Direct Synthesis of Methane from Co\u3csub\u3e2\u3c/sub\u3e-H\u3csub\u3e2\u3c/sub\u3eO Co-Electrolysis in Tubular Solid Oxide Electrolysis Cells

Directly converting CO2 to hydrocarbons offers a potential route for carbon-neutral energy technologies. Here we report a novel design, integrating the high-temperature CO2–H2O co-electrolysis and low-temperature Fischer–Tropsch synthesis in a single tubular unit, for the direct synthesis of methane from CO2 with a substantial yield of 11.84%

Reduced-Temperature Solid Oxide Fuel Cells Fabricated by Screen Printing

Electrolyte films of samaria-doped ceria (SDC, Sm0.2Ce0.8O1.9) are fabricated onto porous NiO-SDC substrates by a screen printing technique. A cathode layer, consisting of Sm0.5Sr0.5CoO3 and 10 wt % SDC, is subsequently screen printed on the electrolyte to form a single cell, which is tested at temperatures from 400 to 600°C. When humidified (3% H2O) hydrogen or methane is used as fuel and stationary air as oxidant, the maximum power densities are 188 (or 78) and 397 (or 304) mW/cm2 at 500 and 600°C, respectively. Impedance analysis indicates that the performances of the solid oxide fuel cells (SOFCs) below 550°C are determined primarily by the interfacial resistance, implying that the development of catalytically active electrode materials is critical to the successful development of high-performance SOFCs to be operated at temperatures below 600°C

Fatigue life assessment of thermal cracked dies and moulds for remanufacturing

The conventional life cycle of dies and moulds is not eco-efficient, which shows great potential for the application of remanufacturing. It is of great importance to establish life evaluation technology for remanufacturers to predict the remaining service life of dies and moulds. The main contribution of this thesis is the development of key technologies for life evaluation of dies and moulds after remanufacturing through a thorough review of remanufacture related activities within the die and mould industry. It is proposed that evaluation of remaining service life of dies and moulds after remanufacturing is carried out using finite element modelling. It involves determination of residual stresses induced by repair welding, working conditions for the future operation and life model of die material. Specifically, the thesis is firstly focused on the design of representative die geometry. The geometry is optimized based on the effect of thermal loading and the effect of residual stress due to laser welding. Secondly, fatigue life model was established by conducting thermal fatigue tests and finite element modelling as well. Induction heating based test method was adopted for its capacity of achieving similar thermal shock effects. An energy based life model was derived by taking into account test period. The laser weld characteristics were studied using a sequential experimental design combining orthogonal method and uniform design. Radial Basis Function neutral networks were used to obtain regression models of weld performances for enabling process optimization. Heat source models were also calibrated by achieving sufficient agreement between numerical and experimental weld profiles. Lastly, the effect of residual stress on the fatigue life model was identified and the life model was updated. With close agreement between corresponding coefficients from two curve fittings, the corrected model is proved to be reliable for evaluating remaining useful life of remanufactured dies/moulds

Fatigue life assessment of thermal cracked dies and moulds for remanufacturing

The conventional life cycle of dies and moulds is not eco-efficient, which shows great potential for the application of remanufacturing. It is of great importance to establish life evaluation technology for remanufacturers to predict the remaining service life of dies and moulds. The main contribution of this thesis is the development of key technologies for life evaluation of dies and moulds after remanufacturing through a thorough review of remanufacture related activities within the die and mould industry. It is proposed that evaluation of remaining service life of dies and moulds after remanufacturing is carried out using finite element modelling. It involves determination of residual stresses induced by repair welding, working conditions for the future operation and life model of die material. Specifically, the thesis is firstly focused on the design of representative die geometry. The geometry is optimized based on the effect of thermal loading and the effect of residual stress due to laser welding. Secondly, fatigue life model was established by conducting thermal fatigue tests and finite element modelling as well. Induction heating based test method was adopted for its capacity of achieving similar thermal shock effects. An energy based life model was derived by taking into account test period. The laser weld characteristics were studied using a sequential experimental design combining orthogonal method and uniform design. Radial Basis Function neutral networks were used to obtain regression models of weld performances for enabling process optimization. Heat source models were also calibrated by achieving sufficient agreement between numerical and experimental weld profiles. Lastly, the effect of residual stress on the fatigue life model was identified and the life model was updated. With close agreement between corresponding coefficients from two curve fittings, the corrected model is proved to be reliable for evaluating remaining useful life of remanufactured dies/moulds

La\u3csub\u3e0.85\u3c/sub\u3eSr\u3csub\u3e0.15\u3c/sub\u3eMnO\u3csub\u3e3−\u3c/sub\u3e Infiltrated Y\u3csub\u3e0.5\u3c/sub\u3eBi\u3csub\u3e1.5\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e Cathodes for Intermediate-Temperature Solid Oxide Fuel Cells

Porous yttria-stabilized bismuth oxides (YSB) were investigated as the backbones for La0.85Sr0.15MnO3−(LSM) infiltrated cathodes in intermediate-temperature solid oxide fuel cells. The cathodes were evaluated using anode-supported single cells with scandia-stabilized zirconia as the electrolytes. With humidified H2 as the fuel, the cell showed peak power density of 0.33, 0.52, and 0.74 W cm−2 at 650, 700, and 750°C, respectively. At 650°C, the cell polarization resistance was only 1.38 Ω cm2, \u3c50% of the lowest value previously reported, indicating that YSB is a promising backbone for the LSM infiltrated cathode

Sr\u3csub\u3e2\u3c/sub\u3eFe\u3csub\u3e1.5\u3c/sub\u3eMo\u3csub\u3e0.5\u3c/sub\u3eO\u3csub\u3e6-δ\u3c/sub\u3e – Sm\u3csub\u3e0.2\u3c/sub\u3eCe\u3csub\u3e0.8\u3c/sub\u3eO\u3csub\u3e1.9\u3c/sub\u3e Composite Anodes for Intermediate-Temperature Solid Oxide Fuel Cells

Sr2Fe1.5Mo0.5O6−δ (SFM) perovskite is carefully investigated as an anode material for solid oxide fuel cells with LaGaO3-based electrolytes. Its electronic conductivity under anodic atmosphere is measured with four-probe method while its ionic conductivity is determined with oxygen permeation measurement. Samaria doped ceria (SDC) is incorporated into SFM electrode to improve the anodic performance. A strong relation is observed between SDC addition and polarization losses, suggesting that the internal SFM-SDC contacts are active for H2 oxidation. The best electrode performance is achieved for the composite with 30 wt% SDC addition, resulting in an interfacial polarization resistance of 0.258 Ω cm2 at 700◦C for La0.8Sr0.2Ga0.8Mg0.2O3−δ supported single cells. Electrochemical impedance spectroscopy analysis indicates that the high performance of SFM-SDC composite anodes is likely due to the high ionic conductivity and electro-catalytic activity of SDC by promoting the ionic exchange processes. Redox cycle treatment shows that SDC addition can even improve the redox tolerance of SFM anodes

Sr\u3csub\u3e2\u3c/sub\u3eFe\u3csub\u3e1.5\u3c/sub\u3eMo\u3csub\u3e0.5\u3c/sub\u3eO\u3csub\u3e6\u3c/sub\u3e as Cathodes for Intermediate-Temperature Solid Oxide Fuel Cells with La\u3csub\u3e0.8\u3c/sub\u3eSr\u3csub\u3e0.2\u3c/sub\u3eGa\u3csub\u3e0.87\u3c/sub\u3eMg\u3csub\u3e0.13\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e Electrolyte

The performance of Sr2Fe1.5Mo0.5O6 (SFMO) as a cathode material has been investigated in this study. The oxygen ionic conductivityof SFMO reaches 0.13 S cm-1 at 800°C in air. The chemical diffusion coefficient (Dchem) and surface exchange constant (kex) of SFMO at 750°C are 5.0 x 10-6 cm2 s-1 and 2.8 x 10-5 cm s-1, respectively, suggesting that SFMO may have good electrochemicalactivity for oxygen reduction. SFMO shows a thermal expansion coefficient (TEC) of 14.5 x 10-6 K-1 the temperature range of200–760°C in air. The polarization resistance of the SFMO cathode is 0.076 Ω cm2 at 800°C in air under open-circuit conditions measured on symmetrical cells with La0.8Sr0.2Ga0.87Mg0.13O3 (LSGM) electrolytes. Dependence of SFMO cathode polarizationresistance on the oxygen partial pressure and the cathode overpotentials at different temperatures are also studied. SFMO shows an exchange current density of 0.186 A cm-2 at 800°C in air. Single cells with the configuration of Ni-La0.4Ce0.6O2(LCO)|LCO|LSGM|SFMO show peak power densities of 349, 468, and 613 mW cm-2 at 750, 800, and 850°C, respectively using H2 as the fuel and ambient air as the oxidant. These results indicate that SFMO is a promising cathode candidate for intermediate-temperature solid oxide fuel cells with LSGM electrolyte

Design and Modeling for 2D Plate Type MR Damper

A two-dimensional magnetorheological damper is developed for the engineering two-dimensional damping need. The velocity and pressure distribution model of the two-dimensional plate-type damper, and the damping force calculation model are established based on the Navier-Stokes equation. Several structural and physical parameters, including the working gap δ, the length a, and the width a of the middle slide plate, are analyzed theoretically. The damping performance of the two-dimensional plate-type magnetorheological damper was evaluated using a two-dimensional vibration test-bed, with the effect of the excitation current analyzed. The experimental results suggest a significant influence of Coulomb damping force on the damping force of magnetorheological damper when using appropriate magnetorheological fluid. As the excitation current increases, the damping force of magnetorheological damper becomes larger while the system amplitude decreases gradually in both directions, a maximum reduction of 2.5956 times. It's confirmed that the design of the two-dimensional plate-type magnetorheological damper is reasonable

Artificial intelligence in global health equity: an evaluation and discussion on the application of ChatGPT, in the Chinese National Medical Licensing Examination

BackgroundThe demand for healthcare is increasing globally, with notable disparities in access to resources, especially in Asia, Africa, and Latin America. The rapid development of Artificial Intelligence (AI) technologies, such as OpenAI’s ChatGPT, has shown promise in revolutionizing healthcare. However, potential challenges, including the need for specialized medical training, privacy concerns, and language bias, require attention.MethodsTo assess the applicability and limitations of ChatGPT in Chinese and English settings, we designed an experiment evaluating its performance in the 2022 National Medical Licensing Examination (NMLE) in China. For a standardized evaluation, we used the comprehensive written part of the NMLE, translated into English by a bilingual expert. All questions were input into ChatGPT, which provided answers and reasons for choosing them. Responses were evaluated for “information quality” using the Likert scale.ResultsChatGPT demonstrated a correct response rate of 81.25% for Chinese and 86.25% for English questions. Logistic regression analysis showed that neither the difficulty nor the subject matter of the questions was a significant factor in AI errors. The Brier Scores, indicating predictive accuracy, were 0.19 for Chinese and 0.14 for English, indicating good predictive performance. The average quality score for English responses was excellent (4.43 point), slightly higher than for Chinese (4.34 point).ConclusionWhile AI language models like ChatGPT show promise for global healthcare, language bias is a key challenge. Ensuring that such technologies are robustly trained and sensitive to multiple languages and cultures is vital. Further research into AI’s role in healthcare, particularly in areas with limited resources, is warranted

Molecular Characterization, Tissue Distribution, Subcellular Localization and Actin-Sequestering Function of a Thymosin Protein from Silkworm

We identified a novel gene encoding a Bombyx mori thymosin (BmTHY) protein from a cDNA library of silkworm pupae, which has an open reading frame (ORF) of 399 bp encoding 132 amino acids. It was found by bioinformatics that BmTHY gene consisted of three exons and two introns and BmTHY was highly homologous to thymosin betas (Tβ). BmTHY has a conserved motif LKHTET with only one amino acid difference from LKKTET, which is involved in Tβ binding to actin. A His-tagged BmTHY fusion protein (rBmTHY) with a molecular weight of approximately 18.4 kDa was expressed and purified to homogeneity. The purified fusion protein was used to produce anti-rBmTHY polyclonal antibodies in a New Zealand rabbit. Subcellular localization revealed that BmTHY can be found in both Bm5 cell (a silkworm ovary cell line) nucleus and cytoplasm but is primarily located in the nucleus. Western blotting and real-time RT-PCR showed that during silkworm developmental stages, BmTHY expression levels are highest in moth, followed by instar larvae, and are lowest in pupa and egg. BmTHY mRNA was universally distributed in most of fifth-instar larvae tissues (except testis). However, BmTHY was expressed in the head, ovary and epidermis during the larvae stage. BmTHY formed complexes with actin monomer, inhibited actin polymerization and cross-linked to actin. All the results indicated BmTHY might be an actin-sequestering protein and participate in silkworm development