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An adaptive robust control scheme with integral sliding surface is proposed for the precision position control of the rotational chain shell magazine. The integral operation sliding surface is embedded into the traditional adaptive robust control, and the steady state position tracking error is reduced. Constant robust feedback gain is replaced by nonlinear robust feedback gain, and the transient performance is improved. Mathematical analysis shows that the proposed control scheme can achieve better transient performance and has smaller steady state position tracking error. Simulation results in three conditions (empty-loading, half-loading and full-loading) show that the proposed control scheme is insensitive to parameter variations and external disturbance. Compared with the traditional adaptive robust control scheme, the proposed control scheme has higher position precision and better control performance. [ABSTRACT FROM AUTHOR]

The conventional way takes a long time to determine the uniformity of absorbent powders in blend procedure, which is an obstacle to automation and continuation of production process of solid propellant. Near-infrared (NIR) analysis is proposed to solve that problem. A micro NIR spectrometer is used to collect the spectra of absorbent powders that are stirred continually, and the moving block of standard deviation (MBSD) algorithm is utilized to quantitatively analyze the difference between spectra of absorbent powders. The uniformity and endpoint are presented from the standard deviation-time curve. In addition, the accuracy of NIR analysis on the collected samples is confirmed through high performance liquid chromatography (HPLC). The results show that NIR analysis is efficient, eco-friendly and safe. It is feasible to apply NIR analysis to monitor the blend uniformity of modified double-base absorbent powders online and determinate the endpoint of blend process in real-time. [ABSTRACT FROM AUTHOR]

Based on the effect of depressurization, rapid depressurization property of dual-power drilling was investigated. The realizing condition of dual-power drilling and the principal of helical coal breaking were analyzed theoretically. Adopting the FLAC3D software, the model was established to study the rules of stress revolution around the relaxed slot. Besides, the industrial experiment was conducted. It indicates that the advanced free surface can eliminate the confining pressure and lower the resistance, increasing the drilling rate significantly. The relaxed slot boost the coal mass rheology occur, making the concentration stress move deeper, gas potential energy released, the coal strength enhanced and thus the fatality of outburst removed. Industrial experiment shows that after adopting this measure, the perturbation range enlarges forty times and the depressurization radius four times. The efficiency of gas drainage improves substantially, the fatality of outburst in control region is removed and tunneling progress raises two times. [ABSTRACT FROM AUTHOR]

Different models were built to simulate the crack propagation modes with different lateral pressure coefficient of hydraulic slotting area. The results show that if lateral pressure coefficient λ < 1, crack propagates along horizontal direction. When λ = 1, crack around the slotted borehole distributes uniformly. Except the above situations, the crack mainly locates in vertical direction. In addition, the number of cracks around the borehole increases with λ linearly. A similar law can be found with different λ by recording the evolution of kinetic energy. Besides, peak value of kinetic energy increase with λ. The acoustic emission (AE) shows different characteristics with different λ. While λ is small, AE events distribute discretely, when λ = 1, AE events distribute uniformly during the whole process, if λ > 1, number of AE events increase sharply first and then decrease. [ABSTRACT FROM AUTHOR]

Study the effects of different packing methods, including divided into four blocks horizontally and four blocks vertically inside the box, on natural alcoholization of Yuxi K326 C03S flue-cured tobacco lamina. The results showed that : compared with the control sample, the color of those turned faster, the oiliness of those was better, the aroma appeared earlier, with a small amount of gas ; the alcoholization process had stronger chemical reaction; the peak of sensory quality was 4 months in advance. In summary, the packing method in the box could accelerate the alcoholization reaction of the tobacco leaves and greatly shorten the alcoholization cycle of the tobacco leaves. [ABSTRACT FROM AUTHOR]