This study examines how destination brand equity was distributed across the PyeongChang 2018 Olympic period. A matched panel of 502 U.S.-based target-market respondents evaluated South Korea approximately three months before and three months after the Games. The post-event measure intentionally captured evaluations attributed by respondents to hosting the Games and is therefore interpreted as an early event-attributed response rather than a causal Olympic effect. Separate-wave latent profile analyses, supported by focused four-versus-five-state validation, retained five ordered destination-brand-equity states. Average destination brand equity was higher at the post-event observation (mean difference = .340), but this positive net difference coexisted with substantial between-person heterogeneity. A fixed-criterion regression-to-the-mean benchmark reproduced the small residual net direction but not the observed volume of gross bidirectional redistribution, while reliable-change analysis indicated that most respondents did not exceed a conservative change threshold. After baseline adjustment, media consumption and hosting appraisal were positively associated with the post-event score, whereas their interaction was not significant. The findings show why aggregate brand tracking and individual-level diagnostics should be interpreted jointly and distinguish early event-attributed responses from durable mega-event legacy.
The electropulsing anisotropy of pre-twinned AZ31 Mg alloy was investigated via quasi-in-situ electron backscatter diffraction analysis to decouple the thermal and athermal effects of electropulsing treatment. A pre-compression along the rolling direction (RD) introduced extensive {10−12} extension twins, yielding a twinned area fraction of 75.4%. Three consecutive electropulses were applied along the RD or the transverse direction (TD), with the durations tailored to maintain comparable peak temperatures. The TD specimens exhibited higher heating efficiency owing to the predominant a-axis current path preserved in both matrix and twinned regions despite twinning-induced lattice rotation. A finite difference simulation based on the c-axis orientation distribution predicted an electrical resistivity ratio in excellent agreement with the experimental value. Quasi-in-situ tracing revealed that strain-induced boundary migration governed the early stage of microstructural evolution, while nucleation and growth gradually became activated during subsequent cycles; thermally activated twin boundary migration was suppressed under the subsecond thermal exposure. Notably, the RD specimens underwent faster grain growth and twin boundary annihilation than the TD counterparts, contrary to predictions based on grain morphology and texture. This anomalous behavior was ascribed to current crowding in the twinned regions, where the lower resistivity along the c-axis locally amplified the athermal effect, as evidenced by preferential static recovery under a short-duration electropulse. The RD specimens recovered more ductility (up to 71%) than the TD counterparts (19%). This ductility recovery was governed primarily by the deformation behavior associated with the tensile direction and further enhanced by the accelerated microstructural evolution in the RD specimens, which delayed the onset of plastic instability.
HfS2 is a layered semiconductor for electronic and optoelectronic applications, but humidity-assisted native oxidation limits its ambient stability. Raman spectroscopy probes HfS2 degradation but is time-consuming and condition-sensitive. Here, we revisit a previously reported HfS2 aging dataset to develop a Raman-calibrated image-based framework for rapid, non-destructive screening of CVD-grown HfS2 films on c-plane sapphire. Photographs collected under a documented configuration yielded predefined color, histogram, texture, and spatial descriptors. A simple, interpretable regression using only CIE Lab b* with physical-range clipping achieved a within-library, query-excluded leave-one-day-out RMSE of 6.78 days for 21 queries from three optically evolving conditions: native HfS2 at 35% and 70% RH and PMMA-capped HfS2 at 70% RH. The b*-based model performed comparably to kNN (7.70 days) and significantly better than a no-information pool-mean baseline (9.84 days, p = 0.0030), indicating that more complex estimators provided no clear benefit in the present dataset. Under leave-one-pair-out evaluation of 20 image-Raman pairs, the combined image-derived estimate showed a trend-level relationship with measured normalized A1g intensity (R2 = 0.600), while ΔE gave the best individual result (R2 = 0.701). The framework identified its limits: severe degradation of native HfS2 at 70% RH was underestimated, whereas Al2O3-encapsulated HfS2 showed insufficient optical evolution for reliable chronological estimation. Accordingly, this material- and configuration-specific method is a proof-of-concept screening framework, not a universal dating model or a substitute for Raman spectroscopy. Within this scope, controlled photography provides interpretable pre-screening of broad aging states and prioritizes samples for Raman or chemical analysis.
This study experimentally investigated the wall friction characteristics of single-phase water flow in vertical annular channels of a natural circulation loop under mixed convection conditions at elevated temperatures. Experiments were conducted in annular test sections with gaps of 2.9, 5, and 7 mm at 30 bar for a Reynolds number (Re) range of 663–5003. Under these low-velocity mixed convection conditions, the wall friction factor increased with increasing annular gap size and inlet fluid temperature, and decreased with increasing flow velocity. Over the investigated Richardson number (Ri) range of 0.13–4.86, the wall friction factor increased up to approximately nine times the corresponding forced convection value. As Ri decreased and inertial effects became dominant, the friction factor approached the forced convection prediction. This behavior is consistent with buoyancy-induced modification of the velocity profile and the resulting changes in near-wall shear, coupled with temperature-dependent fluid-property variations. A machine-learning-based analysis identified Ri, the viscous dissipation parameter (N), and the Prandtl number (Pr) as the most influential dimensionless parameters governing wall friction enhancement. Based on these results, a new correlation was developed to predict wall friction factors. The applicability ranges of the proposed correlation are 0.13 ≤ Ri ≤ 4.86, 7.91 × 10⁻9 ≤ N ≤ 3.17 × 10⁻⁸, and 1.15 ≤ Pr ≤ 2.72. The experimental dataset provides a valuable benchmark for the development and validation of wall friction models under mixed convection conditions, and the proposed correlation enables improved prediction of wall friction factors within the present experimental range.
