Pressure Flow Research Articles

Coupled Effects of Fault-Related Groundwater Flow and Pore Water Pressure: Unraveling the Mechanisms of Deformation and Failure in Gentle Slopes

Coupled Effects of Fault-Related Groundwater Flow and Pore Water Pressure: Unraveling the Mechanisms of Deformation and Failure in Gentle Slopes

Prospects of cold plasma in enhancing food phenolics: analyzing nutritional potential and process optimization through RSM and AI techniques

Consumption of plant-based food is steadily increasing and follows an augmented trend owing to their nutritive, functional, and energy potential. Different bioactive fractions, such as phenols, flavanols, and so on, contribute highly to the nutritive profile of food and are known to have a sensitivity toward higher temperatures. This limits the applicability of traditional thermal treatments for plant products, paving the way for the advancement of innovative and non-thermal techniques such as pulsed electric field, microwave, ultrasound, cold plasma, and high-pressure processing. Among these techniques, cold plasma would be an operative choice in plant-based applications due to their higher efficacy, greenness, chemical exclusivity, and quality retention. The efficiency of the plasma process in ensuring the bioactive potential depends on several factors, such as feeding gas, input voltage, exposure time, pressure, and current flow. This review explains in detail the optimization of process parameters of the cold plasma technique, ensuring greater extractability or retention of total phenols and antioxidant potential. Response surface methodology (RSM) is one of the common techniques involved in the optimization of these course factors. It also covers the convention of artificial intelligence-based methods, such as artificial neural networks (ANN) and genetic algorithms (GA), in evaluating the data on process parameters. The review critically examines the strengths of each optimization tool in determining the optimal process parameters for maximizing phenol retention and antioxidant activity. The ascendancy of these techniques was mentioned in the studies regarding fruit, vegetables, and their products, and they can also be applied to other food products.

Convolutional neural network for determining the flow field around an airfoil and blunt-based models

The convolutional neural network is widely applied in the classification of images and medicine. Some current networks are used in aerospace engineering and show a high potential in determining aerodynamic forces and flow fields. This article constructs a convolutional neural network for predicting pressure and velocity fields around a two-dimensional aircraft wing model (airfoil model). Training data is computed using the Reynolds-averaged method, and then extracted, focusing on the flow around the wing. Input data includes geometric parameters, and airfoil inlet velocity, and output data includes pressure field and flow velocity around the airfoil. The convolutional neural network is based on improving the U-Net network model, commonly used in medical applications. The results show that the convolutional neural network accurately predicts flow around the airfoil, with an average error below 3%. Therefore, this network can be used and further developed to predict flow around the wing. The network is then applied to predict the pressure and pressure fields around a blunt-based model with different aspect ratios. The main feature of the flow can be extracted from the network. Results related to pressure distribution, velocity, and method error are presented and discussed in the study. This study also suggests improving the network and applying it to pressure and velocity fields in aerospace engineering

Oxidative Destruction of p‐Chloroaniline in a Dielectric Barrier Discharge at Atmospheric Pressure in Oxygen

ABSTRACTThe paper presents the results of studies of the kinetics of decomposition of an aqueous solution of p‐chloroaniline (PCA) under the action of a dielectric barrier discharge at atmospheric pressure in an oxygen flow. The range of PCA concentrations was 10–150 mg/L, and the power density was 1.3 W/cm3. It was found that the decomposition of PCA proceeds formally according to the 1st kinetic order equation with a rate constant of (3.1–1.1) s‐1. The energy yield of decomposition (number of decomposed molecules per 100 eV of input energy) was 0.071–0.38. Data on the kinetics of the formation of degradation products (NH4+, NO2−, NO3−, Cl−, CO, CO2, carboxylic acids, aldehydes), as well as the results of biotesting of treated solutions are presented.

An Analysis of the Effect of Cavitation on Rotor–Stator Interaction in a Bidirectional Bulb Tubular Pump

This study delves into rotor–stator interaction within a bidirectional bulb tubular pump under cavitation conditions. Using pressure pulsation tests on a model pump and numerical simulations performed with ANSYS CFX software, we analyzed pressure pulsation and flow field data across three distinct flow rates and multiple cavitation numbers. Both time-domain and frequency-domain analyses were conducted to examine the patterns of pressure pulsation influenced by flow rates and cavitation numbers at various monitoring locations. A numerical flow field analysis further validated the findings. The results reveal that rotor–stator interaction manifests in the vaneless spaces of the pump during cavitation. The onset of cavitation alters the amplitudes of dominant frequencies at different flow rates. Near the guide vane and impeller, the dominant frequencies shift toward the impeller frequency and guide vane frequency, respectively. Under low-flow conditions, the rotor–stator interaction effect is more conspicuous due to the deteriorated flow pattern. Pressure pulsations are more strongly influenced in the front vaneless space (FVP) than in the rear vaneless space (RVP). This difference arises because the front guide vane destabilizes rather than stabilizes the flow pattern, worsening the rotor–stator interaction. Additionally, the FVP is less affected by the impeller than the RVP, further amplifying the influence of rotor–stator interaction on pressure pulsation. These findings provide a theoretical foundation for mitigating the effects of rotor–stator interaction on the operational stability and efficiency of bidirectional bulb tubular pumps.

Experimental investigation and optimization of process parameter of abrasive water jet machining (AWJM) on D2 steel

Abrasive water jet machining (AWJM) is the most significant hybrid unconventional machining technique for its exceptional material removal rate (MRR) and surface quality for any type of brittle, ductile, and composite materials with a higher level of precision and accuracy. It has great flexibility in machining for producing complex-shaped parts that can be used in automobile, marine, aerospace, and chemical industries. This study focuses on the application of AWJM for cutting of D2 steel components using silicon carbide (SiC) abrasives. The experiments are conducted following the Box-Behnken Design (BBD) of response surface methodology (RSM) as the design of experiment (DOE) by considering pressure (P), traverse speed (TS), and abrasive flow rate (AFR) as the input factors each with three different levels in obtaining the corresponding outputs, namely MRR and surface roughness (Ra). Finally, the multicriteria decision-making (MCDM), Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method, is applied to optimize the output values as MRR of 2.757 mm3/sec, and Ra of 1.014 µm.

Increased resting heart rate indicates high-workload hearts with augmented aortic hydraulic power in hypertensive pigs.

Clarifying the inceptive pathophysiology of hypertensive heart disease helps to impede the disease progression. Through coarctation of the infrarenal abdominal aorta (AA), we induced hypertension in minipigs and evaluated physiological reactions and morpho-functional changes of the heart. Moderate aortic coarctation was achieved with approximately 30 mmHg systolic pressure gradient in minipigs. Hypertension was assessed by pressure increment of the carotid artery. Perioperative heart rate (HR) was recorded. We measured aortic flow rate and pressure proximal to coarctation to calculate hydraulic power, an indicator for cardiac workload, and resistance. The hearts harvested at sacrifice were examined for myocardial hypertrophy, fibrosis, and dysfunction. The parameters capable of indicating high-workload heart and their prediction effectiveness were determined by cluster and receiver operating characteristic (ROC) analyses. Prolonged AA coarctation for 8-12 weeks induced hypertension in a portion of minipigs. The cluster of minipigs exhibiting increased aortic hydraulic power displayed hypertension and mean HR elevation without changing arterial resistance. Notably, the blood pressure and HR were measured under full anesthesia, equivalent to resting status. Myocardial hypertrophy was not detected at the tissue, cellular or molecular levels. Expression of biomarkers for cellular stress and heart failure didn't increase except for heat shock protein 40. ROC analysis showed that aortic hydraulic power, resting HR, and mean blood pressure, but not arterial resistance, can serve as the indicators for high-workload hearts. These results suggested that resting HR increase in hypertensive pigs indicates hearts with high workload. Heart failure may develop without appropriate treatment.

Achieving Complex‐Shaped Stainless Steel Parts via a Facile Net‐Shaping Method

A facile method named metal compression molding (MCM) is developed using the 17‐4PH stainless steel feedstock derived from powder injection molding. Complex golf‐club featuring intricate surfaces, thin walls, and thick walls are fabricated via MCM. Simulation software Moldflow is used to study the flow behavior, pressure, and shear rates of feedstock at 180, 190, and 200 °C. The results show that most of the feedstock maintain their original position and a small amount of feedstock flow to fill mold cavity; viscosity decreases with increasing temperature, while stress and shear rate reach their maximum and minimum, respectively, at 190 °C. The MCM process demonstrates the ability to form the golf‐club head, and samples with a smooth surface are obtained at the pressing temperature of 190 °C. The simulated stress distribution during MCM influences the density and mechanical properties of the sintered golf‐clubs, higher stress correlates with better performance. High‐density (97.89 ± 0.08) 17‐4PH stainless steel shows excellent mechanical properties, with an ultimate tensile strength of 999.5 ± 7.0 MPa and an elongation of 14.15% ± 0.41%.

Towards constructing a generalized structural 3D breathing human lung model based on experimental volumes, pressures, and strains.

Respiratory diseases represent a significant healthcare burden, as evidenced by the devastating impact of COVID-19. Biophysical models offer the possibility to anticipate system behavior and provide insights into physiological functions, advancements which are comparatively and notably nascent when it comes to pulmonary mechanics research. In this context, an Inverse Finite Element Analysis (IFEA) pipeline is developed to construct the first continuously ventilated three-dimensional structurally representative pulmonary model informed by both organ- and tissue-level breathing experiments from a cadaveric human lung. Here we construct a generalizable computational framework directly validated by pressure, volume, and strain measurements using a novel inflating apparatus interfaced with adapted, lung-specific, digital image correlation techniques. The parenchyma, pleura, and airways are represented with a poroelastic formulation to simulate pressure flows within the lung lobes, calibrating the model's material properties with the global pressure-volume response and local tissue deformations strains. The optimization yielded the following shear moduli: parenchyma (2.8 kPa), airways (0.2 kPa), and pleura (1.7 Pa). The proposed complex multi-material model with multi-experimental inputs was successfully developed using human lung data, and reproduced the shape of the inflating pressure-volume curve and strain distribution values associated with pulmonary deformation. This advancement marks a significant step towards creating a generalizable human lung model for broad applications across animal models, such as porcine, mouse, and rat lungs to reproduce pathological states and improve performance investigations regarding medical therapeutics and intervention.

Computational Fluid Dynamics (CFD) Modeling of Material Transport through Triply Periodic Minimal Surface (TPMS) Scaffolds for Bone Tissue Engineering.

Cell-laden, scaffold-based tissue engineering methods have been successfully utilized for the treatment of bone fractures. In such methods, the rate of scaffold biodegradation, transport of nutrients, and removal of cell metabolic wastes are critical fluid-dynamics factors, affecting tissue regeneration. Therefore, there is a critical need to identify the underlying material transport mechanisms associated with stem cell-driven, scaffold-based bone tissue regeneration. The objective of the work is to establish computational fluid dynamics (CFD) models to identify the consequential mechanisms behind internal and external material transport through/over porous bone scaffolds designed based on the principles of triply periodic minimal surfaces (TPMS). In this study, advanced CFD models were established based on ten TPMS designs for analyzing (i) single-unit internal flow, (ii) single-unit external flow, and (iii) cubic, full-scaffold external flow. The main fluid characteristics influential in bone regeneration, including flow velocity, pressure, and wall shear stress (WSS), were analyzed to assess material transport internally through and externally over the TPMS designs. Schwarz Primitive (P) appeared to have the lowest level of flow pressure and WSS (desirable for development of bone tissues). An analysis of streamline velocity exhibited an increase in velocity togther with a depiction of turbulent motion along the curved surfaces of the TPMS designs. Besides, pressure buildup was observed within the inner channels of almost all the TPMS designs. Overall, the outcomes of this study pave the way for optimal design and fabrication of bone-like tissues with desirable medical properties.

High-resolution hemodynamic estimation from ultrafast ultrasound image velocimetry using a physics-informed neural network

Objective.Estimating the high-resolution (HR) blood flow velocity and pressure fields for the diagnosis and treatment of vascular diseases remains challenging.Approach. In this study, a physics-informed neural network (PINN) with a refined mapping capability was combined with ultrafast ultrasound image velocimetry (u-UIV) to predict HR hemodynamic parameters. Specifically, the Navier-Stokes equations were encoded into the PINN to dynamically optimize the network performance under physical constraints, and a refined mapping network was added at the input to achieve data refinement. During the prediction of HR ultrasound hemodynamic parameters, only the sparse spatial coordinates in the time series were input into the PINN, and the velocity vectors generated from the u-UIV were used together with physical residuals to enhance the physical correctness of HR predictions during the iterative process.Main results.The performance of the refined mapping network was validated via simulations, with a 1.9-fold increase in the radial resolution and a 2.5-fold increase in the axial resolution. HR velocity field estimation fromin vitroandin vivodata showed good agreement with theoretical values and u-UIV measurements, with micrometer-level spatial resolution (88µm×115µm for straight vessel, 75µm×120µm for stenotic vessel and 63µm × 79µm forin vivodata), while the pressure field could be inferred from physical laws.Significance.The proposed method performs well when few data samples are available and has the potential to assist in the clinical diagnosis of vascular diseases.

In Vitro Analysis of Pressure Resistance in the Paul Glaucoma Implant and Ahmed ClearPath 250 With and Without Polypropylene Thread Inside the Tube.

Pressure resistance characteristics of the Paul glaucoma implant (PGI) and Ahmed ClearPath 250 (ACP), with and without the insertion of polypropylene thread in their tubes, were evaluated. The in vitro flow pressure was evaluated at varying flow rates, both with and without threads (6-0 for PGI and 4-0 or 3-0 for ACP). Cross-sectional areas of the tube lumen and thread were measured to calculate pressure resistance using the Hagen-Poiseuille equation. For the PGI without the thread, the pressure remained relatively low and constant across all flow rates. In contrast, with the insertion of a 6-0 thread, there was a significant increase in pressure resistance, with the pressure increasing from 7.5mmHg at 1 µL/min to 43.8 mmHg at 5 µL/min. For the ACP, the pressure resistance remained relatively constant across all flow rates without a thread and with either 4-0 or 3-0 threads. However, the pressure was higher with 3-0 threads compared with a 4-0 thread. The actual measured pressures agreed well with theoretical values in the no-thread conditions, but were consistently higher than the theoretical values in the threaded conditions. Inserting polypropylene threads into the tubes of nonvalved glaucoma drainage devices significantly affects pressure resistance with various degree. PGI with a 6-0 polypropylene thread may not require external tube ligation to prevent hypotony, whereas ACP with a 4-0 thread likely requires additional ligation. Using a 3-0 thread in ACP may enhance pressure resistance sufficiently to avoid tube ligation, but this requires careful clinical consideration.

Pharyngeal airway dimensions and adipose distribution in the minipig.

To evaluate the pharyngeal airway dimensions and regional pharyngeal adipose distribution in the young adult minipig model. Eight 7-8-months-old Yucatan minipigs, half male and female, were sedated and placed prone to scan the pharyngeal region. Magnetic resonance imaging (MRI) was performed using dynamic turbo-field echo (TFE)-sequence with respiratory gating and adipose-weighted sequence. Respiratory airflow velocity, pressure, and volume were also recorded. The sizes of velopharyngeal and oropharyngeal airway, and retroglossal areas were measured coronally during inspiration and expiration. The airway volumes from the nasal cavity to the retroglossal space were segmented, reconstructed, and evaluated in sagittal views. The adipose distribution in the tongue base, soft palate, pharyngeal wall, tongue body, and masseter muscle (reference) were segmented and measured in sagittal and coronal planes. The velopharyngeal and oropharyngeal areas were larger in inspiration than in expiration. These areas were also larger than that in the retroglossal space (p<0.05). The nasal cavity showed a larger volume than that of the pharyngeal regions (p<0.05). The adipose distribution was larger in the posterior region of the tongue base and anterior soft palate, both larger than the masseter muscle (p<0.05). The larger oropharyngeal dimensions and increased adipose distribution in the tongue base contribute to the functional morphology of the pharyngeal airway in the healthy minipig. These data provide the baseline for further analysis in enlarged and reduced tongue base minipig models.

Internal flow effect of a flexible riser system for a floating offshore wind turbine with on-board carbon dioxide capture

This paper designs a flexible riser for transporting carbon dioxide (CO2) off a floating offshore wind turbine (FOWT)-powered CO2 capture platform, and analyzes the internal flow-induced effects caused by the CO2 on the flexible riser. Internal effects on flexible risers due to the pressurized and internal dynamic flow are a well-studied problem in offshore oil and gas (O&G) applications, which typically requires the use of tools capable of representing their pressurized contents and flows. However, because the flow rates and pressure conditions expected from individual FOWT-CO2 capture platforms are much lower than those used in O&G installations, we studied the importance of internal flow effects on riser dynamics. To determine their relevance, we designed and modelled the flexible riser in OrcaFlex™ with different design pressure and flow conditions under normal and extreme environmental events. The results indicate that the riser’s effective tension and curvature are not significantly affected by internal flow effects, but differences were observed in the von Mises stress arising from the shear stress, which is a purely hydrostatic term. As such, as long as the shear term is properly accounted for, these results enable future work to utilize simplified models for the flexible riser system, similar to models for dynamic power cables employed in FOWT farms. This simplification allows us to design and analyze the whole FOWT-CO2 system alternatively with lower fidelity and open-source offshore wind turbine simulation tools, like OpenFAST, without overlooking relevant riser-dynamics phenomena.

Advanced Adiabatic Compressed Air Energy Storage Systems dynamic modelling: Impact of the heat storage device

Advanced Adiabatic Compressed Air Energy Storage (AACAES) is a technology for storing energy in thermomechanical form. This technology involves several equipment such as compressors, turbines, heat storage capacities, air coolers, caverns, etc. During charging or discharging, the heat storage and especially the cavern will induce transient behavior of operating points, notably temperature, pressure, and volume flow. In contrast, the optimal use of turbomachinery requires it to be as stationary as possible. AACAES technology therefore requires transient modelling to optimize its design. This paper presents a modular and adaptable numerical tool capable of simulating the dynamic behavior of different thermomechanical storage systems. This tool is then applied to an AACAES system to analyze the impact of various configurations on the variability of volume flow. The aim is to optimize Round Trip Efficiency (RTE) while limiting the maximum variation in volume flow. First, the effect of the size of fixed-bed Thermal Energy Storage (TES) is analyzed. Then, we analyze the behavior of the system with heat management based on a heat exchanger and a heat transfer fluid. In addition, the effect of adding pressure control at the cavern inlet/outlet on the two previous variants is studied.

Flow and heat transfer characteristics of a porous-coated cylinder under simultaneous wave and current forces at a high Reynolds number

In the present study, a two-dimensional finite volume method is used to simulate the heat transfer rate of a circular cylinder coated with different structures of porous materials at Re=4800. The incompressible uniform flow is associated with deep-water waves created by a flap-type wave maker to investigate the effects of simultaneous current and wave forces on the pressure coefficients, flow characteristics, and heat transfer rate of cylinders wrapped by various porous structures (S2, S3, S4, and S5) and different Darcy numbers (Da=10, 10−1, and 10−2). According to the results, the porous layer thickness (e*) affects the outer shape of the porous coating and alters the influence of wave–current interaction on the flow characteristic. Therefore, compared to the current case, the lift and drag forces in the wave–current case increase in S2, but decrease in other porous structures. Moreover, S5, with the thickest porous coating showed the maximum heat transfer rate. Porous materials with low permeability decrease the impact of e* on heat transfer. However, the vortex-shedding patterns with thermal plumes become stronger with decreasing the Darcy number. The heat transfer rate of porous structures increases by about 42% as Da decreases from 10 to 0.1, and another 37% increase is observed at Da= 0.01, resulting in a total rise of 96% in the average Nusselt number (Nu¯). Therefore, the gap between the heat transfer rate of porous structures and the smooth cylinder (S1) increases by about 17%, 79%, and 126% at Da= 10, Da= 0.1, and Da= 0.01, respectively.

Dual-stream gas targets for a point source of vacuum and extreme ultraviolet radiation supported by focused electromagnetic radiation

The article presents the results of visualization of two-stream gas targets for a point source of vacuum ultraviolet and extreme ultraviolet radiation. Measurements of the gas concentration spatial distribution were carried out using a Michelson interferometer. It is shown that adding a light gas to the peripheral channel significantly moves the region of breakdown concentration of injected gas through the central channel away from the nozzle, while maintaining the overall gas flow and background pressure.

Supersonic discharge of cold gas inflators into rectangular ducts

We discuss the supersonic discharge of cold gas inflators into confined ducts typical of curtain airbag inflation. The medium discharged from the cold gas inflators is helium. For this purpose, two different generic duct geometries are chosen to obtain one case without and one with wall interaction of the underexpanded jet. In the latter case, a so-called shock train develops, which dominates the flow topology. To quantify the flow field, time-resolved pressure transducers measure the static pressure at the duct walls and time-resolved particle image velocimetry measures the velocity in the far field of the underexpanded jet. Schlieren images illustrate the topology of the flow field. A simplified numerical model is then created that drastically reduces the required resources. The numerical model is verified against the experimental data and provides deeper insight into the outflow process. In particular, the interaction of the underexpanded jet with the duct walls and thus the resulting shock train are found to be sensitive. The numerical model can reconstruct the flow topology, pressure and velocity within acceptable limits. The experimental data and numerical results may serve as a basis for subsequent studies on airbag inflation or physically similar processes, especially for the validation of numerical methods.Graphical abstract

Turbulent flow pattern and flow resistance characteristics of cross flow over square-arranged tube bundles with different pitch to diameter ratios

Helical tube bundles are used in steam generators and intermediate heat exchangers of high temperature gas-cooled reactors due to their compactness and good thermal expansion adaptation performance. However, the characteristics of cross flow over inline tube bundles are sensitive to pitch to diameter ratios (S/D) and Reynolds numbers (Re), and the influence of S/D and Re variation on the flow patterns (especially wake patterns) and pressure drop coefficients (ξ) remains unclear. In the current investigation, the flow characteristics of tube bundles with S/D = 1.58 and 1.88 with various Re are investigated with the aid of wind tunnel experiments and large eddy simulations (LES). For the tube bundle with S/D = 1.88, the results of LES with periodical geometry align well with wind tunnel experiments, successfully predicting the decreasing recirculation region size as Re increases. In contrast, for the tube bundle with S/D = 1.58, the recirculation region size remains almost constant with varying Re, filling the space between two adjacent tubes even when Re = 36 000. However, the LES with periodical geometry only successfully predicts flow phenomena up to Re = 25 285. The wakes become oblique when Re = 36 000, which differs from experiments. Based on the force balance on the recirculation region, the pressure drop coefficient (ξ) of the cross flow over tube bundles is related to the size of the recirculation region. For the tube bundle with S/D = 1.88, the recirculation region size decreases as Re increases when Re ≥ 18 000, resulting in a larger flow cross section area in the main flow region. The increasing main flow cross section area leads to an increased pressure coefficient along the separation streamlines. Since the Reynolds normal and shear stresses cancel each other out, the increasing pressure coefficients along the recirculation region boundary lead to the increasing surface pressure coefficients in the rear side of the tube and ultimately lead to the ξ decrease from 0.26 to 0.24 when Re increases from 18 000 to 44 571. Conversely, when Re ≤ 10 285, the recirculation area fills the space between two adjacent tubes, so the ξ barely change with Re. For tube bundle with S/D = 1.58, the recirculation area fills the space between tubes even when Re ≥ 18 000, leading to almost the unchanged ξ (≈0.27) with Re. The higher ξ at Re = 10 285 is related to the bounding wall effects on the near wall tubes.

Validation of a post-processing methodology to readjust the voltage of a high-temperature PEM fuel cell according to the atmospheric pressure on a 2753h aging test at different constant currents

During an aging test of a high temperature proton exchange membrane fuel cell (HT-PEMFC) without exhaust pressure control loop, the anode and cathode pressures are dependent on variations in gas flow and atmospheric pressure. The voltage degradation rate is then impacted by atmospheric pressure variations. To extract the aging rate independently of the pressure, a possible solution is to estimate the voltage variation at a given pressure change. In this work, this voltage/pressure sensitivity was estimated in post-processing, by fitting regression planes (on measured voltage data) in the three dimensions: voltage, pressure, and time. It was applied on an aging test of 2753 h at 160 °C, at ambient pressure and at different constant currents (0.2, 0.4, and 0.6 A/cm2) which was carried out on an Advent Technologies Inc. PBI MEA of 45 cm2 active surface. The impact of varying atmospheric pressure on the calculation of degradation rates is then discussed and compared with another method developed in a previous work. It was found that a variation of 6 mV (2.4 % of initial voltage) at 1 A/cm2 during an aging test can be attributed to pressure variation alone, and not to cell degradation. Furthermore, it was observed that the voltage/pressure sensitivity is different depending on the period analyzed, at identical operating conditions (which would indicate that the dependence on pressure varies during aging). Indeed, at 0.2 A/cm2, the voltage response to a variation in pressure was quantified at approximately 50 μV/mbar and 80 μV/mbar at the start and end of life respectively. This method could therefore be used as an on-line diagnostic tool to monitor the fuel cell state of health.