O3 Particles Research Articles

(La0.8Sr0.2)0.95Mn0.5Fe0.5O3Perovskite as anEfficient Bi‐Functional Electrocatalyst for Oxygen‐Involved Reaction and Zn‐Air Batteries

AbstractThe perovskite‐type oxide (La0.8Sr0.2)0.95Mn0.5Fe0.5O3, synthesized using lanthanum resources recovered from polishing powder waste and manganese resources obtained from zinc anode mud, was obtained via a facile polymer‐assisted combustion method, and further applied in zinc‐air batteries.The crystal phase and microstructure features of the thus‐obtained nanoparticles were characterized using X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS), and nitrogen adsorption‐desorption measurements. The results showed that the (La0.8Sr0.2)0.95Mn0.5Fe0.5O3 particles, with nanoscale size, possess a high specific surface area and a suitable Mn3+/Mn4+ molar ratio, which will benefit both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). As expected, the thus‐fabricated (La0.8Sr0.2)0.95Mn0.5Fe0.5O3 electrode exhibits a high current density of 71.2 and 85.2 mA cm−2 at −0.2 V and 0.6 V vs. Hg/HgO, respectively, which is superior to that of the commercial Pt/C catalyst (58 and 31 mA cm−2, respectively).Subsequently, this compound oxide can be an air electrode in a rechargeable zinc‐air battery. The assembled battery, using (La0.8Sr0.2)0.95Mn0.5Fe0.5O3 as the cathode, exhibits a discharge voltage of 1.05~1.16 V and a charge voltage of 2.03~2.13 V under 15 mA cm−2 for 150 h.The excellent electrochemical results presented in this study highlight the potential of (La0.8Sr0.2)0.95Mn0.5Fe0.5O3 as a highly efficient and commercially viable bifunctional electrocatalyst for applications in rechargeable zinc‐air batteries.

Self-consuming expansion stress construct piezoelectric field to accelerate anion for SiO/PbZr0.52Ti0.48O3 with persistent lithium storage performance

The high theoretical specific capacity and suitable working potential of silicon oxides (SiOx) making it one of the most promising candidates for the next generation of lithium-ion battery anode materials. However, the large-scale application of SiOx in lithium-ion battery anodes is hampered by the huge volume change (>200 %) during cycling process. This experiment adopts a method which is completely contrary to the traditional modification method——composite with piezoelectric materials to take advantage of this expansion. During the lithiation process, the significant volume expansion stress of SiO is transformed into a driving force by PbZr0.52Ti0.48O3 (PZT) particles that enhances the transport of Li+. The polarization of PZT particles occurs as a result of the consumption of mechanical stress caused by the expansion of SiO, leading to the generation of a piezoelectric potential. Since then, the volume expansion stress of SiO when deintercalating lithium is converted into a potential difference, which can promote the migration of Li+. This process not only reduces the volume expansion of SiO, but also promotes the mobility of Li+. The SiO/PZT anode shows an admirable cycle performance: The discharge capacity is 825.4 mA h g−1, and the capacity retention ratio is reach up to 92.5 % (200 mA g−1, 200 cycles). These findings illuminate the surface coupling approach employed to regulate the behavior of interfacial Li+ kinetics, while simultaneously enhancing the structural stability of alloy-based anodes. This research will undoubtedly capture the attention of researchers engaged in the study of multifunctional interface design for electrochemical systems.

Identification of yttrium oxide-specific peptides for future recycling of rare earth elements from electronic scrap.

Yttrium is a heavy rare earth element (REE) that acquires remarkable characteristics when it is in oxide form and doped with other REEs. Owing to these characteristics Y2 O3 can be used in the manufacture of several products. However, a supply deficit of this mineral is expected in the coming years, contributing to its price fluctuation. Thus, developing an efficient, cost-effective, and eco-friendly process to recover Y2 O3 from secondary sources has become necessary. In this study, we used phage surface display to screen peptides with high specificity for Y2 O3 particles. After three rounds of enrichment, a phage expressing the peptide TRTGCHVPRCNTLS (DM39) from the random pVIII phage peptide library Cys4 was found to bind specifically to Y2 O3 , being 531.6-fold more efficient than the wild-type phage. The phage DM39 contains two arginines in the polar side chains, which may have contributed to the interaction between the mineral targets. Immunofluorescence assays identified that the peptide's affinity was strong for Y2 O3 and negligible to LaPO4 :Ce3+ ,Tb3+ . The identification of a peptide with high specificity and affinity for Y2 O3 provides a potentially new strategic approach to recycle this type of material from secondary sources, especially from electronic scrap.

Using neural networks and remote sensing for spatio-temporal prediction of air pollution during the COVID-19 pandemic.

The study aims to monitor air pollution in Iranian metropolises using remote sensing, specifically focusing on pollutants such as O3, CH4, NO2, CO2, SO2, CO, and suspended particles (aerosols) in 2001 and 2019. Sentinel 5 satellite images are utilized to prepare maps of each pollutant. The relationship between these pollutants and land surface temperature (LST) is determined using linear regression analysis. Additionally, the study estimates air pollution levels in 2040 using Markov and Cellular Automata (CA)-Markov chains. Furthermore, three neural network models, namely multilayer perceptron (MLP), radial basis function (RBF), and long short-term memory (LSTM), are employed for predicting contamination levels. The results of the research indicate an increase in pollution levels from 2010 to 2019. It is observed that temperature has a strong correlation with contamination levels (R2 = 0.87). The neural network models, particularly RBF and LSTM, demonstrate higher accuracy in predicting pollution with an R2 value of 0.90. The findings highlight the significance of managing industrial towns to minimize pollution, as these areas exhibit both high pollution levels and temperatures. So, the study emphasizes the importance of monitoring air pollution and its correlation with temperature. Remote sensing techniques and advanced prediction models can provide valuable insights for effective pollution management and decision-making processes.

Ultrafine particulate matter exposure during second year of life, but not before, associated with increased risk of autism spectrum disorder in BKMR mixtures model of multiple air pollutants

Prenatal and early postnatal air pollution exposures have been shown to be associated with autism spectrum disorder (ASD) risk but results regarding specific air pollutants and exposure timing are mixed and no study has investigated the effects of combined exposure to multiple air pollutants using a mixtures approach. We aimed to evaluate prenatal and early life multipollutant mixtures for the drivers of associations of air pollution with ASD. This study examined 484 typically developing (TD) and 660 ASD children from the CHARGE case-control study. Daily air concentrations for NO2, O3, ultrafine (PM0.1), fine (PM0.1-2.5), and coarse (PM2.5-10) particles were predicted from chemical transport models with statistical bias adjustment based on ground-based monitors. Daily averages were calculated for each exposure period (pre-pregnancy, each trimester of pregnancy, first and second year of life) between 2000 and 2016. Air pollution variables were natural log-transformed and then standardized. Individual and joint effects of pollutant exposure with ASD, and potential interactions, were evaluated for each period using hierarchical Bayesian Kernel Machine Regression (BKMR) models, with three groups: PM size fractions (PM0.1, PM0.1-2.5, PM2.5-10), NO2, and O3. In BKMR models, the PM group was associated with ASD in year 2 (group posterior inclusion probability (gPIP) = 0.75), and marginally associated in year 1 (gPIP = 0.497). PM2.5-10 appeared to drive the association (conditional PIP (cPIP) = 0.64) in year 1, while PM0.1 appeared to drive the association in year 2 (cPIP = 0.76), with both showing a moderately strong increased risk. Pre-pregnancy O3 showed a slight J-shaped risk of ASD (gPIP = 0.55). No associations were observed for exposures during pregnancy. Pre-pregnancy O3 and year 2 p.m.0.1 exposures appear to be associated with an increased risk of ASD. Future research should examine ultrafine particulate matter in relation to ASD.

High-performance flexible piezocomposites based on an enhanced interfacial polarization effect via BCZT@Ag heterostructure design

Flexible piezoelectric energy harvesters (FPEHs) can convert mechanical energy into electric energy in a manner that powers electronic equipment and systems. Structural design of piezoelectric fillers in organic–inorganic piezocomposites is means of enhancing the power generation performance of FPEHs. Herein, a design strategy of piezoelectric fillers is proposed: decorating Ag nanoparticles onto Ba0.85Ca0.15Ti0.9Zr0.1O3 (BCZT) particles, forming a BCZT@Ag heterostructure, thus obtaining BCZT@Ag/poly(vinylidene fluoride) (PVDF) piezocomposites. An extremely high piezoelectric constant d33 of 34 pC/N is achieved in the BCZT@Ag/PVDF sample, which is 2.6 times higher than that of the BCZT/PVDF sample. The greatly improved piezoelectric properties are attributable to enhanced interfacial polarization via BCZT@Ag heterostructure design. More poling electric voltage is applied to the piezoelectric filler particles, resulting in substantially improved poling efficiency. This composite approach of introducing metal particles is a generic design method and can be extended to other organic–inorganic piezocomposite systems.

Yolk-Shell Structured ST@Al2 O3 Enables Functional PE Separator with Enhanced Lewis Acid Sites for High-Performance Lithium Metal Batteries.

Commercial polymer separators usually have limited porosity, poor electrolyte wettability, and poor thermal and mechanical stability, which can deteriorate the performance of battery, especially at high current densities. In this work, a functional polyethylene (PE) separator is prepared by surface engineering a layer of Ti-doped SiO2 @Al2 O3 particles (denoted as ST@Al2 O3 -PE) with strong Lewis acid property and uniform porous structure on one side of the PE separator. On the other hand, ST@Al2 O3 particles with abundant pore structures and large cavities can store a large amount of electrolyte, providing a shortened pathway for lithium-ion transport, and the Lewis acid sites and porous structure of the ST@Al2 O3 can tune Li plating/stripping behavior and stabilize the lithium metal anode. The ST@Al2 O3 -PE separators exhibit better ionic conductivity (5.55 mS cm-1 ) and larger lithium-ion transference number (0.62). At a current density of 1 mA cm-2 , Li/Li symmetric cells with ST@Al2 O3 -PE separator can be stably cycled for more than 400 h, and both lithium iron phosphate /Li cells and lithium cobaltate/Li cells with ST@Al2 O3 -PE separator have good cycling and rate performance. This work provides a new strategy for developing functional separators and promoting the application of lithium metal batteries.

A Novel Al-Cu Composite with Ultra-High Strength at 350°C via Dual-Phase Particle Reinforced Submicron-Structure.

Thermal stability determines a material's ability to maintain its performance at desired service temperatures. This is especially important for aluminum (Al) alloys, which are widely used in the commercial sector. Herein, an ultra-strong and heat-resistant Al-Cu composite is fabricated with a structure of nano-AlN and submicron-Al2 O3 particles uniformly distributed in the matrix. At 350°C, the (8.2AlN+1Al2 O3 )p /Al-0.9Cu composite achieves a high strength of 187MPa along with a 4.6% ductility under tension. The high strength and good ductility benefit from strong pinning effect on dislocation motion and grain boundary sliding by uniform dispersion of nano-AlN particles, in conjunction with the precipitation of Guinier-Preston (GP) zones, enhancing strain hardening capacity during plastic deformation. This work can expand the selection of Al-Cu composites for potential applications at service temperatures as high as ≈350°C.

Comprehensive temperature-stable energy storage performance in core-shell structural Na0.5Bi0.5TiO3@SrSn0.1Ti0.9O3-(Bi2O3-B2O3-SiO2) composites via morphology engineering

In this paper, morphology engineering was developed to optimize the overall temperature-stable energy storage performance of ceramic capacitors. First, SrSn0.1Ti0.9O3 (SST) particles were coated on Na0.5Bi0.5TiO3 (NBT) rods to form "core-shell" NBT@SST rods by a co-precipitation method to improve the relaxor behavior. And the rods were compounded with the Bi2O3-B2O3-SiO2 (BBS) glass to dense into NBT@SST-BBS composites. The nanorods morphology of ceramic grains can increase the charge storage sites to induce higher polarization value. The moderate-εr SST shell with highly lattice matching could lower the interfacial polarization between ceramic and glass phase so as to boost the breakdown strength. Comparatively, composites with nanorod morphology can reach the highest recoverable energy density of 2.19 J/cm3 at 229 kV/cm with superior temperature stability (Δε/ε150 °C ≤ 15% at 30–395 °C). We hope this work will give guidance to fabricate the next-generation dielectric capacitors through morphology engineering.

An Outlook into the Magnetic and Magnetocaloric Properties of Cr1.3Fe0.7O3

Herein, the magnetic and magnetocaloric properties of Cr1.3Fe0.7O3 particles are presented. The structural and oxidation states of the samples are confirmed from the X‐ray diffraction and X‐ray photoemission spectroscopy measurements. In addition, the thermomagnetization experiments reveal the coexistence of two spin reorientation, Morin transition, as well as Néel temperature below 300 K. Such complex magnetic behavior of the system can be ascribed to the metal–ligand–metal interaction caused both by Cr3+ and Fe3+ magnetic ions. The maximum magnetic entropy change estimated from the isothermal magnetization measurements is 0.056 J kg−1 K−1 at 41 K for an external magnetic‐field change of 70 kOe.

Highly efficient electrocaloric device based on composite materials with excellent heat transfer performance

Electrocaloric (EC) cooling technology is known for its efficiency and simplicity of the electricity-driving method. However, there still are many challenges and problems, i.e., the poor heat transfer of EC materials (polymers), and the limited electrocaloric temperature change, which result in the limited cooling efficiency and/or cooling power of the EC cooling prototypes. The lack of EC device with high cooling performance poses challenging obstacles for the industrial deployment of the EC cooling technology. In this work, we demonstrated that the fabrication of P(VDF-TrFE-CFE) nanocomposites with BaZr0.2Ti0.8O3 (BZT) particles is an efficient way to improve the heat transfer of EC materials without compromising EC capability. In order to valid the positive effect of developing the EC device rather than provide a pure material study, we developed a solid-fluid coupling EC cooling machine numerically. The introduction of BZT composites allows EC refrigeration devices to exhibit a good COP while maintaining a relatively high total cooling power (>150 W) when the temperature span is 10 K. Therefore, the composites exhibit great potential of ECE for future cooling applications.

Multifunctional bismuth oxide (Bi2 O3 ) particles: Evidence for selective melanoma therapy.

The current study investigates the therapeutic and optical properties of bismuth oxide (Bi2 O3 ) particles for selective melanoma therapy and prevention. The Bi2 O3 particles were prepared using a standard precipitation method. The Bi2 O3 particles induced apoptosis in human A375 melanoma cells but not human HaCaT keratinocytes or CCD-1090Sk fibroblast cells. This selective apoptosis appears to be associated with a combination of factors: increased particle internalization (2.29 ± 0.41, 1.16 ± 0.08 and 1.66 ± 0.22-fold of control) and enhanced production of reactive oxygen species (ROS) (3.4 ± 0.1, 1.1 ± 0.1 and 2.05 ± 0.17-fold of control) in A375 cells compared to HaCaT and CCD-1090SK cells, respectively. As a high-Z element, bismuth is also an excellent contrast agent for computer tomography, which renders Bi2 O3 a theranostic material. Moreover, Bi2 O3 displays high UV absorption and low photocatalytic activity compared to other semiconducting metal oxides, which opens further potential fields of application as a pigment or as an active ingredient in sunscreens. Overall, this study demonstrates the multifunctional properties of Bi2 O3 particles surrounding the treatment and prevention of melanoma.

The potential impact of biogenic volatile organic compounds (BVOCs) from terrestrial vegetation on a Mediterranean area using two different emission models

Biogenic Volatile Organic Compounds (BVOCs) emitted from vegetation are precursors of ozone (O3), photochemical oxidants and secondary organic aerosols (SOA) in the lower troposphere. The interaction between urban polluted air plumes originated along the coasts of the Mediterranean basin with biogenic emission occurring inland contributes to the occurrence of exceedances of the air quality standards for O3 and fine suspended particles (PM10, PM2.5). This interaction is favoured by prevailing sea-land breeze circulation during persistent high-pressure conditions. The actual contribution of BVOC to photochemical pollution is still uncertain because the approaches used to assess the emissions from terrestrial vegetation are quite different. There is some evidence in literature that BVOC emissions from Mediterranean vegetation is not accurately estimated by models based on the plant functional types (PFT) approach. To investigate these issues, a Plant Specific Emission Model (PSEM) was developed and applied to the Campania region in Southern Italy, for which a detailed vegetation inventory has been built. BVOC emission maps estimated by PSEM were compared with those generated using a PFT methodology, evidencing significant differences. BVOC emissions from the two models were then used to predict the concentrations of precursors and products of photochemical smog pollution over the Gulf of Naples (Italy) using a chemical-transport model. Simulations were performed during a period characterised by high pressure conditions that favour an enhanced O3 production under a sea-breeze circulation regime. VOCs concentration profiles predicted by the two models were compared with field data collected over Mount Vesuvius using a tethered balloon coupled with a PTR-MS. The results proved the better capability of PSEM to predict the concentrations of many BVOCs, including isoprene and some of its primary oxidation products over the measuring site, and suggested the significant potential of BVOC emission to produce SOA over the gulf of Naples.

Ultrahigh sensitive flexible sensor based on textured piezoelectric composites for preventing sports injuries

Textured piezoelectric composites (PCs) based on dielectrophoresis (DEP) reveal great merits in both improving sensitivity and maintaining flexibility, thus trending to be promising candidates for high sensitive flexible sensors. However, the DEP technique shows poor applicability in fabricating textured PCs with high filling content, which severely limits further improvement of piezoelectric performance. Herein, we propose a new strategy to enhance DEP force by decorating Cu nanoparticles on Ba0.85Ca0.15Ti0.9Zr0.1O3 (BCZT) particles, thus textured BCZT@Cu/PDMS PCs with high filling content are obtained. The results proved that the enhanced DEP force is contributed by the excellent conductivity and capability of distorted electric fields of decorated Cu nanoparticles. Consequently, an ultrahigh piezoelectric voltage constant (g33) of 720 × 10−3 Vm/N was achieved, which is much larger than that in other counterparts. Furthermore, the as-prepared piezoelectric sensor exhibits excellent sensitivity and flexibility, which can fit vulnerable joints like a band-aid seamlessly. On this basis, a flexible sport health monitoring system was developed, which shows great capabilities in real-time warn of the risky actions, rectification of wrong postures, and sports injury prevention.

LaFe0.8Co0.15Cu0.05O3 Supported on Silicalite-1 as a Durable Oxygen Carrier for Chemical Looping Reforming of CH4 Coupled with CO2 Reduction.

Chemical looping reforming of CH4 coupled with CO2 reduction is a novel technology for the utilization of CH4 and CO2. Here, we report a durable and outstanding LaFe0.8Co0.15Cu0.05O3/S-1 oxygen carrier at lower operating temperature to efficiently convert CH4 and utilize CO2. LaFe0.8Co0.15Cu0.05O3 showed a high CH4 reaction rate (7.0 × 10-7 mol·(g·s)-1), CO selectivity (84.2%), and CO yield (0.045 mol·g-1) at 800 °C. However, the reactivity of LaFe0.8Co0.15Cu0.05O3 reduced quickly with the redox cycles. The introduction of Silicalite-1 promoted the performance of the LaFe0.8Co0.15Cu0.05O3 perovskite oxygen carrier during the redox cycles. It can be attributed to the fact that under heat treatment, the LaFe0.8Co0.15Cu0.05O3 particles grew along the edge of Silicalite-1 and the LaFe0.8Co0.15Cu0.05O3 nanoparticles were homogeneously dispersed on the Silicalite-1 surface, which improved the thermal stability and reactivity of the oxygen carrier. In addition, the interface between Silicalite-1 and LaFe0.8Co0.15Cu0.05O3 nanoparticles also played important roles because the porous structure of Silicalite-1 could reduce the mass transfer restriction of the interface. In addition, Silicalite-1 also possessed high CH4 and CO2 adsorption selectivity, leading to higher reactivity.

Detailed insight into chromium species released from failed CoCrMo implants: Ex vivo periprosthetic tissues study.

This unique study provides information on Cr species and their distribution in periprosthetic tissues of patients with metal-on-polyethylene joint implants. Co-Cr-Mo alloy has been widely used in joint replacement and represents a source of metal derived species. In the case of chromium, previous studies on periprosthetic tissues revealed mainly Cr(III) distribution, whereas the potential release of carcinogenic Cr(VI) species has been still a subject of debate. Here, an analytical approach utilizing speciation and fractionation was developed to analyze periprosthetic tissue samples collected from wide range of patients with failed total hip or knee replacements. The results reveal that Cr(III) is mainly released in the form of insoluble CrPO4 and Cr2 O3 particles. The highest Cr contents were found in periprosthetic tissues of patients suffering from aseptic loosening and having more Cr-based implants in the body. Cr species penetrated tissue layers, but their levels decreased with the distance from an implant. The detailed speciation/fractionation study carried out using the set of consecutive periprosthetic tissues of a patient with extensive metallosis showed the presence of trace amounts of free Cr(III), nanoparticles, and metal-protein complexes, but the majority of Cr still occurred in CrPO4 form. Carcinogenic Cr(VI) species were not detected. Up to date, there is no published human tissue study focused on the detailed speciation of both soluble and insoluble Cr-based species in the context of failing total hip and knee replacements.

A Single-Layer Composite Separator with 3D-Reinforced Microstructure for Practical High-Temperature Lithium Ion Batteries.

Incorporation of ceramic materials into separators has been frequently applied in both research and industry to improve the overall high-temperature performances of lithium ion batteries. However, inorganic ceramic particles tend to form aggregation in separators and even fall off in the separator matrix due to the inferior combination between ceramic particles and polymer matrix, giving rise to a decrease in separator porosity and thus the degradation of battery performances. Herein, a single-layer core-shell architecture is designed to reinforce the polymer matrix through encircling Al2 O3 particles by poly(vinylidene fluoride) with strong inter-molecular interaction. The 3D-reinforced microstructure effectively improves pore distribution and thermal stability to resist the dimensional deformation at high temperatures, thus giving rise to a high Coulombic efficiency of 99.16% and 87.5% capacity retention after 500 cycles at 80°C for LiFePO4 /Li batteries. In particular, the excellent performances of the proposed separator microstructure are confirmed with a thickness value of commercial separators. This work provides a promising strategy to fabricate a core-shell structural composite separator for stable lithium ion batteries at high temperatures.

Surface Characteristics and Adhesion of Veneering Composite Resin to PAEK-Based Substructure Restorative Materials.

To evaluate and compare the shear bond strength (SBS) of composite veneering material to polyetherketoneketone (PEKK), polyetheretherketone (PEEK), zirconia (YZ), and nickel-chromium alloy (NiCr) substructure restorative materials. Forty samples (12 × 2 mm) were prepared from four materials: PEKK, PEEK, zirconia, and NiCr alloy (n = 10). The Vickers hardness was evaluated before preparing the surface for bonding by shot-blasting using 110 μm Al2 O3 particles. The surface roughness (Ra) of each sample was determined using a noncontact optical profilometer. The veneering resin was bonded onto each sample following primer application. The prepared samples were then subjected to an SBS test using a universal testing machine at 0.5 mm/min crosshead speed. Failure modes and surface topography following debonding were assessed. The data were statistically analyzed using ANOVA and Tukey'spost-hoccomparison test (p < 0.05). RESULTS: The highest and lowest mean surface roughness was observed in PEEK (3.45 ±0.13 μm) and NiCr (1.87 ±0.07 μm) materials, respectively. A significant difference in roughness values was observed between the materials except for NiCr and YZ (p = 0.547). Concerning SBS, PEEK and NiCr exhibited the highest (16.23 ±0.96 MPa) and lowest (10.1 ±0.63 MPa) values. The mean difference in SBS indicated a statistically significant difference between the material groups (p < 0.01). PEKK materials demonstrated significantly lower SBS than PEEK and significantly higher SBS values than conventional zirconia and alloy materials. A positive and significant correlation between mean roughness and SBS was observed, but the causality could be either intrinsic to the material or the roughness.

Enhanced Output Performance of Piezoelectric Nanogenerators by Tb-Modified (BaCa)(ZrTi)O3 and 3D Core/shell Structure Design with PVDF Composite Spinning for Microenergy Harvesting.

Flexible piezoelectric nanogenerators (PENG) have attracted great attention due to their stable electrical output and promising applications in the Internet of Things. To develop a high-performance PENG, a significant relationship among material, structure, and performance precipitates us to design its rational construction. Herein, Tb-modified (BaCa)(ZrTi)O3 (BCZT) particles have been fabricated into a 3D structure (3D-Tb-BCZT) by the freeze-drying method, and the innovative 3D core/shell structure of 3D-Tb-BCZT-coated 3D-Tb-BCZT/PVDF composite fibers was carried out through the coaxial electrospinning method. The innovative structure can significantly enhance correlation between adjacent piezoelectric particles and improve stress-transfer efficiency, which can be proven by experimental results and COMSOL simulation. As a result, the improved PENG shows a significantly enhanced output of 48.5 V and 3.35 μA as compared to the PENG with the conventional electrospinning process (15.6 V and 1.32 μA). Due to the advantages of light weight, soft flexibility, and high deformation sensitivity of composite fibers, PENG-based fibers can harvest various mechanical energies in daily life such as biological motion, noise vibration, and wind energies. More importantly, the PENG is sufficient enough to power an electronic device for sustained operation by capturing wind energies through power management circuit design, which further promotes the practical application process of a self-powered system.

Evaluation of Microshear Bond Strength of Four Different CAD-CAM Polymer-Infiltrated Ceramic Materials after Thermocycling.

To evaluate the bond strength of three monolithic hybrid ceramics/resin nanoceramics and a zirconia-reinforced lithium silicate to resin cement after thermocycling. Using four materials, including Vita Enamic (VITA Zahnfabrik), Lava Ultimate (3M ESPE), Crystal Ultra (Digital Dental), and Vita Suprinity (VITA Zahnfabrik), 64 specimens were prepared with dimensions of 4 mm × 3 mm × 1.5 mm. Vita Suprinity samples were sintered at 840°C for 8 min. After polishing and cleaning all the samples in each group (n = 16), they were subjected to their recommended surface treatment: 10% hydrofluoric acid for Vita Enamic (60s) and Vita Suprinity (20s); air abrasion of Lava Ultimate and Crystal Ultra with 50 u Al2 O3 particles. Then, tygon tubes were filled with dual cure resin cement (Panavia F2.0), cured and then subjected to thermal cycling (2000 cycles; 5-55°C). The microshear bond strength was measured using microtensile testing machine. The data were analyzed using Welch and Games-Howell tests (α = 0.05). The mode of failure was also evaluated using a stereomicroscope. The highest and the lowest mean microshear bond strength belonged to the Crystal Ultra (7.71 ± 1.54 MPa) and Vita Suprinity (4.73 ± 1.87 MPa) groups, respectively. The differences between groups were significant and Crystal Ultra had higher bond strength in comparison to all three materials (p < 0.05). Hybrid ceramics showed higher bond strength to resin cements in comparison to resin nanoceramics and zirconia-reinforced lithium silicate materials.