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Dissertations / Theses on the topic 'Accidental Explosions'

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1

Vianna, Sávio Souza Venâncio. "Numerical simulation of accidental explosions in offshore production plant." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608535.

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2

Wong, C. W. "Numerical modelling of masonry panels subject to loading from gas explosions." Thesis, Middlesex University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337850.

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3

Camplese, Davide. "An experimental and numerical study on liquid fragmentation induced by an accidental industrial explosion." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2022.

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In a process involving hazardous liquids, if a chemical runaway reaction happens inside a tank, an explosion may occur and spreads the bulk liquid around the exploded vessel. Following the rapid ejection, the liquid will be fragmented into droplets both by the high-speed gas flow and blast propagation. The droplets dimension are directly related to the extent of the dispersion of toxic liquids and/or the combustion risk of a flammable aerosol thus produced. Therefore, it is of crucial relevance to study the phenomena involved in fragmentation, understanding the role played by hydrodynamic instabilities occurring at the liquid-high-pressure gas interface. Moreover, liquid fragmentation is supposed to be strongly dependent on the blast overpressure and the amount of liquid affected by the explosion. The present work analysed these aspects, simulating the impact of an explosion over a liquid layer using the shock tube facility. Firstly, a 1-D numerical model has been implemented to simulate the shock tube problem. Although the presence of viscosity effects was detected, a good match between model and experimental data was found in simulating the closed shock tube. Subsequently, the original shock tube set-up has been appropriately modified to accommodate the liquid on the top. Thus, the different overpressure behaviour in presence of water instead of a closed wall at the end of the tube was investigated. The comparison with the numerical model has allowed appreciating the water layer acts as a solid wall when reflecting the incident shock wave. Direct visualization of the fragmentation phenomenon and the instabilities has been achieved by using high-speed cameras. Several tests have been performed changing the mass of water involved and the pressure impulse impacting it, observing the correlation interacting between these parameters and the liquid acceleration throughout an image processing software.
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4

Leclerc, Éric. "Étude et modélisation de la phase d'escalade d'une explosion de vapeur." Université Joseph Fourier (Grenoble ; 1971-2015), 2000. http://www.theses.fr/2000GRE10210.

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Dans le cadre de l'interaction corium-eau, nous nous sommes interesses a la fragmentation d'origine thermique de gouttes de combustible. Les resultats experimentaux permettent d'identifier deux grandes familles de mecanismes de fragmentation conduisant a l'explosion de vapeur. La premiere decrit la fragmentation par piegeage de refrigerant au sein du combustible alors que la seconde decrit la deformation de la goutte chaude. Dans ces deux cas, les mecanismes sont lies a l'apparition d'instabilites de rayleigh taylor a l'interface film-refrigerant qui entrainent la mise en contact direct du corps chaud et du refrigerant. L'etude des mecanismes conduisant a la fragmentation par piegeage dans le corium des jets d'eau issus de l'instabilite de rayleigh taylor montrent que la penetration du liquide froid est trop faible pour obtenir une fragmentation de la goutte de combustible. Nous avons retenu un processus de fragmentation ou la production de fragments resulte d'une deformation de l'interface du corium. La formation de pics de combustible est due a des pressurisations locales sur la surface du combustible, consecutives a l'impact des jets de refrigerant et de leur vaporisation. La modelisation fait apparaitre un parametre tres important, la densite de nucleation n qui determine la quantite de vapeur, formee lors des echanges de chaleur induits par le contact liquide liquide. Notre analyse montre que c'est la pression ambiante lors de la nucleation qui gouverne ce parametre. En restant coherent avec les ordres de grandeurs connus, le choix empirique d'une valeur de n lors de chaque contact liquide liquide, permet de retrouver analytiquement les resultats experimentaux d'explosion de gouttes par le mecanisme de fragmentation thermique propose.
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5

Clearwater, David A. ""Where were you when...?" : the interaction of the personal and the historical in the Challenger explosion." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0003/MQ43848.pdf.

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6

Nguyen, Quoc Bao. "Fiabilité des installations industrielles sous impact de fragments de structures - Effet domino." Phd thesis, Université Paris-Est, 2009. http://tel.archives-ouvertes.fr/tel-00551266.

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La plupart des sites industriels abritent des équipements et des réservoirs sous pression. Pour des raisons diverses (suppression, impact mécanique, surchauffe ou autre), ils peuvent être endommagés et même éclater. Cette explosion peut engendrer de nombreux projectiles. Au cours de leur vol, ces derniers peuvent impacter d'autres équipements, tels que des réservoirs sous pression ou d'autres installations sensibles (poste de commande, par exemple). Si une des cibles impactées subit une ruine mécanique, elle peut exploser et générer une nouvelle série de projectiles. Ces projectiles menacent, à leur tour, d'autres installations et ainsi de suite. Ce type d'enchaînement accidentel catastrophique est connu sous le nom d'effet domino ou de suraccident. Dans ce document, l'effet domino pouvant se produire sur des sites industriels est analysé au travers des projections produites par l'accident initial. Une approche probabiliste globale est ainsi développée dans laquelle le calcul de la probabilité d'occurrence du phénomène requiert le passage par quatre étapes : - Analyse des termes sources : les projectiles générés par l'explosion d'un réservoir ont différentes caractéristiques, à savoir le nombre de projectiles, la forme, la masse, la vitesse de départ et les angles de départ. Toutes ces grandeurs sont modélisées par des variables aléatoires. A l'aide du principe du maximum d'entropie et des données existantes, des distributions probabilistes sont développées pour toutes ces variables. On se limite, cependant, au cas de l'explosion d'un réservoir cylindrique ou sphérique. - Analyse de l'impact ou analyse du mouvement : la trajectoire d'un projectile (ou fragment de structure), en fonction de ses caractéristiques de départ, est décrite par une combinaison des effets d'inertie, de gravitation et d'aérodynamique. Une approche simplifiée faisant l'hypothèse de constance des coefficients aérodynamiques permet d'identifier analytiquement la trajectoire du projectile tandis qu'une solution numérique est obtenue par une approche complète où toutes les valeurs de ces coefficients sont prises en compte.Les mouvements de translation et de rotation sont également étudiés. A l'aide de l'analyse complète et des conditions d'impact, la probabilité d'impact est déterminée. L'étude est restreinte à des projectiles en forme de fond de réservoir, fond oblong de réservoir et plaque. Les formes des cibles de l'étude sont restreintes au cas ellipsoïdal, cylindrique et cubique. - Analyse de l'état des cibles impactées : dans un premier temps, des modèles simplifiés d'impact sont utilisés afin d'étudier l'interaction mécanique entre les projectiles et les réservoirs impactés. Un modèle mécanique complet comprenant une loi de comportement élasto-plastique et un modèle de rupture est également proposé. Ce modèle est ensuite implémenté dans un code de calcul sans maillage de type SPH, i.e. Smoothed Particle Hydrodynamics. Afin d'estimer la probabilité de rupture des réservoirs impactés, les modèles simplifiés sont mis en œuvre, ce qui permet de réduire le coût de calcul. - Occurrence du sur-accident : selon l'état mécanique résiduel de la cible et son état physique (conditions thermodynamiques, niveau de remplissage, etc.), l'impact de projectiles peut conduire à la poursuite du pnénomène. Ce dernier point n'est pas traité dans le document présenté
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7

Díaz, Alonso Fernando. "Análisis de consecuencias y Zonas de Planificación para explosiones industriales accidentales (en el ámbito de las Directivas Seveso)." Doctoral thesis, Universidad de Murcia, 2006. http://hdl.handle.net/10803/10935.

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Este trabajo aborda el estudio de las explosiones industriales accidentales, realizando una revisión bibliográfica en este campo y recopilando los principales modelos de cálculo de las magnitudes peligrosas de las explosiones (onda de presión y fragmentos). Se proponen mejoras a los modelos existentes y se desarrolla una nueva herramienta de análisis de consecuencias, denominada curvas características de las explosiones, que relaciona directamente sobrepresión, impulso y distancia, permitiendo establecer el alcance de los daños.Se analizan también los valores límite de la legislación española para establecer las Zonas de Planificación en emergencias, concluyendo que no ofrecen un adecuado nivel de seguridad, realizándose una nueva propuesta basada en criterios de daño y en el análisis de accidentes reales.Por último, se ha elaborado un programa informático (ZEUS) que utiliza los modelos estudiados para calcular las Zonas de Planificación propuestas y los daños sobre seres humanos y edificios producidos por las explosiones.<br>This work undertakes the study of accidental industrial explosions. A bibliographical review is made in this field, taking and improving the main models for the calculation of dangerous magnitudes for explosions (pressure wave and fragments). In addition, a new tool for consequence analysis is developed, referred to as characteristics curves for explosions, which relate directly overpressure, impulse and distance, allowing the calculation of damage caused by industrial explosions. Threshold values published by the Spanish legislation for the establishment of Emergency Planning Zones are also analyzed, concluding that they do not offer a suitable safety level. Thus, new values are proposed taking into account damage criteria and real accident analysis. Finally, a computer program (ZEUS), that uses the models studied in this Thesis, has been elaborated to calculate Planning Zones, as well as damages produced by explosions on humans and buildings.
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8

Gilbert, Stephen Michael. "A model for the effects of a condensed phase explosion in a built-up area." Thesis, Loughborough University, 1994. https://dspace.lboro.ac.uk/2134/11124.

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A model has been developed to assess the hazard presented by a condensed phase explosion in a built-up area. The principal application of this model is as an aid to quantitative risk assessment (QRA) of operations involving the transport of high explosive substances' and articles by road or by rail. The methodology employed is to utilise a consequence model in conjunction with a scenario model. The consequence model is used to establish as a function of distance the intensities of the various explosion phenomena and then to estimate, again as a function of distance, the injuries that are likely to result. This yields probabilities that persons will become casualties of the accident, given that people are exposed to the hazard. This effectively determines the level of individual risk as a function of distance. The scenario model is employed to define the location of the population in terms of its vulnerability (exposure) at the time of the explosion. This enables the total number of casualties to be estimated and is effectively a measure of societal risk. Elements of the consequence model include submodels for housing damage and. indoor injury; window breakage and injury from flying glass; air blast and injury by lung damage, eardrum rupture and impact as a result of bodily displacement; fireball and bum injury; generation, flight and wounding power of primary fragments; other explosion ejecta; and falling building debris (glass and masonry). The overall model has been implemented as a computer program, 'EXMOD'. The primary fragmentation submodel has been used as the basis of another, 'EXFRAG'. Many of the results presented in this thesis have been obtained with the aid of these computer programs.
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9

Ranc, Isabelle. "Modélisation de la fragmentation fine lors de la phase de déclenchement d'une explosion de vapeur." Université Joseph Fourier (Grenoble ; 1971-2015), 1997. http://www.theses.fr/1997GRE10106.

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Ce travail est motive par les etudes de surete relatives aux accidents graves des reacteurs a eau pressurisee, qui envisagent la fusion du coeur. Dans ce cadre, on etudie une des phases de l'explosion de vapeur ou interaction corium-eau, c'est-a-dire la vaporisation violente du refrigerant lors d'un choc thermique entre un liquide tres chaud et un liquide froid. L'objet de l'etude est la phase de declenchement de l'interaction, pendant laquelle une goutte de combustible, de l'ordre du centimetre, initialement entouree d'un film de vapeur, se fragmente en debris de l'ordre de la centaine de micrometres. Le modele decrit le cycle de croissance et de collapse d'une bulle de vapeur autour de la goutte et sa fragmentation. Les differentes etapes du scenario ont ete modelisees. Les points principaux sont : -la destabilisation du film ou de la bulle par des instabilites de rayleigh-taylor conduisant des contacts directs entre le corps chaud et le refrigerant, -les mecanismes de fragmentation obtenus a la suite de ces contacts. En particulier, pour le mecanisme d'emprisonnement de refrigerant a l'interieur de la goutte, le comportement thermique du refrigerant a ete decrit par une evaporation brutale lorsque la limite de surchauffe est atteinte, -le transfert de chaleur transitoire entre les fragments et le refrigerant et la production de vapeur importante. Sur ce dernier point, a l'issue d'une analyse bibliographique, le refroidissement des fragments a ete decrit par un transfert de chaleur transitoire, mettant en jeu la physique de l'ebullition par nucleation spontanee. Les resultats du modele sont compares de facon satisfaisante aux resultats experimentaux.
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10

Robbe, Marie-France. "Modélisation en dynamique rapide d'accidents dans le circuit primaire des réacteurs à eau pressurisée." Châtenay-Malabry, Ecole centrale de Paris, 2003. http://www.theses.fr/2003ECAP0929.

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Deux types d'accidents, pouvant se produire dans le circuit primaire d'un Réacteur nucléaire à Eau Pressurisée (REP) et impliquant des phénomènes de dynamique rapide, sont analysés. L'Accident de Perte de Réfrigérant Primaire (APRP) est l'accident de dimensionnement des REP actuels. Il s'agit d'une brèche de grande dimension sur une tuyauterie du circuit primaire. Une onde de décompression se propage à travers le circuit. Les différences de pression entre les différents volumes du réacteur induisent des efforts mécaniques importants sur les structures de la cuve et peuvent détériorer le cœur du réacteur. Le circuit primaire commence à se vider dès l'ouverture de la brèche. La pression décroît brutalement, entraînant une vaporisation massive. Deux simulations thermo-hydrauliques de la phase de décompression d'un APRP avec le code de calcul Europlexus sont présentées. Le circuit primaire est décrit par un modèle filaire, incluant les perturbations hydrauliques du circuit. Les principales différences entre les deux calculs concernent le type de réacteur, la localisation et le modèle de la brèche, et l'initialisation du calcul accidentel. L'explosion de vapeur est un accident hypothétique grave pouvant se produire à la suite de la fusion du cœur du réacteur. La partie fondue du cœur (dénommée corium) tombe dans le fond de la cuve. L'interaction du corium chaud avec l'eau froide restant au fond de la cuve induit une vaporisation massive et brutale de l'eau. Une onde de choc se propage dans la cuve, ce qui peut endommager sérieusement les structures avoisinantes ou percer localement la cuve. Cette thèse présente une synthèse d'études paramétriques d'une explosion dans le fond de cuve d'un REP avec le code Europlexus, le chaînage du code de thermo-hydraulique Mc3d dédié à la phase de prémélange avec le code Europlexus permettant le calcul de l'explosion, et un benchmark entre les codes Cigalon et Europlexus sur la maquette Vulcano.
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11

Vujic, Zoran [Verfasser]. "Improvement and verification of steam explosion models and codes for application to accident scenarios in light water reactors / vorgelegt von Zoran Vujic." Stuttgart : IKE, 2008. http://d-nb.info/997049855/34.

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12

Wei, Linkai. "Development of a new steam explosion model for the MC3D software." Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0097.

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L'explosion de vapeur est l'un des phénomènes les plus critiques et complexes qui peuvent se produire lors d'un accident grave dans une centrale nucléaire. Le code MC3D est reconnu comme une référence pour l'évaluation de ce phénomène. Ce phénomène explosif est analogue à une détonation. L'explosion est due à la fragmentation du combustible fondu, au passage de l'onde de choc et à la libération très rapide de l'énergie associée. Cependant, les mécanismes précis du processus de pressurisation sont très incertains et ont fait l'objet de travaux réalisés dans le cadre du programme RSNR-ICE (2014-2023), qui ont permis de mieux comprendre la phénoménologie générale et de valider le principe général de MC3D, basé sur un principe d'ébullition directe autour de la surface des fragments de corium via un mécanisme d'ébullition en film. Or, il apparaît que les processus de fragmentation semblent, dans certaines conditions, se réaliser sans une dispersion significative des fragments dans l'eau, ce qui est contraire à ce que présuppose le modèle MC3D actuel. L'objectif de la thèse est de proposer une modélisation améliorée de l'explosion pour MC3D, combinant le principe actuel d'ébullition directe et d'interaction combustible-refroidissement localisée dans un petit volume autour des gouttes de corium et des fragments. Après une bibliographie extensive du phénomène d'explosion de vapeur, une analyse détaillée du comportement du modèle MC3D actuel est effectuée, en utilisant un cas-test simple et idéal. Malgré la simplicité de l'ensemble de données, l'analyse peut être directement appliquée aux expériences à géométrie unidimensionnelle telles que KROTOS. Le rôle crucial du vide initial et du vide créé est mis en évidence ; il suggère également les premiers contours d'un nouveau modèle. Le logiciel Basilisk a ensuite été utilisé pour effectuer des simulations DNS afin d'obtenir des détails sur les transferts thermiques de fragmentation et d'association. Une analyse complète des régimes de fragmentation, des statistiques incluant le diamètre moyen de Sauter et la fonction de densité de probabilité de la masse et de la surface des fragments, du nombre de Nusselt transitoire et du coefficient de traînée a été menée. Dans le même temps, les résultats du même cas d'essai utilisant MC3D sont comparés à ceux de Basilisk, ce qui met en évidence la nécessité de modifier le modèle MC3D. Enfin, les grandes lignes d'un nouveau modèle proposé sont présentées et discutées. Celles qui ont pu être validées directement à partir des résultats du DNS ont été implémentées dans la version actuelle de MC3D. Il s'agit en particulier de l'introduction d'une Micro-Interaction de Non-Equilibre (NEMI), Les autres propositions concernant le comportement du vide pourront être implémentées dans la future version (V4) du code<br>The steam explosion is one of the most critical and complex phenomena that may occur during severe accident in a Nuclear Power Plant. The MC3D computer code is recognized as reference for the evaluation of this phenomenon. This explosive phenomenon is analogous to a detonation. The explosion is due to the fragmentation of the molten fuel, the passage of the shock wave and the very fast release of the associated energy. However, the precise mechanisms of the process of pressurization are very uncertain and have been the subject of works carried out under the program RSNR-ICE (2014-2023), which led to an increased understanding of general phenomenology and validated the general principle of MC3D, based on a principle of direct boiling around the surface of the corium fragments via a film boiling mechanism. However, it appears that the fragmentation processes seem, under certain conditions, to be achieved without a significant dispersion of the fragments in the water, which is contrary to what presupposes the current MC3D model. The aim of the thesis is to propose an improved modeling of the explosion for MC3D, combining the current principle of direct boiling and fuel-coolant interaction localized in a small volume around the corium drops and fragments. Following an extensive bibliography of the steam explosion phenomenon, a detailed analysis of the behavior of the current MC3D model is performed, using a simple and ideal test-case. Despite the simplicity of the data set, the analysis can be directly applied to experiments with one-dimensional geometry such as KROTOS. The crucial role of initial and created void is highlighted; It also suggests the first outlines of a new model. The Basilisk software was then used to perform DNS simulations to get details of fragmentation and association heat transfers. Comprehensive analysis about fragmentation regimes, statistics including Sauter Mean Diameter and Probability Density Function of fragment mass/area, the transient Nusselt number and drag coefficient were conducted. At the same time, results for the same test-case using MC3D are compared with that of Basilisk, highlighting the need of modification of MC3D model. Finally, the main lines of a proposed new model are presented and discussed. Those that could be directly validated from the DNS results were implemented in the current MC3D version. This concerns in particular the introduction of a Non-Equilibrium Micro-Interaction (NEMI), The other proposals concerning the behavior of the void may be implemented in the future version (V4) of the code
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13

Juocevičius, Virmantas. "Ypatingųjų poveikių statiniams sukeliamos rizikos vertinimo metodas." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20111228_165051-40824.

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Disertacijoje aprašomas metodas, sukurtas vertinti ypatingųjų poveikių statiniams keliamą riziką. Darbe pateikti trys šio metodo taikymo pavyzdžiai. Disertaciją sudaro įvadas, penki skyriai, išvados, literatūros šaltiniai, autoriaus publikacijų sąrašas ir penki priedai. Pirmajame skyriuje apžvelgiama mokslinė literatūra, kurioje tiriami rizikos vertinimo metodai ir aptariama jų taikymo konstrukcijoms skaičiuoti galimybė. Pateikiama trumpa ypatingųjų poveikių klasifikacija bei konstrukcijų, kurias jie gali paveikti, pažeidžiamumo modeliavimas. Antrajame skyriuje aprašomas metodas, sukurtas ypatingųju poveikių keliamų konstrukcijų pažaidų tikimybėms vertinti. Metodas derina statybinių konstrukcijų patikimumo teorijos ir Bajeso statistinės teorijos priemones. Jis gali būti taikomas tiek projektuojant konstrukcijas, tiek vertinant pramoninių objektų riziką. Trečiajame skyriuje aprašoma, kaip taikyti siūlomą metodą vertinant medinėms konstrukcijoms keliamą gaisro riziką. Ta rizika išreiškiama gaisro pažeistos konstrukcijos suirimo tikimybe, kuri yra vertinama apriorine ir aposteriorine tankio funkcijomis, skaiciuojamomis Bajeso statistinės teorijos priemonėmis. Šiame skyriuje nagrinėjama medinė gaisro veikiama pramoninio pastato stogo konstrukcijos sija. Gaisro poveikis modeliuojamas maža statistine gaisro charakteristikų imtimi. Ketvirtajame skyriuje pateiktas siūlomo metodo taikymas projektuojant sprogimo veikiamą apsauginį barjerą. Atsižvelgiama i barjero elementų mechaninio... [toliau žr. visą tekstą]<br>The dissertation presents a method developed for assessing the risk to constructed facilities posed by accidental actions. The proposed method is applied to the analysis of structures subjected to accidental actions induced by fire, explosion and extreme wind. The dissertation consists of introduction, five chapters, conclusions, lists of references and papers published by the author of the dissertation, as well as five annexes. Chapter 1 presents a review of published work on the assessment of risk to structures and non-structural property posed by accidental actions. The review covers general aspects of risk assessment and application of risk analysis tools to the analysis and design of structures. The core of the review is an application of Bayesian methods, which prevail in the field of risk assessment, to a risk-based structural analysis. Chapter 2 proposes a method developed for the assessment of damage to structures from accidental actions. This method combines structural analysis with Bayesian handling of information related to accidental actions and response of structures to these actions. The method allows to estimate probabilities of the damage to structures caused by accidental actions. Chapter 3 deals with an application of the proposed method to the estimation of fire risk to structures. It is shown how to apply this method to the estimation of failure probability of a timber beam damaged by fire in an industrial building. This chapter shows how to handle... [to full text]
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14

Mungan, Arda Meral. "Risk Assessment For A Denim Manufacturing Plant In Turkey." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609700/index.pdf.

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A risk assessment study is conducted in a denim manufacturing plant in Turkey. The study is carried out within the framework of a project on adopting the Integrated Pollution Prevention and Control (IPPC) Directive of the European Union. The scope of the assessment is fire or explosion risk with regards to hazardous chemicals present in the plant. The receptor of the study is defined as &ldquo<br>people&rdquo<br>which include the employees in the plant, employees of nearby plants and people in residential around the mill. A semi-quantitative risk assessment is carried out using checklist, a risk matrix and risk evaluation forms. The highest risks in the plant are identified as dust explosions, natural gas jet fires, natural gas explosions. Also, it is identified that due to several causes, in case of a fire or explosion the scale of an accident may enlarge instantaneously. The main warehouse is determined to carry the highest risk value in the plant. Mathematical modelling studies are conducted to calculate the hazard radius for dust explosions and natural gas fire and explosion. According to the results of mathematical modelling, the highest consequences could lead to destruction of buildings or severe injuries/fatalities of people within large hazard radius up to 700 m. The risk present at the manufacturing mill is communicated to the facility management throughout the study. Several suggestions are proposed to the facility management and some of them are already implemented.
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15

Thakre, Sachin. "On Fuel Coolant Interactions and Debris Coolability in Light Water Reactors." Doctoral thesis, KTH, Kärnkraftssäkerhet, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-166261.

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During the case of a hypothetical severe accident in a light water reactor, core damage may occur and molten fuel may interact with water resulting in explosive interactions. A Fuel-Coolant Interactions (FCI) consists of many complex phenomena whose characteristics determine the energetics of the interactions. The fuel melt initially undergoes fragmentation after contact with the coolant which subsequently increases the melt surface area exposed to coolant and causes rapid heat transfer. A substantial amount of research has been done to understand the phenomenology of FCI, still there are gaps to be filled in terms of the uncertainties in describing the processes such as breakup/fragmentation of melt and droplets. The objective of the present work is to substantiate the understanding in the premixing phase of the FCI process by studying the deformation/pre-fragmentation of melt droplets and also the mechanism of melt jet breakup. The focus of the work is to study the effect of various influential parameters during the premixing phase that determine the intensity of the energetics in terms of steam explosion. The study is based on numerical analysis starting from smaller scale and going to the large scale FCI. Efforts are also taken to evaluate the uncertainties in estimating the steam explosion loads on the reactor scale. The fragmented core is expected to form a porous debris bed. A part of the present work also deals with experimental investigations on the coolability of prototypical debris bed. Initially, the phenomenology of FCI and debris bed coolability is introduced. A review of the state of the art based on previous experimental and theoretical developments is also presented. The study starts with numerical investigation of molten droplet hydrodynamics in a water pool, carried out using the Volume Of Fluid (VOF) method in the CFD code ANSYS FLUENT. This fundamental study is related to single droplets in a preconditioning phase, i.e. deformation/pre-fragmentation prior to steam explosion. The droplet deformation is studied extensively also including the effect of the pressure pulse on its deformation behavior. The effect of material physical properties such as density, surface tension and viscosity are investigated. The work is then extended to 3D analysis as a part of high fidelity simulations, in order to overcome the possible limitations of 2D simulations. The investigation on FCI processes is then continued to the analysis on melt jet fragmentation in a water pool, since this is the crucial phenomenon which creates the melt-coolant pre-mixture, an initial condition for steam explosion. The calculations are carried out assuming non-boiling conditions and the properties of Wood’s metal. The jet fragmentation and breakup pattern are carefully observed at various Weber numbers. Moreover, the effect of physical and material properties such as diameter, velocity, density, surface tension and viscosity on jet breakup length, are investigated. After the fundamental studies, the work was extended to reactor scale FCI energetics. It is mainly oriented on the evaluation of uncertainties in estimating the explosion impact loads on the surrounding structures. The uncertainties include the influential parameters in the FCI process and also the code uncertainties in calculations. The FCI code MC3D is used for the simulations and the PIE (propagation of input errors) method is used for the uncertainty analysis. The last part of the work is about experimental investigations of debris coolability carried out using the POMECO-HT facility at KTH. The focus is on the determination of the effect of the bed’s prototypical characteristics on its coolability, in terms of inhomogeneity with heap like (triangular shape) bed and the radial stratified bed, and also the effect of its multi-dimensionality. For this purpose, four particle beds were constructed: two homogeneous, one with radial stratification and one with triangular shape, respectively. The effectiveness of coolability-enhanced measures such as bottom injection of water and a downcomer (used for natural circulation driven coolability, NCDC) was also investigated. The final chapter includes the summary of the whole work.<br>Under ett svårt haveri i en kärnkraftsreaktor kan en härdsmälta bildas och smältan växelverka på ett explosivt sätt med kylvattnet. En sådan FCI (Fuel-Coolant-Interaction) inbegriper flera fysikaliska processer vilkas förlopp bestämmer hur stor den frigjorda energin blir. Vid kontakt med vattnet fragmenteras först härdsmältan vilket i sin tur leder till att en större yta exponeras för kylvattnet och att värmeöverföringen från smältan snabbt ökar. Mycket forskning har ägnats åt att förstå vad som sker under en FCI men det finns fortfarande luckor att fylla vad beträffar t ex osäkerheter i beskrivningen av fragmentering av såväl smälta som enskilda droppar av smält material. Syftet med detta arbete är främst att underbygga en bättre förståelse av den inledande delen av en FCI genom att studera dels hur enskilda droppar av smält material deformeras och splittras och dels hur en stråle av smält material fragmenteras. Vi studerar särskilt vilka parametrar som mest påverkar den energi som frigörs vid ångexplosionen. Problemet studeras med numerisk analys med början i liten skala och sedan i full skala. Vi söker också uppskatta de laster som explosionen utsätter reaktorns komponenter för. En annan viktig fråga gäller kylbarheten hos den slaggansamling som bildas under reaktorhärden efter en FCI. Slagghögen förväntas ha en porös struktur och en del av avhandlingen redogör för experimentella försök som genomförts för att utvärdera kylbarheten i olika prototypiska slaggformationer. I avhandlingens inledning beskrivs de fysikaliska processerna under en FCI och kylningen av en slaggansamling. Det aktuella kunskapsläget på dessa områden presenteras också utgående från tidigare experimentella och teoretiska studier. Studierna i avhandlingen inleds med numerisk analys av hydrodynamiken för en enskild droppe smälta i en vattentank där VOF-metoden i CFD-programmet ANSYS FLUENT används. Denna grundläggande studie rör en enskild droppe under förstadiet till fragmentering och ångexplosion då droppen deformeras alltmer. Deformationen studeras ingående också med hänsyn tagen till inverkan av en tryckpuls. Inverkan av olika egenskaper hos materialet, som densitet, ytspänning och viskositet studeras också. Arbetet utvidgas sedan till en beskrivning i 3D för att undvika de begränsningar som finns i en 2D-simulering. Studierna av FCI utvidgas sedan till en analys av fragmentering av en stråle smälta i vatten. Detta är en kritisk del av förloppet då smälta och vatten blandas för att ge utgångstillståndet för ångexplosionen. Beräkningarna genomförs under antagande att kokning inte sker och med materialegenskaper som för Wood´s metall. Mönstret för fragmentering och uppsplittring studeras ingående för olika Weber-tal. Dessutom studeras effekten på strålens uppsplittringslängd av parametrar som diameter och hastighet för strålen samt densitet, ytspänning och viskositet hos materialet. Efter dessa grundläggande studier utvidgas arbetet till FCI-energier i reaktorskala. Här ligger tonvikten på utvärdering av osäkerheter i bestämningen av den inverkan explosionen har på omgivande konstruktioner och komponenter. Osäkerheterna inkluderar eventuell bristande noggrannhet hos såväl de viktiga parametrarna i FCI-processen som i själva beräkningarna. Den sista delen av arbetet handlar om experimentella undersökningar av slaggformationens kylbarhet som genomförts i uppställningen POMECO-HT vid avdelningen för kärnkraftsäkerhet på KTH. Vi vill bestämma effekten av formationens prototypiska egenskaper på kylbarheten. För detta ändamål konstruerades fyra olika formationer: två homogena, en med radiell variation i partikelstorlek och en med triangulär variation. Vi undersökte också hur förbättrad kylning kan uppnås genom att tillföra kylvatten underifrån respektive via ett fallrör (kylning genom naturlig cirkulation). I det avslutande kapitlet ges en sammanfattning av hela arbetet.<br><p>QC 20150507</p>
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Hajný, Vít. "Výběr zdrojů rizik a jejich hodnocení při skladování výbušnin." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-255788.

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The Master´s thesis concerns with the choice of sources of risks and their evaluation with storage of explosives. It is divided into four parts. The first two parts are research ones and they deal with accesses to the choice of sources of risks with storage of explosives and statutory requirements for explosives, their storage, manipulation and transport and then with the buildings, which the explosives are stored in. In the next part the accesses to selection and evaluation of sources of risks in real storage units are chosen and compared. In the final part there is the chosen methodology used in case studies.
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17

DANZI, ENRICO. "Development of Speditive Explosibility Test (SET): a statistical reliable method for combustible dust explosibility investigation." Doctoral thesis, Politecnico di Torino, 2016. http://hdl.handle.net/11583/2650519.

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The present work of thesis investigate the explosibility sensitivity and behavior of combustible solid materials, in the form of dusts. The first phase of the work has focused on the ignition sensitivity of combustible dusts, both in form of clouds than deposed as layers. Standard test methods has been used to assess ignition parameter of the samples, i.e. UNI EN 50821: 1999. MITC and MITL were measured for pure combustible dusts and for mixtures of different dusts. In particular mixtures of combustible and inert dusts were analyzed. The experimental results underlined the increase of the ignition temperature (both in clouds than in layers) as the weight content of inert material increase. Extinguishing powders with chemical heat depletion effect had demonstrated to be more effective in increasing the ignition temperature with respect to inert acting with physical inertia mechanism. MITC of two combustible dusts mixture have been analyzed and results have shown the poor accuracy of the standard procedure in defining the ignition temperature, particularly when there is little difference between ignition temperatures of the pure materials. The author has attempted to reduce this lack of accuracy, inadequate when a high level of details is required (like for scientific purposes) in ignition measurements through different statistical analysis of experimental data. This study has generated a statistical approach to the investigation of dust ignition temperature with the definition of the SIT (Statistical Ignition Temperature) and the definition of a Probability Escalation Interval (PEI); within PEI ignition probability of dusts vary between 0 and 1 with respect to temperature. The results obtained show that standard methods adopted worldwide could fail in determine the MITC of dusts and bring a new, more accurate methodology as a contribution on the definition of ignition concept of dusts. The statistical study could also apply to ignition criteria of the explosibility test proposed here, in order to give to SET procedures and results a more reliable statistical value. The Speditive Explosibility Test has the form of a screening procedures for defining explosibility of dust samples, with the aim of avoiding time and cost-consuming standard procedures. The test consist in different procedures derived from standards (mainly UNI EN 50821 and UNI EN 13821) which ignition conditions are modified to be “as worst as possible”, in order to avoid marginally explosive dusts to be classified as non explosible. Tests were performed on different dusts samples (by chemical composition, nature, PSD) and results were validated through explosion test in the 20 L Siwek-sphere. The test classification shows, for the majority of the samples collected, good agreement with literature standard explosibility tests. The SET could be assumed as standard test for the explosibility determination of a dust. A second experimental campaign was performed on non-traditional dusts coming from textile industries. All samples PSD was analyzed and 15 over 100 total were submitted to the SET with the aim to obtain more data on explosive behavior of those type of dusts.
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Sauvan, Pierre-Emmanuel. "Etude des phénomènes physiques associés à la propagation d'ondes consécutives à une explosion et leur interaction avec des structures, dans un environnement complexe." Phd thesis, Université d'Orléans, 2012. http://tel.archives-ouvertes.fr/tel-00802429.

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Les travaux présentés dans ce mémoire de thèse s'inscrivent dans le cadre des études liées aux dégâts sur les structures et les blessures subies par les personnes à la suite d'explosions de charges explosives en milieu confiné et semi-confiné. Afin de mener cette étude, des expériences sont réalisées à petite échelle en laboratoire et sont complétées par des simulations numériques. Les ondes de choc sont obtenues grâce à la détonation d'une charge explosive gazeuse composée de propane-oxygène en proportion stoechiométrique. L'étude consiste donc à réaliser des expériences à petite échelle en laboratoire afin d'apprécier les champs de pression obtenus à la suite de la détonation d'une charge explosive au sein de deux configurations différentes. La première représente un atelier pyrotechnique et la seconde met en jeu un entrepôt de stockage de bouteilles de gaz. Les résultats expérimentaux sont ensuite confrontés à des résultats obtenus par simulations numériques réalisées grâce au logiciel AUTODYN. En complément de ces deux configuration principales, une étude est menée sur l'identification des pics de surpressions réfléchis grâce à une approche expérimentale appelée paroi par paroi. Une étude est également menée sur la détermination d'une équivalence massique entre le TNT et le mélange gazeux utilisé pour les expériences.
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Guerra, André. "Modeling Mild Thermal Cracking of Heavy Crude Oil and Bitumen with VLE Calculations." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/38003.

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The current shortage of crude oil from conventional sources has increased interest in developing unconventional resources such as oil sands. Heavy crudes and bitumen are found in Northern Alberta and their exploration, processing, and transport to market pose challenges in the use of these resources. Part of the solution to these challenges involves the reactive thermal processing of heavy crudes and bitumen. This thesis focused on mild thermal cracking reactions, and two studies regarding these reactions were presented. The first was an experimental study performed in a pilot-scale semi-batch reactor. The three crude oils were heated to 350, 400, 425, and 450°C at 1240 kPa. A five-lump reaction model combined with a process simulator with VLE calculations was fitted with the experimental data obtained. The goodness of fit between the model predicted values and experimental values for the Hardisty (MBL), Albian Heavy Synthetic (AHS), and Christina Lake Dilute Bitumen (CDB) were determined to be 0.99, 0.99, and 0.98, respectively. Moreover, 80, 85, and 89% of the optimized model’s predicted values had less than 10% error for MBL, AHS, and CDB, respectively. The second study described the implementation of a mild thermal cracking reaction model to the development of a train car fire-model for the assessment of safety aspects in the design of train cars used to transport crude oil. Case studies were conducted using the UniSim® depressuring utility and a previously developed mild thermal cracking reaction model to demonstrate the effect of compositional change. Three crude oils with varying properties and representative of the types of crudes transported by rail in Canada were used here: MBL, AHS, and CDB. The case studies conducted showed the performance of a train car fire-model to be dependent on the crude oil characteristics: up to -57% and -99% difference in model predicted variables for AHS and CDB, respectively, when compared to MBL. Furthermore, the model’s performance was also shown to be affected by the compositional change of a given crude oil due to mild thermal cracking reactions: up to 42% difference in model predicted variables when compared to the base case.
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Eude, Thibaut. "Forage des données et formalisation des connaissances sur un accident : Le cas Deepwater Horizon." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEM079/document.

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Le forage de données, méthode et moyens développés dans cette thèse, redéfinit le processus d’extraction de données, de la formalisation de la connaissance et de son enrichissement notamment dans le cadre de l’élucidation d’évènements qui n’ont pas ou peu été documentés. L’accident de la plateforme de forage Deepwater Horizon, opérée pour le compte de BP dans le Golfe du Mexique et victime d’un blowout le 20 avril 2010, sera notre étude de cas pour la mise en place de notre preuve de concept de forage de données. Cet accident est le résultat d’un décalage inédit entre l’état de l’art des heuristiques des ingénieurs de forage et celui des ingénieurs antipollution. La perte de contrôle du puits MC 252-1 est donc une faillite d’ingénierie et il faudra quatre-vingt-sept jours à l’équipe d’intervention pour reprendre le contrôle du puits devenu sauvage et stopper ainsi la pollution. Deepwater Horizon est en ce sens un cas d’ingénierie en situation extrême, tel que défini par Guarnieri et Travadel.Nous proposons d’abord de revenir sur le concept général d’accident au moyen d’une analyse linguistique poussée présentant les espaces sémantiques dans lesquels se situe l’accident. Cela permet d’enrichir son « noyau de sens » et l’élargissement de l’acception commune de sa définition.Puis, nous amenons que la revue de littérature doit être systématiquement appuyée par une assistance algorithmique pour traiter les données compte tenu du volume disponible, de l’hétérogénéité des sources et des impératifs d’exigences de qualité et de pertinence. En effet, plus de huit cent articles scientifiques mentionnant cet accident ont été publiés à ce jour et une vingtaine de rapports d’enquêtes, constituant notre matériau de recherche, ont été produits. Notre méthode montre les limites des modèles d’accidents face à un cas comme Deepwater Horizon et l’impérieuse nécessité de rechercher un moyen de formalisation adéquat de la connaissance.De ce constat, l’utilisation des ontologies de haut niveau doit être encouragée. L’ontologie DOLCE a montré son grand intérêt dans la formalisation des connaissances à propos de cet accident et a permis notamment d’élucider très précisément une prise de décision à un moment critique de l’intervention. La population, la création d’instances, est le coeur de l’exploitation de l’ontologie et son principal intérêt mais le processus est encore très largement manuel et non exempts d’erreurs. Cette thèse propose une réponse partielle à ce problème par un algorithme NER original de population automatique d’une ontologie.Enfin, l’étude des accidents n’échappe pas à la détermination des causes et à la réflexion sur les « faits socialement construits ». Cette thèse propose les plans originaux d’un « pipeline sémantique » construit à l’aide d’une série d’algorithmes qui permet d’extraire la causalité exprimée dans un document et de produire un graphe représentant ainsi le « cheminement causal » sous-jacent au document. On comprend l’intérêt pour la recherche scientifique ou industrielle de la mise en lumière ainsi créée du raisonnement afférent de l’équipe d’enquête. Pour cela, ces travaux exploitent les avancées en Machine Learning et Question Answering et en particulier les outils Natural Language Processing.Cette thèse est un travail d’assembleur, d’architecte, qui amène à la fois un regard premier sur le cas Deepwater Horizon et propose le forage des données, une méthode et des moyens originaux pour aborder un évènement, afin de faire émerger du matériau de recherche des réponses à des questionnements qui échappaient jusqu’alors à la compréhension<br>Data drilling, the method and means developed in this thesis, redefines the process of data extraction, the formalization of knowledge and its enrichment, particularly in the context of the elucidation of events that have not or only slightly been documented. The Deepwater Horizon disaster, the drilling platform operated for BP in the Gulf of Mexico that suffered a blowout on April 20, 2010, will be our case study for the implementation of our proof of concept for data drilling. This accident is the result of an unprecedented discrepancy between the state of the art of drilling engineers' heuristics and that of pollution response engineers. The loss of control of the MC 252-1 well is therefore an engineering failure and it will take the response party eighty-seven days to regain control of the wild well and halt the pollution. Deepwater Horizon is in this sense a case of engineering facing extreme situation, as defined by Guarnieri and Travadel.First, we propose to return to the overall concept of accident by means of an in-depth linguistic analysis presenting the semantic spaces in which the accident takes place. This makes it possible to enrich its "core meaning" and broaden the shared acceptance of its definition.Then, we bring that the literature review must be systematically supported by algorithmic assistance to process the data taking into account the available volume, the heterogeneity of the sources and the requirements of quality and relevance standards. In fact, more than eight hundred scientific articles mentioning this accident have been published to date and some twenty investigation reports, constituting our research material, have been produced. Our method demonstrates the limitations of accident models when dealing with a case like Deepwater Horizon and the urgent need to look for an appropriate way to formalize knowledge.As a result, the use of upper-level ontologies should be encouraged. The DOLCE ontology has shown its great interest in formalizing knowledge about this accident and especially in elucidating very accurately a decision-making process at a critical moment of the intervention. The population, the creation of instances, is the heart of the exploitation of ontology and its main interest, but the process is still largely manual and not without mistakes. This thesis proposes a partial answer to this problem by an original NER algorithm for the automatic population of an ontology.Finally, the study of accidents involves determining the causes and examining "socially constructed facts". This thesis presents the original plans of a "semantic pipeline" built with a series of algorithms that extract the expressed causality in a document and produce a graph that represents the "causal path" underlying the document. It is significant for scientific or industrial research to highlight the reasoning behind the findings of the investigation team. To do this, this work leverages developments in Machine Learning and Question Answering and especially the Natural Language Processing tools.As a conclusion, this thesis is a work of a fitter, an architect, which offers both a prime insight into the Deepwater Horizon case and proposes the data drilling, an original method and means to address an event, in order to uncover answers from the research material for questions that had previously escaped understanding
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Elrgaiye, Ali Saad Ab. "Semi-quantitative Risk Assessment of an anaerobic digestion process." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016.

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Biogas is the most emerging industrial sector for energy production from renewable sources at National and European levels, and growing government funds favor the development of its market. From a process safety standpoint, Seveso Directive (Directive 2012/18/EU of the European Parliament and of the Council), but Biogas plants are complicated enough to require both their specific technology and an accurate risk assessment for design purposes. The number of accidents involving biogas plants has been too many to be ignored. Biogas plants are often operated wrongly, deficient in technological details and incorrectly scaled-up. Moreover, all these mistakes are repeated over and over again. Therefore, there is the pressing need for an assessment of the reliability of these plants in order to operate them safely. For this reason, a quantitative risk assessment was carried out to on a biogas production plant. Starting from event trees conventional for process industry (EU- Project ARAMIS), to the critical events, and ending with selecting the specific reference accident scenarios.
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22

Peeters, Agnes. "Application of the Stimulus-Driven Theory of Probabilistic Dynamics to the hydrogen issue in level-2 PSA." Doctoral thesis, Universite Libre de Bruxelles, 2007. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210641.

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Les Etudes Probabilistes de Sûreté (EPS) de niveau 2 en centrale nucléaire visent à identifier les séquences d’événements pouvant correspondre à la propagation d’un accident d’un endommagement du cœur jusqu’à une perte potentielle de l’intégrité de l’enceinte, et à estimer la fréquence d’apparition des différents scénarios possibles.<p>Ces accidents sévères dépendent non seulement de défaillances matérielles ou d’erreurs humaines, mais également de l’occurrence de phénomènes physiques, tels que des explosions vapeur ou hydrogène. La prise en compte de tels phénomènes dans le cadre booléen des arbres d’événements s’avère difficile, et les méthodologies dynamiques de réalisation des EPS sont censées fournir une manière plus cohérente d’intégrer l’évolution du processus physique dans les changements de configuration discrète de la centrale au long d’un transitoire accidentel.<p>Cette thèse décrit l’application d’une des plus récentes approches dynamiques des EPS – la Théorie de la Dynamique Probabiliste basée sur les Stimuli (SDTPD) – à différents modèles de déflagration d'hydrogène ainsi que les développements qui ont permis cette applications et les diverses améliorations et techniques qui ont été mises en oeuvre.<p><p>Level-2 Probabilistic Safety Analyses (PSA) of nuclear power plants aims to identify the possible sequences of events corresponding to an accident propagation from a core damage to a potential loss of integrity of the containment, and to assess the frequency of occurrence of the different scenarios.<p>These so-called severe accidents depend not only on hardware failures and human errors, but also on the occurrence of physical phenomena such as e.g. steam or hydrogen explosions. Handling these phenomena in the classical Boolean framework of event trees is not convenient, and dynamic methodologies to perform PSA studies are expected to provide a more consistent way of integrating the physical process evolution with the discrete changes of plant configuration along an accidental transient.<p>This PhD Thesis presents the application of one of the most recently proposed dynamic PSA methodologies, i.e. the Stimulus-Driven Theory of Probabilistic Dynamics (SDTPD), to several models of hydrogen explosion in the containment of a plant, as well as the developed methods and improvements.<p><br>Doctorat en Sciences de l'ingénieur<br>info:eu-repo/semantics/nonPublished
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Bertilsson, Erik, and Egzon Latifi. "OLYCKSLASTER I ETT PREFABRICERAT FLERBOSTADSHUS." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-74950.

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Det här examensarbetet går ut på att jämföra EKS 11 och SS-EN 1991-1-7 olika beräkningsmodeller för olyckslaster. Ifall en byggnad endast har ett trapphus som enda nödutgång krävs det att den dimensioneras för olyckslaster. Dessa olyckslaster delas upp i två olika grupper, kända- och okända olyckslaster. Kända olyckslaster är exempelvis påkörning när byggnaden ligger nära en väg och explosion ifall det finns exempelvis gasledningar i byggnaden. Okända olyckslaster är de laster där man inte kan dimensionera för ett exakt värde. Istället dimensionerar man för att minska konsekvenserna av lasten där främsta alternativet är att använda de krav som ställs på väsentliga bärverksdelar och applicera dem på de bärande konstruktionsdelarna. Alternativt när byggnaden inte har gasledningar så kan man beräkna för okända laster genom att dimensionera via värdet som uppkommer från en gasexplosion, 34 kN/m2. Dimensioneringen anpassas efter ett verkligt projekt konstruerat av Structor. Tidigare problem har uppstått vid tolkning av eurokodens beräkningsgång och därför har eks 11 kommit med förtydliganden och med mer triviala lösningar kring olyckslaster. Beräkningsgången för de olika olyckslasterna ser olika ut beroende på om man följer eks 11:s metod eller eurokodens metod. Målet med arbetet är att förtydliga skillnaderna mellan de olika beräkningsgångarna och se vad som ligger till grund för dom. För att kunna skapa en bredare förståelse kring olyckslaster har eurokoden, EKS 11, litteratur och Structor varit till stor hjälp. Examensarbetet är avgränsat till olyckslaster när det bara finns ett trapphus som enda utrymningsväg där det sker en jämförelse mellan EKS 11 och SS-EN 19911-7. Resultatet visar att de två olika beräkningsgångarna ger två olika svar vid beräkning av både kända- och okända laster. Ekvationerna för att räkna fram olyckslaster i de olika standarderna tar hänsyn till olika saker vilket leder till olika resultat. Slutsatsen som går att dra är att det alltid finns olika förutsättningar för varje projekt. Därför bör det göras en riskanalys i projekteringsskedet för att avgöra vilken standard som ska användas för det aktuella projektet.<br>This dissertation is based on a comparison between the two different procedures on accidental actions in the Swedish norm EKS 11 and SS-EN 1991-1-7. If a construction only has a stairwell as the only emergency exit it requires that accidental actions determines. These accidental actions are categorized mainly to known and unknown accidental actions. Known accidental actions are for example collision by a vehicle or a gas leak from a gas pipe in the building. Unknown accidental actions are those loads that cannot be completely determined. Instead an analyze how to decrease the damage by accidental actions are used. The main approach is to value members as key elements, in effect making them strong enough to withstand a prescribed hazard loading. An alternative if the construction does not have any gas pipes is to use the pressure of 34 kN/m2 to represent the static equivalent from a notional gas explosion. The values in the work are based from a project constructed by the Swedish company Structor. Previously difficulties have occurred while comprehending the Eurocode’s calculation procedures therefore the new Swedish norm EKS have clarified a lot about accidental actions. The calculation procedures results in two different answers between the Eurocode and the Swedish norm EKS. The aim with this dissertation is too clarify the differences between them and perceive the reasons behind it. To be able to have a wider understanding of the subject accidental actions a screening has occurred of the Eurocode, the Swedish norm EKS and literature. The Swedish company Structor has also shared a lot of knowledge on the subject. The dissertation has been limited to accidental actions on stairwells as the only emergency exit and a comparison between the Swedish norm EKS 11 and SS-EN1-7. The outcome of the two different calculations shows two different results of the known and unknown accidental actions. The equations for calculating accidental action in the different standards considerate different things which leads to different results. The conclusion is that there always are different conditions in every project. Therefor a risk assessment should be done before the construction begins to determine which standard is the most suitable for the project.
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24

Spier, Chelsea L. "The fate and distribution of subsurface hydrocarbons released during the 2010 MC252 oil spill in deep offshore waters of the Gulf of Mexico." Scholarly Commons, 2012. https://scholarlycommons.pacific.edu/uop_etds/816.

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The explosion of the Deepwater Horizon oil platform on April 20, 2010 resulted in the second largest oil spill in history. In this study, the distribution and chemical composition of hydrocarbons within a 45 km radius of the blowout was investigated. A complete set of hydrocarbon data were acquired from the National Oceanic and Atmospheric Administration (NOAA) and from BP, including data from 16 research missions collected over eight weeks. The distribution of hydrocarbons was found to be more dispersed over a wider area in subsurface waters than previously predicted or reported. Several hydrocarbon plumes were identified including a near-surface plume (0.5 to 50 m), two small mid-depth plume (240 to 290 m and 850 to 880 m), and a large deepwater plume approximately 1,050 to 1,300 m below surface. Water soluble compounds were preferentially extracted from the rising oil in deepwater, and were found at potentially toxic levels both in and outside of areas previously reported to contain the majority of hydrocarbons. Data collected from different research missions were measured for a wide variety of chemical compounds, but not every sample was analyzed for the same chemical compounds. To overcome the challenge of variability in sample data, a non-parametric method of evaluating the percentage of detectable results, was used for all data analysis in addition to evaluation of total sample concentrations. The two analysis techniques yielded similar results. This approach may be useful in other studies in which samples are measured for varying number of compounds and have varying detection limits. The distribution and toxicity of hydrocarbons in sediments between August and October, 2010 was also investigated and was found to be fairly localized.
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25

NAGYOVÁ, Lenka. "Simulace havárie vozidla převážejícího výbušniny, její dopady a řešení." Master's thesis, 2014. http://www.nusl.cz/ntk/nusl-174261.

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The name and the topic of this diploma thesis, Crash simulation vehicle carrying explosives, impacts and solutions, illustrates its main goal. That is, using the TerEx software program, to simulate a crash of vehicle transporting explosives, the impacts resulting from such an incident and, as a secondary goal, to propose solutions of such an incident for the Emergency Service units, with the connection to public safety. After resolving these tasks, it will be possible to answer the research question: What are the dangers of a crash of vehicle transporting explosives? In the beginning, the theoretical part of the thesis focuses on explosives as such. The history of their inventions, usage and development is outlined. In the next chapter, explosives are defined as substances capable of explosive transformation that can release a large amount of energy in a very short time upon a sudden external impulse. For the classification of explosives, it was necessary to characterize types of explosive transformations and general principles that lead to releasing energy. Very important are then the theoretical chapters of this thesis, where are described in detail the effects and phenomena of an explosion, which are necessary for the identification of imminent harmful effects and impacts on the environment in the case of their unwanted initiation. These phenomena include shock wave, thermal and fragmentational effect, recoil, routing, blocking and multiplication of the shock wave. Follows the part, where explosives are classified according to various aspects, from which the most important is the aspect of speed of explosive transformation, which cardinally affects the explosives' properties. This part is followed by a chapter that describes those characteristics. The second half of the theoretical part is concerned with transportation of hazardous materials, especially explosives. Packing and marking requirements, duties of transportation participants and training of the participants are specified there. One must not forget traffic requirements and other necessities connected with transportation, including the need for accompanying documents, transport staff, traffic unit, its construction and equipment and the course of transportation. The last section of the theoretical part of this thesis is dedicated to specific rules of explosives' transportation, which in the Czech Republic are set by the law. It includes mainly a duty to notify the Police Prezidium of the Czech Republic at least 24 hours prior to transportation of explosives and the duty for the vehicle used for transportation to be equipped with a tracking device. In this sense the explosives are the only group of hazardous materials, for which these stricter rules apply. In order to find an answer to the research question, it was necessary in the empirical part of the thesis to gather input data for the TerEx program, where the event was then simulated. These data were collected by an analysis of usage and occurrence of explosives in the area of the South Bohemian region. On the basis of this analysis, a highly brisant explosive NKG-500, which is commonly used for quarrying, special destructive works, underwater tasks and for priming of industrial explosives. It is a place, where the density and complexity of traffic has not yet been tackled accordingly. On the basis of output from thus performed simulation it was possible to assess that in such a densely populated area with the large number of residential and administrative buildings an accident of vehicle transporting explosives poses a considerable threat. In connection with the threats and impacts discovered in relation with such an incident, a unified course of action of the Emergency Service for their solution was designed, whereupon specific actions of its respective units were considered.
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26

Baalisampang, T. "Evolving accident scenario modelling in complex processing facilities." Thesis, 2019. https://eprints.utas.edu.au/31432/1/Baalisampang_whole_thesis.pdf.

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Offshore oil and gas production and processing facilities are prone to incidents such as leakage which may escalate thus causing major accidents. These accidents pose a serious threat to personnel and assets. Previously, accident modelling has relied on studying a single event and its impact. It has been witnessed from past events that accidents are caused by combinations of events and therefore, accident modelling must consider multiple sequences of events and interdependent factors. The Floating Liquefied Natural Gas (FLNG) is a complex processing facility where a leakage of liquified natural gas (LNG) may escalate to a range of events such as fire to vapor cloud explosion. The escalation of events is dependent on the multiple intertwined factors evolving with time and space. This study is focussed on developing novel methodologies and models to study the transitional events and their causation during a major event in complex LNG processing facilities. This thesis outlined an extensive literature review and analysis of offshore and marine safety from the perspective of fire and/or explosion accidents. It analysed various causes of fire and/or explosion accidents and proposed a series of countermeasures with respect to different causes. The impact of the cryogenic temperature of LNG on steel structure during its accidental leakage has not been extensively studied. This study modelled an LNG pool formation and the impact of cryogenic temperature on a structural material during an accidental release of LNG. The study confirmed that an instantaneous LNG pool formation does cause immediate failure, however, this may significantly minimise design life of the structure and due attention is needed throughout its service life particularly in the spilled area. Literature review showed that minor leaks occur frequently, and they are often overlooked assuming that they are inconsequential. However, in the case of LNG, it can be too simple to ignore small leak due to the potentiality of causing suitable scenario for fire and explosion event upon rapid vaporisation after the leakage. This study proposed a novel technique for modelling fugitive leakage of LNG in a processing facility. The developed methodology is applied considering three different degrees of congestion and revealed that higher congestion levels present higher flammable hazards than the lower levels of congestion within the acceptable congestion level. As fire is the main cause of accident in oil and gas processing facilities, this study proposed a novel methodology for modelling fire impact assessment in a typical FLNG processing facility using Computational Fluid Dynamics (CFD). Three most credible fire accident scenarios were chosen from among various fire scenarios considered in the FLNG facility. It is found that the scenario in the Mixed Refrigerant Module in the liquefaction process presents the highest risk of fire to both on-board personnel and assets. In a complex processing facility, there is a high likelihood of occurrence of transitional scenarios such as hydrocarbon release, fire, explosion and dispersion of combustion products. Finally, this study modelled potential transitional events and their integrated impact during an accidental release of LNG. This study revealed that in a complex processing facility, transition of events is highly possible, and the impact of such events can be more severe than that of the individual event. This study serves as a comprehensive source of knowledge and technique on which to model various accident scenarios. The study of these scenarios assists in better understanding of accident causation and improves design to prevent causation of such events. The study also provides a practical approach to design safety measure to control and mitigate hazards when prevention is challenging. This thesis will serve as a guiding book to better design of processing facilities and safety measures for a complex processing facility.
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27

ZHANG, JIN-FENG, and 張晉逢. "Study of the Gas Explosion Accident of a Sewer via the 3D Risk Analysis Technique." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/nz6jkc.

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碩士<br>國立雲林科技大學<br>環境與安全衛生工程系<br>105<br>During the urbanization process of human beings, there are more and more public facilities and pipelines are buried in the ground due to various reasons. If not been properly regulated and managed, these pipelines may cause considerable hazards such as the explosion happened in the second largest city of Mexico, Guadalajara, in 1992, the Qingdao gas explosion accidents in 2013, and the Kaohsiung gas explosion in Taiwan, 2014. The situation also indicates the current staffs and the respond measures are insufficient for this kind of incidents. This research implements FLACS software to initiate a preliminary study for the underground pipelines. Different variables combinations (such as different sizes of obstacles used to simulate turbulent flow inside the culverts, wind field, ground buildings etc.) are applied to investigate overpressure, impulse pressure and temperature variation after explosion. Finally, maximum physical effects obtained from simulation are employed to calculate the death probability and the individual risk and their related images are output by the Matfor graphical software. Assuming under a circumstance without any protective measures, the thermal radiation casualties calculated at the most damaged intersection area is the most serious, where its death probability is above 75% and the personal of risk at the height of 2 meters is in the range of 0 (person / year) -14.6 (person / year). The simulation results show that the main cause of casualty and damage to the personnel and buildings around the explosion is the explosion overpressure and the pulse pressure. The high temperature is an indirect cause. Observing all scenarios, we found that FLACS is not an appropriate tool for event studies similar to the Kaohsiung airburst accident.
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28

Wu, Jung-Nan, and 吳榮男. "Accident Incident Crisis Management Research About The Second Ammunition Depot of Combined Logistics Command Explosion Case." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/08544000228594330925.

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碩士<br>中華大學<br>科技管理學系碩士班<br>98<br>To crisis management concepts, strategies, research joint logistics unit of accident casualties dangerous operating procedures for crisis management to crisis management analysis and strengthen the organization and effectiveness of implementation, and provide prevention strategies, objectives of this research. The research utilized the "document analysis", mainly for the Control Yuan of 93 years, "the joint logistics base for the second pool of refurbishing the ammunition" against the loss related to rectify the explosion, and cadres impeachment article and print media coverage of the literature review analysis of unit Enforcing ammunition management procedures and the interaction between the crisis and by Nunamaker stage theory framework of ammunition and symptoms of pre-crisis prevention, crisis, emergency and system change and crisis recovery as to support crisis Dynamic model relationship management, and then integrated the whole unit out of the joint logistics dangerous accident casualties careful as to better crisis management. Study found that: (a) accident casualties crisis management is a dynamic planning process; (b) accidents occurred emphasis on crisis management, crisis management, prevention before; (c) the impact of military casualties Subordinates causes of the crisis incident; ( d) accidents occurred under crisis management unit of the external environment factors. Finally, the crisis of academic Nunamaker dynamic model, the joint logistics command accidents occurred on the pre-crisis, with crisis after crisis as the three made the following recommendations for: (a) accidents occurred pre-crisis areas: 1. strengthen the discipline required personnel and cadre examination; 2. carefully revised operating procedures and knowledge base to establish a crisis; 3. the use of RFID to strengthen military logistics management; 4. to improve database storage and added security operating environment. (B) accidents occurred at the time of treatment: 1. Cadres crisis simulation training; 2. Attention to rank and file information processing education. (C) accidents occurred after the crisis of work: 1. To enhance staff morale and heart recovery unit; 2. Addendum to the Public Affairs budget to strengthen civil-military relations. Recommended by the study, as increased risk of joint logistics unit casualties incident crisis management performance of the reference.
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29

"Análisis de consecuencias y Zonas de Planificación para explosiones industriales accidentales (en el ámbito de las Directivas Seveso)." Universidad de Murcia, 2006. http://www.tesisenred.net/TDR-1019106-125534/.

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30

Wu, Chun-Hsien, and 吳俊賢. "Study of the 3D Risk Assessment Technique that Applied on the Gas Explosion Accident of Underground Pipelines." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/55244586167689754998.

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碩士<br>國立雲林科技大學<br>環境與安全衛生工程系<br>103<br>During the urbanization process of human beings, there are more and more public facilities and pipelines are buried in the ground due to various reasons. If not been properly regulated and managed, these pipelines may cause considerable hazards such as the explosion happened in the second largest city of Mexico, Guadalajara, in 1992, the Qingdao gas explosion accidents in 2013, and the Kaohsiung gas explosion in Taiwan, 2014. All these accidents lead to numerous casualties of firefighters; the situation also indicates the current staffs and the respond measures are insufficient for this kind of incidents. This research implements FLACS software to initiate a preliminary study for the underground pipelines. Different variables combinations (such as different sizes of obstacles used to simulate turbulent flow inside the culverts, wind field, ground buildings etc.) are applied to investigate overpressure, impulse pressure and temperature variation after explosion. Finally, maximum physical effects obtained from simulation are employed to calculate the death probability and the individual risk and their related images are output by the Matfor graphical software. Assuming under a circumstance without any protective measures, the thermal radiation casualties calculated at the most damaged intersection area is the most serious, where its death probability is above 75% and the personal risk is between 1.0010-6 (person/year) and 5.0010-3 (person/year).
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31

DE, MARCO ALESSANDRA. "Assessment of damage to people and buildings as consequence of hydrogen pipeline accidents." Doctoral thesis, 2020. http://hdl.handle.net/11573/1364105.

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Hydrogen is increasingly considered a valid alternative to traditional fuels, which are gradually being more and more depleted. It is defined as “the energy carrier of the future” and so, as such, it must be produced. Several hydrogen production technologies are widespread and they involve both traditional and innovative sources. After its production, the hydrogen must be made available for use and, so, it must be transported from the production site to the utilization site. One of the most common ways to transport considerable quantities of gaseous hydrogen is through pipelines. Since hydrogen is considered a “no safe” fuel due to its physical properties, the consequences of an accidental release must be investigated, to preserve the safety of people and facilities located in the surrounding area of a possible accidental event involving pipelines. Hydrogen disperses into the air very easily, being lighter than air, but if it is released in a confined space can result in an explosion. The hazards of the hydrogen-air mixture are related to the wide flammability range and the low minimum ignition energy. Furthermore, hydrogen burns with an invisible flame and so it is very difficult to suddenly identify the presence of danger. Based on these considerations, it results that a failure of pipeline conveying gaseous hydrogen can pose severe risks. The aim of this study is to evaluate damage to people and buildings involved in high-pressure hydrogen pipeline explosions and (jet) fires and, to this scope, a probabilistic risk assessment procedure is proposed. The annual probability of damage to people and to buildings exposed to an extreme event is calculated as the product of the conditional probability of damage given by a fire or an explosion and the probability of occurrence of the fire/explosion as consequence of pipeline failure. The consequences of hydrogen pipeline accidents are estimated through different tools: the SLAB integral model is used to define the gas dispersion, the TNO Multi-Energy Method to evaluate the overpressure and impulse generated from the explosions and Pressure-Impulse diagrams to evaluate damage to buildings. The flame length is calculated through the SLAB model by considering the length at which the hydrogen concentrations of 4% (lower limit flammability) is reached.The point source model is employed to estimate the radiative heat flux generated by jet fire with the radiant fraction calculated through the empirical correlation proposed by Molina et al. (2007). Finally, the Probit equations are used to calculate damage to people, both in the case of an explosion and a jet fire. The characteristic quantities of the two accidental events investigated, overpressure and impulse in the case of the explosions and radiative heat flux in the case of jet fires, are considered as causative variables. Reinforced concrete buildings and tuff stone masonry buildings are taken into consideration to estimate the effect of overpressure and impulse caused by an explosion. Direct and indirect damage on the people are investigated to define the effects of consequence of explosions and jet fires. The probabilistic procedure proposed can represent a useful tool in the design of a new hydrogen distribution network and in risks assessment for existing ones.
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32

Cho, Chao Wei, and 卓昭維. "A Comparison Study of the Underground Pipeline Regulatory Legal Systems of Petrochemical Industries between R.O.C. and U.S.A.—Observed from the Kaohsiung Gas Explosion Accident." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/93a2n2.

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碩士<br>國立政治大學<br>法律科際整合研究所<br>104<br>Kaohsiung Gas Explosion Accident, occurred on Jul. 31, 2014, caused serious damages. In this thesis, the author investigated the related issues, examined the related legal systems and summarized the related proposal of bills in the Legislative Yuan. In addition, the author introduced United States Code and furthermore compared the underground pipeline regulatory legal systems between R.O.C. and U.S.A. Finally, the author provided legislative suggestions to pipeline safety management. According to United States Code, the safety of gas and hazardous liquid pipelines are managed by PHMSA—an administration under the Department of Transportation. There is a series of fairly complete regulatory laws and authorities in 49 USC SubtitleⅧ—Pipeline, including the materials, designs and constructions, qualification of operation of pipeline, training of operation personnel, inspection of pipelines, maintenance, disclosure of operation information and damage prevention, and the response plans when accident happens. There are various ways for administration to manage pipeline safety. National pipelines mapping system is built up such that people can inquire for more detailed information so as to prevent the damage. One-call notification systems are built up so as to prevent the probability of pipeline damages during excavation. Moreover, there are Civil and Criminal penalties in 49 USC SubtitleⅧ. This thesis indicated that there are many differences between the regulations in R.O.C and U.S.A.. It is found the regulations to the management of petroleum industry in R.O.C. are deficient. Therefore, three legislative suggestions were provided: (a)To stipulate a particular regulation for the petrochemical and similar pipelines outside the factories; (b)To establish substantial management measurements explicitly; and (c)To apply penalty policy when it is appropriate.
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