Comparison of microwave and high-pressure processing on bound phenolic composition and antioxidant activities of sorghum hull

The influence of microwave boiling (MB treated 5, 10 and 15 s was abbreviated as MB5, MB10 and MB15, respectively) and high-pressure boiling (HB processed 10, 20 and 30 min was denoted as HB10, HB20 and HB30, respectively) processing on the composition and content of bound phenolic substances of sorghum hull and their antioxidant capacity were evaluated. Nine bound phenolic profiles were identified by HPLC-ESI-MS/MS, including syringic acid, veratric acid, p-hydroxybenzonic acid, caffeic acid, sinapic alcohol, ascorbic acid, prenylnaringenin and luteolin. Compared with traditional hot water processing (HP treated 10, 30 and 50 min was abbreviated as HP10, HP30 and HP50, respectively), the content of free procyanidins and total phenolics of sorghum hull treated with HB increased by 35.92–58.87% and 6.20–18.70%, respectively. Sorghum hull treated with HB20 possessed the highest ABTS (ABTS radical scavenging capacity) and FRAP (ferric ion reducing antioxidant power) among all treatment groups.     

铁氧化物在流化床温度和CO气氛下的形态迁移及其对NO催化还原

利用小型固定床实验台实验研究了铁氧化物在典型流化床温度和CO还原性气氛下的形态迁移及其生成物对NO的催化还原作用，采用分级还原结合X射线衍射（XRD）表征分析，确定铁氧化物与CO和NO反应后生成物的价态及各种铁氧化物对NO的还原机制。结果表明，Fe₂O₃在实验条件下可依次被CO还原为Fe₃O₄、FeO和单质铁，反应过程中随着还原度的增加，还原速率逐级下降，从Fe₂O₃还原到Fe₃O₄的速率最高，FeO还原到Fe速率最低，在实验温度范围内，床温升高有利于提高Fe₂O₃到Fe₃O₄的还原速率和还原度。不同形态的铁氧化物对NO的催化还原特性不同，Fe₂O₃及其部分还原后生成的Fe₃O₄都不能直接与NO反应，Fe₂O₃对CO催化还原NO的效果很弱，而Fe₃O₄对CO还原NO的反应却有很强的催化作用，而进一步还原生成FeO与单质铁还可直接与NO反应。     

Loss cost reduction and power quality improvement with applying robust optimization algorithm for optimum energy storage system placement and capacitor bank allocation

Power losses cause the underutilization of distributed generation (DG) units in addition to the cost increasing in microgrid. Minimizing these losses has been focused in many papers. Using energy storage system (ESS) is a crucial solution for loss reduction. ESS can balance the power exchange in on-peak times where its location and size optimization can improve the microgrid efficiency and reduce the loss cost significantly. Moreover, to ensure the power quality by improving the voltage profile, capacitor bank can be installed optimally on some buses. Optimization of size and location of the capacitor bank can enhance the reactive power that is leading to power loss reduction. In other words, the capacitor bank is applied to compensate the total reactive power and consequently, the current is reduced that results in power loss reduction. In this article, the problem is defined as the optimum location and size of ESS and capacitor bank in the microgrid. Due to the complexity of the problem in many options for selecting the buses to implement these elements (ESS and capacitor bank), robust approach using the particle swarm optimization algorithm and general algebraic modeling system are applied for optimization process. In addition, the uncertainty of renewable DGs such as photovoltaic and wind turbine is modeled by probability density functions and Monte-Carlo is used for selecting more probable cases in optimization processes. The results show the loss cost reduction and improvement in voltage and power profile with less fluctuations and more stability.     

Mn3O4 nanosheets coated on carbon nanotubes as efficient electrocatalysts for oxygen reduction reaction

MnO-MnC_x coated carbon nanotubes (MnO/MnC_x/CNTs) nanocomposites were prepared by a one-pot deposition method. The coating consisted of MnO, Mn₅C₂, Mn₁₅C₄ and Mn₂₃C₆ was formed on the surface of CNTs by heating a mixture of Mn particles and CNTs at 600 °C for 40 min under vacuum. Then after heated MnO/MnC_x/CNTs in air at 350 °C for 2 h, MnO nanoparticles were partially converted to Mn₃O₄ nanosheets. Then Mn₃O₄-MnC_x coated carbon nanotubes (Mn₃O₄/MnC_x/CNTs) composed of interconnected nanosheets structure were successfully synthesized by a two-step method of one-pot deposition and heat post-treatment. The Mn₃O₄/MnC_x/CNTs showed better oxygen reduction reaction performance in alkaline condition than MnO/MnC_x/CNTs and pristine CNTs. Besides, the formed MnC_x (Mn₅C₂ and Mn₂₃C₆) by one-pot deposition method provided a strong interface bonding between Mn₃O₄ and CNTs, leading to improved stability of Mn₃O₄/MnC_x/CNTs as an electrode material.     

Microscopic melanoma detection and classification: A framework of pixel‐based fusion and multilevel features reduction

The numbers of diagnosed patients by melanoma are drastic and contribute more deaths annually among young peoples. An approximately 192,310 new cases of skin cancer are diagnosed in 2019, which shows the importance of automated systems for the diagnosis process. Accordingly, this article presents an automated method for skin lesions detection and recognition using pixel‐based seed segmented images fusion and multilevel features reduction. The proposed method involves four key steps: (a) mean‐based function is implemented and fed input to top‐hat and bottom‐hat filters which later fused for contrast stretching, (b) seed region growing and graph‐cut method‐based lesion segmentation and fused both segmented lesions through pixel‐based fusion, (c) multilevel features such as histogram oriented gradient (HOG), speeded up robust features (SURF), and color are extracted and simple concatenation is performed, and (d) finally variance precise entropy‐based features reduction and classification through SVM via cubic kernel function. Two different experiments are performed for the evaluation of this method. The segmentation performance is evaluated on PH2, ISBI2016, and ISIC2017 with an accuracy of 95.86, 94.79, and 94.92%, respectively. The classification performance is evaluated on PH2 and ISBI2016 dataset with an accuracy of 98.20 and 95.42%, respectively. The results of the proposed automated systems are outstanding as compared to the current techniques reported in state of art, which demonstrate the validity of the proposed method.     

微波耦合铁碳微电解预处理石化废水的试验

采用微波耦合铁碳微电解技术对石化废水进行预处理,并对预处理前后水样中有机物的变化进行分析。结果表明,原水CODCr为10 500 mg/L,在废水pH值为3、铁碳投加量为20%、微波功率为700 W,经微波辐射5 min处理后,出水CODCr为2 370 mg/L左右,COD去除率稳定在77%左右,提高了废水的可生化性。GC-MS和三维荧光分析结果均表明,微波耦合铁碳微电解处理后,试验废水中有机物的数量及浓度大幅降低。结合后续生化处理,可以达到三级污水综合排放标准(GB 8978-1996)。微波耦合铁碳微电解可作为石化废水的有效预处理方法。     

Self-assembled cubic-hexagonal perovskite nanocomposite as intermediate-temperature solid oxide fuel cell cathode

Self-assembly is an emerging strategy for preparing composite cathodes with good oxygen electrochemical reduction activity and congenital chemical compatibility for intermediate-temperature solid oxide fuel cell (IT-SOFC). Here we report that a self-assembled BaCo_0.6Zr_0.4O_3-δ (BZC-BC) nanocomposite is prepared through one-pot glycine-nitrate process and exhibits high cathode performance. The BZC-BC nanocomposite is composed of 62 mol% cubic perovskite BaZr_0.82Co_0.18O_3-δ (BZC) as an ionic conductor and 38 mol% hexagonal perovskite BaCo_0.96Zr_0.04O_2.6+δ (12H-BC) as a mixed ionic and electronic conductor. The BZC-BC nanocomposite has the pomegranate-like particles aggregated with a larger number of nanoparticles (50-100 nm) which greatly enlarge the three-phase boundary sites. The BZC-BC nanocomposite exhibits a thermal expansion coefficient of 12.89 × 10⁻⁶ K⁻¹ well-matched with that of Ce_0.8Gd_0.2O_3-δ (12.84 × 10⁻⁶ K⁻¹) electrolyte. The high electro-catalytic activity of BZC-BC nanocomposite cathode for oxygen reduction is reflected by the low polarization resistances of oxygen ions incorporation at cathode/electrolyte interface (0.02823 Ω cm²), oxygen species diffusion (0.03702 Ω cm²) and oxygen adsorptive dissociation (0.07609 Ω cm²) at 700 °C. The single cell with BZC-BC nanocomposite cathode achieves the maximum power density of 1094 mW cm⁻² at 650 °C and shows good stability under 25 h run.     

Magnetoelectric,magnetodielectric effect and dielectric,magnetic properties of microwave-sintered lead-free x(Co0.9Ni0.1Fe2O4)-(1-x)[0.5(Ba0.7Ca0.3TiO3)-0.5(BaZr0.2Ti0.8O3)] particulate multiferroic composite

Materials with two distinct (magnetostrictive-ferroelectric) phases, i.e., x (Co_0·9Ni_0·1Fe₂O₄) -(1-x) [0.5 (Ba_0·7Ca_0·3TiO₃) −0.5 (BaZr_0·2Ti_0·8O₃)], combined at ratios of 10:90, 20:80, 30:70, and 40:60 were prepared using a hydroxide coprecipitation method. These multiferroic composites were subjected to sintering via the hybrid microwave sintering technique at 1200 °C for 20 min. Ni-substituted CFO exhibited excellent magnetic properties at room temperature, with Ms ≈ 80 emu/g, μB ≈ 3.37, Mr ≈ 19.05 emu/g, and Hc ≈ 599 Oe, as well as a high value of the magnetostriction coefficient (λ12 ≈ −118 ppm). The magnetostrictive-ferroelectric crystal phases in each composite were confirmed via X-ray diffraction analysis. The highest value of the linear magneto-electric coefficient was α = 21.6 mV/cm-Oe at a frequency of 1 kHz for the 40CNFO-60(BCT-BZT) composite, and a similar sample had the highest value of the magnetodielectric coefficient, which was approximately 3.3% at f = 1 kHz with an applied magnetic field of 1 T. The typical ferromagnetic and ferroelectric nature of each composite was confirmed by M − H and P–E hysteresis loops, respectively at room temperature. Two anomalies were observed in the temperature-dependent dielectric permittivity one at ~140 °C and another above 500 °C confirming the coexistence of two materials with distinct transition points, i.e., BCT-BZT and CNFO, respectively.     

锡石多金属硫化矿微波助磨试验研究

本文以广西某选矿厂锡石多金属硫化矿矿石为原料,研究了微波预处理对矿石磨矿产物粒度组成、磨矿动力学、破碎速率及磨机生产能力的影响。结果表明,微波预处理后,矿石在不同磨矿时间下的磨矿产物粒度均变细,-0.074mm粒级含量提高了4.41%~12.90%；微波预处理前后该矿石磨矿均符合一级磨矿动力学模型；微波预处理使矿石的破碎速率(S₁)值提高近57%,且磨机的生产能力得到了明显提升。因此,微波预处理可以降低矿石的强度,强化矿石的磨矿过程,是一种有效的降低磨矿能耗、提高磨矿效率的方法。