O2 Emission Research Articles

Universal Neural Network Potential Driven Molecular Dynamics Study of CO2 and O2 Evolution at the Ethylene-Carbonate/Charged-Electrode Interface

Lithium-ion batteries are currently used in large power sources such as automobiles, for which durability and safety are required. However, LIB suffers from degradation such as CO2 generation from electrolyte decomposition and O2 emission from cathode materials. These side reactions and gas generation can cause serious problems leading to ignition and explosion. It is important to understand how reactions occur at the interface during charging to generate CO2 and O2.This reaction at the cathode/electrolyte interface has been studied by various experimental and computational methods. In particular, density functional theory (DFT) simulation studies are effective in clarifying the decomposition process of the electrolyte at the atomic level. However, DFT calculations for liquid electrolytes are computationally demanding, since the number of molecules are prone to be large when considering molecule-molecule interaction1. To solve, we apply universal neural network potential (UNNP) molecular dynamics (MD) simulations to the reaction at the electrolyte solution / solid electrode interface.In this study, we focused on LixCoO2 (0≤x≤1) and LixNiO2 (0≤x≤1) as cathode materials, and ethylene carbonate (EC) as the electrolyte solvent. The model consists of Li180(1-x)Ni180O360 (Li180(1-x)Co180O360) slab and 100 EC molecules. After the structural relaxation calculations, MD calculations were performed for a 500 ps in a canonical (NVT) ensemble with a time step of 1 fs. Temperatures were 373 K and 473 K, which are below the boiling point of EC.In LiCoO2, no decomposition of the electrode or electrolyte was observed. On the other hand, CO2 was generated in the MD calculation for LiNiO2. The generation process (3 steps) is shown below.(1) Hydrogen dissociation/desorption from EC molecules.(2) Combination of the ethylene group carbon of the EC molecule, from which hydrogen dissociation has occurred, with the oxygen on the cathode surface.(3) Ring-opening between the ethylene group carbon of the EC molecule and oxygen, resulting in CO2 generation.The O2 generation phenomenon was observed to occur in the following three steps as shown in Figure 1.(1) Ni moves to the Li layer to form NiO4 tetrahedron. (Figure 1 (a) → (b))(2) Oxygen dimer is formed by the bonding of NiO4 tetrahedron and NiO5 polyhedron derived from NiO6 octahedron. (Figure 1 (c))(3) Oxygen dimer is released. (Figure 1 (d))Technical details will be presented, in particular on CO2 evolution, at the poster session.

Hopper-air distribution impact on the low-NOx combustion and hopper environment in a 600 MWe staged arch-firing furnace

In today's call for environmental protection and sustainable development, it is urgent to solve the environmental pollution problems caused by industrial coal-fired boilers. Aiming at the ultra-low NO x combustion against with poor burnout and hopper overheating of a 600 MWe arch-firing furnace, this article developed the allocation scheme of hopper air (HA) as the third air-staging layer under a staged arch-firing framework (SAF). Investigations were devoted to the staged HA distribution between the upper and lower HA jets (called the UHA and LHA, respectively). The flow field, coal combustion, NO x emissions, and hopper environment were compared comprehensively at five HA distribution setups of UHA:LHA = 4:6, 5:5, 6:4, 7:3, and 8:2. With increasing moderately UHA to raise the distribution ratio, the comprehensive benefits of the staged HA were obvious. That is, the UHA's function in promoting char combustion was strengthened and again, the roles of LHA to hold up the downward flame and protect hopper were guaranteed. The reductive atmosphere in the reburning zone was maintained at an optimal status added by the staged HA. While these positive improvements were reversed as raising excessively the distribution ratio. Trends of final performance indexes showed that with raising the distribution ratio, residual O2 and CO emission decreased in the whole, while both burnout loss in fly ash and NO output first descended and then ascended. Among the five setups, UHA:LHA = 6:4 gained the best low-NO x combustion merits with NO x output of 582 mg/m3 (O2 = 6%) and unburnt matter in fly ash of 4.97%. Compared with its previous deep-air-staging low-NO x furnace, the SAF incorporating with this optimal staged hopper-air distribution dropped further NO x emissions by 36%, improved combustion, and raised burnout, thereby achieving the simultaneous NO x reduction and burnout improvement. Again, the hopper environment was improved to be moderate-oxygen and low-temperature, alleviating the previous overheating problem to ensure the furnace's safe operations.

Pengaruh Penghalang Pada Intake Manifold Terhadap Emisi Gas Buang Motor Injeksi 125cc

This study aims to analyze the effect of barriers on standard intake manifolds on exhaust emissions in 125cc capacity injection motors. The applied barrier is expected to modify the intake air flow, which has an impact on the combustion process and the resulting exhaust emissions. The method used includes testing exhaust emissions with variations in the use of barriers under several engine conditions, including different engine speeds. The results show that the use of barriers can affect CO, HC, and O2 emission levels, with certain variations indicating changes in combustion efficiency. The conclusion of this research is that the selection of the right barrier diameter and intake manifold shape can contribute to the reduction of exhaust emissions of 125 cc injection motorcycles. The results of this study are expected to be a reference for the automotive industry in designing a more environmentally friendly intake manifold system.

Comparative Analysis of Exhaust Emission of Retrofitted SI Engine Runs by Different Fuels

The purpose of this study was to experimentally inspect the pollutant emission of a retrofitted SI engine using octane, compressed natural gas, and liquefied petroleum gas fuels operated at different speeds. The study was conducted using a retrofitted SI engine. The engine was coupled with an exhaust gas analyzer to measure the composition of the exhaust emission gas. The results showed that the carbon dioxide (CO2) and carbon monoxide (CO) content is lower when CNG is used compared to octane. The CO2 emission was even lower for LPG than CNG, as LPG has a lower carbon-energy ratio and higher octane quality than LPG and burns faster as a lean mixture. The O2 emission supports that octane and CNG burn as a lean mixture whereas LPG burns as rich. Again, the HC emissions are more prominent and CO emissions are higher for LPG than CNG. Because, it showed incomplete combustion with LPG as fuel due to inappropriate air-fuel mixture in the gas-air mixing chamber, which was specifically designed for CNG. Nitrogen oxide (NOx) emission was minimal when the engine was operated with LPG due to incomplete combustion, and it was found maximum for octane, where medium NOx content was found in the case of CNG. Moreover, the relative air fuel ratio or excess air factor, λ increased as the engine operating speed was raised. Because at high speed, there is some turbulence effect and increased combustion duration.

Pengaruh Bentuk Permukaan Piston Rata (Flat) Dan Piston Cembung (Dome) Terhadap Performa Dan Emisi Gas Buang Pada Mesin Sport 200cc

The aim of this research is to determine the effect of engine performance (torque and power), as well as exhaust emissions after replacing the piston. Tests were carried out on a 200CC engine with flat piston specifications with a diameter of 65.0 mm and replaced with a convex piston with a diameter of 65.0 mm using pertalite fuel. The research results obtained by replacing the convex piston (dome) caused the volume of the combustion chamber to decrease resulting in increased torque and power. There was an increase in torque of 0.02607 ft-lbs and an increase in power of 41.95384 HP, then the compression ratio increased by 0.5%. In exhaust gas emissions containing CO, HC, O2, CO2 using a gas analyzer with the results of research on flat pistons and dome pistons, it can be seen that emissions from convex pistons (dome) have increased compared to flat pistons. with the highest increase in stationary of 6.17% in CO emission content due to incomplete combustion residue, which means that the type of piston has a significant influence on exhaust gas emissions. Then the exhaust gas emission test results also show an increase in the O2 emission content on the flat piston at RPM 5000 with a value of 4.24% due to the mixture of oxygen and fuel being more perfect, but on the convex piston (dome) there is a significant increase Compared to a flat piston only at RPM 6500 with a value of 4.53% in O2 emission content. The HC and CO2 emissions content shows unstable or changing values. Apart from that, variations in engine speed also affect the exhaust emissions produced.

Investigation of propane combustion at different equivalent ratios in a premixed model burner

Combustion is a chemical process that causes a burning substance to emit heat and light as a result of its reaction with oxygen. Propane can combine with oxygen to perform a combustion reaction. Especially in homes and vehicles, propane combustion is frequently used and heat or light energy is released. In this study, premixed propane combustion was investigated. The thermal power (3 kW) and swirl number (1) were kept constant in all experiments. According to the findings, the O2 emission value also increases with the increase in propane equivalent. It was observed that if the propane equivalent was up to 0.8, the carbon dioxide emission remained at the optimum level. These results are actually similar in terms of light and heat emission. In fact, it was observed that the heat and Luminous emission and the flame height increased to the highest level at less propane equivalent levels. In the study, it was seen that changing the equivalent ratio affects the ratios of various gases produced during combustion and the total heat output. These experiments help optimize the combustion properties of propane. It is also important for design and operating decisions regarding the use of propane in industrial processes.

Fungal symbionts impact cyanobacterial biofilm durability and photosynthetic efficiency

Cyanobacteria contribute to over 25% of the world's net primary photosynthetic production and are pivotal in mitigating greenhouse gas emissions.1 This study unveils a previously unobserved symbiotic relationship between benthic cyanobacteria and fungi that have also adapted to life as a plant endophyte. The interaction suggests an initial phase of lichenization. We isolated Leptolyngbya frigida from the Naracauli stream, which emanates from abandoned Zn industrial waste in Sardinia. Seasonally, L.frigida participates in a biomineralization processes, mitigating the Zn transfer to rivers and, subsequently, the sea.2,3,4L.frigida is a benthic cyanobacterium that establishes a biofilm on the stream bed. Notably, the area predominantly features Juncus acutus. From these roots, endophytic fungi were predominantly isolated as Clonostachys rosea, a fungus recognized for its biocontrol capabilities against plant pathogens. An intriguing observation was made when L.frigida was cultured with C.rosea on a low-carbohydrate agar medium: the fungal mycelium transformed into wall-less forms, a phenomenon not documented previously. In liquid environments, the resulting biofilm first settled at the container's bottom. Even upon rising to the surface, this biofilm remained pigment rich. Concurrently, a secondary biofilm began its formation at the bottom. These fungal-integrated biofilms displayed enhanced resilience and superior photosynthetic performance compared to those without fungal presence. Moreover, the symbiotic relationship significantly amplified O2 emission and CO2 sequestration by the biofilm.

Probing densified silica glass structure by molecular oxygen and E’ center formation under electron irradiation

This study aims to learn more about the structure of densified silica with focus on the metamict-like silica phase (density = 2.26 g/cm3) by examining the formation of E’ point defects and interstitial molecular oxygen O2 by 2.5 MeV electron irradiation. High-dose (11 GGy) irradiation creates a metamict-like phase and a large amount of interstitial O2, which is destroyed upon subsequent additional lower-dose electron irradiation. The O2 cathodoluminescence (CL) data indicate that the formation of O2 from peroxy linkages Si–O–O–Si in silica network is strongly dependent on the intertetrahedral void sizes. The position and shape of the O2 emission line support the idea that the configuration of these voids in metamict phase is close to that of non-densified silica. Moreover, data support the strong correlation between the formation of 3-membered rings of Si–O bonds and E’-centers when silica density increases from 2.20 to 2.26 g/cm3.

Pengaruh Penambahan methanol Terhadap Emisi Bahan Bakar Mesin Sepeda Motor Berbahan Bakar Pertamax 150 CC

Automotive vehicles have increased every year, especially motorcycles, which result in increased air pollution. The use of alternative fuel methanol is one of the solutions to control air pollution. methanol has a high oxygen content so it can improve emissions. This study aims to analyze the use of a mixture of Pertamax and methanol fuel on exhaust emissions using a 150 cc EFI gasoline engine. The percentage of methanol used in the test is 5%, 10%, and 15%. Variation of engine speed from 1000 to 3000 rpm with an interval of 1000 rpm. Measurement of exhaust emissions using a gas analyzer. The addition of methanol to Pertamax fuel reduced HC emission levels at PM15 by 34% at 3000 rpm and CO by 43% at 3000 rpm at PM15, while CO2 and O2 emission levels increased by 23% at 3000 rpm at CO2, mixing PM15 and at O2 emissions of 163% at a speed of 3000 rpm on PM5.

Lysosomes Targeting pH Activable Imaging-Guided Photodynamic Agents.

Photodynamic therapy (PDT) is a photochemistry-based medical treatment combining light at a specific wavelength and a photosensitizer (PS) in the presence of oxygen. Application of PDT as a conventional treatment is limited and clearly the approval in clinics of new PS is challenging. The selective accumulation of the PS in the targeted malignant cells is of paramount importance to reduce the side effects that are typical of the current worldwide approved PS. Here we report a new series of aniline- and iodine-substituted BODIPY derivatives (1-3) as promising lysosome-targeting and pH-responsive theranostic PS, which displayed a significant in vitro light-induced cytotoxicity, efficient imaging properties and low dark toxicity (for 2 and 3). These compounds were obtained in few reproducible synthetic steps and good yields. Spectroscopic and electrochemical measurements along with computational calculations confirmed the quenching of the emissive properties of the PS, while both fluorescence and 1 O2 emission were obtained only under acidic conditions inducing amine protonation. The pKa values and pH-dependent emissive properties of 1-3 being established, their cellular uptake and activation in the lysosomal vesicles (pH≈4-5) were confirmed by their co-localization with the commercial LysoTracker deep red and light-induced cytotoxicity (IC50 between 0.16 and 0.06 μM) against HeLa cancer cells.

Prediction of reduction products in the preheating process

Under the current requirements of environmental protection, carbon peaking and carbon neutrality goals, the capacity of the new energy interconnection network is increasing day by day. The thermal power unit requires the ability of rapid load adjustment to meet the requirements of real-time power balance. However, when the unit is in a variable load condition, the denitrification system is inefficient or even inoperable. The NOx emission is large, which makes it difficult to meet environmental protection requirements. In this study, a new method for predicting reductive products in the preheating process is proposed, introducing the gasification mechanism into the pulverized coal preheating process. The effects of air coefficient on combustion temperature, velocity, O2, CO2, CO, CH4, and H2, volatile matter and NOx emission are investigated by numerical simulation. It is demonstrated that the gasification mechanism is applicable to predict the reduction products and NOx during preheating. Internal combustion burners can stabilize the precipitation of volatile matter, CH4, CO, and H2. The burner outlet temperature and flow rate decrease with decreasing air coefficient. The local maximum concentration of volatile matter and CH4 are 8.3 vol.% and 2.54 vol.%, respectively. The CO concentration increases with decreasing air coefficient under the effect of CO2 gasification reaction. When the air coefficient is 0.33, the NOx concentration at the burner outlet is 2.8 mg/Nm3 (at 6% O2).

Experimental Investigations and Numerical Modelling of Compression Ignition Engine Fuelled With Diesel and Biodiesel Blend

In this study, diesel fuel and two hundredth by volume of synthesised biodiesel from waste coconut oil (WB20) were used as fuel in unmodified, naturally aspirated, single cylinder compression ignition engine to study their performance and combustion characteristics at full load condition. Numerical studies were carried out with the use of CFD and compiled with the experimental results. FORTE software was used for CFD simulation. Methyl-palmitate (MPA) and Dodecane (C12H26) were used as surrogate fuels for biodiesel and diesel fuel respectively. The variation of special parts for diesel fuel and WB20 with CI engine in-cylinder pressure, in- cylinder temperature and mass fraction of O2, CO and NO emission at 10p and 20p ATDC were analysed. The mass fraction contours of in-cylinder temperature, O2, CO and NO for diesel fuel and WB20 were found to be decreased with increase in crank angle from 10o to 20° ATDC. The maximum BTE, in-cylinder pressure, in-cylinder temperature, O2, CO2 and NO were obtained for WB20 at 10° ATDC.

A Review on Computational Fluid Dynamics Simulations of Industrial Amine Absorber Columns for CO2 Capture

AbstractCO2 emission is an important environmental issue leading to global climate change, notably an increase in global temperatures; therefore, it is so imperative to reduce CO2 emissions to the atmosphere. Absorption columns using amine‐based solutions are a promising approach for CO2 removal from industrial gas streams. Many modeling and simulation research have been performed on CO2 absorption columns in which computational fluid dynamics (CFD) strategy is very appropriate and well‐known. As CFD modeling and simulation is a fast‐developing method, the most recent review papers do not include the core research in this field of study. In this study, numerical simulations of CO2 absorption columns using CFD strategy have been carried out applying various types of amine‐based solutions. Furthermore, the effect of various types of packing mesh generation on the absorption columns' efficiency was studied. Investigation of synergetic influence such as application of various nanoparticles in different amine‐based solutionsand activators, double diameter packed bed absorption columns with different packings, rotating packed columns with double diameter are proposed for future studies.

Co-firing characteristics and fuel-N transformation of ammonia/pulverized coal binary fuel

As a feasible way to decarbonize coal combustion under the background of carbon neutrality in recent years, ammonia co-firing with pulverized coal is receiving considerable critical attention from the academic and industrial communities. This paper investigates the effects of coal type, NH3 injection mode, temperature, excess air ratio (α) and NH3 co-firing ratio (ENH3) on combustion characteristics and fuel-N transformation of ammonia/pulverized coal in a 6 kW drop tube furnace. Emission of O2, CO2, CO, NO, NO2 and NH3 at the furnace exit was monitored online. The unburned carbon (UBC) content and elementary composition in fly ash were also tested. Results show that NOx generation behaviors of premixed and staged modes are significantly different. Typically, NOx emission peaks at ENH3 = 20 % under high temperature and staged mode. As for NH3/coal cases at 1000 °C, NOx level is even lower than pure coal combustion, but NH3 residue is higher. The water gas shift reaction (WGSR) under fuel-rich condition generates more CO, and the conversion ratio from fuel-N to NOx decreases when α diminishes. Ammonia co-firing can achieve lower CO emission with anthracitic coal from Gongyi (GY-coal) while lower NOx emission with bituminous coal from Inner Mongolia (IM-coal). Ammonia co-firing can considerably improve the transformation from fuel-N to N2. From the perspective of emission control and decarbonization, ENH3 = 40 % is an optimal ammonia co-firing ratio which not only can reduce half of CO2 but also brings the conversion ratio from fuel-N to NOx and residual NH3 to the minimum level. The micromorphology of ash samples is greatly affected by coal/ammonia co-firing. In premixed mode, the surface of ash sample is porous and adhered to each other; while in staged mode, obvious fractures and cuts exist between the ash particles due to the sharp decrease of local gas temperature.

Colorless distributed combustion characteristics of hydrogen/air mixtures in a micro combustor

Colorless distributed combustion technique enables less pollutants emissions for a fuel/oxidizer mixture to be combusted. In this study, colorless distributed combustion characteristics (CDC) of hydrogen/air mixtures were numerically investigated in a micro combustor to overcome the difficulties associated with micro combustion and to obtain a more uniform temperature profile on the outer wall. To that end, hydrogen/air combustion was simulated by using ANSYS/Fluent CFD code at a constant equivalence ratio (1.0) and thermal input (100 W) and different mixture inlet temperatures of 300 K, 600 K and 1000 K to seek colorless distributed combustion. CDC conditions were tried to be achieved by decreasing the oxygen concentration from 21 % to 9 % at an interval of 3 %. In conclusion, colorless distributed combustion conditions could be achieved at different O2 concentrations, irrespective of the mixture inlet temperature. At 300 and 600 K, such conditions did not make any positive contribution to the power output of the micro combustor. Nevertheless, at 1000 K and 9 % O2 concentration, all combustion and emission performance metrics were improved in a manner that could increase the power output of the micro power generator.

The Effect of Bioethanol and Pertamax Mixtures on Exhaust Gas Emissions from a 4-Stroke Engine in Motorcycle Matic

Bioethanol is an alternative fuel to substitute fossil oil. Bioethanol has several advantages in its use as a fuel in addition to its renewable nature, and bioethanol is also believed to reduce some motor vehicle emissions. The purpose and objective of this study were to determine the effect of a mixture of Bioethanol and Pertamax on gas emissions in a 4-stroke motor with variations in the fuel mixture and engine cycle. This test method is carried out with the measurement parameters of CO, HC, CO2, and O2. Tests on motor vehicles were carried out with variations of BP0 (0% Bioethanol) to BP100 (100% Bioethanol). The test results using a gas analyzer and analyzed using excel show that bioethanol cannot reduce exhaust gas emissions. Adding bioethanol fuel to Pertamax can also increase the fuel's octane number (RON) and specific gravity. From the available data, adding bioethanol can reduce HC emission levels by up to 4ppm at BP50 at 6000 rpm, increasing CO2 emissions by 13.4% at BP50 at 7000 rpm with a compression ratio of 13:1. For the lowest O2 emission level, it reaches 0.13%. at BP40 at 5000 rpm. CO emission levels are still relatively small in various mixtures with a yield of 0.01%, but at BP0 and BP80 at 13:1 compression, emissions tend to increase every rpm.

Experimental Investigation in Compression Ratio on Performance, Combustion and Emission of VCR Engine using Pyrolysis-oil Produced from Waste Plastic Materials

The generation of waste plastic is one of the major concerns for the scientific community due to its non biodegradable nature. Plastic has been primarily used in different packaging sectors across the globe and polyolefins are primarily used for this purpose to mitigate the demand. However, the lower recycling rate of waste plastics creates several long-term issues in the ecosystem. Therefore, reducing the waste plastic and producing some valuable chemicals is one of the ideal directions to overcome this issue.In this study, we have reported the production of liquid fuels from waste plastics material through thermo-chemical conversion and analyzed for engine performance, combustion, and emission characteristics in compression ignition (CI) engine. The liquid product (or pyro-oil) was characterized by different ASTM standard methods to evaluate the fuel properties. Finally, fuel was used at 10 and 20% blending with commercial diesel to analysis the engine performance, combustion and emission at varying brake mean effective pressure and compression ratio. The results revealed that blending of PO reduces brake specific fuel consumption (BSFC) to achieve the same power. Comparing with commercial diesel, the blended fuels showed better brake power, brake thermal efficiency, mechanical efficiency, cylinder pressure, net heat release rate, and exhaust gas emission. An enhancement in BTE and ME with increasing in BMEP was observed and varies in the range of ∼ 0–34% and ∼ 0–95%, respectively. The blending of PO significantly reduces the emissions of CO, CO2, NOx and un-burnt hydrocarbon as well as improved the O2 emission. Reduced CO emission means a better lifestyle as the health risks factor is also reduced because inhalation of CO can form carboxyhemoglobin (COHb or HbCO) by dissolving in hemoglobin and restrict the oxygen circulation from lungs to the tissues that causes several health issues including death of a person.

Evaluation of the association between plasma glucose-dependent insulinotropic polypeptide, respiratory quotient, and intramuscular fat deposition in feedlot cattle fed different levels of dry matter intake.

The objectives of this trial were to evaluate the association between different levels of dry matter intake (DMI) on gas exchange, plasma glucose-dependent insulinotropic polypeptide (GIP) concentration, and intramuscular (IM) fat deposition. We used 60 individually fed backgrounded Angus × SimAngus-crossbred steers (n = 30) in a randomized complete block design. Steers (paired by body weight [BW] and gain to feed ratio [G:F]) were randomly allocated to one of the following treatments: ad libitum intake (AI) or restricted intake (RI; the same diet fed at 85% of the AI) of a finishing diet. The diet contained 61% cracked corn, 9% corn silage, 15% distillers’ dried grains with solubles, 5% soyhulls, and 10% of a protein-mineral-vitamin premix. Measurements of CO2 emission and consumption of O2, and respiratory quotient (RQ) were taken using the GreenFeed system (n = 15/treatment). Plasma and gas samples were collected 10 d before slaughter, 1 h before and 2 h after feeding. Plasma glucose, non-esterified fatty acids, GIP, and insulin concentration and gasses (O2, CO2, and RQ) were analyzed using the MIXED procedure of SAS evaluating the fixed effect of treatment, time (repeated measurement) and their interaction, and the random effect of the block. Final BW and carcass characteristics were analyzed with a similar model, without the time statement and its interaction. Compared with RI, AI steers had greater (P < 0.01) DMI and average daily gain (ADG). Steers on AI had greater final BW (P = 0.02), tended to have a greater ribeye area (P = 0.09), and had lower plasma GIP concentration (P = 0.04). There was no treatment effect (P ≥ 0.11) on G:F, subcutaneous backfat (BF), and IM fat, O2 consumption, CO2 emission, and RQ. Plasma glucose concentration of AI steers was greater before and after feeding than RI (P < 0.05). In conclusion, feeding steers ad libitum increased DMI, ADG, and plasma glucose and GIP concentration but does not affect G:F, BF, IM fat, CO2 emission, and O2 consumption. Plasma GIP concentration and RQ are not associated with IM fat deposition.

Establishing an appropriate overfire air angle at the furnace throat of a low-NO W-shaped flame furnace

A cascade-arch-firing low-NOx and high-burnout configuration (CLHC) was developed as a solution for a 600 MWe W-shaped flame furnace suffering from poor burnout under ultra-low NOx combustion conditions. Under the comprehensive low-NOx combustion conditions regulated by the CLHC, overfire air (OFA) was first positioned at the furnace throat in a uniformly flattening OFA port form along the furnace breadth direction. In order to disclose the OFA angle’s effect on the furnace performance and meanwhile establish an appropriate angle for the OFA with the above original designs, the in-furnace flow field, coal combustion, and NOx emissions were evaluated at various OFA angles of θ = 10°, 20°, 25°, 30°, and 35°. Increasing θ only changed a little the symmetry of flow field and combustion morphology, i.e., the symmetry generally deteriorating first and then improving. The OFA penetration in the furnace throat zone initially increased but then worsen as θ increased. In the upper furnace strongly affected by OFA, gas temperatures, high-temperature zone area, and levels of O2 and CO all descended first and then increased with θ, while NO generally undergone an increase-to-decrease trend. Trends of furnace outlet’s performance indexes with θ showed that the residual O2 and CO emission generally decreased first and then increased, NOx emissions initially increased but then decreased, while carbon in fly ash undergone an increase-to-decrease trend prior to an increase at θ = 35°. In view of the above findings and the gained optimal low-NOx and high-burnout performance (NOx emissions of 667 mg/m3 at 6% O2 and carbon in fly ash of 5.31%), θ = 30° was taken as an appropriate OFA angle for the CLHC furnace. Compared with a currently advanced low-NOx combustion art, the CLHC reduced further NOx emissions by 26.3% while remained a high burnout achievement.

Reverse Electron Transfer is a More Dominant Source of Mitochondrial ROS Production in the Heart and Kidney Outer Medulla than in the Kidney Cortex

RationaleReactive oxygen species (ROS; e.g. O2·– and H2O2) play important roles in both physiological and pathophysiological processes. ROS in low concentrations contribute to physiological processes, such as cellular redox signaling and phagocytosis, whereas ROS in high concentrations are toxic to the cell causing tissue injury contributing to the pathogenesis of cardiovascular and chronic renal diseases, including salt‐sensitive hypertension. Mitochondria, which produce ROS as byproducts of aerobic respiration via both forward electron transfer (FET) and reverse electron transfer (RET) are known to be one of the major cellular sources of ROS. Although it is recognized that the RET mechanism in which electrons flow back from complex II to complex I contribute significantly to ROS production in cardiac mitochondria, the mechanisms of ROS production and the role of RET in kidney mitochondria has remained poorly understood.MethodWe evaluated the relative contributions of FET and RET towards overall ROS production in mitochondria isolated from the heart and kidney cortex and outer medulla (OM) of adult Sprague‐Dawley rats. H2O2 emission was measured by a spectrofluorometer in isolated mitochondria in the presence of either Succinate (Suc) simulating RET or succinate+rotenone (Suc+Rot) simulating FET. Furthermore, we measured mitochondrial rates of H2O2 production along with respiration and membrane potential under three respiratory states namely (i) leak state (state 2; after substrate addition), (ii) oxidative phosphorylation (OxPhos) state (state 3; after ADP addition), and (iii) maximum respiratory state (state 5; after the addition of the uncoupler FCCP).ResultsIt was found that mitochondria isolated from the heart and kidney cortex produced the least and the most ROS, respectively. The rate of ROS production in the presence of Suc+Rot compared to Suc alone decreased significantly in the heart and to a lesser extent in OM, indicating significant contribution of RET to overall ROS production in the heart and slightly in the OM. In contrast, there was not significant difference in ROS production rates in the presence of Suc and Suc +Rot in mitochondria from kidney cortex, showing that RET is not predominant in the kidney cortex. Also, we observed significant reduction in the ROS production rate in state 4 compared to state 2 in the heart mitochondria compared to kidney cortex and OM. A possible explanation for these differential results is that oxaloacetate (OAA), produced by the tricarboxylic acid cycle, accumulates resulting in succinate dehydrogenase (SDH) inhibition more rapidly in the heart than in the kidney affecting mitochondrial ROS production, respiration, and bioenergetics.ConclusionRET mechanism contributes to mitochondrial ROS production significantly in the heart and slightly in the kidney OM, but not in the kidney cortex. OAA accumulation contributes to SDH inhibition significantly in the heart than in the kidney.