Smouldering combustion is an important and complex phenomenon that is central to a wide range of problems (hazards) and solutions (applications). A rich history of research in the context of fire safety has yet to be integrated with the more recent, rapidly growing body of work in engineered smouldering solutions. The variety of disciplines, materials involved, and perspectives on smouldering has resulted in a lack of unity in the expression of key concepts, terminology used, interpretation of results, and conclusions extracted. This review brings together theoretical, experimental, and modelling studies across both fire safety and applied smouldering research to produce a unified conceptual understanding of smouldering combustion. The review includes (i) a synthesis of nomenclature to generate a consistent set of terms for the underlying processes, (ii) an overview of smouldering emissions and emission treatment systems, (iii) a distillation of ignition and extinction research, including the role of heat losses and factors underpinning smouldering robustness, (iv) a review of the temporal and spatial distribution of heat and mass transfer processes as well as their solution using analytical and numerical methods, (v) a summary of smouldering chemical kinetics, and (vi) a summary of key gaps and opportunities for future research. Beyond merely review, a new conceptual model is provided that articulates similarities and critical differences between the two main smouldering systems: porous solid fuels and condensed fuels in inert porous media. A quantitative analysis of this conceptual model reveals that the evolution of a smouldering front, while a local process, is determined by a global energy balance that is cumulative in time and has to be integrated in space. As such, the fate of a smouldering reaction can be predicted before the effects of global heat exchange have affected the reaction. This approach is relevant to all forms of smouldering propagation (including fire safety), but it is particularly important when using smouldering as an engineered process that results in the positive use of the energy released by the smouldering reaction (applied smouldering). In applied smouldering, predicting the fate of a reaction ahead of time allows operators to modify the conditions of the process to maintain self-sustained smouldering propagation and thus fully harness the benefits of the reaction.

This study explored smoldering combustion for remediating polyfluoroalkyl substance (PFAS)-impacted granular activated carbon (GAC) and PFAS-contaminated soil. GAC, both fresh and PFAS-loaded, was employed as the supplemental fuel supporting smoldering in mixtures with sand (≈175 mg PFAS/kg GAC-sand), with PFAS-spiked, laboratory-constructed soil (≈4 mg PFAS/kg soil), and with a PFAS-impacted field soil (≈0.2 mg PFAS/kg soil). The fate of PFAS and fluorine was quantified with soil and emission analyses, including targeted PFAS and suspect screening as well as hydrogen fluoride and total fluorine. Results demonstrated that exceeding 35 g GAC/kg soil resulted in self-sustained smoldering with temperatures exceeding 900 °C. Post-treatment PFAS concentrations of the treated soil were near (2 experiments) or below (7 experiments) detection limits (0.0004 mg/kg). Further, 44% of the initial PFAS on GAC underwent full destruction, compared to 16% of the PFAS on soil. Less than 1% of the initial PFAS contamination on GAC or soil was emitted as PFAS in the quantifiable analytical suite. Results suggest that the rest were emitted as altered, shorter-chain PFAS and volatile fluorinated compounds, which were scrubbed effectively with GAC. Total organic fluorine analysis proved useful for PFAS-loaded GAC in sand; however, analyzing soils suffered from interference from non-PFAS. Overall, this study demonstrated that smoldering has significant potential as an effective remediation technique for PFAS-impacted soils and PFAS-laden GAC.

Importance: Motor and sensory challenges are commonly reported among autistic individuals and have been linked to challenges with daily living skills (DLS). To best inform clinical intervention, greater specificity in how sensory and motor challenges relate to DLS is needed. Objective: To evaluate the relationship between combined sensory and motor scores and DLS performance among autistic and nonautistic children and to explore associations between motor scores and performance on specific DLS items. Design: Descriptive design. Setting: University research lab. Participants: Autistic children, nonautistic children with no family history of or diagnosis related to autism, and nonautistic children with a family history of or diagnosis related to autism (ages 6–10 yr; N = 101). All participants communicated verbally. Intervention: None. Outcomes and Measures: Parent-report measures of DLS and sensory features and standardized assessments of motor performance. Results: Findings indicated a strong relationship between motor difficulties and all domains of DLS. At the item level, motor skills were associated with occupations of dressing, bathing, health management, cleaning up and organization, meal preparation and clean-up, education, and safety. Combined sensory and motor measures better predicted DLS than sensory or motor measures alone. Conclusions and Relevance: Children with motor and sensory challenges are likely to experience challenges with a diversity of occupations, which is important given the prevalence of motor and sensory challenges among autistic children and among children with other neurodevelopmental conditions. Therapeutic interventions that account for or address these motor challenges and associated sensory features are likely to further enhance DLS. What This Article Adds: A combination of motor challenges and sensory features better predict DLS than either motor or sensory challenges alone. In addition, motor challenges in children are most highly associated with DLS challenges in the domains of dressing, bathing, cleaning, education, safety, health, and meal preparation. Occupational therapists can use this information when considering how the results of sensory and motor assessment may guide clinical intervention in autistic and nonautistic children.

Groups serve a variety of crucial functions, one of which is the provision of an identity and belief system that impart self-referent information, thereby reducing self-uncertainty.Entitative groups are more attractive for highly uncertain participants seeking groups for identification and self-uncertainty reduction than less entitative groups. The purpose of the current study was to explore how self-uncertainty impacts physiological arousal and stress responses. Using a mixed-methods design (N = 123), we found that self-uncertainty increased physiological arousal (measured via skin-conductance level) and stress responses (measured via heart rate). Furthermore, we found that uncertaintyactivated physiological arousal and stress responses were decreased through identification with a high entitativity group. Our findings expand upon uncertainty identity theory by identifying physiological mechanisms that motivate uncertainty reduction.

Many Americans’ political identity is more relevant, salient, and central than their American identity. Political parties provide party members with an identity and belief system. Political identities influence identity‐based ideologies which increase affective polarization and potential anti‐social intergroup conflict between political parties. The purpose of the current research is to determine how political party identification and ideological extremity influences affective polarization for Republicans and Democrats across two studies. Participants in both studies completed a survey which measured political identification, ideological extremity, and uniquely operationalized measures of affective polarization, including support for co‐partisans, attitudes about political rivals, emotions towards political rivals, action tendencies towards political rivals, and perceived threat from political rivals. Study 1 (N = 530) used responses to the survey from a convenience sample crowdsourced by Amazon Mechanical Turk (AMT) in 2018. Study 1 showed that higher political party identification is associated with significantly higher affective polarization for members of both parties and that ideological extremity partially mediates this effect. Study 2 (N = 260) used a 2020 AMT sample to replicate Study 1’s results. Findings extend our understanding of identity‐based ideological extremity and suggest that affective polarization could be driven by political party identification and partisans’ ideological extremity.