Experimental Verification of Theoretical Ageing and Service Life Prediction Model for Vacuum Insulation Panels

Vacuum Insulation Panels (VIPs) are a kind of the super-insulated materials (SIMs). VIPs are innovative material in various fields like the building sector as it encompasses a higher thermal resistance per unit of thickness compared to conventional insulation. To extensively use VIPs in the building sector, comprehensive performance analysis, and their properties such as thermal conductivity valuations are required to be done under simulated conditions to evaluate its longterm performance. However, different VIPs have varying durability, and as it stands, there is no comprehensive understanding of how all VIPs will behave in real conditions. This research investigates the effect of multiple variables (such as temperature, relative humidity) on VIP service life. The purpose of this research is to validate the theoretical ageing model of VIPs. First, the experimental thermal conductivity results from seven samples of three different VIP categories are collected using a heat flow meter. To measure the accelerated ageing results over 25 years, Arrhenius equation is applied. Next, NRC theoretical model is used to predict the ageing response of the samples. Finally, an analytical method is employed to verify and validate this model based on the collected data. Results shows that effect of ageing and environmental temperature have higher impacts on the performance of fibreglass panels than the fumed silicas. Additionally, the aging effects analysis reveals that microporous silica VIP products would maintain their superior thermal performance over time. Keywords: Vacuum insulation panel, Ageing, Thermal conductivity, accelerated ageing, modelling

Experimental Verification of Theoretical Ageing and Service Life Prediction Model for Vacuum Insulation Panels

Vacuum Insulation Panels (VIPs) are a kind of the super-insulated materials (SIMs). VIPs are innovative material in various fields like the building sector as it encompasses a higher thermal resistance per unit of thickness compared to conventional insulation. To extensively use VIPs in the building sector, comprehensive performance analysis, and their properties such as thermal conductivity valuations are required to be done under simulated conditions to evaluate its longterm performance. However, different VIPs have varying durability, and as it stands, there is no comprehensive understanding of how all VIPs will behave in real conditions. This research investigates the effect of multiple variables (such as temperature, relative humidity) on VIP service life. The purpose of this research is to validate the theoretical ageing model of VIPs. First, the experimental thermal conductivity results from seven samples of three different VIP categories are collected using a heat flow meter. To measure the accelerated ageing results over 25 years, Arrhenius equation is applied. Next, NRC theoretical model is used to predict the ageing response of the samples. Finally, an analytical method is employed to verify and validate this model based on the collected data. Results shows that effect of ageing and environmental temperature have higher impacts on the performance of fibreglass panels than the fumed silicas. Additionally, the aging effects analysis reveals that microporous silica VIP products would maintain their superior thermal performance over time. Keywords: Vacuum insulation panel, Ageing, Thermal conductivity, accelerated ageing, modelling

Correction: Correction: Multi-scale microporous silica microcapsules from gas-in water-in oil emulsions

Correction for ‘Correction: Multi-scale microporous silica microcapsules from gas-in water-in oil emulsions’ by Zenon Toprakcioglu et al., Soft Matter, 2020, 16, 3586–3586, DOI: 10.1039/D0SM90059A.

Assessing the protective effects of different surface coatings on NaYF4:Yb3+, Er3+ upconverting nanoparticles in buffer and DMEM

We studied the dissolution behavior of β NaYF4:Yb(20%), Er(2%) UCNP of two different sizes in biologically relevant media i.e., water (neutral pH), phosphate buffered saline (PBS), and Dulbecco’s modified Eagle medium (DMEM) at different temperatures and particle concentrations. Special emphasis was dedicated to assess the influence of different surface functionalizations, particularly the potential of mesoporous and microporous silica shells of different thicknesses for UCNP stabilization and protection. Dissolution was quantified electrochemically using a fluoride ion selective electrode (ISE) and by inductively coupled plasma optical emission spectrometry (ICP OES). In addition, dissolution was monitored fluorometrically. These experiments revealed that a thick microporous silica shell drastically decreased dissolution. Our results also underline the critical influence of the chemical composition of the aqueous environment on UCNP dissolution. In DMEM, we observed the formation of a layer of adsorbed molecules on the UCNP surface that protected the UCNP from dissolution and enhanced their fluorescence. Examination of this layer by X-ray photoelectron spectroscopy (XPS) and mass spectrometry (MS) suggested that mainly phenylalanine, lysine, and glucose are adsorbed from DMEM. These findings should be considered in the future for cellular toxicity studies with UCNP and other nanoparticles and the design of new biocompatible surface coatings.