Copper substituted nickel ferrite nanoparticles anchored onto the graphene sheets as electrode materials for supercapacitors fabrication

Nickel ferrites with high theoretical capacitance value as compared to the other metal oxides have been applied as electrode material for energy storage devices i.e. batteries and supercapacitors. High tendency towards aggregation and less specific surface area make the metal oxides poor candidate for electrochemical applications. Therefore, the improvements in the electrochemical properties of nickel ferrites (NiFe₂O₄) are required. Here, we report the synthesis of graphene nano-sheets decorated with spherical copper substituted nickel ferrite nanoparticles for supercapacitors electrode fabrication. The copper substituted and unsubstituted NiFe₂O₄ nanoparticles were prepared via wet chemical co-precipitation route. Reduced graphene oxide (rGO) was prepared via well-known Hummer's method. After structural characterization of both ferrite (Ni_1-xCu_xFe₂O₄) nanoparticles and rGO, the ferrite particles were decorated onto the graphene sheets to obtain Ni_1-xCu_xFe₂O₄@rGO nanocomposites. The confirmation of preparation of these nanocomposites was confirmed by scanning electron microscopy (SEM). The electrochemical measurements of nanoparticles and their nanocomposites (Ni_0.9Cu_0.1Fe₂O₄@rGO) confirmed that the nanocomposites due to highly conductive nature and relatively high surface area showed better capacitive behavior as compared to bare nanoparticles. This enhanced electrochemical energy storage properties of nanocomposites were attributed to the graphene and also supported by electrical (I-V) measurements. The cyclic stability experiments results showed ~65% capacitance retention after 1000 cycles. However this retention was enhanced from 65% to 75% for the copper substituted nanoparticles (Ni_0.9Cu_0.1Fe₂O₄) and 65–85% for graphene based composites. All this data suggest that these nanoparticles and their composites can be utilized for supercapacitors electrodes fabrication.     

Thermal properties of cowpea flour: a study by differential scanning calorimetry

The thermal properties of 12 varieties of cowpea flour were studied by differential scanning calorimetry (DSC). Flour samples were prepared to a paste of 60% moisture content and sealed in standard DSC pans. Samples were scanned at a heating rate of 5 degrees C/min over a scan range of 40- 130 degrees C. Samples exhibited single major endotherms, which occurred over varied temperatures. The transition enthalpy (deltaH) ranged between 1.4 J/g and 4.7 J/g. Transition onset (T(o)) and transition peak (T(p)) temperatures ranged between 75-78 degrees C and 78-82 degrees C,respectively. All the DSC parameters measured varied significantly among the varieties. The transition enthalpy (deltaH) was the most discriminating parameter and accounted for 80% of the total variance. The major chemical components of cowpea flour, starch amylose and protein are significant predictors of deltaH. Protein denaturation appears to be a significant modification which occurs during processing of cowpea seeds to flour. The transition enthalpy deltaH could become an important functional index of cowpea flour when related to some quality parameters in products that contain the flour.     

Halogen lamp rapid thermal annealing of Si- and Be-implanted In0.53Ga0.47As

Halogen lamp rapid thermal annealing was used to activate 100 keV Si and 50 keV Be implants in In_0.53Ga_0.47As for doses ranging between 5 × 10¹²−4 × 10¹⁴ cm⁻². Anneals were performed at different temperatures and time durations. Close to one hundred percent activation was obtained for the 4.1 × 10¹³ cm⁻² Si-implant, using an 850° C/5 s anneal. Si in-diffusion was not observed for the rapid thermal annealing temperatures and times used in this study. For the 5 × 10¹³ cm⁻² Be-implant, a maximum activation of 56% was measured. Be-implant depth profiles matched closely with gaussian profiles predicted by LSS theory for the 800° C/5 s anneals. Peak carrier concentrations of 1.7 × 10¹⁹ and 4 × 10¹⁸ cm⁻³ were achieved for the 4 × 10¹⁴ cm⁻² Si and Be implants, respectively. For comparison, furnace anneals were also performed for all doses.     

白藜芦醇潜在的有益健康作用：药代动力学带来的困惑

白藜芦醇（Resveratrol,3,5,4'-三羟基-反式-二苯乙烯）最早在植物白藜芦（Veratrum grandiflorum O. Loes）的根中被发现。白藜芦醇引起关注最初与“法国悖论”有关,该化合物不仅存在于红葡萄酒中,而且还展现出与红葡萄酒保护心血管作用相关的生物活性。除保护心血管方面的作用外,白藜芦醇还在抗代谢性疾病、抗肿瘤和预防神经退行性疾病等方面表现出有益的作用。为了将这些潜在的有益健康作用向临床转化,人们对白藜芦醇开展了药代研究。本文作者从进入体循环的系统暴露和体内过程两个方面,总结了目前已知的口服后白藜芦醇的人体药代特征及围绕提高其系统暴露水平所做的多种尝试。然而,既有的药代动力学结果给白藜芦醇潜在作用的临床转化带来了困惑,包括：白藜芦醇展现有益健康的体外生物活性的物质形式（原形化合物）与口服后被机体利用的体内暴露形式（以代谢物为主）显著不同、药代研究测出的口服后白藜芦醇体内暴露水平明显低于其展现活性所需的浓度、根据白藜芦醇产生体内效应时所用的剂量推导出的体内暴露水平常明显低于研究其作用机制所用的浓度。为了更好地与白藜芦醇有益健康作用的研究相结合、促进其临床转化,作者建议从三方面进一步开展白藜芦醇的药代研究：（1）全面研究白藜芦醇代谢物的系统暴露、体内靶标到达及在靶细胞中的代谢,（2）研究口服后白藜芦醇的肠腔暴露,（3）开展红葡萄酒多成分药代研究。     

Chemical,phase and structural change of mullite synthesized during sintering of kaolin

Mullite is of great technological relevance but rarely occurs in nature and as a result different approaches have been adopted in its synthesis from alumina bearing minerals. In this study, chemical, phase and structural change of mullite synthesized from sintering of natural kaolinite clay is investigated. Thoroughly beneficiated kaolinite clay powder was obtained from Nigeria and uniaxially pressed into cylindrical compact of 40 × 30 mm followed by sintering at temperatures of 1200°C and 1300°C, respectively. The chemical composition, microstructure change, phase transformation, and reaction bonding were carried out using EDXRF, SEM, XRD, and FT-IR, respectively, to assess the synthesized mullite. The results showed that a well-dispersed primary mullite phase was obtained which was fully developed at increased temperature of 1300°C. Better mullite phase was also obtained with increasing alumina content at more elevated temperature of 1300°C while Si-O-Al bonding of mullite crystals was also obtained from the FT-IR spectra. However, the needle-shaped mullite structure was not achieved which might be attributed to the sintering temperatures 1200°C-1300°C utilized.     

Analysing wear behaviour of Al–CaCO3 composites using ANN and Sugeno-type fuzzy inference systems

Neural Computing and Applications - Design of experiment for the development of stir cast calcium carbonate-reinforced aluminium composite is a search for optimum combination of material and...