Search

Physical vapor deposition (PVD) provides a route to prepare highly stable and anisotropic organic glasses that are utilized in multi-layer structures such as organic light-emitting devices. While previous work has demonstrated that anisotropic glasses with uniaxial symmetry can be prepared by PVD, here, we prepare biaxially aligned glasses in which molecular orientation has a preferred in-plane direction. With the collective effect of the surface equilibration mechanism and template growth on an aligned substrate, macroscopic biaxial alignment is achieved in depositions as much as 180 K below the clearing point TLC−iso (and 50 K below the glass transition temperature Tg) with single-component disk-like (phenanthroperylene ester) and rod-like (itraconazole) mesogens. The preparation of biaxially aligned organic semiconductors adds a new dimension of structural control for vapor-deposited glasses and may enable polarized emission and in-plane control of charge mobility. [ABSTRACT FROM AUTHOR]

EU is actively moving towards the implementation of Euro-7 regulations, thus placing a strong emphasis on real-road emissions. Euro-7 introduced OBM (on-board monitoring), which is an enhancement of regulations that closely replicates real-world road conditions. Furthermore, there is a need to devise an effective application strategy for utilizing the driving monitoring data prior to the enforcement of OBM. This study addresses these challenges by conducting RDE (real-driving emission) tests on both 3.5-ton and 25-ton commercial vehicles to gather CO2 emissions and engine control unit data accessible through an OBD (on-board diagnostics) port. To process the RDE data, an appropriate machine learning model, XGBoost, was selected and trained. The outcome of our CO2 emission prediction for the two vehicles demonstrated that employing monitoring data yielded reliable estimates of actual road CO2 emissions. Finally, a comparative analysis was conducted between the proposed monitoring approach and the fuel-based CO2 monitoring method using the emission factor from EMEP/EEA air pollutant emission inventory guidebook 2019 utilizing fuel consumption data achieved through the OBFCM (on-board fuel and energy consumption monitoring) rule. Our method, which is based on predictive CO2 emissions monitoring, exhibited significantly greater accuracy. This outcome underscores the necessity to adopt the proposed approach. [ABSTRACT FROM AUTHOR]

Effective emission control technologies and eco-friendly propulsion systems have been developed to decrease exhaust particle emissions. However, more work must be conducted on non-exhaust traffic-related sources such as tyre wear. The advent of automated vehicles (AVs) enables researchers and automotive manufacturers to consider ways to further decrease tyre wear, as vehicles will be controlled by the system rather than by the driver. In this direction, this work presents the formulation of an optimal control problem for the trajectory optimisation of automated articulated vehicles for tyre wear minimisation. The optimum velocity profile is sought for a predefined road path from a specific starting point to a final one to minimise tyre wear in fixed time cases. Specific boundaries and constraints are applied to the problem to ensure the vehicle's stability and the feasibility of the solution. According to the results, a small increase in the journey time leads to a significant decrease in the mass loss due to tyre wear. The employment of articulated vehicles with low powertrain capabilities leads to greater tyre wear, while excessive increases in powertrain capabilities are not required. The conclusions pave the way for AV researchers and manufacturers to consider tyre wear in their control modules and come closer to the zero-emission goal. [ABSTRACT FROM AUTHOR]

Organic luminescent materials with time‐dependent emission colors show promising applications in the fields of chemical sensing, high‐resolution bioimaging, and high‐security information encryption. Herein a time‐dependent fluorescence system based on a spirocyclic scaffold‐bridged cyanostilbene dimer (SDCS) as the single component in a mixed CH3CN/H2O solvent is presented. Specifically, the original orange‐emitting nanoparticles prepared from SDCS by reprecipitation can transform into green‐emitting nanosheets over time driven by supramolecular self‐assembly. It is worth noting that such a transformation rate can be controlled by tuning the water fraction. Based on these unique properties, fluorescent binary codes are developed, enabling time‐dependent information encryption with a higher level of security. Moreover, the dual color can be individually fixed by solid matrices such as hydrogel or powder. The obtained luminescent powders are successfully used in two‐color fluorescence imaging of latent fingerprints. This work demonstrates the use of a supramolecular strategy to control multiple emissions in a single‐component system for multifunctional applications. [ABSTRACT FROM AUTHOR]

Elevated atmospheric reactive nitrogen (Nr) emissions and the subsequent nitrogen (N) deposition have negatively impacted the global environment, particularly in China. In order to assess the long-term trends in atmospheric N deposition in the south of China, Taojiang County in Hunan Province was selected as a representative rural area for study. We analyzed interannual variation in atmospheric Nr, including gaseous ammonia (NH3), nitrogen dioxide (NO2), nitrate acid (HNO3) vapor, particulate ammonium (NH4+), and nitrate (NO3−) in air and NH4+-N and NO3−-N in precipitation from 2011 to 2020. The 10-year average atmospheric wet-plus-dry N deposition was 41.9 kg N ha−1 yr−1, which decreased by approximately 24% after 2012, indicating that NH3 and NOx emissions were effectively reduced by emission controls introduced in 2013. Wet deposition accounted for approximately 74% of the total N deposition and was significantly influenced by annual precipitation amount. Reduced N (NH3, pNH4+, and NH4+ in rainwater) was the dominant form, comprising approximately 58% of the total N deposition, while oxidized N (pNO3−, NO2, HNO3, and NO3− in rainwater) accounted for 42% of the total N deposition. Atmospheric HNO3, NO2, and NH3 concentrations and deposition declined by 30–80% over the decade, while particulate NH4+ and NO3− concentrations and deposition remained at relatively stable levels, which suggests that ongoing research and policy should focus on rural particulate pollution. Future strategies must concentrate on the integrated control of NH3 and NOx emissions to mitigate air pollution and protect human health, particularly in rural areas because current abatement efforts are primarily directed toward urban areas and the industrial sector, whereas non-point source NH3 pollution, influenced mainly by agricultural activities, dominates in rural regions. [ABSTRACT FROM AUTHOR]

An oxidizing and harmful pollutant gas, tropospheric ozone is a product of a complex set of photochemical reactions that can make it difficult to enact effective control measures. A better understanding of its precursors including volatile organic compounds (VOCs) and nitrogen oxides (NOx) and their spatial distribution can enable policymakers to focus their control efforts. In this study we used low-cost sensors (LCSs) to increase the spatial resolution of an existing NO2 monitoring network in addition to VOC sampling to better understand summer ozone formation in Maricopa County, Arizona, and observed that afternoon O3 values at the downwind sites were significantly correlated, ~0.27, to the morning NO2 × rate values at the urban sites. Additionally, we looked at the impact of wildfire smoke on ozone exceedances and compared non-smoke days to smoke days. The average O3 on smoke days was approximately 20% higher than on non-smoke days, however, the average NO2 concentration multiplied by estimated photolysis rate (NO2 × rate) values were only 2% higher on smoke days. Finally, we evaluated the ozone sensitivity of the region by calculating HCHO/NO2 ratios using three different datasets: ground, satellite, and model. Although the satellite dataset produced higher HCHO/NO2 ratios than the other datasets, when the proper regime thresholds are applied the three datasets consistently show transition and VOC-limited O3 production regimes over the Phoenix metro area. This suggests a need to implement more VOC emission controls in order to reach O3 attainment in the county. [ABSTRACT FROM AUTHOR]

Air quality in urban areas is mainly controlled by emission sources and dispersion conditions. The mixing layer height (MLH) within which the pollutants are dispersed plays an important role in air pollution assessment. In this study, the MLH was determined based on the daily radon flux obtained from the European radon flux map and outdoor radon concentration measured in Bratislava, Slovakia. The radon-based MLH was compared with the boundary layer height obtained from the ERA-5 reanalysis dataset, showing good agreement. Using the Sturges grouping method and regression analysis, radon-based MLH showed significant correlations with the concentration of various atmospheric pollutants. [ABSTRACT FROM AUTHOR]

Subsurface exploration of ice-covered planets and moons presents communications challenges because of the need to communicate through kilometers of ice. The objective of this task is to develop the capability to wirelessly communicate through kilometers of ice and thus complement the potentially failure-prone tethers deployed behind an ice-penetrating probe on Ocean Worlds. In this paper, the preliminary work on the development of wireless deep-ice communication is presented and discussed. The communication test and acoustic attenuation measurements in ice have been made by embedding acoustic transceivers in glacial ice at the Matanuska Glacier, Anchorage, Alaska. Field test results show that acoustic communication is viable through ice, demonstrating the transmission of data and image files in the 13–18 kHz band over 100 m. The results suggest that communication over many kilometers of ice thickness could be feasible by employing reduced transmitting frequencies around 1 kHz, though future work is needed to better constrain the likely acoustic attenuation properties through a refrozen borehole. [ABSTRACT FROM AUTHOR]

With the in-depth promotion of low-carbon economic transformation and air pollution control, the role of synergetic control of CO2 and air pollutant emissions has begun to stand out. Based on panel data for 30 provinces in China from 2012 to 2020, we measured the coupling and coordination degree of CO2 and air pollutant emissions control (CCD) and revealed the direct effect of human capital on CCD, the heterogeneous effect, and the threshold effect of R&D intensity. The results of the study showed that, firstly, CCD at the provincial level in China showed a stepped-up trend and regional heterogeneity. Second, human capital had a significant positive effect on CCD, and this effect was stronger in the "Four Provinces of Shan-He" and Inland provinces. Third, R&D intensity played a significant threshold role in the impact of human capital on CCD, but there was a "medium-term trap". Therefore, based on the development of differentiated synergistic strategies for pollution and carbon reduction, financial investment in human capital and R&D activities should be increased. [ABSTRACT FROM AUTHOR]

We use new survey data from 1,203 households in rural Eastern India to estimate cross-sectional models of overall energy use and embedded emissions. Findings indicate that the primary driver of household energy use is household size and affluence. This is unsurprising and consistent with findings from the engineering literature on energy demand. However, there is also a substantial and significant moderating influence of skills on energy use. For emissions, we observe a bifurcated relationship in line with educational attainment. For those that have completed secondary education or more, skills are negatively associated with energy use and emissions, whereas for those with lesser qualifications more skills are associated with more energy use and emissions. The results are consistent with the environmental Kuznets curve, which implies that a critical level of affluence is required before environmental impacts start lessening. The results also echo a sociological critique of human capital theory − that individual abilities are not productive in and of themselves, but rather in relation to socially determined opportunity structures. Our findings show that this could also hold for greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

Despite recent advances, it is still difficult to fabricate deep blue‐emitting perovskite light‐emitting diodes (LEDs) that are immune to the color instability caused by halide mixing. This is largely because it is still challenging to achieve bright, stable, pure bromide perovskite materials with deep blue emission. Here, a novel strategy is reported for synthesizing ultrasmall CsPbBr3 quantum dots (QDs) under ambient conditions. Precise size control is used to tune the peak emission wavelengths, via the confinement effect, from 433 to 501 nm. These ultrasmall QDs, with sizes of 2–6 nm, exhibit ultralow trap density and stable photoluminescence quantum yields up to 94%, particularly in the deep blue spectral region (440–465 nm). QD‐LEDs fabricated with these materials achieve an external quantum efficiency of 1.0% at 459 nm. The exceptional control of the emission properties demonstrated here suggests a new strategy for building stable, efficient blue QD‐LEDs. [ABSTRACT FROM AUTHOR]

The decarbonisation of the maritime sector is one of the world's priorities to reduce the volume of polluting emissions. The basis of this decarbonisation is the adaptation of existing ships to emission control regulations by means of transformations, installation of new equipment, development of new low-emission fuels and development of the infrastructure that makes the supply of this new generation of fuels feasible. In addition, hydrogen is the energy vector for all these new technologies, and its role over the next 30 years needs to be addressed. In a changing global situation such as the one we are currently experiencing; this article has the objective of making a review paper on the different fuels currently being used in the maritime sector and the existing alternatives. It also discusses the situation and the impact the current environmental situation has on the world ship order book, both in terms of legislation and economics. As a conclusion, the Liquefied Natural Gas (LNG) will have a very important role to play as a bridge between the current situation and the development of hydrogen technology. Hydrogen is an energy vector that can achieve the decarbonisation objectives by 2050. Storage problems, lack of infrastructures to supply it and the development of technology and regulations are the major challenges it will have to face. Biofuels also present a serious proposal for the decarbonisation of the sector, and the role of hydrogen in their composition, is essential to achieve green fuel generation. [ABSTRACT FROM AUTHOR]

One of the principal sources of pollution, on a local scale for a water city, with a tourist and commercial port, is certainly the port. Monitoring what is happening here is essential in order to implement suitable measures to control and contain emissions with consideration for the increasingly delicate environmental problem. This paper details the methods and results of an experimental campaign of local-scale emission measurements conducted in the port of Naples for two weeks in 2021. The chosen instrumentation, its setup, post-processing of the data, and an analysis critique of the results will be presented in detail. The campaign is part of broader research attempting to superimpose the concentrations of pollutants measured ashore in the port area with what is emitted by moored ships. [ABSTRACT FROM AUTHOR]

The premise for formulating effective emission control strategies is to accurately and reasonably evaluate the actual emission level of vehicles. Firstly, the active subspace method is applied to set up a low-dimensional model of the relationship between CO2 emission and multivariate vehicle driving data, in which the vehicle specific power (VSP) is identified as the most significant factor on the CO2 emission factor, followed by speed. Additionally, acceleration and exhaust temperature had the least impact. It is inferred that the changes in data sampling transform the establishment of subspace matrices, affecting the calculation of eigenvector components and the fitting of the final quadratic response surface, so that the emission sensitivity and final fitting accuracy are impressionable by the data distribution form. For the VSP, the best fitting result can be obtained when the VSP conforms to a uniform distribution. Moreover, the Bayesian linear regression method accounts for fitting parameters between the VSP and CO2 emission factor with uncertainties derived from heteroscedastic measurement errors, and the values and distributions of the intercept and slope α and β are obtained. In general, the high-resolution inventory of the carbon emission factor of the tested vehicle is set up via systematically analyzing it, which brings a bright view of data processing in further counting the carbon footprint. [ABSTRACT FROM AUTHOR]

Urgent emission reduction and community adaptation efforts are necessary to avert catastrophic climate-change harms. To assess our nation's progress toward such eforts, this Article develops a comprehensive structural analysis of U.S. climate policy at the federal, state, and local levels. It observes that current climate policies reflect disparate ®deral, state, and local strategies around emissions regulation, emission reduction subsidies, adaptation, and liability approaches. The Article then analyzes the dynamics between federal, state, and local strategies in these policy areas. This examination leads to some surprising conclusions. Under current policy alignments, further emission regulation measures do not appear to be realistic policy options. Though such regulatory measures have long been considered the most ellicient climate interventions, this analysis suggests they have little near-term prospect for further deployment. Rather, current dynamics among the states and federal government indicate that previously second- and third-choice policies, like subsidies and liability measures, have greater potential for expansion. Thus, these less-favored policy approaches may represent the best hopes for pressing emission reduction efforts. Further, the analysis suggests that while most climate adaptation policy is implemented at the local level, federal adaptation policies require the more immediate attention. Because federal adaptation policies reflect a deferential funding strategy, where the-federal government attempts to match support with state and local policy prejkrences, altering federal programs to better recognize state and local choices will enhance adaptation efforts at all levels of government. [ABSTRACT FROM AUTHOR]

The objective of this paper is to investigate the nonlinear relationship between ICT and CO2 emissions by controlling for economic growth, foreign direct investment, energy consumption, and trade openness. Using data from 16 Middle East and North African (MENA) countries over the period 1990–2019, we apply the Panel Smooth Transition Regression (PSTR) model, as introduced by (González A, Teräsvirta T, vanDijk D (2005) Panel smooth transition regression models. SEE/EFI Working Paper Series in Economics and Finance, No. 604), to study the potential regime-switching behavior of the relationship between the variables. The results reveal the existence of a strong regime-switching effect between ICT and CO2 emissions. It was found that after reaching a certain threshold, ICT use and penetration starts to significantly mitigate environmental degradation. Our results show that high levels of ICT not only improve environmental quality but can also be part of the solution to combat the environmental challenges that the MENA region has faced over the past decades. In addition, to account for the potential endogeneity bias, we also develop and estimate a PSTR model with instrumental variables (IV-PSTR) using the approach of (Fouquau et al., Econ Model 25:284–299, 2008). The results obtained confirm those initially found by the PSTR model. The study concludes with policy implications. [ABSTRACT FROM AUTHOR]

The effectiveness of carbon price in emissions trading schemes (ETS) is an important issue in China in the context of its ambitious climate change goals. This paper adopts a staggered difference-in-differences model to estimate whether China's ETS reduced CO2 emissions while maintaining economic growth even under low carbon prices. The results indicate that despite the low carbon prices, the ETS effectively reduced CO2 emissions without undermining the economy. Specifically, an increase of $1 in the carbon price reduced CO2 emissions by 1.69% and increased the per capita GDP by $286. The carbon price primarily achieved emission reduction and promoted economic development through channels, such as technological innovation, foreign direct investment, energy mix, and industrial structure. Carbon leakage to neighboring regions was not evident. Heterogeneity analysis showed that the environmental effects of the carbon price were more pronounced in regions with higher levels of economic development and CO2 emissions. Conversely, the economic effects of the carbon price were more pronounced in regions with lower levels of economic development and CO2 emissions. The carbon price achieved significant economic effects in regions that solely adopted the free allocation mode of emission allowances, while regions that used a combination of free allocation and auctioning experienced substantial emission reduction effects. Despite low carbon prices, China's ETS effectively reduced CO2 emissions without compromising economic growth. This finding provides new empirical evidence for the effectiveness of carbon price as well as decision support for the future promotion of ETS. Technological innovation, FDI, energy mix, and industrial structure are crucial channels through which the carbon price achieves emission reduction and promotes economic development. The absence of carbon leakage to neighboring regions suggests that ETS is an internally effective mechanism for emission control. Heterogeneity analysis showed that regional characteristics and allowance allocation modes can influence the effectiveness of carbon price, thus emphasizing the importance of targeted policy design and appropriate allocation methods. [ABSTRACT FROM AUTHOR]

The coordinated control of PM 2.5 and ozone has become the strategic goal of national air pollution control. Considering the gradual decline in PM 2.5 concentration and the aggravation of ozone pollution, a better understanding of the coordinated control of PM 2.5 and ozone is urgently needed. Here, we collected and sorted air pollutant data for 337 cities from 2015 to 2020 to explore the characteristics of PM 2.5 and ozone pollution based on China's five major air pollution regions. The results show that it is necessary to continue to strengthen the emission reduction in PM 2.5 and ozone precursors, and control NO x and VOCs while promoting a dramatic emission reduction in PM 2.5. The primary method of curbing ozone pollution is to strengthen the emission control of VOCs, with a long-term strategy of achieving substantial emission reductions in NO x , because VOCs and NO x are also precursors to PM 2.5 ; hence, their reductions also contribute to the reduction in PM 2.5. Therefore, the implementation of a multipollutant emission reduction control strategy aimed at the prevention and control of PM 2.5 and ozone pollution is the only means to realize the coordinated control of PM 2.5 and ozone. [ABSTRACT FROM AUTHOR]

Thermal emission is typically associated with a blackbody at a temperature above absolute zero, which exchanges energy with its environment in the form of radiation. Blackbody thermal emission is largely incoherent both spatially and temporally. Using principles in nanophotonics, thermal emission with characteristics that differ considerably from those of a blackbody has been demonstrated. In particular, by leveraging intrinsic properties of emerging materials or via nanostructuring at the wavelength or sub-wavelength scale, one can gain control over the directionality, temporal coherence, and other more exotic properties of thermal radiation. Typically, however, these are fixed at the time of fabrication. Gaining dynamic control of thermal emission requires exploiting external mechanisms that actively modulate radiative properties. Numerous applications can benefit from such thermal emission control, for example, in solar energy harvesting, thermo-photovoltaic energy conversion, radiative cooling, sensing, spectroscopy, imaging, and thermal camouflage. In this Tutorial, we introduce thermal emission in two domains: the far-field and the near-field, and we outline experimental approaches for probing thermal radiation in both ranges. We discuss ways for tailoring the spatial and temporal coherence of thermal emission and present available mechanisms to actively tune these characteristics. [ABSTRACT FROM AUTHOR]

The control of laser emission angles in laser devices is essential for many optoelectronic and photonic applications such as optical sensing and displays. In this context, we studied the light diffraction pattern of laser beams in a one-dimensional sampled distributed feedback resonator having organic gain media. The gratings consist of the repetition of supercells having a mixed-order sampled grating in which 1st-order gratings surround a 2nd-order grating. The experimental results showed that the diffraction angles of the laser beams are quite diverse depending on the supercell structures. We demonstrate that the interval of the diffraction angle (θ) of the laser beams is inversely proportional to the length of the supercell experimentally and theoretically. By tuning the length of supercells as well as the length of 1st-order and 2nd-order regions, the interval θ was tuned from 0.1° to 43° with the different arc emission patterns. With the reduction of θ, i.e., the longer 1st-order region, a significant decrease in the laser threshold was obtained, resulting in the lowest lasing threshold of 2.5 ± 0.1 μJ/cm2 with ∼3.5 ns of a long pulse width excitation source. [ABSTRACT FROM AUTHOR]

Knowledge of aerosol radiative effects in the Tibetan Plateau (TP) is limited due to the lack of reliable aerosol optical properties, especially the single scattering albedo (SSA). We firstly reported in situ measurement of SSA in Lhasa using a cavity enhanced albedometer (CEA) at λ = 532 nm from 22nd May to 11th June 2021. Unexpected strong aerosol absorbing ability was observed with an average SSA of 0.69. Based on spectral absorptions measured by Aethalometer (AE33), black carbon (BC) was found to be the dominated absorbing species, accounting for about 83% at λ = 370 nm, followed by primary and secondary brown carbon (BrCpri and BrCsec). The average direct aerosol radiative forcing at the top of atmosphere (DARFTOA) was 2.83 W/m2, indicating aerosol warming effect on the Earth‐atmosphere system. Even though aerosol loading is low, aerosol heating effect plays a significant role on TP warming due to strong absorbing ability. Plain Language Summary: The Tibetan Plateau (TP) has experienced rapid warming over the past decades, but the key factors affecting TP climate change haven't yet been clearly understood. Aerosol single scattering albedo (SSA) is a key optical parameter determining aerosol warming or cooling effect; however, reliable SSA measurement is scarce in TP. This study firstly reported in situ measurement of SSA in Lhasa and explored the direct radiative effect of aerosol on TP warming. Strong aerosol absorption, mainly contributed by black carbon (BC), was observed with an average SSA value of 0.69 in this city. Besides Lhasa, other sites over TP were also reported with low SSA (≤0.77) from surface measurement. The strong aerosol absorption could cause heating effect on the Earth‐atmosphere system. To relieve TP warming, reasonable pollutant emission control strategies should be taken urgently to weaken aerosol absorbing ability. Key Points: Unexpected low aerosol single scattering albedo was observed in Lhasa via in situ measurement of multiple optical parameters simultaneouslyBlack carbon was the dominant contributor (∼83%) to aerosol absorption at 370 nm, followed by primary and secondary brown carbonThe strong absorption in Lhasa exerted positive direct aerosol radiative forcing (warming effect) at the top of atmosphere [ABSTRACT FROM AUTHOR]

Current agricultural practices are increasingly favoring the biochar application to sequester carbon, enhance crop growth, and mitigate various environmental pollutants resulting from nitrogen (N) loss. However, since biochar's characteristics can vary depending on pyrolysis conditions, it is essential to determine the optimal standard, as they can have different effects on soil health. In this study, we categorized rice husk biochars basis on their pH levels and investigated the role of each rice husk biochar in reducing ammonia (NH3) emissions and promoting the growth of Chinese cabbage in urea-fertilized fields. The findings of this study revealed that the variation in pyrolysis conditions of rice husk biochars and N rates affected both the NH3 emissions and crop growth. The neutral (pH 7.10) biochar exhibited effective NH3 volatilization reduction, attributed to its high surface area (6.49 m2 g−1), outperforming the acidic (pH 6.10) and basic (pH 11.01) biochars, particularly under high N rates (640 kg N ha−1). Chinese cabbage yield was highest, reaching 4.00 kg plant−1, with the basic biochar application with high N rates. Therefore, the neutral rice husk biochar effectively mitigate the NH3 emissions from urea-treated fields, while the agronomic performance of Chinese cabbage enhanced in all biochar amendments. [ABSTRACT FROM AUTHOR]

Summary: Nowadays, multiple input multiple outputs with orthogonal frequency division multiplexing (MIMO‐OFDM) provide better communication performance that can be applied to the fast‐growing Internet of Things (IoTs). In underwater IoT, information fades away rapidly due to varying water conditions. Therefore, the MIMO model can be applied to the OFDM acoustic system, enabling high‐speed data transmission without affecting the channel effectively. However, detecting the underwater signal and estimating the channel is highly necessary for enhancing underwater acoustic communication (UWAC). Recently, many techniques have been introduced for effectively performing signal detection and channel estimation. However, those techniques face high time complexity due to increased channel interferences and noises during data transmission. Hence, this article brings a novel technique for SD and CE for the UWAC‐IoT‐enabled MIMO‐OFDM system. An adaptive recursive least square (ARLS) technique is proposed in this study for CE that aids in evaluating the acoustic channel parameters effectively. For performing SD, a bi‐directional deep pelican convolutional neural network (BDPCNN) technique is introduced to ensure the presence and absence of signals at the receiver end. The proposed method is analyzed via the MATLAB platform, and the performances are analyzed under different water types like turbid water, coastal water, clear ocean water, and pure seawater. Different performance metrics like bit error rate (BER), mean square error (MSE), energy efficiency (EE), and time complexity are analyzed with different existing techniques. The experimental section obtains the BER of 0.0086, 0.013, 0.017, and 0.021 for turbid, coastal, clear, and pure seawater, respectively. [ABSTRACT FROM AUTHOR]

Emerging research indicates that ground-level ozone (O3) has become a leading contributor to air quality concerns in many Chinese cities, with the Yangtze River Delta (YRD) region facing particular challenges. This study investigated the characterization of air pollutants in Wujiang, which is located within the YRD demonstration zone, during the warm season (April–September) of 2022. The contributions of emission and meteorology to O3 were identified, the O3-NOX-VOC sensitivities were discussed, and the VOC sources and their contributions to O3 formation were analyzed. A random forest model revealed that the high O3 concentration was mainly caused by a combination of increased emission intensity due to the resumption of work and production after the COVID-19 pandemic, along with adverse meteorological conditions. The results revealed more than 92% of the pollution days were related to O3 during the warm season, and the impact of O3 precursor emissions was slightly greater than that of the meteorological conditions. O3 formation was in the VOC-limited regime, and emission reduction strategies targeting VOCs, particularly aromatics such as toluene and xylene, have been identified as the most effective approach for mitigating O3 pollution. Changes in O3-NOX-VOC sensitivity were also observed from the VOC-limited regime to the transitional regime, which was primarily driven by variations in the NOX concentrations. The VOC source analysis results showed that the contributions of gasoline vehicle exhaust and diesel engine exhaust (mobile source emissions) were significantly greater than those of the other sources, accounting for 20.8% and 16.5% of the total VOC emissions, respectively. This study highlights the crucial role of mobile source emission control in mitigating O3 pollution. Furthermore, prioritizing the control of VOC emission sources with minimal NOX contributions is highly recommended within the VOC-limited regime. [ABSTRACT FROM AUTHOR]

Accurately measuring the combustion and destruction removal efficiency of flaring is important when accounting for methane emissions from oil and gas production. Despite this, the amount of experimental data from full-size flares is limited, especially for flares built without air or steam assistance. The use of a single destruction value of 98% is commonly applied. In this paper, we present new empirical measurements of flare efficiency using three common flare designs employed in upstream applications. Combustion products were analyzed using an extractive sampling method. The results demonstrate that whilst destruction efficiencies in excess of 98% are achievable, if the gas composition falls below a critical heating value of ~300 BTU/scf, the efficiency deteriorates leading to elevated methane emissions. This is further complicated by accurately measuring the flow of combustible gas and the impact of crosswinds. In an operational setting, continuous tracking of flare conditions is therefore a key resource in reducing methane emissions but further work is required to standardize how continuous performance tracking is evaluated if such measurements are to attain full traceability. [ABSTRACT FROM AUTHOR]

Perylene diimides (PDIs) have received considerable attention as a versatile class of functional dyes owing to their flexible reaction sites and remarkable stability. Recent advances have enhanced our understanding of the fluorescence and photothermal conversion properties of PDI molecules. The interplay between radiative and nonradiative transitions controls the emission and heat generation processes in these molecules. This comprehensive overview summarizes the recent strategies for manipulating the structures of PDI molecules for fluorescence and photothermal conversion applications. Additionally, challenges and potential solutions associated with the usage of fluorescent and photothermal PDI molecules are discussed. [ABSTRACT FROM AUTHOR]

In present, activated carbon (AC) pellets that are commonly prepared by petroleum-based binders have been used to control NO x , SO x , and volatile organic compounds (VOCs) emissions in the iron/steel industry. However, the use of petroleum-based binders leads to great challenges toward sustainability and environment. Alternatively, lignin as a natural bio-binder derived from biomass and organic waste can act as a potential additive for preparing AC pellets. Therefore, in this study, pinewood sawdust was initially fractionated into crude cellulose and lignin by organosolv fractionation method at 90–120 °C for 180 min in an acetic acid/formic acid/water mixed solvent of 3/5/2, 3/6/1, and 5/4/1, vol%/vol%/vol%. Afterward, the fractionated crude lignin was used as bio-additive to substitute 50 wt% of petroleum-derived phenol to synthesize phenol-formaldehyde resole resins (PLPF) and compared with those prepared using 100% petroleum-derived phenol resole resins (PF). PLPF and PF resins were further fabricated to AC pellets by thermal treatment/curing at 150 °C and different loadings of resins (i.e., 10–50 wt%), followed by carbonization at 400 and 700 °C. In the fractionation, it was found that temperature played a role in determining the yield and purity of crude cellulose and lignin, while the effect of solvent composition was insignificant. PLPF resins (loading of 50 wt%)-based AC pellets obtained from thermal treatment at 150 °C followed by carbonization at 400 °C showed a relatively higher compressive strength, which meets the national standard and could ensure their uses as an emission control method in the iron/steel industry. Overall, it can be concluded that lignin-derived from woody biomass by organosolv fractionation in acetic acid/formic acid/water mixture is an alternative bio-binder to prepare AC pellets for emission control at high temperatures. [ABSTRACT FROM AUTHOR]

A high percentage of the world's population lives in areas where air pollutant concentrations exceed the World Health Organization guidelines. This work aims to develop and test, a high-resolution multi-scale air pollution modelling system by integrating a set of adequate tools. This system is able to provide detailed air pollutant concentrations in urban areas and support air quality management strategies through a better identification of different atmospheric processes. It also allows furthering the design and assessment of air pollution control measures for a specific area. To evaluate its performance and suitability, the system was applied to the Macau Special Administrative Region (SAR), China, one of the most densely populated areas on earth, during a winter period when this area is affected by high levels of Particulate Matter (PM). Although the developed system tends to underestimate the PM concentrations, it revealed a good performance in reproducing the temporal and spatial air pollution patterns. Several exceedances of the Chinese air quality standards were calculated and high population exposure to PM pollution was estimated. The tested urban atmospheric emission reduction scenarios have shown air quality improvements, indicating that emission reduction measures at urban level should focus on the domestic sector. However, it is crucial to implement joint pollution prevention strategies with neighbouring regions to improve the air quality in Macau SAR. The approach developed in this work can support policymakers in defining new strategies to reduce atmospheric pollution in urban areas. [ABSTRACT FROM AUTHOR]

Hydrogen-diesel dual direct-injection (H2DDI) engines present a promising pathway towards cleaner and more efficient transportation. In this study, hydrogen split injection strategies were explored in an automotive-size single-cylinder compression ignition (CI) engine, with a focus on varying the injection timings and energy fractions. The engine was operated at an intermediate load with fixed combustion phasing through adjustments of pilot diesel injection timing. An energy substitution principle guided the variation in energy fraction between the two hydrogen injections and then diesel injection while keeping the total energy input constant. The findings demonstrate that early first hydrogen injection timings lead to characteristics indicative of premixed combustion, reflecting a high homogeneity of the hydrogen-air mixture. In contrast, hydrogen stratification levels were predominantly influenced by later second injection timings, with mixing-controlled combustion behaviour apparent for very late injections near top dead centre or when the second hydrogen injection held high energy fractions, which led to decreased nitrogen oxides (NO x : NO and NO 2) emissions. The carbon dioxide (CO 2) emissions did not show high sensitivity to the hydrogen split injection strategies, exhibiting about 77 % reduction compared to the diesel baseline due primarily to increased hydrogen energy fraction of up to 90 %. [Display omitted] • Use of conventional and single-hole capped injectors for hydrogen direct injection. • Hydrogen first direct injection with controlled premixed charge. • Hydrogen second direct injection for controlled charge stratification. • Hydrogen second injection effective for NO x emissions control. • About 77 % CO 2 reduction due to 90 % hydrogen but low sensitivity to split injections. [ABSTRACT FROM AUTHOR]

Random lasing with special structured light field has broad application prospects in various fields. However, the complex spatial modes of random lasing increase the difficulty of light field regulation and limit its practical application. Here, a vortex random lasing with dynamically tunable wavelength and orbital angular momentum is proposed based on the microfluidic channel. Different color random lasers are integrated into the same microfluidic channel for coarse control of the emission wavelengths from 462 to 685 nm by dynamically controlling the liquid flow. A special-shape cavity with a variable size of a gain region is further constructed to finely manipulate the emission wavelengths. Moreover, the vortex random lasing with tunable orbital angular momentum mode from −50 to 50 is realized. The results provide an outstanding strategy for generating the partially coherent vortex beams and may promote the practical applications of random lasers in the fields of sensing, imaging, and communication. [ABSTRACT FROM AUTHOR]

We report on the epitaxial growth, theoretical modeling, and structural as well as optical investigation of multi-layer, site-controlled quantum dots fabricated using the buried stressor method. This deterministic growth technique utilizes the strain from a partially oxidized AlAs layer to induce site-selective nucleation of InGaAs quantum dots. By implementing strain-induced spectral nano-engineering, we achieve spectral control of emission and a local increase in the emitter density. Furthermore, we achieve a threefold increase in the optical intensity and reduce the inhomogeneous broadening of the ensemble emission by 20% via stacking three layers of site-controlled emitters, which is valuable for using the SCQDs as a gain medium in microlaser applications. Our optimization of site-controlled growth of quantum dots enables the development of high-β microlasers with increased confinement factor. [ABSTRACT FROM AUTHOR]

This study delves into the impact of electric turbochargers on fuel efficiency and emissions in ethanol-gasoline blends. Informed by relevant literature, the research zeroes in on the positive influence of electric turbochargers, emphasizing their role in reducing fuel consumption and emissions while also addressing the trade-off between flame characteristics and NOx emissions. The experimental focus is on the injection modification of a single cylinder, with samples including engines equipped with and without an electric turbocharger. Statistical analysis utilizing percentage-based methods reveals that this technology leads to a substantial 94% reduction in CO emissions at idle speed, a 49% decrease in HC emissions at idle speed, and a 10% increase in CO2 at idle speed. Additionally, it also results in a notable 16.04% reduction in fuel consumption at 40 km/h. These outcomes underscore the potential of electric turbochargers to enhance automotive efficiency and sustainability while acknowledging the trade-off that necessitates further exploration for optimal emission control. The research provides concrete insights for refining electric turbocharger technology and optimizing its practical application. [ABSTRACT FROM AUTHOR]

Urgent emission reduction and community adaptation efforts are necessary to avert catastrophic climate-change harms. To assess our nation's progress toward such efforts, this Article develops a comprehensive structural analysis of U.S. climate policy at the federal, state, and local levels. It observes that current climate policies reflect disparate federal, state, and local strategies around emissions regulation, emission reduction subsidies, adaptation, and liability approaches. The Article then analyzes the dynamics between federal, state, and local strategies in these policy areas. This examination leads to some surprising conclusions. Under current policy alignments, further emission regulation measures do not appear to be realistic policy options. Though such regulatory measures have long been considered the most efficient climate interventions, this analysis suggests they have little near-term prospect for further deployment. Rather, current dynamics among the states and federal government indicate that previously second- and third-choice policies, like subsidies and liability measures, have greater potential for expansion. Thus, these less-favored policy approaches may represent the best hopes for pressing emission reduction efforts. Further, the analysis suggests that while most climate adaptation policy is implemented at the local level, federal adaptation policies require the more immediate attention. Because federal adaptation policies reflect a deferential funding strategy, where the federal government attempts to match support with state and local policy preferences, altering federal programs to better recognize state and local choices will enhance adaptation efforts at all levels of government. [ABSTRACT FROM AUTHOR]

Volatile organic compounds (VOCs) are major ingredients of photochemical smog. It is essential to know the spatial and temporal variation of VOC emissions. In this study, we used the Positive Matrix Factorization (PMF) model for VOC source apportionment in Mexico City. We first analyzed a data set collected during the ozone season from March–May 2016. It includes 33 VOCs, nitrogen oxide (NO), nitrogen dioxide (NO2), the sum of nitrogen oxides (NOx), carbon monoxide (CO), sulfur dioxide (SO2) and particle matter with a diameter < 1 μm (PM1). Another PMF analysis focused only on VOC data obtained in the month of May between the years 2016, 2017, 2018, 2021, and 2022 to gain insights into interannual variations. While the use of fossil fuel through combustion and evaporation continues to be major fraction in Mexico City, additional sources could be identified. Apart from biogenic sources which become more important closer to the end of the ozone season, a second natural emission factor termed "geogenic", was identified. Overall, anthropogenic sources range between 80–90%. Diurnal plots and bivariate plots show the relative importance of these emission source factors on different temporal and spatial scales, which can be applied in emission control policies for Mexico City. [ABSTRACT FROM AUTHOR]

Five typical in-use city buses in Tangshan with different emission standards, fuel power types, and emission control technology routes were selected as the research objects. PEMSs (Portable Emissions Measurement Systems) and OBD (On-Board Diagnostic) remote monitoring technologies were used to conduct research on actual road conditions and emission characteristics. The research aimed to analyze the driving characteristics of different power types of bus engines and after-treatment systems, as well as their impact on emissions. The results indicated that the actual road driving is mainly in the urban and suburban areas of the local region. Additionally, the VSP (Vehicle Specific Power) was found to be distributed in the low- and medium-speed range of mode Bin0~Bin24. The emission rates of each pollutant showed an increasing trend with the increase in VSP. THC and NOx emissions of CNG and LNG buses are significantly higher than those of gas–electric hybrid buses. However, the PM emissions are lower. Therefore, it is necessary to strengthen the NOx emission control of CNG and LNG buses. With the improvement in emission standards and the use of hybrid technology, CO2 and NOx emissions of China IV buses can be reduced by 13% and 53.5% compared with China III buses of the same tonnage. The CO2 and NOx emissions of China V buses using natural gas combustion and an electric mixture are 20% and 18.8% lower than those of China V buses of the same tonnage using only natural gas. In the actual operation of the diesel–electric hybrid bus equipped with the SCR (Selective Catalytic Reduction) system, the working time of the engine is about 35.5 ± 5%, and the working time of the SCR system only accounts for 65.5 ± 12%. The low working conditions of the SCR system and the low temperature of SCR system are the reasons for the high NOx concentration at the rear end of the SCR system when the hybrid electric bus is running at low speeds. [ABSTRACT FROM AUTHOR]

This study combined the real-time monitoring and investigation of traffic flows to comprehensively analyze the road traffic flow and vehicle structure in downtown Beijing. A dynamic emission inventory of motor vehicle air pollutants in downtown Beijing in 2021 was established, and the impact of these emissions on air quality was simulated and quantified, and different emission reduction control scenarios were proposed to evaluate their environmental improvement effects and explore measures to mitigate the impact of pollution emissions. The results show that the high traffic flow and the structure of the motor vehicle emissions in downtown Beijing are the main causes of severe motor vehicle pollution. Monitoring data shows that traffic flow in central Beijing is dominated by small passenger vehicles, while the vehicle mix is better than in other regions, with 72.0% of vehicles meeting "National V" or higher emission standards. However, to achieve higher air quality goals, further reducing vehicle emissions is necessary. Based on dynamic traffic flow, the average daily emissions of nitrogen oxides (NO X), particulate matters(PM 2.5) and volatile organic compounds(VOC) from motor vehicles in central Beijing are 17.7 tons, 0.6 tons and 14.0 tons, respectively, accounting for 23.0% of the city's average daily motor vehicle emissions. If a zero-emission zone for motor vehicles were implemented in central Beijing, the annual average emission level of pollutants will be reduced by 10.4% to 21.0%. The designation of ultra-low emission zones for motor vehicles could be effective in improving the air quality in the center of Beijing. [Display omitted] [ABSTRACT FROM AUTHOR]

• Emission characteristics, OFP, and health risk of fugitive VOCs were characterized. • Chemical material industry was the major contributor to VOCs of fugitive emission. • Fugitive VOCs contributed significantly to the total OFP. • Non-cancer risks and cancer risks of fugitive VOCs were all above the safe level. Fugitive emission from industrial sources may result in ozone formation and health risk, while the exact contribution of this source remains incompletely understood. In this study, emission characteristics, ozone formation potential (OFP) and health risk of fugitive VOCs in 7 representative industries were investigated. Chemical material industry was the dominant contributor to VOCs of fugitive emission in comparison with other industries. The OFP of VOCs from fugitive emission was in the range of 1.45 × 103-3.98 × 105 µg/m3, with a higher value than that of organized emission in seven industries except for the coking industry and the chemical material industry, suggesting that fugitive VOCs should be taken into account while developing control strategies. Acetaldehyde, m,p -xylene, n-nonane, ethylene, vinyl chloridethe and other high OFP-contributing species were the major reactive species that should be targeted. Health risk assessment investigated non-cancer and cancer risks of fugitive VOCs in 7 industries were all above safe level (HR > 1 and LCR > 1 × 10−4), posing remarkable health threats to human health. OVOCs were the main contributor to non-cancer risk, while halohydrocarbons and aromatics contributed most to cancer risks, posing remarkable health threat on human health. Our findings highlighted the contribution of fugitive VOCs on ozone formation and health risk was underestimated, indicating which should be considered in emission control strategies of industrial sources. [Display omitted] [ABSTRACT FROM AUTHOR]

The "2+26" cities, suffering the most severe winter haze pollution, have been the key region for air quality improvement in China. Increasing prominent nitrate pollution is one of the most challenging environmental issues in this region, necessitating development of an effective control strategy. Herein, we use observations, and state-of-the-art model simulations with scenario analysis and process analysis to quantify the effectiveness of the future SO 2 -NO X -VOC-NH 3 emission control on nitrate pollution mitigation in "2+26" cities. Focusing on a serious winter haze episode, we find that limited NO X emission reduction alone in the short-term period is a less effective choice than VOC or NH 3 emission reduction alone to decrease nitrate concentrations, due to the accelerated NO X -HNO 3 conversion by atmospheric oxidants and the enhanced HNO 3 to NO 3 − partition by ammonia, although deep NO X emission reduction is essential in the long-term period. The synergistic NH 3 and VOC emission control is strongly recommended, which can counteract the adverse effects of nonlinear photochemistry and aerosol chemical feedback to decrease nitrate more. Such extra benefits will be reduced if the synergistic NH 3 and VOC reduction is delayed, and thus reducing emission of multiple precursors is urgently required for the effective control of increasingly severe winter nitrate pollution in "2+26" cities. [ABSTRACT FROM AUTHOR]

• The anthropogenic VOC emission inventory containing 129 sources for China in 2018 was established. • A source profile database was established based on localized detection and the latest research results. • The distributions of the OFP and SOAFP of various emission sources were discussed. • The VOC emission inventory in 2030 was predicted, and then the control routes for VOC emission sources in 2018 and 2030 were proposed, respectively. An evidence-based control strategy for emission reduction of VOC sources can effectively solve the regional PM 2.5 and O 3 compound pollution in China. We estimated the anthropogenic VOC emission inventory in China in 2018 and established a source profile database containing 129 sources based on localized detection and the latest research results. Then, the distribution of the ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAFP) for emission sources was analyzed. Moreover, priority control routes for VOC emission sources were proposed for different periods. Anthropogenic VOC emissions in China reached 27,211.8 Gg in 2018, and small passenger cars, industrial protective coatings, biomass burning, heavy trucks, printing, asphalt paving, oil storage and transportation, coking, and oil refining were the main contributors. Industrial protective coatings, small passenger cars, and biomass burning all contributed significantly to OFP and SOAFP. Priority in emission reduction control should be given to industrial protective coatings, small passenger cars, heavy trucks, coking, printing, asphalt paving, chemical fibers, and basic organic chemical sources over the medium and long term in China. In addition, the priority control route for VOC emission sources should be adjusted according to the variations in VOC emission characteristics and regional differences, so as to obtain the maximum environmental benefits. [Display omitted] [ABSTRACT FROM AUTHOR]

Coupled cavities are of interest as they expose qualitatively new effects, such as non-Hermitian properties, which are beyond the possibilities of individual cavities. Here, we investigate the coupling between two dielectric two-dimensional microdisk cavities and compare circular vs deformed (limaçon) resonator shapes as a function of their distance and address the effect of coupling on the far-field emission properties. We find that the asymmetric coupling characteristic for non-circular, deformed cavities induces non-Hermitian properties prominently evident in a mode-dependent chirality of the coupled cavity modes. We use an analytical model to explain our findings and reveal the direct connection between coupling asymmetry and the resulting sense of rotation of the coupled modes. While the overall far-field directionality remains robust for intercavity distances larger than two wavelengths, we observe enhanced and reversed emission for smaller distances even for only two coupled cavities. Our findings could prove useful for future applications, such as far-field emission control and sensing. [ABSTRACT FROM AUTHOR]

This study explores emissions regulation of a 3.5 kW single cylinder, direct injection, diesel engine fuelled with biogas and Mahua biodiesel. By varying the compression ratio from 17 to 18 with a step of 0.5, pilot fuel injection timing by 3° BTDC from 23° BTDC to 32° BTDC, and engine load from 20% to 100% with a step of 20%, the optimal operating conditions are determined using response surface methodology. At the optimum engine operating parameter settings of a 17.73 compression ratio, 26.71° BTDC pilot fuel injection timing, and 58.96% engine load, the optimum emissions are 42.89 ppm for NOx, 80.36 ppm for UHC, 4.23% Vol. for CO 2 , and 77.72 ppm for CO. Additionally, the study demonstrates a comparable brake thermal efficiency of 17.35% with 66.26% pilot fuel substitution, indicating biogas-biodiesel as a sustainable and renewable option for dual-fuel CI compression-ignition engines. • Running biogas biodiesel has resulted in a significant decrement in NOx emissions. • Alteration in compression ratio and injection timing lowered CO and HC emissions. • Maximum optimum attained pilot fuel substitution is 66.26%. • Maximum brake thermal efficiency obtained is of 17.35%. • Optimization attained with best goodness of fit range of 0.86–0.99. [ABSTRACT FROM AUTHOR]

Quantum dots (QDs) exhibit size-dependent optical properties, where both the absorption and fluorescence energy levels vary with QD size. However, this dependence results in a discontinuity of intrinsically accessible energy levels for the bandgap, posing challenges in achieving precise energy tuning within a specific range. Herein, we demonstrate emission energy control of QDs with identical absorption energy levels by manipulating the spatial arrangement of QDs within QD–polymer complexes through hydrophobic interactions. The phase behavior of the QD–polymer complexes was modulated by adjusting the mass fraction of hydrophilic and hydrophobic blocks in the block copolymer, utilizing two types of amphiphilic block copolymers and varying temperatures. The QDs were spontaneously trapped within the hydrophobic region of the polymer template in water, resulting in spherical, cylindrical, and vesicle structures of QD–polymer complexes, corresponding to spherical, cylindrical, and layered assemblies of QDs, respectively. Depending on the QDs' location within the QD–polymer complex, the surface area in contact with water varied, leading to different degrees of oxidation and, consequently, a change in the fluorescence energy level of QDs. This study introduces a novel method to fine tune the emission energy (<15 eV) of QDs by adjusting the polymer form factor without complicated procedures. [ABSTRACT FROM AUTHOR]

Metal halide perovskite quantum dots (PQDs) have emerged as promising materials due to their exceptional photoluminescence (PL) properties. A wide range of applications could benefit from adjustable luminescence properties, while preserving the physical and chemical properties of the PQDs. Therefore, post‐synthesis engineering has gained attention recently, involving the use of ion‐exchange or external stimuli, such as extreme pressure, magnetic and electric fields. Nevertheless, these methods typically suffer from spectrum broadening, intensity quenching or yield multiple bands. Alternatively, photonic antennas can modify the radiative decay channel of perovskites via the Purcell effect, with the largest wavelength shift being 8 nm to date, at an expense of fivefold intensity loss. Here, this work presents an optical nanoantenna array with polarization‐controlled quasi‐bound‐states‐in‐the‐continuum resonances, which can engineer and shift the photoluminescence wavelength over a ≈39 nm range and confers a 21‐fold emission enhancement of FAPbI3 perovskite QDs. The spectrum is engineered in a non‐invasive manner via lithographically defined antennas and the pump laser polarization at ambient conditions. This research provides a path toward advanced optoelectronic devices, such as spectrally tailored quantum emitters and lasers. [ABSTRACT FROM AUTHOR]

We demonstrate the use of copper arylamide complexes as efficient photoluminescent mechanophores to design deep-red/near-IR emissive polymers showing reversible changes in photoluminescence intensity in the red/near-IR region in response to mechanical stretching. The mechanoresponse was repeatable over 30 cycles, showing a measurable increase of photoluminescence intensity even at a small applied stress of ca. 0.01 MPa. We demonstrate the potential of using conformationally dynamic copper amide complexes as sensitive and reversible mechanophores for near-IR imaging; systematic control over the emission range was achieved using amide modification. [ABSTRACT FROM AUTHOR]

In 2023, the International Maritime Organization revised its greenhouse gas strategy, striving to reduce annual emissions from international shipping by at least 70% by 2040. The Mediterranean Sea will become an emission control area for sulphur oxides and particulate matter from May 2025, and the EU will include shipping in its Emission Trading System from 2024. Liquid natural gas is expected to become a cleaner marine fuel, but it alone cannot meet emission reduction goals. The cryogenic carbon capture process can separate CO2 from exhaust gases, compress it, and store it in a liquid state with high density. This study aims to integrate an energy balance equation model to analyse the energy exchange in the regasification process and identify potential areas for improvement and targeted solutions to enhance performance and comply with IMO emission regulations. Based on a mathematical model, the energy balances are calculated and yield the following results: steam heater (26,999 kW), R-290 preheater (5,837 kW), trim heater (3,290 kW), R-290 evaporator (13,322 kW), and LNG vaporiser (23,118 kW). A report also determined that within a temperature range between -56.6°C and 31°C and a pressure range of greater than 5.2 bar (absolute) and less than 74 bar (absolute), the CO2 is in a liquid phase. Due to CO2 density which fluctuates in liquid at 1032 kg/m³ and in solid phase at 1562 kg/m³ the physical condition is compatible with the storage stage of capture emission. [ABSTRACT FROM AUTHOR]

High-performance and low-cost emission characteristic prediction is very crucial for diesel engine design optimization and emission aftertreatment control and diagnosis. In this paper, a novel hybrid model that combines Convolutional Neural Network (CNN) and Gated Recurrent Unit Network (GRU) was proposed to predict the emission characteristic from diesel engines, encompassing CO, THC, CO2, NOx, exhaust temperature and exhaust pressure. Nine operating parameters from WHTC and WHSC cycles, including speed, torque, intake pressure, intake flow, intake temperature, oil pressure, fuel rate, oil temperature, water temperature, were considered as inputs. Firstly, the importance of each variable is evaluated by Random Forests algorithm to determine the optimal inputs for each emission characteristic parameter and reduce redundancy. Then the effect of different hyperparameters on the model performance was discussed in detail and PSO algorithm was used to obtain the optimal hyperparameters. Finally, the CNN-GRU hybrid model was assessed for its generalization and compared with ANN, LSTM and GRU models. The result demonstrates that the CNN-GRU hybrid model with PSO optimization has excellent prediction performance in either the training dataset or the validation dataset. The average value of R² is 0.993 in the training dataset and 0.985 on the validation dataset. In the test dataset, the average R² is 0.961, showing a minor decrease of 3.19% and 2.47% compared to the training and validation dataset, respectively. This indicates that the CNN-GRU hybrid model has strong generalization ability. Compared with other algorithms in the test dataset, the CNN-GRU hybrid model exhibits better comprehensive performance, with the average R² value exceeding that of ANN, LSTM and only GRU by 5.96%, 2.69% and 3.23%, respectively. [ABSTRACT FROM AUTHOR]

Perceptron models have become integral tools for pattern recognition and classification problems in engineering fields. This study envisioned implementing artificial neural networks to forecast the performance of a mini-spray dryer for desulfurization activities. This work adopted k-fold cross-validation, a rigorous technique that evaluates model performance across multiple data segments. Several ANN models (21) were trained on data obtained from sulfation conditions, including sulfation temperature (120 °C–200 °C), slurry pH (4–12), stoichiometric ratio (0.5–2.5), slurry solid concentration (6%–14%) as the feed input and sulfur capture as the response. Three hundred synthetic datasets generated using the Gaussian noise data augmentation underwent a 10-fold cross-validation process before simulation on neural networks triggered by the logsig and tansig activation functions. The computation accuracy was further evaluated by altering the number of hidden cells from 2 to 10. The ANN architectures were assessed using statistical metrics such as mean square error (MSE), root mean square error (RMSE), mean absolute percentage error (MAPE), and the coefficient of determination (R2) techniques. Overall, error estimation suggests cross-validation and data augmentation are critical in efficient neural network generalization. The logsig function trained with 10 hidden cells presented closer data articulation when mapped onto actual values. [ABSTRACT FROM AUTHOR]

Black carbon (BC) emissions from shipboard diesel engines are the next potentially important issue of interest to the International Maritime Organization (IMO) and are considered to have a significant impact on the climate environment and human health. However, theories and technologies regarding the mechanisms of black carbon formation, oxidizing and influencing factors, emission detection methods, and abatement techniques are still missing in science and engineering. This paper provides a comprehensive overview of relevant advances in international maritime regulations, the frontier theory on formation mechanisms, comprehensive physical and chemical properties, and the potential reduction measures and control measures of emissions. These results suggest that BC is produced in the combustion flame of fuel and is related to the nucleation as well as the formation of PAHs. It helps to understand the initial generation process of black carbon and reduce its emission by studying it in detail and revealing some key factors, including micromorphology, nanostructural features, surface functional groups, oxidizing activity, size distribution, and elemental composition. Further, an in-depth understanding of the complex characteristics of BC can also help to identify viable BC measurement techniques and instrumentation for marine engines, thereby enhancing emission regulation. Overall, extensive technology can reduce BC emissions from marine diesel engines by approximately 50%. The information contained in this report can be used as a significant reference to further explore the BC formation mechanism and develop exclusive BC emission control strategies. [ABSTRACT FROM AUTHOR]