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1.
Food Chem ; 374: 131727, 2022 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-34915372

RESUMO

In this study, surimi from golden pompanos was mixed with starch to form a surimi-starch system. The water properties, rheological properties, and three-dimensional (3D) printability of the surimi-starch were measured. Cluster analysis results showed that the 3D printability was closely related to the type and addition content of starch, and the water and rheological properties. The low-field nuclear magnetic resonance (LF-NMR) parameters were used to predict 3D printability using polynomial regression models. The correlation coefficients (R2) for 3D printing accuracy and stability were 0.88 and 0.93, and the root mean square error (RMSE) values were 0.20% and 4.59%, respectively. In the verification test, the R2 for the two models were 0.85 and 0.89, and the RMSE values were 0.20% and 1.06%, respectively. The nonlinear surface regression fitting exhibited superior predictive performance. Therefore, LF-NMR is a good non-destructive tool for quickly and accurately predicting the 3D printability of the surimi-starch systems.

2.
Food Chem ; 374: 131737, 2022 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-34920408

RESUMO

The effects of different liquid nitrogen freezing (LNF) temperatures (-35, -55, -75, -95, and -115 °C) on the freezing rate, physicochemical properties, and microstructure of golden pompano (Trachinotus ovatus) were evaluated in the present study. The results showed that the total freezing time of golden pompano was significantly shortened using LNF (P < 0.05). Compared with other freezing methods, the cooking loss and L* values (lightness) of -95 °C LNF golden pompano were significantly lower, the false-colour image was much redder and brighter, the loss and mobility of water in fish muscle were inhibited, the water holding capacity and hardness were higher, and the muscle microstructure was comparatively intact. Therefore, -95 °C LNF effectively shortened the freezing time and improved the muscle qualities of frozen golden pompano.

3.
Food Chem ; 371: 131046, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34537614

RESUMO

To investigate the 3D printability of surimi from golden pompano, the rheological properties, protein molecular structure, and 3D printability of food inks from every step of surimi processing were measured, and their correlations were analysed. The results showed that surimi from chopping (surimi-C), chopping with salt (surimi-CS) and setting (surimi-S) were suitable for 3D printing, among which surimi-CS had the best shape fidelity. The clustering analysis of variables revealed that the yield stress and AF could be used as indexes to characterize extrusion and deposition behaviour of surimi, respectively. The accuracy of 3D printing was affected by the extrusion property of the food ink, which was controlled by the ionic bond content. The stability of 3D printing was affected by the self-supporting capacity of the food ink, which was controlled by the hydrogen bond and hydrophobic interaction contents. The results provided theoretical guidance for developing 3D printing of surimi ingredients.


Assuntos
Tinta , Impressão Tridimensional , Animais , Peixes , Estrutura Molecular , Reologia
4.
Atmos Res ; 265: 1-11, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34857979

RESUMO

Fast and accurate prediction of ambient ozone (O3) formed from atmospheric photochemical processes is crucial for designing effective O3 pollution control strategies in the context of climate change. The chemical transport model (CTM) is the fundamental tool for O3 prediction and policy design, however, existing CTM-based approaches are computationally expensive, and resource burdens limit their usage and effectiveness in air quality management. Here we proposed a novel method (noted as DeepCTM) that using deep learning to mimic CTM simulations to improve the computational efficiency of photochemical modeling. The well-trained DeepCTM successfully reproduces CTM-simulated O3 concentration using input features of precursor emissions, meteorological factors, and initial conditions. The advantage of the DeepCTM is its high efficiency in identifying the dominant contributors to O3 formation and quantifying the O3 response to variations in emissions and meteorology. The emission-meteorology-concentration linkages implied by the DeepCTM are consistent with known mechanisms of atmospheric chemistry, indicating that the DeepCTM is also scientifically reasonable. The DeepCTM application in China suggests that O3 concentrations are strongly influenced by the initialized O3 concentration, as well as emission and meteorological factors during daytime when O3 is formed photochemically. The variation of meteorological factors such as short-wave radiation can also significantly modulate the O3 chemistry. The DeepCTM developed in this study exhibits great potential for efficiently representing the complex atmospheric system and can provide policymakers with urgently needed information for designing effective control strategies to mitigate O3 pollution.

5.
Sci Total Environ ; 806(Pt 4): 151459, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34742961

RESUMO

Fine particulate matter (PM2.5) and its constituents pose great threatens to public health. The spatial-temporal characteristics of some key chemical constituents, such as sulfate, nitrate, and especially toxic trace elements in China has remained unclear, limiting further studies on evaluating the associated public health. Here, we conduct a two-yearlong (2012 and 2015) air quality simulation by coupling localized emission inventory for primary air pollutants and trace elements with a modified CMAQ model in a domain of China and five urban agglomerations. Associated health burdens of PM2.5 and various toxic trace elements are assessed applying exposure assessment models. The model successfully reproduces air pollution situations. Significant spatial-temporal variations of PM2.5 and chemical constituents are observed, with higher concentrations mainly occurred in North China Plain (NCP), Fenwei Plain (FWP) and Sichuan-Chongqing Basin (SCB). All chemical constituents in PM2.5 show higher concentrations in winter except for sulfate. From 2012 to 2015, the annual averaged PM2.5 concentration and its constituents decreased by 3% -20% nationally and regionally. Smaller reductions of nitrate make PM2.5 pollution become nitrate-dominated, especially in winter. Approximately 0.28 million deaths related to PM2.5 in China are avoided, while the population affected by the cancer risks of Cr (VI) and arsenic has slightly increased from 2012 to 2015. Our findings could provide critical insights on the mitigation of air pollution, as well as benefit for epidemiological studies on air pollutants related health effects.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Poluentes Atmosféricos/análise , Poluição do Ar/análise , China , Monitoramento Ambiental , Material Particulado/análise
6.
Environ Sci Technol ; 2021 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-34962805

RESUMO

Serious ambient PM2.5 and O3 pollution is one of the most important environmental challenges of China, necessitating an urgent cost-effective cocontrol strategy. Herein, we introduced a novel integrated assessment system to optimize a NOx and volatile organic compound (VOC) control strategy for the synergistic reduction of ambient PM2.5 and O3 pollution. Focusing on the Beijing-Tianjin-Hebei cities and their surrounding regions, which are experiencing the most serious PM2.5 and O3 pollution in China, we found that NOx emission reduction (64-81%) is essential to attain the air quality standard no matter how much VOC emission is reduced. However, the synergistic VOC control is strongly recommended considering its substantially human health and crop production benefits, which are estimated up to 163 (PM2.5-related) and 101 (O3-related) billion CHY during the reduction of considerable emissions. Notably, such benefits will be greatly reduced if the synergistic VOC reduction is delayed. This study also highlights the necessity of simultaneous VOC and NOx emission control in winter while enhancing the NOx control in the summer, which is contrary to the current control strategy adopted in China. These findings point out the right pathways for future policy making on comitigating PM2.5 and O3 pollution in China and other countries.

7.
Environ Sci Technol ; 2021 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-34786936

RESUMO

The COVID-19 outbreak provides a "controlled experiment" to investigate the response of aerosol pollution to the reduction of anthropogenic activities. Here we explore the chemical characteristics, variations, and emission sources of organic aerosol (OA) based on the observation of air pollutants and combination of aerosol mass spectrometer (AMS) and positive matrix factorization (PMF) analysis in Beijing in early 2020. By eliminating the impacts of atmospheric boundary layer and the Spring Festival, we found that the lockdown effectively reduced cooking-related OA (COA) but influenced fossil fuel combustion OA (FFOA) very little. In contrast, both secondary OA (SOA) and O3 formation was enhanced significantly after lockdown: less-oxidized oxygenated OA (LO-OOA, 37% in OA) was probably an aged product from fossil fuel and biomass burning emission with aqueous chemistry being an important formation pathway, while more-oxidized oxygenated OA (MO-OOA, 41% in OA) was affected by regional transport of air pollutants and related with both aqueous and photochemical processes. Combining FFOA and LO-OOA, more than 50% of OA pollution was attributed to combustion activities during the whole observation period. Our findings highlight that fossil fuel/biomass combustion are still the largest sources of OA pollution, and only controlling traffic and cooking emissions cannot efficiently eliminate the heavy air pollution in winter Beijing.

8.
Sci Total Environ ; : 151609, 2021 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-34774945

RESUMO

High-emission vehicles (high emitters) likely have significantly higher nitrogen oxide and particle number (PN) emission factors compared to other vehicles. Effective identification of these vehicles in road traffic requires efficient and cost-effective instruments. In this study, a compact, cost-effective sensor platform was developed and evaluated in a field experiment. The platform was deployed on a roadside, and we measured pollutant concentrations in the exhaust plumes of four diesel trucks with various aftertreatment systems, cargo loads, and driving speeds. The sensor platform successfully measured carbon dioxide, PN, and nitric oxide (NO) concentrations, and the data were used to derive the plume-based emission factors of these pollutants. By considering both NO and PN emission factors, three diesel trucks with failed or outdated aftertreatment systems were successfully identified as potential high emitters. The NO emission factor obtained by the sensor platform was consistent with that of the benchmark portable emission measurement system. The sensor platform also effectively elucidated the differential influences of aftertreatment systems and driving conditions on emission factors. This pilot test demonstrates the feasibility of a sensor-based system for high emitter identification. Owing to its cost-effective and compact design, the proposed sensor platform has greater potential for mass networked deployment than regular-size instruments, thereby effectively supporting regulatory protocols for screening high emitters on public roads.

9.
Proc Natl Acad Sci U S A ; 118(42)2021 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-34635590

RESUMO

As the world's largest CO2 emitter, China's ability to decarbonize its energy system strongly affects the prospect of achieving the 1.5 °C limit in global, average surface-temperature rise. Understanding technically feasible, cost-competitive, and grid-compatible solar photovoltaic (PV) power potentials spatiotemporally is critical for China's future energy pathway. This study develops an integrated model to evaluate the spatiotemporal evolution of the technology-economic-grid PV potentials in China during 2020 to 2060 under the assumption of continued cost degression in line with the trends of the past decade. The model considers the spatialized technical constraints, up-to-date economic parameters, and dynamic hourly interactions with the power grid. In contrast to the PV production of 0.26 PWh in 2020, results suggest that China's technical potential will increase from 99.2 PWh in 2020 to 146.1 PWh in 2060 along with technical advances, and the national average power price could decrease from 4.9 to 0.4 US cents/kWh during the same period. About 78.6% (79.7 PWh) of China's technical potential will realize price parity to coal-fired power in 2021, with price parity achieved nationwide by 2023. The cost advantage of solar PV allows for coupling with storage to generate cost-competitive and grid-compatible electricity. The combined systems potentially could supply 7.2 PWh of grid-compatible electricity in 2060 to meet 43.2% of the country's electricity demand at a price below 2.5 US cents/kWh. The findings highlight a crucial energy transition point, not only for China but for other countries, at which combined solar power and storage systems become a cheaper alternative to coal-fired electricity and a more grid-compatible option.

10.
Environ Int ; 158: 106918, 2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34649048

RESUMO

BACKGROUND: Ambient and household air pollution are found to lead to premature deaths from all-cause or cause-specific death. The national lockdown measures in China during COVID-19 were found to lead to abrupt changes in ambient surface air quality, but indoor air quality changes were neglected. In this study, we aim to investigate the impacts of lockdown measures on both ambient and household air pollution as well as the short-term health effects of air pollution changes. METHODS: In this study, an up-to-date emission inventory from January to March 2020 in China was developed based on air quality observations in combination with emission-concentration response functions derived from chemical transport modeling. These emission inventories, together with the emissions data from 2017 to 2019, were fed into the state-of-the-art regional chemistry transport model to simulate the air quality in the North China Plain. A hypothetical scenario assuming no lockdown effects in 2020 was also performed to determine the effects of the lockdown on air quality in 2020. A difference-to-difference approach was adopted to isolate the effects on air quality due to meteorological conditions and long-term decreasing emission trends by comparing the PM2.5 changes during lockdown to those before lockdown in 2020 and in previous years (2017-2019). The short-term premature mortality changes from both ambient and household PM2.5 changes were quantified based on two recent epidemiological studies, with uncertainty of urban and rural population migration considerations. FINDINGS: The national lockdown measures during COVID-19 led to a reduction of 5.1 µg m-3 in ambient PM2.5 across the North China Plain (NCP) from January 25th to March 5th compared with the hypothetical simulation with no lockdown measures. However, a difference-to-difference method showed that the daily domain average PM2.5 in the NCP decreased by 9.7 µg m-3 between lockdown periods before lockdown in 2020, while it decreased by 7.9 µg m-3 during the same periods for the previous three-year average from 2017 to 2019, demonstrating that lockdown measures may only have caused a 1.8 µg m-3 decrease in the NCP. We then found that the integrated population-weighted PM2.5, including both ambient and indoor PM2.5 exposure, increased by 5.1 µg m-3 during the lockdown periods compared to the hypothetical scenario, leading to additional premature deaths of 609 (95% CI: 415-775) to 2,860 (95% CI: 1,436-4,273) in the short term, depending on the relative risk chosen from the epidemiological studies. INTERPRETATION: Our study indicates that lockdown measures in China led to abrupt reductions in ambient PM2.5 concentration but also led to significant increases in indoor PM2.5 exposure due to confined indoor activities and increased usages of household fuel for cooking and heating. We estimated that hundreds of premature deaths were added as a combination of decreased ambient PM2.5 and increased household PM2.5. Our findings suggest that the reduction in ambient PM2.5 was negated by increased exposure to household air pollution, resulting in an overall increase in integrated population weighted exposure. Although lockdown measures were instrumental in reducing the exposure to pollution concentration in cities, rural areas bore the brunt, mainly due to the use of dirty solid fuels, increased population density due to the large-scale migration of people from urban to rural areas during the Chinese New Year and long exposure time to HAP due to restrictions in outdoor movement.

11.
Environ Sci Technol ; 55(20): 13860-13868, 2021 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-34590832

RESUMO

This study developed an up-to-date and point-source-based inventory of mercury (Hg) releases to water in China by applying probabilistic release factors that combined industry removal efficiencies, reuse of reclaimed water, and receiving water types. In 2017, the national mercury release to water was estimated to be 50 (35-66) tons, in which 47%, 8%, 7%, and 25% were from nonferrous metal smelting, vinyl chloride monomer (VCM) production, coal-fired boilers, and domestic sewage, respectively. Approximately 95% of mercury was released to inland rivers, and the rest was discharged to lakes or coastal water. The significant sources were identified based on their mercury releases to water. The control of mercury release to water in China shall focus on zinc smelting plants, municipal sewage treatment plants, and the VCM production process. For zinc smelting plants, China can tighten the limit of mercury concentration in discharged wastewater and combine Hg-catcher device in traditional integrated treatment. For municipal sewage treatment plants and the VCM production process, promoting processes of Hg-free production can reduce mercury inputs at the source. Our study provides insights for other parties to identify the relevant sources of mercury release to water and to conduct control measures, so as to promote the global convention implementation.


Assuntos
Poluentes Atmosféricos , Mercúrio , Poluentes Atmosféricos/análise , China , Carvão Mineral/análise , Monitoramento Ambiental , Mercúrio/análise , Rios , Água
12.
Environ Sci Technol ; 55(19): 12818-12830, 2021 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-34538053

RESUMO

Airborne trace elements (TEs) pose a notable threat to human health due to their toxicity and carcinogenicity, whereas their exposures and associated health risks in China remain unclear. Here, we present the first nationwide assessment of spatiotemporal exposure to 11 TEs in China by coupling a bottom-up emission inventory with a modified CMAQ model capable of TE simulation. Associated health risks of 11 TEs are then evaluated using a set of risk assessment models. Our results show that the CMAQ model could reasonably reproduce the spatiotemporal variations of 11 TEs in China compared to observations. We find significant but spatiotemporal-heterogeneous cancer risks associated with high-level exposure of TEs in China. Gridded cell concentrations of hexavalent chromium, arsenic, and nickel in eastern and central China usually exceed China's air quality standard limits, resulting in significant cancer risks that affected over 85% of the entire population in China in 2015. National annual mean population-weighted concentrations of 11 TEs decrease by 9.8-35.6% from 2012 to 2015, largely attributed to emission reduction from coal combustion. Our study provides critical insights for policymakers to implement stricter measures to alleviate health burdens and benefit relevant epidemiological research on airborne TEs.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Oligoelementos , Poluentes Atmosféricos/análise , China , Carvão Mineral/análise , Monitoramento Ambiental , Humanos , Oligoelementos/análise
13.
Environ Sci Technol ; 2021 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-34347472

RESUMO

The 1.5 °C pathways initially promoted by the challenges presented by climate change could bring substantial air quality-related benefits. However, since there is a lack of comprehensive assessment on emissions of air pollutants, meteorology, air quality, and heatwave occurrences under different climate goals, how significant the clean air cobenefits compared with the direct climate-related impact is uncertain. In this study, we assess the cobenefits of 1.5 °C pathways for air quality in China by linking multiple shared socioeconomic pathways, ensembling simulations of regional climate-air quality dynamic downscaling and an air pollution and climate-related health assessment model, and compare different kinds of benefits: the health benefits from direct slowing climate (reduced heatwaves) versus the health cobenefits from air quality improvement (the improved air quality from reduced air pollutants versus meteorological changes). The benefit of reduced air pollution emissions associated with sustainable development under 1.5 °C pathways dominated the overall impact, which could avoid 1 589 000 PM2.5-related and 526 000 O3-related deaths in 2050. Correspondingly, the impact of changed meteorology on air quality would avoid additional 8000 PM2.5-related deaths in 2050 under 1.5 °C pathways yet would lead to 22 000 O3-related deaths. Also, the heatwave-related deaths could be avoided by 7000. The substantial anthropogenic emission reduction cobenefits of 1.5 °C pathways in improving air quality significantly exceed the direct climate (heatwave-related) benefits and completely offset the impact of meteorological changes' impact on air pollution under climate change.

14.
Sci Total Environ ; 791: 148158, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34412397

RESUMO

The escalating concerns regarding air pollution problems surrounding port cities have attracted much research attention. The Port of Shenzhen is one of the busiest container ports worldwide, only third to Shanghai and Singapore globally. However, 70% of the freight transportation demand is satisfied via on-road trucks, leading to serious traffic congestion, road accidents and air pollution issues in the city of Shenzhen. This study aims to assess the environmental benefits of modal shift of port-connecting freight transportation by increasing the use of rail and waterborne systems in Shenzhen. To evaluate the environmental benefits of the multimodal transportation strategy in 2025, we employed traffic datasets with a high spatial resolution and a transportation demand model to establish emission inventories and applied them in air quality simulations. Our results indicate that the implementation of multimodal transportation systems could notably reduce the truck volume along major freight corridors, except for roads adjacent to the planned inland ports. The freight traffic activities along the major freight corridors are reduced by nearly 70% over the original freight volume, resulting in a drastic reduction in the emission intensity. Under the most progressive policy-enhanced strategy (PPP) scenario, the total well-to-wheel (WTW) NOX, fine particulate matter (PM2.5) and CO2 emissions could be reduced by 8881 t, 104.8 t and 688 × 103 t, respectively. The NO2 concentration in traffic-intensive areas could be reduced by 5 µg/m3, and the 8-h maximum O3 concentration could be reduced by 0.34 µg/m3 on the average (up to 1.1 µg/m3 in certain areas). Our research indicates that a shift from traditional road transport to cleaner railway and waterway transport could deliver transportation and environmental benefits to port cities.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Poluentes Atmosféricos/análise , Poluição do Ar/análise , China , Melhoria de Qualidade , Água
15.
Environ Pollut ; 289: 117833, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34332166

RESUMO

The Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) is the first programme to tackle carbon dioxide (CO2) emissions from a single industry at the global level, to realize the carbon-neutral growth of international flights from 2020 onwards. However, the COVID-19 pandemic has caused a drastic decline in the global aviation industry. The International Civil Aviation Organization (ICAO) has adjusted the CORSIA by removing 2020 emissions from the baseline, which now will only be based on 2019 emissions. We estimate that the total carbon dioxide (CO2) emissions from global international flights decreased by 70 % from February to July 2020 compared to those in 2019. Our analysis suggests that the annual CO2 emissions from international flights during the pilot stage of CORSIA (2021-2023) will be far below the revised baseline even if the global aviation industry could embrace an optimistic recovery. The major airline companies will have very limited motivations due to the CORSIA scheme to implement mitigation actions proactively. Therefore, more progressive actions are needed to align the industry recovery of global aviation and climate change mitigation during the post-COVID-19 period.


Assuntos
Aviação , COVID-19 , Corsiaceae , Dióxido de Carbono/análise , Humanos , Motivação , Pandemias , SARS-CoV-2
16.
Sci Data ; 8(1): 171, 2021 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-34257314

RESUMO

China has committed to reaching carbon neutrality by 2060, which will require a drastic cut in greenhouse gas (GHG) emissions from all sectors, including those from agricultural activities. A comprehensive, long-term, and spatially-precise profile of agricultural GHG emissions can help to accurately understand drivers of historical emissions and their implications for future mitigation. This study constructs province-level agricultural GHG emissions in China from 1978 to 2016. It considers primary and secondary emissions from a full range of agricultural activities related to crop farming, including crop residue open burning, rice cultivation, cropland change, cropland emissions, machinery use, nitrogen fertilizer production, and pesticide production. Annual or interpolated activity data from official sources and the latest emission factors available for China were adopted in this study. The data can be used in spatial and temporal analysis of emissions from cropping systems as well as the design of mitigation strategy in China.


Assuntos
Carbono/análise , Produção Agrícola , Produtos Agrícolas , Gases de Efeito Estufa , China , Fertilizantes , Oryza
17.
Huan Jing Ke Xue ; 42(7): 3091-3098, 2021 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-34212634

RESUMO

The COVID-19 pandemic has endangered human health and production since 2019. As an emerging disease caused by SARS-CoV-2, its potential transmissibility via aerosols has caused heated debate. This work summarizes the current research findings on virus aerosol generation, aerodynamic properties, and environmental influencing factors on their survivability in order to elucidate coronavirus transmission via aerosols. The occurrence and distinction of SARS-CoV-2, SARS-CoV-1, and MERS-CoV in real atmospheric environments are summarized. The deficiencies of existing research and directions for necessary future research on confirming the airborne transmission mechanism of coronavirus as well as the need for multidisciplinary research are discussed.


Assuntos
COVID-19 , Pandemias , Aerossóis , Humanos , SARS-CoV-2
18.
Food Sci Nutr ; 9(6): 2985-2999, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34136165

RESUMO

The three-dimensional (3D) printing properties of pure shrimp surimi are poor and require improvement via the addition of other materials. The effects of the different amounts of potato starch, corn starch, tapioca starch, and cross-linked starch (CLS) (0%, 3%, 6%, or 9%, respectively) on the 3D printing properties and material properties of white shrimp (Litopenaeus vannamei) surimi were evaluated in the present study. The results showed that the apparent viscosity, G', and G'' of the samples were increased by adding 6% CLS, making it easy to extrude the sample from the nozzle and resulting in an improvement in the printing accuracy. In addition, after adding 6% CLS, the hardness, adhesiveness, and springiness of the sample were increased, which assist with maintaining the shape of the printed material and improve the printing stability of the sample. Moreover, the water holding capacity of shrimp surimi increased as a result of the addition of 6% CLS. In summary, 6% CLS can improve the material properties of shrimp surimi and make it more suitable for 3D printing.

20.
Proc Natl Acad Sci U S A ; 118(26)2021 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-34155113

RESUMO

The large fluctuations in traffic during the COVID-19 pandemic provide an unparalleled opportunity to assess vehicle emission control efficacy. Here we develop a random-forest regression model, based on the large volume of real-time observational data during COVID-19, to predict surface-level NO2, O3, and fine particle concentration in the Los Angeles megacity. Our model exhibits high fidelity in reproducing pollutant concentrations in the Los Angeles Basin and identifies major factors controlling each species. During the strictest lockdown period, traffic reduction led to decreases in NO2 and particulate matter with aerodynamic diameters <2.5 µm by -30.1% and -17.5%, respectively, but a 5.7% increase in O3 Heavy-duty truck emissions contribute primarily to these variations. Future traffic-emission controls are estimated to impose similar effects as observed during the COVID-19 lockdown, but with smaller magnitude. Vehicular electrification will achieve further alleviation of NO2 levels.


Assuntos
Poluição do Ar/análise , COVID-19/epidemiologia , Aprendizado de Máquina , Modelos Teóricos , Transportes , Poluentes Atmosféricos/análise , Algoritmos , Eletricidade , Humanos , Material Particulado/análise , Emissões de Veículos
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