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Objectives: Ear reconstruction is a challenging surgery for the complicated conditions in patients with microtia. The tissue expansion techniques were necessary and relatively safe for patients with insufficient soft tissue. However, complications such as necrosis of expanded flap and exposure of tissue expander limited the popularization of this method. This study described the use of modified Brent method to handle the exposure of the postauricular tissue expander. Methods: From January 2013 to December 2019, 27 ear reconstruction patients with trauma or necrosis on an expanded skin flap and subsequent exposure of tissue expander were treated with modified Brent method, which consisted of 3 stages: removal of the expander, tension-free closure of wound, and framework fabrication; elevation of reconstructed ear; lobule rotation; and minor modification. Results: Fifty-six percent of exposures occurred in the lower pole of the tissue expander. Exposure usually occurred 54.5 days after implantation. The majority of reconstructed ears had a satisfactory appearance and showed relatively stable outcomes. Only one case of cartilage exposure required revision surgery and was repaired by the temporoparietal fascia. Conclusion: With reasonable distribution of expanded flap, prolonged interval, and sutures under tension-free conditions, complications like the occurrence of trauma or necrosis-induced exposure of tissue expander can be repaired efficiently by a staging modified Brent method. [ABSTRACT FROM AUTHOR]

A binary mixture of ionic liquid 1-ethyl-3-methylimidazolium thiocyanate ([C2mim][SCN]) and methanol was prepared along with the whole composition range. Thermodynamic properties such as densities, dynamic viscosities, and electrical conductivities of binary system were measured from 293.15 to 323.15 K at 101.3 KPa. The electrical conductivities dependences of IL mole fraction were graphically described by the Casteel–Amis four-parameter equation. The excess molar volumes (VE) and dynamic viscosity deviations (Δη) of the binary mixture were calculated and satisfactorily fitted by the Redlich–Kister polynomial equation to reveal the interactions that exist among the components. For a deep understanding of the intermolecular interactions of the binary mixture, the infrared spectrum analysis was used to provide the observable changes related to the structural features, and the stable structures, energies of the complexes involving cation or anion of [C2mim][SCN] and methanol molecule were calculated by density functional theory calculations at B3LYP/6-311++G** level of calculation to evaluate the interaction situations of the IL and methanol. [ABSTRACT FROM AUTHOR]

Swirling flows are widely used in industrial burners and gas turbine combustors for flame stabilization. Several prior studies have shown that these flames exhibit complex dynamics under near blowoff conditions, associated with local flamelet extinction and alteration in the vortex breakdown flow structure. These extinction events are apparently due to the local strain rate irregularly oscillating above and below the extinction strain rate values near the attachment point. In this work, global temporally resolved and detailed spatial measurements were obtained of hydrogen/methane flames. Supporting calculations of extinction strain rates were also performed using detailed kinetics. It is shown that flames become unsteady (or local extinctions happen) at a nearly constant extinction strain rate for different hydrogen/methane mixtures. Based upon analysis of these results, it is suggested that classic Damkohler number correlations of blowoff are, in fact, correlations for the onset of local extinction events, not blowoff itself Corresponding Mie scattering imaging of near blowoff flames also was used to characterize the spatio-temporal dynamics of holes along the flame that are associated with local extinction. [DOI: 10.1115/1.4000601] Keywords: swirling, hydrogen, lean blowout

This paper describes measurements of the dependence of lean blowout limits upon fuel composition for [H.sub.2]/CO/C[H.sub.4] mixtures. Blowout limits were obtained at fixed approach flow velocity, reactant temperature, and combustor pressure at several conditions. Consistent with prior studies, these results indicate that the percentage of [H.sub.2] in the fuel dominates the mixture blowout characteristics. That is, flames can be stabilized at lower equivalence ratios, adiabatic flame temperatures, and laminar flame speeds with increasing [H.sub.2] percentage. In addition, the blowoff phenomenology qualitatively changes with hydrogen levels in the fuel, being very different for mixtures with [H.sub.2] levels above and below about 50%. It is shown that standard well stirred reactor based correlations, based upon a Damkohler number with a diffusivity ratio correction, can capture the effects of fuel composition variability on blowoff limits. [DOI: 10.1115/1.2718566] Keywords: syngas, lean blowout, hydrogen