Disintegration Rate Research Articles

Exploring the efficacy of biosynthesized cupric oxide nanoparticles from Jasminum sambac flower extract in wastewater treatment: Experimental investigations and potential applications

Researchers have shown significant interest in the creation of sustainable green techniques for synthesising metal oxide nanomaterials in the past few years. Plant-mediated production is considered an affordable and feasible alternative to traditional physical and chemical approaches. This study presents a straightforward approach for the environmentally friendly production of copper oxide nanoparticles (CuO NPs) by a solution combustion technique utilising Jasminum sambac Flower Extract. The CuO NPs produced during biosynthesis were analysed using UV-Vis, XRD, FT-IR, SEM, TEM, HPLC, BET and EDX techniques. The SEM pictures reveal that the fragments possess a sponge-like structure characterised by a substantial surface area. An investigation into the photocatalytic activity of CuO NPs shows that they are effective as a catalyst for the breakdown of methylene blue (MB) when exposed to UV and solar radiation. Furthermore, the study demonstrated a pH dependence in the breakdown of MB. According to the study, the best starting concentration of dye for breaking down things completely is 2.5 parts per million (ppm), which results in a remarkable 79 % disintegration rate. The findings indicate that CuO NPs have the ability to effectively treat water by decomposing contaminants such as methylene blue, providing a sustainable method for treating wastewater.

Calorimetric investigation on heat release during the disintegration process of pharmaceutical tablets

The compendial USP〈701〉 disintegration test method offers a crucial pass/fail assessment for immediate release tablet disintegration. However, its single end-point approach provides limited insight into underlying mechanisms. This study introduces a novel calorimetric approach, aimed at providing comprehensive process profiles beyond binary outcomes. We developed a novel disintegration reaction calorimeter to monitor the heat release throughout the disintegration process and successfully obtained enthalpy change profiles of placebo tablets with various porosities. The formulation comprised microcrystalline cellulose (MCC), anhydrous lactose, croscarmellose sodium (CCS), and magnesium stearate (MgSt). An abrupt temperature rise was observed after introducing the disintegration medium to tablets, and the relationship between the heat rise time and the tablet’s porosity was investigated. The calorimeter’s sensitivity was sufficient to discern distinct heat changes among individual tablets, and the analysis revealed a direct correlation between the two. Higher porosity corresponded to shorter heat rise time, indicating faster disintegration rates. Additionally, the analysis identified a concurrent endothermic process alongside the anticipated exothermic phenomenon, potentially associated with the dissolution of anhydrous lactose. Since lactose is the only soluble excipient within the blend composition, the endothermic process can be attributed to the absorption of heat as lactose molecules dissolve in water. The findings from this study underscore the potential of utilising calorimetric methods to quantify the wettability of complex compounds and, ultimately, optimise tablet formulations.

Release dynamics of nanodiamonds created by laser-driven shock-compression of polyethylene terephthalate

Laser-driven dynamic compression experiments of plastic materials have found surprisingly fast formation of nanodiamonds (ND) via X-ray probing. This mechanism is relevant for planetary models, but could also open efficient synthesis routes for tailored NDs. We investigate the release mechanics of compressed NDs by molecular dynamics simulation of the isotropic expansion of finite size diamond from different P-T states. Analysing the structural integrity along different release paths via molecular dynamic simulations, we found substantial disintegration rates upon shock release, increasing with the on-Hugnoiot shock temperature. We also find that recrystallization can occur after the expansion and hence during the release, depending on subsequent cooling mechanisms. Our study suggests higher ND recovery rates from off-Hugoniot states, e.g., via double-shocks, due to faster cooling. Laser-driven shock compression experiments of polyethylene terephthalate (PET) samples with in situ X-ray probing at the simulated conditions found diamond signal that persists up to 11 ns after breakout. In the diffraction pattern, we observed peak shifts, which we attribute to thermal expansion of the NDs and thus a total release of pressure, which indicates the stability of the released NDs.

Effect of Modifiers on the Disintegration Characteristics of Red Clay

Due to the high degree of weathering, the red clay slope has low anti-disintegration performance, and the clay easily becomes wet and disintegrates after soaking in water. It causes geological problems such as slope collapse caused by soil softening. To study the disintegration characteristics of modified red clay, the disintegration test of red clay modified by using lignin fiber, clay particles and lime was carried out, analyzing the disintegration characteristics of improved red clay from physical and chemical perspectives and analyzing the improvement mechanism of three modifiers with the scanning electron microscopy test. The analysis results show that the water-holding capacity and disintegration resistance of soil mixed with lignin fiber decrease; the disintegration time of reshaped red clay increases with the increase in clay content; and the average disintegration rate of the soil decreases with the increase in clay content. With the increase in lime content, the soil cement increases. The integrity of the soil is enhanced, and its anti-disintegration ability is improved; the saturated moisture content of reshaped red clay increases with the increase in lignin fiber and clay content, while the saturated moisture content of soil decreases with the increase in lime content. The damage analysis shows that the larger the damage factor of soil, the worse its anti-disintegration ability, and the easier the soil disintegrates. The purpose of this paper is to explore the essence of the soil disintegration phenomenon, and on this basis, using high-quality improved materials, to improve the soil, which easily disintegrates. This move aims to significantly enhance the anti-disintegration ability of the soil, thereby improving its resistance to softening and disintegration, thereby effectively improving and maintaining the ecological environment. At the same time, the improved soil will help to improve the utilization rate of the slope and foundation soil, thereby reducing the economic cost of maintenance engineering. Against the current background of sustainable economic, social, and ecological development, it is of great strategic significance to ensure the sustainable availability of land resources in specific areas and maintain their productivity and ecological stability for a long time. The research into this subject not only helps to deepen the understanding of soil disintegration, but also provides strong technical support for the rational utilization of land resources and the protection of the ecological environment.

Design Formulation and Evaluation of Anti Migraine Mouth Dissolving Tablets Using Different Super Disintegrants

The main objective of this research was to create and evaluate the efficacy of orally disintegrating tablets containing sumatriptan succinate at a dosage of 25 milligrammes, a medicine commonly prescribed for the treatment of migraines. The tablets are made using the direct compression method. In order to achieve best results, the formulations were enriched with microcrystalline cellulose of varying composition (Avicel PH 102), mannitol as a diluent, crospovidone, croscaramellose, and sodium starch glycollate as superdisintegrants. Carbomer (carbopol 940), Sodium CMC, and Sodium Alginate were among the other excipients that were used. When used at varying doses, these excipients act as disintegrants. In addition, magnesium stearate was used as a substance to reduce friction, while talc was used as a substance to improve flow. We assessed each of the excipients to ascertain their compatibility with the model drug. The findings revealed no occurrence of any physical or chemical interaction. Before compression, the preformulation features of the tablet blend were examined. The criteria considered were bulk density, tapped density, compressibility index, and hausner ratio. An assessment was carried out on central tablets to ascertain their dimensions, firmness, tendency to crumble, variability in weight, rate of disintegration, and uniformity of drug content properties. Furthermore, an investigation was conducted to examine the impact of these variables on the release of the drug. The drug release studies were performed in vitro using the USP dissolving apparatus-II (paddle type) with a phosphate buffer solution at a pH of 6.8. The experiments were conducted at a speed of 50 revolutions per minute at a temperature of 37 degrees Celsius, with a standard deviation of 5 degrees Celsius. The sampling was conducted at consistent intervals of 2, 4, 6, 8, and 10 minutes. After each withdrawal, an equivalent volume of dissolving medium was replaced with the sample. The ultraviolet (UV) method is employed to evaluate the cumulative quantity of medications that have been discharged at different time intervals. Based on the evaluation results, the F-3 trial formulation, which included 6% crospovidone, was selected as the superior formulation among the superdisintegrants. Conversely, the F-10 trial formulation, which included 2% carbopol 940p, was selected as the superior formulation compared to other basic disintegrants.

Stabilization of micaceous residual soil with industrial and agricultural byproducts: Perspectives from hydrophobicity, water stability, and durability enhancement

Micaceous residual soil is prevalent in the tropical regions of southern China. However, it is generally deemed unsuitable as a construction material in earthen structures due to its inferior engineering properties. Despite previous research into stabilizing micaceous soils, there remains an urgent demand for sustainable alternatives to traditional stabilizers to achieve circularity. Furthermore, uncertainties regarding the long-term performance of stabilized soils under hydraulic conditions complicated their use in flood-susceptible areas. To provide a sustainable and low-cost solution for creating stabilized soil for earthen structures in waterlogged regions, this study explores the impact of coir fiber and fly ash, agricultural and industrial byproducts, on the hydrophobicity, durability, and water stability of micaceous residual soil from Hainan, China. The study commenced with the preliminary mechanical tests to ascertain the optimal dosage of coir fiber and fly ash, which were determined to be 1% and 15%, respectively. Then, hydrophobicity, durability, and disintegration tests are conducted on fiber-reinforced fly-ash-treated soil under various stabilization conditions. The microstructural evolution of the soil fabric in response to the stabilization process was meticulously traced using scanning electron microscopy and energy-dispersive spectroscopy. Results indicated that the addition of fly ash could impart severe and persistent water repellency to the studied soil, with the contact angle improving from 16.7° to 102.9°, and the water drop penetration time significantly extending from 3.6 s to approximately 600 s. While incorporating coir fibers into the cemented soil presented negligible improvement on soil hydrophobicity, it markedly enhanced the soil’s durability, mitigated moisture-related deterioration and decelerated disintegration. Notably, the strength residual ratio of fiber-reinforced cemented sample maintained higher than 90% even after 20-day water immersion, and the disintegration rate decreased by 57% compared to unreinforced sample. Microstructural analysis revealed that bonding, friction, and interlocking among fibers, hydration products, and soil particles are the main contributors to the stable and robust matrix, ensuring improved mechanical behavior and longevity of micaceous residual soil. This study provides an innovative method for utilizing waste byproducts in stabilizing micaceous residual soil, as a viable option for earthworks in rain-soaked or flood-prone areas.

Study on Mudcake disintegration in clayey strata during shield tunneling: Effects of dispersants and bentonite slurry

While tunnel boring machines (TBMs) tunneling in clayey strata, the adhered excavated soil on the cutterhead and cutting tools tends to form mudcake after compaction and consolidation. Mudcake can obstruct the cutterhead openings and rendering the cutting tools ineffective, leads to a substantial reduction in advance rate. Dispersants are recognized as an effective method for the disintegration of mudcakes. A novel set of equipment, comprising a mudcake compression device and a mudcake disintegration apparatus, is developed for assessing mudcake disintegration properties. The results showed that mudcakes underwent a tripartite disintegration process in water, including an initial stage, a rapid disintegration stage, and a stable stage. In the initial stage, the mudcakes absorbed water before disintegration, resulting in marginal changes in the weight of the disintegrated mudcakes. In the rapid disintegration stage, the weight of the disintegrated mudcakes increased quickly. During the stable stage, the weight of the disintegrated mudcakes remained relatively constant. The submersion of mudcakes in a dispersant solution substantially increased the rate of disintegration. Greater dispersant concentration corresponded to an increase in the disintegration rate. No weight gain was observed in mudcakes during the initial disintegration stage. When mudcakes disintegrated in a bentonite slurry, the weight of the disintegrated mudcakes initially decreased and then stabilized. The weight of the disintegrated mudcakes turned negative, indicating an increase in the weight of mudcakes. This suggested that bentonite significantly hindered mudcake disintegration.

Study on the Influence of Moisture Content and Void Ratio on the Disintegration of Red Clay

Guilin is a famous karst area, and currently the view that the disintegration of red clay will cause soil cave collapse is increasingly recognized. In order to study the influence of the coupling effect of moisture content and void ratio on the disintegration of red clay, different moisture contents and void ratios of Guilin red clay were placed on a self-made disintegration apparatus to record the real-time disintegration amount and observe the disintegration phenomenon. Images of the structural characteristics of soil were obtained by a scanning electron microscope (SEM). Additionally, nuclear magnetic resonance (NMR) was applied to analyze the distribution of water in both natural and saturated states. The results show that the disintegration rate of red clay decreases as the initial moisture content increases, but increases with the increase of void ratio. Both moisture content and void ratio affect the structural characteristics of red clay. When the moisture content remains constant, the soil changes from a three-peak to a two-peak structure as the void ratio increases. The total area and secondary peak area of the T2 spectrum increase, while the starting T2 value of the main peak shifts to the right and the area decreases. Meanwhile, the starting T2 value of the secondary peak shifts to the right and the area increases. When the void ratio remains constant, the starting T2 value of the main peak gradually shifts to the left and the area decreases as the moisture content increases. However, the starting T2 value of the secondary peak shifts to the right and the area decreases or first decreases and then increases. The disintegration rate does not exhibit a significant relationship with either pore volume or macropore volume. The combined water saturation shows a bilinear relationship with both the moisture content and void ratio, where it increases as the initial moisture content increases, but decreases as the void ratio increases, with a correlation coefficient of 0.9929. The disintegration rate has an exponential relationship with the combined water saturation, and it decreases as the combined water saturation increases, with a correlation coefficient of 0.9934.

Powder bed fusion–laser beam (PBF-LB) three-dimensional (3D) printing: Influence of laser hatching distance on the properties of zolpidem tartrate tablets

Laser sintering, known as powder bed fusion–laser beam (PBF-LB), offers promising potential for the fabrication of patient-specific drugs. The aim of this study was to provide an insight into the PBF-LB process with regard to the process parameters, in particular the laser hatching distance, and its influence on the properties of zolpidem tartrate (ZT) tablets. PHARMACOAT® 603 was used as the polymer, while Candurin® Gold Sheen and AEROSIL® 200 were added to facilitate 3D printing. The particle size distribution of the powder blend showed that the layer height should be set to 100 µm, while the laser hatching distance was varied in five different steps (50, 100, 150, 200 and 250 µm), keeping the temperature and laser scanning speed constant. Increasing the laser hatching distance and decreasing the laser energy input led to a decrease in the colour intensity, mass, density and hardness of the ZT tablets, while the disintegration and dissolution rate were faster due to the more fragile bonds between the particles. The laser hatching distance also influenced the ZT dosage, indicating the importance of this process parameter in the production of presonalized drugs. The absence of drug-polymer interactions and the amorphization of the ZT were confirmed.

Orally self-disintegrating milk protein-based puffs enriched with in-process generated short chain galacto-oligosaccharides by supercritical fluid extrusion

This study aimed to design and evaluate orally self-disintegrating puffs that are nutritionally enhanced via in-process polymerization of galactose into galacto-oligosaccharides (GOS). Lactose hydrolyzed (LHSMP) or unhydrolyzed skim milk powder (SMP) was combined with 80% protein milk protein concentrate (MPC) powder and a calcium chelator, then processed using supercritical fluid extrusion (SCFX) with carbon dioxide (CO2) to produce protein-rich orally self-disintegrating puffs. Disintegration results indicate the MPC90 and MPC70-SMP20 puffs had faster disintegration rates (3.20 and 3.84%/sec) than the commercial puffs (3.12%/sec). Galactose in LHSMP as a precursor to formation of polymeric GOS during extrusion was also investigated. The low pH and controlled temperature minimize Maillard browning and enhanced the polymerization of galactose into GOS. The MPC60-LHSMP30 puffs had the highest content of short chain GOS (2.3 wt%). The current study provides first valuable insights for the utilization of LHSMP to produce orally self-disintegrating GOS enriched protein puffs.

Elevation-related variations of soil disintegration and its driving forces in the water level fluctuation zone of the Three Gorges Reservoir, China

Soil disintegration is a key process of the early stages of soil erosion. The water level fluctuation zone (WLFZ) in reservoirs undergoes seasonal changes involving periodic alternations in inundation and exposure that can affect soil disintegration. In this study, we conducted experiments on pre-wetted undisturbed soil samples obtained from different elevations ranging from 155 to 180 m a.s.l. and different soil depths (0–10 and 10–20 cm) in the WLFZ of the Three Gorges Reservoir (TGR), upper Yangtze River, China. We investigated how soil disintegration varies depending on elevation within the WLFZ and used principal component analysis (PCA) and stepwise regression to identify the dominant variables affecting soil disintegration. Results show the following: (1) The disintegration ratio, which is a measure of the amount of soil disintegration that occurs during experiments, varied in the range of 0.45 %–4.79 % over 60 min, with 79 %–100 % of the disintegration occurring within the first 30 min. The disintegration ratio increases with decreasing elevation in the WLFZ. Soil samples from a depth of 0–10 cm disintegrated 0.43 % less on average than those from a depth of 10–20 cm. The relationship between disintegration rate and elevation can be expressed using an exponential function with R2 > 0.80. (2) The main variables loading onto the first three principal components (explain 91.4 % of the variation in all variables) identified by PCA were those involving soil aggregates, the plant root system, and soil particle-size, respectively. (3) Stepwise regression identified >0.25 mm water-stable aggregate content (Ws0.25) and root mean diameter (Droot) as the strongest predictors of soil disintegration and yielded a linear regression equation with R2 = 0.88. Ws0.25 and Droot were the most influential variables on the elevation-dependent occurrence/degree of disintegration. Such information is essential for understanding the occurrence and prevention of bank erosion in reservoir areas.

Flexible modelling of the dissolution performance of directly compressed tablets

In this study, a compartmental disintegration and dissolution model is proposed for the prediction and evaluation of the dissolution performance of directly compressed tablets. This dissolution model uses three compartments (Bound, Disintegrated, and Dissolved) to describe the state of each particle of active pharmaceutical ingredient. The disintegration of the tablet is captured by three fitting parameters. Two disintegration parameters, β0 and βt,0, describe the initial disintegration rate and the change in disintegration rate, respectively. A third parameter, α, describes the effect of the volume of dissolved drug on the disintegration process. As the tablet disintegrates, particles become available for dissolution. The dissolution rate is determined by the Nernst-Brunner equation, whilst taking into account the hydrodynamic effects within the vessel of a USP II (paddle) apparatus. This model uses the raw material properties of the active pharmaceutical ingredient (solubility, particle size distribution, true density), lending it towards early development activities during which time the amount of drug substance available may be limited. Additionally, the strong correlations between the fitting parameters and the tablet porosity indicate the potential to isolate the manufacturing effects and thus implement the model as part of a real-time release testing strategy for a continuous direct compression line.

Effect of different buried depth on the disintegration characteristic of red-bed soft rock and the evolution model of disintegration breakage under cyclic drying-wetting

The disintegration of red-bed soft rock exhibits a strong correlation with various geological disasters. However, the investigation into the evolutionary mechanisms underlying disintegration breakage has not yet received extensive exploration. In order to comprehensively examine the disintegration characteristics of red-bed soft rock, the slake durability tests were conducted to red-bed soft rocks of varying burial depths. Subsequently, an investigation was carried out to examine the disintegration characteristics and the evolution of disintegration parameters, including the coefficient of uniformity (Cu), coefficient of curvature (Cc), disintegration rate (DRE), disintegration ratio (Dr), and fractal dimension (D), throughout the disintegration process. Finally, employing the energy dissipation theory, an energy dissipation model was developed to predicate the disintegration process of samples at various burial depths. The findings demonstrate a decrease in the abundance of large particles and a concurrent increase in the abundance of small particles as the number of drying-wetting cycles increases. Furthermore, as the number of drying-wetting cycles increases, a significant alteration is observed in the content of particles larger than 10 mm, whereas the content of particles smaller than 10 mm undergoes only minor changes. The disintegration parameters, including the curvature coefficient, non-uniformity coefficient, disintegration rate, and fractal dimension, exhibit a positive correlation with the number of drying-wetting cycles. Conversely, the disintegration index demonstrates a decreasing trend with the increasing number of cycles. Nevertheless, as the burial depth increases, a notable trend emerges in the disintegration process, characterized by a gradual increase in the content of large particles alongside a progressive decrease in the content of small particles. Concurrently, the curvature coefficient, non-uniformity coefficient, disintegration rate, and fractal dimension exhibit a gradual decline, while the durability index experiences a gradual increase. In addition, based on the principle of energy dissipation, it is revealed that the surface energy increment of red-bed soft rock increases with the increase of the number of drying-wetting cycles, but decreases with the increase of burial depth. Ultimately, by leveraging the outcomes of energy dissipation analyses, a theoretical model is constructed to elucidate the correlation between surface energy and both the number of drying-wetting cycles and burial depth. This model serves as a theoretical reference for predicting the disintegration behavior of samples, offering valuable insights for future research endeavors.

Development of soy protein isolate-based orally disintegrating film: Improvement of disintegration speed, mechanical properties, and thermal stability by β-Cyclodextrin

The effect of β-Cyclodextrin (β-CD) at different concentrations (0–20% w/w) on the function and properties of soy protein isolate (SPI)-based orally disintegrating films (ODF) was studied. The results of moisture content and contact angle indicate that the inclusion of β-CD enhances the moisture content and surface hydrophilicity of ODF. The thickness ODF samples is between 0.031 and 0.041 mm. Due to the addition of β-CD, ODF disintegration rates increased by 47.86%–64.62%. Scanning electron microscope, and mechanical analysis show that ODF with a β-CD concentration of 10% w/w has the best performance, presenting the smoothest surface, maximum tensile strength (TS) and elongation at break (EB). FTIR spectrum results show that there are physical entanglements and hydrogen bonding interactions between SPI and β-CD, and appropriate concentrations of β-CD (5% w/w and 10% w/w) can transform random coils into β-sheets. Once the concentration exceeding 10% w/w, β-CD will crystallize and precipitate on the ODF surface, which weakens the mechanical properties of the ODF and the strength of the SPI network structure. Thermogravimetric test results show that β-CD improves ODF thermal stability. This research offers a significant theoretical foundation for the advancement of ODF that are protein-based and not hydrolyzed.

Review Article: Early Recurrent Pregnancy Loss

Recurrent pregnancy loss, which affects 2%–5% of individuals, is just a significant concern for women's health. Uterine malformations, antiphospholipid syndrome, metabolic or endocrine diseases, as well as chromosomal abnormalities are among the often reported established reasons. Alternative aetiologies, like chronic uterine infections, hereditary thrombophilias, luteal stage insufficiency, or excessive male DNA disintegration rates, have been put forward yet remain regarded as debatable. The results for individuals who experience recurrent miscarriage had increased throughout time because to evidence-based therapies including surgical repair of chromosomal abnormalities, aspirin as well as anticoagulation in anticardiolipin disorder. About 50% of the instances, though, are still unsolved, so they are managed effectively with estrogen augmentation, anticoagulation, and/or immunostimulatory therapies. Regardless of the reason, couples who experience recurrent fetal death have a favourable long-term outlook and also the majority ultimately has a safe live delivery. Several miscarriages, though, may have a major psychological impact just on afflicted people, and numerous attempts are now being undertaken to enhance therapies or shorten the time it takes to conceive successfully. With an emphasis on inexplicable repeated fetal loss as well as the current usage of empiric therapies, this article reviews the recognised or contentious aetiologies as well as the suggested therapeutic approaches. As well, it covers the present use of pre - implantation genetic screening inside the treatment of repeated miscarriages.

Zeolitic imidazolate framework@hydrogen titanate nanotubes for efficient adsorption and catalytic oxidation of organic dyes and microplastics

Metal-organic frameworks (MOFs) have significant promise as materials for many environmental applications, namely in the realm of water treatment. In this study, we produced a nanocomposite material by combining zeolitic imidazolate frameworks (ZIF-67) with hydrogen titanate nanotubes (HTNT) at ambient temperature. The materials, namely HTNT, ZIF-67, and HTNT@ZIF-67, were analyzed and employed for the adsorption and catalytic oxidation of water pollutants such as organic dyes (fluorescein acid (FL), Rhodamine B (RhB), direct blue I (DB), and basic fuchsin (BF)) and microplastics extracted from personal care and cosmetics products. The HTNT@ZIF-67 nanocomposite exhibited dye removal efficiencies of 99% and 97% for adsorption and catalytic oxidation by hydrogen peroxide (H2O2), respectively. ZIF-67 exhibits the most rapid disintegration rate among the tested substances, with rates of 517, 439, 1764, 1764, and 1621 mL/min·g for H2O2 and H2O2 in the presence of FL, RhB, DB, and BF, respectively. The catalytic degradation process may be used for up to six cycles, while maintaining an efficiency of 78%. Catalysts based on ZIF-67, such as HTNT@ZIF-67, show great potential for removal targeting organic contaminants such dyes and microplastics.

Disintegration characteristics of sodic–saline loessial soil after freeze–thaw and wet–dry cycles

AbstractGeological hazards such as gully erosion, collapse and slope failure occur frequently in loess areas, which are closely related to the soil disintegration characteristics. Understanding the impact of freeze–thaw and wet–dry action on soil disintegration in the context of climate change is essential to establish effective soil and water conservation strategies and prevent engineering geological hazards in loess areas. In this study, sodic–saline loessial soils with different clay content were subjected to freeze–thaw and wet–dry cycles, followed by aggregate durability tests, direct shear tests and disintegration tests to investigate the effects of the two natural processes on soil disintegration characteristics. The results showed that the samples subjected to freeze–thaw cycles primarily exhibited rapid and stable disintegration, followed by slow disintegration, whereas the samples subjected to wet–dry cycles revealed weight gain, continuous slow disintegration and eventual sudden disintegration. Freeze–thaw action continuously deteriorated the disintegration resistance of soil, while wet–dry action improved the disintegration resistance of soil after the first cycle, and gradually weakened it in subsequent cycles. Statistical analysis showed that, for samples undergoing freeze–thaw cycles, the number of cycles and clay content were positively correlated with the disintegration rate, while the aggregate durability was negatively correlated with the disintegration rate. For samples undergoing wet–dry cycles, the number of cycles had a positive effect on the disintegration rate, while the clay content, shear strength and cohesion had a negative correlation with the disintegration rate. At a certain clay content, there was a positive correlation observed between the surface crack ratio, crack length and width with the disintegration rate of the wet–dry samples, while shear strength and cohesion had a negative correlation with the disintegration rate of both freeze–thaw and wet–dry samples. Furthermore, the study outlined the disintegration mechanism of loessial soils based on internal factors, driving factors, resistance factors and evolutionary factors. This study contributes to the in‐depth understanding of the catastrophic mechanism of geological hazards in cold and arid areas and provides experimental evidence for its control and management.

Activity of Bambusa vulgaris extract in reducing silver nanoparticles: evaluation against methylene blue organic pollutant and microbial agents

This article presents an investigation focusing on successfully synthesising silver nanoparticles with zero valences. The synthesis involves utilising an extract from bamboo leaves, specifically those obtained from the Bambusa vulgaris species. X-ray diffraction, transmission electron microscopy, Fourier transform infrared, and ultraviolet–visible spectroscopy characterised the synthesised Ag nanomaterials. The X-ray diffraction pattern obtained from the collected samples confirms the presence of a face-centred cubic structure and a significant level of crystallinity. The studied materials had a spherical morphology, as determined by transmission electron microscopy analysis. The particle size was measured to be 22 nm. FT-IR analysis validates the presence of biomolecules in the leaf extract, which is accountable for the reduction of Ag+ ions and subsequent stabilisation of Ag nanoparticles. Without chemical agents, the reduction of Ag ions to Ag was confirmed using UV–Vis spectroscopy. This analytical technique revealed a peak at 450 nm, indicating surface plasmon resonance. Photogenerated electron carriers can be inferred from a distinct and diverse set of photoluminescence spectra. The study also includes an analysis of the photocatalytic effectiveness of the synthesised silver nanoparticles, specifically in the breakdown of methylene blue (MB) dye. The efficacy of the silver nanoparticle (Ag NP) photocatalyst was assessed by examining the degradation process of a methylene blue dye solution in an aqueous medium under direct sunlight exposure. The experiment also evaluated the impact of catalyst dosage and dye concentration on the efficient degradation of MB dye. The investigation findings indicate that the optimal catalyst dosage and dye concentration were determined to be 0.015 mg/mL and 10 µM, respectively. Notably, the photocatalytic degradation process exhibited remarkable efficacy, with a peak efficiency of 94% after 120 min under direct solar irradiation. The experimental results suggest that the synthesised particles demonstrate a disintegration rate of 96% over 120 min when exposed to visible light. The utilisation of bio-processed silver nanoparticles has exhibited the achievement of phase purity during the manufacturing process, as well as an enhancement in catalytic efficacy. It implies that the synthesised technique offers a more advantageous option for producing nanoparticles on a large scale, potentially applicable in wastewater treatment at a broad level.

Sediment production process and hydraulic characteristics of ephemeral gully erosion in granite hilly area

Ephemeral gully (EG) erosion represents the early stage of large-scale gully (locally named as “Benggang”) development on Ultisols in the granite hilly area. However, the EG erosion process and the mechanism underlying sediment production have not been fully elucidated. In this study, a series of field scouring experiments were conducted under different flow discharge levels (10, 15, 20, 25, and 30 L·min−1), and the primary EGs in three typical soil layers with different weathering degrees (red soil layer (RL), transition layer (TL), and sandy layer (SL)) was dynamically monitored. The results indicated that the ratio of width to depth of the EGs rapidly decreased as the flow discharge increased. At 30 L·min−1, the average sediment yield and transport rate (Sr) of the SL were 4.85 and 5.39 times, greater than those of the RL, respectively. The sediment particles were concentrated within the 1–2 mm particle size range, accounting for over 35 %. In addition, the mean weight diameter of the sediment particles in the RL was the largest. The sediment distribution characteristics did not respond to flow changes but were affected by EG morphological changes. With increasing flow discharge, the flow shear stress and stream power increased. Further analysis revealed that the coupling effect of flow hydraulic characteristics and EG morphological evolution drove the EG erosion sediment production process, and the Sr of the SL was highly sensitive to flow discharge changes. The soil disintegration rate was an internal factor that directly affected soil loss in the EGs, with a path coefficient of 0.71. The bulk density, organic matter content, and sand content were all indirect influencing factors. The RL exhibited greater anti-erodibility than the other layers and could serve as an effective protective layerfor granite hilly areas. These findings provide a theoretical basis for improving soil loss management systems.

Enhancing short-chain fatty acids production via acidogenic fermentation of municipal sewage sludge: Effect of sludge characteristics and peroxydisulfate pre-oxidation.

This study first employed a combined pretreatment of low-dose peroxy-disulfate (PDS) and initial pH 10 to promote short-chain fatty acids (SCFAs) production via acidogenic fermentation using different types of sewage sludge as substrates. The experimental results showed that the yield of maximal SCFAs and acetate proportion after the combined pretreatment were 1513.82±28.25mg chemical oxygen demand (COD)/L and 53.64%, and promoted by 1.28 and 1.56 times higher, respectively, compared to the sole initial pH 10 pretreatment. Furthermore, in terms of the disintegration degree of sewage sludge, it increased by more than 18% with the combined pretreatment compared to the pretreatment of sole initial pH 10. Waste-activated sludge (WAS) from A2/O and Bardenpho processes were more biodegradable, explained by the 1.47- and 1.35-times higher disintegration rate than those from oxidation ditch and they favored acetate dominant fermentation. Correlation analysis revealed a strong correlation (p ≤ 0.01) between SCFAs production and soluble COD, total proteins, proteins in soluble-extracellular polymeric substances (SEPS), total polysaccharides, and polysaccharides in SEPS. Mechanism explorations showed that preoxidation with PDS enhanced the solubilization and biodegradability of complex substrates, and altered the microbial community structure during the fermentation process. Firmicutes and Tetrasphaera were proven to play a key role in improving SCFA production, especially in promoting acetate production by converting additional SCFAs into acetate. Additionally, the addition of PDS greatly promoted sulfur and iron-related metabolic activities. Finally, the combined pretreatment was estimated to be a cost-effective solution for reutilizing and treating Fe-sludge.