Denitrification enhanced by composite carbon sources in AAO-biofilter: Efficiency and metagenomics research.

Nitrogen removal from domestic sewage is usually limited by insufficient carbon source and electron donor. An economical solid carbon source was developed by composition of polyvinyl alcohol, sodium alginate, and corncob, which was utilized as external carbon source in the anaerobic anoxic oxic (AAO)-biofilter for the treatment of low carbon-to-nitrogen ratio domestic sewage, and the nitrogen removal was remarkably improved from 63.2% to 96.5%. Furthermore, the effluent chemical oxygen demand maintained at 35 mg/L or even lower, and the total nitrogen was reduced to less than 2 mg/L. Metagenomic analysis demonstrated that the microbial communities responsible for potential denitrification and organic matter degradation in both AAO and the biofilter reactors were mainly composed of Proteobacteria and Bacteroides, respectively. The solid carbon source addition resulted in relatively high abundance of functional enzymes responsible for NO3--N to NO2--N conversion in both AAO and the biofilter reactors, thus enabled stable reaction. The carbon source addition during glycolysis primarily led to the increase of genes associated with the metabolic conversion of fructose 1.6P2 to glycerol-3P The reactor maintained high abundance of genes related to the tricarboxylic acid cycle, and then guaranteed efficient carbon metabolism. The results indicate that the composite carbon source is feasible for denitrification enhancement of AAO-biofilter, which contribute to the theoretical foundation for practical nitrogen removal application.

Impact of signal-to-noise ratio and contrast definition on the sensitivity assessment and benchmarking of fluorescence molecular imaging systems.

Significance: Standardization of fluorescence molecular imaging (FMI) is critical for ensuring quality control in guiding surgical procedures. To accurately evaluate system performance, two metrics, the signal-to-noise ratio (SNR) and contrast, are widely employed. However, there is currently no consensus on how these metrics can be computed. Aim: We aim to examine the impact of SNR and contrast definitions on the performance assessment of FMI systems. Approach: We quantified the SNR and contrast of six near-infrared FMI systems by imaging a multi-parametric phantom. Based on approaches commonly used in the literature, we quantified seven SNRs and four contrast values considering different background regions and/or formulas. Then, we calculated benchmarking (BM) scores and respective rank values for each system. Results: We show that the performance assessment of an FMI system changes depending on the background locations and the applied quantification method. For a single system, the different metrics can vary up to ∼ 35 dB (SNR), ∼ 8.65 a . u . (contrast), and ∼ 0.67 a . u . (BM score). Conclusions: The definition of precise guidelines for FMI performance assessment is imperative to ensure successful clinical translation of the technology. Such guidelines can also enable quality control for the already clinically approved indocyanine green-based fluorescence image-guided surgery.

Development and antimicrobial activity of composite edible films of chitosan and nisin incorporated with perilla essential oil-glycerol monolaurate emulsions.

Aquatic products are highly susceptible to spoilage, and preparing composite edible film with essential oil is an effective solution. In this study, composite edible films were prepared using perilla essential oil (PEO)-glycerol monolaurate emulsions incorporated with chitosan and nisin, and the film formulation was optimized by response surface methodology. These films were applied to ready-to-eat fish balls and evaluated over a period of 12 days. The films with the highest inhibition rate against Staphylococcus aureus were acquired using a polymer composition of 6 µL/mL PEO, 18.4 µg/mL glycerol monolaurate, 14.2 mg/mL chitosan, and 11.0 µg/mL nisin. The fish balls coated with the optimal edible film showed minimal changes in appearance during storage and significantly reduced total bacterial counts and total volatile basic nitrogen compared to the control groups. This work indicated that the composite edible films containing essential oils possess ideal properties as antimicrobial packaging materials for aquatic foods.

Retention of strength and ion release of some restorative materials.

This study aimed to investigate the retention of strength in accelerated aging condition and ion release from an experimental fiber-reinforced bioactive flowable composite resin (Bio-SFRC), comparing it with various commercially available ion-releasing materials. The flexural strength of Bio-SFRC and other materials (Biodentine, TheraCal LC, Fuji II LC and Surefil one) was evaluated (n = 8) before and after hydrothermal accelerated aging. Ion concentrations of silica and phosphorus were measured after 1, 2, 3, 4, 7, 10, 14, and 21 days of specimen immersion in simulated body fluids (SBF) using UV-Vis spectrometry. In addition, ion release and pH change were studied in a continuous dynamic system in SBF over a period of 72 h. SEM and EDS were used to evaluate the microstructure on the top surface of the materials after SBF immersion. Data were statistically analyzed using variance ANOVA analysis (p = 0.05). Bio-SFRC showed higher flexural strength before (134.9 MPa) and after (63.1 MPa) hydrothermal aging compared to other tested materials (p < 0.05). Flexural strength significantly decreased after aging (p < 0.05) except for Fuji II LC which showed no significant differences. Ion release data showed that experimental Bio-SFRC slowly released phosphate ions. Biodentine and TheraCal LC had the strongest ability to form calcium phosphate precipitation on the material surface. Phosphate ion release cannot be detected clearly from these materials. Surefil one and Fuji II LC were more stable materials without any observable ion release. The advantages of fiber containing structure and slow release of ions suggest that experimental Bio-SFRC is a promising bioactive material to provide ions for mineralization of surrounding tissues, and keeping the durability of the materials at higher level than that of other tested materials.

Improved complete ensemble empirical mode decomposition with adaptive noise and composite multiscale permutation entropy for denoising blast vibration signal.

Monitoring the building blast vibration signal is an efficient way to determine the power of blast vibration hazards. Due to the harsh measurement environment, noise is inevitably introduced into the recorded signals. This research presents a denoising approach based on Improved complete ensemble empirical mode decomposition with adaptive noise(ICEEMDAN) and Composite Multiscale Permutation Entropy (CMPE). First, the noisy blast vibration signal is decomposed into different intrinsic mode functions using ICEEMDAN; then multiple intrinsic mode functions (IMFs) are separated into pure and noisy using CMPE, the noisy IMFs are denoised using wavelet thresholding; finally the blast wave is reconstructed using the pure and denoised mixed IMFs. The proposed approach was compared with four other approaches (CEEMDAN-CMPE, VMD-CMPE, SVMD-CMPE, and WST). The results indicate that the proposed approach has better performance and can be considered as an effective denoising method for building blast vibration signals.

Pulsed electroplating of ZrO2-reinforced Ni-Cr alloy coatings from the duplex complexing agents-containing bath for engineering applications: Importance of operating conditions.

The progress in tribocorrosion performance of the engineering parts is in dire need of improving their surface properties. In the present contribution, Ni-Cr-ZrO2 layers were electrodeposited on St37 steel. The stress was put on optimizing the process factors, including the parameters involved in pulsed current electrodeposition and level of the ZrO2 reinforcing nanoparticles (0-20 g/L) in the bath. The surface characteristics of the electrodeposits were evaluated using FESEM, EDS, AFM, and XRD. The tribomechanical characteristics of the films were determined using a Vickers microhardness tester and pin-on-disk apparatus. The electrochemical behavior of the samples was studied using OCP, EIS, PDP, and immersion techniques. The results demonstrated that the included ZrO2 nanoparticles led to more homogenous, rougher, and defect-free surfaces, while they did not change the phase composition of the alloy electrodeposits. The polarization resistance of the Ni-Cr alloy coating increases by 6.7 times when 10 g/L of the reinforcing nanoparticles is added to the electrolyte. A decrease of ≈42 % in the mean COF value was obtained by the incorporation of 10 g/L ZrO2 nanoparticles into the plating bath. The coating system developed holds the promise to address both technical requirements and health concerns.

Preparation, characterization, and binding mechanism of quercetin-loaded composite nanoparticles based on zein-soybean protein isolate.

In this study, quercetin (Que) was encapsulated for controlled release during gastrointestinal digestion using zein-soy isolate protein (SPI) composite nanoparticles that were made following an antisolvent precipitation technique. The average particle size of the composite nanoparticles ranged from 182.1 to 230.9 nm, and the polydispersity index (PDI) was small (0.105-0.323). The microstructure revealed that the composite nanoparticles were spherically distributed and that Que. was embedded on the surface of the nanoparticles. Que. has an encapsulation efficiency of up to 93.3 %. Spectrum analysis, molecular docking and zeta potential measurements revealed that the interactions between the composite nanoparticles and Que. occurred mainly through hydrophobic interactions, hydrogen bonding, and electrostatic interactions. Compared with single zein nanoparticles, the composite nanoparticles showed a significant and controlled release of Que. during the whole simulated gastrointestinal digestion process. This study provides a novel method for the development of a controlled-release drug delivery system for controlling the release of Que.

Research on ultrasonic-assisted vibration multi-cycle compaction method of flexible guided 3D weaving.

The structure of three-dimensional (3D) preforms is the key to the performance of 3D reinforced composites. In order to improve the quality and efficiency of manufacturing, this paper originally proposes the ultrasonic vibration-assisted multi-cycle compaction method. Ultrasonic vibrations are applied, using a resonant 40 kHz compactor, to the compaction of 3D carbon fiber preform. Compared to the traditional method, the ultrasonic vibration-assisted multi-cycle compaction method can accelerate stress relaxation and reduce preform springback. The microstructure of preform is observed using x-ray computer tomography imaging. It elucidates the mechanism by which ultrasonic vibration promotes fiber slippage. The compaction forming experiment of preforms has proven that the ultrasonic vibration-assisted multi-cycle compaction method can reduce the compaction time, improving the forming quality. This can improve the technical support for the improvement of the manufacturing level of the 3D preform.

Highly Interconnected Thermal Conduction Highway for Highly Thermally Conductive and Mechanically Strong Polymeric Composites.

Industrial implementation of highly thermally conductive polymeric composites has been hindered by several hurdles, such as the low intrinsic thermal conductivity (TC) of polymers, the use of expensive thermally conductive fillers, and difficulty in processing composites with high filler loading. In this study, we introduce a straightforward fabrication method for a high TC polymeric composite with a programmed internal structure of a highly interconnected thermal conduction highway (HITCH) by the simple addition of partially cured resin fragments into the conventional filler/resin combination. Critical variables, such as the concentration of the added resin fragments and the local concentration of hexagonal boron nitride (hBN) in the HITCH, as well as the packing density of the fragments, were systematically tuned to maximize the TC with the use of the least amount of the filler. Careful choice of the compositions enabled a significant TC enhancement of the composite by 2.6 times (6.5 W/mK) compared to the value of the conventional composite at the same overall concentration of hBN (∼2.5 W/mK). Finally, a composite with high TC (∼12 W/mK) and strong tensile strength (∼22.6 MPa), which is good enough for most practical thermal management applications, could be successfully fabricated with the use of the least amount of the filler (∼34 wt %). The comprehensive study of the HITCH composite here can be easily extended to other combinations with various fillers and matrices and may provide a library to researchers looking for advanced materials for future thermal management systems.

Toughness and Thermoresponsive Hydrogel for Sandwich Smart Window with Adaptive Solar Modulation and Energy Saving.

Thermochromic hydrogels with self-regulating solar transmittance are gaining increasing attention due to their significant potential in the fields of smart windows and energy conservation. Smart windows incorporating viscosity-tough hydrogels as an interlayer exhibit enhanced advantages in resisting external forces. In this study, a tough and thermoresponsive composite hydrogel was developed by incorporating poly(N-isopropylacrylamide) nanoparticles (PNIPAM NPs) and W-doped VO2 into a polyacrylamide-agar (PAM-Agar) double network hydrogel. Upon solar irradiation, thermochromism of PNIPAM NPs could regulate the visible light transmittance of the composite hydrogel and the photothermal effect of W-VO2 contributes to the optical regulation and NIR shielding. The smart window, with the composite hydrogel as an interlayer, demonstrates excellent optical modulation capabilities, with a luminous transmittance (Tum(20 °C)) of 86.81%, high light modulation (ΔTum = 78.89%), a high solar modulation (Tsol) of 83.59%, and a lower critical solution temperature (LCST) of 32.6 °C. The composite hydrogel's superior toughness (0.215 MJ/m3) also enhances the impact resistance of the smart window glass. Additionally, the adhesion between the hydrogel and the glass, with a maximum peeling force of up to 151 N/m (attributed to interactions between the amide groups and the silicon hydroxyl groups), was confirmed through a falling ball experiment. Moreover, the hydrogel exhibits a certain degree of thermal insulation, further promoting its utility in energy-saving applications. In conclusion, this study highlights the significant potential of such composite hydrogels in the development of smart windows for energy-efficient buildings.

Mathematical Modeling and Experimental Investigation of the Dynamic Response for an Annular Circular Plate Made of Glass/Polyester Composite Under Different Boundary Conditions.

Fiber-reinforced elastic laminated composites are extensively used in several domains owing to their high specific stiffness and strength and low specific density. Several studies were performed to ascertain the factors that affect the composite plates' dynamic properties. This study aims to derive a mathematical model for the dynamic response of the processed composite material in the form of an annular circular shape made of polyester/E-glass composite. The mathematical model was developed based on modified classical annular circular plate theory under dynamic loading, and all its formulas were solved using MATLAB 2023. The mathematical model was also verified with real experimental work involving the vibration test of the fabricated composite plate. The composite plate was processed by reinforcing the polyester matrix with E-glass fibers with a 50% volume fraction each by using the handy lay-up method. After fabrication, the composite plate was tested with a universal vibration tester, where the plate was impacted and released to free vibration, and the deflection was measured experimentally to compare it with the theoretical value calculated from the derived model. The plate was tested under two boundary conditions, namely, simply and built-in supported. The findings show good agreement between theoretical and experimental plate deflections at different angles, particularly at built-in supported boundary conditions. Also, a higher natural frequency was recorded at this condition compared to others, and this may be ascribed to the higher shear stresses involved due to large moments at the ends along with supporting. Meanwhile, the real experimental spectrum of the built-in condition was higher than others, as the sig view curve revealed.

Microwave-Assisted Self-Healable Biovitrimer/rGO Framework for Anticorrosion Applications.

Microwave-stimulated smart self-healable polymeric coatings with significant protective technology against corrosion have been developed in this work. Herein, a generous approach is strategized to generate linseed oil-derived epoxy composites embedded with reduced graphene oxide (rGO) as a nanofiller in the shielding network. The composite showed excellent self-healing and shape memory properties when irradiated with microwaves due to the dynamic reversible nature of the disulfide covalent bond exchange mechanism. The network also has improved thermomechanical properties and thermal stability, with a storage modulus of 20.8 GPa and a low activation energy of 79 kJ/mol, indicating a fast disulfide dynamic exchange reaction. The amine functionality in the composite contributes to excellent corrosion protection, with 99.9% protection efficiency, as validated via a Tafel plot. The composite also showed excellent hydrophobicity, with a 131° contact angle. This study provides insights into the engineering and application of smart materials as anticorrosive coatings.

Mechanically durable tri-composite polyamide 6/hematite nanoparticle/tetra-n-butylammonium bromide (PA6/α-Fe2O3/TBAB) nanofiber based membranes for phosphate remediation.

Essential properties for a Point of Use (POU) water filter include maintaining high removal capacity and rate, with excellent mechanical properties to withstand pressure drop. Herein, mechanically robust tri-composite polyamide 6/iron oxide nanoparticles/tetra-n-butylammonium bromide (PA6/α-Fe2O3/TBAB) nanofiber composite membranes were electrospun for phosphate (P) remediation, where the diameter and composition were tuned by controlling solution compositions and electrospinning conditions. Tri-composite composition and morphology affect phosphate uptake where the adsorption capacity followed Langmuir isotherm whereas the adsorption kinetics followed pseudo second order behavior. Mechanical properties (i.e., Young's Modulus (E) and toughness) were significantly influenced by the composition and morphology of the tri-composite, as well. Although additional TBAB and iron oxide decreased toughness, there are optimum composition ranges which resulted in maximum Young's Modulus. Of the synthesized nanofiber membranes, PA6/α-Fe2O3/TBAB nanofibers with 17% α-Fe2O3 and 2% TBAB showed excellent phosphate uptake capacity [i.e., 8.9 mg/g (52 mg of P/g of α-Fe2O3)] while it is bendable, stretchable, and able to plastically deform without fracturing (i.e., Young's modulus of 2.06 × 108 Pa and Toughness of 1.35 × 106 J m-3). With concerns over the impact of P on water resources and the long-term availability of limited P resources, this tri-composite membrane is well suited for applications in both wastewater treatment and resource recovery.

Thermal buckling analysis of reinforced composite conical shells in acidic environments: Numerical and experimental investigation on the effects of nanoparticles.

This study investigates the effects of acid penetration and temperature on the buckling behavior of conical composite shells, to enhance structural integrity and longevity in corrosive environments. The study explores the impact of acid exposure on thermal properties and examines the efficacy of incorporating nano-silica and nano-clay in preventing buckling. Additionally, it analyzes the influence of nanoparticles on the thermal, moisture, and mechanical properties of the composite material. Experimental assessments are conducted to measure material properties during exposure to a sulfuric acid solution, providing a comprehensive understanding of the material's behavior under extreme conditions. However, due to the complexity of investigating the combined effects of temperature, acid, and nanoparticles on composite shell buckling, a combined numerical and experimental approach is adopted to predict the critical buckling load. To this end, equations of conical shells under hygrothermal loading are derived, and the critical buckling load is determined through pre-buckling analysis. The Generalized Differential Quadrature (GDQ) method is employed to solve the hygrothermal buckling of the composite shell using experimentally obtained material properties. Comparative results are presented for different nanoparticles, shell geometries, and exposure times in acidic environments. The experiments reveal that adding nanoparticles enhances mechanical properties and reduces thermal and moisture expansion coefficients. Conversely, the acidic conditions deteriorate these properties. Numerical analysis demonstrates that incorporating nanoparticles significantly increases the critical buckling temperature, with nano-silica and nano-clay particles resulting in an 11.5 % and 34.2 % increase, respectively. However, acidic environments decrease the critical buckling temperature, with reductions of 32 % for unreinforced, 29 % for nano-silica reinforced, and 46 % for nano-clay reinforced composites after three months of exposure.

A transformation and auxiliary extraction of Cr during electrokinetic removal of Cr-contaminated multilayer composite soil chamber.

Multilayer composite soil chamber was proposed to extract the Cr of contaminated site soil and insight into transformation of Cr fractionation associated with valence states. The variations of current, soil pH and moisture content were explored, as well as the migration of Cr fractionation and redistribution of Cr. Results indicated that duration of half peak current could be used to adjust treatment time and it varied among different composite ways. Moreover, extraction efficiency of Cr in soil near cathode was relatively higher and reached 60% when citric acid was used. Citric acid could promote the transformation between different Cr fractionations or different valence states. It could also improve the desorption of Cr, and could prevent excessive fluctuations of moisture content at the same time. Cr redistributed acrossed the soil chamber after extraction. When deionized water was used, Cr(VI) significantly migrated toward anode mainly in the form of exchangeable fractionation (EXC) while Fe-Mn oxides fractionation (Fe-Mn) which may be in the form of cationic Cr(III) hydroxides migrated toward cathode. When using citric acid, fractionations that were difficult to migrate of Cr, especially for Fe-Mn in site soils could be activated and became EXC and carbonate fractionation (CAR), then migrated to the anode or cathode. The migration of exchangeable Cr(III) was dramatically enhanced. But the use of citric acid could cause Cr(VI) transformation to Cr(III) near anode. In addition, during the migration process, EXC could go back to Fe-Mn again or transform to residue fractionation (RES).

Application of Silk Light Chain on a Graphene Composite Surface: A Molecular Dynamics and Electrochemical Experiment.

The surface functionalization of pristine graphene (PG) with beneficial biocomposites is important for biomedical and tissue engineering. This study introduces silk light chain as novel biocomposites to increase the biocompatibility of PG. We explored the supramolecular structures of the silk heavy and light chains. Through molecular dynamics, we compared and analyzed the structural effects and binding mechanisms of these domains in their interaction with PG. Our results highlighted a significant hydrophobic interaction between the silk light chain and PG, without structural collapse. The supramolecular structure of the silk light chain was identified by analyzing the amino acids bound to PG. Moreover, using the silk light chain, the hydrophobic surface of PG has changed to a hydrophilic surface, and the silk light-chain-PG electron transfer rate was evaluated for the graphene congeners: graphene oxide (GO) and reduced graphene oxide. Therefore, we are confident that the dispersibility and biocompatibility of PG can be increased using silk light chains, which will contribute to broadening the field of application of PG-based materials.

Compositional Engineering of Lithium Metal Anode for High-Performance Garnet-Type Solid-State Lithium Battery.

Garnet-type solid-state lithium batteries (SSLBs) possess excellent potential owing to their safety and high energy density. However, fundamental barriers are deficient cycling stability and poor rate capability. The main concern lies in generating voids at the Li|garnet interface during Li stripping, stemming from the sluggish diffusion of Li atoms inside the bulk Li metal. Herein, a composite anode (AN@Li) containing Li-Al alloy, Li3N, and LiNO2 is designed by introducing aluminum nitrate into molten Li. The lower interfacial formation energies exhibited by Li-Al alloy, Li3N, and LiNO2 with garnet solid-state electrolyte (SSE) enhance the wettability of AN@Li toward SSE. Meanwhile, it affords efficient conductive pathways that facilitate Li+ diffusion in the bulk anode (not just on the surface). Impressively, the resulting symmetric cell with AN@Li electrodes achieves high critical current density (1.95 mA cm-2) and long cycle life (6000 h at 0.3 mA cm-2). The SSLB coupled with LiFePO4 cathode and AN@Li anode enables stable cycling for 200 cycles at a high rate of 1 C with a retention of 96% and exhibiting outstanding rate capability (145.9 mAh g-1 at 2 C). This work provides practical insights for producing high-performance lithium metal anode for advanced garnet-type SSLBs.

Organic-Inorganic Copolymerization Induced Oriented Crystallization for Robust Lightweight Porous Composite.

Porous composites are important in engineering fields for their lightweight, thermal insulation, and mechanical properties. However, increased porosity commonly decreases the robustness, making a trade-off between mechanics and weight. Optimizing the strength of solid structure is a promising way to co-enhance the robustness and lightweight properties. Here, acrylamide and calcium phosphate ionic oligomers are copolymerized, revealing a pre-interaction of these precursors induced oriented crystallization of inorganic nanostructures during the linear polymerization of acrylamide, leading to the spontaneous formation of a bone-like nanostructure. The resulting solid phase shows enhanced mechanics, surpassing most biological materials. The bone-like nanostructure remains intact despite the introduction of porous structures at higher levels, resulting in a porous composite (P-APC) with high strength (yield strength of 10.5 MPa) and lightweight properties (density below 0.22 g cm-3). Notably, the density-strength property surpasses most reported porous materials. Additionally, P-APC shows ultralow thermal conductivity (45 mW m-1 k-1) due to its porous structure, making its strength and thermal insulation superior to many reported materials. This work provides a robust, lightweight, and thermal insulating composite for practical application. It emphasizes the advantage of prefunctionalization of ionic oligomers for organic-inorganic copolymerization in creating oriented nanostructure with toughened mechanics, offering an alternative strategy to produce robust lightweight materials.

[3D bioprinting: classification, evaluation, and application in vascular tissue engineering].

Cardiovascular diseases are major diseases, and there is lack of artificial blood vessels with small diameters which can be applied in coronary artery bypass surgery. The conventional vascular scaffold preparation techniques in tissue engineering have shortcomings in regulating the diameter, geometric shape, and interconnectivity of the scaffold. 3D bioprinting can simulate the natural structure of the vascular tissue, accurately print live cells and biomaterials, and regulate the microstructure and porosity of scaffolds on the nanoscale, providing new ideas for vascular tissue engineering. This article systematically evaluates the classification of 3D bioprinting technologies and reviews the latest research progress of 3D bioprinting in vascular tissue engineering. It summarizes the advantages of 3D bioprinting and points out the problems that need to be solved, such as the immune rejection of blood vessel materials, providing reference for the further research.