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Search Results (469)

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Keywords = Thermal Environmental Index

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18 pages, 3060 KiB  
Article
Unveiling the Impact of Climatic Factors on the Distribution Patterns of Caragana spp. in China’s Three Northern Regions
by Weiwei Zhao, Yujia Liu, Yanxia Li, Chunjing Zou and Hideyuki Shimizu
Plants 2025, 14(15), 2368; https://doi.org/10.3390/plants14152368 - 1 Aug 2025
Abstract
Understanding the impacts of climate change on species’ geographic distributions is fundamental for biodiversity conservation and resource management. As a key plant group for ecological restoration and windbreak and sand fixation in arid and semi-arid ares in China’s Three Northern Regions (Northeast, North, [...] Read more.
Understanding the impacts of climate change on species’ geographic distributions is fundamental for biodiversity conservation and resource management. As a key plant group for ecological restoration and windbreak and sand fixation in arid and semi-arid ares in China’s Three Northern Regions (Northeast, North, and Northwest China), Caragana spp. exhibit distribution patterns whose regulatory mechanisms by environmental factors remain unclear, with a long-term lack of climatic explanations influencing their spatial distribution. This study integrated 2373 occurrence records of 44 Caragana species in China’s Three Northern Regions with four major environmental variable categories. Using the Biomod2 ensemble model, current and future climate scenario-based suitable habitats for Caragana spp. were predicted. This study innovatively combined quantitative analyses with Kira’s thermal indexes (warmth index, coldness index) and Wenduo Xu’s humidity index (HI) to elucidate species-specific relationships between distribution patterns and hydrothermal climatic constraints. The main results showed that (1) compared to other environmental factors, climate is the key factor affecting the distribution of Caragana spp. (2) The current distribution centroid of Caragana spp. is located in Alxa Left Banner, Inner Mongolia. In future scenarios, the majority of centroids will shift toward lower latitudes. (3) The suitable habitats for Caragana spp. will expand overall under future climate scenarios. High-stress scenarios exhibit greater spatial changes than low-stress scenarios. (4) Hydrothermal requirements varied significantly among species in China’s Three Northern Regions, and 44 Caragana species can be classified into five distinct types based on warmth index (WI) and humidity index (HI). The research findings will provide critical practical guidance for ecological initiatives such as the Three-North Shelterbelt Program and the restoration and management of degraded ecosystems in arid and semi-arid regions under global climate change. Full article
(This article belongs to the Section Plant Ecology)
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24 pages, 6731 KiB  
Article
Combined Impacts of Acute Heat Stress on the Histology, Antioxidant Activity, Immunity, and Intestinal Microbiota of Wild Female Burbot (Lota Lota) in Winter: New Insights into Heat Sensitivity in Extremely Hardy Fish
by Cunhua Zhai, Yutao Li, Ruoyu Wang, Haoxiang Han, Ying Zhang and Bo Ma
Antioxidants 2025, 14(8), 947; https://doi.org/10.3390/antiox14080947 (registering DOI) - 31 Jul 2025
Abstract
Temperature fluctuations caused by climate change and global warming pose a threat to fish. The burbot (lota lota) population is particularly sensitive to increased water temperature, but the systematic impacts of high-temperature exposure on their liver and intestinal health remain unclear. [...] Read more.
Temperature fluctuations caused by climate change and global warming pose a threat to fish. The burbot (lota lota) population is particularly sensitive to increased water temperature, but the systematic impacts of high-temperature exposure on their liver and intestinal health remain unclear. In January of 2025, we collected wild adult burbot individuals from the Ussuri River (water temperature: about 2 °C), China. The burbot were exposed to 2 °C, 7 °C, 12 °C, 17 °C, and 22 °C environments for 96 h; then, the liver and intestinal contents were subsequently collected for histopathology observation, immunohistochemistry, biochemical index assessment, and transcriptome/16S rDNA sequencing analysis. There was obvious liver damage including hepatocyte necrosis, fat vacuoles, and cellular peripheral nuclei. Superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities were elevated and subsequently decreased. Additionally, the malondialdehyde (MDA) level significantly increased with increasing temperature. These results indicate that 7 °C (heat stress temperature), 12 °C (tipping point for normal physiological metabolism status), 17 °C (tipping point for individual deaths), and 22 °C (thermal limit) are critical temperatures in terms of the physiological response of burbot during their breeding period. In the hepatic transcriptome profiling, 6538 differentially expressed genes (DEGs) were identified, while KEGG enrichment analysis showed that high-temperature stress could affect normal liver function by regulating energy metabolism, immune, and apoptosis-related pathways. Microbiomics also revealed that acute heat stress could change the intestinal microbe community structure. Additionally, correlation analysis suggested potential regulatory relationships between intestinal microbe taxa and immune/apoptosis-related DEGs in the liver. This study revealed the potential impact of environmental water temperature changes in cold habitats in winter on the physiological adaptability of burbot during the breeding period and provides new insights for the ecological protection of burbot in the context of global climate change and habitat warming. Full article
(This article belongs to the Special Issue Antioxidant Response in Aquatic Animals)
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18 pages, 3967 KiB  
Article
A Thorough Investigation of the Mechanism of theAntagonistic Effect Between Phosphorus and Basic Oxide-Forming Minerals as Flame Retardants of PolymericComposite Coatings
by Evangelia Mitropoulou, Georgios N. Mathioudakis, Amaia Soto Beobide, Athanasios Porfyris, Vassilios Dracopoulos, Kerim Kılınç, Theodosios Chatzinikolaou, Deniz Savci, Cem Gunesoglu, Joannis Kallitsis and George A. Voyiatzis
Coatings 2025, 15(8), 886; https://doi.org/10.3390/coatings15080886 - 30 Jul 2025
Abstract
Halogenated flame retardants have been amongst the most widely used and effective solutions for enhancing fire resistance. However, their use is currently strictly regulated due to serious health and environmental concerns. In this context, phosphorus-based and mineral flame retardants have emerged as promising [...] Read more.
Halogenated flame retardants have been amongst the most widely used and effective solutions for enhancing fire resistance. However, their use is currently strictly regulated due to serious health and environmental concerns. In this context, phosphorus-based and mineral flame retardants have emerged as promising alternatives. Despite this, their combined use is neither straightforward nor guaranteed to be effective. This study scrutinizes the interactions between these two classes of flame retardants (FR) through a systematic analysis aimed at elucidating the antagonistic pathways that arise from their coexistence. Specifically, this study focuses on two inorganic fillers, mineral huntite and chemically precipitated magnesium hydroxide, both of which produce basic oxides upon thermal decomposition. These fillers were incorporated into a poly(butylene terephthalate) (PBT) matrix to be utilized as advanced-mattress FR coating fabric and were subjected to a series of flammability tests. The pyrolysis products of the prepared polymeric composite compounds were isolated and thoroughly characterized using a combination of analytical techniques. Thermogravimetric analysis (TGA) and differential thermogravimetric analysis (dTGA) were employed to monitor decomposition behavior, while the char residues collected at different pyrolysis stages were examined spectroscopically, using FTIR-ATR and Raman spectroscopy, to identify their structure and the chemical reactions that led to their formation. X-ray diffraction (XRD) experiments were also conducted to complement the spectroscopic findings in the chemical composition of the resulting char residues and to pinpoint the different species that constitute them. The morphological changes of the char’s structure were monitored by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). Finally, the Limited Oxygen Index (LOI) and UL94 (vertical sample mode) methods were used to assess the relative flammability of the samples, revealing a significant drop in flame retardancy when both types of flame retardants are present. This reduction is attributed to the neutralization of acidic phosphorus species by the basic oxides generated during the decomposition of the basic inorganic fillers, as confirmed by the characterization techniques employed. These findings underscore the challenge of combining organophosphorus with popular flame-retardant classes such as mineral or basic metal flame retardants, offering insight into a key difficulty in formulating next-generation halogen-free flame-retardant composite coatings. Full article
(This article belongs to the Special Issue Innovative Flame-Retardant Coatings for High-Performance Materials)
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25 pages, 11642 KiB  
Article
Non-Invasive Estimation of Crop Water Stress Index and Irrigation Management with Upscaling from Field to Regional Level Using Remote Sensing and Agrometeorological Data
by Emmanouil Psomiadis, Panos I. Philippopoulos and George Kakaletris
Remote Sens. 2025, 17(14), 2522; https://doi.org/10.3390/rs17142522 - 20 Jul 2025
Viewed by 390
Abstract
Precision irrigation plays a crucial role in managing crop production in a sustainable and environmentally friendly manner. This study builds on the results of the GreenWaterDrone project, aiming to estimate, in real time, the actual water requirements of crop fields using the crop [...] Read more.
Precision irrigation plays a crucial role in managing crop production in a sustainable and environmentally friendly manner. This study builds on the results of the GreenWaterDrone project, aiming to estimate, in real time, the actual water requirements of crop fields using the crop water stress index, integrating infrared canopy temperature, air temperature, relative humidity, and thermal and near-infrared imagery. To achieve this, a state-of-the-art aerial micrometeorological station (AMMS), equipped with an infrared thermal sensor, temperature–humidity sensor, and advanced multispectral and thermal cameras is mounted on an unmanned aerial system (UAS), thus minimizing crop field intervention and permanently installed equipment maintenance. Additionally, data from satellite systems and ground micrometeorological stations (GMMS) are integrated to enhance and upscale system results from the local field to the regional level. The research was conducted over two years of pilot testing in the municipality of Trifilia (Peloponnese, Greece) on pilot potato and watermelon crops, which are primary cultivations in the region. Results revealed that empirical irrigation applied to the rhizosphere significantly exceeded crop water needs, with over-irrigation exceeding by 390% the maximum requirement in the case of potato. Furthermore, correlations between high-resolution remote and proximal sensors were strong, while associations with coarser Landsat 8 satellite data, to upscale the local pilot field experimental results, were moderate. By applying a comprehensive model for upscaling pilot field results, to the overall Trifilia region, project findings proved adequate for supporting sustainable irrigation planning through simulation scenarios. The results of this study, in the context of the overall services introduced by the project, provide valuable insights for farmers, agricultural scientists, and local/regional authorities and stakeholders, facilitating improved regional water management and sustainable agricultural policies. Full article
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26 pages, 7157 KiB  
Article
Urban Heat Islands and Land-Use Patterns in Zagreb: A Composite Analysis Using Remote Sensing and Spatial Statistics
by Dino Bečić and Mateo Gašparović
Land 2025, 14(7), 1470; https://doi.org/10.3390/land14071470 - 15 Jul 2025
Viewed by 798
Abstract
Urban heat islands (UHIs) present a growing environmental issue in swiftly urbanizing regions, where impermeable surfaces and a lack of vegetation increase local temperatures. This research analyzes the spatial distribution of urban heat islands in Zagreb, Croatia, utilizing remote sensing data, urban planning [...] Read more.
Urban heat islands (UHIs) present a growing environmental issue in swiftly urbanizing regions, where impermeable surfaces and a lack of vegetation increase local temperatures. This research analyzes the spatial distribution of urban heat islands in Zagreb, Croatia, utilizing remote sensing data, urban planning metrics, and spatial-statistical analysis. Composite rasters of land surface temperature (LST) and the Normalized Difference Vegetation Index (NDVI) were generated from four cloud-free Landsat 9 images obtained in the summer of 2024. The data were consolidated into regulatory planning units through zonal statistics, facilitating the evaluation of the impact of built-up density and designated green space on surface temperatures. A composite UHI index was developed by combining normalized land surface temperature (LST) and normalized difference vegetation index (NDVI) measurements, while spatial clustering was examined with Local Moran’s I and Getis-Ord Gi*. The results validate spatial patterns of heat intensity, with high temperatures centered in densely built residential areas. This research addresses the gap in past UHI studies by providing a reproducible approach for detecting thermal stress zones, linking satellite data with spatial planning variables. The results support the development of localized climate adaptation methods and highlight the importance of integrating green infrastructure into urban planning methodologies. Full article
(This article belongs to the Special Issue Urban Land Use Change and Its Spatial Planning)
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19 pages, 6665 KiB  
Article
Enhanced Flame Retardancy of Silica Fume-Based Geopolymer Composite Coatings Through In Situ-Formed Boron Phosphate from Doped Zinc Phytate and Boric Acid
by Yachao Wang, Yufei Qu, Chuanzhen Wang and Juan Dou
Minerals 2025, 15(7), 735; https://doi.org/10.3390/min15070735 - 14 Jul 2025
Viewed by 171
Abstract
Silica fume-based geopolymer composite coatings, an approach to using metallurgical solid waste, exert flame retardancy with ecological, halogen-free, and environmentally friendly advantages, but their fire resistance needs to be improved further. Herein, a silica fume-based geopolymer composite flame-retardant coating was designed by doping [...] Read more.
Silica fume-based geopolymer composite coatings, an approach to using metallurgical solid waste, exert flame retardancy with ecological, halogen-free, and environmentally friendly advantages, but their fire resistance needs to be improved further. Herein, a silica fume-based geopolymer composite flame-retardant coating was designed by doping boric acid (BA), zinc phytate (ZnPA), and melamine (MEL). The results of a cone calorimeter demonstrated that appropriate ZnPA and BA significantly enhanced its flame retardancy, evidenced by the peak heat release rate (p-HRR) decreasing from 268.78 to 118.72 kW·m−2, the fire performance index (FPI) increasing from 0.59 to 2.83 s·m2·kW−1, and the flame retardancy index increasing from 1.00 to 8.48, respectively. Meanwhile, the in situ-formed boron phosphate (BPO4) facilitated the residual resilience of the fire-barrier layer. Furthermore, the pyrolysis kinetics indicated that the three-level chemical reactions governed the pyrolysis of the coatings. BPO4 made the pyrolysis Eα climb from 94.28 (P5) to 127.08 (B3) kJ·mol−1 with temperatures of 731–940 °C, corresponding to improved thermal stability. Consequently, this study explored the synergistic flame-retardant mechanism of silica fume-based geopolymer coatings doped with ZnPA, BA, and MEL, providing an efficient strategy for the high-value-added recycling utilization of silica fume. Full article
(This article belongs to the Topic Innovative Strategies to Mitigate the Impact of Mining)
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27 pages, 7546 KiB  
Article
Upcycling Luffa cylindrica (Luffa Sponge) Seed Press Cake as a Functional Ingredient for Meat Substitute Formulations
by Génica Lawrence, Thaïna Josy, Ewa Pejcz, Agata Wojciechowicz-Budzisz, Remigiusz Olędzki, Katarzyna Górska, Adam Zając, Guylène Aurore and Joanna Harasym
Appl. Sci. 2025, 15(14), 7753; https://doi.org/10.3390/app15147753 - 10 Jul 2025
Viewed by 256
Abstract
In the current context of environmental concerns and the search for sustainable food solutions, this study investigated the valorization of Luffa cylindrica seed press cake, a waste byproduct from oil extraction, as a functional ingredient for meat substitute formulations. The research systematically characterized [...] Read more.
In the current context of environmental concerns and the search for sustainable food solutions, this study investigated the valorization of Luffa cylindrica seed press cake, a waste byproduct from oil extraction, as a functional ingredient for meat substitute formulations. The research systematically characterized the functional and bioactive properties of L. cylindrica seed press cake powder (LP) and its blends with tapioca flour (TF) at ratios of 30–70%. Techno-functional analyses included: hydration properties (water holding capacity, water absorption capacity, water absorption index, water solubility index, swelling power, oil absorption capacity); rheological characteristics; bioactive profiling through antioxidant assays (DPPH, ABTS, FRAP); and reducing sugar content determination. Meat substitute formulations were developed using an LP30/TF70 blend combined with coral lentils, red beet powder, and water, followed by a sensory evaluation and storage stability assessment. Pure L. cylindrica powder exhibited the highest water holding capacity (3.62 g H2O/g) and reducing sugar content (8.05 mg GE/g), while tapioca flour showed superior swelling properties. The blends demonstrated complementary functional characteristics, with the LP30/TF70 formulation selected for meat substitute development based on optimal textural properties. The sensory evaluation revealed significant gender differences in acceptance, with women rating the product substantially higher than men across all attributes. The study successfully demonstrated the feasibility of transforming agricultural waste into a valuable functional ingredient, contributing to sustainable food production and representing the first comprehensive evaluation of L. cylindrica seed press cake for food applications. However, the study revealed limitations, including significant antioxidant loss during thermal processing (80–85% reduction); a preliminary sensory evaluation with limited participants showing gender-dependent acceptance; and a reliance on locally available tapioca flour, which may limit global applicability. Future research should focus on processing optimization to preserve bioactive compounds, comprehensive sensory studies with diverse populations, and an investigation of alternative starch sources to enhance the worldwide implementation of this valorization approach. Full article
(This article belongs to the Special Issue Processing and Application of Functional Food Ingredients)
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21 pages, 3527 KiB  
Article
Effects of Environmental Temperature Variation on the Spatio-Temporal Shoaling Behaviour of Adult Zebrafish (Danio rerio): A Two- and Three-Dimensional Analysis
by Mattia Toni, Flavia Frabetti, Gabriella Tedeschi and Enrico Alleva
Animals 2025, 15(14), 2006; https://doi.org/10.3390/ani15142006 - 8 Jul 2025
Viewed by 319
Abstract
Global warming is driving significant changes in aquatic ecosystems, where temperature fluctuations influence biological processes across multiple levels of organisation. As ectothermic organisms, fish are particularly susceptible, with even minor thermal shifts affecting their metabolism, behaviour, and overall fitness. Understanding these responses is [...] Read more.
Global warming is driving significant changes in aquatic ecosystems, where temperature fluctuations influence biological processes across multiple levels of organisation. As ectothermic organisms, fish are particularly susceptible, with even minor thermal shifts affecting their metabolism, behaviour, and overall fitness. Understanding these responses is essential for evaluating the ecological and evolutionary consequences of climate change. This study investigates the effects of acute (4-day) and chronic (21-day) exposure to three temperature regimes—18 °C (low), 26 °C (control), and 34 °C (high)—on the spatio-temporal shoaling behaviour of adult zebrafish (Danio rerio). Groups of four fish were tested for six minutes in water maintained at the same temperature as their prior acclimation. Shoaling behaviour was assessed by analysing shoal structure—encompassing shoal dimensions and cohesion—as well as spatial positioning. Parameters measured included inter-fish distance, shoal volume, shoal area, homogeneity index, distance to the centroid, and the shoal’s vertical and horizontal distribution. Results revealed complex behavioural changes influenced by both temperature and duration of exposure. At 18 °C, zebrafish showed a marked preference for the bottom zone and exhibited no significant temporal modulation in exploratory behaviour—patterns indicative of heightened anxiety-like responses. In contrast, exposure to 34 °C resulted in increased shoal cohesion, particularly under chronic conditions, and a progressive increase in environmental exploration over the six-minute test period. This enhancement in exploratory activity was especially evident when compared to the first minute of the test and was characterised by greater vertical movement—reflected in the increased use of the upper zone—and broader horizontal exploration, including more frequent occupation of peripheral areas. These findings align with previous research linking thermal variation to neurobiological and proteomic alterations in zebrafish. By elucidating how temperature modulates social behaviour in ectotherms, this study offers valuable insights into the potential behavioural impacts of climate change on aquatic ecosystems. Full article
(This article belongs to the Section Aquatic Animals)
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14 pages, 4788 KiB  
Article
Heat Impact Assessment and Heat Prevention Suggestions for Thermal Comfort at Large-Area and Long-Duration Outdoor Sport Events in Taiwan
by Si-Yu Yu, Tzu-Ping Lin and Andreas Matzarakis
Atmosphere 2025, 16(7), 805; https://doi.org/10.3390/atmos16070805 - 1 Jul 2025
Viewed by 370
Abstract
This study aims to (1) analyze thermal comfort at outdoor sport events held outside of fixed venues or locations; (2) establish a method for evaluating environmental thermal comfort for large-scale, long-term outdoor activities; and (3) provide suggestions for the arrangement of shifts in [...] Read more.
This study aims to (1) analyze thermal comfort at outdoor sport events held outside of fixed venues or locations; (2) establish a method for evaluating environmental thermal comfort for large-scale, long-term outdoor activities; and (3) provide suggestions for the arrangement of shifts in routes and participants for heat warning and mitigation. Taiwan ReAnalysis Downscaling (TReAD) data, Sky View Factors (SVFs), GSV2SVF tool, and RayMan Pro were applied to analyze and evaluate thermal comfort at the 2021 Torch Relay Round the Island, Taiwan. In this study, modified Physiologically Equivalent Temperature (mPET), Wet Bulb Globe Temperature (WBGT), and Universal Thermal Climate Index (UTCI) were estimated and selected as thermal indicators for the purpose of obtaining a more comprehensive perspective. We also define and present thermal performance with a simple traffic light symbol (green: comfortable/yellow: warm/red: hot) and try to go beyond the concept of heat and visualize it in an easy-to-understand way. Full article
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18 pages, 2562 KiB  
Article
Analysis of Mechanical Durability, Hydrophobicity, Pyrolysis and Combustion Properties of Solid Biofuel Pellets Made from Mildly Torrefied Biomass
by Kanageswari Singara veloo, Anthony Lau and Shahab Sokhansanj
Energies 2025, 18(13), 3464; https://doi.org/10.3390/en18133464 - 1 Jul 2025
Cited by 1 | Viewed by 295
Abstract
The production of solid biofuels from torrefied biomass holds significant potential for renewable energy applications. Durable pellet formation from severely torrefied biomass is hindered by the loss of natural binding properties, yet studies on mild torrefaction that preserves sufficient binding capacity for pellet [...] Read more.
The production of solid biofuels from torrefied biomass holds significant potential for renewable energy applications. Durable pellet formation from severely torrefied biomass is hindered by the loss of natural binding properties, yet studies on mild torrefaction that preserves sufficient binding capacity for pellet production without external binders or changes to die conditions remain scarce. This paper investigated the production of fuel pellets from torrefied biomass without using external binders or adjusting pelletization parameters. Experiments were conducted using a mild torrefaction temperature (230 °C and 250 °C) and shorter residence time (10, 15, and 30 min). The torrefied materials were then subjected to pelletization using a single-pellet press; and the influence of torrefaction on the mechanical durability, hydrophobicity, and fuel characteristics of the pellets was examined. Results indicated that the mass loss ranging from 10 to 20% among the mild torrefaction treatments was less than the typical extent of mass loss due to severe torrefaction. Pellets made from torrefied biomass (torrefied pellets) had improvement in the hydrophobicity (moisture resistance) when compared to pellets made from untreated biomass (untreated pellets). Improved hydrophobicity is important for storage and transportation of pellets that are exposed to humid environmental conditions, as it reduces the risk of pellet degradation and spoilage. Thermogravimetric analysis of the pyrolysis and combustion behaviour of torrefied pellets indicated the improvement of fuel characteristics in terms of a much higher comprehensive pyrolysis index and greater thermal stability compared to untreated pellets, as evidenced by the prolonged burnout time and reduced combustion characteristics index. Residence time had a more significant impact on pellet durability than temperature, but the durability of the torrefied pellets was lower than that of the untreated pellets. Further research is required to explore the feasibility of producing binder-free durable pellets under mild torrefaction conditions. Overall, the study demonstrated that mild torrefaction could enhance the fuel quality and moisture resistance of biomass pellets, offering promising advantages for energy applications, despite some trade-offs in mechanical durability. Full article
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27 pages, 4066 KiB  
Article
Brewers’ Spent Grain from Different Types of Malt: A Comprehensive Evaluation of Appearance, Structure, Chemical Composition, Antimicrobial Activity, and Volatile Emissions
by Aleksander Hejna, Joanna Aniśko-Michalak, Katarzyna Skórczewska, Mateusz Barczewski, Paweł Sulima, Jerzy Andrzej Przyborowski, Hubert Cieśliński and Mariusz Marć
Molecules 2025, 30(13), 2809; https://doi.org/10.3390/molecules30132809 - 30 Jun 2025
Viewed by 372
Abstract
Beer is the third most popular beverage in the world, and its production is distributed uniformly between the biggest continents. Considering the environmental aspects, the utilization of brewing by-products, mainly brewers’ spent grain (BSG), is essential on a global scale. The beer revolution, [...] Read more.
Beer is the third most popular beverage in the world, and its production is distributed uniformly between the biggest continents. Considering the environmental aspects, the utilization of brewing by-products, mainly brewers’ spent grain (BSG), is essential on a global scale. The beer revolution, lasting over a few decades, significantly diversified the beer market in terms of styles, and therefore, also its by-products, which should be characterized appropriately prior to further application. Herein, the presented study investigated the unprecedented number of 22 different variants of brewers’ spent grain, yielded from the production of various beer styles, enabling their proper comparison. A comprehensive by-product characterization revealed an almost linear relationship (Pearson correlation coefficients exceeding 0.9) between the color parameters (L*, a*, browning index) of beer and generated spent grain, enabling a prediction of BSG appearance based on beer color. Applying wheat or rye malts increased the content of extractives by over 40%, reducing cellulose content by as much as 45%. Thermal treatments of malts (kilning or smoking) also reduced extractive content and limited antioxidant activity, often by over 30%. A lack of husk for wheat or rye reduced the crystallinity index of spent grain by 21–41%, while the roasting of barley efficiently decomposed the less stable compounds and maintained the cellulose crystalline structure. All the analyzed BSG samples were characterized by low volatile emissions and very limited antimicrobial activity. Therefore, their harmfulness to human health and the environment is limited, broadening their potential application range. Full article
(This article belongs to the Special Issue Re-Valorization of Waste and Food Co-Products)
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16 pages, 7943 KiB  
Article
Waste Coffee Silver Skin as a Natural Filler in PLA-Based Filaments for Fused Filament Fabrication (FFF) Printing
by Ana C. Machado, Ana F. Costa, Ângela R. Rodrigues, Pedro F. Moreira, Fernando M. Duarte and António J. Pontes
Polymers 2025, 17(13), 1766; https://doi.org/10.3390/polym17131766 - 26 Jun 2025
Viewed by 428
Abstract
In this research, novel biocomposite filaments were developed by incorporating coffee silver skin (CSS) waste into polylactic acid (PLA) for use in Fused Filament Fabrication (FFF) technology. CSS was blended with PLA at concentrations of 0, 5, 10, and 15 wt.% to address [...] Read more.
In this research, novel biocomposite filaments were developed by incorporating coffee silver skin (CSS) waste into polylactic acid (PLA) for use in Fused Filament Fabrication (FFF) technology. CSS was blended with PLA at concentrations of 0, 5, 10, and 15 wt.% to address the waste disposal challenge and produce environmentally friendly composite biofilaments for FFF, supporting circular economic efforts. These filaments have the potential to be used in sustainable prototyping, functional parts, and consumer products. A comprehensive analysis was conducted to examine the effect of printing temperature on dimensional accuracy, melt flow index (MFI), and mechanical properties. Higher printing temperatures and increased CSS content led to larger dimensions due to increased material fluidity, as confirmed by MFI results, which increased from 3.5 g/10 min (0% CSS) to 5.8 g/10 min (15% CSS) at 180 °C, reaching 26.3 g/10 min at 220 °C. Tensile tests on 3D-printed specimens indicated an improvement in elastic modulus with increasing CSS content at lower temperatures (180 °C), rising from 1622 MPa (0% CSS) to 1952 MPa (15% CSS), representing about a 20% increase. However, at higher temperatures, the elastic modulus decreased, possibly due to the poor dispersion and agglomeration of filler particles. Tensile strength generally decreased with CSS addition, especially at higher loadings, while yield elongation remained low (~1.4–1.7%), indicating a more brittle material. The findings also revealed no significant thermal changes with increasing CSS content, and good printability was achieved for all compositions, which was characterized by good layer adhesion, the absence of warping, and the ease of extrusion. Full article
(This article belongs to the Section Polymer Applications)
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18 pages, 3896 KiB  
Article
The Contribution of Meteosat Third Generation–Flexible Combined Imager (MTG-FCI) Observations to the Monitoring of Thermal Volcanic Activity: The Mount Etna (Italy) February–March 2025 Eruption
by Carolina Filizzola, Giuseppe Mazzeo, Francesco Marchese, Carla Pietrapertosa and Nicola Pergola
Remote Sens. 2025, 17(12), 2102; https://doi.org/10.3390/rs17122102 - 19 Jun 2025
Viewed by 511
Abstract
The Flexible Combined Imager (FCI) instrument aboard the Meteosat Third Generation (MTG-I) geostationary satellite, launched in December 2022 and operational since September 2024, by providing shortwave infrared (SWIR), medium infrared (MIR) and thermal infrared (TIR) data, with an image refreshing time of 10 [...] Read more.
The Flexible Combined Imager (FCI) instrument aboard the Meteosat Third Generation (MTG-I) geostationary satellite, launched in December 2022 and operational since September 2024, by providing shortwave infrared (SWIR), medium infrared (MIR) and thermal infrared (TIR) data, with an image refreshing time of 10 min and a spatial resolution ranging between 500 m in the high-resolution (HR) and 1–2 km in the normal-resolution (NR) mode, may represent a very promising instrument for monitoring thermal volcanic activity from space, also in operational contexts. In this work, we assess this potential by investigating the recent Mount Etna (Italy, Sicily) eruption of February–March 2025 through the analysis of daytime and night-time SWIR observations in the NR mode. The time series of a normalized hotspot index retrieved over Mt. Etna indicates that the effusive eruption started on 8 February at 13:40 UTC (14:40 LT), i.e., before information from independent sources. This observation is corroborated by the analysis of the MIR signal performed using an adapted Robust Satellite Technique (RST) approach, also revealing the occurrence of less intense thermal activity over the Mt. Etna area a few hours before (10.50 UTC) the possible start of lava effusion. By analyzing changes in total SWIR radiance (TSR), calculated starting from hot pixels detected using the preliminary NHI algorithm configuration tailored to FCI data, we inferred information about variations in thermal volcanic activity. The results show that the Mt. Etna eruption was particularly intense during 17–19 February, when the radiative power was estimated to be around 1–3 GW from other sensors. These outcomes, which are consistent with Multispectral Instrument (MSI) and Operational Land Imager (OLI) observations at a higher spatial resolution, providing accurate information about areas inundated by the lava, demonstrate that the FCI may provide a relevant contribution to the near-real-time monitoring of Mt. Etna activity. The usage of FCI data, in the HR mode, may further improve the timely identification of high-temperature features in the framework of early warning contexts, devoted to mitigating the social, environmental and economic impacts of effusive eruptions, especially over less monitored volcanic areas. Full article
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37 pages, 8780 KiB  
Article
Sustainable Self-Healing Geopolymer Concrete Incorporating Recycled Plastic, Brick Waste, and Bacillus sphaericus
by Tamer I. Ahmed, Ahmed S. Rashed and Dina E. Tobbala
Ceramics 2025, 8(2), 72; https://doi.org/10.3390/ceramics8020072 - 17 Jun 2025
Cited by 1 | Viewed by 724
Abstract
This research aims to develop self-healing geopolymer concrete (SHG) to address the limitations of conventional repair methods, including reduced thermal conductivity and density, while promoting sustainable construction. The incorporation of the self-healing method (SHM), crushed brick (CB), and minced water bottles (F-PET) resulted [...] Read more.
This research aims to develop self-healing geopolymer concrete (SHG) to address the limitations of conventional repair methods, including reduced thermal conductivity and density, while promoting sustainable construction. The incorporation of the self-healing method (SHM), crushed brick (CB), and minced water bottles (F-PET) resulted in reduced thermal conductivity, maintenance costs, and environmental impact. This study investigated the effects of varying amounts of CB, F-PET, and SHM on several properties, including flowability, setting times, densities, ductility index (DI), and mechanical strengths, across 13 different mixtures. Additionally, water absorption (WA%), residual weight loss (WL%), and relative dynamic modulus of elasticity (RDME%) were assessed following freeze–thaw cycles, alongside SEM analysis and thermal transport measurements of the SHG mixtures. The inclusion of up to 50% CB enhanced density and thermal conductivity but negatively affected other properties. In contrast, incorporating 25% F-PET led to modest improvements in mechanical, thermal, and durability properties; however, it did not reduce density and thermal conductivity as effectively as CB. Among the three mixtures containing both CB and F-PET, the formulation with 37.5% CB and 12.5% F-PET exhibited the lowest density (1650 kg/m3) and thermal conductivity (1.083 W/m·K). The self-healing capacity of SHM was demonstrated through its ability to close cracks, facilitated by the deposition of CaCO3 under combined durability conditions. Incorporating 2%, 3%, and 4% SHM into the 37.5% CB and 12.5% F-PET mixture significantly improved key properties, including strength, water absorption, freeze–thaw resistance, SEM characteristics, density, and thermal conductivity. The addition of 4% SHM enhanced the mechanical performance of the geopolymer concrete (GVC) after 28 days, resulting in increases of 27% in compressive strength, 40.5% in tensile strength, 81% in flexural strength, and 61.6% in ductility index. Further, the inclusion of SHM improved density, reduced WA% and WL%, and enhanced RDME% after 300 freeze–thaw cycles. Specifically, thermal conductivity decreased from 1.8 W/m·K to 0.88 W/m·K, and density reduced from 2480 kg/m3 to 1760 kg/m3. Meanwhile, WA%, WL%, and RDME% improved from 3%, 4.5%, and 45% to 2%, 2.5%, and 50%, respectively. Full article
(This article belongs to the Special Issue The Production Processes and Applications of Geopolymers, 2nd Edition)
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17 pages, 4159 KiB  
Article
Analysis of Regional Differences in Asphalt Binder Under All-Weather Aging Based on Rheological and Chemical Properties
by Meng Guo, Yixiang Dong, Xu Yin, Mingyang Guan, Meichen Liang, Xudong Wang and Xiuli Du
Materials 2025, 18(12), 2829; https://doi.org/10.3390/ma18122829 - 16 Jun 2025
Viewed by 347
Abstract
Asphalt binder aging under natural exposure critically determines pavement durability, though current research inadequately captured performance evolution across diverse regional climates. This study investigated climate-driven degradation mechanisms through 12-month all-weather aging (AWA) tests in Gansu, Shandong, and Beijing via rheological (G-R parameter, [...] Read more.
Asphalt binder aging under natural exposure critically determines pavement durability, though current research inadequately captured performance evolution across diverse regional climates. This study investigated climate-driven degradation mechanisms through 12-month all-weather aging (AWA) tests in Gansu, Shandong, and Beijing via rheological (G-R parameter, stiffness modulus S-value) and chemical analyses (carbonyl index IC=O, sulfoxide index IS=O). The results demonstrated significant region-dependent aging disparities beyond laboratory simulation. In Gansu, extreme thermal fluctuations and UV radiation accelerated hardening via thermal stress cycles and photo-oxidation, yielding 52.4% higher G-R parameter than PAV. In Shandong, humid saline environments triggered sulfur oxidation-driven electrochemical corrosion, increasing IS=O by 4.2% compared to PAV. In Beijing, synergistic UV–thermal oxidation elevated IC=O and S-value by 8% and 40.7%, respectively versus PAV. Critically, IC=O exhibited strong positive correlations with rheological degradation across regions (r > 0.90, p < 0.01). Based on IC=O, the 12-month all-weather aging rate in Beijing exceeded Gansu and Shandong by 18.5% and 68%, revealing UV–thermal coupling as the most severe degradation pattern. Novelty lies in quantifying region-specific multi-factor coupling effects (UV–thermal, hygrothermal–salt, etc.) and demonstrating their superior severity over PAV (Beijing > Gansu > Shandong). Dominant environmental factors showed distinct regional variations: UV radiation and temperature difference dominated in Gansu (IC=O, r = 0.76) and Beijing (0.74), while precipitation—IC=O correlation prevailed in Shandong (0.76), yet multi-factor coupling ultimately governed aging. These findings provide theoretical foundations for region-tailored and climate-resilient asphalt pavement design. Full article
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