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The present study investigated how visual characteristics of a fire influence extinguisher use. Safety guidance indicates that occupants should consider situational aspects when deciding whether to use an extinguisher, such as fire characteristics. The visual fire cues of intensity, growth rate, and smoke thickness were systematically manipulated to examine the impact on judgments to intervene with an extinguisher. Participants (N = 135) viewed simulated fire scenes as part of an experiment and judged whether they could safely attempt to use an extinguisher. The results indicated that the participants were significantly less likely to attempt extinguisher use with greater fire intensity and thicker smoke. In contrast, variations in fire growth rate did not significantly affect participant decisions. These findings indicate that perceived fire intensity and smoke density are strong factors in extinguisher use decisions, while growth rate may not meaningfully influence occupant behavior. Understanding these perceptual factors can inform fire safety education and improve guidance on when extinguisher use is appropriate, potentially enhancing residential fire response outcomes. 

The ability of a fire extinguisher to suppress fires varies by the rated performance of the unit. Safety guidance in the United States indicates that the occupant should consider the performance rating of the extinguisher when deciding to use it with a fire. The present study investigated whether individuals are aware of the connection between the suppression performance of fire extinguishers and the intensity of fires the unit can extinguish. Across five experiments, participants were presented with fire extinguishers that varied in suppression performance (smaller, medium, and larger) and judged whether the extinguisher could extinguish a developing room fire that increased in intensity. The fire intensity at which they stopped attempting to use the extinguisher (threshold) was calculated. No significant differences in threshold were observed by suppression performance condition when suppression information about the single extinguisher at hand was presented. This included when information was provided about the amount of agent, the distance and duration of discharge, and with the water equivalent the extinguisher was rated. However, when trained on the differences in suppression performance between extinguishers and provided with corresponding containers of water, thresholds did vary by performance rating. We discuss how providing information about variations in suppression performance may be necessary to highlight differences in extinguisher ratings. 

Recent research has used virtual environments (VEs), as presented via virtual reality (VR) headsets, to study human behavior in hypothetical fire scenarios. One goal of using VEs in fire scenarios is to elicit patterns of behavior which more closely align to how individuals would react to real fire emergency situations. The present study investigated whether elicited behaviors and perceived risk varied during fire scenarios presented as VEs via two viewing conditions. These included a VR condition, where the VE was rendered as 360-degree videos presented in a VR headset, and a screen condition, where VEs were rendered as fixed-view videos via a computer monitor screen. We predicted that the selection of actions during the scenario would vary between conditions, that participants would rate fires as more dangerous if they developed more quickly and when smoke was rendered as thicker, and that participants would report greater levels of immersion in the VR condition. A total of 159 participants completed a decision-making task where they viewed videos of an incipient fire in a residential building and judged what action to take. Initial action responses to the fire scenarios varied between both viewing and smoke conditions, with those assigned to the thicker smoke and screen conditions being more likely to take protective action. Risk ratings also varied by smoke condition, with evidence of higher perceived risk for thicker smoke. Several factors of self-reported immersion (namely ‘interest’, ‘emotional attachment’, ‘focus of attention’, and ‘flow’) were associated with risk ratings, with perceived presence associated with initial actions. The present study provides evidence that enhancing immersion and perceived risk in a VE contributes to a different pattern of behaviors during simulated fire decision-making tasks. While our investigation only addressed the ideas of presence in an environment, future research should investigate the relative contribution of interactivity and consequences within the environment to further identify how behaviors during simulated fire scenarios are affected by each of these factors. 

Metal alloys frequently contain distributions of second-phase particles that deleteriously affect the material behavior by acting as sites for void nucleation. These distributions are often extremely complex and processing can induce high levels of anisotropy. The particle length-scale precludes high-fidelity microstructure modeling in macroscale simulations, so computational homogenization methods are often employed. These, however, involve simplifying assumptions to make the problem tractable and many rely on periodic microstructures. Here we propose a methodology to bridge the gap between realistic microstructures composed of anisotropic, spatially varying second-phase void morphologies and idealized periodic microstructures with roughly equivalent mechanical responses. We create a high-throughput, parametric study to investigate 96 unique bridging methods. We apply our proposed solution to a rolled AZ31B magnesium alloy, for which we have a rich dataset of microstructure morphology and mechanical behavior. Our methodology converts aµ-CT scan of the realistic microstructure to idealized periodic unit cell microstructures that are specific to the loading orientation. We recreate the unit cells for each parameter set in a commercial finite element software, subject them to macroscopic uniaxial loading conditions, and compare our results to the datasets for the various loading orientations. We find that certain combinations of our parameters capture the overall stress–strain response, including anisotropy effects, with some degree of success. The effect of different parameter options are explored in detail and we find that excluding certain particle populations from the analysis can give improved results. 

Abstract Protein activity, abundance, and stability can be regulated by post-translational modification including ubiquitination. Ubiquitination is conserved among eukaryotes and plays a central role in modulating cellular function; yet, we lack comprehensive catalogs of proteins that are modified by ubiquitin in plants. In this study, we describe an antibody-based approach to enrich ubiquitinated peptides coupled with isobaric labeling to enable quantification of up to 18-multiplexed samples. This approach identified 17,940 ubiquitinated lysine sites arising from 6,453 proteins from Arabidopsis (Arabidopsis thaliana) primary roots, seedlings, and rosette leaves. Gene ontology analysis indicated that ubiquitinated proteins are associated with numerous biological processes including hormone signaling, plant defense, protein homeostasis, and metabolism. We determined ubiquitinated lysine residues that directly regulate the stability of three transcription factors, CRYPTOCHROME-INTERACTING BASIC-HELIX-LOOP-HELIX 1 (CIB1), CIB1 LIKE PROTEIN 2 (CIL2), and SENSITIVE TO PROTON RHIZOTOXICITY1 (STOP1) using in vivo degradation assays. Furthermore, codon mutation of CIB1 to create a K166R conversion to prevent ubiquitination, via CRISPR/Cas9-derived adenosine base editing, led to an early flowering phenotype and increased expression of FLOWERING LOCUS T (FT). These comprehensive site-level ubiquitinome profiles provide a wealth of data for future functional studies related to modulation of biological processes mediated by this post-translational modification in plants. 

The acoustic and aerodynamic fields of blunt porous plates are examined experimentally in an effort to mitigate trailing-edge bluntness noise. The plates are characterized by a single dimensionless porosity parameter identified in previous works that controls the influence of porosity on the sound field. Hot-wire anemometry interrogates the velocity field to connect turbulence details of specific regions to flow noise directivity and beamforming source maps. Porous plates are demonstrated to reduce the bluntness-induced noise by up to 17 dB and progressively suppress broadband low-frequency noise as the value of the porosity parameter increases. However, an increase in this parameter also increases the high-frequency noise created by the pores themselves. The same highly perforated plate characterized by a large value of the porosity parameter reduces the bluntness-induced vortex shedding that is present in the wake of the impermeable plate. Lastly, pore shape and positional alignment are shown to have a complex effect on the acoustic field. Among the porosity designs considered, plates with circular pores are most effective for low-frequency noise reductions but generate high-frequency noise. No meaningful difference is found between the acoustic spectra from plates of the same open-area fraction with pores aligned along or staggered about the flow direction. 

IntroductionThe goal of the present research was to develop a video collection of simulated fires to investigate how people perceive growing building fires. In fire safety science, a critical factor to occupant responses to building fires is the pre-movement period, determined by how long it takes an individual to initiate taking protective action with an incipient fire. Key to studying the psychological processes that contribute to the duration of the pre-movement period is presenting human subjects with building fires. One approach used in previous research is to present videos of building fires to individuals via scenarios. The numerical simulations used to model fire dynamics can be used to render videos for these scenarios. However, such simulations have predominantly been used in fire protection engineering to design buildings and are relatively inaccessible to social scientists. MethodThe present study documents a collection of videos, based on numerical simulations, which can be used by researchers to study human behavior in fire. These videos display developing fires in different types of rooms, growing at different rates, different smoke thickness, among other characteristics. As part of a validation study, participants were presented with subsets of the video clips and were asked to rate the perceived risk posed by the simulated fire. Results and discussionWe observed that ratings varied by the intensity and growth rate of the fires, smoke opacity, type of room, and where the viewpoint was located from the fire. These effects aligned with those observed in previous fire science research, providing evidence that the videos could elicit perceived risk using fire simulations. The present research indicates that future studies can utilize the video library of fire simulations to study human perceptions of developing building fires as situational factors are systematically manipulated.