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This paper introduces a design for an ultralowpower electromyogram (EMG) signal amplifier with low noise operation. The design consists of two stages, the first stage is highly efficient but supply-sensitive single ended amplifier and the second stage is differential, to improve the supply rejection ratio and common mode rejection ratio. Each stage is configured with cascode MOSFET transistors to increase the gain value. The proposed design is simulated by 130 nm CMOS, and its results are reported. The design achieves 60.62 dB mid-band gain with bandwidth of 1.72kHz. Using a supply voltage of 1.1 V, the amplifier consumes 1.03 μA of current. Input referred noise is 3.006 μVrms. The common mode and power supply rejection ratios are above 49.05 dB and 55.72 dB respectively.

This paper introduces a design for an ultralowpower electromyogram (EMG) signal amplifier with low noise operation. The design consists of two stages, the first stage is highly efficient but supply-sensitive single ended amplifier and the second stage is differential, to improve the supply rejection ratio and common mode rejection ratio. Each stage is configured with cascode MOSFET transistors to increase the gain value. The proposed design is simulated by 130 nm CMOS, and its results are reported. The design achieves 60.62 dB mid-band gain with bandwidth of 1.72kHz. Using a supply voltage of 1.1 V, the amplifier consumes 1.03 μA of current. Input referred noise is 3.006 μVrms. The common mode and power supply rejection ratios are above 49.05 dB and 55.72 dB respectively.

This paper introduces a design for an ultralowpower electromyogram (EMG) signal amplifier with low noise operation. The design consists of two stages, the first stage is highly efficient but supply-sensitive single ended amplifier and the second stage is differential, to improve the supply rejection ratio and common mode rejection ratio. Each stage is configured with cascode MOSFET transistors to increase the gain value. The proposed design is simulated by 130 nm CMOS, and its results are reported. The design achieves 60.62 dB mid-band gain with bandwidth of 1.72kHz. Using a supply voltage of 1.1 V, the amplifier consumes 1.03 μA of current. Input referred noise is 3.006 μVrms. The common mode and power supply rejection ratios are above 49.05 dB and 55.72 dB respectively.

The objective of this paper is to evaluate the performance of pillars located on level #3 at Nohyun Limestone Mine that uses the room-and-pillar method. The mine is located at South of Cheongju city, North Chungcheong Province, South Korea. A series of two-dimensional elasto-plastic finite-difference models has been constructed using FLAC2D software. Factor of safety (FOS) is then calculated using fish-code (“solve FOS”), an internal command of FLAC built on a shear strength reduction technique. The results are presented and discussed in terms of stress state, deformation and factor of safety with respect to mining sequence, mining depth and mineshaft width. The results reveal that, the stability of pillars deteriorates when level #3 is entirely mined out after extracting level #2 (i.e. FOS =1.33 to 1.55). In addition, the safety of pillars is sharply dropped (i.e. FOS =1.16 to 1.33) when mining depth extends to 15m; and similarly, width of mineshaft increases by 2m. Also, a comparison of calculation of safety factor, FOS, employing numerical modelling (i.e. FOS =1.16 to 1.86) and analytical methods (i.e. FOS = 7.35 to 36.36) has revealed that numerical modelling is more conservative from a design point of view. The study also indicates that, the overall mine stability is influenced by the discordance in the pillar arrangement between adjacent levels. Therefore, it is recommended that, the pillar design should be dictated by the inclination of the orebody.

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