Search Results (2,305)

Lotus stems contain cellulose, which can be utilized as a base material for producing green products, specifically degradable plastics. This research investigates the effect of polylactic acid (PLA) blends on cellulose degradable plastics from the lotus stem (Nelumbo nucifera). The mechanical characteristics are as follows: tensile strength of 0.7703–3.3212 MPa, elongation of 0.58–1.16%, Young’s modulus of 78.7894–364.6118 MPa. Compound analysis showed the presence of O-H, C-C, and C=O groups, and the presence of microbial activity in the soil can also lead to the degradation of these groups due to their hydrophilic nature, which allows them to bind water. Thermal analysis within a temperature range of 413.24 °C to 519.80 °C, shows that significant weight loss begins with the formation of crystalline structures. The degradable plastic exhibiting the lowest degree of swelling consists of 1 g of cellulose and 8 g of PLA, resulting in a swelling value of 6.25%. The degradable plastic is anticipated to decompose most rapidly after 52 days, utilizing 2 g of PLA and 7 g of cellulose. This complies with standard requirement, which sets a maximum degradation period of 180 days for polymers. Full article

The effects of biochar on Bermuda grass growth and mechanical properties of vegetated soil were investigated in this study. Six groups of soil column tests were conducted, including two degrees of compaction (DOC) (70% and 90%) and two types of biochar content (5% and 10% by soil dry weight), with two groups of bare soil serving as a reference (soil used in the test was classified as silty sand with gravel, i.e., SM). It was found that biochar increased the effective cohesion by up to 70% and slightly enhanced the effective internal friction angle while mitigating the detrimental effects of wetting–drying cycles, with the effective cohesion and friction angle retaining up to 73% and 99% of their initial values, respectively. Root biomass initially increased and then decreased as biochar content increased, particularly at a low degree of compaction of soil (i.e., 70% DOC was two times that of 90% DOC). The effective cohesion of intact biochar–root–soil initially increased up to 23% (at the biochar content of 5%, 90% DOC) and then decreased as biochar content increased, regardless of DOC. At the optimal biochar content (5%), the effective cohesion and internal friction angle of rooted soil were 1.4 and 1.1 times greater at low DOC (70%). For the remolded biochar–root–soil composite, at a high degree of compaction (90% DOC), the effective cohesion increased with the increase in root and biochar content. For a given root content, the shear strength of the remolded biochar–root–soil mixture was higher than that of intact biochar–root–soil (i.e., the shear strength of intact soil at 5% of biochar content was 87% of remolded soil), suggesting that the remolded soil mixture overestimated the biochar–root–soil strength. Generally, the present study demonstrates that a 5% biochar addition is optimal for enhancing plant root growth and soil strength, particularly under low compaction. Biochar significantly improves the mechanical performance of root–soil composites and mitigates the degradation of soil strength under wetting–drying cycles. Full article

The effects of storage temperature (4 °C, −1 °C, and −4 °C) after the very fast chilling (VFC) treatment on the glycolysis in lamb were investigated. The meat tenderness, glycolytic rates, activity, phosphorylation, and acetylation levels of glycolytic enzymes in meat stored at different temperatures were measured. It was shown that there was no significant difference in the degradation degree of desmin and troponin T in meat at different storage temperatures after VFC treatment (p < 0.05). The decrease rate of pH and ATP in meat was the same under different storage temperatures. The promoted phosphorylation and acetylation levels of phosphofructokinase (PFKM) and phosphoglycerate kinase (PGK) and inhibited acetylation level of aldolase (ALDOA) in the samples stored at different temperatures maintained the same glycolytic rate. In conclusion, chilling treatment is the key step in improving meat tenderness rather than storage temperature, which is achieved by the increased phosphorylation of ALDOA, PFKM, and PGK and decreased acetylation of ALDOA. It indicated that the chilling rate promoted the improvement of meat quality mainly by delaying glycolysis compared to the storage temperature. Full article

Tidal turbines represent a promising renewable energy source, generating power from ocean currents. However, due to tidal range variations, they sometimes become partially exposed to the free surface. When this occurs, the turbine experiences reduced power generation and unsteady torque caused by the asymmetric flow. Such conditions can lead to long-term degradation of turbine performance and reliability. From this perspective, a key question arises regarding how significantly power generation differs when turbines are exposed to the free surface. This study was conducted with the objective of quantitatively evaluating the differences in power generation and torque acting on the turbine due to free-surface exposure, in order to address this question. Numerical simulations considering free-surface exposure effects were developed to quantitatively assess these phenomena through Computational Fluid Dynamics (CFD). Additionally, this numerical model was validated by comparison against experimental data and verified by convergence tests. The results revealed that the tidal turbine exhibited power generation differences ranging from a maximum of 45% to a minimum of 0.44%, depending on the degree of free-surface exposure. These findings are expected to serve as valuable indicators for power generation when operating tidal turbines. Full article

Rotor equipment material samples with varying degrees of degradation during long-term operation are characterized by lower (up to 17%) corrosion and hydrogen resistance compared to the initial state. The scheme of redistribution of carbides in structural components in the initial state and after long-term operation is presented. The schemes of the turning rotor shaft are visualized, while taking the microstructure features into account. During long-term service, the properties of steels are affected by changes in the parameters of structural components caused by the action of a hydrogen-containing environment. Based on the experimental data, the regression equation and approximation probability R² value describing the change in the electrochemical parameters of 38KhN3MFA rotor steel samples after 200, 225, 250, and 350 thousand hours of operation were obtained. During machining, an increase in hydrogen content was recorded in the chips, especially from degraded areas of the rotor shaft (up to 7.94 ppm), while in undegraded zones, it ranged from 2.1 to 4.4 ppm. A higher hydrogen concentration was correlated with increased surface roughness. The use of LCLs improved surface quality by 1.5 times compared to LCL_p. Dispersion caused by degradation contributed to hydrogen accumulation and changed the nature of material destruction. After repair, the rotors demonstrated stable operation for over 25 thousand hours, with no reappearance of critical defects observed during scheduled inspections. Full article

In the coal pillar dam of underground water reservoirs, groundwater exerts a certain degree of dissolution and erosion on the coal body, inducing the development of internal cracks and the deterioration of its mechanical properties. To this end, coal samples with varying moisture contents were prepared through a water-absorption experiment; the changes in the mechanical strength of coal samples with five moisture contents (0%, 3.62%, 4.93%, 5.52%, and 6.11%) were tested via uniaxial compression tests, uniaxial tension tests, and variable-angle shear tests; and the degradation in mechanical performance in water-immersed coal samples and their sensitivity to moisture content were evaluated. The experiment yielded the following results: (1) The moisture content of coal samples increases with the increase in immersion time, and the water-absorption rate first rises, then decelerates and gradually becomes stable. When the immersion time is about 72 h, the coal sample reaches a saturated state. (2) As the samples transition from a dried state to full saturation, the uniaxial compressive strength of coal samples decreases from 29.17 MPa to 7.38 MPa, and the uniaxial tensile strength decreases from 0.78 MPa to 0.33 MPa. The peak shear strength also decreases with an increase in immersion time and the increase in shear angle, while the deterioration degree gradually increases with the increase in immersion time and tends to be stable. (3) Based on a sensitivity analysis, the mechanical performance evolution of water-immersed coal samples can be divided into four stages based on the moisture content: tensile-dominated stage, shear-dominated stage, compression catching-up stage, and compression-dominated stage. Full article

Jerusalem artichoke (Helianthus tuberosus L.) is a valuable source of inulin and fructooligosaccharides—compounds with well-documented prebiotic and functional food properties. However, its high moisture content significantly limits storage stability. This study aimed to assess the effects of drying method and process temperature on the drying kinetics and selected physicochemical properties of Jerusalem artichoke. Convective drying (AD) and combined convective–microwave drying (AMD), using a microwave power of 100 W, were employed. Drying was conducted at air temperatures of 40 °C, 60 °C, and 80 °C. Among the mathematical models evaluated, the Page model provided the best fit to the experimental drying data for both methods. Samples dried at 80 °C using the AMD technique exhibited the most pronounced changes in color, significant polyphenol losses, and a substantial reduction in antioxidant capacity compared to the fresh material. The lowest polyphenol degradation and the highest retention were observed in products dried at 40 °C using both AD and AMD methods. Notably, the AMD method significantly reduced drying time and improved the grindability of the dried Jerusalem artichoke samples. Although AMD contributed to certain quality deterioration, it also promoted a higher degree of particle size reduction. However, this increased degree of particle size reduction had only a limited effect on the extraction efficiency of fructooligosaccharides and inulin. The results of the present study suggest that AMD may serve as a competitive alternative to AD for drying Jerusalem artichoke, particularly when processing time and grindability are critical considerations. Full article

Thermogravimetric analysis (TGA) is a key technique for evaluating the kinetics and thermodynamics of thermal degradation, providing essential data for material assessment and system design. When coupled with Fourier-transform infrared (FT-IR) spectroscopy or mass spectroscopy (MS), it enables the identification of evolved gases and correlates mass loss with specific chemical species, offering detailed insight into decomposition mechanisms. In this study, TGA was coupled with FT-IR and MS to investigate the thermal degradation behavior of Bakelite, with the aim of evaluating its kinetic and thermodynamic parameters under non-isothermal conditions, identifying evolved volatile compounds, and elucidating the degradation process. The results showed that higher heating rates led to increased decomposition temperatures and broader dTG peaks due to thermal lag effects. The degradation proceeded in multiple stages between 220 °C and 860 °C, ultimately yielding a carbonaceous residue. The activation energy increased with conversion, particularly beyond 0.5, indicating a greater energy requirement as degradation progressed. Peak values at conversion degrees of 0.8–0.9 suggested enhanced thermal stability or changes in the dominant reaction mechanism. Detailed kinetic analysis revealed complex decomposition pathways with variable activation energies and a pronounced kinetic compensation effect. Thermodynamic analysis confirmed the endothermic nature of the process, with increasing energy demand and non-spontaneous degradation of the resulting char. TGA/FT-IR and TGA/MS analyses identified the release of several compounds, including CO₂, water, formaldehyde, and phenolic derivatives, at distinct stages. This comprehensive understanding of Bakelite’s thermal behavior supports its optimization for high-temperature applications, enhances material reliability and safety, and contributes to sustainable processing and recycling strategies. Full article

Various low-light image enhancement techniques inevitably introduce noise to varying degrees while improving visibility, leading to a decline in image quality that adversely affects downstream vision tasks. Existing post-processing denoising methods often produce overly smooth results lacking in detail, presenting the challenge of balancing noise suppression and detail preservation. To address this, this paper proposes a conditional diffusion denoising framework based on multi-feature fusion. The framework utilizes a diffusion model to learn the conditional distribution between underexposed and normally exposed images. Complementary features are extracted in parallel through four dedicated branches. These multi-source features are then concatenated and fused to enrich semantic information. Subsequently, redundant information is compressed via 1 × 1 convolutional layers, mitigating the issue of information degradation commonly encountered with U-Net skip connections during multi-scale feature fusion. Experimental results demonstrate the method’s applicability across diverse scenarios and illumination conditions. It outperforms both traditional methods and mainstream deep learning models in qualitative and quantitative evaluations, particularly in terms of perceptual quality. This research provides significant technical support for subsequent image restoration and denoising within low-light enhancement pipelines. Full article

The acid number evaluates the degree of deterioration of lubricating oil. Existing methods for evaluating the performance degradation of lubricating oils are mostly based on the detection of traditional physical and chemical indicators, which often only reflect a single dimension of the degradation process, thus affecting the accuracy and repeatability of the results. Integrating multi-dimensional information can more comprehensively reflect the essence of degradation, which can improve the accuracy and reliability of the evaluation results. Mid-infrared spectroscopy is an effective means of monitoring the acid number. In this study, a combination of infrared spectroscopy quantitative analysis and chemometrics was used. The oil sample data was divided into training set and validation set by the Kennard–Stone method. In the experiment, a Fourier transform infrared spectrometer equipped with an attenuated total reflection accessory (ATR-FTIR) was used to collect spectral data of the samples in the wavenumber range of 1750–1700 cm⁻¹ (this range corresponds to the characteristic absorption of carboxyl groups and is directly related to the acid number). Meanwhile, a G20S automatic potentiometric titrator was used to determine the acid number as a reference value in accordance with GB/T 7304. The study compared various preprocessing methods. A regression prediction model between the spectra and acid number was established using partial least squares regression (PLSR) within the selected wavenumber range, with the root mean square error of cross-validation (RMSECV), root mean square error of prediction (RMSEP), and coefficient of determination (R) as evaluation indicators. The experimental results showed that the PLSR model established after preprocessing with second derivative combined with seven-point smoothing exhibited the optimal performance, with an RMSECV of 0.00505, an RMSEP of 0.14%, and an R of 0.9820. Compared with the traditional titration method, this prediction method is more suitable for real-time monitoring of production lines or rapid on-site screening of equipment. It can in a timely manner warn of the deterioration trend of lubricating oil, reduce the risk of equipment wear caused by oil failure, and provide efficient technical support for lubricating oil life management. Full article

Pectin is a renewable polysaccharide valued for its gelling, stabilising, and encapsulating properties, with broad applications in food, pharmaceutical, and industrial sectors. However, extraction conditions critically affect its yield, structural integrity, and functional performance. Despite citrus peel being a major source of pectin, large amounts remain underutilised as waste. This study systematically investigates how different acid types influence the extraction efficiency and structural quality of pectin derived from citrus peel. Dried citrus peel powder was extracted using four acids—sulphuric, hydrochloric, acetic, and citric—under controlled conditions at 80 °C. Extractions were performed at a fixed time of 90 min for all acids, with additional time trials for sulphuric acid. Extracted pectins were evaluated for gravimetric yield, colour, solubility, degree of esterification (DE) by titration and FTIR, and structural features using FTIR and ¹H NMR spectroscopy. Results showed that sulphuric and hydrochloric acids yielded the highest pectin recoveries (30–35% and 20–25%, respectively) but caused significant degradation, evident from dark colour, broad FTIR peaks, low DE (<10%), and poor solubility. In contrast, acetic and citric acid extractions resulted in moderate yields (8–15%) but preserved the pectin backbone and maintained higher DE (>30%) compared to the mineral acid-extracted samples and the commercial low methoxyl (LM) standard, as confirmed by clear FTIR and NMR profiles. These findings demonstrate the trade-off between extraction yield and structural integrity, underscoring the potential of mild organic acids to produce high-quality pectin suitable for value-added applications. Optimising acid type and extraction conditions can support sustainable waste valorisation and expand the industrial use of citrus-derived pectin. Full article

The control of many industrial processes, such as superheated steam temperature control, exhibits poor robustness and degraded accuracy in the presence of model parameter uncertainties. This paper addresses this issue by developing a novel interval power integration-based nonlinear suppression scheme for a class of uncertain nonlinear systems with unknown but bounded parameters. The efficacy of this approach is specifically demonstrated for the superheated steam temperature control in thermal power plants. By integrating Lyapunov stability theory and homogeneous system theory, this method extends the traditional homogeneous degree theory to the interval domain, establishes interval boundary conditions for time-varying parameters, and constructs a Lyapunov function with interval numbers to recursively design the controller. Furthermore, the interval monotonic homogeneous degree and an admissibility index are introduced to ensure system stability under parameter uncertainties. The effectiveness of the proposed method is verified through numerical simulations of superheated steam temperature control. Simulation results demonstrate that the method effectively suppresses nonlinearities and achieves robust asymptotic stability, even when model parameters vary within bounded intervals. In the varying-exponent scenario, the proposed controller achieved an Integral of Absolute Error (IAE) of 70.78 and a convergence time of 37s for the superheated steam temperature control. This represents a performance improvement of 42.79% in IAE and 53.16% in convergence time compared to a conventional PID controller, offering a promising solution for complex thermal processes with inherent uncertainties. Full article

The article presents the results of the first successful synthesis of degradable microbial copolymers of 3-hydroxybutyrate and 3-hydroxyvalerate [P(3HB-co-3HV)] by the wild-type strain C. necator B-10646 using waste fish oil (WFO) obtained from the heads of Sprattus sprattus balticus. Samples of copolymers with 3HV monomer contents from 11.9 to 59.7 mol.% were synthesized with fractional and controlled feeding of potassium valerate, a precursor of 3HV monomers, into the bacterial culture. Samples synthesized on WFO with different contents of 3HV monomers had a reduced degree of crystallinity (36.5% and below), and close average molecular weight (390–573 kDa), with polydispersity of 2.6–3.0, and retained thermal stability, with a gap between the melting point and the thermal degradation temperature of over 100 °C. The thermal behavior of the samples, including the kinetics of exothermic crystallization and spherulite formation, was studied. Demonstrating the possibility of using WFO for the effective synthesis of P(3HB-co-3HV) with macroinclusions of 3HV monomers without deterioration of their properties is important for expanding the raw material base, reducing costs and increasing the availability of these promising bioplastics. Full article

Polyethylenimine (PEI) is a cationic polymer with a high density of amine groups suitable for strong electrostatic interactions with biological molecules to preserve their bioactivities during encapsulation and after delivery for biomedical applications. This review provides a comprehensive overview of PEI as a drug and gene carrier, describing its polymerization methods in both linear and branched forms while highlighting the processing methods to manufacture PEIs into drug carriers, such as nanoparticles, coatings, nanofibers, hydrogels, and films. These various PEI carriers enable applications in non-viral gene and small molecule drug deliveries. The structure–property relationships of PEI carriers are discussed with emphasis on how molecular weights, branching degrees, and surface modifications of PEI carriers impact biocompatibility, transfection efficiency, and cellular interactions. While PEI offers remarkable potential for drug and gene delivery, its clinical translation remains limited by challenges, including cytotoxicity, non-degradability, and serum instability. Our aim is to provide an understanding of PEI and the structure–property relationships of its carrier forms to inform future research directions that may enable safe and effective clinical use of PEI carriers for drug and gene delivery. Full article

Subcooling-based ice slurry production faces challenges in terms of energy efficiency and operational stability, which limit its applications for large-scale cold energy storage. A thermodynamic model is established to investigate the effects of key control parameters, including evaporation temperature, condensation temperature, subcooling degree, water flow rate, type of refrigerant, and adiabatic compression efficiency. The results show that using the refrigerant R161 achieves the highest energy efficiency, indicating that R161 is the optimal refrigerant in this research. When the evaporation and condensation temperatures are −10 °C and 30 °C, respectively, the system achieves the maximum comprehensive performance coefficient of 2.43. Moreover, under a flow velocity of 0.8 m/s and a temperature of 0.5 °C, the system achieves a peak ice production rate of 45.28 kg/h. A high water temperature and high flow velocity would significantly degrade the system’s ice production capacity. This research provides useful guidance for the design, optimization, and application of ice slurry-based cold energy storage systems. Full article