This article examines a simulated collision between a car and a cyclist, assessing the trajectory of the cyclist’s movement after the impact, namely the throwing distances and angles of the cyclist ...and bicycle. Information about the car and cyclist models used for the study is provided. Special software PC CRASH 8.1 for the analysis and reconstruction of traffic accidents was used to simulate a car–cyclist collision. Simulations of car–cyclist collisions were carried out, with different speeds for the car and the cyclist, and locations at the time of the impact. The movement of a bicycle after a crash tends to be irregular and is dependent on various parameters that are usually not possible to evaluate. Therefore, the parameters of the movement of the bicycle after the collision (the throwing angle and the distance) usually do not allow determination of the speed of the car before the accident. The movement of the cyclist after impact was more informative for determining the speed of the car before the accident. For example, when there was an angle of 30°, 60°, or 90° between the longitudinal axes of the car and the cyclist, there was a clear dependence between the speed of the car and the cyclist’s throwing distance, and usually also between the speed of the car and the cyclist’s throwing angle. Thus, in such cases, it is possible to determine approximately the initial speed of the car before the collision, based on the trajectory of the cyclist’s movement after the impact, namely his throwing distance and angle. In cases of real traffic accidents, with knowledge of the location of the car–cyclist collision and the position of the cyclist after the traffic accident, the speed of the car before the accident can be determined according to the abovementioned dependencies. Thus, the proposed methodology could be used in the reconstruction and examination of traffic accidents.
This paper discusses the issues of creating a ballistic facility for use in laboratory conditions and achieving throwing speeds of up to 2000 m/s for massive objects. The design of the facility was ...proposed and the results of the analytical calculation of the achieved speeds were presented. The verification of the analytical calculation and the results of experiments on the prototype ballistic facility was done.
Throwing speed is likely a key determinant of shoulder-specific load. However, it is difficult to estimate the speed of throws in handball in field-based settings with many players due to limitations ...in current technology. Therefore, the purpose of this study was to develop a novel method to estimate throwing speed in handball using a low-cost accelerometer-based device. Nineteen experienced handball players each performed 25 throws of varying types while we measured the acceleration of the wrist using the accelerometer and the throwing speed using 3D motion capture. Using cross-validation, we developed four prediction models using combinations of the logarithm of the peak total acceleration, sex and throwing type as the predictor and the throwing speed as the outcome. We found that all models were well-calibrated (mean calibration of all models: 0.0 m/s, calibration slope of all models: 1.00) and precise (R2 = 0.71-0.86, mean absolute error = 1.30-1.82 m/s). We conclude that the developed method provides practitioners and researchers with a feasible and cheap method to estimate throwing speed in handball from segments of wrist acceleration signals containing only a single throw.
Abstract
At present, the mechanization of shrimp culture in China is still low, and most of them are artificially fed. Artificial feeding is not only labor-intensive, but also has the disadvantages ...of uneven feed throwing. In this paper, a feeding device for Penaeus Vannamei breeding pond is designed, which mainly includes guide trolley, support body, feeding rod, storage plate and storage bucket, the feeding efficiency of Penaeus Vannamei is improved.
An organic additive, gentian violet (GVT), is explored for the first time as a novel leveler with excellent property in through-holes (THs) metallization of Cu electronic plating in acidic medium for ...printed circuit board (PCB) applications. Studies of galvanostatic measurements with a platinum rotation disk electrode and density functional theory calculations demonstrate that the GVT behaves the fundamental leveler's characteristics of mass transfer adsorption, and displays a strong inhibition effect on electro-reduction of cupric ions at high rotating rate. Although the adsorption ability of GVT on Cu surface is weaker than that of commercial leveler Janus Green B (JGB), the potential difference of cupric ion reduction between low and high rotating rates is larger in case of GVT than that of JGB at same current density. Cyclic voltammetry measurements indicate that the Cu amounts of cathodic deposition and that of anodic stripping tend to the same at both low and high rotating rates when GVT, Cl−, polyethylene glycol (PEG) and bis-(sodium sulfopropyl)-disulfide (SPS) coexist in the solution, demonstrating excellent synergistic action of these additives and super leveling effect. In situ FTIR spectroscopic analysis combined with cyclic voltammetry measurements illustrate that the GVT adsorbs on Cu surface and thus affects the electro-reduction of cupric ions, which reveals the very complicated synergistic actions of these additives, i.e., the adsorption ability of GVT can be slightly enhanced by Cl−, while it has been greatly enhanced in the presence of PEG which nevertheless decreases slightly the inhibition effect of PEG on electro-reduction of cupric ions; the SPS plays an antagonistic effect with GVT due to their competitive adsorption. Based on the characterization of GVT as a novel leveler, we developed a GVT-based formula of THs metallization of Cu electronic plating, and demonstrated an excellent efficiency of a throwing power of 97.6% at 10 mA·cm−2 in a real PCB THs metallization of Cu electronic plating.
Lithium (Li) metal batteries are the subject of intense study due to their high energy densities. However, uncontrolled dendrite growth and the resulting pulverization of Li foil during the repeated ...plating/stripping process seriously diminish their cycling life. Herein, a facile approach using octaphenyl polyoxyethylene (OP‐10)‐based sol electrolyte is proposed to alleviate Li anode pulverization. This sol electrolyte possesses better ionic conductivity compared to gel and solid‐state electrolytes and also homogenizes Li ion diffusion throughout the entire electrolyte efficiently. As a result, Li/Li symmetric cells using this sol electrolyte demonstrate long‐term cycling stability for up to 1800 h, with a plating capacity of 3.0 mAh cm−2 without deteriorating the integrity of the thin Li foil. Using a conventional liquid electrolyte, electrode pulverization and battery failure can be observed after just three cycles. More importantly, a parameter of “throwing power” is introduced in a metal Li battery system to characterize the homogenizing ability of Li deposition in different electrolyte systems, which can serve as a guide to the efficient selection of electrolytes for Li metal batteries.
A liquid sol electrolyte is proposed as an alternative to a gel or solid‐state electrolyte to significantly alleviate the pulverization of Li anode without changing the production process of existing commercial batteries. Uniform and dense deposition, accompanied by robust solid electrolyte interphase films ensure the long‐term cycling stability of Li anodes even at a high plating capacity of 3 mAh cm−2.
In this article, an experimental programme is used to examine how boomerangs may be used to retouch stone tools. The programme's findings confirm ethnographic data pertaining to the employment of ...hardwood boomerangs in retouching activities and investigate their technological similarities to Palaeolithic bone retouchers. For the first time, the use-wear produced on boomerangs during retouching is defined and added to a reference collection. This information may be used in future studies to identify one of the many functions of boomerangs stored in museum collections in Australia and other parts of the world.
•The theoretical model and actual model of seed throwing trajectory were established.•The space distribution of sucking holes on the sucking plate was optimized.•The performance of seed throwing in ...hill was improved.•High speed photography was applied to shoot seed throwing trajectory.
Rice seeding in hill is beneficial to the growth of rice in the field and the increase of rice yield. However, rice seed metering device usually uses multiple rice seeds for sowing, which is difficult to form a hill. To improve the performance of rice seeding in hill, the seed throwing mechanism of the rice pneumatic seed metering device with adjustable seeding rate was study, and the trajectory of seed throwing was analyzed theoretically. The equation of seed throwing trajectory was established. The distribution of sucking holes on the sucking plate was optimized by using asynchronous seed throwing method. The distribution mechanism of seed throwing was studied, and the theoretical trajectory area of seed throwing was established. The actual trajectory area of seed throwing was established by high-speed photography. The theoretical area and actual trajectory area of seed throwing were compared by experiments. The influence factor of errors between the actual and theoretical seed trajectory areas were analyzed. The performance of seed throwing in hill was tested under different positive pressure and different rotational speeds. The optimum qualification rates of different seeding rates were 97.34%, 90.36% and 87.36% respectively. These were 10–17% higher than the original qualification rates of seed throwing. The experimental results showed that the optimized sucking holes on sucking plate could effectively improve the performance of seeding in hill of seed metering device. This study provided a theoretical basis for the seed throwing mechanism of the rice pneumatic seed metering device, and improved the qualification rate of seed throwing.
The high throwing power (TP) value is one of the most important parameters for the Cu electroplating of through-holes in flexible printed circuit (FPC). It was found that an ultra-high TP value could ...be obtained using a specific suppressor, i.e., iodonitrotetrazolium chloride (INT) in the electrolyte. The ultra-high TP value was attributed to fast-consumption of this suppressor instead of traditional convection-dependence adsorption mechanism. A consumption model was built and simulated to clarify the formation of the ∆
θ
, i.e., the difference of suppressor fractional coverage between the entrance and center of through-holes sidewalls. It revealed that the TP, proportional to the ∆
θ
, was determined by the consumption rate of a suppressor. This simulation results were well consistent with the results of electroplating using INT with different concentration. The electrochemical analysis verified the characteristics of fast consumption of INT due to the reduction reaction. The difference of residual INT between the entrance and center of the plated through-holes confirmed the occurrence of ∆
θ
. These results supported the opinion that the ultra-high TP value was obtained by fast-consumption mechanism of INT suppressor.
The aim of this study was to determine the movement factors that cause differences in throwing records in javelin throwers who had similar running velocities. The movements of 81 female javelin ...throwers who participated in competitions were recorded using two cameras, and the coordinate values were obtained using the three-dimensional motion analysis technique. The preparatory phase was defined as the period from the last rear foot contact (RFC) to the fore foot contact (FFC), whereas the throwing phase was defined as the period from the FFC to javelin release. Among them, 14 athletes with approach velocity of 4.0-4.3 m/s at FFC were divided into a high (57.59 ± 3.60 m) and a low group (35.14 ± 8.23 m) for throwing records, and the kinematic data were compared. The high group had a significantly higher release velocity, showed larger maximum external rotation of the shoulder joint, and larger right shoulder velocity than the low group. Immediately during the throwing phase, the high group had a larger horizontal rotation of the upper trunk towards the throwing direction than the low group. Furthermore, the high group was characterized by greater height and segment length than the low group. These results indicate that the high group achieves larger terminal velocities owing to the faster rotation of the larger body. Thus, the results clearly show that high-performance athletes transfer greater kinetic energy to the javelin throw with a more rational throwing motion, even if they have a similar approach velocity.
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