A low-temperature aerosol cooling and lubrication grinding test bench was built to evaluate the cooling and lubrication performance of the low-temperature aerosol. The mechanism of grinding residual stresses in the inner ring raceway under the coupling effect of grinding force and grinding heat was studied, and the effects of the grinding process parameters and cooling and lubrication conditions on the distribution state of the grinding residual stresses in the surface layer of the inner ring raceway were revealed. The results showed that reducing the initial temperature of the grinding fluid could reduce the residual tensile stresses on the raceway surface. The results also showed that the low-temperature aerosol cooling lubrication method is conducive to the generation of the axial residual compressive stress of −500 MPa and tangential residual compressive stress of −300 MPa in the inner ring raceway surface layer of the bearing. Compared with the convective heat transfer coefficient... [more]

Up to 80% of hydrogen production is currently carried out through CO2 emission-intensive natural gas reforming and coal gasification. Water-splitting electrolysis using renewable energy (green H2) is the only process that does not emit greenhouses gases, but it is a quite energy-demanding process. To significantly contribute to the clean energy transition, it is critical that low-carbon hydrogen production routes that can replace current production methods and can expand production capacity to meet new demands are developed. A new path, alternative to steam reforming coupled with CCS (blue H2) that is based on methane cracking, in which H2 production is associated with solid carbon instead of CO2 (turquoise H2), has received increasing attention recent years. The reaction takes place inside the liquid bath, a molten metal reactor. The aim of this article is to model the main kinetic mechanisms involved in the methane cracking reaction with molten metals. The model developed was validat... [more]

Aiming at the synergy between a system’s carbon emission reduction demand and the economy of peak shaving operation in the process of optimizing the flexible resource peaking unit portfolio of a multi-energy power system containing large-scale electric vehicles, this paper proposes a low-carbon optimal scheduling model for peak shaving resources in multi-energy power systems considering large-scale access for electric vehicles. Firstly, the charging and discharging characteristics of electric vehicles were studied, and a comprehensive cost model for electric vehicles, heat storage, and hydrogen storage was established. At the same time, the carbon emission characteristics of multi-energy power systems and their emission cost models under specific carbon trading mechanisms were established. Secondly, the change characteristics of the system’s carbon emissions were studied, and a carbon emission cost model of multi-energy power was established considering the carbon emission reduction de... [more]

Interval forecasting has become a research hotspot in recent years because it provides richer uncertainty information on wind power output than spot forecasting. However, compared with studies on single wind farms, fewer studies exist for multiple wind farms. To determine the aggregate output of multiple wind farms, this paper proposes an interval forecasting method based on long short-term memory (LSTM) networks and copula theory. The method uses LSTM networks for spot forecasting firstly and then uses the forecasting error data generated by LSTM networks to model the conditional joint probability distribution of the forecasting errors for multiple wind farms through the time-varying regular vine copula (TVRVC) model, so as to obtain the probability interval of aggregate output for multiple wind farms under different confidence levels. The proposed method is applied to three adjacent wind farms in Northwest China and the results show that the forecasting intervals generated by the pro... [more]

To boost the operational performance of a non-aqueous DES electrolyte-based vanadium-iron redox flow battery (RFB), our previous work proposed a double-layer porous electrode spliced by carbon paper and graphite felt. However, this electrode’s architecture still needs to be further optimized under different operational conditions. Hence, this paper proposes a multi-layer artificial neural network (ANN) model to predict the relationship between vanadium-iron RFB’s performance and double-layer electrode structural characteristics. A training dataset of ANN is generated by three-dimensional finite-element numerical simulations of the galvanostatic discharging process. In addition, a genetic algorithm (GA) is coupled to an ANN regression training process for optimizing the model parameters to elevate the accuracy of ANN prediction. The novelty of this work lies in this modified optimal method of a double-layer electrode for non-aqueous RFB driven by a machine learning (ML) model coupled wi... [more]

Fig fruits have recently received more attention by consumers for their quality as either fresh or dried fruits and, consequently, growers are becoming more interested in the cultivation of this species. Figs are mainly consumed as processed fruits (dried, marmalade, jam, etc.), but limited attention has been paid to new possible processing applications of several local cultivars grown in Mediterranean countries. This study aimed to investigate both the morpho-pomological characteristics and consumer sensory ratings (two groups: students and technicians) for four fig cultivars processed as a new type of product, ‘dried fig disks’. The results showed that three out of the four cultivars (Processotto Nero, Natalese Nera, and Verde di Natale) had good pomological characteristics such as fruit weight and skin color, as well as easy peeling, yield, ripening time, and TSS. The same cultivars received positive hedonic scores for appearance (>5 on a 10-point hedonic scale), flavor (4−6 on a 10... [more]

Fabrication of self-reinforced polyethylene terephthalate (PET) has been achieved through the in situ generation of PET fibrils via a spun bond process. The reinforcement fibrils created from the PET with higher Tm are made from a unique in situ processing method. As a result, the fibrils are well dispersed and distributed in the lower Tm PET matrix. The high degree of molecular similarity affords perfect interfaces between the matrix and dispersed phase, leading to excellent stress transfer from the matrix to the dispersed fibrils. While the extremely large interfaces from the nanofibrillation process can maximize the advantage of the excellent molecular similarity of the self-reinforced polymeric composites, few studies have been conducted to research nanofibrillar self-reinforced polymeric composite systems. Hence, as a proof of concept, this work provides new insight into an approach for developing a self-reinforced polymeric system with a nanofibrillation process. This process inc... [more]

The rock coring of the reservoir in the Bohai A field is difficult. The cores of the target section in the study area are loose, making it difficult to accurately measure the core-bound water saturation. The purpose of this research was to develop and validate a method for calculating a reservoir core-bound water saturation ratio using the cast thin section. First, pepper noise denoising and image enhancement were performed on the thin section by median filtering and gamma variation. Based on this, the enhanced sheet images were thresholded for segmentation by the two-dimensional OTSU algorithm, which automatically picked up the thin section pore-specific parameters. Then, the thin section image was equivalent to a capillary cross-section, while the thin film water fused to the pore surface was observed as bound water. For hydrophilic rocks with a strong homogeneity, the area of thin film water in the pore space of the sheet was divided by the total area of the pore space, which produc... [more]

The use of carbide catalysts in Fischer−Tropsch synthesis (FTS) is an active area of research, as carbide phases have been shown to improve the stability and performance of catalysts in this reaction. This study compared the catalytic activity and product selectivity of cobalt and iron catalysts supported on SBA-15, with and without a carbide phase and reduction treatment before the reaction. Results showed that the presence of the carbide phase had a noticeable influence on the catalytic behavior of the catalysts, and the reduction of the catalyst with hydrogen also affected the product selectivity. The presence of the carbide phase in non-reduced cobalt catalysts resulted in increased selectivity to liquid phase products, as evidenced by a CO conversion of 37% with 68% selectivity to the products in the liquid phase. The catalytic activity of the iron carbide catalyst for CO dissociation was found to be 38% after reducing the catalyst with hydrogen, leading to the formation of more a... [more]

In this study, conditions were determined to obtain a solid wax with a waxy ester content of more than 25% from the hydrotreating of palm oil. The experiments were conducted in a pilot-scale fixed-bed reactor. The influence of temperature, liquid hourly space velocity (LHSV), and pressure on the conversion of triglycerides were evaluated using a nickel molybdenum catalyst (NiMo/Al2O3). The variables were evaluated between 240 and 260 °C, 1 and 2 h−1 and 41 and 55 bar, respectively. Based on these results, the best conditions were T:240−260 °C; P: 90 bar; LHSV: 1.5 h−1; hydrogen/oil ratio 472 LN/L with a conversion around 60 wt%; and a selectivity towards waxy esters of 40 wt%. These conditions were then validated with a second catalyst (NiMoB/Al2O3), yielding a triglyceride conversion of about 60 wt% and a waxy ester concentration of around 30 wt%.

The transportation sector is facing a profound challenge to utilize a greater proportion of sustainable substitutes in relation to oil-derived products [...]

“Seong-Yeun Yoo, In-Kook Kang, Namhyun Kim, Sanggyu Kim, Kangil Choe” were not included as authors in the original publication [...]

Rolling element bearings (REBs) are the most frequent cause of machine breakdowns. Traditional methods for fault diagnosis in rolling bearings rely on feature extraction and signal processing techniques. However, these methods can be affected by the complexity of the underlying patterns and the need for expert knowledge during signal analysis. This paper proposes a novel signal-to-image method in which the raw signal data are transformed into 2D images using continuous wavelet transform (CWT). This transformation enhances the features extracted from the raw data, allowing for further analysis and interpretation. Transformed images of both normal and faulty rolling bearings from the Case Western Reserve University (CWRU) dataset were used with deep-learning models from the ResNet family. They can automatically learn and identify patterns in raw vibration signals after continuous wavelet transform is used, eliminating the need for manual feature extraction. To further improve the trainin... [more]

Aiming at the common problems of the high working resistance, low soil disturbance, and high rates of missed extraction in the operation of carrot combine harvesters, a high-efficiency drag-reducing bionic soil-loosening shovel was designed in this study. The physical parameters of the soil and carrots were measured, and the bionic drag-reducing shovel was designed using the badger claw toe as a bionic prototype. The shovel wing structures were designed. Based on the EDEM discrete element simulation technology, a multi-element simulation model of the shovel−soil−carrot contact was established to determine the effects of the operating speed and sliding angle of the shovel handle on the resistance. The effects of the blade inclination angle and blade opening angle on the resistance, carrot extraction force, and soil disturbance rate were also studied. The results show that the resistance increases with an increase in operating speed. With a blade angle (α) and blade inclination angle (β)... [more]

Amine solvent has attracted much attention due to its high CO2 capture level and wide application range, but its high energy consumption for recycling restricts its large-scale commercialization. In this work, a multi-objective optimization technology based on the group contribution method was used to select potential amine solvents for CO2 capture. This computer-aided molecular design method considers the thermodynamic and kinetic properties of the candidate solvent and evaluates the influence of relevant parameters on solvent performance. Compared with previous experimental methods used to optimize solvent, this method selects potential solvents from a large number of solvent databases based on group contribution. Firstly, a corresponding classification database was established for various kinds of amine solvents. Then, the traditional experiments were used to verify and screen solvents. At the same time, the method was applied to 31 amine absorbents concerning solubility, molar volu... [more]

The increasing cadmium (Cd) levels in agricultural soils have become a worldwide concern for food crop security. Cd accumulation in the soil-plant system is closely related to other coexisting factors. In this study, the effects of different levels of Zn or Ni on Cd accumulation in tomato plants and on the rhizosphere soil bacterial community structure were analyzed by coupling pot experiments with high-throughput sequencing. The results demonstrated that tomato plants (Lycopersicon esculentum) in Zn-Cd and Ni-Cd co-contaminated soils exhibited lower relative growth rates. Co-contamination at low levels tended to reduce the bioaccumulation of heavy metals in the roots of plants, whereas increased contaminant concentrations produced the opposite effect. In the presence of 200 mg/kg Zn or 20 mg/kg Ni, the biomass of plant roots increased by 4.95−23.16% and the Cd content of the plant roots decreased by 17.36−68.93% due to the antagonistic effects between Cd and Zn/Ni. In addition, the ri... [more]

Undesired solid precipitation in coal slag at high temperatures can cause serious blockages, or even the shutdown of coal gasifiers, due to a rapid increase in slag viscosity. In this study, the solid precipitation behaviors of coal slag from different primary phases and under different atmospheres were both experimentally and theoretically investigated. Our results demonstrated that the viscosity of the coal slag in the primary phase of mullite was strongly influenced by the atmosphere at a typical tapping temperature of 1300 °C because of the high content of network formers. The viscosity of the partially crystallized slag was significantly affected by solid precipitation behavior. Iron was converted to magnetite and hematite in air and was reduced to metallic iron under a reducing atmosphere. Increasing CaO content improved both the iron reduction reaction and the slag crystallization behavior. Anorthite precipitation was largely inhibited under a mild reducing atmosphere, leading t... [more]

The graphene oxide (GO) membrane holds great promise in desalination and green energy fields due to its naturally occurring nanochannels, which provide significant advantages in gas and ion filtration. In this study, the sizes and distributions of nanopore/channels in GO membranes and the relationship of GO flakes size and membrane thickness are explored by molecular dynamics simulations. Our results demonstrate that the size of GO flakes influences the distribution of nanopore sizes in GO membranes, while it almost has no influence on the total nanopore area in membranes with the same thickness. Additionally, our findings confirm that the total nanopore area of the GO membranes decreases exponentially as the membrane thickness increases, which is consistent with experimental observations. To expand the range of nanopore size regulation, we developed a columnar-array substrate model to create GO membranes customized for specific filtration functions, such as virus filtration. Our findi... [more]

The rise of artificial intelligence (AI)-based image analysis has led to novel application possibilities in the field of solvent analytics. Using convolutional neural networks (CNNs), better and more automated analysis of optically visible phenomena becomes feasible, broadening the spectrum of non-invasive measurements. These so-called smart sensors have attracted increasing attention in pharmaceutical and chemical process engineering; their additional sensor data enables more precise process control as additional process parameters can be monitored. This contribution presents an approach to analyzing single rising droplets to determine their physical properties; for example, geometrical parameters such as diameter, projection area and volume. Additionally, the rising velocity is determined, as well as the density and interfacial tension of the rising liquid droplet, determined from the force balance. Thus, a method was developed for analyzing liquid−liquid properties suitable for real... [more]

Ensuring the accuracy of flow measurement is crucial to promoting high-quality cigarette production. In order to monitor the working status of flowmeters, this paper proposes an anomaly detection method based on the sliding-window recursive Lasso (Least absolute shrinkage and selection operator), which is able to track the changes in flowmeter operating conditions by self-adapting model parameters based on observed measurements. Due to the frequent mode switch and high sampling frequency of flow data, this paper introduces the sliding-window strategy to remove the effect of outdated data and accelerate the optimization. The tracking errors are used as a measure of anomaly and different thresholds are introduced based on the operating manual of cigarette production, which are used to distinguish between mode switch and flowmeter anomalies. The method’s effectiveness is verified by detecting flowmeter anomalies in a real cigarette production line. The mean absolute error (MAE) is 8.1479... [more]

The exploration of natural substrates for microbial conversion to synthesize industrial platform and fuel chemicals seems to be inevitable within a circular bioeconomy context. Hemicellulose is a natural carbohydrate polymer consisting of a variety of pentose (C5) sugar monomers such as arabinose, mannose, erythrose, and xylose. Among the C5 sugars, L-arabinose (L-Ara) is the second-most-abundant pentose sugar in the lignocellulosic biomass after xylose. L-Ara has been used as an industrial carbon source to produce several value-added chemicals such as putrescine, which is used to synthesize polymers in the textile industry; sugar alcohols that are used as sweeteners in diet foods; and amino acids such as L-lysine, L-glutamate, L-arginine, and L-ornithine, which are used in nutritional supplements, fertilizers, and other products in the food and beverage industries. L-Ara, a natural non-caloric sweetener, is used as a substitute in the food and beverage industry, when the risk of blood... [more]

The efficient use of coal resources and the safe operation of coal-fired boilers are hindered by high-temperature corrosion caused by corrosive sulphur components. To predict the impact of sulphur−nitrogen interactions on sulphur’s evolution and its mechanism of action, a conventional sulphur component evolution model (uS−N) and an improved sulphur component evolution model (S−N) that considers sulphur−nitrogen interactions were proposed in the present study. The models were built using OpenFOAM−v8 software for the coal combustion process, and the generation of SO2, H2S, COS, and CS2 was simulated and analysed under different air excess coefficients. The simulations were conducted to analyse the patterns of SO2, H2S, COS, and CS2 generation at different air excess factors. The results show that, compared with the uS−N condition, the simulated values of coal combustion products (SO2, H2S, COS, and CS2) under the S−N condition were closer to the experimental values, and the errors of dif... [more]

Alternative sour2ces of energy are on the rise primarily because of environmental concerns, in addition to the depletion of fossil fuel reserves. Currently, there are many alternatives, approaches, and attempts to introduce alternative energy sources in the field of transport. This article centers around the need to explore additional energy sources beyond the current ones in use. It delves into individual energy sources that can be utilized for transportation, including their properties, production methods, and the advantages and disadvantages associated with their use across different types of drives. The article not only examines the situation in the Czech Republic but also in other nations. In addition to addressing future mobility, the thesis also considers how the utilization of new energy sources may impact the environment.

The multi-objective optimization of methanol distillation is a critical and complex issue in the methanol industry. The three-column methanol distillation scheme is first simulated with Aspen Plus to provide the initial value of the NSGA-III algorithm. The operating parameters are optimized through the Python-Aspen platform. The total annual cost and CO2 emissions are considered the objective function. A small value of indicator generational distance can be achieved by increasing the number of generations, which is helpful in improving algorithm convergence. The NSGA-III algorithm has good convergence and distribution performance. By comparing the optimized results with the original ones, the total annual cost and CO2 emissions are, respectively, reduced by 5.35% and 12.80% when the operating parameters of the methanol distillation sequence are optimized through NSGA-III. As a result, substantial economic and energy savings can be made, offering great potential to improve the performan... [more]

The involvement of liquefied petroleum gas (LPG), which is highly combustible and explosive, greatly increases risk in road transport. A 3D numerical model was conducted in FLACS, which depicts the dynamic process and variation of combined effects along the multi-directions of LPG explosion under an actual case. With the simulation of scenarios, power-law explosion and fireball models were used to reproduce the results, and the dynamic evolution of specific parameters during the LPG explosion process was analyzed. The results reveal that the LPG explosion’s expansion around the expressway moved along the spaces between obstacles, while conditions at the site of the accident had an enhancement effect on LPG/air mixture accumulation. The propagation trajectory of the shock wave in the horizontal direction presented a regular circle within 623.73 ms, and the overpressure was enough to lead to extensive damage to surrounding structures. Further, shock wave-driven overpressure brought hazar... [more]