Effects Of Operating Parameters Research Articles

Recent advancements in the synthesis of anion exchange membranes and their potential applications in wastewater treatment.

Water treatment procedures are increasingly utilized for resource recovery and wastewater disinfection, addressing the current challenges of clean water depletion and wastewater management. Various pollutants, including dyes, acids, pharmaceuticals, and toxic heavy metals have been released into the environment through industrial, domestic, and agricultural activities, posing serious environmental and public health risks. Addressing these issues requires the development of more effective waste treatment processes. Membrane-based treatment technologies offer significant advantages, including high efficiency, versatility, and cost-effectiveness, making them a promising solution for mitigating the impact of these pollutants. In view of this, the potential of ion exchange membranes (IEMs) is continuously increasing due to their advanced characteristics compared to conventional techniques. Anion exchange membranes (AEMs), a special class of IEMs, selectively allow anions to pass through their pores due to the positive charge on their surface. This selective passage aids in resource recovery and removing specific types of pollutants. This review covers preparation methods, modification techniques, and classification of AEMs. It offers a practical classification based on the method of synthesis and structural properties of AEMs. The water-based applications of AEMs including, electrodialysis, diffusion dialysis, and electro-electrodialysis for various wastewater treatments such as heavy metal recovery, dye removal, pharmaceutical removal, and acid separation, have been discussed in detail. Additionally, the effect of various operational parameters on the performance and SWOT (strengths, weaknesses, opportunities, and threats) analysis of AEMs in effluent treatment are presented. The review provides detailed insights into the current status, challenges, and future directions of AEM-based technologies, offering suggestions for future advancements.

Per-and polyfluoroalkyl degradation in a hybrid dielectric barrier discharge plasma and electrooxidation system through involving more reactive species by air and water circulation.

The presence of PFAS in water matrices has become a global environmental issue in the last half-century. Dielectric barrier discharge (DBD) and electrooxidation (EO) showed potential for PFAS degradation but have yet to find practical application due to relatively high energy consumption. In this study, a hybrid DBD-EO system for efficient degradation of PFAS was developed by involving more reactive oxygen, sulfate radicals (SO4•-) and nitrogen species (RONS). The results showed that using the hybrid DBD-EO system under optimal conditions (applied voltage = 6 kV and current density = 7.5 mA/cm2) could increase PFOA degradation efficiency from 65.0 % (DBD) and 62.5 % (EO) to 89.14 %. While the EE/O decreased from 67.0 kWh/m3 (DBD) and 47.82 kWh/m3 (EO) to 21.61 kWh/m3. In addition, the effect of operational parameters and water matrices revealed that the hybrid DBD-EO system had high potential for PFOA removal from water under various conditions. According to the EPR and DFT calculation results, integration of reactive species in EO (SO4•-, •OH, O2•-) and ONOOH) and DBD (•OH, O2•-, NO2•-, 1O2 and ONOOH) processes in the DBD-EO system led to efficient degradation of PFOA through a mechanism of decarboxylation/defluorination cycle. Our findings suggested the combination of DBD and EO is a promising approach for complete degradation of PFAS from water with low energy consumption and minimal environmental side effects.

Studies on Thermal Separation and the Effects of Geometrical and Operating Parameters on the Performance of Pressure Wave Refrigerators

Abstract Thermal separation in a pressure wave refrigerator (PWR) occurs primarily through the propagation of shock waves and reverse-moving rarefied waves produced by injecting a high-pressure gas into a low-pressure residual gas in a receiving tube or channel. The major advantages of PWRs are simple design, low cost, high reliability, low rotational speed, and efficiency comparable to the conventional turbo-expanders. The objectives of this work are to understand the thermal separation in PWRs and to study the effects of various geometrical and operating parameters on the performance of PWRs. Two-dimensional computational fluid dynamics (CFD) simulation using a finite volume method is adopted for this study. The results indicate that the temperature and pressure profiles of the fluid inside the receiving tube just before the discharge, in the region about half the tube length from the inlet nozzle, strongly govern the performance of a PWR. The operating frequency at which the isentropic efficiency attains the first peak value is determined in a generalized way. Within the chosen geometrical and operating parameters, the optimized tube length, operating frequency, and pressure ratio are 2 m, 50 Hz, and 2.5, respectively. The findings in this article will be useful in designing and operating PWRs optimally.

Starch-ZnCr/LDH Composite and ZnCr-LDH: Synthesis, Characterization, and Adsorption Efficiency to Remove Congo Red from Aqueous Solution

Background: To bring new materials with high performance, a large number of composites, among others, such as starch-laminated double hydroxides (starch/ZnCr-LDH), have been produced, which have shown significant adsorption predisposition to remove heavy metals and dyes. These LDHs display great adsorption potential due to their high anion exchange capacity, large surface area, and good thermal stability. Objective: This study aimed to develop starch-ZnCr-hydroxide composite (S/ZnCr-LDH) as a new material and investigate its performance in removing various anionic dyes compared to ZnCr- LDH. Methods: The starch-ZnCr-laminated double hydroxides (S/ZnCr-LDH) and ZnCr-LDH composites were prepared by the co-precipitation method and their structures were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential thermogravimetric/ thermal analysis (TG/DTA) Scanning electron microscopy (SEM), and Energy Dispersive Xrays Spectroscopy (EDX). Results: The effects of different operating parameters, such as pH, initial CR concentration, contact time, and adsorbent dose, on CR removal were studied. The results showed that the S/ZnCr- LDH composite is more efficient for CR removal, reaching 99% at pH 3, while ZnCr-LDH presented a removal efficiency of 90%. Isothermal data were processed according to the Langmuir, Freundlich, and Temkin models. According to the results, Langmuir's isothermal model best matched the experimental data, with a maximum adsorption capacity of 252. 92 and 236. 98 mg/g for S/ZnCr-LDH and ZnCr-LDH, respectively. The adsorption kinetics corresponded to the PSO model. CR dye molecules were adsorbed to different sites on the S/ZnCr-LDH composite based on various interactions, such as electrostatic interactions, hydrogen bonds, and Van der Waals forces. Conclusions: S/ZnCr-LDH composite displays the highest capacity to remove CR dye molecules compared to ZnCr-LDH.

Effect of design and operating parameters on solar still productivity

Effect of design and operating parameters on solar still productivity

Purification of mesenchymal stromal cell-derived small extracellular vesicles using ultrafiltration.

Mesenchymal stromal cell-derived small extracellular vesicles (MSC-sEVs) are pivotal for the curative effects of mesenchymal stromal cells, but their translation into clinical products is hindered by the technical challenges of scaled production and purification. Ultrafiltration, a pressure-driven membrane separation method, is well known as an efficient, scalable, and cost-effective approach for bioseparation. However, there has been little study so far that comprehensively evaluates the potential application of ultrafiltration for scaled sEV isolation and purification. In this study, the feasibility and effectiveness of ultrafiltration for MSC-sEV isolation and purification are studied, and the effects of key process design and operational parameters, including the membrane pore size, transmembrane pressure (TMP), stirring speed (shear rate), feed concentration, are quantified using a stirred cell setup. Results revealed that 500kDa molecular weight cut-off (MWCO) polyethersulfone membrane demonstrated superior suitability for MSC-sEV separation, yielding higher purity and productivity compared to 100 and 300kDa MWCO membranes of the same material. The MSC-sEV productivity and purity could also be improved by applying a moderate stirring speed and lower operational pressure, respectively. Isovolumetric diafiltration was incorporated to enhance the purity of MSC-sEVs, successfully removing about 99% of protein contaminants by six diafiltration volumes (DVs). Subsequently, a fed-batch ultra-diafiltration (UF/DF) process with optimised filtration parameters was developed and compared with the currently most used ultracentrifugation (UC) method, showing exceptional effectiveness and performance in the isolation of MSC-sEVs: it increased the recovery of MSC-sEV from 20.59% to 60.88% (about three folds increase) and nearly doubled the purity, while also reducing processing time from over 4h to 3.5h, with a potential further reduction to less than 2.5h through automation. The study concludes that ultrafiltration could be a promising method for both lab-scale preparation and industrial-scale manufacture of MSC-sEVs, offering advantages of high recovery, scalability, fast, and cost-effectiveness.

Effect of vehicle operating parameters on fuel consumption and the overall energy efficiency of the drive system

This article presents a research methodology that supplements known studies to solve the problem of a correct complementary analysis of vehicles with different drive units. This method can be used at the stage of selecting a car for specific tasks, as well as for in-service technical condition checks. A new method is proposed for analysing the impact of operating conditions on the mileage fuel consumption, unit fuel consumption and overall energy efficiency of vehicles. In the study, it was possible to determine the effect of changing the vehicle speed, road gradient angle and vehicle weight. Tests identifying fuel consumption and efficiency characteristics as a function of vehicle load were carried out using passenger cars with different drive designs. Carrying out tests under laboratory conditions on a chassis dynamometer bench enabled the precise determination of the change in operating conditions. The criteria adopted for the evaluation included fuel consumption and overall vehicle energy efficiency. The variable parameters included speed, vehicle weight, and the road gradient angle. The data for criteria calculation were acquired using a diagnostic tester with a functional parameter recording function. The application of the presented method enabled a comparison of the overall energy efficiency of two vehicles equipped with spark-ignition combustion engines, according to the criteria listed. The experiment showed that in a three-cylinder engine, unit fuel consumption is more sensitive to parameter changes under identical conditions (speed, vehicle weight, road gradient angle) than in a four-cylinder engine. To evaluate the drive units of the test vehicles, characteristics of changes in the overall energy efficiency were used as well. It was observed that in all testing variants, the value increased with increasing road gradient values, with the intensity of η increase not being constant. A car with a four-cylinder engine has a higher energy efficiency at low loads. The proposed methodology is relevant for evaluating vehicles with different drive systems (including hybrid) and adapting drive characteristics to the operating conditions. Partially the presented methodology can also be transferred to EV vehicles - in terms of energy efficiency.

Experimental investigation on swirling annular liquid film breakup characteristics of prefilming airblast atomizer

In order to further improve the understanding of the liquid film breakup characteristics of prefilming airblast atomizer, the effects of key operating parameters and structural parameters (swirl intensity, diameter and number of injection holes on pilot stage, length of pre-film lip and sleeve angle) on the liquid film pattern of prefilming airblast atomizer were investigated using the high-speed shadow method and the Otsu’s method. The mechanism of liquid film breakage was analyzed, the results show that, with the increase of fuel injection pressure, the spray morphology experiences “columnar-shaped”, “tulip-shaped” and “fully cone-shaped”. Meanwhile, the main fluctuation frequency of liquid film varies from 100.5 Hz in the “columnar-shaped” and “tulip-shaped” to 25.12 Hz in the “fully cone-shaped”. With increasing relative pressure drops of swirler, the film breakup length and film fluctuation frequency decrease, while the film fluctuation amplitude increases. An increase in inner-stage swirl intensities will lead to a reduction in the film breakup distance, while an increase in outer-stage swirl intensities will mainly lead to a larger spray angle. The increase of the diameter and number of injection holes and the length of pre-film lip leads to the rise of the liquid film breakup length, while the decrease of sleeve angle mainly leads to the rise of spray angle, which makes the liquid film more easily broken.

Effect of Operational Parameters and Iron Ore Tailings Properties on Filter Cake Porosity

Objective: By evaluating operational filtration conditions, chemical, mineralogical, and particle size properties of the tailings, the study aimed to identify critical variables affecting porosity and provide predictive models for optimizing dewatering operations. Theoretical Framework: This research builds upon existing theories of solid-liquid separation and dewatering processes in mineral processing. Key references include classical works on filtration dynamics, particle size distribution, and cake porosity characterization. The study addresses gaps in literature regarding the relationship between tailings composition and filtration results. Method: The Leaf Test method was employed on 33 fresh slurry samples from the Brucutu plant to simulate industrial filtration conditions. Filtration cycle parameters such as cake formation and drying times were standardized. Porosity was calculated using Grace's equation and correlated with characterization data, including mineralogical composition, true density, and particle size. Statistical methods such as clustering, regression, and Random Forest modeling identified key predictors of porosity. Results and Discussion: The results indicated that porosity correlates strongly with silica content and certain mineralogical attributes, such as the presence of martitic hematite and quartz. Cluster analysis revealed two sample groups with distinct filtration characteristics. While operational parameters showed limited impact on porosity, the statistical models highlighted the significance of ore composition. Research Implications: This research provides a foundation for optimizing iron ore tailings filtration by identifying the key variables influencing porosity. The findings support more efficient dewatering techniques, contributing to sustainable tailings management. Further, the development of predictive models aids industrial operations in minimizing risks associated with tailings disposal. Originality/Value: This study is among the first to integrate statistical modeling and mineralogical characterization in exploring filter cake porosity. The results offer novel insights into the optimization of solid-liquid separation processes in the mining industry.

Effects of Operation Parameters on Heat Transfer in Tubular Moving Bed Heat Exchangers: A CFD-DEM Study

Effects of Operation Parameters on Heat Transfer in Tubular Moving Bed Heat Exchangers: A CFD-DEM Study

A Refined Approach for Angle of Attack Estimation and Dynamic Force Hysteresis in H-Type Darrieus Wind Turbines

This study investigates the aerodynamic performance and flow dynamics of an H-type Darrieus vertical axis wind turbine (VAWT) using combined numerical and experimental methods. The analysis examines the effects of operational parameters, such as rotor solidity and pitch angle, on aerodynamic loads and flow characteristics, using a 2-D URANS simulation with the Transition SST model to capture transient effects. Validation was conducted in a low-turbulence wind tunnel to observe the impact of variable flow conditions. The LineAverage method for determining the angle of attack demonstrated strong correlations between rotor configuration and load variations, particularly highlighting the influence of blade number and pitch angle on aerodynamic efficiency. This research supports optimization strategies for Darrieus VAWTs in urban environments, where turbulent, low-speed conditions challenge conventional wind turbine designs.

Investigation on the effect of operational parameters in a microreactor system on the morphology and size distribution of thorium oxalate

Thorium oxide has recently garnered attention as a nuclear fuel due to the scarcity of uranium resources and the abundance of thorium resources, as well as its favorable thermal and neutronic properties. One of the most desirable characteristics of thorium nuclear fuels is their thermal properties, which are affected by the size distribution and morphology of thorium oxide particles. Thorium nitrate is the most common method for producing thorium oxide. Since no purification processes occur in the production of thorium oxide from oxalates, particle size and shape control are crucial. In this paper, the synthesis of thorium oxalate particles is carried out in a microreactor system to control the parameters of the precipitates. The main parameters that influence the efficiency, size distribution, and morphology of thorium oxalate are the concentration ratio of oxalic acid to thorium nitrate solution, as well as the flow rate ratio of these feed materials. Results show that at lower flow rate ratios of thorium nitrate to oxalic acid solution and higher concentration ratios of acid to thorium nitrate solution, a uniform particle size distribution and smaller particles are obtained, which are suitable for further calcination to prepare high-density and small grain size pellets.

Results in Engineering Experimental investigation of drag loss and plate separation behavior of wet clutches under external forces

Understanding the drag loss behavior of wet clutches is crucial for the development of low-loss clutch systems. For non-horizontal installation positions and non-stationary applications, external forces caused by the inclination or vehicle dynamics act on the plates. It has yet to be investigated how external forces influence the plate separation process and distribution and, subsequently, the drag loss behavior. Therefore, this study aimed to fundamentally investigate wet clutches' drag loss and plate separation behavior under the effect of external forces. The investigations were conducted in three steps. First, fundamental knowledge of the plate separation and drag loss behavior was gained. The effects of relevant design and operating parameters on the drag loss behavior were determined then. Separation springs were finally tested to avoid the influence of external forces. The drag loss and plate separation behavior were investigated on a drag torque test rig based on different clutch systems. The external forces were applied by inclining the test rig. The plate separation behavior was determined through image-based measurement of the plate movements. It was found that the plates separate under external forces and that the drag torque curve shows characteristics similar to wet clutches operated without external forces applied. The utilization of the set total clearance depends on the inclination angle. Hence, increasing the set total clearance does not generally imply lower drag losses, but increasing the inclination angle leads to higher drag losses. It was confirmed that the drag loss behavior is not influenced by external forces when using spacing elements. The findings of this study extend the existing body of literature and may support the development process of brake and clutch systems.

Utilization of fly ash composite from municipal solid waste incineration (MSWI) as an adsorbent to remove methylene blue from wastewater

Abstract Utilization of MSWI fly ash and corncob by combining fly ash and corncobs with a 1:10 ratio, activated with 75% KOH as an adsorbent to reduce methylene blue dye in textile wastewater. For the characterization testing of FACC, SEM-EDS, and pHpzc were used to determine the morphological conditions and pH value when FACC is in zero charged condition. Characterization results show that FACC has a rough surface and many pores with O, C, and K as dominant elements. pHpzc test shows that FACC will have a zero charge at pH 13.18. Experiments were conducted with batch method on the effect of adsorption operational parameters at contact time (0-120 min), FACC dosage (0.05-0.5 g/L), pollutant concentration (50-250 mg/L), and initial pH (2-10). Maximum removal efficiency was obtained at a contact time of 60 minutes, with a dosage of 0.5 g/L, pollutant concentration of 50 mg/L, and initial pH of 4 with a removal % of 98.37%. The Langmuir isotherm model described the adsorption mechanism with the maximum adsorption capacity reaching 344.828 mg/g. The adsorption rate used a pseudo-second-order kinetics model with a K2 value of 13.9 × 10−3 g/mg.min. FACC are good adsorbent alternatives for removing dyes in industrial wastewater.

Thermodynamic Efficiency Analysis of a Combined Power and Cooling (ORC-VCRC) System Using Cyclopentane (C5H10) as a Substitute for Conventional Hydrocarbons

The present study investigation aims to contribute to the field of energy engineering by exploring the performances of cyclopentane gas as promising working fluid in combined power and cooling (ORC–VCRC) system. The present research emphasizes the comparative computation of various thermodynamic performance characteristics of (ORC–VCRC) system activated by low temperature heat sources using cyclopentane gas as a substitute to the conventional hydrocarbons (butane, isobutene, propane and propylene) widely used in (ORC–VCRC) system. A computer code was developed using MATLAB software for the numerical simulation. The performance characteristics computed are the performance indicators (overall coefficient of performance (COPoval) and working fluid mass flow rate of per kW cooling capacity (MkW), expansion ratio in expander (EPR) and compression ratio in compressor (CMR). Furthermore, the effects of different operating parameters (e.g., boiler, condenser, and evaporator temperatures, isentropic efficiency of expander (ηexp), and isentropic efficiency of compressor (ηcomp)) on performance indicators are also examined for each working fluid. Results showed that under the same operating parameters, the use of cyclopentane gas as a working fluid in (ORC–VCRC) system exhibited a higher COPoval and lower MkW compared with conventional hydrocarbons. When boiler temperature reaches 90 °C, the COPoval of cyclopentane increase by 14 %, 19.8 %, 43.8 % and 59 % compared to those of butane, isobutene, propane and propylene, respectively. However, the MkW of cyclopentane reduced by 19.1 %, 29.2 %, 44.3 % and 53.7 % compared to same fluids, respectively. On another hand, the study revealed that the COPoval rises as the temperature of the boiler, evaporator, exp and comp rises. Conversely, when the condenser temperature rises, the COPoval value falls for all fluids. Overall, the study confirms that cyclopentane gas could be a promising working fluid in terms of performance indicators for (ORC–VCRC) system.

An efficient low-grade thermal energy dual-driven elastocaloric cooling system: Thermodynamic cycle analysis, economic and sustainability assessment

Elastocaloric cooling is regarded as the most promising emerging refrigeration technology, with heat driven elastocaloric cycles at the forefront of research. However, existing systems often have actuators with a mass of 4–20 times that of the refrigerant, resulting in bulky structures and low thermodynamic efficiency. Enhancing system compactness and efficiency has thus become a critical research challenge. This study proposes an innovative low-grade thermal energy dual-driven elastocaloric cooling system, achieving a 1:1 mass ratio (mActuator/mRefrigerant) between the actuator and refrigerant, significantly improving system compactness and coefficient of performance while effectively reducing costs. A three-dimensional numerical and geometric model was developed to analyze the thermodynamic cycle, examining the effects of material, operational, and geometric parameters on cooling performance, and a “category-wise optimization” strategy was employed to determine optimal parameter combinations. The cost and environmental impacts of the new system were evaluated and compared with vapor-compression air conditioning. Results show that the difference in transformation temperatures between austenite and martensite phases significantly impacts cooling performance. Optimal flow rates and cycling frequencies are essential to avoid performance loss. Considering the coefficient of performance and heat transfer, a 1:1 mass ratio is optimal for geometric parameters. The system achieves a maximum coefficient of performance of 0.158, exceeding the existing two schemes by more than 2 times and 7 times, with a maximum temperature rise of 13.1 K. The proposed system is economically feasible and environmentally friendly, providing valuable theoretical foundations and technical solutions for developing sustainable alternative refrigeration technologies.

Electro-osmotic flow-based microfluidic biosensor: effect of design and operating parameters

Electro-osmotic flow-based microfluidic biosensor: effect of design and operating parameters

Nanoparticle deagglomeration driven by a high shear mixer and intensification of low-speed stirring in a viscous system

High shear mixers (HSMs), with their unique advantages of high shear forces and a wide operational range, are commonly used in nanoparticle deagglomeration. This study explores a novel approach to intensifying nanoparticle deagglomeration in a 100 mPa‧s viscous system using HSMs combined with low-speed stirring. The effects of main operating and structural parameters were experimentally investigated. The results show that the teethed HSM outperforms the blade-screen HSM, achieving a smaller attainable size (114 nm vs. 210 nm) and a higher fine particle generation fraction (46.08% vs. 18.77%). Increasing HSM size directly affects the energy input (from 6.478 MJ/kg to 31.879 MJ/kg), which influences the deagglomeration mechanism and kinetics but does not affect the smallest attainable size (117 nm). Higher solid contents improve energy efficiency, while low-speed stirring, though not altering the deagglomeration mechanism, enhances its kinetics. The process intensification factor (S) and energy efficiency factor (εm) were defined to evaluate the intensification of low-speed stirring. Increasing the impeller speed enhances this effect. The PBT impeller with a diameter ratio of 0.35 is identified as the ideal structure in this study, improving deagglomeration performance by 8.26% while reducing energy consumption by 8.3%. These results provide guidance for optimizing processes and improving deagglomeration performance through the combination of low-speed stirring in viscous systems for process industries.

A multi-objective analysis for enhanced energy and exergy performances of an integrated compressed air energy storage system using the meta-heuristic whale optimization algorithm

This study investigates the optimization of energy and exergy efficiencies in a compressed air energy storage integrated energy system using the meta-heuristic whale optimization algorithm. The analysis focuses on the effects of key operating parameters, including current density, utilization factor, and temperature, on the system's performance. The whale optimization algorithm identifies seven multi-objective optimum points, with processing conditions ranging from a current density of 3000 A/m2 to 5237 A/m2, utilization factors between 0.740 and 0.747, and temperatures from 700 °C to 900 °C. Desirability analysis reveals that some points, with a desirability value of 1, are the most optimal. Among these, one point characterized by a utilization factor of 0.747, a current density of 3000 A/m2, and a temperature of 700 °C, is identified as the optimal point. Under these conditions, the system achieves an energy efficiency of 66.63 % and an exergy efficiency of 34.85 %. The study highlights the significant potential of the meta-heuristic whale optimization algorithm in navigating complex search spaces to identify optimal processing conditions. The results underscore the importance of balancing electrical and thermal efficiencies to achieve overall system optimization using meta-heuristic optimization algorithms.

Neutron Depolarization Under Electrochemical Polarization: Investigating Phase Change Reactions in All-Iron Redox Flow Batteries

Large-scale and low-cost energy storage systems are necessary to integrate renewable energy technologies into the electrical grid. Among the options, all-iron redox flow batteries (AIRFBs) are a promising candidate as they can strike a good balance between flexibility and modularity [1]. Additionally, they employ sustainable and abundant raw materials in both half cells, thus decreasing their capital costs and their need for maintenance, which contribute to lower levelized cost of storage [2]. However, AIRFBs still suffer from certain operational challenges, such as the unoptimized and segregated electrodeposition of the active species and the competitive hydrogen evolution reaction [3]. Conventional characterization techniques cannot accurately determine the spatial distribution of both reactions within the electrochemical cell, and thus the operational losses they generate still remain unclear.In recent years, several groups have explored non-invasive operando characterization of RFBs by use of nuclear magnetic resonance[4] or fluorescence microscopy[5], among others. Recently, our group developed a neutron radiography-based method to visualize concentrations in solution of redox or charge carrier species, enabling visualization of local concentration effects [6]. Nevertheless, this approach relies solely on species in solution providing high attenuation, such as H-, B-, or Li- containing electrolytes. Therefore, this attenuation mechanism severely restricts the types of species or phases that can be probed, and the regions of interest where the metal electroplating occurs would remain difficult to quantify with conventional neutron imaging [7].In this work, we expand the workspace of neutron radiography in electrochemical cells to systems employing substances of lower neutron cross section by combining the use of in-plane transmission and polarized neutron imaging. With this dual characterization approach, we are able to visualize for the first time the distribution of iron plated species and hydrogen evolution during electrochemical operation in an all-iron redox flow battery. First, we validate the proposed methodology by performing ex-situ measurements of the depolarization response caused by the magnetic momentum of the various iron-containing species that could form during the charging process of the AIRFB system. We find that only purely ferromagnetic substances (e.g. microscale alpha-iron particles) produce a strong and depolarizing response, with a linear dependence between the depolarization coefficient and the weight fraction of the magnetic phase, thus enabling the detection of subtle changes in plated iron content. On the contrary, weak ferri- or paramagnetic compounds, such as Fe2O3, Fe3O4 or FeOOH, do not cause interference in the measured signal.Subsequently, we run an all-iron redox flow battery at the BOA neutron beamline and performed simultaneous neutron imaging under two modes. By means of the polarization contrast neutron imaging, we tracked the electrodeposition of iron during charge and its removal during discharge within the negative electrode, correlating operating conditions with the distribution of the plated species in the porous carbon electrodes. Simultaneously, the neutron transmission mode and subtractive imaging enabled visualization of hydrogen gas evolution and its dynamics within the cell. These results provide insights into the break-in behavior of phase change reactions and the distribution of the simultaneous reactive fronts of the multiphase, hybrid type of flow cell. In turn, we were able to obtain fundamental understanding of the effects of operational and design parameters, such as electrolyte composition, flow field design and flow distribution geometry, and their impact on the mass transfer characteristics and efficiency of all-iron flow batteries. Acknowledgements IGG gratefully acknowledges financial support by “la Caixa Foundation” (ID 100010434) under the fellowship number LCF/BQ/EU20/11810076. AFC gratefully acknowledges funding by the European Union (ERC, FAIR-RFB, ERC-2021-STG 101042844). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them. The results of this project are based on experiments performed at the Swiss Spallation Neutron Source, SINQ, Paul Scherrer Institute (Switzerland), with proposal number 20222727 References [1] Dunn, B., Kamath, H., & Tarascon, J. M. (2011). Science, 334(6058), 928-935.[2] Li, B. & Liu, J. (2017). National Science Review, 4(1), 91-105.[3] Zhang, H., & Sun, C. (2021). Journal of Power Sources, 493, 229445.[4] Zhao, A. et al. (2020) Nature¸ 579, 224[5] Wong, A.A., Rubinstein, S.M. & Aziz, M.J. (2021) Cell Reports Physical Science 2(4), 100388[6] Jacquemond, R.R. et al. (2023) ChemRXiv , ID 10.26434/chemrxiv-2023-8xjv5[7] Kardjilov, N. et al. (2011) Materials. Today, 14(6) 248-256