Thermal and chemical kinetic characterization of multiphase and multicomponent substances by laser heating

Thermochemical Characterization of Bio- and Petro-diesel Fuels Using a Novel Laser-Heating Technique

“…The system was originally designed to limit effects of a nonuniform temperature distribution in the middle of the sphere. The uniformity in temperature of heating a sample placed within the center of the sphere (for a volume with dimensions of about 10 mm diameter by 5 mm height) is of the order of 1 K. 28 Within the sample, heat transfer is by conduction. The lumped-capacitance approximation 30 is invoked, in which the sample is spatially uniform in temperature at any instant of time during the transient process, as long as the Biot number < 0.1, which is satisfied to be for this investigation.…”

“…The mode of thermal analysis for these experiments is based on heating the reactor to a steady-state temperature (referred to as the 'heating-rate' approach). 28 Experiments were initially carried out for the 'baseline thermogram' (i.e., sample and reactor temperature measurements with respect to time including the pan substrate and no sample), and then repeated with the sample ('sample thermogram'). From these thermograms, we also define the 'sample-baseline temperature difference' profiles (i.e., subtracting the sample thermogram and that of the baseline for either the sample or reactor temperatures), and the 'sample' or 'reactor' derivative profiles (i.e., variation of the sample or reactor temperature-time derivative with time or sample/reactor temperature for either the sample or baseline thermograms).…”

“…When using relatively low heating rates, as with some commercial thermal calorimetry systems, volatiles vaporize before reaching the operating steady-state temperature. 28 For relatively high heating rates or too small sample mass, then the sample is consumed before completion of the thermal cycle, both situations resulting in the loss of important information in the thermograms. The mass estimate for these experiments was (2.55 ± 0.1) mg for the B100 fuel, (5.00 ± 0.1) mg for the SRM 2772 biodiesel fuel, and (4.30 ± 0.1) mg for the SRM 2771 diesel fuel.…”

“…The mode of thermal analysis used for these experiments involves heating the reactor at two different laser fluences (referred to as the 'heating-rate' approach). 28 For this approach, the sample (i.e., in this case, the baseline without sample) and reactor temperatures are recorded for two runs at two different laser fluences, as illustrated in Fig. 3.…”

Surface patterning of multilayer graphene by ultraviolet laser irradiation in biomolecule sensing devices

“…To fabricate a graphene-based sensing device, the surface graphene can be ablated at the same low threshold fluence via a laser patterning route by using a multiple pass in-motion technique. This study used a long-pulse UV nanosecond laser (1 > ns), because even laser ablation at a low energy fluence may induce thermal effects (plasma heating) [33,34]. Because the laser energy in this study was absorbed by the graphene surface ( Fig.…”