Long-term Operation Research Articles

Stochastic optimization to maximize water supply index in conjunctive use of surface and groundwater

Systematic operation of water resources systems requires rules that consider the uncertainties affecting system performance. Here, stochastic dynamic programming (SDP) is used to structure and solve a full-scale surface and groundwater conjunctive use model to derive a multiparameter operational policy (rule) that maximizes the water supply index (WSI). The model uses a Markovian representation of inflows to account for hydrologic uncertainties. Both the reliability of allocated water and its vulnerability are employed to define the WSI. To overcome the computational burden inherent with SDP, infeasible solutions are identified and removed from the model solution process. Optimal expected values of WSI and surface and groundwater uses are assessed. The system simulation model with embedded rules is executed to assess the performance of the derived rules. The derived rules employ water rationing and account for long-term benefits during periods when the available surface and groundwater resources may suffice to meet demand. The simulation results demonstrate that the derived operational rules produce high WSI values for the long-term operation of the system and ensure sustainable groundwater use.

Precursor-chemistry engineering toward ultrapermeable carbon molecular sieve membrane for CO2 capture

Carbon capture is an important strategy and is implemented to achieve the goals of CO2 reduction and carbon neutrality. As a high energy-efficient technology, membrane-based separation plays a crucial role in CO2 capture. It is urgently needed for membrane-based CO2 capture to develop the high-performance membrane materials with high permeability, selectivity, and stability. Herein, ultrapermeable carbon molecular sieve (CMS) membranes are fabricated by pyrolyzing a finely-engineered benzoxazole-containing copolyimide precursor for efficient CO2 capture. The microstructure of CMS membrane has been optimized by initially engineering the precursor-chemistry and subsequently tuning the pyrolysis process. Deep insights into the structure-property relationship of CMSs are provided in detail by a combination of experimental characterization and molecular simulations. We demonstrate that the intrinsically high free volume environment of the precursor, coupled with the steric hindrance of thermostable contorted fragments, promotes the formation of loosely packed and ultramicroporous carbon structures within the resultant CMS membrane, thereby enabling efficient CO2 discrimination via size sieving and affinity. The membrane achieves an ultrahigh CO2 permeability, good selectivity, and excellent stability. After one month of long-term operation, the CO2 permeability in the mixed gas is maintained at 11,800 Barrer, with a CO2/N2 selectivity exceeding 60. This study provides insights into the relationship between precursor-chemistry and CMS performance, and our ultrapermeable CMS membrane, which is scalable using thin film manufacturing, holds great potential for industrial CO2 capture.

Carbon Nanocage Supported Asymmetrically Coordinated Nickle Single-Atom for Enhanced CO2 Electroreduction in Membrane Electrode Assembly.

Designing efficient catalysts for operating CO2 electroreduction in membrane electrode assembly (MEA) faces significant obstacles. Herein, we propose an asymmetrically coordinated Ni single-atom catalyst featuring axial Br coordination at NiN4Br sites anchoring onto hollow Br/N co-doped carbon nanocages, achieved through a NaBr-assisted confined-pyrolysis strategy. The Ni-NBr-C catalyst exhibits a high CO Faradaic efficiency (FECO>97 %) over the current density range of 50 to 350 mA cm-2 in the MEA device. Furthermore, Ni-NBr-C shows a stable cell voltage of 2.66±0.2 V while delivering a large current density of 350 mA cm-2 over an 85-hour long-term operation, demonstrating its potential for industrial-scale applications. Advanced characterization techniques and theoretical calculations reveal that the coordination and doping of Br not only enhance the intrinsic activity but also highlight that the unique pore structure improves mass transfer efficiency.

Replacement depth and lifespan prediction of enhanced bioretention media under TSS impact conditions

ABSTRACT The enhanced bioretention system provides a new way to solve the problems of stormwater management brought by urbanization. The knowledge on effects of media modification and long-term operation is scattered, so clogging interaction function, clogging time and depth are analysed to uncover the underneath. River sand, loess, and compost were used as basic fillers, and air-dried water treatment residual (WTR) and recycled aggregate from construction waste (RACW) were used as modifiers to formulate mixed fillers, and synchronized observation of the change rule of hydraulic conductivity and porosity of vertical layering. The study found that the infiltration coefficient of each system tended to decay gradually from top to bottom as the influent TSS accumulated. A set of improved media clogging process prediction framework has been proposed, using rainfall conditions in Northwest China as input conditions, the system clogging time is about 5.5∼7.1 years and the depth of replacement is about 35 cm based on the principles of cake filtration and deep filtration. The results can further understand the function variation of bioretention system under TSS impact conditions, which is helpful to the prediction of the operating life of the system and the evaluation of media replacement depth.

Inversion method for working behavior of prestressed anchor cables in dam foundation driven by structural health monitoring data

Accurate knowledge of the working behavior of prestressed anchor cables is essential to ensure the long-term safe operation of dams. However, due to the lack of effective monitoring means, it is hard to analyze the working performance of anchor cables, and there is still a lack of methods to accurately quantify the anchorage effectiveness of prestressed anchor cables in actual hydraulic engineering projects. To solve this problem, this paper presents an inversion method to accurately quantify the behavior of prestressed anchor cables in dam foundations using structural health monitoring data. Firstly, Ensemble Empirical Mode Decomposition (EEMD) and Singular Spectrum Analysis (SSA) are used to denoise monitoring sequences. Secondly, the hydraulic pressure deformation component is separated by constructing a statistical model reflecting the relationship between dam deformation and environmental factors. Meanwhile, a three-dimensional finite element model (FEM) of the dam and its foundation is established in which the water load and anchoring force are applied step by step to simulate the deformation values of the dam under different combinations of working conditions. And a BP neural network is used to fit the finite element forward process. Finally, the inferred values of the anchorage force are derived by comparing the deformation separated by the statistical model with the deformation calculated by the FEM. In order to minimize the fitting difference of the two series of deformations, an improved grey wolf optimization algorithm (IGWO) is introduced to optimize the inverse calculation. The method is applied to a multiple arch dam foundation anchorage project, and its feasibility and effectiveness are verified. The proposed method is capable of providing effective support for ensuring the safe service of prestressed anchor cables of dams.

Annealing, design and long-term operation of graphite crucibles for the growth of epitaxial graphene on SiC

We describe the annealing, geometry, storage, and lifespan of graphite crucibles for the growth of epitaxial graphene on SiC. We monitor residual gas content during the annealing of the as-manufactured graphite crucible before the growth of the first graphene samples. The high-temperature evolution of carbon monoxide points towards the reaction of solid carbon and residual water. Therefore, we propose a procedure consisting of four annealing cycles to eliminate this reaction. The residual gas evolution after long-term storage of well-baked crucibles in the air shows a similar increase in water and carbon monoxide as that in unbaked crucibles. Hence, we propose the crucible storage in argon ambient. Further, we discuss the role of the crucible shape on graphene quality. Namely, we compare the cylindrical semi-closed crucible to the flat opened crucibles. The flow-aided gas exchange in the opened crucible is more beneficial for graphene growth than the diffusion-driven gas exchange in the semi-closed cylindrical crucibles. The flow-aided gas exchange leads to more efficient removal of outgassed residual contaminants, thus outperforming the advantage of increased silicon vapor pressure in the semi-closed cylindrical crucible. We also study the graphite crucible lifespan, showing that the aged crucible leads to the enhanced inhomogeneous strain in graphene.

Dissecting spacer induced membrane deformation and fluid hydraulic behavior in reverse osmosis

Feed spacer is a key component of the spiral wound membrane module. However, the membrane deformation induced by the feed spacer under high pressure presents a significant challenge to long-term operation of reverse osmosis (RO) membrane. This deformation alters the fluid hydraulic behavior within the feed channel and its underlying mechanism remains elusive. In this study, the computational fluid dynamics (CFD) simulation was conducted to illustrate the impact of the feed spacer geometry on membrane deformation under high pressure and the resultant changes in hydraulic performances. The simulated results revealed that an increase in the mesh angle and a reduction in the filament diameter and length, led to a higher degree of membrane deformation. In addition, larger mesh angles and filament diameters, and shorter the filament lengths could significantly enhance the performance of the spiral wound membrane (SWM) module. This study provides an insight for the design of feed spacer to optimize the performance of reverse osmosis membrane module.

A reliable, practical and cost-effective portable wireless potentiostat for mobile chemical sensing and biosensing

Abstract Traditional electrochemical workstations are costly, complex, bulky, and primarily used in laboratories. This study develops a reliable, practical, and cost-effective portable wireless potentiostat to achieve real-time detection on-site and overcome the limitations of traditional electrochemical workstations. The system employs a general-purpose microcontroller unit (MCU), a dual-mode Bluetooth module and cost-effective multi-analog-to-digital converter (multi-ADC) to achieve differential sampling of the LMP91000. The system is equipped with buttons and OLEDs, enabling connection to mobile phones and computers for in-depth data analysis or independent operation. The system was successfully tested with [Fe(CN)6]3-, C6H12O6, and C3H6O3 solutions at concentrations ranging from 0 to 20 mM. The goodness-of-fit (R²) values are 0.984, 0.996, and 0.998, respectively. The average relative standard deviation of the three blank solutions is approximately 3.22%. The detection limits measured (0.003, 0.009, and 0.005 mM) are all lower than the minimum detection concentration (0.2, 0.1, and 0.1 mM). The coefficient of variation for repetitive experiments is less than 5.53%. The device accurately executed chronoamperometry (applied voltage range is ± 1.2 V, current range is ± 882 μA, accuracy is ± 1 %) with high sensitivity and good repeatability. Based on this circuit, a lactic acid detector and a urine glucose detector were developed, which work stably and support long-term operation, proving the stability and reliability of the circuit. Compared to commercial electrochemical workstations, PWES offers remarkable advantages in cost (< $6.4), size (41.5 mm × 76.5 mm), and practicality, making it suitable for a range of applications, including biomedical analysis, food safety, environmental monitoring, and smart wearables.

Synergistic effects of NiPtCo/Ti0.7W0.3O2 hybrid electrocatalysts for accelerating formic acid electro-oxidation performance.

We herein report the fabrication strategy of a robust catalyst for the formic acid electro-oxidation reaction (FAOR) via combining the advantages of a TiO2-related support and the synergistic effects of NiPtCo alloy. With the predominant dehydrogenation pathway, the NiPtCo/Ti0.7W0.3O2 catalyst shows remarkable FAOR mass activity and specific activity of 0.45 A mgMetal-1 and 1.25 mA cm-2, being 3.75- and 4.81-time higher than those of the commercially available Pt/C, respectively. The as-made FAOR electrocatalyst shows superior CO-tolerance and electrocatalytic stability during long-term operation conditions due to the synergistic contributions of each component in the overall catalyst system.

Deep learning-based multilabel compound-fault diagnosis in centrifugal pumps

In this study, the issue of centrifugal pumps used in marine engineering is addressed, as they are susceptible to malfunction owing to long-term operation in highly corrosive seawater and extreme weather conditions, resulting in operational interruptions and safety risks. We propose a high-precision intelligent fault-diagnosis method for multiple fault types based on deep learning. In this method, continuous wavelet transform is firstly employed to extract signal time–frequency domain features. Subsequently, the Swin transformer model is used to process the wavelet time–frequency images converted from signals. Finally, multilabel classification methods are combined to diagnose various complex faults. The effectiveness of the proposed method is validated using a dataset obtained from simulation experiments pertaining to centrifugal-pump faults. The results show that the proposed method achieves 100% accuracy in diagnosing 27 types of faults and provides excellent diagnosis even under limited compound-fault samples, thus offering an efficient and practical method for fault diagnosis in centrifugal pumps used in marine engineering.

Experimental Studies of Low-Reinforced Concrete Structures Containing Inter-Bay Construction Joints Strengthened with Prestressed Basalt Composite Reinforcements and External Transverse Reinforcements

During the long-term operation of main run-of-river head powerhouses for hydroelectric power plants, technical changes that deteriorate the operational properties of their reinforced concrete structures can occur. Therefore, in order to substantiate the application of prestressed basalt composite reinforcements to strengthen reinforced concrete hydraulic structures in operation, a set of computational and experimental studies was carried out, taking into account their characteristic features. After 4 years of ageing, the serviceability and reliability of the beams with prestressed basalt composite reinforcements were demonstrated through stabilisation of the prestress losses and the values obtained for bearing capacity, deflection, and the width of the opening of the inter-bay construction joints and the deformations of the metal reinforcements and the basalt composite reinforcements. The bearing capacity of the investigated reinforced concrete beams reinforced with external transverse reinforcements was increased 1.4–2.5 times over that of the variants reinforced with longitudinal prestressed basal composite reinforcements. Furthermore, in this study, the impacts of static loads and seismic effects with a magnitude greater than 8 on the run-of-river hydroelectric power plant powerhouse were calculated based on dynamic design theory. Regarding applications to hydroelectric power plant structures and constructions, for which it is not always possible to determine the location of compressed or tensile zones during their operation nor under seismic action, our research results are suggestive of a reasonably positive effect.

One-pot fabrication of high-entropy heterostructure cathode materials with excellent anti-poisoning properties in solid oxide fuel cells

Degradation of cathode performance in solid oxide fuel cells (SOFCs), which is poisoned by atmospheric CO2 and volatilized Cr from steel connecting plates, is a key factor limiting the long-term stable operation. In this work, high entropy heterostructure La0.5Ba0.5Fe0.2Co0.2Ni0.2Cu0.2Mn0.2O3-δ@Ba2CuO3 (HE-LBF@BCO) is designed and prepared by the one-pot method to improve the anti-poisoning ability of the electrode against CO2 and Cr. Meanwhile, the Ba2CuO3 (BCO) heterostructure formed by self-assembly using atomic size effect improves the electrochemical performance. The peak power density with HE-LBF@BCO cathode reaches 789 mW cm−2 at 800 °C with the polarization impedance of 0.34 Ω cm2. To further extend the three-phase interface and enhance oxygen catalytic activity, for HE-LBF@BCO-Gd0.1Ce0.9O2-δ(GDC) composite cathode, the peak power density reaches 789 mW cm−2 and the polarization impedance decreases to 0.16 Ω cm2 at 800 °C, exhibiting a brilliant application potential of the high entropy cathode. More importantly, HE-LBF@BCO-GDC shows an outstanding stability both in CO2 and Cr-containing atmosphere. After testing in Cr-containing atmosphere at 0.8V, the current density of the single cell with HE-LBF@BCO-GDC cathode decreases from 250.86 to 208.64 mA cm−2 at 700 °C. The results confirm the design of high-entropy heterojunction electrode materials provides a new strategy to address the enhancement of SOFC performance.

ASSESSMENT OF THE PROBABILITY OF OCCURRENCE OF EMERGENCY SITUATIONS DURING OPERATION OF THE PYROLYSIS PLANT

The article discusses the issues of reliability and safety of operation of a pyrolysis plant for the disposal of used tires, which, in the context of an increasing volume of waste and the need for their effective disposal, is an urgent topic. The problem statement is related to the identification of factors affecting the reliability of the installation and the development of methods to prevent emergencies.The purpose of the study is to analyz the reliability of the pyrolysis plant and develop recommendations for its improvement. To achieve this goal, the causes and probabilities of failures of system elements are investigated, an analysis using the failure tree method is carried out. This method made it possible to identify the weaknesses of the system and assess the probability of their failures, which is critical to prevent emergencies.An assessment of the reliability of the installation showed that the greatest contribution to the probability of accidents is made by a malfunction of the gas separation system. This element is the most vulnerable due to its complexity and importance in the pyrolysis process, as it is responsible for the safe and effective separation of pyrolysis products. Any malfunction of the gas separation system can lead to the accumulation of dangerous gases, increasing the risk of explosions and fires. The identified emergencies require special attention to the development of effective measures to minimize them.The article proposes methods to improve the reliability of the system, the main of which is the redundancy of the most vulnerable elements. This will significantly reduce the probability of failures and increase the overall reliability of the installation. In addition, it is recommended to carry out regular inspections and maintenance of all elements of the system. These measures will help to identify and eliminate potential malfunctions in a timely manner, which will significantly reduce the likelihood of failures that can lead to emergencies.Thus, ensuring the reliability and safety of a pyrolysis plant for the disposal of used tires requires an integrated approach. Enabling redundancy of vulnerable elements and regular maintenance will minimize the likelihood of failures that can lead to emergencies and guarantee stable and safe operation of the system. These measures will not only increase the efficiency of disposal, but also ensure reliable and long-term operation of the installation.This article focuses on the importance of identifying vulnerable elements of the system and conducting regular maintenance to improve the reliability and safety of operation of the pyrolysis plant.

Dynamic liquid level prediction for multiple oil wells based on transfer learning and multidimensional feature fusion network

Abstract Accurate prediction of the dynamic liquid level (DLL) in oil wells is crucial for the intelligent optimization of pumping systems. It provides real-time insights into the operational conditions of the pumping system but also supports the optimization of operational parameters with data. However, due to the long-term operation of oil wells and their complex internal environments, direct measurement of the DLL is challenging, leading to low reliability of the obtained data. Therefore, this paper conducts an in-depth analysis of the parameters involved in the pumping process, identifies the model’s input features, and develops a DLL prediction model for multiple wells based on multidimensional feature fusion (MFF). This model captures the characteristics of DLL changes and the diversity of input features. To address the issues of slow model training and low prediction accuracy caused by insufficient datasets in practical applications, this paper integrates transfer learning (TL) techniques. It proposes a new model, the DLL model for multiple wells based on TL and multidimensional feature fusion (TMFF). Initially, the Euclidean distance and maximum mean discrepancy methods are employed to verify the feature similarity between the source and target domains, using highly similar DLL data as experimental data. By combining TL techniques with the MFF model, the TMFF model is established. The model’s capabilities are validated using field-collected data with broad representativeness. Experimental results demonstrate that the proposed MFF model possesses high accuracy and generalization capability. Additionally, the TMFF model effectively resolves the issue of insufficient data during model training. In summary, the methods proposed in this paper can provide accurate DLL data for practical applications in intelligent oilfields.

New insight in the biotreatment of produced water: Pre-oxidation paves a rapid pathway for substrate selection in microbial community

The deep treatment of produced water (PW) had emerged as a formidable challenge due to the coexistence of hydrocarbons, surfactants, ammonium nitrogen, and other refractory organics. On the basis of the pre-oxidation coupled heterotrophic ammonia assimilation (PHAA) system constructed in previous research, this work refined the catalyst selection and reduced the hydraulic retention time. The stable running PHAA system removed 96.2 % of total organic carbon (TOC). The study simulated the effects of organic loading fluctuations on the system and dissected the mechanism of pre-oxidation process and its contribution to microbial community. Pre-oxidation significantly improved the ability of microbial community to handle loading shocks and improved organic degradation efficiency in PW during long-term reactor operation. The PHAA process effectively removed medium to long chain alkanes above C24 in PW and proposed potential degradation pathways and direction. The determination of hydrocarbon enzymes activity showed that pre-oxidation changed the substrate selection, making more aldehydes available as auxiliary carbon sources for microorganisms. Pre-oxidation also enriched and preserved microbial diversity, facilitating the accumulation of functional microorganisms in the PHAA process.

Construction of electron-deficient Co on the nanoarrays enhances absorption and direct electron transfer to accelerate electrochemical nitrate reduction

Electrochemical nitrate reduction is a promising remediation strategy for nitrate-contaminated wastewater treatment, in which nitrate adsorption is a prerequisite step in the overall process. Herein, the iron-induced cobalt phosphide was grown in situ on porous nickel foam (Fe-CoP/NF) for the electrochemical nitrate reduction. Structural characterization verified doping of Fe and the uniform nanotube arrays of Fe0.03CoP/NF. Remarkably, the Fe0.03CoP/NF exhibited a high efficiency nitrate removal efficiency (99.3 %) and excellent ammonia selectivity (100 % selectivity and 0.485 mg·h−1cm−2 NH3 yield rate). Both experimental and theoretical results reveal that Fe doping alters the local charge distribution of the Co active centers to form electron-deficient Co. The Co electron-deficient regions were constructed due to the difference in electronegativity between Co and Fe. Furthermore, the formation of electron-deficient centers facilitates the reduction of charge transfer resistance. In particular, Fe0.03CoP/NF maintained an excellent conversion efficiency of nitrate to N2 (99.8 %) with 60 mM Cl−, and the selectivity of N2 is maintained above 99.1 % during long-term operation. This system possesses a low electrical consumption of 1.79 kWh·molN−1. This study designed an enhanced electrocatalyst through enhanced nitrate absorption and direct electron transfer strategies, thus providing a promising and low-power consumption approach for addressing nitrate pollution.

Nano-Fe3O4/FeCO3 modified red soil-based biofilter for simultaneous removal of nitrate, phosphate and heavy metals: Optimization, microbial community and possible mechanism

The pollution of nitrogen, phosphorus and heavy metals in surface water is becoming more and more serious, affecting the safety of water quality. In this study, three biofilters were constructed using iron-modified red soil-based filler carriers (RSC, nano-Fe3O4@RSC, and FeCO3@RSC) combined with strain Zoogloea sp. ZP7 to simultaneously remove nitrate (NO3--N), phosphate (PO43--P), copper (Cu2+), and zinc (Zn2+). The long-term operation results showed that the three groups of biofilters could remove 85.0 %, 90.0 %, and 89.8 % of NO3--N, respectively. Furthermore, the addition of iron compounds enhanced the removal of PO43--P and the resistance to the stress of Cu2+ and Zn2+ in the biofilter. The analysis illustrated that iron modification improved the redox activity and zeta potential of RSC surface. The secondary structure analysis of the protein showed that the microbial secreted proteins were more compact on the surface of the iron-modified RSC, which facilitated the formation of biofilm on the carrier surface. In addition, the iron-modified RSC-based biofilter also showed excellent NO3--N and PO43--P removal efficiency in the treatment of actual surface water. The microbial community analysis results showed that Zoogloea became the dominant species in the biofilter. On the other hand, the presence of iron-reducing bacteria and the expression iron cycle-related genes may contribute to denitrification under low nutrient conditions.

A deeper investigation of membrane fouling in anaerobic membrane bioreactors for wastewater treatment: Influencing factors and fouling layer characteristics

Identifying the core parameters affecting membrane fouling and analyzing fouling layer characteristics are crucial for membrane fouling mitigation of anaerobic membrane bioreactors (AnMBRs). This study investigated the influence of various operating parameters on membrane fouling and the characteristics of different fouling layers. The ratio of flux to specific gas demand per unit of membrane area (SGD) was proposed as a key parameter for membrane fouling control and was applicable under various flux, SGD, and sludge concentration conditions. The membrane resistance and specific filtration resistance of foulants at high flux and sludge concentration reached 1.56 × 1012 m−1 and 3.56 × 1015 m−1/kg, respectively. Solid foulants accumulated on the membrane surface during rapid fouling stage. Protein-like pollutants accounted for a higher proportion (85%) of soluble foulants on the membrane surface. Humic acids were enriched on the cake/gel layer and the longitudinal enrichment process from the cake layer to the gel layer was uneven. Proteocatella (>45%) at the phylum level, Desulfovibrio (>3.1%), Syntrophobacter (>2.8%), and Treponema (>0.25%) at the genus level colonized in the gel layer and were the pioneers of membrane biofouling. Their enrichment on the membrane surface was primarily based on their own characteristics and was less sensitive to the operating conditions of AnMBRs. Therefore, this study provides a deeper understanding of membrane fouling formation process, which contributes to the long-term stable operation of AnMBR and scales up its engineering application.

Fairness in online vehicle-cargo matching: An intuitionistic fuzzy set theory and tripartite evolutionary game approach

This paper explores the concept of fairness and equitable matching in an on-line vehicle-cargo matching setting, addressing the varying degrees of satisfaction experienced by shippers and carriers. Relevant indicators for shippers and carriers in the on-line matching process are categorized as attributes, expectations, and reliability, which are subsequent quantified to form satisfaction indicators. Employing the intuitionistic fuzzy set theory, we devise a transformed vehicle-cargo matching optimization model by combining the fuzzy set’s membership, non-membership, and uncertainty information. Through an adaptive interactive algorithm, the matching scheme with fairness concerns is solved using CPLEX. The effectiveness of the proposed matching mechanism in securing high levels of satisfaction is established by comparison with three benchmark methods. To further investigate the impact of considering fairness in vehicle-cargo matching, a shipper-carrier-platform tripartite evolutionary game framework is developed under the waiting response time cost (WRTC) sharing mechanism. Simulation results show that with fairness concerns in vehicle-cargo matching, all stakeholders are better off: The platform achieves positive revenue growth, and shippers and carriers receive positive subsidy. This study offers both theoretical insights and practical guidance for the long-term and stable operation of the on-line freight stowage industry.

Component analysis of a 25-cell stack following 6.7 kh of high temperature electrolysis

The demonstration of relevant lifetimes for solid oxide electrolysis stacks is an underlying necessity to the rapidly industrializing technology. Following a 6.7 kh test of a 25-cell stack, post-mortem analyses of cells, seals, and interconnects were carried out to assess their long-term stability.Micrographs of cells aged in nominal conditions highlighted Ni depletion in the functional layer, SZO interlayer growth, and the presence of a Sr-rich secondary phase. The microstructure of glass-ceramic seals remained for the most part stable following operation. In addition, in spite of a thin design and the absence of coating, interconnects showed remarkable stability, with limited chromia growth and Cr depletion. Notably, no Cr poisoning could be detected in the cell functional layer.In view of the results, the loss of tightness of the H2 compartment, due to initial defects or caused by failures, is seen as the most immediate threat to this stack long-term operation.