The architecture of hydrogel composites results in not only synergistic property enhancement but also superior functionality. The reaction−diffusion (RD) process is acommon phenomenon throughout nature which induced ordered structure on a length scale from microscopic to macroscopic. Different from commonly used inorganic salts or oppositely charged nanoparticles for the RD process, a modified RD process was used for layered chitosan hydrogel (L-CH) and layered magnetic chitosan hydrogel (L-MCH). During the modified RD process reported in this paper, the protonated chitosan (CS-NH3+) with iron ions (Fe3+ and Fe2+) was used as an inner-reactant and hydroxide ion (-OH−) was used as an out-reactant. The protonated chitosan (CS-NH3+) not only played the role of an inner-reactant but also the reaction medium which controlled the diffusion behavior of the out-reactant (-OH−). A series of ordered layers were constructed and the ordered layers were parallel with the longitudinal axis. The laye... [more]

Flashing-induced instability (FII) has a significant impact on the safe operation of a natural circulation circuit, a phenomenon frequently encountered in the cooling systems of advanced light water reactors. While one-dimensional system codes are commonly used for the engineering design and safety analysis of FII, there is a strong academic interest in understanding the underlying physical mechanisms. To address this, high-resolution computational fluid dynamics (CFD) simulations serve as a valuable tool. However, the current state of CFD modeling for two-phase flows with phase change, which are particularly highly transient fluctuating flashing flows, is still in its early stages of development. In this study, we establish a CFD model that focuses on interphase heat transfer to analyze the phase change during FII. By incorporating experimental data from the literature, we investigate the transient flow field and thermodynamic behavior in the riser of the GENEVA test facility. The stu... [more]

Due to the complexity of mold flow channel parameters, they have a significant impact on medical microtubule forming quality during the gas-assisted extrusion process. In this paper, the influence mechanism of mold flow channel parameters on medical microtubule forming quality is investigated. First, the multiphase flow model of the medical microtubule gas-assisted extrusion process is established. Then, the numerical solution of medical microtubule extrusion is presented based on Polyflow finite element software. Further, the medical microtubule size, morphology, velocity, pressure, and first normal stress difference under different mold flow channel parameters are compared and analyzed. Finally, the experimental platform for gas-assisted extrusion is built, and the correctness of the numerical simulation is verified by the extrusion experiment. The simulation and experimental results show that under the 15−5 condition, the inner radius, outer radius, and wall thickness of the microtu... [more]

The diesel engine, as the main power source of equipment, faces practical problems in the maintenance process, such as difficulty in fault location and a lack of preventive maintenance techniques. Currently, breakdown maintenance and cyclical preventive maintenance are the main means of maintenance support after a diesel engine failure, but these methods require professional maintenance personnel to carry out manual fault diagnosis, which is time-consuming. Prognostics and health management (PHM), as a new technology in the field of equipment maintenance support, has significant advantages in improving equipment reliability and safety, enhancing equipment maintenance support capability, and reducing maintenance support costs. In view of this, when introducing PHM into diesel engine maintenance support, the research progress and development trend of the key technologies of PHM for diesel engines are carried out with the objective of achieving precise maintenance and scientific managemen... [more]

Heavy-metal pollution has attracted wide attention in recent years. The problem of heavy-metal pollution in the vicinity of the Dabaoshan mine, the largest polymetallic mine in South China, has attracted widespread attention. In this study, 38 samples of rice and paddy soil near the Dabaoshan mine were collected. The physical and chemical properties of the soil, including Cu, Cd, Zn, Pb, and Ni levels in the soil and rice, were analyzed. The heavy-metal baseline in paddy soil was analyzed by a normal Q−Q plot. The bioaccumulation factor of the rice was calculated. The non-carcinogenic risk of heavy metals was evaluated by calculating the hazard quotient (HQ). Threshold values of Cu, Cd, Zn, Pb, and Ni were 35.01, 0.51, 70.94, 59.78, and 16.34 mg/kg, respectively. The threshold values of Cu, Zn, and Pb were higher than the background value and lower than the secondary value of China’s soil environmental quality standard. The threshold value of Cd was higher than both the background valu... [more]

This study aimed to produce biochar with an energy value in the range of sub-bituminous carbon by investigating the effect of oxidative and non-oxidative torrefaction on the torrefaction yield and fuel properties of wheat straw. Three independent variables were considered at different levels: temperature (230, 255, 280, 305 °C), residence time (20, 40, 60 min), and reaction atmosphere (0, 3, 6 vol% O2; N2 balance); and three dependent variables: mass yield, energy yield, and percentage increase in higher heating value (HHV). The results showed that it is possible to produce a sub-bituminous carbon type C biochar using oxidative torrefaction, significantly reducing time and temperature compared with non-oxidative torrefaction. The optimum torrefaction conditions were 287 °C−20 min−6.0% O2, which increased the HHV of wheat straw from 13.86 to 19.41 MJ kg−1. The mass and energy yields were 44.11 and 61.78%, respectively. The physicochemical and fuel properties of the obtained biochar were... [more]

A similarity criterion suitable for studying the vibration characteristics of converter transformers is proposed based on comprehensive consideration of geometric dimensions, electric field, magnetic field, force field, sound field, and coupling field interface interactions. By comparing the magnetic field, stress, displacement, sound field distribution, and vibration characteristics of the scale model of the converter transformer with the initial model, the reliability of the similarity criterion was determined. Based on the vibration similarity criterion of the converter transformer, a prototype of the proportional model was designed and manufactured, and vibration signals under no-load and load conditions were tested. These signals correspond to the vibration signals of the iron core and winding in the finite element model, respectively. Through comparative analysis, the reliability of the prototype and the vibration similarity model of the converter transformer has been proven, whi... [more]

There is a growing demand for more flexibility in manufacturing to counter the volatility and unpredictability of the markets and provide more individualization for customers. However, the design and implementation of flexibility within manufacturing systems are costly and only economically viable if applicable to actual demand fluctuations. To this end, companies are considering additive manufacturing (AM) to make production more flexible. This paper develops a conceptual model for the impact quantification of AM on volume and mix flexibility within production systems in the early stages of the factory-planning process. Together with the model, an application guideline is presented to help planners with the flexibility quantification and the factory design process. Following the development of the model and guideline, a case study is presented to indicate the potential impact additive technologies can have on manufacturing flexibility Within the case study, various scenarios with diff... [more]

A cylindrical plunge grinding process was modeled to investigate nonlinear regenerative chatter vibration. The rotating workpiece was a slender Euler−Bernoulli beam, and the grinding wheel was a rigid body moving towards the workpiece at a very low feed speed. A numerical method was proposed to provide the critical boundaries for chatter-free grinding. It was demonstrated that the intersection set surrounded by these critical boundaries was the chatter-free region for the considered parameters. When these parameters were outside of the chatter-free region, the stable grinding process underwent a supercritical Hopf bifurcation, resulting in the loss of the chatter-free behavior and the emergence of periodic chatter motions. Then, the periodic motions of both the grinding wheel and the workpiece were predicted analytically using the method of multiple scales, showing the effect of the regenerative force on the grinding process. We demonstrated that the analytical prediction was valid sin... [more]

This study evaluated the effects of dielectric barrier discharge (DBD) plasma technology on some physicochemical and structural properties of corn starch. Amylose content, solubility, water absorption index, turbidity, structural relationships, and surface morphology were measured at 100, 200, and 300 Hz excitation frequencies and at 10 and 20 min exposure times. The plasma treatment at 200 Hz and 20 min promoted the most significant modifications in amylose content, solubility, the water absorption index, and surface morphology. Turbidity did not change significantly. The surface of the granule became smoother with the presence of pores. Slight changes were observed in the ordered structure of starch. Plasma changed several physicochemical properties, significantly decreasing the amylose to amylopectin ratio. Plasma treatment at 200 Hz is recommended to increase the amylopectin content in starches.

A special study on the interaction mechanism between flow and soil is of great significance for revealing the macro breaching mechanism of barrier dams. To study the scouring characteristics of wide-graded sediment under different flow conditions, flume scour tests were conducted regarding the grading curve of dam material and the discharge process of the Tangjiashan barrier dam. The results show that: (1) The scouring process of narrow-graded or uniform sediments is the formation and movement of the sand wave, while the scouring mode of wide-graded sediment is mainly the formation, expansion, and movement of the scouring pit. (2) Under the condition of weak unsteady flow, the surrounding and shielding effect of coarse particles on fine particles is obvious, and the erosion resistance of the material is strong. However, under the condition of strong unsteady flow, the erosion resistance is weak. (3) The erosion of wide-graded sediment is mainly caused by slope angle collapse at the ini... [more]

During the production of deep oil and gas, scaling, waxing, hydrate ice plugging and other problems easily occur. To solve these problems, reducing the temperature loss of oil pipelines is a feasible method. In order to protect the outer wall coating from being damaged and losing its thermal insulation performance, this paper proposes a developed technology for a novel inner wall coating-insulated oil pipeline. A new temperature-resistant and heat-insulating material aerogel was optimized and developed, and it has an extremely low thermal conductivity of less than 0.055 W/m·K. The influence of different coating processes on the thermal insulation coefficient was analyzed, and a novel inner wall coating-insulated oil pipeline was developed. A testing and evaluation platform for its thermal insulation effect was built, and a finite element model was established to analyze the temperature field distribution. When the thickness of the inner coating was 0.5 mm, the thermal insulation effect... [more]

This article aims to enhance technological advancements in the classification of polyethylene terephthalate (PET) bottle plastic, positively impacting sustainable development and providing effective solutions for collection centers (CC) in Mexico. Three experimental designs and machine learning tools for data processing were developed. The experiments considered three factors: bottle size, liquid volume, and bottle labels. The first experiment focused on determining the sensor distance from post-consumer PET bottles. The second experiment aimed to evaluate the sensor’s detection ability with varying liquid levels, while the third experiment assessed its detection capability for bottle labels. A digital lux meter integrated with a microcontroller was developed to monitor illuminance in post-consumer PET bottles containing liquid as they moved through a conveyor belt at an average rate of three bottles per second. The implemented methodology successfully detected liquids inside transpare... [more]

The safety of underground engineering projects is significantly influenced by groundwater. One of the key complexities is identifying the primary seepage paths within underground rock formations, understanding the patterns of seepage, and determining the effects of fracture parameters on the fluid movement inside the rock mass. To address these issues, a probabilistic model is constructed for random fractures using the finite element method, reflecting the random nature of fracture distributions in the real world. This model allows for an in-depth examination of the distribution of pore water pressure and Darcy velocity field, revealing the permeability trends in fractured rock masses. A variety of fracture models were devised to understand the relationship between factors such as fracture density, length, length power law, angle, dispersion coefficient, aperture, and power law, and how they affect the overall permeability of rock masses. The study suggests that, in the context of disc... [more]

The study investigated the effect of on-farm rest period (RP) on carcass composition, meat quality, and stress indicators of culled sows. The study was conducted on 84 Large White × Landrace culled sows, which were divided into seven groups (n = 12) with respect to the duration of the on-farm rest period: no rest period (N-RP) group and 1 to 6 weeks of on-farm rest period (1−6 RP). After completion of the on-farm RP, each group of culled sows was slaughtered and the carcass and meat quality traits were determined. Sows from 6-RP had a significantly higher dressing percentage and backfat thickness and, together with sows from 5-RP, a higher shoulder weight. The highest shoulder percentage was found in the 3-RP and 4-RP groups, while 1-RP had the highest percentage for the belly−rib part. At the same time, RP influenced the final pH values (pH24 SM and pH24 LL) measured in the longissimus thoracis et lumborum (LT) and in the musculus semimembranosus (SM), as well as drip loss, thawing lo... [more]

In order to reduce carbon emission and energy consumption in the process of raw material distribution, the workshop material distribution management model was established based on the business compass model; it can help guide enterprises to manage workshop production. Based on the raw material distribution equipment, a path calculation model considering the carbon emission and energy consumption in the process of raw material distribution was established. The dung beetle optimizer was selected for the optimization calculation. The dung beetle optimizer has the characteristics of fast convergence and high solution accuracy. The material distribution of an engine assembly workshop was taken as an example; the results showed that the optimized scheduling model could effectively optimize the material distribution route and reduce energy consumption and carbon emission in the distribution process on the basis of meeting the distribution demand.

According to the characteristics of “Three Soft” outburst coal seams in the Henan area with large gas content, poor air permeability, and extremely difficult extraction, the hydraulic fracturing and punching technology of soft coal with packer tool string sealing method was studied. Xinzheng Coal Electric Power Company is a coal and gas outburst mine, and the second coal seam is a typical soft outburst coal seam. In 14201, upper bottom drainage roadway, which has a broken top plate, a test of penetration hydraulic pressure thrust-enhanced permeability technology based on packer sealing mode was carried out. The average concentration in the press-punching area was 4.8 times that in the non-press-punching area (to be tested), and the average pure volume of 100 holes in the test area was 42 times that in the untested area. During hydraulic pressure punching in the test area, affected by fracturing disturbance, the concentration and purity of the test area and the adjacent test area signif... [more]

Conglomerate reservoirs are usually formed in sag slope belts, which have the characteristics of near-source rapid deposition, rapid sedimentary facies change, and distinct reservoir heterogeneity. Therefore, it is difficult to carry out treatments of stimulation because of insufficient understanding of the propagation mechanism of the unique “gravel-bypassing” and “gravel-penetrating” characteristics of fracture morphologies in Mahu conglomerate reservoirs. In order to study the law of hydraulic fracture propagation in conglomerate reservoirs, based on Brazilian splitting test results for conglomerates with different gravel particle sizes and different cementation degrees, true tri-axial fracturing experiments conducted in the laboratory were performed to conduct experimental research on natural conglomerate outcrops and analyze the effects of gravel size, fracturing fluid viscosity, and pumping rate on hydraulic fracture propagation morphology. The results show that: (1) the gravel c... [more]

With the rapid popularization and development of renewable energy, solar photovoltaic power generation systems have become an important energy choice. Convolutional neural network (CNN) models have been widely used in photovoltaic power forecasting, with research focused on problems such as long training times, forecasting accuracy and insufficient speed, etc. Using the advantages of swarm intelligence algorithms such as global optimization, strong adaptability and fast convergence, the improved Aquila optimization algorithm (AO) is used to optimize the structure of neural networks, and the optimal solution is chosen as the structure of neural networks used for subsequent prediction. However, its performance in processing sequence data with time characteristics is not good, so this paper introduces a Long Short-Term Memory (LSTM) neural network which has obvious advantages in time-series analysis. The Cauchy variational strategy is used to improve the model, and then the improved Aquil... [more]

As the global market becomes increasingly competitive and demanding, companies face the challenge of responding swiftly and efficiently to customer needs. To maintain a competitive advantage, organisations must optimise the usage of their assets. This study focuses on the critical role of maintenance management and presents a novel, cost-effective, and easily applicable model that integrates Industry 4.0 (I4.0) and Total Productive Maintenance (TPM) principles to enhance production processes. The proposed model incorporates a real-time monitoring system equipped with sensors, a gateway, and Internet of Things (IoT) services. These components enable data acquisition, transmission, storage, and visualisation through both mobile and fixed devices. The model’s effectiveness was validated through its implementation on a conveyor belt in a feed mill. The availability of the conveyor belt was around 89.5% before TPM implementation. After the implementation of TPM, it was possible to observe t... [more]

seeds are reported to treat a variety of diseases; they contain multiple antidiabetic constituents and are widely used as anti-hyperglycemic, antibacterial, as well as anti-hyperlipidemic agents. The present work aimed to propose tablet formulations containing extracts of S. securidaca seeds in an attempt to obtain antibacterial and anti-hyperglycemic formulations with a more efficient oral hypoglycemic impact, limited side effects, and higher patient compliance for the first time, resulting in multiple benefits. Tablet formulations were created by encapsulating granules from S. securidaca seed extracts with varying concentrations of sodium starch glycolate as a super-disintegrant (0−3%). The final formulations were examined for weight variation, solubility, hardness, water content, disintegration time, friability, drug content (trigonelline and diosgenin), and in vitro drug release. The S. securidaca tablet formulations completed the weight test because the percentage deviation in the... [more]

Research on cannabis oil has evolved to encompass the pharmaceutical industry for the therapeutic potential of the active compounds for pathologies such as Alzheimer, auto-immune disorders, and cancer. These debilitating diseases are best treated with cannabinoids such as tetrahydrocannabinol (∆9-THC), cannabigerol (CBG), and cannabinol (CBN), which relieve neuropathic pain and stimulate the immune system. We extracted cannabinoids from plants with supercritical CO2 and produced an extract with a total yield close to 26%. The three-level Box−Behnken experimental design considered four factors: Temperature, pressure, CO2 flow rate, and processing time, with predetermined parameters at low, medium, and high levels. The mathematical model was evaluated by regression analysis. The yield of ∆9-THC and CBG reached a maximum after 2 h and 15 g/min of CO2, 235 bar, 55 °C (64.3 g THC/100 g of raw material and 4.6 g CBG/100 g of raw material). After another 2 h of extraction time, the yield of C... [more]

Change regulation of the physical properties of fluid is key to accurately predicting multiphase fluid flow in the production wellbore of CO2 flooding reservoirs. Given the characteristics of significant changes in pressure, temperature, and CO2 content in the whole wellbore of production wells in CO2 flooding reservoirs, this paper systematically studied the change rules of volume factor, viscosity, density, and solubility of well fluid for pressure 5~30 MPa, temperature 20~120 °C, and CO2 content 10~90% through single degassing PVT experiments. According to the experimental results, the volume factor of crude oil increases first and then decreases with the pressure increase. At the bubble point pressure (20 MPa), the volume factor of crude oil can reach 1.89 at high temperatures. The volume factor can be increased from 1.28 to 1.44 at 8 MPa when the temperature increases from 20 °C to 120 °C. Under the bubble point pressure, the increase in pressure increases the solubility of CO2, a... [more]

Presently, the use of fossil fuels is not ecologically sustainable, which results in the need for new alternative energies such as biodiesel. This work presents a review of the classification of the lipidic feedstocks and the catalysts for biodiesel production. It also presents the pros and cons of the different processes and feedstocks through which biodiesel is obtained. In this context, cooking oil (WCO) has emerged as an alternative with a high potential for making the process sustainable. A detected limitation to achieving this is the high content of free fatty acids (FFA) and existing problems related to homogeneous and heterogeneous catalysts. To overcome this, the use of bifunctional catalysts is being evaluated by the scientific community. Thus, this work also explores the advances in the study of bifunctional catalysts, which are capable of simultaneously carrying out the esterification of free fatty acids (FFA) and the triglycerides present in the WCO. For the sake of an imp... [more]

Indirect fracturing from roof rock to coal using a horizontal well is a new and promising technology for coalbed methane surface exploitation in soft and low-permeability coal seams. In order to study the propagation law of hydraulic fractures across the coal−rock interface, a pore pressure cohesive element is used to establish a numerical model for indirect fracturing. Combined with practical engineering in a 3# coal seam in the Xinjing mine in China, the propagation behavior of hydraulic fractures across the coal−rock interface was researched, and the range of the horizontal well position for indirect fracturing was determined. The results show that: (1) the pore pressure cohesive element can be used to accurately simulate the interaction between hydraulic fractures and natural fractures, and the propagation of hydraulic fractures across the coal−rock interface. (2) As the vertical distance between the horizontal well and coal−rock interface decreases, the breakdown pressure of perfo... [more]