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Blending hydrogen into natural gas grid can effectively reduce carbon emissions and promote the development of the hydrogen economy. Utilizing hydrogen-natural gas mixtures through internal reforming solid oxide fuel cells (SOFCs) can convert the chemical energy of the fuels direct into electricity, which is a promising technology for combined heat and power systems. In this study, a three-dimensional model for an internal reforming solid oxide fuel cell unit is developed coupling chemical and electrochemical reactions, mass, momentum, and heat transfer processes. The influences of the hydrogen addition on the distributions of temperature, gas compositions, and current density are studied by changing the hydrogen blending ratios in inlet gas mixtures. The simulation results show that the addition of hydrogen affects the coupling of the endothermic reforming reactions and exothermic electrochemical reactions, which leads to improved temperature uniformity and higher current density of the SOFC unit compared with pure methane feeding.

In this study, a novel current collecting method was designed and demonstrated by inserting a metal wire brush into the anode supported micro-tubular SOFC. The new design enables a tight and stable contact between the wire and the inner wall of the anode which leads to a fine performance of the SOFC. Different kinds of metal wires were applied, where the copper wire brush (CZWB) shows a better performance than the stainless steel wire brush (SSWB). At a temperature of 700? and a fuel feed of hydrogen, the SOFC using CZWB can achieve a maximum power density of 290 mW/cm2 and an ohmic resistance of 0.66 ??cm2. And the brush size has been approved to have little effect on the ohmic resistance. A 108 h long-time discharge test was carried on, resulting with a degradation rate of 1.728?/h and indicating a relative stability.

Identifying the degradation mechanisms at the early stage of operation is important for the long-term operation of solid oxide fuel cells (SOFCs). Compared to conventional methods, total harmonic distortion analysis (THDA) can significantly reduce the test time for identifying performance degradation during SOFC operation. In this study, a one-dimensional transient elementary reaction kinetic model of an SOFC fueled with syngas is developed. The model incorporates the coupling effect of elementary chemical and electrochemical reactions, the electrode microstructure, the charge and mass transport processes, and the detailed evolution reaction of surface adsorbed carbon. A THDA simulation calculation method was developed and applied to determine the failure mode of anode carbon deposition. The amplitude, duration, and harmonic number of the perturbation signal are determined to improve fault detection for THDs. The results show that the use of THD can not only detect carbon accumulation behavior at the early stage of SOFC operation but also distinguish the specific degradation mechanism caused by carbon deposition: the hindered SOFC charge transfer reaction can be detected in the frequency range of 100–4000 Hz, and the hindered gas diffusion process inside the anode can be detected in the frequency range of 0.01–10 Hz.

ABSTRACTThe gut microbiota and bile acid metabolism are key determinants of the response of inflammatory bowel disease to biologic therapy. However, the molecular mechanisms underlying the interactions between the response to anti-α4β7-integrin therapy and the gut microbiota and bile acid metabolism remain unknown. In this research, we investigated the role of gut microbiota-related bile acid metabolism on the response to anti-α4β7-integrin therapy in a humanized immune system mouse model with colitis induced by 2,4,6-trinitrobenzene sulfonic acid. We found that anti-α4β7-integrin significantly mitigated intestinal inflammation, pathological symptoms, and gut barrier disruption in remission-achieving colitis mice. Whole-genome shotgun metagenomic sequencing demonstrated that employing baseline microbiome profiles to predict remission and the treatment response was a promising strategy. Antibiotic-mediated gut microbiota depletion and fecal microbiome transplantation revealed that the baseline gut microbiota contained common microbes with anti-inflammatory effects and reduced mucosal barrier damage, improving the treatment response. Targeted metabolomics analysis illustrated that bile acids associated with microbial diversity were involved in colitis remission. Furthermore, the activation effects of the microbiome and bile acids on FXR and TGR5 were evaluated in colitis mice and Caco-2 cells. The findings revealed that the production of gastrointestinal bile acids, particularly CDCA and LCA, further directly promoted the stimulation of FXR and TGR5, significantly improving gut barrier function and suppressing the inflammatory process. Taken together, gut microbiota-related bile acid metabolism-FXR/TGR5 axis may be a potential mechanism for impacting the response to anti-α4β7-integrin in experimental colitis. Thus, our research provides novel insights into the treatment response in inflammatory bowel disease.

Microtubular solid oxide fuel cell (mTSOFC) is a clean and low carbon emission power generation technology that has great prospects in the field of portable power generation. Improving the efficiency and broadening the variety of available fuels can significantly improve the performance of portable power generation devices based on mTSOFC. In this study, mTSOFC stack assembled by mounting modular sub-stacks in an array on a designed fuel/air distribution base were tested. By changing the connection of the current collection nodes, the influence of circuit connection modes on the overall output performance of the stack was studied. At a temperature of 700℃ and a fuel feed of hydrogen, the mTSOFC stack composed of 6 sub-stacks can achieve a maximum power of 353W. Fuel cascade utilization was realized by transferring the spent fuel gas from the upstream sub-stacks to the downstream sub-stacks. A maximum power generation efficiency of 45.67% was achieved in the two-cascade stack. The feasibility of using hydrogen, ammonia, propane and diesel as fuel for the mTSOFC stack has also been experimentally verified. A total continuous discharge time of 21h was achieved at an average power ≥ 190W under ammonia feeding conditions.