The wettability of coal is an important factor influencing hydraulic stimulation. Field-trial data has proven that high-pressure N2 injection plays a positive role in increasing the coalbed methane (CBM) production rate. For the purpose of investigating the mechanism by which N2 promotes the gas rate, multiple experiments were conducted sequentially on the wettability of anthracite under different N2 pressures. Testing of the coal surface contact angle was conducted under 0.1−8 MPa nitrogen pressure using a newly built contact angle measuring device. The coal samples were collected from the Xinjing Coal Mine in the Qinshui Basin, China. The test results revealed that the contact angle increased with increasing N2 pressure. That is, the contact angle was 77.9° at an N2 pressure of 0.1 MPa and gradually increased to 101.4° at an infinite N2 pressure. In contrast, the capillary pressure decreased with an increasing N2 pressure, from 0.298 MPa to −0.281 MPa. The relationship between contac... [more]

In order to develop a highly efficient and stable high-temperature heat pump to realize high-efficient electrification in the industrial sector, performance of high-temperature heat pumps with a flash tank vapor injection and sub-cooler vapor injection are compared under different evaporation temperatures, condensation temperatures, compressor suction superheat degrees, subcooling degrees and compressor isentropic efficiencies. The results show that the COP, injection mass flow ratio and VHC of the FTVC are higher than those of the SVIC-0, SVIC-5, SVIC-10 and SVIC-20 under the same working conditions, while the discharge temperature of the FTVC is approximately equal to that of the SVIC-0 and lower than those of the SVIC-5, SVIC-10 and SVIC-20. When the evaporation temperature, the condensation temperature and injection pressure are 55 °C, 125 °C and 921.4 kPa, respectively, the system COP of the FTVC is 4.49, which is approximately 6.7%, 7.3%, 7.8% and 8.9% higher than those of the SV... [more]

The use of integrated plasma-activated water (PAW) with micro/nanobubbles (MNBs), ultraviolet (UV) photolysis, and ultrasonication (US) for the synergistic efficiency of Escherichia coli inactivation in chicken meat was investigated. A 2k factorial design was employed to optimize the combined treatment parameters for pathogen disinfection in Design of Experiments (DOE) techniques. Its effectiveness was evaluated based on electrical conductivity (EC), oxidation−reduction potential (ORP), hydrogen peroxide (H2O2) concentration, and E. coli inactivation. The most significant impact on E. coli reduction was observed for MNBs, UV treatment time, and their interaction (MNBs and UV). Optimal E. coli inactivation (6 log10 CFU/mL reduction) was achieved by combining PAW with MNB and UV for 10 and 20 min, respectively. Integrating PAW with appropriate supplementary technologies enhanced E. coli inactivation by 97% compared to PAW alone. This novel approach provides a promising alternative for pa... [more]

To achieve effective and accurate segmentation of photovoltaic panels in various working contexts, this paper proposes a comprehensive image segmentation strategy that integrates an improved Meanshift algorithm and an adaptive Shi-Tomasi algorithm. This approach effectively addresses the challenge of low precision in segmenting target regions and boundary contours in routine photovoltaic panel inspection. Firstly, based on the image information of photovoltaic panels collected under different environments by cameras, an improved Meanshift algorithm based on platform histogram optimization is used for preliminary processing, and images containing target information are cut out; then, the adaptive Shi-Tomasi algorithm is used to extract and screen feature points from the target area; finally, the extracted feature points generate the segmentation contour of the target photovoltaic panel, achieving accurate segmentation of the target area and boundary contour of the photovoltaic panel. Ex... [more]

This study shows the experimental data obtained by Raman spectroscopy to evaluate the structural changes of vegetable lubricants modified with montmorillonite after tribological tests. The analysis of the friction factor and limiting load of wear in the test for the examined grease compound shows a substantial effect on this parameter for grease. A change in the evaluated tribo-parameter results in a modification of the structure of the tested lubricant and changes in the protection efficiency of the tribological system. The amount of thickener, oil base and additive in the grease structure has an influence on the value of anti-wear properties, as shown by the data obtained in the tribological test described in this paper. The Raman spectroscopy tests showed that, in the tribological processes, some of the ingredients undergo an oxidative reaction, which leads to the formation of oxygenated organic substances that form an organic layer on the metal surface and counteract the wear of th... [more]

Polymerization products are indispensable for our daily life, and the relevant modeling process plays a vital role in improving product quality. However, the model identification of the related process is a difficult point in industry due multivariate, nonlinear and time-varying characteristics. As for the conventional offline subspace identification methods, the identification accuracy may be not satisfying. To handle such a problem, an enhanced on-line recursive subspace identification method is presented on the basis of principal component analysis and sliding window (RSIMPCA-SW) in this paper to obtain the state space model for polymerization. In the proposed on-line subspace identification approach, the initial L-factor is acquired by the LQ decomposition of the sampled historical data, firstly, and then it is updated recursively through the bona fide method after the new data have been handled by the sliding window rule. Subsequently, principal component analysis (PCA) is introdu... [more]

Hollow fiber (HF) organic solvent nanofiltration (OSN) membranes have recently attracted significant interest in the field of membrane technology. Their popularity stems from comparative advantages, such as high packing density, fouling resistance, and easier scalability for larger applications, unlike flat-sheet/spiral-wound OSN membranes, which may present challenges in these aspects. The combination of interfacial polymerization (IP) and HF configuration has opened up new opportunities for developing advanced membranes with enhanced separation performance that can be tailored for various OSN applications. The objective of this review is to discuss the latest advancements in developing thin film composite (TFC) HF membranes, with a focus on the IP method. Novel materials and processes are discussed in detail, emphasizing the fabrication of greener, interfacially polymerized HF OSN membranes. In addition, the commercial viability and limitations of TFC HF membranes are highlighted, pr... [more]

seeds, in particular, have been used for water and wastewater treatment due to their ability to remove many pollutants. Therefore, the present work aims to produce bioadsorbent materials by pyrolysis using biomass from the seed shell of Moringa oleifera to remove the drug Metronidazole present in an aqueous medium. The biochars produced were activated with phosphoric acid (H3PO4) and potassium hydroxide (KOH) to compare the material’s modifications and adsorption mechanisms with the biochar in nature (BCM). The biochars were characterized by Point-of-zero charges (pHpzc), Scanning Electron Microscopy (SEM), X-ray Diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. The studies showed that the adsorption behavior varied with the pH of the solution. The adsorption study verified that the activated biochars presented better results, so in the kinetic study, the adsorption behavior occurred rapidly in the initial minutes until stabilizing within 3−4... [more]

A major operation in petroleum refinery plants, blend scheduling management of stocks and their mixtures, known as blend-shops, is aimed at feeding process units (such as distillation columns and catalytic cracking reactors) and production of finished fuels (such as gasoline and diesel). Crude-oil, atmospheric residuum, gasoline, diesel, or any other stream blending and scheduling (or blend scheduling) optimization yields a non-convex mixed-integer nonlinear programming (MINLP) problem to be solved in ad hoc propositions based on decomposition strategies. Alternatively, to avoid such a complex solution, trial-and-error procedures in simulation-based approaches are commonplace. This article discusses solutions for blend scheduling (BS) in petroleum refineries, highlighting optimization against simulation, continuous (simultaneous) and batch (sequential) mixtures, continuous- and discrete-time formulations, and large-scale and complex-scope BS cases. In the latter, ordinary least squares... [more]

Thermal efficiency is one of the important indices used to evaluate the operational energy efficiency of hot blast stoves. In this study, a method for calculating the thermal efficiency of hot blast stoves was developed based on simulation results. The working process of top combustion hot blast stoves was numerically simulated through the established 3D fluid flow heat transfer model. The system thermal efficiency of hot blast stoves was calculated according to the simulation data, referring to the Chinese national standard, “measurement and calculation method of the heat balance of blast furnace hot blast stove” (GB/T 32287-2015). In particular, a “segmented calculation and accumulate by time” method was proposed based on the air supply curve to more precisely calculate the heat carried away by the hot blast. The results indicate that when the burning air supply cycles increased from 120 to 240 min, the thermal efficiency showed a trend of first decreasing and then increasing, with t... [more]

Microbial oils can be used as an alternative sustainable and renewable feedstock to fossil reserves for producing lubricants and polyurethane materials. Two oleaginous yeasts were grown on non-detoxified corn stover hydrolysate supplemented with corn steep liquor and mineral medium in shake flasks. Trichosporon oleaginosus DSM 11815 displayed the highest lipid production. This strain was further cultivated in a bench bioreactor, using the same culture medium, under a batch regime. Flow cytometry was used to monitor the T. oleaginosus culture using the dual staining technique (SYBR Green and PI) for cell membrane integrity detection. Values of 42.28% (w/w) and 0.06 g/Lh lipid content and lipid productivity, respectively, were recorded for T. oleaginosus cultivated in the bench bioreactor operated under a batch regime. During the cultivation, most of the yeast cells maintained their integrity. T. oleaginosus has the potential to be used as an oil microbial source for a wide range of indu... [more]

This study aimed to investigate the antioxidant activity and antibacterial effect of total flavonoids from Persicaria hydropiper (L.) Spach (TFs-Ph) and to provide a theoretical basis for the development of drugs for the treatment of pathogenic Escherichia coli and Salmonella spp. of broiler origin. Firstly, the response surface optimization heating reflux method was used to extract TFs-Ph, and the effects of ethanol concentration, solid−liquid ratio, heating reflux time, heating reflux temperature, and number of extraction times on the extraction yield of TFs-Ph were analyzed to determine the optimal extraction conditions. The antioxidant activity of TFs-Ph was determined by measuring the scavenging ability against hydroxyl radicals (•OH), 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide anion (•O2−), and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). The antibacterial effect of TFs-Ph was determined by the disk diffusion method. The results showed that the optimal ex... [more]

Magnetic microwires with amorphous structures can present a unique combination of excellent magnetic softness and giant magnetoimpedance (GMI) effects together with reduced dimensions and good mechanical properties. Such unique properties make them suitable for various technological applications. The high GMI effect, observed in as-prepared Co-rich microwires, can be further optimized by postprocessing. However, unexpected magnetic hardening and a transformation of the linear hysteresis loop into a rectangular loop with a coercivity on the order of 90 A/m were observed in several Co-rich microwires upon conventional annealing. Several routes to improve magnetic softness and GMI effect in Fe- and Co-rich magnetic microwires are provided. We observed that stress annealing could remarkably improve the magnetic softness and GMI ratio of Co-rich microwires. Thus, almost unhysteretic loops with a coercivity of 2 A/m and a magnetic anisotropy field of about 70 A/m are achieved in Co-rich micr... [more]

This paper focuses on the environmental leaching of antimony, a critical mineral, using deep eutectic solvents. Mining residues often contain embedded antimony, posing environmental risks. Deep eutectic solvents, known for being low in toxicity, cost-effective, and environmentally friendly, present a promising avenue for sustainable antimony extraction. The study focuses on optimizing the leaching process through experimental analysis by considering variables such as temperature, time, and percentage of solids. Different deep eutectic solvent (DES) compositions are being studied, including choline chloride with malonic acid, thiourea, and ethylene glycol in different molar ratios, to identify the most effective solvent system for antimony extraction. A sample, originally obtained from mining waste produced via the flotation of antimonite ore, was used to test these three types of DESs. By optimizing the leaching process by changing the ratio of solid and liquid components, as well as t... [more]

Hydrogen storage is a crucial factor that limits the development of hydrogen energy. This paper proposes using a split liner for the inner structure of a hydrogen storage cylinder. A self-tightening seal is employed to address the sealing problem between the head and the barrel. The feasibility of this structure is demonstrated through hydraulic pressure experiments. The influence laws of the O-ring compression rate, the distance from the straight edge section of the head to the sealing groove, and the thickness of the head on the sealing performance of gas cylinders in this sealing structure are revealed using finite elements analysis. The results show that when the gas cylinder is subjected to medium internal pressure, the maximum contact stress on the O-ring extrusion deformation sealing surface is greater than the medium pressure. There is sufficient contact width, that is, the arc length of the part where the stress on the O-ring contact surface is greater than the medium pressure... [more]

Cavitation bubbles commonly exist in shipbuilding engineering, ocean engineering, mechanical engineering, chemical industry, and aerospace. Asymmetric deformation of the bubble occurs near the boundary and then has strong destructiveness, such as high amplitude loading. Therefore, the research on non-spherical deformation is of great significance, and the objective of this paper is to investigate the non-spherical collapse dynamics of laser-induced cavitation bubbles when near different boundaries. In this study, experimental data, such as the bubble pulsation process and bubble surface velocity distribution, were obtained by high-speed camera techniques and full-field velocity calculations. Near the different boundaries, the results show that the bubbles appeared to have different collapse shapes, such as near-hemispherical, near-ellipsoidal, near-cone, and near-pea shapes, and the surface velocity distribution is extremely non-uniform. When the bubble near the free surface or rigid b... [more]

In 2019, one of the Editorial Staff of the MDPI journal Processes, sent me an email informing me that I was being invited to join the Editorial Board of the journal, a proposal that I accepted [...]

In gas cap reservoirs underlain by bottom water, the connection between the reservoir and the aquifer leads to an increasing invasion of bottom water as reservoir development progresses. The average formation pressure of the reservoir will change, and the separated phase recovery of the gas cap reservoir with bottom water will be affected by the change in the average formation pressure. The traditional average formation pressure calculation formulas do not consider the water influx, so the accurate calculation of separated recovery cannot be obtained by those calculation methods. The development of gas cap reservoirs with bottom water presents several challenges, including the simultaneous production of oil and gas, undetermined rates of bottom water influx, and uncertain formation pressure and gas-to-oil ratios. These factors contribute to substantial discrepancies between theoretical calculations and actual observations. A more accurate and comprehensive approach is required to addre... [more]

Nodular iron plays a crucial role in various industries, especially in large-scale applications such as gearboxes. Ensuring that nodular iron remains free from oil leakage and that contact surfaces are properly aligned is essential, given its operational requirements. Achieving flat contact faces through precise machining is therefore of utmost importance. As surface roughness and flatness are closely linked, it is vital to investigate the machining process parameters involved. This study focuses on addressing surface quality issues with EN-GJS-600-3 cast iron by optimizing machining parameters. CMM measurements were utilized to analyze the relationship between surface roughness and flatness, with a surface profile used to assess flatness. Furthermore, a new 2D surface roughness estimation method (2D-SRET) was created and tested with experimental data in order to improve the precision of assessing the discrete flat surface machining procedure.

Although the calcination-based activation of coal gangue is important for its valorization in the form of cementitious materials, the related works mainly focus on high-quality coal gangue, neglecting its low-quality counterpart. To bridge this gap, we herein conducted the pilot-scale suspension calcination of low-quality coal gangue; explored the effects of calcination temperature, particle size, and O2 content on the phase composition of the calcined product, kaolinite decomposition, decarbonization, and silica/alumina dissolution; and evaluated calcination-product-based cementitious materials. Under optimal conditions (temperature = 875−900 °C; particle size = 39.71−46.84 μm; and O2 content = 12−14%), the carbon content of the calcined product equaled 1.24−1.87 wt%, and the dissolution rates of activated alumina and silica were 77.6−79.5% and 49.4−51.1%, respectively. The 28 d compressive strength (50.8−55.7 MPa) and true activity index (98.8−108.4%) of the cementitious material pre... [more]

The inherent volatility of PV power introduces unpredictability to the power system, necessitating accurate forecasting of power generation. In this study, a machine learning (ML) model based on Gaussian process regression (GPR) for short-term PV power output forecasting is proposed. With its benefits in handling nonlinear relationships, estimating uncertainty, and generating probabilistic forecasts, GPR is an appropriate approach for addressing the problems caused by PV power generation’s irregularity. Additionally, Bayesian optimization to identify optimal hyper-parameter combinations for the ML model is utilized. The research leverages solar radiation intensity data collected at 60-min and 30-min intervals over periods of 1 year and 6 months, respectively. Comparative analysis reveals that the data set with 60-min intervals performs slightly better than the 30-min intervals data set. The proposed GPR model, coupled with Bayesian optimization, demonstrates superior performance compar... [more]

In response to the urgent need for efficient pneumonia diagnosis—a significant health challenge that has been intensified during the COVID-19 era—this study introduces the RCGAN-CTL model. This innovative approach combines a coupled generative adversarial network (GAN) with relativistic and conditional discriminators to optimize performance in contexts with limited data resources. It significantly enhances the efficacy of small or incomplete datasets through the integration of synthetic images generated by an advanced RCGAN. Rigorous evaluations using a wide range of lung X-ray images validate the model’s effectiveness. In binary classification tasks that differentiate between normal and pneumonia cases, RCGAN-CTL demonstrates exceptional accuracy, exceeding 99%, with an area under the curve (AUC) of around 95%. Its capabilities extend to a complex triple classification task, accurately distinguishing between normal, viral pneumonia, and bacterial pneumonia, with precision scores of 89... [more]

CO2 geological storage combined with deep saline water recovery technology (CO2-EWR) is one of the most effective ways to reduce carbon emissions. Due to the complex structural features, it is difficult to use CO2-EWR technology in Huaiyin Sag, Subei basin, East China. In this study, the multi-source information superposition evaluation technology of GIS was utilized for the selection of CO2 storage sites and water displacement potential target areas in this area, which mainly focused on the sandstone reservoirs of Cretaceous Pukou Formation. Based on the results, a three-dimensional injection−extraction model was established. Various scenarios with different production/injection well ratios (PIR) were simulated. Research has shown that the suitability of the surrounding site of Huaiyin Power Plant can be divided into two levels: relatively suitable and generally suitable; the area in the generally suitable level accounts for more than 80%. At a PIR of 1, CO2 is distributed asymmetrica... [more]

Biowaste, which often accounts for more than 50% of municipal waste, is an environmental problem if disposed of improperly in landfills but has great potential to achieve the recycling targets set out in Directive (EU) 2018/851. Despite the knowledge in theory and practice about the processing of biowaste and the benefits of recycling, there is a lack of methodological approaches in describing the process of aerobic biodegradation in a concise and suitable way for decision makers, environmental engineers, and project designers. This paper presents how basic data on the properties of biowaste can be used, using theoretical models, to determine basic indicators of the dynamics and material balance of the process. The maximum rate of CO2 generation on the 4th day was Rm = 45.3 g/d, with the potential of available, readily biodegradable components of the biowaste sample of P = 526 g CO2/kg VS. A substrate conversion of 51.7% was achieved in the bioreactor by the 17th day of treatment. The... [more]

Cold atmospheric pressure plasma (CAP) has attracted increased interest in recent years for possible biomedical, environmental and agricultural applications. A wide range of cold plasma treatment effects is observed in agricultural applications, like effects on the seed germination and seedling growth, but more systematic investigations are needed. The aim of this study was to identify the most appropriate combinations of the plasma source and duration of treatment positively affecting seed germination. In addition, the effect of cold plasma on the seedling growth and osmotic stress tolerance was studied. The seeds of three Bulgarian durum wheat cultivars were treated with cold plasma in twelve variants. The results obtained were processed statistically via two-way ANOVA. The treatment of seeds with a plasma torch for 20 s and the treatment with underwater diaphragm discharge for 5 min when the seeds were placed in both cameras in two different positions (relative to the electrodes bet... [more]