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14 pages, 2230 KiB  
Article
Complete Mitochondrial (mtDNA) Genome Analysis of Economically Significant Fish Cirrhinus cirrhosus in Bangladesh
by Tajmirul Huda, Md. Alamgir Kabir and Md. Golam Rabbane
Int. J. Mol. Sci. 2025, 26(15), 7473; https://doi.org/10.3390/ijms26157473 (registering DOI) - 2 Aug 2025
Abstract
Complete mitochondrial DNA genome annotation of an ecologically and commercially important fish species Cirrhinus cirrhosus was executed with next-generation sequencing (NGS) for nucleotide and phylogenetic analyses. The findings of this study showed that the Cirrhinus cirrhosus mitochondrial genome contained 16,593 bp, including 13 [...] Read more.
Complete mitochondrial DNA genome annotation of an ecologically and commercially important fish species Cirrhinus cirrhosus was executed with next-generation sequencing (NGS) for nucleotide and phylogenetic analyses. The findings of this study showed that the Cirrhinus cirrhosus mitochondrial genome contained 16,593 bp, including 13 protein-coding genes, 2 ribosomal RNA genes, 22 tRNA genes, and a D-loop region. The overall base composition was 32% adenine, 25% thiamine, 16% guanine, and 27% cytosine. This mitochondrial DNA exhibits an AT biasness, with 56% AT content in its genome. Significant fluctuations were identified in the AT and GC skew values of the ND6 gene, indicating that the selection and mutation forces acting on this gene might be different from those acting on other genes. The Ka/Ks ratios of most protein-coding genes were less than 1, indicating very strong natural selection pressure. Phylogenetic analysis of Cirrhinus cirrhosus with Cirrhinus mrigala and Bangana tungting suggested a closer evolutionary relationship among these species, which might have shared a more recent common ancestor. It has been also found that the genera Labeo and Cirrhinus are not monophyletic. Full article
(This article belongs to the Section Molecular Genetics and Genomics)
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30 pages, 866 KiB  
Article
Balancing Profitability and Sustainability in Electric Vehicles Insurance: Underwriting Strategies for Affordable and Premium Models
by Xiaodan Lin, Fenqiang Chen, Haigang Zhuang, Chen-Ying Lee and Chiang-Ku Fan
World Electr. Veh. J. 2025, 16(8), 430; https://doi.org/10.3390/wevj16080430 (registering DOI) - 1 Aug 2025
Abstract
This study aims to develop an optimal underwriting strategy for affordable (H1 and M1) and premium (L1 and M2) electric vehicles (EVs), balancing financial risk and sustainability commitments. The research is motivated by regulatory pressures, risk management needs, and sustainability goals, necessitating an [...] Read more.
This study aims to develop an optimal underwriting strategy for affordable (H1 and M1) and premium (L1 and M2) electric vehicles (EVs), balancing financial risk and sustainability commitments. The research is motivated by regulatory pressures, risk management needs, and sustainability goals, necessitating an adaptation of traditional underwriting models. The study employs a modified Delphi method with industry experts to identify key risk factors, including accident risk, repair costs, battery safety, driver behavior, and PCAF carbon impact. A sensitivity analysis was conducted to examine premium adjustments under different risk scenarios, categorizing EVs into four risk segments: Low-Risk, Low-Carbon (L1); Medium-Risk, Low-Carbon (M1); Medium-Risk, High-Carbon (M2); and High-Risk, High-Carbon (H1). Findings indicate that premium EVs (L1 and M2) exhibit lower volatility in underwriting costs, benefiting from advanced safety features, lower accident rates, and reduced carbon attribution penalties. Conversely, budget EVs (H1 and M1) experience higher premium fluctuations due to greater accident risks, costly repairs, and higher carbon costs under PCAF implementation. The worst-case scenario showed a 14.5% premium increase, while the best-case scenario led to a 10.5% premium reduction. The study recommends prioritizing premium EVs for insurance coverage due to their lower underwriting risks and carbon efficiency. For budget EVs, insurers should implement selective underwriting based on safety features, driver risk profiling, and energy efficiency. Additionally, incentive-based pricing such as telematics discounts, green repair incentives, and low-carbon charging rewards can mitigate financial risks and align with net-zero insurance commitments. This research provides a structured framework for insurers to optimize EV underwriting while ensuring long-term profitability and regulatory compliance. Full article
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24 pages, 769 KiB  
Article
Parental Involvement in Youth Sports: A Phenomenological Analysis of the Coach–Athlete–Parent Relationship
by Kallirroi Ntalachani, Aspasia Dania, Konstantinos Karteroliotis and Nektarios Stavrou
Youth 2025, 5(3), 81; https://doi.org/10.3390/youth5030081 (registering DOI) - 1 Aug 2025
Abstract
Participation in organized sport is widely encouraged for youth development, yet positive outcomes are not guaranteed. Parents play a pivotal role in shaping young athletes’ experiences, requiring emotional support, interpersonal skills, and self-regulation. This study examines the meanings parents attribute to their children’s [...] Read more.
Participation in organized sport is widely encouraged for youth development, yet positive outcomes are not guaranteed. Parents play a pivotal role in shaping young athletes’ experiences, requiring emotional support, interpersonal skills, and self-regulation. This study examines the meanings parents attribute to their children’s sports participation and how young athletes construct their experiences under parental and coaching influences. An interpretive phenomenological methodology involved semi-structured interviews with coaches, focus groups with parents, and open-ended questionnaires to young athletes. Seventeen players (M = 11.2 years, SD = 0.59), nineteen parents (M = 47.6 years, SD = 3.61), and two coaches from the same football club volunteered to participate in the study. Participants were selected through purposive sampling to ensure a homogeneous experience. The findings reveal that parental involvement balances support and pressure, while trust-building between parents and coaches significantly impacts the athletes’ experiences. The evolving role of technology and the importance of social dynamics within teams also emerged as critical factors. Intrinsic motivation, fostering emotional bonding through the sport, and adopting a developmental rather than purely competitive framework were emphasized factors identified as supporting positive youth sport experiences. These findings offer insights into how interconnected relationships among parents, coaches, and athletes influence children’s sports engagement and development. Full article
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23 pages, 4116 KiB  
Article
Taxonomic and Functional Profiling of Bacterial Communities in Leather Biodegradation: Insights into Metabolic Pathways and Diversity
by Manuela Bonilla-Espadas, Marcelo Bertazzo, Irene Lifante-Martinez, Mónica Camacho, Elena Orgilés-Calpena, Francisca Arán-Aís and María-José Bonete
Bacteria 2025, 4(3), 37; https://doi.org/10.3390/bacteria4030037 (registering DOI) - 1 Aug 2025
Abstract
Leather biodegradation is a complex microbial process with increasing relevance for sustainable waste management. In this study, we investigated bacterial communities responsible for the degradation of leather treated with different tanning agents (chrome, Zeolite, Biole®) using high-throughput 16S rRNA gene sequencing [...] Read more.
Leather biodegradation is a complex microbial process with increasing relevance for sustainable waste management. In this study, we investigated bacterial communities responsible for the degradation of leather treated with different tanning agents (chrome, Zeolite, Biole®) using high-throughput 16S rRNA gene sequencing and metatranscriptomic analysis. Proteobacteria, Bacteroidetes, and Patescibacteria emerged as the dominant phyla, while genera such as Acinetobacter, Pseudomonas, and Sphingopyxis were identified as key contributors to enzymatic activity and potential metal resistance. A total of 1302 enzymes were expressed across all the conditions, including 46 proteases, with endopeptidase La, endopeptidase Clp, and methionyl aminopeptidase being the most abundant. Collagen samples exhibited the highest functional diversity and total enzyme expression, whereas chrome-treated samples showed elevated protease activity, indicating selective pressure from heavy metals. Differential enzyme expression patterns were linked to both the microbial identity and tanning chemistry, revealing genus- and treatment-specific enzymatic signatures. These findings deepen our understanding of how tanning agents modulate the microbial structure and function and identify proteases with potential applications in the bioremediation and eco-innovation of leather waste processing. Full article
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15 pages, 2400 KiB  
Article
Robust Prediction of Cardiorespiratory Signals from a Multimodal Physiological System on the Upper Arm
by Kimberly L. Branan, Rachel Kurian, Justin P. McMurray, Madhav Erraguntla, Ricardo Gutierrez-Osuna and Gerard L. Coté
Biosensors 2025, 15(8), 493; https://doi.org/10.3390/bios15080493 (registering DOI) - 1 Aug 2025
Abstract
Many commercial wearable sensor systems typically rely on a single continuous cardiorespiratory sensing modality, photoplethysmography (PPG), which suffers from inherent biases (i.e., differences in skin tone) and noise (e.g., motion and pressure artifacts). In this research, we present a wearable device that provides [...] Read more.
Many commercial wearable sensor systems typically rely on a single continuous cardiorespiratory sensing modality, photoplethysmography (PPG), which suffers from inherent biases (i.e., differences in skin tone) and noise (e.g., motion and pressure artifacts). In this research, we present a wearable device that provides robust estimates of cardiorespiratory variables by combining three physiological signals from the upper arm: multiwavelength PPG, single-sided electrocardiography (SS-ECG), and bioimpedance plethysmography (BioZ), along with an inertial measurement unit (IMU) providing 3-axis accelerometry and gyroscope information. We evaluated the multimodal device on 16 subjects by its ability to estimate heart rate (HR) and breathing rate (BR) in the presence of various static and dynamic noise sources (e.g., skin tone and motion). We proposed a hierarchical approach that considers the subject’s skin tone and signal quality to select the optimal sensing modality for estimating HR and BR. Our results indicate that, when estimating HR, there is a trade-off between accuracy and robustness, with SS-ECG providing the highest accuracy (low mean absolute error; MAE) but low reliability (higher rates of sensor failure), and PPG/BioZ having lower accuracy but higher reliability. When estimating BR, we find that fusing estimates from multiple modalities via ensemble bagged tree regression outperforms single-modality estimates. These results indicate that multimodal approaches to cardiorespiratory monitoring can overcome the accuracy–robustness trade-off that occurs when using single-modality approaches. Full article
(This article belongs to the Special Issue Wearable Biosensors for Health Monitoring)
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19 pages, 1549 KiB  
Article
Divergence in Coding Sequences and Expression Patterns Among the Functional Categories of Secretory Genes Between Two Aphid Species
by Atsbha Gebreslasie Gebrekidan, Yong Zhang and Julian Chen
Biology 2025, 14(8), 964; https://doi.org/10.3390/biology14080964 (registering DOI) - 1 Aug 2025
Abstract
Disparities in the functional classification of secretory genes among aphid taxa may be attributed to variations in coding sequences and gene expression profiles. However, the driving factors that regulate sequence evolution remain unclear. This study aimed to investigate the differences in coding sequences [...] Read more.
Disparities in the functional classification of secretory genes among aphid taxa may be attributed to variations in coding sequences and gene expression profiles. However, the driving factors that regulate sequence evolution remain unclear. This study aimed to investigate the differences in coding sequences and expression patterns of secretory genes between the rose grain aphid (Metopolophium dirhodum) and the pea aphid (Acrythosiphon pisum), with a particular focus on their roles in evolutionary adaptations and functional diversity. The study involved the rearing of aphids, RNA extraction, de novo transcriptome assembly, functional annotation, secretory protein prediction, and comparative analysis of coding sequences and expression patterns across various functional categories using bioinformatics tools. The results revealed that metabolic genes exhibited greater coding sequence divergence, indicating the influence of positive selection. Moreover, significant expression divergence was noted among functional categories, particularly in metabolic and genetic information processing genes, which exhibited higher variability. This study enhances our understanding of the molecular mechanisms that contribute to phenotypic and genetic diversity among aphid species. This study elucidates the relationship between variations in coding sequences and differences in gene expression among functional categories, thereby establishing a foundation for future studies on gene evolution in response to environmental pressures. Full article
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16 pages, 4530 KiB  
Article
A Novel Selective Oxygen Pressure Leaching for Zinc Extraction from Hemimorphite in Acid-Free Solutions
by Tong Wang, Yubo Zeng, Shuang Zhang, Chen Chen, Yang Li, Wenhui Ma and Hongwei Ni
Metals 2025, 15(8), 858; https://doi.org/10.3390/met15080858 (registering DOI) - 31 Jul 2025
Abstract
A novel acid-free oxygen pressure leaching for the extraction of zinc from hemimorphite was proposed in this study. Green vitriol (FeSO4·7H2O), as one of the important industrial by-products, was used as the leaching reagent to separate zinc from silicon [...] Read more.
A novel acid-free oxygen pressure leaching for the extraction of zinc from hemimorphite was proposed in this study. Green vitriol (FeSO4·7H2O), as one of the important industrial by-products, was used as the leaching reagent to separate zinc from silicon and iron. The effect of leaching conditions, including Fe/Zn molar ratio, leaching temperature, pressure, and reaction time, on the leaching efficiency of zinc, Fe, and Si was investigated systematically. The results showed that the molar ratio of Fe/Zn and leaching temperature play a pivotal role in determining the leaching efficiency rate of Zn. Under the optimized leaching conditions (Fe/Zn molar ratio = 6:1, 150 °C, 1.8 × 106 Pa, and leaching time of 2 h), the leaching efficiency of Zn reached 98.80% and the leaching efficiencies of Fe and Si were 0.76% and 16.80%, respectively. In addition, the shrinking core model was established to represent the relationship between the rate control step and the leaching conditions. The leaching process was controlled by chemical reaction and diffusion, and the activation energy of the leaching process is 97.14 kJ/mol. Full article
(This article belongs to the Special Issue Separation, Reduction, and Metal Recovery in Slag Metallurgy)
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27 pages, 565 KiB  
Review
Review of the Use of Waste Materials in Rigid Airport Pavements: Opportunities, Benefits and Implementation
by Loretta Newton-Hoare, Sean Jamieson and Greg White
Sustainability 2025, 17(15), 6959; https://doi.org/10.3390/su17156959 (registering DOI) - 31 Jul 2025
Viewed by 27
Abstract
The aviation industry is under increasing pressure to reduce its environmental impact while maintaining safety and performance standards. One promising area for improvement lies in the use of sustainable materials in airport infrastructure. One of the issues preventing uptake of emerging sustainable technologies [...] Read more.
The aviation industry is under increasing pressure to reduce its environmental impact while maintaining safety and performance standards. One promising area for improvement lies in the use of sustainable materials in airport infrastructure. One of the issues preventing uptake of emerging sustainable technologies is the lack of guidance relating to the opportunities, potential benefits, associated risks and an implementation plan specific to airport pavements. This research reviewed opportunities to incorporate waste materials into rigid airport pavements, focusing on concrete base slabs. Commonly used supplementary cementitious materials (SCMs), such as fly ash and ground granulated blast furnace slag (GGBFS) were considered, as well as recycled aggregates, including recycled concrete aggregate (RCA), recycled crushed glass (RCG), and blast furnace slag (BFS). Environmental Product Declarations (EPDs) were also used to quantify the potential for environmental benefit associated with various concrete mixtures, with findings showing 23% to 50% reductions in embodied carbon are possible for selected theoretical concrete mixtures that incorporate waste materials. With considered evaluation and structured implementation, the integration of waste materials into rigid airport pavements offers a practical and effective route to improve environmental outcomes in aviation infrastructure. It was concluded that a Triple Bottom Line (TBL) framework—assessing financial, environmental, and social factors—guides material selection and can support sustainable decision-making, as does performance-based specifications that enable sustainable technologies to be incorporated into airport pavement. The study also proposed a consequence-based implementation hierarchy to facilitate responsible adoption of waste materials in airside pavements. The outcomes of this review will assist airport managers and pavement designers to implement practical changes to achieve more sustainable rigid airport pavements in the future. Full article
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16 pages, 738 KiB  
Review
A Rationale for the Use of Ivabradine in the Perioperative Phase of Cardiac Surgery: A Review
by Christos E. Ballas, Christos S. Katsouras, Konstantinos C. Siaravas, Ioannis Tzourtzos, Amalia I. Moula and Christos Alexiou
J. Cardiovasc. Dev. Dis. 2025, 12(8), 294; https://doi.org/10.3390/jcdd12080294 (registering DOI) - 31 Jul 2025
Viewed by 45
Abstract
This review explores the advantages of ivabradine in the management of cardiac surgery patients, particularly highlighting its heart rate (HR)-reducing properties, its role in minimizing the impact of atrial fibrillation, and its contributions to improving left ventricular diastolic function, as well as reducing [...] Read more.
This review explores the advantages of ivabradine in the management of cardiac surgery patients, particularly highlighting its heart rate (HR)-reducing properties, its role in minimizing the impact of atrial fibrillation, and its contributions to improving left ventricular diastolic function, as well as reducing pain, stress, and anxiety. In parallel, studies provide evidence that ivabradine influences endothelial inflammatory responses through mechanisms such as biomechanical modulation. Unlike traditional beta-blockers that may induce hypotension, ivabradine selectively inhibits hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, allowing for effective HR reduction without compromising blood pressure stability. This characteristic is particularly beneficial for patients at risk of atrial fibrillation post-surgery, where HR control is crucial for cardiovascular stability. This is an area in which ivabradine appears to play a role prophylactically, possibly in combination with beta-blockers. Furthermore, ivabradine has been associated with enhanced diastolic parameters in left ventricular function, reflecting its potential to improve surgical outcomes in patients with compromised heart function. In addition to its cardiovascular benefits, it appears to alleviate psychological stress and anxiety, common in postoperative settings, by moderating the neuroendocrine response to stress, thereby reducing stress-induced hormone levels. Furthermore, it has notable analgesic properties, contributing to pain management through its action on HCN channels in both the peripheral and central nervous systems. Collectively, these findings indicate that ivabradine may serve as a valuable therapeutic agent in the perioperative care of cardiac surgery patients, addressing both physiological and psychological challenges during recovery. Full article
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18 pages, 5712 KiB  
Article
A Fractional Fourier Transform-Based Channel Estimation and Equalization Algorithm for Mud Pulse Telemetry
by Jingchen Zhang, Zitong Sha, Lei Wan, Yishan Su, Jiang Zhu and Fengzhong Qu
J. Mar. Sci. Eng. 2025, 13(8), 1468; https://doi.org/10.3390/jmse13081468 - 31 Jul 2025
Viewed by 131
Abstract
Mud pulse telemetry (MPT) systems are a promising approach to transmitting downhole data to the ground. During transmission, the amplitudes of pressure waves decay exponentially with distance, and the channel is often frequency-selective due to reflection and multipath effect. To address these issues, [...] Read more.
Mud pulse telemetry (MPT) systems are a promising approach to transmitting downhole data to the ground. During transmission, the amplitudes of pressure waves decay exponentially with distance, and the channel is often frequency-selective due to reflection and multipath effect. To address these issues, this work proposes a fractional Fourier transform (FrFT)-based channel estimation and equalization method. Leveraging the energy aggregation of linear frequency-modulated signals in the fractional Fourier domain, the time delay and attenuation parameters of the multipath channel can be estimated accurately. Furthermore, a fractional Fourier domain equalizer is proposed to pre-filter the frequency-selective fading channel using fractionally spaced decision feedback equalization. The effectiveness of the proposed method is evaluated through a simulation analysis and field experiments. The simulation results demonstrate that this method can significantly reduce multipath effects, effectively control the impact of noise, and facilitate subsequent demodulation. The field experiment results indicate that the demodulation of real data achieves advanced data rate communication (over 12 bit/s) and a low bit error rate (below 0.5%), which meets engineering requirements in a 3000 m drilling system. Full article
(This article belongs to the Section Ocean Engineering)
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30 pages, 3319 KiB  
Article
A Pilot Study on Thermal Comfort in Young Adults: Context-Aware Classification Using Machine Learning and Multimodal Sensors
by Bibars Amangeldy, Timur Imankulov, Nurdaulet Tasmurzayev, Serik Aibagarov, Nurtugan Azatbekuly, Gulmira Dikhanbayeva and Aksultan Mukhanbet
Buildings 2025, 15(15), 2694; https://doi.org/10.3390/buildings15152694 - 30 Jul 2025
Viewed by 218
Abstract
While personal thermal comfort is critical for well-being and productivity, it is often overlooked by traditional building management systems that rely on uniform settings. Modern data-driven approaches often fail to capture the complex interactions between various data streams. This pilot study introduces a [...] Read more.
While personal thermal comfort is critical for well-being and productivity, it is often overlooked by traditional building management systems that rely on uniform settings. Modern data-driven approaches often fail to capture the complex interactions between various data streams. This pilot study introduces a high-accuracy, interpretable framework for thermal comfort classification, designed to identify the most significant predictors from a comprehensive suite of environmental, physiological, and anthropometric data in a controlled group of young adults. Initially, an XGBoost model using the full 24-feature dataset achieved the best performance at 91% accuracy. However, after using SHAP analysis to identify and select the most influential features, the performance of our ensemble models improved significantly; notably, a Random Forest model’s accuracy rose from 90% to 94%. Our analysis confirmed that for this homogeneous cohort, environmental parameters—specifically temperature, humidity, and CO2—were the dominant predictors of thermal comfort. The primary strength of this methodology lies in its ability to create a transparent pipeline that objectively identifies the most critical comfort drivers for a given population, forming a crucial evidence base for model design. The analysis also revealed that the predictive value of heart rate variability (HRV) diminished when richer physiological data, such as diastolic blood pressure, were included. For final validation, the optimized Random Forest model, using only the top 10 features, was tested on a hold-out set of 100 samples, achieving a final accuracy of 95% and an F1-score of 0.939, with all misclassifications occurring only between adjacent comfort levels. These findings establish a validated methodology for creating effective, context-aware comfort models that can be embedded into intelligent building management systems. Such adaptive systems enable a shift from static climate control to dynamic, user-centric environments, laying the critical groundwork for future personalized systems while enhancing occupant well-being and offering significant energy savings. Full article
(This article belongs to the Section Building Energy, Physics, Environment, and Systems)
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22 pages, 15066 KiB  
Article
Influence of Shot Peening on Selected Properties of the Surface and Subsurface Regions of Additively Manufactured 316L and AlSi10Mg
by Ali Al-Zuhairi, Patrick Lehner, Bastian Blinn, Marek Smaga, Jonas Flatter, Tilmann Beck and Roman Teutsch
Metals 2025, 15(8), 856; https://doi.org/10.3390/met15080856 - 30 Jul 2025
Viewed by 100
Abstract
Due to the high potential of shot peening to improve the surface quality of additively manufactured components, in this work, the influence on surface morphology and, thus, the surface topography and selected properties of the surface and subsurface regions of additively manufactured parts [...] Read more.
Due to the high potential of shot peening to improve the surface quality of additively manufactured components, in this work, the influence on surface morphology and, thus, the surface topography and selected properties of the surface and subsurface regions of additively manufactured parts is analysed. For this, cubic specimens made of stainless steel 316L and AlSi10Mg were manufactured via powder bed fusion laser beam metal (PBF-LB/M), and subsequently, their “as-built” surfaces were shot peened. Shot peening was conducted with stainless steel or ceramic beads using pressures of 3 and 5 bar. The resulting morphologies were analysed regarding topography, microstructure and mechanical properties (hardness and cyclic deformation behaviour) in the subsurface region and the residual stresses. The results demonstrate a strong plastic deformation due to shot peening, resulting in a decreased surface roughness as well as an increased hardness and compressive residual stresses near the surface. These effects were generally more pronounced after using higher peening pressure and/or ceramic beads. Note that two sets of PBF-LB/M parameters were used to produce the AlSi10Mg specimens. The investigation of these specimens reveals an interrelation between the parameters used in shot peening and PBF-LB/M on the resulting surface morphology. Full article
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13 pages, 8060 KiB  
Article
Microstructural, Mechanical, and Thermal Properties of Textured Si3N4/BN Composite Ceramics Prepared Using Two-Step Sintering
by Dexiang Gong, Yi Zhou, Yunwei Shi and Qianglong He
Materials 2025, 18(15), 3573; https://doi.org/10.3390/ma18153573 - 30 Jul 2025
Viewed by 152
Abstract
Textured Si3N4/BN composite ceramics were successfully fabricated using two-step sintering, combining pseudo-hot isostatic pressing (PHIP) and gas pressure sintering. The grain size of h-BN platelets had a significant influence on densification and mechanical and thermal properties. With an increase [...] Read more.
Textured Si3N4/BN composite ceramics were successfully fabricated using two-step sintering, combining pseudo-hot isostatic pressing (PHIP) and gas pressure sintering. The grain size of h-BN platelets had a significant influence on densification and mechanical and thermal properties. With an increase in h-BN grain size, the volume density of the composite ceramics gradually decreased, while flexural strength gradually increased. Meanwhile, larger h-BN platelets were more likely to trigger toughening mechanisms like large-angle deflection and greatly increase fracture toughness. Through proper selection of h-BN grain size, textured ceramics, with the addition of h-BN platelets of 1–2 μm, showed high thermal conductivity (∼92 W∙m−1∙K−1) and reliable mechanical properties (∼540 MPa, ∼7.5 MPa∙m1/2, ∼11.1 GPa). Therefore, texture control is an effective means of improving the overall performance of ceramic materials. Novel textured composite ceramics thus have great potential in large-scale fabrication and directional heat dissipation applications. Full article
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23 pages, 3019 KiB  
Review
Phase-Transfer Catalysis for Fuel Desulfurization
by Xun Zhang and Rui Wang
Catalysts 2025, 15(8), 724; https://doi.org/10.3390/catal15080724 - 30 Jul 2025
Viewed by 109
Abstract
This review surveys recent advances and emerging prospects in phase-transfer catalysis (PTC) for fuel desulfurization. In response to increasingly stringent environmental regulations, the removal of sulfur from transportation fuels has become imperative for curbing SOx emissions. Conventional hydrodesulfurization (HDS) operates under severe [...] Read more.
This review surveys recent advances and emerging prospects in phase-transfer catalysis (PTC) for fuel desulfurization. In response to increasingly stringent environmental regulations, the removal of sulfur from transportation fuels has become imperative for curbing SOx emissions. Conventional hydrodesulfurization (HDS) operates under severe temperature–pressure conditions and displays limited efficacy toward sterically hindered thiophenic compounds, motivating the exploration of non-hydrogen routes such as oxidative desulfurization (ODS). Within ODS, PTC offers distinctive benefits by shuttling reactants across immiscible phases, thereby enhancing reaction rates and selectivity. In particular, PTC enables efficient migration of organosulfur substrates from the hydrocarbon matrix into an aqueous phase where they are oxidized and subsequently extracted. The review first summarizes the deployment of classic PTC systems—quaternary ammonium salts, crown ethers, and related agents—in ODS operations and then delineates the underlying phase-transfer mechanisms, encompassing reaction-controlled, thermally triggered, photo-responsive, and pH-sensitive cycles. Attention is next directed to a new generation of catalysts, including quaternary-ammonium polyoxometalates, imidazolium-substituted polyoxometalates, and ionic-liquid-based hybrids. Their tailored architectures, catalytic performance, and mechanistic attributes are analyzed comprehensively. By incorporating multifunctional supports or rational structural modifications, these systems deliver superior desulfurization efficiency, product selectivity, and recyclability. Despite such progress, commercial deployment is hindered by the following outstanding issues: long-term catalyst durability, continuous-flow reactor design, and full life-cycle cost optimization. Future research should, therefore, focus on elucidating structure–performance relationships, translating batch protocols into robust continuous processes, and performing rigorous environmental and techno-economic assessments to accelerate the industrial adoption of PTC-enabled desulfurization. Full article
(This article belongs to the Special Issue Advanced Catalysis for Energy and a Sustainable Environment)
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16 pages, 2260 KiB  
Article
From Shale to Value: Dual Oxidative Route for Kukersite Conversion
by Kristiina Kaldas, Kati Muldma, Aia Simm, Birgit Mets, Tiina Kontson, Estelle Silm, Mariliis Kimm, Villem Ödner Koern, Jaan Mihkel Uustalu and Margus Lopp
Processes 2025, 13(8), 2421; https://doi.org/10.3390/pr13082421 - 30 Jul 2025
Viewed by 183
Abstract
The increasing need for sustainable valorization of fossil-based and waste-derived materials has gained interest in converting complex organic matrices such as kerogen into valuable chemicals. This study explores a two-step oxidative strategy to decompose and valorize kerogen-rich oil shale, aiming to develop a [...] Read more.
The increasing need for sustainable valorization of fossil-based and waste-derived materials has gained interest in converting complex organic matrices such as kerogen into valuable chemicals. This study explores a two-step oxidative strategy to decompose and valorize kerogen-rich oil shale, aiming to develop a locally based source of aliphatic dicarboxylic acids (DCAs). The method combines air oxidation with subsequent nitric acid treatment to enable selective breakdown of the organic structure under milder conditions. Air oxidation was conducted at 165–175 °C using 1% KOH as an alkaline promoter and 40 bar oxygen pressure (or alternatively 185 °C at 30 bar), targeting 30–40% carbon conversion. The resulting material was then subjected to nitric acid oxidation using an 8% HNO3 solution. This approach yielded up to 23% DCAs, with pre-oxidation allowing a twofold reduction in acid dosage while maintaining efficiency. However, two-step oxidation was still accompanied by substantial degradation of the structure, resulting in elevated CO2 formation, highlighting the need to balance conversion and carbon retention. The process offers a possible route for transforming solid fossil residues into useful chemical precursors and supports the advancement of regionally sourced, sustainable DCA production from unconventional raw materials. Full article
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