It’s not the batteries! Smoke alarm presence and functionality 5-7 years post installation of sealed lithium battery alarms

Smoke alarms with lithium batteries have been marketed as long life or “10 Year Alarms.” Previous work has drawn into question the actual term of functionality for lithium battery alarms. This paper reports on observed smoke alarm presence and functionality in a sample of 158 homes which had participated in a fire department smoke alarm installation program 5-7 years prior to the observations. A total of 394 alarms were originally installed in the 158 homes that completed the revisit. At the time of the revisit, 214 of those alarms were working (54%), 26 were non-working (7%), and 154 were missing (39%). Of the 158 homes that completed the revisit, n=62 (39%) had all their originally installed project alarms up at working at the revisit. Respondents who reported owning their homes and who reported living in their home for 6 or more years were significantly more likely than renters and those living in their homes for 5 or fewer years were more likely to maintain all of their project alarms. Smoke alarm installation programs should consider revisiting homes within 5-7 years post installation to inspect and replace any missing or non-functioning alarms. We recommend programs conducting community risk reduction programs track and plan installations and revisits to improve smoke alarm coverage.

Design of Smoke Alarm Disperser Based on Single-chip Microcomputer

With the rapid development of society and economy, various laboratories have become more complete in number and equipment, but subsequent laboratory accidents frequently occur. Therefore, it is imperative to construct a laboratory safety management system to ensure the safety of laboratory personnel and complete equipment. This article intends to design a smoke alarm, which mainly includes measuring the sensitivity of the smoke sensor to the concentration of smoke in the air, and the linear change of the sensor converting the corresponding analog signal into a digital signal. By designing the fan speed to be controlled by the change of smoke density, the speed of the motor is adjusted. And the alarm module can sound an alarm when the smoke concentration is certain, and at the same time, it can automatically cancel the alarm when the smoke concentration decreases. Finally, a simulation experiment is designed to simulate the effect of the sound alarm of the smoke alarm disperser on the dispersal of smoke under different working environments.

The Drosophila gene smoke alarm regulates nociceptor-epidermis interactions and thermal nociception behavior

The detection and processing of noxious sensory input depends on the proper growth and function of nociceptor sensory neurons in the peripheral nervous system. In Drosophila melanogaster, the class IV (cIV) multidendritic dendritic arborization (md-da) neurons detect noxious stimuli through their highly branched dendrites that innervate the epidermis of the larval body wall. Here, we describe requirements of a previously uncharacterized gene named smoke alarm (smal), a discoidin domain receptor, in cIV md-da dendrite morphogenesis and nociception behavior. We find that smal mutant larvae exhibit thermal hyperalgesia that is fully rescued with a BAC transgene containing smal. Consistent with this phenotype, a smal reporter gene was expressed in nociceptors and other peripheral sensory neurons. Smal::GFP protein localized to punctate structures throughout the cIV md-da neurons. We further show that smal loss-of-function results in reduced nociceptor dendrite branching. Interestingly, mammalian homologues of smal act as collagen receptors, and we find that smal mutant dendrites showed an increase in epidermal cell ensheathment relative to animals that are wild type for smal. Based on this phenotype we propose that Smal protein function is required for attachment of dendrites to the extracellular matrix (ECM) and the loss of activity results in thermal hyperalgesia.

A Framework for Analyzing Residential Fire Outcomes in Homes with Operative Smoke Alarms

Operative smoke alarms have been shown to be effective in reducing home-fire fatalities, but there remain incidents in which injuries and death occur despite the presence of a working smoke alarm. The present work presents a scientifically-guided framework for evaluating the outcomes of such incidents from the perspective of human factors and, specifically, the warnings communication process. It considers the roles of environmental, individual, and situational factors in occupants’ detection, noticing, and processing of smoke alarms, as well as the behaviors produced in response. Such factors include the acoustic environment in which the alarm sounds, the occupants’ cognitive state and focus of attention, the occupants’ developmental and physical abilities, and the situational circumstances in which a response is chosen and executed. The synthesis of these findings provides one methodology for understanding real-world outcomes of fires, as well as informing development and evaluation of countermeasures for improving residential fire fatality rates.