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The influence of barium oxide on glazes in the SiO 2 -Al 2 O 3 -CaO-MgO-K 2 O system was investigated. Samples were prepared with 0, 2.5, 5 and 7.5 wt% of barium oxide added to this system. The glazes were fired at 1240 °C and the structure and surface properties were determined. Qualitative and quantitative analyses of phase composition, surface properties, structural mid-infrared analysis, and microstructure were performed. Diopside was detected in all glazes as the MgO content was higher than 2.5 wt%. Hyalophane crystals were observed when the BaO content increased to 5 wt%. Mid-infrared studies showed that the appearance of crystalline phases ordered the structure of the glazes; on the other hand, the amorphous phase increased its disorder related to the higher amount of modifying barium cations. The addition of barium oxide did not significantly affect the color of the surface but caused an increase in roughness due to surface crystallization. The microhardness increased with an increased amount of barium in the amorphous phase. [ABSTRACT FROM AUTHOR]

Bioceramics composed of calcium and magnesium silicates have garnered increasing attention for the development of porous scaffolds in bone tissue engineering (BTE). This heightened interest is primarily attributed to their remarkable bioactivity and their capacity to form strong bonds with hard tissue. Fabricating nanocomposite scaffolds is a recognized approach for improving the characteristics of scaffolds used in BTE. This research investigates the mechanical and biological properties, antibacterial activity, and drug-release characteristics of scaffolds composed of akermanite (AKT), monticellite (MON), and monticellite-akermanite (MON-AKT). These scaffolds were fabricated utilizing the space holder process. Additionally, the in vitro drug release profile and antimicrobial activity of Azithromycin (AZT)-loaded MON-AKT composite scaffolds were investigated. The findings showed that the Mon-15 wt% AKT nanocomposite scaffold had the highest density, the smallest grain and micropore sizes, and the lowest porosity. In contrast, integrating AKT into MON-based composite scaffolds resulted in materials characterized by high mechanical strength and stability within physiological environments. The MON-AKT nanocomposite scaffolds exhibited cytocompatibility and demonstrated a high level of alkaline phosphatase (ALP) activity in osteogenic studies. Furthermore, antimicrobial activity assessments revealed that the AZT-encapsulated MON-AKT composite scaffolds effectively inhibited the growth of both S. aureus and E. coli bacteria. The outcomes showed that the antibacterial efficacy of the scaffold depends on both the amount of AZT and the type of bacteria. Overall, MON-AKT/3AZT scaffolds exhibited significantly superior bacterial inhibition compared to other scaffolds, making it a promising option for treating bone tissue defects. [ABSTRACT FROM AUTHOR]

Magnesium slag (MS) and fly ash (FA) are industrial wastes that must be utilized in a clean, effective, and massive method to avoid environmental pollution. In this study, the preparation of diopside-augite-based glass-ceramics was theoretically analyzed and experimentally conducted by disposal of MS and FA with chromium oxide (Cr 2 O 3) as a nucleating agent. The thermodynamics analysis first indicated that pyroxene could be the main crystal phase of the target glass-ceramics for the co-utilization of both wastes. The experimental results indicated that the main phase in prepared glass-ceramics samples was diopside ([Ca(Mg, Fe, Al)(Si, Al) 2 O 6 ], and the degree of glass network polymerization was enhanced with the FA in raw material increasing from 50 wt% to 65 wt%. Plus, the crystal size of the prepared glass-ceramics was gradually refined by increasing the FA. The optimized conditions were given as controlling nucleation at 790 °C for 2 h and crystallization at 929 °C for 2 h of the parent glass that derived from 40 wt% MS and 60 wt% FA as raw materials, 1 wt% Cr 2 O 3 as nucleating agent. The resulting glass-ceramics had excellent properties and chemical stability, such as a density of 3.11 g cm−3, bending strength of 101.98 MPa, acid resistance of 98.34 %, and alkali resistance of 99.53 %. This study provided a route to produce eco-friendly glass-ceramics material for architectural decoration by high-efficiency utilization of MS and FA. [ABSTRACT FROM AUTHOR]

The present work studies the rodingite that is recorded for the first time as being associated to Al-Barramiya Neoproterozoic ophiolite at Eastern Desert of Egypt, Arabian-Nubian Shield (ANS). Al-Barramiya ophiolite is one of the most important ophiolitic sequences exposed in the ANS. It is affected by different styles of alterations included carbonatization, listvenitization, chloritization and rodingitization. The Neoproterozoic ophiolitic rocks of Al-Barramiya district consists of serpentinized peridotite and metagabbros. Serpentinized peridotites are highly altered to assemblages of talc-carbonate rocks, listvenite and magnesite, while metagabbro is partly converted into rodingite. The field studies indicate that serpentinite and rodingite in Al-Barramiya area display high-strain cataclastic deformation. Rodingite consists of garnet, diopside, vesuvianite and chlorite with minor epidote, prehnite, actinolite and opaque minerals. The garnets and vesuvianite are mostly concentrated near the peripheries of the studied rodingite masses, while clinopyroxene, chlorite, epidote and prehnite gradually increase inwards due to progressive decreasing water/rock ratio as fluids originally buffered by serpentinite move towards equilibrium with gabbroic bulk chemistry. Some rodingite samples preserve a few relics of igneous textures of ophiolitic metagabbros. Garnets are distinguished into andradite, hydroandradite and grossular. Pyroxene is represented mainly by secondary clinopyroxene beside primary fresh relics of diopside; the latter has high Mg# (0.92–0.97) similar to ophiolitic clinopyroxene in the ANS. Rodingite is enriched in CaO, Fe2O3 and MgO but depleted in SiO2, Al2O3 and Na2O compared to associated metagabbro. The association of rodingite with serpentinites and metagabbros suggests that Al-Barramiya rodingite is genetically related to serpentinization of ultramafic rocks. The rodingitization occurred during ocean floor alteration contemporaneous with the serpentinization process. The superposition of cataclastic deformation on the altered rocks indicates that alteration preceded obduction and occurred on the seafloor of the suprasubduction zone where Al-Barramiya ophiolite was originally emplaced. During serpentinization the olivine in the peridotite broke down and released Mg2+ in the metasomatic fluids and clinopyroxene broke down producing Ca-rich fluids. These fluids react with the mafic protoliths and enrich them in MgO and CaO. Also, serpentinization fluids react with the plagioclase of the metagabbro, releasing Ca from the mafic source and concentrated it in the rodingitized samples. The positive Eu anomalies beside high Sr contents of the rodingite can be inherited from a plagioclase-rich protolith such as ophiolitic metagabbro. The enrichment of rodingite in Th and U indicates two distinct solutions affected the gabbroic protolith because the alteration of depleted peridotite to serpentinite cannot be an efficient source to enrich these elements. The present study indicates that the rodingitization process underwent lower greenschist facies conditions associating metamorphism that caused serpentinization and released Ca-rich metasomatic fluids. [ABSTRACT FROM AUTHOR]

Since the introduction of 3D printing to biomedical fields, numerous advancements have been achieved in tissue engineering due to the advantages it offers. However, 3D-printed polymeric scaffolds may lack certain properties, impacting their functionality and success, such as bioactivity and cell affinity. In this study, the dip coating method was employed to enhance the biological and mechanical properties of 3D-printed polylactic acid (PLA) scaffolds using fused deposition modeling (FDM) technology. Specifically, the scaffolds were dip-coated with a polyvinyl alcohol (PVA)/nano-diopside solution. The thermal features of the 3D-printed scaffolds were analyzed using the differential scanning calorimetry method, revealing a calculated crystallinity of about 13%. To assess bioactivity, both coated and non-coated scaffolds were immersed in simulated body fluid (SBF) for 28 days, and their evaluation was conducted through scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDAX). At 40 °C, compared to the thermal conductivity of the nanofluid, the thermal conductivities of the non-coated 3D-printed sample and the coated 3D-printed sample were reduced by 9.91 and 22.52%, respectively. The results of this study guided the design and fabrication of improved tissue engineering scaffolds for bone regeneration applications. [ABSTRACT FROM AUTHOR]

Phosphorus is often present in meteorites as the mineral schreibersite, in which P is in a reduced oxidation state as a phosphide. Phosphides such as schreibersite have been proposed to be important to the development of life on the earth and may serve as indicators of metamorphic grade on meteorite parent bodies. Here we investigate how synthetic schreibersite (as the iron end-member, Fe 3 P) oxidizes into calcium phosphates through reaction with silicates under high temperature conditions, at specific oxygen fugacities, and in the absence of water. We find that schreibersite readily oxidizes to phosphates at temperatures of 750–850 °C over a few weeks depending on the oxygen fugacity of the environment. The rate of this process is best matched by diffusion-limited kinetics. Therefore, the metamorphic heating timescale required to equilibrate phosphorus in meteoritic samples with small schreibersite grains (∼1 μm), such as in the type 3 ordinary chondrites (3.0–3.3), was short (10–100 days). [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to the low-temperature synthesis of cobalt-containing diopside pigments based on granulated blast furnace slag and to study the characteristics of the mineral formation processes, changes in the structure and colour indices. Design/methodology/approach: Synthesis of cobalt-containing diopside pigments based was carried out by the directional formation of the mineralogical composition with the introduction of part of the components using granulated blast-furnace slag. Findings: It has been established that the formation of the diopside phase in pigments containing blast-furnace slag as the main component proceeds at low temperatures (1,100°C–1,150 °C). The colour of diopside pigments is formed because of the isomorphic substitution of Si4+ ions for Al3+ ions and Mg2+ ions for Co2+ ions. It is expedient to add CoO in an amount of 0.9 mol (18 Wt.%) into the composition of diopside pigments based on blast-furnace slag to obtain defect-free violet glazes. Practical implications: The developed diopside pigments enable obtaining of high-quality violet glazes for ceramics. The application of the obtained results can significantly reduce the consumption of traditional raw materials in the composition of silicate ceramic pigments, as well as reduce their firing temperature. Originality/value: Calcium, magnesium and silicon oxides are the main components of blast-furnace slag. In addition, granulated blast furnace slag is mainly represented by the glassy phase, which determines its high activity during the firing process. These factors are prerequisites for using the blast-furnace slag as a valuable substitute for chemically pure or natural raw materials in silicate pigments and reducing their firing temperature. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the authorship, provenance, and technology of the mudejar enamelled tiles from the Olite Castle (northern Spain, 14th century). According to previous knowledge, Olite's enamelled tiles had been manufactured in Manises (Valencia, Spain). The analysis of ceramic pastes revealed the existence of two different chemical compositions, suggesting the use of two different clay sources, probably one from the Tudela area, and another from the Tafalla–Olite area. Those probably made in the Tudela area stood out with a higher diopside (CaMgSi2O6) content. Those probably made in the Tafalla–Olite area stood out for their calcium-bearing minerals, such as calcite (CaCO3) or gehlenite (Ca2Al(AlSi)O7). On this basis, production in Manises has been ruled out. However, it is highly probable that the artisans of Manises would have led the production from Tudela. The study of the firing temperatures and composition of the enamels indicated that the production methods and materials used in Tafalla–Olite (800–850 °C) and Tudela (higher than 900 °C) were different, reflecting the influence of local and Manises artisans, respectively. In Olite tiles, enamel was applied following recipes from the 14th and 15th centuries. [ABSTRACT FROM AUTHOR]

Borosilicate glasses are the primary waste forms for the industrial immobilization of high‐level liquid waste. Yet, the compositional variation of waste glasses can form the diopside phase, which can be detrimental to the melting process and the properties of the final glass products. This study prepared simulated waste glasses with variable contents of alkaline earth metals, boron, transition metals, and rare earth metal oxide and subjected them to heat treatments. The effect of the compositional variation on the diopside crystallization behavior was explored using differential scanning calorimetry, X‐ray diffraction, optical microscopy, and scanning electron microscopy‐energy dispersive spectroscopy. The results revealed that the average size of diopside crystals was proportional to the square root of the heat treatment durations. Increased contents of alkaline earth and transition metal oxides could contribute to the growth of diopside crystals, while boron oxide tended to inhibit it. Finally, a prediction model correlating the average crystal size, compositional variation, and heat treatment durations was discussed. [ABSTRACT FROM AUTHOR]

Bioactive glasses in the CaO–MgO–Na2O–P2O5–SiO2–CaF2 system are highly promising materials for bone and dental restorative applications. Furthermore, if thermally treated, they can crystallize into diopside–fluorapatite–wollastonite glass-ceramics (GCs), which exhibit appealing properties in terms of mechanical behaviour and overall bone-regenerative potential. In this review, we describe and critically discuss the genesis, development, properties and applications of bioactive glass "1d" and its relevant GC derivative products, which can be considered a good example of success cases in this class of SiO2/CaO-based biocompatible materials. Bioactive glass 1d can be produced by melt-quenching in the form of powder or monolithic pieces, and was also used to prepare injectable pastes and three-dimensional porous scaffolds. Over the past 15 years, it was investigated by the authors of this article in a number of in vitro, in vivo (with animals) and clinical studies, proving to be a great option for hard tissue engineering applications. [ABSTRACT FROM AUTHOR]

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The rapid development of fifth/sixth-generation (5 G/6 G) telecommunication technologies has led to increased demands for silicate ceramic materials. In this work, Ge4+-substituted diopside, CaMg 0.9 Zn 0.1 Si 2- x Ge x O 6 (CMZSG, x = 0.0–2.0) ceramics were synthesized via the conventional solid-state method. All samples were sintered densely at 1200 ℃ for 4 h. CMZSG ceramics keep a single phase with C 2/ c and the lattice parameters vary smoothly with x. When 0.1 ≤ x ≤ 0.8, Ge4+ substitution prevents the abnormal grain growth. CMZSG ceramics have enhanced dielectric properties after substituting Ge4+, and the sample with x = 0.1 has the greatest dielectric properties with ε r = 7.78 and Q × f = 190,300 GHz. The dielectric properties in the microwave and terahertz bands are compared, and the larger ε r and Q × f values in the terahertz band are found due to the withdrawal of the partial polarization mechanism and different measurement methods. The relationship between lattice distortions and the dielectric properties is established. Both the local distortion in [Si/GeO 4 ] tetrahedra chain and the distortion within [Si/GeO 4 ] tetrahedron are found to contribute to the enhancement of Q × f values. Furthermore, the increased lattice expansion and the distortion within [Si/GeO 4 ] tetrahedron contribute to a larger negative τ f. These conclusions can guide us to design silicate ceramics with higher Q × f values and near-zero τ f for application. The CaMg 0.9 Zn 0.1 Si 1.9 Ge 0.1 O 6 ceramics exhibit excellent dielectric properties with ε r = 7.48 and Q × f = 303,400 GHz in the terahertz band, rendering it a promising dielectric material for future terahertz mobile communication systems. • The Q × f values in the microwave and terahertz bands vary in the same trend. • Bond strains are calculated from the distortion theorem of the bond-valence theory. • The Q × f values and τ f have strong correlation with lattice distortion. [ABSTRACT FROM AUTHOR]

Limestone is the most widely used agricultural input for soil acidity correction and calcium (Ca) and magnesium (Mg) fertilization. However, other materials have the potential to fulfill these purposes, such as steel slags, also known as silicates. Silicates have higher solubility than limestone, serving as agents for increase pH in no‐till, in addition to being a source of Ca, Mg, and silicon (Si). This study aimed to compare the effects of surface application of dolomitic lime and calcium magnesium silicate on soil chemical properties, soybean [Glycine max (L.) Merr.] nutritional status, and grain yield under no‐till. The experiment was installed in the northwest Paraná State, Brazil, on a Rhodic Eutrustox. Lime and silicate rates were applied by broadcasting before the sowing of soybean. Silicate treatment increases soil Ca2+, pH, and base saturation up to a depth of 0.10 m. By contrast, liming effects on soil chemistry were restricted to the 0.05 m top layer after 24 months of application. The acidity correction and Ca2+ supply to greater soil depths and the increased leaf Si as a beneficial element provided by silicate treatment contributed to increasing soybean yield in the 2018/2019 and 2019/2020 seasons. Lime application, regardless of the rate, did not improve soybean yield. Waste from the steel industry can be used as acidity correctives and source of Si, Ca, and Mg, improving the agronomic performance of soybean. Core Ideas: Silicate is more efficient in maintaining soil fertility compared to lime.Changes in soil fertility were observed up to a depth of 0.10 m after 24 months.Silicate increases silicon content in soybean leaf.Surface application of silicate increased soybean yield up to 43%.Soybean yield did not improve with lime. [ABSTRACT FROM AUTHOR]

In this study, CaMg 0.5 Co x Ni 0.5-x Si 2 O 6 (0.0 ≤ x ≤ 0.5) solid solutions with a diopside structure were prepared to reduce the cobalt and nickel amounts compared to M 2 SiO 4 or MgMSiO 4 (M = Co, Ni) compounds or CaCo x Ni 1-x Si 2 O 6 solid solutions. Colloidal gels were obtained by adding an ammonia aqueous solution to the suspensions of precursors in aqua until pH = 10. Diopside structure began to develop at 800 °C and at 1000–1200 °C crystallinity and pink colour of materials (x ≠ 0) are optimal. In both CaMg 0.5 Co x Ni 0.5-x Si 2 O 6 (0.0 ≤ x ≤ 0.5) and MgCo x Ni 1-x SiO 4 (0.0 ≤ x ≤ 1.0) solid solutions with diopside and olivine structures the position of the third transition of octahedral Co(II), 4T 1 → 4T 1 (P), is centred into the green absorption range and the observed colour is pink. A higher red amount in diopside than in olivine structure can be explained by the minor width of band of this third transition (minor distortion of octahedral M1 site) and shorter mean M1-O distances (M = Ni, Co). [Display omitted] [ABSTRACT FROM AUTHOR]

Here, we present a petrographic and microanalytical study of microinclusions in chromite from podiform chromitites hosted by the Sartohay ophiolitic mélange in west Junggar, northwestern China, to investigate the parental magma evolution and chromitite genesis. These silicate inclusions comprise olivine, enstatite, diopside, amphibole, and Na-phlogopite. Their morphological characteristics suggest that most inclusions crystallized directly from the captured melt, with a few anhydrous inclusions (olivines and pyroxenes) as solid silicates trapped during the chromite crystallization. Equilibrium pressure–temperature conditions of coexisting enstatite–diopside inclusions are 8.0–21.6 kbar, and 874–1048 °C. The high Na2O and TiO2 contents of hydrous minerals indicate that the parental magma of chromitites was hydrous and enriched in Mg, Na, Ca, and Ti. The calculated Al2O3 content and FeO/MgO ratio of the parental melts in equilibrium with chromite showed MORB affinity. However, the TiO2 values of parental melts, TiO2 contents of chromite, and estimated fO2 values for chromitites (1.3–2.0 log units above the FMQ buffer) evoked parental MORB-like tholeiitic melts. The composition of olivine inclusion was determined, and it was revealed that the primary melts of the Sartohay podiform chromitites had MgO contents of ~22.7 wt %. This aligns with the observed high magnesian signature in mineral inclusions (Fo = 96–98 in olivine, Mg# = 0.91–0.97 in diopside, and Mg# = 0.92–0.97 in enstatite). We propose that Sartohay podiform chromitites initially formed through the mixing/mingling of primary hydrous Mg-rich melt and the evolved MORB-like melt derived from the melt–peridotite reaction in the upper mantle. In this process, the continuous crystallization of chromite captured micro-silicate mineral inclusions, finally leading to the formation of the Sartohay podiform chromitites. [ABSTRACT FROM AUTHOR]

Tick Hill gold deposit is a unique gold mineralisation style in the Mary Kathleen Fold Belt in the Mount Isa Inlier. The gold at Tick Hill is generally pure without silver and was formed during two discrete metamorphic-deformation events (D1 and D3). Early gold was observed as inclusions or coarse grains hosted within D1 peak-metamorphic diopside, scapolite and hornblende from the garnet–biotite–hornblende (tschemakite)–plagioclase (andesine)–quartz assemblage. Late gold is closely associated with bismuth selenide, chlorite, albite, sericite and K-feldspar, and formed during D3. The syn-D1 garnet–plagioclase–hornblende–quartz–biotite assemblage was used to constrain the pressure and temperature (P–T) conditions of metamorphism and mineralisation using the garnet–plagioclase–hornblende–quartz barometer and the hornblende–plagioclase, garnet–biotite and garnet–hornblende thermometers. The results show that peak metamorphism at Tick Hill reached P–T conditions of 6.0–7.6 kbar and 720–760 °C. These P–T conditions together with gneissic and migmatisation textures recorded in different rock types at the Tick Hill area indicate that the peak metamorphism preserved in the area occurred at the amphibolite–granulite facies, compared with the amphibolite facies at the southern Mary Kathleen and Eastern Fold Belt. The D3 chlorite, which formed during stage 2 to stage 4 mineralisation events, displays a wide range of compositions reflecting a gradual retrograde temperature change from ∼380 °C to ∼130 °C. The pressures during D3 could not be reliably determined, but the presence of various Bi-selenides suggests that towards the waning stages of D3, the rocks may have been exhumed to a pressure less than 1 kbar. The 1790–1770 Ma D1 peak metamorphism at Tick Hill reached 6–7.6 kbar and 720–760 °C. The 1525–1520 Ma D3 hydrothermal mineralisation at Tick Hill Deposit occurred at temperatures between ∼380 °C and ∼130 °C. The main D3 gold accumulation episodes at Tick Hill occurred at temperatures ranging from ∼380 to 160 °C. [ABSTRACT FROM AUTHOR]

Neutron diffraction with magnesium isotope substitution, high energy x-ray diffraction, and 29Si, 27Al, and 25Mg solid-state nuclear magnetic resonance (NMR) spectroscopy were used to measure the structure of glassy diopside (CaMgSi2O6), enstatite (MgSiO3), and four (MgO)x(Al2O3)y(SiO2)1−x−y glasses, with x = 0.375 or 0.25 along the 50 mol. % silica tie-line (1 − x − y = 0.5) or with x = 0.3 or 0.2 along the 60 mol. % silica tie-line (1 − x − y = 0.6). The bound coherent neutron scattering length of the isotope 25Mg was remeasured, and the value of 3.720(12) fm was obtained from a Rietveld refinement of the powder diffraction patterns measured for crystalline 25MgO. The diffraction results for the glasses show a broad asymmetric distribution of Mg–O nearest-neighbors with a coordination number of 4.40(4) and 4.46(4) for the diopside and enstatite glasses, respectively. As magnesia is replaced by alumina along a tie-line with 50 or 60 mol. % silica, the Mg–O coordination number increases with the weighted bond distance as less Mg2+ ions adopt a network-modifying role and more of these ions adopt a predominantly charge-compensating role. 25Mg magic angle spinning (MAS) NMR results could not resolve the different coordination environments of Mg2+ under the employed field strength (14.1 T) and spinning rate (20 kHz). The results emphasize the power of neutron diffraction with isotope substitution to provide unambiguous site-specific information on the coordination environment of magnesium in disordered materials. [ABSTRACT FROM AUTHOR]

Due to the abundance of agrochemicals, feces, urine, and landfill leachates, nitrates ( NO 3 - ) are one of the most prevalent forms of inorganic pollutants in water bodies and groundwater. In this work, EC treatment was carried out in continuous flow with a Mg/Zn system for the treatment of a drinking water well near a landfill. The maximum efficiency of 93.15% was achieved at optimal operating conditions: current intensity of 0.6 A, flow of 2.9 mL/min and TRH of 86.81 min. In addition, 73% of silica was removed (from 65.05 to 17.76 mg/L), which interacts with magnesium and calcium to form silicates of both elements. EC is an efficient treatment technology with an operating cost of 2.65 US$/m3. In addition, Si causes interference in the EC system by prioritizing reactions with calcium and magnesium, and 72.69% Si was removed by EC. Finally, the inorganic ions were also significantly removed: 100% phosphates, 82.37% sulfates, 47% total hardness, and 42.28% chlorides. Conclusively, EC improved the water quality and thus minimized the health effects of consumers, and the drinking water studied in this work was used for the hydration of 212,500 L per day of milk formula for infant consumption and older adults. Highlights: Mg/Zn electrocoagulation was used for the treatment of drinking water polluted with nitrates. The maximum efficiency of 93.15% was achieved at 0.6 A, flow of 2.9 mL/min and TRH of 86.81 min. In addition, 73% of silica was removed from 65.05 to 17.76 mg/ L. EC is an efficient treatment technology with an operating cost of 2.65 US$/m3 EC improved the water quality minimizing the health effects of consumers. [ABSTRACT FROM AUTHOR]

This paper explores the connection between the H3BO3 flux concentration and the co-existence of Eu2+ and Eu3+ dopants within CaMgSi2O6 crystals (diopside). The samples were synthesised using a solid-state synthesis method under varying atmospheric conditions, including oxidative (air), neutral (N2), and reductive (H2/N2 mixture) environments. Additionally, some materials underwent chemical modification by partially substituting Si4+ with Al3+ ions acting as charge compensation defects stabilizing Eu3+ luminescence. Depending on the specific synthesis conditions, the materials predominantly displayed either the orangered luminescence of Eu3+ (under oxidising conditions) or the blue luminescence of Eu2+; however, the comprehensive results confirmed the co-existence of Eu3+/Eu2+ luminescence in both cases. This work shows that varying flux concentrations added during synthesis significantly affect the relative strength of Eu2+ and Eu3+ emissions in a manner dependent on the synthesis atmosphere. The emission of Eu2+ increases with a higher flux concentration in materials synthesised under oxidative and neutral atmospheres independent of the chemical modification. In contrast, for materials obtained under a reductive atmosphere, the changes in the Eu3+ emission intensity depended on the presence or absence of Al3+ ions namely the increase of flux increased the Eu3+ intensity in the case of unmodified materials and decreased in the Al-modified ones. All observed effects were qualitatively explained considering the double role of the flux in the studied system, which besides facilitating the diffusion of chemical species during synthesis acts as a charge compensating agent by creating B'Si centres stabilizing Eu3+ emission. [ABSTRACT FROM AUTHOR]

Nephrite is a very precious gemstone material. As a non-renewable resource, the discovery of new nephrite deposits and the study of the genesis of nephrite have aroused great interest. A new occurrence of nephrite known as Xinyu nephrite was discovered in Xinyu Country, Jiangxi province, China. Field investigations reveal that nephrite appears in a contact zone between the Mengshan composite granitic pluton and Permian carbonate rock. The carbonate rock is calcic marble that underwent diopsidization and tremolitization. Nephrites have a light yellow-green color, weak greasy luster, are slightly-translucent to translucent, and are fine-grained. Their refractive index (RI) ranges from 1.60 to 1.61, and their specific gravity (SG) value ranges from 2.90 to 2.91, falling within the range of nephrites from Xinjiang, China. Their Mohs hardness (Hm) ranges from 5.78 to 5.83. Petrographic observations and electron probe micro analyzer (EPMA) data indicated that analyzed nephrites mainly comprise tremolite, with minor diopside, calcite, quartz, and apatite. Tremolite has a ratio of Mg/(Mg + Fe2+) greater than 0.99. The tremolite grains show microscopic fibrous-felted and columnar textures. Scanning electron microscope (SEM) images show some tremolite fibers interwoven in different crystallographic orientations, and some arranged in parallel. Fourier transform infrared and Raman spectroscopy features reveal the bands of minerals typical for nephrite composition. The petrographic characteristics and geological background of the Mengshan area indicate that nephrite formed through a replacement of calcic marble, which differs from the two known types (D-type: dolomite-related; S-type: serpentinite-related). Mineral replacements were common in nephrite, including diopside by tremolite, calcite by tremolite, and recrystallization of coarse by fine tremolite grains. The discovery of Xinyu nephrite occurrence complements the resource and provides an updated case for the in-depth study of the diversity of nephrite deposits. [ABSTRACT FROM AUTHOR]

The technological trend toward "Wealth from Waste" is pertinent with the effective utilization of agricultural waste such as rice husk with properties such as availability, cost-effectiveness, durability, biodegradability, and environmentally friendly resources. In this article, nanodiopside concerning their wide application was synthesized using silica source from rice husk, calcium nitrate, and magnesium chloride. In this study, diopside nanoparticle was synthesized using rice husk ash obtained from agricultural waste. Then, the structure of nanodiopside was corroborated using FT-IR, EDX, TGA, FE-SEM, BET, XRD spectroscopic methods and the antibacterial properties of nanodiopside as well as its use as a nanocatalyst in Biginelli reaction and adsorbent to remove congo red dye was investigated. The experiment design method was used to optimize the Biginelli reaction conditions and to remove congo red dye. Finally, the antibacterial properties of nanodiopside were investigated. The results show that the heterogeneous diopside nanocatalyst can be reused up to 5 times. In addition to being economically and environmentally green and having good performance, nanodiopside reduces reaction time and the product has a good yield. In addition, recovery of the adsorbent shows that nanodiopside can be reused up to 4 times. Also, the study of adsorption isotherm and adsorption kinetics in optimal conditions showed that they correspond to the Langmuir and pseudo-second-order models, respectively. Furthermore, the data showed that nanodiopside has antibacterial properties. [ABSTRACT FROM AUTHOR]

Submarine mafic and relatively Na-poor alkaline rocks in the Outer Carpathians often contain aegirine, a sodic pyroxene usually found in diferentiated alkaline rocks. Its presence in rocks that are too basic and Na-poor for its conventional magmatic appearance is linked to sodic alteration of submarine alkaline rocks. Aegirine crystals grow on altered rims of diopside, commonly with crystallographic unconformity, suggesting that their growth was related to alteration and that aegirine does not represent a late stage of continuous clinopyroxene crystallization. The U-shaped REE patterns in the studied aegirine lack Eu anomaly, characteristic for aegirine from differentiated alkaline rocks. Therefore, the involvement of chemically more evolved magma is unlikely to have played any role in the formation of aegirine in ijolites and essexites. Formation of aegirine in submarine alkaline rocks may thus represent an alternative process to spilitization. However, this process is strongly limited by the availability of Fe3+ oxidized and mobilized by hydrothermal alteration, which may explain a relative scarcity of aegirine observed in submarine alkaline rocks compared to near-complete albitization of spilites, and its absence in high-MgO rocks (>10 wt%). Due to the blocking effect related to Fe3+ unavailability, ijolites, and essexites do not display significant Na enrichment. We posit that Na incorporated in aegirine was mainly sourced from the zeolitized interstitial glass. [ABSTRACT FROM AUTHOR]

Relevance. The use of natural diopside CaMgSi2O6 in the production of ceramic dielectrics was implemented at two enterprises in the Chelyabinsk region in 1985 on the basis of comprehensive studies of diopside rocks of the Southern Baikal region by the team of the Department of Silicate Technology of Tomsk Polytechnic University. Natural diopside was used as an additive to the charge of electrical porcelain. In addition, ceramic dielectrics with a diopside crystalline phase were manufactured for exploitation at the frequencies of 106 Hz. Currently, the need for ceramic dielectrics in Russia is covered by imports. Though, the development of new technologies for ceramic dielectrics from domestic raw materials is relevant. Aim. To develop an efficient technology for ceramic dielectrics with a diopside crystalline phase from natural low-iron diopside rocks. This technology includes the production of compacts of unfired products by moulding aqueous suspensions of compositions of nonplastic components. Object. The technology of ceramic dielectrics with a diopside crystalline phase, including the firing of compacts formed from aqueous suspensions of diopside concentrate compositions with perlite as flux. Methods. The suspension was obtained by grinding the components in an aqueous environment in a ball mill with uralite balls at humidity of 20±2%. Compressive and bending strength, electrical strength, dielectric constant of the samples were determined according to the SS 24409-80, water absorption was measured according to the SS 26093-84. X-ray phase analysis was carried out on a DRON-3M diffractometer (Burevestnik, Russia), structure analysis was implemented on a JSM 6000 electron microscope (Jeol, Japan). Results. A distinctive feature of the proposed technology is the use of nonplastic components only to prepare the suspension and the exclusion of clay components. This makes it possible to reduce the humidity of the castings and stabilize the formation of the ceramic structure during firing. The authors have obtained ceramic dielectric with a diopside content of 70±2 wt % by firing products molded at 1130–1150°C. The bending strength reached 85–90 MPa with an electrical strength of 35–38 k V/mm2.

The objective of this study was to determine the authorship, provenance, and technology of the mudejar enamelled tiles from the Olite Castle (northern Spain, 14th century). According to previous knowledge, Olite’s enamelled tiles had been manufactured in Manises (Valencia, Spain). The analysis of ceramic pastes revealed the existence of two different chemical compositions, suggesting the use of two different clay sources, probably one from the Tudela area, and another from the Tafalla–Olite area. Those probably made in the Tudela area stood out with a higher diopside (CaMgSi2O6) content. Those probably made in the Tafalla–Olite area stood out for their calcium-bearing minerals, such as calcite (CaCO3) or gehlenite (Ca2Al(AlSi)O7). On this basis, production in Manises has been ruled out. However, it is highly probable that the artisans of Manises would have led the production from Tudela. The study of the firing temperatures and composition of the enamels indicated that the production methods and materials used in Tafalla–Olite (800–850 °C) and Tudela (higher than 900 °C) were different, reflecting the influence of local and Manises artisans, respectively. In Olite tiles, enamel was applied following recipes from the 14th and 15th centuries.

A hydrogel-based wound dressing with desirable properties is necessary for achieving functional skin integrity post-injury. This study focuses on preparing a hydrogel using Alginate/Carboxymethyl cellulose (Alg/CMC) as a base material. To evaluate its regenerative effects on full-thickness wounds, diopside nanoparticles and Botulinum toxin A (BTX-A) were incorporated into the hydrogel along with chorion membrane. The diopside nanoparticles (DNPs) act as a proangiogenic factor, promoting proliferation and regulating inflammation, while the chorion membrane facilitates these processes. Additionally, BTX-A prevents scar formation and aids in wound closure. The nanoparticles and hydrogel were characterized using various techniques, and their cytocompatibility was assessed. In vivo studies and quantitative polymerase chain reaction analysis showed that wound area reduction was significant after two weeks of treatment with the Alg/CMC/ChNPs/DNPs/BTX-A hydrogel. Overall, this scaffold demonstrated potential for promoting tissue regeneration and new epithelization formation, making it a promising candidate for enhancing skin restoration in wound treatments. [ABSTRACT FROM AUTHOR]

Corrosion of calcium magnesium aluminum silicate (CMAS) severely affects the durability of thermal barrier coatings (TBCs). In this study, 8 wt% Y 2 O 3 partially stabilized ZrO 2 (8YSZ) coatings were prepared using atmospheric plasma spraying (APS) technique, and a Pt–Al film was magnetron-sputtered onto the surface of the YSZ coating (Pt–Al-YSZ) to enhance its resistance against CMAS. The results indicated that the Pt–Al-YSZ coating displayed superior non-wetting performance against CMAS, as well as stronger resistance to CMAS corrosion. The results evidenced by Raman spectra and X-ray diffraction showed that phase transformation was smaller and corrosion depth was lower after CMAS corrosion at 1250 °C for 2 h. The thermal cycling test was also performed. The result demonstrated that the Pt–Al coating did not have a negative impact on the thermal cycling life of the YSZ TBCs. However, platinum tended to soften at high temperatures and became easily penetrated by molten CMAS. Therefore, it is necessary to further improve the strength of platinum layer to fully utilize its protective effect against CMAS attack. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations were performed on CaO-MgO-Al2O3-SiO2 (CMAS) diopside glass ceramics (GCs) to study the effect of nanocrystal on glass and the effect of chemical composition on mechanical properties. Under tensile loading, the GCs demonstrated that the strength lay between its glass and ceramic counterparts and maintained considerable ductility. Moreover, high Mg/Ca ion ratios are conductive to both the strength and ductility of GCs. In addition, Al ions should be avoided as far as possible since they would promote fracture. After analyzing the shear strain and displacement vector map for ion structures, we found that the presence of nanocrystal in glass changes the original deformation pattern and led to the deformation concentration surrounding the nanocrystal. A high Mg/Ca ion ratio would make the deformation more homogeneous, while a high Ca/Mg ion ratio would aggregate the deformation in the glass region near the nanocrystal. The existence of Al ions near the interface between glass and crystal would promote the formation of voids. [ABSTRACT FROM AUTHOR]

Electrolytic manganese residue (EMR) is toxic industrial solid waste. Electrolytic manganese enterprises have established a desulfurization and sulfuric acid production process to address its storage risks leaving desulfurized EMR (DEMR). In this study, DEMR was used as a raw material to prepare glass-ceramics. A method of melting and one-stage heat treatment was used to realize controlled crystallization of diopside, with calcium fluoride sludge (FS) as a nucleating agent. The impact of CaF 2 on the glass network structure, as well as on the microstructure and performance of the glass-ceramics, are discussed. CaF 2 can greatly improve the nucleation ability of glass precursors. When the addition of FS is small, the phase transition of glass is dominated by the diffusion of atoms and growth of diopside, forming dendritic crystals. When introducing more FS, the glass-ceramics form smaller island-shaped crystals due to many nucleation sites. The prepared glass-ceramics show excellent mechanical properties and chemical stability. Its hardness exceeds 6.5 GPa, with bending strength over 110 MPa. The acid resistance of glass-ceramics is higher than 99.5%, and the toxic metals in the raw materials are stable solidified. This study perfects the technology of EMR desulfurization pretreatment, which provides an effective graded recycling approach for EMR. [ABSTRACT FROM AUTHOR]

Sealants based on glass have been widely used in solid oxide fuel cell (SOFC), and have shown considerable potentials due to their low leakage rate. We report a tape of sealant made by adding different contents of diopside into silicate glass, which has a coefficient of thermal expansion (CTE) matching that of adjacent components. Glass-diopside composite sealing material can block the diffusion of chromium from interconnect has been studied. The structure of the 20 wt% diopside doped silicate glass is stable at high temperatures with leakage rates less than 0.004 sccm∙cm−1, and no crystal except for diopside is found in XRD analysis after heating at 750 °C for 100 h. Excellent interface compatibility between the sealant and SUS430 interconnect was proved by SEM at 750 °C for 100 h. The above results prove the possibility of using glass-diopside composite sealing material for SOFC applications. • A composite sealing material is designed by doping diopside into glass. • The CTE of composite sealing material matches that of the adjacent components. • The composite sealing material doped with 20 wt% shows good sealing properties. • The designed composite sealing material has excellent resistance to Cr diffusion. [ABSTRACT FROM AUTHOR]

Nephrite jade is of wide interest, not only for its value as a highly valued precious stone, but also for its significance in tracing geological and petrological processes. Here, we report the first discovery of a nephrite deposit in Africa, located in Somaliland. Field investigations revealed that two open nephrite pits at Goodieood and Laasmacaane are composed of a series of discontinuous vein-shaped nephrite bodies stretching for ~2 km and de- fining a nephrite belt. Dolomitic marble and epidote-amphibole are the major rock types in this nephrite belt. Most of the nephrites show grayish green color, while a few are grayish white to light-grayish green, with an occasional brownish rind mainly in nephrite gravels from the secondary deposits. The nephrite is composed of tremolite and actinolite with minor diopside, pargasite, edenite, and apatite. Most nephrites display fine fiber microstructures, and the tremolite-actinolite aggregates show crystallographic preferred orientation. Parallel to the nephrite bodies, epidote-amphibole rocks appear as a metasomatic dark-colored boundary zone, composed mainly of actinolite-tremolite, epidote, and titanite with minor rutile, pargasite, edenite, diopside, and zircon. The dolomitic marble displays dolomite replacement partially by antigorite. Textural observations suggest a sequence from Na-, Al-, and Fe-rich toward Mg-rich compositions, leading to the possibility of prospecting for white nephrite. The various features suggest that the deposit belongs to a fluorine-bearing Ca-Fe-P fluid-dominant skarn. This deposit is estimated to have more than 1000 tons of nephrite jade reserves and has important significance for the exploration for more economic nephrite deposits in Africa, South America, and even Antarctica, as well as potentially important archaeological implications in establishing a connection between the nephrite jades and materials for the Hargeisan lithic industries, as part of the social development in eastern Africa. Comparison with a typical white nephrite deposit in Saidikulam provides insights into the formation of white and nonwhite nephrites. [ABSTRACT FROM AUTHOR]

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Activated carbon from rice husk ash (AC-RH) and hazelnut husks (AC-HH) modified by Diopside (AC-RH/Diop, AC-HH/Diop) composites were synthesised and applied for the adsorption of Copper and Methylene blue from industrial effluents. Diopside was provided by the sol-gel method and activated carbon was prepared from rice husk ash and hazelnut husks. The formation of AC/Diop composites was characterised by FT-IR, FESEM, BET, and XRD analyses. Effects of pH, amount of adsorbent, and contact time at 10 mg L−1 of Copper and Methylene blue on removal percentage were studied by Box Behnken design (BBD). Optimal conditions for maximum Copper and MB by AC/Diop adsorbent (95.54% and 99.42%, respectively) were as follows: (pH = 5.45, 7.35) (adsorbent amount: 0.10, 0.45 g), and (contact time: 9.56, 13.49 min) in 20 mL of 10 mg L−1 of pollutants concentration, respectively. In addition, the adsorption kinetics, thermodynamics, and isotherms were examined. Adsorption isotherms (qmax: 184.25 and 289.51 mg g−1 for Copper and MB, respectively) and kinetics were demonstrated that the sorption processes were better described by the Langmuir and pseudo-second-order equation. [ABSTRACT FROM AUTHOR]

This paper describes the characteristics of akermanite-gehlenite and diopside bioceramics derived from the CaO-MgO-Al2O3-SiO2 system as a potential bone substitute material. The akermanite-gehlenite and diopside bioceramics were synthesised for 4 h at 500 rpm via the wet mechanochemical process. The resultant powder was sintered at 1050 and 1150 °C for 1 h to obtain the akermanite-gehlenite and diopside bioceramics. The bioceramic's microstructural, physical, and mechanical properties were investigated comparatively. XRD diffraction, FTIR and scanning electron microscopy, with energy dispersive spectroscopy (SEM-EDS) analysis, were conducted to characterise the samples. The bioceramic samples' linear shrinkage, density, porosity, and water contact angle were analysed to determine their physical properties. The mechanical properties of the samples were determined using compressive tests before and after undergoing in vitro bioactivity. The in vitro bioactivity of the bioceramic was investigated by analysing its apatite-forming ability in a simulated body fluid (SBF) at 37 °C. XRD patterns, SEM micrographs, and FTIR spectra for pellets sintered at 1050 °C indicated the presence of apatite particles on their surfaces. The pellets' compressive strength before being immersed in SBF ranged between 24.42 ± 1.5 and 24.93 ± 1.7 MPa. The compressive strength of the pellets noticeably decreased to 34.4% and 40.7% after 14 days of immersion in SBF. In conclusion, the akermanite-gehlenite bioceramic prepared using the wet mechanochemical method can potentially become a bone substitute. [ABSTRACT FROM AUTHOR]

The production of cost-effective and eco-friendly transparent ceramic glazes by incorporating pristine waste and eliminating frit preparation was intended to be applied on porcelain bodies. The effect of sintering temperature (950—1150 °C) and waste content (0–15 wt.%) on glazes' phase evolution and optical properties was investigated. At 950 °C, neat glaze consisted of crystalline silica, whereas the waste addition into the glaze composition formed crystalline diopside. Gloss (60°) values generally increased above 950 °C due to the amorphization of crystalline phases; however, sintering at 1150 °C caused a crawling defect for the neat glaze that resulted in gloss reduction. Also, high waste ratios (> 5 wt.%) declined gloss too because of the raised diopside content. The decreasing sintering temperature and the waste ratio higher than 5 wt.% led to higher whiteness due to the white color of the crystalline diopside. Briefly, the addition of 5 wt.% waste to the transparent ceramic glaze recipe provided the highest gloss (77.8) and whiteness (90.2) at 1150 °C, which are higher than even maximum values of neat glaze (40.1 and 88.9) obtained at 1050 °C. Therefore, porcelain bodies with transparent ceramic glazes, produced by the proposed cost-effective and eco-friendly method, carry the potential to be used in various fields as porcelain dinnerware, sanitaryware, and tiles, [ABSTRACT FROM AUTHOR]

Dokhan region is located in the west of Nobaran (Saveh), between Urumieh-Dokhtar and SanandajSirjan zones. In this study, the geochemistry of whole rock and the chemistry of clinopyroxene, olivine and nepheline minerals in Dokhan Quaternary volcanic rocks have been studied. From Petrographic aspect, the studied rocks are mostly melanephelinite and olivine melanephelinite. The chemical composition of rocks include foidite, tephrite and basanite. These rocks are relatively rich in CaO and MgO and poor in SiO2 and Al2O3. Their olivine is chrysolite and clinopyroxene is diopside. The parent magma of these rocks is derived from a metasomatized garnet lherzolite mantle that is somewhat contaminated with the continental lithosphere. Temperature-pressure measurement of these rocks using the composition of minerals shows the temperature of 1200° C to 1250 ° C and pressure of 5 to 10 Kb. These rocks are probably formed in the intercontinental environment after the subduction of Neotethys and the collision of the Africa-Arabia and Eurasian continents. [ABSTRACT FROM AUTHOR]

The recently discovered Mida nephrite deposit, located in the East Kunlun Mountains, Qiemo County, Xinjiang, Northwest China, contains new types of white and greenish white nephrite formed by limestone replacement, which shows microstructures, macroscopic features and country rocks typologies that are quite different from those of the other deposits along the Kunlun–Altyn Tagh Mountains. The gemological and mineralogical characteristics of Mida nephrite are presented here. These nephrites show an ivory white color and a porcelain-like appearance, with semitranslucent-to-opaque transparency and a porcelain-to-greasy luster. Petrographic study, electron probe microanalysis (EPMA) data and scanning electron microscopy (SEM) images have indicated that the nephrite is composed of tremolite, accompanied by minor quartz, calcite and diopside. Tremolite aggregates have shown different textures, like flaky, granular, fibrous–felted, bundle, radial and metasomatic relict textures. Quartz has appeared in granular or disseminated form, dispersed in the tremolite matrix. Calcite has shown a metasomatic relict texture in the white nephrite samples. Diopside has shown euhedral grains, with some distributed with a certain geometric appearance. Based on our observations, it is suggested that the quartz in the nephrite originated from Si-rich hydrothermal fluids. We propose that the substantial size difference of mineral grains, together with uncompacted grains with inter-particle pores, are the main reasons for the internal reflection and refraction under transmitted light, which allow less transmitted light to pass through the nephrite body and generate the appearance of a semitranslucent-to-opaque transparency, ivory white color and porcelain luster. Our study has unveiled that the Mida nephrite is not typical of the two known types (D-type: dolomite-related; S-type: serpentinite-related) and is overlapped by quartz grains dispersed throughout the less compact tremolite matrix. These observations would help set it apart from the majority of nephrite jades found in the Kunlun Mountains region and provide valuable insights for enhancing comprehension of the diversity of the nephrite deposits. [ABSTRACT FROM AUTHOR]

Bioactive glasses in the CaO–MgO–Na2O–P2O5–SiO2–CaF2 system are highly promising materials for bone and dental restorative applications. Furthermore, if thermally treated, they can crystallize into diopside–fluorapatite–wollastonite glass-ceramics (GCs), which exhibit appealing properties in terms of mechanical behaviour and overall bone-regenerative potential. In this review, we describe and critically discuss the genesis, development, properties and applications of bioactive glass “1d” and its relevant GC derivative products, which can be considered a good example of success cases in this class of SiO2/CaO-based biocompatible materials. Bioactive glass 1d can be produced by melt-quenching in the form of powder or monolithic pieces, and was also used to prepare injectable pastes and three-dimensional porous scaffolds. Over the past 15 years, it was investigated by the authors of this article in a number of in vitro, in vivo (with animals) and clinical studies, proving to be a great option for hard tissue engineering applications.

ABSTRACTMgO was added to the SiO2-Al2O3-CaO-ZrO2-based glaze to produce a high-hardness glaze by forming a composite crystal phase. The effects of MgO addition on the surface properties of the glaze were analyzed through crystal phase and microstructural investigations, and the whiteness, roughness, gloss, wear rate, and hardness were measured. When the amount of added MgO increased by 2.20 wt% or more, the diopside (MgCaSi2O6) crystal phase was observed via X-ray diffraction (XRD) and scanning electron microscopy (SEM), in addition to the zircon (ZrSiO4) crystal phase. All samples exhibited high whiteness and the surface roughness increased with increasing MgO content. At the same time, the gloss decreased significantly, resulting in a matte. The Vickers hardness test results of the glazed surface indicated high hardness values of 6.23–7.07 GPa with increased amounts of MgO.

We report new experimental data from ultrabasic basanite and ultrabasic tephrite as starting material compositions in the 1350°C to 1000°C temperature range. Crystallization experiments under low- to high-pressure (0.5–2.0 GPa) were carried out under reduced conditions (≈CCO buffer), while one-atmosphere, anhydrous, experiments were performed ranging from reduced to oxidized conditions (−2 ≤ ∆QFM ≤ +2). The results highlight the ƒO2 role on the silica saturation of the alkali liquids differentiated from these primary ultrabasic magmas, on the mineral assemblage, and its composition. The liquid lines of descent (LLDs) from basanite are sodic and strongly SiO2 undersaturated, whereas from tephrite, the LLDs are sodic-potassic/potassic for both weakly SiO2-undersaturated and SiO2-saturated compositions, being more silica saturated under oxidized conditions. At the lowest temperature experiments, the percentage of liquid remaining is significantly higher in the basanite-derived products (ca. 35 wt.%) than in tephrite, indicating that the equivalent magmas are more prone to produce larger quantities of evolved melts. The best obtained Fe–Mg olivine/melt and clinopyroxene/melt exchange coefficients for these alkali compositions considering the new and available data are |${K_D}_{Fe^{2+}- Mg}^{Ol- Alkali\ melt}=0.285\pm 0.014$| and |${K_D}_{Fe^{2+}- Mg}^{Cpx- Alkali\ melt}=0.245\pm 0.008$|⁠ , slightly lower than those observed in tholeiitic melts. Clinopyroxene compositions are Ti–Al-rich and Si-poor as compared with common clinopyroxenes in subalkali systems. We suggest that Ti should be allocated in the tetrahedral sites substituting for Si and that its contents are inversely correlated with pressure. Our results allow a simple new barometer based on clinopyroxene-only compositions, as follows: $$ P\left(\pm 0.16\ GPa,1\sigma \right)=16.028\left(\pm 1.042\right) Na-6.715\left(\pm 0.727\right)\frac{Ti}{Ti+ Al(t)}+0.494\left(\pm 0.441\right) Si+0.144\left(\pm 0.079\right) $$ where Na, Ti, Al(t), and Si are molar proportions relative to 6O. This formulation accounts for the jadeite (NaAlSi2O6) component, herein computed from the Na contents, corrected for the Ti-diopside (CaMgTi2O6) component in clinopyroxene and also considers the evolutionary trend from Mg-augite to ferroan diopside. It applies to alkali ultrabasic to intermediate compositions in the examined P–T–ƒO2 range, resulting in more accurate estimates than the available calibrations. The MgO-in-melt thermometer was optimized for the studied compositions at one-atmosphere pressure and anhydrous conditions, as follows: $$ T\ \left(\pm 5{}^{\circ}C,1\sigma \right)=27.35\left(\pm 0.65\right)\ \big({MgO}^{liq}\big)+984\left(\pm 4\right) $$ which provides much more reliable liquidus temperatures for these alkali systems. Given data restriction, this formulation may be expanded to include the pressure effects for relatively low-H2O (< 3 wt.%) systems as: $$ T\ \left(\pm 20{}^{\circ}C,1\sigma \right)=27.35\left(\pm 0.65\right)\big({MgO}^{liq}\big)+80.20\left(\pm 5.50\right)P(GPa)+981\left(\pm 4\right) $$ [ABSTRACT FROM AUTHOR]

Graphite usually occurs in mineral/rock associations in the form of solid inclusions and plays an important role in tracing regional metamorphic degree, ore-forming temperature, fluid evolution, as well as the deep carbon cycle of the Earth. In this study, we investigate the placer black nephrite jade where the co-occurrence of abundant graphite inclusions and jade remains extraordinary. By employing petrographic, mineral-chemical, and Raman spectroscopic methods, we characterize the textures and crystallinity of graphite inclusions that exist in nephrite jade. EPMA and petrological data indicate that the main constituents of black jade are tremolite and graphite, with minor phases of diopside, calcite, dolomite, epidote, and apatite. Micro-Raman spectroscopic thermometry of carbonaceous material shows that most of the formation temperatures of graphite inclusions are between 378 and 556 °C, and only a few temperatures may be above 650 °C, indicating that graphite inclusions were formed at medium- to high-temperature metamorphic facies. The petrologic and spectral investigations of graphite inclusions in these nephrite jade samples show major metamorphic signatures with mixed features associated with fluid precipitation. Our results allow us to propose that primary nephrite jade was formed under multi-stage tectonic evolution conditions, and regional temperatures were predominately driven by the late continent–continent collision, while the ore-controlling temperatures of nephrite jade formation were found in a medium- to high-temperature environment. [ABSTRACT FROM AUTHOR]

An earthquake-resistant brick of M150–M175 grade is obtained from a low-alumina (Al2O3) < 15%) fusible clay and a high-alumina (Al2O3 > 60%) nanotechnogenic aluminoalkaline sludge. The use of the aluminoalkaline sludge even in the amount of 20% enhances the performance characteristics of the ceramic brick to the M125 grade; the optimum amount of the aluminoalkaline sludge to be used is at most 30%. The crystallization of hematite, anorthite, diopside, and crystobalite is observed when the temperature of burning of the ceramic samples is 1000°C. The increase in the burning temperature to 1050°C results in no specific changes, except for an increase in the content of crystobalite, anorthite, glass phase, and diopside. A further increase in the temperature of burning of the aseismic brick to 1100°C favors the emergence of mullite, which increases the main physicomechanical and chemical characteristics of the aseismic brick. [ABSTRACT FROM AUTHOR]

Numerous empirical and experimental studies have documented the consumption of orthopyroxene and production of clinopyroxene in mantle peridotite during carbonatite metasomatism, whereas little attention has been paid to whether and how olivine is compositionally modified through the same process of carbonatite metasomatism. Here, we present the discovery of well-preserved reaction features in olivine from typical calciocarbonatites from Sri Lanka. The olivine grains experienced serpentinization along the cracks and in their rims and are generally surrounded outwardly by serpentine, tremolite and diopside zones. The inner serpentine zone is dominated by serpentine with tiny magnetite, whereas the mantle tremolite zone is characterized by euhedral tremolite and intergrowth of dolomite with small amounts of serpentine relics and diopside. The outer diopside zone shows spongy texture and commonly encloses olivine, serpentine, tremolite and dolomite, which are also observed in interstitial diopside grains in the carbonatites. Compositional profile analyses reveal that these olivine grains display decreasing FeO and increasing MgO contents and thus elevating Fo values from their cores to the reaction rims, while the serpentine inherits compositions from the olivine. Elemental mapping images demonstrate outward diffusion of Si and Mg in the serpentine zones and contribution of Ca from carbonatite melts during tremolite formation. Further interaction with carbonatite melts produced Si- and Mg-poor and Ca-rich diopside relative to the reactant tremolite. These observations suggest that the interaction with carbonatite melts first transformed olivine to diopside through serpentinization, followed by tremolitization. The diopside formed through olivine-carbonatite melt interaction is anomalously depleted in Na and Al and enriched in Ca, which are distinct from those generated in interactions between orthopyroxene and both carbonatite and silicate melts. This implies that for the first time some wehrlites and clinopyroxenites in the mantle might originate from intense interaction between peridotites (including dunite) and carbonatite melts. This mechanism can be invoked to explain the formation of other global occurrences of wehrlite and clinopyroxenite suites. [ABSTRACT FROM AUTHOR]

In marine environment, thermal barrier coatings (TBCs) face coupling corrosion of calcium magnesium aluminum silicate (CMAS) and molten salt leading to premature failure. In this study, microstructure evolution of TBCs resulting from CMAS + NaVO 3 (CN) coupling corrosion is investigated, and a corrosion protection method based on laser glazing is proposed. TBC degradation by the CN coupling corrosion is mainly due to the high penetration ability of the melt. Laser glazed TBCs have improved resistance to the coupling corrosion, however, the vertical cracks in the glazed layer provide paths for melt penetration. TBCs with double laser-glazed layer are designed, with vertical cracks in the glazed layer being bifurcated and staggered, which could largely suppress CN melt infiltration, and also exhibits excellent phase and microstructure stability in the coupling corrosion condition. This type of laser modified TBC is confirmed to be attractive against the coupling corrosion. [ABSTRACT FROM AUTHOR]

In alkaline-ultrabasic rocks from North-Western part of the Ukrainian Shield pyroxenes are predominantly presented by diopsides with various contents of Cr2O3 (up to 2.4%, chrome diopside), Na2O and Al2O3 (to 7.6%). But correlation between contents of Al2O3 and Na2O generally is absent except two samples. Natrium goes into composition of acmite, cosmochlore or jadeite minals. In pyroxenes with high Al2O3 aluminum goes into tetrahedral positions. Pyroxenes (include aegirines) with increase TiO2 content (to 1.5%) rarely occur. Aegirine and intermediate between latter and diopside aegirine-diopsides have limited development. They could crystallize in at least eroded dike rocks that consist of melteigite porphyres with high agpaicity ((Na+K)/Al ≈ 1). Majority of studied pyroxenes crystallized from magnesian (to 22% MgO) primitive alkaline-ultrabasic melts in hypabyssal intrusions. It is supposed that limited amount of intermediate aegirine-diopsides or a gap in series diopside-aegirine is caused by the crystallization of alkaline and subalkaline amphiboles. [ABSTRACT FROM AUTHOR]

Bioactive diopside (CaMgSi2O6) nanoparticles have recently gained potential usefulness as bone replacement materials and nano vehicles for delivering therapeutics. The structural characteristics of this ceramic have found to be a key factor in bone bonding ability. To attain the desired product for 100% clinical success, it is important to realize the relationship between structure and biological activity. Synthesis of these nanoparticles via the solid-state method has been regarded as a low-cost and easy process in large-scale, but time consuming reactions and high temperature (≈ 1400 °C) are required. On the other side, the wet chemistry can overcome these drawbacks, whereas the presence of byproducts in the final powder has limited this method in large-scale production. The present document has represented a simple, fast and one-pot sol–gel approach for the synthesis of highly pure diopside nano-powders (< 20 nm) by using not-expensive precursors. Calcination of the obtained powder has been conducted at various temperatures (700, 1000 and 1200 °C). The physicochemical and microstructural properties of the products have been characterized by XRD, FTIR, FESEM and TEM. Moreover, the impact of the crystallinity on the bioactivity, drug loading capacity and drug release behavior of the synthesized nanoparticles have been investigated here for the first time. The in-vitro bioactivity results of the prepared diopside samples in a simulated body fluid (SBF) at 37 °C revealed the higher capability of the sintered sample to deposit calcium phosphate, compared with the amorphous one. High quantity of gentamicin (around 10 µg) could attach to the surface of 1 miligram of the sintered diopside during the early stages of contact (3 h), suggesting the potential use of diopside as a new class of nano-vehicles for antibiotics. The release behavior indicated a sustained release of gentamicin (80%) after 24 h. In conclusion, diopside nanoparticles can be a promising candidate as a drug-vehicle for bone filling, implant coating or bone cement applications. [ABSTRACT FROM AUTHOR]

Acid sulfate soil characterized by pyrite (FeS2) which produces high acidity (soil pH < 3.5) and release high amount of Al3+ and Fe2+. Application of 4 t ha-1 Ground Magnesium Limestone (GML), is a common rate used for acid sulfate soil by the rice farmers in Malaysia. Therefore, this study was conducted to evaluate the integral effect of ground magnesium limestone (GML) and calcium silicate and to determine the optimal combination on acid sulfate soils in Malaysia. The acid sulfate soils were incubated under the submerged condition for 120 days with GML (0, 2, 4, 6 t ha-1) in combination with calcium silicate (0, 1, 2, 3 t ha-1) arranged in a Completely Randomized Design (CRD). The soil was sampled after 30, 60, 90 and 120 days of incubation and analyzed for soil pH, exchangeable Al, Ca, Mg, K and available Si. A total of 2 out of 16 combinations met the desired soil requirement for rice cultivation. The desired chemical soil characteristics for rice cultivation are soil pH > 4, exchangeable Al < 2 cmolc Kg-1, exchangeable Ca > 2 cmolc kg-1, exchangeable Mg > 1 cmolc kg-1 and Si content > 43 mg kg-1. The combinations are i) 2 t ha-1 calcium silicate + 2 t ha-1 GML, and ii) 3 t ha-1 calcium silicate + 2 t ha-1 GML, respectively. These combination rates met the desired requirement of soil chemical characteristics for rice cultivation. Soil acidity was reduced by a gradual release of Ca2+ and SiO32- from calcium silicate continuously filling the exchange sites and reducing the potential of extra (free) H+ availability in the soil system. Combination of calcium silicate and GML, shows the ameliorative effect with; i) release of Ca, ii) binding of Al3+ making it inert Al-hydroxides and, iii) bind H+ to produce water molecules. [ABSTRACT FROM AUTHOR]

MgO was added to the SiO2-Al2O3-CaO-ZrO2-based glaze to produce a high-hardness glaze by forming a composite crystal phase. The effects of MgO addition on the surface properties of the glaze were analyzed through crystal phase and microstructural investigations, and the whiteness, roughness, gloss, wear rate, and hardness were measured. When the amount of added MgO increased by 2.20 wt% or more, the diopside (MgCaSi2O6) crystal phase was observed via X-ray diffraction (XRD) and scanning electron microscopy (SEM), in addition to the zircon (ZrSiO4) crystal phase. All samples exhibited high whiteness and the surface roughness increased with increasing MgO content. At the same time, the gloss decreased significantly, resulting in a matte. The Vickers hardness test results of the glazed surface indicated high hardness values of 6.23–7.07 GPa with increased amounts of MgO. [ABSTRACT FROM AUTHOR]