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Contemporary Photonic Integrated Circuit (PIC) packages within the communications network infrastructure have reached a thermal limit. Integrated packages involving microfluidic channels are an appealing development to improve the thermal design of future PIC packages, to significantly improve the removal of heat fluxes in order to sustain the expected enhanced data traffic growth. The Thermally Integrated Smart Photonics Systems (TIPS) project aims to develop and demonstrate a thermally enabled integrated platform that is scalable, to meet the predicted data traffic demands. Full system integration requires an integrated pumping solution, therefore a primary heat exchanger that can deliver the required thermal performance with a low pressure drop (ΔP) is needed. A channel containing a single array of cylindrical posts offers a low pressure drop, similar to a large hydraulic diameter minichannel. Local destabilization of the flow would provide heat transfer enhancement. In particular, non-Newtonian fluids have been shown to exhibit significant mixing in such configurations. Micro Particle-Image Velocimetry (μPIV) measurements were taken for Newtonian and viscoelastic fluids within this channel. Instabilities associated with the viscoelastic fluid were recorded immediately upstream of the post array. This flow exhibited almost a four-fold increase in mixing at comparable flow rates to the Newtonian fluid tested. This suggests that the Nusselt number enhancement associated with such flows could increase the heat transfer rates quite significantly in microchannels containing obstructions.

This paper focuses on the evolution of Physics textbooks used in Ireland from 1860 to 2022, in addition to the Irish influence on early Physics textbooks in the latter part of the 19th century. Both Physics and Physics education are continually evolving and so textbooks change in response to that and to the changing priorities of educators. Physics is both experimental and theoretical and the presentation of it has always been multimodal. Physics textbooks tend to include diagrams, demonstrations, experiments, the use of mathematics and derivations, historical references to people, and applications of Physics, among other features. Our research looks at these various characteristics to discern what has changed and what has not, over the course of time. Twenty-eight textbooks were examined in the course of this study. A Physics concept (refraction) and a Physics instrument (electroscope) were chosen for special attention, so that the findings would be firmly rooted in how Physics has been represented in textbooks rather than general textbook publishing trends. A specific analysis of four textbooks by the same two authors across three syllabi is also presented. Our findings show that a great deal has changed in the realm of Physics textbooks, and given that this is the case, it is remarkable how many things changed very little in 162 years.

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