Alarm Response Research Articles

Full-Scale Experimental Study on Influence of Smoke on Pedestrian Movement During Evacuation in Road Tunnel

The article presents the results of experimental studies of evacuation of 50 people from a road tunnel in various smoke conditions. Calculations of total evacuation times, pre-movement times and movement speeds were carried out and the impact of smoke on the speed of movement was analyzed. The pre-movement times, the alarm realization and response times for the subsequent experiments (1, 2 and 3) were 36, 7 and 5 s, respectively. The total evacuation times for 3 experiments were 340, 301 and 215 s. It has been shown that the speed of movement in smoke depends not only on the density of smoke, but also on the very attitude of the experiment participants and knowledge of the tunnel. It has also been shown that the adverse impact of low visibility on the evacuation time and movement speed is as important as the motivation of the evacuees and the effect of learning. In order to collect the observations of the participants, as well as assess potential aspects which might have influenced the process of evacuation, a survey was conducted after both experiments. The answers show that the two main reasons that prompted the evacuation were smoke in the tunnel and the fire drill.

The association between alarm burden and nurse burnout in U.S. hospitals

BackgroundAlarms pervade the hospital environment, often increasing nurses’ workload. Hospital nurses are experiencing burnout at unprecedented rates. PuropseThis study examined the association between nurses’ experience of alarms and burnout. MethodsSurvey data from U.S. nurses (n = 2,131) were analyzed. FindingsNurses who frequently/occasionally experienced overwhelm from alarms had 2.47 (95% CI [1.93, 3.16]) greater odds of high burnout than those who rarely/never experienced alarm overwhelm; those who frequently/occasionally had to delay alarm response had 2.13 [1.67, 2.70] greater odds of high burnout than those who rarely/never did; and those who frequently/occasionally encountered situations where no one responded to an urgent alarm had 2.5 [2.07, 3.03] greater odds of high burnout than those who rarely/never encountered such situations. The associations remained largely unchanged after adjusting for hospital characteristics, nurse practice environment, and nurse staffing. ConclusionAlthough this study was cross-sectional, the potential impact of alarms on nurses’ well-being is an important consideration as technology advances.

Development of integrated monitoring technology for hypothermia and hypoxia in low birth weight infants

Hypothermia and hypoxia are two conditions that often occur in Low Birth Weight (LBW) infants and can lead to serious complications if not promptly detected and addressed. The aim of the research is to develop a prototype of a medical device that integrates the detection of hypothermia and hypoxia in low birth weight infants. The research method uses a Research and Development approach. (R&D). The development process is carried out through several stages, namely needs analysis, design, development, testing, and evaluation. In the needs analysis stage, data is collected based on the results of previous research and through a literature review to determine the expected specifications of the tool. Next, in the design and development stage, the prototype is designed by integrating temperature sensors and an oximeter, as well as an automatic alarm system that provides early warnings when the baby's vital parameters are outside normal limits. In the initial stage, testing is conducted through simulations. The research results show that the prototype is capable of quickly detecting changes in body temperature and oxygen levels, as well as providing an alarm response to any abnormal changes. In further development, functional testing of the device will be conducted on infants. This device is expected to contribute to the improvement of neonatal care quality and the reduction of infant mortality rates due to complications from hypothermia and hypoxia.

Alarm Functions of PD-1+ Brain-Resident Memory T Cells.

Resident memory T cells (TRM cells) have been described in barrier tissues as having a "sensing and alarm" function where, upon sensing cognate Ag, they alarm the surrounding tissue and orchestrate local recruitment and activation of immune cells. In the immunologically unique and tightly restricted CNS, it remains unclear whether and how brain TRM cells, which express the inhibitory receptor programmed cell death protein 1 (PD-1), alarm the surrounding tissue during Ag re-encounter. Using mouse models, we reveal that TRM cells are sufficient to drive the rapid remodeling of the brain immune landscape through activation of microglia, dendritic cells, NK cells, and B cells, expansion of regulatory T cells, and recruitment of macrophages and monocytic dendritic cells. Moreover, we report that although PD-1 restrained granzyme B upregulation in brain TRM cells reactivated via viral peptide, we observed no apparent effect on cytotoxicity invivo, or downstream alarm responses within 48 h of TRM reactivation. We conclude that TRM cells are sufficient to trigger rapid immune activation and recruitment in the CNS and may have an unappreciated role in driving neuroinflammation.

Alarm management approach for supervision of Green Hydrogen Plants

Amid the increasing significance of renewable energy sources, Green Hydrogen Plants (GHPs) have emerged as pivotal contributors to sustainable energy solutions. However, efficient and reliable alarm management in such complex systems remains a significant challenge. This paper presents a novel methodology called V-nets-based alarm management (VBAM), designed to improve supervision by addressing the intricacies of discrete event management in industrial applications such as GHPs. VBAM offers a powerful formalism that integrates visual modeling and temporal patterns, enabling the precise detection and handling of alarms. The proposed methodology is applied to a case study in a GHP, where critical operational parameters are continuously monitored. By analyzing discrete events and their temporal patterns, V-nets facilitate early fault detection, minimize false positives, and optimize alarm response. The theoretical application of VBAM demonstrates its efficacy in improving system safety, reducing downtime, and enhancing overall operational efficiency within GHPs. The contributions of this work to the state of the art include the development of a comprehensive VBAM methodology tailored to GHPs, as well as the theoretical and practical demonstration of its potential impact on alarm management within GHP operations. The outcomes from the experiments showcase the adaptability and effectiveness of VBAM in addressing the complexities of alarm management in GHPs, thereby contributing to enhanced safety, efficiency, and resilience in the operation of GHPs.

Research and Application of Leakage Monitoring Techniques for Gas Field Water Pipelines

Abstract To study the effectiveness and application effects of leakage monitoring techniques for gas field water pipelines in the Sichuan-Chongqing region, seven kinds of flow limitation holes with different diameters were used to simulate the leakage of the gas field water pipeline to carry out a field test. The monitoring conditions of two leakage monitoring techniques, namely dynamic pressure wave compound method and negative pressure wave and transmission balance method, were compared and analyzed under different working conditions. The test results showed that: (1) When the pipeline was full, the leakage with apertures being smaller than 2 mm could not be effectively monitored. A single-end alarm could be achieved using the dynamic pressure wave compound method, but the positioning was ineffective. An alarm could not be effectively achieved using the transmission balance method. (2) When the pipeline was full, for the leakage with apertures being 2 mm and above, early warning could be well achieved using the both methods, and the monitoring effects were nearly the same, with the average positioning error being about 48 m and the average alarm response time being about 58 s. (3) When there were empty pipe slug flows in the pipeline, only apertures being 5 mm and above could be alarmed; however, positioning could not be effectively achieved, and system technical indicators could not be reached. (4) When there were large elevation differences in the gas field water pipeline and empty pipe slug flows could not be eliminated, the both techniques were not applicable.

Multi-Height and Heterogeneous Sensor Fusion Discriminant with LSTM for Weak Fire Signal Detection in Large Spaces with High Ceilings

Fire is a significant cause of fatalities and property loss. In tall spaces, early smoke dispersion is hindered by thermal barriers, and initial flames with limited smoke production may be obscured by ground-level structures. Consequently, smoke, temperature, and other fire sensor signals are weakened, leading to delays in fire detection by sensor networks. This paper proposes a multi-height and heterogeneous fusion discriminant model with a multilayered LSTM structure for the robust detection of weak fire signals in such challenging situations. The model employs three LSTM structures with cross inputs in the first layer and an input-weighted LSTM structure in the second layer to capture the temporal and cross-correlation features of smoke concentration, temperature, and plume velocity sensor data. The third LSTM layer further aggregates these features to extract the spatial correlation patterns among different heights. The experimental results demonstrate that the proposed algorithm can effectively expedite alarm response during sparse smoke conditions and mitigate false alarms caused by weak signals.

Mechanically flexible graphene oxide network for highly-sensitive and ultra-long fire warning

Graphene oxide (GO)-based intelligent fire alarm sensor (FAS) has recently been a sought-after research topic in fire prevention fields. However, it remains a challenge to facilely construct GO-based composite that simultaneously possess mechanical flexibility, excellent flame resistance, highly-sensitive temperature-responsive behavior, rapid fire response and ultra-long fire alarming durability. Here, a nacre-like ternary hybrid paper is conveniently obtained by integrating GO with hexachlorophosphazene-based multi‑hydroxyl molecule (HHACP) and tannic acid (TA) via a facile and eco-friendly water evaporation-induced self-assembly method. The resultant composite paper (TA-GO/HHACP) exhibits mechanically flexible property with tensile strength of 103.7 MPa and toughness of 1.51 MJ/m3, comparable to 2.52 and 5.39 times higher than those of pure GO paper. Further, the TA-GO/HHACP paper displays excellent nonflammability and high-temperature resistance that can withstand continuous butane flame attack (∼ 1200 °C), resulting in ultra-long sustained alarming period of > 1600 s under an open fire. More importantly, benefiting from its rapid electrical resistance reduction capability, such TA-GO/HHACP paper demonstrates ultra-fast fire-triggered response time of ∼ 0.6 s, and ultra-sensitive early fire alarm responses to abnormal high temperatures during pre-combustion process, e.g., ∼ 1 s at 250 °C and ∼ 19 s at 200 °C, respectively, outperforming the best reported GO‑based FAS counterparts. This work provides an inventive paradigm to develop high-performance GO-based intelligent materials with reliable and sensitive early fire-warning function.

Alarm functions of PD-1+ brain resident memory T cells.

Resident memory T cells (T RM ) have been described in barrier tissues as having a 'sensing and alarm' function where, upon sensing cognate antigen, they alarm the surrounding tissue and orchestrate local recruitment and activation of immune cells. In the immunologically unique and tightly restricted CNS, it remains unclear if and how brain T RM , which express the inhibitory receptor PD-1, alarm the surrounding tissue during antigen re-encounter. Here, we reveal that T RM are sufficient to drive the rapid remodeling of the brain immune landscape through activation of microglia, DCs, NK cells, and B cells, expansion of Tregs, and recruitment of macrophages and monocytic dendritic cells. Moreover, we report that while PD-1 restrains granzyme B expression by reactivated brain T RM , it has no effect on cytotoxicity or downstream alarm responses. We conclude that T RM are sufficient to trigger rapid immune activation and recruitment in the CNS and may have an unappreciated role in driving neuroinflammation.

Fire-retardant anti-microbial robust wood nanocomposite capable of fire-warning by graded-penetration impregnation

Wood, renowned for its sustainability, specific strength, and thermal insulation, stands as a highly sought-after sustainable structural material. However, the inherent flammability, decay susceptibility, and inadequate mechanical strength hinder its practical applications in high-rise buildings. Here, we report a groundbreaking solution to fabricate multi-functional fire-retardant wood (M-FRW) through a coupled delignification/impregnation procedure followed by densification treatment. The GO/BA created a hybridized network on the M-FRW surface, while BA molecules penetrated the wood cell. As-created M-FRW exhibits a superior flame retardancy due to the physical barrier and catalytic charring effect of GO/BA, as reflected by an ultrahigh limiting oxygen index value of >75 % and an 85 % reduction in the peak of heat release rate compared to natural wood. Furthermore, the GO/BA layer of M-FRW has a sensitive fire alarm response and ultralong alarm time (∼11280 s). More impressively, M-FRW exhibits an exceptional ability to inhibit decay fungi, mold fungi, and common bacteria due to the superimposed anti-microbial effect of GO and BA. Additionally, M-FRW shows desirable mechanical and thermal insulation properties. This work provides a facile strategy to fabricate a multi-functional advanced wood nanocomposite, making them hold great potential for various engineering applications, such as intelligent buildings.

A multifunctional coating toward wearable superhydrophobic fabric sensor with self-healing and flame-retardant properties with high fire alarm response

The design of wearable fabric with ultrasensitive fire alarm response and piezoresistive sensor capabilities is urgently imperative to prevent burn injuries to people in the fire accident. Herein, a novel cotton fabric-based piezoresistive sensor comprising hydrophobic waterborne polyurethane, polyphosphazene (PPZ) microspheres encapsulated 1H,1H,2H,2H-perfluorooctyltriethoxysilane (FAS), and amino-functionalized carbon nanotubes (A-CNTs) was proposed via a roll coating approach, which achieve self-healing, flame-retardant property, and intelligent fire alarm response. The fabric sensor exhibited prominent flame retardancy because of the synergistic formation of a dense flame-retardant layer on the fabric surface by A-CNTs and PPZ. The char residue of the fabric sensor reached 20.4 wt% at 800 °C, and the limiting oxygen index was as high as 27.4 %. Interestingly, benefiting from the thermoelectric characteristic of A-CNTs, the fabric sensor triggered the fire alarm system within 2 s. More importantly, since the resistance changed with their deformations, the fabric sensor can also monitor a variety of human motions, and its sensitivity (GF) can reach 4.79. Additionally, the resulting fabric sensor exhibited self-healing performance. After physical damage, under near-infrared light irradiation, the healing agent FAS spontaneously migrates towards the surface of the fabric, effectively restoring the superhydrophobic property of the fabric. This work provides new insight into the design and application of multifunctional fabric sensors.

Lethal and sublethal heat-exposure of bed bugs (Cimex lectularius L.) causes alarm pheromone emission and elicits a movement response in nearby recipients

Many gregarious insect species use aggregation and alarm pheromones. The bed bug, Cimex lectularius L., emits an alarm pheromone (AP), a 70/30 blend of (E)-2-hexenal and (E)-2-octenal, when threatened. Bed bugs avoid temperatures above 43 °C, which are lethal to bugs and used commercially as spatial heat treatments to manage infestations. However, the interaction of bed bug AP in heat avoidance has not been investigated. The goal of this research was to: 1) determine if bed bugs emit AP as an alarm response to heat exposure, and 2) quantify the behavioral responses of conspecifics to AP emitted by heat-exposed bed bugs. Using a selected ion flow tube mass spectrometer, we found that bed bugs responded to lethal and sublethal heat exposure by emitting AP. The Harlan laboratory population emitted more pheromone than a laboratory adapted field population from Florida (McCall). Harlan females emitted the most AP, followed by Harlan males, McCall females and males. In separate behavioral experiments, we showed that conspecifics (i.e., recipients) reacted to AP released by heat exposed bed bugs (i.e., emitters) by frantically moving within 50 mm and 100 mm test arenas. The Harlan recipients reacted to AP in 100 mm areas, whereas the McCall strain did not, indicating a short area of effectiveness of the AP. Synthetic AP components tested in behavioral experiments caused identical effects as the natural AP blend released by heat-exposed bed bugs.

Ototoxicity of polystyrene nanoplastics in mice, HEI-OC1 cells and zebrafish.

Polystyrene nanoplastics are a novel class of pollutants. They are easily absorbed by living organisms, and their potential toxicity has raised concerns. However, the impact of polystyrene nanoplastics on auditory organs remains unknown. Here, our results showed that polystyrene nanoplastics entered the cochlea of mice, HEI-OC1 cells, and lateral line hair cells of zebrafish, causing cellular injury and increasing apoptosis. Additionally, we found that exposure to polystyrene nanoplastics resulted in a significant elevation in the auditory brainstem response thresholds, a loss of auditory sensory hair cells, stereocilia degeneration and a decrease in expression of Claudin-5 and Occludin proteins at the blood-lymphatic barrier in mice. We also observed a significant decrease in the acoustic alarm response of zebrafish after exposure to polystyrene nanoplastics. Mechanistic analysis revealed that polystyrene nanoplastics induced up-regulation of the Nrf2/HO-1 pathway, increased levels of malondialdehyde, and decreased superoxide dismutase and catalase levels in cochlea and HEI-OC1 cells. Furthermore, we observed that the expression of ferroptosis-related indicators GPX4 and SLC7A11 decreased as well as increased expression of ACLS4 in cochlea and HEI-OC1 cells. This study also revealed that polystyrene nanoplastics exposure led to increased expression of the inflammatory factors TNF-α, IL-1β and COX2 in cochlea and HEI-OC1 cells. Further research found that the cell apoptosis, ferroptosis and inflammatory reactions induced by polystyrene nanoplastics in HEI-OC1 cells was reversed through the pretreatment with N-acetylcysteine, a reactive oxygen species inhibitor. Overall, our study first discovered and systematically revealed the ototoxicity of polystyrene nanoplastics and its underlying mechanism.

Alarm rationalization and dynamic risk analyses for rare abnormal events

In this paper, improved alarm rationalization strategies are introduced to evaluate the quality of the multivariate alarm systems developed in previous work – with the alarm thresholds and response actions modified appropriately, based on key statistical metrics. For an exothermic CSTR, our strategies resulted in a significant reduction in the number of nuisance alarms, focusing on only quality alarms, which, if ignored, are more likely to result in an abnormal shift in operation to the undesirable regions. Next, their real-time performance is evaluated using dynamic risk analysis (DRAn), in which, the associated risk is analyzed by estimating the failure probabilities of the multivariate alarm systems using Bayesian statistics, based on multiple dynamic simulations for the process, inclusive of control, alarms and response actions. As expected, the failure probability distribution developed for the exothermic CSTR has a much lower variance as compared to one developed using a flat prior distribution.

Effect of soldiers on vibroacoustic alarm response in workers of subterranean termites (Blattodea: Rhinotermitidae)

Effect of soldiers on vibroacoustic alarm response in workers of subterranean termites (Blattodea: Rhinotermitidae)

Mechanistic modeling of alarm signaling in seed-harvester ants.

Ant colonies demonstrate a finely tuned alarm response to potential threats, offering a uniquely manageable empirical setting for exploring adaptive information diffusion within groups. To effectively address potential dangers, a social group must swiftly communicate the threat throughout the collective while conserving energy in the event that the threat is unfounded. Through a combination of modeling, simulation, and empirical observations of alarm spread and damping patterns, we identified the behavioral rules governing this adaptive response. Experimental trials involving alarmed ant workers (Pogonomyrmex californicus) released into a tranquil group of nestmates revealed a consistent pattern of rapid alarm propagation followed by a comparatively extended decay period [1]. The experiments in [1] showed that individual ants exhibiting alarm behavior increased their movement speed, with variations in response to alarm stimuli, particularly during the peak of the reaction. We used the data in [1] to investigate whether these observed characteristics alone could account for the swift mobility increase and gradual decay of alarm excitement. Our self-propelled particle model incorporated a switch-like mechanism for ants' response to alarm signals and individual variations in the intensity of speed increased after encountering these signals. This study aligned with the established hypothesis that individual ants possess cognitive abilities to process and disseminate information, contributing to collective cognition within the colony (see [2] and the references therein). The elements examined in this research support this hypothesis by reproducing statistical features of the empirical speed distribution across various parameter values.

Neurocognitive Features of Mild Cognitive Impairment and Distress Symptoms in Older Adults Without Major Depression.

Two distinct symptom dimensions were identified in older adults who did not have major depressive disorder (MDD): a) a dimension associated with mild cognitive dysfunction, and b) a dimension related to distress symptoms of old age (DSOA). It is uncertain whether previous findings regarding the features of amnestic mild cognitive impairment (aMCI) remain valid when patients with MDD are excluded. To examine the neurocognitive features of aMCI (n = 61) versus controls (n=59) and the objective cognitive characteristics of DSOA in participants without MDD. Neurocognition was evaluated utilizing the Cambridge Neurological Test Automated Battery (CANTAB) and memory tests. This research demonstrated that CANTAB tests may differentiate between aMCI and controls. The One Touch Stockings of Cambridge, probability solved on first choice (OTS_PSFC), Rapid Visual Information Processing, A prime (RVP_ A´), and the Motor Screening Task, mean latency, were identified as the significant discriminatory CANTAB tests. 37.6% of the variance in the severity of aMCI was predicted by OTS_PSFC, RVP_ A´, word list recognition scores, and education years. Psychosocial stressors (adverse childhood experiences, negative life events), subjective feelings of cognitive impairment, and RVP, the probability of false alarm, account for 40.0% of the DSOA score. When MDD is ruled out, aMCI is linked to deficits in attention, executive functions, and memory. Psychosocial stressors did not have a statistically significant impact on aMCI or its severity. Enhanced false alarm response bias coupled with heightened psychological stress (including subjective perceptions of cognitive decline) may contribute to an increase in DSOA among older adults.

Subterranean termites raise the alarm when their anti-fungal weapon falters.

Termicin is an anti-fungal defensin that is disseminated from termite salivary glands. The peptide appears to be critical for the elimination with mutual grooming (allogrooming) of pathogenic spores (conidia) that have attached to the insect cuticle. There has been a recent selective sweep for an advantageous variant of this peptide in the subterranean termite Reticulitermes flavipes. We tested the anti-mycotic activity of a recombinant termicin corresponding with this variant against the conidia of different Metarhizium fungal isolates from soil close to foraging R. flavipes workers. Termicin was most effective against isolates that had previously been shown to elicit a relatively weak alarm response, as indicated by brief bouts of rapid longitudinal oscillatory movement (LOM). These isolates that elicited weak alarm were also the deadliest apparently because the survival of termites exposed to the fungus depends on a strong social immune response (LOMs and allogrooming). The selective pressure for a single termicin variant may have been driven by the most dangerous isolates that elicit a weak behavioral response. The correlation between termicin anti-fungal activity and LOM suggests that pathogen-associated molecular patterns that affect termite recognition of conidial contamination and the onset of elevated allogrooming also affect the vulnerability of conidia to the disruption of their cell membranes by termicin.

Color adjustable, mechanically robust, flame-retardant and weather-resistant TiO2/MMT/CNF hierarchical nanocomposite coatings toward intelligent fire cyclic warning and protection

Fire safety and protection are very important but still show a critical global challenge. Developing smart fire warning materials with combined passive flame retardancy and active fire alarm response is promising for reducing or avoiding serious fire disasters. Various nano-fillers (e.g., graphene oxide and MXene) based composite coatings have proven to be effective for monitoring critical fire risk of various combustible materials; however, they still show some shortages, for example, high cost, black color, poor weather resistance and complicated fabricating process. Here, we report a green, cost-effective and large-scale strategy for fabricating water-based 3D-titania/2D-montmorillonite/1D-celluose nanofiber (TiO2/MMT/CNF) hierarchical nanocomposite coatings with adjustable color, mechanical robustness, good flame retardancy, long-term weather resistance and sensitive fire cyclic alarming response. The formation of strong chemical bonding and hydrogen bonding interactions among polyethylene glycol molecules and multi-scale nano-fillers together with silane surface modification can produce good mechanical flexibility (folded crane), surface hydrophobicity (water contact angle of 152°) and exceptional flame resistance (good structure integrity after 120 s flame exposure). Notably, the optimized nanocomposite coatings exhibit ultrafast fire alarm response (<3.5 s) and stable fire cyclic alarming capability via the possible band transition of the TiO2 network under flame. Further, such color-adjustable nanocomposite coatings can be easily fabricated for large-scale production, and they show excellent stable flame retardancy and stable fire cyclic warning response even after more than one-year outdoor exposure. This work provides a promising and green fire-warning nanocomposite coatings with combined passive-active functionalities for fire warning and protection.

Multivariate alarm systems to recognize rare unpostulated abnormal events

AbstractMost chemical and manufacturing plants have safety/reliability systems in place that are well equipped to handle commonly occurring postulated abnormal events, but often prove to be ineffective in predicting highly unanticipated and randomly occurring unpostulated abnormal events. In this paper, an advisory system is developed to analyze and recognize such events, consisting of novel, multivariate alarm systems and response actions introduced using process modeling and path‐sampling for unpostulated abnormal events. It augments existing safety/reliability systems, suggesting actions when unanticipated abnormal events are approached. Forward‐flux sampling (FFS), developed to discover rare molecular dynamics pathways, is applied. With an approximate process model, for an exothermic continuous‐stirred tank reactor using a perturbed feed concentration, the FFS algorithm is applied to identify rare trajectories between high‐conversion and low‐conversion steady‐states, with key process variables saved at various “crossing points.” Then, committer probabilities, , are computed at each crossing point, yielding a mathematical model that expresses as a function of the key process variables; that is, the reactor temperature (T), cooling‐water flow rate (), and cooling‐water temperature (), selected as choices for the primary alarm variables. For these, alarm thresholds; that is, L—low, LL—low low, and LLL—low low low, are suggested by computing their critical ranges, given the ranges for every alarm threshold.