Abstract: An exemplary embodiment of the present disclosure provides a multiplexer/demultiplexer, comprising a plurality of unit cells arranged in a lattice, a first domain, a second domain, a third domain, and a controller. Each of the unit cells can comprise a topological-insulative material, a first piezoelectric patch, and a second piezoelectric patch. A first domain can comprise a first portion of the plurality of unit cells. A second domain can comprise a second portion of the plurality of unit cells. A third domain can comprise a third portion of the plurality of unit cells. The controller can be configured to: apply a negative capacitance to the first piezoelectric patches in the first domain; apply a negative capacitance to the second piezoelectric patches in the second domain; and alternately apply a negative capacitance to the first and second piezoelectric patches, respectively, in the third domain.

Abstract: In a method of driving a hydraulic system, a contracting force is applied to a hydraulic actuator, thereby causing hydraulic fluid from the hydraulic actuator to flow through a first hydraulic pump motor into a first accumulator, thereby causing the first hydraulic pump motor to apply rotational energy to a shaft. The rotational energy from the shaft is applied to a second hydraulic pump motor, thereby causing hydraulic fluid to be pumped from a second accumulator to a third accumulator so as to store energy in the third accumulator. Once energy is stored in the third accumulator, the second hydraulic pump motor is driven with hydraulic fluid stored in the third accumulator so as to apply rotational energy to the shaft, thereby driving the first hydraulic pump motor to pump hydraulic fluid from the first accumulator to the hydraulic actuator, thereby applying an expanding force to the hydraulic actuator.

Abstract: In a method of driving a hydraulic system, a contracting force is applied to a hydraulic actuator, thereby causing hydraulic fluid from the hydraulic actuator to flow through a first hydraulic pump motor into a first accumulator, thereby causing the first hydraulic pump motor to apply rotational energy to a shaft. The rotational energy from the shaft is applied to a second hydraulic pump motor, thereby causing hydraulic fluid to be pumped from a second accumulator to a third accumulator so as to store energy in the third accumulator. Once energy is stored in the third accumulator, the second hydraulic pump motor is driven with hydraulic fluid stored in the third accumulator so as to apply rotational energy to the shaft, thereby driving the first hydraulic pump motor to pump hydraulic fluid from the first accumulator to the hydraulic actuator, thereby applying an expanding force to the hydraulic actuator.