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In electrical power system engineering, the economic load dispatch (ELD) problem is a critical issue for fuel cost minimization. This ELD problem is often characterized by non-convexity and subject to multiple constraints. These constraints include valve-point loading effects (VPLEs), generator limits, emissions, and wind power integration. In this study, both emission constraints and wind power are incorporated into the ELD problem formulation, with the influence of wind power quantified using the incomplete gamma function (IGF). This study proposes a novel metaheuristic algorithm, the modified moth flame optimization (MMFO), which improves the traditional moth flame optimization (MFO) algorithm through an innovative flame selection process and adaptive adjustment of the spiral length. MMFO is a population-based technique that leverages the intelligent behavior of flames to effectively search for the global optimum, making it particularly suited for solving the ELD problem. To demonstrate the efficacy of MMFO in addressing the ELD problem, the algorithm is applied to four well-known test systems. Results show that MMFO outperforms other methods in terms of solution quality, speed, minimum fuel cost, and convergence rate. Furthermore, statistical analysis validates the reliability, robustness, and consistency of the proposed optimizer, as evidenced by the consistently low fitness values across iterations. [ABSTRACT FROM AUTHOR]

The paper presents experimental studies on the effect of co-combustion of aviation kerosene with hydrogen in the GTM400 turbojet engine on the change in the carbon footprint generated by the engine in relation to its standard operation without hydrogen in the fuel. This research is in line with current research and development trends carried out in the EU, linking them to the issues of the European Green Deal, the Fit for 55 directive and current environmental trends in aviation and energy. The main objective of the research was to check the effect of hydrogen co-combustion in a turbojet engine on the change of the carbon footprint, while a secondary objective was to verify the impact of higher exhaust gas temperatures generated by the new, high-calorific fuel on the secondary generation of nitrogen oxides (NOx), especially in the thermal mechanism, as an undesirable effect. The research shows that the co-combustion of hydrogen with aviation kerosene in a turbojet engine reduces the carbon footprint (reduction of CO2 maximum of 15% and CO emissions maximum of 24%), but also increases the emission of nitrogen oxides (NOx) maximum of 58%, including those generated in the thermal mechanism (significant increase in the temperature of exhaust gases), moreover, the increase in nitrogen oxide emissions is proportional to the amount of co-combusted hydrogen, which is directly related to the stoichiometry of the combustion process. The main conclusion of the research is that technologies for the combustion or co-combustion of hydrogen in turbojet engines require further research and development, mainly on the side of the use of excess exhaust gas temperature generated during combustion and methods of reducing secondary nitrogen oxides. [ABSTRACT FROM AUTHOR]

We investigate the terahertz (THz) scattering and emission properties of lunar regolith by modeling it as a random medium with rough top and bottom boundaries and a host medium situated beneath. The total scattering and emission arise from three sources: the rough boundaries, the volume, and the interactions between the boundaries and the volume. To account for these sources, we model their respective phase matrices and apply the matrix doubling approach to couple these phase matrices to compute the total emission. The model is then used to explore insights into lunar regolith scattering and emission processes. The simulations reveal that surface roughness is the primary contributor to total scattering, while dielectric contrasts between the volume and the boundaries dominate total emission. The THz emissivity is highly sensitive to the regolith dielectric constant, particularly its imaginary part, making it a promising alternative for identifying previously undetected water ice in the lunar polar regions. The THz emissivity model developed in this study can be readily applied to invert the surface parameters of lunar regolith using THz observations. [ABSTRACT FROM AUTHOR]

Microalgae are considered to be a promising and prospective source of lipids for the production of biocomponents for conventional liquid fuels. The available sources contain a lot of information about the cultivation of biomass and the amounts and composition of the resulting bio-oils. However, there is a lack of reliable and verified data on the impact of fuel blends based on microalgae biodiesel on the quality of the emitted exhaust gas. Therefore, the main objective of the study was to present the emission characteristics of a compression-ignition engine fuelled with a blend of diesel fuel and biodiesel produced from the lipids accumulated in the biomass of a heterotrophic culture of Schizochytrium sp. The final concentrations of microalgal biomass and lipids in the culture were 140.7 ± 13.9 g/L and 58.2 ± 1.1 g/L, respectively. The composition of fatty acids in the lipid fraction was dominated by decosahexaenoic acid (43.8 ± 2.8%) and palmitic acid (40.4 ± 2.8%). All parameters of the bio-oil met the requirements of the EN 14214 standard. It was found that the use of bio-components allowed lower concentrations of hydrocarbons in the exhaust gas, ranging between 33 ± 2 ppm and 38 ± 7 ppm, depending on the load level of the engine. For smoke opacity, lower emissions were found in the range of 50–100% engine load levels, where the observed content was between 23 ± 4% and 53 ± 8%. [ABSTRACT FROM AUTHOR]

Water in the engine/combustion chamber is not a novel phenomenon. Even humidity has a major effect on internal combustion engine emissions and can thus be considered the first invisibly present emission technology. With modern techniques, the problematic aspects of water, such as corrosion and lubrication issues, seem to disappear, and the benefits of water's effect in combustion may also be enhanced in the context of EURO 7. The current study examines the literature on the effects of water on diesel combustion in chronological sequence, focusing on changes over the last three decades. Then it analyzes and re-evaluates the water effect in the current technology and the forthcoming Euro 7 regulatory context, comparing the conclusions with current automotive applications and mobility trends, in order to show the possible benefits and prospective research avenues in this sector. Techniques introducing water to combustion could be a major approach in terms of the EURO 7 retrofit mandate, as well as a feasible technique for concurrent nitrogen oxides and particulate reduction. [ABSTRACT FROM AUTHOR]

The use of biodiesel as an alternative to conventional diesel fuels has gained significant attention due to its potential for reducing greenhouse gas emissions and improving energy sustainability. This study explores the impact of TiO2 nanoparticles on the emission characteristics and combustion efficiency of biodiesel blends in compression ignition (CI) engines. The fuels analyzed include diesel, SB20 (soybean biodiesel), SB20 + 50 TiO2 ppm, SB20 + 75 TiO2 ppm, PB20 (palm biodiesel), PB20 + 50 TiO2 ppm, and PB20 + 75 TiO2 ppm. Experiments were conducted under a consistent load of 50% across engine speeds ranging from 1000 to 1800 RPM. While TiO2 nanoparticles have been widely recognized for their ability to enhance biodiesel properties, limited research exists on their specific effects on soybean and palm biofuels. This study addresses these gaps by providing a comprehensive analysis of emissions, including NOX, CO, CO2, and HC, as well as exhaust gas temperature (EGT), across various engine speeds and nanoparticle concentrations. The results demonstrate that TiO2 nanoparticles lead to a reduction in CO emissions by up to 30% and a reduction in HC emissions by 21.5% at higher concentrations and engine speeds. However, this improvement in combustion efficiency is accompanied by a 15% increase in CO2 emissions, indicating more complete fuel oxidation. Additionally, NOX emissions, which typically increase with engine speed, were mitigated by 20% with the addition of TiO2 nanoparticles. Exhaust gas temperatures (EGTs) were also lowered, indicating enhanced combustion stability. These findings highlight the potential of TiO2 nanoparticles to optimize biodiesel blends for improved environmental performance in CI engines. [ABSTRACT FROM AUTHOR]

In response to increasing environmental demands, modeling emissions from older vehicles presents a significant challenge. This paper introduces an innovative methodology that takes advantage of advanced AI and machine learning techniques to develop precise emission models for older vehicles. This study analyzed data from road tests and the OBDII diagnostic interface, focusing on CO2, CO, THC, and NOx emissions under both cold and warm engine conditions. The key results showed that random forest regression provided the best predictions for THC in a cold engine (R2: 0.76), while polynomial regression excelled for CO2 (R2: 0.93). For warm engines, polynomial regression performed best for CO2 (R2: 0.95), and gradient boosting delivered results for THC (R2: 0.66). Although prediction accuracy varied by emission compound and engine state, the models consistently demonstrated high precision, offering a robust tool for managing emissions from aging vehicle fleets. These models offer valuable information for transportation policy and pollution reduction strategies, particularly in urban areas. [ABSTRACT FROM AUTHOR]

Heated tobacco products (HTPs) are newly developed nicotine delivery systems via the inhalation of mainstream aerosols generated during the heating of tobacco leaf materials. Previous studies have shown that the amount of chemicals generated is much lower than that generated by conventional combustible cigarettes. However, little attention has been paid to formate, a conjugated base of formic acid with potentially toxic effects on human health. This study aims to understand the actual emission levels and behaviour of formate in mainstream aerosols produced by commercially available HTP devices in Japan. Aerosols were generated from four types of devices with regular and menthol-type flavours using a vaping machine following the CRM 81 puffing protocol. Formate was tapped in 5 mM sodium carbonate solution and subsequently analysed using ion chromatography. The results showed that the total emission amount of formate ranged from 0.0027 ± 0.0031 to 0.27 ± 0.055 mg L−1, varying with heating temperature and flavour type. Moreover, the majority of formate existed in a particulate form due to the weak-basic property of the aerosol, and the formate emission level was much greater than the workplace exposure limit for the direct inhalation of mainstream aerosols. The formate in the mainstream aerosol can be considered a health concern, when using "high-temperature type" HTPs over a long period. [ABSTRACT FROM AUTHOR]

In the era of decarbonization driven by environmental concerns and stimulated by legislative measures such as Fit for 55, the industry and transportation sectors are increasingly replacing petroleum-based fuels with those derived from renewable sources. For many years, the share of these fuels in blends used to power compression ignition engines has been growing. The primary advantage of this fuel technology is the reduction of GHG emissions while maintaining comparable engine performance. However, these fuel blends also have drawbacks, including limited ability to form stable mixtures or the requirement for chemical stabilizers. The stability of these mixtures varies depending on the type of alcohol used, which limits the applicability of such fuels. This study focuses on evaluating the impact of eight types of alcohol fuels, including short-chain (methanol, ethanol, propanol) and long-chain alcohols (butanol, pentanol, hexanol, heptanol, and octanol), on the most critical operational parameters of an industrial engine and exhaust emissions. The engines being compared operated at a constant speed and under a constant load, either maximum or close to maximum. The study also evaluated the effect of alcohol content in the mixture on combustion process parameters such as peak cylinder pressure and heat release, which are the basis for parameterizing the engine's combustion process. Determining ignition delay and combustion duration is fundamental for optimizing the engine's thermal cycle. As the research results show, both the type of alcohol and its concentration in the mixture influence these parameters. Another parameter important from a usability perspective is engine stability, which was also considered. Engine performance evaluation also includes assessing emissions, particularly the impact of alcohol content on NOx and soot emissions. Based on the analysis, it can be concluded that adding alcohol fuel to diesel in a CI engine increases ignition delay (up to 57%), pmax (by approximately 15–20%), HRRmax (by approximately 80%), and PPRmax (by approximately 70%). Most studies indicate a reduction in combustion duration with increasing alcohol content (by up to 50%). For simple alcohols, an increase in thermal efficiency (by approximately 15%) was observed, whereas for complex alcohols, a decrease (by approximately 10%) was noted. The addition of alcohol to diesel slightly worsens the stability of the CI engine. Most studies pointed to the positive impact of adding alcohol fuel to diesel on NOx emissions from the compression ignition engine, with the most significant reductions reaching approximately 50%. Increasing the alcohol fuel content in the diesel blend significantly reduced soot emissions from the CI engine (by up to approximately 90%). [ABSTRACT FROM AUTHOR]

In order to reduce global warming, new energy fuels that use waste biomass to replace traditional coal are rapidly developing. The main purpose of this study is to investigate the feasibility behavior of different biomass materials such as spent coffee grounds (SCGs) and spent tea grounds (STGs) as fuel during combustion and their impact on the environment. This study involves using fuel shaping and co-firing methods to increase the fuel calorific value and reduce the emissions of pollutants, such as NOX and SO2, and greenhouse gas CO2. The produced gas content was analyzed using the HORIBA (PG-250) laboratory combustion apparatus. The results indicate that, among the measured formed particles, SCG:STG = 8:2, 6:4, and 4:6 had the lowest post-combustion pollutant gas emissions. Compared to using only waste coffee grounds as fuel, the NOx emissions were reduced from 166 ppm to 102 ppm, the CO emissions were reduced from 22 ppm to 12 ppm, and the CO2 emissions were reduced from 629 ppm to 323 ppm. In addition, the emission of SO2, the main component of acid rain, was reduced by 20 times compared to the combustion of traditional fuels. The SO2 emission of five different proportions of biomass fuels was 5 ppm, which is much lower than that of traditional coal fuels. Therefore, SCG and STG mixed fuels can replace coal as fuel while reducing harmful gasses. [ABSTRACT FROM AUTHOR]

Methane is a powerful greenhouse gas with a 25 times higher 100-year warming potential than carbon dioxide and is a target for mitigation to achieve climate goals. To control and curb methane emissions, estimates are required from the sources and sectors which are typically generated using bottom-up methods. However, recent studies have shown that national and international bottom-up approaches can significantly underestimate emissions. In this study, we present three bottom-up approaches used to estimate methane emissions from all emission sectors in the Denver-Julesburg basin, CO, USA. Our data show emissions generated from all three methods are lower than historic measurements. A Tier 1/2 approach using IPCC emission factors estimated 2022 methane emissions of 358 Gg (0.8% of produced methane lost by the energy sector), while a Tier 3 EPA-based approach estimated emissions of 269 Gg (0.2%). Using emission factors informed by contemporary and region-specific measurement studies, emissions of 212 Gg (0.2%) were calculated. The largest difference in emissions estimates were a result of using the Mechanistic Air Emissions Simulator (MAES) for the production and transport of oil and gas in the DJ basin. The MAES accounts for changes to regulatory practice in the DJ basin, which include comprehensive requirements for compressors, pneumatics, equipment leaks, and fugitive emissions, which were implemented to reduce emissions starting in 2014. The measurement revealed that normalized gas loss is predicted to have been reduced by a factor of 20 when compared to 10-year-old normalization loss measurements and a factor of 10 less than a nearby oil and production area (Delaware basin, TX); however, we suggest that more measurements should be made to ensure that the long-tail emission distribution has been captured by the modeling. This study suggests that regulations implemented by the Colorado Department of Public Health and Environment could have reduced emissions by a factor of 20, but contemporary regional measurements should be made to ensure these bottom-up calculations are realistic. [ABSTRACT FROM AUTHOR]

Despite the extensive research on biodiesels, further investigation is warranted on the impact of compression ratios on emissions and engine performance. This study addresses this gap by evaluating the effects of increasing the engine's compression ratio on engine performance metrics—brake-specific fuel consumption (BSFC), power, torque, and exhaust gas temperature—and emissions—unburnt hydrocarbons (HCs), carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxides (NOx), and oxygen (O2)—when fueled with a 20% blend of waste cooking oil biodiesel (WCB20) and petroleum diesel (PD) under various operating conditions. The viscosity of the prepared fuels was measured at 25 °C and 40 °C. Experiments were conducted on a single-cylinder diesel engine under wide-open throttle conditions at three different speeds (1400 rpm, 2000 rpm, and 2600 rpm) and two compression ratios (16:1 and 18:1). The results revealed that at a lower compression ratio, both WCB20 and petroleum diesel exhibited reduced BSFC compared to higher compression ratios. However, increasing the compression ratio from 16:1 to 18:1 significantly decreased HC emissions but increased CO2 and NOx emissions. Engine power increased with engine speed for both fuels and compression ratios, with WCB20 initially producing less power than diesel but surpassing it at higher compression ratios. WCB20 demonstrated improved combustion quality with lower unburnt hydrocarbons and carbon monoxide emissions due to its higher oxygen content, promoting complete combustion. This study provides critical insights into optimizing engine performance and emission characteristics by manipulating compression ratios and utilizing biodiesel blends, paving the way for more efficient and environmentally friendly diesel engine operations. [ABSTRACT FROM AUTHOR]

Natural gas (NG) is favored for transportation due to its availability and lower CO2 emissions than fossil fuels, despite drawbacks like poor lean combustion ability and slow burning. According to a few recent studies, using hydrogen (H2) alongside NG and diesel in Tri-fuel mode addresses these drawbacks while enhancing efficiency and reducing emissions, making it a promising option for diesel engines. Due to the importance and novelty of this, the continuation of ongoing research, and insufficient literature studies on HNG–diesel engine emissions that are considered helpful to researchers, this research has been conducted. This review summarizes the recent research on the HNG–diesel Tri-fuel engines utilizing hydrogen-enriched natural gas (HNG). The research methodology involved summarizing the effect of engine design, operating conditions, fuel mixing ratios and supplying techniques on the CO, CO2, NOx and HC emissions separately. Previous studies show that using natural gas with diesel increases CO and HC emissions while decreasing NOx and CO2 compared to pure diesel. However, using hydrogen with diesel reduces CO, CO2, and HC emissions but increases NOx. On the other hand, HNG–diesel fuel mode effectively mitigates the disadvantages of using these fuels separately, resulting in decreased emissions of CO, CO2, HC, and NOx. The inclusion of hydrogen improves combustion efficiency, reduces ignition delay, and enhances heat release and in-cylinder pressure. Additionally, operational parameters such as engine power, speed, load, air–fuel ratio, compression ratio, and injection parameters directly affect emissions in HNG–diesel Tri-fuel engines. Overall, the Tri-fuel approach offers promising emissions benefits compared to using natural gas or hydrogen separately as dual-fuels. [ABSTRACT FROM AUTHOR]

A study was conducted to measure aerosol particles emitted from laboratory coats (lab coats) under vibration, comparing them with a suit and a shirt. This study focused on particles ranging from 0.3 μm to >10 μm. Experimental results showed that lab coat vibration increased particles >5 μm while reducing submicron particles. The lab coat (old and used) exhibited greater particle concentration variations under vibration compared to those using the new lab coat or the shirt. Contrastingly, the suit under vibration did not significantly affect particle concentrations. These findings highlight the impact of lab coat vibration on aerosol particle concentrations in the surrounding air, which is important for work environments. [ABSTRACT FROM AUTHOR]

Fuelled engines serve as prime movers in low-, medium-, and heavy-duty applications with high thermal diesel efficiency and good fuel economy compared to their counterpart, spark ignition engines. In recent years, diesel engines have undergone a multitude of developments, however, diesel engines release high levels of NOx, smoke, carbon monoxide [CO], and hydrocarbon [HC] emissions. Due to the exponential growth in fleet population, there is a severe burden caused by petroleum-derived fuels. To tackle both fuel and pollution issues, the research community has developed strategies to use economically viable alternative fuels. The present experimental investigations deal with the use of blends of biodiesel prepared from waste plastic oil [P] and petro-diesel [D], and, to improve its performance, hydrogen [H] is added in small amounts. Further, advanced injection timings have been adopted [17.5° to 25.5° b TDC (before top dead centre)] to study their effect on harmful emissions. Hydrogen energy shares vary from 5 to 15%, maintaining a biodiesel proportion of 20%, and the remaining is petro-diesel. Thus, the adopted blends are DP20 ((diesel fuel (80%) and waste plastic biofuel (20%)), DP20H5 (DP20 (95%) and hydrogen (5%)), DP20H10 (DP20 (90%) and hydrogen (10%)), and DP20H15 (DP20 (85%) and hydrogen (15%)). The experiments were conducted at constant speeds with a rated injection pressure of 220 bar and a rated compression ratio of 18. The increase in the share of hydrogen led to a considerable improvement in the performance. Under full load conditions, with advanced injection timings, the brake-specific fuel consumption had significantly decreased and NOx emissions increased. [ABSTRACT FROM AUTHOR]

This paper includes a discussion of the results of tests concerning changes in the thermal and emission parameters of a boiler fuelled with wood biomass under the influence of air gradation in the combustion process. The test results ensure insight into the combustion process of wood biomass with air gradation, which significantly affected the operation of the device, increasing the mass concentration of the emitted nitrogen oxide (NOx) by combustion temperature lowering, especially in the afterburning zone. The authors observed an increase in the emission of particulate matter (PM) and carbon monoxide (CO) related to the change in the combustion process stoichiometry. The tests were carried out with the use of a heating boiler equipped with an automatic pellet burner. Apart from the mass concentration measurement of the pollution emitted, the tests focused on the measurements of temperature and oxygen levels in the flue gas. The objective of the tests was to confirm the applicability of the air gradation techniques in biomass combustion in order to reduce the emission of harmful substances from heating boilers, which is a technique that has recently been used in this group of devices. The test results obtained confirm the necessity for reorganising the technical systems of the currently used pellet burners and implementing further empirical tests. [ABSTRACT FROM AUTHOR]

The CO2 emission activity of xylotrophic fungi responding to an increase in temperature in the range of 10–30 °C with pure dikaryotic cultures of Fomes fomentarius s. str., F. inzengae, Fomitopsis betulina, F. pinicola, and Phellinus igniarius was analyzed. Emission activity was assessed by the difference in CO2 concentration in 0.5 L exposure chambers with Petri dishes with mycelium growing on agar at the beginning of exposure and an hour later using a Gasmet DX-4030 FTIR spectrometer (Gasmet Technologies Oy, Finland), error measurements ±50 ppm. Specific (μg CO2/cm2/h) and total (μg CO2/h) emission activity and its relationship with temperature and size (area) of the mycelium were assessed. It is shown that in the range of 10–30 °C, the specific and total CO2 emission activity of the mycelium is closely and positively related to temperature. Specific emission, which is an indicator of the respiratory activity of the mycelium, does not depend on its size; its only driver is temperature, the relationship with which is linear: an increase in temperature by 10 °C causes an increase in the specific emission activity of the mycelium by 1.7 times. The total CO2 emission activity, which is an indicator of the total amount of CO2 emitted, is directly proportional to the specific emission activity and the size of the mycelium. In the range of 10–30 °C, an increase in temperature causes an almost equal increase in both the specific emission activity of the mycelium (Q10 1.7) and its growth (Q10 1.5) and causes an exponential increase in the total emission of CO2. This must be taken into account when predicting CO2 emissions from woody debris under climate change, as it could potentially contribute to accelerating climate change. [ABSTRACT FROM AUTHOR]

This study analyzes the combustion of pellets and briquettes made of plant biomass in low-power heating devices powered periodically with fuel being placed on the grate, as well as after modification using an automatic fuel feeding system in the gutter burner. The use of herbaceous biomass in the form of pellets in low-power heating devices with automatic fuel feeding and combustion in a gutter burner is not widely promoted and popular. Therefore, this study used four types of herbaceous waste biomass (wheat straw, rye straw, oat straw and hay) and one type of woody waste biomass (birch sawdust) for testing. The basic chemical characteristics were determined for the raw materials. After appropriate preparation, the selected starting materials were subjected to briquetting and pelleting processes. Selected physical properties were also determined for the obtained biofuels. Biofuels made from birch sawdust had the lowest heat value (16.34 MJ·kg−1), although biofuels made from wheat, rye and hay straw had a slightly lower calorific value, respectively: 16.29; 16.28 and 16.26 MJ·kg−1. However, the calorific value of oat straw biofuels was only 15.47 MJ kg−1. Moreover, the ash content for herbaceous biomass was 2–4 times higher than for woody biomass. Similar differences between herbaceous and woody biomass were also observed for the nitrogen and sulfur content. To burn the prepared biofuels, a domestic grate-fired biomass boiler was used, periodically fed with portions of fuel in the form of pellets or briquettes (type A tests), which was then modified with a gutter burner enabling the automatic feeding of fuel in the form of pellets (type B tests). During the combustion tests with simultaneous timing, the concentration of CO2, CO, NO and SO2 in the exhaust gases was examined and the temperature of the supplied air and exhaust gases was measured. The stack loss (qA), combustion efficiency index (CEI) and toxicity index (TI) were also calculated. The research shows that the use of automatic fuel feeding stabilizes the combustion process. The combustion process is balanced between herbaceous and woody biomass biofuels. Disparities in CO2, CO and Tgas emissions are decreasing. However, during type B tests, an increase in NO emissions is observed. At the same time, the research conducted indicates that the combustion of herbaceous biomass pellets with their automatic feeding into the combustion chamber is characterized by an increase in combustion efficiency, indicating that when the combustion process is automated, they are a good replacement for wood biofuels—both pellets and briquettes. [ABSTRACT FROM AUTHOR]

Creating accurate emission models capable of capturing the variability and dynamics of modern propulsion systems is crucial for future mobility planning. This paper presents a methodology for creating THC and NOx emission models for vehicles equipped with start–stop technology. A key aspect of this endeavor is to find techniques that accurately replicate the engine's stop stages when there are no emissions. To this end, several machine learning techniques were tested using the Python programming language. Random forest and gradient boosting methods demonstrated the best predictive capabilities for THC and NOx emissions, achieving R2 scores of approximately 0.9 for engine emissions. Additionally, recommendations for effective modeling of such emissions from vehicles are presented in the paper. [ABSTRACT FROM AUTHOR]

The treatment of sewage sludge has become a global concern. Large amounts of sewage sludge can be disposed of by burning coal-mixed sludge. Thermogravimetric analysis and lab-scale combustion experiments in a drop tube furnace were utilized to study the combustion characteristics, pollutant emissions, and heavy metal migration during the co-combustion of coal and sewage sludge. The results showed that the blended fuels with a sewage sludge content less than 10 weight percent exhibited coal-like combustion characteristics. Additionally, the additional sewage sludge favored the ignition performance of blended fuels. When sewage sludge was added, the SO2 emissions rose to 76 mg/Nm3 under the 10% sludge condition—nearly three times higher than that of coal alone. While NOx emissions stayed mostly unchanged, HCl and HF emissions were very low. Meanwhile, Cr, Cu, and Ni migrated to the bottom ash, and their concentrations were all reduced with an increase in sewage sludge. Pb, Cd, Cr, Cu, Ni, and Hg migrated to the flue gas, mostly in the form of gaseous components. The results provide crucial information in the co-combustion of sewage sludge and coal, with implications in the development and improvement of large-scale, harmless, and resource-recovering techniques for waste sludge. [ABSTRACT FROM AUTHOR]

This article presents the possibility of improving combustion using the effect of releasing hydrogen from a solution with nucleation of gas bubbles. This concept consists in dissolving hydrogen in diesel fuel until the equilibrium state of the solution is reached. At a later stage, the phenomenon is reversed, and this gas is released from the solution during its injection into the combustion chamber with a strong swirl. A characteristic feature of the solution is that when lowering the pressure (opening the atomizers), there is a decrease in the equilibrium thermodynamic potential, which results in the excess, dissolved hydrogen being released spontaneously, and this process is of a volumetric nature. This article is a continuation of the work carried out at Poznan University of Technology on the development of this concept. This article presents the results of tests for the impact of hydrogen dissolved in diesel fuel on the combustion process within a turbulent-flow environment. The tests were conducted in the combustion chamber of an engine equipped with a toroidal combustion chamber and direct injection. During the tests, the following factors were measured: the main indicators of motor operation, emission of hydrocarbons, carbon monoxide, nitrogen oxides, and particulate matters. [ABSTRACT FROM AUTHOR]

Diesel engine combustion is dependent mainly on the fuel injection characteristics, particularly the injection pressure and rate, which directly affect the engine efficiency and emissions. Herein, an electrically controlled supercharger is added to a traditional high-pressure common rail system to form an ultrahigh-pressure common rail system. Then, the variations in the spray, combustion, and emission characteristics of a diesel engine with a variable fuel injection rate are analyzed. Moreover, a simulation model for a diesel engine combustion chamber is built and verified by experimental results for numerical analysis. The results reveal that the injection rate can be flexibly adjusted via regulation when the solenoid valves are opened on the electrically controlled supercharger. Specifically, (1) the boot-shaped injection rate has greater potential than the traditional rectangular injection rate in terms of combustion and emission; (2) the main injection advance angle at the boot-shaped injection rate can be properly increased to improve combustion; and (3) the pilot injection quantity and advance angle are strongly coupled with the boot-shaped injection rate, potentially enhancing the mixing efficiency of fuel and air in the cylinder to achieve favorable emission results. This paper provides good guidance for the reliable design and optimization of noble-metal-based diesel engines. [ABSTRACT FROM AUTHOR]

Meat quality determination is now more vital than ever, with an ever-increasing demand for meat, especially with a greater desire for high-quality beef. Many existing qualitative methods currently used for meat quality assessment are strenuous, time-consuming, and subjective. The quantitative techniques employed are time-consuming, destructive, and expensive. In the search for a quantitative, rapid, and non-destructive method of determining meat quality, the use of autofluorescence has been employed and has demonstrated its capabilities to characterise meat grades by identifying biochemical features such as the intramuscular fat and tryptophan content through the excitation of meat samples and the collection and analysis of the emission data. Despite its success, the method remains expensive and inaccessible, thus preventing it from being translated into small-scale industry applications. This study will detail the process taken to design and construct a low-cost, miniature prototype device that could successfully distinguish between varying meat grades using autofluorescence imaging and machine learning techniques. [ABSTRACT FROM AUTHOR]

In response to increasingly stringent global environmental policies, this study addresses the pressing need for accurate prediction models of CO2 emissions from vehicles powered by alternative fuels, such as compressed natural gas (CNG). Through experimentation and modelling, one of the pioneering CO2 emission models specifically designed for CNG-powered vehicles is presented. Using data from chassis dynamometer tests and road assessments conducted with a portable emission measurement system (PEMS), the study employs the XGBoost technique within the Optuna Python programming language framework. The validation of the models produced impressive results, with R2 values of 0.9 and 0.7 and RMSE values of 0.49 and 0.71 for chassis dynamometer and road test data, respectively. The robustness and precision of these models offer invaluable information to transportation decision-makers engaged in environmental analyses and policymaking for urban areas, facilitating informed strategies to mitigate vehicular emissions and foster sustainable transportation practices. [ABSTRACT FROM AUTHOR]

Agricultural production, including animal husbandry, is associated with greenhouse gas (GHG) emissions, which have a negative impact on the environment. The purpose of this study was to determine methane and nitrous oxide emissions at the level of individual farms and to identify differences in emissions by type of production. Analyses were conducted using data from the FADN agricultural accounting system, covering the farms in Poland engaged in dairy production and the breeding of other grazing livestock for the period from 2012 to 2021. The relationships and trends of the indicators during the study period were also analyzed. The statistical analysis confirmed the relationship between greenhouse gas emissions and economic performance. In the case of dairy farms, the emissions averaged 137.09 kg·ha−1 of methane and 94.05 kg·ha−1 of nitrous oxide, which were found to increase as the net-added value and farm income increased. The results of the presented research highlight the existence of a link between economic goals and GHG emissions, which is an important contribution to the development of mitigation strategies in livestock production. [ABSTRACT FROM AUTHOR]

In this paper, in order to improve the fuel economy of the actual application of the engine under multi-operating conditions, an experimental study is carried out on a turbo-charged direct-injection engine based on different pre-chamber structures. The engine used for the study is a four-cylinder turbo-charged direct-injection gasoline engine with different structures of pre-chamber spark plugs. The operating conditions in this study include load characteristics at 2000 r/min and characteristic loads at different speeds, including 3000 r/min, 3200 r/min, and 3600 r/min. With stable BMEP or fully open throttle and pedal, the experiment was conducted by the spark angle scanning method to collect data of engine power, economy, and emission under each condition. It was found that the pre-chamber structure has a direct effect on engine performance, with a clear load demarcation line for its effect. Under the WOT condition, the power of pre-chamber ignition is 1.6% higher than that of conventional spark plugs; at the low load of 2 bar, the economy of pre-chamber ignition is degraded by 6%; at the medium load of 8 bar, the economy of the two is comparable; at the large load of 16 bar, the fuel economy proves advantageous. Compared with conventional spark plugs, the pre-chamber spark angle can be advanced by 2~3 °CA, and the pre-chamber ignition with separate ground electrodes is highly reliable. The emission levels of the pre-chamber spark plugs and conventional spark plugs are comparable at all loads. [ABSTRACT FROM AUTHOR]

Intrinsically fluorescent liquid crystals are highly sought after for a variety of applications. Most of the measurements of photo-physical properties of liquid crystals are made in dilute solutions, which is mainly due to the relative ease of both these measurements and the interpretation of data. The fluorescence spectra depend on a number of parameters including the concentration in liquid crystal solutions, the device geometry, and the mesophase in which the spectra have been measured. Working with neat, or concentrated, liquid crystal samples adds experimental complexities such as the inner filter effect (IFE), which affects the collection of data, interpretation of the results, and accuracy of the conclusions. In this paper, we present a systematic study of the photo-physical properties of both a model reference material, Nile red, and a nematic liquid crystal, 4-cyano-4′-pentylbiphenyl (5CB). The influence on the emission spectra of an increasing solute concentration is investigated and discussed. Moreover, a detailed investigation of the influence of the used device geometry, as well as the choice of appropriate data fitting methodologies, are presented. [ABSTRACT FROM AUTHOR]

The predominance of petroleum-based fuels is lessened by the preference for biodiesel as an alternative. However, one of the adverse effects arising from the use of biodiesel is the formation of waste heat. The novel aspect of this study proposes a sustainable solution that will decelerate global warming by recovering waste heat through a new exhaust design equipped with thermoelectric generators. The study obtained test fuels by blending vegetable-derived biodiesel in five different volumetric ratios (0, 10%, 20%, 50%, and 100%). The experiments were carried out at three different constant engine speeds (1000, 1250, and 1500 RPM) and five different engine loads (25%, 50%, 75%, and 100%) on a single-cylinder diesel engine. At the end of the experiment, the combustion characteristics, engine performance, exhaust emissions, waste heat values, and electrical energy gained from the thermoelectric system of biodiesel blend fuels compared to diesel were evaluated. Specific fuel consumption, effective efficiency, exhaust gas temperatures, exhaust emissions, and electrical power generation with TEG in the diesel engine were evaluated, focusing on the different biodiesel blend ratios, engine load, and engine speeds. [ABSTRACT FROM AUTHOR]

The dynamically growing sustainable aviation fuel (SAF) industry and the implemented European policy create the need for conducting research on the actual benefits of using alternative fuels in aviation. The aim of this research was to assess the impact of HEFA (hydroprocessed esters and fatty acids) fuel on the particulate matter emission indicators of an aircraft engine. This article presents the results of the measurements of particle emissions from a jet engine fueled by a blend of aviation kerosene and HEFA fuel (with HEFA content at 5%, 20%, and 30% by volume). A positive effect of HEFA on both the number and mass indices of particles was observed. The use of SAF fuel led to a reduction in the particulate number index by 90% and the particulate mass index by 75%. The Particle Number Emission Index (EIN) for an engine fueled with Jet A-1 exhibited values ranging from 5.23 × 1016 to 1.33 × 1017 particles per kilogram. The use of HEFA fuel (30% content) allowed for a reduction in the EIN to the range of 2.83 × 1015 to 1.04 × 1016 particles per kilogram. A detailed analysis of particle size distribution (PSD) for both the number and volume of particles was conducted. It was noted that neither the fuel composition nor the engine operating parameters significantly affected the shape of the PSD, but the use of HEFA fuel distinctly reduced the values of the number-based PSD. It was observed that the volume-based PSD had a bimodal shape, indicating a significant contribution of particles larger than 100 nm, forming the so-called soot mode. Our findings suggest that even a small amount of HEFA fuel yields satisfactory results in reducing particulate matter emissions. [ABSTRACT FROM AUTHOR]

As an important irritant trace gas in the atmosphere, ammonia (NH3) significantly impacts human health and environment. Bottom-up emission inventories are widely used to estimate ammonia emissions and their geographical distributions over China. However, high uncertainties are still associated with emission inventories due to inaccurate emission factors used. The Differential Evolution (DE) algorithm is a population-based stochastic optimization algorithm used to solve complicated optimization problems. We quantify NH3 emissions and lifetime from Infrared Atmospheric Sounding Interferometer (IASI) NH3 observations together with MERRA-2 wind fields based on the DE algorithm. Two inland cities, Urumchi and Golmud in China, are chosen to study of the NH3 emissions based on the distributions of NH3 total columns and wind fields. The NH3 emissions rate estimated is about 5.84 × 10−11 and 4.19 × 10−11 kg·m−2s−1 in Urumchi and in the Golmud area from May to September from 2008 to 2023, respectively. The lifetime of NH3 estimated in the two areas is 4.31 and 9.19 h, respectively. We compare the NH3 emissions and lifetime estimated in this study with the values in other studies, and the results show the reliability of the method used. This work is one of few quantitative studies of NH3 emissions from cities using satellite observations in China. [ABSTRACT FROM AUTHOR]

Large city-scale coal-fired combined heat and power (CHP) plants are one of the main contributors to greenhouse gas emissions. The motivation is to find a way to decrease the contributions in the most feasible way possible. The importance of this study is that it presents a methodology for comparing scenarios from both environmental and economic points of view. The scenarios aim to enhance the environmental performance of combustion flue gas-treatment units. The scenarios include installing an advanced electrostatic precipitator (ESP), a hybrid system comprising ESP and a bag filter, a combined cyclone and baghouse filter, a hybrid baghouse filter with novel electrostatic tissue, a wet flue gas desulfurization (WFGD) scrubber, a WFGD with (NH4)2SO4 technology, and fuel conversion (incl. biomass). Each of the scenarios is evaluated according to (a) primary energy consumption, (b) capital (CapEx) and operational (OpEx) costs, and (c) the obtained environmental effect (decreasing emissions of particulate matter (PM), CO2, SO2, and NOx). Adopting biomass waste decreases CO2 emissions by 50%. PM from the coal-fired boiler with particle filtration is lower compared to biomass but is two times higher than that from natural gas. Using advanced filters for a CHP plant decreases total emissions and PM by 2100–2800%. The largest effect on air quality is achieved by filtration and WFGD, with emissions decreasing by 43%. Primary energy consumption is maximal in fuel conversion and ESP scenarios. The conversion to limestone-based WFGD or the installation of a hybrid filter separately are the most viable options, totaling EUR 14.2 billion of CapEx. However, combining several technologies is essential to increase the quality of flue gas treatment. [ABSTRACT FROM AUTHOR]

The article aims to analyze the impact of green investments and the development of renewable energy on greenhouse gas emissions based on 223 countries in 2011–2021. The information base is the International Renewable Energy Agency, Our World in Data, Climate Policy Initiative, and FTSE Russell. Correlation analysis was used to check the data multicollinearity, multivariate regression analysis with stepwise variable entry—to formalize functional relationships. All variables characterizing the dynamics of green investments and the development of alternative energy, the number of annual investments in off-grid renewable energy has the largest impact on the amount of CO2 and N2O. Thus, an annual investment increase of USD 1 million leads to a CO2 emission increase of 4.5 kt and an N2O emission increase of 0.272 kt. Simultaneously, the green economy's market capitalization level has the largest impact on the amount of CH4. In this case, a capitalization increases of USD 1 trillion leads to a CH4 emission increase of 129.53 kt. The dynamics of renewable energy development have a statistically significant effect on only one of the three studied greenhouse gases—CO2 emissions. Here, 1 MW growth of an absolute increase in off-grid renewable energy capacity leads to a 1171.17 kt reduction of CO2 emissions. Checking input data for lags confirmed a time lag of one year between the level of green investments and the level of greenhouse gas emissions. That is, the impact of green investments on the level of greenhouse gas emissions is delayed by one year. The results of regression models taking into account lags confirmed that an increase in the level of green investments has a positive effect on reducing the level of greenhouse gas emissions (an increase in off-grid renewable energy annual investments of USD 1 million leads to a decrease in CO2 of 1.18 kt and N2O of 1.102 kt; the increase in green economy market capitalization of USD 1 trillion leads to a decrease in CH4 emissions of 0.64 kt). [ABSTRACT FROM AUTHOR]

Organic light-emitting diodes (OLEDs) have garnered considerable attention in academic and industrial circles due to their potential applications in flat-panel displays and solid-state lighting technologies, leveraging the advantages offered by organic electroactive derivatives over their inorganic counterparts. The thin and flexible design of OLEDs enables the development of innovative lighting solutions, facilitating the creation of customizable and contoured lighting panels. Among the diverse electroactive components employed in the molecular design of OLED materials, the benzophenone core has attracted much attention as a fragment for the synthesis of organic semiconductors. On the other hand, benzophenone also functions as a classical phosphor with high intersystem crossing efficiency. This characteristic makes it a compelling candidate for effective reverse intersystem crossing, with potential in leading to the development of thermally activated delayed fluorescent (TADF) emitters. These emitting materials witnessed a pronounced interest in recent years due to their incorporation in metal-free electroactive frameworks and the capability to convert triplet excitons into emissive singlet excitons through reverse intersystem crossing (RISC), consequently achieving exceptionally high external quantum efficiencies (EQEs). This review article comprehensively overviews the synthetic pathways, thermal characteristics, electrochemical behaviour, and photophysical properties of derivatives based on benzophenone. Furthermore, we explore their applications in OLED devices, both as host materials and emitters, shedding light on the promising opportunities that benzophenone-based compounds present in advancing OLED technology. [ABSTRACT FROM AUTHOR]

The unit commitment (UC) problem aims to reduce the power generation costs of power generation units in the traditional power system structure. However, under the current arrangement, the problem of cutting the cost of producing electricity has turned into an opportunity to boost power generation units' profits. Emission concerns are now given considerable weight when talking about the performance planning of power generation units, in addition to economic objectives. Because emissions are viewed as a limitation rather than an objective function in the majority of recent research that has been published in the literature, this paper solves the multi-objective profit-based unit commitment (PBUC) problem while taking into account energy storage systems (ESSs) and renewable energy systems (RESs) in the presence of uncertainty sources, such as demand and energy prices, in order to minimize generated emissions and maximize profits by power generation units in the fiercely competitive energy market. Owing to the intricacy of the optimization problem, a novel mutation-based modified version of the shuffled frog leaping algorithm (SFLA) is suggested as a way to get around the PBUC problem's difficulty. A 10-unit test system is used for the simulation, which is run for a whole day to demonstrate the effectiveness of the suggested approach. The proposed algorithm's output is compared with the best-known approaches from various references. The simulated results generated by the suggested algorithms and the previously reported algorithms to solve the PBUC problem show that the proposed method is better than other evolutionary methods utilized in this study and prior investigations. For example, the overall profit from the suggested MSFLA is around 4% and 5.5% higher than that from other algorithms like the ICA and Muller methods in the presence and absence of reserve allocation, respectively. Furthermore, the MSFLA emissions value is approximately 2% and 8% lower than the optimum emissions values obtained using the PSO and ICA approaches, respectively. [ABSTRACT FROM AUTHOR]

The subject of the article was the chemical analysis of gasoline and exhaust gas samples taken from an urban two-wheeled vehicle. The main aim of the work was to identify chemical compounds emitted by a group of urban two-wheeled vehicles depending on the engine's operating parameters. First, engine operating parameters and driving parameters of three urban two-wheeled vehicles were measured in real operating conditions. Based on the averaged results, engine operating points were determined for exhaust gas samples that were collected into Tedlar bags. The exhaust gas composition of individual chemical substances obtained in the chromatographic separation process were subjected to a detailed analysis relating the engine operating point with their emission rate, with each individual component being assessed in terms of its impact on human health. The obtained qualitative analysis results indicated the presence of alkenes, alkanes, aliphatic aldehydes, and aromatic and cyclic hydrocarbons (cycloalkanes) in the tested samples. The experiments provided a variety of conclusions relating to the operating parameters of a two-wheeler engine. Qualitative assessment of exhaust samples showed that a two-wheeled vehicle was characterized by the most varying composition of BTX aromatic hydrocarbons derivatives, which are particularly dangerous to human health and life. Therefore, the authors suggest that in the future, approval procedures regarding toxic emissions should be extended to include chromatographic tests. The presented results are an extension of previous studies on toxic emissions from urban two-wheeled vehicles in real operating conditions that were published in other journals. [ABSTRACT FROM AUTHOR]

As an escalating global concern for environmentally sustainable marine fuels, liquefied petroleum gas (LPG) is attracting attention as an eco-friendly and economical alternative. This study explored LPG utilization in small marine vessels, focusing on its eco-friendliness and economic feasibility. To assess its environmental implications, the AVL FIRE simulation program was used to compare CO2, CO, NO, and soot emissions from LPG engines with those from conventional gasoline and diesel engines. The LPG engine model relied on data from a pioneering type-approved experimental LPG engine designed for small South Korean marine vessels, while parameters for gasoline and diesel engines were adjusted to suit their distinctive features. Regarding long-term economic feasibility, assuming a 30-year ship lifespan, incorporating 2022 annual average prices, average annual price growth rates, and annual fuel consumption data of each fuel, results indicate that LPG engines exhibited lower CO2, CO, NO, and soot emissions than conventional engines, except that NO emissions were higher than gasoline engines. Evaluating LPG's economic feasibility over a 30-year ship life cycle for an individual vessel revealed varying fuel cost savings, with the greatest savings observed in gasoline–other (KRW 2220.7 million) and the least in gasoline–coastal (KRW 1152.5 million). These findings offer vital insights for ship operators and policymakers seeking a balance between eco-friendliness and cost-effectiveness, as well as LPG engine technology emerging as pivotal for a sustainable future, harmonizing environmental protection and economic viability. [ABSTRACT FROM AUTHOR]

The paper discusses the results of investigations of the change in thermal and emission-related parameters of a heating boiler fueled with biomass after a modification with a proprietary flue gas recirculation system made for this type of equipment. The results provide insight into the combustion process with a multistage flue gas recirculation that materially affected the boiler operation: a reduction in the mass concentration of nitrogen oxides (NOx) by reducing the combustion temperature. The authors also observed a reduction in the emission of particulate matters (PM) and carbon monoxide (CO). For the investigations, the authors used a heating boiler fitted with an automatic fuel feed (timber pellets) and a proprietary patented flue gas recirculation system (Polish patent Pat. 243395) for low power solid fuel heating boilers. Aside from the measurement of the mass concentration of the emitted pollutants, the research focused on the measurements of the temperature inside the combustion chamber, the temperature of the flue gas and the level of oxygen in the flue gas. The aim of the research was to confirm the validity of using the flue gas recirculation technique to reduce emissions of harmful substances from biomass heating boilers, as a technique not previously used for this group of devices. Moreover, the aim of the research was to test an original engineering solution, in the form of a flue gas distribution valve, and investigate its effect on reducing NOx emissions and improving other thermal and emission parameters of the boiler. The obtained research results confirm the validity of the chosen actions and provide a positive premise for the practical use of this technology in solid fuel heating boilers. [ABSTRACT FROM AUTHOR]

This study systematically investigates the formation of NOx in the thermal decomposition of N2O, focusing on the impact of Kelvin–Helmholtz (K-H) instability in combustion environments. Using premixed CH4 co-flow flames and an electric furnace as distinct heat sources, we explored NOx emission dynamics under varying conditions, including reaction temperature, residence time, and N2O dilution rates (XN2O). Our findings demonstrate that diluting N2O around a premixed flame increases flame length and decreases flame propagation velocity, inducing K-H instability. This instability was quantitatively characterized using Richardson and Strouhal numbers, highlighting N2O's role in augmenting oxygen supply within the flame and significantly altering flame dynamics. The study reveals that higher XN2O consistently led to increased NO formation independently of nozzle exit velocity (ujet) or co-flow rate, emphasizing the influence of N2O concentration on NO production. In scenarios without K-H instability, particularly at lower ujet, an exponential rise in NO2 formation rates was observed, due to the reduced residence time of N2O near the flame surface, limiting pyrolysis effectiveness. Conversely, at higher ujet where K-H instability occurs, the formation rate of NO2 drastically decreased. This suggests that K-H instability is crucial in optimizing N2O decomposition for minimal NOx production. [ABSTRACT FROM AUTHOR]

In this study, we reviewed smog chamber systems and methodologies used in secondary organic aerosol (SOA) formation studies. Many important chambers across the world have been reviewed, including 18 American, 24 European, and 8 Asian chambers. The characteristics of the chambers (location, reactor size, wall materials, and light sources), measurement systems (popular equipment and working principles), and methodologies (SOA yield calculation and wall-loss correction) are summarized. This review discussed key experimental parameters such as surface-to-volume ratio (S/V), temperature, relative humidity, light intensity, and wall effect that influence the results of the experiment, and how the methodologies have evolved for more accurate simulation of atmospheric processes. In addition, this review identifies the sources of uncertainties in finding SOA yields that are originated from experimental systems and methodologies used in previous studies. The intensity of the installed artificial lights (photolysis rate of NO2 varied from 0.1/min to 0.40/min), SOA density assumption (varied from 1 g/cm3 to 1.45 g/cm3), wall-loss management, and background contaminants were identified as important sources of uncertainty. The methodologies developed in previous studies to minimize those uncertainties are also discussed. [ABSTRACT FROM AUTHOR]

The exceptional properties of methanol, such as its high octane number and latent heat of evaporation, make it an advantageous fuel for efficient utilization in dual-fuel combustion techniques. The aim of this study is to investigate the effect of direct methanol injection timing on the combustion, performance and emission characteristics of a dual-fuel spark ignition engine at different injection pressures. We conducted four different direct injection pressure tests ranging from 360° ahead to 30° CA ahead at 30° CA intervals. The experimental results indicate that regardless of the injection pressure, altering the methanol injection timing from −360° to −30° CA ATDC leads to distinct combustion behavior and changes in the combustion phase. Initially, as the injection timing is delayed, the combustion process accelerates, which is followed by a slower combustion phase. Additionally, the combustion phase itself experiences a delay and then advances. Regarding performance characteristics, both the brake thermal efficiency (BTE) and exhaust gas temperature (EGT) exhibit a consistent pattern of first increasing and then decreasing as the injection timing is delayed. This suggests that there is an optimal injection timing window that can enhance both the engine's efficiency and its ability to manage exhaust temperature. In terms of emissions, there are different trends in this process due to the different conditions under which the individual emissions are produced, with CO and HC showing a decreasing and then increasing trend, and NOx showing the opposite trend. In conclusion, regardless of the injection pressure employed, adopting a thoughtful and well-designed injection strategy can significantly improve the combustion performance and emission characteristics of the engine. The findings of this study shed light on the potential of methanol dual-fuel combustion and provide valuable insights for optimizing engine operation in terms of efficiency and emissions control. [ABSTRACT FROM AUTHOR]

A novel Eu(tta)3([4,4′-(t-bu)2-2,2′-bpy)] complex (tta-thenoyltrifluoroacetone), a ratiometric luminescent-based optical sensor for the quantitative determination of aluminum ion, is synthesized and characterized using XRD and 1H NMR. The XRD data reveal the slightly distorted octahedral structure. The complex displays a bright red emission at 613 nm in methanol which is characteristic of europium (III) complexes. Upon the addition of Al3+ ions, the red emission disappears, and a new blue emission at 398 nm emerges, manifesting the ratiometric nature of the complex. The turn-off of the red emission and turn-on of the blue emission are attributed to Eu-Al trans-metalation, as supported by Raman data that show the emergence of Al-O vibrations at 418, 495, and 608 cm−1 concomitant with the disappearance of Eu-O and Eu-N bond vibrations. Most aluminum sensors are known to suffer from interferences from other metals including Cu2+, Co2+, and Cd2+. However, the sensor reported here is tested for 11 common cations and shows no interference on sensitivity. To the best of our knowledge, this is the first known Eu-based luminescence sensor that successfully exhibited the ability to detect aluminum ions in ppb levels in aqueous environments. The calculated Al3+ binding constant is 2.496 × 103 ± 172. The complex shows a linear relationship in the range of 0–47.6 ppb (1.76 × 10−6 M) Al3+ and the limit of detection (LOD) is 4.79 ppb (1.77 × 10−7 M) in MeOH. ICP-OES is used for validation of the sensor complex in water and then it was used for quantitative detection of Al3+ ions in water as a real-life application. The complex can accurately detect Al3+ ions in the range of 4.97–24.9 ppb (1.84 × 10−7 M–9.2 × 10−7 M) with an LOD of 8.11 ppb (2.99 × 10−7 M). Considering that the aluminum ion serves no recognized function within the human body, its accumulation can lead to severe neurological disorders, including Parkinson's and Alzheimer's diseases. With the LOD value significantly lower than the WHO-recommended maximum permissible level of 200 ppb for aluminum in drinking water, even without high-power laser-aided signal enhancement, the sensor shows promise for detecting trace amounts of aluminum contamination in water. Therefore, it can significantly aid in the monitoring of even the smallest aluminum ion contamination in drinking water, industrial effluents, and natural water bodies. [ABSTRACT FROM AUTHOR]

The hand-held power sander is a frequently used tool in woodworking, and it is a significant source of risk in terms of dust, vibration, and, notably, noise. The purpose of a hand-held power sander manufacturer's noise emission statement is to provide information that is useful for assessing the risks associated with noise exposure and should assist users in selecting a hand-held power sander with reduced noise emissions. The stated levels of emitted noise obtained in accordance with a harmonized test procedure may not, in all circumstances, give a reliable indication of the actual risk of noise exposure during the typical use of a hand-held power sander. The aim of this work was to investigate the difference between the values declared by the manufacturers of hand-held power sanders and the measured noise values during actual use. The measurements of the equivalent sound pressure levels were carried out using an integrating–averaging sound level meter (B&K, model 2245) during the sanding of beech and spruce wood with different types of hand-held electric sanders (belt, random orbital, and orbital) with abrasives of coarse, medium, or fine grit. Upon comparing the measured and declared noise values, differences ranging from −6.3 dB to 19 dB(A) were identified for distinct sander types. The results of this study show that the use of declared noise emission values during risk assessments underestimates the magnitude of operator noise exposure. [ABSTRACT FROM AUTHOR]

This study addresses the pressing environmental problem of the emissions of ecotoxic heavy metals from high-temperature waste combustion processes, including incineration and pyrolysis. Such emissions pose a serious threat to ecosystems and human health. This study investigated the behaviour of the heavy metals Cu, Ni, and Pb during the combustion of various waste materials such as plastic waste, pharmaceutical waste, and pesticide waste. To limit the release of heavy metals into the exhaust gas stream, various additives were used: divanadium pentoxide (V2O5), borax (Na2B4O7), and their mixtures with calcium oxide (CaO). Additionally, this study examined the impact of the content of chlorine heteroatoms (Cl) in burned waste materials on the emission levels of Cu, Ni, and Pb. The findings shed light on the mobility of ecotoxic heavy metals in high-temperature waste incineration processes (1273, 1373 K) and offer insight into strategies to improve their immobilisation in grate residues. At a temperature of 1273 K, V2O5 with CaO reduced Pb emissions by ~65% for plastic waste and by ~40% for pesticide. [ABSTRACT FROM AUTHOR]

Signalized intersections are one of the typical bottlenecks in urban transport systems that have reduced speeds and which have substantial vehicle emissions. This study aims to analyze and optimize the impacts of signal control on the emissions of mixed traffic flow (CO, HC, and NOx) containing both heavy- and light-duty vehicles at urban intersections, leveraging high-resolution field emission data. An OBEAS-3000 (Manufacturer: Xiamen Tongchuang Inspection Technology Co., Ltd., Xiamen, China.) vehicle emission testing device was used to collect microscopic operating characteristics and instantaneous emission data of different vehicle types (light- and heavy-duty vehicles) under different operating conditions. Based on the collected data, the VSP (Vehicle Specific Power) model combined with the VISSIM traffic simulation platform was used to quantitatively analyze the impact of signal control on traffic emissions. Heavy-duty vehicles contribute to most of the emissions regardless of the low proportion in the traffic flows. Afterward, a model is proposed for determining the optimal signal control at an intersection for a specific percentage of heavy-duty vehicles based on the conversion of emission factors of different types of vehicles. Signal control is also optimized based on conventional signal timing, and vehicle emissions are calculated. In the empirical analysis, the changes in CO, HC, and NOx emissions of light- and heavy-duty vehicles before and after conventional signal control optimization are quantified and compared. After the signal control optimization, the CO, HC, and NOx emissions of heavy-duty vehicles were reduced. The CO and HC emissions of light-duty vehicles were reduced, but the NOx emissions of light-duty vehicles remained unchanged. The emissions of vehicles after optimized signal control based on vehicle conversion factors are reduced more significantly than those after conventional optimized signal control. This study provides a scientific basis for developing traffic management measures for energy saving and emission reduction in transport systems with mixed traffic. [ABSTRACT FROM AUTHOR]

Owing to society's growing ecological awareness, researchers and car manufacturers have increasingly been focusing on the adverse impact of transport on the environment. Many scientific publications have been published addressing the influence of a variety of factors on the exhaust emissions generated by vehicles and machinery. In this paper, the authors present an analysis of the exhaust emissions of components such as CO, THC, and NOx in relation to the type and condition of the road surface. The analysis was performed on a heavy-duty truck designed for carriage of timber. The investigations were carried out with the use of the PEMS equipment (portable emission measurement system) on bitumen-paved roads and unpaved forest access roads. The portable measurement system allowed for an accurate determination of the influence of the road conditions on the operating parameters of the vehicle powertrain and its exhaust emissions. Additionally, the authors present the influence of the type of road surface on the vehicle fuel consumption calculated based on the carbon balance method. [ABSTRACT FROM AUTHOR]

Knowing and understanding the parameters influencing the concentration of particles created by brake wear, as one of the main contributors to non-exhaust emissions from vehicles, is important for the further development of systems on vehicles to reduce the concentration of particles, and also for further research in the field of developing new friction pairs. In this research, a brake inertial dynamometer was used to measure brake particles, and four different brake pads were examined. Based on a previous review of the applied tests and driving cycles, the braking parameters were determined, i.e., the initial simulated speed of the vehicle, the load of one-quarter of the vehicle, and the brake pressure. The ambient temperature, air humidity, coefficient of friction between friction pairs, deceleration, and braking time can have an influence depending on the brake pad. Further, during the measurement, the temperatures of the brake pads were also measured, where the initial temperature of the brake pads was always the same. In order to process the data, several methods were used, including the presentation of the obtained results in a time domain, the application of the Taguchi design of the experiment with the analysis of the parameters, and a correlation analysis using the Pearson and Spearman correlation coefficients. In this research, the authors concluded that the influences of the parameters primarily depend on the applied brake pads. The vehicle speed turned out to have a large influence in all cases, as did the load, i.e., the influence of the vehicle weight (indirectly through the kinetic energy of the vehicle). In this case, the pressure showed less influence on the particle concentration. An important braking parameter that has a significant impact on the concentrations of PM2.5 and PM10 particles is the final temperature of the brake pads. [ABSTRACT FROM AUTHOR]

The transportation demands of people are increasing day by day depending on the population, and the number of vehicles in traffic is causing various problems. To meet the energy needs of vehicles, there is a huge burden on countries in terms of fossil fuels. In addition, the use of fossil fuels in vehicles has a serious impact on environmental pollution. Various studies have been carried out to prevent unnecessary fuel consumption and emissions. Behavior of drivers, who are important components of traffic, are carefully examined in the context of this subject. Driver distraction causes various environmental problems as well as traffic safety issues. In this study, the negative situations that arise as a result of drivers waiting at traffic lights dealing with their mobile phones are discussed. Roadside observations are made for drivers at considered intersections in Erzurum Province, Turkey. As a result of these observations, delays at selected intersections due to mobile phone use are calculated. Unnecessary fuel consumption and emissions due to delays are also analyzed. An annual fuel consumption of approximately 177.025 L and emissions of 0.294 (kg) NOX and 251.68 (kg) CO2 occur at only selected intersections. In addition, a second roadside observation is made in order to analyze driver behavior and the most preferred type of mobile phone usage is determined. It is seen that drivers mostly exhibit the "Talking" and "Touchscreen" action classes. Considering the economic conditions and environmental pollution sensitivities of countries, attempts have been made to raise awareness about fuel consumption and emissions at traffic lights. [ABSTRACT FROM AUTHOR]

Industrialization, anthropogenic activities, the exhaust of vehicles and exponential population growth have a significant impact on the outdoor air quality of megacities across the world. Karachi is one of the largest cities in Pakistan, South Asia. The dense population, rapid economic growth and unplanned industrial activities have improved the socioeconomic status but also deteriorated the air quality of Karachi. The severe increase in air pollution has become a threat to the local population in terms of their health issues, quality of life and environment. Therefore, it is essential to quantify and monitor the spatiotemporal variation in outdoor air quality parameters. The current study aims to monitor the air quality in four major industrial zones of Karachi for three years (2020–2022). The field data was collected during the periods of post-monsoon and pre-monsoon using the HAZ-SCANNER (HIM-6000) apparatus, which measured outdoor air pollutants such as carbon monoxide (CO), nitrogen oxides (NO2), sulfur dioxide (SO2) and particulate matter (PM10, PM2.5 and TSPM). The data from 24 stations was analyzed using statistical analysis tools to estimate the parameters and Arc GIS to map the spatial variation of each parameter. The result shows that the concentration of particulate matter (TSPM, PM2.5 and PM10), SO2, NO2 and CO values at sampling sites are moderate in the post-monsoon season as compared to the pre-monsoon season due to cyclical monsoon effects and exceed the environmental quality standards. It was also noted that the North Karachi industrial area is at lower risk due to the small-scale industry. The higher levels of air pollutants have numerous health implications and may cause chronic infections. The air pollutant has a severe impact on plant growth and soil. Therefore, it is important to implement local environmental standards regarding outdoor air pollutants to mitigate the adverse impact on human health and economic activities. [ABSTRACT FROM AUTHOR]

The carbon (C) cycle in inland waters, including carbon concentrations in and carbon dioxide (CO2) emissions from water surfaces, are at the forefront of biogeochemical studies, especially in regions strongly impacted by ongoing climate change. Towards a better understanding of C storage, transport and emission in Central Asian mountain regions, an area of knowledge that has been extremely poorly studied until now, here, we carried out systematic measurements of dissolved C and CO2 emissions in rivers and lakes located along a macrotransect of various natural landscapes in the Sayan–Altai mountain region, from the high mountains of the Western Sayan in the northwest of Tyva to the arid (dry) steppes and semideserts in the intermountain basins in the southeast of Tyva on the border with Mongolia. New data on major hydrochemical parameters and CO2 fluxes (fCO2) gathered by floating chambers and dissolved organic and inorganic carbon (DOC and DIC, respectively) concentrations collected over the four main hydrological seasons allowed us to assess the current C biogeochemical status of these water bodies in order to judge possible future changes under climate warming. We further tested the impact of permafrost, river watershed size, lake area and climate parameters as well as 'internal' biogeochemical drivers (pH, mineralization, organic matter quality and bacterial population) on CO2 concentration and emissions in lakes and rivers of this region and compared them with available data from other subarctic and mountain settings. We found strong environmental control of the CO2 pattern in the studied water bodies, with thermokarst lakes being drastically different from other lakes. In freshwater lakes, pCO2 negatively correlated with O2, whereas the water temperature exerted a positive impact on pCO2 in large rivers. Overall, the large complexity of counteracting external and internal drivers of CO2 exchange between the water surfaces and the atmosphere (CO2-rich underground DIC influx and lateral soil and subsurface water; CO2 production in the water column due to dissolved and particulate OC biodegradation; CO2 uptake by aquatic biota) precluded establishing simple causalities between a single environmental parameter and the fCO2 of rivers and lakes. The season-averaged CO2 emission flux from the rivers of Tyva measured in this study was comparable, with some uncertainty, to the C uptake fluxes from terrestrial ecosystems of the region, which were assessed in other works. [ABSTRACT FROM AUTHOR]

The two-stroke engine has many advantages, including low maintenance costs, a high specific power, and a simple structure, compared to four-stroke engines. Since two-stroke engines use a fuel–oil mixture instead of fuel alone, two-stroke engines do not need an oil pan. Unlike the lubrication system in four-stroke engines, the moving parts are lubricated with a fuel–lubricant mixture. As long as the engine is running, the fuel and lubricant burn together. The combustion of this fuel–lubricant mixture can adversely affect exhaust emissions and cause excessive carbon deposits on the spark plug. In this paper, experiments were carried out using different amounts of oil (100:3, 100:3.5, and 100:4 vol.) in a two-stroke gasoline-powered generator. In addition, we attempted to improve the lubricant's properties by adding hBN (0.5% vol. or 1.3% wt.) to the lubricant. It was observed that the flash point and pour point did not change as a result of the addition of hBN to the lubricant, and the density and viscosity index increased linearly depending on the amount of hBN. In a series of experiments, the generator was examined for performance and emissions. With the addition of hBN, there was a significant decrease in the specific fuel consumption and exhaust gas temperature, the CO2 increased, and the CO and HC decreased. These results show that hBN improves combustion. As a result, it was reported that reducing the amount of lubricant leads to increased emissions and decreased performance. It was found that when 0.5% hBN by volume is added to the lubricant, the lubricating property improves, and thus, the amount of oil added to the fuel can be reduced to an acceptable level (from 100:4 to 100:3.5) without causing mechanical failure in the engine. [ABSTRACT FROM AUTHOR]