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Xilinhot City is a significant pastoral city in China where groundwater serves as the primary water source for the cold and arid pastoral regions. The formation and evolution of material components in groundwater, as well as groundwater quality, are directly linked to the health of pastoral residents. This study is based on the physical and chemical test results of 22 groundwater samples collected from the Xilinhot River Basin in Inner Mongolia. Various statistical analyses, including Piper and Chadha diagrams, as well as hydrogeochemical simulation methods, were employed to assess the hydrogeochemical characteristics and material composition sources of groundwater, evaluate groundwater quality and non-carcinogenic risks, and comprehensively discuss the impact of macro- and microelements on human health. The findings indicate that igneous rocks containing minerals such as potassium feldspar, plagioclase, and pyroxene contribute Na+, Cl−, and K+ to the groundwater, while sedimentary rocks containing minerals like dolomite and calcite supply ions such as Ca2+, Mg2+, and HCO3−. The groundwater quality is primarily classified as Class II–V, with F− and NO3− exhibiting varying hazard quotients for children and adults in the study area, though they do not pose a non-carcinogenic risk. Additionally, the enrichment of hardness, Ca2+, Mg2+, Na+, SO42−, and other indicators in localized areas exceeds the recommended values for drinking water, potentially impacting the digestive and urinary systems of the human body. There is a risk of excessive fluoride in areas where F levels exceed 1 mg/L. Furthermore, the content of beneficial micronutrients such as selenium (Se), zinc (Zn), boron (B), and germanium (Ge) is relatively low. Based on the elemental abundance characteristics and a comparative analysis of the chemical properties of groundwater across five regions of China, this comparison facilitates a discussion on the definition of healthy groundwater, particularly in relation to safe consumption in cold and arid regions. This study aims to highlight the health issues associated with drinking groundwater in the cold and arid regions of Mongolia. The findings serve as a valuable reference for efforts aimed at reducing the incidence of endemic diseases and enhancing human lifespan. [ABSTRACT FROM AUTHOR]

Digital light processing (DLP) provides a promising avenue for constructing ceramic parts with high precision and complex shapes, yet the inherent brittleness and strength‐toughness trade‐off hinder their wide applications. Here, according to DLP 3D printing, the textured alumina ceramic components with horizontally aligned textured microstructure were successfully created by adding anisotropically shaped platelets. As a critical process in the preparation of textured ceramics, the alumina platelets were aligned horizontally during printing by using the special shear fields and forming capabilities of DLP technology. The shrinkage, density, microstructure, mechanical performance, and damage‐tolerance behavior of alumina parts with different platelet concentrations were examined, and the toughening mechanisms were investigated. The strength and toughness of ceramics with 5 vol.% platelet addition are increased by 22% and 43%, respectively, as compared with those without platelets. The improved damage tolerance capabilities were primarily ascribed to the collaborative toughening mechanisms stimulated by the platelet addition, including crack branching, crack deflection, uncracked‐ligament bridging, and platelet pull‐out, which increased the crack tortuosity and consumed more fracture energy. The strategy opens up new opportunities to design complex 3D ceramic geometries with bio‐inspired layered or textured architectures, providing optimized damage tolerance. [ABSTRACT FROM AUTHOR]

Si3N4 ceramics with high mechanical properties and thermal conductivity, exhibiting fine and bimodal microstructure, were prepared by adjusting the Er2O3/MgO ratio and hot‐pressing sintering at 1800°C for 4 h. The microstructure, grain distribution, lattice oxygen content, mechanical properties, and crack propagation process of the sintered bulk samples were systematically investigated. It was found that a low Er2O3/MgO ratio contributed to the densification of Si3N4 ceramics, whereas a high Er2O3/MgO ratio favored the grain growth of Si3N4 ceramics. In this research, the grain size distribution and average diameters as well as their impact on mechanical properties were examined. When the ratio of Er2O3/MgO was 3:1, Si3N4 had a larger average diameter and higher thermal conductivity, but the mechanical properties were somewhat reduced. When the ratio of Er2O3/MgO was 2:2, the sample displayed enhanced mechanical performance, which can be explained by the formation of a bimodal structure. The research indicates that it is feasible to control the microstructure and optimize the mechanical properties of Si3N4 ceramics by tailoring the sintering additives. [ABSTRACT FROM AUTHOR]

As the international situation continues to change and conflicts in various countries intensify, improving national defense forces is a necessary condition to ensure the stable development of the country, and bulletproof armor is a key part of it. Pressureless sintered silicon carbide ceramics have been widely used in the field of bulletproof armor because of its simple preparation process and excellent mechanical properties of low density, high hardness and high strength. The hardness and fracture toughness of pressureless sintered silicon carbide bulletproof ceramics directly determine the quality of bulletproof performance. Promoting sintering densification and multi-phase composite sintering are the key ways to improve the hardness and fracture toughness of pressureless sintered silicon carbide ceramics. This sturdy summarizes the research progress of pressureless sintered silicon carbide bulletproof ceramic materials in recent years, focusing on the sintering aids, toughening methods, composite form of pressureless sintered silicon carbide bulletproof ceramic materials. [ABSTRACT FROM AUTHOR]

A novel DC-assisted fast hot-pressing (FHP) powder sintering technique was utilized to prepare Al/Diamond composites. Three series of orthogonal experiments were designed and conducted to explore the effects of sintering temperature, sintering pressure, and holding time on the thermal conductivity (TC) and sintering mechanism of an Al-50Diamond composite. Improper sintering temperatures dramatically degraded the TC, as relatively low temperatures (≤520 °C) led to the retention of a large number of pores, while higher temperatures (≥600 °C) caused unavoidable debonding cracks. Excessive pressure (≥100 MPa) induced lattice distortion and the accumulation of dislocations, whereas a prolonged holding time (≥20 min) would most likely cause the Al phase to aggregate into clusters due to surface tension. The optimal process parameters for the preparation of Al-50diamond composites by the FHP method were 560 °C-80 MPa-10 min, corresponding to a density and TC of 3.09 g cm−3 and 527.8 W m−1 K−1, respectively. Structural defects such as pores, dislocations, debonding cracks, and agglomerations within the composite strongly enhance the interfacial thermal resistance (ITR), thereby deteriorating TC performance. Considering the ITR of the binary solid-phase composite, the Hasselman–Johnson model can more accurately predict the TC of Al-50diamond composites for FHP technology under an optimal process with a 3.4% error rate (509.6 W m−1 K−1 to 527.8 W m−1 K−1). The theoretical thermal conductivity of the binary composites estimated by data modeling (Hasselman–Johnson Model, etc.) matches well with the actual thermal conductivity of the sintered samples using the FHP method. [ABSTRACT FROM AUTHOR]

The microstructure design is important for regulating the microwave dielectric properties of materials. However, in‐depth studies on the frequency temperature stability and related micromechanism remain poorly understood. The work investigates the correlation among the sintering behavior, crystal structure, bonding nature, and microwave dielectric properties of LnPO4 (Ln = Eu, Pr) ceramics by combining first‐principles calculations and experimental perspective. The high density (ρ > 97%) and large grains associated with lattice expansion benefit the optimum dielectric properties: εr = 11.24, Q×f = 61,138 GHz @ 13.311 GHz, and τf = −30.3 ppm/°C for EuPO4 sintered at 1500°C (εr = 11.35, Q×f = 63,496 GHz @ 13.042 GHz and τf = −39.5 ppm/°C for PrPO4 sintered at 1525°C). Bond valence analysis shows a rattling effect in [EuO9] due to a smaller ionic radius. The effect induces an abnormally large polarization, effectively shifting the negative τf toward near‐zero values. The electron localization functions, charge transfer, and bonding nature are discussed by density functional theory calculations, which illustrate stronger charge transfer and ionicity between Eu and O. This observation effectively predicts and validates the nonharmonic lattice vibrations and abnormally large polarization obtained from Raman spectrums and Rietveld refinement. These findings systematically clarify the optimized effect and micromechanism of lanthanides on the dielectric properties of monazite ceramics. [ABSTRACT FROM AUTHOR]