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Permeability is a normalized term that is calculated based on vapor flow, vapor drive, and saturation pressures. However, it does not take into account the total volume of water vapor that is actually transmitting across a wall assembly at a given temperature and relative humidity. It also does not take into account other factors, which may include chemical diffusion and moisture content concentration. This paper will present water vapor transmission data collected on a variety of air barrier membranes, both permeable and non-permeable, at different temperatures and relative humidity. These data show a variation in permeability as a function of temperature; however, this is not reflected in ASTM E96, Standard Test Methods for Water Vapor Transmission of Materials, Methods A and B, the standardized perm rating often used by professionals to design wall assemblies. Hygrothermal analysis tools primarily use a permeability input based on relative humidity and do not directly consider temperature outside of the general Schirmer equation. This paper will provide an initial look at the implications of this limitation based on the vapor drive data through the use of hygrothermal analysis and wall assembly testing. The aforementioned may have intriguing implications on how we assess materials selected for exterior wall assemblies in construction. These same implications potentially influence how the industry establishes performance metrics and how they may relate to a wall assembly’s actual performance. This paper will serve to initiate a candid discussion on the subject matter.

Melt-quenching method was used to synthesize a series of zinc tellurite glasses doped with erbium oxide and silver oxide. At room temperature, X-ray diffraction (XRD) and density measurement were implemented to characterize the prepared glass samples. The amorphous nature of the glass samples is proven from the XRD spectra obtained in this work. The density of the glass showed an increment trend from 4.4673 to 4.9705 g/cm3 when adding more silver oxide, which can prove that the glass strength is higher. For photoluminescence analysis, blue, green and red emissions were found in the glass series under 375 nm excitation wavelength. According to McCumber theory, higher emission cross-section and higher FWHM are efficient for both broadband amplifier and laser application. More extensive and flatter gain with a maximum gain difference has covered both C and L bands for optical communication, providing a few channels in the wavelength division multiplex network (WDM). The high efficiency of optical amplification is justified with a higher gain figure of merit and larger gain bandwidth. According to McCumber’s theory, all the results proved that 0.03 molar fraction of silver oxide is the most optimum concentration to be applied in the optical application. In Judd-Ofelt analysis, spectroscopic quality factor and shorter lifetime is a crucial parameter for obtaining intense laser transition, strong emission probabilities and encouraging the laser optical transition, which was successfully attained in all glass samples. The present glass system is also applicable for white light application since the standard equal energy point from all glass samples were located near the center of the CIE diagram (0.33, 0.33). In the meantime, higher values of CCT range from 6761 to 6937 K produce light with a better image as compared to lower CCT. Higher CCT is commercially used in LCD (liquid crystal display) and CRT (cathode ray tube) screens. The colour purity is a parameter for better white LED application, whereas low colour purity is for pure white light emission. Therefore, lower colour purity was found around 10.7 around 18.8% in all glass samples.

Green building practices, net-zero targets for buildings, and new energy codes for buildings around the world are creating demands for high-performance thermal insulation materials. Aerogel blanket is a high-performance thermal insulation having thermal resistance two to three times higher than traditional thermal insulation materials. Aerogel in blanket form is an extremely convenient material for building envelope constructions and can be cut to any reasonable size or shape. The blanket is usually available in a 10-mm thickness and can be applied, if necessary, in multiple layers. This paper assesses the implications of added aerogel thermal insulation in three different wall systems (commercial, residential, and heritage) on their moisture management performance. The hygrothermal simulation tool WUFI® Pro 5.3 was used to carry out more than 50 simulations in five different locations (Wilmington, NC; Vancouver, BC; Minneapolis, MN; Chicago, IL; and Baltimore, MD) in North America. Simulation results demonstrate that appropriate design and construction techniques can successfully integrate aerogel blanket insulation in energy-efficient commercial, residential, and heritage wall constrictions without compromising long-term performance or durability caused by poor moisture management.