应用需盐脱硫弧菌的微生物燃料电池发电研究

本文提出了基于需盐脱硫弧菌以含乳酸盐的海水培养基为电解液的微生物燃料电池.微生物接种后电池即开始放电,在20天中,培养基COD降低了61.7%,其中有9.81%转化为电能.     

Cellulose nanofibrils—adsorption with poly(amideamine) epichlorohydrin studied by QCM-D and application as a paper strength additive

In this paper cellulose nanofibrils were used together with a cationic polylelectrolyte, poly(amideamine) epichlorohydrin (PAE), to enhance the wet and the dry strength of paper. The adsorption of nanofibrils and PAE on cellulose model surfaces was studied using quartz crystal microbalance with dissipation (QCM-D) and atomic force microscopy (AFM). The differences in fibril and polyelectrolyte adding strategies onto cellulose fibres were studied by comparing layer-structures and nano-aggregates formed by the nanofibrils and PAE. The results showed that when PAE was first adsorbed on the model fibre surface a uniform and viscous layer of nanofibrils could be adsorbed. When PAE and nanofibrils were adsorbed as cationic aggregates a non-uniform and more rigid layer was adsorbed. Paper sheets were prepared using both the bi-layer and nano-aggregate adding strategy of the nanofibrils and PAE. When PAE and nanofibrils were adsorbed on pulp fibres as a bi-layer system significant increase in both wet and dry tensile strength of paper could be achieved even at low added amounts of PAE. When the substances were added as nano-aggregates the improvements in paper strength properties were not as significant. Bulk and surface nitrogen content analyses of the paper samples showed that the adding strategy does not affect the total adsorbed amount of PAE but it has a strong effect on distribution of substances in the paper matrix which has a crucial effect on paper wet and dry strength development.     

Water‐in‐oil Emulsions Stabilized by Hydrophobized Microfibrillated Cellulose

The properties of water‐in‐toluene emulsions stabilized solely by hydrophobized microfibrillated cellulose (MFC) were investigated. By varying the degree of surface substitution (DSS), the wettability of the MFC was altered. All emulsions prepared with MFC displayed excellent stability to coalescence. The stability to gravity‐induced sedimentation increased with increasing MFC concentration, the highest stability being obtained with MFC of moderate hydrophobicity. Drop sizes increased with increasing DSS, with a corresponding decrease in stability to sedimentation. An increase in the toluene:water ratio at constant MFC concentration resulted in a decrease in the average drop size. For all emulsions, the polydispersity in drop size decreased with decreasing average drop diameter.     

基于机电阻抗技术的管道法兰结构健康监测实验研究

基于机电阻抗技术,采用一种新型压电陶瓷纤维复合材料MFC(Macro-fiber composite),对管道连接处法兰的螺栓工况进行监测实验研究。首先,研究了螺栓扭矩大小对管道法兰结构的阻抗的影响程度。在对螺栓开始施加扭矩时阻抗值变化明显,当扭矩增大到一定程度后,阻抗变化减缓。同时进一步研究了松动螺栓数量与管道法兰结构的阻抗变化之间的关系。结果显示,结构的损伤值随松动螺栓个数的增加呈线性增长。采用均方根偏差统计算法,对在不同工况条件下管道法兰结构处测得的阻抗值进行了有效的分析和处理。结果表明,采用MFC作为压电敏感元件的机电阻抗法,用于管道法兰结构健康监测具有较好的稳定性和应用潜力。     

EXPERIMENTAL AND NUMERICAL STUDIES ON PERFORMANCE OF MACRO FIBER COMPOSITES FOR BEAM TWISTING APPLICATIONS

This paper presents the use of macro-fiber composites (MFC) as actuators for twisting control of pre-twisted beams, which is one efficient method of vibration suppression techniques of helicopter rotors. An MFC is a piezoelectric fiber composite which has an interdigitated electrode, rectangular cross-section and unidirectional piezoceramic (PZT) fibers embedded in the polymer matrix. An MFC actuator has much higher actuation performance, flexibility and durability than a traditional piezoceramic (PZT) actuator. This study showed that an MFC could be used as an actuator to change the displacement and twist tip-angle of a pre-twisted beam. In the test, an MFC patch was pasted on the beam’s upper surface to twist the pre-twisted beam actively. Different twist tip-angle changes of the pre-twisted beam were measured under a series of actuation voltages, and a good agreement was observed when experimental results were compared with numerical results. In addition, the actuation performance of MFC was compared with those of PZT4 and PVDF and the influence of anisotropic property of the MFC on its actuation performance was also studied. The experimental and numerical results presented in this paper show the potential of MFC for use in the vibration control of helicopter rotors.