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Tracing leaks of airborne radio-active, poisonous or flammable materials is a potentially dangerous activity that could be undertaken by robotic systems. This paper describes a practical investigation of the possibility of developing simple, low cost, autonomous robots to perform this task. It is envisaged that these robots would be used in large numbers. This would improve reliability through redundancy and provide large area coverage from a wide distribution of robots. Failure of a single unit would not jeopardise the overall sensing operation. Sensing and control techniques developed to perform leak location in a simplified laboratory environment are described and experimental results are presented.

Laser reduction of graphene oxide has attracted significant interest in recent years, because it offers a highly flexible, rapid and chemical-free graphene fabrication route that can directly write on almost any solid substrate with down to submicron feature size. Laser-reduced graphene (LRG) has been explored for various important applications such as supercapacitors, sensors, field effect transistors, holograms, solar cells, flat lenses, bolometers, thermal sound sources, cancer treatment, water purification, lithiumion batteries, and electrothermal heaters. This contribution reviews most recent research progress on the aspects of fabrication, properties and applications of LRG. Particular attention is paid to the mechanism of LRG formation, which is still debatable. The three main theories, including the photochemical process, the photothermal process, and a combination of both processes are discussed. Strategies for tuning the properties and performance of LRG, such as the laser parameters, chemical doping, structure modulation, and environment control have been highlighted. LRGs with better performance including smaller feature size, higher conductivity, and more flexible morphology design in both two-dimensional and three-dimensional format will offer tremendous opportunities for advancement in electronics, photonic, and optoelectronic applications.

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Laser reduction of graphene oxide is a promising technology for manufacturing advanced devices such as supercapacitors, sensors and transistors, owing to its distinctive advantages in selective and localized GO reduction, direct micro-nanoscale patterning, and no requirement for chemicals. However, the fundamental mechanism underlying the laser induced reduction is still not well understood. In this paper, we demonstrate that by adjusting the power and scanning speed of a 780 nm femtosecond laser, not only can one distinguish, but also effectively tune, two coexisting sub-processes during the laser reduction, namely the direct conversion from sp 3 to sp 2

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