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The chlorination of oxides of major concern in cassiterite concentrate with various chlorinating agents is investigated in light of their thermodynamic feasibilities to extract and recover their valuable metal components. Mechanisms responsible for the processes and their Gibbs free energy changes as a function of temperature to selectively separate and/or recover the metal(s) of interest and unwanted ones as their metallic chlorides are identified. Attention is given to gaseous (Cl2 and Cl2 + CO mixture) and solid (CaCl2 and MgCl2) chlorine sources, from which Cl2 + CO shows no reaction selectivity for any of the oxides but a feasible metal chloride formation for all. Chlorine gas (Cl2), on the other hand, could selectively form chlorides with metals of +2 oxidation state in their oxides, leaving those of high oxidation state unreacted. MgCl2, unlike CaCl2, is found capable of producing calcium, ferrous, and stannic chloride from their metallic oxides with enhanced reaction tendencies in the presence of silicon dioxide (SiO2). An overall study of the thermodynamic feasibility of all chlorine sources looked at alongside operational and environmental viabilities suitably suggests MgCl2 for a selective extraction of the valuable metal components in a cassiterite concentrate, in which case, moderate temperatures seem promising. [ABSTRACT FROM AUTHOR]

The high-pressure (HP) migmatitic paragneiss of the Beni Bousera metamorphic unit (BBMU) from the Beni Bousera Massif underwent granulite-facies metamorphism. They mainly consist of garnet, biotite, kyanite, sillimanite, cordierite, spinel, quartz, plagioclase, K-feldspar, rutile, ilmenite and graphite. These minerals form a sequence of metamorphic assemblages corresponding to five metamorphic events (M1, M2, M3, M4, and M5). The first three events correspond to a latest Carboniferous-earliest Permian metamorphic evolution, while the last two are retrograde and Alpine in age. The p-T conditions of these metamorphic events were estimated using pseudosection calculations in the MnNCKFMASTHO system. Following prograde stage conditions of 9.3–10.9 kbar and 630–665°C (M1 stage), the p-T evolution culminates in melting of the paragneiss which occurred mainly at HP conditions, within the kyanite stability field, at 11.8–14.2 kbar and 820–845°C (M2 pressure-peak); anatexis then continued at high to medium pressure (HMP), within the sillimanite stability field, at 9.9–11 Kbar and 840–860°C (M3 thermal-peak), accompanied by the production of very small proportions of melt. The prograde p-T segment of the inferred clockwise path is characterized by a pressurization related to a post-Variscan collisional event triggered by the closure of the Paleotethys Ocean, and is followed by the exhumation of the granulitic unit to mid-crustal depth, with slight coeval heating. The retrograde Alpine evolution is coeval with the final exhumation of the migmatitic paragneiss and underlying peridotites during back-arc extension related to the westward retreat of the Alpine subduction. It occurred under sub-solidus conditions from 9.5–10.7 kbar and 818–848°C (M4) to 4.9–5.85 kbar and 710–785°C (M5) and corresponds to a near-isothermal and strongly decompressive metamorphic evolution (ΔP ≈ 5 Kbar). [ABSTRACT FROM AUTHOR]

Lanthanides and actinides are emerging contaminants, but little is known about their uptake and distribution by plants and their interactions in the rhizosphere. To better understand the fate of these metals in plants, the bioassociation of 2, 20 and 200 µM Eu(III) by five hydroponically grown crops endemic to Europe was assessed. The metal's concentration and its speciation were monitored by inductively coupled plasma mass spectrometry and laser spectroscopy, whereas root exudation was investigated by chromatographic methods. It has been shown, that Eu(III) bioassociation is a two-stage process, involving rapid biosorption followed by accumulation in root tissue and distribution to the stem and leaves. Within 96 h of exposure time, the plant induces a change of Eu(III) speciation in the liquid medium, from a predominant Eu(III)aquo species, as calculated by thermodynamic modelling, to a species with longer luminescence lifetime. Root exudates such as citric, malic, and fumaric acid were identified in the cultivation medium and affect Eu(III) speciation in solution, as was shown by a change in the thermodynamic model. These results contribute to a comprehensive understanding of the fate of lanthanides in the biosphere and provide a basis for further investigations with the chemical analogues Cm(III) and Am(III). [ABSTRACT FROM AUTHOR]

[Display omitted] • Baikalian cycle in N Baidrag, Mongolia, constrained by P–T & monazite ages. • Progressively thickened continental back-arc beneath shortened supracrustal unit. • Diachronous burial of distal (570–565 Ma) & proximal (545–538 Ma) units. • Contrasting 18 & 28°C/km gradients at 570–560 Ma explained by back-arc thickening. • Contrasting 19 & 29°C/km gradients at 542–538 Ma are due to orogenic core exhumation. In-situ monazite geochronology with P–T modelling of Barrovian-type metasediments was carried in the Burd Gol zone, NE Baidrag block. The P–T peak recorded by Grt−Sil migmatite is ∼780 °C, 7.5 kbar; by Grt–St–Ky gneiss ∼690 °C, 10 kbar and by Grt schist ∼590 °C, 8 kbar. Monazite ages related to metamorphic peaks indicate diachronous burial events, c. 570–565 Ma for the Grt–Sil migmatite, c. 565–560 Ma for the Grt–St–Ky gneiss, and at c. 538 Ma for the Grt schist. Tonian Grt–St schist recorded new monazite crystallization at c. 546–543 Ma. By c. 545–542 Ma, the Grt–Sil migmatite and Grt–St–Ky gneiss experienced exhumation to ∼5 kbar, while the Grt schist underwent burial. Further exhumation is dated by xenotime, rutile and monazite alteration down to c. 515 Ma. The data suggest a prolonged orogenic cycle initiated by burial of distal orogenic core to the depths of ∼35 km at c. 570–565 Ma while the proximal continental margin was buried at c. 545–538 Ma. The higher-grade core was subsequently exhumed to the middle crust at c. 550–540 Ma and the orogenic activity ceased at c. 515 Ma. The difference in metamorphic gradients around 570–560 Ma, with ∼27–28 °C/km for the Grt–Sil migmatite and ∼18–19 °C/km for the Grt–St–Ky gneiss suggests lateral variations as a result of localized juxtaposition of migmatite-magmatite lower-middle crust with colder regions. A new model shows the Burd Gol zone as a progressively thickened and exhumed continental back-arc system beneath the supracrustal 590–570 Ma continental back-arc represented by the adjacent Ulziit Gol unit. The data provide important constraint on the timing and mechanisms of orogenic Baikal cycle at the margin of the Siberian Craton. [ABSTRACT FROM AUTHOR]

Marine clay, a common waste product abundantly available in coastal regions, can serve as an alternative silica source after activation due to its pozzolanic reactivity. In this study, a binder comprising reactive MgO cement and thermally activated marine clay (AMC) was developed. It was found that the developed MgO-AMC binder with a mass ratio of MgO to AMC of 0.4 to 0.6 achieved a 28-day compressive strength of 20.4 MPa under ambient curing. Through accelerated carbonation curing, the highest 28-day compressive strength increased by 45%, and the highest carbon sequestration ratio reached 11.8%. The phase evolution and microstructural development of hydrated/carbonated binder were comprehensively investigated by TG-IR, XRD, NMR, and SEM-EDS. In addition, thermodynamic modelling was performed to further understand the phase assemblage of the hydrated binder, and indicated that M-A-S-H phase was thermodynamically more stable in the developed binder. [ABSTRACT FROM AUTHOR]

Integrated experimental and thermodynamic modeling study was undertaken to characterize the effect of Al, Ca and Zn on the partitioning of elements between the slag, matte and metal phases in the Pb–Fe–O–S–Si-(Al), (-Ca), and (-Zn) systems in equilibrium with tridymite at 1100–1200 °C. The experimental methodology involved closed system equilibration in sealed ampoules, quenching and electron probe X-ray microanalysis (EPMA) of compositions of phases. FactSage thermodynamic database obtained by combining earlier assessments of sub-systems was used to plan the targeted experiments, and the results of new experiments were used to improve the thermodynamic database. Important effects were revealed for the conditions of the present study: CaO decreases the concentration of Pb and S in slag; Al2O3 has small effect on Pb in slag, but significantly decreases the concentration of S in slag; ZnO has small effect on Pb in slag, but increases the concentration of S in slag. These experimentally measured effects were reproduced by the model.

Multicomponent phase space has been shown to consist of an enormous number of materials with different compositions, the vast majority of which have never been made or investigated, with great potential, therefore, for the discovery of exciting new materials with valuable properties. At the same time, however, the enormous size of multicomponent phase space makes it far from straightforward to identify suitable strategies for exploring the plethora of potential material compositions and difficult, therefore, to be successful in discovering desirable new materials. Unfortunately, all our knowhow and understanding has been developed for materials with relatively few components in relatively limited proportions, with most of our scientific theories relying essentially on linear assumptions of component dilution and independence that no longer apply in concentrated multicomponent materials. Trial and error, controlled substitution, parameterisation, thermodynamic modelling, atomistic modelling and machine learning techniques have all been employed as methods of exploring multicomponent phase space, with varying levels of success, but ultimately none of these techniques has proved capable of delivering consistent or guaranteed results. This paper provides an overview of the different techniques that have been used to explore multicomponent phase space, indicates their main advantages and disadvantages, and describes some of their successes and failures. [ABSTRACT FROM AUTHOR]

The Dom Feliciano Belt is the South American part of an extensive Neoproterozoic orogenic system that developed during the late Cryogenian–early Cambrian close to the margin of southwest Gondwana. The link of its evolution with the tectonic processes in its African counterpart is still not well understood. P–T estimates, Lu–Hf garnet–whole-rock ages, U–Pb monazite SIMS ages and REE garnet and monazite data from samples of the Porongos and Passo Feio complexes indicate diachronous tectonic evolution of the central Dom Feliciano Belt foreland. Metasedimentary rocks of the eastern Porongos Complex reached previously estimated metamorphic peak conditions of ~ 560–580 °C and 5.8–6.3 kbar at 654 ± 2 Ma, based on Lu–Hf isochron garnet–whole-rock age data. This episode represents an early orogenic thickening in the foreland as a response to the beginning of the transpressive convergent evolution of the belt. The monazite age of 614 ± 6 Ma (U–Pb SIMS) is interpreted as associated with post-exhumation magmatic activity in the foreland and suggests that the eastern Porongos Complex was exhumed sometime between ca. 660 and 615 Ma. The main metamorphic and deformation event in the Porongos Complex's western region occurred at ~ 545–565 °C and 4.3–5.3 kbar at 563 ± 1 Ma (garnet–whole-rock Lu–Hf isochron age). The exhumation of this part of the foreland is dated using monazite crystallising during garnet breakdown and suggests retrograde metamorphism at 541 ± 7 Ma (U–Pb SIMS). The main metamorphic fabric in the Passo Feio Complex further to the west developed at 571 ± 2 Ma (garnet–whole-rock Lu–Hf isochron age) at 560–580 °C and 4.7–6.4 kbar. The western part of the Porongos Complex and the Passo Feio Complex have deformed at similar P–T conditions and apparent geothermal gradients at ca. 570–565 Ma. These regions record a second crustal thickening event in the Dom Feliciano Belt foreland and the orogenic front migration towards the west as a response to the onset of crustal thickening on the African side of this long-lived transpressive orogenic system. [ABSTRACT FROM AUTHOR]

The blending of hydrogen and natural gas (H 2 -NG) has emerged as a crucial and cost-effective means for processing hydrogen fluids through natural gas networks thereby aiding transition to net-zero energy. Nonetheless, the effective adaptation of H 2 -NG mixtures, especially up to 20% hydrogen concentrations, to existing natural gas distribution and storage facilities relies heavily on a comprehensive understanding of their thermophysical properties. We measured densities of three binary mixtures of hydrogen and methane (xH 2 = 0.0532, 0.0858, and 0.2031) at temperatures between 278 and 398 K, and pressures up to 56 MPa using a vibrating tube densimeter (VTD). The VTD was calibrated using H 2 and H 2 O. The measured densities were in reasonable agreements with the predictions of two thermodynamic equations of states (EoSs), Multi-Fluid Helmholtz Energy Approximation (MFHEA) and Peng-Robinson (PR). The average absolute relative deviation (AARD) for the measured density against the predictions of the PR EoS are 1.07%, 1.09%, and 0.89% for xH 2 = 0.0532, 0.0858, and 0.2031 mol fractions respectively. While the AARD for the measured density against the predictions of MFHEA EoS are 0.16%, 0.16%, and 0.32% for xH 2 = 0.0532, 0.0858, and 0.2031 mol fractions respective. The MFHEA EoS, which has the structure of GERG-2008, has better agreements with our density data than the PR EoS. The relative high deviations with PR EoS results from the PR's simple structure making it deficient in calculating thermal properties of natural gas in saturated-liquid and homogeneous states. In addition, the uncertainty of the measured density was determined, and the experimental data were compared with available literature data. Finally, the compressibility factor (Z), speed of sound (w), specific heat capacity at constant volume (C V), and specific heat capacity at constant pressure (C p) were obtained from the experimental results and were compared with the predictions of MFHEA EoS. This work provides accurate density and other thermophysical data useful for engineering/process designs and modelling of H 2 and natural gas systems thereby enhancing energy transition strategy. [Display omitted] • Density measurements for H 2 + CH 4 (xH 2 = 0.0532, 0.0858, and 0.2031) binary mixtures between 278 and 397 K and up to 56 MPa using VTD. • The measured densities were compared with the predictions of MFHEA and PR EoSs. • Determination of compressibility factors and other derived properties such w , C V , and C P for the mixtures. [ABSTRACT FROM AUTHOR]

There is interest in exporting carbon-neutral liquid hydrogen (LH2) as a replacement for fossil fuels. However, transporting LH2 for maritime export is made difficult by the requirement for high performance insulation to reduce pressure rise and cargo losses through venting. One method to reduce boil-off losses is to allow the tank to self-pressurise along the journey and delay venting by increasing the tank maximum allowable working pressure (MAWP). To assess this, an analytical model was developed, in Matlab, to predict pressure rise and boil-off gas (BOG) generation. Perlite insulation was modelled using analytical expressions for temperature-dependent specific heat capacity and thermal conductivity. The model was tuned over a range of data, including for pressure and boil-off rate. This model was used to assess an LH2 carrier carrying four 40,000 m3 spherical tanks insulated with evacuated perlite. At atmospheric pressure, a loss rate of 0.04 % per day was predicted for the laden voyage. Over a voyage duration of 15 days the model predicts that boil-off can be reduced by 31 % when the tank is allowed to self-pressurise to 5 kPaG. This is primarily due to a reduced rate of boil-off as the liquid transitions from a subcooled to a saturated state. At higher pressures, the delay in venting was observed to be a major contributor to reduction in boil-off, with a reduction of 91 % in losses at MAWP of 60 kPaG. Pressure rise was observed to be significantly greater than a saturated liquid model would suggest, particularly at high fill levels. Finally, an empirical equation for the pressure rise was fitted to 27 data points from the literature, allowing for quick estimates of the pressure rise based on the fill level, the Rayleigh number and the surface to volume ratio in the ullage. This study suggests very low loss storage of LH2 can be achieved in large double-wall tanks over a sufficiently short journey, with only marginal pressurisation. Additional investigations on the effect of ship motion on phase change within the tank will be required to fully understand design considerations for LH2 storage tanks. • New analytical model of pressurised cryogenic storage for boil-off prediction. • Effect of venting pressure on boil-off is investigated for periods of up to 15 days. • Allowing pressurisation to 60kPaG reduced losses by 91% at high fill levels. • Empirical correlation developed for pressure rise. [ABSTRACT FROM AUTHOR]

Utilization of Portland cement to initiate the dissolution of blast furnace slag (BFS) in super-sulfated cement is limited by low slag substitution level and poor early strength. In this study, a new activator composed of anhydrite and calcium sulfoaluminate cement clinker was proposed to enhance the utilization of BFS in super-sulfated cement. Tests were conducted on the compressive strength, autogenous shrinkage, hydration heat, pH and conductivity of the composites. XRD, 29Si NMR, BSE and MIP were employed. Results reveal that ettringite, gypsum and C-S-H are the primary hydration products. The composites with 20% activator display the highest compressive strength and shrinkage accompanied by the highest hydration heat and degree, as well as the highest quantity of monomer silica tetrahedrons and the largest volume of fine pores. Thermodynamic modeling confirms the critical value for the activator-substitution level. Additionally, the activator-BFS composite exhibited significantly lower carbon emissions compared to Portland cement. [ABSTRACT FROM AUTHOR]

As a modern power grid that integrates advanced communication technology, sensor measurement technology, and intelligent control technology, the smart grid has good economy, reliability, and stability. Building a strong smart grid has important strategic significance for developing the national economy and improving Comprehensive National Power. The balance of electricity supply and demand, as a physical feature of the power system, determines the energy matching relationship between generation and consumption. Unreasonable power generation may lead to unmet electricity demand, as well as excess electricity and waste of resources. The energy storage has solved the problem of imbalance between supply and demand in most environments. The energy storage equipment provides a buffer space for electric energy, effectively adjusts the time unevenness of power grid load, realizes peak shaving and valley filling, and reduces the operation cost of the power grid. Taking the aboveground energy storage power station as the research object, the 3-D unsteady model of the small and medium-sized compressed energy storage system was established by using the FLUENT simulation software, and the correctness was verified through experimental methods. The influence of different environmental temperatures, chamber inflation flow rate, the thermodynamic characteristics of the surface condition and working chamber of the and energy storage were studied. The results show that the environmental temperature and expansion flow of oil storage chamber have important effects on its thermodynamic characteristics, while the surface conditions of oil storage chamber wall have little effect on its thermodynamic characteristics. [ABSTRACT FROM AUTHOR]

The phase equilibria of the ZnO-"FeO 1..5 ", ZnO-"FeO 1.5 "-SiO 2 , PbO–ZnO-"FeO 1.5 " and PbO–ZnO-"FeO 1.5 "-SiO 2 slag systems in equilibrium with air or metallic lead/iron were studied as part of the investigation of the 19-component PbO–ZnO–Cu 2 O–FeO–Fe 2 O 3 –CaO–SiO 2 –Al 2 O 3 –MgO–S-(As, Sn, Sb, Bi, Ag, Au, Ni, Cr, Co as minor elements) slag/matte/metal/speiss/gas system, supporting the operation/development of existing and emerging pyrometallurgical processes. In the experimental part of the study, samples underwent high temperature equilibration followed by quenching, and the direct measurement of the lead, zinc, iron and silicon concentrations in the liquid slag, solid oxide, and metal phases by electron probe microanalysis (EPMA). The a) massicot (PbO), b) spinel ((Zn, Fe)Fe 2 O 4), c) zincite ((Zn,Fe)O 1+x , 2 polymorphs), d) lead ferrite (Pb 2+x Fe 2 O 5+x), e) plumboferrite (Pb 4 Fe 22-x Zn x O 37), f) magnetoplumbite (Pb(Fe 2 O 3 ,PbFeO 2 ,PbZnO 2)Fe 10 O 16), and g) W-ferrite (PbZn 2-x Fe 16+x O 27) primary phase fields of the PbO–ZnO-"FeO 1.5 " system in equilibrium with air were studied between 780 and 1300 °C. The ZnO-"FeO 1.5 ", ZnO-"FeO 1.5 "-SiO 2 and PbO–ZnO-"FeO 1.5 "-SiO 2 systems in equilibrium with air were studied up to 1745 °C, significantly improving the availability of information on the composition range of the high- and low-Fe zincite ((Zn,Fe)O 1+x) phases, and on the liquid slag composition at the boundaries of their primary phase fields. Lastly, the solubilities of iron in larsenite (Pb(Zn,Fe)SiO 4) and melilite (Pb 2 (Zn,Fe)Si 2 O 7) in equilibrium with air or metal were studied between 700 and 800 °C. The newly obtained and existing experimental data were used to develop a self-consistent set of thermodynamic parameters describing all phases in the system using the FactSage computer package. [ABSTRACT FROM AUTHOR]

Abstract Most of the tectonic, metamorphic and geochronological data suggest that the Himalaya is essentially the consequence of a single orogenic cycle associated with the India-Asia collision during the Cenozoic era. Therefore, metamorphic assemblages and tectonic structures across the Himalayan range are systematically considered as post-collisional geological records. However, over the last decades, several observations arguing for geological events predating the continental collision have become increasingly recurrent in the literature. Nevertheless, although some of these arguments are thoroughly documented, they are unduly ignored in the construction of models drawing the tectono-metamorphic evolution of the Himalayan range. Yet, the occurrence of a pre-Himalayan history would have considerable consequences on the classical models for the building of the Himalaya. The recent discovery of inclusions of staurolite crystals in greenschist facies garnets from the Miyar Valley in Upper Lahul region (Himachal Pradesh; NW India) revives the debate on the existence of a pre-Himalayan metamorphism. Indeed, the occurrence of high-temperature staurolites included in greenschist facies garnets suggests that the High Himalayan Crystalline rocks experienced an amphibolite facies metamorphism prior the predominant Himalayan greenschist facies metamorphism observed in this part of the range. In this study, phase petrology, microtectonic investigations combined with preexisting geochronological data infer that the crystallization of the included staurolite predates the growth of Himalayan garnets. These original data bring new arguments to bear on the long lasting debate of the existence of a Pre-Himalayan orogenic cycle. They lead to the conclusion that the growth of staurolite predates the continental collision between India and Asia and reflects a metamorphic event that belongs to a pre-Himalaya orogenic cycle.

The chlorination of oxides of major concern in cassiterite concentrate with various chlorinating agents is investigated in light of their thermodynamic feasibilities to extract and recover their valuable metal components. Mechanisms responsible for the processes and their Gibbs free energy changes as a function of temperature to selectively separate and/or recover the metal(s) of interest and unwanted ones as their metallic chlorides are identified. Attention is given to gaseous (Cl2 and Cl2 + CO mixture) and solid (CaCl2 and MgCl2) chlorine sources, from which Cl2 + CO shows no reaction selectivity for any of the oxides but a feasible metal chloride formation for all. Chlorine gas (Cl2), on the other hand, could selectively form chlorides with metals of +2 oxidation state in their oxides, leaving those of high oxidation state unreacted. MgCl2, unlike CaCl2, is found capable of producing calcium, ferrous, and stannic chloride from their metallic oxides with enhanced reaction tendencies in the presence of silicon dioxide (SiO2). An overall study of the thermodynamic feasibility of all chlorine sources looked at alongside operational and environmental viabilities suitably suggests MgCl2 for a selective extraction of the valuable metal components in a cassiterite concentrate, in which case, moderate temperatures seem promising.

Ca2Fe2O5-based catalysts were synthesized from siderite and calcite precursors, which were processed in the form of pelletized samples and tested as water gas shift catalysts. Catalytic tests were performed in a tubular reactor, at temperatures in the range 400–500 °C and with different H2O:CO ratios, diluted with N2; this demonstrates the positive impact of Ca2Fe2O5 on conversion of CO and H2 yield, relative to corresponding tests without catalyst. The catalytic performance was also remarkably boosted in a microwave-heated reactor, relative to conventional electric heating. Post-mortem analysis of spent catalysts showed significant XRD reflections of spinel phases (Fe3O4 and CaFe2O4), and SiO2 from the siderite precursor. Traces of calcium carbonate were also identified, and FTIR analysis revealed relevant bands ascribed to calcium carbonate and adsorbed CO2. Thermodynamic modelling was performed to assess the redox tolerance of Ca2Fe2O5-based catalysts in conditions expected for gasification of biomass and thermochemical conditions at somewhat lower temperatures (≤500 °C), as a guideline for suitable conditions for water gas shift. This modelling, combined with the results of catalytic tests and post-mortem analysis of spent catalysts, indicated that the O2 and CO2 storage ability of Ca2Fe2O5 contributes to its catalytic activity, suggesting prospects to enhance the H2 content of producer gases by water gas shift. [ABSTRACT FROM AUTHOR]

Phase equilibria in the ZrO 2 -Ta 2 O 5 system were studied in the temperature range from 1673 K to 1973 K using equilibration technique and in the temperature range up to 2473 K using differential thermal analysis (DTA). Phase and chemical composition of the samples was characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-Ray analysis (EDX). Melting relations were studied using DTA followed by microstructure investigation by means of SEM/EDX. The eutectic reaction was determined at 1994 K and composition of 51 ± 2 mol% Ta 2 O 5. It was found that the intermediate compound Zr 6 Ta 2 O 17 melts by peritectic reaction at 2166 K. The heat capacity of this compound was measured using differential scanning calorimetry (DSC) in three temperature ranges from 100 K to 230 K, from 220 K to 570 K and from 330 K to 1295 K. Based on the obtained results and literature data thermodynamic parameters of the quasibinary ZrO 2 -Ta 2 O 5 system were optimized using the CALPHAD approach. [ABSTRACT FROM AUTHOR]

Autogenous self‐healing of cracks in water retaining concrete structures is included in Eurocode 1992‐3 as a possible measure to heal cracks up to a width of 200 μm without additional repair. Water flow through the crack leads to the closure of the fracture, mainly due to CaCO3 precipitation. However, despite standardization, the healing effect seems to be random in practice. This study uses thermodynamic modelling of cement hydration to examine how the timing of crack formation affects crack widening or closure due to chemical shrinkage or swelling and discusses the implications for autogenous self‐healing. It is found that the exact timing of early‐age crack formation can lead to crack widening or closure in the range of a few micrometres. This effect is most prominent for cracking within the first two days of curing and dependents on the cement type, the fraction of inert material in the mix design and the amount of shrinkage that translates into a macroscopic volume reduction. However, it is concluded that other more dominant factors must be at play leading to the discrepancy between laboratory results and the unpredictable healing efficiency observed in practice. [ABSTRACT FROM AUTHOR]

Most of the tectonic, metamorphic and geochronological data suggest that the Himalaya is essentially the consequence of a single orogenic cycle associated with the India-Asia collision during the Cenozoic era. Therefore, metamorphic assemblages and tectonic structures across the Himalayan range are systematically considered as post-collisional geological records. However, over the last decades, several observations arguing for geological events predating the continental collision have become increasingly recurrent in the literature. Nevertheless, although some of these arguments are thoroughly documented, they are unduly ignored in the construction of models drawing the tectono-metamorphic evolution of the Himalayan range. Yet, the occurrence of a pre-Himalayan history would have considerable consequences on the classical models for the building of the Himalaya. The recent discovery of inclusions of staurolite crystals in greenschist facies garnets from the Miyar Valley in Upper Lahul region (Himachal Pradesh; NW India) revives the debate on the existence of a pre-Himalayan metamorphism. Indeed, the occurrence of high-temperature staurolites included in greenschist facies garnets suggests that the High Himalayan Crystalline rocks experienced an amphibolite facies metamorphism prior the predominant Himalayan greenschist facies metamorphism observed in this part of the range. In this study, phase petrology, microtectonic investigations combined with preexisting geochronological data infer that the crystallization of the included staurolite predates the growth of Himalayan garnets. These original data bring new arguments to bear on the long lasting debate of the existence of a Pre-Himalayan orogenic cycle. They lead to the conclusion that the growth of staurolite predates the continental collision between India and Asia and reflects a metamorphic event that belongs to a pre-Himalaya orogenic cycle. [ABSTRACT FROM AUTHOR]

Investigation of polymineralic melt inclusions preserved in garnet of eclogite-facies metapelites of the Usagaran belt, Tanzania, is of particular importance as these metapelites, intercalated in oceanic metabasites, document the rare case of partial melting at high temperatures in a subducted oceanic crust. With an age of 2 Ga the rocks represent one of the oldest oceanic crusts and confirm a subduction process already at Paleoproterozoic times. Partial melting probably was initiated by dehydration melting under the presence of a CO2-rich fluid phase. The melt is preserved in siliceous polymineralic inclusions, while CO2 locally reacted with the garnet host to form dolomite-quartz-kyanite inclusions. During this reaction, the REE spectrum of garnet is adopted by the dolomite. Furthermore, graphite inclusions in garnet must have precipitated from the CO2 fluid by reduction. The highly ordered graphite structure indicates a formation temperature of at least 700 °C. Rehomogenization experiments of the siliceous polymineralic inclusions yield a homogeneous melt of rhyolitic, peraluminous composition. Thermodynamic modelling enables to deduce a P–T path in accordance with high P–T conditions (minimum 2.0 GPa, 900 °C) where a partial melt formed due to phengite breakdown leading to the preserved peak mineral assemblage garnet, alkali feldspar, kyanite, quartz and rutile. A very fast uplift of the oceanic crustal rocks can be deduced from the occurrence of very finely exsolved metastable ternary feldspar and from the preserved prograde zoning in garnet. [ABSTRACT FROM AUTHOR]

Mineral and fluid inclusions in mantle diamonds provide otherwise inaccessible information concerning the nature of mantle metasomatism and the role of fluids in the mass transfer of material through the Earth's interior. We explore the role of carbon concentration during fluid-rock metasomatism in generating the range of garnet and clinopyroxene compositions observed in diamonds from the sub-continental lithospheric mantle. We use the Deep Earth Water model to predict the results of metasomatism between silicic, carbonatitic and peridotitic fluids and common mantle rocks (peridotites, eclogites and pyroxenites) at 5 GPa, 1000 °C, across a range of redox conditions (log fO 2 = −2 to −4 ΔFMQ), and a wide range of initial carbon concentrations in the metasomatic fluids. Our results show that the predicted compositions of metasomatic garnets and clinopyroxenes are controlled by the initial geochemistry of fluids and rocks, with subsequent mineral-specific geochemical evolution following definable reaction pathways. Model carbon-rich metasomatic fluids that can form diamond (initial C-content >5.00 molal) result in Mg-rich garnets and clinopyroxenes typical of peridotitic, eclogitic, and websteritic inclusions in diamonds. However, model carbon-poor metasomatic fluids that do not form diamond result in Mg-poor, Ca-rich garnets and clinopyroxenes. Such garnets and clinopyroxenes do nevertheless occur as inclusions in diamonds. In our models, the abundance of carbon in the fluids controls the behaviour of the bivalent ions through the formation of aqueous Mg-Ca-Fe-C complexes, which directly govern the composition of garnets and clinopyroxenes precipitated during the metasomatic processes. As the C-rich initial fluids can form the higher Mg-eclogitic, peridotitic, and websteritic inclusions in diamonds, these inclusions can be syngenetic (metasomatic) or possibly protogenetic. However, in our models, the relatively Mg-poor, Ca- and Fe-rich eclogitic garnet and clinopyroxene inclusions found in mantle diamonds formed from C-poor fluids that do not precipitate diamond. These inclusions most likely reflect a metasomatic event prior to being incorporated into their host diamonds, or they could represent protolith-based protogenetic geochemistry. Therefore, the paragenetic groups used to classify diamonds should not be considered a genetic classification, as the role of fluid geochemistry appears to be more important than the one played by host rock geochemistry. [ABSTRACT FROM AUTHOR]

In this work, we investigated the drying process of a hardened gypsum plaster model (GP) that showed sodium sulfate efflorescence after subsequent exposure to water. Visible efflorescence could be prevented by adding small amounts of calcium formate (CF). Prism samples were prepared to investigate this observation, with an emphasis on chemical processes in the pore water. In the pure plaster, both sodium and sulfur accumulate at the surface of the prism, which leads to sodium sulfate precipitation. In the sample containing CF, calcium slightly accumulates at the surface, which leads to lower sulfur concentrations, because the porewater is in equilibrium with gypsum. Thermodynamic calculations show that higher sodium concentrations are then necessary to reach sodium sulfate supersaturation than without CF. These concentrations are not exceeded during early stages of the drying process, which ultimately leads to the sodium sulfate precipitation inside the prism. Therefore, sodium sulfate efflorescence can be hindered on gypsum plaster by the addition of CF. [ABSTRACT FROM AUTHOR]

The work developed presents, for the first time, a tool to analyze all the thermodynamic models used in the study and development of Stirling engines: isothermal, ideal adiabatic and adiabatic with losses, combined adiabatic thermodynamic with finite speed (CAFS), thermodynamic with finite speed (FST), ideal polytropic and polytropic with losses (PSVL), allowing a comparative study of them.This software (ASCE-UMA), designed and implemented in a Matlab GUI® allows to obtain the operating parameters of these engines, calculating the thermodynamic parameters, power output and efficiency. Additionally, the thermodynamic models can be evaluated with different mechanical configurations, for which different drive mechanisms are implemented: Sinusoidal, Alfa Ross yoke types, Alfa Ross V yoke, Beta rhombic type and free piston Stirling engine (FPSE). Thermoacoustic and other, models could be analyzed by virtue of their similarity of movement with some of the implemented models. In the same way, ASCE-UMA allows the study of various exchanger configurations, as well as various regenerator models. The versatility of ASCE-UMA allows the development analysis of all the fundamental elements of a new prototype as well as the analysis of experimental data by performing a customized and detailed calculation. To test the effectiveness of ASCE-UMA, its performance is verified by analyzing Ross Yoke D-90 models and a GM GPU-3 engine.This is a tool that allows to analyze and comparing the different models and the different existing mechanisms for the multiple configurations of Stirling engines in an easy and intuitive application with a high-quality graphical interface.

The phase equilibria of the PbO–ZnO-"CuO 0.5 "- SiO 2 system were studied as part of the investigation of the 19-component PbO–ZnO–Cu 2 O–FeO–Fe 2 O 3 –CaO–SiO 2 –Al 2 O 3 –MgO–S-(As, Sn, Sb, Bi, Ag, Au, Ni, Cr, Co as minor elements) slag/matte/metal/speiss/gas system in support of the development and optimization of pyrometallurgical processes. In the experimental study, samples were equilibrated at high temperatures, then quenched, and the lead, zinc, copper and silicon concentration in the phases were directly measured by electron probe X-ray microanalysis (EPMA). The cristobalite (SiO 2) primary phase field of the PbO–SiO 2 system was experimentally studied between 1575 and 1717 °C. The massicot (PbO), zincite ((Zn,Cu)O), cuprite (Cu 2 O), copper plumbite (Cu 2 PbO 2) and Pb 2 SiO 4 primary phase fields of the PbO-"CuO 0.5 "-SiO 2 , PbO–ZnO-"CuO 0.5 " and PbO–ZnO–SiO 2 systems were studied between 664 and 1100 °C. The cuprite (Cu 2 O), willemite ((Zn,Cu) 2 SiO 4), larsenite (PbZnSiO 4) and melilite (Pb 2 ZnSi 2 O 4) secondary phase fields of the PbO–ZnO-"CuO 0.5 "-SiO 2 system in equilibrium with metal and tridymite/quartz (SiO 2) or zincite ((Zn,Cu)O) were studied between 745 and 1100 °C. The zincite ((Zn,Cu)O), tenorite ((Cu,Zn)O) and willemite ((Zn,Cu) 2 SiO 4) solid solutions in equilibrium with air or pure O 2 at 1 atm were studied between 900 and 1100 °C. Using the FactSage thermodynamic calculation software, a self-consistent set of parameters based on the Modified Quasichemical Model (MQM) were developed to describe the newly obtained and existing experimental data. [ABSTRACT FROM AUTHOR]

The advancements in digital twins when combined with the use of the machine learning tools can facilitate the effective health assessment and diagnostics of safety critical systems. This study aims at developing a framework to address the health assessment of marine engines utilising digital twins based on first-principles. This framework follows four distinct stages, with the former two including the marine engine digital-twin set up by customising the required thermodynamic models, as well as its calibration using tests trials data representing the engine healthy conditions. In the third stage, measurements from actual operating conditions are corrected and subsequently employed to develop the digital twin representing the prevailing conditions. The fourth stage deals with the engine health assessment by assessing health metrics derived from the developed digital twins. This framework is demonstrated in a case study of a large marine four-stroke nine-cylinder propulsion engine. The results demonstrate that three cylinders are identified to be underperforming leading to an average increase of the engine Brake Specific Fuel Consumption (BSFC) by 2.1%, whereas an average decreases of 6.8% in Indicated Mean Effective Pressure (IMEP) and 6.1% in the Exhaust Gas Temperature (EGT) are exhibited for the underperforming cylinders across the entire operating envelope. The developed digital twins facilitate the effective mapping of the engine performance for the entire operating envelope under several health conditions, providing enhanced insights for the current engine health status. The advantages of the proposed framework include the use of easily obtained data, and its application to several engine types including two and four-stroke engines for both propulsion and auxiliary use. [ABSTRACT FROM AUTHOR]

The parallel tangent method widely applied to predict the composition and driving force to form a nucleus from an oversaturated solution is extended in this paper. The parallel tangent method is shown to (i) Over-estimates the composition difference between the first nucleus and the parent phase, (ii) Neglects the composition dependence of interfacial energies and (iii) Neglects the composition dependence of probability to form embryos prior to nucleation. New model equations are developed here for the composition dependence of the interfacial energies and probability to form the embryos as function of nucleus composition at given matrix composition. The most probable composition of the first nucleus is found at the maximum of the driving force of nucleation extended by the new model equations. The success of the extended method is demonstrated for an Al-Fe liquid alloy with 0.3 w% of Fe to predict the first nucleating intermetallic phases upon cooling after nucleation of the fcc phase. It is shown that although the prediction based on the parallel tangent method contradicts experimental observations, the prediction based on our extended method agrees with them. [ABSTRACT FROM AUTHOR]

Quartzite stone powder (QP) is a mining and constructional byproduct that causes severe environmental problems. In this study, to realize its resourceful utilization, cement was partially substituted with four types of QP characterized with different fineness in preparation of an environment-friendly cementitious material. Mechanical properties, hydration heat releasing, hydration products, and porosity of blended materials were presented. The mechanism of the hydration process and microstructure evolution was discussed. The results show that the fineness of QP has a strong impact on the strength development as well as the hydration reaction. The addition of fine QP (600 and 800 m2 kg−1) accelerates the hydration of cement by providing more nucleation sites for hydration products, and refines the pore structure via filling effect. Moreover, the incorporation of QP in binders could reduce cement usage and bring sustainability and economic benefits in reducing the energy consumption, carbon emission and cost of cementitious materials. [ABSTRACT FROM AUTHOR]

Antigorite dehydration is a process able to release, in comparison with other minerals, the highest amount of H2O from a subducting slab. The released fluid delivers critical elements (e.g., S, Cu, and REE) to the overlying subarc mantle, modifying the mantle source of arc magmas and related ore deposits. Whether antigorite breakdown produces oxidising or reducing fluids is debated. Whereas previous studies have investigated antigorite dehydration in serpentinites (i.e., in a (C)AMFS-H2O system), this contribution is devoted to the CMFS-COHS carbonate system, which is representative of the metacarbonate sediments (or carbonate-dominated ophicarbonate rocks) that sit atop the slab. Thermodynamic modelling is used to investigate the redox effect of the carbonate-buffered antigorite dehydration reactions (i.e., brucite breakdown and antigorite breakdown) on electrolytic fluid geochemistry as a function of P-T-fO2. The influence of P-T-fO2 conditions on the solubility of C and S, solute-bound H2 and O2, fluid pH, the average valence states of dissolved C and S, and the fluid redox budget indicates that, in metacarbonate sediments, the CaCO3+antigorite reaction tends to produce reducing fluids. However, the redox state of such fluids is buffered not only by the redox state of the system but also, most importantly, by concomitantly dissolving redox-sensitive minerals (i.e., carbonates, graphite, pyrite, and anhydrite). A qualitative correlation between the redox state of the system and the possible depth of fluid release into the mantle wedge is also derived. [ABSTRACT FROM AUTHOR]

Sorption of pure CO2 and CH4 and CO2/CH4 binary gas mixtures in amorphous glassy Poly(2,6-dimethyl-1,4-phenylene) oxide (PPO) at 35 °C up to 1000 Torr was investigated. Sorption experiments were carried out using an approach that combines barometry with FTIR spectroscopy in the transmission mode to quantify the sorption of pure and mixed gases in polymers. The pressure range was chosen to prevent any variation of the glassy polymer density. The solubility within the polymer of the CO2 present in the gaseous binary mixtures was practically coincident with the solubility of pure gaseous CO2, up to a total pressure of the gaseous mixtures equal to 1000 Torr and for CO2 mole fractions of ~0.5 mol mol−1 and ~0.3 mol mol−1. The Non-Equilibrium Thermodynamics for Glassy Polymers (NET-GP) modelling approach has been applied to the Non-Random Hydrogen Bonding (NRHB) lattice fluid model to fit the solubility data of pure gases. We have assumed here that no specific interactions were occurring between the matrix and the absorbed gas. The same thermodynamic approach has been then used to predict the solubility of CO2/CH4 mixed gases in PPO, resulting in a deviation lower than 9.5% from the experimental results for CO2 solubility. [ABSTRACT FROM AUTHOR]

Steel is used as reinforcement in construction materials and it is also an important component of cement-stabilized waste materials to be disposed of in deep geological repositories for radioactive waste. Steel corrosion releases dissolved Fe(II/III) species that can form corrosion products on the steel surface or interact with cementitious materials at the iron-cement interface. The thermodynamically stable Fe species in the given conditions may diffuse further into the adjacent, porous cement matrix and react with individual cement phases. Thus, the retention of Fe(II/III) by the hydrate assemblage of cement paste is an important process affecting the diffusive transport of the aqueous species into the cementitious materials. The diffusion of aqueous Fe(II/III) species from the steel surface into the adjacent cementitious material coupled with the kinetically controlled formation of iron corrosion products, such as by Fe(II) oxidation, decisively determines the extension of the corrosion front. This review summarises the state-of-the art knowledge on the interaction of ferrous and ferric iron with cement phases based on a literature survey and provides new insights and proper perspectives for future study on interaction systems of iron and cement. [ABSTRACT FROM AUTHOR]

Cooling processes like refrigeration and air conditioning are known for their high energy consumption. Since most Indian states experience abundant sunshine year-round, solar refrigeration is a suitable technology for the country. Solar-powered absorption refrigeration systems offer a viable alternative to traditional refrigeration, providing not only cooling and ice-making capabilities but also energy savings and environmental benefits. However, further research is necessary to enable widespread industrial adoption and the replacement of conventional refrigeration systems with solar powered absorption system. Using solar energy for an air-conditioning system is typically more cost-effective, when it can fulfil both heating and cooling needs. This research focuses on the thermodynamic modelling of a system, specifically the effect of various temperature on COP. Thermodynamic modelling was done with the help of first law of thermodynamics. Using engineering equation solver software, study simulated the cycle and equations were developed for energy and mass flow for each component. Further, before proceeding to analysis some assumptions were also made. We then analysed how the Coefficient of Performance (COP) changed when varying the temperatures across each component. Our findings show that COP increases with increase in condenser, evaporator, and absorber temperatures, but it is declined with decrease in generator temperature.

Ca2Fe2O5-based catalysts were synthesized from siderite and calcite precursors, which were processed in the form of pelletized samples and tested as water gas shift catalysts. Catalytic tests were performed in a tubular reactor, at temperatures in the range 400–500 °C and with different H2O:CO ratios, diluted with N2; this demonstrates the positive impact of Ca2Fe2O5 on conversion of CO and H2 yield, relative to corresponding tests without catalyst. The catalytic performance was also remarkably boosted in a microwave-heated reactor, relative to conventional electric heating. Post-mortem analysis of spent catalysts showed significant XRD reflections of spinel phases (Fe3O4 and CaFe2O4), and SiO2 from the siderite precursor. Traces of calcium carbonate were also identified, and FTIR analysis revealed relevant bands ascribed to calcium carbonate and adsorbed CO2. Thermodynamic modelling was performed to assess the redox tolerance of Ca2Fe2O5-based catalysts in conditions expected for gasification of biomass and thermochemical conditions at somewhat lower temperatures (≤500 °C), as a guideline for suitable conditions for water gas shift. This modelling, combined with the results of catalytic tests and post-mortem analysis of spent catalysts, indicated that the O2 and CO2 storage ability of Ca2Fe2O5 contributes to its catalytic activity, suggesting prospects to enhance the H2 content of producer gases by water gas shift.

Ceramic tile manufacturing is a highly energy-intensive process. Concerns about carbon emissions and energy costs make energy management crucial for this sector, which holds a leading role in Italian industry. The paper discusses the energetic and environmental performance of cogeneration (CHP) in the ceramic industry, where prime mover exhaust heat is supplied to a spray-dryer system, contributing to the satisfaction of the thermal demand and decreasing natural gas consumption. A thermodynamic model of a dryer unit, validated against real data, has been set-up to provide a detailed representation of the thermal fluxes involved in the process. Then, the thermal integration with two types of CHP prime movers of similar electric size (4 MW) is investigated. Energetic results show that the gas turbine can contribute up to 81% of dryer thermal consumption, whilst internal combustion engine contribution is limited to 26%. A methodology was ad-hoc defined for the environmental assessment of CHP, accounting for global (CO2) and local (CO and NOX) emissions. Results confirm that CHP units guarantee reduction of CO2 and NOX compared to separate generation, with maximum values equal to 81 g/kWhth and 173 mg/kWhth, respectively; CO emission is decreased only in the case of gas turbine operation, with savings equal to 185 mg/kWhth. [ABSTRACT FROM AUTHOR]

Partial melting has been shown to be an important mechanism for intracrustal differentiation and granite petrogenesis. However, a series of compositional differences between granitic melt from experiments and natural granites indicate that the processes of crustal differentiation are complex. To shed light on factors that control the processes of crustal differentiation, and then the compositions of granitic magma, a combined study of petrology and geochemistry was carried out for granites (in the forms of granitic veins and parautochthonous granite) from a granulite terrane in the Tongbai orogen, China. These granites are characterized by high SiO2 (>72 wt%) and low FeO and MgO (<4 wt%) with low Na2O/K2O ratios (<0.7). Minerals in these granites show variable microstructures and compositions. Phase equilibrium modelling using P–T pseudosections shows that neither anatectic melts nor fractionated melts match the compositions of the target granites, challenging the conventional paradigm that granites are the crystallized product of pure granitic melts. Based on the microstructural features of minerals in the granites, and a comparison of their compositions with crystallized minerals from anatectic melts and minerals in granulites, the minerals in these granitoids are considered to have three origins. The first is entrained garnets, which show comparable compositions with those in host granulites. The second is early crystallized mineral from melts, which include large plagioclase and K‐feldspar (with high Ca contents) crystals as well as a part of biotite whose compositions can be reproduced by crystallization of the anatectic melts. The compositions of other minerals such as small grained plagioclase, K‐feldspar and anorthoclase in the granites with low Ca contents are not well reconstructed, so they are considered as the third origin of crystallized products of fractionated melts. The results of mass balance calculation show that the compositions of these granites can be produced by mixing between different proportions of crystallized minerals and fractionated melts with variable amounts of entrained minerals. However, the calculated modal proportions of different crystallized minerals (plagioclase, K‐feldspar, biotite and quartz) in the granites are significantly different from those predicted by melt crystallization modelling. Specifically, some rocks have lower modes of biotite and plagioclase, whereas others show lower K‐feldspar modes than those produced by melt crystallization. This indicates that the crystallized minerals would be differentially separated from the primary magmas to form the evolved magmas that produce these granites. Therefore, the crystal entrainment and differential melt‐crystal separation make important contributions to the composition of the target granites. Compared with leucogranites worldwide, the target granites show comparable compositions. As such, the leucogranites may form through the crystal fractionation of primary granitic magmas at different extents in addition to variable degrees of partial melting. [ABSTRACT FROM AUTHOR]

Phase equilibria in Ag–In–Pd ternary system were studied using Scanning electron microscopy, Energy-dispersive X-ray spectroscopy (EDX) and X-Ray diffraction method (XRD). The solubilities of the third components in Ag–In and In–Pd binary phases were established, as well as composition ranges (from 4 to 17.5 at % Ag at 25 at % In) and crystal structure of τ ternary compound (Al3Ti). New thermodynamic assessment of Ag–In–Pd ternary system was performed, basing on the published experimental data and those obtained in the present work. Good agreement was achieved between the calculation results and the experimental data on phase equilibria and thermodynamic properties of the phases. The results of the calculation reproduce well experimental DTA/DSC data of three samples (the data were not included into the optimization). This additionally supports the correctness of the obtained thermodynamic description. [ABSTRACT FROM AUTHOR]

This paper reports on a review on combined heat and power (CHP). A historical examination points out that combined heat and power was primarily used for hot heat valorizing (CHHP). The technological aspects evolved with this configuration first in industrial size. More recently, configuration with cold heat and power production (CCHP) appeared. Then, the immediate extension of this configuration led to trigeneration configuration, providing three useful effects: power and hot and cold heat. We suggest in the paper that progress regarding this last approach remains to be achieved towards the extension of trigeneration to polygeneration, whatever the form of energy and substance (water uses, for example). More generally, we consider that the goal, regarding the energy uses, is the integration of all needs in the design stage of the whole system (design optimization). Then, the evolution of the system in time should be considered, this being the purpose of control command of the optimized concern. This part remains to be developed in the future. Currently, the optimized design is well-started from the thermodynamic point of view with good criterion (efficiency), completed with economic and environmental objectives or constraints, as is reported in the review. [ABSTRACT FROM AUTHOR]

Metals that are exposed to high pressure hydrogen gas may undergo detrimental failure by embrittlement. Understanding the mechanisms and driving forces of hydrogen absorption on the surface of metals is crucial for avoiding hydrogen embrittlement. In this study, the effect of stress-enhanced gaseous hydrogen uptake in bulk metals is investigated in detail. For that purpose, a generalized form of Sievert's law is derived from thermodynamic potentials considering the effect of microstructural trapping sites and multiaxial stresses. This new equation is parametrized and verified using experimental data for carbon steels, which were charged under gaseous hydrogen atmosphere at pressures up to 1000 bar. The role of microstructural trapping sites on the parameter identification is critically discussed. Finally, the parametrized equation is applied to calculate the stress-enhanced hydrogen solubility of thin-walled pipelines and thick-walled pressure vessels during service. [Display omitted] • Improvement of Sievert's law to consider trapping sites and stress states. • Calculation and validation of gaseous hydrogen solubility under extreme conditions. • Hydrogen uptake measured for L450 steel at 200 and 1000 bar. • Calculation of the hydrogen solubility in pipes and pressure vessels. • Comprehensive literature survey of gaseous hydrogen solubility. [ABSTRACT FROM AUTHOR]

The brownmillerite phase Ca 2 Fe 2 O 5 was processed by the reactive firing of calcite and a natural siderite for prospective catalytic applications. Thermogravimetry and X-ray diffraction (XRD) was used to monitor the decomposition of precursors and its dependence on heating rate and atmosphere. Taguchi planning was used to assess the impact of firing temperature, time, and rate of heating on the conversion of precursors reflected by I 121 s p : I 121 b peak intensity ratio of main XRD reflections of secondary spinel phase CaFe 2 O 4 and brownmillerite. The onset of additional minor phases (Ca 2 Al 2 SiO 7 and Ca 2 SiO 4) was ascribed to the reaction of a fraction of calcia with gangue components of the siderite precursor. Thermodynamic modelling was used as a guideline for synthesis in non-oxidising conditions to hinder the onset of CaFe 2 O 4. These guidelines allowed one to obtain high conversion to Ca 2 Fe 2 O 5 with enhanced crystallinity at 700 °C, in an inert Ar atmosphere. Faster reactivity at T ≥ 800 °C in this oxygen-lean atmosphere, leads to highly crystalline Ca 2 Fe 2 O 5 coexisting with the onset of wustite and/or metallic Fe, which account for the oxygen balance, and calcium silicates, by reaction of calcia with silica. [ABSTRACT FROM AUTHOR]

The substitution of Portland cement clinker with a combination of calcium carbonate and calcined clay is a promising binder concept to lower the CO 2 footprint of the cement industry due to the synergetic effect of both materials which form carbo-aluminate hydrates. In this study, the reactivity of several calcined clays was tested using the R3 test and mortar strength testing in different combinations with calcium carbonate and Portland cement. A multiple regression analysis revealed that the reactivity in the R3 test depends mainly on the amorphous Al 2 O 3 and to a minor extent on the grain size and the MgO content. It was found that the most reactive calcined clay according to the R3 test led to no significant increase in compressive strength between 7 and 28 days. This clay also shows a slightly lower overall strength after 28 days than a calcined clay that was rated "medium reactive" according to the R3 test. The most reactive calcined clay was further investigated in a hydration study using X-ray diffraction. Based on this, a thermodynamic model was built and revealed that only a comparatively small percentage of the calcined clay reacted after 28 days. • Amorphous Al2O3 as most important factor for calcined clay reactivity using R3 test. • Low strength gain after 7 days using a highly reactive calcined clay. • Combining XRD with thermodynamic modeling. • Low reaction degree after 28 days of the highly reactive calcined clay. • Lower reactive calcined clays can outperform higher reactive ones. [ABSTRACT FROM AUTHOR]

[Display omitted] The pharmaceutical industry is increasingly drawn to the research of innovative drug delivery systems through the use of supercritical CO 2 (scCO 2)-based techniques. Measuring the solubility of drugs in scCO 2 at varying conditions is a crucial parameter in this context. In this research, the supercritical solubility of two pharmaceutical ingredients, namely Febuxostat and Chlorpromazine, has been assessed theoretically using various thermodynamic approaches, including PR, SRK, UNIQUAC, and Wilson models. Additionally, hybrid machine learning models of PO-GPR, and PO-KNN were applied to anticipate the supercritical solubility of these medicines. Verification of the accuracy of each model for each pharmaceutical substance is conducted against previously reported experimental solubility data. In the comparison between the SRK and PR models, it is observed that the SRK model displays greater precision in correlating the solubility of both drugs. It consistently achieves a mean R adj value of 0.995 across all cases and mean AARD% values of 14.47 and 9.30 for Febuxostat and Chlorpromazine, respectively. Furthermore, the findings indicate that the UNIQUAC model surpasses the Wilson model in precisely representing the solubility of both medicines. It consistently achieves a mean R adj value higher than 0.985 across both cases and mean AARD% values of 11.39 and 7.08 for Febuxostat and Chlorpromazine, respectively. Additionally, the performance of both hybrid machine learning models proved to be excellent in anticipating the supercritical solubility of both compounds. [ABSTRACT FROM AUTHOR]

A combined experimental and modelling study into the Pb-Mo-O system has been conducted in view of the safety analysis for lead-cooled nuclear systems. The thermal expansion and low-temperature heat capacity of the ternary compounds PbMoO 4 and Pb 2 MoO 5 have been determined experimentally, as well as the melting enthalpy of PbMoO 4. Moreover, XANES measurements have confirmed the hexavalent oxidation state of Mo in PbMoO 4 and Pb 2 MoO 5. A thermodynamic model of the ternary system including the ternary phases PbMoO 4 , Pb 2 MoO 5 and Pb 5 MoO 8 has also been developed in this work based on the CALPHAD methodology. For the first time, an ionic two-sublattice model is used for the liquid phase, while the compound energy formalism is used for the solid phases. [Display omitted] • A thermodynamic model of the Pb-Mo-O system is described. • The low-temperature heat capacity and thermal expansion of Pb 2 MoO 5 and PbMoO 4 have been measured. • The melting enthalpy of PbMoO 4 has been determined. • XANES of Pb 2 MoO 5 and PbMoO 4 at the Mo K-edge are reported. [ABSTRACT FROM AUTHOR]

Calcium sulfoaluminate-ferrite (CSA-F) clinkers were prepared using the alumina production waste bauxite residue (BR) as one of the raw materials, next to limestone, kaolin, and gypsum. A complementary approach was employed, aiming to maximize the desired ye'elimite phase. This consisted of thermodynamic modelling and computational statistics via response surface modelling, which enabled the identification of the best raw meal by varying the proportions of the chosen raw materials and the optimal clinkering conditions by unraveling the interaction between clinkering temperature and time. The optimal parameters were for a raw meal consisting of 38 wt% BR, 42 wt% limestone, 5 wt% kaolin, and 15 wt% of gypsum, fired for 60 min at 1300 °C. The accuracy of the model was assessed experimentally on a clinker synthesized at a temperature range of 1250–1300 °C for 30 and 60 minutes, followed by rapid cooling. Based on the characterization results, firing at 1300 °C for 60 minutes was the optimal set of conditions to maximize ye'elimite formation, which was in accordance with the response surface model. In addition, clinker 1300_60 exhibited the highest 28d compressive strength of 33 MPa due to the presence of Ternesite phase. In conclusion, the combined methodology endorsed and presented herein is a pragmatic and relatively accurate methodology for producing low-CO 2 clinkers from bauxite residue and can likely be transferred to other unexploited secondary raw materials. • Clinker production was optimized using thermochemical modelling and SRM. • An optimum mix proportion contains 38 wt% BR, 42 wt% LS, 15 wt% G, and 5 wt% K. • 1300_60 shown to be optimal for maximizing the ye'elimite formation based on SRM. • 1300_60 reported the highest ye'elimite content with a cubic lattice structure. • 1300_60 reported the highest late-age compressive strength. [ABSTRACT FROM AUTHOR]