Dissertations / Theses on the topic 'Perth Basin'

The Early Permian coal samples for the study were obtained from the Vasse Shelf, southern Perth Basin, located approximately 200 km south- west of Perth. The selected coal samples for the study were also obtained from the Premier Sub-basin of the Collie Basin and the Irwin Sub-basin of the Perth Basin. The Early Permian coal measures are described as the Sue Coal Measures from the Vasse Shelf, the Ewington Coal Measures from the Premier Sub-basin and the coal measures from the Irwin sub-basin are described as the Irwin River Coal Measures.The Vasse Shelf coal is finely banded and the dominant lithotypes are dull and dull banded types, followed by bright banded and banded types, with minor bright types. The variation of dull and bright lithotypes represents fluctuating conditions of water table level during the growth of peat in the swamp. The maceral composition of the coal is predominantly composed of inertinite, followed by vitrinite and minor exinite and mineral matter. The coal is characterized by very low to medium semifusinite ratio and medium to high vitrinite content, supporting the deposition in anaerobic wet conditions with some degree of oxidation. The coal is classified as sub- bituminous to high volatile bituminous of the Australian classification. In terms of microlithotype group, the predominance of inertite over vitrite suggests the coal was formed under drier conditions with high degree of oxidation during its deposition. On the basis of the interpretations of lithotypes, macerals, microlithotypes and trace elements, the depositional environment of the coal is braided and meandering deltaic-river system without any brackish or marine influence.The maceral composition of the Collie coal predominantly consists of inertinite and vitrinite, with low exinite and mineral matter. The very low to low semifusinite ratio and low to medium vitrinite content of ++
the coal indicate that the coal was formed under aerobic dry to wet conditions with some degree of oxidation. The coal is categorized as sub-bituminous according to the Australian classification. The domination of inertite and durite over vitrite and clarite contents in the coal reflects the deposition under drier conditions with fluctuations in the water table. On the basis of the interpretations of macerals, microlithotypes and trace elements distribution, the depositional environment of the coal is lacustrine, braided to meandering fluvial system, without the influence of any marine influx.The maceral composition of the Irwin River coal consists predominantly of vitrinite and inertinite, and minor exinite and mineral matter. The coal has very low semifusinite ratio and medium to high vitrinite content, suggesting the coal was deposited in anaerobic wet conditions with some degree of oxidation. The coal is classified as sub-bituminous of the Australian classification. The predominance of vitrite and clarite over inertite and durite contents in the coal indicates that the coal was formed in wetter conditions and in high water covers with a low degree of oxidation. Based on macerals and microlithotypes contents, the depositional environment of the coal is braided fluvial to deltaic, which is in accordance with the interpreted non- marine and mixed marine environment of deposition in the sub-basin.The petrological comparisons of Vasse Shelf, Collie and Irwin River coals show that the average vitrinite content of the Irwin River coal is highest (49.1%) and of the Collie coal is lowest (37.3%) of the three. The inertinite content is highest in Collie coal (49.1%), followed by Vasse Shelf (46.4%) and Irwin River (39.2%) coals. The exinite content is low in Irwin River coal (6.3%) as compared with Vasse Shelf (9.0°/,) and Collie (8.3%) coals. The mineral matter content ++
is relatively low for all the three coals. The rank of the Vasse Shelf coal is high as compared with the Collie and Irwin River coals, either due to tectonic uplift after the deposition in post-Permian in the southern Perth Basin, or due to the average depth of burial over Vasse Shelf which is much greater than that of Collie and Irwin River coals.The comparisons of the coal from Western Australia with the selected Gondwana coals show that the predominance of inertinite over vitrinite occurs in the Western Australian coals (Vasse Shelf and Collie Basin). On the other hand, the Brazilian, eastern Australian, Indian and Western Australian (Irwin Sub-basin) coals are dominated by vitrinite over inertinite. The exinite content is highest in the Indian coals and lowest in the eastern Australian coals. The mineral matter content is highest in the Brazilian and Indian coals, and lowest in Western Australian (Vasse Shelf) and eastern Australian (Sydney Basin) coals. The rank of the coals ranges from sub- bituminous to medium volatile bituminous according to the Australian classification.

The Early Jurassic coal samples for the study were obtained from CRA Exploration Pty Ltd. (CRAE), drilled in the Gairdner and Mintaja Blocks, Gairdner Range of the Hill River Area, northern Perth Basin, Western Australia. The area is located approximately 280 km north of Perth. The coal measures subcrop in a half- graben bounded by the Lesueur-Peron Fault in the west, and the Warradarge Fault in the east. The coal occurs within the shallow sequence of the Cattamarra Member which is also described as the Cattamarra Coal Measures of the Cockleshell Gully Formation.Six sub-seams of seam G, namely G1 to G6, from the six drill cores, were examined for petrological and geochemical investigation. The coal predominantly comprises of banded, dull banded, and dull lithotypes, with minor bright banded, bright and fusainous types. Based on maceral analyses, the dominant maceral groups are vitrinite and inertinite, whilst the exinite and mineral matter are in minor contents. The vitrinite content has a range between 47.2 % to 73.0 %, and it is composed mainly of telocollinite and desmocollinite. The inertinite is dominated by semifusinite, fusinite, and inertodetrinite, and it has a range from 10.4 % to 24.8 %. The exinite group varies between 7.2 % to 20.8 % in content, and it is represented by sporinite, cutinite, alginite and resinite. The mineral matter dominated by clays and pyrite, ranges between 4.5 % to 20.6 %. The microlithotype analyses shows that the vitrite plus clarite content varies from 47.0 % to 70.0 %, intermediates between 8.0% to 26.0 %, whilst inertite plus durite content is relatively low, varying from 6.55 % to 14.0 %. The maximum reflectance of vitrinite has a value between 0.47 % and 0.53 %, which represents rank at sub-bituminous level based on the Australian rank values and corresponding to the sub-bituminous A and B rank of the ASTM classification and ++
to the metalignitous type of the Pareek classification. On the basis of carbon and hydrogen content, the coal is categorised as per-hydrous meta- to ortho-lignitous type. The trace elements As, B, Be, Cd, Co, Cr, Cu, Ga, Mn, Mo, Ni, Pb, Sr, Th, U, V, Y, Zn, and Zr, are spectrographically analysed in the coal ash. The B content in the coal supports the presence of marine influence during peat deposition in the basin.On the basis of lithotype, maceral, microlithotype, trace element distribution, pyrite and total sulphur in the coal, the depositional environment for coal and the coal measures, is interpreted as an upper to lower delta type within a regressive phase of marine transgression.

The Sakmarian (Cisuralian, Permian) Fossil Cliff Member of the Holmwood Shale is situated in the northern Perth Basin, Western Australia, and consists of alternating beds of shale and silty calcarenite forming three parasequences. Within this member a diverse fauna of ostracodes and foraminifera are present. During the Cisuralian the northern Perth Basin formed part of the Gondwanan supercontinent and was linked to Greater India via an epeiric sea that opened to the north. The ostracode fauna is restricted to the calcareous beds of the member and consists of a diverse benthic fauna comprising 31 new species and 13 previously recorded species. Species from the Healdioidea, Bairdioidea, Youngielloidea, and Thlipsuroidea dominate the assemblage and suggest a normal-marine environment during the period represented by the calcareous beds, with an overall shallowing trend up the sequence. The fauna shows some similarity to faunas from the Tethyan deposits of North America and the Boreal deposits of Russia during the Late Carboniferous and Cisuralian. Twenty-eight species of foraminifera were recorded from the Fossil Cliff Member and underlying Holmwood Shale and comprise two distinct faunas, an agglutinated benthic foraminiferal fauna found within the shale beds and a calcareous benthic foraminiferal fauna present in the calcarenite units. The agglutinated foraminifera are inferred to represent deposition in dysoxic to suboxic (0.1-1.5 mL/LO2;), poorly circulated bottom waters below wave base. The calcareous foraminifera are inferred to represent deposition in normal-marine conditions. Both foraminiferal assemblages show a shallowing trend in their distribution that matches the trend identified in the ostracode fauna. Based upon the palaeoecology of the ostracode and foraminiferal faunas, the depositional environment for the Fossil Cliff Member is inferred to have been within shallow water in an epeiric basin during an overall marine regression that is overprinted by eustatic and isostatic oscillations resulting from deglaciation that occurred during the early Sakmarian (Cisuralian). These sea-level oscillations raised and lowered the oxic surface waters of the epeiric sea above and below the substrate resulting in a sparse agglutinated foraminiferal fauna or an abundant and diverse ostracode and calcareous foraminiferal fauna respectively.

Dams and weirs are widely implicated in large-scale declines in both the range and abundance of aquatic fauna. Although many factors are involved, such declines are commonly attributed to the prevention or reduction of migration, reductions in available habitat, alteration of natural flow regimes and changes to physicochemical characteristics. In Australia, studies into the ecological effects of these impacts are limited, and have concentrated mainly on species of recreational and commercial importance. Subsequently, the adverse effects of dams and weirs, and suitable methods of mitigation, remain largely unknown for many other taxa. Therefore, the major aim of this thesis is to investigate the ecological effects of dam and weir construction on previously unstudied migratory assemblages of fish and macroinvertebrates in the Murray-Darling Basin. It is anticipated that the results of these studies will feed back into improved management strategies that help arrest the previously observed declines of aquatic fauna. Initially, fish communities were sampled, by boat electrofishing, from both reference sites and downstream of Balranald and Redbank weirs on the lower reaches of the Murrumbidgee River, Australia. Sampling was stratified over large spatial and temporal scales to gain a comprehensive understanding of species most affected by the presence of these two barriers. In general, the weirs obstructed fish migrations during summer and autumn and many species of small-bodied fish such as Australian smelt, western carp gudgeon, fly-specked hardyhead and crimson-spotted rainbowfish accumulated downstream of Balranald Weir. In addition, downstream accumulations of juveniles of larger-bodied species such as bony herring, common carp and goldfish were also detected. Although many previous studies had either documented or hypothesised that upstream migrating fish accumulate downstream of migration barriers, none attempted to quantify the size of such populations. Therefore, a simple but efficient method to estimate the size of migratory populations was assessed at the Balranald Weir site. The application of two commonly used estimation techniques yielded relatively reliable results for seven species that accumulated downstream of the weir. Population size estimates were greatest for most species during summer and autumn, where accumulations as high as 800 fish per day were detected. The largest calculated population size estimates, in addition to the greatest temporal variation, of any individual species was observed in bony herring. Given the simplicity of the technique and the relative accuracy of population estimates, it was concluded that these methods could easily be applied to other weirs where the size of migratory populations is of particular interest. A study investigating the effects of Yanco Weir on the diets of three migratory percichthyid species, Murray cod, trout cod and golden perch was also conducted. Observed spatial variation in a number of trophic processes strongly implicated Yanco Weir as a major contributor to increased competition among percichthyid species on the Murrumbidgee River. The greater relative abundance of percichthyids from downstream samples, combined with increases in dietary overlap and a greater percentage of empty stomachs, also suggested percichthyids may be significantly affecting the relative abundance of potential prey items such as freshwater prawns and Australian smelt. These significant changes in dietary composition were likely related to migratory behaviour, as these species accumulated downstream of the weir, and could be readily expected at other sites where passage is obstructed. It was suggested that the construction of suitable fish passage facilities would effectively reduce the probability of migratory fish accumulating and, subsequently, potential effects of dams and weirs on trophic processes. Since it was established that dams and weirs of the Murrumbidgee River were significantly affecting migratory fish communities, an innovative but relatively inexpensive fishway design, the Deelder fish lock (after Deelder, 1958), was constructed and assessed for wider application throughout the Murray-Darling Basin. The Deelder lock was effective at mitigating the effects of Balranald Weir by providing passage for a wide range of size classes and species of fish; but importantly, the structure enabled the passage of most species previously observed to accumulate downstream of the structure. Most significant was the ability of the fish lock to pass substantial numbers of small-bodied fish, which were previously not considered migratory, suggesting that these species should be considered when developing options to mitigate the effects of other dams and weirs throughout the Murray-Darling Basin. A significant finding of this study was the realisation that substantially more species and size classes of Australian native fish are migratory than previously thought. Subsequently, it is recommended that, when designing facilities to mitigate the effects of a dam or weir, the structure of the entire migratory community is considered when developing operating parameters. Various options for mitigating the effects of dams and weirs are discussed, but it was concluded that the construction of effective fishways would be the most appropriate means of restoring migration pathways to Australian native fish. A strategic approach for assessing and adaptively mitigating the effects of dams and weirs is presented and discussed.

Les processus microbiens de nitrification et de denitrification ont ete etudies dans les sediments du bassin d'arcachon, une lagune macrotidale situee dans le sud-ouest de la cote atlantique francaise colonisee par des phanerogames marines (z. Noltii). Les densites de populations des bacteries nitrifiantes ont ete estimees par la methode du npp. Les densites sont faibles, comprises entre 10#2 et 10#4 bacteries par ml de sediment, et montrent une legere augmentation durant la periode hivernale. L'activite nitrifiante a ete evaluee par la methode d'accumulation d'ammonium apres blocage a la n-serve. Les activites sont generalement faibles allant de 0 a 90 mol m#-#2 h#-#1. Pour les sediments intertidaux, la nitrification represente 120 a 140 mmol m#-#2 an#-#1. La denitrification a ete evaluee sur l'ensemble du bassin par l'utilisation de nitrates marques a l'azote 15 (#1#5n isotope pairing technique). Les activites moyennes sont faibles : de 10 a 20 mol m#-#2h#-#1 avec un maximum de 75 mol m#-#2h#-#1. Generalement, l'activite denitrifiante est soutenue l'ete par l'activite nitrifiante couplee. Au contraire, l'hiver ce sont les nitrates diffusant de la colonne d'eau qui sont principalement denitrifies. Le bilan des processus internes bacteriens du cycle sedimentaire de l'azote montre que la nitrification represente de 3 a 14%, la denitrification de 12 a 24% et la fixation d'azote de 3 a 16% des apports en sels azotes dissous dans la lagune. L'impact des processus bacteriens sur le cycle global de l'azote du bassin est donc faible comparativement aux apports externes azotes et a l'assimilation d'azote par les phanerogames marines.

Six rivers within the upper Mumbidgee catchment were sampled for larval and juvenile fish. The rivers represented both regulated and unregulated flow regimes and varied widely in size. There was wide variation in the larval fish communities supported by each river, both in terms of the species diversity and total abundance of fish sampled. The highly regulated reach of the Mumbidgee River sampled during this study had the highest numbers of native species and native individuals of any river sampled. In the two rivers selected for further study, the Murmmbidgee and Goodradigbee, there was a high level of inter-annual consistency in the species composition within the reaches sampled, despite considerable change in the temperature and flow regimes of both rivers. This indicates that at least some spawning of those species sampled may occur each year, regardless of environmental conditions. Estimates of the relative abundance of each species sampled changed markedly between years, and it is argued, on the basis of growth information contained in the otoliths, that differential survival of larvae and juveniles was largely responsible for this shift in relative abundance. Otolith microstructure provided information on the date of spawning and early growth patterns of all species sampled in the upper Mumumbidgee catchment. In addition to determining the age and thus 'birth-date' of an individual, the effect of a particular event or series of events has on growth, and subsequent survival, is permanently recorded in the otolith microstructure. This enables accurate back-calculation and correlation to management actions or natural events. No other research tool has this ability to retrospectively assess, on a daily basis, the impacts of management actions on condition and subsequent survival of fish larvae. Species sampled could be separated into three groups based on spawning requirements; those linked with flow, those linked with temperature and generalist species that appear to have river independent cues, such as photoperiod or moon phase. Patterns in growth rate during the early life history stages enabled quantification of the consequences of variation in environmental conditions on the survival and recruitment of various species. Growth was not always highly correlated with water temperature, in fact, for mountain galaxias, high temperatures appear to negatively affect larval condition and subsequent survival. Conversely, carp exhibited a strategy more consistent with common perceptions, with growth and survival increasing with increasing temperature. The study uncovered spawning and growth patterns that were unexpected. Age analysis of western carp gudgeon demonstrated that they had undertaken a mid-winter spawning, when the water temperature in the main channel was far lower than that at which spawning was previously recorded for this species. Redfin perch from the unregulated Goodradigbee River exhibited growth rates exceeding the published upper limits for this and other closely related species. This growth could not be correlated with either temperature or flow, indicating that there are additional factors that dominate growth rates of redfin perch in the Goodradigbee River. The proportion and abundance of native species alone is not necessarily indicative of a 'healthy' or pristine system; some native species may be positively affected by river regulation, at least as juveniles. Comparison of the current larval fish community with likely pre-European fish communities does provide an indication of change to the system. The results of this study suggest that larval fish growth rates can be strongly influenced by environmental conditions, thus providing a powerful tool for monitoring future change and the factors which cause it. This study has demonstrated the value of larval and juvenile fish age and growth information, derived from otolith microstructure techniques, for many aspects of river management. Current river management priorities for which these techniques provide unique information include the determination of environmental flow regimes and the control of undesirable exotic species such as carp.

Dans la plupart des sociétés modernes, se laver est considéré comme une activité essentielle. Or, 31% des aînés vivant à domicile présentent des difficultés à prendre leur bain. Dans ces situations, l'ergothérapeute est l'expert pour évaluer les causes des problèmes rencontrés et le cas échéant, recommander l'ajout d'équipements au bain. Cependant, dans un contexte de pénurie de ressources humaines et face au nombre croissant de demandes de services, les ergothérapeutes ne suffisent plus à la tâche. Certains établissements de santé ont donc développé de nouveaux modèles d'organisation clinique qui impliquent l'auxiliaire aux services de santé et sociaux (ASSS) lors de la détermination du besoin d'équipements. Cette politique institutionnelle d'inclusion du personnel auxiliaire présente deux avantages: (1) les ASSS sont en mesure d'évaluer leurs propres conditions de travail ce qui diminue le risque de lésions professionnelles et (2) leur implication favorise le maintien de leur santé mentale par la reconnaissance de leurs compétences. L'objectif de cette étude consistait à valider l'algorithme Préalables aux soins d'hygiène, un outil de travail qui guide les observations de l'ASSS lors de la détermination du besoin d'équipements an bain ou à la douche des personnes en perte d'autonomie vivant à domicile. Plus spécifiquement, le projet visait à (1) établir la capacité d'une ASSS qui utilise l'algorithme à identifier les situations cliniques qui relèvent de sa compétence, (2) mesurer la concordance entre les recommandations émises par l'ergothérapeute (critère) et celles formulées par l'ASSS qui utilise l'algorithme et (3) comparer la concordance en fonction du contexte dans lequel s'inscrit la demande: nouvelles demandes vs réévaluations des services. Des personnes incapables de se laver seules sans difficulté (n=96) ont tout d'abord été évaluées par l'ergothérapeute à leur domicile. Par la suite, à moins d'une semaine d'intervalle, une ASSS utilisant l'algorithme a rencontré les participants. Pour s'assurer de l'intégrité des données, l'ergothérapeute a transmis ses recommandations à l'insu de celles émises par l'ASSS et vice versa. Les participants, en majorité des femmes (68%), étaient âgés en moyenne de 77 ans et vivaient avec un proche. La sensibilité de l'ASSS qui utilise l'algorithme à identifier les situations qui relèvent de sa compétence est de 96% tandis que la spécificité est de 69%. La concordance entre les recommandations des deux intervenants varie de substantielle à presque parfaite pour le lieu ([delta]=0,93 [0,85 ; 1,00]) ainsi que pour le besoin d'une barre d'appui ([delta]=0,77 [0,63 ; 0,91]) tandis qu'elle varie de passable à modérée (Kp =0,63 [0,52 ; 0,75]) pour le siège de bain. Il n'y a pas de différence significative lorsque la concordance entre les recommandations est comparée en fonction du contexte (nouvelles demandes vs réévaluations). Ainsi, l'ASSS qui utilise l'algorithme identifie correctement les situations qui relèvent de sa compétence, le lieu où l'hygiène doit être complétée ainsi que le besoin d'une barre d'appui. Afin d'augmenter l'accord pour le siège de bain, it est recommandé de retirer de l'algorithme la possibilité de choisir certains modèles moins fréquemment utilisés. Les résultats de l'étude augmentent la confiance face à l'algorithme et encourage l'inclusion de l'ASSS dans le processus de détermination du besoin d'équipements au bain. Ce nouveau modèle d'organisation clinique est prometteur car il favorise l'accès à des services de santé de qualité en plus d'avoir une incidence positive sur la santé et la sécurité des ASSS.

Le contexte environnemental actuel conduit l’industrie aéronautique à considérer de nouveaux critères de développement. D’une part, les gouvernements exigent des réductions d’émissions de polluants et d’autre part, les clients, c’est-à-dire les avionneurs, poussent à réduire les consommations de carburants. Ces deux objectifs peuvent être atteints grâce à l’amélioration des performances énergétiques. A ce titre, il est important de comprendre et de quantifier les pertes générées dans les systèmes de transmission de puissances. L’objectif de l’étude présentée dans ce manuscrit est de modéliser les pertes de puissance d’une boîte de transmission arrière d’hélicoptère. Ces boîtes sont généralement caractérisées par la présence d’un engrenage à renvoi d’angle spiro-conique et d’une lubrification par bain d’huile. Une campagne de tests sur un banc d’essai élémentaire a été effectuée afin de mesurer le couple résistant de roues dentées spiro-coniques en rotation dans un bain d’huile. Un phénomène peu commun sur l’évolution du couple avec la vitesse de rotation a été observé. A partir de ces résultats, un modèle analytique simple a été développé pour le calcul de la perte de puissance. Ce modèle a ensuite été validé sur une application réelle de boîte de transmission d’hélicoptère, pour laquelle des mesures de couple résistant et de températures ont été effectuées
The current environmental context is driving the aeronautic industry towards new design criteria. On the one hand, governments demand emission reductions of pollutants and on the other hand, customers, i.e. aircraft manufacturers, are pushing to reduce fuel consumption. Both of these goals can be achieved through efficiency improvements. As such, it is important to understand and quantify losses generated in power transmission systems. The objective of this study is to model the power losses of an helicopter tail gearbox. These gearboxes are generally characterized by the presence a spiral bevel gear and oil bath lubrication. A test campaign on an elementary test bench was carried out to measure the resistive torque of spiral-bevel wheels rotating in an oil bath. An uncommon evolution of the torque with the rotational speed was observed. From these results, a simple analytical model has been developed for the calculation of power losses. This model was then validated on a tail helicopter gearbox application, for which resistive torque and temperature measurements were made

Les effets dominos ou cascade d’événements dans les industries et particulièrement dans les industries chimiques et de transformation, sont reconnus comme des scénarios d’accidents possibles depuis environ trois décennies. Ils représentent une préoccupation croissante, car ils ont le potentiel de provoquer des conséquences dévastatrices. L’effet domino, comme phénomène, est un sujet controversé lorsque son évaluation est nécessaire. L’examen de la bibliographie a démontré l’absence d’une définition commune et d’une procédure simple d’utilisation et précise pour son appréciation. C’est pourquoi l’un des objectifs de cette recherche est de formaliser les connaissances relatives aux effets dominos afin de comprendre les mécanismes de leurs occurrences. Pour ce faire nous avons étudié les paramètres à examiner pour déterminer la possibilité de cascade et être en mesure d’identifier les scénarios dominos. L’enjeu étant de permettre l’amélioration de la prévention du risque d’effet domino. L’autre objectif est donc de produire une méthode pour l’identification et l’analyse des effets dominos. Nous avons développé une méthodologie globale pour l’étude des effets dominos en chaîne initiés par des pertes de confinement. Elle permet l’identification et la hiérarchisation des chemins de propagation des accidents. Cette méthode facilite la prise de décision pour la prévention des effets dominos, tout en proposant un outil efficace et simple d’utilisation. Les résultats de l’étude sont fournis sous forme d’une hiérarchisation quantitative des équipements impliqués dans les scénarios dominos, en tenant compte des effets des conditions météorologiques et des mesures de maîtrise des risques existantes ou proposées.Cette hiérarchisation donne une idée claire des dangers que représentent les équipements par rapport aux accidents en cascade, en précisant si la dangerosité de l’équipement provient de sa capacité à initier ou à propager un effet de cascade.La méthode est basée sur une description topographique de la zone étudiée, incluant les caractéristiques de chaque équipement, et prend en compte les mesures de maîtrise des risques mises en œuvre par l’industriel. Elle repose sur deux phases principales : La première, est l’identification des chemins de propagation des accidents. Pour ce faire, la méthode d’analyse par arbre d’événements est utilisée. Les cibles potentielles sont déterminées en combinant les valeurs seuils d’escalade et les modèles de vulnérabilité (pour l’estimation de la probabilité d’endommagement). Cette première phase est implémentée sous MATLAB® et Visual Basic for Applications (VBA) afin de faciliter l’entrée des données, et l’analyse des résultats dans Microsoft Excel®. La deuxième phase est l’identification des équipements les plus dangereux vis-à-vis des effets dominos. Elle consiste à hiérarchiser les équipements impliqués dans les chemins de propagation, en fonction de leur vraisemblance à causer ou à propager un effet domino. L’algorithme qui effectue cette phase est codé sous VBA. La méthode a été conçue de façon à ce qu’elle puisse être utilisée sans qu’il soit nécessaire de s’appuyer sur les résultats des études de dangers. Néanmoins, si ces résultats sont disponibles, il est alors possible d’alléger certaines étapes de la méthode. Elle s’est révélée facile à utiliser, cela a été constaté lors de son application dans le cadre de projets et stages d’étudiants
Domino effects or cascading events in the chemical and process industries are recognized as credible accident scenarios since three decades. They are raising a growing concern, as they have the potential to cause catastrophic consequences. Domino effect, as phenomenon, is still a controversial topic when coming to its assessment. There is still a poor agreement on the definition of domino effect and its assessment procedures. A number of different definitions and approaches are proposed in technical standards and in the scientific literature. Therefore, one of this research objectives is to formalize domino effects knowledges in order to comprehend their occurrence mechanisms. Thus, the parameters that should be looked at so as to understand the escalation possibility and in order to identify domino scenarios, were analyzed. The aim is to improve domino effect hazards prevention, through the development of a methodology for the identification and the analysis of domino effects.We developed a method for the analysis of domino accident chain caused by loss of containments. It allow the identification and prioritization of accident propagation paths. The method is user-friendly and help decision making regarding the prevention of cascading events. The final outcomes of the model are given in form of quantitative rankings of equipment involved in domino scenarios, taking into account the effect of meteorological conditions and safety barriers. The rankings give a clear idea of equipment hazard for initiating or continuing cascading events.The methodology is based on a topography of the industrial area of concern, including the characteristics of each unit and accounting for protection and mitigation barriers. It is based on two main stages. The first is the identification of accident propagation paths. For this, the event tree method is used. The possible targets are identified combining the escalation thresholds and vulnerability models (to estimate damage probability). This first stage was implemented using the MATLAB® software and Visual Basic for Applications (VBA) to enable an easy input procedure and output analysis in Microsoft Excel®.The second stage is the identification of the most dangerous equipment. It consists in prioritizing equipment involved in the propagation paths according to their likelihood to cause/propagate domino effect. The algorithm that performs this phase was coded in VBA.The method was designed so as it can be used without the need to rely on the results of safety reports. However, if such results are available, it is possible to lighten some steps of the method. It revealed easy to apply, this was confirmed through projects and student internships
Gli effetti domino, in cui un primo incidente causa in cascata altri scenari incidentali, sono tragli scenari incidentali più severi che avvengono nell’industria chimica. Nonostante l’attenzioneche anche la normativa dedica a tali scenari, la valutazione dell’effetto domino è un soggettocontroverso. L’analisi della letteratura tecnica e scientifica ha mostrato l’assenza di unadefinizione comune di « effetto domino » e di una semplice procedura per l’identificazione ditali scenari. È per tale motivo che uno degli obiettivi di questo lavoro di ricerca è diformalizzare le conoscenze relative agli effetti domino al fine di meglio comprendere imeccanismi che possono provocarli. A tal proposito sono stati studiati i parametri necessariper determinare la possibilità dell’insorgere di cascate di eventi e per essere in grado diidentificare i possibili scenari incidentali dovuti ad effetto domino. L’obiettivo finale del lavoroè stato di sviluppare un metodo per l’identificazione e l’analisi quantitativa della propagazionedi incidenti primari nell’ambito di scenari dovuti ad effetto domino.E’ stata sviluppata una metodologia generale per l’analisi degli effetti domino causati daperdite di confinamento. Tale metodologia permette l’identificazione e la classificazione deipercorsi di propagazione degli incidenti. Tale metodo facilita inoltre la prevenzione deglieffetti domino, proponendo uno strumento efficace e semplice da utilizzare.I risultati di questo studio sono forniti in forma di una classificazione delle apparecchiaturecoinvolte in scenari dovuti ad effetto domino, tenendo conto degli effetti delle condizionimeteorologiche e delle misure esistenti per la gestione del rischio. Tale classificazione fornisceanche un chiara idea dei pericoli rappresentati dalle singole apparecchiature nel caso diincidenti in cascata, in quanto precisando se la pericolosità delle attrezzature proviene dallaloro capacità di innescare o propagare un reazione a catena.Il metodo è basato su una descrizione topografica del sito studiato, che comprende anche lecaratteristiche di ogni attrezzatura, che tiene conto delle misure di gestione dei rischi e dellebarriere di sicurezza presenti, basato su due fasi principali. La prima è l’identificazione deipercorsi di propagazione degli incidenti. A tale scopo è stato utilizzato un metodo basatoVIsull’albero degli eventi. I potenziali bersagli vengono determinati combinando i valori di sogliaper la propagazione degli eventi ed i modelli di vulnerabilità delle apparecchiature. Questaprima fase è implementata in MATLAB® e Visual Basic for Applications (VBA) in modo dafacilitare la gestione dei dati e l’analisi dei risultati in Microsoft Excel®.La seconda fase è l’identificazione delle apparecchiature più pericolose per gli effetti domino.Tale fase consiste nel classificare le apparecchiature coinvolte nei percorsi di propagazione infunzione della loro capacità di causare o propagare un effetto domino. L’algoritmo dedicato inquesta fase è eseguito su VBA.I risultati ottenuti anche nell’applicazione ad un caso di studio hanno evidenziato le potenzialitàdel metodo, che rappresenta un significativo progresso nell’analisi quantitativa dell’effetto domino

碩士
逢甲大學
土木及水利工程研究所
88
This study takes network technique by using optiminization method to optimize the reservoir operation and distribution for the allotment planning of water resources system management . First, we use multiobjective planning and network analysis from system analysis as a tool to allot the water resources. From that We establish a decision model. This model based on PERT/CPM method within the limited quantity of water resources to find out the time of effluent of Der Chi Resevoir. Furthermore, accordingto the real demand of down stream we manage water resources by level down process. In the theory of multiobjective planning the subject we looked for is how to reach the goals by the limited resources and confliet condition. This model applies to the real operation of Ta-Cha River Basin. The conclusion and suggestion are also presented.