Saved Queries

Cardiorespiratory fitness is a predictor of long-term health, traditionally assessed through structured exercise protocols that require maximal effort and controlled laboratory conditions. These protocols, while clinically validated, are often inaccessible, physically demanding, and unsuitable for unsupervised monitoring. This study proposes a non-invasive, unsupervised alternative—predicting the heart rate a person would reach after completing the step test, using wearable data collected during natural daily activities. Ground truth post-exercise heart rate was obtained through the Queens College Step Test, which is a submaximal protocol widely used in fitness settings. Separately, wearable sensors recorded heart rate (HR), blood oxygen saturation, and motion data during a protocol of lifestyle tasks spanning a range of intensities. Two machine learning models were developed—a Human Activity Recognition (HAR) model that classified daily activities from inertial data with 96.93% accuracy, and a regression model that estimated post step test HR using motion features, physiological trends, and demographic context. The regression model achieved an average root mean squared error (RMSE) of 5.13 beats per minute (bpm) and a mean absolute error (MAE) of 4.37 bpm. These findings demonstrate the potential of test-free methods to estimate standardized test outcomes from daily activity data, offering an accessible pathway to infer cardiorespiratory fitness. Full article

(This article belongs to the Special Issue Wearable Sensors for Human Position, Attitude and Motion Tracking)

►▼ Show Figures

Figure 1

23 pages, 4322 KiB

Open AccessArticle

Fly-Ash-Based Microbial Self-Healing Cement: A Sustainable Solution for Oil Well Integrity

by Lixia Li, Yanjiang Yu, Qianyong Liang, Tianle Liu, Guosheng Jiang, Guokun Yang and Chengxiang Tang

Sustainability 2025, 17(15), 6989; https://doi.org/10.3390/su17156989 (registering DOI) - 1 Aug 2025

Abstract

The cement sheath is critical for ensuring the long-term safety and operational efficiency of oil and gas wells. However, complex geological conditions and operational stresses during production can induce cement sheath deterioration and cracking, leading to reduced zonal isolation, diminished hydrocarbon recovery, and elevated operational expenditures. This study investigates the development of a novel microbial self-healing well cement slurry system, employing fly ash as microbial carriers and sustained-release microcapsules encapsulating calcium sources and nutrients. Systematic evaluations were conducted, encompassing microbial viability, cement slurry rheology, fluid loss control, anti-channeling capability, and the mechanical strength, permeability, and microstructural characteristics of set cement stones. Results demonstrated that fly ash outperformed blast furnace slag and nano-silica as a carrier, exhibiting superior microbial loading capacity and viability. Optimal performance was observed with additions of 3% microorganisms and 3% microcapsules to the cement slurry. Microscopic analysis further revealed effective calcium carbonate precipitation within and around micro-pores, indicating a self-healing mechanism. These findings highlight the significant potential of the proposed system to enhance cement sheath integrity through localized self-healing, offering valuable insights for the development of advanced, durable well-cementing materials tailored for challenging downhole environments. Full article

(This article belongs to the Section Environmental Sustainability and Applications)

►▼ Show Figures

Figure 1

25 pages, 5899 KiB

Open AccessReview

Non-Invasive Medical Imaging in the Evaluation of Composite Scaffolds in Tissue Engineering: Methods, Challenges, and Future Directions

by Samira Farjaminejad, Rosana Farjaminejad, Pedram Sotoudehbagha and Mehdi Razavi

J. Compos. Sci. 2025, 9(8), 400; https://doi.org/10.3390/jcs9080400 (registering DOI) - 1 Aug 2025

Abstract

Tissue-engineered scaffolds, particularly composite scaffolds composed of polymers combined with ceramics, bioactive glasses, or nanomaterials, play a vital role in regenerative medicine by providing structural and biological support for tissue repair. As scaffold designs grow increasingly complex, the need for non-invasive imaging modalities capable of monitoring scaffold integration, degradation, and tissue regeneration in real-time has become critical. This review summarizes current non-invasive imaging techniques used to evaluate tissue-engineered constructs, including optical methods such as near-infrared fluorescence imaging (NIR), optical coherence tomography (OCT), and photoacoustic imaging (PAI); magnetic resonance imaging (MRI); X-ray-based approaches like computed tomography (CT); and ultrasound-based modalities. It discusses the unique advantages and limitations of each modality. Finally, the review identifies major challenges—including limited imaging depth, resolution trade-offs, and regulatory hurdles—and proposes future directions to enhance translational readiness and clinical adoption of imaging-guided tissue engineering (TE). Emerging prospects such as multimodal platforms and artificial intelligence (AI) assisted image analysis hold promise for improving precision, scalability, and clinical relevance in scaffold monitoring. Full article

(This article belongs to the Special Issue Sustainable Biocomposites, 3rd Edition)

►▼ Show Figures

Figure 1

23 pages, 2122 KiB

Open AccessArticle

Climate Change of Near-Surface Temperature in South Africa Based on Weather Station Data, ERA5 Reanalysis, and CMIP6 Models

by Ilya Serykh, Svetlana Krasheninnikova, Tatiana Gorbunova, Roman Gorbunov, Joseph Akpan, Oluyomi Ajayi, Maliga Reddy, Paul Musonge, Felix Mora-Camino and Oludolapo Akanni Olanrewaju

Climate 2025, 13(8), 161; https://doi.org/10.3390/cli13080161 (registering DOI) - 1 Aug 2025

Abstract

This study investigates changes in Near-Surface Air Temperature (NSAT) over the South African region using weather station data, reanalysis products, and Coupled Model Intercomparison Project Phase 6 (CMIP6) model outputs. It is shown that, based on ERA5 reanalysis, the average NSAT increase in the region (45–10° S, 0–50° E) for the period 1940–2023 was 0.11 ± 0.04 °C. Weak multi-decadal changes in NSAT were observed from 1940 to the mid-1970s, followed by a rapid warming trend starting in the mid-1970s. Weather station data generally confirm these results, although they exhibit considerable inter-station variability. An ensemble of 33 CMIP6 models also reproduces these multi-decadal NSAT change characteristics. Specifically, the average model-simulated NSAT values for the region increased by 0.63 ± 0.12 °C between the periods 1940–1969 and 1994–2023. Based on the results of the comparison between weather station observations, reanalysis, and models, we utilize projections of NSAT changes from the analyzed ensemble of 33 CMIP6 models until the end of the 21st century under various Shared Socioeconomic Pathway (SSP) scenarios. These projections indicate that the average NSAT of the South African region will increase between 1994–2023 and 2070–2099 by 0.92 ± 0.36 °C under the SSP1-2.6 scenario, by 1.73 ± 0.44 °C under SSP2-4.5, by 2.52 ± 0.50 °C under SSP3-7.0, and by 3.17 ± 0.68 °C under SSP5-8.5. Between 1994–2023 and 2025–2054, the increase in average NSAT for the studied region, considering inter-model spread, will be 0.49–1.15 °C, depending on the SSP scenario. Furthermore, climate warming in South Africa, both in the next 30 years and by the end of the 21st century, is projected to occur according to all 33 CMIP6 models under all considered SSP scenarios. The main spatial feature of this warming is a more significant increase in NSAT over the landmass of the studied region compared to its surrounding waters, due to the stabilizing role of the ocean. Full article

(This article belongs to the Topic Climate Change Impacts and Adaptation: Interdisciplinary Perspectives, 2nd Edition)

►▼ Show Figures

Figure 1

20 pages, 4980 KiB

Open AccessArticle

Quinoa Protein/Sodium Alginate Complex-Stabilized Pickering Emulsion for Sustained Release of Curcumin and Enhanced Anticancer Activity Against HeLa Cells

by Yiqun Zhu, Jianan Li, Shuhong Liu, Hongli Yang, Fei Lu and Minpeng Zhu

Foods 2025, 14(15), 2705; https://doi.org/10.3390/foods14152705 (registering DOI) - 1 Aug 2025

Abstract

Quinoa protein isolate (QPI) and sodium alginate (SA) have excellent biocompatibility and functional properties, making them promising candidates for food-grade delivery systems. In this study, we developed, for the first time, a QPI/SA complex-stabilized Pickering emulsion for curcumin encapsulation. The coacervation behavior of QPI and SA was investigated from pH 1.6 to 7.5, and the structural and interfacial characteristics of the complexes were analyzed using zeta potential measurements, Fourier-transform infrared spectroscopy, scanning electron microscopy, and contact angle analysis. The results showed that the formation of QPI/SA complexes was primarily driven by electrostatic interactions, hydrogen bonding, and hydrophobic interactions, with enhanced amphiphilicity observed under optimal conditions (QPI/SA = 5:1, pH 5). The QPI/SA-stabilized Pickering emulsions demonstrated excellent emulsification performance and storage stability, maintaining an emulsification index above 90% after 7 d when prepared with 60% oil phase. In vitro digestion studies revealed stage-specific curcumin release, with sustained release in simulated gastric fluid (21.13%) and enhanced release in intestinal fluid (88.21%). Cytotoxicity assays using HeLa cells confirmed the biocompatibility of QPI/SA complexes (≤500 μg/mL), while curcumin-loaded emulsions exhibited dose-dependent anticancer activity. These findings suggest that QPI/SA holds significant potential for applications in functional foods and oral delivery systems. Full article

(This article belongs to the Section Grain)

►▼ Show Figures

Figure 1

17 pages, 9519 KiB

Open AccessArticle

Lead Recovery from Flue Dust by Using Ultrasonic-Enhanced Hydrogen Peroxide Water Washing

by Tian Wang, Yuxi Xie, Phan Duc Lenh, Thiquynhxuan Le and Libo Zhang

Recycling 2025, 10(4), 150; https://doi.org/10.3390/recycling10040150 (registering DOI) - 1 Aug 2025

Abstract

An ultrasonic-enhanced hydrogen peroxide water-washing process was developed to recover lead from raw flue dust (RFD) under neutral conditions. At optimal parameters (40 °C, 30 min, 4 mL H₂O₂, liquid-to-solid ratio 2:1, 240 W ultrasound), the Pb mass fraction in the solid residue increased from 41.68% in the RFD to 68.11%, accompanied by a Pb recovery rate of 97.1%. These values are significantly higher than those obtained under identical conditions without ultrasound (64.07% and 95.93%, respectively). Ultrasound promotes de-agglomeration and generates •OH radicals that accelerate the oxidation of PbSO₃ to insoluble PbSO₄ while concurrently removing impurity cadmium. This research offers a green and efficient alternative to traditional lead recovery methods, fostering sustainable development in the metallurgical industry. Full article

►▼ Show Figures

Figure 1

20 pages, 1266 KiB

Open AccessSystematic Review

A Systematic Review on Contamination of Marine Species by Chromium and Zinc: Effects on Animal Health and Risk to Consumer Health

by Alexandre Mendes Ramos-Filho, Paloma de Almeida Rodrigues, Adriano Teixeira de Oliveira and Carlos Adam Conte-Junior

J. Xenobiot. 2025, 15(4), 121; https://doi.org/10.3390/jox15040121 (registering DOI) - 1 Aug 2025

Abstract

Potentially toxic elements, such as chromium (Cr) and zinc (Zn), play essential roles in humans and animals. However, the harmful effects of excessive exposure to these elements through food remain unknown. In this sense, this study aimed to evaluate the anthropogenic contamination of chromium and zinc in aquatic biota and seafood consumers. Based on the PRISMA protocol, 67 articles were selected for this systematic review. The main results point to a wide distribution of these elements, which have familiar emission sources in the aquatic environment, especially in highly industrialized regions. Significant concentrations of both have been reported in different fish species, which sometimes represent a non-carcinogenic risk to consumer health and a carcinogenic risk related to Cr exposure. New studies should be encouraged to fill gaps, such as the characterization of the toxicity of these essential elements through fish consumption, determination of limit concentrations updated by international regulatory institutions, especially for zinc, studies on the influence of abiotic factors on the toxicity and bioavailability of elements in the environment, and those that evaluate the bioaccessibility of these elements in a simulated digestion system when in high concentrations. Full article

►▼ Show Figures

Figure 1

18 pages, 7271 KiB

Open AccessArticle

ENO1 from Mycoplasma bovis Disrupts Host Glycolysis and Inflammation by Binding ACTB

by Rui-Rui Li, Xiao-Jiao Yu, Jia-Yin Liang, Jin-Liang Sheng, Hui Zhang, Chuang-Fu Chen, Zhong-Chen Ma and Yong Wang

Biomolecules 2025, 15(8), 1107; https://doi.org/10.3390/biom15081107 (registering DOI) - 1 Aug 2025

Abstract

Mycoplasma bovis is an important pathogen that is associated with respiratory diseases, mastitis, and arthritis in cattle, leading to significant economic losses in the global cattle industry. Most notably in this study, we pioneer the discovery that its secreted effector ENO1 (α-enolase) directly targets host cytoskeletal proteins for metabolic–immune regulation. Using an innovative GST pull-down/mass spectrometry approach, we made the seminal discovery of β-actin (ACTB) as the primary host target of ENO1—the first reported bacterial effector–cytoskeleton interaction mediating metabolic reprogramming. ENO1–ACTB binding depends on a hydrogen bond network involving ACTB’s 117Glu and 372Arg residues. This interaction triggers (1) glycolytic activation via Glut1 upregulation, establishing Warburg effect characteristics (lactic acid accumulation/ATP inhibition), and (2) ROS-mediated activation of dual inflammatory axes (HIF-1α/IL-1β and IL-6/TNF-α). This work establishes three groundbreaking concepts: (1) the first evidence of a pathogen effector hijacking host ACTB for metabolic manipulation, (2) a novel ‘glycolysis–ACTB–ROS-inflammation’ axis, and (3) the first demonstration of bacterial proteins coordinating a Warburg effect with cytokine storms. These findings provide new targets for anti-infection therapies against Mycoplasma bovis. Full article

(This article belongs to the Section Biomacromolecules: Proteins, Nucleic Acids and Carbohydrates)

►▼ Show Figures

Figure 1

19 pages, 5704 KiB

Open AccessArticle

Solving the Enigma of the Identity of Laccaria laccata

by Francesco Dovana, Edoardo Scali, Clarissa Lopez Del Visco, Gabriel Moreno, Roberto Para, Bernardo Ernesto Lechner, Matteo Garbelotto and Tom W. May

J. Fungi 2025, 11(8), 575; https://doi.org/10.3390/jof11080575 (registering DOI) - 1 Aug 2025

Abstract

The taxonomy of Laccaria laccata, the type species of the genus Laccaria, has long been ambiguous due to the absence of a reference sequence and the reliance on early, morphology-based descriptions. To resolve this issue, we selected a Code-compliant lectotype for Agaricus laccatus—the basionym of L. laccata—from Schaeffer’s 1762 illustration cited in Fries’ sanctioning work. Given the limitations of this historical material for modern species interpretation, we also designated an epitype based on Singer’s collection C4083 (BAFC) from Femsjö, Sweden, which was previously but not effectively designated as the “lectotype” by Singer. This epitype is supported by detailed morphological descriptions, iconography, and newly generated nrITS, nrLSU, and RPB2 sequences, which have also been newly obtained from additional collections. Phylogenetic analyses consistently place the epitype of L. laccaria within a well-supported clade, herein designated as/Laccaria laccata, which includes sequences previously reported as falling within the “proxima 1 clade”. This integrative approach, combining historical typification with modern molecular and morphological data, stabilizes the nomenclature of L. laccata and provides a robust foundation for future studies of this ecologically and economically important genus of ectomycorrhizal fungi. Full article

(This article belongs to the Special Issue Fungal Diversity in Europe, 3rd Edition)

►▼ Show Figures

Figure 1

8 pages, 890 KiB

Open AccessCommunication

Single-Cell Protein Using an Indigenously Isolated Methanotroph Methylomagnum ishizawai, Using Biogas

by Jyoti A. Mohite, Kajal Pardhi and Monali C. Rahalkar

Microbiol. Res. 2025, 16(8), 171; https://doi.org/10.3390/microbiolres16080171 (registering DOI) - 1 Aug 2025

Abstract

The use of methane as a carbon source for producing bacterial single-cell protein (SCP) has been one of the most interesting developments in recent years. Most of these upcoming industries are using a methanotroph, Methylococcus capsulatus Bath, for SCP production using natural gas as the substrate. In the present study, we have explored the possibility of using an indigenously isolated methanotroph from a rice field in India, Methylomagnum ishizawai strain KRF4, for producing SCP from biogas [derived from cow dung]. The process was eco-friendly, required minimal instruments and chemicals, and was carried out under semi-sterile conditions in a tabletop fish tank. As the name suggests, Methylomagnum is a genus of large methanotrophs, and the strain KRF4 had elliptical to rectangular size and dimensions of ~4–5 µm × 1–2 µm. In static cultures, when biogas and air were supplied in the upper part of the growing tank, the culture grew as a thick pellicle/biofilm that could be easily scooped. The grown culture was mostly pure, from the microscopic observations where the large size of the cells, with rectangular-shaped cells and dark granules, could easily help identify any smaller contaminants. Additionally, the large cell size could be advantageous for separating biomass during downstream processing. The amino acid composition of the lyophilized biomass was analyzed using HPLC, and it was seen that the amino acid composition was comparable to commercial fish meal, soymeal, Pruteen, and the methanotroph-derived SCP-UniProtein^®. The only difference was that a slightly lower percentage of lysine, tryptophan, and methionine was observed in Methylomagnum-derived SCP. Methylomagnum ishizawai could be looked at as an alternative for SCP derived from methane or biogas due to the comparable SCP produced, on the qualitative level. Further intensive research is needed to develop a continuous, sustainable, and economical process to maximize biomass production and downstream processing. Full article

►▼ Show Figures

Figure 1

35 pages, 1049 KiB

Open AccessArticle

Strategic Human Resource Development for Industry 4.0 Readiness: A Sustainable Transformation Framework for Emerging Economies

by Kwanchanok Chumnumporn Vong, Kalaya Udomvitid, Yasushi Ueki, Nuchjarin Intalar, Akkaranan Pongsathornwiwat, Warut Pannakkong, Somrote Komolavanij and Chawalit Jeenanunta

Sustainability 2025, 17(15), 6988; https://doi.org/10.3390/su17156988 (registering DOI) - 1 Aug 2025

Abstract

Industry 4.0 represents a significant transformation in industrial systems through digital integration, presenting both opportunities and challenges for aligning the workforce, especially in emerging economies like Thailand. This study adopts a sequential exploratory mixed-method approach to investigate how strategic human resource development (HRD) contributes to sustainable transformation, defined as the enduring alignment between workforce capabilities and technological advancement. The qualitative phase involved case studies of five Thai manufacturing firms at varying levels of Industry 4.0 adoption, utilizing semi-structured interviews with executives and HR leaders. Thematic findings informed the development of a structured survey, distributed to 144 firms. Partial Least Squares Structural Equation Modeling (PLS SEM) was used to test the hypothesized relationships among business pressures, leadership support, HRD preparedness, and technological readiness. The analysis reveals that business pressures significantly influence leadership and HRD, which in turn facilitate technological readiness. However, business pressures alone do not directly enhance readiness without the support of intermediaries. These results underscore the critical role of integrated HRD and leadership frameworks in enabling sustainable digital transformation. This study contributes to theoretical perspectives by integrating HRD, leadership, and technological readiness, offering practical guidance for firms aiming to navigate the complexities of Industry 4.0. Full article

(This article belongs to the Special Issue Industry 4.0 and Application of Artificial Intelligence System in Operation Management)

►▼ Show Figures

Figure 1

20 pages, 5041 KiB

Open AccessReview

Aquatic Biomass-Based Carbon Dots: A Green Nanostructure for Marine Biosensing Applications

by Ahmed Dawood, Mohsen Ghali, Laura Micheli, Medhat H. Hashem and Clara Piccirillo

Clean Technol. 2025, 7(3), 64; https://doi.org/10.3390/cleantechnol7030064 (registering DOI) - 1 Aug 2025

Abstract

Aquatic biomass—ranging from fish scales and crustacean shells to various algae species—offers an abundant, renewable source for carbon dot (CD) synthesis, aligning with circular economy principles. This review highlights recent studies for valorizing aquatic biomass into high-performance carbon-based nanomaterials—specifically aquatic biomass-based carbon dots (AB-CDs)—briefly summarizing green synthesis approaches (e.g., hydrothermal carbonization, pyrolysis, and microwave-assisted treatments) that minimize environmental impact. Subsequent sections highlight the varied applications of AB-CDs, particularly in biosensing (including the detection of marine biotoxins), environmental monitoring of water pollutants, and drug delivery systems. Physically AB-CDs show unique optical and physicochemical properties—tunable fluorescence, high quantum yields, enhanced sensitivity, selectivity, and surface bio-functionalization—that make them ideal for a wide array of applications. Overall, the discussion underlines the significance of this approach; indeed, transforming aquatic biomass into carbon dots can contribute to sustainable nanotechnology, offering eco-friendly solutions in sensing, environmental monitoring, and therapeutics. Finally, current challenges and future research directions are discussed to give a perspective of the potential of AB-CDs; the final aim is their integration into multifunctional, real-time monitoring and therapeutic systems—for sustainable nanotechnology innovations. Full article

►▼ Show Figures

Graphical abstract

23 pages, 1178 KiB

Open AccessArticle

A Qualitative Analysis and Discussion of a New Model for Optimizing Obesity and Associated Comorbidities

by Mohamed I. Youssef, Robert M. Maina, Duncan K. Gathungu and Amr Radwan

Symmetry 2025, 17(8), 1216; https://doi.org/10.3390/sym17081216 (registering DOI) - 1 Aug 2025

Abstract

This paper addresses the problem of optimizing obesity, which has been a challenging issue in the last decade based on recent data revealed in 2024 by the World Health Organization (WHO). The current work introduces a new mathematical model of the dynamics of weight over time with embedded control parameters to optimize the number of obese, overweight, and comorbidity populations. The mathematical formulation of the model is developed under certain sufficient conditions that guarantee the positivity and boundedness of solutions over time. The model structure exhibits inherent symmetry in population group transitions, particularly around the equilibrium state, which allows the application of analytical tools such as the Routh–Hurwitz and Metzler criteria. Then, the analysis of local and global stability of the obesity-free equilibrium state is discussed based on these criteria. Based on the Pontryagin maximum principle (PMP), the deviation from the obesity-free equilibrium state is controlled. The model’s effectiveness is demonstrated through simulation using the Forward–Backward Sweeping algorithm with parameters derived from recent research in human health. Incorporating symmetry considerations in the model enhances the understanding of system behavior and supports balanced intervention strategies. Results suggest that the model can effectively inform strategies to mitigate obesity prevalence and associated health risks. Full article

(This article belongs to the Special Issue Mathematical Modeling of the Infectious Diseases and Their Controls)

►▼ Show Figures

Figure 1

18 pages, 6409 KiB

Open AccessArticle

MICP-Treated Coral Aggregate and Its Application in Marine Concrete

by Rui Xu, Baiyu Li, Xiaokang Liu, Ben Peng, Guanghua Lu, Changsheng Yue and Lei Zhang

Materials 2025, 18(15), 3619; https://doi.org/10.3390/ma18153619 (registering DOI) - 1 Aug 2025

Abstract

In marine engineering applications, substituting conventional crushed stone coarse aggregates with coral aggregates offers dual advantages: reduced terrestrial quarrying operations and minimized construction material transportation costs. However, the inherent characteristics of coral aggregates—low bulk density, high porosity, and elevated water absorption capacity—adversely influence concrete workability and mechanical performance. To address these limitations, this investigation employed microbial-induced carbonate precipitation (MICP) for aggregate modification. The experimental design systematically evaluated the impacts of substrate concentration (1 mol/L) and mineralization period (14 days) on three critical parameters, mass gain percentage, water absorption reduction, and apparent density enhancement, across distinct particle size fractions (4.75–9.5 mm, 9.5–20 mm) and density classifications. Subsequent application trials assessed the performance of MICP-treated aggregates in marine concrete formulations. Results indicated that under a substrate concentration of 1 mol/L and mineralization period of 14 days, lightweight coral aggregates and coral aggregates within the 4.75–9.5 mm size fraction exhibited favorable modification effects. Specifically, their mass gain rates reached 11.75% and 11.22%, respectively, while their water absorption rates decreased by 32.22% and 34.75%, respectively. Apparent density increased from initial values of 1764 kg/m³ and 1930 kg/m³ to 2050 kg/m³ and 2207 kg/m³. Concrete mixtures incorporating modified aggregates exhibited enhanced workability and strength improvement at all curing ages. The 28-day compressive strengths reached 62.1 MPa (11.69% increment), 46.2 MPa (6.94% increment), and 60.1 MPa (14.91% increment) for the 4.75–9.5 mm, 9.5–20 mm, and continuous grading groups, respectively, compared to untreated counterparts. Full article

(This article belongs to the Section Construction and Building Materials)

►▼ Show Figures

Figure 1

15 pages, 1635 KiB

Open AccessArticle

Modeling the Abrasive Index from Mineralogical and Calorific Properties Using Tree-Based Machine Learning: A Case Study on the KwaZulu-Natal Coalfield

by Mohammad Afrazi, Chia Yu Huat, Moshood Onifade, Manoj Khandelwal, Deji Olatunji Shonuga, Hadi Fattahi and Danial Jahed Armaghani

Mining 2025, 5(3), 48; https://doi.org/10.3390/mining5030048 (registering DOI) - 1 Aug 2025

Abstract

Accurate prediction of the coal abrasive index (AI) is critical for optimizing coal processing efficiency and minimizing equipment wear in industrial applications. This study explores tree-based machine learning models; Random Forest (RF), Gradient Boosting Trees (GBT), and Extreme Gradient Boosting (XGBoost) to predict AI using selected coal properties. A database of 112 coal samples from the KwaZulu-Natal Coalfield in South Africa was used. Initial predictions using all eight input properties revealed suboptimal testing performance (R²: 0.63–0.72), attributed to outliers and noisy data. Feature importance analysis identified calorific value, quartz, ash, and Pyrite as dominant predictors, aligning with their physicochemical roles in abrasiveness. After data cleaning and feature selection, XGBoost achieved superior accuracy (R² = 0.92), outperforming RF (R² = 0.85) and GBT (R² = 0.81). The results highlight XGBoost’s robustness in modeling non-linear relationships between coal properties and AI. This approach offers a cost-effective alternative to traditional laboratory methods, enabling industries to optimize coal selection, reduce maintenance costs, and enhance operational sustainability through data-driven decision-making. Additionally, quartz and Ash content were identified as the most influential parameters on AI using the Cosine Amplitude technique, while calorific value had the least impact among the selected features. Full article

(This article belongs to the Special Issue Mine Automation and New Technologies)

►▼ Show Figures

Figure 1

Show export options Show export options

Select all

Export citation of selected articles as:

Error

Oops... you haven't selected anything for export.

Displaying article 1-50 on page 1 of 2000.

Go to page 1 2 3 4 5

Search Results (492,764)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI