Since the outbreak of COVID-19, wearing a mask, voluntary or obligatory, has led to diverse and numerous designs. Guidelines for minimum requirements include tests for visual inspection, strength, filtration, and breathing resistance, but not for the fit of a mask. The fit of a mask was assessed by testing the outward leakage of exhaled breath based on the visualization of coloured mist exhaled by a manikin head. Fourteen masks were selected based on differences in design, such as type of material, shape (cheek wings vs. none), filter type, and the number of layers. Leakage expressed in mean mist percentages (visualized with a camera), patterns of coloured mist left inside the masks, as well as visual fit of the masks on the manikin head, showed that a loose fit mask results in more leakage. Also, combining quantitative with qualitative assessment proved to be complementary. Future tests should be conducted on a range of users, covering the best fit over time as well breathability, use, and comfort. The use of face masks, whatever their characteristics, seem an adequate strategy to reduce the dispersion of potential ‘infected’ aerosols into the space from people, as opposed to not wearing one. ... Read more

3D-printing has transformed traditional manufacturing by enabling the fabrication of individually designed complex systems. The building’s façade is one of the most challenging systems because it affects the control of the built indoor environment and allows to provide energy-saving.
The objective of this research is to distinguish 3D-printing technologies and applied materials in them that improve transparency in the façade to decrease artificial lighting consumption, to control solar energy, and to improve energy-savings.
A literature study was performed, firstly, different 3D-printing techniques and their materials for producing transparent outcomes were reviewed from academic databases. Then, transparent 3D-printed façade prototypes were identified.
The outcomes indicated that most of the prototypes used the FDM 3D-printing technique and Polyethylene Terephthalate Glycol as a material. These prototypes didn’t consider the disadvantages of the FDM technique for the lighting transmission. Additionally, some prototypes have control over daylighting discomforts but some of them not. Prototypes tried to improve energy-saving which ranged from applying recyclable materials to controlling solar gain. ... Read more