Study of Enhanced Fine Coal De-sulphurization and De-ashing by Ultrasonic Flotation

The feasibility of using ultrasound to enhance the performance of de-sulphurization and de-ashing during slime flotation was investigated. The Setararn C80 calorimeter, the contact angle gauge DCAT21 and an electrophoresis apparatus were used to study the surface nature of coal, pyrite and refuse before and after ultrasonic conditioning. The yield, ash and sulfur contents of equally sized coal slimes were also measured before and after ultrasonic conditioning. The results show that ultrasonic conditioning can drive the separation of pyrite and refuse from coal. After ultrasonic conditioning the hydrophobicity of coal and hydrophilicity of pyrite and refuse increase. The perfect index of flotation, the perfect index of de-sulphurization and the percentage of de-sulphurization increase by 22.51%, 25.36% and 2.49%, respectively. This study shows that ultrasonic conditioning can enhance the performance of de-sulphurization and de-ashing of coal flotation methods.

Screening of Surface Medication Agents and Modification Mechanism of Fly Ash

The fly ash from Jixi power plant was treated with various surface modifiers. The surface properties of the modified fly ash,including active index wetting angle,were measured in this paper. The modified fly ash was filled into rubber to improve the rubber properties. The results of rubber tests indicate that the type of the surface modifiers has a great influence on the rubber reinforcing properties. The fly ash modified by titanate coupling agents exhibits the best performance in respect to rubber reinforcing properties. The test results show that the fly ash can take place of some decomposition material so that the dosage of decomposition in rubber can be reduced,resulting in the low producing cost of rubber and the low pollution of fly ash.

Study on the Relationship between.the Moisture Content of Brown Rice and Milling Characteristics

An experiment about rice milling was made to study on the relationship between the different moisture content of brown rice and the energy consumption, the broken rice rate, the crack rate and the head rice yield. It could be concluded that the head rice yield increased at first falls and then along with the raise of moisture content and it could reach the maximum 70.78% when moisture content was 15.5%; the energy consumption of rice milling decreased along with the increase of moisture contents; the broken rice rate fell at first and then increased along with the raise of moisture contents and it could reach the minimum 4.28% when the moisture content was 15.5%.

Control Strategy of a Two-Lap Connection Converter

Two-lap sequential control converters are usually adopted to supply and improve the power factor of input side. The line harmonic damage generated by a sequential control thyristor converter can be serious. To solve this prob-lem and seek an optimum control strategy,we derived the changeable regular of the line-input-current,the fundamen-tal-frequency-current,the harmonic-current-content and the harmonic total distortion ratio of the converter at different firing angles. We obtained relevant data from experiments with a sequential control system of a DC 2.2kW/220V motor. With the example of the operating condition of a DC mine elevator,the harmonic current is two times approximately in sequential control compared to synchronous control when the firing angle of the two converters differs in 30°. At dif-ferent operating states of a two-lap connection converter,the ideal strategy is an exchange between sequential control and synchronous control,by which we can achieve the complementary goal of improving the power factor and har-monic effect. All analytical conclusions are supported by simulation and experimental results.

Lift fin stabilizers based on data fusion with wavelet denoising technology

Fin stabilizers with fin-lift feedback control can shield the mapping error of calculation between the fin angle and fin lift force,which is in the fin stabilizer with fin-angle feedback control.In practice,there are some technical difficulties in lift fin stabilizers,such as lift force detection and lift force sensor installation,so it cannot achieve the good antirolling performance.Therefore,a fin stabilizer system with fin-lift/fin-angle integrated control is brought forward.Data fusion based on wavelet denoising technology is employed in the system,which combines lift with fin angle local information from two sensors with different frequency ranges in order to eliminate redundant and contradictory information,and using complementary information to obtain the relative integrity of the lift force signal.The system model is established in this paper,and the fusion signal and the antirolling performance of this model are simulated respectively.The result shows that the control system can meet the antirolling need in different sea situations.

Convergence of self-tuning Riccati equation with correlated noises

For the linear discrete time-invariant stochastic system with correlated noises, and with unknown model parameters and noise statistics, substituting the online consistent estimators of the model parameters and noise statistics into the optimal time-varying Riccati equation, a self-tuning Riccati equation is presented. By the dynamic variance error system analysis （DVESA） method, it is rigorously proved that the self-tuning Riccati equation converges to the optimal time-varying Riccati equation. Based on this, by the dynamic error system analysis （DESA） method, it is proved that the corresponding self-tuning Kalman filter converges to the optimal time-varying Kalman filter in a realization, so that it has asymptotic optimality. As an application to adaptive signal processing, a self-tuning Kalman signal filter with the self-tuning Riccati equation is presented. A simulation example shows the effectiveness.