Catalytic Hydrothermal Liquefaction of Water Hyacinth Using Fe3O4/NiO Nanocomposite: Optimization of Reaction Conditions by Response Surface Methodology

This research aimed at optimizing the reaction conditions for the catalytic hydrothermal liquefaction (HTL) of water hyacinth using iron oxide/nickel oxide nanocomposite as catalysts. The iron oxide/nickel oxide nanocomposite was synthesized by the co-precipitation method and used in the hydrothermal liquefaction of water hyacinth. The composition and structural morphology of the synthesized catalysts were determined using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic absorption spectroscopy (AAS). The particle size distribution of the catalyst nanoparticles was determined by the Image J software. Three reaction parameters were optimized using the response surface methodology (RSM). These were: temperature, residence time, and catalyst dosage. A maximum bio-oil yield of 59.4 wt% was obtained using iron oxide/nickel oxide nanocomposite compared to 50.7 wt% obtained in absence of the catalyst. The maximum bio-oil yield was obtained at a temperature of 320°C, 1.5 g of catalyst dosage, and 60 min of residence time. The composition of bio-oil was analyzed using gas chromatography-mass spectroscopy (GC-MS) and elemental analysis. The GC-MS results showed an increase of hydrocarbons from 58.3% for uncatalyzed hydrothermal liquefaction to 88.66% using iron oxide/nickel oxide nanocomposite. Elemental analysis results revealed an increase in the hydrogen and carbon content and a reduction in the Nitrogen, Oxygen, and Sulphur content of the bio-oil during catalytic HTL compared to HTL in absence of catalyst nanoparticles. The high heating value increased from 33.5 MJ/Kg for uncatalyzed hydrothermal liquefaction to 38.6 MJ/Kg during the catalytic HTL. The catalyst nanoparticles were recovered from the solid residue by sonication and magnetic separation and recycled. The recycled catalyst nanoparticles were still efficient as hydrothermal liquefaction (HTL) catalysts and were recycled four times. The application of iron oxide/ nickel oxide nanocomposites in the HTL of water hyacinth increases the yield of bio-oil and improves its quality by reducing hetero atoms thus increasing its energy performance as fuel. Iron oxide/nickel oxide nanocomposites used in this study are widely available and can be easily recovered magnetically and recycled. This will potentially lead to an economical, environmentally friendly, and sustainable way of converting biomass into biofuel.

A new model for film bulk acoustic wave resonators

Based on cavity resonance and sandwich composite plate （3D） theoretical model for frequency dispersion characterization theory, this paper presents a universal three-dimensional and displacement profile shapes of the film bulk acoustic resonator （FBARs）. This model provides results of FBAR excited thickness-extensional and flexure modes, and the result of frequency dispersion is proposed in which the thicknesses and impedance of the electrodes and the piezoelectric material are taken into consideration; its further simplification shows good agreement with the modified Butterworth-Van-Dyke （MBVD） model. The displacement profile reflects the vibration stress distribution of electrode shapes and the lateral resonance effect, which depends on the axis ratio of the electrode shapes a/b. The results are consistent with the 3D finite element method modeling and laser interferometry measurement in general.

A New Radio Access Scheme for Co-operation Networks in B3G Wireless Communications

The paper discusses the signifi cance and development foreground of co-operation among heterogeneous networks in composite radio context for B3G wireless communications. The concept of composite reconfigurable wireless network is introduced in the paper, and the development of future wireless communication systems is also discussed. The basic confi guration framework of the network interoperation is given, and the functions of important parts are analyzed. A management platform for co-operation between WLAN and cellular network is introduced, adding several models to the original systems. Furthermore, new radio access schemes for different types of Mobile Terminals (MTs) are proposed. Particularly, Spectrum Sharing (SS) between WLAN and cellular networks is discussed. Here, a new radio access scheme and channel assignment mechanism with code-division duplex (CDD) and Frequency Hopping (FH) technologies are raised, for the purpose of avoiding interference between heterogeneous networks. Finally, the performance of the above radio access schemes is analyzed, and simulation results proved its validation.

Relationship Between Electric Properties and Temperature of ZrB_2-SiC Composite Ceramic Heating Element

ZrB2 -SiC composite ceramic has been successfully introduced as heating element in super high temperature .field. This paper further investigated the microstructure of ZrB2 - SiC composite ceramic heating element and the relationship between electric properties and temperature. SEM photos show that the heating element consists of SiC grains and ZrBz grains smaller than 10 μm. The voltage and current gradually increase and the furnace tempera- ture rises lineally with heating time prolonging. The electric resistance increases linearly with the temperature rising. The service temperatltre of the heating element can reach 1 800 ℃ and 2 150 ℃ in air and argon at- mosphere, respectively.

设计模式在软件设计中的应用

本文介绍了什么是设计模式，说明应用设计模式的优点，并用Observer、Com-posite、Strategy、Abstract Factory四个模式具体讨论了设计模式在软件设计中的应用。

持续释放蒙脱土插层杂化复合材料中的成骨微量元素促进骨再生

优化支架组分和结构以实现内源性成骨是骨组织工程中一项有前景的进展.本研究将蒙脱土作为一种增强相,以插层结构引入到多巴胺介导的仿生有机/无机杂化水凝胶中.通过蒙脱土-聚合物相互作用和多酚介导的多重反应改善了骨再生支架(HDC-HAp-MMT)的理化特性,增强了力学性能和抗降解能力.特别是,持续性释放的有益微量元素为成骨微环境提供了关键的成骨生化信号.该水凝胶在体外促进了骨髓间充质干细胞增殖和成骨分化.同时,在异位成骨模型中,显著增强了矿物沉积(30天后机械增强6.91倍);在原位兔颅骨修复实验中,实现了相对于天然骨80.94%的骨体积分数和85.89%的骨密度.该策略可能代表了一种新型的生物活性骨再生支架的制备方法.

Thermal transport in organic/inorganic composites

Composite materials, which consist of organic and inorganic components, are widely used in various fields because of their excellent mechanical properties, resistance to corrosion, low-cost fabrication, etc. Thermal properties of organic/inorganic composites play a crucial role in some applications such as thermal interface materials for micro-electronic packaging, nano-porous materials for sensor development, thermal insulators for aerospace, and high-performance thermoelectric materials for power generation and refrigeration. In the past few years, many studies have been conducted to reveal the physical mechanism of thermal transport in organic/ inorganic composite materials in order to stimulate their practical applications. In this paper, the theoretical and experimental progresses in this field are reviewed. Besides, main factors affecting the thermal conductivity of organic/ inorganic compositcs are discussed, including the intrinsic properties of organic matrix and inorganic fillers, topolo- gical structure of composites, loading volume fraction, and the interfacial thermal resistance between fillers and organic matrix.