Plastic pollution is a universal problem, and microbial management of plastic waste represents a promising area of biotechnological research. This study investigated the ability of bacterial strains which were isolated from landfill soil to degrade Low-Density Polyethylene (LDPE). Strains obtained via serial dilution were screened for LDPE degradation on Minimal Essential Medium (MEM) with hexadecane. Nine isolates producing clearance zones on hexadecane-supplemented MEM were further tested for biofilm formation on LDPE sheets. High cell surface hydrophobicity isolates (>10%) were selected for detailed biodegradation studies. The C-8 bacterial isolate showed the highest LDPE weight loss (3.57%) and exhibited maximum laccase (0.0219 U/mL) and lipase activity (19 mm) among all bacterial isolates after 30 days. Weight loss was further validated by FTIR and SEM analysis. FTIR analysis revealed that in comparison to control, changes in peak were observed at 719 cm-1 (C-H bending), 875.67 cm-1 (C-C vibrations), 1307.07 cm-1 (C-O stretching), 1464.21 cm-1 (C-H bending), 2000-1650 cm-1 (C-H bending), 2849.85 cm-1 (C-H stretching) in microbial treated LDPE sheets. The treated LDPE also displayed increase in carbonyl index (upto 2.5 to 3 folds), double bond index (1 to 2-fold) and internal double bond index (2 to 2.5-fold) indicating oxidation and chain scission in the LDPE backbone. SEM analysis showed substantial micrometric surface damage on the LDPE film, with visible cracks and grooves. Using 16S rRNA gene sequencing, the C-8, C-11, C-15 and C-19 isolate were identified as Bacillus paramycoides, Micrococcus luteus, Bacillus siamensis and Lysinibacillus capsica, respectively.

In this paper, a comprehensive overview was conducted on machine vision in potato cultivation, harvesting, and storage. Common weeds and diseases encountered during potato cultivation were summarized, and the advantages and disadvantages of various detection methods were compared. Additionally, methods for soil clod separation and tuber damage detection during harvesting were reviewed, along with a comparative analysis of their strengths and weaknesses. Furthermore, the defect grading and sprouting detection methods during storage were discussed. While machine vision technology shows good detection ability in potato cultivation, harvesting, and storage, further research is still needed to enhance the accuracy and adaptability of these methods, ultimately promoting the development of the potato industry.

Crushable porous soils, such as volcanic pumice, are distributed worldwide and cause a variety of engineering problems, such as slope hazards. The mechanical properties of these soils are complicated by their high compressibility due to voids in the particles themselves and changes in the soil gradation due to particle crushing. They are usually classified as problematic soils and discussed separately from ordinary granular soils, and their behaviour is not systematically understood. In this study, isotropic and triaxial compression tests were conducted on artificial pumice in order to determine the relationship between the mechanical properties and the particle crushing of crushable porous granular materials. The results showed that the mechanical behaviour of artificial pumice, representative of such materials, can be explained using a particle crushing index, which is related to the degree of efficient packing. Furthermore, a new critical state surface equation was proposed. It is applicable to crushable porous granular materials and shows the potential for expressing the critical state or isotropic consolidation state of such materials as a single surface in a three-dimensional space consisting of three axes: the stress - void ratio - crushing index. The validity of this new equation was confirmed by applying it to natural pumice from previous research. (c) 2025 Production and hosting by Elsevier B.V. on behalf of The Japanese Geotechnical Society. This is an open access article under the CC BY- NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Carrot (Daucus carota) is an important crop grown in Canada and globally. Fresh market carrots have strict cosmetic requirements to command full value at Grade A and are frequently downgraded for irregular shape, size, or pest damage. Organic farming presents challenges for nutrient management, soil health and pest control, which may be mitigated with cover cropping. A 3-year field experiment was conducted on a commercial organic farm to 1) test the effects of six preceding-year cover crop treatments compared to a weedy fallow control on carrot yield and quality, wireworm damage, reasons for downgrading, and populations of plant parasitic nematodes, and 2) characterize within-farm spatiotemperal variability in production to identify strategies to improve and stabilize economic return. Carrot yield (42-55 Mg ha-1), quality (39-92% Grade A) and market value (183-221 $1000 Canadian dollars ha-1) varied drastically across years, and blocks within years (<= 20% differences), but cover crops had no impact on these metrics. The dominant reasons for downgrading were morphological, affecting 7-74% of carrots each year and varying with cover crop only once, where carrots following buckwheat (Fagopyrum esculentum) had fewer shape flaws. Nematodes had no relationship to cover crop or any carrot metric and wireworms damaged only 2% of carrots across all three years. This study found virtually no effect of cover crop species composition on next year's carrots on this farm, and that the farmer-collaborators can optimize their operation by improving crop establishment across space and time, reducing morphological flaws, and seeking higher value for downgraded produce.

Large area civil engineering projects, such as offshore wind farms, require extensive soil investigations for detailed soil characterisations. Site-wide geotechnical soil units are commonly defined for simplification due to budgetary constraints. Consequently, practitioners rely on a limited number of costly laboratory tests and a set of semi-empirical CPT correlations, predominantly established based on research sands, for deriving sand parameters. A recent publication by the authors highlights some valid concerns about currently often applied idealisation when deriving strength parameters of natural sands and presents some possible pathways to address the limitations with a grading curve parameter (d10+d30). In the current paper, the size of the original laboratory test database is increased to improve the robustness of the methods. In addition, the database is used to also explore the potential of the d10+d30-parameter to improve estimations of drained stiffness parameters. However, since the current database mainly consists of relatively fine sands with varying fines content, a previously published database of much coarser clean sands is applied to investigate the limitations of the presented methods. Finally, a new independent trial database is collected to demonstrate the performance of the new methods for estimating drained strength and stiffness parameters compared with commonly applied industry-acknowledged methods. Even though limitations of the presented methods are identified for coarser clean sands, significantly improved reliability is demonstrated when deriving drained strength and stiffness parameters of relatively fine and slightly silty to very silty siliceous offshore sands.

To assess the mechanical behavior of granular materials in triaxial tests, a mandatory condition is to guarantee a representative elemental volume (REV) sample. This is achieved by limiting the minimum sample size and the coarsest particle in the sample (dmax\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$d_\textrm{max}$$\end{document}). The common geotechnical practice is based on the sample scales H/D and alpha=D/dmax\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha = D/d_\textrm{max}$$\end{document}, where D is the sample diameter and H is its height. While, it is widely accepted that H/D should be between 2 and 2.5, international standards do not agree on the minimum alpha\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha$$\end{document}, and the recommended values vary widely between 5 and 20. Moreover, the impact of particle size distribution on REV is not well understood and is consequently overlooked by most standards. In this paper, we present a study of the effects of alpha\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha$$\end{document} and grading on the critical shear strength of granular materials. We conducted DEM simulations of triaxial tests on samples with values of alpha\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha$$\end{document} ranging from 5 to 20 and grading that varied from mono-size particle assemblies to samples, where the ratio between the coarsest and finest particle was dmax/dmin=4\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$d_\textrm{max}/d_\textrm{min}\ = 4$$\end{document}. The results show that the minimum alpha\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha$$\end{document} required to obtain an REV depends on grading. While, for mono-size particle assemblies REV conditions are obtained for alpha >= 12.5\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha \ \ge 12. 5$$\end{document}, better graded samples behave as REV once alpha >= 8\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha \ \ge \ 8$$\end{document}. A detailed analysis of macro and microscopic parameters reveals that alpha\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha$$\end{document} is not necessarily the most suitable parameter to assess REV scales. We discover that, in our samples, a unique relationship between critical shear strength and the number of grains carrying interparticle forces (Np & lowast;\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$N_p*$$\end{document}) exists independently of grading. In effect, REV can be systematically defined as long as Np & lowast;>= 3000\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$N_p* \ge 3000$$\end{document}. The physical source of this observation is linked to the evolution of contact arrangement and force transmission mechanisms, which evolve according to the number of particles engaged in load bearing.

Research on the evolutionary behavior of the particle breakage processes in coarse-grained soil under the action of train load is of practical significance for subgrade construction and maintenance. However, existing studies have not addressed the prediction of particle size distribution evolution. In this paper, the MTS loading system is used to simulate the dynamic train load effect on coarse-grained soil fillers. The study analyzes the influence of dynamic stress amplitude, loading frequency, and vibration times on both the macro-characteristics and micro-characteristics of particle breakage. The characteristics of particle fragmentation in coarse soil filler under high-speed train load are elucidated. Furthermore, a predictive model for the evolution of particle size distribution curves in relation to particle content and relative particle size is established using the ZHU continuous grading curve equation. This model captures the evolution process of particle breakage characteristics in coarse-grained soil fillers subjected to high-speed train loads. The applicability of this model has been verified. Based on the grading prediction model, an integral expression for the breakage rate index is derived, and the evolution characteristics of particle breakage in coarse-grained soil fillers under the action of train load are analyzed. The results indicate that during filling, the particle breakage mode of coarse-grained soil fillers during filling is primarily characterized by fracture and fragmentation; conversely, under dynamic cyclic loading conditions, it is predominantly characterized by fracture and grinding. The breakage rate aligns with the measured results, suggesting that the breakage rate index established in this study can effectively describe the evolution process of particle breakage in railway subgrade coarse-grained soil. After the reaching one million loading cycles, both deformation and particle breakage degree in coarse-grained soil fillers tend to stabilize. Under the action of dynamic stress amplitudes ranging from 10 to 200 kPa and loading frequencies between 2 and 12 Hz, the particle breakage index stabilizes below 1.1%. These research findings contribute to a deeper understanding of the evolutionary processes affecting engineering characteristics of railway subgrade coarse-grained soils and provide a theoretical as well as experimental foundation for railway subgrade construction and maintenance.

There is substantial evidence that crushable soils (e.g., sands, gravels, rockfills, etc.) undergo particle crushing upon shearing or over creeping. To investigate the evolution of grading and particle crushing of coarse-grained materials, a series of consolidated and drained triaxial shearing and creep tests were conducted on rockfills using a large-scale triaxial apparatus. The test data from the sieve analysis test, both before and after the triaxial tests, were subjected to a comprehensive qualitative and quantitative analysis of the variation of grading or breakage index. Research findings indicate a decrease in the percentage of coarser particles in the particle components of rockfills, accompanied by an increase in the amount of particle crushing upon shearing or over creeping. Furthermore, a series of empirical expressions were proposed through nonlinear fitting of test data to characterize the relationship between the breakage index and two variables (i.e., the normalized plastic work and mean effective stress) under various confining pressures and stress levels upon shearing or over creeping. These findings can provide a scientific basis for the design, construction, and maintenance of rockfill dams or high rockfill embankments in the practical engineering application.

The fabric anisotropy in granular soils is a very important character in soil mechanics that may directly affect many geotechnical engineering properties. The principal objective of this study is to develop an efficient approach for assessing the degree of fabric anisotropy as a function of grading, particles shape and weighting specifications. By assuming cross-anisotropy, the anisotropic shear stiffness values of 1042 implemented tests on 200 various sandy and gravelly soil specimens from 43 different soil types were collected from the literature. Those were combined with their corresponding void ratios, stress conditions, grading parameters, particles shape and weighting attributes to generate a global database of anisotropic shear moduli in terms of testing conditions. The magnitudes of fabric anisotropy ratio were obtained using a well-known empirical equation, and they were plotted against the relevant soil grading and particles information to examine the dependency level of this ratio to the particularities. A series of multiple regression analyses were carried out to develop a global correlation for evaluating fabric anisotropy ratio in granular soils from grading, particles shape and weighting characteristic. The results showed that reliable quantities of fabric anisotropy ratio can be estimated using the surface appearance soil specifications. The findings may serve as an appropriate technique to yield good approximations for fabric and shear stiffness anisotropies using soil grading and particle properties.

The global concern for risk control of organic contaminated sites is becoming more and more prominent. Traditional ex situ remediation techniques are costly and damage the site, seriously destroying the soil structure and ecological functions. Therefore, in situ means of combining material injection and microbial remediation have become a potential pathway for the green, economical, and efficient remediation of contaminated sites. In this work, a 200 m2 test block was selected for the coupled injection of slow-release oxygen materials and microbial agents, and long-term monitoring of groundwater was carried out. The results showed that the slow-release materials could release oxygen for a period of 90 days, which provided an oxidizing environment for microorganisms to rapidly degrade BTEX. For the pre-adapted indigenous degradation bacterial agent test group, the degradation degree of BTEX was up to 98% after 40 days of injection. The results of the application on the field scale proved the feasibility of reinforcing biostimulation for remediation of underground organic contamination through the coupled injection of slow-release oxygen materials and microbial agents. The results provided theoretical and technical support for the in situ remediation of petroleum hydrocarbon-contaminated sites.