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Introduction: The main goal of this study was to describe the Czech population of patients with MG in terms of demographics, disease characteristics, management approaches, and treatment trends. Methods: We selected all patients, both incident and prevalent, who were enrolled in the Czech MyReg registry between August 24, 2015 and November 19, 2021. For the descriptive analysis, all patients enrolled in the registry, regardless of their date of diagnosis or date of enrolment, were included. We analyzed the following disease-related endpoints: myasthenia gravis composite (MGC) score, forced vital capacity (FVC), and Myasthenia Gravis Foundation of America (MGFA) clinical classification. Results: The incidence showed a consistent increasing trend from 0.62 to 3.13. The mean MGC score was 5.0 (median 4.0, 95% CI 4.7, 5.3) representing mild form of MG. The difference in FVC from the predicted value in patients during and without myasthenic crisis was 58.93% (95% CI 37.27, 80.59) and 75.93% (95% CI 74.87, 77.00), respectively. We identified 70 patients (5.0%) with refractory MG, of whom 58.6% were female. The MGFA classifications in those with refractory vs. non-refractory disease was as follows: IIa 21.8% vs 23.2%, IIb 45.3% vs 33.6%, and IIIb 14.1% vs 4.6%, respectively. Conclusion: Our analysis shows that the incidence of MG is increasing in the Czech Republic and that patients with refractory disease, of whom up to 58% are female, have a higher burden of disease than non-refractory patients. [ABSTRACT FROM AUTHOR]

Background: Refractory esophageal stricture is the common complication of extensive endoscopic submucosal dissection (ESD), without satisfactory endoscopic treatment strategies. We evaluated the efficacy, safety, and long-term patency of the modified endoscopic radial incision and selective cutting combined with short-term stenting (RISC-STS) for the treatment of refractory esophageal stenosis. Methods: This was a retrospective study. Patients diagnosed with refractory esophageal stricture from June 2016 to June 2023 were enrolled. Efficacy, safety, and risk factors for dysphagia after RISC-STS operation were assessed. Results: Compared with clinical symptoms before RISC-STS, there was no significant improvement in the times of stricture recurred (p = 0.75). However, the narrowest diameter of esophageal stenosis was significantly larger after RISC-STS treatment (p = 0.04). Corresponding dysphagia scores after RISC-STS were obviously lowered according to the Mellow–Pinkas grading scale (p = 0.002). More cases ((14 (60.87%) vs 5 (21.74%)) received valid symptom-relief periods after RISC-STS (p = 0.0004). The complications of RISC-STS include perforation (4.35%), fever (4.35%), and pain (30.43%). Univariate Cox analysis suggested that resection length >7 cm of scar tissue was a risk factor for refractory dysphagia after RISC-STS. Conclusion: The present study revealed that RISC-STS is an effective and safe technique for refractory esophageal stricture with lower restenosis, higher valid symptom-relief rate, and fewer complications. [ABSTRACT FROM AUTHOR]

Background: Juvenile Idiopathic arthritis (JIA) is one of the most common chronic diseases in children. It still remains a challenge to treat refractory poly-articular course JIA patients, especially in Bangladesh, where patients from low socio-economic backgrounds are unable to manage biological agents. Tofacitinib is one of the alternative options to biological agents, which can be taken orally and is cost effective. The purpose of this prospective observational study was to evaluate the efficacy of tofacitinib in the treatment of refractory poly-articular course JIA cases. Materials and methods: This study was carried out in the Department of Pediatrics, Bangabandhu Sheikh Mujib Medical University (BSMMU). A total number of 50 refractory polyarticular course JIA patients received JAK-2 inhibitor, tofacitinib along with other drugs according to the recommended doses. The disease activity level was measured by Juvenile Arthritis Disease Activity Score-27 (JADAS-27). All the cases were assessed at baseline, 6th, 12th and52nd week of tofacitinib therapy. The relevant statistical tests were applied for data analysis. Results: After treating the refractory cases with tofacitinib, arthritis subsided, and laboratory parameters improved in all the cases. Overall JADAS-27 score improvement was 40.67%, 56.38% and 96% at 6th, 12th and 52nd week of follow-up respectively. It was also possible to taper the dose of steroid gradually and stopped it by 24 weeks. Tofacitinib was well tolerated with minimum side effects. Conclusions: Tofacitinib was effective to all the children with poly-articular course JIA. It was well tolerated and had very few tolerable adverse effects. [ABSTRACT FROM AUTHOR]

The solid carbon produced by the CO disproportionation reaction can cause severe damage to refractories, especially in the presence of H 2. To provide a theoretical basis for the design of refractories for low-carbon metallurgical equipment. Carbon deposition experiments of clay refractories, mullite refractories, and corundum-mullite refractories were researched at 550 °C under CO-H 2 atmosphere. The results show that carbon deposition occurs mainly in the vicinity of agglomerated iron. A small amount of agglomerated iron is sufficient to catalyze the production of large amounts of filamentous carbon and to damage refractories. In addition, the iron content and form have a significant influence on the refractory under CO-H 2 atmosphere. For mullite samples with less than 1 wt% iron, carbon deposition occurs mainly in the iron agglomerate regions and the damage rate of the samples is relatively low. For clay samples with 2.5 wt% iron, there are very large amounts of iron agglomerates in the aggregate and the matrix, and as a result most of the samples are damaged. Finally, the mechanism of refractory failure by carbon deposition under CO-H 2 atmosphere was revealed. The CO diffuses into the pores of the refractory, and the filamentous carbon produced by the CO disproportionation reaction grows near the agglomerated iron. As the pores fill with filamentous carbon, the carbon begins to densify and exerts an outward force on the refractory. When this force exceeds the bonding strength of the refractory, it will be damaged. [ABSTRACT FROM AUTHOR]

The copper industry continuously uses great amounts of Cr-containing refractories, which are installed in all heating devices, despite their known negative environmental impact. The development of alternative materials seems feasible via replacing chromite spinel with other Cr-free spinel, using magnesia or alumina as a dominant component in the composition of new refractories. In light of the longstanding issue, the article presents the properties of key refractory raw materials (magnesia and alumina) and potential Cr-free spinels which can be combined to emerge a new generation of refractories dedicated to the copper industry. Subsequently, the results of FactSage corrosion simulations were revealed for Cr-refractories and seven Cr-free magnesia-based refractories containing spinels of different chemistry against industrial copper converter slag with Fe/SiO 2 of 2.5. Through tracking the changes in solid and liquid phases appearing during interactions in a temperature range of 1100–1400 °C as well as liquid viscosity alterations, the most prospective solutions were identified with reference to the properties of commercial MgO-Cr₂O₃ refractories. [ABSTRACT FROM AUTHOR]

Refractory liner bricks in the hot zone of rotary lime kilns can sustain wear and corrosion during contact with fuel ashes and quicklime (QL), a product composed mainly of CaO. The effects on a MgO-based refractory after exposure at 1400 °C for 96 h to olive pomace ash (OPA) and coal ash (CA), with and without QL, were investigated. Exposure of the refractory to only OPA caused slag intrusion with no ash deposits remaining on top, while CaMgSiO 4 (monticellite) was also identified as a new phase. When exposed to only CA, the refractory exhibited dissolution into the molten slag and 0.5–2 mm cracks were found on the surface interfacing the ash. Mg 2 SiO 4 (forsterite) and CaMgSiO 4 were identified as new formed phases. Exposure of the refractory to OPA + QL and CA + QL caused less slag intrusion and substantial amounts of ash/QL deposit remained afterwards. No new phases were identified. The differences in interactions between the exposure materials and refractory were supported by thermochemical equilibrium analysis. Apparent Ca-Si–rich or Ca-rich melts were found in all the exposed samples, but potassium (K) was found to be depleted in all samples, including those involving OPA, which was rich in K. Furthermore, with the exception of exposure to only CA, the other exposures caused the cold crushing strength (CCS) of the refractory to increase compared to its original value. This was attributed to the sintering of the refractory microstructure. The CCS of the refractory decreased after exposure to only CA. The findings of this study enhance understanding of how CA and OPA impact MgO refractories in lime kilns, supporting initiatives aiming at reducing fossil fuel use. The results are encouraging and motivate further investigation. • MgO-based refractories were exposed to different fuel ashes with/without quicklime • Sintering of microstructure and cracks were observed in the exposed refractories • Mg 2 SiO 4 and CaMgSiO 4 formed in the refractories exposed to coal ash • Exposure of the refractory to a mixture of fuel ash and quicklime caused less slag intrusion than for exposure to only fuel ash • The refractory cold crushing strength was affected by all exposures and discussed in relation to changes in the microstructure [ABSTRACT FROM AUTHOR]

Corrosion resistance of refractory materials to the melt and slags is essential during scrap brass smelting. MgO-Cr 2 O 3 bricks exhibit remarkable high-temperature stability and corrosion resistance in the non-ferrous metallurgical industry. In this paper, the corrosion mechanism of MgO-Cr 2 O 3 bricks was explored by scrap brass slag. Through thermodynamic simulation, the possible chemical reactions were revealed between bricks and slag. Simultaneously, laboratory experiments were conducted to investigate the effects of temperature and time. The results showed that MgO-Cr 2 O 3 bricks were reacted with solid phase of ZnO, PbO, and Al 2 O 3 in slag, leading to the formation of CuAl 2 O 4 and MgAl 2 O 4. The bricks were deeply penetrated by liquid Cu and Zn through cracks and pores, resulting in the generation of PbO and ZnCr 2 O 4. Gas phases such as Zn vapor and HF vapor continued to infiltrate the interior and generate ZnCr 2 O 4. Especially, MgO serves as the main reactive substance in MgO-Cr 2 O 3 bricks. For every 100 °C improved in temperature, the corrosion mass increased by 0.003587 g/day. Besides, the time for an entire MgO-Cr 2 O 3 brick to be completely corroded at the average production temperature was 79.24 days. This paper introduces suggestions to refractory materials for scrap brass smelting. [ABSTRACT FROM AUTHOR]

Light, strong, and radiation-tolerant materials are essential for advanced nuclear systems and aerospace applications. However, the comprehensive properties of current radiation-tolerant materials are far from being satisfactory in harsh operating environments. In this study, a high-throughput-designed NbVTaSi refractory eutectic medium entropy alloy realizes the controllable formation of the β-Nb5Si3 phase with a high content and has outstanding comprehensive properties, i.e., lightweight, high yield strengths at room temperature and 850℃, and excellent He-ion irradiation resistance. According to density functional theory calculations and experimental findings, the prefabricated lattice distortion of the Nb50V42Ta8 phase leads to great phase stability under severe He-ion irradiation conditions, while the dual characteristics of the semi-coherent interface and hyperstatic lattice structure of the high-content β-Nb5Si3 phase dominate its outstanding He-ion irradiation resistance. This study sheds light on the design strategy for comprehensive properties and development of future radiation-tolerant materials for advanced nuclear systems and aerospace applications. [ABSTRACT FROM AUTHOR]

Background: Improving the understanding of how a refractory material responds to thermal shocks and allowing the validation of finite element models require a valuable tool for experimental data collection. Objective: This paper introduces an innovative, sophisticated, and highly reliable experimental device designed to apply a controlled cyclic thermal gradient in a disk-shaped ceramic refractory sample and to simultaneously monitor thermomechanical response and potential damage. Methods: This device, named Advanced measurements for in-situ Thermomechanical monitORing of large sample uNder thermal grAdient, is based on a CO2 laser beam to generate a calibrated thermal flux sequence at the top face while accurately measuring temperature field at the bottom face by an infrared camera. The displacement field of the bottom face is also continuously monitored by a stereo-vision system, enabling a precise measurement of 3D displacements and, thus, of the local strains. An accurate monitoring of the crack extension is performed thanks to the Two-Part Digital Image Correlation technique. Results: Throughout the thermal cycling sequence applied to an exemplar sample, the device has proved to be a robust and reliable system able to provide very accurate experiment data in terms of displacement, strain, temperature fields and crack length/opening. Conclusions: This device represents a significant advancement in in-situ monitoring of a refractory sample and contributes to the comprehensive characterization of materials under thermal gradients. More investigations and comparison with thermomechanical Finite Element modelling are shown in a second part of this paper. [ABSTRACT FROM AUTHOR]

Semi‐rebonded periclase‐chromite refractories are commonly utilized in the working lining section of the molten pool in oxygen‐enriched top‐blowing furnaces for nickel production. Its resistance to nickel slag corrosion determines the safety and service life of the melting furnace. The composition of nickel slag influences the corrosion resistance of semi‐rebonded periclase‐chromite refractories. By comparing and analyzing specimens corroded by primary and modified nickel slag, the influence mechanism of w(CaO)/w(SiO2) variations on corrosion resistance of semi‐rebonded periclase‐chromite refractories was clarified. The results show that a spinel isolation layer is preferred to form at a lower w(CaO)/w(SiO2) ratio (< 0.576) and enhance the corrosion resistance of semi‐rebonded periclase‐chromite refractories. As the ratio increases, the slag viscosity falls and the corrosion products contain larger levels of Ca3Cr2Si3O12 and Ca3MgSi2O8, which prevent the creation of the isolation layer and establish a conduit for Ca2+ and Si4+ transport and reaction into the interior of the refractory. [ABSTRACT FROM AUTHOR]

Fiberboard (FB) is extensively utilized in heat‐insulating refractory materials owing to its lightweight nature and excellent resistance to high temperatures. Nevertheless, the inadequate mechanical properties and limited dimensional stability of FB hinder its further application. The vacuum filtration was utilized in this study to manufacture inorganically modified insulation FB, incorporating plus fiber/1260 fiber and silica sol as the primary constituents and sepiolite powder (HS) as the modifier. The experimental results show that the fabricated samples exhibited extremely high porosity (75.3%–90.2%) and low thermal conductivity (.063–.15 W m−1 K−1, 200–800°C). The fibers were arranged in a three‐dimensional structure, overlapping with each other, and the silica sol adhered to the fibers, forming a spatial mesh structure through cross‐linking. Importantly, the incorporation of HS was effective in controlling the agglomeration of the silica sol, leading to a more uniform distribution within the fibers. Additionally, the study found that the mechanical properties (high hardness (64–72 HA)) and high‐temperature durability of the FBs were enhanced due to the flocculant modification. This study highlights promising prospects for industrial applications and offers a cost‐effective admixture for modifying and preparing high‐performance FBs, which is expected to see broad adoption in thermal insulation and energy conservation applications. [ABSTRACT FROM AUTHOR]

The rapid development of the power industry has resulted in a significant amount of electric porcelain solid waste. To address the challenges of small‐scale utilization and low added value associated with the current utilization of porcelain solid waste, a new high‐temperature resistant material was successfully developed using waste electric porcelain with varying particle sizes as the primary raw material. The dependence of composition, structure, and mechanical properties on fine particle size and sintering temperature was explored. The research has determined that the most effective particle size for the synthesis of refractory materials using waste electric porcelain is 120 mesh, and the optimal temperature is 1600°C. When the temperature exceeds 1500°C, the expansion generated by the decomposition of sillimanite will counteract the shrinkage of the liquid phase reaction, thereby maintaining the morphology of the sample. This process forms a unique interwoven mullite morphology through the decomposition of sillimanite, thereby enhancing the strength of the material. As a result, the optimal bending strength of 74 MPa and the optimal compression strength of 207 MPa were obtained. The realization of high‐temperature resistant materials based on discarded electric porcelain has shown foreseeable potential in large‐scale high‐value utilization. [ABSTRACT FROM AUTHOR]

MgO–C refractories are of paramount importance in the converter side blowing system, requiring outstanding oxidation resistance under harsh conditions including high temperature, oxygen atmosphere, and high‐speed airflow. In this study, MgSiN2 phase reconstruction was used to improve the oxidation resistance of MgO–C refractories, as well as the mechanical properties and oxidation resistance of MgO–C refractories were evaluated. The results indicated that the cold modulus of rupture of the sample with 9 wt% MgSiN2 was increased by 93.3% compared with the MgO–C refractories without MgSiN2. After oxidation tests, the oxidation index and rate constant (k) of the sample with 9 wt% MgSiN2 were reduced by 38.9% and 35.3%. Furthermore, incorporating MgSiN2 facilitated the formation of layered dense structures consisting of plate‐like Mg‐Sialon and MgO–Mg2SiO4–MgAl2O4. This structural optimization effectively inhibited oxygen diffusion and reaction within the material, resulting in gradual oxygen potential mitigation. [ABSTRACT FROM AUTHOR]

MgO–C refractories are of paramount importance in the converter side blowing system, requiring outstanding oxidation resistance under harsh conditions including high temperature, oxygen atmosphere, and high‐speed airflow. In this study, MgSiN2 phase reconstruction was used to improve the oxidation resistance of MgO–C refractories, as well as the mechanical properties and oxidation resistance of MgO–C refractories were evaluated. The results indicated that the cold modulus of rupture of the sample with 9 wt% MgSiN2 was increased by 93.3% compared with the MgO–C refractories without MgSiN2. After oxidation tests, the oxidation index and rate constant (k) of the sample with 9 wt% MgSiN2 were reduced by 38.9% and 35.3%. Furthermore, incorporating MgSiN2 facilitated the formation of layered dense structures consisting of plate‐like Mg‐Sialon and MgO–Mg2SiO4–MgAl2O4. This structural optimization effectively inhibited oxygen diffusion and reaction within the material, resulting in gradual oxygen potential mitigation. [ABSTRACT FROM AUTHOR]

This study aims to identify a novel area of use for metallurgical slags, which cause environmental problems. The usability of low-cost material with blast furnace slag (BFS) content in thermal spray coating technology and wear-based applications was investigated. For this purpose, the microstructural properties and wear performances of thermal spray coatings with 80Ni-20Cr content and coatings with BFS content currently used in commercially oriented applications were investigated in detail. The wear performance of the coatings was investigated under dry sliding conditions in ball-on-flat reciprocating tests using an Al2O3 ball as the counterpart. It was observed that the produced BFS coatings had a microstructural homogeneous structure and had porosity and oxide structure reflecting the traditional feature of the thermal spray coating process. It was determined that the hardness and surface roughness values of BFS coatings were higher than 80Ni-20Cr commercial coatings. As a result of the wear tests, it was observed that the wear performance of BFS coatings was higher than that of 80Ni-20Cr coatings and that oxidative, abrasive and adhesive wear mechanisms accompanied the wear failure formation. [ABSTRACT FROM AUTHOR]

Combining the advantages of both containing-B compounds and containing-Ti compounds, a new TiB 2 addition is proposed in MgO-C refractories. In this paper, the high-temperature oxidation behavior of low-carbon MgO-C refractories with TiB 2 addition was investigated, especially the effect of microstructure and phase evolution on the high-temperature oxidation behavior was discussed. The results show that in the materials, TiB 2 preferentially reacts with oxygen, forming TiC x N 1-x , Mg 3 (BO 3) 2 and Mg 2 TiO 4 ceramic phases, and catalyzing the decomposition of phenolic resin to form bamboo-like nanotubes and carbon nanospheres to bond aggregates and fill pores. Meanwhile, TiB 2 also promotes the formation of regenerated MgO compact zone, hindering the diffusion of oxygen into the materials to improve the oxidation resistance. Compared with the blank control specimen and the specimen with B 4 C addition, the oxidation resistance increased by 243.4 % and 79.2 %, respectively. [ABSTRACT FROM AUTHOR]

Thymic carcinoma (TC) is an uncommon type of thymic epithelial tumors. Patients with relapsed or refractory TCs have a poor prognosis. Immune checkpoint inhibitor monotherapy can be applied as a second-line treatment for such cases. This study reported a TC patient who did not respond to conventional chemotherapy and radiotherapy but achieved prolonged partial remission lasting 17 months following the third-line treatment with anti-programmed cell death-1 inhibitor sintilimab. This patient did not experience any serious side effects associated with sintilimab treatment. The above results demonstrated that sintilimab could be a feasible therapeutic option for refractory TC patients. [ABSTRACT FROM AUTHOR]

CaO-MgO-SiO 2 insulating refractories were prepared using phosphorus tailings through in-situ pore-forming technology in this work, aiming to achieve the efficient utilization of solid waste phosphorus tailings. microsilica was used to react with free CaO generated by the decomposition of dolomite from phosphorus tailings during the calcination in order to prevent the hydration of CaO in the materials. The influence of microsilica addition and heating temperature on the properties of insulating refractories prepared from phosphorus tailings was investigated. The results showed that CaO-MgO-SiO 2 insulating refractories with 8.8 wt% microsilica addition exhibited excellent comprehensive performance after heating at 1300 °C for 3 h. The insulation refractories prepared from phosphorus tailings were anti-hydration, had lower thermal conductivity, and could be used as insulation refractories for high-temperature kilns. [ABSTRACT FROM AUTHOR]

Muscle-specific kinase (MuSK) myasthenia gravis (MG) is relatively rare and has a higher incidence of myasthenic crisis compared with other subtypes. However, there is still a lack of effective treatment for refractory MuSK MG. We report the case of a 70-year-old female MuSK MG patient with recurrent fluctuations who stabilized on telitacicept in combination with anti-CD20 B-cell depletion therapy. This combination regimen deserves further investigation. Furthermore, we summarized the treatment protocols of 14 previously reported cases of MuSK MG. [ABSTRACT FROM AUTHOR]

Background: Lysophosphatidic acid (LPA) receptor 3 (LPA3) is involved in many physiological and pathophysiological actions of this bioactive lipid, particularly in cancer. The actions of LPA and oleoyl-methoxy glycerophosphothionate (OMPT) were compared in LPA3-transfected HEK 293 cells. Methods: Receptor phosphorylation, ERK 1/2 activation, LPA3-β-arrestin 2 interaction, and changes in intracellular calcium were analyzed. Results: Our data indicate that LPA and OMPT increased LPA3 phosphorylation, OMPT being considerably more potent than LPA. OMPT was also more potent than LPA to activate ERK 1/2. In contrast, OMPT was less effective in increasing intracellular calcium than LPA. The LPA-induced LPA3-β-arrestin 2 interaction was fast and robust, whereas that induced by OMPT was only detected at 60 min of incubation. LPA- and OMPT-induced receptor internalization was fast, but that induced by OMPT was more marked. LPA-induced internalization was blocked by Pitstop 2, whereas OMPT-induced receptor internalization was partially inhibited by Pitstop 2 and Filipin and entirely by the combination of both. When LPA-stimulated cells were rechallenged with 1 µM LPA, hardly any response was detected, i.e., a "refractory" state was induced. However, a conspicuous and robust response was observed if OMPT was used as the second stimulus. Conclusions: The differences in these agents' actions suggest that OMPT is a biased agonist. These findings suggest that two binding sites for these agonists might exist in the LPA3 receptor, one showing a very high affinity for OMPT and another likely shared by LPA and OMPT (structural analogs) with lower affinity. [ABSTRACT FROM AUTHOR]

The temperature and pressure conditions experienced by rocks during an impact event can be constrained using petrologic and microstructural analysis and is crucial to providing ground truth to the impact cratering process. Suevite is a polymict, impact melt‐bearing breccia, specific to Ries crater in Germany. There are competing models for suevite formation and emplacement, such as clastic flows pushed out of the crater rim or ejecta plume fallback. Knowledge of the temperature and pressure pathways recorded by grains within the suevite can help distinguish between these and other models. The accessory phase zircon (ZrSiO4) and its high‐pressure polymorph reidite are particularly useful in such circumstances as they are highly refractory minerals that can record the high‐temperature and/or high‐pressure conditions of an impact event. Here, we present evidence for a wide array of temperature and pressure conditions recorded in zircon grains within a single thin section of suevite. Zircons in this study range from unshocked to highly shocked (>53 GPa), and record temperatures more than 1673°C. These findings confirm previous studies concluding that suevites contain material exposed to very diverse pressure and temperature conditions during initial shock compression and excavation but do not, as a whole, experience extreme temperatures (>1673°C) or pressures (>30 GPa). [ABSTRACT FROM AUTHOR]

Cost-effective decarbonization and structural strengthening of carbon-containing refractory materials are crucial for the development of low-carbon steel (LCS) and ultra-low-carbon steel (ULCS) technologies. In this study, a carbonaceous-ceramic reinforcement assembly structure composed of multilayer graphenes and silicon carbide whiskers/particles (MLGs-SiC w /SiC p) has been successfully designed and fabricated. By employing three-roll milling (TRM) for low-cost exfoliation of expanded graphite (EG) into MLGs in a phenolic resin (PF) medium, we optimized the exfoliation cycles to fine-tune the morphology of MLGs. Subsequently, the catalytical solid-state conversion of PF/MLGs reacting with Si into SiC w /SiC p at 1400 °C, under varying C/Si molar ratios and catalyst contents, not only retained the structural integrity of MLGs but also embedded them within a novel SiC w /SiC p composite matrix. Our research elucidates the catalytic conversion mechanism, underscoring the significant role of nickel catalysts in promoting efficient SiC conversion. This work offers a promising pathway for developing high-performance, economical, low-carbon refractories. [ABSTRACT FROM AUTHOR]

Alumina-silica based refractories have found vast applications in various industries due to their strong resistance to corrosion and price advantages. In this research work high temperature corrosion resistance of aluminosilicate refractories against silicate melt was investigated. Various refractory brick matrices based on bauxite, chamotte and andalusite were prepared. The microstructure and chemical characteristics before and after corrosion cup test, as well as physical and mechanical properties were evaluated. The results indicated that corrosion resistance is increased in the following order of chamotte < bauxite < andalusite. Chemical composition and porosity were considered as determinant factors influencing corrosion process and mechanical properties of the refractory bricks. Low porosity of the andalusite aggregates raised the corrosion resistance by making limitations for melt infiltration into refractory material. Low mullitization of andalusite reduced the density and mechanical strength in comparison with other aluminosilicates. [ABSTRACT FROM AUTHOR]

Coatings based on refractory metals and compounds have been used in various industries since the last century due to their high thermal and heat resistance, as well as their excellent mechanical and tribological properties. Advances have made it possible to apply high-tech methods for their production, which has improved their availability and expanded their range of applications. A promising area of use of coatings based on refractory systems is the anticorrosion protection of structural materials. The high wear resistance and anticorrosion ability of these materials will allow for the protection of critical units of equipment of various industries from the complex destructive effects of factors of chemical and mechanical nature. For the effective choice of coating composition, it is necessary to know the basic characteristics of refractory material layers and the method of their production. The purpose of this article is to summarize modern scientific data on methods of obtaining refractory coatings, as well as on their composition, structure, and protective properties. The information presented in this review will bridge the gap between research and industrial development and expand the niche area of utilization. [ABSTRACT FROM AUTHOR]

Electric arc furnaces are commonly used in foamed slag technology for the production of steel from steel scrap through an electric process. The effects of using this technology include increased efficiency, reduced consumption of refractory materials, reduced energy consumption, reduced electrode wear, and improved arc stability. The world is constantly looking for solutions to optimize the feeding of the foaming agent to the electric furnace, including determining the moment of starting its feeding. The authors propose using two parameters to determine the optimal moment of introducing the foaming agent: the change in the sound level emitted by the arc furnace and the fluctuations in active power consumption. In order to determine the above parameters, tests were carried out on an industrial alternating UHP arc furnace with a capacity of 70 tons. The sound intensity level was determined at which the feeding of the foaming agent to the furnace's working space should begin. A moving coefficient of power consumption variation was developed and decision variables of the software for online foaming agent feeding were determined. As a result of implementing the developed solutions to the electric furnace control system and conducting comparative tests, savings were obtained in the form of reduced foaming agent consumption. [ABSTRACT FROM AUTHOR]

An important issue in obtaining a good casting surface without defects in contact with the liquid metal is the use of protective coatings on the surface of the moulding sand forming the mould cavity. Protective coatings are based on highly refractory materials that are finely ground and protect the moulding sand from thermal stresses from the molten metal. An important aspect of obtaining the appropriate properties of the protective coatings used is the method of application. This article presents the results of a quality study of the protective coatings obtained, which were applied by dip and painting with a brush. Four different coatings were applied to mould sand samples prepared on grain matrices with different average grain sizes. During the tests, the viscosity of the protective coatings, their gas-forming capacity, sieve analyses of the grain matrix used, the permeability of the moulding sand with the protective coating and the abrasiveness and adhesion of the protective coatings were determined. The quality of the coating obtained was found to depend on its type, the size of the grain matrix used in the moulding sand and the method of application. The experiments carried out indicate that a comparative study of the available protective coatings can indicate the best solution, taking into account the grain matrix used and the method of application adopted. [ABSTRACT FROM AUTHOR]

On the rising demand for eco‐friendly refractories, reducing the use of likely toxic magnesia‐chromium aggregates remains a challenge. Previous studies by some of the authors have proposed Cr‐free alternative compositions, although the morphology of the spinel precipitates has varied across the different suggested systems. The mechanisms involved in the formation of these distinct morphologies were unclear and, therefore, are the focus of this work. In all compositions, SEM/electron backscatter diffraction revealed cube–cube orientation relationships between matrix and precipitates, indicating that their formation is influenced by the lattice parameter misfit (δ), which was measured using synchrotron X‐ray diffraction. It could be concluded that coarser and spherical precipitates form to minimize their surface‐to‐volume ratio in compositions with high absolute δ‐values. Conversely, low‐misfit systems enable the spinel to form a 3D‐network. The potential use of this knowledge to tailor the microstructure of novel compositions was demonstrated by a small Nb2O5 addition into one of the proposed compositions. [ABSTRACT FROM AUTHOR]

The Ti2AlNb alloy is a refractory material with the potential to replace Ni-based alloys in the manufacturing process of aerospace engines. However, the development of this alloy is still in the research stage, requiring further investigation to promote its industrial application. Therefore, this paper provides an overview of the alloy, starting from its elemental composition and encompassing its microstructural morphology, fabrication processes, and mechanical properties. First, this paper presents the nine common alloying elements (Al, Nb, Mo, Zr, Fe, V, W, Ta, and Si), which play various roles in determining the alloy's microstructure and mechanical performance. Then, the paper presents three typical microstructures and the corresponding microstructure regulation processes, providing references for microstructure regulation. In the regulation process, although there are seven manufacturing processes (Casting, Forming under pressure, Machining, Welding and joining, Powder metallurgy, Additive manufacturing, and Surface treatment) currently applied to the industrialization of this alloy, certain shortcomings still exist, indicating significant research opportunities. Finally, the paper summarizes the relationships between the alloy's typical microstructures and its mechanical properties. In conclusion, the work presented in this paper offers a clear reference for advancing the industrial application of the alloy and encourages future researchers to contribute to the further development of this field based on the foundation established by this review. [ABSTRACT FROM AUTHOR]

X-ray computed tomography (XRT) has gradually established its position as a non-destructive and, therefore, reproducible three-dimensional (3D) investigation technique, allowing for material- and geometry-independent applications. In the context of this study, XRT provides an enhanced understanding of thermal-induced microstructural changes in an andalusite-based refractory, which are not apparent from the limited two-dimensionality of conventional optical investigation techniques. By subjecting an andalusite-based sample to an XRT scan after temperature treatments of T = 110 °C, 800 °C, 1000 °C, 1200 °C and 1400 °C, the XRT technique in this study introduced a novel perspective on the sintering process of andalusite refractory materials. The XRT investigation focused on the thermal-induced defect and crack evolution of the castable as a function of temperature. In addition to general sintering phenomena, this includes the formation of a capillary network filled with silica-rich glass phases (SiO2) due to the mullitization of andalusite. The results of the XRT analysis indicate the existence of glass bridges within these structures. [ABSTRACT FROM AUTHOR]

Reducing dependence on toxic electrofused magnesia‐chromium aggregates is essential to meet demands for eco‐friendly refractories. Some authors have proposed alternative compositions using lab‐scale electrofusion to produce small specimens (< 0.5 g). However, this size limits the evaluation of key refractory properties, such as thermal expansion. As an alternative, this study explored conventional sintering at 1600°C for 5 h and both methods resulted in equivalent chemical and mineralogical compositions. Despite presenting higher porosity (24 % – 30 %) than the electrofused ones (4 % – 6 %), consistent microstructural parameters supported using the sintering route to produce larger specimens (5 × 5 × 25 mm3), which were assessed for dilatometric profiles up to 1400°C. Combined with thermodynamic calculations, Rietveld's refining of X‐ray diffraction patterns and differential scanning calorimetry, the dilatometric analysis indicated that spinel dissolution in the periclase causes a high expansion during heating, whereas its re‐precipitation results in shrinkage. As this behavior could result in challenges for the refractory lining design, computational thermodynamics was used to find additives capable of increasing this transition temperature. TiO₂ was identified as a promising candidate and its effectiveness was attested. [ABSTRACT FROM AUTHOR]

Abstract Metasurface solar absorber serves as a kind of important component for green energy devices to convert solar electromagnetic waves into thermal energy. In this work, we design a new solar light absorber configuration that incorporates the titanium nitride substrate, aluminum oxide layer, titanium nitride layer, and the topmost refractory nanostructures. The metasurface absorber based on this configuration can achieve an average spectral absorption of over 91% and a total solar radiation absorption of 91.5% at ultra-wide wavelengths of 300–2500 nm. It is discovered that the excellent performance of the proposed metasurface absorber is attributed to the synergistic effects of surface plasmonic effect and Fabry–Pérot (FP) cavity resonance by comprehensive analysis of the simulated field distributions. Furthermore, the effect of geometrical parameter of the proposed configuration on absorber performance is studied, indicating the proposed configuration possesses a large fabrication tolerance. Moreover, the proposed configuration is not sensitive to the polarization direction and the angle of incident light. It is also found that the use of other refractory metal materials and other shapes as the topmost absorbent nanostructures also have good results with this configuration. This work can offer a universal platform for constructing and guiding the design of refractory metasurface solar absorbers.

Melting properties are critical for designing novel materials, especially for discovering high-performance, high-melting refractory materials. Experimental measurements of these properties are extremely challenging due to their high melting temperatures. Complementary theoretical predictions are, therefore, indispensable. One of the most accurate approaches for this purpose is the ab initio free-energy approach based on density functional theory (DFT). However, it generally involves expensive thermodynamic integration using ab initio molecular dynamic simulations. The high computational cost makes high-throughput calculations infeasible. Here, we propose a highly efficient DFT-based method aided by a specially designed machine learning potential. As the machine learning potential can closely reproduce the ab initio phase-space distribution, even for multi-component alloys, the costly thermodynamic integration can be fully substituted with more efficient free energy perturbation calculations. The method achieves overall savings of computational resources by 80% compared to current alternatives. We apply the method to the high-entropy alloy TaVCrW and calculate its melting properties, including the melting temperature, entropy and enthalpy of fusion, and volume change at the melting point. Additionally, the heat capacities of solid and liquid TaVCrW are calculated. The results agree reasonably with the CALPHAD extrapolated values. [ABSTRACT FROM AUTHOR]

The manufacture of products from refractory ceramics requires high temperatures due to the high activation energies of the sintering process of refractory oxides. Processing temperatures for ceramics made of ZrO 2 , Al 2 O 3 , MgO can be reduced if a flux or glass-forming component is selected. Furthermore, in multicomponent ceramics it is possible to create more favorable thermoresistive properties. This study examines the synthesis, structural, phase and mechanical properties of multicomponent porous ZrO 2 -WO 3 -Al 2 O 3 -MgO ceramics with varying weight concentrations of components. Experimental samples were obtained by standard solid state reaction method. The analysis of fabricated samples was carried out using X-ray phase analysis, scanning electron microscopy and the Vickers microhardness test. In this work, a new approach to increasing the microhardness of porous refractory ceramics is presented, in which WO 3 -based flux forms a matrix composed of glass-like formations that "attach" particles of ZrO 2 and MgAl 2 O 4 phases. The obtained ceramics demonstrates high microhardness values HV0.05 for porous materials ranging from 500 to 600. Studies have shown that the selected composition of multicomponent ceramics (x = 0.10–0.25) can be used as a refractory material up to temperatures of ∼1300 °C. The fabricated refractory ceramics potentially possess chemical stability and optimal microhardness properties, which makes these materials promising as a heat insulating lining in the metals, ceramics and glass manufacturing, as well as for components in the chemical industry. [ABSTRACT FROM AUTHOR]

The (Al 1-x Cr x) 2 O 3 solid solution (ACS) is expected to be an low pollution chromium source for high-performance alumina-chromium oxide refractory materials. In this work, the effects of Cr 2 O 3 content and reaction conditions on the solid solution behavior in the Al 2 O 3 -Cr 2 O 3 system were explored and the mechanism was revealed. The relationship between the lattice parameters of the formed ACS phase and the content of Cr 2 O 3 was closer to a linear one as the temperature rose, serving as an indicator for a higher degree of reaction. The solid solution reaction between Al 2 O 3 and Cr 2 O 3 was governed by the diffusion processes of Al3+ and Cr3+ at 1300–1500 °C and 1200 °C, respectively, and thus the increase of Cr 2 O 3 content slowed the solid solution reaction at a low temperature whereas promoted it at elevated temperatures. The diffusion process of solid solution reaction within the Al 2 O 3 -Cr 2 O 3 system was consistent with the Cater model; The diffusion activation energy (E a) decreased as the content of Cr 2 O 3 increased at 1300–1500 °C. When the content of Cr 2 O 3 increased from 25 to 60 mol%, the diffusion activation energy decreased from 92.48 to 86.49 kJ/mol−1, which was attributed to the augmentation in the diffusion rate of Cr3+ caused by the increase of Cr 2 O 3 content and its vapor-phase transport mechanism at high temperatures. [ABSTRACT FROM AUTHOR]

MgO-SiC-C refractories demonstrate distinguished thermal shock resistance and slag resistance, making them a promising alternative to magnesia-chrome refractories in matte smelting furnaces. Herein, we propose a novel approach to enhance both oxidation resistance and slag penetration resistance of such refractories by incorporating Si 3 N 4 -Fe powder. The results demonstrated that adding Si 3 N 4 -Fe powder effectively enhanced their overall performance. The oxidation resistance of the specimen with 6 wt% Si 3 N 4 -Fe was greatly improved because Si 3 N 4 in Si 3 N 4 -Fe could promote in-situ reactions to form more forsterite, and the FeO formed by iron oxidation could react with SiC to form Fe-Si alloys; the formed forsterite and Fe-Si alloys worked together to prevent oxygen intrusion. Meanwhile, Si 3 N 4 in Si 3 N 4 -Fe promoted the formation of forsterite layer in the corrosion area of refractories, and the reaction of Si 3 N 4 and Fe in Si 3 N 4 -Fe formed Fe-Si alloys to prevent slag penetration, which greatly improved the resistance to matte slag penetration of the refractories. [ABSTRACT FROM AUTHOR]

This study investigated the degradation mechanisms of SiC-MgAl 2 O 4 refractory materials in a bench-scale entrained flow gasifier. Layered degradation and protective SiO 2 formation on SiC aggregates were observed by macroscopic, microscopic, phase analysis, and thermodynamic calculations. A comparative investigation of erosion rates revealed that SiC-MgAl 2 O 4 materials located away from the burner had an unusually low erosion rate of 0.0017 mm/h, which was significantly lower than that reported in their counterparts situated near the burner (0.0167 mm/h). This performance surpassed even that of high-chrome refractory materials positioned at a similar distance from the burner. The findings underscore the remarkable durability of SiC-MgAl 2 O 4 , demonstrating its significant potential as a sustainable and chrome-free alternative for application in harsh gasification conditions. The environment-specific degradation patterns, characterized by the formation of mullite and cordierite, revealed the complex interaction between refractory materials and gasification environments. This understanding offers valuable insights that can inform the development and implementation of chrome-free refractory materials under industrial gasification conditions. [ABSTRACT FROM AUTHOR]

Pyrometallurgical recycling of lithium-ion batteries (LIB) has emerged as the go-to approach in industrial recycling solutions, yet it encounters significant challenges, such as lithium (Li) slagging. This study explores a reactor for pyrometallurgical recycling, that offers the potential to overcome this bottleneck by simultaneously recovering lithium and phosphorous (P) via the gas stream, more noble elements including cobalt (Co), nickel (Ni) and copper (Cu) as an alloy and less noble elements like aluminum (Al), calcium (Ca) and silicium (Si) as a slag. However, to enhance the efficiency and performance of this reactor, a critical focus is placed on evaluating refractory materials with reduced corrosion and diffusion characteristics. Already explored refractory materials, including aluminum oxide (Al 2 O 3) or magnesium oxide (MgO), have exhibited severe issues, such as accelerated corrosion and diffusion rates, leading to diminished performance and compromised efficiency. To evaluate a more suitable refractory material for pyrometallurgical recycling of LIB, tests using silicon carbide (SiC), chromium(III)-oxide (Cr 2 O 3) and zirconium dioxide (ZrO 2) were performed up to 1600 °C. The test results indicate that the investigated refractory materials offer distinct advantages and disadvantages. While SiC shows minimal to no wear by corrosion, Cr 2 O 3 exhibits higher resistance to Li diffusion. Contrary, ZrO 2 experienced severe corrosion and crack formation, showing unsuitability for LIB recycling. Based on these findings, a continuously operated reactor could use different refractory materials in specific zones. While the degasification zone could benefit from Cr 2 O 3 's minimal diffusion properties, areas with intense contact between the crucible and melt could utilize SiC's corrosion resistance. However, partial oxidation at the outer surface of the SiC crucible led to the formation of SiO 2 , another critical point to consider for scale-up plans, as it might influence the mechanical integrity long-term. [ABSTRACT FROM AUTHOR]

Protein Ser/Thr phosphatase PP1 is always associated with one or two regulatory subunits or RIPPOs. One of the earliest evolved RIPPOs is PPP1R2, also known as Inhibitor-2. Since its discovery nearly 5 decades ago, PPP1R2 has been variously described as an inhibitor, activator or (metal) chaperone of PP1, but it is still unknown how PPP1R2 affects the function of PP1 in intact cells. Here, using specific research tools, we demonstrate that PPP1R2 stabilises a subgroup of PP1 holoenzymes, exemplified by PP1:RepoMan, thereby promoting the dephosphorylation of their substrates. Mechanistically, the recruitment of PPP1R2 disrupts an inhibitory, fuzzy interaction between the C-terminal tail and catalytic domain of PP1, and generates an additional C-terminal RepoMan-interaction site. The resulting holoenzyme is further stabilized by a direct PPP1R2:RepoMan interaction, which renders it refractory to competitive disruption by RIPPOs that do not interact with PPP1R2. Our data demonstrate that PPP1R2 modulates the function of PP1 by altering the balance between holoenzymes through stabilisation of specific subunit interactions. PPP1R2, also known as Inhibitor-2, is a regulator of PP1 with an elusive function. Here, the authors show that PPP1R2 functions as an additional subunit of a subset of PP1 holoenzymes, thereby promoting the dephosphorylation of their substrates through stabilization of subunit interactions. [ABSTRACT FROM AUTHOR]

High-purity magnesia refractories were fabricated by brine magnesium hydroxide from the salt-lake brine (Qinghai Salt Lake) and Y 2 O 3 as an additive at 1780 °C. It avoided the substantial CO 2 emissions and ultra high temperature sintering process (＞1900 °C) when compared with the conventional magnesite-calcination technical approach. The results confirmed that Y 2 O 3 was dispersed on the MgO grains boundaries in the fabricated MgO aggregates, resulting in a decrease in apparent porosity and enhancing the grains' boundaries. With 3 wt% addition of Y 2 O 3 , the apparent porosity and bulk density of the sample reached to 15.9 % and 3.10 g/cm3 from 37.9 % to 2.30 g/cm3 of blank control group, respectively. Compared to the blank control without Y 2 O 3 -adding, the sample with 5 wt% Y 2 O 3 exhibited a 54.17 % increase in the resistance to molten slag. SEM results indicated that the incorporation of Y 2 O 3 in samples increased the porosity of small pores and enhanced grains boundaries, thereby suppressing slag's penetration. Furthermore, the Y 2 O 3 -adding was employed to disperse the MgO grains boundaries and existed as separate phases for grains boundaries enhancement. The slag attack of the fabricated MgO–Y 2 O 3 refractory raw materials were controlled by an inter-crystalline corrosion process. [ABSTRACT FROM AUTHOR]

The valorization of slag from the production of high-carbon ferrochrome is a challenge for ferrochrome producers. The recycling of high-carbon ferrochrome slag was explored through the smelting route to recover Fe–Si–Al–Cr alloys and reengineer the residual slag for alumina-enriched refractory material. In this research, the focus was to reduce the SiO2% and enrichment of Al2O3% in the final slag and recover the metallic value in the form of a complex alloy containing Fe, Si, Cr and Al. The manuscript consists of a thermochemical simulation of the smelting of FeCr slag followed by smelting experiments to optimize the process parameters such as temperature and the addition of coke, cast iron and alumina. An experimental investigation revealed that the maximum recovery of Si (57.4% recovery), Al in the alloy (20.56% recovery) and Al2O3 (85.78% recovery) in the slag was achieved at a charge mix consisting of 1000 g of FeCr slag, 300 g of alumina, 200 g of cast iron and 300 g of coke. The present study also demonstrated the usefulness of prior thermochemical calculations for smelting metallurgical wastes such as slag from high-carbon ferrochrome production for value creation and reutilization purposes. [ABSTRACT FROM AUTHOR]

Uruguayan philosopher Carlos Vaz Ferreira published in 1910 Lógica viva, his main philosophical work. In it he presents a logical exploration program, its foundations and some of its applications. As part of these, he studies various paralogisms which can be enhanced by appealing to a methodology that I called "model M". But this model does not manage to cover all the paralogisms proposed by Vaz. Other types of stereotyped errors are refractory to such treatment, which I call non-argument paralogisms; for example, false precision. In this paper I will suggest an alternative model M* and apply it to false precision. [ABSTRACT FROM AUTHOR]

This study deals with the design and development of a new generation of MgO–C refractory material implementing spent MgO–C recyclate as a partial replacement of fresh raw materials, and a non-hazardous environment-friendly lactose- and tannin-based binder system. Throughout the experimental campaign the used MgO–C recyclate, which was received in three size fractions, was analysed, and building on the obtained results, multiple batches of various compositions of next-generation MgO–C bulks were prepared. These bulks varied in the ratio between the individual size fractions of the MgO–C recyclate, the ratio between the individual binder components and the amount of water used during the preparation of the raw material batches. The bulk samples were prepared in the form of cylinders through uniaxial pressing, cured and coked, and studied in terms of their cold crushing strength, microstructural parameters, thermal behaviour, residual carbon content, and microstructure. The proposed next generation of MgO–C composites represents a potential eco-friendly alternative to MgO–C refractories prepared from traditional raw materials while utilizing waste material which would otherwise end up landfilled. [ABSTRACT FROM AUTHOR]

Key Clinical Message: This unique case of generalized myasthenia gravis shows sustained stability of a patient's condition for 3 years with eculizumab/ravulizumab treatment following 16 years of refractory disease. It highlights the long‐term effectiveness of C5 inhibitors in a real‐world setting, aiding physicians in their decision‐making for refractory cases and treatment discontinuation scenarios. [ABSTRACT FROM AUTHOR]

The corrosion of slag on refractories usually starts from the matrix, so improving the slag resistance of the matrix is of great significance for the slag resistance of the refractories. To clarify the influence of matrix on the slag resistance of magnesia–carbon refractories, the slag corrosion experiments were conducted at 1873 K on MgO–C refractories, low‐carbon MgO–C refractories, and MgO–SiC–C refractories. The results showed that the slag resistance of MgO–C refractories was higher than that of low‐carbon MgO–C refractories, and the slag resistance of MgO–SiC–C refractories was superior to that of low‐carbon MgO–C refractories. The interaction between MgO–SiC–C refractories and slag generated high melting point phases such as forsterite and spinel, reducing the routes for the slag to infiltrate the inside of the refractories. MgO–SiC–C refractories reacted with slag to increase the viscosity of the slag, the viscosity being 86.3% and 51.9% higher than in the case of low‐carbon MgO–C and MgO–C refractories, respectively. Compared with MgO–SiC–C refractories, MgO–C refractories did not exhibit overwhelming advantages in slag resistance. Due to the low‐carbon content and good slag resistance, MgO–SiC–C refractories were promising low‐carbon magnesia‐based refractories for high‐temperature industries. [ABSTRACT FROM AUTHOR]

Chromium–corundum, as a common refractory material, is broadly applied in high‐temperature kilns due to its superior thermal stability and high melting point. Unfortunately, this refractory is susceptible to corrosion and destruction under extreme furnace conditions by chemical erosion, mechanical wear, and thermal shock, which significantly shortens its useful life. Accordingly, in recent years, the issue of how to improve the slag corrosion resistance, mechanical, and sintering properties of chromium–corundum refractories has aroused widespread attention. In this work, the corrosion behavior and application status of chromium–corundum refractories in Ausmelt furnace, waste incinerator, coal water slurry gasifier, and HImelt melting reduction furnace are analyzed and discussed. To improve the service life of chromium–corundum refractories, the enhancement method and mechanism of sintering performance, mechanical properties, slag corrosion resistance, and thermal shock resistance are also summarized. Finally, some suggestions and prospects are made for the enhancement and longevity of chromium–corundum refractories. [ABSTRACT FROM AUTHOR]

Oxygen produced through in‐situ resource utilization (ISRU) is critical to maintaining a permanent human presence on the lunar surface. Molten regolith electrolysis and carbothermal reduction are two promising ISRU techniques for generating oxygen directly from lunar regolith, which is primarily a mixture of oxide minerals; however, both processes require operating temperatures of 1600°C to melt lunar regolith and dissociate the molten oxides. These conditions limit the use of many oxide refractory materials, such as Al2O3 and MgO, due to rapid degradation resulting from reactions between the refractory materials and molten lunar regolith. Yttria‐stabilized zirconia (YSZ) is shown here to be a promising refractory oxide to provide containment of molten regolith while demonstrating limited reactivity. This work focuses on corrosion studies of YSZ powders and dense YSZ crucibles in contact with molten lunar maria and highlands regolith simulants at 1600°C. The interactions between YSZ and molten regolith were characterized using scanning electron microscopy/energy dispersive spectroscopy, X‐ray diffraction, and electron backscatter diffraction. A FactSage thermochemical model was created for comparison with the experimental results. These combined analyses suggest that lunar maria regolith will degrade the YSZ faster than the lunar highlands regolith due to the lower viscosity of the maria regolith. The feasibility of long‐term molten regolith containment with YSZ is discussed based on the YSZ powder and crucible results. [ABSTRACT FROM AUTHOR]

To investigate the dynamic interaction between refining refractory and low‐carbon low‐silicon Al‐killed steel, the "refractory‐molten steel‐inclusion" system was analyzed using dynamic erosion experiments and the FactSage database. This study discussed the formation of interfacial layers between various refining refractories and molten steel, as well as the transformation of nonmetallic inclusions in steel. The findings indicate that the interaction between refractories and molten steel produces a distinct interface layer. The influence of various refining refractories on inclusions varies significantly. MgO‐C refractory promotes the formation of MgO·Al2O3 inclusions in steel, while Al2O3‐MgO refractory leads to the formation of SiO2‐MnO‐Al2O3 inclusions. Both Al2O3‐SiC refractory and Al2O3‐MgO‐C refractory result in Al2O3 inclusions with trace levels of MgO. Steel refined with Al2O3‐MgO‐C refractory has increased MgO content within Al2O3 inclusions but still does not reach the stoichiometric ratio of MgO·Al2O3. As the initial Al content increases, the influence of MgO‐C refractory inclusions becomes increasingly noticeable. The average MgO content within the inclusions rises with the reaction duration, achieving as high as 62.9%. The transition path of Al2O3 inclusions in molten steel follows "Al2O3→MgO·Al2O3→MgO." [ABSTRACT FROM AUTHOR]

The investment casting of titanium and its alloys relies on a high resistance of the crucibles and shell molds in terms of temperature and reactivity. The availability of ceramic crucibles that offer sufficient resistance to the titanium melt enables vacuum induction melting (VIM). CaZrO3 prepared from a mixture of CaO and ZrO2 as a raw material for refractory ceramics shows a high corrosion resistance against metallic melts even under very high temperatures up to 1800 °C. Crucibles and shell molds of CaZrO3 were successfully produced and used in subsequent casting trials. This study is focused on the refractory crucibles suitable for casting Ti-6Al-4V (Ti-64) using a tilt casting machine. In order to evaluate the crucible reaction and, therefore, the quality of the castings, chemical analyses, investigations of the microstructures and hardness measurements were carried out. Careful control of the melting duration is mandatory to avoid crucible reactions that otherwise result in contamination of the cast with oxygen and zirconium. This was achieved by modified coil geometries. Under optimized casting conditions, the oxygen and zirconium impurity limits of ASTM B367-09 for titanium castings were met. Based on the correlations found, optimized casting parameters with regard to material quantity, coil geometry and heating power could be determined in order to provide guidance for a high-quality casting process with VIM. [ABSTRACT FROM AUTHOR]

Electrochemical devices based on proton conducting ceramic oxides have shown a high potential for conversion processes at intermediate temperatures. In these cells, perovskite ceramics like BaZr 0.7 Ce 0.2 Y 0.1 O 3-δ (BZCY), which are based on the solid solution of BaZrO 3 and BaCeO 3 doped with Y, have proven to be a good compromise between chemical stability and proton conductivity. However, the refractory nature of this material system requires high sintering temperatures to enable dense ceramic membrane layers. Recently, a novel processing route, which applies the cold sintering process (CSP) as a pre-densification step has been developed allowing to lower the sintering temperatures while maintaining excellent electrochemical properties. In this study, we further improved this method by implementing a BZCY/NiO support layer for BZCY. After final thermal treatment under reducing conditions, a dense BZCY membrane supported by a porous BZCY/Ni electrode support resulted. We show that using powder processing techniques, it is possible to sinter thick layered structures, consisting of an almost dense, phase pure perovskite BZCY layer and a porous BZCY/NiO layer. Furthermore , the NiO phase was successfully reduced to Ni by an additional thermal treatment at 900 °C in Ar/H 2. The focus of this study was to generally prove the feasibility of applying co-cold sintering for the processing of layered ceramic architectures, which can be used – after further optimization of the processing – as electrode supported fuel or electrolysis cells. [ABSTRACT FROM AUTHOR]