use presents a low risk of pathogen transfer, repeated donning and doffing of potentially contaminated masks presents increased risk of pathogen transfer. Therefore, efficient and safe decontamination methods for N95 masks are needed to reduce the risk of reuse and mitigate local supply shortages. Here we review the available literature concerning use of germicidal ultraviolet-C (UV-C) light to decontaminate N95 masks. We propose a practical method for repeated point-of-use decontamination, using commercially-available UV-C crosslinker boxes from molecular biology laboratories or a simple low-cost, custom-designed and fabricated device to expose each side of the mask to 800-1200 mJ/cm2 of UV-C. We measure the dose that penetrated to the interior of the respirators and model the potential germicidal action on SARS-CoV-2. Our experimental results, in combination with modeled data, suggest that a two-minute UV-C treatment cycle should induce a >3-log-order reduction in viral bioburden on the surface of the respirators, and a 2-log order reduction throughout the interior. The resulting exposure is 100-fold less than the dose expected to damage the masks, facilitating repeated decontamination. As such, UV-C germicidal irradiation (UVGI) is a practical strategy for small-scale point-of-use decontamination of N95s.

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Thickness Dependence of Optical Transmittance of Transparent Wood: Chemical Modification Effects

Cited by 81 publications

References 33 publications

Transparent Wood Biocomposites by Fast UV-Curing for Reduced Light-Scattering through Wood/Thiol–ene Interface Design

Transparent Wood Biocomposites by Fast UV-Curing for Reduced Light-Scattering through Wood/Thiol–ene Interface Design

Optical and Mechanical Properties of Highly Translucent Dental Zirconia

Principles and Practice of SARS-CoV-2 Decontamination of N95 Masks with UV-C

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