Degradation Of Components Research Articles

Analysis of Automotive Suspension System Failures and Reliability Evaluation: A Study Based on V-SIM Simulation

This article presents the factors that are conducive to the faster degradation of suspension system components with examples of typical system damage seen at diagnostic stations. Further in the article, the simulation of the deflection of the suspension system was conducted in the V-SIM 5.0 software, and the sample road consequences of damage to the system were presented. The simulation results showed that long-term use of the vehicle on uneven roads often leads to maximum deviations of the suspension system, even 150 mm. The consequence of such a condition may be its damage during driving, resulting in a road accident. The effects of damage to the suspension system were simulated while driving at a speed of 50 and 70 km/h. The article concludes with an estimation of the reliability indicators of the suspension system. Based on the results, it may be concluded that the operation of a fully loaded car in difficult conditions causes a 50% decrease in the system’s reliability as early as at a mileage of approximately 48,000 km.

Prussian Blue Analogues "Dressed" in MXene Nanosheets Tightly for High Performance Lithium-Ion Batteries.

MXenes, have been considered as a new generation anode material in lithium-ion batteries for lower lithium-ion diffusion barriers and superior conductivity. Unfortunately, their structures are prone to aggregation and stacking, hindering further shuttle of lithium ions and electrons, resulting in lower discharge capacity. Therefore, the introduction of interlayer spacers for the preparation of MXene-based hybrids has attracted much attention. Introducing Prubssian blue analogues (PBAs) as a new interlayer spacer to combine with MXene nanosheets can not only preserve the high conductivity of MXene and inhibit the volume expansion and structural degradation of the PBA component, but also inherit the characteristics of large specific surface area and high porosity of PBAs. By intelligent regulating the size of MXene sheets, Co-PBA@MXene hybrids with common sandwich-like structures and superior core-shell-like structures have been successfully obtained. Furthermore, Co@M(x:y) hybrids are prepared by intelligently adjusting the shell thickness of MXene through intelligently controlling of the mass ratio between Co-PBA and MXene. Among them, the Co@M(5:2) anode exhibits an excellent capacity (603mA h g-1 at 0.2 A g-1 after 100 cycles) and superior long-term cycling stability due to the protective and conductive properties provided by the MXene shell and multi-redox pairs and rich porosity from Co-PBA core.

Design and synthesis of JNK1-targeted PROTACs and research on the activity.

Kinase dysregulation is greatly associated with cell growth, proliferation, differentiation and apoptosis, which indicates their great potential as therapeutic targets for treatment of numerous progressive disorders, including inflammatory, metabolic and autoimmune disorders, organ fibrosis and cancer. The c‑Jun N‑Terminal Kinase (JNK), as a member of MAPK family, is proved to be a potential target for the treatment of pulmonary fibrosis, which is the most common progressive and fatal fibrotic lung disease. As a new strategy, small-molecule-mediated targeted protein degradation pathway has the advantages of catalytic properties, overcoming drug resistance and expanding target space, which can circumvent the limitations associated with kinase inhibitors. Proteolysis targeting chimeras (PROTAC) contains a linker to concatenate a ligand of E3 ubiquitin ligase and a ligand for a protein of interest (POI). We developed a total of 20 JNK1-targeted PROTACs that induce proteasomal degradation of JNK1 components. The most active PROTAC molecule PA2 was then investigated by JNK1 enzyme assay and protein degradation assay, which suggested that PA2 had an anti-JNK1 ability and provided insights for the future use of JNK1-targeted PROTAC as treatment drugs for pulmonary fibrosis.

Combination of intense pulsed light and modified atmosphere packaging delays the texture softening of apricot fruit by inhibiting the degradation of pectin components

Combination of intense pulsed light and modified atmosphere packaging delays the texture softening of apricot fruit by inhibiting the degradation of pectin components

Study on the Aging Effects of Relative Humidity on the Primary Chemical Components of Palm Leaf Manuscripts.

Palm Leaf Manuscripts represent a significant component of the world's cultural heritage. Investigating their primary chemical components and understanding the transformations these materials undergo under environmental influences are crucial for elucidating their material characteristics and aging mechanisms and developing effective strategies for preventive conservation. This study utilized infrared absorption spectroscopy and X-ray diffraction analysis to examine changes in the primary chemical components of Palm Leaf Manuscripts under varying relative humidity conditions over extended periods. The findings reveal that dry environments lead to surface cracking, while humid environments promote mold growth, both of which contribute to the degradation of the primary chemical components. These degradative processes reduce cellulose crystallinity and thermal stability. The deterioration is particularly severe under high humidity, with hemicellulose degrading faster and more extensively than cellulose under the same conditions. After 200 days of aging at 10% RH and 90% RH, cellulose degradation reached 19.82% and 54.40%, respectively, while hemicellulose degradation was 34.78% and 64.28%. Correspondingly, the relative crystallinity of cellulose decreased by 8.01% and 13.11%. In contrast, samples maintained at 50% RH exhibited minimal deterioration, with cellulose and hemicellulose degrading by only 4.08% and 13.55%, respectively, and a 6.61% reduction in cellulose crystallinity. These results suggest that a relative humidity of 50% is optimal for the preservation of Palm Leaf Manuscripts. This study offers significant insights into the ageing mechanisms and preventive conservation of Palm Leaf Manuscripts, as well as other cellulose-based organic heritage materials.

60Coγ activation of Cladophora rupestris biomass functional groups and its effect on Pb2+ adsorption.

To investigate the modification of Pb2+ adsorption of the functional groups of Cladophora rupestris (C. rupestris) biomass by gamma radiation (60Coγ-ray), the interface structure, chemical properties, adsorption behaviors, and Pb2+ adsorption mechanisms of C. rupestris biomass were investigated after irradiation with varying doses of 60Coγ-ray. The results indicate that 60Coγ-ray significantly changed the surface characteristics and interfacial chemistry of the C. rupestris biomass.This led to fracturing and fragmentation that produced a larger specific surface area and more abundant pore structure, increasing the electronegativity in the C. rupestris biomass. The theoretical Pb2+ adsorption capacity increased significantly (2.6-2.9 times) after 60Coγ-ray irradiation. 60Coγ-ray caused preferential degradation of protein components in the dissolved organic matter of the C. rupestris biomass, and protein deamination increased the absorption sites of cations. In the C. rupestris biomass, 60Coγ-ray altered the elemental composition and functional groups, particularly the carbon- and oxygen-containing functional groups, to improve Pb2+ adsorption. In conclusion, 60Coγ-ray can activate the functional groups of C. rupestris biomass and improve their Pb2+ adsorption sites. This study provides new insight into modification of biomass materials for enhanced removal of heavy metals from waterbodies.

Autophagy and Protein Quality Control in Parkinson's Disease.

Autophagy is a vital cellular process responsible for the degradation of proteins, organelles, and other cellular components within lysosomes. In neurons, basal autophagy is indispensable for maintaining cellular homeostasis and protein quality control. Accordingly, lysosomal dysfunction has been proposed to be associated with neurodegeneration, and with Parkinson's disease (PD) in particular. Aging, dopamine metabolism, and PD-linked genetic mutations are thought to impair the autophagic-lysosomal pathway, disrupt cellular proteostasis, and contribute to PD pathogenesis. These alterations represent an opportunity to identify potential new therapeutic targets and disease biomarkers, thus laying the groundwork for the development of novel disease-modifying strategies for PD that are aimed at restoring cellular proteostasis and quality control systems.

The Novel Coupling of Operando Methods: Electrochemical Dilatometry with Mass Spectrometry Using the Example of a Li|Graphite Half Cell

The aging of lithium-ion cells critically affects their lifetime, safety, and performance, particularly due to electrode and electrolyte degradation. This study introduced a novel combined-measurement cell-integrating operando dilatometry and operando mass spectrometry to observe real-time physical and chemical changes during electrochemical cycling. Operando dilatometry measures thickness changes in the working electrode, while operando mass spectrometry analyzes gas emissions to provide insights into the underlying degradation processes. The results indicated significant correlations between electrochemical behavior, thickness changes, and gas evolution, revealing both the reversible and irreversible growth of constituents on particles and the electrode surface. The formation of the solid electrolyte interphase due to the degradation of electrolyte components, such as solvents or conductive salts, is identified as a key factor contributing to irreversible changes. The operando gas analysis highlighted the presence of decomposition intermediates and products, which are all linked to electrolyte degradation. Additionally, post-mortem gas chromatography coupled with mass spectrometry identified several compounds, confirming the presence of different decomposition pathways. This integrated and holistic approach deepened the understanding of the aging mechanisms at the electrode level.

Comparative genomics of carbohydrates utilization in bacteria of the family <i>Sphaerochaetaceae</i>: evolutionary origin of the genes encoding galacturonidase and unsaturated rhamnogalacturonyl hydrolase

A comparative analysis of carbohydrate degradation proteins encoded in currently available genomic sequences of bacteria of the family Sphaerochaetaceae, namely Sphaerochaeta associata GLS2T, S. globosa BuddyT, S. pleomorpha GrapesT, S. halotolerans 4-11T, S. halotolerans 585, Sphaerochaeta sp. S2, Sphaerochaeta sp. PS and Parasphaerochaeta coccoides SPN1T was carried out. The genomes of Sphaerochaeta spp. encode a medium-sized and diverse set of proteins potentially involved in the degradation of different classes of carbohydrates, mainly oligosaccharides. All studied genomes encode glycoside hydrolases of the GH1, GH2, GH3, GH4, GH13, GH20, GH28, GH36, GH43, GH57, GH63, GH77 and GH105 families, as well as carbohydrate esterases of the CE8 and CE9 families. All studied bacteria, with the exception of P. coccoides SPN1T, have many proteins of the GH31 family encoded in their genomes. The studied representatives of Sphaerochaetaceae do not have genes coding for endo-β-acetylmuramidase (lysozyme) of the GH23 family involved in the process of peptidoglycan turnover. However, the genomes of S. associata, S. globosa, Sphaerochaeta sp. PS and S. pleomorpha contain the exo-β-acetylmuramidase gene (GH171 family). A significant part of the genes encoding carbohydrate degradation enzymes have the closest homologues among representatives of the phyla Bacillota, Bacteroidota, and Pseudomonadota. The genomes of the studied bacteria encode proteins that could potentially be involved in the degradation of pectin. The ability of representatives of Sphaerochaetaceae to use pectin for growth, as well as the evolutionary origin of genes encoding potential α-galacturonidase (GH4 family) and unsaturated glucuronyl/rhamnogalacturonyl hydrolase (GH105 family), involved in the degradation of pectin components, were studied.

High tribo-corrosion resistance of Ni-Cr-5Al2O3 thermal spray coating: a comparison of post processing techniques

Abstract Engineering materials are known to show degradation in terms of tribo-corrosion characteristics in marine environment. The concurrent increase in erosion and corrosion resistance can make them more appealing for structural applications. The thermal spray coatings are typically used to mitigate the degradation of structural components. Although, the microstructure of as-sprayed coating indicates inconsistency in the form of distinct splats and elemental segregation. Furnace annealing, microwave processing and stationary friction processing (SFP) are performed to improve the non-homogeneous microstructure of the thermal spray coating. SFP has several attractive properties to refine the grain structure and reducing the defects density on the surface. Therefore, SFP has been explored as a surface modification technique for thermal spray coating with an aim to enhance the performance of the processed coating. Slurry erosion and erosion corrosion tests are conducted on as-sprayed and processed coatings at normal and oblique impingement angle. Erosion rate of SFPed specimen is comparatively lower than that of the as-sprayed, furnace annealed and microwave processed specimens in both slurry erosion and erosion corrosion. Furthermore, the SFPed coating indicated least corrosion rate as compare to furnace annealed, microwave coating and as-sprayed coating.

Operation Optimization Framework for Advanced Reactors Using a Data-Driven Digital Twin

Abstract To meet future energy demand, while producing safe, reliable, and carbon-free energy, nuclear reactors will be needed. To make next-generation reactors more economically competitive, the Artificial Intelligence and Machine Learning-based operation optimization module of the dynamic operation and maintenance optimization (DyOMO) framework is proposed. The operation optimization module of DyOMO consists of a data-driven digital twin coupled to a genetic algorithm (GA) optimizer to quickly and efficiently search the solution space for optimal control schemes. The digital twin consists of a Bayesian Network (BN) known as MVCBayes to incorporate uncertainty in the optimization and feedforward neural networks (FFNN) as MVCNet with GA to conduct the optimization. Over time as reactor systems are operating, component degradation will cause the system's electrical output to decrease or be shutdown entirely to perform maintenance. To prevent this, the DyOMO operation optimization module aims to prolong system operation until the next scheduled maintenance period using multiple variable control (MVC) that simultaneously perturbs all actuators to better control the reactor. Comparing this approach with traditional single variable control (SVC), MVC can extend reactor operation past 5% degradation while SVC begins to struggle once the pump and turbine degradation surpasses 0.85% for load-following (LF) operation. Given this extra operation time, the system can continue to run while maximizing its safety margin until the next scheduled shutdown and potentially decrease the total number of maintenance actions throughout the license period to decrease operational and maintenance (O&M) costs.

Analysis of the Thermomechanical Behavior of SiC/Si/TiSi<sub>2</sub> Cermets Manufactured with Waste Wood from Capirona and Capinuri Peruvian Species

This study analyzes the thermomechanical behavior of SiC/Si/TiSi2 cermets manufactured from Peruvian wood waste of the Capirona and Capinuri species. A sustainable manufacturing process was used that uses sawdust as a precursor. The mechanical properties under compression and the elastic modulus of the cermets were characterized from room temperature to 1400°C. At room temperature, the values achieved exceed 500 MPa in both cermets, with the Capinuri precursor being slightly higher in maximum compressive strength with 691 MPa, but in elastic modulus, the Capirona cermet has a rigidity of 159 GPa. At 500°C, the cermets showed a small reduction in their mechanical performance. At 1100°C, a decrease in strength was observed to 248 MPa for Capinuri and 292 MPa for Capirona and in Young's modulus to 85.18 GPa and 91.92 GPa respectively. At 1400°C, both cermets suffered a significant deterioration of their mechanical properties due to a presumed chemical degradation of the individual components. The results demonstrate the feasibility of using wood waste as precursors for the sustainable manufacturing of advanced composite materials, however, optimization of manufacturing parameters and processes should be considered to improve the performance and stability of this material.

Intraoperative Use of Sodium Bicarbonate Ringer's Solution Instead of Sodium Lactate Ringer's Solution to Reduce Endothelial Glycocalyx Degradation and Improve Postoperative Recovery During Cardiopulmonary Bypass Cardiac Surgery: A Single-Center Prospective Cohort Study.

To investigate the effect of sodium bicarbonate Ringer's solution (BRS) on the degradation of endothelial glycocalyx components in patients undergoing cardiopulmonary bypass (CPB) during cardiac surgery, and to evaluate its impact on endothelial glycocalyx preservation and postoperative recovery. A total of eight patients scheduled for elective CPB heart surgery were included and randomly divided into two groups: the sodium lactate Ringer's solution (LRS) group and the BRS group. ELISA was used to measure plasma concentrations of syndecan-1, matrix metalloproteinase-9 (MMP-9), matrix metalloproteinase-3 (MMP-3), IL-6, IL-8, TNF-α, and TGF-β at predefined time points: T0 (before induction of anesthesia), T3 (immediately after weaning from CPB), T5 and T6 (24 and 72hours postoperatively). Serum creatinine concentrations were measured within 48hours postoperatively. The incidence of postoperative delirium (POD) was assessed three days after surgery. Postoperative mechanical ventilation time, duration of stay in the intensive care unit and hospital stay were also documented. The BRS group had significantly lower plasma concentrations of syndecan-1 at T3 (7.98 [7.43, 8.92] ng/mL vs 9.54 [8.4, 10.73] ng/mL, P < 0.001) and T5 (4.20 [3.31, 4.96] ng/mL vs 5.40 [3.95, 6.55] ng/mL, P = 0.001) in comparison with the LRS group (P<0.01). Syndecan-1 levels in both groups were similar at T6 (3.18 [2.88, 3.5]ng/mL vs 3.12 [2.77, 3.45] ng/mL, P > 0.05). Additionally, MMP-9, MMP-3, IL-6 and IL-8 were significantly lower at T3 and T5 in the BRS group (P<0.05 and P<0.01, respectively). However, no significant differences were observed between the two groups in the incidence of acute kidney injury (AKI) or POD (P > 0.05). BRS has the potential to reduce glycocalyx degradation in patients undergoing heart valve surgery with CPB. However, both groups demonstrated similar post-postoperative clinical outcomes, including the rates of AKI and POD.

Unveiling the role of sintering temperatures in the physical properties of Cu-Mg ferrite nanoparticles for photocatalytic application

This research presents an explicit analysis of the effects of sintering temperature (Ts) on the structural, morphological, magnetic, and optical properties of Cu0.5Mg0.5Fe2O4 nanoferrites synthesized via the sol-gel method. To accomplish it, Cu-Mg ferrite NPs were sintered at temperatures ranging from 300 to 800 °C in increments of 100 with a constant holding duration of 5 h. Thermogravimetric analysis was used to observe the degradation of organic components and the thermally stable zone of the material. XRD analysis and SAED patterns revealed the formation of a single face-centred cubic (fcc) spinel structure with an Fd–3m space group. The particle's crystallite sizes have grown from 4.54 to 102.54 nm as Ts have increased, consistent with TEM results. Further evidence for the creation of spinel structure was provided by two prominent absorption bands in FTIR spectroscopy below 1000 cm−1. The particles were found to have a densely packed, nearly spherical morphology, as confirmed by TEM images. The EDS was utilized to identify the chemical species that were present in the sample. A significant correlation was observed between particle size and magnetic properties. The field-dependent magnetization investigations revealed that particles with crystallite sizes of 4.54 and 5.10 nm were superparamagnetic, while those measuring 11.68, 23.81, 42.95, and 102.54 nm exhibited ferrimagnetic characteristics. Furthermore, it was revealed that an increase in sintering temperature results in a concurrent amplification of crystallites, which subsequently heightens the saturation magnetization of the prepared NPs from 9.49 to 33.04 emu/g. The coercivity value clarifies the sintering effect of transforming the particle from a single-domain to a multi-domain magnetic state. The finite-size scaling formula precisely characterizes the changes in Curie temperature. In addition, the semiconducting characteristics of Cu-Mg ferrite NPs were confirmed through DRS, which unfolded an optical band gap within the range of 1.84–2.26 eV. The Mulliken electronegativity approach unveiled the prospective efficacy of these NPs in photocatalytically generating O2 from water. Cu-Mg nanoferrites exhibit a favourable bandgap and potential as a photocatalyst, rendering them a potentially fruitful addition to the family of ferrite materials utilized in photocatalytic and associated solar energy applications.

Redundancy Allocation Problem for a Continuous‐State Series‐Parallel System With Degrading Components: Electric Vehicle Application

ABSTRACTSystem reliability is a critical factor in designing complex engineering systems. Redundancy allocation problem (RAP) has attracted more interest owing to its wide scope of industrial applications for system reliability optimization. RAPs for binary‐state and multistate systems have been extensively studied. However, the redundancy allocation for continuous‐state systems composed of degrading components has not yet been fully explored. This study attempts to build the RAP for the continuous‐state parallel‐series system consisting of identical, independent, and nonrepairable components under active and cold‐standby redundancy strategies. The degradation of individual components in a system is continuous and modeled by the gamma process. The degradation at the system level is derived according to a deterministic structure function that relates the system degradation to the degradation of its components. Genetic algorithm and exhaustive search method are used to find the cost‐optimal redundancy design while satisfying a system reliability requirement. Series‐parallel lithium‐ion battery pack systems for electric vehicles (EVs) are used as an illustrative example to validate the proposed RAP and optimization model.

A novel model-based diagnostics for identifying component degradations in gas turbines for power generation

Improving the accuracy of gas turbine performance diagnosis is important for reducing maintenance costs. Conventional model-based diagnostics use either compressor map adaptation based on correction curves or compressor map scaling based on an assumed ratio of fouling factors. However, they usually do not reflect the characteristics of the actual gas turbine. In this study, adaptation of both the compressor and turbine maps was carried out. The ratio of fouling factors was determined by quantifying the actual fouling factors so that the novel diagnostics could be applied to any gas turbine. The novelty of the proposed diagnostics is that it identifies component degradations individually, particularly distinguishing between compressor and turbine degradations using only measurement data. To demonstrate the capabilities of the proposed diagnostics, the method was applied to a 180-MW-class gas turbine operated over a long period with off-line washing. According to the results, the compressor air flow rate before off-line washing was reduced by 3.1 kg/s. Consequently, the power and efficiency of the gas turbine decreased by 3.5 MW and 0.43%p, respectively. The diagnosis results after off-line washing showed that the air flow rate and efficiency of the compressor were fully recovered, but the turbine efficiency was still degraded by 0.49%p. As a result, it was found that the gas turbine power and efficiency were not recovered by 1.2 MW and 0.33%p. The results showed that the component degradations could be identified individually. The novel diagnostics is expected to be used in a variety of strategies to reduce maintenance costs.

Accelerated Stress Tests Protocol Development for Industrial PEM Electrolyzer Stacks

The deployment of NEL’s next-gen PEM water electrolyzer stacks and systems is very much dependent on our ability to evaluate the degradation of individual components and thereby predict 50000 hr. operability of the stack. In addition, Nel Hydrogen is constantly working to unveil degradation mechanisms from our long run (< 100.000 hours) fielded stacks, so that we can make the developing of accelerated stress tests (ASTs) less challenging. Typically, performance losses in PEM electrolyzer stacks are the result of electrode, membrane, and/or PTL degradation during different operation strategies. Here we accelerated the performance losses of electrodes used in PEM water electrolyzer stacks using an in-house developed voltage cycling protocol. Membrane degradation was also accelerated through cation-doped catalyst coated membranes and is assessed through ex-situ monitoring of fluoride emission rates during the stack operation. We also leveraged a fielded Nel Hydrogen legacy PEM stack that ran for over 50000 hr. and other R&D stacks that ran for intermediate life span of 5000 hr. at steady state. A correlation of the degradation mechanism to different cell components observed from that of the AST protocols is then here reported.

Investigating Reverse Current Phenomena Induced by Start/Stop Cycling in Lab-Scale Single-Cell Liquid Alkaline Water Electrolyzers

Liquid alkaline water electrolyzers (LAWEs) represent one of the most mature hydrogen production technologies. Large-scale alkaline electrolysis plants have already been deployed at the 100MW scale. Developments advancing LAWEs are crucial in meeting the soaring demand for hydrogen, driven by efforts to combat carbon emissions and transition to cleaner energy sources. Integrating LAWEs with renewable energy sources like wind and solar holds the potential to facilitate the production of green hydrogen at a low cost. However, a significant challenge arises when coupling LAWE with inherently intermittent renewable energy sources. This challenge comes from the reverse current phenomenon following shutdown, which accelerates the degradation of electrolyzer components, including bipolar plates and electrodes. Typically, when an electrolyzer is shutdown, the anode and cathode on the bipolar plate of neighboring cells discharge rapidly. This causes current to flow through the bipolar plates in the opposite direction to normal electrolysis operation. This results in the oxidation of the cathode and the reduction of the anode. While this phenomenon is observed in industrial-scale electrolyzers and multi-cell stacks, it is relatively difficult to replicate in lab-scale single-cell LAWE setups, where bipolar plates are not typically utilized.Many researchers have proposed various start/stop cycling protocols aimed at mimicking the reverse current phenomenon to study the degradation of electrocatalysts or electrodes in lab-scale LAWE setups. These protocols often involve voltage or current cycling. However, despite these efforts, the reverse current phenomenon and start/stop cycling protocols are not yet fully understood. Additionally, there remains uncertainty on how these findings can be confidently extrapolated to industry-scale LAWE components. In this study, we have systematically examined several start/stop strategies and their impacts on LAWE performance and component durability. Furthermore, we have applied these start/stop cycling protocols to various anode and cathode catalysts to determine whether these protocols are exclusively applicable to conventional nickel electrodes or universal in nature. The authors would like to acknowledge the support of the U.S. Department of Energy, and the Hydrogen from Next-Generation Electrolysis of Water (H2NEW) Consortium for their support.

Advanced Bipolar Plates for the Next Generation PEM Water Electrolyzers: Flow-Field Design, Fabrication, and Optimization

Flow-fields, responsible for distributing reactants, like water for electrolysis, evenly across the active area of the cell as well as removing by-products, are key to achieving high efficiency and longevity in proton exchange membrane water electrolyzers (PEMWEs). Current problems include the complex interplay between fluid dynamics and electrochemical reactions leading to uneven distribution of reactants, which can cause hot spots and accelerated degradation of the cell components. Furthermore, the geometry of flow channels can result in increased pressure drop and higher energy consumption for the pumping of reactant fluids, directly impacting the overall efficiency and scalability of the technology.For PEMWEs, hydration of reaction sites in the membrane is a crucial factor that significantly influences their efficiency and performance. This study explores the rapid production and testing of multiple novel flow field geometries, each designed to increase cell performance due to multiple different factors. Each flow-field is designed, fabricated, and tested with a state-of-the- art MEA at operating conditions typical for an industrial electrolyzer. The performance of each flow-field design is compared against all other designs explored. Critical information about the impact of the pressure drop and the flow-field contact area upon the electrode is collected. Using this data, the performance of various flow-field designs is derived and discussed in this work.

Degradation Prediction of Solid Oxide Cell Considering Ni Coarsening Model Based on Electrode Microstructure Measurement

Introduction To further accelerate the development of solid oxide cells (SOCs), a computer-aided design and simulation method is important to visualize the characteristics of SOCs. There is an essential issue with clarifying various internal degradation phenomena for durability which is important for visualizing the characteristics. Various mechanisms have been reported for the degradation of electrodes, electrolytes, and other components [1]. The coarsening of Ni is attracting attention as a major cause of fuel electrode degradation. A theoretical time-dependent model of Ni grain size and TPB density change through microstructural observation has been suggested to simulate the degradation of fuel electrodes in solid oxide fuel cells [2].Since the electrode degradation is generally affected by loading current, overvoltage, and distributions of gas species and temperature [3], it is important to understand the spatial distribution of these factors when developing a SOC system. Therefore, a precise analysis of degradation factors, such as the causal relationship with operating conditions, is necessary to quantitatively clarify the degradation mechanism. Therefore, if multi-physics simulation technology can be utilized to predict degradation, the development of more durable SOCs can be accelerated.Our research group has converted the microscopic electrochemical reaction phenomena into a mathematical equation that captures it as macroscopic phenomena by considering the apparent exchange current density, and has reflected it in the simulations [4-6]. Simulation results are consistent with experimental I-V characteristics and temperature distributions, suggesting that various spatial distributions can be predicted for the performance of the initial, non-degraded cells [6].Therefore, this study aims to establish a method to predict the amount of change in cell performance due to time-dependent degradation of Ni cermet by quantifying Ni coarsening through microstructural observation and reflecting the time-dependent model in the apparent exchange current density equation. The establishment of the suggested method will make it possible to predict SOC degradation when designing the SOC, and is expected to contribute to improving durability in actual SOC system development. Experimental To develop the time-dependent Ni coarsening model, we conducted cell durability tests and observed the electrode microstructure after the tests. An electrolyte-supported cell with scandia-stabilized zirconia (ScSZ, 200 µm thick) as electrolyte, Ni-ScSZ cermet as fuel electrode, and gadolinia doped ceria (GDC) buffer layer and lanthanum strontium cobalt ferrite (LSCF) as air electrode was used in this study. Humidified hydrogen was supplied to the fuel electrode at 100 ml min-1 and air was supplied to the air electrode at 150 ml min-1. The electrode microstructure was observed before and after the tests. The fuel electrode microstructure image before the test is shown in Fig. 1.A three-dimensional model simulating the cell geometry and operating conditions such as temperature and flow rate used in actual experiments was used in the simulation. In this study, calculated I-V characteristics and temperature distributions were obtained in a relatively low current density range consistent with experimental conditions to evaluate the relationship between cell performance and degradation due to Ni coarsening.In this presentation, we will report the discussion of the calculated results incorporating the Ni time-dependent model compared with experimental results. References Z. Golkhatmi, M. I. Asghar, and P. D. Lund, Renew. Sustain. Energy Rev., 161, 112339 (2022).Hubert, J. Laurencin, P. Cloetens, B. Morel, D. Montinaro, and F. Lefebvre-Joud, J. Power Sources, 397, 240 (2018).Hagen, R. Barfod, P. V. Hendriksen, Y. L. Liu, and S. Ramousse, J. Electrochem. Soc., 153, A1165 (2006).Fukumoto, N. Endo, K. Natsukoshi, Y. Tachikawa, G. F. Harrington, S. M. Lyth, J. Matsuda, and K. Sasaki, Int. J. Hydrogen Energy, 47, 16626 (2022).Fukumoto, N. Endo, K. Natsukoshi, Y. Tachikawa, G. F. Harrington, S. M. Lyth, J. Matsuda, and K. Sasaki, ECS Trans., 109, 15 (2022).Yoshiga, T. Okamoto, Y. Tachikawa, and K. Sasaki, ECS Trans., 112, 129 (2023). Figure 1