This paper illustrates the characterization of a fabric resistance temperature (RTD) detector made from electrospun nylon-6 functionalized with multiwalled carbon nanotubes (MWCNTs) and polypyrrole (PPy) for use in supracutaneous applications like smart clothing, prosthetic sockets, and other medical devices where a temperature detecting fabric is better suited than a rigid detector. The nanocomposite material acts like a RTD, because the conductivity increases linearly with temperature. The empirically determined temperature coefficient of resistance (TCR) is reported for this material, and is -0.204 ± 0.008%/C. Development of a simple and scalable process for constructing the detector utilized electrospinning nylon-6 as a membrane style substrate, vacuum filtration of MWCNTs onto the nylon scaffold, and vapor phase polymerization of pyrrole to PPy onto the MWCNT functionalized nylon nanofibers. The optimal loading of MWCNTs is 6.6 wt%. The conductivity of the device follows a percolative behavior and TCR values indicate this is a viable option for temperature detection. Resistance decreases with increasing temperature, which indicates this is a negative TCR material.

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There have been increasing demands and interests in stretchable sensors with the development of flexible or stretchable conductive materials. These sensors can be used for detecting large strain, 3D deformation, and a free-form shape. In this work, a stretchable conductive sensor has been developed using single-walled carbon nanotubes (SWCNTs) and monofunctional acrylate monomers (cyclic trimethylolpropane formal acrylate and acrylate ester). The suggested sensors have been fabricated using a screw-driven microdispensing direct-write (DW) technology. To demonstrate the capabilities of the DW system, effects of dispensing parameters such as the feed rate and material flow rate on created line widths were investigated. Finally, a stretchable conductive sensor was fabricated using proper dispensing parameters, and an experiment for stretchability and resistance change was accomplished. The result showed that the sensor had a large strain range up to 90% with a linear resistance change and gauge factor ∼2.7. Based on the results, it is expected that the suggested DW stretchable sensor can be used in many application areas such as wearable electronics, tactile sensors, 3D structural electronics, etc.

A domino free 4-path time-interleaved second order sigma-delta modulator is proposed. This timeinterleaved scheme uses only one integrator channel along with incomplete integrator output terms to completely eliminate the quantizer domino which is a key limit for the practical circuit implementation of conventional multi-path time-interleaved sigma-delta modulators. In addition, the single integrator channel leads to considerable hardware reduction as well as path mismatch insensitivity, since only one global feedback path is required. As a result, the switched capacitor implementation of the 4-path time-interleaved second order sigma-delta modulator is enabled with the conventional 2-phase clocking scheme by using only 5 op-amps.

Abstract-A time-interleaved sigma-delta modulator using the output prediction scheme is proposed. This approach uses only one integrator channel along with incomplete integrator output terms to eliminate the quantizer domino which is a key limit for practical circuit implementation of conventional time-interleaved sigma-delta modulators. In addition, channel mismatch effects due to mismatch within multiple integrator feedback paths can be reduced by optimizing the feedback path. An equivalent two-channel time-interleaved version of the conventional second-order sigma-delta modulator is realized to verify the proposed method.Index Terms-Channel mismatch, incomplete integrator outputs, output prediction, quantizer domino, sigma-delta modulators, time-interleaved.