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A series of 22 figured Phoeno-Punic and Roman terra-cottas, of high relevant archaeological and patrimonial values, have been studied. The samples were recovered in the Roman Theatre of Malaga (Spain). A thorough analysis including stereomicroscopy, elemental analysis by WDXRF, mineralogical analysis by XRPD coupled with the Rietveld method, and SEM, has been carried out. Highly diluted fused glass beads probed to be enough for the X-ray fluorescence analyses, minimizing the damage to the samples. For selected samples, in addition to the classical use of the Rietveld method, the G-factor external-standard approach has been employed to get full quantitative crystalline and amorphous phase analysis. The analytical results allow proposing a local regional provenance for the main part of the samples, being a relevant data for several artifacts, not contextualized due to stratigraphic alterations in the site. In addition, some relevant samples, for instance a theatrical mask fragment (TRC005), are likely foreign. The overall amorphous is not negligible in phase quantification, accounting for up to 50 wt %. Technologically, all terra-cotta samples are similar, made of calcareous clays, fired at ~700-950 ºC.Se han estudiado 22 terracotas figuradas feno-púnicas y romanas, de alto valor arqueológico y patrimonial. Las muestras proceden de las excavaciones del Teatro romano de Málaga (España). El análisis realizado incluye estereomicroscopía, análisis elemental mediante WDXRF, análisis mineralógico cuantitativo mediante el método de Rietveld de los datos de XRPD y SEM. Para minimizar el daño realizado a las muestras, se prepararon perlas muy diluidas, que han demostrado ser suficientes para los análisis de fluorescencia de rayos-X. Para muestras selectas, además del análisis usual mediante el método de Rietveld, se ha utilizado el método del estándar externo mediante el factor-G para obtener análisis cuantitativos de fases cristalinas y amorfas. Los resultados analíticos permiten proponer una procedencia local/regional para la mayor parte de las muestras, siendo esta información de gran interés para algunas piezas descontextualizadas debido a alteraciones estratigráficas en el yacimiento. Adicionalmente, algunas piezas relevantes, como un fragmento de máscara teatral (TRC005) son posiblemente piezas de importación. La cuantificación de la fracción amorfa indica que la magnitud de ésta no puede ser despreciada en las cuantificaciones, llegando a ser cercana al 50 wt %. Tecnológicamente, todas las terracotas son muy similares, fabricándose en arcillas calcáreas cocidas entre unos 700 y 950 ºC.

Terra Sigillata was a Roman pottery, which was also produced in several workshops in Hispania. Two known workshops at Granada (Cartuja and Carmen de la Muralla, or Albayzin) are known to have produced both typical Terra Sigillata and low-gloss coating related pottery. Potsherds from these workshops have been thoroughly studied from an archaeological approach, but not by analytical chemistry techniques. Here, we report a full characterization of nine selected samples from these workshops and also a tenth sample, Terra Sigillata made in the Gaul, for comparison. The pastes characterization includes elemental analysis from XRF and quantitative mineralogical analysis by Rietveld analysis of XRPD data. Cluster analysis to both types of data has been carried out. SEM-EDX and GI-XRPD have been used to characterize the slips of the pottery. The elemental analysis results for the pastes suggest that terra sigillata potsherds from both workshops were likely made from the same clay, different to that used to make the low-gloss coating pottery. The firing temperatures have been estimated from the phase assemblages being about 900-950ºC for the Granada sigillata.La Terra Sigillata fue una cerámica romana, que se produjo también en varios talleres en Hispania. Los talleres ubicados en Granada (Cartuja y Carmen de la Muralla, o Albayzín) produjeron Terra Sigillata y cerámicas de barniz mate. Ambos talleres han sido ampliamente estudiados desde un punto de vista arqueológico, pero no mediante técnicas analíticas. En este trabajo, se estudian nueve muestras de estas producciones, y una décima de Terra Sigillata producida en la Galia, para su comparación. La caracterización de las pastas incluye análisis elemental por XRF, y análisis mineralógico cuantitativo mediante análisis de Rietveld de los datos de XRPD. Estos dos conjuntos de datos también se han evaluados mediante análisis de cluster. Los recubrimientos superficiales se han caracterizado mediante SEM-EDX y GI-XRPD. Los análisis sugieren que ambos talleres utilizaron probablemente la misma materia prima para la Terra Sigillata, y otra diferente en las cerámicas de barniz mate. Se ha estimado una temperatura de cocción para la Sigillata en el intervalo 900-950ºC.

Abstract: This work evaluates the potential of zirconium titanate–zirconia composites for thermal shock. Materials with Zr0.97Y0.03O1.985:TiO2 molar ratios 50:50 (Z(Y)T50) and 70:30 (Z(Y)T70) were obtained from Y2O3 (3mol%)-stabilized ZrO2 and TiO2 mixtures colloidal processed and reaction sintered at 1773K with low cooling rate (2–5K/min). The crystalline phases and their unit cell parameters were determined by Rietveld analysis of high resolution X-ray diffraction patterns. The zirconium titanate phase in these materials is o-TiZrO4, being the major phase in Z(Y)T50 in which c-ZrO2 is secondary phase. Z(Y)T70 has t-ZrO2 as main phase, o-TiZrO4 as secondary phase and c-ZrO2 and m-ZrO2 as minor phases. The Hasselman thermal shock resistance factors, calculated using the experimental values of the involved properties, Young''s modulus, thermal expansion coefficient, and fracture strength, have demonstrated the high potential of zirconia–zirconium titanate composites for thermal shock applications in oxidizing atmospheres. [Copyright &y& Elsevier]

Abstract: Zirconium titanate, ZrTiO4, is a well known compound in the field of electroceramics. Furthermore, it shows a large potential as structural material for thermal shock resistance applications, since it presents crystallographic anisotropy in thermal expansion. However, there is no information in the current literature about its thermomechanical behaviour. In this work, single phase zirconium titanate bulk materials have been prepared from well dispersed ZrO2 and TiO2 mixed suspensions, combining reaction and conventional sintering processes. The crystal structures of ZrTiO4 have been studied by the Rietveld method for bulk samples. The structural evolution upon the cooling rate has been unravel, as the b-axis strongly decreases for slow cooled samples when compared to quenched materials. For the first time apparent Young''s modulus (≈130GPa) and Vickers hardness (≈8GPa) values of a fully dense single phase zirconium titanate material have been evaluated and its potential for thermal shock applications has been analysed in comparison with other thermal shock resistant materials. [Copyright &y& Elsevier]

Portland cements (PCs) and cement blends are multiphase materials of different fineness, and quantitatively analysing their hydration pathways is very challenging. The dissolution (hydration) of the initial crystalline and amorphous phases must be determined, as well as the formation of labile (such as ettringite), reactive (such as portlandite) and amorphous (such as calcium silicate hydrate gel) components. The microstructural changes with hydration time must also be mapped out. To address this robustly and accurately, an innovative approach is being developed based on in situ measurements of pastes without any sample conditioning. Data are sequentially acquired by Mo K α 1 laboratory X-ray powder diffraction (LXRPD) and microtomography (µCT), where the same volume is scanned with time to reduce variability. Wide capillaries (2 mm in diameter) are key to avoid artefacts, e.g. self-desiccation, and to have excellent particle averaging. This methodology is tested in three cement paste samples: (i) a commercial PC 52.5 R, (ii) a blend of 80 wt% of this PC and 20 wt% quartz, to simulate an addition of supplementary cementitious materials, and (iii) a blend of 80 wt% PC and 20 wt% limestone, to simulate a limestone Portland cement. LXRPD data are acquired at 3 h and 1, 3, 7 and 28 days, and µCT data are collected at 12 h and 1, 3, 7 and 28 days. Later age data can also be easily acquired. In this methodology, the amounts of the crystalline phases are directly obtained from Rietveld analysis and the amorphous phase contents are obtained from mass-balance calculations. From the µCT study, and within the attained spatial resolution, three components (porosity, hydrated products and unhydrated cement particles) are determined. The analyses quantitatively demonstrate the filler effect of quartz and limestone in the hydration of alite and the calcium aluminate phases. Further hydration details are discussed., Competing Interests: The authors declare no conflict of interest., (© Jaime Fernandez-Sanchez et al. 2024.)

The fabrication of pectin-cellulose nanocrystal (CNC) biocomposites has been systematically investigated by blending both polysaccharides at different relative concentrations. Circular free-standing films with a diameter of 9 cm were prepared by simple solution of these carbohydrates in water followed by drop-casting and solvent evaporation. The addition of pectin allows to finely tune the properties of the biocomposites. Textural characterization by AFM showed fibrous morphology and an increase in fiber diameter with pectin content. XRD analysis demonstrated that pectin incorporation also reduced the degree of crystallinity though no specific interaction between both polysaccharides was detected, by ATR-FTIR spectroscopy. The optical properties of these biocomposites were characterized for the first time and it was found that pectin in the blend reduced the reflectance of visible light and increased UV absorbance. Thermal stability, analyzed by TGA, was improved with the incorporation of pectin. Finally, pectin-cellulose nanocrystal biocomposites showed a good biodegradability in seawater, comparable to other common bioplastics such as cellulose and low-molecular weight polylactide, among others., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Multifunctional materials, especially those combining two or more properties of interest, are attracting immense attention due to their potential applications. MOFs, metal organic frameworks, can be regarded as multifunctional materials if they show another useful property in addition to the adsorption behavior. Here, we report a new multifunctional light hybrid, MgH(6)ODTMP·2H(2)O(DMF)(0.5) (1), which has been synthesized using the tetraphosphonic acid H(8)ODTMP, octamethylenediamine-N,N,N',N'-tetrakis(methylenephosphonic acid), by high-throughput methodology. Its crystal structure, solved by Patterson-function direct methods from synchrotron powder X-ray diffraction, was characterized by a 3D pillared open framework containing cross-linked 1D channels filled with water and DMF. Upon H(2)O and DMF removal and subsequent rehydration, MgH(6)ODTMP·2H(2)O (2) and MgH(6)ODTMP·6H(2)O (3) can be formed. These processes take place through crystalline-quasi-amorphous-crystalline transformations, during which the integrity of the framework is maintained. A water adsorption study, at constant temperature, showed that this magnesium tetraphosphonate hybrid reversibly equilibrates its lattice water content as a function of the water partial pressure. Combination of the structural study and gas adsorption characterization (N(2), CO(2), and CH(4)) indicates an ultramicroporous framework. High-pressure CO(2) adsorption data are also reported. Finally, impedance data indicates that 3 has high proton conductivity σ = 1.6 × 10(-3) S cm(-1) at T = 292 K at ~100% relative humidity with an activation energy of 0.31 eV.

A new flexible ultramicroporous solid, La(H(5)DTMP)·7H(2)O (1), has been crystallized at room temperature using the tetraphosphonic acid H(8)DTMP, hexamethylenediamine-N,N,N',N'-tetrakis(methylenephosphonic acid). Its crystal structure, solved by synchrotron powder X-ray diffraction, is characterised by a 3D pillared open-framework containing 1D channels filled with water. Upon dehydration, a new related crystalline phase, La(H(5)DTMP) (2) is formed. Partial rehydration of 2 led to La(H(5)DTMP)·2H(2)O (3). These new phases contain highly corrugated layers showing different degrees of conformational flexibility of the long organic chain. The combination of the structural study and the gas adsorption characterization (N(2) and CO(2)) suggests an ultramicroporous flexible framework. NO isotherms are indicative of a strong irreversible adsorption of NO within the pores. Impedance data indicates that 1 is a proton-conductor with a conductivity of 8 × 10(-3) S cm(-1) at 297 K and 98% of relative humidity, and an activation energy of 0.25 eV.