Glazed Surfaces Research Articles

Evaluation of Numerical Methods for Predicting the Energy Performance of Windows

Windows are important structural components that determine the energy efficiency of buildings. A significant parameter in windows technology is the overall heat transfer coefficient, U. This paper analyzes the methods of numerical determination of the U-value, including for windows that use passive technologies to improve thermal performance. The analysis was intended to evaluate the heat flux and temperature distribution across glazed surfaces and the accuracy of traditional approaches to the determination of heat loss through window structures. The results were obtained using the heat flux measurement method described in the international standard ISO 9869-1:2014. The paper shows that the non-uniformity of the heat flux density on a window surface can be as high as 60%, which in turn generates an error in the calculations based on stationary heat transfer conditions.

Megadunes in Antarctica: migration and characterization from remote and in situ observations

Abstract. Megadunes are peculiar features formed by the interaction between the atmosphere and cryosphere and are known to be present only on the East Antarctic Plateau and other planets (Mars and Pluto). In this study, we have analysed the glaciological dynamic of megadunes, their spectral properties and morphology on two sample areas of the East Antarctic Plateau where in the past international field activities were carried out (EAIIST, East Antarctic International Ice Sheet Traverse; It-ITASE, Italian International Trans-Antarctic Scientific Expedition). Using satellite images spanning 7 years, we analysed the spatial and temporal variability in megadune surface characteristics, i.e. near-infrared (NIR) albedo, thermal brightness temperature (BT) and slope along the prevailing wind direction (SPWD), useful for mapping them. These parameters allowed us to characterize and perform an automated detection of the glazed surfaces, and we determined the influence of the SPWD by evaluating different combinations of these parameters. The inclusion of the SPWD significantly increased the accuracy of the method, doubling it in certain analysed scenes. Using remote and field observations, for the first time we surveyed all the components of upwind migration (absolute, sedimentological and ice flow), finding an absolute value of about 10 m a−1. The analysis shows that the migration is driven by the snow accumulation on the crest and trough prograding upwind on the previous windward flanks characterized by glazed surface. Our results present significant implications for the surface mass balance estimation, paleo-climate reconstruction using ice cores, and the measurements using optical and radar images/data in the megadune areas.

The Effect of Polishing, Glazing, and Aging on Optical Characteristics of Multi-Layered Dental Zirconia with Different Degrees of Translucency.

(1) Background: Considering that the appearance of a dental material is an important factor that contributes to the success of prosthetic restorations. The purpose of this study is to investigate the optical properties and color changes among the layers of three commercial zirconias, to compare the aspect of the polished and glazed surfaces before and after aging and to evaluate the effects of hydrothermal degradation on their aesthetics. (2) Methods: Forty-eight plate-shaped samples were sectioned from presintered blocks of each multilayer translucent zirconia with different Yttrium content: Ceramill Zolid fx ML (5 mol%) = CeZ, STML (4 mol%) = STM, IPS e.maxZirCAD CEREC/in Lab MT Multi (4 mol% + 5 mol%) = IPZ. The samples were sintered according to the recommendation of each manufacturer, and half (24) of them were polished and the other half (24) glazed on one of the surfaces. Each type was equally divided into one control and one aging group, and, for each material, this resulted in four groups (n = 12): polished-control, polished-autoclaved glazed-control, and glazed-autoclaved. The artificial aging was carried out with an autoclave and distilled water at 134 °C, 0.2 MPa for 1 h, and for optical parameters (TP, CR, OP) and color change (ΔE*) measurements on a black and white background in a CIE L*a*b* color system, a spectrophotometer was used. The specimens were evaluated in incisal, cervical, and medium areas on polished and glazed samples before and after the aging stage. Statistical analysis was achieved with a two-way ANOVA test, the unpaired t-test, and the paired t-test. (3) Results: Before and after aging, the mean TP values for polished samples were higher than the glazed ones. After aging, the mean TP values increased for all groups (except polished CeZ), and significant differences were reported for polished STM, IPZ. After LTD, the opalescence registered an increase for almost all groups (except polished CeZ, polished and glazed IPZ-medium area), and significant differences were reported for almost all groups (except STM-incisal, IPZ-cervical, medium areas). The levels of color change were between extremely slight to perceivable. (4) Conclusions: Optical properties of the selected multilayer zirconia were influenced by polishing and glazing as surface treatment and affected by artificial aging (CeZ the least); perceivable color changes for polished STM, IPZ were detected.

TO THE DEFINITION OF CRITICAL MICROCLIMATE CONDITIONS IN PREMISES DURING DISRUPTIONS HEAT SUPPLY SYSTEMS

These days in Ukraine one of the relevant tasks is to maintain the microclimate conditions indoors. Atthe same time, the state of war and the extreme conditions emergence related to the failure of heat supply systems leadto occurrence of critical microclimate conditions. It is known that the enclosing structures of the building includeexternal − walls, windows, other glazed surfaces, coverings of various types and floors, as well as − internal structures,that is, partitions and internal load-bearing walls, floors based on inter-floor ceilings, etc. These enclosing structureshave their influence on the distribution and fluctuations of temperatures in heated rooms. This effect may depend on theroom location in the building perimeter, the size of the room, etc. Modern prefab and block buildings of massconstruction, built according to typical projects, differ from traditional ones in that they have a smaller mass of wallstructures and a larger area of glazing of external enclosures, which has reduced their heat resistance [1−3]. Therefore,determining the critical conditions of the indoor microclimate during disruptions of the heat supply system is a relevanttask. The purpose of the article. Analysis and substantiation of decisions to ensure the required level of reliability andefficiency for elements of the building's heat supply complex from the standpoint of guaranteed support for necessaryinternal thermal conditions during disruptions of the heat supply. Conclusions. 1. Considering the disconnection of theheat supply, the critical conditions for the microclimate in the residential premises are determined. 2. Modelling theindoor climate, taking into account constructive and planning decisions and changes in temperature depending on theseason, allows to predict the adoption of precautionary measures for the equipment operation in buildings and to keepengineering communications in working condition [4−6].

Procena upotrebe otpada pri sečenju bazalta u bojenju različitih kompozicija keramičkih glazura

Color effects in ceramic glazes play a decisive role in the aesthetic and attractiveness of ceramic pieces. The colorants used in glazes interact with the ceramic materials during the firing process, resulting in a wide range of fascinating colors and effects. Due to the natural properties of basalt such as high compressive strength and wear resistance, this natural volcanic rock is attracting a lot of attention when used in ceramic production processes. The aim of this study is to evaluate the effects of basalt cutting waste (BCW) obtained from a stone company in Kayseri, Turkey, on the color effect of ceramic glazes in combination with different frits. For this purpose, glazes were prepared in which BCW was incorporated in different weight percentages of 0-20 % together with different frits. The glazes were characterized by analyzing chemical, phase, and thermal behavior of BCW using X-ray fluorescence (XRF), X-ray diffraction (XRD), and thermal microscopy, respectively. The prepared glazes were then applied to engobed wall tiles and fired at a temperature of 1,200 °C in a laboratory furnace. After firing, the glazed surfaces were subjected to color analysis, while the phase composition was analyzed by XRD. The microstructure analysis was carried out using electron microscopy (SEM/EDS). Increasing the proportion of BCW in the glaze compositions resulted in a change of the color of the finished surfaces from cream to yellow-beige tones. This study sheds light on the potential use of BCW as a coloring agent in the production of ceramic glazes.

Characterization and energy performance of flexible photochromic window films

Windows are considered the weakest components in the building envelope, driven by their low thermal resistance and static transmittance to solar gains. Consequently, innovative coatings are often proposed to promote energy saving performance of windows. This article investigates several flexible photochromic window films capable of reversibly modulating solar gains based on the abundance of ultraviolet radiation. The peel-and-stick films are applied to the internal glazing surface, making them suitable for window retrofits without interrupting building occupancy. The optical properties of the photochromic films are experimentally characterized at various solar radiation intensities. The results are then used to numerically evaluate the energy-saving potential of the different films for a representative room in a high-rise office building located in Tokyo’s warm climate. The results of the experimental and numerical investigations are discussed to show the potential of photochromic films for window-retrofit applications.

Stable-isotope ratios (δ18O and δD) in a firn core from West Antarctica.

A 22.48 m long ice core (BR-IC-4) was collected in the West Antarctic Ice Sheet (at 83°58'59.4" S, 80°07'01.4" W, 1,295 m above the sea level) during the Austral summer of 2004-2005, as a contribution to the International Trans-Antarctic Expedition program. The isotopic composition (δD and δ18O) of 599 samples, corresponding to the upper 12.98 m of the ice core, was determined by gas source mass spectrometry and cavity ring-down spectroscopy. Relative dating was based on the isotopic ratios and major ions (MS-, Na+, nssSO4 2-) and trace elements (Na, S, Sr) concentrations. The record covers approximately 13 years - from 1990 to 2003. The mean accumulation rate of 0.48 ± 0.09 m water equivalent per year (m eq H2O a1) is relatively high for the geographical area and possibly results from snowdrifting from near areas, as attested by ice glaze surfaces in other sites in the region. The stable isotope δD content varies between -367.90‰ and 256.30‰ (mean -314.42 ± 19.01‰); and δ18O ranges from -44.96‰ to 35.08‰ (mean -39.95 ± 2.05‰). Deuterium excess values (mean 3.70 ± 1.54‰) indicate episodic intense oceanic evaporation and high relative humidity in the moisture sources.

Laboratory modeling of glazed tiles inoculated with deteriorative fungi isolated from Masjed-e Jāmé Isfahan and evaluation of their impacts

The Jāmé Mosque of Isfahan or Masjed-e Jāmé is a historical mosque listed as a World Heritage Site by UNESCO in 2012. Tiles are one of the main materials used in this monument. This study was designed to assay the growth of fungi on the glazed tile and evaluating their alterations in the laboratory. Three fungi, Aspergillus niger and Parengyodontium album from outdoor of monument and Penicillium polonicum from indoor of monument, which were previously isolated, selected for this study. The axenic and mixed culture of the fungi was inoculated on glazed tiles (2.5 × 2.5 cm) with different colors of Mosaic, Anthracite blue and Soft fauna and incubated for 6 months at 28–30 °C. After six months incubation, the biodeterioration patterns were assessed via stereomicroscopy, scanning electron microscopy and colorimetry. The results showed that fungi have the ability to attach, grow and form crystals over the glazed tile surfaces. It seems that the growth pattern was affected by fungal species and color of tile. Modeling experiments can be used to evaluate fungal deterioration and to help prediction of appropriate time of restoration.

Express Assessment Method for Color Characteristics of Cocoa-Containing Food Systems

In the contemporary context, climatic conditions in cocoa bean-producing countries and disrupted logistics chains due to the coronavirus pandemic complicate stable cocoa products supply. The study aimed at developing an express assessment method for color characteristics of cocoa-containing food systems where cocoa powder replaced with brown pigment melanin obtained from buckwheat husks, partially. A man prepared five confectionery glaze prototypes: one based on non-alkalized cocoa powder and four samples containing 3; 5; 7 and 10 % melanin powder as a substitute for cocoa powder. The confectionery glaze based on alkalized cocoa powder served as a comparison sample. To study the glaze color characteristics, the researchers covered white plates with samples, enabled the glaze to harden, and then, took images of the glaze surface using a digital camera in a white box at a color temperature of 6000 K; processed images using image analysis software that provided color coordinates determination of any point of the uploaded image in the RGB model. Then, a man determined the color coordinates in trichromatic XYZ coordinates using a color converter. The results revealed that the confectionery glaze prototype containing 15% non-alkalized cocoa powder and 10% melanin was close to the control sample in terms of color characteristics. The suggested approach advantages are the expensive equipment absence, simplicity and data processing accessibility. The method enables running an objective color assessment of a cocoa-containing product, comparing product samples with each other, and defining color differences. The research results offer the challenges for the color scales development for cocoa-containing foods quality assessment.

Application of adhesive technology to a new type of glazed panel for curtain walls with an integrated frame

The adhesive technology offers several advantages over traditional joints, allowing the assembly of construction elements with a reduced number of components. The use of large glazed surfaces is a distinctive feature of modern architecture and is reflected in the curtain walls. In traditional applications, glazed panels simply transfer the stress to the substructure (frame), not assuming a structural role. This article reports the results of an experimental campaign on a new type of wooden panels for windows and curtain walls (patent application No. 1020000023128 and European patent 3071775) which provides for the structural collaboration between the frame and glass panels using adhesives. This solution (glazed panels adhesively bonded to the wooden frame) adequately responds to the performance requirements of the highest class of resistance to wind load for windows (C5 – UNI EN 12207), limiting the maximum displacement within 1 mm (maximum deflection of the order of 1/1500).

Experimental study of heat transfer characteristics of phase change material–filled glazed windows

The inclusion of phase change material (PCM) in glazing unit is an effective method to reduce energy consumption in building by absorbing a portion of the solar radiation for thermal energy storage while allowing visible light to reach the inside environment for daylighting. This results in reduction in fluctuation of temperature and improved thermal comfort for indoor occupants. There is limited published research, for calculating the heat transfer characteristics of the PCM used in the glazing units, especially under climatic conditions prevailing in India. In this work, the heat transfer characteristics of a PCM-filled double glazing unit were analysed experimentally. The heat transfer performance of the PCM-filled double glazed window unit was experimentally studied and compared with that filled with air, water, and a single glazed window. The experiment was carried out on different days for each window unit to find the temperature of inner and outer surface of glazing and also heat flux through the glazing. The result shows that PCM filled double glazing can minimize the inner surface temperature of the window by four degrees below the outer surface temperature in the morning, compared to air and water-filled double glazed windows. However, air and water-filled glazing are only capable of reducing inner surface temperature by a maximum of two degrees. Thus, a PCM-filled double glazed window can efficiently reduce the inner surface temperature than a single glazed window, air, or water-filled window.

Effect of Different Surface Treatments on the Surface Roughness and Gloss of Resin-Modified CAD/CAM Ceramics

The purpose of this in vitro study is to compare the roughness and gloss of four resin-modified CAD/CAM ceramics after different surface treatments. Forty-eight specimens (1.20 × 12 mm2) were prepared from Lava Ultimate (LU), Vita Enamic (VE), Cerasmart (CS), and Crystal Ultra (CU) CAD/CAM ceramics. The prepared specimens were polished with silicon carbide paper before being roughened with a 30 µm grit diamond bur. Each material was allocated into four groups: control (no treatment), Luster Meisinger polishing (MP), Optiglaze (OG), or Meisinger polishing, followed by a final polishing with Shofu Direct Dia Paste (MP+PP). The roughness and gloss were measured after the surface treatment using a profilometer and gloss meter, respectively. Scanning electron microscopy micrographs were obtained to analyze the surface characteristics. Statistical analysis was performed using a multivariate analysis of variance (MANOVA), one-way ANOVA, and Dunnett’s post hoc test (α = 0.05). The surface treatments significantly affected the surface roughness and gloss of the tested materials (p < 0.05). All the tested resin-modified CAD/CAM ceramics demonstrated a lower surface roughness and higher gloss after glazing using OG, followed by MP+PP and MP. The highest and lowest Ra were presented by the control VE (0.63 ± 0.23 µm) and glazed LU specimens (0.04 ± 0.01 µm), respectively. The highest and lowest GU were presented by the glazed LU (90.48 ± 4.69 GU) and the control VE specimens (23.32 ± 2.41 GU), respectively. After clinical adjustment, finishing, and polishing, the restoration is essential to obtain a restorative surface with lower roughness and the highest gloss. Surface glazing using Optiglaze exhibited the smoothest and glossiest surface of all the tested resin-modified ceramics.

Surface characteristics assessment among layers of different translucent multilayered dental zirconia related to aging

Considering that the surface characteristics and microstructure are relevant factors that may affect the appearance and strength of a material, this study aims to analyse the differences regarding surface roughness and microhardness among layers of three types of dental zirconia: super-high translucent zirconia Ceramill Zolid fx ML (5Y-TZP), super-translucent zirconia STML (4Y-TZP), and IPS e.max ZirCAD CEREC/in Lab MT Multi (4Y + 5Y-TZP), also evaluating the influence of the surface treatment performed by glazing and polishing-before, respectively after aging-by thermocycling. Forty plate-shape specimens were sectioned from the ceramic blocks with a precision disc, polished and sintered according to the manufacturer’s instructions and then, equally divided - the surface of some was finished by polishing and the others by glazing; from each category was formed a control (polished/glazed) group and one subjected to termocycling (polished/glazed) − 30.0000 cycles in a 5˚C and a 55˚C bath with distilled water in a thermocycler, resulting four groups of ten samples, for a material. The assessment of surface roughness (Ra, Rz) was performed with a contact profilometer, with Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM); Vickers hardness (VH) values were recorded with a microhardness tester. The evaluations of the surfaces were achieved in each area: incisal, medium, cervical. For statistical analyses, paired sample t-Test, unpaired sample t-Test, two-way ANOVA test (α = 0.05), Pearson's correlations were used. Both before and after thermocycling, polishing and glazing, as surface treatment have a significant effect on roughness, respectively on microhardness; no statistical differences were observed among areas, on each polished or glazed surface. On the glazed samples, the values recorded for surface roughness were significant higher and for microhardness-lower, compared with those of the polished group. After thermocycling, microrougness increased for STML and all polished specimens and decreased on glazed surfaces of Ceramill Zolid fx ML and IPS e.max ZirCAD CEREC/in Lab MT Multi. Concerning microhardness, the thermocycling procedure had no significant influence. The super-high translucent material was less affected by aging than the super-high translucent zirconia.

Evaluation of biofilm formation on acrylic resins used to fabricate dental temporary restorations with the use of 3D printing technology

BackgroundTemporary implant-retained restorations are required to support function and esthetics of the masticatory system until the final restoration is completed and delivered. Acrylic resins are commonly used in prosthetic dentistry and lately they have been used in three-dimensional (3D) printing technology. Since this technology it is fairly new, the number of studies on their susceptibility to microbial adhesion is low. Restorations placed even for a short period of time may become the reservoir for microorganisms that may affect the peri-implant tissues and trigger inflammation endangering further procedures. The aim of the study was to test the biofilm formation on acrylamide resins used to fabricate temporary restorations in 3D printing technology and to assess if the post-processing impacts microbial adhesion.MethodsDisk-shaped samples were manufactured using the 3D printing technique from three commercially available UV-curable resins consisting of acrylate and methacrylate oligomers with various time and inhibitors of polymerization (NextDent MFH bleach, NextDent 3D Plus, MazicD Temp). The tested samples were raw, polished and glazed. The ability to create biofilm by oral streptococci (S. mutans, S. sanguinis, S. oralis, S. mitis) was tested, as well as species with higher pathogenic potential: Staphylococcus aureus, Staphylococcus epidermidis and Candida albicans. The roughness of the materials was measured by an atomic force microscope. Biofilm formation was assessed after 72 h of incubation by crystal violet staining with absorbance measurement, quantification of viable microorganisms, and imaging with a scanning electron microscope (SEM).ResultsEach tested species formed the biofilm on the samples of all three resins. Post-production processing resulted in reduced roughness parameters and biofilm abundance. Polishing and glazing reduced roughness parameters significantly in the NextDent resin group, while glazing alone caused significant surface smoothing in Mazic Temp. A thin layer of microbial biofilm covered glazed resin surfaces with a small number of microorganisms for all tested strains except S. oralis and S. epidermidis, while raw and polished surfaces were covered with a dense biofilm, rich in microorganisms.ConclusionsUV-curing acrylic resins used for fabricating temporary restorations in the 3D technology are the interim solution, but are susceptible to adhesion and biofilm formation by oral streptococci, staphylococci and Candida. Post-processing and particularly glazing process significantly reduce bacterial biofilm formation and the risk of failure of final restoration.

Nano technology building insulation effect on the thermal behavior of building under different Algerian weather

The energy consumption of the building sector in Algeria represents the largest part of the energy produced in the country. Action to reduce the impact of this sector on the economy and the environment must be taken. The use of thermal insulation to reduce the energy needs of the building sector represents an effective and sustainable solution. The objective of our work is to conduct a study using the TRNSYS 17 software on the influence of the use of thermal insulation in different climates in Algeria. A typical apartment is chosen to run the calculations under three different climates of Algeria. The simulation results obtained for the city of Annaba show that the use of rock wool, cork, expanded polystyrene and airgel insulation allows a reduction of 42.81%, 43.08%, 43.31% and 50.90% respectively. While for the city of Setif the reduction obtained is 34.15%, 34.70%, 35.13% and 52.25% respectively for the same insulation. For the city of Biskra the reduction is 32.07%, 32.28%, 32.45% and 38.72% respectively for the same insulation. The improvement of the thermal performance of the structure and the glazed surfaces according to the Passivhaus standard allows a significant reduction of heating and air conditioning needs estimated at 72, 78.21 and 65.21% respectively for the cities of Annaba, Setif and Biskra. A low energy consumption building is obtained for the city of Annaba and Setif.

Numerical investigation of fire in the cavity of naturally ventilated double skin façade with venetian blinds

Double skin façades (DSFs), offer great views, architectural aesthetics, and energy savings. Yet, in a fire event the glass façade breaks leading to risks to human life and firefighting difficulties. Shading devices incorporated to prevent unfavourable heat gains to reduce cooling load though offer energy savings potentially present other challenges in firefighting and occupants’ evacuation. In this study, Fire Dynamic Simulator (FDS) was used to numerically investigate the spread of a 5 MW HRR polyurethane GM27 fire in a multi-storey double skin façade building with Venetian blinds placed in its cavity. The blinds were positioned 0.4 m away from the internal glazing, middle of the cavity and 0.4 m away from the external glazing respectively. In each blind position the slat angle was opened at 0°, 45°, 90° and 135° respectively. The results show peak inner glazing surface temperature ranged between 283°C to 840°C depending on the thermocouple position, the Venetian blind position and slat opening angle. Without Venetian blinds, peak inner glazing surface temperatures ranged between 468°C to 614°C. In all cases except when the slat angle was 0° and the blind was positioned closer to the outer glazing, the inner glazing surface temperature from the closest thermocouple (TC 14) above the fire room exceeded 600°C, the glass breakage temperature threshold. Overall, the Venetian blind position and slat opening angle influenced the spread of fire. Venetian blind combustibility and flammability were not considered and therefore recommended for future studies. Practical Application: Our manuscript helps to develop new thinking on mitigation of fire risks in buildings for architects, engineers and designers when incorporating Venetian blinds in Double Skin Façades (DSFs).

Green-blue infrastructure in the built environment – sustainable and resource-saving designs for urban structures and open spaces

Urban grey infrastructure, as it generally consists of monofunctional, sealed, impervious, heating up and reflecting surfaces, has led to a series of serious challenges (urban heat stresses, loss of biodiversity, flood risks and natural hazards) decreasing urban resilience. Ongoing construction activities result in irreversible soil consumption and loss of its numerous and vital functions. However, a common understanding has been evolving that the establishment of green-blue infrastructure (GBI) supports compensating for functional losses, as they are integrative and provide pervious, absorbent, shading and non-heating up surfaces. We present a concept to holistically interconnect stand-alone approaches to improve and support constructional design for transforming green open spaces addressing specifically urban landscape construction and building greenery. The underlying state of knowledge emerges from currently four ongoing projects on advancing GBI for re-establishing ecosystem functions and diverse habitats: 1. The Circular Soil Concept targets the reuse of excavated soil materials from construction sites to produce engineered soils. These are applied as functional vegetation substrates for landscape construction and installing building greenery, saving scarce soil resources while generating large scale and vegetated areas with climate change adaptation performance. 2. The StreetTREE-Planter is designed to install urban trees in a given street infrastructure. The advanced planter systems will support extended tree lifespans, microclimatic benefits, flood protection and urban resilience. The design is based on targeted rainwater harvesting for irrigation management in alignment with water requirements and the desired microclimatic performance. 3. The GLASGrün projects generates plant-based shading designs for glass facades. As plants and their leaves do not heat up from solar radiation, vertical greenery is promising, however challenging, for green shading of glazed surfaces and for indoor and outdoor microclimatic regulation. 4. The INReS rainwater management tool was developed as a prototype web application to integrate sustainable, plant-based rainwater management systems into BIM-(Building Information Modeling)-based construction projects. It provides up-to-date design for the wider public and specific planning guidelines. In synthesis with the present and upcoming findings of these projects, a parameter-based and BIM-compatible GBI-design management tool is foreseen to better and sustainably integrate GBI systems into construction projects, and to consider the resource question.

Optical characterization of historical coloured stained glasses in winter gardens and their modelling in daylight availability simulations

Coloured stained glasses, with their peculiar light transmission properties, affect the perception of indoor spaces especially in winter gardens, where a great amount of coloured glazed surfaces can be easily found. This research aims at advancing the knowledge of coloured stained glasses in architecture and how they can be modelled in daylight simulation software tools. To this aim, the paper first proposes the measurement of light transmittance spectra for a series of coloured glazing tiles installed in a richly decorated Liberty style winter garden in Catania (Southern Italy). The measurements are performed in-place with a portable spectrophotometer, which does not imply dismantling the glazed tiles. A second novelty consists in the identification of the perceived chromaticity for the transmitted daylight, by means of the CIE Colour Space. This analysis reveals that, despite around 75% of the glazed elements are coloured, indoor light is still perceived as colour-neutral because of the wise location of clear panes.Then, the calculated integral transmittance values were used to model the winter garden in the Radiance-based ClimateStudio tool, and the reliability of two different degrees of simplifications in the model was also investigated. The comparison between simulated and measured indoor illuminance values demonstrates that the proposed simplified approach allows very good reliability in daylight modelling, with an average discrepancy below 11%, while also reducing time needed for the preparation of the model. Finally, the validated model is used to assess year-round daylight availability indoors by means of climate based daylight metrics.

Microstructural evolution of amorphous self‐healing geopolymer composites containing alumina and glass frit

AbstractGeopolymer refers to a large group of nanoporous, nanoparticulate materials that are synthesized by dissolution and polycondensation of aluminosilicates in basic solutions and can be made from a variety of starting materials, such as industrial waste ash, volcanic rock, or calcined clay. Geopolymers are X‐ray amorphous, corrosion resistant, refractory, and made at ambient temperature and pressure similar to cements. In this study, potassium metakaolin‐based geopolymer (KGP) composites containing alumina platelets and glass frit were fabricated, and the impact of heating temperature, dwell time, and heating/cooling rate on the microstructure was studied. The composites, heat treated up to 900°C for up to 20 h using heating/cooling rates of up to 1°C/min, showed that the addition of alumina platelets prevented major microcracking and was also able to reduce linear shrinkage. Glass frit has been shown to heal microcracks formed during KGP dehydration and crystallization. The resulting material had an open porosity of less than 1% and a uniform surface glaze of 250 μm thickness, while Oswald ripening of round closed pores occurred due to the migration of molten glass in the system.

Solid-phase synthesis of perovskite using spent SCR catalyst and calcium carbonate and its application as ceramic opacifier

In this study, the synthetic perovskite powder (SPP) was produced by solid-phase method using S-SCR and calcium carbonate (CaCO3), and its structure, morphology, and application as ceramic opacifier were studied. The results show that SPP with a single perovskite phase can be obtained by grinding and calcining raw materials. Adding SPP as opacifier of sanitary ceramics for firing, a white ceramic glaze with excellent opacity was obtained. Among the glaze chromaticity values, L* is 93.09, a* is −0.76 and b* is 4.98. The opacity of the glaze is stronger than that of the glaze using ZrSiO4 and TiO2 as opacifiers, and the whiteness of the glaze is significantly greater than that of glaze with TiO2. The ceramic glaze layer using SPP is mainly composed of glass phase, titanite and quartz, of which titanite is the opacified phase. Importantly, TiO2 is pre-combined into perovskite to make it unable to freely and avoid its own high-temperature phase transition reaction, which is the mechanism to inhibit the yellowing of glaze surface caused by direct use of TiO2. This study can play a positive role in improving the utilization value of S-SCR and eliminating the yellowing of ceramic glazes using TiO2 as opacifier.