bluuebunny/crossref_metadata_2025 huggingface dataset:
Event-triggered optimal control with finite-time convergence critic networks for input-constrained nonlinear systems
Authors: Liu Yizhuo , Ma Kemao
Published: November 2024

This paper proposes an adaptive critic design-based event-triggered optimal control method for input-constrained continuous-time nonlinear systems. Adaptive critic design is a special framework of adaptive dynamic programming that approximates the value function by a critic neural network and derives the approximate optimal control policy through analytical methods. The proposed adaptive critic design considers the control input constraints by introducing a non-quadratic cost function and employs an event-triggered mechanism to reduce the number of controller executions. Unlike the existing event-triggered adaptive critic design, this paper proposes a novel finite-time adaptive law based on regression filtering scheme. The adaptive law utilizes the error information of the network weights to ensure fast convergence to the optimal control law under the event-triggered mechanism, which improves the real-time performance of the system. Additionally, explicit bounds for each parameter in the compact set and the specific convergence time estimates are provided in the convergence analysis. Finally, the effectiveness and practicality of the proposed method for real-time online applications are validated through two simulation examples.
Hunting nonstandard neutrino interactions and leptoquarks in dark matter experiments
Authors: Schwemberger Thomas , Takhistov Volodymyr , Yu Tien-Tien
Published: November 2024

Next generation direct dark matter (DM) detection experiments will have unprecedented capabilities to explore coherent neutrino-nucleus scattering (CEνNS) complementary to dedicated neutrino experiments.
We demonstrate that future DM experiments can effectively probe nonstandard neutrino interactions (NSI) mediated by scalar fields in the scattering of solar and atmospheric neutrinos. We set first limits on S
1 leptoquark models that result in sizable μ - d and τ - d sector neutrino NSI CEνNS contributions using LUX-ZEPLIN (LZ) data. As we show, near future DM experiments reaching ∼ 𝒪(100) ton-year exposure, such as argon-based ARGO and xenon-based DARWIN, can probe parameter space of leptoquarks beyond the reach of current and planned collider facilities. We also analyze for the first time prospects for testing NSI in lead-based detectors.
We discuss the ability of leptoquarks in the parameter space of interest to also explain the neutrino masses and (g-2)
μ
observations.
p-wave mesons emitting weak decays of bottom mesons
Authors: Kaur Maninder , Singh Supreet Pal , Verma R. C.
Published: November 2024

This paper is the extension of our previous work entitled ''Searching a systematics for nonfactorizable contributions to

and

hadronic decays''. Obtaining the factorizable contributions from the spectator-quark model for

a systematics was identified among the isospin reduced amplitudes for the nonfactorizable terms among

decay modes. This systematics enables us to derive a generic formula to help predict the branching fractions for

decays. Inspired by this observation, we extend our analysis to p-wave meson emitting decays of

meson

particularly

, which have similar isospin structures and make predictions for

decays, for which experimental measurements are not yet available.
Assessing fire and explosion hazards in biomass: insights and emerging challenges
Authors: Fernandez-Anez Nieves , Hagen Bjarne C. , Amez Isabel , Tascon Alberto , Castells Blanca
Published: November 2024

Solid biofuels are one of the main energy industries, where fire and explosions have occurred during the last decades. This industry continues growing, however, the fundamental understanding of these materials is still limited and far from what is needed to ensure a safe working environment. A complete characterization of materials is essential to address this point, but a complete framework has not been developed. Different methodologies, testing parameters, testing equipment, etc. are used depending on the laboratory or the facilities. This lack of procedures introduces high uncertainties in the field, that are increased by the common idea of comparing results from different procedures without being consistently gathered. This problem has been detected when studying several characteristics of biomass: composition, particle size, particle shape, thermogravimetric analysis are examples of these situations. A complete review and the development of new standards to standardize the situation are pressing and should be addressed in the near future.
Lateral Flame Spread Over Thermally Thin Fuels: Theoretical Prediction of Flame Spread Rate and Experimental Validation
Authors: Bhattacharjee Subrata , Panzer Felix
Published: November 2024

Flame spread over solid fuel is a fundamental problem in fire safety science. Although it has been studied in different orientations – downward, upward, horizontal, and lateral – closed-form formula for predicting the flame spread rate is only available for opposed-flow configuration and has been experimentally verified in downward configuration, a special case of opposed-flow flame spread. In this work we present a simplified theory to predict the flame spread rate when a vertical flame spreads sideways (laterally) on both sides (symmetrically) of a thermally thin sample held horizontally in a quiescent normal-gravity environment. The ratio of flame spread rates between the lateral and downward orientations are shown to depend only on the flame coefficient, a non-dimensional known temperature ratio, and the Prandtl number. Experiments are performed in both downward and lateral configurations with a series of samples with fuel thickness ranging from 400 through 1500 µm and width from 10 through 60 mm as parameters. The spread rate ratio between the two configurations is compared to the theoretical prediction with reasonable agreement. As predicted by the theory, the spread rate ratio is found to be independent of fuel thickness and fuel width for laminar flame spread.
Conditions for the onset of char oxidation in timber
Authors: Schmidt Laura , Hadden Rory M
Published: November 2024

Smouldering combustion poses fire safety hazards for timber construction, particularly after the extinction of the flaming compartment fire. The conditions under which smouldering can be initiated and sustained are of interest in quantifying this hazard. Smouldering involves the simultaneous processes of pyrolysis and char oxidation; however, studying them together introduces challenges as they are highly coupled. Separating these processes by using char instead of virgin timber allows char oxidation to be studied in isolation from other processes. Char was generated anaerobically at 400 °C in a muffle furnace. Char oxidation did not occur at 7 kW/m2. Incipient char oxidation was apparent in 1/3 cases at 8 kW/m2 and 2/3 cases at 9 kW/m2. At 10 kW/m2, all samples showed a distinct onset of char oxidation. Temperature measurements showed that non-reacting samples behaved similarly to an inert heated solid, except for some moisture evaporation, reaching steady state temperatures after 30 min. The temperature 2 mm beneath the surface exceeded 200°C when char oxidation occurred and reached up to 490 °C, which correlates well with the main oxidation temperature range of this char of 350 °C to 490 °C found through thermogravimetric analysis. The onset of char oxidation was characterised by a rapid increase in carbon generation (up to 0.0039 g/s CO and 0.0097 g/s CO2, which equals 0.23 g/min and 0.58 g/min, respectively) and a heat release rate of approximately 53 kW/m2.
A Comprehensive Model for Wood Pyrolysis Incorporating Detailed Chemical Reactions and Porous Medium Interactions
Authors: Cuong Dinh Duy , Richard Franck , Batiot Benjamin , Rogaume Thomas
Published: November 2024

A comprehensive model for wood pyrolysis has been developed. This model integrates detailed chemical reactions and interactions between chemistry, heat, and mass transfers within the porous medium. The Ranzi’s reaction scheme [1] is well-known for its detailed and comprehensive modelling of wood components (cellulose, hemicellulose, and lignin). This work extends Ranzi’s scheme to include secondary reactions for tars, which cannot be neglected when wood samples behave as thermally thick materials, as is often the case during fire scenarios involving woody materials. A novel aspect of this model is its detailed consideration of gas-solid interactions within wood pores, incorporating mass and heat transfer mechanisms. The model is based on the PATO code (Porous Analysis Toolbox based on OpenFOAM), which treats the porous medium as a continuum by using a homogenization process to establish conservation equations for averaged quantities defined on a Representative Elementary Volume (REV). This model is applied to simulate cone calorimeter experiments of wood thermal decomposition in a nitrogen-rich environment, providing detailed insights into the complex interplay of chemical and physical processes during pyrolysis. The results highlight the model’s potential as a powerful tool to predict wood thermal decomposition in cases of thermally thick sample behavior, where secondary tars reactions play a key role in describing the entire dynamics of the pyrolysis process at high temperatures.
Effect of flow velocity, atmosphere and sample thickness on the mass loss rate of PMMA in the tube furnace
Authors: De Lannoye K , Belt A , Hasalová L , Arnold L
Published: November 2024

The experiments in this contribution have been conducted in an adapted tube furnace, a new gram scale experiment, based on the ISO 19700, in which an online mass loss measurement has been installed. The benefit of this set-up is that it allows to conduct gram-scale pyrolysis experiments under well-defined boundary conditions. In this set-up, samples with a length up to 50 cm can be investigated under different atmospheres and flow rates. In this contribution, the effect of several experiment parameters on the mass loss rate is studied. For this purpose, black cast PMMA samples were heated at a constant heating rate of 5 K/min. The atmosphere as well as the flow rate through the tube furnace were varied. Additionally, samples with different thicknesses were tested. It was observed that unless the sample auto-ignites, different flow rates do not result in differences in the mass loss rate. Nitrogen versus air atmosphere does make a significant difference on the mass loss rate. Under air atmosphere the PMMA reacts at lower temperature than under nitrogen atmosphere. The thicker the sample, the more the peak mass loss rate shifts to higher temperature and the lower the normalised peak mass loss rate.
Autoignition-based simplified kinetic models of hydrocarbon oxidation for fire simulations
Authors: Moorthamers Y. , Snegirev A. , Maragkos G. , At Thabari J. , Merci B.
Published: November 2024

The possibility of a global reaction model to predict the autoignition delay times of stoichiometric fuel-air mixtures with the accuracy corresponding to that obtained using the most comprehensive chemical mechanisms is demonstrated. To make the global reaction model applicable in a wide temperature range, the effective kinetic parameters are set temperature dependent. These parameters are derived for alkane (from methane to n-heptane and alkene (ethylene and propylene) fuels. Complicated and non-monotonic dependencies of autoignition delay time on temperature, such as those in which an interval with negative temperature dependence exist, are replicated. Compared to the detailed chemical mechanisms, use of the global reaction model offers considerable reduction of computational cost yet retaining capability of predicting critical phenomena of flame extinction and re-ignition in under-ventilated or strained flames.
Experimental and Numerical Study on Fire Suppression via Water Mist in a Mechanically Ventilated Compartment
Authors: Acherar Lahna , Wang Hui-Ying , Coudour Bruno , Pierre Garo Jean
Published: November 2024

The present work provides a detailed experimental and numerical study on suppression phenomena via water mist of a buoyant, turbulent fire over liquid (heptane) surface. It is found that water mist in a hot confined environment allows to achieve maximum droplet evaporation in the smoke layer, and however, it does not conduct to suppression of a fully developed fire due to re-ignition of unburnt fuel. Through the analysis on HRR, gas temperature, heat flux and chemical species, it is concluded that in a hot environment, a consecutive efficient cooling of smoke layer leads to the fire suppression only at lower ACPH (Air Change Per Hour) via lack of oxygen.
A Basic Study on the Temperature Characteristics of the Top of the Rack-type Warehouse Combustibles
Authors: Kim YunSeong , Kang Hyun , Kweon OhSang
Published: November 2024

The temperature characteristics of the fire plume rising above combustibles were examined through experiments simulating fires that occur in combustibles stored in a rack. The fire plume temperature rising above the combustibles was proportional to three times the dimensionless distance r/z, and the average temperature distribution according to the dimensionless distance showed that the edge temperature at 3.6 m was higher than the temperature at 1.2 m and 2.4 m due to the influence of the ceiling.
Burning Rate and Carbon Monoxide Production for an elevated pool fire in a weakly ventilated compartment
Authors: Georges E , Pretrel H , Varrall K , Vauquelin O
Published: November 2024

This work concerns the study of fires in ventilated compartments, and in particular scenarios involving fire located in the upper part of a room near ceilings in under-ventilated conditions. A reduced-scale experimental study with dodecane pool fires was carried out to investigate the combined influence of fire elevation and compartment ventilation flowrate. The fire characteristics of interest are burning rate and CO production. The results show that fire elevation and ventilation flow rate have opposite influence on burning rate. The net balance is a positive effect of elevation, increasing the burning rate even in an oxygen-poor environment. On the contrary, elevation and ventilation flowrate have the same positive influence on CO production and contribute to its increase. This work shows the complexity of a fire in the upper part of a poorly ventilated room and provides new knowledge to improve its prediction for safety assessments.
Zone modeling of timber compartment fires with increasing combustible surfaces: modification to the Semenov’s model
Authors: Calderón I. , Calderón-Vásquez I. , Battisti F. G. , Majdalani A. H. , Jahn W.
Published: November 2024

The traditional compartment fire framework has been the safety standard in fire engineering codes and design standards. Incorporating potentially combustible materials has led to reevaluating the foundations of this science. A simplified compartment fire model is proposed, modifying Semenov’s model to quantify the fuel contribution of an exposed timber element to the compartment fire and determine the impact of this variable on the occurrence of a flashover. By involving a time-dependent component, the proposed model behavior approaches experimental observations. The overall results show that the larger the fuel surface area, the more certain flashover will occur.
Thermal characterization of downward ventilation flows through a smoke layer
Authors: Perrin Loïc , Pretrel Hugues , Varrall Kevin , Vauquelin Olivier
Published: November 2024

Understanding the behaviour of downward flows of fresh air in temperature-stratified compartments is crucial for improving oxygenation of fire in confined compartment. This study investigates the axial temperature profiles of such flows and their sensitivity to injection rates. Experimental tests in a stratified compartment reveal a naturally bounded flow that transitions between a plume and a collapsing fountain, with the ability to transport heat and to affect the thermal stratification. However, different injection rates reveal potential distinct flow configurations. Low rates limit heat transfer potential to upper locations, while high rates lead to colder air reaching the lower part of the compartment. These findings highlight the significance of injection conditions in predicting the fire source environment. Improving such predictions is critical for ensuring accurate prediction of oxygen concentration in the near field of a fire.
Natural Convection on a Vertical Surface: Direct Numerical Simulation versus Empirical Correlations
Authors: Dehghani P. , Chaudhari D. M. , DiDomizio M. J.
Published: November 2024

Convective heat flux to surfaces is an essential component of fire safety analyses. Heat transfer from fires to surfaces by natural convection is typically represented in fire models using empirical correlations; however, these models are often constrained by specific experimental conditions and may not universally apply to all scenarios. A universal correlation that considers all influential variables has yet to be established. The limitations of these models for convective heat transfer, and their suitability for fire modelling, must be identified. This study performs a comprehensive evaluation of prominent natural convection correlations from the literature against a benchmark dataset. The primary objective was to examine the existing correlations quantitatively, and adjust the correlations using a universal and systematic approach. Direct numerical simulation was employed to investigate convective heat transfer on a vertical plate in a still ambient, and simulation results were validated against experimental data. Predictions of the natural convection correlations were then compared to the simulation results, and their effectiveness over differing ranges of Rayleigh numbers and surface temperatures was evaluated. Correction factors were determined to improve the accuracy of the top-performing correlations in each flow regime, thereby enhancing their applicability in fire safety.
Impact of Oxygen Concentrations on the Development of Fires in Ventilation Limited Environments
Authors: Lakhani Ayaan , DiPaola Alexander , Senez Peter , Weckman Elizabeth
Published: November 2024

Large-scale fire tests at the University of Waterloo compare behaviour of a Canadian non-fire retardant faux leather couch and a UK fire-retardant faux leather couch of the same construction under ventilation limited conditions. Results reveal that both fuel loads reach maximum, but different, mass loss rates at minimum oxygen concentration in the environment. Following this, they document the rapid decay in fuel mass loss rate with consequent decrease in temperature through the burn structure. Time-varying volatile organic compounds and carbon monoxide data show preferential increase in concentration as combustion efficiency decreases. The paper adds novel time varying, simultaneously collected fuel mass, temperature and concentration data with aim to provide new insight into the full evolution of compartment fires through transition from early growth to ventilation limited conditions and subsequent fire decay.
Experimental study of fire propagation along a vertical wall in a lab scale device
Authors: Di Giorgio F. , Galizzi C. , Kühni M.
Published: November 2024

A Characterization study was conducted out on a novel experimental apparatus designed for investigating the spread of façade fires. This setup features a wall divided into an effusion zone, where methane injection mimics the pyrolysis process, and a substantial inert zone where the flame propagates. Various flow rates were applied to the effusion module and compared using direct visualizations, CH* and OH* chemiluminescence imaging, as well as temperature, heat flux and velocity measurements. These analyses underscore and validate the well-documented impact of fuel injection rates on flame characteristics and propagation. This standardized configuration establishes a benchmark case, pivotal for comparing with more complex scenarios involving alternative arrangements of effusive and inert zones. Furthermore, the data generated in this study furnish a foundation for assessing the reliability of fire engineering codes.
Sensitivity of wildfire modelling to physical parameters
Authors: Richards Imogen , Restuccia Francesco
Published: November 2024

This paper explores the sensitivity of a fire model to various physical parameters. Models can provide valuable insights into fire behavior, and understanding how sensitive these models are to their inputs is crucial for assessing the impact of data quality. Based on experiments and modelling of piloted ignition of live forest fuels, Fire Dynamics Simulator is used to model a lab-scale fire, with pine needles representing the fuel on a forest floor, under external radiation and forced convection conditions. The sensitivity of the model is analysed using scatter and one-at-a-time analyses. The model results are characterised using the outputs peak heat release rate (pHRR) and time to peak heat release rate. The analysis showed that over the eight studied parameters, the most significant ones affecting time to pHRR were emissivity and fuel moisture content, whilst bulk density and moisture content affected pHRR value most. Overall the parameters which had the greatest effect on the outputs were fuel moisture content and fuel element surface-volume ratio.
Citizen responsive contributions in wildfire crisis Lessons about Shared Responsibility from the 2021 Finsjö fire
Authors: Hovart Lucas , Eriksson Kerstin , Frykmer Tove , McNamee Margaret
Published: November 2024

In 2021, the village Finsjö in Sweden experienced an abnormally large wildfire. During an intervention lasting for 6 days, Fire and Rescue Services [FRS] received spontaneous help from volunteers, leading to valuable contributions but also questions regarding how to address division of responsibilities. Through qualitative interviews with the FRS, this study explores the interaction between formal and informal responsibilities and how FRS representatives perceive spontaneous volunteer contributions. We will show how informal response benefits come from complementing formal duties by answering to specific kinds of needs, and how challenges emerge from questions of dependence and accountability.
Simulation of Complete or Incomplete Biomass Degradation under Parameterized Wildland Fire Spread Conditions
Authors: Mohsen Ahmed Mohamed , Al-Bulqini Hazem M. , Trouvé Arnaud , Forthofer Jason , Finney Mark
Published: November 2024

Our objective in the present study is to provide fundamental insights into the main factors that control the thermal degradation processes occurring inside the biomass vegetation during wildland fire spread. These processes determine the formation of flammable volatiles through pyrolysis reactions and the intensity of the internal heat release through char oxidation reactions; both aspects are central to flaming and smoldering combustion. We adopt here a simplified framework in which the biomass vegetation is viewed as a population of discrete elongated particles that are made of pine wood, are cylindrical-shaped and feature different diameters. The exposure conditions experienced by these particles in an assumed fire are characterized by a given intensity of the external thermal load, a given duration during which this load is applied, and a given external flow velocity that controls the rates of convective heat transfer and oxygen mass transfer. The response of the biomass particles is studied using a one-dimensional computational model, called the particle burning rate (PBR) model. The PBR model adopts a porous medium formulation, and provides a description of drying, (thermal and oxidative) pyrolysis, and char oxidation. We focus in the present study on the conditions required for complete “fuel consumption”, i.e., for complete particle degradation from virgin solid to ash. It is found that in thin biomass particles, complete biomass degradation requires sufficiently high intensities of the external thermal load and sufficiently low external flow velocities; high flow velocities correspond to excessive cooling effects. Similarly, in thick biomass particles, complete biomass degradation requires sufficiently high intensities of the external thermal load, sufficiently long application times of the thermal load, and sufficiently high external flow velocities; low flow velocities correspond to insufficient oxygenation of the (exothermic) oxidative pyrolysis and char oxidation reactions.
Extinction of gas burner with minimum water flow rate discharge from a water mist
Authors: Lapillonne Lucie , Collin Anthony , Mehaddi Rabah , Russo Patrice , Truchot Benjamin
Published: November 2024

Fire extinguishing systems tend to be optimized by impinging a reduced amount of water, with controlled droplet diameter distribution. This paper investigates the minimum water flow rate required for extinguishing a fire experimentally. A gas burner is placed under a water mist nozzle to expose the fire to a controlled water discharge, gradually increasing the volumetric flow rate injected. The water mist consists of a full cone jet, generated thanks to a single nozzle, with a 100 to 300 μm particle diameter. One of the specific characteristics of water mist is the injection of small particle diameters. Thanks to their high exchange surface between droplets and the ambient, the evaporation rate is increased, which contributes to facilitating fire extinction. The main mechanisms involved in the extinction process are the cooling of the reaction zone and the reduction of the oxygen concentration by putting steam directly in this reaction zone. Some research works were published to correlate the required water flow rate to extinguish a fire but based on small-scale tests, typically with HRR lower than 50 kW. This paper aims to check whether or not these relations can be applied to higher heat release rates and higher flow rates in order to determine the critical water flow rate that extinguishes the fire. A set of normalized parameters have been used to comprehend the extinction phenomenon and to analyse the experimental data. The tendency of averaged results shows a predictable extinction rate and consolidates literature data.
Detecting Firefighter’s Thermal Risks in a Commercial Building Structure Using Machine Learning
Authors: Tong Qi , William Stroup David , Cheong Tam Wai , Fang Hongqiang
Published: November 2024

A multi-input and multi-output (MIMO) machine learning model is developed to simultaneously detect firefighter’s thermal risks in a commercial building structure. A total of 2,000 numerical experiments with a wide range of fire and ventilation scenarios are carried out using Fire Dynamics Simulator. Temperature data is obtained from sensors over a simulation duration of 900 s with a 5-s time step. A dataset consisting of 242,000 instances is constructed. The instances are labeled by four thermal operating conditions and are pre-processed for the purpose of training, validating, and testing a machine learning model. Model performance of the MIMO model is provided, and it is benchmarked against typical multi-input and single-output (MISO) machine learning models in terms of accuracy and computation time. Results show that the MIMO model can provide the same accuracy as MISO in detections of thermal operating conditions at multiple locations simultaneously but 10 times faster in computation than MISO. MIMO achieves almost the same recall and precision as MISO except for two locations with binary classes caused by fluctuations in the labels. This research demonstrates the potential of using machine learning methodologies to develop practical firefighting applications which can, in turn, enhance firefighters’ situational awareness and improve their safety measures during firefighting and/or carrying out search-and-rescue in a large commercial building structure.
Foam concentrate rheology and foam system design
Authors: Meyer David J , Herrera Diaz Luis , Dlugogorski Bogdan Z
Published: November 2024

NFPA and EN design standards for systems of firefighting foams devolve the problem of flow calculations for each foam concentrate to the product manufacturers. The data provided by manufacturers do not represent the engineering specifications needed for foam system design. This contribution examines the rheology of foam concentrates, comprising three FfreeF (fluorine-free foams) and one AR-AFFF (alcohol-resistant aqueous film-forming foam). These foam concentrates comprise solutions of polymers (predominantly polysaccharides) combined with surfactants and solvents. We reveal that all products exhibit significant shear thinning and that the formulations display substantial yield stress and slow response to changes in stress. These foam concentrates are sensitive to shearing and require many hours to recover from any deformation during handling. These non-Newtonian properties of the concentrates arise mainly from the presence of polysaccharides in their chemical make-up. We provide guidance for the types of measurement needed to provide engineering specifications for fire system designers and the limits of use for these measurements. The contribution highlights the design implications of the slow-yielding foam concentrates for design of foam-based fire-suppression systems.
On the increase of carbon monoxide production during fire suppression with a water mist spray
Authors: Miyanoiri Yuta , Tanaka Futoshi , Beji Tarek
Published: November 2024

The paper presents an experimental study on fire suppression using a water mist spray. The fire source is a circular propane gas burner with diameters between 0.15 m and 0.25 m, and corresponding to theoretical heat release rates between 3.7 and 40.2 kW. The water mist nozzle with an orifice diameter of 0.69 mm diameter was positioned at 1 m above the fire source and delivered water flow rates between 0.15 and 0.76 L/min. The volume-median diameter of the water droplets ranged between approximately 172 and 242 μm. The whole assembly was under a hood to collect and analyse the combustion products. In this paper, the analysis is focused on carbon monoxide production during water spray activation. The results show that the CO yield can increase by up to 14 times in comparison to the values without a water spray. A preliminary Computational Fluid Dynamics (CFD) simulation using a two-step chemistry mechanism with finite-rate chemistry for CO oxidization has shown qualitatively promising results in capturing the experimental trends.
Fire Protection Systems functional safety requirements in performance-based design: proposed workflow and a simple case application
Authors: Fiorentini Luca , Cancelliere Piergiacomo
Published: November 2024

According to the Italian Fire Code DM 03/08/2015 (IFC), the performance-based design with the Fire Safety Engineering (FSE) approach can be used whenever the deemed to satisfy solution cannot be put in place. When using FSE approach in an alternative solution, it is mandatory to demonstrate that, starting from a given fire risk level, the level of performance of the safety measures in the considered global strategy satisfies the fire safety goals. Since it’s possible to limit the Heat Release Rate (HRR) curve with automatic fire protection systems activation, according to the latest issue of the IFC DM 18/10/2019, these systems are considered safety critical systems since they operate a significant risk reduction and so “higher availability systems” (HAS) must be installed. This paper aims to describe how functional safety principles can be applied to the design of fire protection systems used in FSE-based design. Functional safety principles will be employed for designing a fire protection system whose reliability is quantitatively assessed and in line with the specific requirements of HASs.
Perspectives of stakeholders on tourist vulnerability to wildfires in cross-border regions
Authors: Ronchi Enrico , Vaiciulyte Sandra
Published: November 2024

This paper presents findings from a qualitative study on tourist vulnerability in wildfire scenarios considering the perspectives of tourist infrastructure owners/managers, fire and rescue service, municipality managers, researchers, and other emergency managers in Spain-France border regions. Through a thematic analysis of twenty survey responses, this study presents the critical factors influencing tourist vulnerability. Three key themes were identified, namely 1) Lack of knowledge, 2) Physical vulnerability, and 3) Discrepant tourist expectations. These themes highlight the urgency of educating tourists on self-protection measures while ensuring effective communication channels sensitive to language barriers. Challenges related to high population densities, access to communication means, and human behaviour highlight the need for dedicated emergency plans for tourists. These insights inform policymakers, emergency responders, and stakeholders in developing targeted interventions to enhance wildfire preparedness/response, ensuring the safety of tourists in cross-border regions.
Experimental large-scale pool fire with a fully engulfed tank
Authors: Rengel Borja , Dréan Virginie , Guillaume Bruno , Chiva Roman , Guillaume Eric
Published: November 2024

Tanks transporting hazardous materials must adhere to regulatory standards to ensure a high level of protection, thereby safeguarding individuals, communities, and the environment while minimizing economic losses. Specifically, tanks undergo testing in fully engulfed pool fires to evaluate their protective capabilities. This study provides an overview of the experimental setup involving a cylindrical tank exposed to a 21.6 m2 hydrocarbon pool fire in an open environment. The primary focus of the results is on the temperature distribution around the tank and the heat fluxes measured at various heights above the pool base.
Sensor based occupant monitoring
Authors: Gibbons Josh , Nilsson Daniel
Published: November 2024

There is an increasing need to know the presence, number and location of occupants in the built environment. This data can be used to optimise evacuation, inform rescue operations and collect occupancy data for fire safety design. It is possible to utilise sensors and systems already installed in buildings, such as demand-controlled ventilation systems, to monitor occupancy. The objective of this research is to develop a calculation model that uses data from demand-controlled ventilation systems to predict the number of occupants in a lecture theatre. The development process involved calibration experiments using CO2 gas release, as well as installation of new and modification of existing sensors. This paper presents the results of six experiments with one experiment in detail and compares the predicted number of occupants from the calculation model to the observed number of occupants in the lecture theatre. Results show positive and promising trends, with the model being able to estimate the number of occupants in the lecture theatre. Over the course of a lecture, the model predicted number of occupants with an error margin as small as 5%. An important finding from this research is that the accuracy of the prediction improves with the number of occupants in the room. At higher occupancy, changes in the CO2 concentration are larger and therefore easier to measure, resulting in the model being more responsive. The research shows the potential of using demand-controlled ventilation for prediction of number of occupants, with a strong rationale for further research.
Fire safety challenges with photovoltaics and Li-ion battery system installations in buildings
Authors: Sanfeliu Meliá Cristina , Stølen Reidar , Garberg Olsø Brynhild
Published: November 2024

The growing trend of using lithium-ion batteries as intermediate energy storage for renewable sources like solar panels is expected to increase in this decade, especially in buildings. Photovoltaic and Li-ion battery systems introduce certain fire risks which need to be considered before their implementation in new or existing buildings. Knowledge about the fire behaviour of both these systems, and how this may affect the building is crucial to reduce the consequences from a fire. The purpose of the work is to categorize the main fire safety challenges of PV and Li-ion battery installations for preventing fire and explosion hazardous scenarios in buildings. These are related to the increased risk of ignition, changed fire dynamics and increased fire spread risk, and to installations representing obstructions and hazards for firefighters. The research methodology consists of a combination of mixed methods: previous lessons learned in literature and experimental work and analysis of case studies. PV installations can cause ignition, promote fire spread and obstruct firefighting. A Li-ion battery installation can potentially increase the ignition risk, contribute to a rapid growth and spread of fire, and interfere firefighting and increase explosion hazards. The development of knowledge is important for the inclusion of new regulations and the modification of existing regulations in building codes nationally and internationally.
Assessing the Feasibility of Fire-pattern-based Data-driven Models for Pre-flashover Fire Origin Determination
Authors: Ni Shuna , David Unobe Ikwulono
Published: November 2024

This study evaluates data-driven methods for fire origin determination in pre-flashover fires based on interior fire pattern distribution. A proof-of-concept study was conducted by simulating six hundred compartment fire scenarios to generate data for model development. Heat exposure of interior surfaces was recorded to identify potential areas with fire patterns. Models such as Partial Least Squares Regression, Random Forest, and Support Vector Regression were tested, with Random Forest showing the best performance in locating fire origin. This study demonstrates the potential of data-driven models for identifying fire origins but highlights limitations in complex fire sites and scenarios.
The impacts of the economics and social status on the residential fire in Taiwan
Authors: Yung Lin Wang , Hung Chung Yu , Lung (Farian) Wu Chia
Published: November 2024

The research investigates whether the economics and social status affect the occurrence of the residential fire. Analysing the data from the National Fire Agency, Department of Household Registration, Department of Household Registration, Ministry of Health and Welfare, and National Statistics. The year range in which the data was obtained was from 2014 to 2022 due to the assessed availability. The results show that households with low incomes, people with disabilities, and full-time social workers directly influence the occurrence of fires, considering the size of the counties. If extracting the impact of the city size, the only significant impact is the aboriginal population.
The Role of Polarization for Bound States in Strong Fields
Authors: Walker B C , Jones E C , Andreula Z , Gale M R , Pham M , Wisely J
Published: November 2024

As atomic matter interacts with ultrastrong fields, the bound electrons are polarized and have ionization energies changed by Stark-shifting. The unprecedented range of laser intensities from 1015 W cm−2 to 1024 W cm−2 can take the interaction from the neutral atom to a bare nucleus. We have used an outer, single active electron approximation to calculate the polarization and Stark-shifted binding energy for ultraintense lasers interacting with highly charged ions at intensities from 1014 W cm−2 to 1022 W cm−2. The polarization of the bound state can result in a dipole moment and Stark shift that may be 0.1 e a0 and 50 Eh, respectively. At these high intensities, relativistic effects must also be considered. Across the intensity range of these studies, the magnetic field of the laser does not comparably affect the bound state of the atom; the impact of polarization and Stark shift exceed changes to the bound state wave function and binding energy from including relativity.
Vortex-Antivortex Pair Production in Perturbed Dipolar Bose-Einstein Condensate
Authors: Sabari S , Kishor Kumar R , Tomio Lauro
Published: November 2024

The dynamics of vortex-antivortex pair production with the associated critical velocities are investigated in perturbed dipolar Bose-Einstein condensates (BECs), by using a quasi-two-dimensional mean-field Gross-Pitaevskii (GP) model. By exploring the range of dipolar interaction strengths, it is also verified the regime in which turbulent behaviors can be observed. In the present contribution, we consider the emission of vortex and antivortex pairs in dipolar BECs produced by circularly moving blue detuned laser, simulated by a two-dimensional Gaussian obstacle. The critical velocities of the moving obstacle for vortex-antivortex nucleation, which emerge as regular pairs or cluster, are determined by numerical simulations, considering a BEC of dysprosium atoms with repulsive contact and dipolar interactions.
Optimizing States for Quantum-Enhanced Interferometry: Two Case Studies
Authors: Mishra Karunesh K. , Ataman Stefan
Published: November 2024

In this work we address the optimization of two important quantum states in terms of interferometric phase sensitivity, given a constraint on the total average number of input photons,

N
¯

We use the quantum Fisher information (QFI) as our main tool. We employ both the single- and two-parameter QFI in order to address detection schemes having, and respectively, not having access to an external phase reference. The first quantum state we consider is the coherent plus squeezed vacuum input and find the optimum coherent fraction that maximizes both the single- and two-parameter QFI. We also discuss detection schemes able to perform almost optimally. Finally, we consider the double squeezed vacuum input and determine the squeezed fraction between the inputs that maximizes the QFI. Similar to the previous input state, we also provide detection schemes able to perform optimally.
David, Gath, and the Politics of Identity
Authors: Leonard-Fleckman Mahri
Published: November 2024

Chapter 4 investigates scribal representations of Gath and its people in stories about David and Israel’s early monarchy to demonstrate that Gath is often depicted as a place and people who support and cooperate with David. This argument runs counter to the dominant stereotype of “the Philistines” as a fierce and powerful enemy of Israel, and counter to the common compositional claim that depictions of Gath become more negative over time. The chapter probes the diversity of scribal representations of Gath alongside theories of compositional development to expose the heterogeneity of scribal views on the David–Gath relationship, some more positive and some more negative, from biblical witnesses to Josephus’s first-century CE Jewish Antiquities. It also uses the book of Ruth and the positive presentation of a Moabite to demonstrate that textual representations of foreigners in general—not just the people of Gath—are situationally and temporally pliable.
Samson Mosaics
Authors: Leonard-Fleckman Mahri
Published: November 2024

In Chapter 6, Samson is the axis around which to explore textual development and history writing. The chapter argues that over time, Samson has functioned as a site of cultural memory and scribal discourse about the Shephelah relative to Israel and Judah’s histories. He is therefore a window into the continuous nature of historiography. The chapter probes Samson’s ongoing creation in composition and reception histories, from plausible mythological antecedents to a possible connection with Saul as early Israelite heroes, to his eventual placement in Judges and rewriting in Josephus’s Antiquities, continuing into modern reception. The chapter closes by returning to the archaeological remains from Tel Batash to interrogate the problematic use of biblical categories of identity in archaeological reconstructions and to argue that the composite artistry of the Samson cycle demonstrates a diversity of perspectives on his identity across space and time.
Gene cloning and characterization of N-carbamyl-l-glutamic acid amidohydrolase involved in ergothioneine utilization in Burkholderia sp. HME13
Authors: Muramatsu Hisashi , Yamada Masaaki , Maguchi Hiroki , Kato Shin-ichiro
Published: November 2024

Burkholderia sp. HME13 utilizes ergothioneine, a strong antioxidant, as the nitrogen source. We have previously shown that ergothionase, thiourocanate hydratase, 3-(5-oxo-2-thioxoimidazolidin-4-yl) propionic acid desulfhydrase, and hydantoin-5-propionic acid amidohydrolase may be involved in ergothioneine utilization in this strain. In this study, we identified the ertE gene in Burkholderia sp. HME13, which encodes a bivalent metal-dependent N-carbamyl-l-glutamic acid amidohydrolase (ErtE). ErtE showed maximum activity at 60 °C and pH 7.0 and was stable at temperatures up to 55 °C and pH 6.5-8.0. The Km and Vmax values of ErtE for N-carbamyl-l-glutamic acid were 0.74 m m and 140 U/mg, respectively. Ethylenediaminetetraacetic acid-treated ErtE showed no enzymatic activity, which was restored upon the addition of Co2+, Mn2+, Ni2+, and Fe2+. Expression analyses and enzymatic assays suggested that ErtE is involved in ergothioneine utilization in this strain. Finally, we propose a mechanism for ergothioneine utilization in Burkholderia sp. HME13.
How States Punch above Their Weight: Introducing Hybrid Actorness as Expanded Foreign Policy
Authors: McLarren Katharina , Stahl Bernhard
Published: November 2024

The interplay of states and transnational actors has found its way into Foreign Policy Analysis. At the same time, the call for new typologies of foreign policy actors has increased. We therefore develop a typological theory of expanded foreign policy and introduce a model of hybrid actorness that alludes to foreign policy actors with both state and transnational dimensions in their polity, politics, and policy. We assume that the transnational element is constitutive of such foreign policy actors. To theorize on such an expansion of foreign policy, we employ an abductive approach and revisit the polity, politics, and policy dimensions of foreign policy. We establish how these are expanded in five transnational sectors, namely state-religion, state-ideology, state-media, state-business, and state-diaspora. We then devise a typology of hybrid actorness by identifying different subtypes that range from latent to fully manifested hybrids. We argue that this model will help better grasp the evolving foreign policy phenomenon of the transnational in an increasingly globalized world.