Effect of bacterial cellulose nanofibers incorporation on acid-induced casein gels: microstructures and rheological properties

In this study, the effect of bacterial cellulose nanofibers (BCNF) incorporation on the structural and rheological properties of casein gels was investigated, where the mixed BCNF and casein gels were prepared by adding gluconic acid δ-lactone (GDL) to acidify the mixed polymer solutions at 3.0% casein concentration (w/v) and varying BCNF concentrations (0–0.5%, w/v). By changing the addition amount of GDL, the mechanical and structural properties of the mixed gels were studied at above, near and below the electric point (pI) of the casein. At pH above the pI of the casein, the introduction of BCNF initially increased the gel strength, but further addition of BCNF weakened the mixed gels. At near and below the pI of the casein, the incorporation of BCNF continuously increased the gel strength. Besides, all gels showed good structural homogeneity, without macroscopic phase separation occurring, which indicated good compatibility of BCNF with the casein gels.

Effects of Plotytarya strohilacea Sieb. et Zuce Tannin on the Growth Performance, Oxidation Resistance, Intestinal Morphology and Cecal Microbial Composition of Broilers

The purpose of this experiment was to study the effects of Plotytarya strohilacea Sieb. et Zuce tannin on broilers growth performance, antioxidant function, intestinal development, intestinal morphology and the cecal microbial composition. In this experiment, a total of 360 1-day-old Arbor Acres male broilers were randomly divided into 4 treatment groups, with 6 replicates in each group and 15 broilers in each replicate. The control group (Control) was fed the basal diet, and the broilers were fed a basal diet supplemented with 0 (Control), 100 (PT1), 400 (PT2), and 800 (PT3) mg/kg Plotytarya strohilacea Sieb. et Zuce tannins for 42 days, respectively. The results showed that the average daily feed intake (ADFI) of the PT1 group was significantly lower than that of the control group, and there was a significant quadratic relationship between the ADFI and the concentration of tannin (P < 0.05). Compared with the control group, the F/G of broilers during the 22–42 days phase in the PT1 group showed a decreasing trend (P = 0.063). The serum catalase (CAT) activity in the PT1 group was significantly higher than those of the other three groups, and the effect was significantly quadratically related to the dosage (P < 0.05). The glutathione peroxidase (GSH-Px) activity in the PT1, PT2 and control groups were significantly higher than that of the PT3 group, and the effect was significantly quadratically related to the addition amount (P < 0.05). The serum total antioxidant capacity (T-AOC) activity in the PT1 group was significantly higher than that in the control group, and the effect was significantly quadratically related to the addition amount (P < 0.05). Compared to the control group, the villus height of jejunum in the PT1, PT2 and PT3 groups were significantly higher, and there was a significant quadratic relationship between the villus height of jejunum and the addition amount (P < 0.05). In addition, adding tannins to diets significantly increased Parabacteroides in the dominant genus (P < 0.05). In conclusion, dietary supplementation with Plotytarya strohilacea Sieb. et Zuce tannin improved the growth performance, antioxidant function, and intestinal morphology along with an increased abundance of Parabacteroides in the cecum, and the recommended dosage of tannin in broiler diets was 100 mg/kg.

Effective Dehydration of Fructose Over Stable Ti-Doped SBA-15 Catalysts

High-effective synthesis of 5-hydroxymethylfurfural (HMF) from carbohydrates is an interesting reaction among biomass valorization. The as-synthesized Ti-SBA-15 catalysts with mesoporous structures showed high catalytic efficiency for the conversion of fructose to HMF. Ti-SBA-15 catalysts with different Si/Ti ratios were characterized by characterization techniques such as elemental analysis, XRD, TEM, N2 adsorption–desorption, NH3-TPD, and pyridine-FTIR. The acidity of Ti-SBA-15 catalysts could be tuned by altering addition amount of titanium. The effects of reaction conditions, including reaction time, temperature, and amount of catalyst, on the conversions of fructose and the yields of HMF were also investigated. It is found that Ti-SBA-15 catalysts whose Si/Ti ratio is 120 gave the best yields of HMF, which demonstrated 100% conversion of fructose with a maximum HMF yield of 82% at 140°C after 1 h. In addition, its catalytic performance was retained after 5 recycles in fructose conversion reaction, proving its good catalytic stability.

Preparation of Melamine/Rice Husk Powder Coated Shellac Microcapsules and Effect of Different Rice Husk Powder Content in Wall Material on Properties of Wood Waterborne Primer

The melamine/rice husk powder-coated shellac microcapsules were prepared by in-situ polymerization with melamine resin mixed with rice husk powder as microcapsule wall material and shellac as microcapsule core material. The effect of the addition amount of microcapsules with different wall material ratios on the performance of wood waterborne primer coating was investigated. The results show that the most important factor affecting the performance of microcapsules is the content of rice husk powder. Through the preparation and analysis of shellac microcapsule primer coating coated with melamine/rice husk powder, when the content of microcapsule powder is 0–6%, it has little effect on the optical properties of wood waterborne primer coating, and the microcapsule with 5.5% rice husk powder has little effect on the color difference of primer coating. The coating hardness increases with the increase of rice husk powder content in wall material. When the rice husk powder content in wall material is more than 5.5%, the coating hardness reaches the best. When the content of microcapsule powder is 3.0–9.0%, the adhesion of the coating is better, and the coating with rice husk powder content of 5.5% in microcapsule wall material has better impact resistance. When the content of rice husk powder was 5.5% and the content of microcapsule powder was 6%, the elongation at break of the primer coating was the highest and the tensile resistance was the best. The composition of wood waterborne primer did not change after adding microcapsule. The water-based primer with microcapsule has better aging resistance. The water-based primer coating with rice husk powder content of 5.5% and the addition amount of 6% had the best comprehensive performance, which lays the technical reference for the toughness and self-repairing of the waterborne wood coatings.

Mechanism of Oxytetracycline Removal by Coconut Shell Biochar Loaded with Nano-Zero-Valent Iron

In this paper, coconut shell biochar (BC), pickling biochar (HBC), and nano-zero-valent iron-loaded biochar (nZVI-HBC) were prepared; these were used to remove oxytetracycline (OTC), and the removal mechanism and degradation product were analyzed. These biochars were characterized using SEM, XRD, FTIR, and XPS. The effects of biochar addition amount, pH, ion type, and ion concentration on OTC adsorption were studied by a batch adsorption experiment. Under the optimal conditions, the equilibrium adsorption capacity of nZVI-HBC to OTC was 196.70 mg·g−1. The adsorption process can be described by Langmuir isothermal adsorption equations, conforming to the pseudo-second-order dynamics model, indicating that adsorption is dominated by single-molecule chemical adsorption, and a spontaneous process of increasing heat absorption entropy. Mass spectrometry showed that the OTC removal process of nZVI-HBC included not only adsorption but also degradation. These results provide a practical and potentially valuable material for the removal of OTC.

Influence of cerium content on the microstructure and thermal expansion properties of suction cast Al-Cu-Fe alloys

Low-expansion alloys are of great importance and can be used for the development of new aerospace materials. Herein, we report diverse rare earth quasicrystal alloys fabricated by the vacuum suction casting process. The effects of the addition of cerium (Ce) on the microstructure, thermal expansion properties and microhardness of the Al-Cu-Fe alloy were systematically investigated. This study discovered the tiny Al-Cu-Fe-Ce microstructure. A uniform distribution could be achieved after Ce addition amount is elevated. At the Ce addition amount of 1 at%, the lowest alloy thermal expansion coefficient was obtained. The alloy exhibited the maximum microhardness under these conditions. The microhardness of alloys containing 1 at% of Ce was approximately 2.4 times higher than the microhardness exhibited by alloys devoid of Ce additives. The coefficient of thermal expansion decreases by approximately 20%. The use of the suction casting process and the addition of an appropriate amount of Ce can potentially help design and develop Al-Cu-Fe-Ce alloys.

Crystallization and Dielectric Properties of BaO-SrO-PbO-TiO2-Nb2O5-SiO2 Glass-Ceramic Composites with La2O3 Addition

Glass-ceramic composite samples with different La2O3 content were prepared via melt-quenching followed by controlled crystallization. X-ray diffraction(XRD) analysis reveals that when the addition amount of La2O3 in the glass sample is less than 1mol%, two phases of perovskite structure and tungsten-bronze structure are formed after annealing at 1000°C for 3h. When the addition amount of La2O3 in the glass sample is increased to 2mol%, a new phase of pyrochlore structure is formed. Moreover, the addition of La2O3 causes the change in the lattice parameters of the glass-ceramic crystal phase. The microstructure observed that the ceramic phase grain size is in the nanometer level. The shape of some grains becomes an elongated structure when the La2O3 content in the sample increases to 2 mol%, and the grain size is increased significantly. The dielectric constant of the BaO-SrO-PbO-TiO2-Nb2O5-SiO2 glass-ceramic system is decreased with the increase of La2O3 addition, and the dielectric loss of the sample is decreased to the range of 0.003-0.008. The electric field stability of the dielectric constant was significantly improved with the addition of La2O3, indicating that adding a certain proportion of La2O3 to the BaO-SrO-PbO-TiO2-Nb2O5-SiO2 glass-ceramic system can effectively improve the dielectric properties, and it has a promising application as a dielectric material.

Research on Percolation Threshold of Broadband Electromagnetic Wave Absorbing SiCN (MWCNTs) Composite Ceramics

A simple polymer derivation method was applied in this paper to prepare a series of SiCN (MWCNTs) composite ceramics by adjusting the mass ratio of multi-walled carbon nanotubes (MWCNTs). The percolation threshold of the corresponding MWCNTs addition amount when SiCN(MWCNTs) composite ceramics exhibit the optimal electromagnetic wave (EWM) absorption performance was studied, the effect of different addition amounts of MWCNTs on reflection loss (RL), effective absorption bandwidth (EAB), electromagnetic parameters, impedance matching parameters (Z) and attenuation coefficient (α) of composite ceramics was analyzed, and the EMW absorption mechanism of the corresponding composite ceramics when MWCNTs addition amount fix at percolation threshold was discussed. The results showed that composite ceramics exhibited the best EMW absorption performance when the addition amount of MWCNTs reached the percolation threshold (10wt%): the minimum reflection loss (RLmin) was -37.9 dB, and the EAB was 2.8 GHz at a thickness of 2.4 mm; its RLmin was -21.7 dB, and the EAB reached 4.7 GHz at a thickness of 1.7 mm. By changing the sample thickness from 1.0 mm to 5.0 mm, the EAB containing the C, X and Ku bands can be acquired. Therefore, it is expected to be a promising candidate for the new generation of EMW absorbers due to its light weight, high efficiency and broad band.

Compositional Engineering of FAPbI3 Perovskite Added MACl with MAPbBr3 or FAPbBr3

Many attempts have been made to stabilize α-phase formamidinium lead iodide (α-FAPbI3) using mixed cations or anions with MA+, FA+, Br− and I−. A representative method is to stably produce α-FAPbI3 by adding methylammonium lead (MAPbBr3) to the light absorption layer of a perovskite solar cell and using methylammonium chloride (MACl) as an additive. However, in the perovskite containing MA+ and Br−, the current density is lowered due to an unwanted increase in the bandgap; phase separation occurs due to the mixing of halides, and thermal stability is lowered. Therefore, in this study, in order to minimize the decrease in the composition ratio of FAPbI3 and to reduce MA+, the addition amount of MACl was first optimized. Thereafter, a new attempt was made to fabricate FAPbI3 perovskite by using formamidinium lead bromide (FAPbBr3) and MACl together as phase stabilizers instead of MAPbBr3. As for the FAPbI3-MAPbBr3 solar cell, the (FAPbI3)0.93(MAPbBr3)0.07 device showed the highest efficiency. On the other hand, in the case of the FAPbI3-FAPbBr3 solar cell, the (FAPbI3)0.99(FAPbBr3)0.01 solar cell with a very small FAPbBr3 composition ratio showed the highest efficiency with fast photovoltaic performance improvement and high crystallinity. In addition, the FAPbI3-FAPbBr3 solar cell showed a higher performance than the FAPbI3-MAPbBr3 solar cell, suggesting that FAPbBr3 can sufficiently replace MAPbBr3.