Porosity Characterization of Thermal Barrier Coatings by Ultrasound with Genetic Algorithm Backpropagation Neural Network

Porosity is considered as one of the most important indicators for the characterization of the comprehensive performance of thermal barrier coatings (TBCs). In this study, the ultrasonic technique and the artificial neural network optimized with the genetic algorithm (GA_BPNN) are combined to develop an intelligent method for automatic detection and accurate prediction of TBCs’s porosity. A series of physical models of plasma-sprayed ZrO2 coating are established with a thickness of 288 μm and porosity varying from 5.71% to 26.59%, and the ultrasonic reflection coefficient amplitude spectrum (URCAS) is constructed based on the time-domain numerical simulation signal. The characteristic features f1,f2,Amax,ΔA of the URCAS, which are highly dependent on porosity, are extracted as input data to train the GA_BPNN model for predicting the unknown porosity. The average error of the prediction results is 1.45%, which suggests that the proposed method can achieve accurate detection and quantitative characterization of the porosity of TBCs with complex pore morphology

Lifestyle Behaviors and Cardiometabolic Diseases by Race and Ethnicity and Social Risk Factors Among US Young Adults, 2011 to 2018

Background Cardiometabolic health has been worsening among young adults, but the prevalence of lifestyle risk factors and cardiometabolic diseases is unclear. Methods and Results Adults aged 18 to 44 years were included from the National Health and Nutrition Examination Survey, 2011 to 2018. Age‐standardized prevalence of lifestyle risk factors and cardiometabolic diseases was estimated overall and by demographic and social risk factors. A set of multivariable logistic regressions was sequentially performed by adjusting for age, sex, social risk factors, and lifestyle factors to determine whether racial and ethnic disparities in the prevalence of cardiometabolic diseases may be attributable to differences in social risk factors and lifestyle factors. Appropriate weights were used to ensure national representativeness of the estimates. A total of 10 405 participants were analyzed (median age, 30.3 years; 50.8% women; 32.3% non‐Hispanic White). The prevalence of lifestyle risk factors ranged from 16.3% for excessive drinking to 49.3% for poor diet quality. The prevalence of cardiometabolic diseases ranged from 4.3% for diabetes to 37.3% for dyslipidemia. The prevalence of having ≥2 lifestyle risk factors was 45.2% and having ≥2 cardiometabolic diseases was 22.0%. Racial and ethnic disparities in many cardiometabolic diseases persisted but were attenuated after adjusting for social risk factors and lifestyle factors. Conclusions The prevalence of lifestyle risk factors and cardiometabolic diseases was high among US young adults and varied by race and ethnicity and social risk factors. Racial and ethnic disparities in the prevalence of cardiometabolic diseases were not fully explained by differences in social risk factors and lifestyle factors

Chemerin-9 Attenuates Experimental Abdominal Aortic Aneurysm Formation in ApoE−/− Mice

Chronic inflammation plays an essential role in the pathogenesis of abdominal aortic aneurysm (AAA), a progressive segmental abdominal aortic dilation. Chemerin, a multifunctional adipocytokine, is mainly generated in the liver and adipose tissue. The combination of chemerin and chemokine-like receptor 1 (CMKLR1) has been demonstrated to promote the progression of atherosclerosis, arthritis diseases, and Crohn’s disease. However, chemerin-9 acts as an analog of chemerin to exert an anti-inflammatory effect by binding to CMKLR1. Here, we first demonstrated that AAA exhibited higher levels of chemerin and CMKLR1 expression compared with the normal aortic tissues. Hence, we hypothesized that the chemerin/CMKLR1 axis might be involved in AAA progression. Moreover, we found that chemerin-9 treatment markedly suppressed inflammatory cell infiltration, neovascularization, and matrix metalloproteinase (MMP) expression, while increasing the elastic fibers and smooth muscle cells (SMCs) in Ang II-induced AAA in ApoE−/− mice. This demonstrated that chemerin-9 could inhibit AAA formation. Collectively, our findings indicate a potential mechanism underlying AAA progression and suggest that chemerin-9 can be used therapeutically

Study on Emission Characteristics and Emission Reduction Effect for Construction Machinery under Actual Operating Conditions Using a Portable Emission Measurement System (Pems)

With the acceleration of urban construction, the pollutant emission of non-road mobile machinery such as construction machinery is becoming more and more prominent. In this paper, a portable emissions measurement system (PEMS) tested the emissions of eight different types of construction machinery under actual operating conditions and was used for idling, walking, and working under the different emission reduction techniques. The results showed that the pollutant emission of construction machinery is affected by the pollutant contribution of working conditions. According to different emission reduction techniques, the diesel oxidation catalyst (DOC) can reduce carbon monoxide (CO) by 41.6–94.8% and hydrocarbon (HC) by 92.7–95.1%, catalytic diesel particulate filter (CDPF) can reduce particulate matter (PM) by 87.1–99.5%, and selective catalytic reduction (SCR) using urea as a reducing agent can reduce nitrogen oxides (NOx) by 60.3% to 80.5%. Copper-based SCR is better than vanadium-based SCR in NOx reduction. In addition, the study found that when the enhanced 3DOC + CDPF emission reduction technique is used on forklifts, DOC has a “low-temperature saturation effect”, which will reduce the emission reduction effect of CO and THC. The use of Burner + DOC + CDPF emission reduction techniques and fuel injection heating process will increase CO’s emission factors by 3.2–3.5 and 4.4–6.7 times compared with the actual operating conditions

A synthesis of research needs for improving the understanding of atmospheric mercury cycling

This synthesis identifies future research needs in atmospheric mercury science, based on a series of review papers, as well as recent developments in field data collection, modeling analysis, and emission assessments of speciated atmospheric mercury. Research activities are proposed that focus on areas that we consider important. These include refinement of mercury emission estimations, quantification of dry deposition and air-surface exchange, improvement of the treatment of chemical mechanisms in chemical transport models, increase in the accuracy of oxidized mercury measurements, better interpretation of atmospheric mercury chemistry data, and harmonization of network operation. Knowledge gained in these research areas will significantly improve our understanding of atmospheric cycling from local to global scales

Carbon neutrality and clean air acts can enable China to meet the Minamata Convention goals with substantial cost savings

China faces the concurrent challenges of carbon dioxide (CO2) and toxic mercury (Hg) emissions from coal combustion, with implications for environmental and human health. To address these problems, China has implemented carbon neutrality targets and air pollution controls and signed the Minamata Convention. However, how to best leverage these measures for optimal outcomes (i.e., effectively reduce emissions and pollution with the least cost) remains elusive. Here we examined the best-practice portfolio of climate, air pollution, and Hg reduction policies via an energy-environment-economic integrated assessment model. We found that the most cost-effective solution to simultaneously address these issues is coupling carbon neutrality strategies with clean air policies, which can further save 384 million Chinese yuan (CNY) in Hg abatement in 2060. Furthermore, carbon neutrality measures alone can achieve near-zero Hg emissions, whereas Hg policies will only achieve about one-third of the carbon neutrality target. These findings provide practical lessons to cost-effectively address multiple climate and pollution issues, especially for emerging economies that face similar challenges

Formation of secondary organic aerosol from wildfire emissions enhanced by long-time ageing

International audienc

Photochemical Reduction of Particle Bound Mercury in Atmospheric Aerosol Water

Particle bound mercury (PBM) deposition on the Earth’s surface threatens biota and humans. The photoreduction of PBM competes with deposition and thereby modifies global mercury cycling; yet, its pathway and mechanism remain poorly understood. Herein, we reveal the photoreduction process of PBM by comprehensively using field observation, mercury stable isotope analysis, and controlled experiment. We found the Δ199Hg values in wet haze episodes (0.34‰ ± 0.30‰) were significantly higher than those in clean periods (0.14‰ ± 0.19‰), majorly attributed to the elevated aerosol water content (AWC), which shifts the aerosol phase from the solid state to the liquid state, promoting soluble HgCl2 and HgBr2 photoreduction reactions. The carboxyl functional groups of water-soluble organic carbon (WSOC) were further identified as the crucial compounds that induce PBM photoreduction, whose reaction rates were ∼2 times higher than those of phenol and ketone ligands and 3–6 times higher than those observed in other atmospheric aqueous phases. Considering the ubiquitously distributed carboxyl ligands and significant positive Δ199Hg signals in the atmospheric aqueous phases, the PBM photoreduction mediated by carboxyl ligands is highlighted to significantly influence global mercury transformations, regional depositions, and isotopic compositions of atmospheric mercury pools