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The article presents the results of theoretical studies of the ignition process of a water-coal fuel particle under conditions of high-temperature heating at high pressures of the external environment. The authors have developed a new mathematical model of the water-coal fuel particles ignition under stress (pressure – Pg = 1–200 bar, and temperature Tg = 873–1273 K) heating conditions. The mathematical model differs from the known ones by a detailed description of the physicochemical processes occurring during the induction period of time, as well as the processes of phase transitions under high pressure conditions. Based on the results of numerical simulation of the ignition process, it was found that the pressure of the external environment (Pg) has a significant effect on the characteristics and conditions of ignition of water-coal fuel particles. It was shown that the tign(Pg) dependence is essentially nonmonotonic. The authors have established that when Pg changes in the range from 1 to 30 bar (for oxidizer temperatures (Tg = 873–1273 K), an increase in the ambient pressure leads to a nonmonotonic increase in tign. In this way such a dependence tign(Pg) is due to the joint influence of two significant parameters of the factor space, which significantly affects the dynamics of the thermal treatment of fuel. With an increase in the pressure of the mixture of oxidizer and combustible gases, the saturation temperature (the temperature of intense evaporation of water) increases, at the same time, the heat of the phase transition (QL) decreases and the rate of release of pyrolysis gases into the oxidizing environment decreases. Based on the results of the theoretical studies, it has been shown that for efficient combustion of water-coal fuel under the conditions of the combustion chambers of a GT at oxidizer temperatures Tg≥1073K, the pressure in the combustion chamber of the GT must be at least 50 bar. [ABSTRACT FROM AUTHOR]

Enhanced methods of energy conversion present a viable solution for addressing energy load challenges. This study introduces a vibrating combustion engine designed to enhance energy conversion efficiency by harnessing flexible dynamics and variable asymmetric motion. However, the consideration of its unique dynamic effects has emerged as a pivotal challenge in fuel-air mixing and combustion research. This study introduces a fuel spray and mixing simulation method that facilitates the reciprocal exchange of coupling parameters between the combustion and dynamics models. It iterates the simulation outcomes of motion and combustion to predict mixture formation. Subsequently, the method is employed to explore the impact of injection position on fuel spray and mixture formation. Results show that there is an optimum injection position for the operation frequency, and retarding or advancing leads to slow compression and weak gas motion for fuel spray and mixing, although retarded injection provides high in-cylinder gas pressure and temperature. The early injection generally causes long penetration, small droplet diameter, slight impingement, and fast evaporation, unless it is too early. The results further indicate that when IAP = 6 mm, a more uniform mixture can be attained at the beginning of combustion, leading to a thermal efficiency of up to 42.9% for the engine. [ABSTRACT FROM AUTHOR]

A char cone, whose shape is similar to Bunsen flame and varies with oxidation conditions, was found in steady smoldering of biomass rods. In this short communication, characteristics of this char cone in natural downward smoldering of char rods with different diameters (2 – 7 mm) and ash contents (30–46%) were investigated via measuring propagation velocity and analyzing shape of char cone. Results showed that smoldering propagates steadily in all prepared char rods and the propagation velocity decreases with increasing diameter and ash content of char rods. Height of char cone is proportional to the mass flowrate of carbon, similar to the relationship between flame length and volume flowrate of gas fuel in laminar jet diffusion flame. It implies that oxygen diffusion through ash plays a dominant role in natural smoldering of char rod. This work provides some experimental basis for further investigation on mechanism of steady smoldering. [ABSTRACT FROM AUTHOR]

In this paper, a novel two-stage hydrocarbon fuel heating and delivery system was used to more accurately simulate the state of fuel in the cooling channel of the regenerative cooling engine. Mildly cracked (<10%) experiments of n-dodecane were conducted by using the new heating system and pyrolysis products were sampled and analyzed. The ignition delay time and laminar flame speed of the cracked products were different from those of the surrogate gas fuel. When the temperature is 1100 K, the ignition delay time of the cracked products are ~50% higher than that of surrogate gas fuel. The laminar flame speed of the cracked products is about 30% lower than that of surrogate gas fuel at the equivalence ratio of 1.0. The supersonic combustion experiments of mildly cracked and different equivalence ratios n-dodecane were also employed at Mach number 3.0 of the isolator entrance, with total temperature ~1550 K and total pressure ~1.5 MPa. The static pressure along the axis of combustor was measured, while the velocity and temperature of the airflow at the exit of combustor were also measured by the tunable diode laser absorption spectroscopy (TDLAS). The distributions of airflow velocity, static temperature, and total temperature along the combustor at different conditions were analyzed through a one-dimensional analysis method. The deviations of velocity and temperature of the airflow are less than 4% and −6%, respectively, which indicates the calculation is in great accordance with the TDLAS detections. The experimental data will be helpful for validating the simulation of supersonic combustion, and studying the influence of mildly cracked fuel on supersonic combustion characteristics. [ABSTRACT FROM AUTHOR]

In today's industry, H2 is mostly produced from fossil fuels such as natural gas (NG), oil, and coal through various processes. However, all these processes produce both carbon dioxide (CO2) as well as H2, making them questionable in terms of climate change mitigation efforts. In addition to efforts to increase the conversion efficiency of green H2 technologies, work is also underway to make H2 production from fossil fuels more environmentally friendly by reducing/avoiding CO2 emissions. In this framework, these technologies are combined with geologic carbon storage. In a further step, the use of depleted hydrocarbon reservoirs for in situ H2 production is being investigated, with the co-generated CO2 remaining permanently in the reservoir. The objective of this paper is to provide a brief overview of the technologies that can be used to produce H2 from depleted and depleting hydrocarbon reservoirs (DHRs) in various ways. We evaluate the required processes from a reservoir engineering perspective, highlighting their potential for H2 generation and their technology readiness level (TRL) for applications. We also investigate the possibility of permanently storing the co-produced CO2 in the reservoir as a means of mitigating emissions. In addition, we provide a preliminary cost analysis to compare these methods with conventional hydrogen production techniques, as well as an assessment of operational risks and associated cost estimates. [ABSTRACT FROM AUTHOR]

With the work temperature of solid oxide fuel cells (SOFCs) lower to 400–600 °C, the use of CH 4 -based fuel gas needs to be pre-reformed into synthesis gas (H 2 and CO) to mitigate anode carbon deposition. Although lots of catalysts have been widely studied for methane conversion, the development of low temperatures (below 550 °C) catalyst for efficient methane reforming reactions remains a challenge. Here, we proposed a nanosize 5%Rh–5%Pt–5%Al 2 O 3 –85%CeO 2 composite catalyst (RPAC-550), which demonstrates excellent reforming reactions for CH 4 -based mixing fuel gases operating at 550 °C. In this work, the reforming process of RPAC-550 catalyst for dry CH 4 , CH 4 /H 2 O and CH 4 /CO 2 /H 2 O atmospheres in different ratios and operating at 550 °C were systematically studied. Then the obtained reforming gases and carbon deposition were studied thoroughly to get the optimum ratio of mixed fuel gases for SOFCs. At last, the designed RPAC-550 catalyst achieves a CH 4 conversion rate as high as 60% with water-methane ratio in 0.6. Herein, the ratio of H 2 and CO as reforming gases can be controlled precisely by adjusting the intake amount of oxidant CO 2 and H 2 O into CH 4 , which is beneficial for customizing fuel gases. In addition, the RPAC-550 catalyst exhibits remarkable catalytic stability and anti-coking ability under 600 h continue test. This work provides new insights for the rational design of efficient catalysts to reform methane-based fuel gas at 550 °C. • RPAC-550 catalyst exhibits excellent CH 4 reforming performance at 550 °C. • The reforming process for different fuel ratios were systematically studied. • The ratio of reforming gas H 2 and CO was controlled by RPAC-550 catalyst. • RPAC-550 catalyst exhibits 600 h stability. [ABSTRACT FROM AUTHOR]

Ammonia (NH 3), hydrogen (H 2) and methane (CH 4) as zero- or low-carbon fuels are considered as highly promising alternative fuels. Turbulent non-premixed jet combustion is a prospective way in practical combustion devices for ammonia, hydrogen and methane, but the relevant experimental researches are rare, while such information is critical for the development and validation of numerical models. In this paper, the laser diagnostic studies are carried out in a constant volume combustion chamber to investigate the characteristics of the 50%NH 3 +50%H 2 blend jet with or without ignition in comparison to H 2 , CH 4 and NH 3 jets. Firstly, the morphological developments and concentration distributions of the four gas jets without ignition are compared. Then, the OH or NO distributions in the non-premixed gas jet flames are clarified by the planar laser-induced fluorescence techniques. The generation and consumption processes of OH and NO are elucidated by the one-dimensional simulation. The results show that the four jets exhibit a similar morphological development with the nearly same jet angles, except for a little slower tip penetration of 50%NH 3 +50%H 2 blend. The equivalence ratio of the 50%NH 3 +50%H 2 blend and NH 3 jets along the jet axis are lower than those in the CH 4 and H 2 jets due to the difference in the flow rate and stoichiometric number. The H 2 jet exhibits the highest combustion intensity, featuring faster flame propagation, the shortest lift-off length and an apparently higher OH radical intensity, while the NH 3 jet fails to develop a stable flame. The mixture in the 50%NH 3 +50%H 2 blend jet is too lean, resulting in a weaker combustion intensity than the H 2 and CH 4 jets. However, the NO intensity in the 50%NH 3 +50%H 2 jet flame is remarkably stronger than those of the H 2 and CH 4 jet, due to the much higher amount of fuel-type NO converted from NH 3 than that of thermal NO. A self-reducing (SR) zone can be observed where OH is produced and then consumed in the 50%NH 3 +50%H 2 blend, H 2 and CH 4 jet flames. However, the NO SR zone is only observable in the 50%NH 3 +50%H 2 blend jet flames, probably owing to the consumption by the NH 2 and NH radicals. • The laser diagnostic was used to obtained the OH and NO distributions. • The 50%NH 3 +50%H 2 , H 2 , CH 4 and NH 3 jets exhibit a similar morphologic development. • The equivalence ratios of the 50%NH 3 +50%H 2 blend and NH 3 jets are the lowest. • The fuel-type NO makes the strongest NO intensity in 50%NH 3 +50%H 2 blend flames. • For the first time a self-reducing zone was observed for the OH and NO. [ABSTRACT FROM AUTHOR]

Thermal power stations are the largest fossil-fuel-based power-generating station in the country. Hydro and thermal generation combines natural gas as a fossil fuel to generate electricity. Polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyl (PCBs), were determined in the used electrical transformer oil, condensate and power station effluent, including the soil obtained from the condensate and electrical transformer dump site. The results revealed that PAHs had 1.119, 6.483, 0.350, 4.695, 3.314 and 0.732 (mg/g/L), respectively. PCBs 0.052, 0.431, 1.576, 0.013 0.080 and 0.556 (μ/g/L), respectively, in all the analysed samples. The power station effluent had the highest concentration of PCBs with few congeners not detected. The result suggests a risk for the community that uses river water which receives effluent from the thermal station for various domestic applications and the contamination of farm lands for various agricultural purposes. [ABSTRACT FROM AUTHOR]

Anode reforming layer is one of the common strategies to reduce the impact of natural gases as fuel for solid oxide fuel cells (SOFC). This anode reforming layer helps to convert natural gas, for example, methane to hydrogen during the operation of SOFC. Thus, it reduces the formation of carbon deposition and increases the SOFC performance. However, the performance of the anode reforming layer depends on its microstructure characteristic, which may vary based on the synthesis method. Synthesis methods, such as powder, infiltration, coating, and combination routes, are studied to produce an optimum catalyst material. Powder routes, which consist of dry and wet methods, are gaining popularity due to their performance, simple and low-cost method. However, the wet chemical method is favoured for its cost-effectiveness, simplicity, and ability to produce high-quality powder. Thus, this review discussed the wet chemical methods, specifically the sol-gel, co-precipitation and combustion synthesis methods. In addition, the common parameters, previous findings and modifications of these methods were also briefly discussed. This review aims to discuss the various anode reforming layer synthesis methods, a general comparison of the methods and their influence on the properties and performance of SOFCs. [ABSTRACT FROM AUTHOR]

The purpose of this study is to find out and analyze legal accountability and factors that affect perpetrators in the misuse of Pertalite Assignment Fuel Oil. In a five-year period, from 2019 to 2023, the Bali Regional Police Directorate handled 10 cases of misuse of Oil and Gas Fuel. The authors conclude that the absence of regulation regarding the maximum limit for the purchase of special assignment fuel with jerry cans, thus causing the Blurring of Legal Norms, so that this can cause the abuse of fuel oil. Factors such as low legal awareness and public compliance with the rules, the dominance of individual and group interests, and the lack of knowledge about applicable regulations are the main causes of the misuse. [ABSTRACT FROM AUTHOR]

This study investigates the crucial role of Carbon Capture and Storage (CCS) technology in mitigating CO2 emissions from Poland's power systems, which is essential not only for meeting climate targets but also for maintaining energy security in the country. Acknowledging natural gas as a transitional fuel, the focus is on evaluating the decarbonization potential of the natural gas combined cycle (NGCC) power plant. The NGCC with and without an amine-based carbon capture unit was modeled using IPSEpro (SimTech, version 7.0). It was found that the annual CO2 emission from 435.68 MWe (net) NGCC can be reduced from 1,365,501 tons (357.8 kgCO2/MWh) to 136,556 tons (42.9 kgCO2/MWh). On the other hand, the CCS reduced the net electric power of the NGCC from 435.68 MW to 363.47 MW and the net energy efficiency from 55.60% to 46.39%. Nonetheless, these results demonstrate the potential of using the amine-based CO2 capture technology in NGCC systems. This is especially important in the context of the decarbonization of the Polish power system. [ABSTRACT FROM AUTHOR]

Chemical looping combustion (CLC) has been validated as one of the most promising technologies for fossil fuel combustion, which can produce high-purity CO2 streams ready for capture and sequestration in power production. The selection of an appropriate oxygen carrier is one of the most important issues for the CLC process, and the reduction kinetics investigation of the oxygen carrier with fuel gas can provide the basis for CLC reactor design and simulation optimization. In this study, copper ore was chosen as an oxygen carrier, and the oxygen release property of copper ore under a nitrogen environment at various temperatures (1073–1193 K) was first investigated in a thermogravimetric analyzer (TGA). Subsequently, the reduction kinetics of copper ore with CO and H2 were evaluated by the TGA at temperatures ranging from 773 K to 1073 K, using a continuous stream of 5, 10, 15, 20, 25, and 30 vol. % of CO or H2 balanced by CO2 or N2. It was found that the reaction rates of these reactions accelerated with the increase in temperature and fuel gas concentration in inlet gas. Both the oxygen release process of copper ore and the reduction process of copper ore with reducing gases can be described by the unreacted shrinking core model (USCM). The reaction mechanism function for the oxygen-releasing and reduction process of copper ore oxygen carrier was varied. The activation energy of the oxygen-releasing process, reduction process with CO, and reduction process with H2 were calculated as 99.35, 5.08, and 4.28 kJ/mol, respectively. The pre-exponential factor ranged from 1.96 × 10−1 to 1.84 × 103. The reaction order depended on the fuel gas, which was 1 and 0.86, respectively, for reaction with CO and H2. [ABSTRACT FROM AUTHOR]

This article presents the results of an experimental study evaluating the performance of a molten carbonate fuel cell (MCFC) using dairy biogas as a fuel source. Dairy biogas, a renewable byproduct of dairy farming, was compared with hydrogen in terms of operational efficiency. The investigation focuses on the performance parameters and efficiency metrics of MCFCs when powered by dairy biogas, relative to natural gas and hydrogen. The results demonstrate that while dairy biogas can power MCFCs, its efficiency and fuel utilization rates are lower than those of conventional fuels. This study contributes to an understanding of alternative, sustainable fuel sources for MCFC operations. During the study, the performance parameters of dairy biogas were compared with hydrogen, which served as a benchmark fuel. It was observed that in comparison with natural gas, commonly used as a fuel, dairy biogas showed lower efficiency rates and reduced fuel‐utilization factors. This suggests that although dairy biogas can be used as a fuel source for MCFCs, its effectiveness might not be on par with traditional fuels like natural gas. [ABSTRACT FROM AUTHOR]

This study investigates the co‐combustion of palm oil biodiesel fuel, as a renewable alternative for diesel fuel, inside natural gas flame to enhance the flame thermal specifications and NOx reduction. A power natural gas burner with a maximum heat capacity of 418,400 kJ/h was installed at the inlet of a laboratory furnace and biodiesel fuel was injected inside natural gas burner with a 100 μm in diameter solid cone nozzle. Flame temperature, thermal radiation, Infrared radiation, and CO, CO2 and NOx emission were measured. The results revealed that biodiesel injection increases the flame size and turns the non‐luminous blue flame into yellow‐colored flame. Furthermore, higher flash point and Sauter Mean Diameter of biodiesel promote the thermal decomposition of fuel droplets and increase the concentrations of Intermediate Soot Particles in the flame which in turn increases the flame emissivity coefficient and consequently flame thermal radiation. Also, the oxygen content of biodiesel fuel has an important role in the complete combustion of Intermediate Soot Particles to CO2 which increases the heat release of biodiesel combustion and raises the flame temperature. The average enhancement in thermal radiation and flame temperature were 5.6% and 43.38%, respectively. Finally, although biodiesel injection increases the flame temperature, it also increases the flame surface reaction and eliminates the hot spot region in the flame. Therefore, the rate of heat generation per unit volume of flame decreases and this decreases the rate of NOx emission as much as 10.84%. [ABSTRACT FROM AUTHOR]

Realizing the use of biogas as fuel or a gas engine, it is needed to upgrade to natural gas standards when it comes to pure biomethane, meaning impurities must be removed to a certain low concentration. Among these tasks, hydrogen sulfide (H2S) removal steadfastly gets the most attention. In the present work, partial catalytic oxidation was used to convert H2S to less harmful forms. Adsorbents/catalysts applied to this process were prepared from the sludge of a groundwater treatment plant using a simple combination of drying and calcination methods. As a relevant result, the as‐prepared sample (dried at 105°C for 24 h) exhibited high activity, with 90 ± 2% H2S conversion after 120 min of reaction time, while the sample calcined at about 500°C for 5 h (TP‐500) showed the highest H2S conversion (96 ± 2%); the lowest 28 ± 1% belonged to the case of TP‐700. The main compositions of the TP‐500 sample were crystalline calcite and amorphous iron oxides. The average size of calcite crystallites was ~45 nm, with a specific surface area of ~76 m2/g. Moreover, the presence of oxygen in the catalytic process and the "self‐outflow process" of sulfur desorption were the vital keys that allowed the partial H2S oxidation to take place continuously. After a reaction time of 2 h, the adsorption capacity of the best sample was 460.8 mg/g. Thus, it is obvious that inexpensive catalysts derived from sludge precursors can be effectively used for H2S removal from mixtures with air, supporting the treatment of raw biogas in the coming time. [ABSTRACT FROM AUTHOR]

The control strategy of the gas supply subsystem is very important to ensure the performance and stability of the fuel cell system. However, due to the inherent nonlinear characteristics of the fuel cell gas supply subsystem, the traditional control strategy is mainly based on proportional integral (PI) control, which has the disadvantages of large limitation, large error, limited immunity, and inconsistent control performance, which seriously affects its effectiveness. In order to overcome these challenges, this paper proposes an optimal control method for air supply subsystems based on nonlinear active disturbance rejection control (ADRC). Firstly, a seven-order fuel cell system model is established, and then, the nonlinear ADRC and traditional PI control strategies are compared and analyzed. Finally, the two strategies are simulated and compared. The validation results indicate that the integral absolute error (IAE) measure of PI control is 0.502, the integral square error (ISE) measure is 0.1382, and the total variation (TV) measure is 399.1248. Compared with the PI control, the IAE and ISE indexes of ADRC were reduced by 61.31% and 58.03%, respectively. ADRC is superior to PI control strategy in all aspects and realizes the efficient adjustment of the system under different working conditions. ADRC is more suitable for the nonlinear characteristics of the gas supply system and is more suitable for the oxygen excess ratio (OER). [ABSTRACT FROM AUTHOR]

Coastal erosion mobilizes large quantities of organic matter (OM) to the Arctic Ocean where it may fuel greenhouse gas emissions and marine production. While the biodegradability of permafrost‐derived dissolved organic carbon (DOC) has been extensively studied in inland soils and freshwaters, few studies have examined dissolved OM (DOM) leached from eroding coastal permafrost in seawater. To address this knowledge gap, we sampled three horizons from bluff exposures near Drew Point, Alaska: seasonally thawed active layer soils, permafrost containing Holocene terrestrial and/or lacustrine OM, and permafrost containing late‐Pleistocene marine‐derived OM. Samples were leached in seawater to compare DOC yields, DOM composition (chromophoric DOM, Fourier transform ion cyclotron resonance mass spectrometry), and biodegradable DOC (BDOC). Holocene terrestrial permafrost leached the most DOC compared to active layer soils and Pleistocene marine permafrost. However, DOC from Pleistocene marine permafrost was the most biodegradable (33 ± 6% over 90 days), followed by DOC from active layer soils (23 ± 5%) and Holocene terrestrial permafrost (14 ± 3%). Permafrost leachates contained relatively more aliphatic and peptide‐like formulae, whereas active layer leachates contained relatively more aromatic formulae. BDOC was positively correlated with nitrogen‐containing and aliphatic formulae, and negatively correlated with polyphenolic and condensed aromatic formulae. Using estimates of eroding OM, we scale our results to estimate DOC and BDOC inputs to the Alaska Beaufort Sea. While DOC inputs from coastal erosion are relatively small compared to rivers, our results suggest that erosion may be an important source of BDOC to the Beaufort Sea when river inputs are low. Plain Language Summary: Arctic coastlines are rapidly eroding into the ocean. Soils along these coastlines contain large quantities of organic matter (OM) that dissolves in seawater and may be consumed by microbes. If this dissolved organic matter (DOM) is biodegradable, it can be an important energy source to coastal food webs and/or quickly decomposed to greenhouse gases. We used laboratory experiments to examine the chemical composition of the DOM that is released from eroding soils into seawater and measured its biodegradability. We compared results for three different layers of soil at Drew Point, Alaska, including near‐surface soils that thaw seasonally and deeper soils that are perennially frozen (permafrost). Our results show that different layers, which contain OM of different sources and ages, have distinct chemical characteristics that impact biodegradability. While rivers supply more OM to the Alaska Beaufort Sea than coastal erosion, our results show that DOM released from all soil layers is highly biodegradable, and that DOM from deep permafrost is the most biodegradable. We deomonstrate that coastal erosion can be an important source of OM to Arctic coastal ecosystems, particularly in locations and seasons (e.g., late summer) that receive fewer river inputs. Key Points: Eroding soils and permafrost along the Alaska Beaufort Sea coast leach biodegradable dissolved organic carbon into seawaterBiodegradability was higher in leachates from Late‐Pleistocene relict marine permafrost than Holocene terrestrial soils and permafrostPermafrost leached aliphatic and peptide‐like molecular formulae that were not present or less abundant in active layer soils [ABSTRACT FROM AUTHOR]

The unprecedented increase of atmospheric CO2 concentration and the associated climate change calls for the urgent implementation of CO2 mitigation approaches. Among the various proposed measures, CO2 capture from several industrial point sources or directly from air and its subsequent hydrogenation via renewable H2 towards value-added products formation has gained particular attention. Specifically, the production of CO or CH4 is of great importance for the eventual generation of liquid fuels or synthetic natural gas, respectively. Herein, an overview of the state-of-the-art noble and non-noble metal-based catalysts employed for the thermocatalytic CO2 hydrogenation towards CO (reverse water–gas shift reaction, rWGS) or CH4 (Sabatier reaction) is elaborated. A brief description of fundamental considerations is initially provided for each reaction, involving thermodynamic, mechanistic and kinetics considerations. Then, the recent catalytic studies on rWGS and Sabatier reactions over both noble metal and non-noble metal catalysts (e.g., metal oxides, carbides, metal organic frameworks) are discussed from the perspective of structure–property relationships. Lastly, the most important conclusions arising from the comparative analysis of the most promising catalysts are summarized and are complemented with proposed outlooks associated with future directions towards the rational design of highly active and selective catalytic materials for each process. Highlights: Recent advances on the catalytic CO2 hydrogenation to CO or CH4 Comprehensive overview and comparison of state-of-the-art catalytic systems Thermodynamic, mechanistic and kinetics considerations Rational design of cost-efficient and highly active CO2 hydrogenation catalysts [ABSTRACT FROM AUTHOR]

By increasing solar radiation, the temperature of photovoltaic cells rises, and as a result, the electrical power and lifespan of the panel are reduced. By cooling the panel with two-phase closed thermosyphons (TPCTs), this effect can be minimized. In contrast to typical TPCT, which has a circular cross-section, the thermosyphon used in this study has a square cross-section. In the proposed system, the solar cells place on an aluminum plate to reduce the thermal resistance and improve the heat transfer rate. Investigations have been made on the effects of three different filling ratios, including 25, 45, and 65%. The trial results show that equipped PV panel with square TPCT with a filling ratio of 45% produces the best cooling performance. In this instance, 68.31 kJ of heat energy was transmitted to the tank water. Electrically, the equipped panel has been found to produce up to 3.85% greater output power than a conventional one. A new mathematical model to estimate the performance of equipped PV panel with square TPCT is introduced too. Additionally, the research has looked into how varied tank volumes, solar radiation, and wind velocity affect the temperature difference in tank water. Based on environmental investigations, the proposed solar system is used instead of natural gas and fuel oil, it will prevent the annual emission of 106.3 and 159.4 kg of CO2 per unit area of the panel to atmosphere. [ABSTRACT FROM AUTHOR]

High-temperature co-electrolysis is studied on electrolyte-supported NiO-YSZ/NiO-SDC/ScSZ/LSCF-GDC/LSCF (NiO: Nickel Oxide, YSZ: Yttria-stabilized zirconia, SDC: Samarium-doped ceria, ScSZ: Scandia-stabilized zirconia, LSCF: Lanthanum Strontium Cobalt Ferrite, GDC: Gadolinium-doped ceria) button cell. Electrochemical impedance spectroscopy (EIS) was recorded under open-circuit voltage (OCV) and co-electrolysis mode over various operating conditions, including temperature, water vapor content, and applied voltage. Interfacial polarization resistance (Rp) is obtained from peak arcs located in the three regions: gas conversion resistance (Region I (0.01 to 0.1 Hz)), gas diffusion resistance (Region II (0.1 to 100 Hz)) and air electrode charge transfer resistance (Region III (100 to 10,000 Hz)). As the temperature increased from 700 to 850 oC, Rp decreased from 18.15 to 3.32 Ω.cm2 at 1.3 V for 10%CO2/3%H2O. From the Distribution of relaxation times (DRT) studies, one additional peak, P5 (fuel gas conversion or gas-phase diffusion in the pores of the air electrode), is observed, and Region III (100 to 10,000 Hz) consists of two additional peaks: P1 (ionic transport coupled with gas diffusion close to triple phase boundaries (TPBs)) and P2 (fuel electrode charge transfer reaction), which were not clearly distinguished from EIS. Region II dominates in the overall polarization resistance. At 800 oC, for 10%CO2/3%H2O, the Rp decreased from 6.78 to 4.82 Ω.cm2, with an increase in the applied voltage from 1.3 to 1.5 V. At 800oC/1.5 V, the Rp values are 4.41, 8.09, and 6.77 Ω.cm2 for H2O, CO2, and co-electrolysis. At 800 ºC/1.5 V, with an increase in the water vapor content from 3%H2O to 15%H2O, there is not much change in the Rp value; therefore, 10%H2O is sufficient. H2 consumption is between 23 and 36%, depending on the temperature at OCV. At 800 °C for (10%H2/10%CO2/10%H2O), co-electrolysis occurs at applied voltage, along with Reverse water gas shift (RWGS) reaction. [ABSTRACT FROM AUTHOR]

Solid oxide fuel cell power generation systems are devices that utilize solid electrolytes to transfer ions for electrochemical energy conversion. A wide range of gases can be used as fuel gas, including hydrogen, natural gas, and carbon monoxide. Considering the high cost of pure hydrogen, hydrogen production from natural gas reforming has become a hot research area. In this study, the 4F-LCA method was employed to construct an evaluation framework, with a particular emphasis on the cost analysis of solid oxide fuel cell power generation systems, and uses a bottom-up approach to build a system economic analysis model to visualize the major costs involved in the system. An economic benefit analysis and sensitivity analysis were carried out for the 2 kW natural gas solid oxide fuel cell as a case by taking the financial net present value (NPV), internal rate of return (IRR) and payback period into account. In this study, the investment cost and payback period of a 2 kW solid oxide fuel cell system are obtained, which can provide a reference for the project construction and operation of solid oxide fuel cell systems. [ABSTRACT FROM AUTHOR]

Currently, the process of creating industrial installations is associated with digital technologies and must involve the stage of developing digital models. It is also necessary to combine installations with different properties, functions, and operational principles into a single system. Some tasks require the use of predictive modeling and the creation of "digital twins". The main processes during the fuel cell modeling involve electrochemical transformations as well as the movement of heat and mass flows, including monitoring and control processes. Numerical methods are utilized in addressing various challenges related to fuel cells, such as electrochemical modeling, collector design, performance evaluation, electrode microstructure impact, thermal stress analysis, and the innovation of structural components and materials. A digital model of the membrane-electrode unit for a solid oxide fuel cell (SOFC) is presented in the article, incorporating factors like fluid dynamics, mass transfer, and electrochemical and thermal effects within the cell structure. The mathematical model encompasses equations for momentum, mass, mode, heat and charge transfer, and electrochemical and reforming reactions. Experimental data validates the model, with a computational mesh of 55 million cells ensuring numerical stability and simulation capability. Detailed insights on chemical flow distribution, temperature, current density, and more are unveiled. Through a numerical model, the influence of various fuel types on SOFC efficiency was explored, highlighting the promising performance of petrochemical production waste as a high-efficiency, low-reagent consumption fuel with a superior fuel utilization factor. The recommended voltage range is 0.6–0.7 V, with operating temperatures of 900–1300 K to reduce temperature stresses on the cell when using synthesis gas from petrochemical waste. The molar ratio of supplied air to fuel is 6.74 when operating on synthesis gas. With these parameters, the utilization rate of methane is 0.36, carbon monoxide CO is 0.4, and hydrogen is 0.43, respectively. The molar ratio of water to synthesis gas is 2.0. These results provide an opportunity to achieve electrical efficiency of the fuel cell of 49.8% and a thermal power of 54.6 W when using synthesis gas as fuel. It was demonstrated that a high-temperature fuel cell can provide consumers with heat and electricity using fuel from waste from petrochemical production. [ABSTRACT FROM AUTHOR]

This paper investigates how gendered spaces are configured within local socio-cultural systems of beliefs and in what way energy interacts with cultural constructions in an Indigenous village of the Brazilian Amazon. Particularly, this paper explores the perceived changes brought by fuel availability and affordability on gendered division of space and local cosmologies. Ethnographic techniques were adopted in the collection of primary data, particularly participant observation and in-depth interviews were best suited to understand the lived experiences of these changes. This paper found that access to cooking gas and fuel for transportation can partially shift pre-existing gendered spaces and, in turn, gendered practices. However, this shift does not challenge pre-existing hierarchies of power which still limit women's freedom of movement. [ABSTRACT FROM AUTHOR]

This paper presents an analysis of the acceleration of a fast boat using a simulation model. Mathematical equations of ship motion dynamics with two types of propeller capabilities are developed using MATLAB and Simulink as simulation tools. The equations are extended to include the acting thrust, resistance, propeller's performance curves, and the PID governor curve for the acceleration manoeuvre. The application models the dynamic differential equations representing the vessel dynamics in one degree of freedom. MATLAB code was used to develop the ship acceleration as a multibody system. Modules of hydrodynamic forces, resistance, moments, and propeller performances were implemented to simulate the ship manoeuvring process. A comparison of the results for the boat's propulsion performance with two different propellers and the characteristics of the PID governor, which controls the fuel dose in the gas turbines, was carried out. We present a summary including a comparative analysis of the results for the boat dynamics with and without the PID governor. The results obtained here confirm significant discrepancies between the results of numerical simulations with and without the PID governor. [ABSTRACT FROM AUTHOR]

Ammonia–methane (NH3–CH4) mixtures have potentials to serve as low-carbon fuels for gas turbines. Recent studies demonstrated that secondary air injection was an effective strategy to reduce NOx emissions from the combustion of NH3–CH4–air mixtures. However, the effects of secondary air injection on the performance of thermoacoustic instability of NH3–CH4–air flames remain unknown. To this end, this study experimentally investigated the thermoacoustic instability performance of a premixed, swirl-stabilized NH3–CH4–FF air combustor without and with secondary air injection. Without secondary air injection, thermoacoustic instabilities were widely detected at NH3 ratios below 50% (by volume). It was discovered that such instabilities were significantly suppressed by secondary air injection over a wider range of operating conditions. In conjunction with the analysis of the flame and flow dynamics, it was revealed that the secondary air injection suppressed the large amplitude axial oscillations of the flame and the flow field. Combined with the experimental results, it was inferred that the introduction of secondary air changed the velocity and pressure distribution downstream of the primary combustion zone, which in turn affected the formation and evolution of the vortex structures, thereby mitigating thermoacoustic coupling. Finally, emission measurements were discussed and the results indicated that the secondary air injection strategy reduced unburnt NH3 and CO emissions to a certain extent as well as decreased NOx emissions at specific equivalence ratios. [ABSTRACT FROM AUTHOR]

There is growing consensus that gas-fired generators will play a crucial role during the transition to net-zero energy systems, both as an alternative to coal-fired generators and as a flexibility service provider for power systems. However, malfunctions of gas networks have caused several large-scale power blackouts. The transition from coal and oil to gas fuels significantly increases the interdependence between gas networks and electric power systems, raising the risks of more frequent and widespread power blackouts due to the malfunction of gas networks. In a coupled gas–electricity system, the identification and transmission of gas network malfunction information, followed by the redispatch of electric power generation, occur notably faster than the propagation and escalation of the malfunction itself, e.g., significantly diminished pressure. On this basis, we propose a gas-electric early warning system that can reduce the negative impacts of gas network malfunctions on the power system. A proactive control strategy of the power system is also formulated based on the early warning indicators. The effectiveness of this method is demonstrated via case studies of a real coupled gas–electricity system in China. Gas-fired generators play crucial role in the transition to net-zero energy systems as an alternative to coal-fired. But malfunctions of gas networks can cause large-scale power blackouts. Here, authors apply the early warning concept to the coupled gas-electric system towards enhanced power supply security. [ABSTRACT FROM AUTHOR]

Fuel gas desulfurization is an important technological step toward achieving environmental neutrality in industrial production. The presence of sulfur compounds in fuel not only significantly increases the rate of corrosion processes, but also increases the amount of sulfur oxides in flue gases. Adsorption technologies are actively used to purify fuel. Materials that are mainly chosen as sorbents are determined by economic feasibility. These materials include bentonite clays. The paper presents an analysis of scientific works on the possible methods of using bentonite clays in industry. Due to its natural properties, this material has high adsorption properties. The authors present experimental laboratory studies to determine the adsorption efficiency of bentonite clay with a carbon substrate. Results on the adsorption capacity after regeneration of the composition are also presented. Based on the data obtained, the adsorption unit was calculated, and the process flow diagram was designed. [ABSTRACT FROM AUTHOR]

Hydrogen, stored as a liquid at cryogenic temperatures to enhance transport efficiency, is susceptible to boiling due to thermal fluctuations, underscoring the importance of investigating thermal insulation for liquid hydrogen piping. Evaluating their suitability and effectiveness for hydrogen ship piping remains critical. This study conducted numerical simulations to analyze insulation and phase-change impacts on the multiphase thermal flow of piping systems used for the Fuel Gas Supply System (FGSS) of hydrogen-fueled ships. The accuracy of the adopted phase-change model was validated against selected experimental cases of boiling phenomena, demonstrating agreement with experimental results. We applied the validated phase-change model to simulate multiphase thermal flow in an LH2 pipe and evaluated the thermal performance of insulation materials. The insulation material considered in this study is a composite insulation system with various filling materials. Specifically, we observed that the insulation performance was superior when utilizing a combination of vacuum insulation along with MLI Mylar nets. Additionally, we evaluated the safety within the pipe by comparing the amount of vapor generated inside with the Lower Flammability Limit (LFL). Our results indicate that a safety assessment of the insulation is necessary when no filling material is used. Quantitatively, we found that pipes with composite vacuum and MLI Mylar net insulation reduced vapor generation by 45% compared to vacuum-only insulation, highlighting the effectiveness of the proposed insulation method. [ABSTRACT FROM AUTHOR]

This study aims to analyze the thermodynamic considerations for the application of liquefied natural gas (LNG) as a transportation fuel. It is designed to solve transport fuel problems and tackle public health issues associated with vehicular engine emission, and vehicle fuel shortages. It considers the economic and technical viability of applying low-temperature fluid as fuel in an LNG-fuel Spark Ignition Engine through computer simulation. Process design configuration was achieved using the User Define Function (UDF) in fluid simulation software (ANSYS Fluent), Finite Element Analysis and Aspen Hysys. 12 kg capacity volume cryogenic tank design was done through Autodesk inventor with an initial temperature of -1620C and pressure of 1 bar and ambient temperature application ranges of 200C to 400C. The ANSYS simulation result showed a thermodynamic effect of heat and mass transfer rate range of 1.6% to 7% W/m²k concerning the time taken by the tank to absorb heat through temperature ranges of -1550C to 2500C. Also, 0.04kg/s was the total volume of boil-off gas (BOG) produced, while the maximum exhaust gas emissions recorded was 0.254kg/s. The advantage of this technology was the minimal volume of greenhouse gases released during combustion relative to gasoline and diesel, signifying less pollution, and buttressing the applicability and adoption of LNGFuel as a transport fuel. [ABSTRACT FROM AUTHOR]

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The current trends converge towards minimizing the carbon footprint on the environment in the operation of all thermal equipment and need finding alternative solutions compared to what the market offers at the moment. Utilizing hydrogen in combustible mixtures with methane gas to fuel condensing boilers is one solution. The benefit is that it reduces carbon dioxide emissions into the atmosphere as only water vapor is produced when hydrogen undergoes combustion. The effects of adding hydrogen at percentages of 23%, 30%, 35% and 45%, respectively, to the combustible gas mixture are examined in the paper. [ABSTRACT FROM AUTHOR]

Detonation engines are gaining prominence as next-generation propulsion systems that can significantly enhance the efficiency of existing engines. This study focuses on developing an injector utilizing liquid fuel and a gas oxidizer for application in detonation engines. In order to better understand the spray characteristics suitable for the pulse detonation engine (PDE) system, an injector was fabricated by varying the Venturi nozzle exit diameter ratio and the geometric features of the fuel injection hole. Analysis of high-speed camera images revealed that the Venturi nozzle exit diameter ratio plays a crucial role in determining the characteristics of air-assist or air-blast atomization. Under the conditions of an exit diameter ratio of Re/Ri = 1.0, the formation of a liquid film at the exit was observed, and it was identified that the film's length is influenced by the geometric characteristics of the fuel injection hole. The effect of the fuel injection hole and Venturi nozzle exit diameter ratio on SMD was analyzed by using droplet diameter measurement. The derived empirical correlation indicates that the atomization mechanism varies depending on the Venturi nozzle exit diameter ratio, and it also affects the distribution of SMD. The characteristics of the proposed injector, its influence on SMD, and its velocity, provide essential groundwork and data for the design of detonation engines employing liquid fuel. [ABSTRACT FROM AUTHOR]

The rising amount of greenhouse gases has been contributing to global warming and, subsequently, climate change. Industries such as refineries and power plants emit a significant amount of CO2 into the atmosphere. It is imperative to curb anthropogenic CO2 emissions, and hence, in this effort, we explore the utilization of a refinery emission stream to produce value‐added chemicals. The chosen emission stream for the said purpose is a typical flue gas stream from refineries. Following the capture step, this CO2 stream has been leveraged for subsequent valorization processes. Two strategies have been proposed in this paper to valorize the captured carbon dioxide. The first strategy employs the tri‐reforming process with a refinery‐specific fuel gas stream as the co‐reactant. The resulting syngas from tri‐reforming has been converted to chemicals such as methanol (MET) and ethanol. Furthermore, to improve the amount of CO2 valorized, another approach with green hydrogen has been considered. The second strategy aims at direct hydrogenation of the captured CO2 stream to produce MET and ethanol. The proposed strategies analyze the feasibility of valorizing captured CO2 from flue gas to MET and ethanol in terms of gross margin per feed and percentage of CO2 valorization. The performance assessment and analysis of the proposed processes have been carried out using simulations in Aspen Plus® that exhibited up to 74% valorization of CO2 into valuable chemicals. [ABSTRACT FROM AUTHOR]

In this paper, a diabatic compressed air energy storage system fueled by a natural gas/hydrogen mixture that integrates heating and power generation is proposed. A comprehensive thermodynamic analysis has been conducted to identify the key factors influencing system performance and elucidate the detailed formation and distribution patterns of irreversible losses when utilizing a hydrogen-natural gas blend as fuel in the proposed system. The research results indicate that increasing the hydrogen blending ratio from 0.5 to 1 lead to greater enhancements in roundtrip efficiency (∼1.08% vs. ∼0.33%), exergy efficiency (∼3.88% vs. ∼1.15%), and energy density (∼1.24% vs. ∼0.42%) compared to an increase from 0 to 0.5. The combustor suffers the largest exergy destruction proportion, with a notable reduction in exergy destruction achieved through increased hydrogen blending. System performance benefits significantly from higher combustor outlet temperatures and expansion ratios at various hydrogen blending ratios. The rate of change in exergy efficiency (∼42.76% vs. ∼83.17%) and energy density (∼58.83%) demonstrates an inverse correlation with the varied parameters (1100–1500K, 4–8), except for the rate of change in energy density (∼6.76%), which displays a positive relationship with the combustor outlet temperature. Notably, a significant decrease in the rate of change in roundtrip efficiency (∼1.87% vs. ∼6.64%) is observed within a specific parameter range (1400–1500K, 5–6). Sensitivity analysis identifies the combustor outlet temperature as the most influential factor in enhancing system performance, consistently showing positive effects of the hydrogen blending ratio. [Display omitted] • A natural gas/hydrogen-fueled CAES system combined heating and power is proposed. • Increasing the hydrogen contents significantly reduces combustor exergy destruction. • Higher hydrogen content (>0.5) yields notable performance boosts, especially in EXE. • The ROC s infected by ER display a remarkable correlation compared to the COT. • The COT is the crucial parameter on system performance via sensitivity analysis. [ABSTRACT FROM AUTHOR]

To attain a net zero-carbon emissions energy system, the grid needs dispatchable and flexible power production capable of responding to wind and solar energy variability. Hydrogen-fired gas turbines could play a role in meeting this requirement in the electricity grid; however, research and development are needed to assess the impact of the fuel change on these systems. This study aims to determine the effect of fuel switching on the cycle performance of a typical aero-derivative gas turbine, ranging from 25-35MW when combined with various steam-based bottoming cycles using Aspen Plus thermodynamic simulations. The gas turbine cycle's efficiency and net output power increased by about 2.26% and 5.24%, respectively, when fueled with hydrogen for the constant TIT control strategy compared with the base case. The other two control strategies—constant TOT and heat input—are also positive. The performance of the combined heat and power configurations, expressed by the fuel charged to power, is better for almost all the hydrogen-fired cases compared with the methane case. This implies that using hydrogen as fuel in the gas turbine and duct-firing requires less fuel to produce heat and electricity. Although hydrogen integration into the overall system may pose challenges with auxiliary equipment, storage, supply, and combustion, hydrogen as fuel shows promise in improving the performance of gas turbine combined heat and power units. • Hydrogen for GTs will be an enabler of low-carbon and flexible power production. • Switching to hydrogen enhances power and heat production in all operating strategies. • The GT performance improves with the hydrogen fraction for all operating strategies. • Hydrogen firing increases the operational flexibility of GT-based CHP configurations. [ABSTRACT FROM AUTHOR]

The production of hydrogen-rich gas used in fuel cell-powered cars from steam reforming and sorption-enhanced steam reforming of ethanol was studied over nickel-impregnated mesoporous carbon catalyst in conventional and microwave heated reactor systems. Two important process intensification methods, sorption-enhanced reforming and microwave heating, were investigated to obtain a sustainable and energy-efficient system. Higher hydrogen yield was observed in the microwave heated system compared to the conventional heated system. With an increase in the reaction temperature, the hydrogen yield and hence the hydrogen concentration were increased in both systems. Sorption-enhanced steam reforming resulted in very high hydrogen purity, higher than 97 %, containing no carbon monoxide and carbon dioxide before the breakthrough point in the microwave system at 500 °C. The outperformance of the microwave system compared to the conventional system was proved in terms of the hydrogen yield and purity. • Nickel impregnated mesoporous carbon catalyst has a high microwave absorption capacity in the microwave system. • Higher hydrogen yield and purity were achieved in the microwave system. • Sorption-enhanced results revealed very high H 2 purity in the MW reactor at 500 °C during the first 25 min of the reaction. • The enhancement in hydrogen yield and purity in the MW system are evidence of its superiority to the conventional system. [ABSTRACT FROM AUTHOR]

Public institutions, emblematic of public infrastructure, exhibit extensive reach and operational scope, positioning them as vanguards in China's dual carbon initiatives and serving as exemplars. Electricity and natural gas predominantly fuel the operations of public institutions. Notably, the fixed commute routes and consistent procurement patterns of office personnel yield a standardized energy consumption profile within these entities. Researching carbon emissions related to commuting and evaluating procurement strategies for reducing carbon footprints in public institutions demonstrate a precision-tailored approach. This paper, through an analysis of the energy consumption characteristics, utilization structure of public institutions, and the commuting behaviors and procurement practices of office personnel, establishes a bespoke carbon accounting model specifically designed for public institutions, seamlessly embedded within a comprehensive platform. By providing fundamental methodological frameworks and advanced technological foundations for carbon accounting in public institutions across China, this work propels the nation's efforts towards carbon peak and ultimately carbon neutrality. [ABSTRACT FROM AUTHOR]

In this work, the dynamic marine atmospheric corrosion behavior of AZ91 Mg alloy sailing from Yellow Sea to Western Pacific Ocean was studied. The corrosion rates were measured using the weight loss method. The microstructure, phase, and chemical composition of corroded samples were investigated by SEM, EDS, XRD, and XPS. The results show that the evolution of corrosion rates of AZ91 Mg alloy was divided into three stages: rapidly increasing during the first 3 months, then remaining stable for the next three months, and finally decreasing after 6 months. The annual corrosion rate of Mg alloy reached 32.50 μm/y after exposure for 12 months in a dynamic marine atmospheric environment, which was several times higher than that of the static field exposure tests. AZ91 magnesium alloy was mainly subjected to localized corrosion with more destructiveness to Mg parts, which is mainly due to the synergistic effect of high relative humidity, the high deposition rate of chloride ion, sulfur dioxide acidic gas produced by fuel combustion, and rapid temperature changes caused by the alternating changes in longitude and latitude during navigation. As the exposure time increased, the corrosion pits gradually increased and deepened. The maximum depth of the corrosion pit was 197 μm after 12 months of exposure, which is almost 6 times the average corrosion depth. This study provides scientific data support for the application of magnesium alloys in shipborne aircraft and electronic equipment. The results could provide guidance for the design of new magnesium alloys and development of anti-corrosion technologies. [ABSTRACT FROM AUTHOR]

These days, during the issues of climate change, there has been a shift in the energy industry from using fossil fuels to more environmentally friendly fuels such as biomass fuels. Biomass fuel is considered CO2 neutral because the carbon produced during combustion in the form of CO2 emissions can be used for new plant growth. However, besides the advantages of using biomass fuel, a problem arises when biomass fuel contains a high concentration of corrosive agents, which can be released along with hot fuel gas. These corrosive agents can damage the boiler components. Coating technology is one of the solutions to protect components that work at high temperatures against the corrosion threat. One type of coating that can be used in high-temperature applications is NiCrAlY coating by the high-velocity oxide (HVOF) process. One interesting topic that people are developing is using nano-scale coating to increase the coating’s resistance against hot corrosion and cracking. Nano-scale powder feedstock is needed to produce nano-scale coating material. In this research, top-down method is used to synthesis nano-scale powder. One of top down method, the high-energy ball milling processs, is a promising method to synthesize nano-scale powder material. Therefore, in this research, the ball milling process is used to prepare nano-scale product. The results showed that this method was successful to make the nano-scale powder. The nano-scale powder was characterized by several methods to investigate the morphology and properties of the powders. However, there are still many challenges in producing nano-scale powder that meets HVOF feedstock powder requirements. In the long run, it is expected that this research can answer those challenges so that at the end, the good quality of nano-scale powder can be achieved. [ABSTRACT FROM AUTHOR]

The black hole-and-galaxy (BH-galaxy) co-evolution paradigm predicts a phase where most of the star formation (SF) and BH accretion takes place in gas-rich environments, namely, in what are likely to be very obscured conditions. In the first phase of this growth, some of the galactic gas is funnelled toward the centre of the galaxy and is accreted into the supermassive BH, triggering active galactic nucleus (AGN) activity. The large quantity of gas and dust hides the emission and the AGN appears as an obscured (type 2) AGN. The degree of obscuration in type 2 AGNs may even reach values as high as NH > 1024 cm−2 (i.e., Compton-thick, CT). Population synthesis models of the X-ray background (XRB) suggest that a large population of CT-AGN is, in fact, needed to explain the still unresolved XRB emission at energy above 20 keV. In this work, we investigated the properties of 94 [Ne V]3426 Å-selected type 2 AGN in COSMOS at z = 0.6 − 1.2, performing optical-to-far-infrared (FIR) spectral energy distribution (SED) fitting of COSMOS2020 photometric data to estimate the AGN bolometric luminosity and stellar mass, star formation rate, age of the oldest stars, and molecular gas mass for their host-galaxy. In addition, we performed an X-ray spectral analysis of the 36 X-ray-detected sources to obtain reliable values of the AGN obscuration and intrinsic luminosity, as well as to constrain the AGN properties of the X-ray-undetected sources. We found that more than two-thirds of our sample is composed of very obscured sources (NH > 1023 cm−2), with about 20% of the sources being candidate CT-AGN and half being AGNs in a strong phase of accretion (λEdd > 0.1). We built a mass- and redshift-matched control sample and its comparison with the [Ne V] sample indicates that the latter has a higher fraction of sources within the main sequence of star-forming galaxies and shows little evidence for AGNs quenching the SF. As the two samples have similar amounts of cold gas available to fuel the SF, this difference points towards a higher efficiency in forming stars in the [Ne V]-selected sample. The comparison with the prediction from the in situ co-evolution model suggests that [Ne V] is an effective tool for selecting galaxies in the obscured growth phase of the BH-galaxy co-evolution paradigm. We find that the "quenching phase" is still to come for most of the sample and only few galaxies show evidence of quenched SF activity. [ABSTRACT FROM AUTHOR]

The results of diagnostic tests under steady-state speed conditions of an unloaded engine do not fully reflect the emissivity of vehicles adapted to run on natural gas. Therefore, it is reasonable to pay attention to the emissions performance of these vehicles under dynamic conditions. In this regard, the tests were carried out on a chassis dynamometer with the engine fueled by gasoline and natural gas. Due to the area of operation of natural gas vehicles being usually limited to urban areas, the urban phases of the NEDC (New European Driving Cycle) and WLTC (Worldwide harmonized Light-duty vehicles Test Cycle) were adapted. While CO2 emissions are lower when fueled by natural gas, CH4 emissions can be high, which is related to momentary changes in the composition of the combustible mixture. Although CH4 emissions are higher when the engine runs on natural gas, the CO2eq value is, depending on the driving cycle, about 15–25% lower than when running on petrol. Additionally, studies have shown that in engines adapted to run on CNG (compressed natural gas), it is advisable to consider the use of catalytic converters optimized to run on natural gas, as is the case with vehicles which are factory–adapted to run on CNG. [ABSTRACT FROM AUTHOR]

Technologies used in the transport sector have a substantial impact on air pollution and global warming. Due to the immense impact of air pollution on Earth, it is crucial to investigate novel ways to reduce emissions. One way to reduce pollution from ICE is to use alternative fuels. However, blends of alternative fuels in different proportions are known to improve some emissions' parameters, while others remain unchanged or even worsen. It is therefore necessary to find ways of reducing all the main pollutants. For SI engines, mixtures of hydrogen and natural gas can be used as alternative fuels. The use of such fuel mixtures makes it possible to reduce CO, HC, and CO2 emissions from the engine, but the unique properties of hydrogen tend to increase NOx emissions. One way to address this challenge is to use port water injection (PWI). This paper describes studies carried out under laboratory conditions on an SI engine fuelled with CNG and CNG + H2 mixtures (H2 = 5, 10, 15% by volume) and injected with 60 and 120 mL/min of water into the engine. The tests showed that the additional water injection reduced CO and NOx emissions by about 20% and 4–5 times, respectively. But, the results also show that water injection at the rate of 120 mL/min increases fuel consumption by between 2.5% and 7% in all cases. [ABSTRACT FROM AUTHOR]

Interest group literature suggests reformer advocacy groups, seeking policy change and innovation, are more likely to secure policy victory in local government. Entrenched advocacy groups, favoring current policies, are better suited to win policy battles at the state level. Consequently, entrenched groups have pushed state legislatures to limit local governments' decision authorities through preemption across a wide range of public‐interest issues including tobacco use, gun control, marriage rights, and climate change. Yet few studies have considered how competing advocacy groups strategically frame their agenda in preemption debates. We draw on the "scope of conflict" literature to show that opposing camps vary in their issue definition, relational strategies, and institutional frames. For example, while entrenched advocates focus on the main issue under debate, reformer advocates link multiple issues together. Our study case is preemption legislation that prohibits local governments from banning energy fuels like natural gas in new buildings. We use computational text analysis and descriptive inference to analyze state committee testimony of 117 advocacy groups. Results raise important questions about the effectiveness of conflict expansion strategies in venues like committee systems and provide considerations for reformer advocates in their efforts to secure state support and build clean energy campaigns. [ABSTRACT FROM AUTHOR]

Graded metal pushered single shells (PSS) are a viable alternative to low-Z capsules (Z is the atomic number) for indirect drive inertial confinement fusion implosions due to enhanced core tamping and radiation trapping, but they can be compromised by the pusher mixing with the fuel. We compare 2-shock and 3-shock laser pulses for Be/Cr PSS capsules filled with deuterium–tritium gas fuel at 6 mg/cc density. 1D radiation-hydrodynamic simulations predict higher core compression and, hence, ∼2× higher fusion yield for the 3-shock drive than for 2-shock. Nevertheless, we observe similar core ion temperatures and fusion yields for both drives. The implosion burn duration is 25% shorter and the core volume is ∼2.5× smaller for the 3-shock drive than for 2-shock, consistent with a higher compression. 1D LASNEX mix simulations using a buoyancy-drag model matching the measured yields also agree with the observed core sizes and burn durations and suggest ∼40% and ∼70% yield degradations for 2-shock and 3-shock drives due to hydrodynamic instabilities and atomic mix at the pusher–fuel interface. At the same time, 2D HYDRA simulations show that mid-mode (2–250) instability degradations are negligible for the 2-shock implosion (9%) and significant (45%) for 3-shock. Subtracting these from the 1D mix simulations, we infer similar degradations from high-mode instabilities and atomic mix for both drives. Due to its robustness to mid-mode instabilities, future pusher–gas mix studies will use the 2-shock drive. [ABSTRACT FROM AUTHOR]

This study proposes a feasible solution for boil-off gas (BOG) treatment to facilitate NH3 fuel use by ocean-going ships, which is currently considered an alternative fuel for ships. Two systems were designed and analyzed for BOG in IMO Type-A NH3 fuel storage tanks for 14,000 TEU container ships. First, BOG lost inside the storage tank minimized economic losses through the onboard re-liquefaction system. The total energy consumed by the system to process NH3 gas generated in the fuel tank at 232.4 kg/h was 51.9 kW, and the specific energy consumption (SEC) was 0.223 kWh/kg. Second, NH3 was supplied to the direct Low-Pressure Selective Catalytic Reduction (LP-SCR) system to treat marine pollutants generated by combustion engines. The feasible design point was determined by calculating the NH3 feed flow rate using three methodologies. The energy consumed by the direct LP-SCR system was 3.89 and 2.39 kW, and the SEC was 0.0144 at 0.0167 kWh/kg at 100% and 25% load, respectively. The feasibility was indicated via economic analysis. Depending on the life cycle cost, the competitiveness of the re-liquefaction system depends on the price of NH3, where a higher price yields a more economical solution. In conclusion, the direct LP-SCR system has a low overall cost because of its low energy consumption when supplying NH3 and its reduced amount of core equipment. [ABSTRACT FROM AUTHOR]