Epidermal pH is an indication of the skin’s physiological condition. For example, pH of wound can be correlated to angiogenesis, protease activity, bacterial infection, etc. Chronic non-healing wounds are known to have an elevated alkaline environment, while healing process occurs more readily in an acidic environment. Thus, dermal patches capable of continuous monitoring of pH can be used as point-of-care systems for monitoring skin disorder and the wound healing process. Here, we present pH-responsive hydrogel fibers that can be used for long-term monitoring of epidermal wound condition. We load pH-responsive dyes into mesoporous microparticles and incorporate them into hydrogel fibers developed through microfluidic spinning. The fabricated pH-responsive microfibers are flexible and can create conformal contact with skin. The response of pH-sensitive fibers with different compositions and thicknesses are characterized. The suggested technique is scalable and can be used to fabricate hydrogel based wound dressing with a wide range of sizes. Images of the pH-sensing fibers during real-time pH measurement can be captured with a smart phone camera for convenient readout on-site. Through image processing, a quantitative pH map of the hydrogel fibers and the underlying tissue can be extracted. The developed skin dressing can act as a point-of-care device for monitoring the wound healing process.

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With the development of wide-area measurement technology, it is possible to synchronously obtain the traveling waves from different measuring points in a complex power grid. Considering fault-generated traveling wave transmits along the shortest path in the power grid and timestamps of wave fronts can be acquired by phase-mode transformation and wavelets, this paper proposes an optimal deployment scheme of traveling wave recorders (TWR) in the power grid based on the extended double-end fault-location method. Then the fault-location methodology is presented. It is critical to guarantee that the double-end method is applied to the power grid and recognizes the specialized measuring combinations preciously and quickly, and the fault can be located consequently wherever it occurs. At last, fault-location accuracy is improved by the correction approach. All simulations are carried out in PSCAD/EMTDC, and the proposed procedure is applied to the IEEE 30& 57-bus test system to exam its validation. The results show that it can accurately locate a fault with 13 TWRs in IEEE 30-bus test system and 16 TWRs in IEEE 57-bus test system, and absolute error is less than 20 m.