One benefit attributable to blending of alternative jet fuels into conventional petroderived kerosenes is reduced sooting tendency relative to the conventional unblended kerosenes. This benefit is largely due to the lower aromatics content of the alternative fuels/blends, and it is desirable with respect to sooting tendency limits embedded in aviation turbine fuel specifications (e.g., ASTM D1655 and D7566). However, the relatively high smoke points of many alternative jet fuels are not directly measurable by the prevailing ASTM D1322 smoke point (SP) method and its international variants. This frustrates characterization of these alternative fuels and prediction of their blending properties. The present work addresses an extrapolative "virtual" smoke point (VSP) technique for determination of smoke points compatible with the ASTM D1322 standard. Importantly, this compatibility removes the significant ambiguity historically associated with measurements of non-standard smoke points, herein categorically designated SP*. The VSP approach invokes the linear-by-mole blending functional basis of the Threshold Sooting Index (TSI), which has been empirically demonstrated in the literature for both defined molecular species and complex hydrocarbon fluids. If the average molecular weights (MWs) of the blending component fuels are known, then the VSPs of low-sooting tendency fuels can be forecast using D1322 SP measurements. This is demonstrated here for iso-octane and ndodecane as illustrative pure-component test fuels, as well as the full boiling range POSF 7720, a camelina sativa-derived hydrotreated jet fuel (HRJ). In part, the approach is facilitated by the ability to easily determine the average molecular weight of a fuel using a method recently developed by this laboratory. Nomenclature a = device-dependent parameter for calculation of TSI (molmm/g) b = device-dependent parameter for calculation of TSI (-) m i-j = slope of linear-by-mole TSI blending rule for fuels i and j (-) MW = (mixture-average) molecular weight (g/mol) r = repeatability limit of the ASTM D1322 smoke point method (mm) SP = ASTM D1322 smoke point (mm) SP* = non-standard, device-dependent smoke point used in general definition of TSI (mm) TSI = threshold sooting index (-) VSP = "virtual" smoke point (mm) X i = (molar) blend fraction of fuel i (-) γ i-j = slope of linear-by-mole MW/SP blending rule for fuels i and j (g/mol/mm) δ = fuel i intercept of linear-by-mole MW/SP blending rule for fuels i and j (g/mol/mm) 1
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Ferrimagnetic domain walls are attracting more and more attentions due to their interesting physics and potential applications in future spintronic devices, particularly attributes to the non-zero net magnetization and ultrafast dynamic properties. Exploring effective methods for driving domain walls with low energy consumption and high efficiency does provide important information for experimental design and device development. In this work, we study theoretically and numerically the dynamics of ferrimagnetic domain wall driven by the sinusoidal microwave magnetic field using the collective coordinate theory and Landau-Lifshitz-Gilbert simulations of atomistic spin model. It is revealed that the microwave field can drive the propagation of the domain wall along nanowires when the frequency falls into appropriate regions, which allows one to modulate the domain wall dynamics through tuning field frequency. Specifically, the domain wall velocity is proportional to the field frequency and the net angular momentum below the critical frequency, while it quickly decreases to zero above the critical frequency. The physical mechanisms of the results are discussed in detail, and the influences of the biaxial anisotropy and other parameters on the velocity of domain wall are explored. Thus, it is suggested that the domain wall dynamics can be effectively regulated by adjusting the basic magnetic structure and magnetic anisotropic, in addition to the external microwave field frequency. This work uncovers interesint dynamics of ferrimagnetic domain wall driven by sinusoidal microwave magnetic field, which is helpful for domain wall-based spintronic device design.
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