Academic literature on the topic 'Limit state flexibility'
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Journal articles on the topic "Limit state flexibility"
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Hu, Wen, and Jessica B. Cicchino. "Lowering the speed limit from 30 mph to 25 mph in Boston: effects on vehicle speeds." Injury Prevention 26, no. 2 (January 13, 2019): 99–102. http://dx.doi.org/10.1136/injuryprev-2018-043025.
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IntroductionEffective 9 January 2017, the default speed limit on Boston streets was reduced from 30 mph to 25 mph. This study evaluated the effects of the speed limit reduction on speeds in Boston.MethodVehicle speeds were collected at sites in Boston where the speed limit was lowered, and at control sites in Providence, Rhode Island, where the speed limit remained unchanged, before and after the speed limit change in Boston. A log-linear regression model estimated the change in vehicle speeds associated with the speed limit reduction. Separate logistic regression models estimated changes in the odds of vehicles exceeding 25 mph, 30 mph and 35 mph associated with the lower speed limit.ResultsThe speed limit reduction was associated with a 0.3 % reduction in mean speeds (p=0.065), and reductions of 2.9%, 8.5% and 29.3 % in the odds of vehicles exceeding 25 mph, 30 mph and 35 mph, respectively. All these reductions were statistically significant.ConclusionsLocal communities should consider lowering speed limits to reduce speeds and improve safety for all road users. The current practice of setting speed limits according to the 85th percentile free-flow speeds, without consideration of other characteristics of the roadway, can be a hurdle for local communities looking to lower speed limits. Updated state laws that allow municipalities to set lower speed limits on urban streets without requiring costly engineering studies can provide flexibility to municipalities to set speed limits that are safe for all road users.
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Liu, Hanbing, Xin He, Yubo Jiao, and Xirui Wang. "Reliability Assessment of Deflection Limit State of a Simply Supported Bridge using vibration data and Dynamic Bayesian Network Inference." Sensors 19, no. 4 (February 18, 2019): 837. http://dx.doi.org/10.3390/s19040837.
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Structural health monitoring (SHM) has been widely used in all kinds of bridges. It is significant to accurately assess the serviceability and reliability of bridge subjected to severe conditions by SHM technique. Bridge deflection as an essential evaluation index can reflect structural condition perfectly. In this study, an approach for deflection calculation and reliability assessment of simply supported bridge is presented. Firstly, a bridge deflection calculation method is proposed based on modal flexibility and Kriging method improved by artificial bee colony algorithm. Secondly, a dynamic Bayesian network is employed to evaluate the deflection reliability combined with monitoring results which include modal frequency, mode shape, environmental temperature, and humidity. A linear regression model is established to analyze the relationship between modal parameters and environmental factors. Thirdly, a simply supported bridge is constructed and monitored to verify the effectiveness of the proposed method. The results reveal that the proposed method can precisely calculate the bridge deflection. Finally, the time-dependent reliabilities of two cases are computed and the effects of monitoring factors on bridge deflection reliability are analyzed by sensitivity parameter. It indicates that the reliability is negatively correlated with temperature and more sensitive to mode shape than other three factors.
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Zhao, Xin, Wei Ping Zhao, and Song Xiang. "Controller Optimization of Quadrotor UAV." Applied Mechanics and Materials 709 (December 2014): 237–40. http://dx.doi.org/10.4028/www.scientific.net/amm.709.237.
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Adjusting method of traditional PID controller is complicated. The controller obtained by adjusting method of traditional PID may be not optimal. Therefore, present paper utilized the genetic algorithm to optimize the PID controller parameter of roll channel of quadrotor UAV. According to the feature of lateral stability control model of quadrotor UAV, ascend time of system, steady state error, and weighted overshoot are chosen as objective function. In order to obtain the better control effect, penalty function is used to limit the oscillation of system. Simulation results show that PID controller designed by the genetic algorithm possess the excellent flexibility, adaptability and can produce the better control effect.
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Stianson, J. R., D. G. Fredlund, and D. Chan. "Three-dimensional slope stability based on stresses from a stress-deformation analysis." Canadian Geotechnical Journal 48, no. 6 (June 2011): 891–904. http://dx.doi.org/10.1139/t11-006.
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A procedure is developed where stresses from a finite element analysis are incorporated into a limit equilibrium framework to evaluate the stability of three-dimensional slopes. An independent stress-deformation analysis is performed to calculate the internal stress state for the slope. The stress distribution is imported into the three-dimensional slope stability analysis in the form of a regular grid. The slip surfaces considered in the limit equilibrium analysis are ellipsoidal and discretized using a series of triangular planes. The normal and shear force acting at the centroid of individual triangular planes can be computed from the internal stress distribution. Subsequently, the factor of safety of a selected slip surface can be calculated directly without using an iterative procedure. A series of verification examples are presented to confirm that the proposed method provides the required accuracy and flexibility to assess the stability of slopes typically encountered in practice. Sensitivity analyses are presented to show how the procedure used to compute the forces acting on each triangular plane, the number of planes used to discretize the slip surface, and Poisson’s ratio influence the computed factors of safety, but do not limit the successful application of the methodology.
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Lima, Jacob Carlos, and Aline Suelen Pires. "YOUTH AND THE NEW CULTURE OF WORK: CONSIDERATIONS DRAWN FROM DIGITAL WORK." Sociologia & Antropologia 7, no. 3 (September 2017): 773–97. http://dx.doi.org/10.1590/2238-38752017v735.
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Abstract This article discusses how the "new culture of work," which is characterized by the entrepreneurial discourse of flexible work and the demand that workers be mobile, adaptable, creative, innovative, autonomous and self-entrepreneurs, among other subjective attributes, holds "young people" as its ideal model. "Generation Y," as presented by business literature and media, embodies all the "qualities" that companies deem to be desirable in a worker whose flexibility is pushed to the limit. Based on research with Information Technology (IT) professionals in the state of São Paulo, we try to demonstrate that the construction of a positive ideal of creative and innovative youth obscures the intense nature of the work with these technologies, defined by "projectification" and instability.
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Ubertini, F., F. Comodini, A. Fulco, and M. Mezzi. "A Simplified Parametric Study on Occupant Comfort Conditions in Base Isolated Buildings under Wind Loading." Advances in Civil Engineering 2017 (2017): 1–13. http://dx.doi.org/10.1155/2017/3524975.
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Vibrations in buildings can cause occupant discomfort in the form of annoyance, headache, or sickness. While occupant comfort is considered in international standards regarding the design of high rise buildings against wind loading, it is neglected in the design of buildings with seismic protective base isolation systems. Nevertheless, due to their low flexibility, base isolated buildings can be prone to wind-induced vibrations, which makes occupant discomfort a potentially significant serviceability limit state. This paper presents a study on occupant comfort conditions in wind-excited base isolated buildings. A numerical simplified parametric procedure is proposed in order to evaluate the return period of wind events causing human discomfort. A parametric investigation is then presented to evaluate the effects of salient parameters on comfort conditions. The procedure is based on (i) the nonlinear dynamic analysis of the structure modeled as a single-degree-of-freedom oscillator with hysteretic base isolators, (ii) the digital generation of time histories of turbulent wind velocity, and (iii) comfort evaluations based on international standards. Results demonstrate that discomfort conditions can occur a few times in a year, depending upon the wind-exposure of the site, what suggests considering this serviceability limit state in the design of base isolated buildings.
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Hermann, Daniel, Manfred Wirsum, Douglas Robinson, and Philipp Jenny. "Operating Range Extension of an Open Impeller Centrifugal Compressor Stage Utilising 3D Diffuser End Wall Contouring." International Journal of Turbomachinery, Propulsion and Power 5, no. 1 (February 7, 2020): 4. http://dx.doi.org/10.3390/ijtpp5010004.
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State-of-the-art centrifugal compressor units utilised in pipeline and in energy storage applications face the challenge of flexible and highly efficient operation. Geometric contouring on the hub side near a vaned diffuser affects the flow in a way which increases operational flexibility by delaying the incipience of instability and thereby increases compressor operating range. In the present paper, a hub-side wall contouring is applied within the vaneless space and the vaned diffuser of an open impeller centrifugal compressor stage. The performance characteristic of the novel hub contouring is evaluated in a scale-model test rig and compared against a baseline design. A stable operating range increase of 8% is achieved for the contoured design at Mu 2 = 1.16. 5-hole probe measurements covering a complete diffuser blade-to-blade passage are performed upstream the diffuser and compared both against CFD simulations and against the measurements of the baseline design for an operating point near the stability limit.
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Lan, Peng, Teng Fei Wang, and Nian Li Lu. "Out-of-Plane Stability Analysis for Crane Jib with Single Cable Considering Lateral Flexibility of the Cable Fixed Joint." Applied Mechanics and Materials 685 (October 2014): 240–44. http://dx.doi.org/10.4028/www.scientific.net/amm.685.240.
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The out-of-plane stability of crane jib is studied considering the lateral flexibility of the fixed joint. The analytical expression of the out-of-plane buckling characteristic equation for the crane jib with single cable is obtained by establishing the bending deflection differential equation of jib under the instability critical state with the method of differential equation. The equilibrium equation of the fixed point in the lateral direction is introduced to solve the differential equation besides the boundary conditions. The analytical results obtained agree very well with the finite element method (FEM) results. To consider the lateral flexibility of the cable fixed joint, a dimensionless stiffness coefficient measuring the lateral constraint was introduced to derive the out-of-plane buckling characteristic equation. The degeneration forms of the characteristic equation under the limit cases of zero lateral stiffness, infinite lateral stiffness are further discussed. And the influence of the lateral stiffness of fixed joint on the stability of jib is investigated. It is shown that the increase of the lateral stiffness will significantly improve the buckling load of the crane jib especially when the lateral stiffness is very small.
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Arad, Avigdor D., Fred J. DiMenna, Naketa Thomas, Jacqueline Tamis-Holland, Richard Weil, Allan Geliebter, and Jeanine B. Albu. "High-intensity interval training without weight loss improves exercise but not basal or insulin-induced metabolism in overweight/obese African American women." Journal of Applied Physiology 119, no. 4 (August 15, 2015): 352–62. http://dx.doi.org/10.1152/japplphysiol.00306.2015.
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The purpose of this randomized controlled clinical trial was to determine the effect of a 14-week high-intensity interval training (HIIT) intervention with weight stability on metabolic flexibility, insulin sensitivity, and cardiorespiratory fitness in sedentary, premenopausal, nondiabetic, overweight/obese African American women. Twenty-eight subjects were allocated to one of two groups: HIIT, which performed three sessions per week of four high-intensity cycling intervals, or a control group (CON), which maintained their normal level of physical activity. Diet was controlled for all subjects to ensure weight stability. Pre- and postintervention (pre/post), subjects completed an incremental cycling test to limit of tolerance and, following a 10-day high-fat controlled feeding period, a euglycemic-hyperinsulinemic clamp to determine insulin sensitivity and substrate oxidation. Nine members of HIIT (age, 29 ± 4 yr; body mass, 90.1 ± 13.8 kg) and eleven members of CON (age, 30 ± 7 yr; body mass, 85.5 ± 10.7 kg) completed the study. HIIT experienced an increased limit of tolerance (post, 1,124 ± 202 s; pre, 987 ± 146 s; P < 0.05), gas exchange threshold (post, 1.29 ± 0.34 liters/min; pre, 0.97 ± 0.23 liters/min; P < 0.05), and fat oxidation at the same absolute submaximal work rate compared with CON ( P < 0.05 for group-by-time interaction in all cases). However, changes in peak oxygen consumption (V̇o2peak), insulin sensitivity, free fatty acid suppression during insulin stimulation, and metabolic flexibility were not different in HIIT compared with CON. High-intensity interval training with weight stability increased exercise fat oxidation and tolerance in subjects at risk for diabetic progression, but did not improve insulin sensitivity or fat oxidation in the postabsorptive or insulin-stimulated state.
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Reisert, Michael, Ashish Aphale, and Prabhakar Singh. "Solid Oxide Electrochemical Systems: Material Degradation Processes and Novel Mitigation Approaches." Materials 11, no. 11 (November 2, 2018): 2169. http://dx.doi.org/10.3390/ma11112169.
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Solid oxide electrochemical systems, such as solid oxide fuel cells (SOFC), solid oxide electrolysis cells (SOEC), and oxygen transport membranes (OTM) enable clean and reliable production of energy or fuel for a range of applications, including, but not limited to, residential, commercial, industrial, and grid-support. These systems utilize solid-state ceramic oxides which offer enhanced stability, fuel flexibility, and high energy conversion efficiency throughout operation. However, the nature of system conditions, such as high temperatures, complex redox atmosphere, and presence of volatile reactive species become taxing on solid oxide materials and limit their viability during long-term operation. Ongoing research efforts to identify the material corrosion and degradation phenomena, as well as discover possible mitigation techniques to extend material efficiency and longevity, is the current focus of the research and industrial community. In this review, degradation processes in select solid oxide electrochemical systems, system components, and comprising materials will be discussed. Overall degradation phenomena are presented and certain degradation mechanisms are discussed. State-of-the-art technologies to mitigate or minimize the above-mentioned degradation processes are presented.
Dissertations / Theses on the topic "Limit state flexibility"
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Čoček, Jan. "Konstrukční řešení mechanismu napínací kladky zkušebního zařízení." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231728.
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The aim of this diploma thesis is the design of automatic tensioning device for regulating forces in driving belts of high-pressure pumps under long-term testing, in collaboration with Bosch Diesel s.r.o. in Jihlava. The paper describes the development of the mechatronic device, from the selection of components, going through the design phase of the automatic electronic device, up to mechanical design and prototype execution. An assessment is made of custom device based on the test in real operations and economic benefits for the client are evaluated in the conslusion.
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Nogueira, Leila de Mello Yañez. "Estabilidade versus flexibilidade: a dicotomia necessária à inovação na gestão de recursos humanos em uma organização pública, estatal eestratégica como Bio-Manguinhos / Fiocruz." reponame:Repositório Institucional da FIOCRUZ, 2009. https://www.arca.fiocruz.br/handle/icict/2500.
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Made available in DSpace on 2011-05-04T12:36:29Z (GMT). No. of bitstreams: 0
Previous issue date: 2009Este trabalho propõe analisar o fenômeno da terceirização desenvolvido ao longo das duas últimas décadas em Bio-Manguinhos. Trata-se de um estudo de caso realizado na unidade de produção de vacinas e reagentes para diagnóstico da Fundação Oswaldo Cruz. Inicialmente foi realizado um estudo de cenário, analisando a política de gestão do trabalho desenvolvida pelo Estado brasileiro para as instituições públicas. A seguir, a análise passou a verificar a inserção da Fiocruz nessas políticas, desde a sua criação e no decorrer de vigência de diferentes formas de contratação, alternando da extrema rigidez para a total flexibilidade sempre com foco na gestão do trabalho, e, como essas políticas se refletiram no desempenho de Bio-Manguinhos. Baseado no contexto da conformação do Estado e na análise do desempenho da unidade, o trabalho critica a falta de planejamento e de prospecção dessas políticas, que favoreça a inovação de processos, produtos e procedimentos e o desempenho pleno de uma unidade de produção de insumos para a saúde, tão necessários ao atendimento das necessidades da população brasileira. Critica também, a ausência de um modelo de Estado consolidado que sirva de arcabouço à formulação dessas políticas. Devido às fortes críticas dos órgãos de controle acerca da extrapolação dos limites da terceirização praticada nas últimas duas décadas e à falta de definição clara desses marcos legais, o trabalho apresenta uma metodologia baseada nas atribuições dos cargos do plano de carreiras da Fiocruz e culmina com a apresentação de uma matriz de atribuições passíveis de serem realizadas por contratação indireta. Conclui pela necessidade de convivência de dois quadros de trabalhadores: um permanente formado por servidores, estáveis e de carreira e outro flexível, executado por contratação indireta, de caráter eventual, temporário ou de apoio às atividades relacionadas à missão de Bio-Manguinhos. O trabalho ainda sugere a aplicação da mesma metodologia às demais unidades da Fiocruz e que a instituição afirme, frente aos órgãos de controle, quais atividades que ela precisa manter no quadro de servidores permanente e quais ela quer delegar a terceiros sem contudo, ferir a legislação vigente. Por fim, constata-se que a metodologia apresentada ameniza, mas não resolve o problema, dessa forma, recomenda-se à Fiocruz buscar mecanismos que altere o modelo de gestão pelo qual está submetida a fim de viabilizar as duas formas de incorporação de mão-de-obra.
Books on the topic "Limit state flexibility"
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Alexander, Proelss, and Hofmann Tobias. Part IV Transnational Organised Crime as Matter of Certain Branches of International Law, 20 Law of the Sea and Transnational Organised Crime. Oxford University Press, 2016. http://dx.doi.org/10.1093/law/9780198733737.003.0020.
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A decade ago, the High Level Panel on Threats, Challenges, and Change identified transnational organised crime (TOC) as one of the six clusters of threats that the international community has to face in the twenty-first century, thus recognizing and highlighting how important the suppression of TOC is for a more secure world. This chapter outlines the pertinent legal framework provided by the international law of the sea, sets out the circumstances under which states are entitled to exercise jurisdiction over foreign ships, and addresses many of the highly sensitive issues surrounding shipping interdiction. It argues that the international law of the sea establishes a legal framework for cooperation that, on one hand, sets comparatively narrow limits for unilateral enforcement measures, but at the same time leaves sufficient room for flexibility in respect of bilateral and multilateral approaches addressing the interdiction of suspected vessels.
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United States. Congress. House. Committee on Ways and Means. Subcommittee on Human Resources. and United States. General Accounting Office., eds. Welfare reform: With TANF flexibility, states vary in how they implement work requirements and time limits : report to the chairman, Subcommittee on Human Resources, Committee on Ways and Means, House of Representatives. Washington, D.C: United States General Accounting Office, 2002.
Find full textBook chapters on the topic "Limit state flexibility"
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Whiteside, Noel. "Transforming the unemployed: trade union benefits and the advent of state policy." In Labour and Working-Class Lives. Manchester University Press, 2017. http://dx.doi.org/10.7228/manchester/9781784995270.003.0005.
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The introduction of state insurance for the unemployed, under the 1911 National Insurance Act, forced the trade unions to make adjustments to their visions of how they treated the unemployed. Before the 1911 Act there was immense diversity and variation in how the trade unions supported their members and controlled the labour market through providing benefits for the unemployed. However, the 1911 Act, imposed a rigidity on unemployment, defining it by imposing a limit of benefits for 15 weeks per year, with those falling out of benefit being unfortunate rather than long-term unemployed. Since many unions ran the new state scheme it was their previous flexibility in providing benefits to a more liberally defined unemployed, and allowing local branch variation, was replaced by the state’s insistence on uniformity and centralisation.
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Gilbert, Andrew C. "The Limits of Foreign Authority." In International Intervention and the Problem of Legitimacy, 33–63. Cornell University Press, 2020. http://dx.doi.org/10.7591/cornell/9781501750267.003.0003.
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This chapter shows how foreign officials, like the High Representative and a range of Bosnian political elites, used mass publicity to legitimize and authorize their state-building actions and delegitimize those of their opponents. It investigates how Wolfgang Petritsch used the media to engage domestic politicians in attempts to guide their behavior toward foreign state-building goals, even as they sought to shape his actions to serve their own goals. In doing so, the chapter identifies political innovations as well as important limits to internationally instigated political transformation. In discursively stabilizing the ambivalence of his position, Petritsch relied upon and reproduced an image of postwar Bosnia and Herzegovina as caught in a transitory temporality, a temporary state of exception to the normal nation-state order of things. Operating according to a logic of ambivalence afforded Petritsch a calculated flexibility to tack back and forth between various positions of legitimacy and authority.
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"Advancing an Ecosystem Approach in the Gulf of Maine." In Advancing an Ecosystem Approach in the Gulf of Maine, edited by Sally McGee. American Fisheries Society, 2012. http://dx.doi.org/10.47886/9781934874301.ch4.
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<i>Abstract</i>.—There is a strong desire to move toward ecosystem-based fisheries management (EBFM) in New England. However, there are many other problems in U.S. fisheries that have prevented timely adoption of EBFM. Changes in the Magnuson Stevens Fishery Conservation and Management Act, requiring catch limits for federally managed fisheries, may help speed the movement toward ecosystembased approaches to fishery management. In the meantime, the term “integrated fishery management” (IFM) is being used by the New England Fishery Management Council to mean incorporating flexibility between fishery management plans to allow, and account for, mixed catch. If IFM is going to provide a step toward EBFM, there are several actions that must be taken: (1) adequate monitoring across all fisheries must be provided, (2) flexibility across existing management plans must encourage reporting and landing rather than discarding, (3) interjurisdictional coordination within and among states and federal management bodies must improve, and (4) application of the U.S./Canada Resource Sharing Understanding must expand.
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Karapapa, Stavroula. "Introduction." In Defences to Copyright Infringement, 1–26. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198795636.003.0001.
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The fourth industrial revolution has emerged through the advancement of new technologies, innovative services, and modern business models, which often rely on the use and re-use of copyright-protected content. Although having the potential to enhance public welfare, these technologies and services challenge the limits of copyright law, especially in the European Union where the approach to defensive rules lacks flexibility. Under EU copyright law, exclusive rights are drafted in broad terms and with a high degree of generality, whereas the so-called exceptions and limitations to copyright are narrowly drafted and strictly interpreted, with the result that the breadth of permissible use is rather narrow. Because the fourth industrial revolution promises innovation and business growth—stated objectives of EU copyright—it invites an examination of defensive rules as a whole. The book adopts a holistic approach in its exploration of the limits of permissibility under EU copyright, including legislatively mentioned exceptions and limitations, doctrinal principles, and rules external to copyright, with a view to unveiling possible gaps and overlaps, offering a novel classification of defensive rules, and evaluating the adaptability of the law towards technological change. In this light, the work attempts to offer a measure of conceptual organization for defences to copyright infringement that may foster the development of a fresh understanding on how defensive rules against copyright infringement operate as a system; how they unveil their normative force; where instances of gaps or overlaps exist between defences; and how defences should be developed in light of future law reform or possible interpretative expansion.
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Bronowski, Ada. "Lekta and the Foundations of a Theory of Language." In The Stoics on Lekta, 341–82. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198842880.003.0008.
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This chapter focuses on the katēgorēma. It examines its relational nature as that which is always attributed to something else, showing that the katēgorēma is at the heart of a nuclear relation cementing the unity of every state-of-affairs in reality. Everything in reality is part of at least one relation of attribution, and therefore holds true of it, and of many which are false. The further claim is put forward that all katēgorēmata are already embedded within an axiōma in such a way that there are no incomplete lekta in reality. Incompleteness is put down to a question of language and different degrees of success in expressing what there is in reality to say. The infinitival and conjugated forms of the verbs are thus expressive only insofar as a complete lekton in reality is thereby, however partially, picked out. This introduces the question of the limits of a given language and whether translation is possible because the flexibility of one language is not paralleled in another. Three things are ‘yoked together’: the expression, the lekton, and the tunchanon, the last being an odd term for an even odder item: half and half between the case-ptōsis and the external object. This hybrid status, it is argued, results from the overlap between the ontological status of a lekton as subsisting or obtaining, and its subsequently being true or false.
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Nancarrow, Susan, and Alan Borthwick. "The established allied health professions." In The Allied Health Professions, 83–106. Policy Press, 2021. http://dx.doi.org/10.1332/policypress/9781447345367.003.0004.
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This chapter explores in detail using the examples of optometry and radiography the early development of the well-established and more mature allied health professions who have had to negotiate their professional boundaries with the state and the medical profession. In many ways, it is these early disputes and negotiations that are responsible for shaping the modern health workforce and the allied health division of labour. Optometry and radiology constitute two clear examples of professions that may be regarded as established within contemporary mainstream healthcare. One has a long pre-modern history, with a degree of autonomy built on its claim to a unique knowledge base that is independent of medicine and a track record of retail business success; the other emerged firmly rooted in hospital practice comprising technicians competing with medicine within a medical sphere of practice. Optometry, historically male-dominated, was established prior to the advent of full medical hegemony and power; radiography, mainly female, arose within it. Yet, both continue to operate within limits to a scope of practice defined by the presence of two major medical specialities with which they closely interface: ophthalmology and radiology. Both groups have a clearly limited and subordinate role in the provision of healthcare within their own spheres, and both had to concede the right to make diagnoses within their fields of expertise. It is the latter that has so clearly influenced the limitations set on the prescribing of medicines for both groups, even in the current policy climate of workforce redesign and role flexibility.
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C. Morris, Stephen. "Resilient Health System and Hospital Disaster Planning." In Contemporary Developments and Perspectives in International Health Security - Volume 2 [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.95025.
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Disaster planning is integral component of hospital operations and management, and hospital resiliency is critical to society and health systems following a disaster. Additionally, hospitals, like all public institutions have significant risk of security incidents including terrorism, isolated and mass violence, social unrest, theft and vandalism, natural and human made disasters. Security and disaster planning are cumbersome, expensive and easy to deprioritize. When a hospital disaster is defined as anything that exceeds the limits of the facility to function at baseline, disasters and security incidents are intertwined: disasters create security problems and vice-versa. Hospital resiliency to disasters and security incidents stems from a systems-based approach, departmental and administrative participation, financial investment and flexibility. Significant best practices and lessons learned exist regarding disaster and security planning and ignorance or lack of adoption is tantamount to dereliction of duty on the part of responsible entities. This chapter consists of a review of the concepts of hospital disaster and security planning, response and recovery, as well as hospital specific disaster and security threats (risk) and their associated mitigations strategies. Risks will be presented follow a hazard vulnerability analysis (HVA), a common framework in emergency management, disaster planning and disaster medicine. As such, each element of risk is defined in terms of likelihood and impact of an event. Concepts of disaster medicine that are also addressed, as are administrative concerns, these elements are designed to be applicable to non-experts with an emphasis on cross disciplinary understanding. Additionally, elements are presented using incident and hospital incident command terminology and those not familiar should learn these concepts though free online training on the incident command system provided by several sources including The United States Federal Emergency Management Agency (FEMA), prior to reading.
Conference papers on the topic "Limit state flexibility"
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Carlucci, Alberto, Mariona Pahisa, and Kelvin Moneypenny. "An innovative methodology to determine the partial load factor for prestressing in cable supported bridges." In IABSE Congress, Stockholm 2016: Challenges in Design and Construction of an Innovative and Sustainable Built Environment. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2016. http://dx.doi.org/10.2749/stockholm.2016.0032.
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<p>The design of cable supported bridges of short to medium spans requires the resolution of how to separate the load and effect of the major components of permanent loading: Gravity and Prestressing. <p>The Eurocode allows to use the same Ultimate Limit State factor for the Gravity “G” and the Prestressing “P” for flexible bridges and prescribes to use different factors for stiff bridges. <p>However, there is no clear definition in the Eurocode of when a bridge can be considered flexible. The paper introduces the concept of the Stay Force Response Index (SFRI) to define the degree of flexibility of the bridge and describes a method for the definition of the prestressing partial factor derived through a parametric analysis of concrete cable supported bridge. <p>This method, which is generally applicable beyond the Eurocode, would allow the designer to have the confidence in undertaking optimized hence, more economic and more sustainable designs.
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Wilcox, Bryan, Harry Dankowicz, and Walter Lacarbonara. "Response of Electrostatically Actuated Flexible MEMS Structures to the Onset of Low-Velocity Contact." In ASME 2009 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/detc2009-87011.
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Near-grazing, low-velocity contact in vibro-impacting systems has been shown to result in dramatic changes in steady-state system response following rapid transient growth of deviations away from the pre-grazing steady-state response. In low-dimensional example systems such transitions are often associated with large jumps in response amplitude. Coupled with the rapidity of the transient dynamics, this phenomenology supports the design of limit-switch sensors that trigger at the onset of grazing contact. A particularly exciting area of application of such sensors, and one in which their implementation might offer particular advantages, is in the context of microelectromechanical structures. Here, desirable scaling effects, such as increased system frequencies, low damping, batch fabrication, and decreased packaging size, can be leveraged. Fabricating simple beam structures at the microscale is relatively easier than fabricating proof-mass-based lumped-parameter systems with elaborate suspension structures. Consequently, it often becomes necessary to account for the flexibility of participating mechanical members, for example doubly-clamped, silicon-based beam elements. Physical contact further poses modeling challenges, as the flexibility of the beam elements and that of the contact region necessitate a compliant, but very stiff model description. The present work investigates a sequence of reduced-order models for such a doubly-clamped beam, subject to capacitive electrostatic actuation and a low-compliance physical constraint localized at a point along the span of the beam. The objective is to determine whether grazing-induced transitions, characteristic of lumped-mass models, are retained in the flexible structure. Specifically, numerical simulations are employed to quantify the variations in the response amplitude following the onset of contact and to contrast these to a spreading of system energy across mechanical modes.
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Zelenka, Jan, Claudio Hoff, Andreas Wimmer, Claudio Christen, Robert Böwing, and Josef Thalhauser. "Optimum Operating Strategies for Gas Engines Using Variable Intake Valve Train." In ASME 2018 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icef2018-9523.
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The present publication describes investigations on a lean burn gas engine equipped with a variable intake valve train and demonstrates how steady state engine performance can be improved in comparison to a conventional state-of-the-art application with constant Miller timing. As the knock border represents a significant limitation of the operating range of gas engines, the engine specific knock limit was derived from measurements on a single cylinder research engine and transferred to a 1D simulation model of the corresponding multicylinder engine; a large bore, two stage turbocharged gas engine in the 5 MW power range with a variable intake valve train. Special attention was given to the setup of the simulation model to improve prediction quality and reduce simulation effort. An optimal strategy using the flexibility of a variable intake valve train for engine operation is presented that is capable of accommodating fluctuating gas qualities, which are described by the methane number. The operating strategy was derived from the 1D simulation model. The better performance than with a state-of-the-art strategy will be quantified in terms of engine efficiency while knocking combustion caused by low methane numbers is prevented. Since ambient temperatures in certain regions where the engine is operated do not remain stable throughout the year and ambient pressure varies depending on sea level, these issues must also be addressed. The temperature and density of the intake air have a large influence on the performance of the turbocharging unit and thus overall engine efficiency. The simulation results show the engine’s behavior under varying ambient conditions and outline potential strategies for improvement made possible by using variable valve timing on the intake side.
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Cerkovnik, Mark, S. Chang, and Cary Griffin. "Fatigue Analysis of Tether Chain in Hybrid Risers." In ASME 2012 31st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/omae2012-83954.
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Hybrid risers represent an excellent way to isolate the riser from most of the host vessel motions and thereby limit riser fatigue. A common arrangement features the riser supported by a buoyancy can via a tether chain. The tether chain is a cheap simple way to make the connection while providing flexibility for installation. However, in service the tether is under very high tension, and the chain is not really flexible in the face of small amplitude fatigue loads. The friction effectively “welds” the chain together. Moment and torque input to the system by first order vessel motions and vortex induced vibrations are carried through the chain and induce fatigue loading in the links. Analysis of the chain can be problematic because the determination of the detailed stress in the chain requires a refined FEA model with contact element between the links. From the global sense the analysis may require running hundreds of sea-state realizations in the time domain and the vortex induced vibration (VIV) assessment of thousands of current profiles. In this paper an efficient numerical method is described to rigorously determine fatigue damage at locations throughout the chain.
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Sadoughi, Mohammad Kazem, Meng Li, Chao Hu, and Cameron A. Mackenzie. "High-Dimensional Reliability Analysis of Engineered Systems Involving Computationally Expensive Black-Box Simulations." In ASME 2017 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/detc2017-68273.
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Reliability analysis involving high-dimensional, computationally expensive, highly nonlinear performance functions is a notoriously challenging problem. In this paper, we tackle this problem by proposing a new method, high-dimensional reliability analysis (HDRA), in which a surrogate model is built to approximate a performance function that is high dimensional, computationally expensive, implicit and unknown to the user. HDRA first employs the adaptive univariate dimension reduction (AUDR) method to build a global surrogate model by adaptively tracking the important dimensions or regions. Then, the sequential exploration-exploitation with dynamic trade-off (SEEDT) method is utilized to locally refine the surrogate model by identifying additional sample points that are close to the critical region (i.e., the limit-state function) with high prediction uncertainty. The HDRA method has three advantages: (i) alleviating the curse of dimensionality and adaptively detecting important dimensions; (ii) capturing the interactive effects among variables on the performance function; and (iii) flexibility in choosing the locations of sample points. The performance of the proposed method is tested through two mathematical examples, the results of which suggest that the method can achieve accurate and computationally efficient estimation of reliability even when the performance function exhibits high dimensionality, high nonlinearity, and strong interactions among variables.
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Haque, Mohammad Shafinul, and Calvin M. Stewart. "Modeling the Creep Deformation, Damage, and Rupture of Hastelloy X Using MPC Omega, Theta, and Sin-Hyperbolic Models." In ASME 2016 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/pvp2016-63029.
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Combined cycle power plants components such as steam pipe work, pressure vessels, boilers, heat exchangers, and gas turbine disks, etc. are exposed to elevated temperature and pressure operation conditions for longer durations. Components may fail within the elastic limit due to a time dependent deformation and damage mechanism called creep. Creep prediction models are used to determine the state of these components and to schedule optimum inspection, maintenance, and replacement intervals. In this study, the deformation, damage, and life of Hastelloy X is characterized using three recently developed models; the Omega, Theta projection, and Sin-hyperbolic models. An analysis is performed to compare the models in terms of accuracy, assumptions, constant identification techniques, flexibility in use, and limitations. The influence that final creep strain has on Theta and Omega model is discussed. Sixteen tests were performed at four different configurations of stress (2.1–36.5 ksi) and temperature (1200–1800°F). In the experimental data, Hastelloy X does not exhibit the primary stage. In this study, the secondary and tertiary creep stages are modeled. Creep deformation and rupture life data is used to optimize the constants for the three models. Predictions using these models are compared with experimental data. It is found that the novel Sin-hyperbolic model better fits the experimental data, and is easier to apply. The Omega model predicts longer life than the Sinh and the Theta Projection model. The rupture life prediction of the Theta projection model is the worst due to dependence on the critical creep strain rate. It is observed that the Hastelloy X final creep strain depends on stress and temperature; this leads to a less accurate critical creep strain rate prediction resulting in inaccurate rupture life predictions for the Theta projection model. The analytical damage of the Omega model exhibits a linear evolution with time while the Sinh model show a more realistic elliptical creep damage evolution with time. A process to determine the constants of all the models is clearly described. The dependence of the trajectory of the creep curves with respect to the constants is discussed in detail. An analytical derivation of each model is provided. Predictions of these three models show that the Sinh model produces a better creep deformation curve by normalizing the experimental creep strain rate data. It is found that overall the Sinh model offers more flexibility, prediction accuracy, and is easier to apply.
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Nessim, Maher. "Limit States Design and Assessment of Onshore Pipelines." In 2012 9th International Pipeline Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/ipc2012-90449.
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In 2005, guidelines for the application of reliability-based design and assessment (RBDA) to natural gas pipelines were developed under PRCI sponsorship. The methodology underlying these guidelines has since been adopted as a non-mandatory Annex in the CSA Z662 standard (Annex O). The benefits of reliability-based methods include consistent safety levels, optimized solutions that make best use of available resources and flexibility in addressing non-standard problems. The key limitations of the methodology are that it requires specialized expertise, good data and a significant analysis effort. One approach that has been successfully used to simplify the application of reliability-based methods is to develop simple design and assessment rules that are designed to meet specified safety levels. In this approach, which is referred to here as limit states design and assessment, the checking rules incorporate safety factors that are “calibrated” to meet pre-selected reliability targets, within a specified tolerance, over a wide range of possible design and assessment cases. Probabilistic analyses are performed as part of the development stage, but the resulting checks are deterministic. The basic elements required to calibrate limit states design and assessment checks have been developed as part of the RBDA methodology, making the development of a limit states approach feasible. This paper provides an overview of an ongoing Joint Industry Project to develop a limit states design and assessment standard that addresses the key threats to the safety of onshore pipelines. The benefits and limitations of this approach are discussed in comparison to the full RBDA approach, and the expected outcomes of the project are described.
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Cheng, Dah Yu. "The Distinction Between the Cheng and STIG Cycles." In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-90382.
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This paper identifies distinct features of the Cheng Cycle as compared to the steam injected gas turbine, STIG. Development started on the Cheng Cycle in 1974. After eight years of research and testing, the Cheng Cycle was commercialized in 1982. The commercial opportunity came by winning one of the State of California’s Energy Commission sponsored bids at the San Jose State University campus. The first Cheng Cycle power plant was built around the Allison 501KB gas turbine. The project was won on the merit of excellent thermal efficiency with maximum flexibility. It is also the most economical system because it can follow fluctuating electrical and steam loads independently. Financing, licensing and all appropriate permits were completed within one year. It took less than a year to construct and was on line by the end of 1984. Immediately, several distinct features were noticed: (1) the Cheng Cycle boosts power by 70% and efficiency by 40% over the simple cycle, (2) it can follow the electric and steam loads independently, (3) it demonstrated low emission and established 25 ppm NOx as BACT for the San Francisco Bay Area Air Quality District. In 1987, GE introduced their Steam Injected Gas Turbine, STIG, using the LM 2500 and LM 5000, and in the 1990’s GE also introduced the LM1600 version of STIG. The high pressure ratio of those engines resulted in low exhaust temperature. That is not efficient enough to power a steam cycle. Unfortunately, STIG confused some users into thinking that every steam injected gas turbine was a Cheng Cycle. STIG uses the traditional constant pressure waste heat boiler technology. Operation is limited to near full load because low exhaust temperature at partial load would cause dysfunctional heat imbalance in the heat recovery steam generator (HRSG). The Cheng Cycle, in comparison, adopted a variable pressure HRSG so its operating range extends from idle to full load. This variable pressure HRSG allows full heat recovery, whereas STIG has to limit its operating range to maintain heat transfer balance. This unique HRSG design means that the Cheng Cycle is a thermal feedback cycle. As in any feedback system it could oscillate, in this case the oscillations are between fuel-flow and steam-flow. The Cheng Cycle utilizes digital control technology to the system. The integrated system provides the user with smooth operation and rapid start-up and load change capability.
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Koduru, Smitha D., and Maher A. Nessim. "Development of Strain Demand and Capacity Distributions to Use in Limit States Design for Geotechnical Loads." In 2018 12th International Pipeline Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/ipc2018-78784.
Full textAbstract:
A limit states design approach for onshore pipelines has been developed as part of a multi-year joint industry project (JIP). As part of this project, reliability-based design rules were developed for geotechnical loads, including landslides, slope creep, seismic loads, frost heave and thaw settlement. In consideration of the modelling complexity of the soil movement mechanisms and pipe-soil interaction, and to allow for flexibility to incorporate future model developments, the design rule formulation is directly based on the distribution parameters of the strain demand and capacity of the pipeline. This paper describes the approach used to develop the strain demand and capacity distributions that are required to apply the design rules, as well as the applicable range of distribution parameters. Slope creep was selected as a basis for demonstrating the proposed process, as this loading mechanism occurs more frequently and the data to characterize the necessary uncertainties is available. General guidance related to the development of the strain demand distribution parameters for other geotechnical loads is also provided.
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Singla, G., B. Delatti, A. Scarpato, J. Barracas, W. Wang, and N. Demougeot. "Advanced Automated GT26 Combustion Tuning for Increased Operational Flexibility and Performance." In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-16086.
Full textAbstract:
Abstract Today’s advanced Gas Turbine (GT) combustion systems are designed to achieve low emission limits over a wide operational range. Regular combustion tuning is usually required to ensure that emissions are kept well within the plant compliance limits and that combustion dynamics levels are low enough to meet the mechanical integrity targets of all hot gas parts. These targets must be met during the full lifetime of the power plant, regardless of ambient conditions, fuel composition or engine degradation. Considering also the recent increase of combustor inspection intervals and the change in the GT loading profile due to the intermittent nature of renewable energies, it became advantageous to develop an automated GT26 combustion tuning control. Ansaldo Energia self-learning AutoTune system, based on the well proven product developed by Power Systems Manufacturing (PSM), tunes engine operating parameters to maintain emission and combustion dynamics within specified limits under varying ambient conditions, load ranges, gas compositions and increasing engine degradation. It increases the robustness of the operation concept by introducing dynamic set points instead of fixed settings. This results in tuning flexibility, continuous engine optimization and it helps to potentially eliminate manual engine adjustments during a major inspection cycle. After a general introduction on the operating concept of the GT26, the interaction between AutoTune and the GT controller is described together with the set-up and tuning principles. The universal AutoTune algorithm was adapted to the unique GT26 reheat architecture and flexibility, allowing for: (i) GT26 EV and SEV tuning for emissions and pulsations during stable conditions, (ii) tuning to minimize the minimum environmental load (MEL) with changing fuel gas properties or ambient temperature with the Low Part Load (LPL) concept, (iii) handling of very reactive fuels with high C2+ concentrations, (iv) tuning during transient conditions accounting for the variation of the GT thermal state. Based on robust experience after five successful GT26 installations, tuning attempts and successful tunings are statistically analyzed on a commercial plant over a period of several weeks to demonstrate the enlarged operational flexibility and performance of the GT26 equipped with AutoTune. The data analysis focuses on the Low Part Load operation, where Autotune achieved a robust decrease of MEL of 20MW, corresponding to a reduction of 4% in terms of combined cycle relative load.