Nitrogen Emissions Research Articles

High contribution of anthropogenic combustion sources to atmospheric inorganic reactive nitrogen in South China evidenced by isotopes

Abstract. Due to the intense release of reactive nitrogen (Nr) from anthropogenic activity, the source layout of atmospheric nitrogen aerosol has changed. To comprehensively clarify the level, sources, and environmental fate of NH4+ and NO3-, their concentrations and stable isotopes (δ15N) in fine particulate matter (PM2.5) were measured in a subtropical megacity of South China. The inorganic nitrogen (NH4+ and NO3-) was an essential part of atmospheric nitrogen aerosol, and the N-NH4+ and N-NO3- contributed 45.8 % and 23.2 % to total nitrogen (TN), respectively. The source contributions of NH4+ and NO3- were estimated by δ15N, suggesting that the dominant sources were from anthropogenic combustion activities, including coal combustion, biomass burning, and vehicles, contributing 63.2 % and 88.3 % to NH4+ and NO3-, respectively. In particular, biomass burning was the predominant source of NH4+ (27.9 %), whereas coal combustion was the dominant source of NO3- (40.4 %). This study emphasized the substantial impacts of human activities on inorganic Nr. With the rapid development of industry and transportation, nitrogen emissions will be even higher. The promotion of clean energy and efficient use of biomass would help to reduce nitrogen emissions and alleviate air pollution.

Evaluating the effects of plastic film mulching duration on soil nitrogen dynamic and comprehensive benefit for corn (Zea mays L.) field

Regulating the plastic film mulching duration was a good strategy to decrease plastic residues and to avoid the stress from low soil nitrate concentration (SNC). However, few studies focused on soil nitrogen dynamic under different mulching durations, especially for the impacts of soil nitrogen loss on crop yield and comprehensive benefits have not been revealed. In this study, HYDRUS (2D/3D) model was used to evaluate the differences of SNC and NO3-N leaching (NL) under no mulching (NM), mulching for the seedling stage (PMS), mulching for the elongation stage (PME), mulching for the tasseling stage (PMT), and mulching for the entire corn growth season (PMW). Additionally, a two-year (2019–2020) field experiment was carried out to measure SNC, NL, N2O, and NH3 emissions and to calibrate and validate the model accuracy. The effect of soil nitrogen loss on the comprehensive benefits under different mulching durations was further analyzed using a comprehensive multi-objective model. The results showed that HYDRUS (2D/3D) could well capture SNC dynamic under different mulching treatments, with average the normalized root mean square error of 16.5% in the validation period. There was no apparent difference in SNC, N2O emission, NH3 emission, and NL under different mulching durations in the seedling stage. However, the corresponding difference markedly increased with corn growth and development, especially in 2019. The average SNC (0–20 cm soil depth) under NM was higher by 9.2%, 25.0%, 21.2%, and 19.4% than PMS, PME, PMT, and PMW, respectively. Nitrogen emission (N2O and NH3) showed an increase trend with the shortening of mulching duration, i.e., NM>PMS>PME >PMT >PMW, while an opposite trend was found for NL. In general, PME was found to be the optimal mulching duration with the highest comprehensive evaluation score of 1782.7. Therefore, PME can be recommended to apply in this region to promote the developments of sustainable agriculture.

Simultaneous dissolved methane and nitrogen removal from low-strength wastewater using anaerobic granule-based sequencing batch reactor

Anaerobic treatment of mainstream wastewater has been proposed as a promising solution to enhance bioenergy recovery for wastewater treatment plants (WWTPs). However, the limited organics for downstream nitrogen removal and emissions of dissolved methane into the atmosphere are two major barriers to the broad application of anaerobic wastewater treatment. This study aims to develop a novel technology to overcome these two challenges by achieving simultaneous removal of dissolved methane and nitrogen, and unravel the microbial competitions underpinning the process from the microbial and kinetic perspectives. To this end, a laboratory granule-based sequencing batch reactor (GSBR) coupling anammox and nitrite/nitrate-dependent anaerobic methane oxidation (n-DAMO) microorganisms was developed to treat wastewater mimicking effluent from mainstream anaerobic treatment. The GSBR achieved high-level nitrogen and dissolved methane removal rates (> 250 mg N/L/d and > 65 mg CH4/L/d) and efficiencies (> 99% total nitrogen removal and > 90% total methane removal) during the long-term demonstration. The availability of different electron acceptors (nitrite or nitrate) imposed significant effects on the removal of ammonium and dissolved methane, as well as on the microbial communities, and the abundance and expression of functional genes. The analysis of apparent microbial kinetics showed that anammox bacteria had a higher nitrite affinity than n-DAMO bacteria, while n-DAMO bacteria had a higher methane affinity than n-DAMO archaea. These kinetics underpin the observation that nitrite is a preferred electron acceptor for removing ammonium and dissolved methane than nitrate. The findings not only extend the applications of novel n-DAMO microorganisms in nitrogen and dissolved methane removal, but also provide insights into microbial cooperation and competition in granular systems.

Performance and Emission Characteristics for Karanja Biodiesel Blends Assisted With Green Hydrogen Fuel and Nanoparticles

Abstract Extensive efforts are being made to produce and use a variety of alternative energies in order to meet the rising global energy demand. The main purpose of this research was to evaluate the mass fuel burnt, emissions, and performance properties of biodiesel made from non-edible karanja oil along with hydrogen and nanoparticles in a standard diesel engine. Upon experimental evaluation, it was determined that the transesterified karanja oil retained all of its vital physicochemical properties within the specified tolerances. The emission and performance characteristics of karanja biodiesel blended with nanoparticles and hydrogen fuel were assessed at different engine loads ranging from 0% to 100%. The uniform amount of nanoparticles and hydrogen was incorporated into test fuels. Al2O3 nanoparticles of 50 ppm were used in this study and hydrogen of 5 L/min was supplied to the engine. K20NH test fuel had the maximum brake thermal efficiency and less brake-specific fuel consumption compared to the other fuel blend. The emissions were considerably reduced on karanja oil, nanoparticles, and hydrogen-blended biodiesel except for nitrogen emission compared with conventional diesel fuel. In this study, the utilization of karanja, nanoparticles, and hydrogen-blended biodiesel showed a promising alternative to fossil fuels due to reduced emission and enhanced performance characteristics.

NOx and N2O emissions from Ca-rich fuel conversion in oxyfuel circulating fluidized bed combustion

A part of Estonia’s power generation is based on oil shale combustion in thermal power plants, resulting in high CO2 and pollutant emissions. The presented paper is a part of long-term experimental work to investigate the combustion of Ca-rich oil shale for air and oxyfuel combustion environments. The experiments were performed in a 60 kWth circulating fluidized bed (CFB) test facility under air, O2/CO2, and O2 with the recycled flue gas (RFG) modes of inlet O2 as vol.% ranging from 21% to 52%, and with RFG of 50% and 87%. The influence of different combustion atmospheres, excess oxygen volumetric ratios in the primary oxidizer (λPr), and dense bed temperatures (TDB), on the total NOx and N2O formations, have been studied in detail.The results show that specific concentrations of NOx (per MJ) were reduced by 14% in O2/CO2 mode, and 22% in O2/RFG compared to air combustion. N2O emissions were increased in OXY21 mode and reduced significantly from 20 mg/MJ to 4 mg/MJ with increasing inlet O2% to 52% under O2/CO2. NOx and N2O emissions were the lowest of all combustion experiments at high inlet O2% with RFG application (OXY87 + RFG). Under all tested atmospheres, NOx emissions were increasing with increasing excess oxygen in the primary oxidizer. N2O enhanced with excess oxygen, accounted for the homogenous gas-phase reaction of volatile-N and the heterogenous reaction of char-N. NOx emissions at low operating TDB were decreasing with increasing bed temperatures and increased at higher TDB > 770 °C in air combustion and TDB > 850 °C in OXY30. N2O emissions were slightly decreased at higher bed temperatures under air and O2/CO2 modes. Combustion efficiency enhanced at higher inlet O2% resulting in lower CO concentrations with reduced fuel burnout, and increased NOx and N2O emissions.Overall, NOx and N2O formations were more affected by the condition of operating parameters under both air and oxyfuel combustion experiments, and the obtained results are giving confidence that oxyfuel technology does not influence the release of nitrogen emissions from oil shale combustion. To lower the cost of CO2 impurities removal, the optimal operating conditions during oil shale CFB combustion can be confirmed after considering the discussed parameters. However, further CO2 purification resulting from oil shale oxyfuel flue gas stream is possibly required.

Precipitation trend increases the contribution of dry reduced nitrogen deposition

Given the leveling off in oxidized nitrogen emissions around the world, the atmospheric deposition of reduced nitrogen (NHx = NH3 + NH4+) has become progressively critical, especially dry deposition, which presents great threats to plant growth. A combination of historical deposition data of measured wet NHx and modeled dry NHx in China suggests that dry NHx deposition has been increasing substantially (4.50% yr−1, p < 0.05) since 1980. Here, chemical transport model (WRF-EMEP) results indicate that variation in NH3 emissions is not a dominant factor resulting in the continually increasing trends of dry NHx deposition, while climate change-induced trends in precipitation patterns with less frequent light rain and more frequent consecutive rain events (with ≥2 consecutive rainy days) contribute to the increase in dry NHx deposition. This will continue to shift NHx deposition from wet to dry form at a rate of 0.12 and 0.23% yr−1 (p < 0.05) for the period of 2030–2100 in China under the RCP4.5 and RCP8.5 scenarios, respectively. Further analysis for North America and Europe demonstrates results similar to China, with a consistent increase in the contribution of dry NHx deposition driven by changing precipitation patterns from ~30% to ~35%. Our findings, therefore, uncover the change of precipitation patterns has an increasing influence on the shifting of NHx deposition from wet to dry form in the Northern Hemisphere and highlight the need to shift from total NHx deposition-based control strategies to more stringent NH3 emission controls targeting dry NHx deposition in order to mitigate the potential negative ecological impacts.

Social interactions, precursors of damaging behaviours, object manipulation, straw rooting, and activity: a detailed data set in undocked pigs under protein restriction

Damaging behaviours, such as tail biting, are common problems in pig production, compromising animal welfare and causing economic losses. Detailed studies are impeded by laborious direct observations. Tail biting is a broader phenomenon that begins long before lesions manifest, and behavioural problems caused by various stressors present themselves weeks before they escalate to damaging behaviour. Therefore, we collected detailed data on behaviours considered precursors to tail biting, such as oral and nasal manipulation of conspecifics. Dietary protein reduction is a promising way to reduce nitrogen emissions in pig manure, but its implications for animal welfare are not yet clear. The CP content in the diet was reduced to 80% of the recommendations. Pigs differ in their ability to utilise dietary proteins; therefore, there might be individual differences in how they cope with the protein reduction. Here, we present detailed data of focal observations of 95 pigs at an experimental farm with undocked tails. Pigs were observed directly by the same person for five minutes on four different days. All actions directed towards objects in the pen, interactions with and confrontations among pen mates, straw rooting behaviour and general activity were recorded. After the behavioural observations, wounds on different body parts and the cleanliness were noted by the same person observing the pigs. The protein efficiency of 94 pigs was obtained. The data set comprises six tables. The first table contains information on the animals, including the identities of their parents, farrowing group, sex, and protein efficiency. The other data tables contain four 5-min observations of each pig on 10 object-manipulation behaviours; 150 interaction behaviours, including reactions; 14 confrontation behaviours and their outcomes and reactions; 10 mounting behaviours, including reactions; two rooting behaviours; seven basic behaviours; and an index of general activity. The observations took place under comparatively good housing conditions. Pigs were given fresh straw daily, ad libitum access to feed, floor space above the legal requirements, and daily cleaning of pens, and they were closely monitored for signs of damaging behaviour; all of these are favourable conditions as they limit stress and the risk of damaging behaviour. These data can be used to further explore the relationships of specific behaviours and phenomena and their association with protein efficiency. The ethogram can be used as a template for further observations. Practitioners could use the data to support pigs’ need for occupation, such as by providing sufficient straw.

ANN-based prediction of ammonia nitrogen for wastewater discharge indicators under carbon neutral trend

IntroductionWith the rapid development of society and urbanization, greenhouse gas emissions have increased, leading to environmental problems such as global warming. The rise in urban water consumption has also resulted in increased sewage discharge, exacerbating freshwater scarcity and water pollution. Understanding the current status and spatial distribution of greenhouse gas emissions in China's sewage treatment industry is crucial for emission reduction measures and controlling ammonia nitrogen pollution.MethodsThis study comprehensively investigates greenhouse gas emissions from sewage treatment plants, analyzing influencing factors and predicting future spatial and temporal distributions. The uncertainty of ammonia nitrogen emissions is calculated using the IPCC's error propagation method, considering uncertainty ranges of variables. Additionally, an artificial neural network is employed to predict ammonia nitrogen content in sewage discharge, aiming to prevent excessive levels in wastewater.Results and discussionThe proposed model outperforms others with an R-Squared score of 0.926, demonstrating its superior accuracy in predicting ammonia content in wastewater. These findings contribute to better emission reduction strategies and control of ammonia nitrogen emissions. This model can effectively prevent excessive ammonia nitrogen content in discharged wastewater, contributing to water pollution control. In conclusion, this study highlights the importance of understanding greenhouse gas emissions from sewage treatment plants and their impact on water pollution. The research provides valuable insights into emission reduction measures, emission prediction, and technological innovations suitable for China's specific conditions. By effectively managing ammonia nitrogen emissions and adopting the proposed predictive model, the goals of carbon neutrality and environmental sustainability can be better achieved.

Yield- and protein-neutral reduction in fertilizer rate for wheat, maize and rice can reduce the release of reactive nitrogen and greenhouse gas emissions in China

Seeking food security, contemporary Chinese agriculture has followed a trajectory of overfertilization and associated environmental problems, hence the need for nitrogen-balancing practices that do not compromise yield and quality. Here we present a national meta-analysis using 224 studies with 1972 comparisons to quantify the potential to reduce nitrogen (N) fertilization to improve environmental outcomes while maintaining yield and grain protein. We calculated a nitrogen reduction ratio (NRR), as 100 × (N C − N T)/N C; where N is N fertilizer rate and subscripts indicate farmer practice (C) and reduced N rate treatment (T). Our meta-analysis showed that the NRR that maintained yield and grain protein content at the level of current practice was up to 10% in wheat and up to 30% in maize and rice. Larger yield-neutral NRR could be achieved in more fertile, heavier-textured soils, and with practices including enhanced-efficiency N fertilizer, combined application of organic and inorganic N fertilizer, and incorporated straw. Assuming a reduction in N fertilizer usage by 10% for wheat and by 30% for maize and rice in the current cropping area, there is a potential to save 5.7 Mt N yr−1; reduce loss of reactive nitrogen by 1.26 Mt N yr−1, equivalent to 63% of annual total Nr losses for rice in China, reduce N-related greenhouse emissions by 75.2 Mt CO2-eq yr−1, equivalent to 14.5%–25% of the emissions associated with the N fertilizer chain in China; and improve N use efficiency by 23%. Our results highlight the feasibility of maintaining yield and grain protein, and achieving substantial environmental benefits with reduced fertilization rate, and the environmental and agronomic scenarios where these outcomes are more likely.

JWST/NIRSpec Measurements of the Relationships between Nebular Emission-line Ratios and Stellar Mass at z ∼ 3–6

We analyze the rest-optical emission-line ratios of star-forming galaxies at 2.7 ≤ z < 6.5 drawn from the Cosmic Evolution Early Release Science (CEERS) Survey and their relationships with stellar mass (M *). Our analysis includes both line ratios based on the [N ii] λ6583 feature ([N ii] λ6583/Hα, ([O iii] λ5007/Hβ)/([N ii] λ6583/Hα) (O3N2), and [N ii] λ6583/[O ii] λ3727) and those featuring α-elements ([O iii] λ5007/Hβ, [O iii] λ5007/[O ii] λ3727 (O32), ([O iii] λλ4959, 5007 + [O ii] λ3727)/Hβ (R23), and [Ne iii] λ3869/[O ii] λ3727). Given the typical flux levels of [N ii] λ6583 and [Ne iii] λ3869, which are undetected in the majority of individual CEERS galaxies at 2.7 ≤ z < 6.5, we construct composite spectra in bins of M * and redshift. Using these composite spectra, we compare the relationships between emission-line ratios and M * at 2.7 ≤ z < 6.5 with those observed at lower redshift. While there is significant evolution toward higher excitation (e.g., higher [O iii] λ5007/Hβ, O32, O3N2) and weaker nitrogen emission (e.g., lower [N ii] λ6583/Hα and [N ii] λ6583/[O ii] λ3727) between z ∼ 0 and z ∼ 3, we find in most cases that there is no significant evolution in the relationship between line ratio and M * beyond z ∼ 3. The [Ne iii] λ3869/[O ii] λ3727 ratio is anomalous in showing evidence for significant elevation at 4.0 ≤ z < 6.5 at fixed mass, relative to z ∼ 3.3. Collectively, however, our empirical results suggest no significant evolution in the mass–metallicity relationship at 2.7 ≤ z < 6.5. Representative galaxy samples and metallicity calibrations based on existing and upcoming JWST/NIRSpec observations will be required to translate these empirical scaling relations into ones tracing chemical enrichment and gas cycling and to distinguish among descriptions of feedback in galaxy formation simulations at z > 3.

Use of life cycle assessment and modeling techniques for prediction of energy-environmental indicators in different wheat production systems

This study was conducted to analyze and model the energy consumption and environmental indicators for different wheat production systems in Qazvin province. Information needed for this study, related to 2021–2022, data was collected by monitoring machinery, and inputs during wheat production were interviewed by farmers and filled out questionnaires. The purpose of this study includes: (1) estimating the fuel consumption and energy of inputs in different wheat production systems, (2) estimating the environmental impact associated with input consumption using life cycle assessment (LCA), and (3) providing suggestions for optimization. The results showed wheat production in irrigated conservation tillage system has energy ratio (2.12) and energy productivity (0.18 kg MJ−1) suitable compared to conventional irrigated and rainfed tillage, and conservation rainfed tillage. Nitrogen fertilizer (55%–68%) and fuel consumption (15%–31%) of affect the energy consumption of four wheat cultivation systems. Three categories of damage to human health, ecosystem and resources in LCA were using the ReCiPe2016 method. Resource damage category for conventional tillage irrigation (76.05 USD2013) has significant pollution. The share of seed emissions, On-Farm emissions and nitrogen emissions affect the categories of damage to human health, ecosystems and resources, respectively. The results of the Cobb-Douglas model showed that T3 (fertilization and weed control) was significant at the level of 1% among other inputs. T1 (chisel packer roller), T2 (planting) and T4 (harvest and straw packaging) were significant at 5% level. The results of artificial neural network (ANN) of conventional rainfed cultivation showed that 6 input layers, 7 hidden layers with 10 hidden neurons and 1 output parameter were selected as the best structure. R2 and RMSE for fuel consumption were 0.95 and 43.65, respectively. As a result, the ANN results show higher accuracy than the Cobb-Douglas model.

The environmental impact and development direction of grass carp, Ctenopharyngodon idella, aquaculture

AbstractGrass carp, Ctenopharyngodon idella, is the largest freshwater aquaculture fish species worldwide. However, its environmental impacts are increasingly controversial. In this paper, we considered the production of a 1500 g commercial grass carp as an example, analyzed through a life cycle assessment. The results showed that the indicators of global warming potential (GWP), acidification potential, eutrophication potential, freshwater eco‐toxicity potential (FAETP), land competition (LC), and fossil energy consumption of producing 1 kg of grass carp were equivalent to 5.7267 kg of CO2, 0.0648 kg of 1,4‐DCB0, 0.0010 kg of P, 0.0276 kg of SO2, 8.2951 m2, 0.3491 kg of oil, respectively, and were mainly from feed processing and water pollution. Compared with pig, beef, and sheep production, grass carp production has lower environmental impacts, but in terms of GWP, FAETP, and LC were significantly higher than chicken production, especially water pollution and discharge, which is an important consideration. This study clarifies the direction of grass carp production and key focus areas include producing low carbon and nitrogen emission feed, application of ecological engineering aquaculture system, intelligent mechanization technology and equipment.

Nitrogen enhancements 440 Myr after the big bang: supersolar N/O, a tidal disruption event, or a dense stellar cluster in GN-z11?

ABSTRACT Recent observations of GN-z11 with JWST/NIRSpec revealed numerous oxygen, carbon, nitrogen, and helium emission lines at z = 10.6. Using the measured line fluxes, we derive abundance ratios of individual elements within the interstellar medium (ISM) of this superluminous galaxy. Driven by the unusually-bright N iii] λ1750 and N iv] λ1486 emission lines (and by comparison, faint O iii] λλ1660, 1666 lines), our fiducial model prefers log (N/O) &amp;gt; −0.25, greater than four times solar and in stark contrast to lower-redshift star-forming galaxies. The derived log (C/O) &amp;gt; −0.78, (≈30 per cent solar) is also elevated with respect to galaxies of similar metallicity (12 + log (O/H) ≈ 7.82), although less at odds with lower-redshift measurements. We explore the feasibility of achieving these abundance ratios via several enrichment mechanisms using metal yields available in the literature. Given the long time-scale typically expected to enrich nitrogen with stellar winds, traditional scenarios require a very fine-tuned formation history to reproduce such an elevated N/O. We find no compelling evidence that nitrogen enhancement in GN-z11 can be explained by enrichment from metal-free Population III stars. Interestingly, yields from runaway stellar collisions in a dense stellar cluster or a tidal disruption event provide promising solutions to give rise to these unusual emission lines at z = 10.6, and explain the resemblance between GN-z11 and a nitrogen-loud quasar. These recent observations showcase the new frontier opened by JWST to constrain galactic enrichment and stellar evolution within 440 Myr of the big bang.

Effects of Nitrogen Emissions on Fish Species Richness across the World's Freshwater Ecoregions.

The increasing application of synthetic fertilizer has tripled nitrogen (N) inputs over the 20th century. N enrichment decreases water quality and threatens aquatic species such as fish through eutrophication and toxicity. However, the impacts of N on freshwater ecosystems are typically neglected in life cycle assessment (LCA). Due to the variety of environmental conditions and species compositions, the response of species to N emissions differs among ecoregions, requiring a regionalized effect assessment. Our study tackled this issue by establishing regionalized species sensitivity distributions (SSDs) of freshwater fish against N concentrations for 367 ecoregions and 48 combinations of realms and major habitat types globally. Subsequently, effect factors (EFs) were derived for LCA to assess the effects of N on fish species richness at a 0.5 degree × 0.5 degree resolution. Results show good SSD fits for all of the ecoregions that contain sufficient data and similar patterns for average and marginal EFs. The SSDs highlight strong effects on species richness due to high N concentrations in the tropical zone and the vulnerability of cold regions. Our study revealed the regional differences in sensitivities of freshwater ecosystems against N content in great spatial detail and can be used to assess more precisely and comprehensively nutrient-induced impacts in LCA.

Dairy pricing policy, production, and water quality: Application to the Chesapeake Bay watershed

AbstractThis study assesses the economic and water quality impacts of implementing a dairy pricing policy under Federal Milk Marketing Order system designed to alleviate milk prices plummet occurred at the beginning of pandemic. Using a 12‐region, positive mathematical programing model of livestock production in the Chesapeake Bay watershed, we find that pricing policy induces significant expansions in dairy sectors, generates higher level of total net revenue in regions having large base‐period dairy sectors. For water quality, we find that policy leads to an increase in nitrogen emissions but a decrease in phosphorus emissions for the livestock industry as a whole in most studied regions.

Performance enhancement and emissions reduction in a diesel engine using oleander and croton biodiesel doped with graphene nanoparticles

Biodiesel is considered a suitable substitute for petroleum diesel because it is renewable, environment-friendly, and has a low carbon footprint. However, its high density, high viscosity and low heating value prevents it from replacing petroleum diesel completely. This study investigates the performance and emission characteristics of a compression ignition engine operating on oleander and croton biodiesel doped with graphene nanoparticles. Five fuel samples are used, including diesel (D100), diesel - 80% blended with oleander and croton biodiesel - 20% (OCB20) and OCB20 dosed with graphene nanoparticles at mass fractions of 50 ppm (mg/L), 75 ppm (mg/L) and 100 ppm (mg/L), respectively. The chemical composition of biodiesel and graphene nanoparticles is analyzed using Fourier Transform Infrared (FTIR) spectroscopy while the morphology of the nanoparticles is analyzed using Scanning Electron Microscope (SEM). Engine tests reveal a significant improvement in brake thermal efficiency, especially at 75 ppm concentration which is 2.76% and 18.93% higher than diesel and OCB20, respectively, and a reduction in brake specific fuel consumption by 2.44% and 16.67% compared to diesel and OCB20, respectively. Carbon monoxide (CO) and unburnt hydrocarbon emissions (UHC) decreases for the 50 ppm sample, recording 8.58% and 21.65% reduction in CO and 52.2% and 50% in UHC compared to the diesel and OCB20, respectively. However, Oxides of Nitrogen (NOx) emissions increase. The results indicate that graphene nanoparticle-enhanced biodiesel can adequately substitute petroleum diesel, albeit with NOx reduction techniques.

Biodiesel with Fuel Additive: An Analysis of Engine Performance, Combustion and Emission Characteristics

Threats to the environment from exhaust emissions and global warming continue to generate more calls by most governments to end the use of fossil fuels and switch to green fuels. This study aims to examine one of the green fuels that is seeing rapid expansion, namely the biofuel known as biodiesel. Biodiesel is non-toxic, biodegradable, made from renewable sources and can reduce diesel engine exhaust emissions. Even though one of the technical benefits of biodiesel is its ability to be oxygenated in diesel engines without much hardware modifications; however, it has been unable to reduce exhaust tail emissions from diesel engines on its own. In this research, the impact of biodiesel mixed with oxygenated additive, diethyl ether, when subjected to performance, combustion, and emission tests in unmodified diesel engine at different speeds has been studied. Waste cooking oil was transesterified using methanol as a reagent and NaOH as catalyst. The biodiesel was blended manually at room temperature with diesel fuel and diethyl ether in different proportions while keeping the volume of diethyl ether constant at 10 %. The fuel blends (B10D90, B20D80, B30D70, B10A10D80, B20A10D70, and B30A10D60) were subjected to performance, combustion, and emission tests in a single-cylinder, four-stroke diesel engine coupled to a water-cooled Eddy current dynamometer and results obtained compared with diesel fuel. The results showed that all performance characteristics (brake power (BP), brake torque (BT), brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC)) improved with B10A10, which was found to closely resemble diesel. The peak cylinder pressures were higher for the blends, while the cylinder temperatures were comparable to those of diesel. The carbon monoxide (CO), carbon dioxide (CO2), hydrocarbon (HC) and oxides of nitrogen (NOx) emissions decreased more for all tested blends than for those of diesel at all engine speeds. Adding diethyl ether additives improved the physicochemical properties of biodiesel, making it a viable method for using biodiesel efficiently in diesel engines without modifying the engine. The study found that using green diesel fuel with a diethyl ether additive is a potential step toward improving air quality by lowering emissions from stationary, and transportation engines while maintaining optimal engine performance. As a result, using biodiesel-diesel fuels with the appropriate proportions of diethyl either additive has the potential to reduce greenhouse gas (GHG) emissions and ensure benign environment.

Multi-response optimization of the performance and emission characteristics of a diesel engine fueled with palm kernel oil methyl ester using TOPSIS-RSM hybrid approach

In the current experiment, various diesel and palm kernel oil methyl ester blends have been examined for performance and emission features using a diesel engine test rig. The optimization of operating factors is investigated by employing a hybrid Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) combined with Response Surface Methodology (RMS) methods. B20 blend and 100% load have been identified as the best fuel blend and operating range, respectively, for the biggest increase of brake thermal efficiency, reduction in brake specific fuel consumption, hydrocarbon, and oxides of nitrogen emissions when collated to other blends, based on the highest performance index value (0.809) at desirability level of 0.915.

Effects of changes in land use structure on nitrogen input in the Pingzhai Reservoir watershed, a karst mountain region

Optimizing land use composition to control nitrogen input into water bodies is one way to address surface source pollution in karst mountain regions. In this study, changes in land use, N sources, and spatial and temporal changes of N migration in the Pingzhai Reservoir watershed were evaluated from 2015 to 2021, and the relationship between land use composition and N input was elucidated. N was the main pollution in the water of the watershed; NO3− was the dominant form of N, and it did not react during migration. N came from soil, livestock manure or domestic sewage, and atmospheric deposition. Isolating the fractionation effects of source nitrogen is crucial to improve the accuracy of nitrogen and oxygen isotope traceability in the Pingzhai Reservoir. From 2015 to 2021, the grassland area in the Pingzhai Reservoir increased by 5.52%, the woodland area increased by 2.01%, the water area increased by 1.44%, the cropland decreased by 5.8%, unused land decreased by 3.18%, and construction land remained unchanged. Policies and reservoir construction were the main drivers of changes in land-use type in the catchment. Changes in land use structure affected nitrogen input patterns, with unused land having a highly significant positive correlation with inputs of NH3–N, NO2−, and TN, and construction land having a significant positive correlation with the input of NO2−. The inhibitory effect of forest and grassland on nitrogen input in the basin was offset by the promoting effect of cropland and construction land on nitrogen input, with unused land becoming a new focus area for nitrogen emissions due to a lack of environmental management. Modifying the area of different land use types in the watershed can effectively control nitrogen input to the watershed.

The Netherlands: Political Developments and Data in 2022

AbstractThe year 2022 was a period of contradictory developments in terms of political stability in the Netherlands. On the one hand, Mark Rutte became the longest‐serving Prime Minister in the country's history after celebrating his 12th year in office. On the other hand, the newly formed Rutte IV Cabinet was charged with steering the country through a tumultuous period, marked by soaring energy prices and inflation in the wake of the Russian invasion of Ukraine, large‐scale civil unrest in response to the government's plans to cut nitrogen emissions, and a political crisis over the housing of asylum seekers.