Zinc oxide nanoparticles loaded active packaging,a challenge study against Salmonella typhimurium and Staphylococcus aureus in ready-to-eat poultry meat

Zinc oxide nanoparticles were prepared using hydrothermal synthesis approach. Formation of zinc oxide nanoparticles were confirmed by using UV–Vis spectrophotometer, Fourier transform infrared spectrometer and X-ray diffractometer. The particles size (≤100 nm) and structure of nanoparticles were studied under scanning and transmission electron microscope. The nanoparticles were used against two prominent foodborne pathogens, Salmonella typhimurium and Staphylococcus aureus and were found highly effective against both of them. The antibacterial activity of the nanoparticles was determined in solid and liquid media using nutrient agar and broth. Zinc oxide nanoparticles loaded active film of calcium alginate was prepared for active packaging against the same foodborne pathogens (S. typhimurium and S. aureus). Presence and distribution of nanoparticles in active film were confirmed with Fourier transform infrared spectrometer, X-ray diffractometer and scanning electron microscopy. Zinc oxide nanoparticles loaded active films showed antibacterial activity against the target bacteria in Petri dish. The film was also used as an active packaging (a challenge study) in ready-to-eat poultry meat against the same pathogens, and reduced the number of inoculated target bacteria from log seven to zero within 10 days of its incubation at 8 ± 1 °C.     

Enhanced densification of thin tape cast Ceria-Gadolinium Oxide (CGO) layers by rheological optimization of slurries

Optimized CGO-based slurries are formulated and shaped into thin dense layers via a tape-casting process. The formulation is adjusted with respect to the rheological behaviour. The internal structure and flow properties of slurries are explored with the aim of identifying the required conditions to obtain thin dense CGO layers at reduced sintering temperatures (1200 °C). We demonstrate a correlation between the rheological properties of the slurries, the sintering behaviour and the microstructure of the resulting tapes. Remarkably, a dense CGO layer less than 20 µm thick is obtained with a non-congested slurry, having optimized ceramic loading and liquid-like behaviour.     

氧化铜（CuO）作催化剂测定废水化学需氧量(CODCr)试验

以CuO作为替代催化剂体系,协同硫磷混酸介质,探讨了无银催化法测定污水中化学需氧量(COD)的系列条件试验。结果表明测定最佳条件为CuO以粉末形式投加,投加量为0.05 g、硫酸∶磷酸(体积比)为5∶1、消解温度控制在160℃、消解时间为2 h,准确度、精密度与国标法有较好的可比性,其相对标准偏差为0.40%-0.58%。在实际废水测定中,与国标法测定结果比较,加标回收率为97.0%-103.3%。该方法完全可以成为常规实验室的适用方法。     

Peptide‐functionalized reduced graphene oxide as a bioactive mechanically robust tissue regeneration scaffold

Bioactive, synthetic materials represent next‐generation composites for tissue regeneration. Design of contemporary materials attempts to recapitulate the complexities of native tissue; however, few successfully mimic the order in nature. Recently, graphene oxide (GO ) has emerged as a scaffold due to its potential for bioactive functionalization and long‐range order instilled by the self‐assembly of graphene sheets. Chemical reduction of GO results in a more compatible material with enhanced properties but compromises the ability to functionalize the graphenic backbone. However, using Johnson–Claisen rearrangement chemistry, functionalization is achieved that is not liable to reduction. From reduced Claisen graphene, we polymerized short homopeptides from α ‐amino acid N ‐carboxyanhydride monomers of glutamate and lysine to result in functionalized graphenes (pGlu‐rCG and pLys‐rCG ) that are cytocompatible, degradable, and bioactive. Exposure to NIH‐3T3 fibroblasts and RAW 264.7 macrophages revealed that the materials are cytocompatible and do not alter important sub‐cellular compartments. Powders were hot pressed to form mechanically stiff (E ′: 41 and 49 MPa ), strong (UCS : 480 and 140 MPa ), and tough (U _T: 2898 and 584 J m^?3 × 10⁴) three‐dimensional constructs (pGlu‐rCG and pLys‐rCG, respectively). Overall, we report a robust chemistry and processing strategy for facile bioactive functionalization of compatible, reduced Claisen graphene for three‐dimensional biomedical applications. © 2017 Society of Chemical Industry     

Metallic interconnects for solid oxide fuel cell: A review on protective coating and deposition techniques

With the reduction of solid oxide fuel cells (SOFCs) operating temperature to the range of 600 °C–800 °C, metallic alloy with high oxidation resistance are used to replace traditional ceramic interconnects. Metallic interconnects is advantageous over ceramic interconnects; in terms of manufacturability, cost, mechanical strength, and electrical conductivity. To date, promising candidates for metallic interconnects are all Cr-containing alloys, which are susceptible to volatile Cr migration that causes cell degradation. As such, protective coatings have been developed to effectively inhibit Cr migration; as well as maintain excellent electrical conductivity and good oxidation resistance. This article reviews the progress and technical challenges in developing metallic interconnects; different types of protective coatings and deposition techniques for metallic interconnects for intermediate-temperature SOFC applications.     

Effects of temperature and pressure in oxynitridation kinetics on Si(100) with N2O gas

We have investigated oxynitridation of Si(100) surfaces with nitrous oxide (N₂O) gas in a wide range of substrate temperatures (600–1000 °C) and N₂O pressures (10⁻²–10² Pa). The growth rate and atomic composition of the oxynitride layer have been measured by in situ x-ray photoelectron spectroscopy. The surface morphology of the oxynitride layer has been also observed by scanning electron microscopy. The results show that in higher N₂O pressure (>1 Pa) regime, the nitridation reaction is suppressed by the oxide layer, which quickly forms on the surface. On the other hand, in lower pressure (<1 Pa) and higher substrate temperature (>900 °C) regime, the nitridation reaction strongly occurs because of the active oxidation (etching reaction), which causes the surface roughness. It is found by argon-ion-sputtering measurements that the nitride layer locally exists only near the surface at the reduced N₂O pressure. We discuss qualitatively the oxynitridation kinetics and the effective condition for growing the oxynitride layer.     

Investigation of the electrochemical active thickness of solid oxide fuel cell anode

Determination of the electrochemical active thickness (EAT) is of paramount importance for optimizing the solid oxide fuel cell (SOFC) electrode. However, very different EAT values are reported in the previous literatures. This paper aims to systematically study the EAT of SOFC anode numerically. An SOFC model coupling electrochemical reactions with transport of gas, electron and ion is developed. The microstructure features of the electrode are modeled based on the percolation theory and coordinate number theory. Parametric analysis is performed to examine the effects of various operating conditions and microstructures on EAT. Results indicate that EAT increases with decreasing exchange current density (or decreasing TPB length) and increasing effective ionic conductivity. In addition to the numerical simulations, theoretical analysis is conducted including various losses in the electrode, which clearly shows that the EAT highly depends on the ratio of concentration related activation loss R_act,con to ohmic loss R_ohmic. The theoretical analysis explains very well the different EATs reported in the literature and is different from the common understanding that the EAT is controlled mainly by the ionic conductivity of electrode.     

Co/CuO–NiO–Al2O3 catalyst for hydrogen generation from hydrolysis of NaBH4

This paper presents hydrogen generation measurements from the hydrolysis of NaBH₄ aqueous solutions catalyzed by Co doping on single, bimetallic and trimetallic oxide supports (Co/CuO, Co/NiO, Co/Al₂O₃, Co/NiO–Al₂O₃, Co/CuO–Al₂O_3, and Co/CuO–NiO–Al₂O₃). Support materials are synthesized by the co-precipitation method. Then, Co is doped into support materials by the impregnation method. It is found that Co/CuO–NiO–Al₂O₃ catalyst exhibited high reaction activity with a maximum hydrogen generation rate (HGR) of 2067.2 ml min^?1 g_cat^?1 at 25 °C. The effect of temperature of the solution, Co amount, and recyclability of the catalyst on hydrogen generation with Co/CuO–NiO–Al₂O₃ catalyst is investigated in detail. In addition, the highest HGR for Co/CuO–NiO–Al₂O₃ catalyst is obtained at 55 °C as 6460.0 ml min^?1 g_cat^?1. The activation energy is calculated to be 31.59 kJ mol^?1 using Co/CuO–NiO–Al₂O₃ catalyst. Co/CuO–NiO–Al₂O₃ catalyst exhibits zero-order reaction kinetics concerning NaBH₄ concentration. In addition, the Co/CuO–NiO–Al₂O₃ catalyst provided high reusability after 5 cycles.     

Effect of air addition to the air electrode on the stability and efficiency of carbon dioxide electrolysis by solid oxide cells

In this study, the effect of air addition to the air electrode on the long-term stability and efficiency of solid oxide cells for CO₂ electrolysis, with 23.8% CO as protective gas in the fuel electrode, has been investigated. The results show that without continuous purging of the air in the air electrode (Cell-1), the degradation rate was 8.37%/kh in the 1070 h electrolysis process, while with 5 L/min air supplied to the air electrode (Cell-2), the degradation rate was 24.41%/kh. Impedance analysis indicates that the degradation of Cell-1 was mainly because of the increase in O^2? exchange polarization impedance, while the degradation of Cell-2 was caused mainly by the variation of ohmic impedance. The microstructural characterization indicated a decrease in active Ni in the fuel electrode in both Cell-1 and Cell-2, but the degree of nickel loss depended on the test time. At the outlet of the Cell-2, the appearance of carbon further explains the faster degradation rate, although the carbon deposition was not directly caused by the introduction of air into the air electrode. Energy spectral analysis shows that the air electrode in Cell-1 generated Sr rich phases, which indicates that the absence of air in the air electrode in the electrolysis process indeed causes more serious microstructure damage. The energy conversion efficiency could exceed 86% if the energy consumed for heating the air is ignored. This work provides a scenario for the application of solid oxide cells for CO₂ electrolysis without air purging in the air electrode.