Anodic Performance of BaO-Added Ni/SDC for Solid Oxide Fuel Cell Fed With Dry CH4

SOFCs fed with dry H2 and CH4 fuels were examined using 20 wt% Ni/SDC and 0.2 wt% BaO-added 20 wt% Ni/SDC [Ni(BaO)/SDC] anodes. The i–v characteristics of the cells in H2 and CH4 resulted in a higher output produced by CH4 fuel compared to that produced by H2 fuel in both anodes. In both fuels, better anode characteristics were obtained for Ni(BaO)/SDC. Consequently, the anodic performance was in the order of Ni(BaO)/SDC in CH4 > Ni/SDC in CH4 > Ni(BaO)/SDC in H2 > Ni/SDC in H2. A significant carbon deposition was observed in the Ni/SDC anode in CH4, but the carbon deposition observed in Ni(BaO)/SDC was less. From the DC electrical resistance measurement of the anode films, a remarkable decrease in resistance was observed in Ni/SDC due to the carbon deposition after CH4 exposure. The resistance of Ni(BaO)/SDC was higher than that of Ni/SDC and did not change even after CH4 exposure because of the less carbon deposit. The high dispersibility of Ni particles was confirmed in both anodes and was particularly remarkable in Ni(BaO)/SDC. The highest anodic performance in Ni(BaO)/SDC was attributed to the high Ni dispersibility which might promote CH4 decomposition by producing less carbon deposit. It was speculated that the higher cell output in CH4 than that in H2 is due to the locally high concentration of H2 and/or CO gas on the anode surface by the promotion of CH4 decomposition.

A Method to Predict Fatigue Life of Additively Manufactured Metallic Parts

Additive manufacturing (AM) of metallic parts is rapidly evolving and the fatigue behavior of AM parts has become a significant concern in both industry and academia. In this paper, a method to predict the fatigue life of additively manufactured metallic parts is presented based on the electrical resistance measurement. The damage of the AM parts is characterized by the resistance change during the fatigue process. By combining the electrical resistance measurement with a continuum damage mechanics theory, a mathematical model is developed to predict the fatigue life of the AM samples. Fatigue tests were conducted under different loading conditions with AM 316L stainless steel samples. The result showed that the electrical resistance held steady at the beginning and increased gradually with the number of fatigue loading cycles. The resistance increased dramatically as the sample approached the fracture point, and this sudden increase can be used to indicate the beginning of fracture. By converting the electrical resistance to fatigue damage, experimental data was used to estimate parameters of the fatigue life model. By comparing the model prediction with experimental data, it is shown that the change of electrical resistance can be used to predict the fatigue life of additively manufactured metallic parts.

Electro-conductive carbon nanofibers containing ferrous sulfate for bone tissue engineering

The application of electroactive scaffolds can be promising for bone tissue engineering applications. In the current paper, we aimed to fabricate an electro-conductive scaffold based on carbon nanofibers (CNFs) containing ferrous sulfate. FeSO4·7H2O salt with different concentrations 5, 10, and 15 wt%, were blended with polyacrylonitrile (PAN) polymer as the precursor and converted to Fe2O3/CNFs nanocomposite by electrospinning and heat treatment. The characterization was conducted using SEM, EDX, XRD, FTIR, and Raman methods. The results showed that the incorporation of Fe salt did not induce an adverse effect on the nanofibers’ morphology. EDX analysis confirmed that the Fe are uniformly dispersed throughout the CNF mat. FTIR spectroscopy showed the interaction of Fe salt with PAN polymer. Raman spectroscopy showed that the incorporation of FeSO4·7H2O reduced the ID/IG ratio, indicating more ordered carbon in the synthesized nanocomposite. Electrical resistance measurement depicted that, although the incorporation of ferrous sulfate reduced the electrical conductivity, the conductive is suitable for electrical stimulation. The in vitro studies revealed that the prepared nanocomposites were cytocompatible and only negligible toxicity (less than 10%) induced by CNFs/Fe2O3 fabricated from PAN FeSO4·7H2O 15%. These results showed that the fabricated nanocomposites could be applied as the bone tissue engineering scaffold.

Damage assessment of CNT-doped composites through IR-thermography and electrical resistance measurement

Rooted in their heterogeneous microstructure, composite materials possess high strength-to-weight and stiffness-to-weight ratios, making them essential building blocks for a wide range of industrial applications. However, their complicated microstructure makes it difficult to predict the failure mechanism and residual life under varying external loads. The in-situ health monitoring system has received much attention in recent years as one of the promising solutions for the aforementioned limitations of composite material. In this research, we suggest a coupled health monitoring system where IR thermography and electrical resistance measurement are utilized simultaneously to diagnose the damage state of the composite materials during tensile testing. The deformation and failure timeline of GFRP under quasi-static tensile loading could be subdivided into three characteristic regions, here named as damage levels, characterized by i) elastic deformation without damage formation, ii) formation of distributed micro-damages, and iii) enlargement of concentrated damage. By employing a multiphysics simulation framework, we modeled the interplay between physical phenomena occurring in three damage stages, involving crack propagation, variation in the temperature profile and electrical resistance. The results also allowed us to have an estimation of the ‘damage stress(σD)’, a value that represents the onset of micro-damage, which has a negligible effect on the elastic properties, but might be dangerous under cyclic loading.