Nowadays falls are a serious problem for elderly people with the coming of aged society in the world. According to statistics,hip fracture accounts for the most of the deaths and costs of all the fall-induced injury. This paper presented an airbag system of hip protection, which included air source, sensors, microcontroller, gas circuit and airbags. A six-axial inertial sensor module that integrated an embedded three-axis MEMS accelerometer and three-axis MEMS gyroscope was used to collect human motion data, and a one-axis obliquity sensor was used to collect human angle data. The microcontroller was employed to recognize the activities of daily living (ADL) and falls based on fall detection algorithm and the collected data from sensors. The gas circuit was triggered once the event that the fall would be inevitable was confirmed by the microcontroller, then the compressed gas would fill into airbags through the gas circuit rapidly. Therefore, a buffer would appear between the human body and the ground before the body impacting the ground, which would reduce the impact of the human body. Compressed CO2 was selected as the air source after we tested several kinds of gas. A 16g CO2 pressurized cylinder could provide enough pressure and volume to inflate quickly the airbags. In order to improve the reliability of the gas circuit, a needle valve was optimized from the several designed structures by the experimental optimization methods. Finally, the airbag system was tested in various designed trials. The results indicated that the system gained the satisfaction for the design requirements and would be potential to apply to the protection of hip joint in the fall high-risk people in the future.
Abstract-This paper presents an SPH (smoothed particle hydrodynamics) model for numerical simulation of multiphase drop dynamics including liquid drop formation and deformation, coalescence and separation, liquid drop impacting, spreading and splashing. SPH is a Lagrangian, meshfree particle method. It has special advantages in modeling multiphase drop dynamics. Surface tension effects are modeled using a particle-particle interaction force, which avoids the calculation of surface and interface curvature. Solid boundaries are modeled using a coupled dynamic boundary treatment algorithm, which ensures the accuracy and flexibility of the SPH method. Numerical investigations of a liquid drop oscillation and a single liquid drop impacting onto a liquid film are conducted. The inherent physics of multiphase drop dynamics are well described.
A new conception, called the Most Direct Impact Area (MDIA) of typhoons, is put forward in this paper. After the computational method is explained in detail, the databank of 1955 typhoons of China Meteorological Administration (CMA) have been calculated on the Linux operational platform with a Fortran compiler in a computer. The results via calculating the geographic distribution of the MDIA of typhoons show that the characteristic of typhoon activity in a year can be easily identified in quantity. A most interesting feature has been found that typhoon activity is abnormally active over the ocean to the south of Japan in three typical El Niño years.
According to the structural characteristics of the electrical one-line diagram at substation, Its proposed that designing the database which stores electrical properties and graphics properties of the equipment in the paper. And an intelligent graphical modeling and automatic implement of main electrical connections are achieved based on the database. By means of the graph database integrated platform, a topology analyzing method based on bus for main electrical connections is presented, which is capable of not only computer graphics processing easily, but also describing accurately and reliably the topological structure of the main electrical connections. Finally the node admittance matrix is generated and the calculation of short circuit current is completed automatically.
Solar storms and power engineering HVDC, make the earth there geomagnetic induced current and direct current. If the DC current into the neutral grounding transformer, the transformer will be caused bias magnetic phenomena, changing its excitation characteristics, interfere with the normal operation of power systems and equipment. This paper considers the impact on the excitation characteristics of hysteresis effects, establishing excitation characteristics calculation model, proposes an improved graphics corresponding method to calculate and analyze the open circuit excitation characteristics of single-phase transformer in three columns under DC bias, the experimental results prove the validity of the proposed method.
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