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Keywords = initial moisture content

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24 pages, 4424 KiB  
Article
Impact of Temperature Manipulations on Growth Performance, Body Composition, and Selected Genes of Koi Carp (Cyprinus carpio koi)
by Kennedy Emeka Amuneke, Ahmed E. Elshafey, Yuanhao Liu, Jianzhong Gao, Justice Frimpong Amankwah, Bin Wen and Zaizhong Chen
Fishes 2025, 10(3), 95; https://doi.org/10.3390/fishes10030095 - 24 Feb 2025
Viewed by 126
Abstract
Aquatic organisms face substantial challenges from climate change, particularly due to rising water temperatures, which significantly impact their growth and survival. This investigation utilized 960 Koi carp (Cyprinus carpio koi) (Initial Body Weight, 0.304 ± 0.005 g). After a 10-day acclimatization [...] Read more.
Aquatic organisms face substantial challenges from climate change, particularly due to rising water temperatures, which significantly impact their growth and survival. This investigation utilized 960 Koi carp (Cyprinus carpio koi) (Initial Body Weight, 0.304 ± 0.005 g). After a 10-day acclimatization period, the fish were distributed equally across 12 glass aquaria (80 × 40 × 45 cm), with three replicates per treatment. This study encompassed two phases. The first phase (10–60 Days Post-Hatching, dph) involved four temperature regimes: T1 (26 °C), T2 (28 °C), T3 (30 °C), and T4 (26/30 °C daily fluctuation). The second phase (60–120 dph) maintained all groups at 30 °C. Initially, T1 exhibited the best growth performance, indicated by the highest Final Body Weight, Weight Gain, Specific Growth Rate (SGR), and Thermal Growth Coefficient (TGC), along with the highest survival rate. Gene expression analysis revealed that HSP70, HSP90, SOD, BCL-2, and FASN were upregulated in T3 and T4, indicative of stress, while MYOD was highest in T1. During the second phase, T4 displayed superior growth and a healthier body composition with elevated moisture and protein, and reduced fat content compared to T1 and T2. HSP70, HSP90, and BCL-2 expression increased significantly in T1, suggesting thermal stress, whereas MYOD levels rose across all treatments, peaking in T4, which correlated with its growth. Further, there were strong relationships among growth parameters, gene expression, and body composition, with T4 exhibiting the highest essential and non-essential amino acids and a unique fatty acid profile. Overall, the results suggest that manipulated temperature significantly influences Koi carp’s characteristics, making it more adaptable to future environmental stress. Full article
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27 pages, 12791 KiB  
Article
Predicting the Unsaturated Hydraulic Conductivity of Compacted Polyurethane–Clay Using the Filter Paper Method
by Mary Ann Adajar and Cielo Frianeza
Appl. Sci. 2025, 15(5), 2411; https://doi.org/10.3390/app15052411 - 24 Feb 2025
Viewed by 116
Abstract
Sanitary landfill covers are exposed to varying environmental conditions; hence, the state of the clay layer also changes from saturated to unsaturated. The study aimed to predict the unsaturated hydraulic conductivity of the locally available compacted clay and clay with polyurethane to determine [...] Read more.
Sanitary landfill covers are exposed to varying environmental conditions; hence, the state of the clay layer also changes from saturated to unsaturated. The study aimed to predict the unsaturated hydraulic conductivity of the locally available compacted clay and clay with polyurethane to determine their behavior as they change from wet to dry using matric suction and empirical models proposed through other studies. The specimens underwent three wet–dry cycles wherein the matric suction was determined for several moisture content levels as the specimen dried using the filter paper method or ASTM D5298. The results showed that the factors affecting the soil structure, such as grain size difference between clay and polyurethane–clay, varying initial void ratios, and degradation of the soil structure due to the wet–dry cycles, did not affect the matric suction at the higher suction range; however, these factors had an effect at the lower suction range. The matric suction obtained was then used to establish the best fit water retention curve (WRC) or the relationship between the matric suction and moisture content. The WRC was used to predict the unsaturated hydraulic conductivity and observe the soil–water interaction. The study also observed that the predicted unsaturated hydraulic conductivity decreases as the compacted specimen moves to a drier state. Full article
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17 pages, 12216 KiB  
Article
Experimental Study on Infiltration Characteristics of Shallow Rainwater in Expansive Soil Slopes at Different Gradients
by Quan Shen, Yidan Zhang, Yuan Yan, Hongyuan Dong and Wenkai Lei
Water 2025, 17(5), 642; https://doi.org/10.3390/w17050642 - 22 Feb 2025
Viewed by 182
Abstract
Expansive soils are widely distributed in tropical and subtropical regions and are highly sensitive to moisture variations, posing significant challenges to slope stability. Rainfall infiltration alters the hydro-mechanical behavior of expansive soils, increasing the risk of landslides and slope failures. Understanding the infiltration [...] Read more.
Expansive soils are widely distributed in tropical and subtropical regions and are highly sensitive to moisture variations, posing significant challenges to slope stability. Rainfall infiltration alters the hydro-mechanical behavior of expansive soils, increasing the risk of landslides and slope failures. Understanding the infiltration dynamics under different slope conditions is therefore essential for improving slope stability management and disaster mitigation. To investigate the mechanisms governing the long-term stability of steep expansive soil slopes, this study designed and constructed a multi-slope combination model test box. Model experiments were conducted on rainfall-induced expansive soil slopes with varying gradients to analyze the interaction between surface runoff and seepage under different rainfall conditions. The results demonstrate that slope gradient plays a crucial role in the rainfall infiltration process. As the slope gradient decreases, the time required for runoff initiation increases, and rainfall infiltration becomes the dominant process, while runoff plays a secondary role. This effect is more pronounced at lower slope gradients. Furthermore, as the slope gradient increases, the variation in soil moisture content decreases, and the influence of rainfall on deeper soil layers is reduced. Beyond a certain threshold, further increases in slope angle result in a diminished effect on enhancing surface runoff and limiting infiltration. Additionally, steeper slopes exhibit a slower rise in soil moisture content during rainfall events. The results also indicate that as the slope gradient increases, the depth of soil affected by rainfall becomes shallower, and the migration speed of the wetting front decreases. The findings of this study provide valuable insights into slope hydrodynamics and serve as a scientific basis for sustainable slope management and soil conservation in expansive soil regions. Full article
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28 pages, 7937 KiB  
Article
The Effects of Lime and Cement Addition on the Compaction and Shear Strength Parameters of Silty Soils
by Andrzej Gruchot, Katarzyna Kamińska and Agnieszka Woś
Materials 2025, 18(5), 974; https://doi.org/10.3390/ma18050974 - 21 Feb 2025
Viewed by 244
Abstract
This article presents the results of laboratory tests of compaction parameters and shear strength of silty soils with and without the addition of hydraulic binder in the form of lime and/or cement. The tests were carried out on samples formed with an optimum [...] Read more.
This article presents the results of laboratory tests of compaction parameters and shear strength of silty soils with and without the addition of hydraulic binder in the form of lime and/or cement. The tests were carried out on samples formed with an optimum moisture content and with 0, 3, 5, and 8% hydraulic binder added to the dry mass of the soil. The soil samples were examined after 7 and 14 days of air–water treatment without and with freeze–thaw cycles. It was found that the addition of lime and cement caused changes in the compaction parameters. This effect depended to a large extent on the type of binder, and also on the grain size composition of the tested soil. The tests showed that the shear strength and the parameters describing it, i.e., the angle of internal friction and cohesion, were high and largely depended on the type of binder and the sample treatment method, as well as its duration. The obtained results indicate that the use of hydraulic binders was an effective method of surface stabilization. Improving soil properties based on the addition of a hydraulic binder is a beneficial method for the environment from the viewpoint of sustainable development and reducing CO2 emissions because it does not require the use of, e.g., soil replacement. Using the SHAP algorithm, it was found that normal stress, initial moisture content, and curing time of the samples were the main input features that influenced the shear strength. Full article
(This article belongs to the Section Mechanics of Materials)
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18 pages, 4222 KiB  
Article
Vertical Stratification Reduces Microbial Network Complexity and Disrupts Nitrogen Balance in Seasonally Frozen Ground at Qinghai Lake in Tibet
by Ni Zhang, Zhiyun Zhou, Yijun Wang, Shijia Zhou, Jing Ma, Jianqing Sun and Kelong Chen
Microorganisms 2025, 13(2), 459; https://doi.org/10.3390/microorganisms13020459 - 19 Feb 2025
Viewed by 151
Abstract
Global climate change has accelerated the reduction of permafrost regions across different altitude gradients, shortening the duration of the freezing period to varying extents. However, the response of the soil microorganisms of frozen soils along altitude gradients remains unclear. In this study, we [...] Read more.
Global climate change has accelerated the reduction of permafrost regions across different altitude gradients, shortening the duration of the freezing period to varying extents. However, the response of the soil microorganisms of frozen soils along altitude gradients remains unclear. In this study, we employed 16S rRNA sequencing and LC-MS metabolomics to investigate the response of soil microbial communities and soil metabolites to vertical stratification in the permafrost soils of the Qinghai Lake region. The results indicated that Proteobacteria, Firmicutes, and Actinobacteria were key soil bacterial phyla in the permafrost soils of Qinghai Lake during the freezing period, with Proteobacteria and Firmicutes showing significant sensitivity to vertical stratification (p < 0.05). The majority of the physicochemical factors exhibited a trend of initially increasing and then decreasing with increasing altitude, whereas pH showed the opposite trend. pH and moisture content were identified as the most important environmental factors influencing soil bacterial community structure. Deterministic processes dominated the assembly of bacterial communities of frozen soils in the Qinghai Lake basin. Co-occurrence network analysis showed that increasing altitude gradients led to a higher average degree of the bacterial network, while reducing network complexity and inter-species connectivity. Soil metabolomics analysis revealed that vertical stratification altered the metabolic profiles of 27 metabolites, with the significantly changed metabolites primarily associated with carbohydrate and amino acid metabolism. In conclusion, the characteristics of the Qinghai Lake permafrost were regulated by regional vertical stratification, which further influenced microbial community structure and soil metabolic characteristics, thereby altering carbon and nitrogen stocks. Specifically, higher altitudes were more favorable for the retention of the carbon and nitrogen stocks of frozen soils in the Qinghai Lake basin. Full article
(This article belongs to the Collection Feature Papers in Environmental Microbiology)
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14 pages, 2258 KiB  
Article
Self-Sustaining Double-Stage Circularity Through Utilization of Sunflower Agriculture’s Waste in Bio-Fertilizers: Commissioning of a Full-Scale Facility
by Denitza Zgureva-Filipova, Viktoria Nikolova, Lyudmila Krasteva and Kalin Filipov
Appl. Sci. 2025, 15(4), 2203; https://doi.org/10.3390/app15042203 - 19 Feb 2025
Viewed by 172
Abstract
The conception of a circular economy is one of the crucial approaches that could accelerate the processes of achieving sustainable development goals, which challenge all industries and societies. Still, the potential of agricultural waste in this area is not fully covered by technologies. [...] Read more.
The conception of a circular economy is one of the crucial approaches that could accelerate the processes of achieving sustainable development goals, which challenge all industries and societies. Still, the potential of agricultural waste in this area is not fully covered by technologies. This study aims to develop a full-scale technology for self-sustaining double-stage circularity through the utilization of sunflower agriculture’s waste in bio-fertilizers. The investigation is performed in Bulgaria, as available sunflower husk ashes (SHA) are subjected to analyses regarding their applicability for bio-fertilizer production. The design of the technology and full-scale equipment commissioning process are described. The conditions and results from the adjustment tests are presented and, based on these, the optimal operating parameters are defined. The successful granulation of different samples of SHA at these conditions is performed and the final granular bio-fertilizers are characterized with a content of 30 wt. % K2O and 5% wt. P2O. The moisture of the prepared granules is approx. 5 wt. %, and they pass the crushing tests at 2.5 kgf. The biotoxicity of the bio-fertilizer is also analyzed, and the results show its applicability in agriculture. The proposed approach allows the initial sources of K2O and P2O from soil feeding the sunflowers to circulate in different industrial technologies and to reenter the soil through bio-fertilizers. Full article
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17 pages, 2396 KiB  
Article
Exposed Subsoil Under Recovery for 30 Years: Influence of Management Strategies on Soil Physical Attributes and Organic Matter
by Laura Silva Nantes, Carolina dos Santos Batista Bonini, Melissa Alexandre Santos, Lucas da Silva Alves, Josiane Lourencetti, Alfredo Bonini Neto, José Augusto Liberato de Souza, Gabriel Augusto da Silva Lunardelli, Mariana Bonini Silva, Dayara Vivian Alvares and Antonio Paz-Gonzalez
Soil Syst. 2025, 9(1), 17; https://doi.org/10.3390/soilsystems9010017 - 19 Feb 2025
Viewed by 244
Abstract
This study aimed to evaluate the residual effect of different management practices on a subsoil that has been exposed since 1969, which has been under recovery for 30 years. The soil under study is an Oxisol, and its assessment was conducted in 2023 [...] Read more.
This study aimed to evaluate the residual effect of different management practices on a subsoil that has been exposed since 1969, which has been under recovery for 30 years. The soil under study is an Oxisol, and its assessment was conducted in 2023 and 2024. The experiment included nine treatments, with two controls, native vegetation and exposed soil, while the remaining treatments combined green manures (velvet bean, pigeon pea replaced by jack bean), liming, and liming + gypsum application from 1992 to 1997. Starting in 1999, Urochloa decumbens was planted in all plots, and from 2009, native Cerrado tree species naturally emerged. The following parameters were evaluated: gravimetric moisture, aggregate stability, infiltration rate, bulk density, soil penetration resistance, and organic matter content. Soil recovery management techniques reduced soil mechanical penetration resistance by 50% and soil density by 19.47%. The velvet bean increased gravimetric moisture by 11.32% compared to mobilized soil. The exposed soil exhibited an infiltration rate that was 90% lower than the other treatments. Conservation management practices increased the soil organic matter content, particularly in the 0–5 cm layer. Additionally, mucuna increased soil organic matter by 7% in the 10–20 cm layer and enhanced the soil organic carbon content. The strategies involving an initial use of velvet bean, velvet bean + liming, or velvet bean with liming + gypsum positively influenced the soil moisture, bulk density, aggregate stability, and organic matter at the 5–10 cm and 10–20 cm depths. Furthermore, the use of pigeon pea/jack bean with liming + gypsum improved attributes such as moisture, infiltration, and soil bulk density. It was concluded that green manuring enhances the physical properties of soil, with velvet bean or pigeon pea/jack bean combined with liming + gypsum being effective alternatives that are capable of positively impacting soil recovery. Full article
(This article belongs to the Special Issue Research on Soil Management and Conservation: 2nd Edition)
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19 pages, 4936 KiB  
Article
Sustainable Utilization of Dredged Sediments and Water Treatment Sludges as Construction Materials Through Combined Dewatering and Cement Stabilization Techniques
by Supakij Nontananandh, Nattapas Khumsuprom, Thanet Thongdetsri, Apiniti Jotisankasa, Susit Chaiprakaikeow and Shinya Inazumi
Recycling 2025, 10(1), 22; https://doi.org/10.3390/recycling10010022 - 5 Feb 2025
Viewed by 570
Abstract
This study investigates the sustainable use of seabed dredged sediments and water treatment sludges as construction materials using combined dewatering and cement stabilization techniques. Dredged sediments and water treatment sludges, typically considered waste, were evaluated for their suitability in construction through a series [...] Read more.
This study investigates the sustainable use of seabed dredged sediments and water treatment sludges as construction materials using combined dewatering and cement stabilization techniques. Dredged sediments and water treatment sludges, typically considered waste, were evaluated for their suitability in construction through a series of dewatering and stabilization processes. Dewatering significantly reduced the initial moisture content, while cement stabilization improved the mechanical properties, including strength and stiffness. The unconfined compressive strength (UCS), shear modulus, and microstructural changes were evaluated using various analytical techniques, including unconfined compression testing, free–free resonance testing, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The results show a direct correlation between reduced w/c ratios and increased UCS, confirming the potential of treated sludge as a subbase layer for roads and landfill liners. A chemical analysis revealed the formation of calcium silicate hydrate (CSH) and ettringite, which are critical for strength enhancement. This approach not only mitigates the environmental issues associated with sludge disposal but also supports sustainable construction practices by reusing waste materials. This study concludes that cement-stabilized dredged sediments and water treatment sludges provide an environmentally friendly and effective alternative for use in civil engineering projects. Full article
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16 pages, 4125 KiB  
Article
Heat and Mass Transfer in Shrimp Hot-Air Drying: Experimental Evaluation and Numerical Simulation
by Jhony T. Teleken, Suélen M. Amorim, Sarah S. S. Rodrigues, Thailla W. P. de Souza, João P. Ferreira and Bruno A. M. Carciofi
Foods 2025, 14(3), 428; https://doi.org/10.3390/foods14030428 - 28 Jan 2025
Viewed by 666
Abstract
Shrimp is one of the most popular and widely consumed seafood products worldwide. It is highly perishable due to its high moisture content. Thus, dehydration is commonly used to extend its shelf life, mostly via air drying, leading to a temperature increase, moisture [...] Read more.
Shrimp is one of the most popular and widely consumed seafood products worldwide. It is highly perishable due to its high moisture content. Thus, dehydration is commonly used to extend its shelf life, mostly via air drying, leading to a temperature increase, moisture removal, and matrix shrinkage. In this study, a mathematical model was developed to describe the changes in moisture and temperature distribution in shrimp during hot-air drying. The model considered the heat and mass transfer in an irregular-shaped computational domain and was solved using the finite element method. Convective heat and mass transfer coefficients (57.0–62.9 W/m2∙K and 0.007–0.008 m/s, respectively) and the moisture effective diffusion coefficient (6.5 × 10−10–8.5 × 10−10 m2/s) were determined experimentally and numerically. The shrimp temperature and moisture numerical solution were validated using a cabinet dryer with a forced air circulation at 60 and 70 °C. The model predictions demonstrated close agreement with the experimental data (R2 0.95 for all conditions) and revealed three distinct drying stages: initial warming up, constant drying rate, and falling drying rate at the end. Initially, the shrimp temperature increased from 25 °C to around 46 °C and 53 °C for the process at 60 °C and 70 °C. Thus, it presented a constant drying rate, around 0.04 kg/kg min at 60 °C and 0.05 kg/kg min at 70 °C. During this stage, the process is controlled by the heat transferred from the surroundings. Subsequently, the internal resistance to mass transfer becomes the dominant factor, leading to a decrease in the drying rate and an increase in temperatures. A numerical analysis indicated that considering the irregular shape of the shrimp provides more realistic moisture and temperature profiles compared to the simplified finite cylinder geometry. Furthermore, a sensitivity analysis was performed using the validated model to assess the impact of the mass and heat transfer parameters and relative humidity inside the cavity on the drying process. The proposed model accurately described the drying, allowing the further evaluation of the quality and safety aspects and optimizing the process. Full article
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20 pages, 7434 KiB  
Article
Characterizing and Modeling Infiltration and Evaporation Processes in the Shallow Loess Layer: Insight from Field Monitoring Results of a Large Undisturbed Soil Column
by Ye Tan, Fuchu Dai, Zhiqiang Zhao, Cifeng Cheng and Xudong Huang
Water 2025, 17(3), 364; https://doi.org/10.3390/w17030364 - 27 Jan 2025
Viewed by 456
Abstract
Frequent agricultural irrigation events continuously raise the groundwater table on loess platforms, triggering numerous loess landslides and significantly contributing to soil erosion in the Chinese Loess Plateau. The movement of irrigation water within the surficial loess layer is crucial for comprehending the mechanisms [...] Read more.
Frequent agricultural irrigation events continuously raise the groundwater table on loess platforms, triggering numerous loess landslides and significantly contributing to soil erosion in the Chinese Loess Plateau. The movement of irrigation water within the surficial loess layer is crucial for comprehending the mechanisms of moisture penetration into thick layers. To investigate the infiltration and evaporation processes of irrigation water, a large undisturbed soil column with a 60 cm inner diameter and 100 cm height was extracted from the surficial loess layer. An irrigation simulation event was executed on the undisturbed soil column and the ponding infiltration and subsequent evaporation processes were systematically monitored. A ruler placed above the soil column recorded the ponding height during irrigation. Moisture probes and tensiometers were installed at five depths to monitor the temporal variations in volumetric water content (VWC) and matric suction. Additionally, an evaporation gauge and an automatic weighing balance measured the potential and actual evaporation. The results revealed that the initially high infiltration rate rapidly decreased to a stable value slightly below the saturated hydraulic conductivity (Ks). A fitted Mezencev model successfully replicated the ponding infiltration process with a high correlation coefficient of 0.995. The monitored VWC of the surficial 15 cm-thick loess approached a saturated state upon the advancing of the wetting front, while the matric suction sharply decreased from an initial high value of 65 kPa to nearly 0 kPa. The monitored evaporation process of the soil column was divided into an initial constant rate stage and a subsequent decreasing rate stage. During the constant rate stage, the actual evaporation closely matched or slightly exceeded the potential evaporation rate. In the decreasing rate stage, the actual evaporation rate fell below the potential evaporation rate. The critical VWC ranged from 26% to 28%, with the corresponding matric suction recovering to approximately 25 kPa as the evaporation process transitioned between stages. The complete evaporation process was effectively modeled using a fitted Rose model with a high correlation coefficient (R2 = 0.971). These findings provide valuable insights into predicting water infiltration and evaporation capacities in loess layers, thereby enhancing the understanding of water movement within thick loess deposits and the processes driving soil erosion. Full article
(This article belongs to the Special Issue Monitoring and Control of Soil and Water Erosion)
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22 pages, 4845 KiB  
Article
Batch Adsorption of Orange II Dye on a New Green Hydrogel—Study on Working Parameters and Process Enhancement
by Andrei-Ionuț Simion, Cristina-Gabriela Grigoraș and Lidia Favier
Gels 2025, 11(1), 79; https://doi.org/10.3390/gels11010079 - 20 Jan 2025
Viewed by 561
Abstract
A new green hydrogel consisting of cherry stone (CS) powder and sodium alginate (SA) was synthesized through physical crosslinking. The product had a mean diameter of 3.95 mm, a moisture content of 92.28%, a bulk density of 0.58 g/cm3, and a [...] Read more.
A new green hydrogel consisting of cherry stone (CS) powder and sodium alginate (SA) was synthesized through physical crosslinking. The product had a mean diameter of 3.95 mm, a moisture content of 92.28%, a bulk density of 0.58 g/cm3, and a swelling ratio of 45.10%. The analyses of its morphological structure and functional groups by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) showed the successful entrapping of the CS in the SA polymeric matrix. The viability of the prepared hydrogel as adsorbent was tested towards Orange II (OII) anionic dye. The influence of the pH, adsorbent amount, contact time, and initial dye concentration was evaluated. Then, the impact of three accelerating factors (stirring speed, ultrasound exposure duration, and temperature) on the OII retention was investigated. The highest recorded removal efficiency and adsorption capacity were 82.20% and 6.84 mg/g, respectively. The adsorption followed Elovich and pseudo-second-order kinetics, was adequately described by Freundlich and Khan isotherms, and can be defined as spontaneous, endothermic, and random. The experiments confirmed that the obtained hydrogel can be used acceptably for at least two consecutive cycles, sustaining its effectiveness in water decontamination. Full article
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13 pages, 3315 KiB  
Article
A Particularly Dangerous Case of the Bubble Effect in Transformers That Appeared in a Large Mass of Pressboard Heated by Mineral Oil
by Hubert Moranda and Hanna Moscicka-Grzesiak
Energies 2025, 18(2), 380; https://doi.org/10.3390/en18020380 - 17 Jan 2025
Viewed by 484
Abstract
The topic concerns the so-far-unknown mechanism of the bubble effect (b.e.) in a large mass of moist cellulose heated with mineral oil. The well-known b.e. occurs in the Hot Spot area, i.e., in the place where the hot metal of the windings is [...] Read more.
The topic concerns the so-far-unknown mechanism of the bubble effect (b.e.) in a large mass of moist cellulose heated with mineral oil. The well-known b.e. occurs in the Hot Spot area, i.e., in the place where the hot metal of the windings is in contact with the insulation paper. The authors first showed that cyclic heating of a windings model causes the drying of both the insulation paper and pressboard, but the paper dries faster. For this reason, the bubble effect inception temperature can be lower in the pressboard than in the paper. Next, the authors showed that the bubble effect in the pressboard is very intense and causes a sudden and very large increase in pressure in the tank. Moreover, if the tank seal is suddenly damaged because of this, the number and volume of bubbles will increase dramatically. Next, the influence of the mass of cellulose to the mass of oil ratio on the pressure increase dynamics was tested. This experiment showed that the greater the mass of cellulose to the mass of oil, the greater the increase in pressure in the test chamber. The authors also determined that the characteristics of the bubble effect initiation temperature in the pressboard samples, depending on their moisture content, ranged from 2.0 to 4.8%. The experiment showed that the b.e. in the pressboard proceeds in the same way as in paper insulation. The research results showed that, in addition to the well-known b.e. in the winding paper in the Hot Spot area, the b.e. can occur in a large mass of pressboard cellulose, which can be much more dangerous for the transformer. Full article
(This article belongs to the Special Issue Design and Optimization of Power Transformer Diagnostics: 3rd Edition)
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15 pages, 13730 KiB  
Article
Influence of Humidity on FFP Masks with Electret Filter Media Under Real-Life Wearing Conditions
by Daniel Stoll and Sergiy Antonyuk
Atmosphere 2025, 16(1), 62; https://doi.org/10.3390/atmos16010062 - 8 Jan 2025
Viewed by 900
Abstract
Most FFP (Filtering Face Piece) masks are made from nonwoven filter media that are electrostatically charged, resulting in the additional electrostatic capture mechanism of particles. The protective effect of these masks is therefore mainly dependent on the electric field surrounding the charged fibers. [...] Read more.
Most FFP (Filtering Face Piece) masks are made from nonwoven filter media that are electrostatically charged, resulting in the additional electrostatic capture mechanism of particles. The protective effect of these masks is therefore mainly dependent on the electric field surrounding the charged fibers. Upon prolonged wear, the mask becomes saturated with exhaled air, resulting in humidification on the wearer’s side. However, speaking, coughing, or sneezing also generate droplets, which can deposit on the mask from the person wearing it, as well as from other people. In order to investigate this influence on the filtration efficiency and the existing electric field, an experimental study was carried out. To imitate human breathing, a test setup was constructed using a Sheffield Head with different types of masks. This was followed by the cyclical humidification and drying of the masks through simulated breathing. By observing these phases in detail using sample sections, it was possible to continuously record the water content in the samples, the relative humidity, and the pressure drop (breathing resistance). The results demonstrate that moisture has an impact on the filtration efficiency of the electret FFP masks when worn under real-life conditions and that the initial condition can be restored with sufficient drying time. Full article
(This article belongs to the Special Issue Electrostatics of Atmospheric Aerosols (2nd Edition))
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21 pages, 6169 KiB  
Article
Moisture Loss from Cheese During Baking: Influence of Cheese Type, Cheese Mass, and Temperature
by Justyna Tarapata, Ewa Szymańska, Liesbeth van der Meulen, Joost Miltenburg and Thom Huppertz
Foods 2025, 14(2), 165; https://doi.org/10.3390/foods14020165 - 8 Jan 2025
Viewed by 970
Abstract
This study examined how temperature, cheese mass and moisture content impact moisture loss rate in various cheeses during baking. Understanding these factors is essential for determining the browning properties of cheese during baking. Eight cheese types, differing in moisture content, were baked at [...] Read more.
This study examined how temperature, cheese mass and moisture content impact moisture loss rate in various cheeses during baking. Understanding these factors is essential for determining the browning properties of cheese during baking. Eight cheese types, differing in moisture content, were baked at 100–200 °C in a halogen moisture analyzer, and moisture loss over time was recorded. A mixed-effects model analysis showed that temperature had the most significant impact on moisture loss rate (F = 2008.54; p < 0.00001), followed by cheese mass (F = 1973.28; p < 0.00001) and time (F = 278.49; p < 0.00001). Higher temperatures and larger cheese mass accelerated moisture evaporation rate. The moisture content of cheese explained 21.8% of model variation, suggesting that other factors, such as cheese structure, also play a significant role. The cheese baking process involving moisture removal followed by distinct drying stages. Initially, the drying rate increased as the cheese reached the wet bulb temperature; this was followed by a steady rate, and finally, a reduction in dehydration rate as the moisture decreased, limiting further evaporation. Browning, assessed through changes in lightness (L*), was more noticeable at higher temperatures, particularly in Mozzarella and processed Cheddar, after approx. 30% moisture loss in all cheeses. Full article
(This article belongs to the Section Dairy)
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17 pages, 1415 KiB  
Article
A New Approach for the Utilization of Technical Egg Albumen Based on Acid–Thermal Coagulation
by Plamen Saraliev, Desislav Balev, Desislava Vlahova-Vangelova, Nikolay Kolev and Stefan Dragoev
Appl. Sci. 2025, 15(2), 510; https://doi.org/10.3390/app15020510 - 7 Jan 2025
Viewed by 711
Abstract
Technical albumen (TA) is liquid waste from egg processing enterprises and occupies a share of 10–15% of the waste. Proteins have the property at the isoelectric point of weakening their repulsive forces. This property is the basis of a TA recovery method using [...] Read more.
Technical albumen (TA) is liquid waste from egg processing enterprises and occupies a share of 10–15% of the waste. Proteins have the property at the isoelectric point of weakening their repulsive forces. This property is the basis of a TA recovery method using pretreatment to reduce moisture before drying. In this study, we present the results of a TA processing method using two types of citric and phosphoric acids based on thermal–acid coagulation as an alternative to spray drying. By analyzing physicochemical and microbiological indicators, the raw TA and the finished product are described. In this study, the characteristics of raw TA and its final product are presented. TA contains mainly water, fat, and protein, including all essential amino acids, all of the proteins of the egg white, and some of the yolk. Initially, TA is significantly microbiologically contaminated. A better yield was obtained when using citric acid 97.79% instead of phosphoric acid. The final dried egg product from TA has a protein content of 46% and a fat content of 33%. The dried egg products undergo changes in the lipid and protein fraction during storage, but the values remain low TBARS to 4 mg MDA/kg. Microbiological contamination has decreased due to a decrease in water activity to a level that meets the requirements of European legislation for the processing of animal by-products (ABPs) and uses as feed. Full article
(This article belongs to the Section Food Science and Technology)
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