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1.
Numerical heat transfer model for swelling intumescent coatings during heating
Andrea Lucherini, Juan P. Hidalgo, Jose L. Torero, Cristian Maluk, 2023, izvirni znanstveni članek

Povzetek: This research study presents a heat transfer model aimed at estimating the thermal and physical response of intumescent coatings. The numerical model is inspired by the outcomes of an experimental study focused on analysing the insulating effectiveness of a commercial intumescent coating for a range of heating conditions and initial coating thickness. The model solves the one-dimensional heat conduction problem using the finite-difference Crank-Nicolson method, and it assumes that the effectiveness of intumescent coatings is mainly dependent on their ability to develop swelled porous char. The coating swelling is implemented in the model by adopting an approach based on expanding the mesh representing the physical domain in proximity to the substrate-coating interface. The model described herein offers researchers and engineers a tool to estimate the heat transfer of swelling intumescent coatings (i.e. in-depth thermal gradient). Outcomes of the analysis shown herein demonstrate that the heat conduction within intumescent coatings is governed by the physical coating swelling and the thermal conditions at the coating-substrate interface. The numerical model shows that its accuracy is highly influenced by the coating thickness ahead of the reaction zone. Consequently, the coating swelling rate plays a key role, while the thermo-physical properties of the intumescent coating have a secondary effect. According to its assumptions, the model defines a quasi-steady-state thermal problem: it is more accurate for conditions close to steady-state (e.g. high heat fluxes), but it loses accuracy for cases characterised by transient phenomena (e.g. phases prior to the onset of swelling and low heat fluxes).
Ključne besede: intumescent coatings, heat transfer, numerical model, swelling, fire safety
Objavljeno v DiRROS: 08.01.2024; Ogledov: 139; Prenosov: 26
.pdf Celotno besedilo (1,21 MB)
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2.
Pathway toward sustainable winter road maintenance (case study)
Katja Malovrh Rebec, Janez Turk, 2023, samostojni znanstveni sestavek ali poglavje v monografski publikaciji

Povzetek: Life Cycle Assessment (LCA) method was applied to evaluate the environmental impacts of winter road maintenance managed by an innovative road-weather information system and the impacts of vehicles passing the road during the snowstorm event. A case study refers to 10-hour lasting snowstorm event, considering a specific road section and application of a road-weather information management system to help winter road maintenance agency optimizing activities (salt gritting and/or plowing). Reliable information on the timing of the beginning of the snowstorm event affects (1) the activities of winter road maintenance, (2) the mobility of all vehicles passing the road, and (3) the fuel consumption of the vehicles. Since activities are optimized in case of preventive operation of winter road maintenance, less salt is needed overall. The road remains free of snow cover in case of preventive winter road maintenance operation, meaning that passenger cars and trucks pass the road at normal speed, without undesirable acceleration and braking caused by wheels slipping if snow accumulates on the road. Fuel consumption of vehicles passing salted and snow-free road remains unchanged, while fuel consumption increases in case of snow cover. Reduction of environmental burdens in case of such optimized winter road maintenance operation, is shown in this case study. The overall results of the comparative LCA analysis showed that the use of the road-weather information system in road traffic allows for as much as 25% reduction of environmental footprints. In the scenario where the winter service does not use information system the winter service also uses 40% more salt, which is also related with additional environmental impacts.
Ključne besede: LCA, okoljski odtisi, cesta, snežne razmere, preventivno delovanje, promet, poraba goriva, varnost, LCA, environmental impacts, road, snow cover, preventive operation, traffic, fuel consumption, safety
Objavljeno v DiRROS: 11.12.2023; Ogledov: 143; Prenosov: 85
.pdf Celotno besedilo (19,01 MB)
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3.
Condition assessment of roadway bridges: from performance parameters to performance goals
Maria P. Limongelli, Eleni Chatzi, Andrej Anžlin, 2018, izvirni znanstveni članek

Povzetek: Deterioration of bridges due to ageing and higher demands, induced by increased traffic load, require the development of effective maintenance policies and intervention strategies. Such concern should be aimed at ensuring the required levels of safety, while optimally managing the limited economic resources. This approach requires a transversal advance; from the element level, through the system level, all the way to the network level. At the same time intervention prioritisation based on the importance of the system (bridge) inside the network (e.g. highway), or of the single structural element inside the bridge is dependent. The first step in bridge condition assessment is the verification of safety and reliability requirements that is carried out using the traditional prescriptive (deterministic) approach or the current performance-based (probabilistic) approach. A critical issue for efficient management of infrastructures lies in the available knowledge on condition and performance of bridge asset. This information is obtained using a collection of significant Performance Parameters at one or more of the three levels (element, system, and network). Traditional techniques for estimation of Performance Parameters rely on already established visual inspection. However, a more reliable description of the system performance is obtained through Non-Destructive Testing and Structural Health Monitoring. Condition assessment essentially pertains to the check of compliance with Performance Goals and requires the definition and computation of Performance Indicators. They are calculated directly from Performance Parameters or from physical models calibrated using the Performance Parameters collected on the structure. Paper overviews the steps to bridge condition assessment regarding safety and reliability.
Ključne besede: bridge, reliability, safety, condition assessment, performance goals, performance parameters
Objavljeno v DiRROS: 29.11.2023; Ogledov: 166; Prenosov: 92
.pdf Celotno besedilo (487,92 KB)
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4.
Cost-benefit analysis of fire protection in buildings : application of a present net value approach
Thomas Gernay, Shuna Ni, David Unobe, Andrea Lucherini, Ranjit Kumar Chaudhary, Ruben Van Coile, 2023, izvirni znanstveni članek

Povzetek: In fire safety engineering, cost–benefit analysis provides a systematic method to assess whether the projected benefits from a fire safety measure outweigh its costs. However, there remains a wide discrepancy between methods used in the field for cost–benefit analysis, as well as a lack of quantitative data on the costs and economic impact of fire protection in buildings. In a recent research project, a reference methodology was proposed based on Present Net Value evaluation and on a combination of specialized construction database, fire statistics, and numerical modeling for estimation of the cost components. This paper presents the application of the methodology to four case studies. The case studies allow describing the methodology, the collection of data, fire statistics, and loss estimation, as well as illustrating how the methodology can support decision-making when multiple alternatives are compared. Under the assumptions adopted for the single-family house and the residential timber building case studies, it is found that for every 1\$, invested in sprinklers, \$1.06 is saved. This benefit–cost ratio increases with increasing valuation of indirect losses and statistical value of life. Sensitivity analyses are provided to explore the robustness of the investment recommendations. The results of evaluations, adapted from the presented case studies with project-specific inputs, can support decision making for policy makers, insurance companies, and individual building owners.
Ključne besede: fire safety, cost-benefit analysis, fire protection, fire statistics, sprinklers, compartmentation
Objavljeno v DiRROS: 29.11.2023; Ogledov: 218; Prenosov: 30
.pdf Celotno besedilo (758,66 KB)
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5.
Defining the fire decay and the cooling phase of post-flashover compartment fires
Andrea Lucherini, Jose L. Torero, 2023, izvirni znanstveni članek

Povzetek: The current research study discusses and characterises the fire decay and cooling phase of post-flashover compartment fires, as they are often mixed up despite their important heat transfer differences. The two pha- ses are defined according to the fire heat release rate time-history. The fire decay represents the phase in which the fire heat release rate decreases from the ventilation- or fuel-limited steady-state value of the fully-developed phase to fire extinguishment. This phase is highly influenced by the fuel characteristics, ranging from fast decays for hydrocarbon and liquid fuels to slow decays for charring cellulosic fuels (wood). Once the fuel is consumed, the compartment volume enters the cooling phase, where the cooling in the gas-phase and solid-phase happens with significantly different modes and characteristic times. The thermal boundary conditions at the structural elements are then defined according to physical characteristics and dynamics within the compartment. The research study also underlines how the existing performance-based methodologies lack explicit definitions of the decay and cooling phases and the corresponding thermal boundary conditions for the design of fire-safe struc- tural elements under realistic fire conditions.
Ključne besede: razpadanje ognja, hlajenje, izgorevanje, naravna izpostavljenost ognju, dinamika požara, požari v oddelkih, požarno inženirstvo, učinkovitost, požarna varnost, fire decay, cooling, burnout, natural fire exposure, fire dynamics, compartment fires, structural fire engineering, performance-based, fire safety
Objavljeno v DiRROS: 13.11.2023; Ogledov: 246; Prenosov: 116
.pdf Celotno besedilo (4,91 MB)
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6.
A historical overview of experimental solid combustion research in microgravity
Wilson Ulises Rojas Alva, Grunde Jomaas, 2022, izvirni znanstveni članek

Povzetek: Studying solid combustion phenomena in microgravity environments can be complex, and this is furthered by many limitations and constraints in the available microgravity research platforms. Consequently, fire safety in spacecraft is also a complex subject. The main limitations found in the field are related to the microgravity quality, the duration of microgravity conditions, the rig capabilities in volume and size, time scales, length scales and the diagnostic systems, and these are therefore the focus in the current investigation. The laboratory capacity of ground-based platforms has remained somewhat stalled since 1990s, some drop towers have recently been upgraded to extend their performance. New space-based platforms have been or are being established and could extend the windows-of-opportunity to perform research. In addition, a discussion is provided on the implications of the fact that the phenomena studied in the experimental investigations and the type of material employed covers both programmatic and scientific needs. It is found that a handful of materials are most widely studied to quantify and characterise some of the phenomena, while some materials have been employed even in single experimental efforts. The current literature review provides a very comprehensive overview of previous experimental studies and the experimental methodologies utilised. Thus, this study can become an aid to planning for future studies.
Ključne besede: Microgravity, research platforms, solid combustion, fire safety, spacecraft
Objavljeno v DiRROS: 13.11.2023; Ogledov: 207; Prenosov: 47
.pdf Celotno besedilo (965,67 KB)
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7.
Flame spread behaviour of Polydimethylsiloxane (PDMS) membranes in 1 g and µg environments
Wilson Ulises Rojas Alva, Frederik Møller-Poulsen, Sze Lok Man, Cameron Creamer, David Hanna, Grunde Jomaas, 2022, izvirni znanstveni članek

Povzetek: Diffusion flame behaviour and silica ash (SiO2) production were experimentally studied for various Polydimethylsiloxane (PDMS) membrane thicknesses (0.125 mm to 1.0 mm) in normal gravity and during microgravity flight experiments. The flames were established on vertical samples (300 mm in length) and subjected to either opposed or concurrent forced flows (both laminar and turbulent), assimilating the NASA Test 1 that is in use for spacecraft material selection. The opposed flame spread rate was observed to be steady and could be estimated using classical theory. Under concurrent flow, the flame spread rate was only steady for very high forced flows. The opposed flame-spread rate ranged from 0.5 to 1.5 mm/s, while the concurrent case ranged between 0.1 and 12 mm/s. The transport of silica ash (SiO2) was found to affect the heat balance of the concurrent flame spread in a manner that resulted in unsteady flame spread. For opposed flame spread, on the other hand, the transport of silica ash showed to be irrelevant. The extinction behaviour for the concurrent flame spread was heavily dominated by the transport of silica-ash, while for opposed flames, extinction was due to kinetics (at high forced flows). In microgravity environments, the transport and deposition of silica ash is anticipated to dominate flame spread and near-limit as well. These results suggest that silica-based products might be less flammable in microgravity than other similar materials such as common thermoplastics (PP or PE) used as wire jackets.
Ključne besede: silicone burning, spacecraft fire safety, flame spread, near-limit, silica-ash
Objavljeno v DiRROS: 13.11.2023; Ogledov: 263; Prenosov: 51
.pdf Celotno besedilo (1,61 MB)
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8.
Cost-benefit analysis in fire safety engineering : state-of-the-art and reference methodology
Ruben Van Coile, Andrea Lucherini, Ranjit Kumar Chaudhary, Shuna Ni, David Unobe, Thomas Gernay, 2023, izvirni znanstveni članek

Povzetek: Cost-effectiveness is a key consideration within fire safety engineering. Currently, different approaches are being applied in literature. These approaches differ in how cost-effectiveness is evaluated, which costs are considered, and how the preferred design solution is defined. Recognizing this issue, the Fire Protection Research Foundation enrolled an international team of researchers, supported by a broad stakeholder panel, to develop a reference methodology. In this paper, this reference methodology for cost-benefit analysis in fire safety engineering is presented following an extensive literature review. The methodology clarifies the minimum requirements for assessing cost-effectiveness, and highlights that only a present net value evaluation can be used to compare design alternatives. Commonly used cost-benefit ratios should only be used when deciding on the effectiveness of a single package of fire safety measures. An illustrative case study demonstrates the application of the meth- odology and shows how designs based on cost-benefit ratios can be sub-optimal when evaluating multiple possible fire safety measures.
Ključne besede: cost-benefit analysis, fire safety, investment, maintenance, loss, statistics, reliability
Objavljeno v DiRROS: 23.10.2023; Ogledov: 264; Prenosov: 62
URL Povezava na datoteko
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9.
GoraNiNora : kontekstno-odvisno obveščanje za varen obisk gora
Domen Vilar, Veljko Pejović, Bojan Blažica, 2022, objavljeni znanstveni prispevek na konferenci

Ključne besede: mountain safety, notification system, mobile application, Android
Objavljeno v DiRROS: 01.02.2023; Ogledov: 443; Prenosov: 174
.pdf Celotno besedilo (1,70 MB)
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10.
Clinical and molecular practice of European thoracic pathology laboratories during the COVID-19 pandemic. The past and the near future
Paul Hofman, M. Ilié, E. Chamorey, P. Brest, R. Schiappa, V. Nakache, M. Antoine, M. Barberis, H. Begueret, F. Bibeau, Izidor Kern, 2020, izvirni znanstveni članek

Povzetek: Background: This study evaluated the consequences in Europe of the COVID-19 outbreak on pathology laboratories orientated toward the diagnosis of thoracic diseases. Materials and methods: A survey was sent to 71 pathology laboratories from 21 European countries. The questionnaire requested information concerning the organization of biosafety, the clinical and molecular pathology, the biobanking, the workload, the associated research into COVID-19, and the organization of education and training during the COVID- 19 crisis, from 15 March to 31 May 2020, compared with the same period in 2019. Results: Questionnaires were returned from 53/71 (75%) laboratories from 18 European countries. The biosafety procedures were heterogeneous. The workload in clinical and molecular pathology decreased dramatically by 31% (range, 3%-55%) and 26% (range, 7%-62%), respectively. According to the professional category, between 28% and 41% of the staff members were not present in the laboratories but did teleworking. A total of 70% of the laboratories developed virtual meetings for the training of residents and junior pathologists. During the period of study, none of the staff members with confirmed COVID-19 became infected as a result of handling samples. Conclusions: The COVID-19 pandemic has had a strong impact on most of the European pathology laboratories included in this study. Urgent implementation of several changes to the organization of most of these laboratories, notably to better harmonize biosafety procedures, was noted at the onset of the pandemic and maintained in the event of a new wave of infection occurring in Europe.
Ključne besede: covid-19, pathology, safety, lung neoplasms, biosafety, lung cancer
Objavljeno v DiRROS: 18.01.2021; Ogledov: 1270; Prenosov: 652
.pdf Celotno besedilo (665,44 KB)

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