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Auswahl der wissenschaftlichen Literatur zum Thema „Emergency gate closure“
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Zeitschriftenartikel zum Thema "Emergency gate closure"
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Holder, Graham K. „Sault Ste. Marie Lock reconstruction: hydraulic model studies of the stop log emergency closure and lock filling and emptying systems“. Canadian Journal of Civil Engineering 25, Nr. 6 (01.12.1998): 1003–40. http://dx.doi.org/10.1139/l98-033.
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In July 1987, a section of the southwest wall of Sault Ste. Marie Lock failed during a locking operation when a portion of limestone facing, 60 m by 8 m, separated from the rubble backing wall. Engineering investigations resulted in the selection of the Recreational Lock Option, involving either downsizing the lock chamber within the existing lock or constructing a new lock as the most viable solutions. A Dry Dock Option, where the lock would be used to store craft during the winter months, was also considered. However, this option was abandoned during the course of testing. The engineering investigations also revealed that the emergency swing dam, constructed upstream of the existing lock to protect the system should the lock gates be damaged or carried away (as happened in 1909), was in poor condition and required rehabilitation in the order of over $0.5 million. A stop log emergency system was proposed as an alternative safety device designed to stop the flow of water through the canal in the event of gate failure. Physical hydraulic model studies were carried out to evaluate the feasibility of using an emergency stop log system. The tests showed that stop logs constructed with solid horizontal web plates top and bottom result in unacceptably high hydraulic downpull forces. Open truss stop logs can be deployed to stop the flow of water through the canal in the event of gate failure. The follower should also be constructed as an open truss such that the areas of steel exposed to the flow at the top and bottom of the follower are minimized. Hydraulic uplift forces that could prevent closure can be reduced by increasing the space between the stop log and the follower. Physical hydraulic model studies of the lock filling-emptying systems are described. The first and preferred option consists of downsizing the existing lock and retaining part of the existing wooden culverts and emptying system, if possible. A new filling port, filling valves, and supply culvert would be constructed upstream. In the event that the existing wooden culverts are found to be unserviceable, a second option was considered. This second option would be to fill in the wooden culverts and then construct a new filling port, filling valves, and supply culvert that would discharge into the lock through the upstream breast wall just above floor level. The existing emptying system would be retained or rebuilt. The third option, if both the filling and discharge culverts have to be condemned, would be to build a new lock. The results of the hydraulic model studies carried out to explore these three options are described.Key words: emergency closure, stop logs, follower, canal, lock, downpull, uplift, crane capacity, filling-emptying system, culverts.
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Johnson, Michael C., M. Leslie Boyd und Dustin G. Mortensen. „Closure to “Stop Logs for Emergency Spillway Gate Dewatering” by Derek R. Freckleton, Michael C. Johnson, M. Leslie Boyd, and Dustin G. Mortensen“. Journal of Hydraulic Engineering 138, Nr. 6 (Juni 2012): 578. http://dx.doi.org/10.1061/(asce)hy.1943-7900.0000556.
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Yap, Christopher Michael, Youki Kadobayashi und Suguru Yamaguchi. „Conceptualizing Player-Side Emergence in Interactive Games“. International Journal of Gaming and Computer-Mediated Simulations 7, Nr. 3 (Juli 2015): 1–21. http://dx.doi.org/10.4018/ijgcms.2015070101.
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The concept of emergence exists in many fields such as Philosophy, Information Science, and Biology. With respect to the modern video game, emergence can potentially manifest as emergent narrative and/or gameplay. In this paper, the authors engage in a critical discussion about what it means for an interactive video game to have emergence. The authors frame the discussion of emergence as a close critical look at the games Papers, Please and Gone Home. From these analyses, the authors propose a concept of “Player-side emergence in games,” in which emergence in the form of narrative is expressible and observable in games which rely not on the game software itself, but also upon the complex system of the human mind for reconstruction of the game experience and a subsequent expression of emergence. The authors contend that such an emergent design consideration is potentially useful for designers who are trying to address the trade-off of Ludo-Narrative Dissonance.
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Nie, Yan-hua, Ling-min Liao und Guo-bing Huang. „Research on emergency control mode of sluice gates in water delivery canal“. MATEC Web of Conferences 246 (2018): 01005. http://dx.doi.org/10.1051/matecconf/201824601005.
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The regulation of sluice gates（control gates, dividing gates and exit sluices） in water delivery canal is very important and complicated especially in emergency conditions. Most of existing achievements are about canal control theory or based on normal operation condition, lack of researches about emergency joint dispatch under accident conditions and its internal mechanism. In this paper, a mathematical model for emergency dispatch of a long water delivery canal was established to study gate control modes. Some typical operating conditions were selected as study cases and some indicators which could affect safety and economical efficiency of project operation like water level, return water, gate action times were selected as measuring indices. The simulation calculations about different gate control modes of control gates and exit sluices（control speed, open and close time, action frequency, etc）were carried out, through changing gate group control modes to simulate disturbances in emergency regulating process, then track the unsteady flow hydraulic response of channel, analyze the variation of hydraulic parameter, ascertain the relationship between disturbances and channel hydraulic response, summarize the induction mechanism at last. The results can enrich canal gate emergency control theory and improve operation safety and economical efficiency. They can also provide scientific guidances for operation of water diversion projects to enhance emergency disposal ability, and it has strong academic and practical value.
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Kong, Lingzhong, Xiaohui Lei, Qian Yang, Hezhen zheng und Hao Wang. „Automatic feedback control algorithm for canal for a quick upstream water supply interruption in the case of an emergency“. MATEC Web of Conferences 246 (2018): 02026. http://dx.doi.org/10.1051/matecconf/201824602026.
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For the sudden upstream water interruption in the canal of an emergency, the existing research method guiding gate control is mainly feed-forward compensation algorithm, under which algorithm the interruption of water diversions is the upstream first and then the downstream. In order to achieve a more flexible water demand for different water diversions purpose, this study used PI water level difference feedback control algorithm to control the gate under this condition. The research results showed that the PI water level difference feedback control algorithm can make the change trend of water level of multi-pool close and reduce the rate of water level decline, and thus prolong the continuous delivery time of pools with offtake delivery demand under sudden upstream water interruption. Moreover, the PI water level difference method has good robustness and can be applied to more complex combinations of inflow and delivery changes. This study provides another way of thinking for the regulation of the gate in the case of sudden upstream water interruption.
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Koken, Mete, Ismail Aydin und Akis Sahin. „Application of computational fluid dynamics to predict hydrodynamic downpull on high head gates“. Engineering Computations 34, Nr. 4 (12.06.2017): 1191–203. http://dx.doi.org/10.1108/ec-04-2016-0137.
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Purpose High head gates are commonly used in hydropower plants for flow regulation and emergence closure. Hydrodynamic downpull can be a critical parameter in design of the lifting mechanism. The purpose of this paper is to show that a simplified two-dimensional (2D) computational fluid dynamics solution can be used in the prediction of the downpull force on the gate lip by comparison of computed results to experimentally measured data. Design/methodology/approach In this study, ANSYS FLUENT CFD software was used to obtain 2D numerical solution for the flow field around a generic gate model located in a power intake structure which was previously used in an experimental study. Description of the flow domain, computational grid resolution, requirements on setting appropriate boundary conditions and methodology in describing downpull coefficient are discussed. Total number of 245 simulations for variable gate lip geometry and gate openings were run. The downpull coefficient evaluated from the computed pressure field as function of gate opening and lip angle are compared with the experimental results. Findings The computed downpull coefficient agrees well with the previous experimental results, except one gate with small lip angle where a separation bubble forms along the lip, which is responsible from this deviation. It is observed that three-dimensional (3D) effects are confined to the large gate openings where downpull is minimum or even reversed. Research limitations/implications In large gate openings, three dimensionality of the flow around gate slots plays an important role and departure from 2D solutions become more pronounced. In that case, one might need to perform a 3D solution instead. Practical implications This paper presents a very fast and accurate way to predict downpull force on high head gates in the absence of experimental data. Originality/value An extensive amount of simulations are run within the scope of this study. It is shown that knowing its limitations, 2D numerical models can be used to calculate downpull for a wide range of gate openings without the need of expensive experimental models.
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Fanani, Ahwan. „Al-Suyutî Dan Kontroversi Strata Ijtihâd: Telaah atas Klaim Mujtahid Mutlaq al-Suyutî dan Landasan Normatifnya“. ISLAMICA: Jurnal Studi Keislaman 2, Nr. 2 (22.01.2014): 109. http://dx.doi.org/10.15642/islamica.2008.2.2.109-123.
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<p><em>The 6</em><em>th </em><em>century of Islam witnessed the first emergence of the new class of ‘ulama that tended to “close” the gate of ijtihad. By the closure of the gate of ijtihad I do not mean that the gate of ijtihad can indeed be closed. At some point of its development, the legal system of various schools of thought of Islam has finally been established, the resultant consequence of which being that some ‘ulama felt that ijtihad can only be done on elaborating further the views of the previous ‘ulama and not on proposing original views on particular legal issue of Islam. Al-Suyuti emerged during the era where legal system of Islam has already been established. He claims interestingly, that he is a mujtahid mutlaq, that is, some one who has the absolute and independent authority to do ijtihad and to extrapolate rules from the legal sources of Islam. This comes as a sharp contrast to the general belief at the time that no mujtahid mutlaq may any longer emerge. Al-Suyuti wrote al-Radd to legitimize his claim; a claim that inevitably prompted a strong</em></p><em>objection from his fellow legalists. Although his claim was not received with enthusiasm from the public, al-Suyuti has nonetheless made a valuable contribution in the field of the study of ijtihad. His works are applauded as a great evaluation on the subject. On various occasions, al-Suyuti wrote that the Muslim intellectuals should not be satisfied with the views of the previous ‘ulama (taqlid) and that they should instead exercise their intellectual acumen via ijtihad.</em>
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Faurot-Daniels, Ellen R., Julie T. Yamamoto, Randy H. Imai und Susan A. Klasing. „California Marine Oil Spill Fisheries Closure: Key Processes of the Department of Fish and Game (DFG), Office of Spill Prevention and Response (OSPR), During a Fisheries Closure Event“. International Oil Spill Conference Proceedings 2011, Nr. 1 (01.03.2011): abs101. http://dx.doi.org/10.7901/2169-3358-2011-1-101.
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ABSTRACT Determining whether to close a commercial, recreational, or subsistence fishery after an oil spill is a difficult emergency decision that must be made quickly by California state authorities. California state law now states that fisheries affected by a spill must be closed within 24 hours of a spill of one barrel (42 gallons) or more of oil, unless it can be determined that the actual risk is non-existent or has been mitigated. However, assessing the amount of oil truly spilled, the status of spilled oil containment versus spreading rate, and determining which fisheries are in the potential path of oil are all confounding factors. While the goal of the law is to protect people from consuming fish or shellfish that exceed established petroleum contaminant thresholds, caution is used to make sure fisheries are not closed unnecessarily. The California fishery closure protocol articulates the separate, specific, and coordinated roles and responsibilities of the Department of Fish and Game (DFG) and the Office of Environmental Health Hazard Assessment (OEHHA). These protocols are internal to the two involved California state agencies, and are separate from any fishery closure decisions that might be made by the National Marine Fisheries Service for spills in federal waters.
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Zhang, Zi-Xin, Liang Wang und Ying-Ming Wang. „An Emergency Decision Making Method for Different Situation Response Based on Game Theory and Prospect Theory“. Symmetry 10, Nr. 10 (11.10.2018): 476. http://dx.doi.org/10.3390/sym10100476.
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Because of the continuous burst of emergency events (EEs) recently, emergency decision making (EDM) has become an active research topic due to its crucial role in relieving and reducing various losses and damages (property, lives, environment, etc.) caused by EEs. Current EDM studies based on prospect theory (PT) have considered decision maker’s (DM’s) psychological behavior, which is very important in the EDM process because it affects DM’s decision behavior directly, particularly under the uncertainty decision environment. However, those studies neglected an important fact that different emergency situations should be handled by different measures to show the pertinence and effectiveness of the emergency response in the real world, which has been taken into consideration in EDM studies based on game theory (GT). Different behavior experiments show that DMs usually have limited rationality when involved in risk and an uncertain decision environment, in which their psychological behavior has distinct impacts on their decision choice and behavior. Nevertheless, the existing studies of EDM based on GT build on an assumption that DMs are totally rational; however, it is obvious that such an assumption is unreasonable and far from the real-world situation. Motivated by these limitations pointed out previously, this study proposes a novel EDM method combining GT and PT that considers not only the DM’s psychological behavior, but also takes different situations’ handling for EEs into account, which is closer to the EDM problems in reality. An example and comparison with other methods are provided to demonstrate the validity and rationality of the proposed method for coping with real-world EDM problems.
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Brusotti, Marco. „“What belongs to a language game is a whole culture.”“. Wittgenstein-Studien 9, Nr. 1 (21.02.2018): 51–73. http://dx.doi.org/10.1515/witt-2018-0005.
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Abstract:Wittgenstein remarks that “What belongs to a language game is a whole culture”, and that describing the language games in which the “words we call expressions of aesthetic judgement” are used implies describing “the culture of a period” (LA 1966: 8). Without aiming at a full reconstruction, the paper addresses the gradual emergence of the close conceptual connection between “language game” and “culture” in Wittgenstein’s manuscripts. The apparently obvious idea that “language game” and “form of life” (or “culture”) belong together or even coincide was originally missing. The paper picks out few episodes from Wittgenstein’s philosophical development. The first chapter shows that the topic of cultural diversity emerges in Wittgenstein’s reception of Oswald Spengler’s The Decline of the West, but still plays only a limited role in his first criticism of James Frazer’s The Golden Bough. The second chapter discusses the emergence of the term “language game” and establishes that Wittgenstein’s first language games do not yet imply something like an “anthropological view”. Real and imaginary “peoples” and “tribes” make their first appearance in remarks that ascribe a “primitive” arithmetic to them (chapter 3). Finally, with an eye to the possible influence of Sraffa and Malinowski, the fourth section shows how the Brown Book conceives translation as holistic cultural comparison.
Dissertationen zum Thema "Emergency gate closure"
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Pulle, Doreen. „Investigation of the sudden air release up the airshaft of the Berg river dam bottom outlet structure during emergency gate closure using numerical modelling methods“. Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/17798.
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Thesis (MScEng)--Stellenbosch University, 2011.ENGLISH ABSTRACT: The design of the Berg River Dam bottom outlet structure with multitude draw offs was based on various hydraulic model tests on a 1:40 model that was used for original design and a 1 in 20 physical model which was used to produce the final design. These tests indicated no foreseeable malfunction and showed that the 1.8 m² air vent would provide sufficient air flow to minimize the negative pressures that would develop behind the emergency gate during its closure or opening. However, during the first trial commissioning of the dam outlet structure, air was unexpectedly expelled through the air vent at a velocity so high that the recta-grids covering the shaft were blown to a height of over 3m while the gate was closing at a rate of approximately 0.0035 m/s. The air flow velocity up the air vent was approximately 45m/s and occurred when the gate was approximately 78% closed. A brief report on the test indicated that the source of air may have been a vortex formation in the vertical intake tower upstream of the emergency gate entraining air which was drawn through the gate and released up the air vent. The purpose of this research was to utilize 3-dimensional numerical modelling employing Computational Fluid Dynamics (CFD) to carry out numerical simulations to investigate the above mentioned malfunction and thereby establishing whether the given hypotheses for the malfunction were valid. For purposes of validating the CFD modelling, a 1:14.066 physical model was constructed at the University of Stellenbosch hydraulics laboratory. The 3-dimensional CFD model was used to investigate the said incident, using steady state simulations that were run for various openings of the emergency gate. The intenetion was to establish whether there was an emergency gate opening which would reproduce the air release phenomenon. The results obtained from the numerical model showed a similar trend to those of the physical model although there were differences in values. Neither model, showed a sudden release of air through the vent. It was concluded that the unsteady air-water flow out of the air vent may have been caused by the variation of the discharge with time causing unbalanced negative pressures in the outlet structure. Therefore, it was recommended that further CFD transient simulations should be undertaken incorporating a moving emergency gate.
AFRIKAANSE OPSOMMING: Die ontwerp van die bodemuitlaat van die Bergrivierdam met multivlakuitlate is gebaseer op verskeie hidrouliese modeltoetse op a 1:40 fisiese model wat vir die oorspronklike ontwerp gebruik is, asook „n 1 tot 20 fisisiese model wat gebruik is om die finale ontwerp te lewer in 2003. Hierdie toetse het geen beduidende afwykings aangedui nie en het bewys dat die 1.8mª lugskag voldoende lugvloei sal toevoer om die negatiewe drukking wat stroomaf van die noodsluis ontstaan gedurende die sluitingsproses, sal minimaliseer. Gedurende die inlywingtoets in die veld in 2008 van die noodsluis, is lug onverwags teen 'n hoë snelheid deur die lugskag opwaarts uitgelaat, wat die rooster wat die skag beskerm teen 'n hoogte van oor 3m geblaas het terwyl die sluis teen 'n tempo van ongeveer 0.0035 m/s toegemaak het. Die lugvloeisnelheid in die lugskag was ongeveer 45m/s en het plaasgevind toe die sluis ongeveer 78% toe was. 'n Kort verslag oor die veldtoets dui aan dat die bron van die lug dalk werwelvorming in die vertikale inlaattoring stroomop van die noodsluis was, met lug wat deur die sluis getrek was en opwaarts in die lugskag vrygelaat is. Die doel van die navorsing was om drie-dimensionele numeriese modellering met rekenaar vloeidinamika (RVD) te benut om numeriese similasies uit te voer om die bogenoemde abnormale werking van die lugskag te ondersoek en daarmee vas te stel of die gegewe aannames van krag is. Vir die doel om die RVD modellering te verifieer is 'n 1:14.066 fisiese model gebou by die Universiteit van Stellenbosch se waterlaboratorium. Die 3-dimensionele RVD model is gebruik om die genoemde probleem te ondersoek, deur stasionêre simulasies wat vir verskillende openinge van die noodsluis geloop is te gebruik. Die doel was om vas te stel of daar 'n spesifieke noodsluisopening is wat die vrylating van die lug veroorsaak het. Die uitslag verkry deur die numeriese model het dieselfde windrigting soos die van die fisiese model gewys, alhoewel daar verskille in die waardes was. Nie een van die modelle het .n skielike vrystelling van lug deur die lugskag gewys nie. 'n Afleiding is gemaak dat die nie stasionêre lug-water vloei uit die lugskag moontlik veroorsaak was deur die verandering van die vloei met tyd veroorsaak deur ongebalanseerde negatiewe druk in die uitlaatstruktuur. Daarom is daar voorgestel dat verdere RVD nie stasionêre simulasies gedoen word met 'n bewegende noodsluis.
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Málek, Miroslav. „Nestacionární CFD simulace toku uzavírajícím se tabulovým uzávěrem“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-444633.
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Emergency gates are important safety feature of hydropower plants. They are used to close the flow in order to protect power plant equipment in case of emergency. In this diploma the-sis are realized CDF simulations of emergency closure of wheel-mounted gate on two-dimensional model of the Slapy hydropower plant. Simulations were performed for the case of constant lowering gate speed and for the case of gravitational closure. Dynamic mesh was used to enable the gate motion. The 6DOF method was used for the case of gravitational clo-sure and user defined function was defined to control movement of the gate. User defined function include gravitational force, hydrodynamic forces and friction force. Simulations were used to verify forces acting on gate and volume flow through gate during closing process. In case of gravitational closure the speed and orientation of closing process and closing process time were determined.
Bücher zum Thema "Emergency gate closure"
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United States. Bureau of Reclamation., Hrsg. Emergency closures of guard gates with unbalanced heads: High-pressure slide gates. Denver, Colo: U.S. Bureau of Reclamation, 1993.
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Piecka, Debra C. Burkey, und Manetta Calinger. „Using a Live Simulation to Teach Human Anatomy and the Diagnostic Process to High School Students“. In Advances in Game-Based Learning, 307–25. IGI Global, 2016. http://dx.doi.org/10.4018/978-1-4666-9629-7.ch015.
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This chapter describes and defines role-play simulations. Reviews of two undergraduate role-play studies highlight the advantages and benefits of using simulations. Few secondary students participate in science or STEM role-plays during their high school careers. This chapter portrays the CyberSurgeons live simulation where teams of students use critical thinking skills and scientific knowledge to solve emergency medical problems. During their virtual mission students become part of an emergency medical team aboard a National Institutes of Health (NIH) mercy ship traveling up the Amazon River. Authors describe CyberSurgeons' learning goals, design features, mission day experiences, and the summative evaluation. Findings from the summative evaluation indicate that the CyberSurgeons program provides an authentic context for high school students to apply their knowledge of biology, physiology, and the diagnostic process to analyze data and make decisions as professionals in the biomedical field. Recommendations and future research considerations close this chapter.
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Davies, Peter N. „A Guide to the Emergence of Japan's Modern Shipping Industries“. In International Merchant Shipping in the Nineteenth and Twentieth Centuries. Liverpool University Press, 2008. http://dx.doi.org/10.5949/liverpool/9780973893472.003.0004.
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This essay explores the development of Japanese shipping, which grew at a considerable rate to become the second largest fleet in the world as of the year 2000. Peter N. Davies considers the unique relationship between the Japanese government and Japanese shipowners, exploring the historical factors that developed this relationship and the way governmental policy provided comparative advantages for Japanese ship-owning companies. He also explores the benefits of the close relationship between shipowners and shipbuilders. Unlike Norway and Greece, Japan found great success with passenger liners. Davies concludes that skill and application gave Japan the competitive edge in the international shipping market, and that this success is likely to continue in the future.
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Hillewaert, Sarah. „Senses of Morality and Morality of the Senses“. In Morality at the Margins, 191–232. Fordham University Press, 2019. http://dx.doi.org/10.5422/fordham/9780823286515.003.0009.
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Non-verbal communication, while never separate from verbal communication, has a distinct signifying value in the context of Lamu. Because the exchange of verbal greetings carries implications for an individual’s respectability, individuals frequently rely on non-verbal language to communicate while in public. Chapter Five therefore looks at how material practices and the moving body are implicated in the negotiation of social change and the emergence of new social positionings. It examines how young men and women in Lamu differently use material and bodily practices—e.g. stride, walking route, hand greetings, gaze, clothing—to gradually redefine norms of proper conduct and social status. A closer look at young women’s use of handshakes, the ethnographic vignette of a young female professional accused of immoral conduct, and the story of a beach boy who becomes a local politician illustrate the different means through which young people negotiate a respectful positions within the Lamu community. The theoretical discussion in this chapter focuses on gender, material practice, and the moving body in relation to ideologies of moral personhood and notions of modernity.
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Hallam, Tony. „The evolutionary significance of mass extinctions“. In Catastrophes and Lesser Calamities. Oxford University Press, 2004. http://dx.doi.org/10.1093/oso/9780198524977.003.0013.
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Darwin was firmly of the opinion that biotic interactions, such as competition for food and space – the ‘struggle for existence’ – were of considerably greater importance in promoting evolution and extinction than changes in the physical environment. This is clearly brought out by this quotation from The Origin of Species: . . . Species are produced and exterminated by slowly acting causes . . . and the most important of all causes of organic change is one that is almost independent of altered . . . physical conditions, namely the mutual relation of organism to organism – the improvement of one organism entailing the improvement or extermination of others. . . . The driving force of competition in a crowded world is also stressed in another quotation presenting Darwin’s famous wedge metaphor: . . . In looking at Nature, it is most necessary . . . never to forget that every single organic being around us may be said to be striving to the utmost to increase in numbers; that each lives by a struggle at some period of its life; that heavy destruction inevitably falls either on the young or the old, during each generation . . . The face of Nature may be compared to a yielding surface, with ten thousand sharp wedges packed close together and driven inwards by incessant blows, sometimes one wedge being struck, and then another with greater force. . . . The implication of the Darwinian view concerning the dominance of biotic competition is that for each winner there is a loser – a kind of zero-sum game. It has been accepted more or less uncritically by generations of evolutionary biologists, but not until the 1970s did it become graced with a name – the Red Queen hypothesis. The story behind the emergence of this name is an interesting one. At the beginning of the 1970s the rather eccentric University of Chicago palaeobiologist Leigh Van Valen did some interesting research concerning the analysis of survivors of Phanerozoic taxa which suggested that the probability of a fossil group becoming extinct was more or less constant in time. To account for this, Van Valen put forward his Red Queen hypothesis.
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Mitchell, Peter. „The Triumph of the Mule“. In The Donkey in Human History. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198749233.003.0012.
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This chapter starts as the Roman Empire fragmented, encompasses the emergence of Christianity and Islam, and explores the donkey’s place in the history of the Middle Ages, as well as what Fernand Braudel termed ‘the triumph of the mule’ in the ensuing early modern period from the fifteenth to the nineteenth centuries. Being closer in time to the present, historical documents are generally richer and more plentiful than for earlier periods, but archaeological excavations and surveys—especially of post-medieval sites and landscapes—are still undeveloped in many regions. Inevitably, therefore, what I present draws as much on textual sources as it does on them. I look first at the symbolic value of donkeys and mules in Christianity and Islam. Next, I consider their disappearance from some parts of Europe in the aftermath of Rome’s collapse and their re-expansion and persistence elsewhere. One aspect of this concerns their continuing contribution to agricultural production, another their consumption as food, a very un-Roman practice. A second theme showing continuities from previous centuries is their significance in facilitating trade and communication over both short and long distances. Tackling this requires inserting donkeys and mules into debates about how far pack animals replaced wheeled forms of transport as Late Antiquity gave way to the Middle Ages. Wide-ranging in time and space, this discussion also provides opportunities for exploring their role in human history in areas beyond those on which I have concentrated thus far. West Africa is one, the Silk Road networks linking China to Central Asia a second, and China’s southward connections into Southeast Asia a third. According to the New Testament Jesus entered Jerusalem on Palm Sunday seated on a donkey (Plate 20). The seventh-century apocryphal Gospel of Pseudo-Matthew also envisages donkeys carrying His mother to Bethlehem, being present at the Nativity, and conveying the Holy Family into temporary exile in Egypt. Donkeys thus framed both ends of Jesus’ life and, given their importance in moving people and goods in first-century Palestine, must have been a familiar sight. But the implications of their place in Christianity’s narrative were originally quite different from those that are generally understood today.
Konferenzberichte zum Thema "Emergency gate closure"
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Schohl, Gerald A. „Transient Analyses for Great Falls Hydro Plant“. In ASME/JSME 2003 4th Joint Fluids Summer Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/fedsm2003-45258.
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Transient analyses provide estimates of maximum pressure in the Great Falls Unit 1 penstock following load rejection. Additional transient analyses, along with hydrodynamic force and moment coefficients, provide estimates of unsteady loads on the Unit 1 emergency butterfly valve during closure. Position varying force and moment coefficients for a butterfly valve were determined by CFD modeling. A new method for representing turbine and pump-turbine characteristics that involves a slight modification to the standard Suter representation permits linear interpolation between the discrete curves representing data at different wicket gate openings.
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Everline, Chester, Gregory Gromov, Igor Lola, Stanislav Sholomitsky, Victor Mukoid, Steve Meyer und Alexander Sevbo. „Assessment of Potential Negative Impacts of the Main Gate Valve Closure Under Loss of Coolant Accident at VVER-440 Model 213 Nuclear Power Plant“. In 12th International Conference on Nuclear Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/icone12-49342.
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The paper presents the results of the special screening assessment, conducted under the Level 1 Probabilistic Risk Assessment (PRA) study for the Rivne Nuclear Power Plant (RNPP) Unit 1, Ukraine. This analysis has been intended to investigate potential for negative impacts of the closure of the Main Gate Valves (MGV) during loss of coolant accident (LOCA). RNPP Unit 1 is a VVER-440 Model 213 plant featuring six operating primary loops with MGVs installed at the hot and cold legs of each loop. Emergency operating instructions (EOIs) direct operators to isolate a leaking primary loop using the MGVs during a LOCA. From the experience of accident analyses for some Westinghouse plants it is known that closing loop stop valves (LSV, which are analogous to the VVER-440 MGVs) during accidents may result in more severe consequences. In particular, closing a LSV (or MGV) during a LOCA could inhibit steam venting through the break, and thus depress core levels. This would hasten the onset of core damage. Considering this experience, there has been a need to address such potential impacts in the RNPP Unit 1 PRA, taking into account design specifics of the VVER-440/213 plants. The analysis, which has combined qualitative considerations and thermal-hydraulic calculations with RELAP5/Mod3.2 model of the RNPP Unit 1 nuclear steam supply system, has revealed that such impacts are unimportant for this plant. The paper presents the approach and results of the assessment, and describes the supporting reactor thermal hydraulic evaluations.
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King, Graeme, Dan Hoang, Victoria Stranzinger und David Thom. „Hot Bitumen Pipeline Valve Replacement: Pipe Prop Anchoring Design With Mechanical Tensioning“. In 2020 13th International Pipeline Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/ipc2020-9391.
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Abstract An NPS 24 inline gate valve on a buried hot bitumen pipeline operating at temperatures up to 149°C failed open. The valve is on the north bank of the Steepbank River in northern Alberta and is equipped with an actuator that can automatically close the valve to protect the river in case of an emergency. It was therefore important to replace the valve as soon as practical. Worley was engaged to provide detailed engineering services for replacing the valve. Engineering objectives covered safety concerns associated with high operating temperatures and large axial compressive force in the pipeline, minimization of downtime, development of the best long-term valve replacement solution, and return of the pipeline to service with the same resistance to upheaval buckling it had when it was originally designed and constructed. Because the pipeline is buried and therefore restrained by the surrounding soil, an important goal of the original design was to prevent upheaval buckling and possible loss of containment by controlling thermal expansion forces due to its high operating temperature. Control was achieved during the original construction in two ways. Firstly, thermal compressive forces were reduced by heating the line to 90°C with forced air and locking it into the surrounding soil in its expanded state, and secondly, restraint was increased by using good backfill compaction, increased depth of burial, and imported fill wherever necessary. The high axial compressive force on the inline buried valve was identified as a possible cause of failure, and an early decision was made to replace it using an aboveground valve with sufficiently flexible aboveground piping to minimize or eliminate compressive forces on the valve. When the pipeline was cooled and cut to install the new valve, the original prestress was released, and the cut ends of the pipe pulled back on either side of the valve. The lost prestress was reinstated to the level specified in the original design using an innovative custom designed load bearing strut and tensioning system, referred to here as a Pipe Prop, that was installed between the cut ends of the buried mainline after the failed valve and fittings had been removed. The Pipe Prop also prevented differential axial movement between the cut ends of the buried pipeline due to changes in the operating pressure and temperature. This reduced the need for flexibility in the aboveground piping and allowed a short offset to be used between the new valve and the buried mainline, which reduced the footprint of the aboveground piping enough to fit within the restrictive boundaries of the site. Strain gauges were installed on the pipeline adjacent to the failed valve and upstream and downstream of the valve site. The gauges measured changes in stress when the buried pipeline was first cut, and allowed the stress state of the buried pipeline to be calculated to find if the cause of failure had been large axial loads imposed on the valve by the pipeline. The strain gauges also measured strain in the buried pipeline while using the tensioning system built into the Pipe Prop to re-establish the design level of prestress. Permanent strain gauges were also installed on the new aboveground piping adjacent to the replacement valve. The pipeline was returned to hotbit service in August 2019 and has operated continuously since that time without further problems at the valve station.
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Moussafir, J., C. Olry, M. Nibart, A. Albergel, P. Armand, C. Duchenne, F. Mahé, L. Thobois, S. Loaëc und O. Oldrini. „AIRCITY: A Very High Resolution Atmospheric Dispersion Modeling System for Paris“. In ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting collocated with the ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/fedsm2014-21820.
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The AIRCITY project, partly funded by the European Union, is now successfully achieved. It aimed at developing a 4D innovative numerical simulation tool dedicated to the dispersion of traffic-induced air pollution at local scale on the whole urban area of PARIS. AIRCITY modeling system is based on PMSS (Parallel-Micro-SWIFT-SPRAY) software, which has been developed by ARIA Technologies in close collaboration with CEA and MOKILI. PMSS is a simplified CFD solution which is an alternative to micro-scale simulations usually carried out with full-CFD. Yet, AIRCITY challenge was to model the flow and pollutant dispersion with a 3 m resolution over the whole city of Paris covering a 14 km × 11,5 km domain. Thus, the choice was to run a mass-consistent diagnostic flow model (SWIFT) associated with a Lagrangian Particle Dispersion Model (SPRAY) on a massively parallel architecture. With a 3 m resolution on this huge domain, parallelization was applied to the computation of both the flow (by domain splitting) and the Lagrangian dispersion (management of particles is split over several processors). This MPI parallelization is more complex but gives a large flexibility to optimize the number of CPU, the available RAM and the CPU time. So, it makes possible to process arbitrarily large domains (only limited by the memory of the available nodes). As CEA operates the largest computing center in Europe, with parallel machines ranging from a few hundred to several thousand cores, the modeling system was tested on huge parallel clusters. More usual and affordable computers with a few tens of cores were also utilized during the project by ARIA Technologies and by AIRPARIF, the Regional Air Quality Management Board of Paris region, whose role was also to build the end-users requirements. These computations were performed on a simulation domain restricted to the hypercenter of Paris with dimensions around 2 km × 2 km (at the same resolution of 3 m). The focus was on the improvements needed to adapt simulation codes initially designed for emergency response to urban air quality applications: • Coupling with the MM5 / CHIMERE operational photochemical model at AIRPARIF (as the forecast background), • Turbulence generated by traffic / coupling with traffic model, • Inclusion of chemical reactions / Interaction with background substances (especially NO / NO2). Finally, in-depth validation of the modeling system was undertaken using both the routine air quality measurements in Paris (at four stations influenced by the road traffic) and a field experiment specially arranged for the project, with LIDARs provided by LEOSPHERE Inc. Comparison of PMSS and measurements gave excellent results concerning NO / NO2 and PM10 hourly concentrations for a monthly period of time while the LIDAR campaign results were also promising. In the paper, more details are given regarding the modeling system principles and developments and its validation. Perspectives of the project will also be discussed as AIRCITY system. The TRL must now be elevated from a demonstration to a robust and systematically validated modeling tool that could be used to predict routinely the air quality in Paris and in other large cities around the world.