The methane capturing and its utilization is of great importance for the safety in Polish coal mines. The present study deals with methods which are used to capture and utilize it in hard coal mines. It is of great im...The methane capturing and its utilization is of great importance for the safety in Polish coal mines. The present study deals with methods which are used to capture and utilize it in hard coal mines. It is of great importance to know that at present, ethane recovered in operating mines is obtained only through drainage systems whose implementation is enforced by health and safety regulations. Because of the fact that the amount of methane released in hard coal mines is expected to rise in years to come, as the methane content of coal seams increases with depth, heavy emphasis should be placed on methane recovery and the practical applications of the captured gas. If mine gas was officially recognised as a primary source for producing ＂environmentally friendly electricity＂, would open the perspectives of increasing methane utilization. In addition, the mining industry would gain an incentive to intensify methane recovery. It would be possible to carry out additional work focused on methane drainage from excavations which are not operated. Also, the costs of methane drainage could be included in the costs of energy production, which would undoubtedly have a positive effect on the profitability of mining companies.展开更多
The present paper discusses a design method for the head position in a Hard Disk Drive （HDD） control system. In the HDD control system, the sampling interval of the head position is constrained because of the hardwa...The present paper discusses a design method for the head position in a Hard Disk Drive （HDD） control system. In the HDD control system, the sampling interval of the head position is constrained because of the hardware specifications, but the hold interval of the control input is not constrained. In the present study, a multirate control system is designed, in which the sampling and the hold intervals are not equal. A multirate control law, which stabilizes a closed-loop system, is extended using newly introduced parameters such that the sample response of the plant output is maintained. Furthermore, intersample ripples in the steady state are eliminated using the new design parameters, which can be selected independently of the sample response. As a result, the intersample response can be improved independently of the sample response. The proposed method is applied to a benchmark problem of an HDD system, and its effectiveness is demonstrated.展开更多
文摘The methane capturing and its utilization is of great importance for the safety in Polish coal mines. The present study deals with methods which are used to capture and utilize it in hard coal mines. It is of great importance to know that at present, ethane recovered in operating mines is obtained only through drainage systems whose implementation is enforced by health and safety regulations. Because of the fact that the amount of methane released in hard coal mines is expected to rise in years to come, as the methane content of coal seams increases with depth, heavy emphasis should be placed on methane recovery and the practical applications of the captured gas. If mine gas was officially recognised as a primary source for producing ＂environmentally friendly electricity＂, would open the perspectives of increasing methane utilization. In addition, the mining industry would gain an incentive to intensify methane recovery. It would be possible to carry out additional work focused on methane drainage from excavations which are not operated. Also, the costs of methane drainage could be included in the costs of energy production, which would undoubtedly have a positive effect on the profitability of mining companies.
文摘The present paper discusses a design method for the head position in a Hard Disk Drive （HDD） control system. In the HDD control system, the sampling interval of the head position is constrained because of the hardware specifications, but the hold interval of the control input is not constrained. In the present study, a multirate control system is designed, in which the sampling and the hold intervals are not equal. A multirate control law, which stabilizes a closed-loop system, is extended using newly introduced parameters such that the sample response of the plant output is maintained. Furthermore, intersample ripples in the steady state are eliminated using the new design parameters, which can be selected independently of the sample response. As a result, the intersample response can be improved independently of the sample response. The proposed method is applied to a benchmark problem of an HDD system, and its effectiveness is demonstrated.
