Given the significant greenhouse effect of SF6, the C4F7N-CO2-O-2 mixture has been identified as one of the most promising eco-friendly arc-extinguishing gases. Switching arcs typically exhibit pronounced non-local th...
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Given the significant greenhouse effect of SF6, the C4F7N-CO2-O-2 mixture has been identified as one of the most promising eco-friendly arc-extinguishing gases. Switching arcs typically exhibit pronounced non-local thermodynamic equilibrium (NLTE) phenomena in the peripheral regions and at the current zero-crossing point, thereby influencing the thermophysical properties of the plasma. To investigate the impact of NLTE conditions, the thermodynamic properties and transport coefficients of two-temperature (2-T) C4F7N-CO2-O-2 plasma were calculated under the local chemical equilibrium assumption. The results indicate that NLTE conditions significantly affect the properties of the mixture by altering its composition andparticle energy, often having a more substantial impact than pressure variations. The generation of CO plays a critical role in shaping the thermodynamic and transport parameters of the plasma due to its molecular stability, particularly under non-equilibrium states. To maximise the arc-extinguishing performance of the gas, recommended oxygen mixing ratios are proposed. The results provide fundamental data for 2-T magnetohydrodynamic modelling of C4F7N gas mixtures in arc simulations.
High reliability applications in dense access scenarios have become one of the main goals of 6G *** solve the access collision of dense Machine Type Communication(MTC)devices in cell-free communication systems,an inte...
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High reliability applications in dense access scenarios have become one of the main goals of 6G *** solve the access collision of dense Machine Type Communication(MTC)devices in cell-free communication systems,an intelligent cooperative secure access scheme based on multi-agent reinforcement learning and federated learning is proposed,that is,the Preamble Slice Orderly Queue Access(PSOQA)*** this scheme,the preamble arrangement is combined with the access *** preamble arrangement is realized by preamble slices which is from the virtual preamble *** access devices learn to queue orderly by deep reinforcement *** orderly queue weakens the random and avoids collision.A preamble slice is assigned to an orderly access queue at each access *** orderly queue is determined by interaction information among multiple *** the federatedreinforcement learning framework,the PSOQA scheme is implemented to guarantee the privacy and security of ***,the access performance of PSOQA is compared with otherrandom contention schemes in different load *** results show that PSOQA can not only improve the access success rate but also guarantee low-latency tolerant performances.
Antioxidants, both glutathione (GSH) and astaxanthin (AX), possess beneficial applications in animal growth and antioxidant properties. In this study, three experimental diets with isoproteic and isolipidic were formu...
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Antioxidants, both glutathione (GSH) and astaxanthin (AX), possess beneficial applications in animal growth and antioxidant properties. In this study, three experimental diets with isoproteic and isolipidic were formulated, the control diet (CON), the control diet added with 0.03% Carophyll Pink (contains 10% AX), the control diet added with 0.67% glutathione-rich yeast hydrolysate (GYH, contains 5% GSH). The effects of AX and GYH on the growth performance, antioxidant capacity and lipid metabolism of Litopenaeus vannamei (0.36 +/- 0.01 g) were compared. After an 8-week feeding experiment, shrimp growth and intestinal morphology showed significantly better performance in the GYH group. Both dietary AX and GYH regulated the expression levels of genes related to lipid metabolism, increased antioxidant enzyme activities and total antioxidant capacity of shrimp andreduced haemolymph malondialdehyde and hepatopancreas reactive oxygen species production. Compared with the CON and GYH groups, dietary AX significantly increased the redness (a*) and yellowness (b*) values of cooked shrimp. Based on the evaluation of the above results, AX and GYH were comparable in terms of antioxidant performance, and AX was superior in improving the red body colour of shrimp, but GYH has more significant advantages in promoting shrimp growth and intestinal development. Therefore, supplementation with GYH or AX in diet presents specific benefits to the growth, body colour and antioxidant of L. vannamei.
Life cycle assessment (LCA) is used to quantitatively analyze the energy consumption and environmental impact of primary aluminum production in china, the United States, and Europe, as well as global average. The resu...
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Life cycle assessment (LCA) is used to quantitatively analyze the energy consumption and environmental impact of primary aluminum production in china, the United States, and Europe, as well as global average. The results indicate that electricity and fuel contribute more than 60% of the environmental impact of bauxite mining;steam is the greatest contributor to the environmental impact of alumina production by the Bayer process, with a result exceeding 35%;and electricity contributes >50% of the environmental impact of aluminum electrolysis. The environmental impact of primary aluminum production in china is 1.2 times the global average. The contributions of the three stages of primary aluminum production to the total environmental impact of the process in china are, in descending order, aluminum electrolysis (64.33%), alumina production (33.09%), and bauxite mining (2.58%). If the proportion of thermal power in the electricity source structure is reduced from 60% to 0%, the contribution of electricity to the environmental impact of primary aluminum production will decrease from 38% to 2%, and the total environmental impact will decrease by 73%. Therefore, energy conservation and emissions reduction can be realized through the optimization of the power generation structure, adoption of clean energy production, and improvement of the heat utilization rate in production processes.
This paper presents a thermal properties analysis model of angular contact ball bearings considering thermal-mechanical coupling structure deformations. The correlation between the assembly state and structure flexibl...
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This paper presents a thermal properties analysis model of angular contact ball bearings considering thermal-mechanical coupling structure deformations. The correlation between the assembly state and structure flexible deformations for the shaft-bearing-pedestal system is derived, and an improved transient thermal network model considering cage guiding type and grease heat transfer process is constructed. The influencing mechanism of bearing thermal properties is revealed, and the variations of structure deformations and service performance compared to those cases without considering thermal effect are explored. results indicated that the deformations of the shaft and bearing ring are more sensitive to the thermal effect, which is significantly greater than those cases without considering the thermal effect. The thermal expansion induced by temperature rise intensifies the bearing structure deformations, anddecreases bearing clearance and the design contact angle. The bearing deformations are positively correlated with the rotation speed and external loads, and the bearing thermal characteristics can be optimized by properly adjusting the assembly state of the rotor-bearing system.
The cavitation model is essential in simulating cavitation flow characteristics of injector nozzles, with its accuracy directly impacting simulation precision. This paperdeveloped a quantitative relationship between ...
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The cavitation model is essential in simulating cavitation flow characteristics of injector nozzles, with its accuracy directly impacting simulation precision. This paperdeveloped a quantitative relationship between critical cavitation pressure, turbulent kinetic energy, and shear stress, and introduced a modified cavitation model that considers turbulence effects. A simulation study was conducted on the fuel flow characteristics inside the nozzle of a high-pressure common rail diesel injector with seven nozzle holes. The results indicate that compared to the original model, the cavitation development calculated by the modified model is enhanced at different injection pressures. In terms of axial distribution, cavitation inside the nozzle hole increases, but the impact on cavitation of different intensities varies, with the development of moderate to low-intensity cavitation being promoted, while strong cavitation is inhibited. In terms of radial distribution, the intensity of cavitation on the upper wall inside the nozzle hole increases, which is caused by the higher mass transferrate near the upper wall at the nozzle hole inlet. As the injection pressure increases from 120 to 240 MPa, the change rate of cavitation volume ratio inside the nozzle holes calculated by the original and modified models increases from 5.1% to 9.7%. It is necessary to use the modified model for the calculations of gas/liquid two-phase flow within the nozzle hole, especially at high injection pressure.
A time-fractional diffusion problem with a Caputo time-fractional derivative of order alpha is an element of (0, 1) is considered, the solution of which is typically weakly singular at the initial time. For this probl...
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A time-fractional diffusion problem with a Caputo time-fractional derivative of order alpha is an element of (0, 1) is considered, the solution of which is typically weakly singular at the initial time. For this problem, we give an H-1-norm analysis of the stability and convergence of an integral-averaged L1 method on nonuniform time meshes. The averaging of the L1 scheme that we use is known as the L1(+) or L1rline> scheme. A new positive definiteness result for the integral-averaged L1 fractional-derivative operator is established. It improves the previous positive definiteness results in the literature and plays an important role in the analysis of H-1-norm error of the integral-averaged L1 method. The H-1-norm stability holds for the general nonuniform time meshes, while the H-1-norm convergence is proved for the time graded meshes and the H-1-norm convergence order in time is min{3 + alpha, gamma alpha}/2 for all alpha is an element of (0, 1), where gamma >= 1 is the mesh grading parameter. Two full discretization methods using finite differences and finite elements in space are considered. The theoretical results are illustrated by numerical results.
despite the adverse impacts of occupational fatigue such as accidents and injuries in the manufacturing industry, it has not been systematically examined in the literature on production scheduling. In this paper, we i...
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despite the adverse impacts of occupational fatigue such as accidents and injuries in the manufacturing industry, it has not been systematically examined in the literature on production scheduling. In this paper, we integrate the classic bio-mathematical fatigue prediction model from the brain science literature into the simple single machine scheduling problem with sequence-dependent setup times. Then, we formulate the problem as a mixed-integer linearprogramming model and propose an adaptive large neighborhood search heuristic. The effectiveness of the heuristic is numerically validated through real cases. Finally, we argue that considering bio-mathematical fatigue prediction can lead to safer production schedules, notably reducing the fatigue working hours in ourreal case.
Previous work showed that animals have demonstratedremarkable adaptability by actively integrating into urban environments. However, there is no essential difference between urban andrural areas but food availabilit...
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Previous work showed that animals have demonstratedremarkable adaptability by actively integrating into urban environments. However, there is no essential difference between urban andrural areas but food availability. The behavioral mechanisms and processes by which animals adapt to cities still require further experimental validation. In this study, field surveys of the flight initiation distance (FId) of black-headed gulls (Chroicocephalus ridibundus) were performed at three scenic sites in Kunming City, Yunnan, southwest china. Ourresults showed that, within the same area, the FId of black-headed gulls was significantly shorter in areas with increased human activity. Moreover, in areas with earlier human contact, black-headed gulls showed shorter FId. The FIddata were further analyzed by a multilayer perceptron regression model with a neural network (ANN-MLP) approach to delineate FId thresholds for black-headed gulls in different human disturbance spots. The analysis revealed that black-headed gulls exhibit a high degree of behavioral flexibility in cities, with food availability playing a keyrole in increasing the birds' tolerance to humans. These findings highlight the significant impact of human behaviors, such as feeding, on wildlife behavior patterns. Understanding this mechanism is essential for understanding the coexistence of humans and wildlife. The establishment of FId models for black-headed gulls will provide new possibilities and tools for animal behaviorresearch.
The objective of this study was to analyse the difference in sensory flavour and volatile compounds among the three processing methods of soy whey, as well as to establish an evaluation model representing the correlat...
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The objective of this study was to analyse the difference in sensory flavour and volatile compounds among the three processing methods of soy whey, as well as to establish an evaluation model representing the correlation between sensory flavour and volatile compounds. The results showed that the soy whey produced by the boiling-to-filtering method (BFM) exhibited a higher total soluble solid (TSS) content and total flavonoid content (TFC) compared to that of the repeated boiling-to-filtering method (rBFM) and the filtering-to-boiling method (FBM), while rBFM soy whey showed a higher total protein content (TPC). The sensory analysis showed that the FBM soy whey exhibited an intense beany flavour and grease odour. The SPME/GC-MS results showed that FBM soy whey exhibited more categories and higher contents of flavour compounds, particularly for alcohols and aldehydes. 1-Octen-3-ol, n-hexanol, hexanal and nonanal were the main volatile compounds influencing soy whey with different processing methods. The evaluation model revealed that the beany flavour was close to FBM soy whey and highly correlated with 1-octen-3-ol, n-hexanol, hexanal, heptanal and 2-ethyl furan. (E, E)-2,4-Heptadienal, (E, E)-2,4-nonadienal and octanal were close to FBM and highly correlated with grease and bean fragrance. decanal, ethyl caproate and ethyl caprylate were highly correlated with the floral aroma and close to FBM soy whey. Sweet and fruity aromas were associated with rBFM soy whey and highly correlated with 3-methyl butanal, (E)-2-nonenal and nonanal. The milk aroma was close to BFM soy whey and highly correlated with 2-ethylfuran, decanal, ethyl caprylate and ethyl caproate. Overall, rBFM and BFM soy whey contained higher levels of protein and flavonoids and exhibited less beany flavour, potentially offering greater nutritional value. In contrast, the FBM soy whey exhibited a higher content of volatile flavour compounds, especially 1-octen-3-ol, n-hexanol, hexanal and 2-ethyl furan.
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