Currently, there are problems such as weak training purpose, poor training effect and backward auxiliary decision-making means in college physical education. In this paper, we first construct a ...college sports training management decision-making system based on Multi-Agent and adopt the blackboard model to realize the communication between Agents. The training management decision-making agent system uses the maximum information entropy model to identify the benefits and drawbacks of executing college sports training management decisions. Secondly, feature selection is carried out through the correlation filter (CFS), and the best priority search method is used to obtain the required subset of features. Finally, the reliability of the college sports training management decision-making agent system was verified by testing experiments. The results show that the inter-rater of the system is 0.920.95, and the intra-rater is 0.94, reflecting the good reliability and practicality of the training management decision-making Agent system. This study enhances the effectiveness of sports training management to some extent, and it also serves as a valuable reference for the development of similar systems.
In this paper, we propose an optimized power distribution method for hybrid electric energy storage systems for electric vehicles (EVs). The hybrid energy storage system (HESS) uses two isolated ...soft-switching symmetrical half-bridge bidirectional converters connected to the battery and supercapacitor (SC) as a composite structure of the protection structure. The bidirectional converter can precisely control the charge and discharge of the SC and battery. Spiral wound SCs with mesoporous carbon electrodes are used as the energy storage units of EVs. Under the 1050 operating conditions of the EV driving cycle, the SC acts as a “peak load transfer” with a charge and discharge current of 2isc~3ibat. An improved energy allocation strategy under state of charge (SOC) control is proposed, that enables SC to charge and discharge with a peak current of approximately 4ibat. Compared with the pure battery mode, the acceleration performance of the EV is improved by approximately 50%, and the energy loss is reduced by approximately 69%. This strategy accommodates different types of load curves, and helps improve the energy utilization rate and reduce the battery aging effect.
Recently observation of random walks in complex environments like the cell and other glassy systems revealed that the spreading of particles, at its tails, follows a spatial exponential decay instead ...of the canonical Gaussian. We use the widely applicable continuous time random walk model and obtain the large deviation description of the propagator. Under mild conditions that the microscopic jump lengths distribution is decaying exponentially or faster i.e., Lévy like power law distributed jump lengths are excluded, and that the distribution of the waiting times is analytical for short waiting times, the spreading of particles follows an exponential decay at large distances, with a logarithmic correction. Here we show how anti-bunching of jump events reduces the effect, while bunching and intermittency enhances it. We employ exact solutions of the continuous time random walk model to test the large deviation theory.
The central North China Plain (NCP) is one of the rapidly developing regions in China which has a great potential for ground source heat pump (GSHP) system applications. However, the ground thermal ...property, which is a prerequisite for GSHP system design, has been insufficiently investigated. In this paper, the ground thermal conditions including ground temperature and thermal conductivity are characterized in three representative hydrogeological regions in the NCP area: the piedmont alluvial plain, the central alluvial plain, and the coastal plain. Results show that the geothermal gradient below 40 m in depth in this area ranges from 0.018 °C/m to 0.029 °C/m. Although the thermal conductivity measured by soil samples differs slightly among the three regions, parameters in the piedmont plain have a larger variability than in the central and coastal plain due to the significant heterogeneity of the lithology. Thermal conductivity measured by the thermal response test (TRT) ranges between 2.37 and 2.68 W/(m·K) in the piedmont plain and varies between 1.35 and 1.94 W/(m·K) in the central and coastal plain, indicating that the piedmont plain has a higher potential for shallow geothermal exploitation than other two sub-areas. Comparing the TRT with laboratory measurements, the thermal conductivity obtained by the TRT is greater than that of the lab measurements in the piedmont plain due to the TRT outputs including the effects of groundwater flow. Therefore, the TRT is highly recommended to estimate the effective thermal conductivity of the ground in the piedmont plain, while laboratory and field tests are both suitable methods for the determination of thermal conductivity in the central and coastal plains.
Graptolite reflectance was thought to be one of the most useful thermal maturity indicators for graptolite-bearing sediments, however, the relationship between graptolite reflectance and vitrinite ...reflectance is not well-established. Graptolites, especially in the Wufeng–Longmaxi Formations from the Ordovician to Silurian of South China, have been mistaken for vitrinite-like particles or solid bitumen, which results in inconsistent data on the thermal maturity. In this paper, we have employed optical microscope techniques to describe the detailed optical characteristics of graptolites and solid bitumen in the Wufeng–Longmaxi Formations. Laboratory simulation of maturation was used to determine the relationship between graptolite reflectance and vitrinite reflectance.
The organic constituents in the Wufeng–Longmaxi Formations are mainly composed of graptolites and solid bitumen. Granular and non-granular graptolites were observed in the Wufeng–Longmaxi Formations, with non-granular as the most common texture. Solid bitumen can be distinguished from non-granular graptolites by its coarse surface, weaker anisotropy, and lower random reflectance. The combination of non-polarized and polarized light is very helpful to distinguish solid bitumen from graptolite. For comparison, organic material from the early Ordovician Alum Shale Formation of Sweden and Estonia was also studied. The macerals of the Alum shales are mainly composed of lamalginites, mineral-bituminous groundmasses, graptolites, and solid bitumen. The major textures of the graptolites in the Sweden and Estonia sediments are non-granular and granular, respectively.
Both non-granular graptolite and vitrinite reflectances display a systematic increase with the increase of heating temperature and time. The granular graptolites in the Estonian sample were gradually changed to non-granular graptolites following laboratory simulated maturation, indicating that granular graptolites can transform into non-granular graptolites with maturation. Solid bitumen in the Wufeng–Longmaxi Formations was derived from the solid residue of kerogen and/or post-oil bitumen. The graptolite random reflectance is a better thermal maturity indicator than graptolite maximum reflectance and is more precise due to the smaller standard deviation. Several equations are proposed to determine the thermal maturity of the graptolite-bearing sediments based on graptolite random reflectance, graptolite maximum reflectance and solid bitumen random reflectance.
•The relationship between graptolite reflectance and vitrinite reflectance has been determined.•The random reflectance of graptolite is a more suitable rank indicator.•The granular graptolites can transform into non-granular graptolites with maturation.•Solid bitumen was derived from the solid residue of kerogen and/or post-oil bitumen.
High-performance joining especially brazing has been highly expected in the manufacture or maintenance of single crystal blades. In this paper, a Ni-40Cr-10Ta (at.%) alloy was developed as filler ...material for single crystal superalloys. High-performance brazing of DD5 superalloy was achieved. The joints brazed at 1260 °C contained an isothermal solidification zone (ISZ) with “γ + γ′” structure and an athermal solidification zone (ASZ) composed of γ, γ', γ/γ′-eutectics, TaCr2 and TaC. Unlike the conventional filler materials with melting point depressants of B and Si, the Ni-Cr-Ta filler material was free of B and Si, and thus the resulting joints contained no B-rich and Si-rich compounds and eutectics with low melting points, which enhanced the brazed joint performance. The tensile strength at 980 ℃ of the heat-treated joints reached 654 MPa, which is 88.5 % that of the base metal.
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•A novel interface-strengthened brazing process for the joining of carbon/carbon composites and nickel-based superalloys is presented.•By first planting molybdenum fibers on the ...joining surface, the carbon/carbon composite is successfully brazed to the nickel-based superalloy.•Robust joints with molybdenum fibers extending across the joining interface between the C/C substrate and the brazing layer are obtained.•The maximum shear strength of the joint is 60 MPa, which 2.14-times that of the joint without molybdenum-fiber-planting.
The robust and reliable joining of carbon/carbon (C/C) composites and metals has important application value in the aerospace field. However, the low interface bonding strength when joining the two dissimilar materials remains a persistent problem and leads to low joint strength. In this work, a novel interface strengthened brazing process has been developed for joining a C/C composite and a nickel-based superalloy (GH3044). Before joining, high-strength molybdenum (Mo) fibers are planted on the surface of the C/C composite, then the fiber-treated C/C composite is brazed to the GH3044 superalloy using a BNi-2 filler. The results show that a sound joint with robust Mo fibers crossing the interface between the C/C substrate and the brazing layer is obtained. Owing to the pinning effect of the Mo fibers, the joining interface area is increased and cracking is effectively prevented. As a result, the bonded joint exhibits excellent mechanical properties. The maximum shear strength of the joint was measured to be 60 MPa, which is 2.14-times that of the joint without fiber-planting. The maximum three-point bending strength of the joint was measured at 31 MPa, which is 2.58-times that of the joint without fiber-planting.
The current global production of plastics is over 300 million tons, 20% of which is produced in China. It has been estimated that about 90% of the discarded plastics are not recycled. China was the ...world’s leading importer of waste plastics, while since January 1, 2018, China’s import ban on waste plastics has been put into force, which has had a far-reaching effect on global plastic production and solid waste management. Southeast Asian countries like Malaysia have replaced China as the leading importer of plastic wastes. As the main exporter of waste plastics, EU has released strategy and initiative about plastics to restrict the use of micro plastics and single-use plastics. Meanwhile main European counties like UK, German and France have also taken own active measures to realize the control of packaging waste and non-recycled plastic and the recycling of plastic wastes in several years. As For the US, some areas such as Seattle and San Francisco have positively responded to the global trend of plastic ban. However, the controversy over “plastic restriction” in the whole state obstructed the promulgation and implementation of the national plastic ban. On the whole, major companies and more than 60 countries all over the world have introduced levies or bans to combat single-use plastic wastes. The Chinese government began to rectify the domestic waste plastics market and the Ministry of Industry and Information Technology of China has clarified the threshold of waste plastic treatment capacity for key enterprises. In addition to landfill, direct recovery and waste to energy processes are the main disposal methods of waste plastics. Thermoplastics like PE, PP and PET that are sorted out from the waste stream by citizens can be directly recycled to the primary material. The mixed waste plastics can be used as fuel in waste to energy plants, or as feedstock to pyrolysis plants that transform them to high value-added oil or chemical materials, which are more promising disposal methods of waste plastics.
This paper proposes a recursive delta-operator-based subspace identification method with fixed data size. The majority of existing subspace identification methods are constrained to discrete-time ...systems because of the disparity in Hankel matrices. Additionally, due to the storage cost, LQ-factorization and singular value decomposition in identification methods are best suited for batch processing rather than online identification. The continuous-time systems are transformed into state space models based on the delta-operator to address these issues. These models approach the original systems when the sampling interval approaches zero. The size of the data matrices is fixed to reduce the computing load. By fading the impact of past data on future data, the amount of data storage can be decreased. The effectiveness of the proposed method is illustrated by the continuous stirred tank reactor system.
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