Stretchable and Flexible High-Strain Sensors Made Using Carbon Nanotubes and Graphite Films on Natural Rubber

Conventional metallic strain sensors are flexible, but they can sustain maximum strains of only ~5%, so there is a need for sensors that can bear high strains for multifunctional applications. In this study, we report stretchable and flexible high-strain sensors that consist of entangled and randomly distributed multiwall carbon nanotubes or graphite flakes on a natural rubber substrate. Carbon nanotubes/graphite flakes were sandwiched in natural rubber to produce these high-strain sensors. Using field emission scanning electron microscopy, the morphology of the films for both the carbon nanotube and graphite sensors were assessed under different strain conditions (0% and 400% strain). As the strain was increased, the films fractured, resulting in an increase in the electrical resistance of the sensor; this change was reversible. Strains of up to 246% (graphite sensor) and 620% (carbon nanotube sensor) were measured; these values are respectively ~50 and ~120 times greater than those of conventional metallic strain sensors

Investigation of NiO film by sparking method under a magnetic field and NiO/ZnO heterojunction

Nickel oxide (NiO) film receives attention from the field of optoelectronics due to its wide band gap and high transparency. By using a sparking method, the deposition of the NiO film is facile and unique. However, the NiO film made by the sparking method indicates a porous surface with an agglomeration of its particles. In order to reduce the porousness of the NiO film, the assistance of a permanent magnet in the sparking apparatus is presented. Here, we report the investigation of the NiO film and the p-NiO/n-ZnO heterojunction deposited by the sparking method under a magnetic field. Our results demonstrate that the porosity of the NiO film was reduced by increasing the magnitude of a magnetic field from 0 mT to 375 mT. Furthermore, the crystallinity and the electrical properties of the NiO film are improved by the influent of a magnetic field. For heterojunction, the best device shows the rectification ratio of 95 and the ideality factor of 4.92. This work provides an alternative method for the deposition of the NiO film with promising applications in optoelectronic devices

Physicochemical properties and fatty acid profile of oil extracted from black soldier fly larvae (Hermetia illucens)

Background and Aim: Hermetia illucens, a black soldier fly, is widely recognized for sustainable recycling of organic waste. Black soldier fly larvae (BSFLs) can consume various types of biowastes and convert them into nutrient-rich biomass, including proteins, lipids, chitin, and minerals. This study investigated the best extraction method by comparing the fatty acid profiles, percentage yield, and antioxidant properties of BSFL oil extracted using different extraction methods. Materials and Methods: The physicochemical properties, fatty acid profile, and free radical scavenging ability of BSFL oil were analyzed using six extraction methods. Results: Ultrasonic extraction with hexane resulted in the highest yields compared with different extraction methods. Lauric acid (28%–37%) was the most abundant fatty acid in all extracts, followed by palmitic acid, myristic acid, oleic acid, and linoleic acid. Compared with other methods, aqueous extraction showed the highest lauric acid composition and free radical scavenging activities. In addition, high-temperature aqueous extraction resulted in higher oil yield and free radical scavenging activities than low-temperature extraction. Conclusion: High-temperature aqueous extraction is the best extraction method because it is rich in lauric acid, has antioxidant ability, and can be further developed to produce novel sustainable biomaterials for humans and animals

DC Magnetron Sputtering Deposition of Titanium Oxide Nanoparticles: Influence of Temperature, Pressure and Deposition Time on the Deposited Layer Morphology, the Wetting and Optical Surface Properties

Titanium dioxide nanoparticles were prepared on glass substrates by reactive DC magnetron sputtering. As highlighted by the atomic force microscopy characterization, we were able to control the nanoparticles' surface coverage and diameter by varying the deposition time and the total pressure, respectively. The titanium dioxide energy band gap, determined by using ultraviolet-visible, spectroscopy, depends on the total pressure but is quite independent of the deposition temperature. On the contrary, it is blue shifted when the pressure increases. Finally, the contact angles slightly decrease after ultraviolet illumination irrespective of the different deposition parameters, indicating an improvement of the hydrophilic properties of the adsorbed layer. After 21 h in dark, the contact angles are nearly identical to the ones before exposure to UV light: the samples do not keep their hydrophilic behaviour