Printing technology promises a viable solution for the low-cost, rapid, flexible, and mass fabrication of biosensors. Among the vast number of printing techniques, screen printing and inkjet printing have been widely adopted for the fabrication of biosensors. Screen printing provides ease of operation and rapid processing; however, it is bound by the effects of viscous inks, high material waste, and the requirement for masks, to name a few. Inkjet printing, on the other hand, is well suited for mass fabrication that takes advantage of computer-aided design software for pattern modifications. Furthermore, being drop-on-demand, it prevents precious material waste and offers high-resolution patterning. To exploit the features of inkjet printing technology, scientists have been keen to use it for the development of biosensors since 1988. A vast number of fully and partially inkjet-printed biosensors have been developed ever since. This study presents a short introduction on the printing technology used for biosensor fabrication in general, and a brief review of the recent reports related to virus, enzymatic, and non-enzymatic biosensor fabrication, via inkjet printing technology in particular.

Biofuels are environmental friendly renewable fuels, that can be directly used in a diesel engine. However, a few shortcomings like a higher density, viscosity, a lower calorific value and increase in NOx emissions, has caused researchers to look for fuel additives to improve the physiochemical properties of these fuels and to enhance their performance and reduce harmful emissions. It is for this reason that modern research is focused on blending oxygenated additives such as alcohols and ethers with different generations of biodiesel. Since most studies have covered the effect of alcohol on biodiesel, there are few studies which have investigated the effect of oxygenated additives such as alcohols and ethers, especially related to second-generation biodiesel. Moreover, the details of their composition and molecular structure are still lacking. Hence, this study focuses on the performance and emission characteristics of biodiesel with the inclusion of oxygenated additives (alcohols and ethers) of non-edible-oil-based second-generation blends. The reviewed results showed that Neem biodiesel with methanol or diethyl ether reduced brake-specific fuel consumption by 10%, increased brake thermal efficiency by 25% and reduced CO and HC emissions due to a higher oxygen content. Diethyl ether reduced NOx emissions as well by producing a cooling effect, i.e., a reduced in-cylinder temperature. The addition of heptane, butanol and di ethyl ether to Jatropha biodiesel showed an improved brake thermal efficiency and an increment in brake-specific fuel consumption (5–20%), with reduced HC and CO₂ (3–12%) emissions. Calophyllum inophyllum biodiesel also showed impressive results in terms of improving efficiency and reducing emissions with addition of butanol, pentanol, decanol and hexanol. Other factors that influenced emissions are the cetane number, viscosity, density and the latent heat of evaporation of tested biodiesel blends. This review would help the research community and the relevant industries to consider an efficient biodiesel blend for future study or its implementation as an alternate fuel in diesel engines.

During the thermal sintering of metal nanoparticles (NPs) the process temperature plays the most important role in the outcome of the sintering results and the selection of a suitable substrate. Here, temperature calculation during pulsed laser sintering of silver (Ag) nanoparticles (NPs) inkjet-printed on glass substrates is presented. During the pulsed laser sintering of Ag NPs, a minimum line resistivity less than twice the bulk silver resistivity was obtained within around 52 s under a laser power of 276 mW. The temperature field during the pulsed laser sintering of Ag NPs was estimated via a three-dimensional numerical model in which a temperature-dependent thermal conductivity of Ag NPs was adopted. An algorithm for treating the thermal conductivity of the heated Ag NPs in a region by a previous laser shot was devised for the improvement of the temperature field estimation. A maximum temperature of approximately 204 °C over the Ag NPs line was obtained with a 276 mW laser power and a scanning speed of 135 μm/s.

Owing to its unique properties, silver (Ag) in the form of nanoparticle (NP) ink promises to play a vital role in the development of printed and flexible electronics. Once printed, metal NP inks require a thermal treatment process called sintering to render them conductive. Among the various methods, electrical sintering is a highly selective and rapid sintering method. Here, we studied the electrical sintering of inkjet-printed Ag NP lines via a stepwise current increment sintering (SCIS) technique. In the SCIS technique, the supplied electric current was gradually increased in multiple steps from low electric currents to higher electric currents to avoid thermal damage to the printed Ag NP ink lines. In less than 0.15 s, a line resistivity as low as 6.8 μΩcm was obtained which was comparable with furnace sintered line resistivity of 6.13 μΩcm obtained at 250 °C in 600 s. Furthermore, a numerical model was developed for the SCIS process temperature estimation. The results enabled us to elaborate on the relationship between the Ag NP line resistivity and the process temperature under various electric currents. Under the applied SCIS technique, a stable sintering process was carried out avoiding the conductive ink line and substrate damage.