The dynamic response of gas sensors based on poly(3-hexylthiophene) (P3HT) nanofibers(NFs) to gaseous acetone was assessed using a setup based on flow-injection analysis, aimed atemulating actual breath exhalation. The setup was validated by using a commercially available sensor.The P3HT NFs sensors tested in dynamic flow conditions showed satisfactory reproducibility down toabout 3.5 ppm acetone concentration, a linear response over a clinically relevant concentration range(3.5-35 ppm), excellent baseline recovery and reversibility upon repeated exposures to the analyte,short pulse rise and fall times (less than 1 s and about 2 s, respectively) and low power consumption(few nW), with no relevant response to water. Comparable responses' decay times under eithernitrogen or dry air suggest that the mechanisms at work is mainly attributable to specific analytesemiconductingpolymer interactions. These results open the way to the use of P3HT NFs-basedsensing elements for the realization of portable, real-time electronic noses for on-the-fly exhaledbreath analysis.

Poly(3-hexylthiophene) (P3HT) nanofibers fabricated by self-assemby have been used as active sensing layers in chemiresistive gas sensors for acetone, ammonia and water. Their response has been compared to that of analogous devices in which P3HT was present as a plain, nonnanostructured layer. The results of this comparison show that nanofiber-based sensors have faster signal decay times and complete baseline recovery even after being exposed to saturated vapors of the analytes. Moreover, the current response of nanofiber-based devices increases by one order of magnitude or more upon exposure to the analyte, while for plain layers this increase is about 50% at maximum. Finally, on the basis of the\ud collected data, a correlation between the analyte polarizability and the 90% baseline recovery times seems to exist, likely due to the occurrence of just physical adsorption (and not also of vapor penetration) of the analyte onto the polymer surface

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This paper presents a physical channel emulator solution for applications such as Bit Error Rate Testing of Error Correcting Codes. The solution relies on an analog White Gaussian Noise Generator coupled additively with an analog data signal to emulate the communication channel. This is interfaced to a computer through a USB connection, allowing the use of programs in different environments, such as Matlab and Labview. This solution can allow different types of channels to be emulated and with different noise sources. A software-based method to measure Signal to Noise Ratio and to characterize the channel is also presented. The system has been validated using a Matlab interface implementing multiple error correcting codes and showed good agreement with the theoretical model.