Motivated by the demographic effects, we propose and analyze a novel opinion dynamics model with density-dependent interactions and a nonlinear communication function reminiscent of the celebrated Hegselmann–Krause (H–K) model. The model also incorporates heterogeneity through intrinsic opinion tendencies, leading to richer dynamics. In the homogeneous case, where all agents share the same intrinsic tendency, the relative dissimilarities between opinions converge to zero and a single cluster forms. In contrast, under heterogeneous tendencies, we prove that multiple clusters emerge together with velocity alignment within each cluster, provided suitable structural conditions on the system parameters. These theoretical findings are further supported by numerical simulations, which offer qualitative insights beyond the analytical results.
Ammonia (NH3) co-firing offers a pragmatic pathway for decarbonizing coal-fired power plants; however, the impact of coal rank on the flame structure and emission characteristics in swirl-stabilized combustion environments remains under-investigated. This study evaluated the co-firing characteristics of bituminous and subbituminous coals in an 80 kWth pilot-scale down-fired furnace under a constant NH3 injection velocity, which enabled a stable combustion atmosphere even at high co-firing ratios of up to 40%. Internal temperature distributions were corrected using a suction-pyrometer to ensure data integrity and eliminate radiation-induced measurement errors. The results revealed that combustion behaviors and optimal emission control strategies diverged significantly depending on the coal rank. Bituminous coal maintained a stable high-temperature zone (1150-1200 degrees C) near the burner. Under a 0.9 burner air ratio, it significantly reduced NO levels to 172.7 ppm at a 40% co-firing ratio, which was facilitated by its moderate volatile release and high char-surface reactivity. By contrast, the high-temperature zone for sub-bituminous coal exhibited a downstream shift owing to rapid devolatilization and intensified oxygen competition between NH3 and coal volatiles. For sub-bituminous coal, the optimal burner air ratio (1.0) limited NO emissions to 201.4 ppm at a 40% co-firing ratio. This study demonstrated that stable combustion can be sustained at high substitution rates by controlling the NH3 injection velocity. By providing mechanistic insights and quantitative guidelines for reaction zone control based on coal rank, the findings serve as a fundamental technical basis for developing and designing large-scale NH3 co-firing systems.
Mindfulness-based cognitive therapy (MBCT) integrates cognitive therapy and mindfulness meditation to help individuals disengage from maladaptive thoughts and reactive behavioral patterns. By cultivating nonjudgmental present-moment awareness and decentering from thoughts and emotions, MBCT enhances the capacity to respond more skillfully, thereby reducing impulsivity and promoting self-control. This study pilot-tested the effectiveness of MBCT for internet gaming disorder (MBCT-G) among college-aged students at risk for problematic gaming, focusing on reducing symptoms of internet gaming disorder and secondarily on psychological benefits. A pilot experimental study was conducted in South Korea with 46 college-aged students at high risk of internet gaming disorder. The intervention group (n = 24) participated in eight group sessions of MBCT-G and a control group (n = 22) received no intervention. Internet gaming disorder, impulsivity, depressive symptoms, perceived stress, anxiety, and self-control were assessed before and after the intervention and at 4 weeks postintervention. Linear mixed-model analyses indicated participants in the intervention group had greater reductions in internet gaming disorder symptoms, perceived stress, and state anxiety and enhanced improvement in self-control relative to the control group; these changes persisted at 4-week follow-up except for state anxiety. Findings suggested MBCT-G is a promising intervention for college-aged students whose gaming is problematic and puts them at risk for gaming disorder. Further research is needed with a larger sample, a comparison group receiving an alternative intervention and a longer follow-up period. This study was not prospectively registered; however, it was retrospectively registered with ISRCTN Registry (# ISRCTN17598517).
