Search Results (11,638)

The heating energy consumption in public buildings in cold regions is notably significant, presenting substantial scope for energy savings and emission reductions. Flexible loads can actively participate in controlling the operation of the power grid, improving the energy utilization and the economy of the system. This study introduces flexible loads into the operation optimization of energy systems, establishing mathematical models for flexible thermal and electrical loads. A two-stage operation optimization method is proposed: the first stage simulates the starting and stopping control conditions of equipment at varying temperatures and times, selecting the optimal time period to regulate the thermal loads; the second stage employs a multi-objective particle swarm optimization algorithm to optimize the scheduling of the system’s electrical load. Finally, an empirical analysis is carried out in a public building in Shenyang City as an example, and the results indicate that optimal scheduling of flexible thermal and electrical loads reduces the daily operating cost of the energy supply system by RMB 124.12 and decreases carbon emissions by 22.7%. Full article

The China Seismo-Electromagnetic Satellite (CSES-01) is the first satellite of the space-based observational platform for the earthquake (EQ) monitoring system in China. It aims to monitor the ionospheric disturbances related to EQ activities by acquiring global electromagnetic fields, ionospheric plasma, energy particles, etc., opening a new path for innovative explorations of EQ prediction. This study analyzed 47 shallow strong EQ cases (Ms ≥ 7 and depth ≤ 100 km) recorded by CSES-01 from its launch in February 2018 to February 2023. The results show that: (1) For the majority (90%) of shallow strong EQs, at least one payload onboard CSES-01 recorded discernible abnormal signals before the mainshocks, and for over 65% of EQs, two or three payloads simultaneously recorded ionospheric disturbances; (2) the majority of anomalies recorded by different payloads onboard CSES-01 predominantly manifest within one week before or on the mainshock day, or occasionally about 11–15 days or 20–25 days before the mainshock; (3) typically, the abnormal signal detected by CSES-01 does not directly appear overhead the epicenter, but rather hundreds of kilometers away from the epicenter, and more preferably toward the equatorward direction; (4) the anomaly recognition rate of each payload differs, with the highest rate reaching more than 70% for the Electric Field Detector (EFD), Search-Coil Magnetometer (SCM), and Langmuir Probe (LAP); (5) for the different parameters analyzed in this study, the plasma density from LAP, and electromagnetic field in the ULF band recorded by EFD and SCM, and energetic electrons from the High-Energy Particle Package (HEPP) show a relatively high occurrence of abnormal phenomena during the EQ time. Although CSES-01 has recorded prominent ionospheric anomalies for a significant portion of EQ cases, it is still challenging to accurately extract and confirm the real seismic precursor signals by relying solely on a single satellite. The combination of seismology, electromagnetism, geodesy, geochemistry, and other multidisciplinary means is needed in the future’s exploration to get infinitely closer to addressing the global challenge of EQ prediction. Full article

The present work reports on the microencapsulation of Lacticaseibacillus rhamnosus GG (LGG) by the spray-drying process using a solution of starch, whey protein concentrate (WPC), soy lecithin and ascorbic acid as a carrier, with addition of different types of butters. The aim of this study was to examine the protective mechanism of six different butter samples on the viability rate of LGG bacteria directly after the spray-drying process and during storage for 4 weeks at 4 °C and 20 °C (±1 °C) based on hypothetical factors—the fatty acid’s chemical character and content, and its melting enthalpy. The viability of bacteria, moisture content, water activity, color properties, morphology, particle size of powder, melting enthalpy of butters and their fatty acids composition were evaluated. It is assumed that the highest viability may be indirectly influenced by the relationship between the highest content of proteins and sugars and the lowest content of fats and fatty acids, which is characteristic for butter with a reduced fat content. This butter contained also the least monounsaturated and polyunsaturated fatty acids. The highest number of viable LGG (for systems with reduced-fat butter, as well as salted and lactose-free butter) may be caused by (among other factors) by the lower content of palmitic acid (C16: 0). For these butters, it was also observed that cell viability increased with the increase in melting enthalpy. The results confirmed the protective role of selected butters, which indicates the possibility of using them in industrial processes to increase the durability of additives and products using probiotic powders obtained by spray-drying. Full article

A recent study reported the rapid growth of SiC single crystals of ~1.5 mm/h using high-purity SiC sources obtained by recycling CVD-SiC blocks used as materials in semiconductor processes. This method has gained attention as a way to improve the productivity of the physical vapor transport (PVT) method, widely used for manufacturing single crystal substrates for power semiconductors. When recycling CVD-SiC blocks by crushing them for use as sources for growing SiC single crystals, the properties and the particle size distribution of the material differ from those of conventional commercial SiC powders, making it necessary to study their effects. Therefore, in this study, SiC single crystals were grown using the PVT method with crushed CVD-SiC blocks of various sizes as the source material, and the growth behavior was analyzed. Simulation results of the temperature distribution in the PVT system confirmed that using large, crushed blocks as the SiC source material generates a greater temperature gradient within the source compared to conventional commercial SiC powder, making it advantageous for rapid growth processes. Additionally, when the large, crushed blocks were vertically aligned, good crystal quality was experimentally achieved at high growth rates, even under non-optimized growth conditions. Full article

In recent years, the fast growth of computational power has allowed the application of computational fluid dynamics (CFD) in a wide range of areas of interest, such as gas–solid unit operations. In this context, the multiphase particle-in-cell (MP-PIC) method appears as an option to represent fluid–particle and particle–particle interactions, avoiding the complexity of tracking each particle and the high computational cost derived from this. The MP-PIC method can represent the particles as a group with the same characteristics, allowing the simulation of gas–solid systems at different scales. To achieve this, the particle–particle interactions are simplified using the solid stress tensor to represent them; this does not require explicit expressions. This approach has a low computational cost, allowing the simulation of industrial cases using just workstations. This paper provides a review of the literature on the solid stress tensor and its commercial and non-commercial applications, including its historical and mathematical development in the description of particle–particle interactions. In addition, to consolidate the knowledge and advancing understanding in this crucial aspect of multiphase flow simulations, this review identifies the current challenges and opportunities for future research in multiphase systems based on the solid stress tensor. In addition, this review identifies the current challenges and opportunities for future research in multiphase systems based on the solid stress tensor. Full article

The spread of airborne diseases such as COVID-19 underscores the need for effective indoor air quality control. This review focuses on ventilation strategies and portable air purifiers as key mitigation solutions. Ventilation systems, including natural and mechanical approaches, can reduce pathogen concentrations by improving airflow. However, combining ventilation with portable air purifiers, particularly those using HEPA filters, ESP filters, and UV-C radiation, can enhance Indoor air quality. While HEPA and ESP filters focus on trapping airborne particles, UV-C radiation can inactivate pathogens by disrupting their RNA. A review of UV air purifiers reveals a lack of studies on their efficacy and effectiveness in real-world settings. A thorough investigation into the performance of this mitigation solution is necessary, focusing on varying key factors, such as purifier placement, airflow dynamics, and UV dosage, to ensure optimal effectiveness. High-fidelity computational methods are essential in accurately assessing these factors, as informed by the physics of airborne transmission. Such advanced computations are necessary to determine the viability of portable UV air purifiers in mitigating airborne transmission in enclosed environments such as hospitals and public spaces. Integrating advanced air purification technologies with proper ventilation can improve safety in indoor environments and prevent future disease-related outbreaks. Full article

Optimizing control rate parameters is one of the key technologies in motor control systems. To address the issues of weak robustness and slow response speed in traditional adaptive control strategies, an adaptive control system based on sliding mode control is proposed to enhance the overall performance of permanent magnet synchronous motors. The Non-dominated Sorting Genetic Algorithm II and Multi-objective Particle Swarm Optimization are employed to effectively optimize control parameters, thereby mitigating motor torque and speed overshoot. A Partial Sample Shannon Entropy Evaluation method, leveraging entropy theory in conjunction with the Z-score method, is introduced to facilitate the feedback regulation of the optimization process by assessing motor output torque. Simulation results confirm that the proposed control strategy, in combination with the optimized control rate parameters, leads to substantial improvements in motor performance. Compared to traditional adaptive control strategies, the proposed approach improves the motor’s steady-state response speed by 42% and reduces rotor error during system fluctuations by 23%, significantly enhancing the motor’s response speed and robustness. Following parameter optimization, speed and torque overshoot are reduced by 38% and 10%, respectively, resulting in a significant improvement in the stability and precision of the motor control system. Full article

In space environments, radiation particles affect the stored values of SRAM cells, and these effects, such as single-event upsets (SEUs) and single-event multiple-node upsets (SEMNUs), pose a threat to the reliability of systems used in the space industry. To mitigate the impacts of SEUs and SEMNUs, this paper proposes the Read Stability Improved and Low Power (RSLP16T) SRAM cell. It was confirmed that in SEU-induced simulations, all nodes of the RSLP16T could be restored with a charge amount of less than 100 fC. Additionally, it was verified that a similar level of restoration was possible for SEMNUs occurring in pair of storage nodes. The proposed cell achieves a high level of read stability due to a high pull-down cell ratio (current ratio, CR) at the storage nodes and the fact that only a pair of nodes is in contact with the bit lines during read operations. Because all node paths use a stacking structure for internal transistor configuration and a relatively higher number of cells are composed of PMOS, it consumes the least hold power. While these improvements come at the cost of slightly increased delay time and area, performance evaluation revealed that the equivalent quality metric (EQM) was the highest, indicating that the benefits outweigh the drawbacks. The proposed integrated circuit is implemented in the 90 nm CMOS process and operated on 1 V supply voltage. Full article

Nano-silica (NS) is an ideal modifier for mortar materials, and exploring the evolution of the fractal dimension of the pore structure in NS-modified mortar is crucial for elucidating the mechanism by which NS enhances mortar strength. In this study, NS reinforced mortar was prepared using an NS sol solution, which inhibited the aggregation of NS particles. The relationship between the strength and pore structure of NS-modified mortar was quantitatively analyzed based on fractal dimension theory and gray correlation degree. The experimental system evaluated the mortar strength, pore structure distribution, and micro-morphology. Based on this evaluation, the fractal dimension of the mortar pore volume was calculated in detail. Subsequently, models for mortar strength and NS content were further established using grey analysis. The results indicate that NS significantly enhances the strength of mortar while also increasing its porosity due to reduced fluidity. NS can improve the compressive strength of mortar by up to 35%. The curve fitting of volume fractal dimension and box dimension is effective and can accurately reflect the complexity of the pore structure. The calculation of the grey correlation analysis model shows that the impact of varying silica content on the mechanical properties of mortar specimens is not linear; the distribution and quantity of bubbles are the main factors affecting the strength of the specimen. Full article

As the proportion of new energy access increases year by year, the resulting energy imbalance and voltage/trend distribution complexity of the distribution network system in the spatio-temporal dimension become more and more prominent. The joint introduction of electromagnetic rotary power flow controller (RPFC) and energy router (ER) can improve the high proportion of new active distribution network (ADN) consumption and power supply reliability from both spatial and temporal dimensions. To this end, the paper proposes an ADN expansion planning method considering RPFC and ER access. A two-layer planning model for RPFC and ER based on spatio-temporal characteristics is established, with the upper model being the siting and capacity-setting layer, which takes the investment and construction cost of RPFC and ER as the optimization objective, and the lower model being the optimal operation layer, which takes the lowest operating cost of the distribution network as the objective. The planning model is solved by a hybrid optimization algorithm with improved particle swarm and second-order cone planning. The proposed planning model and solving algorithm are validated with the IEEE33 node example, and the results show that the joint access of RPFC and ER can effectively improve the spatial-temporal distribution of voltage in the distribution network and has the lowest equivalent annual value investment and operation cost. Full article

This article reports on field tests devoted to the emissions of particles from gas turbines (GT) and more particularly to the formation of soot and its suppression by fuel additives. These field tests involved four heavy-duty gas turbines used as power generators and equipped with air atomization systems. These machines were running on natural gas, No. 2 distillate oil, heavy crude oil and heavy fuel oil, respectively. The GT running on natural gas produced no soot or ash and its upstream air filtration system in fact allowed lower concentrations of exhaust particles than those found in ambient air. Soot emitted when burning the three liquid fuels (No. 2 distillate; heavy crude oil; and heavy oil) was effectively reduced using fuel additives based on iron(III), cerium(III) and cerium(IV). Cerium was found to be very effective as a soot suppressant and gave rise to two surprising effects: cerium(III) performed better than cerium(IV) and a “memory effect” was observed in the presence of heat recovery boilers due to the deposition of active cerium species. All of the reported results, both regarding natural gas emissions and soot reduction, are original. A review of the soot formation mechanisms and a detailed interpretation of the test results are provided. Full article

The oral bioavailability of curcumin is inherently low, which significantly limits its application in food systems. The objective of this study was to evaluate the impact of high-pressure processing on the stability and bioaccessibility of curcumin within an emulsion gel during simulated gastrointestinal transit and to assess its cellular uptake. Our findings suggest that increasing pressure levels and high κ-carrageenan concentrations can enhance the stability of the curcumin delivery system. Elevated κ-CG concentrations were found to retard the action of proteases on dissociating protein molecules from the gel network. The emulsion gel effectively slowed the release of free fatty acids and reduced the curcumin release rate during the gastric phase. Scanning electron microscopy images revealed that higher pressures induced the formation of a more uniform and dense network structure in the gel. While the gel network structures were well-preserved after gastric digestion, they were disrupted into smaller particles following intestinal digestion, with particle size increasing with higher applied pressures. Cytotoxicity assays indicated that the digesta from the intestinal phase was highly toxic to Caco-2 cells. Among the tested samples, the emulsion gel prepared with 1.0% κ-CG at 600 MPa demonstrated the highest curcumin bioavailability, reaching 63.82 ± 7.10%. These findings underscore the potential of HPP-induced emulsion gels as a viable delivery system for enhancing curcumin bioaccessibility and cellular uptake. Full article

Scanning micromirrors represent a crucial component in micro-opto-electro-mechanical systems (MOEMS), with a broad range of applications across diverse fields. However, in practical applications, several factors inherent to the fabrication process and the surrounding usage environment exert a considerable influence on the accuracy of measurements obtained with the micromirror. Therefore, it is essential to calibrate the scanning micromirror and its measurement system. This paper presents a novel scanning micromirror calibration method based on the prediction of a particle swarm optimization-least squares support vector machine (PSO-LSSVM). The objective is to establish a correspondence between the actual deflection angle of the micromirror and the output of the measurement system employing a regression algorithm, thereby enabling the prediction of the tilt angle of the micromirror. The decision factor ($R^2$) for this model at the x-axis reaches a value of 0.9947. Full article

The application of coal technologies for energy generation leads to high pollutant emissions. Thus, governmental and international organizations have created new programs and laws for monitoring emissions. Recently, the government of Kazakhstan has introduced regulations for the measurement of emissions produced by factories and power plants. However, the requirements and Corecommendations for the monitoring methods have not been defined. Therefore, this article addresses the problem and focuses on determining the measurement errors made by optical SGK510 and electrochemical POLAR devices used for coal power plants. The hypothesis is based on the fact that there are currently no systems for monitoring probe drying, and its implementation is expensive. The main methods are analyzed, namely their operation, taking into account the presence of water particles in samples, and the possibility of using adjustment coefficients is considered. The main pollutants chosen for analysis are CO, NO, NO₂, NO_x, SO₂, and O₂. Using the Broich–Pagan test, homoscedasticity was determined, and the Fisher test showed the possibility of using tuning coefficients. The data for the optical method were compared to measurements taken using Inspector 500. The error for SO₂ determination was 7.19% for NO, 44.0985% for NO₂, 733.26% for NO_x, 7.39% for O₂, 2.75% for CO, 60.81%. The comparison between SGK510 and POLAR demonstrated the following errors: for CO—1.5%, for NO_x—82.4405%, for SO₂—41.17%, for O₂—11.61%. According to the Fisher criteria analysis of the optical method, only SO₂ and CO values measured by SGK510 in comparison to Inspector 500 had close similarity, while others demonstrated high deviations. The significance tests were carried out by Fisher’s, t-test, and ANOVA methods. For the electrochemical measurement, only CO values had close similarity. In the future, methods will be proposed to improve the accuracy of the system while reducing maintenance costs, as well as cleaning sampling systems. The multicomponent analysis application for accuracy improvement with the exhaust gas humidity, temperature, and flow consideration was recommended as a possible solution. Full article

This paper proposes a two-stage, three-layer stochastic robust model and its solution method for a multi-energy access system (MEAS) considering different weather scenarios which are described through scenario probabilities and output uncertainties. In the first stage, based on the principle of the master–slave game, the master–slave relationship between the grid dispatch department (GDD) and the MEAS is constructed and the master–slave game transaction mechanism is analyzed. The GDD establishes a stochastic pricing model that takes into account the uncertainty of wind power scenario probabilities. In the second stage, considering the impacts of wind power and photovoltaic scenario probability uncertainties and output uncertainties, a max–max–min three-layer structured stochastic robust model for the MEAS is established and its cooperation model is constructed based on the Nash bargaining principle. A variable alternating iteration algorithm combining Karush–Kuhn–Tucker conditions (KKT) is proposed to solve the stochastic robust model of the MEAS. The alternating direction method of multipliers (ADMM) is used to solve the cooperation model of the MEAS and a particle swarm algorithm (PSO) is employed to solve the non-convex two-stage model. Finally, the effectiveness of the proposed model and method is verified through case studies. Full article