Nine-Axis Sensor for Athlete Physical Training Load Characteristics

In order to understand the characteristic data of athletes’ training load, a method based on nine-axis sensor was proposed. Twenty-seven male college athletes were tested twice with a time interval of more than 48 hours. In part 1, participants take the 1 Repetition Maximum (1RM) test. The results show that maximum strength is one of the basic factors to develop the output power of athletes. In the process of skeletal muscle contraction, the curve of speed, force, and power is closely related. When the external load is 10%∼70%, the average power increases with the increase in the average force, it increases with the decrease in the average speed, and at 70%1RM, the average power reaches the peak and then decreases at an inflection point. It is proved that the accurate weight ratio of strength training is the basis of winning athletes, the focus of high level physical coach, and the premise of scientific sports training.

Optimal Sizing of Stand-Alone Microgrids Based on Recent Metaheuristic Algorithms

Scientists have been paying more attention to the shortage of water and energy sources all over the world, especially in the Middle East and North Africa (MENA). In this article, a microgrid configuration of a photovoltaic (PV) plant with fuel cell (FC) and battery storage systems has been optimally designed. A real case study in Egypt in Dobaa region of supplying safety loads at a nuclear power plant during emergency cases is considered, where the load characteristics and the location data have been taken into consideration. Recently, many optimization algorithms have been developed by researchers, and these algorithms differ from one another in their performance and effectiveness. On the other hand, there are recent optimization algorithms that were not used to solve the problem of microgrids design in order to evaluate their performance and effectiveness. Optimization algorithms of equilibrium optimizer (EQ), bat optimization (BAT), and black-hole-based optimization (BHB) algorithms have been applied and compared in this paper. The optimization algorithms are individually used to optimize and size the energy systems to minimize the cost. The energy systems have been modeled and evaluated using MATLAB.

Uncovering Hidden Factors in Electricity Consumption Based on Gaussian Mixture Estimation

Load characteristics play an essential role in the planning of power generation and distribution. Various undiscovered factors, which could be socioeconomic, geographic, or climatic, make it possible to describe the electricity demand by a multimodal distribution. This letter proposes a novel method based on multimodal distributions to characterize the hidden factors in electricity consumption. Consequently, a new approach is developed to evaluate the impact of the underlying factors of electricity consumption. Some quantifiable and predictable factors are analyzed in developing multimodal distribution to describe the expected demand. Simulations based on synthetic and real-world data have been conducted to demonstrate the usefulness and robustness of the proposed method.

Research on Load Characteristics of Axle-Box Bearing Raceway under Wheel-Rail Excitation

With the increasing speed of high-speed trains, the service conditions of axle-box bearing system worsen, and meanwhile, the dynamic performance of the axle-box bearing directly affects the operational safety. However, the dynamic interactions of the axle-box bearing in the traditional vehicle-track system are often ignored. In this paper, a vehicle-track coupling dynamic model considering axle-box bearing has been built, and the effectiveness of the model is proved by field tests. Dynamic performance of the axle-box bearing has been analyzed and discussed through numerical simulations under different working conditions. Comparing the roller-raceway contact load characteristics under different working conditions, results show that the peak values of roller-outer raceway contact load with wheel-polygonal excitation are basically the same with those without wheel-rail excitation. However, most of the peak values of roller-outer raceway contact force under track irregularity and comprehensive excitation conditions are far greater than those under wheel-polygonal excitation and no wheel-rail excitation conditions, which indicates that the impact of track irregularity on the contact load is dominant.

High-cycle and very-high-cycle fatigue behavior of a stainless steel for air-conditioning compressor valve plates

PurposeThe investigations could guide the structural design and fatigue life prediction of air-conditioning compressor valve plates.Design/methodology/approachThe High-Cycle Fatigue (HCF) and Very-High-Cycle Fatigue (VHCF) behaviors of stainless steel used for air-conditioning compressor valve plates were investigated. Monotonic and cyclic loading conditions were designed to explore the fatigue responses according to the load characteristics of the structure.FindingsThe crack initiation can be observed as the arc-shaped cracks at both sides of specimens and Y-shaped crack bifurcation in the specimens. Moreover, the middle section and the cracks at both ends are not connected to the surface of the specimen. The stress-life results of the materials under two directions (vertical and horizontal) were provided to examine the difference in fatigue strength.Originality/valueMonotonic and cyclic loading conditions were designed to explore the fatigue responses according to the load characteristics of the structure. Based on the experimental data, the results indicate that specimens under cyclic loading conditions could demonstrate better mechanical performance than static loadings.

Effect of Different Intensity Outdoor Tennis Training on Cardiac Load

Starting from the outdoor tennis competition, this paper studies the load characteristics of tennis competition through the experimental test of outdoor tennis players. This paper mainly adopts four research methods: literature, experimental test, mathematical statistics and logical analysis. This paper analyzes the load characteristics of outdoor tennis players in singles through experiments on the characteristics of competition time, the changes of center rate in the process of competition and the changes of creatine kinase, blood urea and urinary protein before and after competition. The results showed that the content of creatine kinase in blood increased significantly and the protein in urine increased significantly. This shows that outdoor tennis competition is more intense. The increase of blood urea after competition shows that there is a certain load in outdoor tennis competition, but the load is relatively small. The small load is mainly due to the short time of outdoor tennis competition, so the content of blood urea will not increase significantly.