In this work, a new method for the fabrication of organic solar cells containing functional light-trapping nanostructures on flexible substrates is presented. Polyimide is spin-coated on silicon support substrates, enabling standard micro- and nanotechnology fabrication techniques, such as photolithography and electron-beam lithography, besides the steps required for the bulk-heterojunction organic solar cell fabrication. After the production steps, the solar cells on polyimide are peeled off the silicon support substrates, resulting in flexible devices containing nanostructures for light absorption enhancement. Since the solar cells avoid using brittle electrodes, the performance of the flexible devices is not affected by the peeling process. We have investigated three different nanostructured grating designs and conclude that gratings with a 500 nm pitch distance have the highest light-trapping efficiency for the selected active layer material (P3HT:PCBM), resulting in an enhancement of about 34% on the solar cell efficiency. The presented method can be applied to a large variety of flexible nanostructured devices in future applications.

A high-speed and high-temperature calorimetric solid-state thermal mass flow sensor (TMFS) design was proposed and its sensitivity to temperature and airflow speed were numerically assessed. The sensor operates at 573.15 Kelvin (300 °C), measuring speeds up to 265 m/s, and is customized to be a transducer for an aircraft Air Data System (ADS). The aim was to enhance the system reliability against ice accretion on pitot tubes’ pressure intakes, which causes the system to be inoperative and the aircraft to lose protections that ensure its safe operation. In this paper, the authors assess how the distance between heater and thermal sensors affects the overall TMFS sensitivity and how it can benefit from the inclusion of a thermal barrier between these elements. The results show that, by increasing the distance between the heater and temperature sensors from 0.1 to 0.6 mm, the sensitivity to temperature variation is improved by up to 80%, and that to airspeed variation is improved by up to 100%. In addition, adding a thermal barrier made of Parylene-N improves it even further, by nearly 6 times, for both temperature and air speed variations.

Food waste in perishable products calls for the development of cost-efficient and real-time freshness and shelf life assessment tools. The current study evaluated a newly developed cadaverine biosensor for its ability to assess the sensory freshness stage and microbial quality of modified atmosphere packed (MAP) pork cutlets under a realistic supply chain scenario. The experiment compared the cadaverine levels measured by the biosensor to liquid chromatography - tandem mass spectrometry (LC-MS/MS) cadaverine concentrations, and associated these to the shelf life estimation and freshness states determined by sensory and microbial evaluations during an 18-day storage period (5 °C). Results underlined the potential of cadaverine as a freshness biomarker as well as the applicability of the biosensor as a shelf life prediction tool. This is supported by the correlations obtained between sensory odour freshness evaluation and total viable counts with biosensor cadaverine levels for which the r obtained were 0.97 (<0.001) and 0.95 (<0.001), respectively.