Low-dimensional HfS2 as SO2 adsorbent and gas sensor: Effect of water and sulfur vacancies

First-principles based on density functional theory (DFT) calculations were performed to investigate the interaction of two-dimensional (2D) HfS2 with SO2, a harmful gas with implications for climate change. In particular,...

Cattle Detection Using Oblique UAV Images

The evolution in imaging technologies and artificial intelligence algorithms, coupled with improvements in UAV technology, has enabled the use of unmanned aircraft in a wide range of applications. The feasibility of this kind of approach for cattle monitoring has been demonstrated by several studies, but practical use is still challenging due to the particular characteristics of this application, such as the need to track mobile targets and the extensive areas that need to be covered in most cases. The objective of this study was to investigate the feasibility of using a tilted angle to increase the area covered by each image. Deep Convolutional Neural Networks (Xception architecture) were used to generate the models for the experiments, which covered aspects like ideal input dimensions, effect of the distance between animals and sensor, effect of classification error on the overall detection process, and impact of physical obstacles on the accuracy of the model. Experimental results indicate that oblique images can be successfully used under certain conditions, but some practical limitations need to be addressed in order to make this approach appealing.

Influence of Pt paste and the firing temperature of screen-printed electrodes on the NO detection by pulsed polarization

Symmetrical Pt|YSZ|Pt sensors were produced by screen printing with frit-containing and fritless Pt pastes and fired at 950, 1100, and 1300 ∘C. Subsequently, the sensors were operated by pulsed polarization, and the NO sensitivity was investigated. The sensitivity of the sensors with fritless pastes was found to be significantly higher. The influence of the firing temperature was low in contrast to the influence of the paste. The low NO sensitivity of the frit-containing electrodes was attributed to a blocking effect that probably occurs at the triple-phase boundaries. Therefore, the oxygen transport through the sensor is inhibited, which, however, seems to be necessary for the sensor effect.

Cu/CuO@ZnO Hollow Nanofiber Gas Sensor: Effect of Hollow Nanofiber Structure and P–N Junction on Operating Temperature and Sensitivity

For the fast and easy detection of carbon monoxide (CO) gas, it was necessary to develop a CO gas sensor to operate in low temperatures. Herein, a novel Cu/CuO-decorated ZnO hollow nanofiber was prepared with the electrospinning, calcination, and photodeposition methods. In the presence of 100 ppm CO gas, the Cu/CuO-photodeposited ZnO hollow nanofiber (Cu/CuO@ZnO HNF) showed twice higher sensitivity than that of pure ZnO nanofiber at a relatively low working temperature of 300 °C. The hollow structure and p–n junction between Cu/CuO and ZnO would be considered to contribute to the enhancement of sensitivity to CO gas at 300 °C due to the improved specific surface area and efficient electron transfer.