Search Results (49)

Radiative cooling presents a promising passive cooling strategy, though its widespread adoption is often constrained by elevated costs and manufacturing complexities. This study introduces a cost-effective, scalable fabrication method for a composite membrane utilizing a spraying technique, and it was fabricated by spraying a mixture of modified nano-zirconia and ethylene-octene copolymer (POE), dissolved in petroleum ether, onto a polyethylene (PE) bubble film substrate. This composite membrane demonstrates a hydrophobic property, with a water contact angle of 100.6°. A cooling structure was formed by covering the composite membrane onto a polytetrafluoroethylene (PTFE) plate which served as an emitter, and the cooling power of this structure reaches 66.2 ± 4.3 W/m². Field tests reveal a temperature reduction of 3 ± 0.3 °C at noon and an average cooling effect of 4.7 ± 0.3 °C throughout the day, relative to ambient temperatures. This work advances the development of cost-effective, scalable radiative cooling technologies, holding promise for applications in building cooling and energy efficiency. Full article

Proton-exchange membranes (PEMs) are the pivotal components of vanadium redox flow batteries (VRFBs) and play a critical role in the comprehensive output performance of VRFB systems. Currently, the most widely commercialized membranes are Nafion series membranes produced by DuPont, Wilmington, DE, USA, but the high vanadium permeability and cost hinder their large-scale promotion. Hence, there is an active demand for developing a low-cost, high-performance, and energy-efficient PEM to promote the commercialization of VRFB systems. In this paper, sulfonated poly(ether ether ketone) (SPEEK) as matrix and zirconia nanoparticles as inorganic filler were used for composite modification to prepare a series of SPEEK–ZrO₂ organic–inorganic hybrid membranes for VRFBs. The thickness of these membranes was 50–100 μm. Compared with Nafion 115 (thickness 128 μm), composite membranes demonstrated obvious cost advantages. The results showed that the SP–Z-X series membranes had higher water uptake (53.26–71.1%) and proton conductivity (0.11–0.24 S cm⁻¹). SP–Z-5 displayed the best comprehensive output performance at 200 mA cm⁻² (CE: 99.01%, VE: 81.95%, EE: 81.11%). These hybrid membranes are very cost-effective and exhibit high potential for application in VRFB applications, and are expected to lead to the industrial application of VRFBs on a large scale. Full article

Water contamination due to microbial proliferation remains a critical global challenge, especially with increasing urbanization, industrial activities, and the use of agrochemicals, and it requires the development of innovative methods for their purification that are not harmful to the environment and humans. In this study, innovative antibacterial nanocomposite coatings, composed of zirconia and silver nanocluster, were developed and deposited via eco-friendly co-sputtering physical vapor deposition (PVD) method onto electrospun polymeric membranes (PCL and PAN-PCL) for water filtration applications. Structural and morphological analyses, including XRD and UV-Vis spectroscopy, confirmed the deposition of a composite coating, consisting of an amorphous zirconia matrix embedding silver nanoclusters, homogeneously distributed on one side of the polymeric fibers. Wettability evaluations showed an increase in hydrophobicity after coating, particularly affecting the filtration performance of the PCL membranes. Antibacterial tests revealed strong inhibition against Staphylococcus epidermidis (Gram-positive) and partial efficacy against Escherichia coli (Gram-negative). Filtration tests of contaminated solutions revealed a 99% reduction in Bacillus subtilis, significant inhibition of Listeria monocytogenes, and limited effect on E. coli, with no bacterial proliferation observed on the coated membranes. These results underscore the effectiveness of ZrO₂/Ag nanocomposites in enhancing microbial control and suggest a promising, scalable strategy for sustainable and safe water purification systems. Full article

Guided bone regeneration (GBR) is a procedure used for the treatment of bone deficiencies. Computer-Aided Designed–Computer-Aided Manufacturing (CAD-CAM) allows us to design a titanium mesh (TM) for GBR directly on a 3D bone defect model (3DBM). The design and printing of TMs are often delegated to specialized 3D printing centers, thus preventing the surgeon from controlling surgical parameters such as the thickness, pore width, texture, and stiffness. Therefore, we have here proposed a personalized digital workflow for designing a TM. The 3DBM was uploaded to an open-source CAD-CAM software. Following a GBR simulation, a TM was designed as a Standard Tesselation Language (STL) file and 3D laser-printed. The TM was applied to a graft of 50/50% autologous/xenogenic bone, fixed with a bone screw, and covered with a dermal membrane. No TM exposure was observed during the healing phase. The regenerated bone volume was 970 cc, and pseudoperiosteum was class 1. At the 6-month reentry, a 4.1 × 10 standard dental implant with a primary stability of 40 N/cm was placed and after 3 months a zirconia crown screw-on implant was placed. This proposed digital workflow enabled us to successfully tackle this clinical case. However, further clinical investigations will be necessary to confirm the long-term benefits of this procedure. Full article

Developing highly active and durable Pt-based electrocatalysts is crucial for polymer electrolyte membrane fuel cells. This study focuses on the performance of oxygen reduction reaction (ORR) electrocatalysts composed of Pt-Pd alloy nanoparticles on graphene nanoplates (GNPs) anchored with sulfated zirconia nanoparticles. The results of field emission scanning electron microscopy and transmission electron microscopy showed that Pt-Pd and S-ZrO₂ are well dispersed on the surface of the GNPs. X-ray diffraction revealed that the S-ZrO₂ and Pt-Pd alloy coexist in the Pt-Pd/S-ZrO₂-GNP nanocomposites without affecting the crystalline lattice of Pt and the graphitic structure of the GNPs. To evaluate the electrochemical activity and reaction kinetics for ORR, we performed cyclic voltammetry, rotating disc electrode, and EIS experiments in acidic solutions at room temperature. The findings showed that Pt-Pd/S-ZrO₂-GNPs exhibited a better ORR performance than the Pt-Pd catalyst on the unsulfated ZrO₂-GNP support and with Pt on S-ZrO₂-GNPs and commercial Pt/C. Full article

In recent years, ceramic membranes have received widespread focus in the area of liquid separation because of their high permeability, strong hydrophilicity, and good chemical stability. However, in practical applications, the surface of ceramic membranes is prone to be contaminated, which degrades the permeation flux of ceramic membranes during the separation process. Inspired by mussels, we imitate the biomimetic mineralization process to prepare a ceramic membrane of nano–silica on the pre-modified zirconia surface by co-deposited polydopamine/polyethyleneimine. The modified ceramic membranes were utilized for the purpose of oil–water separation. Separation performance has been tested using a disc ceramic membrane dynamic filtration device. The outcomes revealed an enhanced permeability in the modified membrane, measuring as 159 L m⁻² h⁻¹ bar⁻¹, surpassing the separation flux of the unmodified membrane, which was 104 L m⁻² h⁻¹ bar⁻¹. The permeation performance of the modified membrane was increased to 1.5 times. Modified ceramic membranes are highly resistant to fouling. From the beginning to the end of separation process, the oil rejection rate of the modified ceramic membrane is always higher than 99%. After a 2 h oil–water separation test run, modified ceramic membrane permeate flux can be restored to 91% after cleaning. It has an enormous capacity for application in the area of oil–water separation. Full article

Nanomaterials play a crucial role in various aspects of modern life. Zirconia nanoparticles, extensively employed in medicine for fortifying and stabilizing implants in reconstructive medicine, exhibit unique electrical, thermal, catalytic, sensory, optical, and mechanical properties. While these nanoparticles have shown antibacterial activity, they also exhibit cytotoxic effects on human cells. Our research focuses on understanding how the cells of the human immune system (both the innate response, namely HL-60 and U-937, and the acquired response, namely HUT-78 and COLO-720L) respond to the presence of zirconium (IV) oxide nanoparticles (ZrO₂-NPs). Viability tests indicate that ZrO₂-NPs exert the highest cytotoxicity on HL-60 > U-937 > HUT-78 > COLO 720L cell lines. Notably, concentrations exceeding 100 μg mL⁻¹ of ZrO₂-NPs result in significant cytotoxicity. These nanoparticles readily penetrate the cell membrane, causing mitochondrial damage, and their cytotoxicity is associated with heightened oxidative stress in cells. The use of ZrO₂-NP-based materials may pose a risk to immune system cells, the first responders to foreign entities in the body. Biofunctionalizing the surface of ZrO₂-NPs could serve as an effective strategy to mitigate cytotoxicity and introduce new properties for biomedical applications. Full article

The phase inversion tape casting has been widely used to fabricate open straight porous supports for solid oxide fuel cells (SOFCs), which can offer better gas transmission and minimize the concentration polarization. However, the overall weak strength of the macro-porous structure still limits the applications of these SOFCs. In this work, a novel SOFC supported by an ordered porous cathode membrane with a four-layer configuration containing a finger-like porous 3 mol% yttria- stabilized zirconia (3YSZ)-La_0.8Sr_0.2Co_0.6Fe_0.4O_3−δ (LSCF) catalyst, porous 8 mol% yttria-stabilized zirconia (8YSZ)-LSCF catalyst, and dense 8YSZ porous 8YSZ-NiO catalyst is successfully prepared by the phase inversion tape casting, dip-coating, co-sintering, and impregnation process. The flexural strength of the open straight porous 3YSZ membrane is as high as 131.95 MPa, which meets the requirement for SOFCs. The cathode-supported single cell shows a peak power density of 540 mW cm⁻² at 850 °C using H₂ as the fuel. The degradation mechanism of the SOFC is investigated by the combination of microstructure characterization and distribution of relaxation times (DRT) analysis. Full article

Thin, supported inorganic mesoporous membranes are used for the removal of salts, small molecules (PFAS, dyes, and polyanions) and particulate species (oil droplets) from aqueous sources with high flux and selectivity. Nanofiltration membranes can reject simple salts with 80–100% selectivity through a space charge mechanism. Rejection by size selectivity can be near 100% since the membranes can have a very narrow size distribution. Mesoporous membranes have received particular interest due to their (potential) stability under operational conditions and during defouling operations. More recently, membranes with extreme stability became interesting with the advent of in situ fouling mitigation by means of ultrasound emitted from within the membrane structure. For this reason, we explored the stability of available and new membranes with accelerated lifetime tests in aqueous solutions at various temperatures and pH values. Of the available ceria, titania, and magnetite membranes, none were actually stable under all test conditions. In earlier work, it was established that mesoporous alumina membranes have very poor stability. A new nanofiltration membrane was made of cubic zirconia membranes that exhibited near-perfect stability. A new ultrafiltration membrane was made of amorphous silica that was fully stable in ultrapure water at 80 °C. This work provides details of membrane synthesis, stability characterization and data and their interpretation. Full article

Root canal treatment represents a significant challenge as current cleaning and disinfection methodologies fail to remove persistent bacterial biofilms within the intricate anatomical structures. Recently, the field of nanotechnology has emerged as a promising frontier with numerous biomedical applications. Among the most notable contributions of nanotechnology are nanoparticles, which possess antimicrobial, antifungal, and antiviral properties. Nanoparticles cause the destructuring of bacterial walls, increasing the permeability of the cell membrane, stimulating the generation of reactive oxygen species, and interrupting the replication of deoxyribonucleic acid through the controlled release of ions. Thus, they could revolutionize endodontics, obtaining superior results and guaranteeing a promising short- and long-term prognosis. Therefore, chitosan, silver, graphene, poly(lactic) co-glycolic acid, bioactive glass, mesoporous calcium silicate, hydroxyapatite, zirconia, glucose oxidase magnetic, copper, and zinc oxide nanoparticles in endodontic therapy have been investigated in the present review. The diversified antimicrobial mechanisms of action, the numerous applications, and the high degree of clinical safety could encourage the scientific community to adopt nanoparticles as potential drugs for the treatment of endodontic diseases, overcoming the limitations related to antibiotic resistance and eradication of the biofilm. Full article

PVA (polyvinyl alcohol)-ZrP (PVA/ZrP) and Nafion^®/PVA-ZrP nanocomposite membranes were synthesised using the recasting method with glutaraldehyde (GA) as a crosslinking agent. The resulting nanocomposite membranes were characterised using a variety of techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The results of SEM revealed well-distributed zirconia phosphate (ZrP) within the membrane matrix, and the SEM images showed a uniform and dense membrane structure. Because ZrP nanoparticles are hydrophilic, the Nafion^®/PVA-ZrP nanocomposite membrane had a higher water uptake of 53% at 80 °C and higher 0.19 S/cm proton conductivity at room temperature than the commercial Nafion^® 117 membrane, which had only 34% and 0.113 S/cm, respectively. In comparison to commercial Nafion^® 117 membranes, PVA-ZrP and Nafion^®/PVA-ZrP nanocomposite membranes had a higher thermal stability and mechanical strength and lower methanol crossover due to the hydrophilic effect of PVA crosslinked with GA, which can make strong hydrogen bonds and cause an intense intramolecular interaction. Full article

The real-time monitoring of food freshness in refrigerators is of significant importance in detecting potential food spoiling and preventing serious health issues. One method that is commonly reported and has received substantial attention is the discrimination of food freshness via the tracking of volatile molecules. Nevertheless, the ambient environment of low temperature (normally below 4 °C) and high humidity (90% R.H.), as well as poor selectivity in sensing gas species remain the challenge. In this research, an integrated smart gas-tracking device is designed and fabricated. By applying pump voltage on the yttria-stabilized zirconia (YSZ) membrane, the oxygen concentration in the testing chamber can be manually tailored. Due to the working principle of the sensor following the mixed potential behavior, distinct differences in sensitivity and selectivity are observed for the sensor that operated at different oxygen concentrations. Typically, the sensor gives satisfactory selectivity to H₂S, NH₃, and C₂H₅OH at the oxygen concentrations of 10%, 30%, and 40%, respectively. In addition, an acceptable response/recovery rate (within 24 s) is also confirmed. Finally, a refrigerator prototype that includes the smart gas sensor is built, and satisfactory performance in discriminating food freshness status of fresh or semi-fresh is verified for the proposed refrigerator prototype. In conclusion, these aforementioned promising results suggest that the proposed integrated smart gas sensor could be a potential candidate for alarming food spoilage. Full article

Introduction: The objective of this study was to examine the effect of photofunctionalization on the soft-tissue contour formed at the interface of various abutment materials using end-point analyses obtained from the three-dimensional oral mucosal model (3D-OMMs). Methods: Commercially pure titanium (CPTi), alumina-toughened zirconia (ATZ), and yttria-stabilized zirconia (YSZ) made into discs shapes were classified into two groups: UV-treated (PTx) and non-treated (NTx). The materials in PTx groups were exposed to UV light for 12 min. Human gingival fibroblasts and TR146 epithelial cell lines co-cultured on the acellular dermal membrane were used to construct the 3D-OMM. After 4 days of culture, the discs were inserted into the holes prepared within the membrane of 3D-OMMs. The contour formed by the tissue was evaluated after 14 days of culture. Results: The UV treatment of abutment materials resulted in the formation of more non-pocket-tissue types among the PTx group (p = 0.002). Of all materials tested, soft tissue contour around YSZ showed higher scores for the non-pocket type in both non- and UV-treated groups. Conclusions: The non-pocket type of tissue attachment was frequently found in all surfaces modified by photofunctionalization, particularly zirconia. The 3D-OMM can be used to evaluate the biological endpoints of implant surface modifications. Full article

This paper presents the results of studying the phase composition, luminescent characteristics, and ionic conductivity of ceramic scandium-stabilized solid solutions of zirconium dioxide containing 9 and 10 mol% Sc₂O₃. Ceramic samples were prepared by sintering powders obtained by grinding melted solid solutions of the same composition. A comparative analysis of the obtained data with similar characteristics of single crystals has been carried out. Differences in the phase composition of ceramics and initial single crystals were found. The effect of the structure and properties of grain boundaries on the ionic conductivity of ceramic samples is discussed. It is shown that the differences in the ionic conductivity of ceramic samples and crystals are mainly due to changes in the structure and phase composition. Full article

Single-phase tungsten-doped lanthanum molybdenum oxide (La₂MoWO₉) ceramic powders were synthesized using the complex polymerization technique. Porous ceramic pellets were obtained by thermally removing graphite, which served as a pore former. The porous pellets were then impregnated with molten eutectic lithium-sodium-potassium carbonates. The energy dispersive X-ray analysis and scanning electron microscopy (FEG-SEM) images of the external and fracture surfaces of the La₂MoWO₉-(Li,Na,K)₂CO₃ composite dual-phase membrane revealed the percolation of the carbonate mixture through the pores. Electrochemical impedance spectroscopy measurements conducted at temperatures below and above the melting point of the eutectic carbonate composition demonstrated the contributions of oxygen and carbonate ions to the ionic conductivity of the dual membrane. The electrical conductivity of the carbonate ions within the membrane was continuously monitored for over 1300 h with negligible degradation, implying that the membrane could be used for long-term monitoring of CO₂ without aging effects. A comparison of FEG-SEM images taken before and after this endurance test suggested minimal fouling, indicating that the membrane could potentially replace similar zirconia- and ceria-based composite membranes. Full article