Stress wave effect in numerical simulation on rock breaking under high pressure water jet

The evolvement of rock damage struck by a high pressure water jet is characterized by nonlinear properties, thus making it a complicated dynamic problem. Based on a nonlinear finite element and elastic plasticity theory, a computational model was established. The dynamic load striking the rock by a high pressure water jet was simulated by the dynamic contact method. Furthermore, the propagation of a stress wave in the same rock was simulated at different impact velocities. The results show that the propagation velocity of a stress wave is proportional to the impact velocity of the high pressure water jet. The effects of a stress wave in sandstone and coal impacted by high pressure water jets of the same velocity were simulated.The effect of a stress wave in coal was stronger than in sandstone, while the region of propagation of stress wave in coal was smaller.     

Detecting a fault line under a single phase to ground of distribution network based on analysis of multi frequency bands

Addressing the problem of choosing a fault line under single phase to ground of distribution network, we presented a new criterion based on analysis of the development of fault line selection and a method using wavelet packets. The feature frequency band, or the combined feature frequency bands of each line, in which the transient capacity current was concentrated was chosen for maximum energy. Based on the principle that the transient capacity current's energy of the fault line was larger than the that of normal lines, fault line selection can be carried out adaptively by contrasting the energy of the transient capacity currents of all lines in each chosen frequency band. The simulation results and spot testing data shows the proposed method can detect the fault line in distribution networks precisely and reliably.     

Adaptive bit allocation algorithm in an orphogonal frequency division multiplexing system of cognitive radio

An orphogonal frequency division multiplexing(OFDM) based cognitive radio architecture was designed to meet the transmission requirements of a cognitive radio system. After finishing the allocation of subtransmission, and keeping BER within the limit that ensures service quality, an adaptive bit allocation method was proposed to allocate the bit and energy of subtransmission dynamically. The total power for launching needed reached its minimum (or SNR per bit reached its maximum). Compared with the fixed bit allocation method, the proposed method is simpler, decreases the system transmission power, and has better BER performance.     

Energy transmission process of combustion flame radiation in the tuyeres and raceways of blast furnaces

We developed a process model of flame beam transmission using pulverized coal powder and coke combustion in a raceway. We employed a Monte Carlo computation method equation based on charge couple devrce(CCD) target heat flow distribution for radiation heat transfer. We explored the factors impacting radiation transmission. Based on these, a three dimensional reconstruction was analyzed at varying coke particle concentrations. This model provided an effective method to produce on line monitoring of raceway working states.     

A new method for calculating the vacancy formation energy of typical structure metals

Based on the model proposed by Tiwari and Patil, we improved the calculation method for surface energy, and calculated the vacancy formation energy for typical metals such as fcc, bcc and hcp metals. The calculated results and experimental values agree with each other when an energy modification coefficient is introduced. The energy modification coefficients of fcc, bcc and hcp metals are 1.292, 1.265 and 1.357, respectively. The proposed method can calculate and predict the vacancy formation energy of metals efficiently.     

optimizing the CO2 supercritical fluid extraction process of isoflavone from Soybean by uniform design

A supercritical CO2 fluid extraction (SFE) method was developed to extract isoflavone. A uniform design was used to investigate the effect of the extraction pressure, extraction time, extraction temperature, and medicinal materials granularity on isoflavone extraction efficiency. The optimum conditions of extraction were as follows: 45 MPa extraction pressure, 50 ℃ extraction temperature, 4 h extraction time, 40 eyes medicinal materials granularity, and the extraction efficiency was (0.361±0.012)%.     

conductivity of a TiO2 cathode in the FFC process and analysis of its influencing factors

The conductivity of a TiO2 cathode in the FFC process was studied by sintering and electrolyzing experiments. Sintered TiO2 cathode and electrochemical reduction of TiO2 were measured using X ray diffraction. Results show that changing the energy band structure of TiO2 via high temperature sintering can cause electric conduction vacancy. An electric double layer can be formed in molten salt. Ionization of oxygen atoms leads to formation of TiO2 x ionic structures. The ions infiltrate to the electrode in molten salt, increasing the number of conduction ions. The electrolyzing process proceeds smoothly, based on the integrated mechanism of activating the TiO2 cathode. The activated TiO2 cathode can be obtained by forming electric conduction vacancy at high temperature sintering, the TiO2 x ionic structure by electric double layer, and ions infiltrating to the interior of the electrode.     

A control strategy for braking energy distribution and regenerative braking in a 4WD hybrid electric vehicle

Based on the braking theory of conventional vehicles and high efficient energy recovery and security braking, a control strategy for braking energy distribution and regenerative braking of a 4WD hybrid electric vehicle was proposed. Considering limiting factors, such as motor and battery efficiency, a simulation model of a regenerative braking system was built and a simulation of typical braking conditions was conducted. The simulation result shows that the highest energy recycle ratio can reach 87.5%, 47.8％, and 28.6％ when z is 0.1, 0.3, and 0.5, respectively, at 30 km/h. The control strategy for braking energy distribution and regenerative braking can satisfy demand for vehicle braking and obtain high regenerative energy.     

Logistics distribution optimization technology for chainassembly manufacturing enterprises

According to the demand on just in time(JIT)distribution of chain assembly manufacturing enterprise, cost optimization of backup storage and distribution betimes were analyzed. A backup storage optimization model was formulated and quantitative analysis of the JIT backup storage optimization technology for the process of logistics distribution was carried out. The optimized distribution technique to realize JIT distribution was studied, and the distribution model of logistics center and the distribution algorithm flow were established. Finally, the proposed models were applied in the planning and construction of a logistics center of an electric appliance set chain enterprise with satisfactory results.     

Deforming mechanisms in a non mandrel drawing process of an aluminum tube from circular to rectangular cross section

An elasto plastic finite element method (FEM) was used to study the deforming mechanisms of an aluminum tube drawn without a mandrel from a circular to a rectangular cross section. The simplified dynamics model and FE model of the non mandrel drawing process were established based on the FEM software deform 3D and simulations subsequently performed. Based on the simulation results, the influence of different semi die angles on the drawing load was summarized, and the proper values were found. As for the blank instability during the drawing process, the tangential stress distribution rule along the rectangle sides was acquired. The drawing die sizing section then was modified with a camber angle of 178° to eliminate instability. The touch boundary and touch stress distribution during drawing process also were analyzed. The aluminum tube produced by the optimized drawing die possesses eligible dimensions and smooth inner surfaces.