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Power characteristics are important indicators of fuel cell performance. In the actual operation of fuel cells, changes in operating conditions lead to variations in their power characteristics. Therefore, it is imperative to explore the impact of operating conditions on power characteristics. This paper analyzes the factors influencing fuel cell power and uses sensitivity analysis to investigate how different factors affect fuel cell performance. The operating parameters are optimized using a Bayesian-optimized Gaussian process regression model. The research results indicate that temperature has the greatest impact on fuel cell power, followed by stoichiometry and backpressure. The Bayesian-optimized Gaussian process regression model performs the best, reducing its RSME from 0.1 to 0.0556. Residual analysis and regression characteristic analysis verify the optimized model's improved fitting and regression characteristics. Based on the Bayesian–Gaussian process regression model, the optimized operating parameters are obtained for maximum power: a temperature of 80 °C, stoichiometry of 4, and backpressure of 1.7 bar. This paper provides theoretical support for improving fuel cell performance. [ABSTRACT FROM AUTHOR]

A computational model was developed to investigate the significance of system design and operating conditions on the rejection of neutral, low‐MW organics by reverse osmosis for potable reuse. The model demonstrated that the decrease in local rejection as net driving pressure decreases is substantially greater for moderately rejected compounds than for highly rejected compounds. At recovery values less than 70%, the local permeate concentration can exceed the pressure vessel feed concentration for moderately rejected compounds. System‐level rejection of moderately rejected compounds is likewise substantially more sensitive to operating conditions than highly rejected compounds. The findings highlight a drawback of relying on rejection results from bench‐scale testing that operates at low recovery, which invariably has higher rejection than full‐scale systems operating at similar pressure. The analysis demonstrates a trade‐off in which the low‐pressure, high‐recovery operation desired for potable reuse systems can be detrimental to the removal of low‐MW neutral organics. The removal of low‐MW neutral organics can be improved if organics rejection is explicitly evaluated during the design process. [ABSTRACT FROM AUTHOR]

A one-dimensional computational model has been developed that can be used to identify operating conditions for the cathode side of a proton exchange membrane fuel cell such that both the inlet and outlet relative humidity is equal to 100%. By balancing the calculated pressure drop along the cathode side flow channel with the change in molar composition, inlet conditions for the cathode side can be identified with the goal of avoiding channel flooding. The channel length, height, width and the land-to-channel width ratio are input parameters for the model so that it might be used to dimension the cathode flow field. The model can be used to calculate the limiting current density, and we are presenting unprecedented high values as a result of the high pressure drop along the flow channels. Such high current densities can ultimately result in a fuel cell power density beyond the typical value of 1.0–2.0 W/cm2 for automotive fuel cells. [ABSTRACT FROM AUTHOR]

The convective hot-air drying technology can cause physicochemical, nutritional, and organoleptic losses in the mango (Mangifera indica). The present Systematic Review was carried out with the objective of comparing mango dehydration technologies to identify the effects on the physicochemical, nutritional, and organoleptic properties of the fruit. Through a review of published scientific and conference papers in the Scopus database, adjusted to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) methodology, a total of 134 documents dated between 2000 and December 6 of 2022 were obtained; 76 of these documents were finally included in the bibliographic and theoretical analysis. Selection parameters emphasizing the relationship between the articles and the research topic, evidenced by including at least one of three dehydration technologies and the fruit of interest with an experimental or theoretical approach to the dehydration subject; review articles and surveys were excluded. Correlation graphs of bibliographic variables were made using the data mining software VantagePoint (version 15.1), which was graphically restructured in Microsoft Excel with the support of statistical analysis. Of the resulting articles, it was found that the countries with authors who participated most in scientific production like India, Brazil, Colombia, the United States, and Thailand, were those related to mango production or importation. Furthermore, the freeze-drying technology allows operating at lower temperatures than convective hot-air drying, contributing to the preservation of ascorbic acid, among other compounds. The refractance window has the shortest operation time to obtain moisture values between 10 and 20%. The dehydrated samples using the refractance window are smooth, homogeneous, non-porous, and comparable to the color obtained with freeze-drying, which is acceptable for industrial applications. [ABSTRACT FROM AUTHOR]

Chemical recycling of Polyethylene Terephthalate (PET) has gotten great attention today. Aminolysis, one of the chemical recycling methods, is the degradation of polyesters using primary amines that attack its functional group. It is not much explored as a commercial recycling technique among the chemical recycling methods. This review aims to explain the aminolysis method of PET degradation in terms of reaction operating conditions such as PET to solvent ratio, temperature, degradation time, and catalyst dosage. The primary product of aminolysis of PET is also discussed and their most common application in the preparation of secondary products is presented. Thus, PET-derived primary products can be used to synthesize polymers such as polyurethane and develop enhanced products like paints and coatings. Additionally, nonconventional procedures of PET aminolysis techniques: such as microwave radiation, ultrasound, UV radiation, and sunlight were assessed by comparison. [ABSTRACT FROM AUTHOR]

Proton exchange membrane electrolytic cell (PEMEC) is considered a promising way to produce green hydrogen due to its advantages of high current density, rapid start and stop, and high purity of hydrogen production. However, the existing macroscopic modeling of the PEMEC lacks the consideration of MPLs and the comprehensive study of heat and mass transport. In this paper, a one-dimensional two-phase non-isothermal PEMEC model with microporous layers is established, which accounts for a complete description of mass, charge, and heat transport. The polarization curves of numerical simulation are in good agreement with the experimental data. Then, the model is used to parametric analyze the effects of operating conditions and component parameters on heat and mass transfer, voltage loss, and efficiency for the PEMEC. The results show that operating pressure has a significant influence on the electrolytic performance. Voltage loss reduced of 30.75 mV and maximum temperature of 1.74 K occur when operating pressure increases from 1atm to 3atm, respectively. The characteristics of PTL and MPL mainly affect mass transport, and when PTL thickness and MPL thickness reduce by 100 μm and 20 μm respectively, the oxygen molar fraction reduces by 4.96% and 0.94%, respectively. The application of higher porosity, permeability, and thinner PTL with a thinner microporous layer (MPL) can effectually improve the operation efficiency of PEMEC. The model results presented in this study provide a theoretical basis for the optimization and design of the PEMEC. • A 1D two-phase, non-isothermal macroscopic model of a PEMEC with MPLs is presented. • The model is validated against experimental data from literature. • A parametric analysis of operating condition and component parameter are performed. • Operating condition of High voltage, high temperature and high operating pressure are desirable. • Requiring thin PTL with high porosity and low permeability is coated with thin MPL. [ABSTRACT FROM AUTHOR]

The first focus of this study is to investigate the design and behavior of locally built solar dryer during processing henna leaves. This was performed through the determination of the most important parameters that effect drying process. Appropriately, it was found that solar radiation has a direct effect on the collector outlet air temperature and consequently the product moisture content. Accordingly, high radiations lead having high air temperature at the drying chamber and consequently, the moisture content will decrease rapidly. Similarly, lower radiations will still lead to decrease of the moisture content, however, the drying rate will be less important than at high radiations. On the other hand, air velocity has an inverse dissipative effect of the energy and its increase leads to the decrease of the outlet temperature of the solar collector. Indeed, the highest outlet temperature from the solar collector was around 32 °C at an air velocity of 2 m/s. At 5.5 m/s, this temperature dropped to around 27 °C. The second objective of this study is to present the effect of different drying methods (i.e. forced convective solar drying and open sun drying) of Lawsonia inermis on the content of secondary metabolites (phenolic and flavonoid compounds) and compare the results with fresh henna samples. The yield of phenolic compounds was determined, and the dry crude extracts were found to be richer than the fresh sample in all of the drying modes used. The best yields are obtained with convective solar dryer and open sun drying samples (28.6 and 13.93%), respectively. The total phenolic and flavonoid contents of convective solar dryer product were 25 and 10% higher than open sun dried samples. Antioxidant tests (DPPH, ABTS, and ferric reducing power) revealed the scavenging and reducing abilities of the extract dried with the solar dryer. The values of antioxidant capacities measured by the three different methods were all consistent, appropriate, and highly correlative for assessing total antioxidant capacities. The solar dryer allows the preservation or even the increase of the antioxidant activity of the tested extracts. [ABSTRACT FROM AUTHOR]

Operation at high current density of polymer electrolyte membrane electrolysis cell (PEMEC) can reduce its electrode area and capital expense. The high current density operation is limited by the limiting current density (LCD), where electrolysis voltage abruptly increases. Effects of operating temperature and pressure on the LCD were evaluated in a lab-scale PEMEC within a range from 70 to 90 °C and from 0.1 to 0.3 MPa. Also, a theoretical model was developed to predict the LCD, and to clarify what determines LCD and how the operating conditions influence the LCD. The theoretical analysis suggests that when current density is close to the LCD, water mass transport at anode reaches a limitation, which indicates that water saturation reaches almost zero at anodic catalyst layer. The analysis also finds that lower operating temperature and higher operating pressure can reduce oxygen gas saturation and raise the water saturation in porous transport layer at anode, and finally enlarge the LCD. • Limiting current density (LCD) is decided by mass transport limitation. • Oxygen gas saturation near catalyst layer is close to 1 at LCD. • Bubble overvoltage abruptly rises at LCD. • Lower temperature and higher pressure enlarge LCD. [ABSTRACT FROM AUTHOR]

Due to high greenhouse gas emissions, countries worldwide are stepping up their emission reduction efforts, and the global demand for new, carbon-free fuels is growing. Ammonia (NH3) fuels are popular due to their high production volume, high energy efficiency, ease of storage and transportation, and increased application in power equipment. However, their physical characteristics (e.g., unstable combustion, slow flame speed, and difficult ignition) limit their use in power equipment. Based on the structural properties of the power equipment, NH3 fuel application and emissions characteristics were analyzed in detail. Combustion of NH3 fuels and reduction measures for NOx emissions (spark plug ignition, compression ignition, and gas turbines) were analyzed from various aspects of operating conditions (e.g., mixed fuel, fuel-to-exhaust ratio, and equivalence ratio), structure and strategy (e.g., number of spark plugs, compression ratio (CR), fuel injection, and ignition mode), and auxiliary combustion techniques (e.g., preheating, humidification, exhaust gas recirculation, and secondary air supply). The performance of various NH3 fuel cell (FC) types was analyzed, with a focus on the maximum power achievable for different electrolyte systems. Additionally, the application and NOx emissions of indirect NH3 FCs were evaluated under flame and catalytic combustion conditions. The system efficiency of providing heat sources by burning pure NH3, anode tail gas, and NH3 decomposition gas was also compared. Based on a comprehensive literature review, the key factors influencing the performance and emissions of NH3-powered equipment were identified. The challenges and limitations of NH3-powered equipment were summarized, and potential strategies for improving efficiency and reducing emissions were proposed. These findings provide valuable insights for the future development and application of NH3 FCs. [ABSTRACT FROM AUTHOR]

High-voltage heat release from batteries can cause safety issues for electric vehicles. Relevant scientific research work is carried out in the laboratory. The battery safety of laboratory experiments should not be underestimated. In order to evaluate the safety performance of batteries in the laboratory testing of driving conditions of electric vehicles, this paper simulated and compared the discharge characteristics of two common batteries (lithium iron phosphate (LFP) battery and nickel–cobalt–manganese (NCM) ternary lithium battery) in three different operating conditions. The operating conditions are the NEDC (New European Driving Cycle), WLTP (World Light Vehicle Test Procedure) and CLTC-P (China light vehicle test cycle) for normal driving of electric vehicles. LFP batteries have a higher maximum voltage and lower minimum voltage under the same initial voltage conditions, with a maximum voltage difference variation of 11 V. The maximum current of WLTP is significantly higher than NEDC and CLTC-P operating conditions (>20 A). Low current discharge conditions should be emulated in teaching simulation and experiments for safety reasons. The simulation data showed that the LFP battery had good performance in maintaining the voltage plateau and discharge voltage stability, while the NCM battery had excellent energy density and long-term endurance. [ABSTRACT FROM AUTHOR]

Transient vehicle dynamics are deeply affected by the spatial distribution of tire temperature, heat generation, and heat dissipation capacity. However, the tire testing process involves numerous parameters, adding the complexity to monitoring the tire's thermal properties variation. To address this issue, this paper proposes a data-driven framework that combines the well-known Magic Formula with scaling factors and a long- and short-term memory (LSTM) neural network. The framework forecasts tire thermal properties and functionality under given conditions by learning from time-series data on tire operating conditions and mechanical characteristics. It predicts future spatially varying thermal properties of the tire, including temperatures, heat generation, and heat dissipation. This is achieved with a high degree of forecasting ability quantified by train size/test size ratios equaling 22 and 38% with an impressive Relative Root Mean Square Error (RRMSE) around 1−2%. Here, this framework is applied to quantify the impacts of various operating conditions, including vertical load, slip angle, and vehicle speed, on heat transfer for three crucial radial positions on the tire. Our results show that the vertical load is the primary influencing parameter among all operating conditions. The knowledge about transient tire dynamics will be advantageous to their performance optimization. [ABSTRACT FROM AUTHOR]

The reliability of a car engine is ensured by the combination of oil properties that are laid in the oil production process. The properties of engine oil change with the mileage of the car compared to the initial state. When the rejection parameters of the oil reach the limit level, then it is necessary to replace the old oil with a new one. The rate of change intensity in the properties of particular oil depends on both the make of the vehicle and the operating its conditions. In difficult conditions of operation of the car, it is necessary to reduce the run period of between oil changes. But if the car is operated in light or gentle conditions, then the normative oil change may not realize its full potential. In this case, extending the oil change intervals beyond the norm leads to an increase in the efficiency of its use, which reduces the overall operating costs. It will be optimal when the service life of the oil will be determined by the actual state of the basic properties. The paper presents the results of experimental studies on changes in the concentration and rate of iron entry into motor oil. In addition, other indicators of oil in samples were determined: the viscosity, the flash point in an open crucible, the dielectric constant, the acidity and alkali numbers. The study involved motor oils of the same group, but from different manufacturers, for various brands of trucks and cars at different stages of the life cycle. The energy loading on the engine can be estimated by fuel consumption, which depends on the operating speed or operating conditions of the vehicle. An analysis of the results experiment was carried out, which established a relationship between the concentration of iron in oil and fuel consumption or car mileage. In conclusion, recommendations are given on the values of indicators at which further operation of oils is not recommended. [ABSTRACT FROM AUTHOR]

In order to solve the safe construction and high-quality performance of super-large caisson in long-period wave areas on the west coast of Africa, the wave monitoring data for 30 years in the construction area and the construction difficulties of the supporting project were investigated and analyzed. Based on the measured data of long-period waves in the sea area, the joint distribution and probability statistics of significant wave height and spectral peak period, as well as the conditions of continuous construction operation, were analyzed. The probability distribution law of significant wave height and spectral peak period and the most favorable working time of different projects were obtained, and the guiding opinions for construction operations in the sea area were given, which provides a basis for the research on the construction deployment of super large caisson in long-period wave areas. [ABSTRACT FROM AUTHOR]

A monopile is the most popular foundation type for wind turbines. However, the dynamic performance of monopile-supported wind turbines under different operating and ground conditions is not fully understood. In this study, an integrated monopile-supported wind turbine model in a wind tunnel was employed to jointly simulate the operating and ground conditions. A series of wind tunnel tests were designed and performed to investigate the dynamic performance of monopile-supported wind turbines. These tests included seven operating conditions (seven wind speeds and corresponding rotor speeds) and four ground conditions (one fixed ground condition and three deformable ground conditions with different soil relative densities). According to the test results, the structural responses and dynamic characteristics were analyzed and discussed. This shows that the assumption of fixed-base support significantly overestimates the natural frequency but underestimates the global damping ratio. With the increase in soil relative density, the natural frequency slightly increases, while the damping ratio decreases more significantly. With the increase in the wind speed and rotor speed, the increase in global damping is larger on softer ground. A regression analysis was performed to estimate the global damping ratio under different operating and ground conditions. [ABSTRACT FROM AUTHOR]

In this paper, a tribo‐dynamic model of a helical gear is established. For the lubrication sub‐model, a finite line thermal elastohydrodynamic lubrication model of helical gear is adopted. The lateral vibration, axial vibration of gear and torsional vibration of the gear shaft are considered in the dynamic sub‐model. Results show that the tribological parameters of helical gear under the tribo‐dynamic model deviate significantly from that of the quasi‐static model, especially in the engaging‐in region of tooth pair. The friction excitation mainly affects the vibration along the off‐line‐of‐action direction of the gears. The influence of operating conditions on the tribological and dynamic properties of a helical gear pair is significant, especially in the case related to the characteristic frequency of gears. [ABSTRACT FROM AUTHOR]

Heat exchanger optimization is a very efficient thermal design inquiry. The goal of the research is to determine an optimal channel flow velocity as well as an optimal total plate number based on overall information on the effectiveness of employing chilled water to cool soybean milk. Heat transfer coefficient, Prandtl number, Reynolds number and pressure drop measurements were applied for milk and water. The rheological properties of soybean milk have been investigated at various temperatures (5, 10, 30, 50, 70 and 90 °C). The operational circumstances of PHE in soybean procedures were investigated at different numbers of plates, flow rates and flow velocities. Based on the present study, total substances showed non-Newtonian pseudoplastic conduct in any respect at any temperature and the power law model has a decent correlation. The cost estimation of the plate heat exchanger was observed at the lowest flow velocity of (2.25) m/s and number of plates is 17. [ABSTRACT FROM AUTHOR]

Due to their low cost, lightweight, antifouling and anticorrosion properties, polymer heat exchangers (PHXs) are replacing metal heat exchangers in a variety of applications. Nowadays, 3D printing technology is gaining increasing attention to fabricate these PHXs. This study employs Fused Deposition Modeling (FDM), a popular 3D printing technique, to construct PHXs from ABS material (i.e., Acrylonitrile Butadiene Styrene) and investigates some of the important parameter effects on their heat transfer performance under varied operating conditions. Experiments were performed for the shell side flow rates varying from 0.6 to 3 L/min and tube side flow rates varying from 1.2 to 3.6 L/min. The overall heat transfer coefficient (U) ranged from 66 to 121 W/m2 K in these printed PHXs, thereby showing the effect of printing and operating conditions. The results showed that the printing temperature (PT) and tube wall thickness (WT) had a significant influence on the thermal performance of PHXs while the printing speed (PS) demonstrated a trivial effect. Apart from enhancing the thermal performance, higher printing temperature also resulted in lowering the dimensional variations. The roughness analysis of the tubes revealed that the PHXs with smooth surfaces interestingly had better heat transfer performance than tubes with rougher surfaces. Further, such smooth surfaces were realized with a high printing temperature. These findings conclude that higher roughness does not necessarily improve the thermal performance of layered PHXs, contrary to continuous structure HXs. Also, high printing temperature, small wall thickness, and low printing speed are conducive conditions to produce printed PHXs with greater thermal performance, and reduced roughness and dimensional variations. This study can act as a guideline for printing precise and high-performance PHXs. [ABSTRACT FROM AUTHOR]

Operating conditions and selectivity of a new perovskite nanocatalyst were studied in Fischer‐Tropsch synthesis using a fixed‐bed microreactor. Selectivity equations were obtained using the experimental data collected from a hydrogenation process in a fixed‐bed microreactor. The operating conditions were obtained by defining the design‐of‐experiment scope based on response surface methodology, on 3 levels and in 15 tests. The optimum selectivity for alkenes relative to alkanes was obtained at 349.7 °C, 3.2 bar, and a H2/CO volumetric ratio of 1. Also, the optimum selectivity for alkenes relative to the overall selectivity for other products was attained at 250 °C, 2.3 bar, and a feed volumetric ratio of 2. [ABSTRACT FROM AUTHOR]

In the vicinity of the top dead center of a diesel engine, the piston rings operate in a low-speed, high-load, and high-temperature environment, which is detrimental to the formation of an effective lubrication oil film. Consequently, it presents significant challenges for predicting the tribological characteristics of the piston ring-cylinder liner friction (PRCL) assembly. This study explores the micro-friction behavior of PRCL assemblies near the top dead center in engines using the molecular dynamics approach. The tribological characteristics of the PRCL, especially the microscopic wear mechanisms, were analyzed under various operating conditions such as ring sliding speed, ring back load, operating temperature, and lubricant supply amount. The liner surface morphology, liner wear, and lubricant film distribution were used to evaluate the tribological characteristics. It was determined that the lubricant supply amount has the most significant impact on the micro-friction behavior of the PRCL assembly. [ABSTRACT FROM AUTHOR]

A range criterion of discounted costs is proposed, which takes into account all costs for a speed-controlled asynchronous electric drive, including its price, costs of losses and maintenance, and amortization charges. It is also possible to take into account the cost and energy performance of matching transformers and gearboxes. Costs for reactive power compensation of both the first and second kind (due to the presence of harmonic components at the drive input) are taken into account. The latter requires determining the total harmonic distortion (THD) of the currents consumed by the drive. In the case of autonomous power systems, it is also necessary to determine the drive's supplying voltage non-linear distortion coefficients. Representing the discounted costs as the sum of initial capital investments and annual costs made possible taking into account the presence of inflationary processes. The control characteristics of the active power consumed by the drive, efficiency, power factor, and phase shift factor are constructed, which are dependencies on the rotation frequency in a certain control range at a specific load. It is proposed to calculate the drive's discounted costs criterion, depending on the operating mode of the load. According to the mode, the criterion is calculated as an average range in a certain range of speed control or is determined taking into account a given tachogram of speed changes. For the controlled asynchronous drive under consideration, the discounted costs are 4148 c.u. in the first case and 5139.3 c.u. in the second case. If inflationary processes are taken into account, the first case is 4219.4 c.u. and the second case is 5227.7 c.u., respectively. [ABSTRACT FROM AUTHOR]

Decarbonization of the transport sector could be achieved through fuel cell technology. The candidature of this technology is motivated by its high current density and lack of emissions. However, its widespread deployment is restrained by durability and reliability constraints. During normal operation, the fuel cell system supplies stable power to the load. Contrarily, when it is operated under faulty conditions, the system's output power deteriorates, leading to low durability. It is therefore of paramount importance to ensure that the system is operated in a non-faulty condition. In this paper, we provide a critical review of the analytical-redundancy-based fault diagnosis methods for proton exchange membrane fuel cells (PEMFCs). An in-depth analysis of the various methods has been presented in terms of accuracy, complexity, implementability, and robustness to aging and dynamic operating conditions. [ABSTRACT FROM AUTHOR]

The operation data of nuclear power plants record the status of nuclear power plants. The data processing and analysis of nuclear power plants can realize the operation status inspection and monitoring of nuclear power plants, and the division of working conditions is the basis for the operation status monitoring of nuclear power plants. The Gaussian mixture model based on density peak clustering was proposed to divide the operating conditions of nuclear power plants. Firstly, the principal component analysis(PCA) algorithm was used to reduce the dimensionality of the data, and then the decision graph in the density peak clustering algorithm was used to determine the number of working conditions, and finally the Gaussian mixture model is used to complete the classification of working conditions. Experiments were conducted based on real nuclear power plant operation data. The experimental results show that the proposed method can reasonably and effectively classify the operating conditions of nuclear power plants. The classification accuracy of the three types of operating conditions reaches 99. 29%, 100% and 97. 57% respectively, and the error rate is only 1. 25%. [ABSTRACT FROM AUTHOR]

HVDC transmission systems are becoming more prevalent because of the advantages they offer. They are more efficient and environmentally friendly and are becoming preferred in distributed power generation. The reliable operation of HVDC transmission lines requires distributed, online monitoring, which is not as well-developed as those in an HVAC system. The advancement of HVDC systems will require online monitoring that provides information on the operating and environmental conditions, mechanical stress on the conductors and the structure, vegetation clearance, and security of the system. This perspective paper provides a thorough overview of the state-of-the-art technologies that are applicable to the monitoring of HVDC transmission lines. The challenges and future direction in the development of sensors for HVDC applications are highlighted. One of the key challenges unique to HVDC transmission lines is energy harvesting from the transmission line conductors to provide power for the monitoring equipment. This paper reviews the potential technologies for energy harvesting from HVAC transmission lines and their suitability for employment in HVDC transmission lines. [ABSTRACT FROM AUTHOR]

As the heavy metal ion in aqueous solutions, Pb2+ has certain harm to the surrounding natural and ecological environment. To eliminate the pollution of Pb2+ in aqueous solution, Na-type zeolite was prepared from the coal gasification slag by alkaline activation technology, and then the hydrodynamic of fluidized bed with Na-type zeolite granules was studied to achieve fluidization stability. Finally, the adsorption process and mechanism of Pb2+ in aqueous solutions using Na-type zeolite were studied by multiple adsorption experiments in stable fluidized bed. The results showed that: The removal process of Pb2+ using Na-type zeolite is a single-layer adsorption dominated by chemical adsorption, companying with surface electrostatic interaction and ionic exchange processes in the interlayer. Fluidized adsorption process of Pb2+ by Na-type zeolite is mainly affected by rising-water velocity, original concentration of Pb2+, and bed material quantity in fluidized bed. The order of influence significance was as below: Original concentration (c o) > Bed material quantity (m o) > Rising-water velocity (v t). Under optimal opera t ing conditions (c o =200 mg/L, v t =0.053 m/s, m o =72 g), t he fluidized bed have higher adsorption saturation (q s =0.649 g/g) than that of fixed bed (q s =0.501 g/g), promoting the adsorption process of Pb2+ by Na-type zeolite. This research provided a new method for the efficient removal of Pb2+ from aqueous solution. [Display omitted] [ABSTRACT FROM AUTHOR]

The aim of this research is to develop continuous reactor network models to determine the reactor configuration and corresponding optimal operating conditions of a polyolefin elastomers polymerization process. To achieve this objective, a modified vapor-liquid equilibrium model is integrated with both the continuous stirred tank reactor (CSTR) model and the plug flow reactor (PFR) model to accurately predict the vaporization rates of liquid. The multi-objective problem is formulated to maximize the monomer conversion and minimize the total annualized cost simultaneously. To solve the multi-objective problem, the genetic algorithm is utilized to identify the optimal operating conditions. Furthermore, the impact of the reactor combination mode is analyzed by varying the number and sequence of CSTR or PFR. The research findings reveal that a multi-phase CSTR without circulating stream followed by a PFR is the optimal reactor configuration. The proposed configuration can enhance reactor productivity and reduce the total annualized cost simultaneously while meeting the desired polymer properties. [Display omitted] • Optimization for a polyolefin elastomers polymerization process is performed. • Modified vapor-liquid equilibrium model is adopted in reactor simulation. • The genetic algorithm is applied in solving multi-objective optimization problem. • Reactor configuration and corresponding optimal operating conditions are obtained. [ABSTRACT FROM AUTHOR]

This paper investigates the importance of standardising and maintaining the transparency of advanced driver-assistance systems (ADAS) functions nomenclature, designs, and operations in all categories up until fully autonomous vehicles. The aim of this paper is to reveal the discrepancies in ADAS functions across automakers and discuss the underlying issues and potential solutions. In this pilot study, user manuals of various brands are reviewed systematically and critical analyses of common ADAS functions are conducted. The result shows that terminologies used to describe ADAS functions vary widely across manufacturers and sometimes do not reflect their fundamental functions intuitively. Operational conditions and control procedures also vary across the selected models under this study. Due to this lack of consensus across the industry, drivers are not aware or well informed about ADAS functions in their vehicles, leading to a very low utilization rate and may lead to misuse of those functions. This paper provides insightful suggestions for the transport industry, Artificial Intelligence (AI) experts, and regulators to design frameworks and guidelines in governing the naming convention, operating conditions, control procedures, and information disclosure of ADAS. Such guidelines can be the foundations for regulating future AI-based self-driving functions. [ABSTRACT FROM AUTHOR]

A comprehensive algorithm for calculating the energy yield (EY) is used as the most important figure‐of‐merit in determining the capabilities of PV devices in realistic operation. The model is based on advanced optical modeling and extensive opto‐thermo‐electrical characterization. It takes the realistic environmental and device installation data fully into account, as well as the complete set of device specifications including all relevant temperature‐induced variations. A detailed analysis and optimization of two‐terminal perovskite‐silicon tandem devices are done in terms of long‐term electrical energy production at different geographical locations from distinct Köppen–Geiger–Photovoltaic climate zones (KGPV). It is shown that the optimal perovskite bandgap (EG,PK) in a tandem device operating under realistic conditions is in all cases higher than the one optimized under STC, yet does not differ significantly from location to location, which is beneficial from the manufacturing point of view. The optimal EG,PK is influenced primarily by the spectral distribution of incident irradiance, and not so much by the operating temperature conditions. Moreover, a clear linear dependency between the optimal EG,PK and the weighted average photon energy of the incident irradiance is demonstrated, which presents an important rule for rapid tandem design. [ABSTRACT FROM AUTHOR]

Heat pump electricity costs grow with a power relationship as the evaporator temperature in the cycle decreases. The thermo-economic study of a solar thermal-assisted heat pump and storage system determines the minimum cost of the coupled system for an evaporator temperature. Through two case studies, one for the dairy industry and the other for 2G bioethanol production, the coupled system was evaluated for different temperatures in the evaporator, from 30 to 90 °C, and the minimum cost of the coupled system was determined. For the dairy industry, the lowest levelized total cost of a heat pump (LCOE) at 50 °C is 0.0799 USD/kWh. The evaluation carried out allowed us to determine the best operating conditions of the heat pump: 50 °C in the evaporator, COP = 4.2, and the work of the compressor of 211.3 kW. In the case of 2G anhydrous bioethanol production, the lowest levelized energy cost is 0.0409 USD/kWh for an evaporator temperature of 30 °C and a payback of 1.8 years. The study carried out makes it possible to guarantee the supply of the heat load at the operating temperature of the process and determines the impact of environmental conditions on the cost of the heat pump assisted with solar thermal energy. [ABSTRACT FROM AUTHOR]

Using renewable energy sources, the electrochemical CO2 reduction (ECR) into industrially important feedstock is a promising technology to neutralize the carbon cycle and generate energy-dense fuels. Herein, the ECR modeling in a flow cell to produce formate using Sn electrode is presented. We show the effect of different factors such as pressure, velocity, cell potential on the faradaic efficiency and current density of several products and pH around the cathode. The results show that high pressure is required to achieve high current density to maintain a constant faradaic efficiency at a constant velocity. For 2.7 V cell potential, the formate faradaic efficiency increases by 18% when the velocity is increased by an order of magnitude and this variation is not explicit at high-pressure values. The great influence on the formate current density can be observed at a constant cell potential when the pressure is increased, provided that the reduction process limits the mass transfer. At atmospheric pressure and 3.1 V cell potential, enhancing the velocity improves the cathode usage to perform CO2 reduction because decreased concentration boundary layers are observed at high velocity, which improves the CO2 flux for the cathode and also provides the CO2 across the cathode height. Moreover, different electrolytes; sodium bicarbonate (NaHCO3), potassium sulfate (K2SO4), potassium chloride (KCl), sodium sulfate (Na2SO4), along with the electrolyte used in the present study, potassium bicarbonate (KHCO3) have also been experimentally investigated to demonstrate and understand their effects on ECR in detail. The results of the present work can provide useful insights for future experimental research studies on flow cells to adopt optimized operating conditions, consequently improving the overall ECR efficiency. [ABSTRACT FROM AUTHOR]

Polymer bearings used in a real ship had a hydrolysis failure under 50 rpm at 0.5 MPa with 40 °C water temperature. The test conditions were determined based on the operating conditions of the real ship. The test equipment was rebuilt to accommodate bearing sizes in a real ship. Water swelling was eliminated after 6 months' soaking. The results showed that the polymer bearing was subjected to hydrolysis because of the increased heat generation and heat dissipation deterioration under low speed, heavy pressure, and high water temperature. The wear depth in the hydrolysis area is 10 times larger than that in normal wear area, and the melting, stripping, transferring, adhering, and accumulation of hydrolyzed polymers caused abnormal wear. Additionally, extensive cracking was observed in the hydrolysis area of the polymer bearing. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide catalytic activation holds great promise in the treatment of persistent pollutants. In this study, the novel Mn-Acacair/Al, Mn-Acacarg/Al and Mn-BTCarg/Al catalysts, supported on Al2O3, were applied for rapid hydrogen peroxide activation and azithromycin antibiotic removal. The catalysts were prepared by the calcination-hydrothermal method under air or argon atmosphere. The characterization confirmed that the modification of manganese with acetylacetonate and benzene-1,3,5-tricarboxylic acid (H3BTC) O-donor ligands highly improves the catalyst porosity, amorphousity, and abundance of coordinately unsaturated sites, which facilitate the generation of reactive oxygen species. The hydrogen peroxide activation and azithromycin removal reached 98.4% and 99.3% after 40 min using the Mn-BTCarg/Al catalyst with incredible stability and reusability. Only a 5.2% decrease in activity and less than 2% manganese releasing in solutions were detected after five regeneration cycles under the optimum operating conditions. The removal intermediates were identified by LC-MS/MS analysis, and the pathways were proposed. The hydroxylation and decarboxylation reactions play a key role in the degradation reaction. [ABSTRACT FROM AUTHOR]

Astronauts suffer skeletal muscle atrophy in microgravity and/or zero-gravity environments. Artificial muscle-actuated exoskeletons can aid astronauts in physically strenuous situations to mitigate risk during spaceflight missions. Current artificial muscle fabrication methods are technically challenging to be performed during spaceflight. The objective of this research is to unveil the effects of critical operating conditions on artificial muscle formation and geometry in a newly developed helical fiber extrusion method. It is found that the fiber outer diameter decreases and pitch increases when the printhead temperature increases, inlet pressure increases, or cooling fan speed decreases. Similarly, fiber thickness increases when the cooling fan speed decreases or printhead temperature increases. Extrusion conditions also affect surface morphology and mechanical properties. Particularly, extrusion conditions leading to an increased polymer temperature during extrusion can result in lower surface roughness and increased tensile strength and elastic modulus. The shape memory properties of an extruded fiber are demonstrated in this study to validate the ability of the fiber from shape memory polymer to act as an artificial muscle. The effects of the operating conditions are summarized into a phase diagram for selecting suitable parameters for fabricating helical artificial muscles with controllable geometries and excellent performance in the future. [ABSTRACT FROM AUTHOR]

Recent advancements in platinum-group metal-free (PGM-free) catalysts have overwhelmingly prioritized improving initial electrocatalytic activity rather than focusing on catalyst stability. Unfortunately, this emphasis has led to less significant progress in addressing catalyst degradation, ultimately falling well below the level required for commercialization. Shifting the focus towards understanding and mitigating degradation unlocks the true potential of PGM-free catalysts and paves the way for their successful implementation in commercial applications. This work explores methods to mitigate degradation and expand models to predict PGM-free cathode fuel cell degradation due to voltage cycling, specifically current density loss over time. The tested PGM-free cathode fuel cells, using iron (Fe)-based catalyst, were electrochemically characterized before and after the accelerated stress tests (AST) using H 2 /N 2 electrochemical impedance spectroscopy, cyclic voltammetry, and air polarization curves. This study reports the functions of each acceleration factor due to changes in temperature, cycling upper potential limits, and relative humidity are reported. The data indicates that degradation rates increase as temperature, upper potential limit, and relative humidity increase in Fe-based cathode proton exchange membrane fuel cells (PEMFCs). This finding is essential to more accurately quantify losses in active site density with respect to temperature, varying upper potential cycling limit, and relative humidity. More generally, these results can aid in predicting Fe-based cathode fuel cell degradation due to changes in operational conditions. [Display omitted] • Fuel cell operating conditions significantly influence the degradation rate of PGM-free cathodes. • Lowering the temperature from 85°C to 70°C reduces the degradation rate by 65%. • Reducing the upper potential limit from 0.925 V to 0.9 V cuts the degradation rate by 41%. • Decreasing relative humidity from 100% to 60% RH lowers the degradation rate by 43%. [ABSTRACT FROM AUTHOR]

Ce-based thermochemical cycles are characterized by high stability and adaptability to operating temperatures. But few studies have been conducted in terms of exergy prospect. In this study, we propose an exergy analysis model and identify its irreversibility distribution. Through introducing an Energy Level-Enthalpy Change (A-∆H) diagram, we capture this distribution and reveal the trend of irreversibility variation. The results show that irreversibility occurs mainly in heat exchangers and reduction reactors and is influenced by temperature and pressure. Previous studies have focused only on the operating parameters, but this has led to negligible improvement in efficiency, hence the need for a comprehensive analysis using sound mathematical methods. We improve the exergy efficiency by 177% through theoretically optimizing the operating conditions and detail the reasons for the reduction in exergy losses. This study provides theoretical guidance and analytical tools for experiments. • We propose an exergy model to analyze Ce-based solar thermochemical cycles. • We find the irreversibility tendency varying with operating conditions. • We identify the operating conditions achieving the highest exergy efficiency. [ABSTRACT FROM AUTHOR]

[Display omitted] • APR of PET, LDPE and PS plastics was studied, being PET the most prone to be reformed. • Operating conditions of T = 235 °C, pH = 7, using 1.5 % Pt/C maximized H 2 yield. • Increasing reaction time from 4 to 8 h doubled the H 2 yield. • These results suggest that catalytic systems have margin for improvement. Plastic materials are employed in countless applications, resulting in a high amount of waste and the need for alternatives to landfill. In the current work, an alternative to reduce and revalorize waste plastic using direct aqueous-phase reforming (APR), a catalytic process to produce hydrogen and/or alkanes from organic molecules, is proposed with a focus on polyethylene terephthalate. The effect of operating conditions including temperature (190–235 °C), pH (3–12), and the type of metal catalyst and support, was studied. Pt catalysts yielded at 220 °C 5 mmol of H 2 /g of plastic in 4-hour reaction tests, which increased up to 10 mmol of H 2 /g of plastic for an 8-hour reaction time. Additionally, low amounts of short-chain alkanes were detected (<1.4 mmol of alkanes/g of plastic). The production of H 2 was also improved by increasing reaction temperature up to 235 °C, and by using Pt-based bimetallic catalysts and supports with well-developed mesopore area. The results obtained confirm the potential of this strategy as a useful and simple way to transform plastic waste, especially PET, into H 2. [ABSTRACT FROM AUTHOR]

The comprehensive performance of proton exchange membrane fuel cells depends on operating conditions. This paper innovatively uses the Pearson correlation coefficient to screen the optimization objectives (uniformity index of oxygen, standard deviation of temperature, net power density), and obtains the optimal operating conditions of the proton exchange membrane fuel cell through a multi-objective optimization method. The optimized dataset comes from the simulation results of the three-dimensional numerical model, and the regression model is established through the response surface method. Moreover, the non-dominated sorting genetic algorithm-II is used for processing to obtain the Pareto front solution set, and the optimal operating conditions are obtained from it through the Technique for order preference by similarity to an ideal solution. The analysis of variance result shows that the influence of cathode operating conditions on the comprehensive performance is greater than that of anode, especially the influence of cathode stoichiometry ratio is the most significant. The optimal solution obtained 1.0981 %, 10.5845 %, and 1.0376 % enhancement compared to the optimal values in the simulation results. The differences between the three optimization objectives are only 0.8190 %, 1.0315 %, and 0.8789 % as verified by numerical simulation, thus the machine learning results are reliable and accurate. This work combines computational fluid dynamics simulation and machine learning methods to develop high-performance proton exchange membrane fuel cell operating conditions. [Display omitted] [ABSTRACT FROM AUTHOR]

To face the challenges of global water scarcity and water pollution, membrane distillation (MD), represented by hydrophobic microporous membranes, has recently received considerable attention and has shown great potential in processes such as seawater desalination, production of potable water from poor quality water, and wastewater treatment. MD technology has only been implemented in a few pilot plants around the world, a gap that needs to be filled through research and development. The focus of this review is to provide an overview of the effects of operating conditions and the current state of research on the MD process. To further improve the performance of the MD process, three statistical optimization techniques including response surface methodology, evolutionary algorithms, and artificial neural networks for optimizing MD operating parameters are analyzed. Five externally assisted techniques for enhancing the MD process are then reviewed, including electric field, ultrasonic, electromagnetic field, micro bubble aeration, and two-phase flow techniques. Finally, important applications of MD in recent years are discussed, mainly including MD-coupled process applications and thermally positioned solar distillation systems, with the aim of providing new R&D ideas to advance MD technology from emerging to mature. [Display omitted] • Mechanism analysis and optimization methods of MD operating conditions • Process reinforcement methods of MD technology • Important applications and systems integration analysis of MD [ABSTRACT FROM AUTHOR]

• The performance of the four proposed flow field structures were comprehensively compared. • Two novel flow fields partially overcome the limitations of PFF to improve flow distribution and temperature uniformity. • Reducing porous layer porosity and thickness, raising temperature, and lowering inlet flow rate is beneficial for performance. • Four flow fields were quantitatively analyzed using the TOPSIS based on entropy weight method. The proton exchange membrane water electrolyzer (PEMWE) has broad prospects in hydrogen production due to its green and efficient advantages. This paper comprehensively analyzes the performance and water-gas transport characteristics of PEMWE with different cell structures, in which polarization curves, flow velocity distribution, oxygen concentration, temperature, liquid water saturation, and pressure are investigated. Simultaneously, the study explores the effects of variations in inlet velocity, inlet temperature, porosity, and thickness of the anode porous transport layer (APTL) on the four flow fields. Finally, the technique for order preference by similarity to ideal solution (TOPSIS) based on entropy weight method is employed for a comprehensive evaluation of the flow fields. The results indicate that, compared to parallel flow field (PFF), sinusoidal wave flow field (SWFF), intercepted flow field (ICFF), and single-serpentine flow field (SSFF) exhibit stronger exhaust capabilities, with temperature uniformity increasing by 83.65 %, 59.24 %, and 70.15 %, respectively. However, the longer flow channel of SSFF results in a high pressure drop and lower liquid water saturation. An increase in inlet velocity leads to a decrease in temperature, causing an increase in voltage, as higher temperatures reduce activation and ohmic overpotentials. Additionally, an increase in the porosity and thickness of APTL deteriorates the polarization performance of PEMWE. The research results of this study can provide valuable assistance for the future design of PEMWE. [ABSTRACT FROM AUTHOR]

In addition to basicity of CaO, which is suitable for transesterification, synergistic between acidity and hollow structure of ZnFe 2 O 4 support exhibited favorable catalytic activities for esterification of free fatty acids (FFAs), which endowed it to be a heterogenous catalyst with acid-base properties for synthesis of biodiesel from waste frying oil. Hence, magnetic CaO/ZnFe 2 O 4 hollow microspheres heterogenous catalyst was prepared using yeast as green-template by co-precipitation method for synthesis biodiesel from waste frying sunflower oil (WSO). Magnetic CaO/ZnFe 2 O 4 hollow microspheres as an efficient heterogeneous catalyst were characterized by TGA, FESEM, EDX, FT-IR, N 2 adsorption–desorption isotherms and VSM analysis. The use of yeast as green and bio-template increased the surface area and subsequent catalytic activity of magnetic CaO/ZnFe 2 O 4 hollow microspheres significantly higher than CaO/ZnFe 2 O 4. The experimental research shows that the optimal operating conditions for improved catalyst activity were: 30% wt of CaO to ZnFe 2 O 4 hollow structure, calcination temperature of 800 °C and calcination time of 2.5 h. High catalytic performance with 98% biodiesel yield with optimum reaction conditions of 65 °C, 3 h reaction time, 12:1 methanol to oil molar ratio, and 6% wt of catalyst to oil. The CaO/ZnFe 2 O 4 hollow microspheres catalysts possessed magnetic behavior and robust catalyst activity, allowing them to be facilely isolated from the reaction environment and used for five times without notable loss of activity. The effective and novel magnetic CaO/ZnFe 2 O 4 hollow microspheres was prepared. The magnetic CaO/ZnFe 2 O 4 hollow microspheres was used for synthesis biodiesel from waste frying sunflower oil. The CaO/ZnFe 2 O 4 hollow microspheres catalysts possessed magnetic behavior and robust catalyst activity. [Display omitted] [ABSTRACT FROM AUTHOR]

Optimizing traffic signals to improve traffic progression relies on minimizing mobility performance measures (e.g., delays and stops). However, delay and stop minimizations do not necessarily lead to minimal sustainability measures (e.g., fuel consumption and emissions). For that reason, researchers have focused, for decades, on integrating traffic models, signal optimization models, and fuel consumption and emissions models to minimize sustainability metrics while keeping acceptable levels of mobility metrics. Therefore, this paper reviews, classifies, and analyzes studies found in the literature regarding optimizing sustainable traffic signals. This paper provides researchers with a good starting point to further develop solutions which can address sustainable traffic control. To achieve that, this study details the most notable sustainable signal timing optimization studies from six perspectives: traffic models, fuel consumption and emissions models, optimization methods, objective functions, operating conditions, and reported sustainability savings. Outcomes of this research show that the previous studies deployed many combinations of elements from the six-perspective mentioned above, leading to a wide range of fuel consumption and emissions savings. The study also concludes that the available fuel consumption and emissions models are relatively old. Hence, future research is needed to develop new fuel consumption and emissions models based on recently collected data. [ABSTRACT FROM AUTHOR]

Solving the problems of energy saving and efficient use of thermal energy in the construction industry is primarily associated with a number of insufficiently developed scientific and technical problems of urban planning, infrastructure, building thermal physics, such as thermal conductivity and humidity conditions of complex outdoor structures, heat resistance and general heat exchange of a room, air regime buildings, non-stationary joint heat, moisture and air exchange, as well as the durability of the external building envelope. Today, energy saving in urban planning, in the restoration of the destroyed cities and towns of Karabakh, as well as in their further operation, is increasingly relevant due to the high rate of construction of buildings for various purposes, with the deterioration of the environment, the rise in the cost of energy, material and labor resources. Today, world energy is one of the most powerful, actively functioning global systems that determines the most diverse aspects of the life of human society and largely determines the direction and pace of development of the world economy. The paper discusses the application of modern information technologies in solving issues of urban planning, construction and operation of buildings and structures in Karabakh. [ABSTRACT FROM AUTHOR]

PEMFC system is a complex new clean power system. Based on MATLAB/Simulink, this paper develops a system-level dynamic model of PEMFC, including the gas supply system, hydrogen supply system, hydrothermal management system, and electric stack. The neural network fits the electric stack model to the simulation data. The effects of different operating conditions on the PEMFC stack power and system efficiency are analyzed. Combining the power of the reactor and the system efficiency to define the integrated performance index, the particle swarm optimization (PSO) algorithm is introduced to optimize the power density and system efficiency of the PEMFC with multiple objectives. The final optimal operating point increases the power density and system efficiency by 1.33% and 12.8%, respectively, which maximizes the output performance and reduces the parasitic power. [Display omitted] • Build PEMFC system level model in MATLAB/Simulink. • Analyze sensitivity analysis of operating conditions. • Combine stack power and system efficiency to define integrated performance index. • Introduce neural networks and PSO algorithms to optimize system performance. [ABSTRACT FROM AUTHOR]

The uranium reconversion process is performed to convert concentrated UF6 into UO2. Ca(OH)2 is used to neutralize liquid waste generated during the uranium reconversion process, and all waste generated during this process is then collectively named lime waste. The present study aimed to improve cost-effectiveness and efficiency in lime waste treatment by replacing water, required in the cementation process, with concentrated liquid waste. The concentrate/cement ratio in the cementation process was set to range from 1.90 to 2.30, and the content of waste (lime + salt) ranged from 73.4 to 73.5 wt%. The optimum concentrate/cement ratio was determined to be 1.91, considering cost-effectiveness and safety. The structural stability of cement waste forms generated under the optimum operating conditions was evaluated according to the waste acceptance criteria (WAC). The feasibility of waste disposal was demonstrated by the evaluation of the leaching index of Cs, Sr, and Co. [ABSTRACT FROM AUTHOR]

Research on increasing the power density per unit volume by removing and miniaturizing the balance of plants to operate proton exchange membrane fuel cells (PEMFCs) is essential. For drone applications, it is critical to reduce the weight of the PEMFC system. Therefore, the cathode compressor and humidifier are typically removed by directly using atmospheric air, and this operating method is called an open-cathode (OC). However, in the case of the OC-PEMFC, research has not been actively conducted compared to the PEMFC operating using the conventional method. In this study, the effects of various experimental variables on the OC-PEMFC performance are investigated. First, the effects of the flow rate of fans, whether the fan is used or not, operating temperature, humidification of hydrogen, and direction of the cathode opening area on the OC-PEMFC performance are systematically investigated. Second, the effects of substrate thickness of the gas diffusion layer, adding hydrophilic carbon black to the microporous layer, and perforations in the gas diffusion layer, one of the main components in the PEMFC, on the OC-PEMFC performance are identified. Finally, the shapes of endplates that prevent the accumulation of generated water in the cathode opening area are proposed. [ABSTRACT FROM AUTHOR]

In this study, an interfacial slip model including the limiting shear stress is proposed and applied to the thermal elastohydrodynamic lubrication (EHL) analysis of a helical gear pair. The main difference between the proposed model and the classical EHL model is that, the term of entrainment velocity in Reynolds equation is modified. The influences of interfacial slip, thermal effect, initial limiting shear stress and operating conditions on the tribological properties are evaluated. Due to the interfacial slip, the pressure distribution moves towards the inlet region, and the fluctuation distributions of entrainment velocity and film thickness are similar to the trigonometric function. The influence of thermal effect on interfacial slip cannot be ignored, especially in the case of high speed and heavy load. As the input torque and input rotational speed increase, the interfacial slip gradually extends to the whole meshing process. [ABSTRACT FROM AUTHOR]

The supply of species gases and removal of liquid water in a PEM fuel cell are performed through gas flow channels. Therefore, optimising the flow channel configurations is critical for maximising performance of fuel cells. In this paper, the ANSYS PEM Fuel Cell Module is used to simulate a PEM fuel cell with an active area of 100 cm2 and four different flow channel configurations: single-channel serpentine, two-channel serpentine, three-channel serpentine, and parallel channel with headers under two set of different operating conditions. Under both sets of operating conditions, the simulation results indicated that 3-channel serpentine configuration has the best performance due to uniform distribution of species gases over the catalyst layer. It was concluded from the simulation results that the pressure-drop along the 3-channel serpentine configuration is less compared to other serpentine channel configurations, which will require less power for the blowing in of the species gases. The results obtained from simulation under more optimal operating conditions (set 2) used by Hwang's URFC, predicted increase in the performance of all the four channel configurations compared to the set 1 operating conditions due to higher cell temperature and stichometry of inlet gases. Under set 2 operating conditions, the values of pressure drop across all the channel configurations have increased substantially due to higher flow rates of inlet gases. [Display omitted] • 3-channel serpentine is the best performer under both set of operating conditions. • Oxidants are more uniformly distributed over catalyst layer in 3-channel serpentine. • Pressure drop in the single-channel serpentine is higher causing more pumping power. • Pressure drop in channels increases under higher flow rates of species gases. [ABSTRACT FROM AUTHOR]

Micro-direct-methanol fuel cells (μ DMFCs) use micro-electro mechanical system (MEMS) technology, which offers high energy density, portable use, quick replenishment, and free fuel reforming and purification. However, the μ DMFC is limited by a short effective service life due to the membrane electrode's deterioration in electrochemical reactions. This paper presents a health status assessment and remaining useful life (RUL) prediction approach for μ DMFC under dynamic operating conditions. Rather than making external observations, an internal characterization is used to describe the degradation indicator and to overcome intrusive influences in operation. Then, a Markov-process-based usage behavior prediction mechanism is proposed to account for the randomness of real-world operation. The experimental results show that the proposed degradation indicator alleviates the reduction in μ DMFC output power degradation behavior caused by the user loading profile. Compared with the predictions of RUL using traditional external observation, the proposed approach achieved superior prognostic performance in both accuracy and precision. [ABSTRACT FROM AUTHOR]

There is actually an intense research in ethanol dry reforming because bioethanol and carbon dioxide, a greenhouse gas, can be converted into syngas and, in turn, into chemicals and energy such as dihydrogen (H2). Here we review dry reforming of ethanol with focus on thermodynamics, catalysts and effect of operating conditions. Noble metal-based catalysts typically exhibit both ethanol and CO2 conversions above 85% in the range of 923‒1073 K, yet the high cost of precious metals has restrained their potential applications. H2 yield of 90% and above is achieved at 1073 K or above due to the endothermic nature of ethanol dry reforming. Improving catalytic performance and inhibiting coke formation may be achieved by using bimetallic catalysts and other types of metal oxides. [ABSTRACT FROM AUTHOR]

The study investigates tribofilm distribution and tribology performance on piston ring-cylinder liner surfaces under realistic internal combustion (IC) engine conditions. By examining the effects of load, temperature, and oil film thickness ratio, the research reveals that the tribofilm is significantly greater on the cylinder liner surface compared to the piston ring surface. The findings highlight that a specific excitation pressure is necessary for tribofilm formation. An oil film thickness ratio of 1.8041 is evaluated as an accurate boundary for tribofilm distribution on the cylinder liner surface. These insights provide valuable data for designing piston ring-cylinder liner interfaces and improving IC engine performance. [ABSTRACT FROM AUTHOR]

• CO 2 adsorption on Cu, rather than CO 2 transport as in aqueous electrolytes, is revealed to be limiting the electrochemical CO 2 reduction reaction in aprotic electrolytes. • The reported model-assisted analysis provides a quantitative understanding of the kinetics and local reaction environment in unconventional electrolytes. • Operating and design measures are evaluated to improve CO 2 reduction performance. Aprotic organic electrolytes for electrocatalytic CO 2 reduction (CO 2 R) offer a promising yet little-explored alternative to avoid the selectivity issues of alkaline media. We present a model-assisted study of the local reaction environment at a Cu cathode in aprotic organic electrolytes to determine the kinetics of the CO 2 R and the kinetic limitations and reveal their dependence on reaction conditions. The adsorption of CO 2 is identified as the rate-determining step, as opposed to the often-assumed electron transfer during radical anion formation. Unlike alkaline media, there is no transport limitation in aprotic media. Furthermore, our model predicts two strategies to overcome the adsorption limitation: (i) by increasing surface roughness and (ii) by elevating pressure. The findings highlight the critical role of CO 2 adsorption on CO 2 R performance and enable knowledge-driven optimization of reaction conditions and electrocatalysts. [Display omitted] [ABSTRACT FROM AUTHOR]