[go: up one dir, main page]
More Web Proxy on the site http://driver.im/
You seem to have javascript disabled. Please note that many of the page functionalities won't work as expected without javascript enabled.
 
 
Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Article Types

Countries / Regions

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Search Results (14,543)

Search Parameters:
Keywords = physical condition

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
18 pages, 1149 KiB  
Article
Postharvest Evaluations of Blackcurrant Fruits with Chitosan and Ultraviolet A Treatments
by Zhuoyu Wang, Andrej Svyantek, Zachariah Miller, Aude A. Watrelot and Venkateswara Rao Kadium
Appl. Sci. 2024, 14(24), 12052; https://doi.org/10.3390/app142412052 (registering DOI) - 23 Dec 2024
Abstract
The blackcurrant (Ribes nigrum L.) is a small fruit known for its health benefits, but treatment effects on postharvest storage for fresh markets remain understudied compared with other berries, such as blueberries (Vaccinium spp.). This work aimed to identify the effects [...] Read more.
The blackcurrant (Ribes nigrum L.) is a small fruit known for its health benefits, but treatment effects on postharvest storage for fresh markets remain understudied compared with other berries, such as blueberries (Vaccinium spp.). This work aimed to identify the effects of postharvest storage conditions including chitosan coating, ultraviolet a (UVA) light, and combined UVA–chitosan treatments on the physicochemical and microbial properties of blackcurrant. Blackcurrants were harvested, stored under the three conditions, and analyzed at every three days of storage throughout this experiment for a total of 15 days. The results indicated that chitosan treatments had positive effects on reducing berry weight loss, maintaining berry firmness, and reducing mold populations. UVA influenced certain bioactive compounds, such as cyanidin-3-galactoside and rutin. The interaction effects from these two treatments were minimal. This study provides important information for blackcurrant postharvest storage and further small fruit storage work, considering both UVA and chitosan had differential beneficial effects on blackcurrant berries’ physical and chemical attributes. Full article
(This article belongs to the Section Food Science and Technology)
Show Figures

Figure 1

Figure 1
<p>Effects of postharvest treatments on weight loss. Each treatment contains three replicates. Bars indicate values are the mean ± standard deviations of replicates. Different letters correspond to mean values significantly different (<span class="html-italic">p</span> &lt; 0.05) by analysis of variance (ANOVA) and Tukey post hoc test across storage.</p>
Full article ">Figure 2
<p>Blackcurrant berry firmness changes during storage. Each treatment contains three replicates. Bars indicate values are the mean ± standard deviations of replicates. Different letters correspond to mean values significantly different (<span class="html-italic">p</span> &lt; 0.05) by analysis of variance (ANOVA) and Tukey post hoc test across storage.</p>
Full article ">Figure 3
<p>Microbial population measurements on blackcurrants during storage. Four treatments are included in the postharvest treatments. Different letters correspond to mean values significantly different (<span class="html-italic">p</span> &lt; 0.05) across storage by analysis of variance (ANOVA) and Tukey post hoc test. Each treatment at each storage days has three replicates.</p>
Full article ">
22 pages, 1959 KiB  
Article
Integration of Plant Pomace into Extruded Products: Analysis of Process Conditions, Post-Production Waste Properties and Biogas Potential
by Jakub Soja, Tomasz Oniszczuk, Iryna Vaskina, Maciej Combrzyński and Agnieszka Wójtowicz
Energies 2024, 17(24), 6476; https://doi.org/10.3390/en17246476 (registering DOI) - 23 Dec 2024
Abstract
Waste streams from cereal-based food production processes, rich in organic matter and carbohydrates, have untapped potential for biogas production. This study uniquely investigated the extrusion-cooking process conditions, physical properties and biogas efficiency of snack pellets enriched with plant pomace (apple, chokeberry, pumpkin, flaxseed [...] Read more.
Waste streams from cereal-based food production processes, rich in organic matter and carbohydrates, have untapped potential for biogas production. This study uniquely investigated the extrusion-cooking process conditions, physical properties and biogas efficiency of snack pellets enriched with plant pomace (apple, chokeberry, pumpkin, flaxseed and nigella seeds) at different levels (10, 20 and 30%), produced using a single-screw extruder-cooker. The highest efficiency obtained in the extrusion-cooking process (18.20 kg/h) was observed for pellets with the addition of 30% flaxseed pomace. The SME value during the entire process was in the range of 0.015–0.072 kWh/kg. New insights into the interaction between the inclusion of pomace, the physical properties of the extrudate and the anaerobic fermentation efficiency were obtained. The results show that 30% chokeberry extrudate maximized methane production (51.39% gas), demonstrating a double innovation: improving snack pellet quality and converting food waste into renewable energy. Full article
Show Figures

Figure 1

Figure 1
<p>Flowchart presenting the methodological framework of the study.</p>
Full article ">Figure 2
<p>Construction of a biofermentor for biogas production research: 1—water heater with temperature regulator, 2—water pump, 3—insulated conductors of calefaction liquid, 4—water coat, 5—fermenter with charge capacity 2 dm<sup>3</sup>, 6—sampling tubes, 7—biogas transporting tube, 8—gas sampling valve and 9—biogas volume-scale reservoir [<a href="#B29-energies-17-06476" class="html-bibr">29</a>].</p>
Full article ">Figure 3
<p>Methane content after anaerobic fermentation of post-production wastes of snack pellets with various types and amounts of additives; <sup>a–g</sup>—means indicated with similar letters in columns do not differ significantly at α = 0.05.</p>
Full article ">Figure 4
<p>Projection of variables as product parameters on the PC1 and PC2 loadings plot.</p>
Full article ">Figure 5
<p>Projection of sample type depending on pomace source on the PC1 and PC2 scores plot.</p>
Full article ">
13 pages, 915 KiB  
Article
Prevalence and Risk Factors of Osteoporosis: A Cross-Sectional Study in a Tertiary Center
by Samican Özmen, Sefa Kurt, Hikmet Tunç Timur, Onur Yavuz, Hakan Kula, Ayşegül Yılmaz Demir and Ali Balcı
Medicina 2024, 60(12), 2109; https://doi.org/10.3390/medicina60122109 (registering DOI) - 23 Dec 2024
Abstract
Background and Objectives: Osteoporosis is a common disease of the skeletal system that increases the risk of fracture. The prevalence of osteoporosis has been increasing as the aging population increases, affecting more than 200 million people worldwide. This study aimed to shed light [...] Read more.
Background and Objectives: Osteoporosis is a common disease of the skeletal system that increases the risk of fracture. The prevalence of osteoporosis has been increasing as the aging population increases, affecting more than 200 million people worldwide. This study aimed to shed light on the clinical impact of osteoporosis on women’s health and quality of life by evaluating the prevalence and risk factors for this disease among postmenopausal women, using a 10-year dataset from a tertiary center. Materials and Methods: This retrospective cohort study was conducted at Dokuz Eylül University, Department of Obstetrics and Gynecology, between 2010 and 2022. A total of 3289 postmenopausal women aged 50–60 years who were undergoing routine gynecological checkups were included in the study. Patients with a prior diagnosis, a history of medical conditions, or who were taking medications affecting bone mineral density (BMD) were excluded. Data on demographics, smoking status, diabetes status, body mass index (BMI), parity, and fracture history were collected. BMD scores were classified as normal, osteopenia, or osteoporosis. Results: The prevalence of osteoporosis was 10.4%. The median age of the patients was 56.0 years. Smoking, diabetes, and a history of bone fractures were found to significantly increase the risk of osteoporosis. BMI was found to have a protective effect against osteoporosis. According to multivariate analysis, the risk of osteoporosis increased by 2.46 times in patients who smoke, 3.78 times in patients with diabetes, and 6.23 times in patients with a history of fractures. Conclusions: Awareness of modifiable risk factors such as smoking is crucial for preventing osteoporosis-related complications. Diabetes, even when it is not complicated, increases the risk of osteoporosis. Physical exercise, calcium, and vitamin D intake are important, especially during young adulthood, as they are the primary contributors to peak bone mass. Because neck fractures are more common in patients with osteopenia, early diagnosis and routine screening can mitigate future complications. Full article
(This article belongs to the Section Obstetrics and Gynecology)
Show Figures

Figure 1

Figure 1
<p>Flowchart.</p>
Full article ">Figure 2
<p>Comparison of Diagnostic Groups.</p>
Full article ">Figure 3
<p>Comparison of diagnostic groups with risk factors. <sup>a</sup> chi-square test.</p>
Full article ">
14 pages, 1116 KiB  
Article
Cognitive Health Costs of Poor Housing for Women: Exploring Executive Function and Housing Stress in Urban Slums in India
by Uchita Vaid
Int. J. Environ. Res. Public Health 2024, 21(12), 1710; https://doi.org/10.3390/ijerph21121710 - 23 Dec 2024
Abstract
An increasing body of literature has investigated the implications of housing quality on health, confirming the negative consequences of poor housing quality on physical and mental health. Despite this increased focus on the salutogenic impacts of housing, the relationship between housing quality and [...] Read more.
An increasing body of literature has investigated the implications of housing quality on health, confirming the negative consequences of poor housing quality on physical and mental health. Despite this increased focus on the salutogenic impacts of housing, the relationship between housing quality and cognitive health remains understudied. This study examined how the housing quality in urban informal settlements, where living conditions are often substandard, affects women’s cognitive functioning, with a specific focus on executive function (EF) skills. EF is a decision-making system that enables us to make decisions using working memory and attentional control. This study addressed two key questions: (1) Is housing quality associated with EF skills? (2) Does perceived housing stress experienced by women mediate the housing–EF relationship? A standardized observer-based tool assessed housing quality, psychometric instruments measured EF skills, and a 12-item questionnaire evaluated perceived housing stress. Results indicated that better housing quality is positively associated with higher EF skills, with housing stress acting as a mediating factor in this relationship. These findings have important implications for both health and housing policies. Investments in improving housing conditions can yield cognitive health benefits for women, and addressing stress-inducing housing factors could further enhance cognitive outcomes. Full article
Show Figures

Figure 1

Figure 1
<p>(<b>a</b>) Congruent trialswith all arrows pointing right; (<b>b</b>) congruent trialswith all arrows pointing left; (<b>c</b>) incongruent trialswith central arrow pointing left and others pointing right; (<b>d</b>) incongruent trialswith central arrow pointing right and others pointing left.</p>
Full article ">Figure 2
<p>Housing stress as a mediator in explaining the relationship between housing problems and flanker reaction time.</p>
Full article ">Figure 3
<p>Housing stress as a mediator in explaining the relationship between housing problems and working memory.</p>
Full article ">
18 pages, 474 KiB  
Review
Craniocervical Posture and Malocclusion: A Comprehensive Literature Review of Interdisciplinary Insights and Implications
by Andreea Kui, Alexandru Bereanu, Ana-Maria Condor, Dalia Pop, Smaranda Buduru, Anca Labunet, Sebastian Șoicu, Rareș Buduru and Andrea Chisnoiu
Medicina 2024, 60(12), 2106; https://doi.org/10.3390/medicina60122106 (registering DOI) - 22 Dec 2024
Viewed by 292
Abstract
Background and Objectives: The impact of craniocervical posture on malocclusion has long intrigued researchers in dentistry, orthodontics, and physical therapy. This research aims to elucidate the relationship between craniocervical posture and both dental and skeletal malocclusions and to explore the potential for [...] Read more.
Background and Objectives: The impact of craniocervical posture on malocclusion has long intrigued researchers in dentistry, orthodontics, and physical therapy. This research aims to elucidate the relationship between craniocervical posture and both dental and skeletal malocclusions and to explore the potential for integrated multidisciplinary therapeutic approaches. Materials and Methods: We analyzed peer-reviewed articles published between 2013 and 2023 from PubMed/Medline, Web of Science, EMBASE, and Scopus. The search strategy included terms related to craniocervical posture and malocclusion, focusing on studies that evaluated the relationship between these conditions before and after various orthodontic or surgical treatments. Results: A total of 20 studies met the inclusion criteria, providing nuanced insights into the interplay between malocclusion types and craniocervical alignment. Findings suggest that altered craniocervical posture is more prevalent in individuals with skeletal malocclusions. In particular, orthodontic treatment and orthognathic surgery appear to influence craniocervical posture, suggesting a bidirectional relationship between craniofacial structure and neck alignment. Conclusions: Our literature review confirms a significant association between craniocervical posture and malocclusion, emphasizing the need for an integrative approach to the diagnosis and treatment of craniofacial anomalies. Future research should aim to quantify these relationships further through longitudinal studies, thereby increasing the understanding necessary to develop comprehensive treatment protocols. Full article
(This article belongs to the Special Issue Advancements in Dental Medicine, Oral Anesthesiology and Surgery)
20 pages, 4923 KiB  
Article
A Dual-Source Energy Balance Model Coupled with Jarvis Canopy Resistance for Estimating Surface Evapotranspiration in Arid and Semi-Arid Regions
by Qiutong Zhang, Jinling Kong, Lizheng Wang, Xixuan Wang, Zaiyong Zhang, Yizhu Jiang and Yanling Zhong
Agriculture 2024, 14(12), 2362; https://doi.org/10.3390/agriculture14122362 (registering DOI) - 22 Dec 2024
Viewed by 277
Abstract
Soil moisture is one of the main factors influencing evapotranspiration (ET) under soil water stress conditions. The TSEBSM model used soil moisture to constrain soil evaporation. However, the transpiration schemes constrained by soil moisture require greater physical realism and the soil evaporation [...] Read more.
Soil moisture is one of the main factors influencing evapotranspiration (ET) under soil water stress conditions. The TSEBSM model used soil moisture to constrain soil evaporation. However, the transpiration schemes constrained by soil moisture require greater physical realism and the soil evaporation schemes parameters usually need calibration. In this study, the TSEBSM model was enhanced by incorporating Jarvis’s canopy resistance which considered the influence of soil moisture on transpiration schemes. We assessed the new model (TSEBSM+) in the Heihe and Haihe basins of China. The TSEBSM+ model displayed a consistency to the TSEB in the ET estimation at the A’rou site, but approximately 30% and 35% reductions in RMSEs at the Huazhaizi and Huailai sites. It produced approximately 20% and 10% of the reductions in the ET RMSEs at the Huailai and A’rou sites compared to the TSEBSM model, but had a similar performance at the Huazhaizi site. Moreover, the TSEBSM+ model estimated ET in the Heihe River Basin with an RMSE of 0.58 mm·day−1, and it was sensitive to the soil moisture, particularly when the soil moisture was below 30%. In conjunction to soil moisture, the TSEBSM+ model could potentially be a more effective tool for monitoring the ET. Full article
(This article belongs to the Section Agricultural Soils)
Show Figures

Figure 1

Figure 1
<p>Maps of landcovers in Heihe and Haihe river basins and the locations of the EC flux towers ((<b>a</b>) the Huazhaizi site; (<b>b</b>) the A’rou site; (<b>c</b>) the Huailai site).</p>
Full article ">Figure 2
<p>Scatterplots of estimated half-hour R<sub>n</sub>, G, H and LE over the study period from the TSEB, TSEB<sub>SM</sub> and TSEB<sub>SM+</sub> models in comparison to the measurements from the EC system at the Huazhaizi site.</p>
Full article ">Figure 3
<p>Scatterplots of estimated half-hour R<sub>n</sub>, G, H and LE over the study period from the TSEB, TSEB<sub>SM</sub> and TSEB<sub>SM+</sub> models in comparison to the measurements from the EC system at the Huailai site.</p>
Full article ">Figure 4
<p>Scatterplots of estimated half-hour R<sub>n</sub>, G, H and LE over the study period from the TSEB, TSEB<sub>SM,</sub> and TSEB<sub>SM+</sub> models in comparison to the measurements from the EC system at the A’rou site.</p>
Full article ">Figure 5
<p>Comparison of daily ET between estimations via the TSEB, TSEB<sub>SM,</sub> and TSEB<sub>SM+</sub> models and observed from the EC system at the Huazhaizi site from DOY122-274 for 2020.</p>
Full article ">Figure 6
<p>Comparison of daily ET between estimations via the TSEB, TSEB<sub>SM,</sub> and TSEB<sub>SM+</sub> models and observed from the EC system at the Huailai site from DOY122-274 for 2020.</p>
Full article ">Figure 7
<p>Comparison of daily ET between estimations via the TSEB, TSEB<sub>SM,</sub> and TSEB<sub>SM+</sub> models and observed from the EC system at the A’rou site from DOY122-274 for 2020.</p>
Full article ">Figure 8
<p>The daily ET estimated via the TSEB<sub>SM+</sub> model for alpine meadows, croplands with corn, and desert steppes in the Heihe River Basin.</p>
Full article ">Figure 9
<p>Scatterplot of observed daily ET from the EC systems and daily ET modeled via the TSEB<sub>SM+</sub> model at seven sites.</p>
Full article ">Figure 10
<p>Scatterplots and tables of the comparison of the half-hour LE measured by the EC system and the estimation from the TSEB, TSEB<sub>SM</sub> and TSEB<sub>SM+</sub> models for the Huazhaizi, Huailai, and A’rou sites.</p>
Full article ">Figure 11
<p>Energy fluxes and evaporation ratios from the TSEB<sub>SM+</sub> model with a change in the soil moisture range from 12 to 45% for the Huazhaizi, Huailai and A’rou sites. The orange dotted line indicates that the LE growth rate estimated via the model decreases significantly when the soil moisture is exceeded.</p>
Full article ">
23 pages, 1502 KiB  
Article
Development of a New Generalizable, Multivariate, and Physical-Body-Response-Based Extreme Heatwave Index
by Marcio Cataldi, Vitor Luiz Victalino Galves, Leandro Alcoforado Sphaier, Ginés Garnés-Morales, Victoria Gallardo, Laurel Molina Párraga, Juan Pedro Montávez and Pedro Jimenez-Guerrero
Atmosphere 2024, 15(12), 1541; https://doi.org/10.3390/atmos15121541 - 22 Dec 2024
Viewed by 283
Abstract
The primary goal of this study is to introduce the initial phase of developing an impact-based forecasting system for extreme heatwaves, utilizing a novel multivariate index which, at this early stage, already employs a combination of a statistical approach and physical principles related [...] Read more.
The primary goal of this study is to introduce the initial phase of developing an impact-based forecasting system for extreme heatwaves, utilizing a novel multivariate index which, at this early stage, already employs a combination of a statistical approach and physical principles related to human body water loss. This system also incorporates a mitigation plan with hydration-focused measures. Since 1990, heatwaves have become increasingly frequent and intense across many regions worldwide, particularly in Europe and Asia. The main health impacts of heatwaves include organ strain and damage, exacerbation of cardiovascular and kidney diseases, and adverse reproductive effects. These consequences are most pronounced in individuals aged 65 and older. Many national meteorological services have established metrics to assess the frequency and severity of heatwaves within their borders. These metrics typically rely on specific threshold values or ranges of near-surface (2 m) air temperature, often derived from historical extreme temperature records. However, to our knowledge, only a few of these metrics consider the persistence of heatwave events, and even fewer account for relative humidity. In response, this study aims to develop a globally applicable normalized index that can be used across various temporal scales and regions. This index incorporates the potential health risks associated with relative humidity, accounts for the duration of extreme heatwave events, and is exponentially sensitive to exposure to extreme heat conditions above critical thresholds of temperature. This novel index could be more suitable/adapted to guide national meteorological services when emitting warnings during extreme heatwave events about the health risks on the population. The index was computed under two scenarios: first, in forecasting heatwave episodes over a specific temporal horizon using the WRF model; second, in evaluating the relationship between the index, mortality data, and maximum temperature anomalies during the 2003 summer heatwave in Spain. Moreover, the study assessed the annual trend of increasing extreme heatwaves in Spain using ERA5 data on a climatic scale. The results show that this index has considerable potential as a decision-support and health risk assessment tool. It demonstrates greater sensitivity to extreme risk episodes compared to linear evaluations of extreme temperatures. Furthermore, its formulation aligns with the physical mechanisms of water loss in the human body, while also factoring in the effects of relative humidity. Full article
(This article belongs to the Special Issue Prediction and Modeling of Extreme Weather Events)
14 pages, 1986 KiB  
Article
Shannon Entropy Analysis of a Nuclear Fuel Pin Under Deep Burnup
by Wojciech R. Kubiński, Jan K. Ostrowski and Krzysztof W. Fornalski
Entropy 2024, 26(12), 1124; https://doi.org/10.3390/e26121124 - 22 Dec 2024
Viewed by 134
Abstract
This paper analyzes the behavior of the entropy of a nuclear fuel rod under deep burnup conditions, beyond standard operational ranges, reaching up to 60 years. The evolution of the neutron source distribution in a pressurized water reactor (PWR) fuel pin was analyzed [...] Read more.
This paper analyzes the behavior of the entropy of a nuclear fuel rod under deep burnup conditions, beyond standard operational ranges, reaching up to 60 years. The evolution of the neutron source distribution in a pressurized water reactor (PWR) fuel pin was analyzed using the Monte Carlo method and Shannon information entropy. To maintain proper statistics, a novel scaling method was developed, adjusting the neutron population based on the fission rate. By integrating reactor physics with information theory, this work aimed at the deeper understanding of nuclear fuel behavior under extreme burnup conditions. The results show a “U-shaped” entropy evolution: an initial decrease due to self-organization, followed by stabilization and eventual increase due to degradation. A minimum entropy state is reached after approximately 45 years of pin operation, showing a steady-state condition with no entropy change. This point may indicate a physical limit for fuel utilization. Beyond this point, entropy rises, reflecting system degradation and lower energy efficiency. The results show that entropy analysis can provide valuable insights into fuel behavior and operational limits. The proposed scaling method may also serve to control a Monte Carlo simulation, especially for the analysis of long-life reactors. Full article
(This article belongs to the Special Issue Insight into Entropy)
12 pages, 364 KiB  
Article
Two-Point Resolution of a Defocused Imaging System Based on Spatially Coherent Illumination
by Gianlorenzo Massaro, Sergio de Gioia, Adalberto Brunetti, Francesco V. Pepe and Milena D’Angelo
Photonics 2024, 11(12), 1203; https://doi.org/10.3390/photonics11121203 - 22 Dec 2024
Viewed by 322
Abstract
We examine the physical limitations and performance of spatially coherent imaging systems under defocused conditions using a modified two-point resolution criterion. By comparing coherent and incoherent illumination regimes, in defocused conditions, we highlight the peculiar advantages of coherent systems in resolving closely spaced [...] Read more.
We examine the physical limitations and performance of spatially coherent imaging systems under defocused conditions using a modified two-point resolution criterion. By comparing coherent and incoherent illumination regimes, in defocused conditions, we highlight the peculiar advantages of coherent systems in resolving closely spaced features while maintaining a high depth of field. The analysis identifies two primary contributions to image degradation in coherent defocused systems: image broadening and interference-related contrast reduction. Through a specifically designed analytical framework, this study confirms that resolution degradation in coherent imaging is characterized by a square root dependence on defocusing distance, irrespective of the numerical aperture. This behavior starkly contrasts with incoherent imaging, where the resolution deteriorates linearly with defocusing and exhibits a strong dependence on the system’s numerical aperture. Furthermore, we provide explicit analytical expressions for contrast loss and minimum resolvable object size under defocused coherent conditions, offering deeper insights into their relation with system parameters. These results corroborate the superior performance of coherent imaging in resolving fine details in defocused environments, challenging conventional optical paradigms. Our findings not only extend the theoretical understanding of coherent imaging but also establish practical guidelines to optimize optical systems for high-resolution applications. Full article
Show Figures

Figure 1

Figure 1
<p>The left panel reports the theoretical intensity distribution in a coherent image and its composing parts [as identified in Equation (<a href="#FD7-photonics-11-01203" class="html-disp-formula">7</a>)], in the case of an object mask made of two Gaussian slits with width <math display="inline"><semantics> <mrow> <mi>σ</mi> <mo>=</mo> <mn>0.1</mn> </mrow> </semantics></math> mm and center-to-center separation <math display="inline"><semantics> <mrow> <mi>d</mi> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math> mm, placed at a defocusing distance <math display="inline"><semantics> <mrow> <mi>δ</mi> <mo>=</mo> <mn>170</mn> <mspace width="4pt"/> <mi>mm</mi> </mrow> </semantics></math>. The right panel shows the behavior of the intensity distribution in the same conditions but for increasing values of defocusing; broadening and interference are found to be more pronounced. Images in both plots are normalized to the intensity maximum of a single slit, and employed wavelength is 500 nm.</p>
Full article ">Figure 2
<p>The light blue area represents the region where the coherent images of the two Gaussian slits are resolvable in the sense of the contrast criterion for an arbitrarily chosen contrast threshold of 20. The boundary of this region is a curve representing the resolution limit of coherent imaging for the given threshold. The red curve represents the approximated resolution limit curve derived under the assumption of an infinite NA. The two curves almost perfectly overlap; the disagreement only occurs near the focus plane, where the NA sets Rayleigh’s limited resolution.</p>
Full article ">
33 pages, 9160 KiB  
Article
Optimized Analytical–Numerical Procedure for Ultrasonic Sludge Treatment for Agricultural Use
by Filippo Laganà, Salvatore A. Pullano, Giovanni Angiulli and Mario Versaci
Algorithms 2024, 17(12), 592; https://doi.org/10.3390/a17120592 (registering DOI) - 21 Dec 2024
Viewed by 457
Abstract
This paper presents an integrated approach based on physical–mathematical models and numerical simulations to optimize sludge treatment using ultrasound. The main objective is to improve the efficiency of the purification system by reducing the weight and moisture of the purification sludge, therefore ensuring [...] Read more.
This paper presents an integrated approach based on physical–mathematical models and numerical simulations to optimize sludge treatment using ultrasound. The main objective is to improve the efficiency of the purification system by reducing the weight and moisture of the purification sludge, therefore ensuring regulatory compliance and environmental sustainability. A coupled temperature–humidity model, formulated by partial differential equations, describes materials’ thermal and water evolution during treatment. The numerical resolution, implemented by the finite element method (FEM), allows the simulation of the system behavior and the optimization of the operating parameters. Experimental results confirm that ultrasonic treatment reduces the moisture content of sludge by up to 20% and improves its stability, making it suitable for agricultural applications or further treatment. Functional controls of sonication and the reduction of water content in the sludge correlate with the obtained results. Ultrasound treatment has been shown to decrease the specific weight of the sludge sample both in pretreatment and treatment, therefore improving stabilization. In various experimental conditions, the weight of the sludge is reduced by a maximum of about 50%. Processed sludge transforms waste into a resource for the agricultural sector. Treatment processes have been optimized with low-energy operating principles. Additionally, besides utilizing energy-harvesting technology, plant operating processes have been optimized, accounting for approximately 55% of the consumption due to the aeration of active sludge. In addition, an extended analysis of ultrasonic wave propagation is proposed. Full article
(This article belongs to the Special Issue Numerical Optimization and Algorithms: 3rd Edition)
25 pages, 1149 KiB  
Article
Tuning a Proportional–Integral–Derivative Controller in a Programmable Logic Controller-Based Automatic Voltage Regulator System Using an Adaptive Artificial Bee Colony–Fuzzy Logic Algorithm
by Hüseyin Altınkaya and Dursun Ekmekci
Electronics 2024, 13(24), 5039; https://doi.org/10.3390/electronics13245039 (registering DOI) - 21 Dec 2024
Viewed by 305
Abstract
The voltage control of synchronous generators, particularly under varying load conditions, remains a significant and complex challenge in the field of engineering. Although various control methods have been implemented for automatic voltage regulator (AVR) systems to control the terminal voltage of synchronous generators, [...] Read more.
The voltage control of synchronous generators, particularly under varying load conditions, remains a significant and complex challenge in the field of engineering. Although various control methods have been implemented for automatic voltage regulator (AVR) systems to control the terminal voltage of synchronous generators, the PID-based control method continues to be one of the most basic and widely used approaches. Determining the optimal values for the Kp, Ki, and Kd values is essential to ensuring efficient and rapid performance in a PID controller. This study presents PLC-based PID controller tuning using an adaptive artificial bee colony–fuzzy logic (aABC-FL) approach for voltage control in a micro-hydro power plant installed as an experimental setup. The real-time control and monitoring of the system was conducted using an S7-1200 programmable logic controller (PLC) integrated with a totally integrated automation (TIA) portal interface and a SCADA screen. The aABC-Fuzzy design was developed using the MATLAB/Simulink platform, with PLC-MATLAB communication established through OPC UA and the KEPServerEX interface. The results obtained from experiments conducted under different load conditions showed that the proposed aABC-FL PID significantly minimized settling time and overshoot compared to the classical PLC-PID. Additionally, the proposed method not only provided a good dynamic response but also proved to be robust and reliable for real physical AVR systems. Full article
22 pages, 7805 KiB  
Article
Effects of Underwater Lighting Time on the Growth of Vallisneria spinulosa Yan and Its Water Restoration Process
by Mengyi Wei, Jinshan Zhao, Xiaolin Zhou, Fengdan Li, Min Zhao, Xiangyong Zheng, Ye Tang, Chang Yang, Zhenmin Jin and Suqing Wu
Water 2024, 16(24), 3697; https://doi.org/10.3390/w16243697 (registering DOI) - 21 Dec 2024
Viewed by 383
Abstract
Submerged macrophytes play a crucial role in the ecological restoration of water bodies, and their restoration capacity is closely related to the underwater lighting conditions. This study explored the effects of underwater lighting time on the growth characteristics of Vallisneria spinulosa Yan ( [...] Read more.
Submerged macrophytes play a crucial role in the ecological restoration of water bodies, and their restoration capacity is closely related to the underwater lighting conditions. This study explored the effects of underwater lighting time on the growth characteristics of Vallisneria spinulosa Yan (V. spinulosa) and its water restoration process. V. spinulosa achieved a higher Fv/Fm (0.64), ETRmax (10.43), chlorophyll content (0.85 mg/g), and removal efficiency of total phosphorus (0.37 × 10−3 g m−3 d−1) and a lower algal abundance with a longer lighting time (18 h every day). However, a higher removal efficiency of NH4+–N and TN was obtained with a shorter lighting time (6–12 h every day). The lighting time showed a significance influence on the microbial community of the V. spinulosa growth system, and the influence was significantly different in different regions. Temperature and electrical conductivity were the main environmental impact factors for the microbial community under different lighting times. The abundances of Proteobacteria, Bacteroidota, and Verrucomicrobia exhibited a great positive correlation with each other and a strong positive correlation with the two factors. In addition, the lighting time had a strongly significant correlation with the physical and chemical characteristics of the water environment (p < 0.001) and a significant correlation with the growth characteristics of V. spinulosa (p < 0.05). Full article
(This article belongs to the Special Issue Ecological Wastewater Treatment and Resource Utilization)
Show Figures

Figure 1

Figure 1
<p>Mean value of water properties in different treatment groups: (<b>a</b>) EC, (<b>b</b>) T, (<b>c</b>) pH, (<b>d</b>) DO. (V: <span class="html-italic">V. spinulosa</span> without auxiliary light source; LV: <span class="html-italic">V. spinulosa</span> + low light duration ratio; MV: <span class="html-italic">V. spinulosa</span> + medium light duration ratio; HV: <span class="html-italic">V. spinulosa</span> + high light duration ratio).</p>
Full article ">Figure 2
<p>The difference in removal load of (<b>a</b>) TN, (<b>b</b>) TP, (<b>c</b>) NH<sub>4</sub><sup>+</sup>–N, (<b>d</b>) PO<sub>4</sub><sup>3−</sup>–P, and (<b>e</b>) NO<sub>3</sub><sup>−</sup>–N in each experimental group under different light duration ratios. (V: <span class="html-italic">V. spinulosa</span> without auxiliary light source; LV: <span class="html-italic">V. spinulosa</span> + low light duration ratio; MV: <span class="html-italic">V. spinulosa</span> + medium light duration ratio; HV: <span class="html-italic">V. spinulosa</span> + high light duration ratio).</p>
Full article ">Figure 3
<p>The changes in (<b>a</b>) Fv/Fm and (<b>b</b>) ETRmax in each experimental group under different light duration ratios. (V: <span class="html-italic">V. spinulosa</span> without auxiliary light source; LV: <span class="html-italic">V. spinulosa</span> + low light duration ratio; MV: <span class="html-italic">V. spinulosa</span> + medium light duration ratio; HV: <span class="html-italic">V. spinulosa</span> + high light duration ratio).</p>
Full article ">Figure 4
<p>The changes in (<b>a</b>) Chl a + b content and (<b>b</b>) carotenoid content in each experimental group under different light duration ratios (V: <span class="html-italic">V. spinulosa</span> without auxiliary light source; LV: <span class="html-italic">V. spinulosa</span> + low light duration ratio; MV: <span class="html-italic">V. spinulosa</span> + medium light duration ratio; HV: <span class="html-italic">V. spinulosa</span> + high light duration ratio).</p>
Full article ">Figure 5
<p>The changes in (<b>a</b>) plant height, root length, and (<b>b</b>) biomass in each experimental group under different light duration ratios. (V: <span class="html-italic">V. spinulosa</span> without auxiliary light source; LV: <span class="html-italic">V. spinulosa</span> + low light duration ratio; MV: <span class="html-italic">V. spinulosa</span> + medium light duration ratio; HV: <span class="html-italic">V. spinulosa</span> + high light duration ratio).</p>
Full article ">Figure 6
<p>CLSM diagram of leaf–biofilm complex in different light duration ratios. (<b>a</b>) LV: <span class="html-italic">V. spinulosa</span> + low light duration ratio, (<b>b</b>) MV: <span class="html-italic">V. spinulosa</span> + medium light duration ratio, and (<b>c</b>) HV: <span class="html-italic">V. spinulosa</span> + high light duration ratio. Red is EPS polysaccharide stained with Texas red, green is protein stained with FITC, and bright blue is DNA stained with DAPI.</p>
Full article ">Figure 7
<p>Venn diagram of gate distribution in different samples. (VW: V–Water, LVW: LV–Water, MVW: MV–Water, HVW: HV–Water, LVL: LV–Leaf surface, MVL: MV–Leaf surface, HVL: HV–Leaf surface, VS: V–Sediment, LVS: LV–Sediment, MVS: MV–Sediment, HVS: HV–Sediment).</p>
Full article ">Figure 8
<p>Microbial community analysis: (<b>a</b>) the percentage of community abundance at the phylum level; (<b>b</b>) heatmap of bacterial community at the genus level.</p>
Full article ">Figure 9
<p>Microbial PLS−DA analysis (gate level).</p>
Full article ">Figure 10
<p>(<b>a</b>) LEfSe analysis of microbial abundance in LV, MV, and HV and (<b>b</b>) microbial markers (LDA threshold &gt; 2).</p>
Full article ">Figure 11
<p>RDA analysis of microbial community structure and environmental factors.</p>
Full article ">Figure 12
<p>Partial least squares path model (PLS–PM) of PSII between water characteristics, water nutrients, <span class="html-italic">V. spinulosa</span> characteristics, and microorganisms. The blue and red lines represent positive and negative paths, respectively, and the solid and dotted lines represent significant and non–significant correlations, respectively. The significance level is represented by an asterisk: *** <span class="html-italic">p</span> ≤ 0.001, ** 0.001 &lt; <span class="html-italic">p</span> ≤ 0.01, * 0.01 &lt; <span class="html-italic">p</span> ≤ 0.05. The latent variable (red square) is represented by a measurement variable (yellow square). The values are their respective weights.</p>
Full article ">
17 pages, 5298 KiB  
Article
Stratification Effects on Estuarine Mixing: Comparative Analysis of the Danshui Estuary and a Thermal Discharge Outlet
by Yaozhao Zhong and Hwa Chien
J. Mar. Sci. Eng. 2024, 12(12), 2353; https://doi.org/10.3390/jmse12122353 (registering DOI) - 21 Dec 2024
Viewed by 282
Abstract
Estuaries serve as transitional zones between rivers and the ocean, and their mixed dynamic characteristics are crucial for the transport, transformation, and cycling of materials. This study investigates the mixing characteristics and their dominant factors in the Danshui Estuary and thermal discharge outlets [...] Read more.
Estuaries serve as transitional zones between rivers and the ocean, and their mixed dynamic characteristics are crucial for the transport, transformation, and cycling of materials. This study investigates the mixing characteristics and their dominant factors in the Danshui Estuary and thermal discharge outlets through field measurements. Based on CTD (Conductance Temperature Depth) profiles and nutrient concentration measurements, the Danshui Estuary exhibited significant stratification during the October 2016 cruise, while vertical mixing was uniform during the March 2017 cruise. Vertical mixing was suppressed during stratification, but the nutrient concentration varied with salinity in a manner that was similar to non-stratified conditions, generally conforming to the theoretical dilution curve, which means physical mixing dominated here, indicating that horizontal mixing is predominant in the Danshui Estuary. The spatial scale calibrated horizontal dispersion coefficients were measured as 9.16 ± 1.57 m2 s−1 and 11.84 ± 1.71 m2 s−1 for stratified and non-stratified conditions, respectively, highlighting the Danshui Estuary’s strong horizontal mixing. Thermal discharge outlets are an important type of estuarine environment in non-natural estuaries. The 3D thermohaline structure measured by the underway CTD revealed an upwelling of cold and high-salinity water during the flood tide. The calculated Richardson number during the flood tide was approximately 0.7, indicating a very strong stratification effect. The horizontal dispersion coefficients calibrated by spatial scale showed no significant difference between different tides (flood tide: 0.53 ± 0.18 m2 s−1, ebb tide: 0.46 ± 0.17 m2 s−1). Therefore, the slower temperature decay during the flood tide, as reflected by the e-folding time (flood tide: 4.19 ± 2.33 min, ebb tide: 2.14 ± 0.40 min), is attributed to the strong stratification. Based on these findings, it is recommended that the power plant mitigates the impact of waste heat on the marine environment by increasing discharge during the ebb tide and reducing it during the flood tide. Full article
(This article belongs to the Section Physical Oceanography)
Show Figures

Figure 1

Figure 1
<p>Study areas. There are two red boxes in (<b>a</b>). The box on the north side shows the location of the Danshui Estuary; details are shown in (<b>b</b>). The box on the south side shows the location of the thermal discharge area of the nuclear power plant; details are shown in (<b>c</b>). Asterisks (*) in (<b>b</b>) show the locations where the CTD measurements and water sample collections were conducted. The CTD data collected from the stations marked as asterisks with a red circle in (<b>b</b>) was further analyzed in <a href="#sec3dot1-jmse-12-02353" class="html-sec">Section 3.1</a>. Dots (·) in (<b>c</b>) show the locations where the underway CTD measurements were conducted. A weather transmitter is installed at the point marked with the red pentagram. The red triangle (△) shows the location of an up-looking ADCP.</p>
Full article ">Figure 2
<p>Structure of self-developed sea surface drifter with a temperature detector at the bottom.</p>
Full article ">Figure 3
<p>Temperature and salinity profiles of Danshui Estuary. (<b>a</b>,<b>c</b>): temperature profiles. (<b>b</b>,<b>d</b>): salinity profiles. The CTD data for this figure were collected from the stations marked as asterisks with a red circle in <a href="#jmse-12-02353-f001" class="html-fig">Figure 1</a>b. The horizontal axis represents the distance of each station from the estuary mouth. The <span class="html-italic">x</span>-markers on the graph indicate the actual sampling locations and their corresponding water depths. ORII represents Ocean Research Vessel No. 2, and 20161005 (20170322) means the date of 5 October 2016 (22 March 2017).</p>
Full article ">Figure 4
<p>Chlorophyll and dissolved oxygen concentration profiles of Danshui Estuary. The chlorophyll and DO concentration data for this figure were collected from the stations marked as asterisks with a red circle in <a href="#jmse-12-02353-f001" class="html-fig">Figure 1</a>b. The horizontal axis represents the distance of each station from the estuary mouth. The x-markers on the graph indicate the actual sampling locations and their corresponding water depths. ORII represents Ocean Research Vessel No. 2, and 20161005 (20170322) means the date of 5 October 2016 (22 March 2017).</p>
Full article ">Figure 5
<p>3D thermohaline structure of the thermal discharge area. (<b>a</b>,<b>b</b>) around the moment of maximum flow during the flood tide, and (<b>c</b>,<b>d</b>) around the moment of maximum flow during the ebb tide.</p>
Full article ">Figure 6
<p>Relationships between DIN concentration and salinity around the Danshui Estuary. (<b>a</b>): October 2016 cruise. (<b>b</b>): March 2017 cruise. The blue * represent scatters of DIN versus salinity and the black solid lines represent fitting curves. The figure includes all the water sample measurement data from the surface, middle, and bottom layers during each cruise. ORII represents Ocean Research Vessel No. 2, and 20161005 (20170322) means the date of 5 October 2016 (22 March 2017).</p>
Full article ">Figure 7
<p>Fitting curves of water temperature attenuation around the thermal discharge area. The blue points are the water temperature measured by sea surface drifters, and the red solid lines are the fitting curves.</p>
Full article ">Figure 8
<p>Horizontal dispersion coefficients around the Danshui Estuary measured by sea surface drifter array. (<b>a</b>,<b>b</b>): October 2016 cruise. (<b>c</b>–<b>f</b>): March 2017 cruise. The red solid lines represent the trajectories of the drifters, and the asterisks (*) indicate the release points. The symbols △, ×, □, and ☆ along the trajectories denote the positions of the drifters at 10,000, 20,000, 30,000, and 40,000 s after release, respectively. The lower left corner of each panel provides the dispersion coefficient (without spatial scale calibration) calculated by Equation (1), the spatial scale calculated by Equation (5), and the IDs of the three drifters.</p>
Full article ">Figure 9
<p>Horizontal dispersion coefficients around the thermal discharge outlet measured by sea surface drifter array. (<b>a</b>–<b>j</b>): flood tide. (<b>k</b>–<b>q</b>): ebb tide. The red solid lines represent the trajectories of the drifters, and the asterisks (*) indicate the release points. The upper right corner of each panel provides the dispersion coefficient (without spatial scale calibration) calculated by Equation (1) and the spatial scale calculated by Equation (5). The lower left corner shows the IDs of the three drifters.</p>
Full article ">Figure 10
<p>Relationship between horizontal dispersion and the drifter array’s spatial scale for (<b>a</b>) the Danshui Estuary and (<b>b</b>) the thermal discharge outlet. The blue * represent scatters of <span class="html-italic">k</span> versus <span class="html-italic">l</span> and the black dot lines represent fitting curves.</p>
Full article ">
37 pages, 1306 KiB  
Systematic Review
Injected Fuel Mass and Flow Rate Control in Internal Combustion Engines: A Systematic Literature Review
by Alessandro Ferrari, Simona Gurrì and Oscar Vento
Energies 2024, 17(24), 6455; https://doi.org/10.3390/en17246455 (registering DOI) - 21 Dec 2024
Viewed by 546
Abstract
Advancements in fuel injection systems have dramatically improved the precision of controlling injected fuel mass or flow rate; a key factor in optimizing internal combustion engine (ICE) performance, emissions control, and fuel efficiency. This review systematically analyzes 145 scientific research papers from the [...] Read more.
Advancements in fuel injection systems have dramatically improved the precision of controlling injected fuel mass or flow rate; a key factor in optimizing internal combustion engine (ICE) performance, emissions control, and fuel efficiency. This review systematically analyzes 145 scientific research papers from the last two decades, including older foundational works, tracing the evolution of injected mass control from early Bosch and Zeuch meters to advanced machine learning or physical models. This study draws upon research collected from the most reputable databases. Through both qualitative and quantitative analyses, the state-of-the-art of these systems is presented, and key innovations are highlighted regarding advanced control algorithms and real-time feedback mechanisms under various operational conditions such as high or transient loads and multi-stage injection strategies. Special attention is given to challenges in maintaining precise control with alternative fuels like biodiesel, hydrogen, or synthetic fuels, which exhibit different physical properties compared to traditional fuels. The findings emphasize the need for further research on injection control, especially in light of stringent emissions regulations. Improving these systems for next-generation ICEs is a key point for achieving cleaner, more efficient combustion and bridging the sustainability gap between traditional and future mobility solutions. Full article
(This article belongs to the Special Issue Emission Control Technology in Internal Combustion Engines)
Show Figures

Figure 1

Figure 1
<p>New registered cars per year in EU-27 and the percentage of diesel cars. Data from ICCT European Vehicle Market Statistics Pocketbook [<a href="#B3-energies-17-06455" class="html-bibr">3</a>].</p>
Full article ">Figure 2
<p>Different fuel injection arrangements—(<b>a</b>) single-point PFI; (<b>b</b>) multi-point PFI; (<b>c</b>) direct in-cylinder injection (DI).</p>
Full article ">Figure 3
<p>Flow chart adapted from PRISMA 2020 for systematic reviews, which included only searches of databases.</p>
Full article ">Figure 4
<p>Number of publications considered per year.</p>
Full article ">Figure 5
<p>Journal rankings.</p>
Full article ">Figure 6
<p>Global distribution of research activity based on methodology categories. The colors represent the category for which the given country has contributed the most.</p>
Full article ">Figure 7
<p>Citations for the papers published in a given year until now. The peak in citations is in 2014.</p>
Full article ">Figure 8
<p>Real measurement of the rate of injection for a diesel common rail injector.</p>
Full article ">Figure 9
<p>Scheme of a solenoid injector.</p>
Full article ">Figure 10
<p>Scheme of a direct-acting piezoelectric injector.</p>
Full article ">Figure 11
<p>Scheme of common rail system.</p>
Full article ">Figure 12
<p>Scheme of a GDI injector.</p>
Full article ">Figure 13
<p>Bosch measurement device.</p>
Full article ">Figure 14
<p>Zeuch approach measurement principle for injected mass.</p>
Full article ">Figure 15
<p>Schematics of the regression modeling using artificial neural networks.</p>
Full article ">
19 pages, 5621 KiB  
Article
Modified Kapok Fibers (Ceiba pentandra (L.) Gaerth) for Oil Spill Remediation
by Leonardo M. T. M. Oliveira, Eduardo J. S. Fonseca, Vanderson B. Bernardo, Carmem L. P. S. Zanta, Laís F. A. M. Oliveira, Jennifer N. S. R. de Oliveira, Samuel T. de Souza and José Leandro da Silva Duarte
Appl. Sci. 2024, 14(24), 11995; https://doi.org/10.3390/app142411995 - 21 Dec 2024
Viewed by 460
Abstract
The search for efficient oil spill remediation techniques leads to the use of physical, chemical, and biological methods, featuring both natural and modified lipophilic materials. Kapok fibers (Ceiba pentandra (L.) Gaerth) have been studied as a result of their unusual natural oil [...] Read more.
The search for efficient oil spill remediation techniques leads to the use of physical, chemical, and biological methods, featuring both natural and modified lipophilic materials. Kapok fibers (Ceiba pentandra (L.) Gaerth) have been studied as a result of their unusual natural oil sorption capacity, which can be improved even further through physical or chemical treatments that augment their rugosity and alter their functional properties. Furthermore, the exact role of fiber morphology is not completely clear regarding the sorption process. Hence, this study investigated the efficacy of kapok fibers using different treatments, based on chemical and physical approaches, and characterized using advanced techniques (FTIR, SEM, AFM), aiming to improve the understanding of application possibilities in oil contamination scenarios. The results indicate that treatments using a low thermal intensity and low concentration do not lead to variation in sorption properties nor in surface structural features. Fiber rugosity varied from 4.40 to 12.35 nm, whereas an excessive increase in roughness was observed when the material was subject to more extreme conditions, such as a temperature of 120 °C and high concentrations (2.0 M) of both acid or alkali, accompanied by a loss in functionality and affecting the material sorption capacity. Thus, the study provides conditions to suggest that these treatments are not necessary for this type of material when inserted into sorption processes. Full article
(This article belongs to the Special Issue New Approaches to Water Treatment: Challenges and Trends)
Show Figures

Figure 1

Figure 1
<p>Preparation flowchart. Initial collection and preparation stage, with thermal, acid, and alkali activations and applications.</p>
Full article ">Figure 2
<p>(<b>a</b>) Apparatus used to hold the kapok fibers inside an Erlenmeyer flask; (<b>b</b>) Kapok sample forcibly kept in contact with treatment solution (acid or alkaline).</p>
Full article ">Figure 3
<p>(<b>a</b>) Sorptive capacities of kapok fiber submitted to thermal treatment, (<b>b</b>) acid treatment, and (<b>c</b>) alkali treatment.</p>
Full article ">Figure 4
<p>(<b>a</b>) FTIR spectra of the kapok samples treated at different temperatures. (<b>b</b>) Acid activation and (<b>c</b>) alkali activation.</p>
Full article ">Figure 5
<p>Fibers images without treatment (<b>a</b>) and treated at (<b>b</b>) 60, (<b>c</b>) 90, and (<b>d</b>) 120 °C.</p>
Full article ">Figure 6
<p>SEM micrographs of kapok fibers subject to acid treatments. (<b>a</b>) Lumen structure—HCl 0.1 mol/L; (<b>b</b>) surface—HCl 0.1 mol/L; (<b>c</b>) lumen structure—HCl 2.0 mol/L; (<b>d</b>) surface—HCl 2.0 mol/L. (<b>e</b>) Fissures on the tubular structure promoted by acid (2.0 mol/L HCl).</p>
Full article ">Figure 7
<p>Micrographs with different magnifications of kapok fibers treated with NaOH solutions. Treatment with 0.1 mol/L: (<b>a</b>) lumen structure (1000×), (<b>b</b>) surface (5000×), (<b>c</b>) disposition and condition of the fiber (300×). Treatment with 2.0 mol/L: (<b>d</b>) lumen structure (2400×), (<b>e</b>) surface (5000×), (<b>f</b>) disposition and condition of the fiber (240×), (<b>g</b>) advanced mercerization process on the fiber caused by the alkaline treatment (2.0 mol/L NaOH).</p>
Full article ">Figure 8
<p>Average roughness (Ra) of natural and post-treatment kapok fibers. (<b>a</b>) Average values of roughness (Ra) of all kapok fibers analyzed. (<b>b</b>–<b>h</b>) Topographical images obtained using AFM of the fibers: (<b>b</b>) in natura, (<b>c</b>) treated at 60 °C, (<b>d</b>) treated at 120 °C, (<b>e</b>) treated with HCl 0.1 mol/L, (<b>f</b>) treated with HCl 2.0 mol/L, (<b>g</b>) treated with NaOH 0.1 mol/L, and (<b>h</b>) treated with NaOH 2.0 mol/L.</p>
Full article ">Figure 9
<p>Average tensile strength for natural fibers and under treatments in the most extreme conditions tested in this work.</p>
Full article ">
Back to TopTop