Search Results (575)

The applied design of recycled aggregate concrete (RAC) with supplementary cementitious materials (SCMs) requires reliable estimation of 28-day flexural strength (FS28) before trial batching. This is challenging because RAC–SCM mixtures involve nonlinear interactions among binder chemistry, aggregate replacement, water-to-binder ratio, and admixture dosage. However, most predictive models focus on compressive strength or sustainability optimization, while fewer address FS28 using chemically informed descriptors and independent validation. This study developed and externally validated an XGBoost framework for FS28 prediction. The methodology combined binder characterization by XRF, XRD, SEM, and particle-size analysis; reactivity descriptors; database development; modeling; and experimental validation. A database of 397 mixtures from 22 sources was refined to 382 observations for training and testing, and the model was validated with 58 RAC–SCM mixtures and 174 prismatic specimens tested according to ASTM C78/C78M-22. XGBoost achieved R² values of 91.61%, 80.75%, and 77.62% for training, testing, and validation, with RMSE values of 0.559, 0.835, and 0.364 MPa. Compared with the best alternative models, XGBoost reduced RMSE by 8.6% in testing and 9.5% in validation. Interpretability analysis identified binder reactivity, water-to-binder ratio, aggregate composition, cement content, SCM replacement, and superplasticizer dosage as key factors. Full article

To address the inherent conflict between fluidity and stability in high-concentration unclassified tailings slurries for blasthole stemming slurry (BSS), this study establishes an evaluation system based on “equal fluidity” to screen and optimize chemical admixtures suitable for high-concentration BSS. Three typical superplasticizers—polycarboxylate (PCE), naphthalene-based (NF), and melamine-based (MF)—were selected to systematically compare their effects on rheological parameters and bleeding performance under a controlled, consistent fluidity condition (16.0 ± 0.5 cm). The results indicate that the effectiveness of superplasticizers exhibits noticeably concentration dependence. While NF demonstrates the highest dispersion efficiency at low concentrations, PCE emerges as the sole effective admixture capable of maintaining the fluidity of high-concentration BSS (71% solid mass fraction), attributed to its robust steric hindrance effect. Rheological analysis reveals that the PCE-modified BSS exhibits a unique state characterized by “low yield stress and high differential viscosity,” which effectively decouples the contradiction between macroscopic flow and microscopic stability. Furthermore, the synergistic effect of high concentration and PCE constructs a kinetically stable suspension system, achieving “zero bleeding.” This study confirms that PCE is the optimal choice for preparing high-concentration pumpable BSS, providing a theoretical foundation for the design of deep-hole stemming materials in mining engineering. Full article

Traditional research was mostly focused on the effects of emulsions on the mechanical properties and durability of cement mortar, while studies on the regulation mechanism of emulsions on the rheological properties of cement-based materials and the coupling mechanism with the hydration process were rarely conducted. In this paper, a novel core–shell structured emulsion was prepared by free radical polymerization. The regulation of cement mortar yield stress, creep recovery, dynamic viscosity, and thixotropy by different dosages (0–10%) of the emulsion admixture was systematically investigated, and combined with characterization by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR), the microscopic action mechanism of the emulsion was elucidated. It was demonstrated that the Bingham fluid behavior of cement mortar was not altered by the core–shell emulsion, whereas a significant dosage-dependent regulatory effect on its rheological parameters was observed, and a critical regulation interval of 4–6% was identified. At an emulsion dosage of 10%, the yield stress of the mortar was increased by 937.0% compared to that of the control group. At dosages of 2–4%, the static structural stability and construction flowability of the mortar were synergistically optimized, and the weakest thixotropy and the best structural stability were exhibited at an emulsion dosage of 4%. A more pronounced shear-thinning behavior was shown by all modified mortars, and their high-shear flowability was not affected. Microstructural analysis confirmed that no chemical reaction occurred between the emulsion and the cement hydration products. Through the triple effects of “hydration retardation by physical coating, pore filling and densification, and composite network enhancement”, a film was formed on the surface of cement particles by the emulsion, which hindered the diffusion of water and ions, thereby regulating the cement hydration process and microstructural evolution. Full article

The pinewood nematode (PWN, Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle)), first introduced into China in 1982, has since spread rapidly, posing a serious threat to forest resource security and ecological balance. This study aimed to analyze the genetic diversity and genetic structure of PWN in eight geographic populations (60 individuals) of Guizhou Province using single nucleotide polymorphisms (SNPs). Results revealed low genetic diversity (Ho values varied from 0.123 to 0.229; He values ranged between 0.117 and 0.212) across the eight sampled populations, along with low levels of genetic differentiation (pairwise Fst values varied from 0.005 to 0.183) among them. Gene flow was generally high between populations, and no clear geographical clustering was observed based on ADMIXTURE, PCA and phylogenetic analysis. These findings provided a scientific basis for tracking the dispersal and identifying the origins of PWN infestations in China. Full article

The Manila clam (Ruditapes philippinarum) is an economically important bivalve widely cultured in coastal aquaculture systems of China. However, the genome-wide genetic background and germplasm differentiation of geographically distinct populations remain unclear, which constrains germplasm conservation and the development of selective breeding programs. In this study, 50 individuals from five representative coastal populations (QZ, ZZ, ZP, CL, and NH) in China were subjected to whole-genome resequencing, producing 126.67 Gb of clean data and 92,593,087 SNPs after stringent filtering. Genetic diversity analyses showed that nucleotide diversity (π) ranged from 0.2453 to 0.2588, observed heterozygosity (Ho) from 0.1316 to 0.1492, and expected heterozygosity (He) from 0.2303 to 0.2435, with the CL population exhibiting relatively lower diversity. Population differentiation was low to moderate, with pairwise F_ST values ranging from 0.0454 to 0.0557. Principal component analysis, neighbor-joining phylogenetic analysis, and Admixture clustering consistently indicated limited population structure and extensive genetic admixture. TreeMix analysis further revealed directional gene flow among populations. Rapid linkage disequilibrium decay and predominantly positive Tajima’s D values suggested relatively stable demographic histories. Despite low genome-wide differentiation, combined F_ST and nucleotide diversity ratio analyses identified localized selective sweep signals in specific genomic regions. These results provide preliminary genome-wide insights into genetic diversity, population connectivity, and candidate localized differentiation signals in R. philippinarum. Given the low sequencing depth, the findings should be interpreted as population-level observations that require further validation using higher-depth genomic datasets before being applied to germplasm conservation and selective breeding programs. Full article

Partially replacing cement with mine tailings offers a sustainable strategy for solid waste resource utilization. As a cement admixture, the compressive strength of tailings-based cement materials serves as a critical performance indicator. Machine learning (ML) techniques offer high efficiency, cost-effectiveness, and superior predictive accuracy. However, variations in the chemical composition of tailings often introduce uncertainties into model predictions. Consequently, this study developed an integrated approach incorporating chemical composition and activation methods as input parameters. Four optimized ML models were deployed to predict the compressive strength of tailings-based cementitious materials. Multiple metrics were employed to evaluate model performance, which identified the PSO-XGBoost model as the superior predictive architecture. SHAP analysis revealed that mechanical grinding, NaOH concentration, and the proportions of gypsum and tailings were the primary features influencing compressive strength. Experimental validation yielded a low prediction error of 8.7%, confirming the model’s high predictive accuracy. This research establishes a robust framework for predicting the strength of tailings-based cementitious materials, providing a theoretical foundation for solid waste upcycling. Full article

This study investigates the effects and mechanisms of three mineral admixtures—fly ash (FA), silica fume (SF), and metakaolin (MK)—on the fresh, mechanical, and microstructural properties of Yellow River sediment (YRS)-based shotcrete. A comprehensive experimental program was conducted, including setting time determination, workability assessment, and mechanical strength evaluation, complemented by microstructural characterization using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results indicate that the incorporation of FA prolonged initial and final setting times and improved pumpability but reduced build-up thickness and compressive strength; splitting tensile strength at later ages remained comparable to the control. SF shortened the final setting time and reduced flowability but enhanced shootability, layer build-up, and medium- to later-age compressive and tensile strengths, with an optimal dosage of 5%. MK accelerated the final setting time, slightly reduced early-age compressive strength, but improved early-age splitting tensile strength and achieved 28-day compressive strength comparable to the control. Microstructural analyses revealed that FA participates in pozzolanic reactions forming C–(A)–S–H gel, while SF and MK promote the formation of dense C–S–H and carboalumination phases, enhancing matrix densification. Based on performance evaluation, the recommended dosages are FA ≤ 20%, SF ≤ 15%, and MK ≤ 15%. These results establish clear links between macroscopic performance and microstructural evolution, providing experimental guidance for the sustainable development of YRS-based shotcrete. Full article

The Tianbao melon (Cucumis melo subsp. agrestis) is a highly valued regional horticultural crop, yet its sustainable development is severely constrained by a narrow genetic base and widespread varietal admixture in the market. In this study, a panel of 32 Tianbao melon accessions was systematically evaluated by integrating field-based phenotypic assessment with genome-wide single-nucleotide polymorphism (SNP) analysis via whole-genome resequencing. Phenotypic analysis based on ten quantitative traits revealed low overall morphological variability, indicating limited discriminatory power of morphological traits alone. In contrast, 173,497 high-quality SNPs uncovered substantial hidden genetic differentiation, partitioning the accessions into four distinct genotypic groups. Notably, accessions TB-17 and TB-27, though nearly indistinguishable morphologically, exhibited clear genetic divergence in both phylogenetic and principal component analyses. Furthermore, a panel of 20 core SNPs with conserved flanking sequences was selected, generating unique molecular fingerprint profiles for all 32 accessions and achieving high discriminatory resolution (pairwise differences ranging from 10 to 13 SNPs). These findings demonstrate that the integration of phenotypic and genome-wide SNP data provides a robust framework for genetic diversity assessment and DNA fingerprinting in Tianbao melon, offering a scientific basis for cultivar identification, intellectual property protection, and precision breeding to support sustainable development of the regional melon industry. Full article

Due to the tendency of backfill slurry to stagnate within pipelines during transportation, a time-dependent rheological model for basalt fiber-reinforced gangue cemented slurry was developed based on the H-B rheological model and flocculation structure theory to ensure unimpeded slurry flow within pipelines over specified time periods. Experiments were conducted to investigate the time-dependent yield stress evolution of 9 mm fiber-reinforced gangue cemented slurry over time under varying conditions, specifically examining the effects of adding 9 mm fiber-reinforced (accounting for 0.5% of the total mass of the slurry) gangue cemented slurry under varying conditions. Significant effects of mass concentration, sucrose admixture content, and fly ash concentration on the yield stress of the slurry under different standing times were investigated. Research findings indicate that the yield stress of the paste increases with rising mass concentration and also rises with extended standing time. For slurries with mass concentrations ranging from 76% to 82%, the yield stress after 120 min of standing increased by 81.03%, 80%, 82%, and 97.48%, respectively, compared to freshly mixed slurries. The yield stress decreases with increasing sucrose dosage. Below 0.5% sucrose dosage, the rate of yield stress increase with standing time is relatively slow; above 0.5%, the rate increases more rapidly. After 120 min of standing, the yield stress of slurries with a sucrose dosage ranging from 0.25% to 1.00% increased by 48.66%, 54.42%, 32.90%, and 33.70%, respectively, compared to freshly mixed slurry. Yield stress decreased with increasing fly ash content and exhibited an overall steady upward trend with standing time. Based on the fitting surfaces depicting the variation in yield stress in filling materials over time under different influencing factors, fitting expressions were derived. Analysis of variance revealed that the time-dependent behavior of filling materials is primarily influenced by mass concentration, followed by retarder dosage and fly ash proportion. Full article

The spongy moth (Lymantria dispar) is a significant defoliator of broadleaf forests and fruit trees, but its population genetic structure in Central Asia remains poorly defined. We analyzed 153 specimens collected from ten populations across Kazakhstan between 2023 and 2024, using a combination of diagnostic real-time PCR, RAPD genotyping, and mitochondrial COI sequencing. Subspecies identification and Asian introgression were initially assessed with the COI/FS1 TaqMan assay. All samples carried the European mitochondrial type L. dispar dispar, while the nuclear FS1 locus indicated Asian introgression in 92.8% of specimens, including eleven heterozygotes for the Asian allele. RAPD amplification with five polymorphic primers produced 107 variable bands, which we converted into a presence/absence matrix for population genetics analysis. Principal coordinate analysis showed weak but detectable population structure, and Bayesian clustering (STRUCTURE) supported the presence of two primary nuclear clusters. Populations from Ketpentau, Sumbe, Kazachka, Butakovka, and Pavlodar were assigned predominantly to one cluster, whereas most individuals from Almaty, Ile-Alatau, Koksu, North Kazakhstan, and Tekeli were assigned predominantly to the other, with limited admixture in several localities. COI sequences formed a single, minimally differentiated L. dispar clade, with no evidence of distinct mitochondrial lineages. Overall, these findings reveal extensive Asian nuclear introgression in populations retaining European mitochondrial haplotypes, supporting the interpretation of Kazakhstan as part of a broad contact zone within the larger dispar–asiatica gradient. The observed mito-nuclear discordance has important implications for quarantine diagnostics and highlights the need for multilocus molecular assays in regional biosurveillance. Full article

Ancient olives are considered a major resource of gene pool, adapted across ages to ever changing environments. The ancient ‘Mehras’ olive is the only cultivar inscribed on the UNESCO Representative List of the Intangible Cultural Heritage Of Humanity as recognized for its longevity and historical significance. However, detailed genetic and phenotypic analyses are still missing. Nineteen ‘Mehras’ accessions were collected from northern Jordan and subjected to inter-simple sequence repeat (ISSR) marker analysis and to a set of phenotypic parameters (leaf, fruit, and stone). ISSR analysis revealed similarity values ranging between 0.53 and 1.00, indicating moderate to high genetic diversity. Bayesian clustering and dendrogram analyses identified two major genetic clusters with limited admixture, indicating extended clonal propagation in addition to the transport of planting material. Phenotypic parameters revealed tangible variation among accessions, with major influence of fruit and stone traits followed by leaf traits. Strong correlations were observed between key traits, including fruit width and flesh thickness, while an inverse relationship was observed between flesh and stone percentages. Multivariate analysis further revealed clear separation among investigated accessions. The Mantel test showed a moderate correlation between genetic and phenotypic distances. Spatial analysis suggested weak geographic structuring of diversity, indicating exchange of plant material. ‘Mehras’ olive harbors structured genetic and phenotypic diversity influenced mainly by adaptation and traditional cultivation practices. These findings provide a foundation for conservation, breeding, and sustainable utilization of this ancient and culturally significant cultivar. Full article

Food adulteration with melamine represents a serious threat to food safety due to its toxic effects and its ability to falsely elevate protein values measured by nitrogen-based methods. Visual inspection and visible reflectance spectroscopy are unsuitable for identifying low-level adulteration. This study evaluates Fourier Transform Infrared (FTIR) spectroscopy combined with chemometric tools for the identification of melamine in brown rice flour adulterated at 0–2.00% (w/w). Under the tested conditions, no clear FTIR-detectable interactions between melamine and starch or proteins were observed, suggesting that melamine primarily acts as a physical admixture. Characteristic melamine absorption bands were identified at 3466, 3415, 1431, and 810 cm⁻¹. Spectral normalization and second-order derivative processing improved sensitivity and enabled quantitative calibration models. The method achieved a limit of detection of 1408 mg/kg. Although this value is above the regulatory threshold of 2.5 mg/kg, the approach provides a rapid, non-destructive screening tool for identifying highly adulterated samples and prioritizing them for confirmatory chromatographic or mass spectrometric analysis. Overall, FTIR spectroscopy combined with chemometric analysis offers an efficient first-line approach for identification of melamine adulteration in brown rice flour. Full article

The use of waste limestone powder from mining to replace natural sand in concrete improves its mechanical performance and durability, reduces production costs, and benefits the ecological environment. In the initial mix design, limestone powder was substituted for natural sand as fine aggregate at specific ratios under constant total mass, investigating the influence of water-to-binder ratio and limestone powder replacement rate on concrete strength to establish preliminary value ranges for the optimal parameters. The secondary mix design employed Design Expert software 13 to develop a response surface model, analyzing the impact of water-to-binder ratio and limestone powder replacement rate on key mechanical properties like compressive and flexural strength, as well as the durability of the concrete containing limestone powder. Furthermore, Digital Image Correlation (DIC) was utilized to monitor the stress–strain state on the concrete surface, with the resulting strain cloud maps used to characterize crack initiation locations and propagation patterns. Overall, the results indicate that the observed performance evolution was governed by the coupled influence of limestone powder replacement rate and total powder content. Under the present experimental conditions, limestone powder demonstrated potential as a sustainable fine aggregate substitute; however, its intrinsic contribution could not be completely isolated because of the simultaneous variation in powder content. The study further clarifies the coupled influence of limestone powder replacement rate and total powder content, while integrating response surface optimization and DIC analysis method to provide a practical framework for limestone powder concrete design and engineering application. Full article

Polish Konik is a native horse breed from Poland often regarded as living descendants of the extinct Tarpan, which has been crucial to the breed’s conservation status and cultural importance. To evaluate Polish Konik origins, we sequenced 12 whole genomes and compared them with 148 horse genomes, including those of modern breeds, ancient Polish horses, Przewalski horses, and the Tarpan. The ADMIXTURE results showed that Polish Konik is dominated by a single ancestral component, which is also common among ancient Polish samples and several primitive breeds. The PCA places Polish Konik in a compact cluster positioned adjacent to the ancient and primitive samples. Both analyses indicate that Polish Konik share an ancestral component with several ancient and primitive-type horse samples. The NJ analysis indicates more complex origins of the breed and its close relationship with the Dülmener. None of the analyses showed a closer relationship of Polish Konik to the Tarpan than other analyzed breeds. The study demonstrates that while Polish Konik shares similarities with ancient and primitive horse populations, its genetic background is more complex, reflecting contributions from modern breeds. Our results indicate a close relationship with the Dülmener pony and do not provide sufficient evidence for the hypothesis of the direct origin of the Polish Konik from the extinct Tarpan. Full article

Chinese Simmental cattle are a high-quality breed developed through long-term crossbreeding and selection after their introduction into China and have become the main dual-purpose cattle population in the Xinjiang region. To deeply dissect the population structure, characteristics of the population structure, and the genetic basis of the twinning trait, this study focused on Xinjiang Chinese Simmental cattle as the main research subject. It integrated genomic data from global public databases to systematically conduct population structure analysis, genetic relationship analysis, and genome-wide selection signature analysis. Population genetic analysis revealed that the IBS matrix and G matrix indicated that some individuals from different geographical origins exhibited distant genetic relationships; the Xinjiang population showed the fastest LD decay, suggesting abundant genetic diversity; the inbreeding coefficient based on Runs of Homozygosity (ROH) across populations ranged from 0.036 to 0.063; principal component analysis and phylogenetic tree showed that some individuals from different geographical origins had certain genetic interconnections; admixture analysis indicated that K = 5 was the optimal model, with each population exhibiting clear genetic differentiation and admixture characteristics. Furthermore, by combining F_st and θπ analysis (comparing the Xinjiang population with other geographical populations), a total of 89 candidate genes associated with the twinning trait in Xinjiang Chinese Simmental cattle were screened, including CYP19A1, HORMAD1, GRB14, CADM2, CXCR4, and others that have been reported to be closely related to oogenesis and reproductive function. In summary, this study explores genome-wide genetic differences among Simmental cattle populations from different regions, deepens our understanding of their population structures, and offers new candidate genes and molecular markers for high-fecundity breeding in Simmental cattle. Full article