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The electrochromic (EC) polymer poly (3,4‐(2,2‐dimethylpropylenedioxy)thiophene) (PProDOT‐Me2) is expected to be used in flexible e‐paper displays because of its great optical modulation ability and inherent flexibility. While the EC effect is primarily determined by the anions and cations in the electrolyte, yet suffers from inorganic salt based on monovalent Li+ cations and corresponding anions, such as lithium perchlorate(LiClO4), lithium bis(trifluoromethane sulfonyl) imide (LiTFSI), and lithium trifluoromethane sulfonate (LiTRIF), which may impact the overall EC performance of the EC device caused by insufficient ion doping/de‐doping processes. Herein, the divalent viologen cation‐based ionogel (VGE) is developed to tackle the challenge. Owing to its more anions design, the doping/de‐doping process in the PProDOT‐Me2 is more sufficient, thereby enhancing the optical modulation range (ΔR = 39.4%) of PProDOT‐Me2, compared to monovalent Li+ cation‐based ionogel (ΔR = 13.3%). Meanwhile, the VGE has good interface contact with PProDOT‐Me2 and the flexible electrode, which makes the VGE‐based EC device (V‐ECD) exhibit commendable mechanical stability. To demonstrate the potential application in flexible e‐paper displays, the simple eight‐digit EC display device is assembled from seven V‐ECDs, each of which hasa high switching speed, robust cycling stability, and low operating energy consumption. [ABSTRACT FROM AUTHOR]

Amid chairside CAD/CAM materials, the use of lithium-based silicate glass–ceramics (LSGC) has been steadily increasing. This review aims to report on the translucency of these materials and the variables used to measure it. An electronic search was performed within the PubMed database within the period between 2 June 2011 and 11 September 2022. English-language papers investigating the translucency of IPS e.max CAD, Celtra Duo, Suprinity PC, Initial LiSi Block, Amber Mill, N!ce, and CEREC Tessera LSGC CAD/blocks were included in the search strategy. After an initial retrieval of 160 papers, the application of exclusion criteria, and the screening of abstracts and then of full texts, 33 papers were included in the study. The retrieved materials, with different degrees of translucency (LT, HT), were IPS e.max CAD (n = 33), Suprinity PC (n = 8), and Celtra Duo (n = 1). Concerning the examined colors, the most used was A2 (n = 20), followed by A1 (n = 8) and A3 (n = 2). The translucency parameter (TP) was the most used method (n = 30) with respect to the contrast ratio (CR) (n = 11) to assess translucency. Five papers measured both. Several specimens' thicknesses (0.5–4 mm) were investigated, with 1 mm (n = 23) being the most frequently analyzed. While a general tendency could be identified, conflicting results among different papers were reported. [ABSTRACT FROM AUTHOR]

Until quite recently, in almost all papers on crystal nucleation in glass-forming substances, it was assumed that nucleation proceeds in a completely relaxed supercooled liquid and, hence, at constant values of the critical parameters determining the nucleation rate for any given set of temperature, pressure, and composition. Here, we analyze the validity of this hypothesis for a model system by studying nucleation in a lithium silicate glass treated for very long times (up to 250 days) in deeply supercooled states, reaching 60 K below the laboratory glass transition temperature, Tg. At all temperatures in the considered range, T < Tg, we observed an enormous difference between the experimental number of nucleated crystals, N(t), and its theoretically expected value computed by assuming the metastable state of the relaxing glass has been reached. Analyzing the origin of this discrepancy, we confirmed that the key parameters determining the nucleation rates change with time as a result of the glass relaxation process. Finally, we demonstrate that, for temperatures below 683 K, this particular glass almost fully crystallizes prior to reaching the ultimate steady-state nucleation regime (e.g., at 663 K, it would take 176 years for the glass to reach 99% crystallization, while 2600 years would be needed for complete relaxation). This comprehensive study proves that structural relaxation strongly affects crystal nucleation in deeply supercooled states at temperatures well below Tg; hence, this phenomenon has to be accounted for in any crystal nucleation model. [ABSTRACT FROM AUTHOR]

The incidence of microbial infections in orthopedic prosthetic surgeries is a perennial problem that increases morbidity and mortality, representing one of the major complications of such medical interventions. The emergence of novel technologies, especially 3D printing, represents a promising avenue of development for reducing the risk of such eventualities. There are already a host of biomaterials, suitable for 3D printing, that are being tested for antimicrobial properties when they are coated with bioactive compounds, such as antibiotics, or combined with hydrogels with antimicrobial and antioxidant properties, such as chitosan and metal nanoparticles, among others. The materials discussed in the context of this paper comprise beta-tricalcium phosphate (β-TCP), biphasic calcium phosphate (BCP), hydroxyapatite, lithium disilicate glass, polyetheretherketone (PEEK), poly(propylene fumarate) (PPF), poly(trimethylene carbonate) (PTMC), and zirconia. While the recent research results are promising, further development is required to address the increasing antibiotic resistance exhibited by several common pathogens, the potential for fungal infections, and the potential toxicity of some metal nanoparticles. Other solutions, like the incorporation of phytochemicals, should also be explored. Incorporating artificial intelligence (AI) in the development of certain orthopedic implants and the potential use of AI against bacterial infections might represent viable solutions to these problems. Finally, there are some legal considerations associated with the use of biomaterials and the widespread use of 3D printing, which must be taken into account. [ABSTRACT FROM AUTHOR]

Molecule self-assembly on the surface of alumina ceramic and its influence on the surface flashover characteristics of the alumina ceramic insulators were studied in this paper. First, octadecyltrichlorosilane was assembled on the surface of alumina ceramic insulators in the toluene solution. Then, 393 K thermal treatment of 2 h was conducted on the specimens to promote the growth of the molecule membrane. Quality detection of the prepared molecule membrane by Energy Dispersive x-ray Analysis and water contact angle test showed that the molecules were linked to the alumina surface and the arrangement of the molecules on the surface was regular and tight. Gas release characteristic suggested that the formation of the molecule membrane made the gas release rate of the treated alumina decrease. The flashover voltage test on the home-made, short-pulsed, high-voltage vacuum platform indicated that the flashover voltages of the treated insulators increased by over 200% compared with the original alumina insulators. These results indicated that a layer of regular molecule membrane was formed on the surface of alumina through molecule self-assembly, which could improve the surface voltage withstand strength of the treated insulators. [ABSTRACT FROM AUTHOR]

This research paper investigates the influence of varying silicon oxide (SiO x ) content on the performance and aging of lithium-ion cells. In-depth investigations encompass charge and discharge curves, thickness changes, electrolyte degradation, gas evolution, and chemical analysis of cells with different silicon oxide proportions in the anode and their associated cathodes. The results show that a higher silicon oxide content in the anode increases the voltage hysteresis between charge and discharge. Moreover, the first-cycle efficiencies decrease with a higher silicon oxide content, attributed to irreversible Li x Si y formation and the subsequent loss of active lithium from the cathode during formation. The anodes experience higher thickness changes with increased silicon oxide content, and peaks in differential voltage curves can be correlated with specific anode active materials and their thickness change. A gas analysis reveals conductive salt and electrolyte intermediates as well as silicon-containing gaseous fragments, indicating continuous electrolyte decomposition and silicon oxide aging, respectively. Additionally, a chemical analysis confirms increased silicon-derived products and electrolyte degradation on electrode surfaces. These findings underscore the importance of a holistic aging investigation and help understand the complex chemical changes in electrode materials for designing efficient and durable lithium-ion cells. [ABSTRACT FROM AUTHOR]

Until quite recently, in almost all papers on crystal nucleation in glass-forming substances, it was assumed that nucleation proceeds in a completely relaxed supercooled liquid and, hence, at constant values of the critical parameters determining the nucleation rate for any given set of temperature, pressure, and composition. Here, we analyze the validity of this hypothesis for a model system by studying nucleation in a lithium silicate glass treated for very long times (up to 250 days) in deeply supercooled states, reaching 60 K below the laboratory glass transition temperature, Tg. At all temperatures in the considered range, T < Tg, we observed an enormous difference between the experimental number of nucleated crystals, N(t), and its theoretically expected value computed by assuming the metastable state of the relaxing glass has been reached. Analyzing the origin of this discrepancy, we confirmed that the key parameters determining the nucleation rates change with time as a result of the glass relaxation process. Finally, we demonstrate that, for temperatures below 683 K, this particular glass almost fully crystallizes prior to reaching the ultimate steady-state nucleation regime (e.g., at 663 K, it would take 176 years for the glass to reach 99% crystallization, while 2600 years would be needed for complete relaxation). This comprehensive study proves that structural relaxation strongly affects crystal nucleation in deeply supercooled states at temperatures well below Tg; hence, this phenomenon has to be accounted for in any crystal nucleation model. [ABSTRACT FROM AUTHOR]

In recent years, with the development of batteries, ceramics, glass and other industries, the demand for lithium has increased rapidly. Due to the rich lithium resources in seawater and salt-lake brine, the question of how to selectively adsorb and separate lithium ions from such brine has attracted the attention and research of many scholars. The Li-ion sieve stands out from other methods thanks to its excellent special adsorption and separation performance. In this paper, mesoporous titanium dioxide and lithium hydroxide were prepared by hydrothermal reaction using bacterial cellulose as a biological template. After calcination at 600 °C, spinel lithium titanium oxide Li2TiO3 was formed. The precursor was eluted with HCl eluent to obtain H2TiO3. The lithium titanate were characterized by IR, SEM and X-ray diffraction. The adsorption properties of H2TiO3 were studied by adsorption pH, adsorption kinetics, adsorption isotherm and competitive adsorption. The results show that H2TiO3 has a single-layer chemical adsorption process, and has a good adsorption effect on lithium ions at pH 11.0, with a maximum adsorption capacity of 35.45 mg g−1. The lithium-ion sieve can selectively adsorb Li+, and its partition coefficient is 2242.548 mL g−1. It can be predicted that the lithium-ion sieve prepared by biological template will have broad application prospects. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the efficacy of different ceramic surface cleaning methods after saliva contamination on the resin bond strength to lithium disilicate ceramics. Materials and Methods: 300 e.max CAD blocks (Ivoclar Vivadent) were polished with 600-grit silicon carbide paper and divided into five groups with or without human saliva contamination and according to the surface treatment performed (n = 10); control: no pretreatment; MP: Monobond Plus; PA+MP: 37% phosphoric acid (PA) followed by MP; HF+MP: 5% hydrofluoric acid (HF) followed by MP; MEP: Monobond Etch & Prime. The specimens were bonded with one of three resin cements: Variolink Esthetic DC (VE), Multilink Automix (MA) and Speed CEM (SC). After 24-h water storage, tensile bond strength (TBS) was measured. The ceramic surfaces after pretreatment were analyzed using x-ray photoelectron spectroscopy (XPS). Results: XPS analysis showed similar elemental distributions between saliva contamination vs no saliva in PA, HF, and MEP. The TBSs were significantly influenced by surface treatments (p < 0.05). HF+MP and MEP showed statistically non-significantly different bond strengths to saliva-contaminated HF+MP and MEP, but were different from MP and saliva-contaminated MP. The TBSs after 24 h were significantly higher in HF+MP and MEP groups with VE. HF+MP and MEP did not show statistically significant differences among any groups with or without saliva contamination. Conclusion: Surface treatments with PA or HF followed by silane or by MEP alone were effective in removing saliva contamination and enhancing the resin bond strength. [ABSTRACT FROM AUTHOR]

The fabrication method of grooves on the surface of alumina and their influence on the surface flashover characteristics of the alumina insulator were studied in this paper. To prepare grooves with a regular surface structure, the UV laser was applied to carve grooves on the surface of alumina ceramic, and dilute hydrochloric acid was used to corrode and remove the residual materials produced in the laser carving process. By adjusting the laser parameters, periodic grooves were prepared on the surface of a cylindrical alumina insulator with a groove depth of 60 µm and a groove width of approximately 50 µm on the laser spinning carving platform. Then, alumina insulators with different periods were prepared, and their vacuum surface flashover voltages were tested on a short pulsed high-voltage test platform. The test results indicated that the flashover voltages of the alumina insulators with laser carved periodic grooves were increased over 200%, and the improvement did not change much with the groove periods. A further study of the groove parameters showed that several grooves fabricated on the cathode end of the insulators were able to improve the flashover voltage of the alumina insulator to the voltage-withstand level of the fully grooved insulators. [ABSTRACT FROM AUTHOR]

This paper summarizes our previous and current studies of using high‐temperature calorimetry to investigate the energetics of reactions of ceramic coating materials (e.g., yttrium disilicate and 7‐wt% yttria‐stabilized zirconia) and their binary oxide components with silicate melts in the CaO–MgO–Al2O3–SiO2 (CMAS) system. Such interactions are found to become stronger (more exothermic) with increasing difference in acid–base character between these materials and the melt. Our results suggest that the reactivity between the coating materials and the melt increases with decreasing thermodynamic stability (less exothermic enthalpy of formation from oxide components) of the coating material. They also suggest that ceramic coating materials made from binary oxides that have less exothermic enthalpies of solution and mixing are less susceptible to CMAS melt corrosion when in contact with an acidic, relatively polymerized, melt rich in SiO2. Thus, we propose that new coating material formulation and CMAS melt corrosion mitigation strategies should be optimized based on the energetic contributions of their binary oxide components. [ABSTRACT FROM AUTHOR]

Purpose: To compare the translucency parameters and masking abilities of different monolithic CAD/CAM ceramics placed on different-colored substructures. Materials and Methods: Square-shaped specimens (12 × 12 × 1.5 mm) were prepared from feldspathic (C), leucite (EMP), lithium disilicate (e.max), zirconiareinforced lithium silicate (VS), resin nanoceramic (LU), polymer-infiltrated ceramic (VE), hybrid nanoceramic (GC), monolithic zirconia (TZI), and composite resin (TC) blocks (n = 10 per material). After mechanical polishing, the translucency parameter (TP) was calculated. Then, each ceramic specimen was measured on eight substructures, and the color difference between ND2 and each substrate was calculated with the CIEDE2000 formula. TP values were analyzed with one-way ANOVA and Games-Howell tests, and the color differences indicating masking ability were analyzed with two-way ANOVA and Tukey HSD tests. Results: The highest TP was observed in TC, followed by LU, EMP, C,GC, e.max, VS, VE, and TZI. The E00 color difference values of TZI, VS, and VE on all abutment colors, except for ND9, were below the acceptable threshold value. Conclusions: All monolithic ceramic materials used in the study masked the ND1 and ND3 substrates. The ND9, representing severely discolored or devitalized preparations, could not be masked by any monolithic CAD/CAM ceramics used in the study. [ABSTRACT FROM AUTHOR]

Lithium-ion capacitors (LICs) are gaining increasing research interest due to their combination of the advantages of lithium-ion batteries and supercapacitors. Carbon–metal oxide/hydroxide hybrid materials show great potential as anode materials for LICs, but their specific capacity still needs further improvement to meet future requirements. In this study, a method of incorporating nickel silicate into carbon–metal oxide/hydroxide hybrid materials is recommended to improve their overall lithium-ion storage performance. This method is easily achieved using silicon oxide-containing bamboo leaf-derived carbon (BLC) as a raw material. A novel nickel hydroxide-nickel silicate-carbon hybrid material (NiSiC) can be obtained via the reaction between BLC and nickel nitrate. When employed as a lithium-ion energy storage electrode material, NiSiC exhibits a significantly higher specific capacity and retained capacity after the cycling test, in contrast to BLC, due to the contribution of nickel-based hybrid materials. Of utmost importance, the nickel silicate component of NiSiC is capable of reducing charge transfer resistance, suppressing electrode volume expansion, and introducing silicon to contribute extra capacity. Consequently, compared to a nickel hydroxide-carbon hybrid material (NiC) lacking the nickel silicate component, NiSiC demonstrates remarkable improvements in rate performance, cycling performance, and specific capacity performance. Owing to the excellent performance of NiSiC, a LIC utilizing NiSiC as the anode material demonstrates excellent lithium storage performance and practical application capabilities. [ABSTRACT FROM AUTHOR]

The current soaring market for lithium-ion batteries (LIBs) in energy storage devices has promoted the recycling and utilization of secondary resources, including retired LIBs. However, current recycling technologies are confronted with numerous deficiencies in balancing extraction efficiency, energy consumption, emissions, and profit. Here, we propose a well-designed thermal oxidation strategy for pyro-process-based Li extraction from spent LiFePO4 (S-LFP), which involves the application of a molten sulfate infiltration–oxidation synergistically controlled reaction occurring at a low temperature (300 °C) and constitutes a one-step preparation with high lithium recovery (>99%) and a high-value iron phosphate (FPO) product. The regenerated LiFePO4 (R-LFP) materials as recycled products exhibit an excellent discharge capacity (136.2 mA h g−1 at 1C) and cycling stability (98.9% capacity retention after 100 cycles). The economic analysis verifies a profit increase of 155% per kilogram and an emission decrease of 216% for this strategy compared with traditional hydrometallurgical processes. The proposed approach is particularly appealing due to its high profit, industrial feasibility, and environmental benefits. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate in vitro the effect of using titanium tetrafluoride as an alternative etchant prior to the silani-zation of the bonding surface on the long-term resin bond strength to lithium disilicate ceramic. Materials and Methods: Disk-shaped specimens made of lithium disilicate ceramic were ground with abrasive paper, then etched with aqueous solutions (2.5% and 5%) of titanium tetrafluoride for 60 s, 120 s and 240 s. Positive control specimens were etched with 5% hydrofluoric acid for 20 s and negative control specimens were not etched. Afterwards, bonding surfaces of all specimens were silanized. Plexiglas tubes filled with a composite resin were bonded to the specimens using an alignment apparatus and a composite luting resin. After storage in 37°C tap water for three days (n = 8) and after storage in 37°C tap water for 150 days interrupted by 5 x 7500 thermal cycles (n = 8), tensile bond strength (TBS) was measured in a universal testing machine at a crosshead speed of 2 mm/min. Results: After artificial aging, all specimens etched with titanium tetrafluoride debonded spontaneously resulting in a TBS of 0 MPa. Therefore, statistical analysis revealed a highly significant difference between the positive control and the test groups after 150 days storage. Conclusion: Etching the bonding surface of lithium disilicate ceramic restorations with hydrofluoric acid is still a "gold standard" and cannot be replaced by titanium tetrafluoride [ABSTRACT FROM AUTHOR]

• The surface morphology can affect the step stress accelerated life test results. • Polished discs showed higher survival probability than roughened discs, however, higher sensibility to the aggressive profile. The present investigation evaluated the step stress accelerated test (SSALT) load profiles on the survival probability of a glass ceramic under two surface conditions (polished or roughened). Suprinity–ZLS blocks (Vita Zhanfabrik) were shaped into cylinders, cut in a sawing machine, and crystalized according to the manufacturer's instructions. 60 discs were obtained (Ø = 12 mm, thickness = 1.2 mm) and randomly assigned into two surface conditions: "p" polished surface (400–1200-grit SiC papers), and "r" roughened surface (200-grit SiC papers). Profilometry was performed in all discs to evaluate average surface roughness prior to flexural fatigue strength testing. 3 discs of each group were submitted to biaxial flexural strength in an universal testing machine (0.5 mm/min) and the mean load to failure (N) was calculated to determine SSALT profiles. 27 specimens per surface condition were assigned into three profiles – Mild (n = 9), Moderate (n = 9), and Aggressive (n = 9), and submitted to the fatigue test (60–320 N, 140,000 cycles at 1.4 Hz). The results were analyzed using the Kaplan-Meier and Wilcoxon tests (5%), 2-way ANOVA and Tukey test (α = 5%). Kaplan-Meier and generalized Wilcoxon showed (P = 0.002) that polished groups showed higher survival probability than roughened condition (P < 0.05). A rough internal surface impacted deleteriously on the fatigue strength and reliability of ZLS ceramic. Both surface conditions were more sensitive to the aggressive profile than the other profiles, even worst for the roughened group. Regardless the load profile, 0% survival probability was observed at 384 MPa for polished condition. While for roughened, aggressive tested specimens did not survived 147 MPa followed by moderate at 312 MPa and mild at 384 MPa. The failure modes showed fracture marks originating from superficial grooves for both surface conditions. Polished specimens are sensitive to the load profile variation, confirming the effect of surface morphology on the fatigue results. [ABSTRACT FROM AUTHOR]

In recent years, mechanical activation technology has been extensively applied as a pretreatment process to increase the leaching efficiency in hydrometallurgical mineral processing. However, studies on its application in the lepidolite bioleaching process are limited. Therefore, the effects of mechanical activation on lithium extraction by an acidophilic iron/sulfur-oxidizing microbial community under different nutrient conditions were evaluated in this study. The solution behavior, phase morphology, and compositional evolution, and microbial community structure succession under eutrophic conditions with exogenous pyrite as the energy substrate and oligotrophic conditions, were investigated. The results revealed that mechanical activation significantly influences the microbial community structure and the interrelationship between microbial activity and mineral phase decomposition and transformation by altering the physical and chemical properties of lepidolite. The best leaching effect was observed in the eutrophic bioleaching groups, followed by the oligotrophic groups at all mechanical activation times. Notably, at a rotation speed of 200 r/min, a material-to-ball mass ratio of 1:20, and an activation time of 150 min, the maximum leaching rates of lithium under eutrophic and oligotrophic conditions were 24.9% and 20.8%, respectively, which were 20.0% and 17.9% higher than those of the nonactivated group. The phase and composition analyses indicated that the dissolution of lithium silicate minerals occurs through a combination of protic acid corrosion, the complexation/electrostatic interactions of extracellular polymeric substances, and the complexation of secondary minerals. These results indicate that the leaching effect is closely related to the pretreatment of mechanical activation, the energy substrates, and the microbial community structure, and this has important reference value for the optimization of the bioleaching process of lepidolite. [ABSTRACT FROM AUTHOR]

The present review provides an up-to-date overview of chairside CAD/CAM materials used in restorative dentistry, focusing on their classification, properties, and clinical applications. If CAD/CAM technology was only an aspiration in the past, a higher proportion of clinics are employing it nowadays. The market is overflowing with biomaterials, and these materials are constantly evolving, making it challenging for practitioners to choose the most appropriate one, especially in correlation with patients' medical diseases. The evolution of CAD/CAM technology has revolutionized dental practice, enabling the efficient fabrication of high-quality restorations in a single appointment. The main categories of chairside CAD/CAM materials include feldspathic ceramics, leucite-reinforced ceramics, lithium disilicate, zirconia, hybrid ceramics, and acrylic resins. The mechanical, physical, and aesthetic properties of these materials are discussed, along with their advantages and limitations for different clinical scenarios. Factors influencing material selection, such as strength, aesthetics, and ease of use, are also assessed. Ultimately, the guiding principle of dentistry is minimally invasive treatment following the particularity of the clinical case to obtain the envisioned result. Correlating all these factors, a simple, up-to-date classification is required to begin an individualized treatment. By synthesizing current evidence, this comprehensive review aims to guide clinicians in selecting appropriate chairside CAD/CAM materials to achieve optimal functional and aesthetic outcomes in restorative procedures. The integration of digital workflows and continued development of novel materials promise to further enhance the capabilities of chairside CAD/CAM systems in modern dental practice. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the color stability of zirconia‐reinforced lithium silicate glass‐ceramic and lithium disilicate reinforced glass‐ceramic, which were prepared with various surface finishing procedures, following 1‐week, 2‐week, 1‐month, and 2‐month storage in various beverages, and after the application of polishing paste. Materials and Methods: Lithium disilicate glass‐ceramic (IPS e.max CAD HT) and zirconia‐reinforced lithium silicate ceramic (Vita Suprinity HT) CAD/CAM blocks were sectioned with a diamond saw (Metkon) under water cooling into 1.5 × 7 × 12 mm dimensions (N = 120). All specimens were polished with silicon carbide paper (600‐, 800‐, and 1200‐grit) under water for 120 seconds. The specimens were prepared using 3 surface finishing procedures: glaze, mechanical polishing, and external staining and glaze in accordance with manufacturers' instructions. Then, each group was divided into 2 storage subgroups, black tea and coffee (n = 10/group). Color values were measured in CIELAB color space with dental spectrophotometer (VITA Easyshade) at the initial stage, and following 1‐week, 2‐week, 1‐month, 2‐month storage, and after fine‐grit polishing paste application (Proxyt). Color changes (ΔE) were calculated and statistically analyzed using ANOVA followed by Bonferroni corrected post‐hoc tests using Number Cruncher Statistical System 2007 (α < 0.05). Results: For lithium disilicate glass‐ceramic, glaze procedure showed statistically lower color change values than mechanical polishing and external staining and glaze surface finishing groups (p < 0.05) following storage in both beverages, whereas for zirconia‐reinforced lithium silicate ceramic, glaze procedure showed statistically lower color change values than mechanical polishing, but statistically insignificant values with respect to external staining and glaze group, following storage in both beverages. Lithium disilicate glass‐ceramic groups showed statistically lower or statistically insignificant color change values with respect to zirconia‐reinforced lithium silicate ceramic groups, except for the external staining and glaze surface finishing group in coffee. Significantly lower discoloration values were obtained following polishing paste application, with respect to 2‐month storage in beverages (p < 0.05). Conclusion: Glazing alone led to more color stability with respect to mechanical polishing and external staining and glaze for zirconia‐reinforced lithium silicate and lithium disilicate glass‐ceramic. Lithium disilicate glass‐ceramic showed higher color stability compared to zirconia‐reinforced lithium silicate ceramic. Polishing paste resulted in a decrease in discoloration to clinically acceptable values. [ABSTRACT FROM AUTHOR]

Sodium potassium niobate (KNN) based piezoceramics added with different amount of ZnO were prepared by ceramic method using high energy ball milling. The samples prepared have compositional formula Na0. 47K0.47Li0.06NbO3 + (x) ZnO (x = 0 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, and 2 wt%) and sintered at 1000 °C for 2 h. The crystalline phase, microstructure, electrical properties of the samples such as dielectric constant, dielectric loss as well as a.c conductivity of the prepared samples were investigated. It was observed that the addition of ZnO to Na0.47K0.47Li0.06NbO3 ceramics enhanced the density, electrical properties as well as piezoelectric property. X-ray diffraction (XRD) confirmed a perovskite tetragonal phase in all the samples. The X-ray density was found increased and the maximum value was obtained at 1 wt% ZnO addition Polarization–electric field (P-E) loop for the samples was traced and the remnant polarization value is found to be highest at 1 wt% ZnO addition with maximum piezoelectric constant, d33 ~ 86 pC/N amongst all the samples under study. The results of the various measurements were explained in this paper. [ABSTRACT FROM AUTHOR]

The starting materials and temperature for the preparation of Li3NaSiO4 powder, which has attracted attention as a CO2 absorbent, were optimized in this study. Mixtures of Li2CO3, Na2CO3, and SiO2 as well as Li4SiO4, Li2SiO3, and Na2CO3 were subjected to thermogravimetry-differential thermal analysis (TG-DTA) to elucidate their reaction mechanisms. The phase, morphology, specific surface area, and CO2 absorption characteristics of the powder specimens that were obtained by heating the two mixtures were examined by X-ray diffraction (XRD), secondary electron microscopy (SEM), N2 adsorption isotherm and isothermal TG-DTA. Melted LiNaCO3 was generated via the heat treatment of the Li2CO3, Na2CO3, and SiO2 powder mixture, yielding a low-purity bulk specimen with inhomogeneous particle size. However, the use of the Li4SiO4, Li2SiO3, and Na2CO3 mixture as a starting material ensured that no liquid phase was generated during heat treatment and successfully yielded Li3NaSiO4 powder which was purer than the product derived from the Li2CO3/Na2CO3/SiO2 mixture, presumably because of the lower volatility of Li and Na in the solid phase than that in the liquid phase of LiNaCO3. The Li3NaSiO4 powder derived from Li4SiO4, Li2SiO3, and Na2CO3 showed a slightly larger surface area with homogeneous particle size and almost identical CO2 absorption kinetics compared to those of the product obtained from Li2CO3, Na2CO3, and SiO2, in addition to absorbing a higher amount of CO2 owing to its higher purity. [ABSTRACT FROM AUTHOR]

Surface modification is an effective technique to improve the electrochemical performance of electrode materials. However, although carbon coating is cheap and applicable, it is unsuitable for some high-valence metal oxide compounds due to the reduction of carbon. In this work, manganese tellurium molybdate, MnTeMoO6, was developed utilizing lithium silicate Li2SiO3 coating as an extra solid-state electrolyte layer, and its electrochemical performance was investigated in detail. Importantly, the dQ/dV curve and AC impedance test under variable temperatures were further analyzed to demonstrate the relationship between changes in the discharge platform during the discharge process of the electrode material. The activation energy Ea of the interfacial lithium-ion transfer at the electrode interface was evaluated preliminarily. It was confirmed that the MnTeMoO6@Li2SiO3 composites exhibited enhanced electrochemical performance with lower activation energy than that of the bare compound. [ABSTRACT FROM AUTHOR]

ZrO2 is commonly incorporated into glass-ceramic dental post to enhance its radiopacity, mechanical strength, and chemical durability. Experience has shown that the crystallization of tetragonal zirconia in glass will have a more significant effect on the mechanical properties of the resulted sample. Stabilizing oxides are often added to achieve optimal properties in zirconia and enhance its structural and mechanical qualities. In this research, to stabilize the tetragonal phase of zirconia, MgO and CeO2 were added gradually to the glass-ceramic composition of the Li2O-SiO2- ZrO2 system, and the desired dental core was synthesized through the sintering process. The behavior of sintering and crystallization of basic and optimized glass was investigated using HSM (hot stage microscope) and DTA (differential thermal analyses), respectively. The results showed that the optimal sintering temperature, heat press, and heat treatment were 730°C, 900°C, and 825°C, respectively. To determine the crystallization behavior of the prepared samples, X-ray diffraction, and microstructure images were used. The results also showed that Li2ZrSi6O15 crystallizes as the main crystalline phase at a temperature of 825°C in the base sample and the sample containing ceria. Also, due to the early formation of MgSiO3 crystals, magnesia prevents sintering and formation of the Li2ZrSi6O15 and stability of the tetragonal zirconia phase. In the sample containing ceria, during crystallization of ZrO2 ceria entered into its crystal structure, leading to the stability of the tetragonal zirconia phase up to room temperature. [ABSTRACT FROM AUTHOR]

This study evaluated whether airborne-particle abrasion could be an alternative to hydrofluoric acid etching as a pretreatment for the adhesive bonding of silicate ceramic restorations. Feldspar (FEL; n = 100), lithium silicate (LiSi; n = 100), and zirconia (ZrO2; (n = 80) substrates were CAD/CAM-fabricated and airborne-particle-abraded with Al2O3 (25 µm or 50 µm of mean particle size) at pressures of 0.05 or 0.1 MPa. The controls included FEL (60 s) and LiSi (20 s) etched with hydrofluoric acid. The surface free energy (SFE) and roughness (Ra) were measured. For the tensile bond strength (TBS), surfaces were conditioned using a primer (Monobond Plus) and luted to a resin composite (Variolink Esthetic). TBS was assessed initially (24 h, 37 °C water storage) and after thermocycling (5/55 °C, 10,000×). Statistical analysis (SPSS, V29) was performed using a one-way ANOVA, post hoc Scheffé, and a two-group t-test (p = 0.05). Abrasion with 50 µm and 0.1 MPa induced the highest Ra values across the materials (62.5 ± 3.88 µm). ZrO2 exhibited a higher TBS (35.4–49.5 MPa) than FEL and LiSi. For aged LiSi, the specimens treated at 0.1 MPa showed a higher TBS (18.7 ± 9.0 MPa) than those treated at 0.05 MPa, regardless of the particle size. The etched and aged FEL showed a higher SFE but a lower TBS compared to abrasion. Al2O3 particle abrasion (25 or 50 µm at 0.1 MPa) may replace etching for silicate-based ceramics, while 50 µm is recommended for ZrO2 at either pressure. [ABSTRACT FROM AUTHOR]

The aim of this investigation was to evaluate the effect of etching protocols on bond strength, surface roughness, and mechanical properties of a zirconia-reinforced lithium silicate (ZLS) CAD/CAM-ceramic. In total, 100 bars (ISO 6872), 75 plaques, and 25 cubes were cut from ZLS blocks(Vita Suprinity®). The surfaces were standardized, crystallized and divided into five groups: 1. control (no/treatment-C), 2. 5%-Hydrofluoric-acid (HF)/20 s (HF5%20s), 3.HF5%60s, 4.HF10%20s, and 5.HF10%60s. Flexural strength (FS) (three-point bending test, 1 mm/min), roughness (Pa), and micro-shear bond-strength (µSBS) tests were performed. The data were statistically analyzed with one-way ANOVA, Tukey's test (p ˂ 0.05) and Weibull (FS data). C showed higher Pa (1.176 ± 0.370 µm) than HF10%60s (0.627 ± 0.236 µm) and all other groups. Groups C and 20 s showed the most irregular surface patterns. The FS results were not influenced by etching protocols, while the Weibull modulus was, with the 5%HF groups being the most reliable (m: 5.63/6.70), while C and HF10%60s (m: 2.78/2.73) were the least reliable. All fractures originated from surface defects on the treated side of specimens. The 5%HF groups showed higher µSBS (20 s: 21.35 ± 4.70 MPa; 60 s: 23.50 ± 4.27 MPa) than the 10%HF groups (20 s: 14.51 ± 2.47 MPa; 60 s: 16.54 ± 3.12 MPa) and C (6.46 ± 2.71 MPa). The most prevalent failure pattern was "mixed" for etched groups, and "adhesive" for C. Etching protocols affect the evaluated properties by roughening materials' surface and, in some cases, regularizing surface defects. The best overall outcomes were achieved when applying 5%HF. [ABSTRACT FROM AUTHOR]

When partial and/or non-retentive preparation, such as those for occlusal veneers, is indicated, a proper and stable adhesion is essential. Therefore, the aim of this in vitro study was to evaluate the effect of loss of adhesion in different regions of the bonding interface on the fatigue behavior of simplified lithium disilicate restorations. For this, lithium disilicate (IPS e.max CAD) discs (1 mm thick and Ø = 10 mm) were fabricated, polished with #400-, #600-, #1200-grit silicon carbide (SiC) papers, and crystallized. As substrate, fiber-reinforced resin epoxy discs (2.5 mm thick and Ø = 10 mm) were fabricated and polished with #600-grit SiC paper. The ceramic bonding surface was treated with 5% hydrofluoric acid and a silane-containing primer (Monobond N), while the substrate was etched with 10% hydrofluoric acid followed by the application of the bonding system primers (Primer A + B). A lacquer (nail polish) was used to simulate the loss of adhesion in specific areas according to the study design to compose the testing groups: bonded (control; did not received nail polish application); – non-bonded (loss of adhesion in the whole specimen area); – margin (loss of adhesion in the ceramic margin); – center (loss of adhesion in the ceramic central area). The adhesive area of partially bonded groups was 50% of the adhesive surface. Then, the discs (n = 12) were bonded to the respective substrate using a resin cement (Multilink N), light-cured, water-stored for 90 days, and subjected to thermocycling (25,000 cycles, 5° to 55 °C) before testing. A cyclic fatigue test was run (20 Hz, initial load of 200 N for 5000 cycles, 50 N step size for 10,000 cycles each until specimen failure), and the fatigue failure load and number of cycles for failure were recorded. As complementary analysis, finite element analysis (FEA) and scanning electron microscopy analysis were performed. Kaplan-Meier log-rank (Mantel-Cox) was conducted for survival analysis. The results showed that as the loss of adhesion reaches the central area, the worse is the fatigue behavior and the higher is the stress peak concentration in the ceramic bonding surface. The bonded specimens presented better fatigue behavior and stress distribution compared to the others. In conclusion in a non-retentive preparation situation, proper adhesion is a must for the restoration fatigue behavior even after aging; while the loss of adhesion reaches central areas the mechanical functioning is compromised. • The fully bonded scenario promotes better fatigue behavior and stress distribution. • The loss of adhesion in restoration's central areas compromises the mechanical performance. • Stress peaks are higher in adhesion-loss scenarios, regardless of the debonded region. [ABSTRACT FROM AUTHOR]

Lithium iron silicate has caught tremendous attentions as an appealing cathode for future lithium-ion batteries due to high capacity, low cost, and environmental friendliness, and its drawback of extremely low conductivity can be overcome efficiently through nanoarchitecture building. However, the construction of nanostructures always involves with expensive surfactants and complicated synthetic processes, which restrict these methods from large-scale production. In this paper, we develop a simple synthetic route to prepare hierarchical porous Li2FeSiO4/C. XRD, SEM, TEM, Raman, and N2 adsorption-desorption are employed to investigate its physical properties. Electrochemical tests reveal that the composite delivers a high specific capacity of 243.5 mAh g−1, superior rate capability, and excellent cycling performance with capacity retention of 95.2% after 200 cycles. The excellent electrochemical performance should be attributed to the unique structure in which hierarchical pores provides fast transport channels for lithium ions and interconnected carbon coating builds up conductive networks to enhance the conductivity of Li2FeSiO4. In addition, electrochemical impedance spectroscopy, ex situ SEM, and TEM are conducted to demonstrate its structural stability upon long-term cycling. In addition, the route described in this work is facile, cheap, and easily scaled-up, which allows for extension to the fabrication of other energy storage materials. [ABSTRACT FROM AUTHOR]

Aim: Color matching of the restoration to the adjacent teeth can be difficult due to the translucency of the ceramic and the visual exposure of the polymerized resin cement through the ceramic material. The aim of this study was to identify color differences between try-in pastes and the corresponding luting resin composites. Materials and methods: The materials tested were Variolink Veneer, Variolink Try-In, Variolink Esthetic LC, and Variolink Esthetic Try-In. Blocks of IPS e.max CAD were bisected along the vertical axis, producing specimens of different thicknesses. The surfaces to be evaluated were finely polished with a metallographic machine using 6000 grit SiC paper. The IPS e.max CAD specimens cemented with resin cement or with the try-in pastes were superimposed on a resin composite specimen reproducing the tooth structure. Evaluation of the color differences between the try-in pastes and polymerized cements of the same shade was performed with a spectrophotometer and a visual evaluation by three observers. Results: The measurements showed that for shades of Variolink Veneer and Variolink Esthetic LC resin cements and the corresponding try-in pastes there were significant color differences ΔE > 2.23). Among the groups of different thicknesses, specimens of 0.5-mm thickness exhibited the highest ΔE values, while the specimens of 2-mm thickness exhibited the lowest. Conclusions: The present study suggests that dentists should not rely on try-in pastes for the final color evaluation because they do not perfectly match the color shade of the cement used for the final luting of ceramic restorations. The originality of this study was the interpretation of color differences utilizing both a scientific spectrophotometer and visual observation. (Int J Esthet Dent 2018; 13:98-109) [ABSTRACT FROM AUTHOR]

Recently there has been increasing interest to develop lithium-containing films as solid-state electrolytes or surface coatings for lithium-ion batteries (LIBs) and related systems. In this study, we for the first time investigated the thin film growth of lithium zirconium oxides (LixZryO or LZOs) through combining two individual atomic layer deposition (ALD) processes of ZrO2 and LiOH, i.e., sub-ALD of ZrO2 and LiOH. We revealed that the hygroscopic nature of the LiOH component has a big impact on the growth of LZOs. We found that an increased temperature to 225 °C was more effective than an elongated purge to mitigate the adverse effects of physisorbed H2O. We further discovered that, during the resultant LZO super-ALD processes, the growth of sub-ALD LiOH has been promoted while the growth of sub-ALD ZrO2 has been inhibited. In this study, a suite of instruments has been applied to characterize the LZO super-ALD processes and the resultant LZO films, including in situ quartz crystal microbalance (QCM), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), atomic force microscopy (AFM), synchrotron-based X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Furthermore, we applied the resulting LZO films over LiNi0.6Mn0.2Co0.2O2 (NMC622) cathodes in LIBs and demonstrated that the LZO coating films could evidently improve the lithium-ion insertion and extraction rates of the NMC622 electrodes up to 3.4 and 2.6 times, respectively. The LZO-coated NMC622 cathodes exhibited much better performance than the uncoated NMC622 ones. [ABSTRACT FROM AUTHOR]

Pursuing improved electrode materials is essential for addressing the challenges associated with large-scale Li-ion battery applications. Specifically, silicon oxide (SiOx) has emerged as a promising alternative to graphite anodes, despite issues related to volume expansion and rapid capacity degradation. In this study, we synthesized carbon-coated SiOx using diatom biomass derived from artificially cultured diatoms. However, the inherent carbon content from diatoms poses a significant challenge for the electrochemical performance of diatom-based anodes in large-scale applications. Subsequently, we conducted further research and demonstrated excellent performance with a carbon content of 33 wt.% as anodes. Additionally, real-time characterization of the carbonization process was achieved using thermogravimetry coupled with infrared spectroscopy and gas chromatography mass spectrometry (TG-FTIR-GCMS), revealing the emission of CO and C3O2 during carbonization. Furthermore, electrochemical tests of the processed diatom and carbon (PD@C) anode exhibited outstanding rate capability (~500 mAh g−1 at 2 A g−1), high initial Coulomb efficiency (76.95%), and a DLi+ diffusion rate of 1.03 × 10−12 cm2 s−1. Moreover, structural characterization techniques such as HRTEM-SAED were employed, along with DFT calculations, to demonstrate that the lithium storage process involves not only reversible transport in Li2Si2O5 and Li22Si5, but also physical adsorption between the PD and C layers. Exploring the integration of diatom frustules with the intrinsic carbon content in the fabrication of battery anodes may contribute to a deeper understanding of the mechanisms behind their successful application. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study was to evaluate the differences in lightness (ΔL), chroma (ΔC), and hue (ΔH) of zirconia-reinforced glass ceramic (ZLS) samples of various thicknesses, which underwent different surface finishing procedures, after aging and staining solutions. Methodology: Sixty samples of ZLS blocks were produced in two different thicknesses (12x14x1 mm, n=30; 12x14x1.5 mm, n=30), and different surface treatments were applied to them (mechanical polishing or glaze; n=15). After polishing and glazing, all samples were cleaned using an ultrasonic cleaner for 10 minutes. Color measurements were taken using a spectrophotometer before and after autoclave aging and immersion in staining solutions (tea, coffee, and coke), and color values were calculated using the CIEDE2000 formula. The Kolmogorov-Smirnov, Shapiro, three-way ANOVA, and Tukey HSD tests were used for statistical evaluation. Results: The common effects of surface finishing treatment, staining solution, and thickness interaction on ΔL and ΔC values were found to be statistically significant (p<0.05), while the common effect on ΔH values was not found to be significant (p>0.05). The ΔL and ΔH values (5.06 ± 1.60 and 2.95 ± 0.61, respectively) were the highest in the groups with 1 mm thickness, mechanical polishing, and immersion in tea solution. The highest ΔC value (4.21 ± 0.35) was noted for the group with 1 mm thickness, mechanical polishing, and immersion in cola solution. Conclusion: Differences in material thickness and the staining solution affected the lightness, hue, and chroma of the ZLS samples. The difference in the surface finishing procedure affected the hue and chroma but not the lightness. [ABSTRACT FROM AUTHOR]

Silicon oxide‐coated lithium aluminum layered double hydroxide (LixAl2‐LDH@SiO2) nanocrystals (NCs) are investigated to selectively separate lithium cations in aqueous lithium resources. We directly synthesized LixAl2‐LDH NC arrays by oxidation of aluminum foil substrate under a urea and lithium solution. Various lithium salts, including Cl−, CO32−, NO3−, and SO42−, were applied in aqueous solution to confirm the anion effect on the captured and released lithium quantity of the LixAl2‐LDH NCs. In a 5% solution of sulfate ions mix with lithium chloride, the LixAl2‐LDH NCs separated a larger quantity of lithium than in other anion conditions. To enhance regeneration stability and lithium selectivity, thin layers of SiO2 were coated onto the LixAl2‐LDH nanostructure arrays for inhibition of nanostructure destruction after desorption of lithium cations in hot water. The LixAl2‐LDH@SiO2 nanostructures showed enhanced properties for lithium adsorption, including increase of stable regeneration cycles from three to five cycles, and they showed high lithium selectivity in the Mg2+, Na+, and K+ cation mixed aqueous resource. Our nanostructured LDH lithium adsorbents would provide a facile and efficient application for cost‐efficient and large‐scale lithium production. [ABSTRACT FROM AUTHOR]

(1) Background: The presence of various dental ceramic materials with different chemical compositions complicates clinicians' decision making, especially in cases with a highly acidic environment appearing in patients suffering from gastroesophageal reflux disease or other eating disorders. Thermal alterations in the oral cavity can also affect surface structure and roughness, resulting in variations in both degradation mechanisms and/or bacteria adhesion. The aim of the present in vitro study was to evaluate the effect of thermal cycling and exposure to simulated gastric acid on the surface roughness of different ceramics; (2) Methods: Five groups of different ceramics were utilized, and twenty specimens were fabricated for each group. Specimens were either thermocycled for 10,000 cycles in distilled water or immersed in simulated gastric acid for 91 h. The evaluation of surface roughness was performed with optical profilometry, while scanning electron microscopy, X-ray diffraction analysis and inductively coupled plasma atomic emission spectroscopy were also performed; (4) Conclusions: Based on the combination of the surface roughness profile and structural integrity, zirconia specimens presented the smallest changes after immersion in simulated gastric acid followed by lithium disilicate materials. Zirconia-reinforced lithium silicate ceramic presented the most notable changes in microstructure and roughness after both treatments. [ABSTRACT FROM AUTHOR]

To address the problem of insufficient temperature and salt resistance of existing polymer viscosity enhancers, we designed an organic–inorganic hybrid composite as a viscosity enhancer for water-based drilling fluids, named LAZ, and it was prepared by combining a water-soluble monomer and lithium magnesium silicate (LMS) using an intercalation polymerization method. The composite LAZ was characterized using Fourier transform infrared spectroscopy, transformed target X-ray diffractometry, scanning electron microscopy, and thermogravimetric analysis. The rheological properties of the composite LAZ were evaluated. The composite LAZ was used as a water-based drilling fluid viscosity enhancer, and the temperature and salt resistance of the drilling fluid were evaluated. The results showed that the composite LAZ presented a complex reticulation structure in an aqueous solution. This reticulation structure intertwined with each other exhibited viscosity-enhancing properties, which can enhance the suspension properties of water-based drilling fluids. The aqueous solution of the composite LAZ has shear dilution properties. As shear rate increases, shear stress becomes larger. The yield stress value of the aqueous solution increases as the composite LAZ's concentration increases. The aqueous solution of the composite LAZ exhibits strong elastic characteristics with weak gel properties. The addition of the composite LAZ to 4% sodium bentonite-based slurry significantly increased the apparent viscosity and dynamic shear of the drilling fluid. The drilling fluids containing the composite LAZ had good temperature resistance at 150 °C and below. The rheological properties of brine drilling fluids containing the composite LAZ changed slightly before and after high-temperature aging at 150 °C. [ABSTRACT FROM AUTHOR]

Abstract: In the context of the ionic transport in glasses, the concept of conduction channels (or pathways) has proved to be useful to rationalize both experimental and computational results. While the concept of a transport “channel” is well defined for crystalline solid conductors, for the case of glasses this concept mainly refers to a finite region of the sample (at least in the diffusive time scale) in which mobile ions have a convenient environment to perform the electrical transport. In the previous work, we present an alternative way to put into evidence the existence of such regions in the diffusion time scale during a molecular dynamics experiment. In fact in that work [1] we use the so-called isoconfigurational ensemble method (ICEM) and the associated concept of particle propensity, both recently introduced by Harrowell and co-workers [2]. Then the notion of particle propensity to movement—immerse in the ICEM—was employed to find the existence of regions which are dynamically more active for the moving particles: the conduction channels. In the present paper we provide more computational evidence to support our alternative way to make evident the existence of channels that we presented in [1]: we show in this paper that our procedure is exactly equivalent to the approach previously adopted by other authors in the literature. This coincidence between the two searching strategies allow us to add more information about the nature of the channels. In fact, we can state now for the first time that the existence of the channels is defined at the very beginning of the dynamics and they remain almost unchanged even in the diffusive (nanosecond) scale. Besides, it was shown that a channel is a region of a sample which is also highly correlated dynamically during the trajectory of the moving ions. [Copyright &y& Elsevier]

This paper reports on the responses of pre-crystallized and crystallized zirconia-containing lithium silicate glass ceramics (ZLS) to diamond machining in simulated dental milling and adjusting processes. Machining mechanics, tool wear and tribological characteristics, and surface and subsurface damage were investigated. Machining forces and coefficients of friction were measured using a force sensor and high-speed data acquisition system. Diamond tool wear and debris adhesion, and machining-induced surface and subsurface damage were examined using field emission scanning electron microscopy. The results show that both tangential and normal forces of crystallized ZLS were significantly higher than those of pre-crystallized ZLS (p < 0.05) while these forces for both materials significantly increased with the material removal rate (p < 0.05). Coefficients of friction in machining of crystallized ZLS were significantly higher than those in machining of pre-crystallized ZLS. In spite of the minimum wear of applied diamond tools in machining both materials, more crystallized ZLS debris adhesion on tool surfaces was observed. The principal removal mechanisms in machining of both materials were primary fracture and minor plastic deformation of pre-crystallized and crystallized ZLS. However, there was more severe fracture in machining of pre-crystallized ZLS than in machining of crystallized ZLS. Although machining-induced subsurface edge chipping damage in both materials remarkably increased with the feed rate (p < 0.05), such damage was significantly severer in pre-crystallized ZLS than in crystallized ZLS (p < 0.05). These microstructure-property-processing relations provide practical guidance of process selection for high-quality fabrication of ZLS materials. [ABSTRACT FROM AUTHOR]

In unsupervised learning (UL)-oriented spiking neural network (SNN) designs, the initial conductance variation of the synapses is usually necessary, with which temporally differentiated responses of the output neurons can be achieved given the same input patterns, in order to implement the important lateral inhibition function. We take a lithium silicate memristor as an example and demonstrate through a motion-style recognition task that, without regulating the initial conductance variation of memristor synapses, several types of errors will occur: too large conductance variance leads to the deactivation of some output neurons and the incomplete learning of the motion routes, while too small variance causes duplicated learnings of the same pattern. By tuning the memristor conductance variance through the forming voltages, it is found that the UL capacity can be optimized, indicating a promising approach to enhance the UL performance of a memristor-based SNN. [ABSTRACT FROM AUTHOR]

Abstract This paper reports on a cyclic nanoindentation approach of a pre-crystallized zirconia-reinforced lithium silicate glass ceramic (ZLS) to understand its material behavior associated with its machinability in dental CAD/CAM diamond abrasive milling. The material response to the cyclic nanoindentation using a Berkovich diamond tip was quantitatively determined in terms of the indentation contact hardness, elastic modulus, elasticity and plasticity for each loading cycle at peak loads of 2.5–10 mN. The cyclic load-displacement curves at different load levels indicate discrete discontinuities and hysteresis loops, which might have arisen from viscoelasticity behavior. Material properties degraded with an increasing number of loading cycles due to the mechanical softening which may facilitate machining in dental CAD/CAM milling. Elastic and plastic displacements and indentation energies revealed the pre-crystallized ZLS experiences predominantly elastic deformation and thus has a high capacity to retain its structure and shape. Furthermore, elastic energy dominated cyclic loading led to pseudoelasticity due to plastic strain accumulation. In situ scanning probe microscopy (SPM) images of cyclic indentation imprints reveal the fracture-free plastic deformation of the pre-crystallized ZLS under cyclic nanoindentation conditions. The outcomes of this study provide the mechanics model of diamond milling of the pre-crystallized ZLS due to the cyclic loading nature of dental CAD/CAM abrasive processing. [ABSTRACT FROM AUTHOR]

Lithium is a significant energy metal. This study focuses on the extraction of lithium from lithium-bearing clay minerals utilizing calcination combined with oxalic acid leaching. The relevant important parameters, leaching kinetics analysis, and the lithium extraction mechanism were deeply investigated. The results demonstrate that a high lithium recovery of 91.35% could be achieved under the optimal conditions of calcination temperature of 600 °C, calcination time of 60 min, leaching temperature of 80 °C, leaching time of 180 min, oxalic acid concentration of 1.2 M, and liquid-to-solid ratio of 8:1. According to the shrinkage core model, the leaching kinetics of lithium using oxalic acid followed a chemical reaction-controlled process. XRD, TG, and SEM analysis showed that the kaolinite, boehmite, and diaspore phases in raw ore transformed into corundum, quartz, and muscovite phase in calcination products when the calcination temperature was higher than 600 °C. Moreover, the expansion of the interlayer spacing of minerals during the calcination process could promote the lithium release. During the leaching process, lithium present in the layered silicates was efficiently recovered through ion exchange with the dissociated H+ from oxalic acid. This study could provide a promising guide for lithium extraction from lithium-bearing clay minerals. [ABSTRACT FROM AUTHOR]

Hydrofluoric acid (HF) is commonly used as an etchant for the pretreatment of dental computer-aided design/computer-aided manufacturing (CAD-CAM) materials, such as glass-ceramics and resin composites. Despite its effectiveness, the harmful and hazardous nature of HF has raised significant safety concerns. In contrast, ammonium fluoride (AF) is known for its relatively low toxicity but has limited etching capability. This study explored the potential of ammonium hydrogen sulfate (AHS), a low-toxicity and weak acid, to enhance the etching ability of aqueous AF solutions for the bonding pretreatment of CAD-CAM materials. This study investigated five types of aesthetic CAD-CAM materials: lithium disilicate glass, feldspathic porcelain, polymer-infiltrated ceramic networks, resin composites, and zirconia. Seven experimental etchants were prepared by varying the amount of AHS added to aqueous AF solutions, with each etchant used to etch the surfaces of the respective CAD-CAM materials. The treated surfaces were analyzed using scanning electron microscopy and confocal laser scanning microscopy. Additionally, the shear bond strength (SBS) of the CAD-CAM materials treated with a luting agent (resin cement) was evaluated. The results indicated that the AF1/AHS3 (weight ratio AF:AHS = 1:3) etchant had the most substantial etching effect on the surfaces of silica-containing materials (lithium disilicate glass, feldspathic porcelain, polymer-infiltrated ceramic networks, and resin composites) but not on zirconia. The SBS of the materials treated with the AF1/AHS3 etchant was comparable to that of the commercial HF etchant. Hence, an AF/AHS mixed solution could effectively etch silica-containing CAD-CAM materials, thereby enhancing their bonding capabilities. [ABSTRACT FROM AUTHOR]

Extracting lithium from spodumene by sulfuric acid roasting is the largest commercialized way at present, which not only consumes a large amount of energy but also produces massive waste residue that will cause environmental problems. In this work, a new process for extracting lithium by directly decomposing α‐spodumene through alkali calcination is designed. The reaction of α‐spodumene with Na2CO3 at 750 °C for 2 h can decompose it and form nepheline and lithium silicate/sodium silicate. The nepheline and soluble lithium silicate/sodium silicate are separated by water leaching, and 93.9 % of lithium can be leached under optimal conditions. In addition, the synthesis of nano‐kaolinite is investigated with nitric acid solutions. Conversions of 98.7 % were obtained with 0.4 M nitric acid at 250 °C and an L/S ratio of 17.5 L/kg. The water leachate can precipitate Li2CO3 with a purity of 99.0 % by CO2 after desilicated by CaO. The final yields of Li2CO3 and kaolinite relative to the Li and Si content of the starting minerals are 91.4 % and 48.5 %, respectively. This new method achieves the full utilization of spodumene with lower energy consumption and demonstrates great potential for industrial applications. [ABSTRACT FROM AUTHOR]

This paper assesses the impact of preheating of adhesive cement on the fracture resistance of lithium disilicate and zirconia restorations. Methods: A total of 80 human maxillary premolar teeth were assigned into 8 groups (n = 10) according to material type (either lithium disilicate or zirconia) and type of resin cement (either LinkForce or Panavia SA) with preheating temperature at 54 °C or at room temperature (25 °C). Teeth were prepared and restored with either lithium disilicate or zirconia restorations. After cementation, specimens were thermal cycled (10,000 cycles, 5 °C/55 °C), then load cycled for 240,000 cycles (50 N). Each specimen was statically loaded until fracture and the load (N) at fracture was recorded, then the failure mode was detected. Statistical analysis of data was performed (p ≤ 0.05). Results: There was no significant difference (p = 0.978) in fracture mean values between LinkForce and Panavia SA. Statistically significant difference (p = 0.001) was revealed between fracture resistance of lithium disilicate restorations cemented with LinkForce at 25 °C and at 54 °C; however there was no significant difference (p = 0.92) between the fracture resistance of lithium disilicate restorations cemented with Panavia SA used at 25 °C and at 54 °C. Regarding the interaction between ceramic material, cement type, and cement preheating, there was no significant effect (p > 0.05) in fracture resistance. The cement type does not influence the fracture resistance of ceramic restorations. Preheating of resin cement has negatively influenced the fracture resistance of all tested groups, except for lithium disilicate cemented using LinkForce cement. [ABSTRACT FROM AUTHOR]

Lithium silicates have received noteworthy interest as a class of materials with significant potential in lithium ion batteries, ionic conductors, optical waveguides and sensors, and efficient sorbents for CO2 capture. Herein we report the optical properties, electronic structures, and surface characteristics of two distinct lithium silicate crystal phases using first-principles hybrid density functional theory (DFT) calculations and in-depth experimental characterization studies. Orthorhombic Li2SiO3 (space group Cmc21) and Li2Si2O5 (space group Ccc2) nanoparticles (NPs) passivated with alkylamine and alkane surface functionalities were produced by reacting SiI4 with n-butyllithium in the presence of 1,2-hexadecanediol. The as-synthesized nanostructures exhibit poor crystallinity, which upon annealing at 600 °C adopt phase-pure orthorhombic crystal structures with spherical (Li2SiO3), polyhedral or rod-shaped (Li2Si2O5) morphologies. The surface analysis of Li2SiO3 and Li2Si2O5 NPs reveals distinct chemical states for Li+, Sin+, and On−, consistent with their stoichiometry and higher binding energies for constituent elements in Li2Si2O5 NPs. Hybrid functional calculations predict indirect and direct energy gaps of 7.79 and 7.80 eV for Li2SiO3 and Li2Si2O5, respectively, signifying the insulating nature of extended solids. Nonetheless, the as-synthesized Li2SiO3 and Li2Si2O5 NPs exhibit high intensity visible photoluminescence (quantum yields = 10–30%) with nanosecond timescale decays at 15 K and 295 K, which we attribute to radiative recombination from surface/interface traps. The facile colloidal synthesis provides control over the crystal structure and composition of nanostructured lithium silicates, which will potentially widen their applications as visible to IR transparent optical materials, chromophores, waveguides, sensors, and high surface area CO2 sorbents. [ABSTRACT FROM AUTHOR]

A novel, facile, one-step hydrothermal method for the direct growth of lithium magnesium silicate (hectorite) nanotubes on a silicate glass slide has been developed. Due to the surface tension induced by lattice defects, the initially synthesized two-dimensional hectorite nanosheets were spontaneously cured in situ thereby forming nanotubes with external diameters of around 100–200 nm and lengths of several micrometers on a glass slide substrate under hydrothermal conditions. This is totally different from those prepared from the conventional hydrothermal method that employs various water colloidal materials as the silicate source. The characterization results suggest that the use of a bulk substrate glass slide and alkaline conditions are the two key points for obtaining tube-like synthetic hectorites with a high intensity of surface negative charges. The calculated band gap of hectorite nanotubes is 3.16 eV by diffuse reflection spectroscopy (DRS), which is much narrower than that of hectorites sheets. Furthermore, under the same measurement conditions, the ionic conductivity of synthetic hectorites increases with its curling up degree, which is mainly attributed to the intensified concentration and accelerated mobility of carriers, as supported by the zeta potential results. [ABSTRACT FROM AUTHOR]

This paper reports on the mechanical behavior of pre-crystallized CAD/CAM zirconia-reinforced lithium silicate glass ceramic (ZLS) using nanoindentation with a Berkovich diamond tip and in situ scanning probe microscopy (SPM). The indentation contact hardness, the elastic modulus, and the elasticity and plasticity of the material were determined using the Oliver-Pharr method, the Sakai model and the Meyer's law at peak loads of 2.5–10 mN and a loading rate of 0.5 mN/s. The load-displacement curves at all applied loads indicate that ZLS deformed plastically without fracture. The discrete discontinuities in the load-displacement curves might have arisen from the shear plane activation for plastic deformation. The measured hardness and elastic modulus were load-independent (ANOVA, p  > 0.05), in ranges of 8.17 ± 1.23 GPa to 9.86 ± 1.24 GPa and 98.55 ± 7.38 GPa to 105.78 ± 9.98 GPa, respectively. The resistance to plasticity of ZLS significantly showed a second-order polynomial load relationship or a power law load dependency. Meanwhile, both the elastic and plastic displacements also significantly revealed power law load dependencies. However, the elastic and plastic deformation components were load-independent. Increased indentation loads resulted in significant decreases in the normalized elastic strain energy ( p  < 0.05) accompanied by significant increases in the normalized indentation absorbed energy (p  < 0.05). The equivalent elasticity and plasticity of ZLS during indentation occurred at 7.5 mN. The outcomes of this study provide insights into fabrication and mechanical functions of ZLS restorations, particularly facilitating abrasive machining in dental CAD/CAM processing in the ductile regime. [ABSTRACT FROM AUTHOR]

This paper reports the use of micro-slurry jet erosion (MSJE) on CAD/CAM lithium mesilicate glass ceramic (LMGC) that is capable of achieving the fracture-free surface quality. A computer-controlled MSJE process using a low-pressure and low-concentration alumina slurry was applied to diamond-ground LMGC surfaces with surface and subsurface damage. The MSJE processed and diamond-ground LMGC surfaces were examined using scanning electron microscopy (SEM) to examine surface morphology, fractures, and residual defects. 3D confocal laser microscopy (CLM) was used to quantitatively characterize all machined surface textures as a function of processing conditions. Our results show that surface and subsurface damage induced in diamond-ground surfaces were significantly diminished after 50-cycle MSJE processing. Fracture-free surfaces were obtained after 100 MSJE cycles. Our measured parameters of the 3D surface topography included the average surface roughness, maximum peak-valley height, highest peak height, lowest valley height, and kurtosis and absolute skewness of height distributions. All these parameters were significantly reduced with the increase of MSJE cycles. This work implies that MSJE promises to be an effective manufacturing technique for the generation of fracture-free LMGC surfaces which are crucial for high-quality monolithic restorations made from the material. [ABSTRACT FROM AUTHOR]

This clinical report presents the use of a modified polyetheretherketone (PEEK) post and core in order to support a lithium disilicate ceramic crown for a maxillary lateral incisor. When considering post-and-core restorations, material flexibility is essential to prevent root fractures. The low elastic modulus of PEEK (4 GPa) could result in lower root fracture rates, preserving tooth structure and favoring tooth re-restoration if the post fractures. PEEK is biocompatible, presents adequate bond strength with dentin when bonded with a resin cement, and can be used under ceramic restorations because of its white, esthetic color. PEEK posts and cores could also cost less when fabricated using common laboratory procedures. Polyetheretherketone (PEEK) posts and cores could be a viable alternative to rigid cast or zirconia posts, or even to fiber-reinforced composite posts, especially when combined with lithium disilicate crowns. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the 2-year performance of definitive implant- or tooth-supported three-unit fixed dental prostheses made of zirconia-reinforced lithium silicate placed to restore premolars and molars in clinical cases of partial edentulism. Materials and Methods: All patients received a three-unit fixed restoration made of monolithic, hot-pressed, zirconia-reinforced lithium silicate glass-ceramic. The restoration was cemented to two natural teeth or attached to two 3.5- or 4.5-mm-diameter square threaded, gritblasted, acid-etched integrated implants with a Morse taper connection. Peri-implant pocket depth and bone and soft tissue remodeling were recorded for 2 years at each follow-up visit. Esthetic, functional, and biologic United States Public Health Services (USPHS) parameters modified by the World Dental Federation study design were assessed yearly until the final follow-up appointment. At the time of placement of the definitive restorations and at the 2-year follow-up visit, the opposing dentitions were identified by type of restoration and supporting structures. Results: A total of 100 patients were consecutively enrolled in the period between June 2016 and July 2017, and 50 patients each received an implant-supported restoration (Group A) or a tooth-supported restoration (Group B). One (2%) of the 50 implant-supported prostheses fractured after 21 months of function. None of the other prostheses failed or became loose or detached. No significant differences involving probing levels or bone and soft tissue remodeling were found between the follow-up times. No cases of inflammation or infection of the mucosal cuff around the neck of the implants were recorded. The most common issue occurred immediately after placement of the prosthesis, when 3 patients (6%) from Group A and 4 patients (8%) from Group B asked for a modification of tooth shade. Conclusion: Implant-supported or tooth-supported three-unit fixed dental prostheses made of zirconia-reinforced lithium silicate can be used to successfully restore cases of posterior partial edentulism. The 2-year results of this report will be studied more in depth in ongoing long-term research. [ABSTRACT FROM AUTHOR]