Tonghun, "Ignition behavior and surrogate modeling of JP-8 and of camelina and tallow hydrotreated renewable jet fuels at low temperatures" (2012
b s t r a c tThe autoignition characteristics of the conventional jet fuel, JP-8, and the alternative jet fuels, camelina and tallow hydrotreated renewable jet (HRJ) fuels, are investigated using a rapid compression machine and the direct test chamber charge preparation approach. Ignition delay measurements are made at low compressed temperatures (625 K 6 T c 6 730 K), compressed pressures of p c = 5, 10, and 20 bar, and equivalence ratios of / = 0.25, 0.5 and 1.0 in air. The HRJ fuels ignite more readily than JP-8 for all tested conditions, consistent with derived cetane number data in the literature. The camelina and tallow HRJ fuels exhibit similar autoignition characteristics, but the two fuels can be distinguished under stoichiometric conditions. Kinetic modeling is conducted with a 2-component surrogate (10% n-dodecane/90% 2-methylundecane) and a single component surrogate (2-methylnonane) to evaluate the potential to predict ignition behavior of the HRJ fuels. Modeling results indicate that the surrogate fuels can only provide useful predictions at a limited set of conditions (p c = 5 bar and / = 1.0), and that the agreement of the model and experimental data improves with decreasing compressed pressure. Under most conditions, the 2-component surrogate provides better prediction of ignition behavior, but the single component surrogate is superior at low pressures near the negative temperature coefficient region.
Strongly
bound interlayer excitons (XIs) in atomically
thin transition metal dichalcogenide (TMDC) heterostructures such
as MoS2/WSe2 show promising optoelectronic properties
for spin-valleytronics and excitonic devices. The ability to probe
and control XIs is critical for the development of such
applications. This Letter introduces a versatile chemical method for
selectively tailoring interlayer excitons in TMDC heterostructures.
We show that two organic layers form uniform layers on a WSe2/MoS2 heterostructure and that the XI photoluminescence
may be either preserved or quenched. The interlayer emission can also
be modulated differently by the formation of the organic layer on
either side of the TMDC/TMDC heterostructure. We find that the resulting
interlayer emission is dominated by selective photoinduced charge
transfer over dark-state p-doping effects. These results shed critical
insights on interlayer excitons at the TMDC/TMDC heterointerfaces
and provide a versatile approach for selectively tailoring them for
optoelectronic applications.
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