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As a mainstream power storage and supply device, batteries are continuously upgraded. The microfluidic fuel cell has great development potential, and the paper-based microfluidic fuel cell is the latest achievement of its lightweight, which can be applied in the field of medical and biological detection. In this work, the cell models with various folding forms and unconventional absorption pads are creatively constructed, then the influence mechanism on cell performance is revealed by numerical simulation. Both transient and steady-state simulation methods are employed to monitor the whole process of paper-based microfluidic fuel cell. Conclusions show that the cell performance decreases with the increase of folding angle, the peak power density is as low as 1.71 mW/cm2, and the corresponding fuel utilization is only 2.73%. The changes in the absorbent pad shapes have little improvement on cell performance, thus the most direct way is increasing the absorbent pad volume. Moreover, materials with better water absorption capacity can increase the maximum current density to 28.70 mA/cm2, and the appropriate increase of operating temperature can also increase the peak power density to 2.36 mW/cm2, but the effect on the cell is significantly weakened if the temperature exceeds a certain limit. [ABSTRACT FROM AUTHOR]

A portable paper‐based organic redox flow primary battery using sustainable quinone chemistry is presented. The compact prototype relies on the capillary forces of the paper matrix to develop a quasi‐steady flow of the reactants through a pair of porous carbon electrodes without the need of external pumps. Co‐laminar capillary flow allows operation Under mixed‐media conditions, in which an alkaline anolyte and an acidic catholyte are employed. This feature enables higher electrochemical cell voltages during discharge operation and the utilization of a wider range of available species and electrolytes and provides the advantage to form a neutral or near‐neutral pH as the electrolytes neutralize at the absorbent pad, which allows a safe disposal after use. The effects of the device design parameters have been studied to enhance battery features such as power output, operational time, and fuel utilization. The device achieves a faradaic efficiency of up to 98 %, which is the highest reported in a capillary‐based electrochemical power source, as well as a cell capacity of up to 11.4 Ah L−1 cm−2, comparable to state‐of‐the‐art large‐scale redox flow cells. [ABSTRACT FROM AUTHOR]

Under the dual pressure of energy consumption and environmental pollution, mankind hopes to develop clean and renewable alternative energy, and the rapid development of fuel cells meets people's demand for energy-efficient power systems. The emergence of portable micro energy systems represented by microfluidic fuel cells, such as paper-based microfluidic fuel cells, has greatly enriched the means of medical detection to better cope with the threat of disease transmission. In this work, the numerical simulation method is innovatively introduced to study the paper-based microfluidic fuel cells. Both transient and steady-state modes are employed to demonstrate the whole operation process of the paper-based microfluidic fuel cell. In addition, the different structural parameters, including electrode spacing, the distance between electrode and inlet, channel thickness, and electrode length, are also investigated their influence mechanisms on cell performance. Results show that the increase of most structural parameters decreases cell output power in different degrees. Even on the premise that increasing channel thickness has a positive impact on the output power, the fuel utilization still shows a downward trend. These conclusions provide theoretical support and reference for future optimization work and accelerate the development of microfluidic fuel cells. • Numerical simulation is employed to study paper-based microfluidic fuel cell. • The effects of structure parameters on cell performance are discussed. • Through fuel concentration distribution to reveal cell performance mechanism. • Fuel utilization is used to evaluate energy efficiency. [ABSTRACT FROM AUTHOR]

Coal and biomass are important feedstocks for carbon energy from thermochemical conversion process. Fully understanding the analytical technology that characterizes the changes in physicochemical properties and structural characteristics of coal and biomass during the thermochemical reactions is a key prerequisite for the realization of appropriate utilization of energy fuels. Modern in-situ process analysis technology can accomplish the in-situ detection of the experimental process, and therefore reflect the experimental process more accurately. Moreover, it is developing towards automation, intelligentization, and comprehensive detection. Based on the characteristics of each detection technology, this paper summarizes the basic principles, application scope and performance characteristics of the three advanced in-situ process analysis technologies: hyphenated technology, synchrotron radiation, and online analysis. The practicability and accuracy of each detection technology in coal and biomass research are compared and analyzed, and its latest application and development trend are elucidated. These tools not only make up for the shortcomings of traditional detection techniques in characterizing the in-situ reaction, but also provide complementary information on molecular microscopic changes during fuel thermal conversion. This review paper can provide insights for relevant researchers in the selection of analytical techniques, and promote in-depth study on microcosmic mechanism of fuel conversion. [ABSTRACT FROM AUTHOR]

Summary: Microchannel geometry, electrode surface area, and better fuel utilization are important aspects of the performance of a microfluidic fuel cell (MFC). In this communication, a membraneless spiral‐shaped MFC fabricated with Ni as anode and C as a cathode supported over a porous filter paper substrate is presented. Vanadium oxychloride and dilute sulfuric acid solutions are used as fuel and electrolyte, respectively, in this fuel cell system. The device generates a maximum open‐circuit voltage of ~1.2 V, while the maximum energy density and current density generated from the fuel cell are ~10 mW cm−2 and ~51 mA cm−2, respectively. The cumulative energy density generated from the device after five cycles are measured as ~200 mW after regeneration of the fuel by applying external voltage. The spiral design of the fuel cell enables improved fuel utilization, rapid diffusive transport of ions, and in‐situ regeneration of the fuel. The present self‐standing spiral‐shaped MFC will eliminate the challenges associated with two inlet membrane‐less fuel cells and has the potential to scale up for commercial application in portable energy generation. [ABSTRACT FROM AUTHOR]

Developing high-efficiency and low-carbon propulsion systems is a pressing concern within the aviation field. This paper studies a hybrid power system that combines a solid oxide fuel cell and a gas turbine (SOFC-GT) with propane as fuel, which is easy to store and has a high energy density. The analysis focuses on key parameters such as compressor pressure ratio, fuel utilization rate, and fuel distribution. And a balance between system efficiency and the power-to-weight ratio has been achieved through multi-objective optimization. The conclusions indicate that system efficiency and system weight in the hybrid power system are optimized in opposite directions. Within the design parameters, the hybrid power system's efficiency achieves 0.621, the specific fuel consumption is 115.2 g/kWh, and the power-to-weight ratio is 0.569 kW/kg. Further discussion on the application of this hybrid system in long-endurance unmanned aerial vehicles shows an efficiency of 0.651 during the cruise phase, indicating a promising application prospect of a propane-fueled SOFC-GT hybrid system in the aviation field. [ABSTRACT FROM AUTHOR]

Singapore has committed to achieving net zero emissions by 2050, which requires the pursuit of multiple decarbonization pathways. CO 2 utilization methods such as fuel production may provide a fast interim solution for carbon abatement. This paper evaluates the feasibility of green hydrogen-based synthetic fuel (synfuel) production as a method for utilizing captured CO 2 . We consider several scenarios: a baseline scenario with no changes, local production of synfuel with hydrogen imports, and overseas production of synfuel with CO 2 exports. This paper aims to determine a CO 2 price for synfuel production, evaluate the economic viability of local versus overseas production, and investigate the effect of different cost parameters on economic viability. Using the current literature, we estimate the associated production and transport costs under each scenario. We introduce a CO 2 utilization price (CUP) that estimates the price of utilizing captured CO 2 to produce synfuel, and an adjusted CO 2 utilization price (CCUP) that takes into account the avoided emissions from crude oil-based fuel production. We find that overseas production is more economically viable compared to local production, with the best case CCUP bounds giving a range of 142–148 $/t CO 2 in 2050 if CO 2 transport and fuel shipping costs are low. This is primarily due to the high cost of hydrogen feedstock, especially the transport cost, which can offset the combined costs of CO 2 transport and fuel shipping. In general, we find that any increase in the hydrogen feedstock cost can significantly affect the CCUP for local production. Sensitivity analysis reveals that hydrogen transport cost has a significant impact on the viability of local production and if this cost is reduced significantly, local production can be cheaper than overseas production. The same is true if the economies of scale for local production is significantly better than overseas production. A significantly lower carbon capture cost can also the reduce the CCUP significantly. [ABSTRACT FROM AUTHOR]

Circulating fluidized bed (CFB) boilers offer a technically viable and environmentally friendly means for the clean and efficient utilization of solid fuels. However, the complex gas–solid two-phase flow processes within them have hindered a thorough resolution of prediction issues related to coupled combustion, heat transfer, and pollutant generation characteristics. To address the deficiencies in scientific research, meet the practical operational needs of CFB boilers, and comply with new carbon emission policies, conducting full-scale field tests on large-scale CFB boilers is needed, so that the complex gas–solid flow, combustion, and heat transfer mechanisms in the furnace can be comprehended. In this paper, issues related to large-scale CFB boilers, including the uniformity of air distribution, secondary air injection range, spatial distribution of oxygen consumption and combustion reactions, distribution of pollutant generation, hydrodynamic and heat transfer characteristics, coal feeding distribution characteristics, coal diffusion characteristics under thermal operating conditions, and engineering research on anti-wear technology, are reviewed. By integrating practical engineering applications, the basic methods and measurement techniques used in full-scale field tests for large-scale CFB boilers are summarized, providing a practical reference for conducting engineering tests with large-scale CFB boilers. [ABSTRACT FROM AUTHOR]

The rotary engine (RE) is a potential power plant for unmanned aerial vehicles (UAVs) and automobiles because of its structural and design merits. However, it has some serious drawbacks, such as frequent maintenance requirements and excessive fuel consumption. This review paper presents the current status of hydrogen-fueled rotary engine (HRE) technology and identifies the existing research and development gaps in combustion efficiency and performance of this engine that might benefit transportation sector. Focusing primarily on the research from past ten years, the crucial challenges encountered in hydrogen-powered rotary engines have been reviewed in terms of knock, hydrocarbon (HC) emissions, and seal leakages. The paper identifies the recent advances in design concepts and production approaches used in hydrogen-fueled rotary engines such as geometric models of trochoid profiles, port configurations, fuel utilization systems, and currently available computational fluid dynamics (CFD) tools. This review article is an attempt to collect and organize literature on existing design methods up to date and provide recommendations for further improvements in RE technology. [ABSTRACT FROM AUTHOR]

The utilization of fuel cells (FC) in automotive technology has experienced significant growth in recent years. Fuel cell hybrid electric vehicles (FCHEVs) are powered by a combination of fuel cells, batteries, and/or ultracapacitors (UCs). By integrating power converters with these power sources, the FCHEV system can overcome the limitations of using them separately. The performance of an FCHEV is influenced by the efficiency of the power electronics converter controller, as well as the technical efficiency of the power sources. FCHEVs need intricate energy management systems (EMSs) to function effectively. Poor EMS can lead to low efficiency and accelerated fuel cell and battery degradation. The literature discusses various types of EMSs such as equivalent consumption minimization strategy, classical PI controller, fuzzy logic controller, and mutative fuzzy logic controller (MFLC). It also discusses a systematic categorization of FCHEV topologies and delves into the unique characteristics of these topologies. Furthermore, it provides an in-depth comparative study of EMSs applied in FCHEVs, encompassing rule-based, optimization-based, and advanced learning-based approaches. However, comparing different EMSs can be challenging due to the varying vehicle and system parameters, which might lead to false claims being made regarding system performance. This review aims to categorize and discuss the various topologies of FCHEVs, highlighting their pros and cons, and comparing several EMSs based on performance metrics such as state of charge (SOC) and FC deterioration. This paper seeks a deeper comprehension of the recent advancements in EMSs for FCHEVs. It offers insights that can facilitate a more comprehensive grasp of the current state of research in this field, aiding researchers in staying up to date with the latest developments. [ABSTRACT FROM AUTHOR]

The performance of ammonia hydrogen fuel cells (AHFCs) with the same activated area but different aspect ratio is quite different. In this paper, based on the diffusion characteristics of hydrogen nitrogen mixture, five different aspect ratios of AHFCs were designed, and the influence of aspect ratio on the performance of AHFCs was studied by combining experiment and simulation analysis. The results reveal that the power of AHFCs reaches the maximum when the aspect ratio is 1, that is, the shortest hypotenuse of the plate. With the extension of the hypotenuse, the output power decreases, and the output power decreases by 19.3% when the aspect ratio is 4. Due to the strong ability of hydrogen diffusion, when the aspect ratio of AHFCs is 4, the proportion of hydrogen and oxygen starvation area at the interface reaches the maximum and minimum, which are 11.8% and 0.3% respectively, which is contrary to the aspect ratio of 0.25. A larger aspect ratio is conducive to the uniform distribution of gas-water-heat. Although the AHFCs with aspect ratio of 0.64 has advantages in power generation efficiency and fuel utilization, the pressure drop loss increases by 43.7%, and the pressure drop loss with aspect ratio of 0.25 increases by 141.2%. • Experimental data of AHFCs with different aspect ratios are obtained. • Power generation efficiency of AHFCs with different aspect ratios is compared. • AHFC with the shortest hypotenuse has the largest output power. • CV is used to characterize the uniformity of gas-heat-water distribution in AHFC. [ABSTRACT FROM AUTHOR]

Intake parameters are essential factors that are often overlooked, but can easily change the direct internal reforming solid oxide fuel cell (DIR-SOFC) performance. A three-dimensional model is developed to simulate the effects of intake parameters on the performance of an anode-supported flat-plate DIR-SOFC. The two primary chemical reactions, water gas shift reaction (WGSR) and methane steam reforming reaction (MSR), as well as the electrochemical oxidation of H 2 and CO, are considered in this model. It was found that the aspect ratio corresponding to the peak current density decreases as fuel increases. A moderate air flow rate makes the fuel-to-air ratio (FAR) corresponding to the drastic change in current density relatively small and wide-ranging, resulting in more desirable temperature distribution and fuel utilization. Under the operating conditions of this paper, adjusting the steam-to-carbon ratio (S/C) to between 1.5 and 2 results in both excellent electrical performance and good temperature uniformity. Additionally, adjusting the flow rate by changing the inlet area or velocity has its own advantages in terms of temperature distribution or current density, which must be taken into account when adjusting the flow rate. This study provides a valuable reference on inlet settings of DIR-SOFC, which would help to promote the development of high-performance SOFCs. • A three-dimensional flat-plate DIR-SOFC model has been developed. • Oxidation reaction of CO is included in the mode. • Different flow rates would change the effects of the aspect ratio and S/C. • Impacts of the fuel-air ratio are analyzed fully in terms of both fuel and air sides. • Changing the flow rate by altering the area or speed can make differences. [ABSTRACT FROM AUTHOR]

Membraneless microfluidic fuel cell (MMFC) has potential application prospects in micro-devices due to the characteristics of considerable output performance, superior cleanliness and easy miniaturization. Whereas, the performance of MMFC is restricted by the mass transfer of two-phase flow, which manifests as the inefficiency transportation in liquid phase and obstruction of gas phase. This paper proposes a novel sinusoidal corrugated channel (SCC) for MMFC though developing a three-dimensional two-phase model by coupling the multi-physics field to improve the cell performance in mass transfer, and further studies the two-phase flow characteristics of geometric parameters of SCC, including the amplitude A and angular frequency ω. Based on the optimal configuration in A of 0.5 mm and ω of 3 rad s−1, compared with the conventional straight channel, the increase ratios of maximum current density, power density, fuel utilization are 13.69%, 8.39% and 13.72%, respectively. Additionally, the gas volume fraction at the maximum power density decreases by 12.62%. This paper provides new insights and theoretical foundations for the study of MMFC flow field configurations, and furnishes references for the mass transfer intensification. [ABSTRACT FROM AUTHOR]

The anode recirculation mode is increasingly being adopted in today's fuel cell systems. The recycling of hydrogen gas can effectively improve fuel utilization and the wider economy. However, using the purge strategy for the recirculation exhaust has a significant impact on the operational performance and economic efficiency of fuel cell systems.Experiments have shown that, when the purge interval increases from 6 s to 10 s, the recirculation pump power increases by about 20%, the nitrogen content in the exhaust gas increases, and the stack voltage shows a 10 V attenuation. The accumulation of nitrogen permeation in the anode circuit leads to the degradation of the fuel cell performance. Therefore, it is necessary to discharge the accumulated nitrogen through the purge valve in a timely manner. However, opening the exhaust valve with excessively high frequency can result in the unreacted hydrogen being discharged, which reduces the economic efficiency of the fuel cell. This paper is based on the principle of mass conservation and models each subsystem of the anode circuit in the recirculation pump mode of the fuel cell separately, including the proportional valve model, the hydrogen consumption model of the fuel cell, the nitrogen permeation model of the fuel cell, the neural network model of the circulating pump, and the purge valve model. These submodels are integrated to construct a nitrogen content observer for the hydrogen circuit, which can estimate the nitrogen content. The accuracy of the model is validated through experimental data. The estimation error is less than 5.5%. The nitrogen content in the anode circuit can be effectively estimated, providing a model reference for purge operations and improving hydrogen utilization. [ABSTRACT FROM AUTHOR]

Once-through molten salt reactors have the advantages of easy availability of fuel, nuclear nonproliferation, and low technical difficulty. It is expected to be the earliest commercial molten salt reactor fuel cycle mode. The current research on the neutronic performance of the once-through fuel cycle mainly focuses on the thermal spectrum range, and broader spectrum research needs to be carried out further. In particular, the fuel utilization characteristics of molten salt fast reactors in once-through fuel cycle are not yet clear. In addition, small modular design is one of the trends of molten salt reactor development, and small modular design under thermal and fast spectrum has different advantages and needs further comparative analysis. In this paper, the single lattice, bare reactor, and core with reflector models are used to compare the neutronic performance in once-through fuel cycle from thermal to fast spectrum, which includes burnup, variation of fuel salt composition and volume with burnup, temperature reactivity coefficient, neutron irradiation lifetime, and small modular size. The results show that the burnup increases first, then decreases, and then increases again with the increase of the average lethargy causing fission (EALF). For small-scale molten salt reactors, the difference in fuel utilization under thermal and fast spectra is small. However, for large-scale reactors, the burnup under fast spectrum is significantly higher than that under thermal spectrum. When the EALF is large enough, and the neutron loss ratio is small enough, the breed-and-burn (BNB) fuel cycle mode can be realized, and then, the fuel utilization will be significantly improved. In the fast spectrum reactors, the HN and volume of molten salt change violently because of the longer burnup period. Based on the infinite single lattice model, the temperature reactivity coefficient increases first, then decreases, and increases again with EALF. It is negative over the entire energy spectrum. In addition, the small modular designs are discussed by the bare reactor model, and the neutron irradiation lifetime of the materials is analyzed by the core model with a reflector. [ABSTRACT FROM AUTHOR]

Both anode off‐gas recirculation (AOGR) and cathode off‐gas recirculation (COGR) can increase the performance of solid oxide fuel cell‐combined heat and power (SOFC‐CHP) systems on their own, however, they both have unavoidable drawbacks. Thus, the combined effect of both on the system is worth investigating. The essential challenge is to figure out what the best AOGR and COGR ratios are under the combined situation. In this paper, the effects of varied AOGR ratios and COGR ratios on the system performance were investigated. A model of a 1 kW natural gas‐fueled SOFC‐CHP system was constructed which uses Cycle‐Tempo software. It is demonstrated that moderate AOGR can improve the net electrical efficiency, but too much AOGR will reduce the H2 concentration at the anode inlet and prevent the stack from working properly; moderate COGR can improve the thermal efficiency, but too much COGR can lead to large changes in current density variation and cause drastic changes in current, which affects the system and external electrical equipment. While, combining AOGR with COGR can improve both the net electrical and thermal efficiency, which results in higher total efficiency. As a result, the combined configuration of an AOGR ratio of 0.4 and a COGR ratio of 0.4 is recommended. In this scenario, the net electrical efficiency of the system is 47.38%, the thermal efficiency is 28.98%, the total efficiency is 76.37%, and the actual fuel utilization rate is 0.834. [ABSTRACT FROM AUTHOR]

Recently, the growing demand for a renewable and sustainable fuel alternative is contingent on fuel cell technologies. Even though it is regarded as an environmentally sustainable method of generating fuel for immediate concerns, it must be enhanced to make it extraordinarily affordable, and environmentally sustainable. Hydrogen (H2) synthesis by electrochemical water splitting (ECWS) is considered one of the foremost potential prospective methods for renewable energy output and H2 society implementation. Existing massive H2 output is mostly reliant on the steaming reformation of carbon fuels that yield CO2 together with H2 and is a finite resource. ECWS is a viable, efficient, and contamination‐free method for H2 evolution. Consequently, developing reliable and cost‐effective technology for ECWS was a top priority for scientists around the globe. Utilizing renewable technologies to decrease total fuel utilization is crucial for H2 evolution. Capturing and transforming the fuel from the ambient through various renewable solutions for water splitting (WS) could effectively reduce the need for additional electricity. ECWS is among the foremost potential prospective methods for renewable energy output and the achievement of a H2‐based economy. For the overall water splitting (OWS), several transition‐metal‐based polyfunctional metal catalysts for both cathode and anode have been synthesized. Furthermore, the essential to the widespread adoption of such technology is the development of reduced‐price, super functional electrocatalysts to substitute those, depending on metals. Many metal‐premised electrocatalysts for both the anode and cathode have been designed for the WS process. The attributes of H2 and oxygen (O2) dynamics interactions on the electrodes of water electrolysis cells and the fundamental techniques for evaluating the achievement of electrocatalysts are outlined in this paper. Special emphasis is paid to their fabrication, electrocatalytic performance, durability, and measures for enhancing their efficiency. In addition, prospective ideas on metal‐based WS electrocatalysts based on existing problems are presented. It is anticipated that this review will offer a straight direction toward the engineering and construction of novel polyfunctional electrocatalysts encompassing superior efficiency in a suitable WS technique. [ABSTRACT FROM AUTHOR]

The subject of this paper is utilization of corn cobs as a fuel in small residential heating appliances in Serbia. The objective was to investigate the profitability of the three cob forms: whole, crushed, and pellets. Thereby, construction and reconstruction option of a heating system that uses corn cobs were compared with woody and fossil fuel forms. Net present values of generated costs in the first option, as well as net present value of savings, payback period, and internal rate or return in the second, were analyzed. Assessment was conducted using BIOMASAPRO calculator with integrated approach for energy facility investments. Only utilization of whole cobs were profitable, comparing with wood logs, coal, and natural gas. In option construction, around 8700 €, 7000 €, and more than 4100 € could be thus saved after the appliance lifespan, respectively. The savings could be 7800 €, 5500 €, and more than 3600 € in option reconstruction, with payback period less than two years compared with wood logs and coal, and around 2.5 years with natural gas. Sensitivity analysis showed that utilization of whole cobs could be profitable with up to three times higher purchase price. With bank loan as a financing option for economically weaker biomass users, the scenarios though remain profitable. Subsidy of more than 40% for a heating appliance that uses crushed cobs would allow for profitable investment in comparison with wood chips. Future investigation should comprise assessment including social and environmental aspects, to conclude if corn cobs are a sustainable fuel in Serbia. [ABSTRACT FROM AUTHOR]

Having in mind that energy is being regarded as indispensable to the socioeconomic progress of developing and developed nations, where the main objective implies replacement and reduction of a major portion of the fossil fuels utilization, implementation of renewable energy technologies where natural phenomena are transformed into beneficial types of energy are becoming more and more appreciated and needed. Among renewable energy resources we know today, solar energy is the most beneficial, relatively limitless, effective, and dependable. Having this in mind, the aim of this paper is primarily to help key decision-makers understand the process when considering integration of solar energy to meet their own manufacturing energy needs, or how it is called today, to become "prosumers". Given the aforementioned, this paper provides an overview of detailed simulation methodology for photovoltaic system sizing and design for metal- forming manufacturing system energy needs. The simulation is based on National Renewable Energy Laboratory photovoltaic performance model which combines module and inverter sub-models with supplementary code to calculate a photovoltaic power system's hourly AC output is given a weather file and data describing the physical characteristics of the module, inverter, and array. Furthermore, the characteristic losses are calculated and presented for a fixed array photovoltaic system and illustratively given in the form of a Sankey diagram. A variety of graphical data representations are available while the most important ones are given in the study. Lastly, future research topics were filtered and briefly summarized. [ABSTRACT FROM AUTHOR]

Spent carbon anodes (SCAs) possess significant environmental risks and secondary resource properties. The current flotation method for recovering valuable components exhibits suboptimal purity and efficiency. This paper focuses on the extraction of valuable components from SCAs via mechanical activation-assisted flotation. Flotation parameters were optimized under mechanical activation intensification. Subsequently, the effects of flotation parameters on the flotation rate were explored. The enhancement mechanism of flotation via mechanical activation was quantified and proposed from a kinetic perspective. Results demonstrated that the activated SCA exhibited higher carbon content and flotation rate constant compared with the unactivated samples under identical flotation parameters. The selection and sweeping processes of SCA flotation were further determined, and a complete closed-circuit flotation process was established. Results demonstrated that the carbon content and recovery rate of the extracted carbon concentrate achieved 90.58% and 77.87% by mechanical activation-assisted flotation, respectively. Finally, numerous characterization techniques were used to characterize the recovered carbon concentrate. Recovered carbon is suitable for resource utilization as a fuel and carbon enhancer because of its high carbon content and low sulfur content. The proposed method of mechanical activation-assisted flotation is anticipated to serve as the primary approach for extracting valuable components from SCAs. [ABSTRACT FROM AUTHOR]

Developing novel solid oxide fuel cells (SOFCs) with high stability running at low temperatures is an important objective in SOFC science. In the current paper, a comprehensive physics-based microstructure modeling using scanning electron microscope (SEM) image analysis was performed on several anode-support SOFCs operating at low temperatures with high stability. To bridge the gap in the literature regarding an accurate and realistic modeling, a new model was developed based on the variable fuel and air utilization factors and updated microstructure values (e.g., tortuosity, porosity, pore size, grain size). The model accuracy was verified by a thorough point-to-point validation for eight different cells with the configuration of Ni-YSZ (anode), YSZ (electrolyte), and GDC/PNO (cathode). Different temperatures, hydrogen, and air mass flow rates were used, for which an average error of less than 3% in the I-V curves was achieved. The microstructure of the cells, including cathode thickness (15–26 μm), anode-support thickness (350–460 μm), porosity (39 and 43%), grain size (1.1–1.4 μm), and pore radius (0.9–1.1 μm) were varied. Moreover, the effects of the critical operational and design parameters on the overpotential losses and cell performance were studied. The results show that a hydrogen flow rate of 43 sccm was ideal when the cell operated at 0.9 A/cm2 and 700 °C. Moreover, an average anode-support pore radius of 1.75 μm resulted in the best cell performance. It was also concluded that the electrolyte thickness has a higher effect on the cell performance compared to the cathode thickness. • Fabrication and testing of eight anode-supported tublar cells with different microstructures. • Introducing a physics-based microstructure model for SOFC based on variable fuel utilization factor. • Performing a comprehensive SEM image analysis for the fabricated cells. • Achieving an average error of less than 3% for the model compared to the experimental data. • Achieving an average optimum value of 1.75 μm for anode-support pore radius. [ABSTRACT FROM AUTHOR]

The work is devoted to the development of a thermal scheme for the conversion of a cogeneration power plant to threegeneration with the production of hydrogen as a new product. The purpose of the work is to assess the possibility and potential of hydrogen production from MSW at the existing thermal power plants of St. Petersburg. To achieve this goal, it is necessary to develop a methodology for selecting the site of an existing thermal power plant in order to integrate a hydrogen production complex by the MSW gasification method, as well as a methodology for estimating the amount of hydrogen that can potentially be obtained from a given amount of MSW. The research methods include simulation of the thermal circuit of a steam power plant in the United Cycle program. The paper proposes an algorithm for selecting the site of an operating thermal power plant for the integration of a complex for the production of hydrogen by the method of MSW gasification. The algorithm can be applied to any subjects of the Russian Federation, and its relevance is confirmed by strategic documents. Potential locations for the new TPP are being considered in the territories of TPP-21 and TPP-22, which have the necessary resources and good infrastructure. As a result of the study, the site of TPP-22 was selected as the most suitable for the placement of new facilities. A new thermal scheme of a threegeneration power plant has been developed, including a hydrogen generation unit by the MSW gasification method. This allows the production of hydrogen in parallel with the production of electricity and heat. The efficiency evaluation criterion is the fuel heat utilization factor (FHUF). Regardless of the hydrogen content in the generated synthesis gas, the integration of the synthesis gas cooler into the thermal circuit of the TPP leads to an increase in the FHUF and an additional energy effect. This scheme increases the efficiency of existing TPP plants, regardless of the morphological composition of municipal solid waste. [ABSTRACT FROM AUTHOR]

Although button solid oxide fuel cells (SOFCs) have been extensively used in fundamental research, practical commercial applications are developed on industrial-sized SOFCs. As the active area and fuel utilization increase, some issues that are not considered in button cells become essential. Therefore, it is necessary to focus on the differences between button cells and industrial-sized cells, including their polarization characteristics and performance evaluation. In this study, the polarization curves of both types of cells under different hydrogen flow rates are tested. Both types of cells experience a sudden increase in total area-specific resistance (R tot) under high current density. However, the effects of hydrogen flow rate differs between cell types. Based on the equivalent circuit model (ECM) fitting of electrochemical impedance spectroscopy (EIS) measured under different DC biases and the theoretical calculation of gas diffusion and gas conversion resistances, it is demonstrated that the rapid increase in R tot in button cells is primarily attributed to gas diffusion through the anode. In contrast, non-uniform gas distribution along the flow channel direction results in a dominant role of gas conversion resistance on R tot in industrial-sized cells, especially at hydrogen flow rates below 0.4 L min−1. Although electrical efficiency is often overlooked in button cells, it is a crucial performance evaluation index in industrial-sized cells. The impact of operating parameters on power density and electrical efficiency is analyzed, revealing a trade-off between the two. With the critical Nernst electromotive force of Ni oxidation as the voltage lower limit, the optimal operating conditions with high electrical efficiency and prevention of Ni oxidation under different flow rates are obtained. It is investigated that operation should be carried out at a low flow rate below 0.3 L min−1 to achieve high electrical efficiency of over 50%. The selected operating parameters will change when the cell performance or load demand changes. However, the analysis method proposed in this paper can still provide a reference for selecting the operating parameters of a SOFC system. • Comparison of polarization characteristics between button and industrial-sized SOFCs. • Dominant process of polarization in industrial-sized cells varies at different flow rates. • High voltage at high fuel utilization with low flow rate prevents Ni oxidation. [ABSTRACT FROM AUTHOR]

Molten salt reactors (MSRs) are one type of GEN-IV advanced reactors that adopt melt mixtures of heavy metal elements and molten salt as both fuel and coolant. The liquid fuel allows MSRs to perform online refueling, reprocessing, and helium bubbling. The fuel utilization, safety, and economics can be enhanced, while some new physical mechanisms and phenomena emerge simultaneously, which would significantly complicate the numerical simulation of MSRs. The dual roles of molten fuel salt in the core lead to a tighter coupling of physical mechanisms since the released fission energy will be absorbed immediately by the molten salt itself and then transferred to the primary heat exchanger. The modeling of multi-physics coupling is regarded as one important aspect of MSR study, attracting growing attention worldwide. Up to now, great efforts have been made in the development of MSR multi-physics coupling models over the past 60 years, especially after 2000, when MSR was selected for one of the GEN-IV advanced reactors. In this paper, the development status of the MSR multi-physics coupling model is extensively reviewed in the light of coupling models of N-TH (neutronics and thermal hydraulics), N-TH-BN (neutronics, thermal hydraulics, and burnup) and N-TH-BN-G (neutronics, thermal hydraulics, burnup, and graphite deformation). The problems, challenges, and development trends are outlined to provide a basis for the future development of MSR multi-physics coupling models. [ABSTRACT FROM AUTHOR]

This paper addresses decentralized control of a hybrid energy system consisting of a fuel cell (FC) and an ultracapacitor. Separate controllers are developed for the FC and the ultracapacitor for power management rather than one central controller. Explicit communication between controllers, such as exchange of locally sensed information, is absent. The former operates the FC in a load-following mode, while attenuating transient fluctuations in fuel utilization. The latter allows the ultracapacitor to be used as an energy buffer. The paper proposes a simple energy-conservation-based approach where the FC controller estimates the energy gap that is compensated for by the capacitor, based on its own transient response history. Accordingly, it modulates its own output power. The capacitor control, in turn, imparts robustness to the collective performance of the controllers by either dissipating excess energy or regulating the load voltage. Together, synergistic power management is achieved within a decentralized framework. An experimental test stand is developed to validate the approach and experimental results are provided. This paper considers one power source and one energy storage element, and further research must be done to translate this approach to power networks. [ABSTRACT FROM AUTHOR]

Hydrogen-diesel dual fuel (HDDF) technology is one approach available to improve the performance and reduce carbon-based emissions of compression ignition (CI) engines. Unfortunately, when operated at partial and low loads, HDDF engine configurations suffer from poor fuel utilization, combustion efficiency and ignition delay. As partial load application is increasingly important to performance of hybrid power systems, this paper explores the use of oxygen enrichment to improve HDDF performance outside of conventional load applications. In this paper, a numerical model was first developed and validated for HDDF combustion using experimental data. This model was subsequently applied to study the influences of oxygen enrichment on engine performance and emission characteristics. Furthermore, the Exhaust Gas Recirculation (EGR) was implemented as a secondary control for NOx emission reduction. For this configuration the results showed that oxygen enrichment (between 21% and 27% by volume) into the intake manifold led to an improved combustion efficiency and reduced carbon-based emissions. The brake thermal efficiency (BTE) increased by 1.6% and the brake specific energy consumption decreased by 4%. Across the emissions spectrum, soot emission reduced by 72%, whereas NOx emission increased by 63% without using the EGR technique. By combining oxygen enrichment and EGR strategies, a considerable reduction of 79% in NOx and an increase of 2.6% in BTE was observed for the oxygen concentration of 27% and EGR rate of 24% compared to a conventional HDDF operation with 45% HES ratio. [Display omitted] • Effect of oxygen enrichment on hydrogen dual-fuel engine performance was studied. • Thermal efficiency of dual-fuel engines was improved by oxygen enrichment. • Oxygen enrichment reduced carbon-based emissions and increased NOx emissions. • EGR significantly reduced NOx emissions and slightly increased system efficiency. • Combined EGR and oxygen enrichment techniques largely improved engine performance. [ABSTRACT FROM AUTHOR]

Vehicular Ad hoc Network (VANET) has become an integral part of Intelligent Transportation Systems (ITS) in today's life. VANET is a network that can be heavily scaled up with a number of vehicles and road side units that keep fluctuating in real world. VANET is susceptible to security issues, particularly DoS attacks, owing to maximum unpredictability in location. So, effective identification and the classification of attacks have become the major requirements for secure data transmission in VANET. At the same time, congestion control is also one of the key research problems in VANET which aims at minimizing the time expended on roads and calculating travel time as well as waiting time at intersections, for a traveler. With this motivation, the current research paper presents an intelligent DoS attack detection with Congestion Control (IDoS-CC) technique for VANET. The presented IDoSCC technique involves two-stage processes namely, Teaching and Learning Based Optimization (TLBO)-based Congestion Control (TLBO-CC) and Gated Recurrent Unit (GRU)-based DoS detection (GRU-DoSD). The goal of IDoS-CC technique is to reduce the level of congestion and detect the attacks that exist in the network. TLBO algorithm is also involved in IDoS-CC technique for optimization of the routes taken by vehicles via traffic signals and to minimize the congestion on a particular route instantaneously so as to assure minimal fuel utilization. TLBO is applied to avoid congestion on roadways. Besides, GRU-DoSD model is employed as a classification model to effectively discriminate the compromised and genuine vehicles in the network. The outcomes from a series of simulation analyses highlight the supremacy of the proposed IDoS-CC technique as it reduced the congestion and successfully identified the DoS attacks in network. [ABSTRACT FROM AUTHOR]

By reducing fossil fuel use, renewable energy improves the economy, quality of life, and environment. These impacts make renewable energy forecasting crucial for lowering fossil fuel utilization. This paper aims to mathematically improve time series forecasting literature by focusing on solar irradiance applications in Los Angeles, Denver, and Hawaii solar irradiance sites. A three-phased time series forecasting hybrid method is devised for this endeavor. The ARFIMA is used to forecast the original solar irradiance time series in phase I. Next, the dataset's residuals, are retrieved by subtracting the phase I results from the observed time series to prepare the scenario for the following phase. A novel enhanced fractional Brownian motion is used for residual forecasting in phase II. The parameter estimation in phase II is implemented adaptively to capture the dynamic statistical characteristics of the time series efficiently. Finally, the phases I and II results are numerically conglomerated to form the final forecasting results in phase III. The residual forecasting part, in phase II, reveals a substantial superiority. Also, when comparing the proposed hybrid algorithm results to other existing cutting-edge algorithms applied to the same solar irradiance applications, the output demonstrates that the suggested algorithm has a significantly improved performance. [ABSTRACT FROM AUTHOR]

In this paper, fuel composition and efficiency of solid oxide fuel cell with different methanol pretreating technologies are investigated. High concentrations of H2 and CO can be produced by methanol pretreatment at high temperature, whereas high concentration of methane can be produced at low temperature under the thermodynamic equilibrium condition. For steam reforming of methanol, high cell efficiency can be obtained, whereas for partial oxidation of methanol, the cell efficiency decreases most obviously compared with other pretreating technologies with the increase of O/C ratio. When the O/C ratio is 1.5, the cell efficiencies are 55.89% for steam reforming of methanol, 50.83% for autothermal reforming of methanol, and 45.77% for partial oxidation of methanol at 80% equivalent fuel utilization and 1073 K. When the O/C ratio increases to 2.5, the cell efficiency decreases slowly to 52.01% for steam reforming of methanol, whereas rapidly to 21.68% for partial oxidation of methanol at 80% equivalent fuel utilization and 1073 K. According to the calculated results under the thermodynamic equilibrium condition, suitable pretreating technology and O/C ratio for methanol pretreatment can be selected for the operation of solid oxide fuel cell, which can lead to the high efficiency and good stability of solid oxide fuel cell. [ABSTRACT FROM AUTHOR]

In the last few decades, the utilization of fuel cells (FCs) in the automotive industry has created much attention due to easy use, modular structure, and higher efficacy. In the future, technological evolutions reveal that FC driven electric vehicles (EVs) will grow at a rapid pace and will become an excellent alternative to conventional vehicles. This paper discusses a detailed topological classification of the FC‐based hybrid electric vehicle (FCHEV). In these FCHEVs, one of the critical elements is the DC–DC power converter unit. The hybridization of FCs with the other power sources requires more converter units that make the system complex. A multi‐input DC–DC power converter is used to connect more than one energy source to reduce the system's complexity and improve the overall system efficacy. In this survey, numerous articles have been considered and examined vividly. An assessment of present and future scenarios of FCs based power source topologies and multi‐input DC–DC power converter topologies used in HEV is presented. This survey provides a deep insight into the topic for the researchers and engineers working in this field. [ABSTRACT FROM AUTHOR]

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In this paper, ultrahigh fuel utilization (>98%) in polymer electrolyte fuel cells (PEFCs) is numerically studied to investigate three aspects for this operation strategy: its effect on fuel cell performance, occurance of fuel starvation, and altered water management. Simulation results reveal that the anode flow, when using pure hydrogen fuel, decelerates to nearly zero under the high fuel utlization. The anode gas flow remains high in the hydrogen concentration throughout the gas flow channel, eliminating concerns of fuel starvation and increased anode overpotential. The numerical study confirms the experimental observation that the high-fuel-utilization strategy has very little impact on cell power output in the stable operating regime. It is shown that fuel cell's water removal almost totally relies on the cathode channel flow under ultrahigh fuel utilization, which may be one cause for experimentally observed instability in fuel cell operation under low current density. [ABSTRACT FROM AUTHOR]

Energy demand associated with energy consumption (commonly fossil fuels) has increased in line with the rise in world population and this has led to a number of complications. The best known and most prominent issue induced by fossil fuel utilization is unavoidable greenhouse gas emissions released as a result of the combustion of fuels. Emitted greenhouse gases from various sources, such as industrial plants, power plants, transportation services, residential utilization and so on, are largely responsible for global warming and climate change. According to latest reports, the share of the transportation sector in total energy-related CO2 emissions is approximately 23%. As a result of a detailed investigation and dissemination of transportation-induced emissions, air transportation is found to be responsible for approximately 3–4% of total energy-related CO2 emissions. The current study introduces a different perspective in the evaluation of aircraft greenhouse gas emissions. In this manner, a thermodynamic evaluation on the basis of the first and second laws of thermodynamics and a cost evaluation of greenhouse gases emitted from domestic flights in the UK are presented in the current paper, in addition to an environmental impact assessment. [ABSTRACT FROM AUTHOR]

In the present paper, an extensive energetic and exergetic assessment of a turbojet engine powered by biofuel, hydrogen and JP-8 fuels is performed in view of the thermodynamic principles. According to the results; when the engine fed with the biofuel, the fuel mass stream incremented from 0.16 to 0.184 kg s−1 compared to the utilization of JP-8 fuel, however, the fuel mass stream decreased from 0.184 to 0.058 kg s−1 compared to the utilization of hydrogen fuel. While the exhaust gaseous mass stream rate increased from 9.21 to 9.234 kg s−1 compared to the utilization of JP-8 fuel, it reduced from 9.234 to 9.108 kg s−1 utilization hydrogen. The produced kinetic energy rate by the turbojet engine which is equal to kinetic exergy rate increased from 1130.62 to 1133.63 kW, it is obtained to be 1118.07 kW for the hydrogen fuel. On the other hand, the energy efficiency of the engine increased from 16.39 to 16.43%, compared to the JP-8 fuel utilization, the specific fuel consumption of the engine rose from 0.035 to 0.040 kg kN−1 s−1, while the exergetic efficiency of the engine decreased from 15.34 to 15.25% compared to the JP-8 fuel usage and increased from 14.36 to 15.25% compared to the hydrogen utilization case. The engine's environmental effect factor has risen from 5.52 to 5.56 compared to the JP-8 utilization, the exergetic sustainability index of the overall engine increased from 0.168 to 0.180 compared to the hydrogen utilization case. [ABSTRACT FROM AUTHOR]

One viable approach in reducing reliance on fossil fuels is the utilization of value-added chemicals through the conversion of biomass. In recent years, significant attention has been directed toward the production of 2,5-furandicarboxylic acid (FDCA), a potentially useful bio-based building block generated by electrochemically oxidizing lignocellulose-derived 5-hydroxymethylfurfural (HMF). The key challenge is constructing active, inexpensive, and durable electrocatalysts for promoting HMF electrochemical reactions. Here, we present a simple route for fabricating NiFe layered double hydroxide (LDH)-anchored cobalt carbonate hydroxide (CoCH) on nickel foam (NiFe LDH/CoCH/NF) for HMF electrochemical oxidation. The as-developed NiFe LDH/CoCH/NF exhibits excellent electrocatalytic activity and robust stability, achieving 98.6% yield of FDCA and 98.1% high faradaic efficiency, as well as maintaining above 95% FDCA yield over five cycles of HMF conversion. The higher valence states of Ni, Fe, and Co with oxyhydroxide species most likely accounts for the enhanced electrocatalytic activity of NiFe LDH/CoCH/NF. The pleated nanosheet structure of NiFe LDH/CoCH/NF is also responsible for its improved catalytic HMF oxidation activity, which results in enriched active catalysis sites, facile electron transfer, and increased specific surface area. This work offers a practical technique for developing effective electrocatalysts towards HMF conversion. [ABSTRACT FROM AUTHOR]

This paper explores the various contributors to uncertainty on predictions of the antineutrino source term which is used for reactor antineutrino experiments and is proposed as a safeguard mechanism for future reactor installations. The errors introduced during simulation of the reactor burnup cycle from variation in nuclear reaction cross sections, operating power, and other factors are combined with those from experimental and predicted antineutrino yields, resulting from fissions, evaluated, and compared. The most significant contributor to uncertainty on the reactor antineutrino source term when the reactor was modeled in 3D fidelity with assembly-level heterogeneity was found to be the uncertainty on the antineutrino yields. Using the reactor simulation uncertainty data, the dedicated observation of a rigorously modeled small, fast reactor by a few-ton near-field detector was estimated to offer reduction of uncertainty on antineutrino yields in the 3.0-6.5MeV range to a few percent for the primary power-producing fuel isotopes, even with zero prior knowledge of the yields. [ABSTRACT FROM AUTHOR]

The concerns about climate change, energy security and price fluctuation of fossil fuels are driving the growing interest in the development and utilization of renewable energy as a transportation fuel. In this aspect, the utilization of organic household waste for the production of biogas avoids the environmental impact of landfills. The further upgrading and utilization of biogas as a vehicle fuel avoids the environmental impact of fossil fuels. This paper presents the life cycle assessment of two utilization pathways of biogas produced from co-digestion of organic household waste, grease trap removal sludge and ley crops grown by local farmers. Specifically, this study assessed and compared the environmental impact of the production and utilization of bio-methane and biogas-based electricity as a vehicle fuel for public transport buses in Västerås, Sweden. The system boundary for biogas production covered seven main steps: cultivation, harvesting and transport of ley crops, collection and transport of waste, pre-treatment and co-digestion of the substrate. The system boundary for bio-methane was further extended to account for the upgrading process and tailpipe emissions from combustion of bio-methane in the buses. In the case of biogas-based electricity, the system boundary was further extended to account for the combustion of biogas in the CHP unit and further utilization of electricity in the electric bus. The evaluation of the production routes showed that the methane losses and high energy consumption for both biogas production and upgrading process dominated the environmental impact of bio-methane production. However, the emissions from the CHP unit were solely responsible for the environmental impact of biogas-based electricity production. The functional unit identified for this study is 1 vehicle km travelled (VKT) of the bio-methane fuelled bus and electric bus. The global warming potential of the electric buses was 0.11 kg CO2-eq/VKT compared to 0.26 kg CO2-eq/VKT for the bio-methane buses. The electric buses could also reduce about half of the acidification and eutrophication impacts associated with the bio-methane fuelled buses. The lower fuel efficiency and high tailpipe emissions decreased the environmental advantages of the bio-methane buses. Eventually, this study ensures the biogas utilization which is environmentally sound and compares favourably with the alternative options. [ABSTRACT FROM AUTHOR]

Microfluidic fuel cell (MFC) is a burgeoning category of micro fuel cell technology based on laminar flow electrolytes. The merits of MFC, such as the absence of membrane electrolyte, flexible reactants selection, and high electrolyte conductivity, have been attracting researchers to explore this frontier area over the past two decades. However, realizing practical applications of MFCs remains a tremendous challenge. Many research works have been done to expedite research progress and obtain results reflecting inner mechanism via computational modeling and simulation, the general procedure of which is introduced in this paper. These studies primarily investigate the effects of various geometrical and operational parameters on diverse cell performance metrics, such as open-circuit voltage, current and power densities, and fuel utilization efficiency. However, contradictory outcomes and conclusions may arise due to disparities in the structural and parametric characteristics among different MFC models. In this regard, this review comprehensively summarizes prior computational modeling studies on MFC technology, with specific emphasis on different cell components including microchannels, inlets and outlets, electrodes, etc., as well as effects of different operational conditions encompassing electrolyte input, cell vibration, gas bubbling, and gravity. In addition, other related studies involving paper-based MFCs, cell stacking, and twin models are also introduced. Lastly, the future research perspective on MFC computational modeling is proposed, including potential structural innovations and modeling methods. This review paper shows the big puzzle of MFC modeling, the missing part of which is worthy of further study in the future. [Display omitted] • A comprehensive review on microfluidic fuel cell modeling is presented. • Governing equations and modeling method for microfluidic fuel cell are introduced. • Studies on different cell configurations and operational conditions are introduced. • Studies on paper-based fuel cell, fuel cell stack and twin model are also presented. • Future research directions for microfluidic fuel cell modeling are proposed finally. [ABSTRACT FROM AUTHOR]

Membrane-less fuel cells are a promising power source for portable applications that enable the solving of membrane-related issues, such as water management and high cost, in conventional fuel cells. Apparently, research on this system uses a single electrolyte. This study focused on enhancing the performance of membrane-less fuel cells by introducing multiple reactants that are dual electrolytes with hydrogen peroxide (H2O2) and oxygen as oxidants in membrane-less direct methanol fuel cells (DMFC). The conditions tested for the system are (a) acidic, (b) alkaline, (c) dual medium with oxygen as an oxidant, and (d) dual medium and dual oxygen and hydrogen peroxide as an oxidant. Additionally, the effect of fuel utilization on different electrolyte and fuel concentrations was also studied. It was found that the fuel utilization decreases dramatically with the increasing of the fuel concentration, but it improved with the increasing of the electrolyte concentration until 2M. The performance of the dual oxidants in dual-electrolyte membrane-less DMFCs was 15.5 mW cm−2 of the power density achieved before optimization. Later, the system was optimized, and the power density increased to 30 mW cm−2. Finally, this work presented the stability of the cell using the suggested parameters from the optimization process. This study indicated that the performance of the membrane-less DMFC increased for dual electrolytes with mixed oxygen and hydrogen peroxide as oxidants compared to a single electrolyte. [ABSTRACT FROM AUTHOR]