Degree Of Degradation Research Articles

Accelerated mineralization of textile wastewater under 222 nm irradiation from Kr/Cl2 excilamp: an environmentally friendly and energy efficient approach

The textile dyeing and manufacturing industry is the major producer of significant amounts of wastewater that contain persistent substances such as azo dyes that require adequate remediation measures. Far ultraviolet at 222 nm light may provide an advantage for contaminants degradation as compared to conventional UV sources (254 nm). In this paper, the degradation of reactive black 5 (RB5) in artificial wastewater has been performed using a 222 nm Kr/Cl2 excimer source under direct photolysis and an advanced oxidation process using TiO2/H2O2. The solution pH, catalyst concentration, 222 nm intensity, initial concentration of dye, and addition of H2O2 influence the degradation rate constant. The molar absorption coefficient, quantum yield of RB5 at 222 nm and the electrical energy per order (EEO) from different treatment methods have been reported. RB5 shows 1.26 times higher molar absorption at 222 nm than at 254 nm. The EEO for excimer-222/H2O2 (∼\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sim$$\\end{document} 13 kWh/m3) is five times lower than that of the excimer-222/TiO2 process, which makes the process energy efficient. The degradation of wastewater has been carried out at three distinct pH values (2, 6, and 10), and the pH level of 10 exhibited the highest degree of degradation. The degradation rate in the alkaline medium is 8.27 and 2.05 times higher than in the acidic or ambient medium. Since textile effluent is highly alkaline, this result is significant, as no neutralization of the wastewater is required, and direct treatment is possible. A possible degradation pathway has been established based on Fourier transform infrared spectroscopy (FTIR) and high resolution mass spectroscopy (HRMS) analysis. The phytotoxicity of the treated wastewater has also been evaluated for its suitability for reuse in agriculture. The study reveals that the excimer-222/H2O2 treated wastewater significantly enhanced the germination percentage of Raphanus sativus seed (97%) compared to dye wastewater-grown seeds (75%). This work offers crucial information for future studies on the direct and indirect photolysis of azo dyes, as well as insight into the process of RB5 degradation under Kr/Cl2 excimer radiation.

Carbon surplus or carbon deficit under land use transformation in China?

With the progression of industrialization and urbanization, terrestrial ecosystems have experienced varying degrees of degradation in their carbon sequestration capabilities, leading to functional loss in some regions. Consequently, the issue of reducing emissions and enhancing carbon sinks, especially in addressing the carbon imbalance brought on by urban and industrial developments, has become a focal point for international organizations and the academic community. Existing studies have separately investigated the effects of changes in single land use types, such as built-up land, forest land, and cropland, on carbon emissions or carbon sequestration. However, few studies have discussed carbon emissions and carbon sequestration within the same framework. This study, based on remote sensing data from 2000 to 2020, utilizes spatial autocorrelation analysis and spatial Durbin model to reveal the long-term trends in land use intensity and carbon balance in China. It was found that the carbon balance index decreased annually by 3.42%, from 0.2406 to 0.0760 during that period. In particular, the eastern and central regions of China exhibited increasingly evident carbon deficits, with most areas along the southeastern coast transitioning from a carbon surplus to a carbon deficit. Over two decades, China’s land use intensity and carbon balance developed a stronger negative spatial dependence. The spatial match and mismatch between land use intensity and carbon deficit are the primary clustering types for their spatial correlation. Each unit increase in land use intensity decreased the local city carbon balance by 0.755 but raised the carbon balance in adjacent areas by 2.740. This indicates that land use intensity impacts the local carbon balance negatively but benefits neighboring regions. There is also evident spatial inequality in different economic zones, with the strongest impact in the Northeast, followed by the Western, Eastern, and Central regions. The resolution of these issues reveals the spatial inequalities and remote driving effects of land use transformation on carbon balance across different scales, from the “entire region” to “economic divisions”. The results of this study provide theoretical and empirical evidence for emissions reduction and carbon sequestration in cities at different levels of land use intensity.

Effect of silicon dioxide nanoparticles on the rheology properties of fresh and mechanically degraded hydrolyzed polyacrylamide polymer solutions

AbstractPartially hydrolyzed polyacrylamide is extensively utilized in enhanced oil recovery operations. However, its efficacy is compromised by mechanical degradation during transport through injection lines, valves, and reservoir, which leads to a reduction in the average molecular weight, diminishing the solution's viscosity and viscoelastic properties, critical for efficient oil displacement. In this investigation, we characterized the degree of mechanical degradation in HPAM solutions by evaluating shear and extensional rheological parameters preand post‐degradation. Mechanical degradation was induced by subjecting them to controlled flow through a valve featuring varying degrees of constriction and flow rates. Our results demonstrate a significant reduction in zero‐shear viscosity and high‐strain extensional viscosity of mechanically degraded solutions, with reductions of up to 64%. To mitigate this issue, we explored the incorporation of silica nanoparticles as a potential remedy for mechanical degradation. These nanoparticles strengthen the network structure of HPAM, thereby reducing its susceptibility to mechanical degradation. Our findings reveal that shear and extensional viscosities of mechanically degraded NPs‐HPAM solutions experienced only minimal reductions, dropping to 12% and 0%, respectively. This underscores the effectiveness of the nanoparticle‐enhanced HPAM solutions in preserving viscosity and viscoelasticity under mechanical stress, presenting a promising avenue for improving the robustness of EOR processes.

Effects of crystallization temperature on structure and digestibility of spherulites formed from debranched high-amylose maize starch

High-amylose maize starch (69.3 % amylose) was debranched to increase the level of linear molecules and enhance the formation of spherulites. Debranched high-amylose maize starch (25 %, w/w) was heated to 180 °C in a Parr reactor followed by crystallization at different temperatures between 25 and 150 °C. The objectives of this study were to investigate the effects of crystallization temperature on the yield, morphology, structure, crystallinity, and digestibility of the spherulites formed. When the crystallization temperature was 150 °C, spherulites with negative birefringent sign were formed. High crystallization temperature caused molecular degradation and the degree of degradation was severe at 150 °C, resulting in relatively short chain amylose (DP < 150). When crystallized at 25 to 120 °C, spherulites with strong positive birefringence were produced. The long chain amylose was attributed to the positive birefringence. All spherulites had a predominant B-type crystalline structure. The spherulites with negative birefringence showed a lower degree of crystallinity and lower resistance to enzyme digestion, but all the spherulites with positive birefringence had a high resistant starch content (89–94 %). α-Amylase was not able to penetrate inside the spherulites as revealed by the confocal laser scanning microscopic images.

The impact of military operations in 2022 on the wind-erosion hazard of the Ukrainian right bank

Wind erosion is caused by strong winds blowing continuously in one direction over unprotected vegetation or plant debris on the soil surface. It can be controlled by plant barriers such as forest belts. The military actions in 2022 as a result of Russian aggression dramatically changed the state of the existing network of forest belts. It was in the forest belts that the defense lines were built, which were subjected to the most intense artillery and rocket attacks and were the target of assault operations. Remote sensing methods, in particular Sentinel-2 satellite images for 2021 and 2022, were used to analyze changes in the condition of forest belts during hostilities in two research sites in Kherson and Mykolaiv regions. The Enhanced Vegetation Index (EVI) was used to determine the degree of forest degradation. The EVI index, in addition to the chlorophyll content of leaves, also responds to structural variations in the tree canopy, tree crown shape, and leaf area index. The index also takes into account the transmission of light through the tree canopy and the effect of atmospheric aerosols on brightness in the red region of the spectrum. In other words, the EVI index is very informative in terms of assessing the condition of forest belts as erosion control vegetation barriers. Studies have shown that most of the artificial forest plantations resulting from the hostilities in the spring and summer of 2022 can either perform their soil protection functions to a limited extent or are not able to counteract potential wind erosion at all. The loss of anti-erosion properties of forest belts as a result of military degradation leads to a significant increase in wind and erosion hazards. Calculations based on the WEQ methodology show that the potential volume of soil losses due to wind erosion from fields already unprotected by forest belts, plowed and without vegetation cover, increases from 3.9–4.7 t/ha per year to 7.0–8.4 t/ha per year, which often exceeds the permissible erosion rates and can lead to soil degradation and a decrease in soil fertility in the future. Post-war reforestation will take a long time, and therefore it is necessary to use fairly simple agrotechnical measures against wind erosion, in particular “conservation” tillage technologies, including no-till, which can stabilize the situation with wind-erosion soil degradation and fertility for a certain period of time.

Understanding the mechanism for sodium tripolyphosphate in improving the physicochemical properties of low-moisture extrusion textured protein from rapeseed protein and soybean protein blends

Our previous experiments found that rapeseed protein (RP) has applicability in low-moisture textured proteins. The amount of RP added is limited to <20 %, but the addition of 20 % RP still brings some negative effects. Therefore, in order to improve the quality of 20%RP textured protein, this experiment added different proportions of sodium tripolyphosphate (STPP) to improve the quality of the product, and studied the physical-chemical properties and molecular structure changes of the product to explore the possible modification mechanism. The STPP not only improved the expansion characteristics of extrudates, but also increased the brightness of the extrudates, the rehydration rate. In addition, STPP increased the specific mechanical energy during extrusion, decreased the material mass flow rate. Furthermore, STPP decreased the starch digestibility, increased the content of slow-digesting starch and resistant starch. STPP increased the degree of denaturation of extrudate proteins, the proportion of β-sheets in the secondary structure of proteins, as well as the intermolecular hydrogen bonding interactions. The gelatinization degradation degree of starch molecules also decreased with the addition of STPP. STPP also increased the protein-starch interactions and enhanced the thermal stability of the extrudate. All these indicate that STPP can improve the physical-chemical properties of extrudate.

Evolution characteristics and multi-scenario prediction of habitat quality in Yulin City based on PLUS and InVEST models

As a major energy city in China, Yulin City has faced huge challenges to the ecological environment with its rapid economic development and rapid urbanization. Therefore, it is of great significance to study the impact of land use changes on habitat quality. Based on three periods of land use data in Yulin City in 1995, 2005 and 2015, the PLUS model was used to simulate the land use changes in 2015. The measured kappa coefficient was 0.8859, which met the simulation accuracy requirements. By setting development zone boundaries and adjusting parameters, three progressive scenarios are designed to predict the spatial distribution of land use in Yulin City in 2035. The InVEST model was used to analyze the spatiotemporal evolution of Yulin City’s habitat quality in the past 20 years and evaluate the distribution of Yulin City’s habitat quality under three scenarios after 20 years. The results are as follows: (1) During the study period, construction land in Yulin City expanded rapidly, with an area increase of 380.87 km2 in 20 years, and ecological land gradually shrank. (2) The land use simulation results of Yulin City under various scenarios in 2035 show that future land use changes in Yulin City will mainly be concentrated in the central and western regions. (3) During the study period, the habitat quality of Yulin City was at a medium level and the overall habitat quality showed a downward trend. Spatially, the degree of habitat quality degradation in Yulin City showed a characteristic of gradually decreasing from West to East. (4) By 2035, under the scenario of suitable urban economic development, Yulin City’s habitat quality has been improved to a certain extent, which not only protects ecological security but also meets the demand for construction land for urban development. The results of this study help the government better understand the evolution of land use and habitat quality in Yulin City in the past 20 years, and provide theoretical support and reference for the formulation of Yulin City’s ecological environment protection policies and the implementation of ecological protection work under the current land spatial planning.

Nondestructive global corrosion measurement using guided wavefield data

Metallic structures often face degradation, and corrosion ranks among the most prevalent forms of deterioration. Accurate quantification of corrosion is crucial, especially for structures exposed to harsh environmental conditions, such as marine vessels and offshore installations. Because the traditional measurement methods based on scanning by ultrasonic gauge are time-consuming and provide only rough information on the thickness variability, there is a need to develop new robust and accurate diagnostics methods. This paper aims to investigate the corrosion monitoring of metal plates using guided wave propagation. Guided waves propagate within the entire volume of the specimen. If it is undamaged and isotropic, the velocity in all directions is the same, and the spreading wavefront takes a circular shape. The primary assumption presented in this paper is that the potential damage caused by corrosion leads to disturbance of this symmetry. The study shows Bilateral and Rotational Corrosion Symmetry Degree (BCSD and RCSD) functions, demonstrating a consistent decrease in symmetry values with increasing degree of degradation (DoD) caused by the corrosion process. The main aim of the study was to test the possibility of corrosion monitoring by using variable number of sensors comprising the transducer network. Also, the influence of the distance between the sensors affecting the size of the monitored area on the corrosion monitoring procedure was investigated. The paper contains the results of numerical and experimental campaigns conducted for corroded plates characterized by variable DoD and monitored using nine different transducers configurations. It is the first step in developing a novel measurement procedure specially designed for the ship and offshore industry. Therefore, because of the initial stage of the study, the last part of the paper discusses the limitations and drawbacks of the presented wave symmetry-based approach.

The Influence of Environmental Factors on the Degradation of PLA/Diatomaceous Earth Composites.

In the present study, tests were carried out on composite samples on a polylactide matrix containing 25% by weight of mineral filler in the form of diatomaceous earth, base, and silanized with GPTMOS (3-glycidoxypropyltrimethoxysilane), OTES (n-octyltriethoxysilane), and MTMOS (methyltrimethoxysilane) silanes. The addition of two types of waxes, synthetic polyamide wax and natural beeswax, were used as a factor to increase the rheological properties of the composites. The obtained samples were characterized in terms of the effect of filler silanization on the degradation rate of the composites. The tests were conducted under different conditioning conditions, i.e., after exposure to strong UV radiation for 250 and 500 h, and under natural sunlight for 21 days. The conditioning carried out under natural conditions showed that the modified samples exhibit up to twice the degradation rate of pure polylactide. The addition of synthetic wax to the composites increases the tendency to agglomerate diatomaceous earth, while natural wax has a positive effect on filler dispersion. For composites modified with GPTMOS and OTES silanes, it was noted that the addition of natural wax inhibited the degree of surface degradation, compared to the addition of synthetic wax, while the addition of MTMOS silane caused the opposite effect and samples with natural wax degraded more strongly. It was shown that, despite the high degree of surface degradation, the process does not occur significantly deep into the composite and stops at a certain depth.

Dynamic changes of tenderness, moisture and protein in marinated chicken: the effect of different steaming temperatures.

The steam processing characteristics of chicken are a key factor in the simplicity and versatility of steamed chicken dishes. The aim of this study was to investigate in depth the changes in tenderness and water retention of marinated chicken at different slow steaming endpoint temperatures, and to further explore the effect of the evolution of protein conformations on the water status. The results showed that chicken samples' shear force peaked at 80 °C and decreased rapidly at 90 °C. As the steaming endpoint temperature increased between 50 and 90 °C, T21, T22, moisture content and centrifugal loss decreased, but P21, P22 and myofibril water-holding capacity showed regular changes. The electrophoretic bands and protein conformation changes showed that protein in marinated chicken underwent different degrees of denaturation, degradation and aggregation. And at 70 °C, with an increase of hydrophobic groups and crosslinking of disulfide bonds as well as an increase in the number of denatured sarcoplasmic proteins, the intermolecular network was enhanced, thus affecting the water retention. Water status of chicken meat heated at different steaming temperatures is closely related to the evolution of protein conformations. The present study serves as a robust theoretical foundation for enhancing the quality of steamed chicken products at an industrial scale. © 2024 Society of Chemical Industry.

Biodegradation of Keratin Waste by Bacillus velezensis HFS_F2 through Optimized Keratinase Production Medium.

Enormous aggregates of keratinous wastes are produced annually by the poultry and leather industries which cause environmental degradation globally. To combat this issue, microbially synthesized extracellular proteases known as keratinase are used widely which is effective in degrading keratin found in hair and feathers. In the present work, keratinolytic bacteria were isolated from poultry farm soil and feather waste, and various cultural conditions were optimized to provide the highest enzyme production for efficient keratin waste degradation. Based on the primary and secondary screening methods, the potent keratinolytic strain (HFS_F2T) with the highest enzyme activity 32.65 ± 0.16 U/mL was genotypically characterized by 16S rRNA sequencing and was confirmed as Bacillus velezensis HFS_F2T ON556508. Through one-variable-at-a-time approach (OVAT), the keratinase production medium was optimized with sucrose (carbon source), beef extract (nitrogen source) pH-7, inoculum size (5%), and incubation at 37 °C). The degree of degradation (%DD) of keratin wastes was evaluated after 35days of degradation in the optimized keratinase production medium devoid of feather meal under submerged fermentation conditions. Further, the deteriorated keratin wastes were visually examined and the hydrolysed bovine hair with 77.32 ± 0.32% degradation was morphologically analysed through Field Emission Scanning Electron Microscopy (FESEM) to confirm the structural disintegration of the cuticle. Therefore, the current study would be a convincing strategy for reducing the detrimental impact of pollutants from the poultry and leather industries by efficient keratin waste degradation through the production of microbial keratinase.

Comparative and phylogenetic analyses of Loranthaceae plastomes provide insights into the evolutionary trajectories of plastome degradation in hemiparasitic plants

BackgroundThe lifestyle transition from autotrophy to heterotrophy often leads to extensive degradation of plastomes in parasitic plants, while the evolutionary trajectories of plastome degradation associated with parasitism in hemiparasitic plants remain poorly understood. In this study, phylogeny-oriented comparative analyses were conducted to investigate whether obligate Loranthaceae stem-parasites experienced higher degrees of plastome degradation than closely related facultative root-parasites and to explore the potential evolutionary events that triggered the ‘domino effect’ in plastome degradation of hemiparasitic plants.ResultsThrough phylogeny-oriented comparative analyses, the results indicate that Loranthaceae hemiparasites have undergone varying degrees of plastome degradation as they evolved towards a heterotrophic lifestyle. Compared to closely related facultative root-parasites, all obligate stem-parasites exhibited an elevated degree plastome degradation, characterized by increased downsizing, gene loss, and pseudogenization, thereby providing empirical evidence supporting the theoretical expectation that evolution from facultative parasitism to obligate parasitism may result in a higher degree of plastome degradation in hemiparasites. Along with infra-familial divergence in Loranthaceae, several lineage-specific gene loss/pseudogenization events occurred at deep nodes, whereas further independent gene loss/pseudogenization events were observed in shallow branches.ConclusionsThe findings suggest that in addition to the increasing levels of nutritional reliance on host plants, cladogenesis can be considered as another pivotal evolutionary event triggering the ‘domino effect’ in plastome degradation of hemiparasitic plants. These findings provide new insights into the evolutionary trajectory of plastome degradation in hemiparasitic plants.

The Use of Raman Spectroscopy to Assess the Degradation of Poly(p-dioxanone) Fibre Intended for Medical Purposes

Raman spectroscopy can be used in chemistry not just to determine chemical composition, but also to obtain further information on the material structure. In the spectra of semi-crystalline polymers, distinct bands characteristic of the crystalline or the amorphous phase can be found, the degree of crystallinity determined from them, and the degree of polymer degradation estimated from the crystallinity. In the present study, changes in the 1733 cm−1 band shoulder in Raman spectra of poly(p-di­oxanone) fibres subjected to hydrolytic degradation were evaluated. For different degradation periods, the areas under the shoulder of this band were calculated and a model deconvolution of this band into assumed crystalline and amorphous peaks was also performed. The areas under the shoulder, as well as the model peaks' parameters, were compared with the crystallinity values obtained by differential scanning calorimetry, achieving a good agreement. This work shows an example of using Raman spectroscopy when studying the hydrolytic degradation of polymers.

Study of Bacterization of Medicago sativa L. and Cynodon dactylon (L.) Pers. During the Process of Phytoremediation of Oil-contaminated Soils

Recultivation of oil-contaminated soils on the Absheron Peninsula is one of the most important environmental and social problems for this region. One of the promising ways to solve the problem of soil pollution with petroleum hydrocarbons is the development of methods and approaches for their purification and detoxification in situ, and above all, biodetoxification and bioremediation. In a model vegetation experiment using complex systems of a mixture of plants and microorganisms, phytoremediation of soil contaminated with crude oil at a concentration of 15 g/kg was investigated. It has been established that the inoculation of plants with the modified Fermi-Start biological product affects the number of rhizosphere microorganisms that stimulate plant growth, as well as the degree of purification of gray-brown soil from oil. Cynodon dactylon is an effective biosystem for the remediation of oil-contaminated gray-brown soils as it is modified by a culture of an oil-oxidizing microorganism of the Pseudomonas aeruginosa, isolated from oil-contaminated gray-brown soil, the Fermi-Start biological product and belongs to the group of “effective microorganisms”, associated with plants — Medicago sativa. The joint introduction of the Fermi-Start biological product and the culture of P. aeruginosa had the greatest protective effect on seedlings from exposure to crude oil. The height of the shoots increased by 71% compared with the negative control, in parallel, the degree of oil degradation increased to 24%. A significant role of alfalfa in stimulating the number of rhizosphere microorganisms capable of hydrocarbon degradation has been revealed. This is confirmed by data showing that the number of microorganisms in the plant rhizoplane was 1–2 orders of magnitude higher (about 1.1×107 on average) than in the rhizosphere (about 1.4×105 on average), which may be due to secretion of plant root exudates. The results of the research allow us to recommend the use of a plant-microbial biosystem consisting of Medicago sativa and Cynodon dactylon, together with a Fermi-Start modified biological product for phytoremediation of gray-brown soil contaminated with crude oil.

Investigation of corrosion resistance and interfacial bonding properties of silver/silicone zinc-rich coating/substrate system in marine environment

This paper aims to study the corrosion resistance and interfacial bonding properties of the silver zinc-rich coating/substrate system and silicone zinc-rich coating/substrate system. The actual working state of the system in marine environment was simulated by the coupled effects of corrosion and pre-stretching. Scanning electron microscope (SEM) with an energy dispersive X-ray spectrometer (EDS) was used in corrosion test to analyze the surface morphology and corrosion products. Meanwhile, the degradation degree of the corrosion resistance was investigated based on the electrochemical impedance spectroscopy (EIS) and water absorption rate. Three-point bending test and tensile test combined with digital image correlation (DIC) were performed to evaluate the interfacial bonding properties of these two systems based on the elastic modulus and critical cracking strain. Results show that the dense accumulation of aluminum and zinc powders makes the silver zinc-rich coating have higher corrosion resistance compared to the silicone zinc-rich coating. The combined effects of corrosion and pre-stretching on the fracture toughness of silicone zinc-rich coating are larger than that of the silver zinc-rich coating. The interfacial bonding properties of the coating/substrate systems gradually degrade as the pre-stretching load approaches the critical cracking load of the coating.

Genomic, Phylogenetic and Physiological Characterization of the PAH-Degrading Strain Gordonia polyisoprenivorans 135.

The strain Gordonia polyisoprenivorans 135 is able to utilize a wide range of aromatic compounds. The aim of this work was to study the features of genetic organization and biotechnological potential of the strain G. polyisoprenivorans 135 as a degrader of aromatic compounds. The study of the genome of the strain 135 and the pangenome of the G. polyisoprenivorans species revealed that some genes, presumably involved in PAH catabolism, are atypical for Gordonia and belong to the pangenome of Actinobacteria. Analyzing the intergenic regions of strain 135 alongside the "panIGRome" of G. polyisoprenivorans showed that some intergenic regions in strain 135 also differ from those located between the same pairs of genes in related strains. The strain G. polyisoprenivorans 135 in our work utilized naphthalene (degradation degree 39.43%) and grew actively on salicylate. At present, this is the only known strain of G. polyisoprenivorans with experimentally confirmed ability to utilize these compounds.

Comparison of the Sample Preparation Strategies and Impacts on the Tensile Strength of Gas Shale with Variable Moisture Conditions

Moisture significantly affects the mechanical behavior of gas shale and further determines the hydraulic fracturing performance, as it is more attractive. Nevertheless, batch experiments have usually involved variable methodologies regarding the preparation of moisture-contained shale specimens in the sequence (and/or frequency) of drying and soaking treatments. Accordingly, this work investigates how the preparation methodology influences the test results of moisture-contained shale samples. This study compares three commonly used shale sample preparation strategies for acquiring different moisture contents, that is, “dry-wet”, “dry-wet-dry”, and “wet-dry-wet” strategies, followed by a Brazilian splitting test for the mechanical parameters. The results show that under the same saturation conditions, the longer the soaking time during sample preparation, the higher the degradation degree of shale tensile strength. Meanwhile, prolonged soaking can lead to a more discrete distribution of strength values, and the failure mode may deviate from the Brazilian splitting theory model. Under the combined influence of moisture content and soaking time, the tensile strength of shale decreases approximately linearly with increasing saturation, while the degradation degree increases nonlinearly with increasing saturation, and the degradation rate changes from slow to fast. According to the observation of the microstructure of hydrated shale, prolonged soaking can lead to an increase in the expansion of clay minerals in shale by hydration, resulting in looser and more fragmented internal structure, and further degradation in shale strength. In order to weaken the interference of hydration when studying the effect of moisture content on the tensile strength of shale, the soaking time should be minimized as much as possible during the preparation process.

Evaluation of the Degree of Degradation of Brake Pad Friction Surfaces Using Image Processing

The improvement of drilling rig systems to ensure a reduction in unproductive time spent on lowering and lifting operations for replacing drilling tools and restoring the performance of drilling equipment units is an important task. At the same time, considerable attention is paid to the reliable and efficient operation of the braking systems of drilling rig winches. In the process of operation, the polymer pads periodically come into contact with the outer cylindrical surface of the metal pulley during braking, work in extreme conditions and wear out intensively, so they need periodic replacement. Tests were carried out on a modernized stand and in industrial conditions for the brakes of drilling winches. A methodology for evaluating the degradation of the brake pad friction surface during its operation is proposed. The assessment of the degradation degree is carried out based on the image of the brake pad surface using image processing techniques. Geometric transformations of the input image were performed to avoid perspective distortions caused by the concave shape of the brake pads and the spatial angle at which the image is acquired to avoid glares. The crack detection step was implemented based on the scale-space theory, followed by contour detection and skeletonization. The ratios of the area and perimeter of segmented and skeletonized cracks to the total area were chosen as integral characteristics of the degradation degree. With the help of scanning electron microscopy, the character of the destruction of the friction surface and the degradation of the polymer material was investigated. Experimental studies were performed, and the application of the proposed method is illustrated.

Experimental study on the seismic performance of GFRP-stiffened steel plate shear walls

This study conducted experimental investigations to evaluate the seismic performance of steel plate shear wall (SPSW) with infilled flat and corrugated steel plates stiffened by GFRP plates. Four half-scale specimens were subjected to cyclic quasi-static tests, comprising two specimens with ordinary flat and corrugated steel plates, and two specimens with flat and corrugated steel plates reinforced by GFRP plates. The objective of this study was to reveal how the form of steel plates (flat or corrugated) and the arrangement of GFRP plates influenced the seismic performance of SPSW. The research discussed the failure modes, lateral load-bearing mechanism, ultimate shear resistances, and energy-dissipating capacities of the different specimens. The experimental findings demonstrated that incorporating GFRP plates provided more effective reinforcement for corrugated SPSW compared to flat SPSW. According to the experimental data, the ultimate lateral load-bearing capacity, ductility, and energy-dissipating of the GFRP-stiffened corrugated steel plate shear wall have been increased by 9.3%, 46.4%, and 79.9% respectively compared with the unstiffened one, and the degree of stiffness degradation has been reduced by 10.2%. The findings of this study will provide important references for subsequent research on GFRP-stiffened steel plate shear walls.

Transformation of polyester fibre microplastics by sulfate based advanced oxidation processes

Advanced oxidation processes (AOPs) are a potential solution to microplastics (MPs) polluted wastewater but incomplete degradation can result in the formation of smaller fragments with altered surface chemistry. In this work, the impact of sulfate based oxidation on polyester MPs was investigated. Light, heat and ultrasound activation of persulfate resulted in varied degrees of mass loss and surface degradation, as probed by scanning electron microscopy (SEM), atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR). Ultrasonic activation of persulfate resulted in significantly increased fragmentation and formation of smaller microplastic fibrils. Optimised UVC/peroxydisulfate (UVC/PDS) treatment (31.8 mW cm−2, 500 mg L−1) resulted in an 18.5% mass loss over 9 h with clear surface pitting and cracking. Extended treatment under these conditions for 24 h did not result in significantly increased mass loss but did cause an increased degree of surface degradation and increased roughness, indicating that incomplete mineralisation is likely in wastewater systems accompanied by MP transformation. The influence of a real laundry wastewater matrix was also studied and a decreased rate of mass loss was observed due to competing radical reactions with the organic content of the wastewater. Results advance understanding and therefore contribute to mitigating water pollution by MPs, since their physical and chemical transformation in real water treatment systems substantially affects the interaction with organic contaminants and changes the potential environmental risk of MPs.