The technology of polychrome glazed ceramics in Ifriqiya: new data from the site of Chimtou.

Ifriqiya (roughly Tunisia and eastern Algeria) is believed to have played a significant role in the diffusion of ceramic glazed technologies into other regions of the Western Mediterranean. However, due to limited analysis on North African glazed ceramics, its role in technology transfer remains poorly understood. This paper uses SEM-EDS and petrographic analyses to understand the technology employed in the production of Tunisian ceramics through the study of 30 polychrome glazed ceramics from a medieval settlement at the site of Chimtou (ancient Simitthus), Tunisia, dated to the late ninth-twelfth century. The results show that these are lead-rich glazes with varying contents of alkalis, coloured with copper, iron and manganese oxide and applied over a calcareous body. Opaque glazes were obtained using cassiterite crystals as opacifier or by adding crushed quartz. The use of lead stannate as a colourant and opacifier in one light yellow glaze raises questions about the mechanisms of introduction of tin opacification technology in North Africa. Scrap metal seems to have been used as a source of lead for the glazes; while iron slag was probably used as a source of iron to colour the glaze in one sample, pointing to a cross-craft interaction between glazemaking and metallurgy. Supplementary information: The online version contains supplementary material available at 10.1007/s12520-024-01974-x.

Effect of toothbrushing on surface roughness, gloss, and topography of polished and glazed ultra-translucent zirconia.

PURPOSE: This study evaluated the effect of toothbrushing cycles on surface roughness (Ra), gloss (GU), and morphology of two zirconia finishing and polishing protocols. MATERIALS AND METHODS: An ultra-translucent zirconia disc was sectioned into rectangular plates (12 mm × 7 mm × 3 mm) and divided into two groups according to the polishing and finishing system used (diamond rubber abrasive/DRA or glazing/GLA). Bovine enamel (BEN) plates with the same dimensions were used as a Control. Specimens of zirconia and enamel were analyzed for Ra and GU (n = 11) and surface morphology by scanning electron microscopy (n = 3) before toothbrushing (baseline) and after 15,000 and 30,000 toothbrushing cycles. Ra and GU data were analyzed by ANOVA two-way and post-hoc Tukey's test (α = 0.05), while the surface morphology was analyzed qualitatively. RESULTS: The Ra decreased significantly after 30,000 toothbrushing cycles for DRA and GLA zirconia ceramics. DRA showed a higher GU at the baseline, after 15,000 and 30,000 toothbrushing cycles than GLA and BEN. Toothbrushing polished the zirconia, creating a smooth surface, while no changes were observed for BEN. CONCLUSIONS: The increase in toothbrushing cycles (30,000) changed the surface roughness of DRA and GLA zirconia ceramics. DRA zirconia presented the highest GU, which did not change with toothbrushing.

Preparation and Application of Apatite-TiO2 Composite Opacifier: Preventing Titanium Glaze Yellowing through Pre-Combination.

In order to enhance the degree of binding reaction of TiO2 in titanium-containing ceramic glazes and prevent the reaction of its transformation into rutile to eliminate the yellowing phenomenon of the glaze surface, an apatite-TiO2 composite opacifier (ATO) was prepared through the mechanical grinding of hydroxyapatite and anatase TiO2. The properties, opacification mechanism, and yellowing inhibition of the prepared ceramic glazes were studied. The results show that the ATO is characterized by a uniform coating of TiO2 on the surface of the apatite and the formation of close chemical bonding between the apatite and TiO2. The ceramic glaze surface when using an ATO has a white appearance and excellent opacification performance. When an ATO was used, the L*, a*, and b* values of the glaze were 89.99, -0.85, and 3.37, respectively, which were comparable to those of a ZrSiO4 glaze (L*, a*, and b* were 88.24, -0.02, and 2.29, respectively). The opacification of the glaze was slightly lower than that of the TiO2 glaze (L* value was 92.13), but the appearance changed from yellow to the white of the TiO2 glaze (b* value was 9.18). The ceramic glaze layer when using an ATO mainly consists of titanite, glass phase, and a small amount of quartz, and the opacification mechanism is the crystallization of the generated titanite. ATOs can play an active role in solving the critical problem that arises when TiO2 replaces ZrSiO4 as an opacifier.

Effect of zirconia surface conditioning before glazing on the wear of opposing enamel: an in vitro study.

OBJECTIVES: This in vitro study aimed to evaluate the wear of natural teeth opposing 3 mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) with different surface conditions. MATERIALS AND METHODS: Sixty 3Y-TZP specimens were randomly assigned to six groups (n = 10), differing in surface condition. In three groups, the samples underwent glazing-with the glaze applied to roughened (i.e., 106-µm-grit diamond-finished), as-sintered, and polished zirconia. The three remaining groups consisted of unglazed specimens: solely polished samples and diamond-finished samples (106-µm-grit and 46-µm-grit) without further conditioning. Two-body wear was evaluated at extracted, non-carious molars (n = 60), which served as antagonists in chewing simulation (10,000 masticatory cycles, 49N load). As a control, natural teeth with intact enamel surfaces were tested against natural molars (n = 10). All samples were 3D-scanned before and after the chewing simulation (7 Series, Straumann). Volume loss was calculated (Inspect Software, GOM), and statistically analyzed (SPSS Statistics 24, IBM). RESULTS: Volume loss of the natural antagonists decreased in the following order: 106-µm-grit diamond-finished zirconia (4.6 ± 2.5 mm3), glazed 106-µm-grit diamond-finished zirconia (3.8 ± 1.1 mm3), glazed as-sintered zirconia (3.5 ± 0.9 mm3), 46-µm-grit diamond-finished zirconia (1.7 ± 0.6 mm3), control (1.6 ± 0.7 mm3), glazed polished zirconia (1.4 ± 0.5 mm3), and solely polishing (0.4 ± 0.2 mm3). Even when polishing the surfaces before glazing, volume loss was not mitigated to the same extent as after polishing alone. CONCLUSIONS: The zirconia surface condition beneath the glazing influences antagonist wear. Although polishing before glazing resulted in acceptable levels of antagonist wear, this approach did not yield as favorable results as polishing alone. CLINICAL RELEVANCE: For operators favoring glazing, pre-polishing the zirconia surface could be advantageous to reduce wear.

Influence of different surface finishing procedures of strength-gradient multilayered zirconia crowns on two-body wear and fracture load: Lithium silicate or leucite glazing versus polishing?

OBJECTIVES: To examine the influence of different finishing procedures on the surface roughness, wear resistance and fracture load of strength-gradient multilayered zirconia. MATERIALS AND METHODS: Zirconia crowns (Multilayer 3D pro; n = 96) were manufactured and treated with a lithium-silicate- (LISI_S), leucite-based glaze spray (LEU_S), leucite-based glaze mass (LEU_M) or polished (POL). Natural molars (CG; n = 24) acted as a control. Roughness was determined on flat glazed specimens (n = 28). Two-body wear was examined by digitalizing and matching the occlusal surface before and after thermo-mechanical aging (6,000 thermal and 1,200,000 chewing cycles). The groups were split to measure fracture load initially and after aging. Kolmogorov-Smirnov, Spearman correlation, Kruskal-Wallis-H, Levene's test, one-way ANOVA with Scheffé post-hoc and Weibull modulus were computed. RESULTS: POL presented the lowest and LEU_S the highest roughness. Following POL, no ceramic loss was observed. LISI_S, LEU_S and LEU_M showed lower ceramic wear than the CG. The lowest wear of the antagonist was observed for the CG. LISI_S showed a lower antagonistic wear than LEU_S, LEU_M and POL. LISI_S, LEU_S, LEU_M and POL showed higher fracture load values and Weibull moduli than the CG. Artificial aging did not impact the fracture load or Weibull moduli. SIGNIFICANCE: With glazed groups showing height losses closer to the CG, glazing should be preferred to polishing when approximating the wear behavior of a natural dentition. Finishing of monolithic zirconia by glazing with a lithium silicate-based spray is recommended to preserve the antagonists. All examined zirconia crowns presented sufficient mechanical properties to withstand masticatory forces, even after prolonged aging.

A study on the discoloration of different dental porcelain systems.

Purpose: This study aimed to investigate the discoloration of four types of dental porcelain systems (feldspathic, monolithic zirconia, lithium disilicate, and leucite glassceramic) with various surface treatments (glazed and mechanically polished) after undergoing chewing simulation against a natural tooth antagonist. Materials and methods: Disc-shaped porcelain groups (9x3mm) were produced for the following categories: feldspathic glazed (FG), feldspathic mechanically polished (FM), zirconia glazed (ZG), zirconia mechanically polished (ZM), lithium disilicate glazed (ExG), lithium disilicate mechanically polished (ExM), leucite glass-ceramic glazed (EG), and leucite glass-ceramic (EM). In vitro chewing simulation was conducted on all porcelain groups, and a spectrophotometer was used to compare the color changes between their initial states. Results: The ΔE values (discoloration) of all porcelain samples were statistically different (p <0.05), and the ΔE values of the glazed samples were higher than those of the mechanically polished samples. Conclusion: All the glazed samples are more likely to show more color change than the mechanically polished sample groups.

Origin and Evolution of Cracks in the Glaze Surface of a Ceramic during the Cooling Process.

Because of the significant difference between the thermal expansion coefficients of ceramic blank and glaze, the glaze typically undergoes more pronounced shrinkage than the blank during ceramic cooling, which results in high stress concentrations and cracking. In this study, the mechanical mechanism of glaze cracking is studied, based on the statistical strength theory, damage mechanics, and continuum mechanics. Furthermore, the influence of the glaze layer thickness, heat transfer coefficient, expansion coefficient, and temperature difference on the creation and propagation of inner microcracks is systematically investigated, and the final discrete fracture network of ceramics is discussed at the specific crack saturation state. The results show that (1) a higher heat transfer coefficient will lead to a more uniform distribution of the surface temperature and a faster cooling process of the ceramics, reducing the number of microcracks when the ambient temperature is reached; (2) the thinner glaze layer is less prone to cracking when its thickness is smaller than that of the blank. However, when the thickness of the glaze layer is similar to that of the blank, the increased thickness of the glaze layer will increase the number of cracks on its surface; and (3) when the expansion coefficient of the glaze layer is smaller than that of the blank, cracks will not occur inside the glaze layer. However, as the coefficient of the thermal expansion of the glaze layer continuously rises, the number of cracks on its surface will first increase and then decrease.

Finishing and Polishing Procedures and Glaze Application on Physical Properties of a Fine-Structure Feldspathic Ceramic.

The aim of this study was to verify the effect of finishing and polishing procedures and glaze application on biaxial strength and surface properties of milled feldspathic ceramic blocks. Forty disc-shaped samples (14 mm diameter, 1.2 mm thickness) were divided in four groups (n = 10): C (control): no finishing and polishing; FP: finishing and polishing; G: glaze; and GFP: finishing and polishing + glaze. The specimens were subject to surface gloss (glossmeter) and roughness (profilometer) tests followed by biaxial flexural strength (universal testing machine) and Vickers hardness (microhardness tester) tests. The surface morphological analysis was performed by scanning electron microscopy (n = 3). Data were submitted to normality tests with Shapiro-Wilk, and one-way ANOVA followed by Tukey's post hoc test (α = 0.05). Group C showed the lowest gloss. For the hardness test, groups C, FP, and GFP obtained the highest values without significant differences between them. Regarding the biaxial strength test, group C showed the lowest mean value. Both finishing and polishing methods (FP and GFP) showed surface properties similar or better than the control, and with higher biaxial strength.

Morphological and structural analysis of iron-rich porcelains excavated from the Jian kiln site of Song dynasty.

Iron-rich porcelains generally embrace relatively high iron concentration in the glaze and body, which have an important position in the history of ancient Chinese high-temperature ceramics. The colour and lustre of glaze patterns are closely related to the orientation and order of crystallisation. In this work, three representative types of iron-rich porcelains (persimmon red-glazed sample, oil spot-glazed sample and mirror black-glazed sample) were analysed by portable energy-dispersive X-ray fluorescence (PXRF), optical coherence tomography (OCT), optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and laser Raman spectroscopy (RS) to determine the morphology, chemical composition and microstructure. Results showed that layered structure was observed in both persimmon red and oil spot glazes, however with respective thickness. Besides, iron-enriched crystals mostly precipitated on glaze surface. For the persimmon red sample, multilayer microstructure consisting of three sublayers beneath glaze surface was identified. Crystals and dark red substrates were all made of ε-Fe2 O3 , implying that it was fired at a strong reducing atmosphere. But for the oil spot sample, large-scale leaf-shaped crystals were well characteristic of ε-Fe2 O3 , while small snowflake-shaped crystals were assigned to α-Fe2 O3 , indicating that the firing environment was partially reduced. In addition, there was no crystalline layer existing on surface of mirror black-glazed porcelain, and plain black glaze layer was featured by a glassy matrix. The Jian kiln is a famous ancient folk kiln in the southern China that is currently located in Jianyang county of Fujian province. Its production of black-glazed porcelain began in the Tang dynasty (618-907 AD), became prosperous in the Southern Song dynasty (1127-1279 AD), and declined and ended in the Yuan dynasty (1271-1368 AD). Black-glazed Jian tea bowls were perfect for highlighting the rich white tea decoction. The thick and lustrous black glaze of Jian bowls sometimes were featured by streaked or mottled patterns, usually recognised by 'hare's fur (HF)', 'oil spot (OS)', 'partridge spot (PS)' and so on, which were the crystalline markings of iron oxide precipitated during firing in the dragon kiln. Iron oxide acted as a colorant for black-glazed porcelain and, thus, was called as iron-rich porcelain. The unique patterns originated from local iron-enrichment raw materials and firing process, and the locally iron-enriched areas generated due to the supersaturated crystallisation of different iron oxide in the cooling period. It was generally believed that research studies on the crystallographic nature and growth mechanism of surface crystals would provide help for the manufacturing of ancient Chinese glazes. With this aim, three types of iron-rich porcelain excavated from the Jian kiln were selected to further study the forming cause and growth process of glaze patterns using a series of characterisation methods, like portable energy-dispersive X-ray fluorescence (PXRF), optical coherence tomography (OCT), optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and laser Raman spectroscopy (RS).

Strength of a Zirconia- Reinforced Glass-Ceramic After Diamond Bur Adjustment.

INTRODUCTION: Adjustments with diamond burs on the ceramic surface can affect its roughness and decrease flexural strength. This study evaluated the effect of polishing or glazing on the surface roughness and biaxial flexural strength of a zirconia-reinforced lithium silicate glass-ceramic upon adjustment with diamond burs. METHODS: Seventy disks were prepared according to ISO 6872 and divided into seven groups (n = 10) according to different adjustments and finishing processes. Surface roughness was measured prior to biaxial flexural strength testing. The topography was analyzed using an atomic force microscope , fracture markings were identified using a stereomicroscope and representative specimens were analyzed using scanning electron microscopy. RESULTS: The use of diamond burs significantly increased the surface roughness and decreased the strength of the evaluated ceramic (p⟨0.05). Polishing reduced the ceramic's roughness but resulted in flexural strength similar to that of the groups with wear (p⟩0.05). The glaze-treated specimens showed flexural strength statistically similar to the control group (p>0.05) but higher roughness, similar to those with wear. CONCLUSIONS: Polishing reduced the surface roughness but did not affect the biaxial flexural strength of the ZLS ceramic. At the same time, the application of glaze after wear increased the strength.

Influence of Different Finishing-Polishing Procedures and Thermocycle Aging on the Surface Roughness of Nano-Ceramic Hybrid CAD/CAM Material.

Aim: The aim of this study was to evaluate the effectiveness of different finishing-polishing (FP) procedures on reducing surface roughness of nanoceramic hybrid CAD/CAM material before and after thermocycle (TMC) aging. Materials and Methods: Nano-ceramic hybrid CAD/CAM specimens were subjected to 8 different (2-glaze and 6-mechanical) FP procedures as follows (n=20): 1. Optiglaze (OG) 2. Diamond glaze (DG), 3. Vita Enamic Polishing Set (VE), 4. VE+Gradia Diapolisher paste (VE-G) 5. VE+Super-Snap SuperBuff (VE-S) 6. Sof-Lex Disc kit (SL) 7. SL+Gradia Diapolisher paste (SLG) 8. SL+Super-Snap SuperBuff (SL-S). Surface roughness of each specimen was measured by using a contact profilometer. All specimens were artificially aged with TMC (5000 cycles, 5°C/55°C) and surface roughness measurements were repeated. One extra specimen from each group before and after TMC was examined with SEM. Surface roughness data were analyzed by repeated measures ANOVA, dependent t-test and Tukey test. Results: Significantly higher mean Ra values were found for groups OG and DG compared to other groups (P<0.05). Differences between glaze groups and differences between mechanical FP groups were not significant (P>0.05). Groups SL-S and DG demonstrated comparable results before and after TMC (P>0.05). SEM analysis revealed that surfaces of VE-S and SL-S groups were smooth and free of scratches. Conclusions: Mechanical FP procedures were more effective in reducing surface roughness of nanoceramic hybrid CAD/CAM material than glaze applications. Sof-Lex kit followed by Super-Snap SuperBuff disc application can be recommended as the mechanical FP procedure of choice considering that this method provided smooth surfaces that were maintained after TMC.

The use of boron based materials on efficiency of environmentally friendly porous ceramics.

In this study, the use of boron-based materials on efficiency of environmentally friendly porous ceramics was investigated. In this context, a glaze formulation was created that uses high amounts of frit and sintered at low temperatures. Boric acid and colemanite were added to glaze formulations and different alternative formulations were created by reducing the frit percentage. These materials were added to these glaze formulations in two different ways, calcined and raw. The glaze mixtures obtained from the formulations were applied on the ceramic body and fired at 950-1000-1020-1100-1200 °C in the laboratory oven. Crystal phase structures of glaze samples containing boric acid and colemanite were analyzed by X-Ray Crystallography (XRD) method. The surface properties and characterizations of the obtained samples were examined by scanning electron microscopy (SEM). Differential Thermal Analysis and Thermogravimetric analysis (DTA/TG) were performed to determine their thermal behavior and mass loss. As a result of the analysis, it was observed that boron derivatives are a good flux agent and do not have a negative effect on the surface and other technical properties of the glaze. In the formulations of glazes with high frit content and processed at low temperatures, the percentage of frit has been reduced and costs have been improved. Also, energy costs were improved with the reduction in firing temperatures. Considering the energy and raw material costs of this study, it is predicted that high efficiency will be achieved in the process.

Correlating the physico-chemical properties of two conventional glazed porcelain stoneware tiles in relation to cleanability and sanitization.

Keeping surfaces clean can reduce the spread of infections. In particular, to decrease the potential for SARS CoV-2 contamination, performing disinfection of high-touching surfaces. Several ceramic tiles and porcelain stoneware tiles with antimicrobial properties are already available on the market. However, the widespread use of antimicrobial glazed stoneware tiles may require to replace the ceramic surfaces already present in many buildings. The unfeasibility of such replacement can be due to both product durability (lifetime of a tile is usually long) and/or monetary restrictions. Furthermore, as porcelain stoneware per se does not have antimicrobial activity, these materials are fabricated by adding chemical agents able to provide antimicrobial properties. This approach requires a compatibility between the antimicrobial agents and the glaze formulation, as well as a careful control of the firing cycle and the final properties of the ceramic products. It follows that the final cost of antimicrobial tiles is not competitive with that of conventional tiles. In the latter, the persistence of potential pathogens on the surfaces is a crucial problem to face: the longer a pathogen survives on a surface, the longer it may be a source of transmission and thus endanger susceptible subjects. In this work, bacteria's capacity to adhere and to be effectively removed from two conventional glazed porcelain stoneware tiles (under dirty and clean conditions) was investigated. Two different glazes were tested, one mainly glassy (glossy) and the other mainly crystalline (matt). The sanitization procedures were carried out by chemical and chemo-mechanical procedures. The results showed that chemo-mechanical sanitization was the most effective, and the best results could be obtained on the stoneware tiles coated with the mainly glassy glaze, with the lowest porosity and the lower roughness values and water contact angles, especially under clean conditions.

Glazing as a bonding system for zirconia dental ceramics.

Studies have reported challenges of debonding of dental zirconia crowns to from luting cement and prepared teeth. The aim of the study was to explore the application of dental glazing systems for enhancing the bonding of zirconia dental ceramics to luting resin cement. Commercial glaze powder and liquid (Vita Akzent) and experimental mica-based glaze powders were used for the study. X-ray diffraction analysis of the glaze powders (XRD) and Fourier Transform InfraRed Spectroscopy (FTIR) was done on the glaze liquid. Sandblasted sintered dental zirconia (Katana, Noritake) were the control samples. Glazed zirconia samples were coated with commercial glaze and experimental glaze powders which were further etched with 5% hydrofluoric acid. Shear bond strengths of sandblasted and glazed zirconia samples to resin composites were evaluated. XRD of commercial and experimental glaze powders revealed a broad peak confirming the amorphous nature of glass and FTIR analysis of the glaze liquid revealed symmetrical stretching (CH2-CH3) of the alcohol group indicating a mixture of iso-butane and ethanol. Glazed and etched zirconia showed significantly higher shear bond strength to resin cement compared to sand-blasted zirconia. The study confirms the glassy nature of dental glaze powders and the presence of ethanol-based mixtures in the commercial glaze liquid. Glazing systems have the potential to be explored for enhancing the bonding of non-etchable zirconia ceramics to resin cement and tooth substrates.

Insights into the Residue Trapped in Glaze Cracks of Archaeological Ceramics Using Microchemical Analysis.

Searching for residue in the glaze of porcelain or stoneware is a difficult task because these glazes are high-fired, well vitrified, and nonporous. This paper analyzes the chemical composition of residue observed in glaze cracks of porcelain via SEM-EDS to determine how the crackle effect was produced, in particular, if it was intentionally created during production or the result of post-depositional processes. This study offers insights to a specific type of ancient Chinese porcelain called "Ge-type ware", which has two different types of cracks, and whose origin has been debated for nearly 60 years because it has never been found at any kiln site. This paper analyzes the chemical composition of the two crack types, first using elemental mapping to ascertain the different mechanisms that produced these two crack types of the Heirloom Ge ware, and second using residue analysis and chemical fingerprinting to determine the provenance of this puzzling type of porcelain. In doing so, this paper demonstrates how the residue in the glaze of porcelain can be observed and analyzed via microchemical approaches and hopes to inspire more research using this technique in future.

Source of Raw Materials and Its Processing for the Manufacturing of Ptolemaic Faience Bowls from Tell Atrib (Nile Delta, Egypt).

The provenance of siliceous grain material, the basic source of manufacturing faience items, is still a matter of discussion. The study methods applied so far have not brought satisfactory outcomes, and the results are ambiguous and problematic. Archaeological evidence has also not supplied adequate proof for establishing the sites where the source material was obtained and the methods of its preparation. Therefore, we propose an interdisciplinary approach to solve these research problems. We explore selected material of 7 faience bowls precisely dated on the c. 100 years of the Ptolemaic Period in Egypt. The body and glaze of the faience bowls was qualitatively and quantitatively tested with regard to chemical and mineral composition, and selected material parameters. Based on structural-textural analysis, as well as chemical and mineral composition, the source area of the studied raw material and its potential excavation site was determined in the Eastern Desert. The obtained results were compared with locations of mines exploiting gold-bearing quartz veins, functioning in the Ptolemaic Period. Material parameters obtained from image analysis have been applied to reconstruct the processes of crushing and grinding of the quartz material and its further treatment for faience manufacturing. Quartz treatment was analysed with regard to tools and handling processes applied in Ptolemaic mines. We assume that such an approach has given accurate results in determining the provenance of siliceous material used in the Ptolemaic workshops of Athribis. Therefore, in material studies of artefacts produced in the antiquity, it is indispensable to use an interdisciplinary and complex approach, beginning from field studies and ending with detailed laboratory analyses.

Study on freezing characteristics of the surface water film over glaze ice by using an ultrasonic pulse-echo technique.

This study proposes an ultrasonic pulse-echo technique to examine the freezing characteristics of a thin film of water over ice, and uses it to develop a method to measure the thickness of glaze ice. A multilayer model is first introduced to simulate ultrasonic transmission through multiple media. A transition layer is then inserted between the layers of ice and water, and its properties were in gradient form along the direction of thickness. Following this, a high-frequency ultrasonic experimental device is developed to dynamically measure variations in the thickness of the layers of ice and water. The accuracy of the proposed model of the transition layer was validated by showing that its numerical results agreed well with those of experiments. The results show that the amplitude of echo from the top of the ice layer was at its minimum when the thickness of the film of water was in the range of [40, 45] µm, and increased when the film of water was thinner than 40 µm. A delay in echo from the top of the layer of ice was observed when measuring its thickness because the film of water froze, which yielded a relative error of 3.34%. The proposed numerical model can thus efficiently measure the thickness of glaze ice.

English delftware (c. 1770) from Bristol, Lancaster and Liverpool: A composition study using Raman spectroscopy and electron microscopy.

Nine decorated lead-tin glazed earthenwares, colloquially termed 'delftware', produced in c. 1770 in Bristol, Lancaster and Liverpool, England, have been analysed non-invasively by Raman spectroscopy and electron microscopy. The body paste used to manufacture these west coast wares was attained by the blending of highly dolomitic [CaMg(CO3)2] "blue" clay sourced from Carrickfergus, County Antrim, Ireland, with locally sourced clays. Thus, the resulting body fabric of these wares contains significant MgO enabling them to be differentiated from MgO-free London manufactured delftware. The glazes employed all contain arsenic, obtained as a cobalt impurity or by deliberate addition. The presence of this unvolatilised arsenic in the glaze has then reacted with the lead during firing at temperatures approaching 1000 °C and then further reacted with calcium and magnesium to form needle-like crystals of lead arsenates in the form of mimetite [Pb5(AsO4)(Cl,OH)], schulténite [Pb(AsO3OH)], ß-roselite [Ca2Co(AsO4)2·2H2O], hedyphane [Ca2Pb3(AsO4)3Cl], wendwilsonite [Ca2Mg(AsO4)2·2H2O] and/or adelite [CaMgAsO4(OH)] during high temperature firing.

Full Spectral Range Raman Signatures Related to Changes in Enameling Technologies from the 18th to the 20th Century: Guidelines, Effectiveness and Limitations of the Raman Analysis.

This study investigates the comparison of the Raman signatures of different phases used in underglaze, inglaze and overglaze decors of selected European, Chinese and Japanese porcelains and enameled metalworks, which are particularly representative of technological developments in enameling. Specifically, the article deals with the main structural types or host networks (corundum/hematite, spinels, zircon, cassiterite, pyrochlore, apatite, sphene, etc.) used for colored enamels on porcelain, earthenware or metal rather than considering all types of pigments and opacifiers. According to the results, Raman microspectroscopy allows identifying of the fingerprint spectra of milestone technologies and represents a simple and rapid tool for detecting copies. Particular attention is paid to the information deduced from the examination of the associated 'background' and signatures from electronic transitions induced by uncontrolled traces or voluntary addition of rare earths (luminescence). The relationship between the grinding procedure and Raman signature is also discussed.

Advances in Nanoarchitectonics of Antimicrobial Tiles and a Quest for Anti-SARS-CoV-2 Tiles.

Design of antimicrobial tiles seems necessary to combat against contagious diseases, especially COVID-19. In addition to personal hygiene, this technology facilitates public hygiene as antimicrobial tiles can be installed at hospitals, schools, banks, offices, lobbies, railway stations, etc. This review is primarily focused on preparing antimicrobial tiles using an antimicrobial layer or coatings that fight against germs. The salient features and working mechanisms of antimicrobial tiles are highlighted. This challenge is a component of the exploratory nature of nanoarchitectonics, that also extends farther than the realm of nanotechnology. This nanoarchitectonics has been successful at the laboratory scale as antimicrobial metal nanoparticles are mainly used as additives in preparing tiles. A detailed description of various materials for developing unique antimicrobial tiles is reported here. Pure metal (Ag, Zn) nanoparticles and a mixture of nanoparticles with other inorganic materials (SiO2,, TiO2, anatase, nepheline) have been predominantly used to combat microbes. The developed antimicrobial tiles have shown excellent activity against a wide range of Gram-positive and Gram-negative bacteria. The last section discussed a hypothetical overview of utilizing the antimicrobial tiles against SARS-CoV-2. Overall, this review gives descriptive knowledge about the importance of antimicrobial tiles to create a clean and sustainable environment.