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21 pages, 1236 KiB

Open AccessArticle

Associations between Recognition and Behaviors Regarding the Use, Washing and Management of Firefighting Protection Suits and Public Health Awareness of Occupational Exposure Risks among Firefighters

by Soo Jin Kim and Seunghon Ham

Fire 2024, 7(5), 156; https://doi.org/10.3390/fire7050156 (registering DOI) - 29 Apr 2024

Abstract

The firefighting protective suits (FPSs) of firefighters at fire scenes affect their health and safety. However, the association between firefighters’ health awareness of occupational exposure risks and the FPS use, washing and management remains unclear. Therefore, this study aimed to evaluate the association [...] Read more.

The firefighting protective suits (FPSs) of firefighters at fire scenes affect their health and safety. However, the association between firefighters’ health awareness of occupational exposure risks and the FPS use, washing and management remains unclear. Therefore, this study aimed to evaluate the association between firefighters’ health awareness of occupational exposure risks and their recognition, behaviors regarding the use, washing and management of FPSs. This study design is a cross-sectional study and used a web-based survey of the Seoul Metropolitan Government’s electronic survey system. The survey was conducted on metropolitan firefighters performing shift work in charge of fire and rescue work for 21 days from 1 to 22 April 2019, with 1097 (40.3%) respondents. Characteristics of FPS use, washing and management and the association between thoughts and behaviors thereof and health awareness of occupational exposure risks were evaluated. Data of 1097 firefighters were analyzed using the SAS 9.4 statistical package, chi-square test and logistic regression analysis. Firefighters’ fire scene awareness rate of possible carcinogens was 94.4%. There was an association between public health thinking of occupational exposure risks and the correct use of an FPS for one’s own safety (AOR 1.97. 95% CI 1.02–3.80). However, no association was shown between correct FPS use (AOR 1.49, 95% CI 0.48–4.59), washing (AOR 2.50, 95% CI 0.93–6.68) and management (AOR 1.38, 95% CI 0.75–2.50) behaviors. This study analyzed the relationship between the use, washing and management of personal protective equipment called firefighting clothing and firefighters perceived occupational exposure risks. This study found an association between the health awareness of occupational exposure risks and recognition of the correct use of FPSs at fire scenes but not between using, washing and managing behaviors of FPSs. This study is the first to analyze the relationship between firefighting clothing and occupational health awareness level. The results confirm that future interventions are required to help firefighters practice desirable behaviors toward FPSs and provided evidenced data for preventing occupational diseases among firefighters. Therefore, this study can be used to develop a firefighter occupational health curriculum and establish health and safety plans from mid- to long-term perspectives for firefighters’ safety against occupational exposure risks. Full article

(This article belongs to the Section Fire Risk Assessment and Safety Management in Buildings and Urban Spaces)

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26 pages, 2281 KiB

Open AccessReview

A Comparative Review of Models for All-Solid-State Li-Ion Batteries

by Erkin Yildiz, Mattia Serpelloni, Alberto Salvadori and Luigi Cabras

Batteries 2024, 10(5), 150; https://doi.org/10.3390/batteries10050150 (registering DOI) - 29 Apr 2024

Abstract

In recent times, there has been significant enthusiasm for the development of all-solid-state Li-ion batteries. This interest stems from a dual focus on safety—addressing concerns related to toxic and flammable organic liquid electrolytes—and the pursuit of high energy density. While liquid electrolyte batteries [...] Read more.

In recent times, there has been significant enthusiasm for the development of all-solid-state Li-ion batteries. This interest stems from a dual focus on safety—addressing concerns related to toxic and flammable organic liquid electrolytes—and the pursuit of high energy density. While liquid electrolyte batteries currently constitute the vast majority of commercial cells, solid electrolyte batteries show great promise. In parallel with experimental research, computational models clarify several fundamental physics that take place throughout battery operations. Giving up on reviewing a broad screening of the existing literature, we set out to select here a few highly relevant models, emphasizing some fundamental conceptual advancements and offering an in-depth and critical insight into the current state of the art. The papers we selected aim at providing the reader with a tangible and quantitative understanding of how all-solid-state Li-ion batteries operate, including the different mechanisms at play and the mathematical tools required to model the pertinent physics and mechanics. Full article

(This article belongs to the Section Battery Modelling, Simulation, Management and Application)

14 pages, 897 KiB

Open AccessArticle

Less Is More: Higher-Skilled Sim Racers Allocate Significantly Less Attention to the Track Relative to the Display Features than Lower-Skilled Sim Racers

by John M. Joyce, Mark J. Campbell, Fazilat Hojaji and Adam J. Toth

Vision 2024, 8(2), 27; https://doi.org/10.3390/vision8020027 (registering DOI) - 29 Apr 2024

Abstract

Simulated (sim) racing is an emerging esport that has garnered much interest in recent years and has been a relatively under-researched field in terms of expertise and performance. When examining expertise, visual attention has been of particular interest to researchers, with eye tracking [...] Read more.

Simulated (sim) racing is an emerging esport that has garnered much interest in recent years and has been a relatively under-researched field in terms of expertise and performance. When examining expertise, visual attention has been of particular interest to researchers, with eye tracking technology commonly used to assess visual attention. In this study, we examined the overt visual attention allocation of high- and low-skilled sim racers during a time trial task using Tobii 3 glasses. In the study, 104 participants were tested on one occasion, with 88 included in the analysis after exclusions. Participants were allocated to either group according to their fastest lap times. Independent t-tests were carried out with sidak corrections to test our hypotheses. Our results indicate that when eye tracking metrics were normalised to the lap time and corner sector time, there was a difference in the relative length of overt attention allocation (fixation behaviour) as lower-skilled racers had significantly greater total fixation durations in laps overall and across corner sectors when normalised (p = 0.013; p = 0.018). Interestingly, high- and low-skilled sim racers differed in where they allocated their attention during the task, with high-skilled sim racers allocating significantly less overt attention to the track relative to other areas of the display (p = 0.003). This would allow for higher-skilled racers to obtain relatively more information from heads-up display elements in-game, all whilst driving at faster speeds. This study provides evidence that high-skilled sim racers appear to need significantly less overt attention throughout a fast lap, and that high- and low-skilled sim racers differ in where they allocate their attention while racing. Full article

17 pages, 1282 KiB

Open AccessArticle

Considering Grouped or Individual Non-Methane Volatile Organic Compound Emissions in Life Cycle Assessment of Composting Using Three Life Cycle Impact Assessment Methods

by Ben Joseph and Heinz Stichnothe

Recycling 2024, 9(3), 35; https://doi.org/10.3390/recycling9030035 (registering DOI) - 29 Apr 2024

Abstract

Composting is a waste management practice that converts organic waste into a product that can be used safely and beneficially as a bio-fertiliser and soil amendment. Non-methane volatile organic compounds (NMVOCs) from composting are known to cause damage to human health and the [...] Read more.

Composting is a waste management practice that converts organic waste into a product that can be used safely and beneficially as a bio-fertiliser and soil amendment. Non-methane volatile organic compounds (NMVOCs) from composting are known to cause damage to human health and the environment. The impact of waste management on the environment and workers is recognised as a growing environmental and public health concern. Measurements of NMVOCs emitted during composting have been carried out only in a few studies. NMVOC emissions are typically reported as a group rather than as species or speciation profiles. Recognising the need to investigate the issues associated with NMVOCs, the objective of this study is to estimate variation in life cycle assessment (LCA) results when NMVOCs are considered individual emissions compared to grouped emissions and to compare midpoint and endpoint life cycle impact assessment (LCIA) methods. In general, the ReCiPe 2016 LCIA method estimated the highest impact from the composting process in comparison to IMPACT World+ and EF 3.0 for the impact categories of ozone formation, stratospheric ozone depletion, and particulate matter formation. For ReCiPe 2016 and IMPACT World+, the NMVOC emissions were not linked to human toxicity characterisation factors, meaning that the contribution from NMVOC towards human health risks in and around composting facilities could be underestimated. Using individual NMVOCs helps to additionally estimate the impacts of composting on freshwater ecotoxicity and human carcinogenic and non-carcinogenic toxicity potential. If ecotoxicity or toxicity issues are indicated, then LCA should be accompanied by suitable risk assessment measures for the respective life cycle stage. Full article

(This article belongs to the Special Issue Feature Papers in Recycling 2023)

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17 pages, 3204 KiB

Open AccessArticle

Enhancing the Content of Hesperidin and Nobiletin in Citrus Wines through Multi-Strain Fermentation

by Shaoqing Zou, Yerui Ouyang, Linfeng Xie, Jiantao Liu, Ya Wang, Yiwen Xiao, Boliang Gao and Du Zhu

Fermentation 2024, 10(5), 238; https://doi.org/10.3390/fermentation10050238 (registering DOI) - 29 Apr 2024

Abstract

This research investigates how different fermentation techniques using non-Saccharomyces yeast (Candida ethanolica Ce, Hanseniaspora guilliermondii Hg, Hanseniaspora thailandica Ht) and Saccharomyces cerevisiae (Sc) affect the synthesis of hesperidin, nobiletin, and other flavonoid and aromatic substances, which play a vital [...] Read more.

This research investigates how different fermentation techniques using non-Saccharomyces yeast (Candida ethanolica Ce, Hanseniaspora guilliermondii Hg, Hanseniaspora thailandica Ht) and Saccharomyces cerevisiae (Sc) affect the synthesis of hesperidin, nobiletin, and other flavonoid and aromatic substances, which play a vital role in improving the overall quality of fruit wines due to their various biological properties. The combination of Sc:(Ce.Ht)-1:100 (Ce 0.5 × 10⁷ CFU/mL, Ht 0.5 × 10⁷ CFU/mL, Sc 1 × 10⁵ CFU/mL) yielded the highest hesperidin content at 4.12 ± 0.08 mg/L, followed by the Sc:(Ce.Hg)-1:1 (Ce 0.5 × 10⁷ CFU/mL, Hg 0.5 × 10⁷ CFU/mL, Sc 1 × 10⁷ CFU/mL) combination at 4.08 ± 0.06 mg/L. The highest nobiletin content was achieved by the (Hg.Ht)-10-Sc (Hg 0.5 × 10⁷ CFU/mL, Ht 0.5 × 10⁷ CFU/mL, Sc 1 × 10⁷ CFU/mL) combination, reaching 1.04 ± 0.05 mg/L, which was significantly higher than other multi-strain combinations. Additionally, the hesperidin content produced by the (Hg.Ht)-10-Sc combination was relatively high at 4.04 ± 0.02 mg/L, demonstrating a richness and complexity of aroma superior to that of fermentation with commercial yeast strains alone. The findings suggest that the (Hg.Ht)-10-Sc combination is the most effective multi-strain combination for increasing the levels of nobiletin and hesperidin in citrus wine, thereby enhancing the overall quality of the wine. These experimental results offer a promising approach for enhancing the quality of citrus wines and other fruit wines. Full article

(This article belongs to the Section Fermentation for Food and Beverages)

18 pages, 2899 KiB

Open AccessReview

Green and Low-Cost Modified Pisha Sandstone Geopolymer Gel Materials for Ecological Restoration: A Phase Review

by Changming Li, Yubing Fu, Haifeng Cheng, Yaozong Wang, Dongyang Jia and Hui Liu

Gels 2024, 10(5), 302; https://doi.org/10.3390/gels10050302 (registering DOI) - 29 Apr 2024

Abstract

Pisha sandstone (PS) is a special interbedded rock in the middle reaches of the Yellow River that experiences severe weathering and is loose and broken. Due to severe multiple erosion events, the Pisha sandstone region is called “the most severe water loss and [...] Read more.

Pisha sandstone (PS) is a special interbedded rock in the middle reaches of the Yellow River that experiences severe weathering and is loose and broken. Due to severe multiple erosion events, the Pisha sandstone region is called “the most severe water loss and soil erosion in the world” and “the ecological cancer of the earth”. As a special pozzolanic mineral, PS has the potential to be used as precursors for the synthesis of green and low-carbon geopolymer gel materials and applied in ecological restoration. This paper aims to undertake a phase review of the precursors for geopolymer gel materials. The genesis and distribution, physical and chemical characterization, erosion characteristics, and advances in the ecological restoration of PS are all summarized. Furthermore, current advances in the use of PS for the synthesis of geopolymer gel materials in terms of mechanical properties and durability are discussed. The production of Pisha sandstone geopolymer gels through the binder jetting technique and 3D printing techniques is prospected. Meanwhile, the prospects for the resource application of PS in mine rehabilitation and sustainable ecology are discussed. In the future, multifactor-driven comprehensive measures should be further investigated in order to achieve ecological restoration of the Pisha sandstone region and promote high-quality development of the Yellow River Basin. Full article

(This article belongs to the Special Issue Gels: Synthesis, Characterization and Applications in High Performance Chemistry (2nd Edition))

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15 pages, 3379 KiB

Open AccessArticle

Transcriptional Analysis Revealing the Improvement of ε-Poly-L-lysine Production from Intracellular ROS Elevation after Botrytis cinerea Induction

by Chen Zhang, Zhanyang Zhang, Ya Cheng, Ni Ni, Siyu Tong, Wangbao Da, Chunyan Liu, Qiran Diao, Ziyan Chen, Bingyue Xin, Huawei Zeng, Xin Zeng and Dayong Xu

J. Fungi 2024, 10(5), 324; https://doi.org/10.3390/jof10050324 (registering DOI) - 29 Apr 2024

Abstract

Gray mold, caused by Botrytis cinerea, poses significant threats to various crops, while it can be remarkably inhibited by ε-poly-L-lysine (ε-PL). A previous study found that B. cinerea extracts could stimulate the ε-PL biosynthesis of Streptomyces albulus, while it is unclear [...] Read more.

Gray mold, caused by Botrytis cinerea, poses significant threats to various crops, while it can be remarkably inhibited by ε-poly-L-lysine (ε-PL). A previous study found that B. cinerea extracts could stimulate the ε-PL biosynthesis of Streptomyces albulus, while it is unclear whether the impact of the B. cinerea signal on ε-PL biosynthesis is direct or indirect. This study evaluated the role of elevated reactive oxygen species (ROS) in efficient ε-PL biosynthesis after B. cinerea induction, and its underlying mechanism was disclosed with a transcriptome analysis. The microbial call from B. cinerea could arouse ROS elevation in cells, which fall in a proper level that positively influenced the ε-PL biosynthesis. A systematic transcriptional analysis revealed that this proper dose of intracellular ROS could induce a global transcriptional promotion on key pathways in ε-PL biosynthesis, including the embden-meyerhof-parnas pathway, the pentose phosphate pathway, the tricarboxylic acid cycle, the diaminopimelic acid pathway, ε-PL accumulation, cell respiration, and energy synthesis, in which sigma factor HrdD and the transcriptional regulators of TcrA, TetR, FurA, and MerR might be involved. In addition, the intracellular ROS elevation also resulted in a global modification of secondary metabolite biosynthesis, highlighting the secondary signaling role of intracellular ROS in ε-PL production. This work disclosed the transcriptional mechanism of efficient ε-PL production that resulted from an intracellular ROS elevation after B. cinerea elicitors’ induction, which was of great significance in industrial ε-PL production as well as the biocontrol of gray mold disease. Full article

(This article belongs to the Special Issue Biocontrol of Grapevine Diseases, 2nd Edition)

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13 pages, 2234 KiB

Open AccessArticle

Assessing Metal Exposure and Leaching from Discarded Cigarette Butts: Environmental Analysis and Integrated Waste Management Approaches

by Muhammad Faisal, Zai-Jin You, Noman Ali Buttar, Muhammad Bilal Idrees, Muhammad Naeem, Shoaib Ali, Basharat Ali, Abeer Hashem and Elsayed Fathi Abd_Allah

Toxics 2024, 12(5), 324; https://doi.org/10.3390/toxics12050324 (registering DOI) - 29 Apr 2024

Abstract

Cigarette butts, often discarded as litter, are considered a common form of waste, containing a variety of pollutants within this hazardous residue. This study, which was designed to assess the environmental release of certain metals from cigarette butts, investigates a variety of scenarios [...] Read more.

Cigarette butts, often discarded as litter, are considered a common form of waste, containing a variety of pollutants within this hazardous residue. This study, which was designed to assess the environmental release of certain metals from cigarette butts, investigates a variety of scenarios under varying climatic conditions. Thus, in order to assess the level of metal contamination, samples of cigarette butts were collected in urban areas from seven popular brands in China, smoked artificially, and examined through graphite furnace atomic absorption (GF-AAS). The findings indicated mean concentrations of 1.77 for Cr, 2.88 for Ni, 12.93 for Cu, 24.25 for Zn, and 1.77 µg/g for Pb in the case of newly smoked butts. The emission of each of the metals increases to 8–10% when cigarette butts remain in the environment for an extended period of time. Furthermore, rainfall can accelerate metal leaching, reaching values of 18–20% compared to the controlled scenario. The worst-case scenario releases 2129.31 kg/year of metals into the environment, while the best-case scenario sees a lower release of 844.97 kg/year. The data reflect variations in metal emissions across different scenarios. There was also a strong correlation between cigarette butts in public spaces and cities. This research highlights the need to educate smokers and increase urban maintenance efficiency to reduce this litter and the metals it leaches into the environment. Full article

(This article belongs to the Special Issue Characterization and Risk Assessment of Heavy Metals in Dust)

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17 pages, 1090 KiB

Open AccessArticle

Ride-Hailing Matching with Uncertain Travel Time: A Novel Interval-Valued Fuzzy Multi-Objective Linear Programming Approach

by Sudradjat Supian, Subiyanto, Tubagus Robbi Megantara and Abdul Talib Bon

Mathematics 2024, 12(9), 1355; https://doi.org/10.3390/math12091355 (registering DOI) - 29 Apr 2024

Abstract

This study introduces an innovative approach to tackle multi-objective linear programming (MOLP) problems amidst uncertainty, employing interval-valued fuzzy numbers. The method is tailored to resolve ride-hailing matching challenges encompassing uncertain travel times. Findings reveal that managing uncertainty parameters within interval-valued fuzzy MOLP is [...] Read more.

This study introduces an innovative approach to tackle multi-objective linear programming (MOLP) problems amidst uncertainty, employing interval-valued fuzzy numbers. The method is tailored to resolve ride-hailing matching challenges encompassing uncertain travel times. Findings reveal that managing uncertainty parameters within interval-valued fuzzy MOLP is achieved through strategic reformulations, focusing on constraint coefficients, resulting in streamlined linear programming formulations conducive to solution simplicity. The efficacy of the proposed model in efficiently handling ride-hailing matching quandaries is demonstrated. Moreover, this study delves into the prospective applications of the developed method, including its potential for generalization to address non-linear programming (NLP) issues pertinent to the ride-hailing domain. This research advances decision-making processes under uncertainty and paves the way for broader applications beyond ride-hailing. Full article

(This article belongs to the Section Fuzzy Sets, Systems and Decision Making)

20 pages, 2332 KiB

Open AccessArticle

Dynamic Behavior and Bifurcation Analysis of a Modified Reduced Lorenz Model

by Mohammed O. Al-Kaff, Ghada AlNemer, Hamdy A. El-Metwally, Abd-Elalim A. Elsadany and Elmetwally M. Elabbasy

Mathematics 2024, 12(9), 1354; https://doi.org/10.3390/math12091354 (registering DOI) - 29 Apr 2024

Abstract

This study introduces a newly modified Lorenz model capable of demonstrating bifurcation within a specified range of parameters. The model demonstrates various bifurcation behaviors, which are depicted as distinct structures in the diagram. The study aims to discover and analyze the existence and [...] Read more.

This study introduces a newly modified Lorenz model capable of demonstrating bifurcation within a specified range of parameters. The model demonstrates various bifurcation behaviors, which are depicted as distinct structures in the diagram. The study aims to discover and analyze the existence and stability of fixed points in the model. To achieve this, the center manifold theorem and bifurcation theory are employed to identify the requirements for pitchfork bifurcation, period-doubling bifurcation, and Neimark–Sacker bifurcation. In addition to theoretical findings, numerical simulations, including bifurcation diagrams, phase pictures, and maximum Lyapunov exponents, showcase the nuanced, complex, and diverse dynamics. Finally, the study applies the Ott–Grebogi–Yorke (OGY) method to control the chaos observed in the reduced modified Lorenz model. Full article

(This article belongs to the Special Issue Applied Mathematics in Nonlinear Dynamics and Chaos)

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17 pages, 1834 KiB

Open AccessArticle

Pollution Characteristics and Risk Assessment of Heavy Metals in the Sediments of the Inflow Rivers of Dianchi Lake, China

by Liwei He, Guangye Chen, Xinze Wang, Jian Shen, Hongjiao Zhang, Yuanyuan Lin, Yang Shen, Feiyan Lang and Chenglei Gong

Toxics 2024, 12(5), 322; https://doi.org/10.3390/toxics12050322 (registering DOI) - 29 Apr 2024

Abstract

To explore the contamination status and identify the source of the heavy metals in the sediments in the major inflow rivers of Dianchi Lake in China, sediment samples were collected and analyzed. Specifically, the distribution, source, water quality, and health risk assessment of [...] Read more.

To explore the contamination status and identify the source of the heavy metals in the sediments in the major inflow rivers of Dianchi Lake in China, sediment samples were collected and analyzed. Specifically, the distribution, source, water quality, and health risk assessment of the heavy metals were analyzed using correlation analysis (CA), principal component analysis (PCA), the heavy metal contamination factor (C_f), the pollution load index (PLI), and the potential ecological risk index (PERI). Additionally, the chemical fractions were analyzed for mobility characteristics. The results indicate that the average concentration of the heavy metals in the sediment ranked in the descending order of Zn > Cr > Cu > Pb > As > Ni > Cd > Hg, and most of the elements existed in less-mobile forms. The C_fwas in the order of Hg > Zn > Cd > As > Pb > Cr > Ni; the accumulation of Hg, Zn, Cd, and As was obvious. Although the spatial variability of the heavy metal contents was pronounced, the synthetical evaluation index of the PLI and PERI both reached a high pollution level. The PCA and CA results indicate that industrial, transportation, and agricultural emissions were the dominant factors causing heavy metal pollution. These results provide important data for improving water resource management efficiency and heavy metal pollution prevention in Dianchi Lake. Full article

(This article belongs to the Section Metals and Radioactive Substances)

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8 pages, 663 KiB

Open AccessArticle

Practical Security of Continuous Variable Quantum Key Distribution Ascribable to Imperfect Modulator for Fiber Channel

by Shengzhe Xu, Zicheng Zhou and Ying Guo

Mathematics 2024, 12(9), 1356; https://doi.org/10.3390/math12091356 (registering DOI) - 29 Apr 2024

Abstract

An amplitude modulator plays an essential role in the implementation of continuous-variable quantum key distribution (CVQKD), whereas it may bring about a potential security loophole in the practical system. The high-frequency modulation of the actual transmitter usually results in the high rate of [...] Read more.

An amplitude modulator plays an essential role in the implementation of continuous-variable quantum key distribution (CVQKD), whereas it may bring about a potential security loophole in the practical system. The high-frequency modulation of the actual transmitter usually results in the high rate of the system. However, an imperfect amplitude modulator (AM) can give birth to a potential information leakage from the modulation of the transmitter. To reveal a potential security loophole from the high-frequency AM embedded in the transmitter, we demonstrate an influence on the practical security of the system in terms of the secret key rate and maximal transmission distance. The results indicate the risk of this security loophole in the imperfect AM-embedded transmitter. Fortunately, the legal participants can trace back the potential information leakage that has been produced from the imperfect transmitter at high frequencies, which can be used for defeating the leakage attack in CVQKD. We find the limitations of the imperfect AM-embedded transmitter of the high-frequency quantum system, and hence, we have to trade off the practical security and the modulation frequency of the AM-embedded transmitter while considering its implementation in a practical environment. Full article

(This article belongs to the Special Issue Quantum Cryptography and Encryption)

18 pages, 3588 KiB

Open AccessArticle

Risks to Human Health from Mercury in Gold Mining in the Coastal Region of Ecuador

by Carlos Mestanza-Ramón, Samantha Jiménez-Oyola, Juan Cedeño-Laje, Karla Villamar Marazita, Alex Vinicio Gavilanes Montoya, Danny Daniel Castillo Vizuete, Demmy Mora-Silva, Luis Santiago Carrera Almendáriz, Santiago Logroño-Naranjo, Guido Mazón-Fierro, Renato Herrera-Chávez, Giovanni D’Orio and Salvatore Straface

Toxics 2024, 12(5), 323; https://doi.org/10.3390/toxics12050323 (registering DOI) - 29 Apr 2024

Abstract

Artisanal and small-scale gold mining (ASGM) plays a crucial role in global gold production. However, the adoption of poor mining practices or the use of mercury (Hg) in gold recovery processes has generated serious environmental contamination events. The focus of this study is [...] Read more.

Artisanal and small-scale gold mining (ASGM) plays a crucial role in global gold production. However, the adoption of poor mining practices or the use of mercury (Hg) in gold recovery processes has generated serious environmental contamination events. The focus of this study is assessing the concentration of Hg in surface waters within the coastal region of Ecuador. The results are used to conduct a human health risk assessment applying deterministic and probabilistic methods, specifically targeting groups vulnerable to exposure in affected mining environments. Between April and June 2022, 54 water samples were collected from rivers and streams adjacent to mining areas to determine Hg levels. In the health risk assessment, exposure routes through water ingestion and dermal contact were considered for both adults and children, following the model structures outlined by the U.S. Environmental Protection Agency. The results indicate elevated Hg concentrations in two of the five provinces studied, El Oro and Esmeraldas, where at least 88% and 75% of the samples, respectively, exceeded the maximum permissible limit (MPL) set by Ecuadorian regulations for the preservation of aquatic life. Furthermore, in El Oro province, 28% of the samples exceeded the MPL established for drinking water quality. The high concentrations of Hg could be related to illegal mining activity that uses Hg for gold recovery. Regarding the human health risk assessment, risk values above the safe exposure limit were estimated. Children were identified as the most vulnerable receptor. Therefore, there is an urgent need to establish effective regulations that guarantee the protection of river users in potentially contaminated areas. Finally, it is important to continue investigating the contamination caused by human practices in the coastal region. Full article

(This article belongs to the Special Issue Environmental Exposure to Toxic Chemicals and Human Health II)

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21 pages, 1985 KiB

Open AccessArticle

Improvements in Probabilistic Strategies and Their Application to Turbomachinery

by Andriy Prots, Matthias Voigt and Ronald Mailach

Aerospace 2024, 11(5), 355; https://doi.org/10.3390/aerospace11050355 (registering DOI) - 29 Apr 2024

Abstract

This paper discusses various strategies for probabilistic analysis, with a focus on typical engineering applications. The emphasis is on sampling methods and sensitivity analysis. A new sampling method, Latinized particle sampling, is introduced and compared to existing sampling methods. While it can increase [...] Read more.

This paper discusses various strategies for probabilistic analysis, with a focus on typical engineering applications. The emphasis is on sampling methods and sensitivity analysis. A new sampling method, Latinized particle sampling, is introduced and compared to existing sampling methods. While it can increase the quality of surrogate models, an optimized Latin hypercube sampling is mostly preferable as it shows slightly better results. In sensitivity analysis, the difficulty lies in correlated input variables, which are typical in engineering applications. First, the Sobol indices and the Shapley values are explained using an intuitive example. Then, the modified coefficient of importance is introduced as a new sensitivity measure, which can be used to reliably identify input variables without functional influence. Finally, these results are applied to a turbomachinery test case. In this case, the flow field of a compressor row is investigated, where the blades are subjected to geometric variability. The profile parameters used to describe the geometric variability are correlated. It is shown that the variability of the maximum camber and the thickness of the leading edge have a decisive influence on the variability of the isentropic efficiency. Full article

(This article belongs to the Special Issue Data-Driven Aerodynamic Modeling)

21 pages, 5082 KiB

Open AccessArticle

Analysis of the Synchronized Locking Dynamic Characteristics of a Dual-Sidestay Main Landing Gear Retraction Mechanism

by Zhipeng Zhang, Shengxiao Wu, He Zhu, Hong Nie and Xiaohui Wei

Aerospace 2024, 11(5), 356; https://doi.org/10.3390/aerospace11050356 (registering DOI) - 29 Apr 2024

Abstract

As an advanced design technology for large wide-body airliners, the three-dimensional (3D) dual-sidestay (DSS) landing gear retraction mechanism can share the ground loads transferred by the landing gear, reducing the load on the wings. However, the addition of a strut system may significantly [...] Read more.

As an advanced design technology for large wide-body airliners, the three-dimensional (3D) dual-sidestay (DSS) landing gear retraction mechanism can share the ground loads transferred by the landing gear, reducing the load on the wings. However, the addition of a strut system may significantly impact the synchronous locking performance of the landing gear with extremely high sensitivity. To study this impact pattern, both a rigid–flexible-coupling dynamic model of DSS landing gear considering joint clearance and node deviation and a synchronous locking test platform are established in this paper, and the simulation model is validated through the experimental results. Based on the simulation model, this paper conducts a detailed study on the influence of different node deviations and joint clearance on the synchronous locking dynamic characteristics of the DSS landing gear. The results show that, as the node deviation increases, the locking of the lock link gradually lags until one side cannot be fully locked; the structural clearance has a smaller impact on the synchronous locking of the landing gear. The feasible region of parameters satisfying the synchronous locking condition is given, which provides a basis and support for the parameter design of dual-sidestay retraction mechanisms. Full article

(This article belongs to the Section Aeronautics)

18 pages, 6724 KiB

Open AccessArticle

CFD Simulations and Phenomenological Modelling of Aerodynamic Stall Hysteresis of NACA 0018 Wing

by Mohamed Sereez, Nikolay Abramov and Mikhail Goman

Aerospace 2024, 11(5), 354; https://doi.org/10.3390/aerospace11050354 (registering DOI) - 29 Apr 2024

Abstract

Computational simulations of three-dimensional flow around a NACA 0018 wing with an aspect ratio of

A R = 5

were carried out by using the Unsteady Reynolds-Averaged Navier–Stokes (URANS) equations with the Shear-Stress Transport turbulence model closure. Simulations were performed to capture aerodynamic [...] Read more.

Computational simulations of three-dimensional flow around a NACA 0018 wing with an aspect ratio of

A R = 5

were carried out by using the Unsteady Reynolds-Averaged Navier–Stokes (URANS) equations with the Shear-Stress Transport turbulence model closure. Simulations were performed to capture aerodynamic stall hysteresis by using the developed pseudo-transient continuation (PTC) method based on a dual-time step approach in CFD OpenFOAM code. The flow was characterized by incompressible Mach number

M = 0.12

and moderate Reynolds number

R e = 0.67 \times 10^{6}

. The results obtained indicate the presence of noticeable aerodynamic hysteresis in the static dependencies of the force and moment coefficients, as well as the manifestation of bi-stable flow separation patterns, accompanied by the development of asymmetry in the stall zone. The URANS simulation results are in good agreement with the experimental data obtained for the NACA 0018 finite-aspect-ratio wing in the low-speed wind tunnel under the same test conditions. A new phenomenological bifurcation model of aerodynamic stall hysteresis under static and dynamic conditions is formulated and is proven to be able to closely match the experimental data. Full article

(This article belongs to the Special Issue Recent Advances in Applied Aerodynamics)

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19 pages, 3458 KiB

Open AccessArticle

Overexpression of MsDREB1C Modulates Growth and Improves Forage Quality in Tetraploid Alfalfa (Medicago sativa L.)

by Yangyang Zhang, Zhen Wang, Fan Zhang, Xue Wang, Yajing Li, Ruicai Long, Mingna Li, Xianyang Li, Quanzhen Wang, Qingchuan Yang and Junmei Kang

Plants 2024, 13(9), 1237; https://doi.org/10.3390/plants13091237 (registering DOI) - 29 Apr 2024

Abstract

DREB has been reported to be involved in plant growth and response to environmental factors. However, the function of DREB in growth and development has not been elucidated in alfalfa (Medicago sativa L.), a perennial tetraploid forage cultivated worldwide. In this study, [...] Read more.

DREB has been reported to be involved in plant growth and response to environmental factors. However, the function of DREB in growth and development has not been elucidated in alfalfa (Medicago sativa L.), a perennial tetraploid forage cultivated worldwide. In this study, an ortholog of MtDREB1C was characterized from alfalfa and named MsDREB1C accordingly. MsDREB1C was significantly induced by abiotic stress. The transcription factor MsDREB1C resided in the nucleus and had self-transactivation activity. The MsDREB1C overexpression (OE) alfalfa displayed growth retardation under both long-day and short-day conditions, which was supported by decreased MsGA20ox and upregulated MsGA2ox in the OE lines. Consistently, a decrease in active gibberellin (GA) was detected, suggesting a negative effect of MsDREB1C on GA accumulation in alfalfa. Interestingly, the forage quality of the OE lines was better than that of WT lines, with higher crude protein and lower lignin content, which was supported by an increase in the leaf–stem ratio (LSR) and repression of several lignin-synthesis genes (MsNST, MsPAL1, MsC4H, and Ms4CL). Therefore, this study revealed the effects of MsDREB1C overexpression on growth and forage quality via modifying GA accumulation and lignin synthesis, respectively. Our findings provide a valuable candidate for improving the critical agronomic traits of alfalfa, such as overwintering and feeding value of the forage. Full article

(This article belongs to the Section Plant Development and Morphogenesis)

22 pages, 6079 KiB

Open AccessArticle

Numerical Simulation of Water Film Flow and Breakup on Anti-Icing Surface

by Changxian Zhang, Lei Liu, Yaping Hu and Pengfei Li

Aerospace 2024, 11(5), 352; https://doi.org/10.3390/aerospace11050352 (registering DOI) - 29 Apr 2024

Abstract

The flow and morphological characteristics of liquid water on the icing and anti-icing surfaces of aircraft are closely related to the icing characteristics and anti-icing surface temperature distribution. To predict the flow and breakup characteristics of a water film, a 3D model of [...] Read more.

The flow and morphological characteristics of liquid water on the icing and anti-icing surfaces of aircraft are closely related to the icing characteristics and anti-icing surface temperature distribution. To predict the flow and breakup characteristics of a water film, a 3D model of continuous water film flow and a model of water film breakup into rivulets on an anti-icing surface were constructed based on the icing model, and the corresponding methods for solving the models were developed. Using the NACA0012 airfoil as a simulation object, the changing characteristics of height and velocity for a continuous water film with time and the morphological characteristics of rivulets formed from the breakup of a continuous water film were simulated numerically. The results indicate that, with an increase in inflow velocity, the time required for the water film to completely cover the surface and reach stability decreases. Downstream in the water droplet impact zone, the calculated values of continuous water film height align well with experiments, as well as the stream height at the continuous water film rupture location with the experimental values. With the reasonable contact angle, the calculation error of the stream width is within 10%. Full article

(This article belongs to the Special Issue Deicing and Anti-Icing of Aircraft (Volume III))

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16 pages, 2702 KiB

Open AccessArticle

Experimental Validation of a Passive-Adaptive Slat Concept and Characterization under Sinusoidal Fluctuations in the Angle of Attack

by Piyush Singh, Florian Schmidt, Jochen Wild, Johannes Riemenschneider, Joachim Peinke and Michael Hölling

Aerospace 2024, 11(5), 353; https://doi.org/10.3390/aerospace11050353 (registering DOI) - 29 Apr 2024

Abstract

This article presents an experimental investigation of a passive-adaptive slat concept, an aerodynamic control mechanism aimed at avoiding separation in the inwards region of a horizontal axis wind turbine blade. The passive-adaptive slat is designed to autonomously adjust its position due to the [...] Read more.

This article presents an experimental investigation of a passive-adaptive slat concept, an aerodynamic control mechanism aimed at avoiding separation in the inwards region of a horizontal axis wind turbine blade. The passive-adaptive slat is designed to autonomously adjust its position due to the aerodynamic forces acting on it, without the need of any active control system or external power source. The slat opens when the angle of attack increases beyond a certain threshold so that stall is delayed and closes for smaller angles of attack to increase the lift-to-drag ratio of the airfoil. A thorough aerodynamic characterisation of the passive-adaptive slat is performed in the wind tunnel followed by testing it under different sinusoidal inflows generated by a 2D active grid. It is observed that the slat system is able to leverage the advantages of both a clean airfoil and an airfoil with a fixed slat. It has the capability of delaying stalls for higher angles of attack, as well as having higher lift-to-drag ratio for lower angles of attack. It is also observed that, for fluctuating inflow, the passive-adaptive slat is able to achieve similar mean lift values as an airfoil with fixed slat while showing significant reduction in the lift fluctuations. Full article

(This article belongs to the Special Issue Gust Influences on Aerospace)

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29 pages, 3554 KiB

Open AccessReview

Echinacea: Bioactive Compounds and Agronomy

by Fatemeh Ahmadi, Khalil Kariman, Milad Mousavi and Zed Rengel

Plants 2024, 13(9), 1235; https://doi.org/10.3390/plants13091235 (registering DOI) - 29 Apr 2024

Abstract

For centuries, medicinal plants have been used as sources of remedies and treatments for various disorders and diseases. Recently, there has been renewed interest in these plants due to their potential pharmaceutical properties, offering natural alternatives to synthetic drugs. Echinacea, among the world’s [...] Read more.

For centuries, medicinal plants have been used as sources of remedies and treatments for various disorders and diseases. Recently, there has been renewed interest in these plants due to their potential pharmaceutical properties, offering natural alternatives to synthetic drugs. Echinacea, among the world’s most important medicinal plants, possesses immunological, antibacterial, antifungal, and antiviral properties. Nevertheless, there is a notable lack of thorough information regarding the echinacea species, underscoring the vital need for a comprehensive review paper to consolidate existing knowledge. The current review provides a thorough analysis of the existing knowledge on recent advances in understanding the physiology, secondary metabolites, agronomy, and ecology of echinacea plants, focusing on E. purpurea, E. angustifolia, and E. pallida. Pharmacologically advantageous effects of echinacea species on human health, particularly distinguished for its ability to safeguard the nervous system and combat cancer, are discussed. We also highlight challenges in echinacea research and provide insights into diverse approaches to boost the biosynthesis of secondary metabolites of interest in echinacea plants and optimize their large-scale farming. Various academic databases were employed to carry out an extensive literature review of publications from 2001 to 2024. The medicinal properties of echinacea plants are attributed to diverse classes of compounds, including caffeic acid derivatives (CADs), chicoric acid, echinacoside, chlorogenic acid, cynarine, phenolic and flavonoid compounds, polysaccharides, and alkylamides. Numerous critical issues have emerged, including the identification of active metabolites with limited bioavailability, the elucidation of specific molecular signaling pathways or targets linked to echinacoside effects, and the scarcity of robust clinical trials. This raises the overarching question of whether scientific inquiry can effectively contribute to harnessing the potential of natural compounds. A systematic review and analysis are essential to furnish insights and lay the groundwork for future research endeavors focused on the echinacea natural products. Full article

(This article belongs to the Section Phytochemistry)

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17 pages, 836 KiB

Open AccessArticle

Explainable Artificial Intelligence Approach for Diagnosing Faults in an Induction Furnace

by Sajad Moosavi, Roozbeh Razavi-Far, Vasile Palade and Mehrdad Saif

Electronics 2024, 13(9), 1721; https://doi.org/10.3390/electronics13091721 (registering DOI) - 29 Apr 2024

Abstract

For over a century, induction furnaces have been used in the core of foundries for metal melting and heating. They provide high melting/heating rates with optimal efficiency. The occurrence of faults not only imposes safety risks but also reduces productivity due to unscheduled [...] Read more.

For over a century, induction furnaces have been used in the core of foundries for metal melting and heating. They provide high melting/heating rates with optimal efficiency. The occurrence of faults not only imposes safety risks but also reduces productivity due to unscheduled shutdowns. The problem of diagnosing faults in induction furnaces has not yet been studied, and this work is the first to propose a data-driven framework for diagnosing faults in this application. This paper presents a deep neural network framework for diagnosing electrical faults by measuring real-time electrical parameters at the supply side. Experimental and sensory measurements are collected from multiple energy analyzer devices installed in the foundry. Next, a semi-supervised learning approach, known as the local outlier factor, has been used to discriminate normal and faulty samples from each other and label the data samples. Then, a deep neural network is trained with the collected labeled samples. The performance of the developed model is compared with several state-of-the-art techniques in terms of various performance metrics. The results demonstrate the superior performance of the selected deep neural network model over other classifiers, with an average F-measure of 0.9187. Due to the black box nature of the constructed neural network, the model predictions are interpreted by Shapley additive explanations and local interpretable model-agnostic explanations. The interpretability analysis reveals that classified faults are closely linked to variations in odd voltage/current harmonics of order 3, 11, 13, and 17, highlighting the critical impact of these parameters on the model’s prediction. Full article

(This article belongs to the Special Issue Explainability in AI and Machine Learning)

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10 pages, 1059 KiB

Open AccessArticle

Variation in X_CO Factor in N55 Region

by Qiang Li, Mingyue Li, Li Zhang and Songpeng Pei

Universe 2024, 10(5), 200; https://doi.org/10.3390/universe10050200 (registering DOI) - 29 Apr 2024

Abstract

The

X_{C O}

factor is defined as

X_{C O} = N (H_{2}) / W_{12 C O}

. It is useful for estimating cloud mass. However, there is only limited research on how the

X_{C O}

factor [...] Read more.

The

X_{C O}

factor is defined as

X_{C O} = N (H_{2}) / W_{12 C O}

. It is useful for estimating cloud mass. However, there is only limited research on how the

X_{C O}

factor varies within a single cloud. Employing

^{12} C O (J = 1 - 0)

and

^{13} C O (J = 1 - 0)

spectral data, we computed an

X_{C O}

factor of 3.6

\times 10^{20} {cm}^{- 2}

(K km s

^{- 1})^{- 1}

for luminous gas of the N55 region. Our analysis revealed a V-shaped correlation between the

X_{C O}

factor and

H_{2}

column densities, while the relationship with excitation temperature exhibited obscurity. This suggests that the CO-to-

H_{2}

conversion is not consistent on small scale (∼1 pc). Additionally, we found that star formation activity has little influence on the variability in the

X_{C O}

factor. Full article

(This article belongs to the Section Stellar Astronomy)

19 pages, 1895 KiB

Open AccessArticle

Detection and Classification of Rolling Bearing Defects Using Direct Signal Processing with Deep Convolutional Neural Network

by Maciej Skowron, Oliwia Frankiewicz, Jeremi Jan Jarosz, Marcin Wolkiewicz, Mateusz Dybkowski, Sebastien Weisse, Jerome Valire, Agnieszka Wyłomańska, Radosław Zimroz and Krzysztof Szabat

Electronics 2024, 13(9), 1722; https://doi.org/10.3390/electronics13091722 (registering DOI) - 29 Apr 2024

Abstract

Currently, great emphasis is being placed on the electrification of means of transportation, including aviation. The use of electric motors reduces operating and maintenance costs. Electric motors are subjected to various types of damage during operation, of which rolling bearing defects are statistically [...] Read more.

Currently, great emphasis is being placed on the electrification of means of transportation, including aviation. The use of electric motors reduces operating and maintenance costs. Electric motors are subjected to various types of damage during operation, of which rolling bearing defects are statistically the most common. This article focuses on presenting a diagnostic tool for bearing conditions based on mechanic vibration signals using convolutional neural networks (CNN). This article presents an alternative to the well-known classical diagnostic tools based on advanced signal processing methods such as the short-time Fourier transform, the Hilbert–Huang transform, etc. The approach described in the article provides fault detection and classification in less than 0.03 s. The proposed structures achieved a classification accuracy of 99.8% on the test set. Special attention was paid to the process of optimizing the CNN structure to achieve the highest possible accuracy with the fewest number of network parameters. Full article

(This article belongs to the Special Issue Applications of Machine Learning and Artificial Intelligence in Modern Power and Energy Systems)

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