Zeitschriftenartikel: „System collapse“

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Mehrabi, Zia. „Food system collapse“. Nature Climate Change 10, Nr. 1 (09.12.2019): 16–17. http://dx.doi.org/10.1038/s41558-019-0643-1.

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Zhang, Zhuo Qun, You Xin Lin und Hong Nan Li. „Wind-Induced Progressive Collapsed Performance of Cup-Type Transmission Tower-Line System“. Applied Mechanics and Materials 353-356 (August 2013): 2392–96. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.2392.

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The Cup-type transmission tower-line system was a classic representative of high voltage electric power carrier, which was an important lifeline project. However, it frequently collapsed under different environmental loadings, especially strong wind. In this work, four tower five line finite element models simulated wind-induced progressive collapse process by birth-to-death element technique in ABAQUS/Explicit. The numerical simulation results demonstrated that this application could describe the structural collapse performance clearly and effectively and transmission tower-line system collapse path depended on the number, position and last deformation of damage elements.

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Hasegawa, Kazuhiro, Ko Kitahara, Toshiaki Hara, Ko Takano, Haruka Shimoda und Takao Homma. „Evaluation of lumbar segmental instability in degenerative diseases by using a new intraoperative measurement system“. Journal of Neurosurgery: Spine 8, Nr. 3 (März 2008): 255–62. http://dx.doi.org/10.3171/spi/2008/8/3/255.

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Object In vivo quantitative measurement of lumbar segmental stability has not been established. The authors developed a new measurement system to determine intraoperative lumbar stability. The objective of this study was to clarify the biomechanical properties of degenerative lumbar segments by using the new method. Methods Twenty-two patients with a degenerative symptomatic segment were studied and their measurements compared with those obtained in normal or asymptomatic degenerative segments (Normal group). The measurement system produces cyclic flexion–extension through spinous process holders by using a computer-controlled motion generator with all ligamentous structures intact. The following biomechanical parameters were determined: stiffness, absorption energy (AE), and neutral zone (NZ). Discs with degeneration were divided into 2 groups based on magnetic resonance imaging grading: degeneration without collapse (Collapse[−]) and degeneration with collapse (Collapse[+]). Biomechanical parameters were compared among the groups. Relationships among the biomechanical parameters and age, diagnosis, or radiographic parameters were analyzed. Results The mean stiffness value in the Normal group was significantly greater than that in Collapse(−) or Collapse(+) group. There was no significant difference in the average AE value among the Normal, Collapse(−), and Collapse(+) groups. The NZ in the Collapse(−) was significantly higher than in the Normal or Collapse(+) groups. Stiffness was negatively and NZ was positively correlated with age. Stiffness demonstrated a significant negative and NZ a significant positive relationship with disc height, however. Conclusions There were no significant differences in stiffness between spines in the Collapse(−) and Collapse(+) groups. The values of a more sensitive parameter, NZ, were higher in Collapse(−) than in Collapse(+) groups, demonstrating that degenerative segments with preserved disc height have a latent instability compared to segments with collapsed discs.

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Tao, Zhigang, Tongxing Zhang, Daoyong Zhu, Weili Gong und Manchao He. „Physical Modeling Test on Deformation and Failure of Rock Slope with New Support System“. Advances in Civil Engineering 2020 (29.06.2020): 1–18. http://dx.doi.org/10.1155/2020/8825220.

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In order to explore the monitoring and control method of rock slope, indoor physical model testing of collapse control and monitoring were carried out with the example of a rock slope collapse area project in Jietai Temple in Beijing, China, as the prototype. Based on the similarity theory, in this study, a new structural support with Negative Poisson’s Ratio bolt and flexible anchored net was utilized to reinforce the rock slope. Following a graded loading sequence, the collapse failure characteristics and the overall control effect of energy absorption reinforcement measures were explored. The experimental results demonstrated that the entire process of slope collapse presented four distinct stages of failure: fracture generation, fracture propagation, partial collapse, and overall collapse. The full-field displacement nephogram and the displacement monitoring point of the collapse area indicated that the large deformation and failure of the collapsed surrounding rock were effectively controlled, while the Negative Poisson’s Ratio bolt and the flexible anchored net had good reinforcement effects. The experimental stress record presented that the change of pressure curve was an apparent regularity in the entire process of slope collapse, which reflects the change state of internal force of surrounding rock; it includes the function of monitoring of slope collapse. It was indicated that the Negative Poisson’s Ratio bolt along with the large-deformation flexible anchored net had good reinforcement monitoring effect on the rock slope collapse disaster.

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DAY, S. J., J. C. CARRACEDO und H. GUILLOU. „Age and geometry of an aborted rift flank collapse: the San Andres fault system, El Hierro, Canary Islands“. Geological Magazine 134, Nr. 4 (Juli 1997): 523–37. http://dx.doi.org/10.1017/s0016756897007243.

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The catastrophic slope failures and landslides that occur in the final stages of lateral collapses of volcanoes destroy much of the evidence for precursory deformation and the early stages of the collapses concerned. Aborted or incomplete collapse structures, although rare, are rich sources of information on these stages of development of catastrophic collapses. The San Andres fault system, on the volcanic island of El Hierro, is a relatively young (between about 545 and about 261–176 ka old) but inactive lateral collapse structure. It appears to represent an aborted giant landslide. It is developed along the flank of a steep-sided volcanic rift zone, and is bounded by a discrete strike-slip fault zone at the up-rift end, closest to the centre of the island. This geometry differs markedly from that of collapse structures on stratovolcanoes but bears some similarities to that of active fault systems on Hawaii. Although the fault system has undergone little erosion, cataclasites which formed close to the palaeosurface are well exposed. These cataclasites are amongst the first fault rocks to be described from volcano lateral collapse structures and include the only pseudotachylytes to have been identified in such structures to date. Their development at unusually shallow depths is attributed to large movements on the fault in a single event, the inferred aborted landslide, and a lack of pressurized pore water. The absence of pressurized fluids in the slumping block may have caused the San Andres fault system to cease moving, rather than develop into a giant volcanic landslide. The recognition that the San Andres fault system is inactive greatly reduces the estimated volcanic hazard associated with El Hierro. However, the lack of evidence for precursory deformation prior to the aborted landslide event is disturbing as it implies that giant lateral collapses can occur on steep-sided oceanic islands with little warning.

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Moede, John D. „Medical Aspects of Urban Heavy Rescue“. Prehospital and Disaster Medicine 6, Nr. 3 (September 1991): 341–48. http://dx.doi.org/10.1017/s1049023x00038784.

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The concept of Urban Heavy Rescue is gaining increasing recognition within the emergency response community. Urban Heavy Rescue has come to denote the unique demands for special equipment and personnel as the result of structural collapse. Recent earthquakes in California, the Philippines, and Soviet Armenia as well as the building collapses in Brownsville, Texas, and New York City provided excellent demonstrations of the concept of specialized structural collapse teams. These events even have prompted the Federal Emergency Management Agency (FEMA) to establish a National Urban Search and Rescue System of special task forces trained in victim location and extrication from collapsed structures. This system will comprise an immediate federal response mechanism for assisting first responders in such activities. The National Search and Rescue System was based on post-event evaluations that pointed out a need not only for more applicable equipment and trained personnel, but also for the timely placement of the these resources.

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Luo, Jing, Weilin Xu, Jun Deng, Yanwei Zhai und Qi Zhang. „Experimental Study on the Impact Characteristics of Cavitation Bubble Collapse on a Wall“. Water 10, Nr. 9 (15.09.2018): 1262. http://dx.doi.org/10.3390/w10091262.

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As a hydrodynamic phenomenon, cavitation is a main concern in many industries such as water conservancy, the chemical industry and medical care. There are many studies on the generation, development and collapse of cavitation bubbles, but there are few studies on the variation of the cyclic impact strength on walls from the collapse of cavitation bubbles. In this paper, a high-speed dynamic acquisition and analysis system and a pressure measuring system are combined to study the impact of a cavitation bubble generated near a wall for various distances between the cavitation bubble and the wall. The results show that (1) with the discriminating criteria of the impact pressure borne by the wall, the critical conditions for the generation of a micro-jet in the collapse process of the cavitation bubbles are obtained, and therefore collapses of cavitation bubbles near the wall are mainly divided into primary impact area collapses, secondary impact area collapses and slow release area collapses; (2) it can be seen from the impact strength of the cavitation bubble collapse on the wall surface that the impact of cavitation bubbles on the wall surface during the first collapse decreases as γ (the dimensionless distance between the cavitation bubble and the wall) increases, but the impact of the second collapse on the wall surface increases first and then decreases sharply. When γ is less than 1.33, the impact on the wall surface is mainly from the first collapse. When γ is between 1.33 and 2.37, the impact on the wall surface is mainly from the second collapse. These conclusions have potential theoretical value for the utilization or prevention and control technologies for cavitation erosion.

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Houston, Sandra L., Hisham H. H. Mahmoud und William N. Houston. „Down-Hole Collapse Test System“. Journal of Geotechnical Engineering 121, Nr. 4 (April 1995): 341–49. http://dx.doi.org/10.1061/(asce)0733-9410(1995)121:4(341).

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Tian, Li, Xin Zhang und Xing Fu. „Fragility analysis of a long-span transmission tower–line system under wind loads“. Advances in Structural Engineering 23, Nr. 10 (27.02.2020): 2110–20. http://dx.doi.org/10.1177/1369433220903983.

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Numerous transmission towers have collapsed due to experiencing strong winds; therefore, the purpose of this article is to investigate the collapse mechanism and the anti-collapse performance of a long-span transmission tower–line system. The detailed finite element model of a typical tower–line system is established in ABAQUS. A global damage index is proposed to quantitatively estimate the overall damage of the structure and define the collapse criteria. An incremental dynamic analysis is performed to obtain the collapse mechanism and the ultimate capacity of the structure. Subsequently, a fragility analysis for evaluating the anti-collapse performance is conducted due to the uncertainty of wind loads. Eventually, the influence of the wind attack angle and the length of the side spans on the fragility is discussed. The results demonstrate that the proposed global damage index is capable of quantitatively reflecting the overall damage and assessing the ultimate capacity of the structure. In addition, the uncertainty of the wind load has a significant influence on the ultimate capacity and the failure position. Furthermore, the results reveal that the wind attack angle and the length of the side spans have an apparent effect on the fragility of the structure.

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M. Becerra, Laura, Carlo Bianco, Chris Fryer, Jorge Rueda und Remo Ruffini. „On the Induced Gravitational Collapse“. EPJ Web of Conferences 168 (2018): 02005. http://dx.doi.org/10.1051/epjconf/201816802005.

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The induced gravitational collapse (IGC) paradigm has been applied to explain the long gamma ray burst (GRB) associated with type Ic supernova, and recently the Xray flashes (XRFs). The progenitor is a binary systems of a carbon-oxygen core (CO) and a neutron star (NS). The CO core collapses and undergoes a supernova explosion which triggers the hypercritical accretion onto the NS companion (up to 10-2 M⊙s-1). For the binary driven hypernova (BdHNe), the binary system is enough bound, the NS reach its critical mass, and collapse to a black hole (BH) with a GRB emission characterized by an isotropic energy Eiso > 1052 erg. Otherwise, for binary systems with larger binary separations, the hypercritical accretion onto the NS is not sufficient to induced its gravitational collapse, a X-ray flash is produced with Eiso < 1052 erg. We’re going to focus in identify the binary parameters that limits the BdHNe systems with the XRFs systems.

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Zhang, Wei. „Research Status on the Collapse Mechanism and Prevention Measures of Mega Composite Structural Systems“. MATEC Web of Conferences 175 (2018): 04008. http://dx.doi.org/10.1051/matecconf/201817504008.

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Mega composite structural system presents wide application prospects in high-rise and super high-rise buildings. However, research concerning the important issues of the seismic behavior, collapse mechanism, and prevention from progressive collapse for such new structural systems under severe earthquakes is quite limited. This paper will summarize the current research status, followed by the discussions on the collapse and prevention mechanisms of high-rise and super high-rise mega composite structural systems under severe earthquakes, the theoretical basis on progressive collapse mechanisms, numerical simulation techniques, and test methods. The failure modes of high-rise mega composite structures were studied firstly, followed by the collapse mechanisms and the associated criteria and indices. In addition, a new numerical technique for simulating the non-linear structural collapses considering large deformations will be presented, along with the relevant test results. This study shows that analysis method, damage accumulation model, failure criteria, appropriate preventive measures, and improved collapse experimental verification methods are all important seismic design considerations for high-rise and super high-rise mega composite structures. Based on the study results, recommendations for collapse and prevention mechanisms of high-rise buildings are proposed.

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Wang, Duo Zhi, Jun Wu Dai und Chen Xiao Zhang. „Seismic Damage Analysis for Multi-Story Masonry Building with R. C. Frames on Ground Floor“. Applied Mechanics and Materials 204-208 (Oktober 2012): 2555–58. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.2555.

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Multi-story Masonry Building with R. C. Frames on Ground Floor (Framed-Ground Floor Structure for short) which has serious seismic damage and high collapsed rate, is the unreasonable structure system. However, the structure system not be abolished for economic reason. Collapse types of that are divided into collapse of ground floor, collapse of transition layer, global collapse. And seismic damage is also serious for frame column and shear wall. Experiences are obtained from above seismic damage, and the following aspects should be taken into account in the future. 1. The shear wall can be increased to improve stiffness of weak layer. And designer should try to arrange the walls equably. 2. In order to avoid stiffness mutation, stiffness ratio between ground frame and transition layer can be adjusted. 3. Collapse resistant design of Framed-Ground Floor Structures should be emphasized.

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Galvis, Francisco A., Eduardo Miranda, Pablo Heresi, Héctor Dávalos und Jorge Ruiz-García. „Overview of collapsed buildings in Mexico City after the 19 September 2017 (Mw7.1) earthquake“. Earthquake Spectra 36, Nr. 2_suppl (30.07.2020): 83–109. http://dx.doi.org/10.1177/8755293020936694.

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An intraslab normal-faulting earthquake struck the central region of Mexico on 19 September 2017, leading to the collapse of 44 buildings in Mexico City. After the earthquake, the authors collected information in situ and through social media about the collapsed buildings, which was statistically processed to identify the causes of their collapse. This article presents the main collapse statistics, which revealed that 64% of the collapsed buildings had between 1 and 5 stories, 61% had a seismic-force-resisting system based on reinforced concrete columns with flat slabs, 57% experienced a soft-story mechanism, 91% were built before 1985, 43% were located at the corner blocks, and 10% exhibited pounding with neighboring buildings. The spatial distribution of the collapsed buildings and the recorded ground motion features suggest that short- and medium-period buildings having well-known vulnerabilities were particularly prone to collapse under amplified high-frequency seismic waves typical of intraslab normal-faulting earthquakes, such as the 2017 Puebla–Morelos earthquake.

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Tsai, Ming Kuan, und Nie Jia Yau. „Enhancing Collapse Detection and Alarms in Bridge Management“. Applied Mechanics and Materials 479-480 (Dezember 2013): 1180–84. http://dx.doi.org/10.4028/www.scientific.net/amm.479-480.1180.

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Taiwan has more than 28,000 bridges. In the past decades, because of scour problems, some bridges collapsed. Such accidents have caused severe economic losses and killed many people. Although Taiwanese government agencies have mitigated the relationship between natural hazards and bridge collapse, the lack of mechanisms for bridge collapse detection and on-site emergency alarms still exists at bridge sites. Therefore, this study proposes a bridge safety monitoring information system. With mixed collapse detectors, this information system could identify the status of various bridge elements in real time. After two-year tests at six bridge sites, this study confirmed that the performance of the bridge safety monitoring information system. Overall, this study helps for similar applications in bridge and disaster management.

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Dietz, Henry A., und David J. Myers. „From Thaw to Deluge: Party System Collapse in Venezuela and Peru“. Latin American Politics and Society 49, Nr. 2 (2007): 59–86. http://dx.doi.org/10.1111/j.1548-2456.2007.tb00407.x.

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AbstractWhat conditions facilitate party system collapse, the farthest-reaching variant of party system change? How does collapse occur? Numerous studies of lesser types of party system change exist, but studies of party system collapse are rare. This study draws on the existing literature and the cases of party system collapse in Venezuela (1988–2000) and Peru (1985–95) to advance some answers to the important questions about the phenomenon. The study posits three conditions that predispose political party systems to collapse: the presence of an acute or sustained crisis that questions the ability of system-sustaining political parties to govern; extremely low or extremely high levels of party system institutionalization; and the emergence of an anti-establishment figure with the desire and personal authority to generate a viable alternative to the established party system. The study also posits a three-election sequential process during which collapse takes place.

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Liu, Yan Ning, und Jun Fu Lu. „The Solution on Problem of Soft Soil Layer’s Collapse in Xin Kailing Tunnel and Evaluations on its Effect“. Applied Mechanics and Materials 90-93 (September 2011): 2401–7. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.2401.

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This paper presents the solution on the soft soil layer’s collapse of Xin Kailing Tunnel in China based on the analysis on its causes. The effect of the solution is evaluated by site survey and finite element analysis. The results show that the geological factor mainly leads to collapse; the crucial factor of preventing the collapse from happening is to give a better description of the tunnel face, to analyze and predict conditions of wall rocks which are in front of the tunnel face in time and to evaluate precisely whether the wall rocks and supporting system are strong enough or not; effective ways to solve the collapse problem is to strengthen supporting system of the being influenced parts in the tunnel, to seal wall rocks in collapsed possibly part as well as to add supporting system in time; the minimum safety factor of the solution in this project is about 3.1 which meets official standards of the tunnel construction; the solutions on the soft soil layer’s collapse of Xin Kailing Tunnel is effective, safe and reliable.

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Mercier, James, Eligio Alvarez, Juan Marfil, Mark Bloschock und Ronald Medlock. „Bridge Collapse Detection System in Texas“. Transportation Research Record: Journal of the Transportation Research Board 11s (Januar 2005): 403–8. http://dx.doi.org/10.3141/trr.11s.354m173605169462.

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Izbekov, Pavel, Evgenii Gordeev, John Eichelberger und Michael West. „Magma system response to edifice collapse“. Journal of Volcanology and Geothermal Research 263 (August 2013): 1–2. http://dx.doi.org/10.1016/j.jvolgeores.2013.09.001.

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Hetland, Gabriel. „From System Collapse to Chavista Hegemony“. Latin American Perspectives 44, Nr. 1 (22.09.2016): 17–36. http://dx.doi.org/10.1177/0094582x16666018.

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During the 14 years Hugo Chávez was in office, Venezuela’s party system experienced a 180-degree shift. When Chávez was elected in 1998, Venezuela’s party system had collapsed because of a two-decade-long economic-cum-political crisis. His initial appeal was built, in large part, on his antiparty message, a stance that continued through the first half of his time in office. A series of factors, principally the need for a more cohesive organization to combat an intransigent opposition, led to the creation of the Partido Socialista Unido de Venezuela (United Socialist Party of Venezuela—PSUV) in 2007. The PSUV quickly became Venezuela’s largest party and the linchpin of a new hegemonic system. The contradictions of that system are manifested in the split between the PSUV’s right and left wings, and the hegemony of Chavismo is now in doubt. Durante los 14 años de la presidencia de Hugo Chávez, el sistema de partidos de Venezuela sufrió un giro de 180°. Cuando Chávez fue elegido en 1998, el sistema ya había colapsado debido a la larga crisis económica y política que ya llevaba dos décadas. Su llamamiento inicial se fundamentó, en gran parte, en un mensaje antipartido, una postura que continuó durante la primera mitad de su mandato. Una serie de factores—principalmente, la necesidad de una organización más cohesiva para combatir a la oposición intransigente — llevó a la creación del Partido Socialista Unido de Venezuela (PSUV) en 2007. El PSUV rápidamente se convirtió en el partido más grande de Venezuela y en la pieza esencial de un nuevo sistema hegemónico. Las contradicciones del sistema se manifiestan en la brecha entre el ala izquierdista y el ala derechista del PSUV y la hegemonía del chavismo ahora está en entredicho.

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Day, Robert W. „Discussion: Down-Hole Collapse Test System“. Journal of Geotechnical Engineering 122, Nr. 10 (Oktober 1996): 869–72. http://dx.doi.org/10.1061/(asce)0733-9410(1996)122:10(869).

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Yongyan, YU, MA Dong und Fu Chongtao. „Study on early-warning System of Karst Tunnel Collapse“. E3S Web of Conferences 198 (2020): 02021. http://dx.doi.org/10.1051/e3sconf/202019802021.

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During the construction of karst Tunnel, tunnel collapse often occurs. The establishment of early-warning system of tunnel collapse can effectively ensure the construction safety, but the research is insufficient. Based on the combination of theoretical analysis and engineering practice, this paper puts forward to early-warning system for karst tunnel collapse. (1) The evaluation index system of karst tunnel collapse is composed of anchor axial force, displacement, anchor pull-out force and steel arch stress. (2) The relationship between evaluation index and warning level is determined, and the early-warning system of tunnel collapse is established. (3) The model applied to Chong’anjiang tunnel collapse warning, and achieved good results.

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Wang, Yi Xuan, und Lei Huang. „Research on Numerical Model for Earthquake Induced Progressive Collapse of High-Rise Buildings“. Applied Mechanics and Materials 716-717 (Dezember 2014): 223–26. http://dx.doi.org/10.4028/www.scientific.net/amm.716-717.223.

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Progressive collapse is defined as the collapse of the whole building due to local weak stories or weak zones. In this paper, collapse should theoretically be avoided for any building under any earthquake, it is necessary to study the collapse behavior of buildings to acquire a better understanding of the collapse mechanism and to find efficient methods to prevent it. The collapse process highly depends on the feature of the whole structural system, so numerical simulation becomes a major method to study it. Based on the finite element method, by selecting the appropriate cell death and cell contact algorithm criterion can better simulate the structure collapsed in an earthquake under the continuity of the whole process of destruction, to help understand the causes and mechanism of structural damage. The real buildings are analyzed to study the failure mechanism of the structure. The models proposed are reasonable to study the seismic collapse mechanism of high-rise buildings.

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Amirtharajah, Appiah. „Optimum Backwashing of Filters with Air Scour: A Review“. Water Science and Technology 27, Nr. 10 (01.05.1993): 195–211. http://dx.doi.org/10.2166/wst.1993.0232.

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The problems occurring in the filtration facilities of water treatment plants, such as mudballs and poor initial filtrate quality are associated with the effectiveness of backwashing. Backwashing with water alone to fluidize the media is an inherently weak cleaning process. The effectiveness of backwashing is significantly improved by the use of air scour simultaneously with subfluidization water wash. When air and subfluidization water flowed concurrently through porous media, a condition termed “collapse- pulsing” occurred in which air pockets formed and collapsed within the bed. A theory has been developed that predicted the combinations of air and water flows that caused collapse-pulsing to occur. Model filter systems have shown that the fluid mechanical condition termed “collapse-pulsing” is also the condition of optimum removal of particles from the media grains during backwashing. The theoretical aspects of collapse-pulsing have been confirmed with an experimental filter system having an endoscope, high speed video system with freeze frame capability for visual observations and an XY Coordinator with computer hardware and software which enabled the determination of velocities of filter grains during air scour. Additional studies on optimum removal of particles from media during air scour have also demonstrated that the results may be extended to dual media filters and are valid at the plant scale too.

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Mainwaring, Scott. „Party System Institutionalization, Party Collapse and Party Building“. Government and Opposition 51, Nr. 4 (01.08.2016): 691–716. http://dx.doi.org/10.1017/gov.2016.21.

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This essay reviews five important recent books on party system institutionalization, party collapse and party building. The first section analyses broader lessons about party system institutionalization derived from these books. What have we learned about how party system institutionalization varies over time and space and about its causes? All five volumes underscore the difficulty of institutionalizing democratic party systems in contemporary Asia, Africa and Latin America. At the same time, they demonstrate that there have been some successful cases of party building and party system institutionalization. In all three regions, variance across countries is great. The three books on Latin America show that sharp conflict and programmatic differences are good for institutionalization, partially countering earlier arguments about the perils of polarization. Across regions, erstwhile authoritarian ruling parties have sometimes helped to forge institutionalized party systems under competitive regimes. The rest of the essay analyses the three single-authored books in some detail and provides brief overviews of the two edited volumes.

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Sharif, M., und Rubab Manzoor. „Dark energy and collapsing axial system“. International Journal of Modern Physics D 26, Nr. 06 (Dezember 2016): 1750057. http://dx.doi.org/10.1142/s0218271817500572.

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This paper investigates the effects of dark source term on the dissipative axially symmetric collapse by taking self-interacting Brans–Dicke (SBD) gravity as a dark energy (DE) candidate. We discuss physically feasible energy source of the model and formulate all the dynamical variables as well as structure scalars. It is found that the dark source term is one of the source of anisotropy and dissipation in the system. Further, we obtain structure scalars in this background. In order to discuss factors describing dissipative collapse, we develop equations related to the evolution of dynamical variables, heat transport equation as well as super-Poynting vector. We conclude that the thermodynamics of the collapse, evolution of kinematical terms (like expansion scalar, shear and vorticity) and inhomogeneity are affected by dark source term. Finally, we study the existence of radiation having repulsive gravitational nature in this collapse scenario.

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Watts, Jonathan. „tokyo Japan's health system “close to collapse”“. Lancet 356, Nr. 9237 (Oktober 2000): 1251. http://dx.doi.org/10.1016/s0140-6736(05)73858-7.

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Sputo, Thomas, und Duane S. Ellifritt. „Collapse of Metal Building System during Erection“. Journal of Performance of Constructed Facilities 5, Nr. 4 (November 1991): 251–57. http://dx.doi.org/10.1061/(asce)0887-3828(1991)5:4(251).

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Gautreau, Ronald, und Jeffrey M. Cohen. „Gravitational collapse in a single coordinate system“. American Journal of Physics 63, Nr. 11 (November 1995): 991–99. http://dx.doi.org/10.1119/1.18002.

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Ingram, M. „Russia warned of collapse of health system“. BMJ 311, Nr. 7010 (07.10.1995): 897. http://dx.doi.org/10.1136/bmj.311.7010.897.

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The Lancet. „The collapse of the Venezuelan health system“. Lancet 391, Nr. 10128 (April 2018): 1331. http://dx.doi.org/10.1016/s0140-6736(16)00277-4.

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Melatos, Andrew, und Peter Robinson. „Magnetised Wave Collapse in Solar System Plasmas“. Publications of the Astronomical Society of Australia 10, Nr. 4 (1993): 283–86. http://dx.doi.org/10.1017/s1323358000025881.

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AbstractClumpy, intense wave packets observed in situ in the Jovian and terrestrial electron foreshocks, and in the Earth’s auroral acceleration zone, point to the existence of non-linear plasma turbulence in these regions. In non-linear turbulence, wave packets collapse to short scales and high fields, stopping only when coherent wave-particle interactions efficiently dissipate the energy in the waves. The purpose of this paper is to examine the shortest scales and highest fields achieved during collapse in a strongly magnetised plasma, and identify parts of the solar system where the magnetised aspects of wave collapse are important.

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Ishida, Shuzo, und Kiyotaka Morisako. „Collapse of SDOF System to Harmonic Excitation“. Journal of Engineering Mechanics 111, Nr. 3 (März 1985): 431–48. http://dx.doi.org/10.1061/(asce)0733-9399(1985)111:3(431).

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Min, Kyoung W., und Chul S. Choi. „Cold collapse of a spherical stellar system“. Monthly Notices of the Royal Astronomical Society 238, Nr. 1 (Mai 1989): 253–59. http://dx.doi.org/10.1093/mnras/238.1.253.

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Garny, M., und T. Konstandin. „Gravitational collapse in the Schrödinger-Poisson system“. Journal of Cosmology and Astroparticle Physics 2018, Nr. 01 (09.01.2018): 009. http://dx.doi.org/10.1088/1475-7516/2018/01/009.

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Marti, Genoveva. „Do modal distinctions collapse in Carnap's system?“ Journal of Philosophical Logic 23, Nr. 6 (Dezember 1994): 575–93. http://dx.doi.org/10.1007/bf01052778.

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Rein, Gerhard, und Lukas Taegert. „Gravitational Collapse and the Vlasov–Poisson System“. Annales Henri Poincaré 17, Nr. 6 (19.07.2015): 1415–27. http://dx.doi.org/10.1007/s00023-015-0424-y.

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37

Yin, Zhaoqin, Zemin Huang, Chengxu Tu, Xiaoyan Gao und Fubing Bao. „Dynamic Characteristics of Bubble Collapse Near the Liquid-Liquid Interface“. Water 12, Nr. 10 (08.10.2020): 2794. http://dx.doi.org/10.3390/w12102794.

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Bubble collapse near the liquid-liquid interface was experimentally studied in this paper, and the dynamic evolution of a laser-induced bubble (generation, expansion, and collapse) and the liquid-liquid interface (dent and rebound) were captured by a high-speed shadowgraph system. The effect of the dimensionless distance between the bubble and the interface on the direction of the liquid jet, the direction of bubble migration, and the dynamics of bubble collapse were discussed. The results show that: (1) The jet generated during bubble collapse always directs toward the denser fluid; (2) bubble collapses penetrate the interface when the bubble is close to the interface; (3) three different shapes of the liquid-liquid interface—that is, a mushroom-shaped liquid column, a spike droplet, and a spherical liquid droplet—were observed.

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Zhang, Zhuoqun, Hongnan Li, Gang Li, Wenming Wang und Li Tian. „The Numerical Analysis of Transmission Tower-Line System Wind-Induced Collapsed Performance“. Mathematical Problems in Engineering 2013 (2013): 1–11. http://dx.doi.org/10.1155/2013/413275.

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The numerical simulation of transmission tower-line systems' progressive collapse performance is considered as a major research hotspot and significant project, due to the increasing number of wind-induced collapse accidents recently. In this study, the finite element models for single tower and transmission tower-line system were established to simulate wind-induced progressive collapse by birth-to-death element technique in ABAQUS/Explicit. The wind field, based on the Kaimal fluctuating wind power spectrum and harmonic superposition method, was constructed by MATLAB commercial software. The current research focuses on the dynamic behaviour and the mechanism of a typical transmission tower-line system progressive collapse under wind action with clear step-by-step description. The numerical simulation results demonstrated that transmission tower-line system collapse mechanism depended on the number, position and last deformation of damage elements. Since the gallop effect of conductor and ground lines were ignored in the single tower model, the transmission tower-line system model, which has higher computational precision than the single tower model, is relatively accurate and recommended strongly in the design.

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Ogloblina, Daria, Steffen J. Schmidt und Nikolaus A. Adams. „Simulation and analysis of collapsing vapor-bubble clusters with special emphasis on potentially erosive impact loads at walls“. EPJ Web of Conferences 180 (2018): 02079. http://dx.doi.org/10.1051/epjconf/201818002079.

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Cavitation is a process where a liquid evaporates due to a pressure drop and re-condenses violently. Noise, material erosion and altered system dynamics characterize for such a process for which shock waves, rarefaction waves and vapor generation are typical phenomena. The current paper presents novel results for collapsing vapour-bubble clusters in a liquid environment close to a wall obtained by computational fluid mechanics (CFD) simulations. The driving pressure initially is 10 MPa in the liquid. Computations are carried out by using a fully compressible single-fluid flow model in combination with a conservative finite volume method (FVM). The investigated bubble clusters (referred to as “clouds”) differ by their initial vapor volume fractions, initial stand-off distances to the wall and by initial bubble radii. The effects of collapse focusing due to bubble-bubble interaction are analysed by investigating the intensities and positions of individual bubble collapses, as well as by the resulting shock-induced pressure field at the wall. Stronger interaction of the bubbles leads to an intensification of the collapse strength for individual bubbles, collapse focusing towards the center of the cloud and enhanced re-evaporation. The obtained results reveal collapse features which are common for all cases, as well as case-specific differences during collapse-rebound cycles. Simultaneous measurements of maximum pressures at the wall and within the flow field and of the vapor volume evolution show that not only the primary collapse but also subsequent collapses are potentially relevant for erosion.

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Andreini, Marco, Anna de Falco, Linda Giresini und Mauro Sassu. „Collapse of the Historic City Walls of Pistoia (Italy): Causes and Possible Interventions“. Applied Mechanics and Materials 351-352 (August 2013): 1389–92. http://dx.doi.org/10.4028/www.scientific.net/amm.351-352.1389.

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In the paper are discussed the likely causes of the collapse and the temporary safety features adopted to secure a collapsed portion of the Historic Walls of the city of Pistoia (Italy). The walls of medieval origin, affected by various subsequent modifications and alterations, have been subjected to a sudden collapse, after a period of heavy rain, for a length of about 25 meters. Hereby are described the probable causes of the collapse, due to a poor quality of the walls (external façades with external layer made up of river pebbles and inner filling material in-coherent), height of building is not modest (approximately eleven meters), a significant differential in height between the two faces (about four meters) and a not unlikely rotation of the base. It is proposed a technique of temporary reinforcement with a system of steel tie-beams and braces with a view to the work of reconstruction of the partially collapsed and consolidation of the lateral parts of wall.

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Wei, Chih-Chiang. „COLLAPSE WARNING SYSTEM USING LSTM NEURAL NETWORKS FOR CONSTRUCTION DISASTER PREVENTION IN EXTREME WIND WEATHER“. JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 27, Nr. 4 (20.04.2021): 230–45. http://dx.doi.org/10.3846/jcem.2021.14649.

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Strong wind during extreme weather conditions (e.g., strong winds during typhoons) is one of the natural factors that cause the collapse of frame-type scaffolds used in façade work. This study developed an alert system for use in determining whether the scaffold structure could withstand the stress of the wind force. Conceptually, the scaffolds collapsed by the warning system developed in the study contains three modules. The first module involves the establishment of wind velocity prediction models. This study employed various deep learning and machine learning techniques, namely deep neural networks, long short-term memory neural networks, support vector regressions, random forest, and k-nearest neighbors. Then, the second module contains the analysis of wind force on the scaffolds. The third module involves the development of the scaffold collapse evaluation approach. The study area was Taichung City, Taiwan. This study collected meteorological data from the ground stations from 2012 to 2019. Results revealed that the system successfully predicted the possible collapse time for scaffolds within 1 to 6 h, and effectively issued a warning time. Overall, the warning system can provide practical warning information related to the destruction of scaffolds to construction teams in need of the information to reduce the damage risk.

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Chen, Juan Nong, und Zhi Xin Yue. „The System of Soil Management in the Coal Mining Collapse Area“. Applied Mechanics and Materials 361-363 (August 2013): 871–74. http://dx.doi.org/10.4028/www.scientific.net/amm.361-363.871.

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The environment restoring of the coal mining collapse area directly relates the region economy, the social stabilization, the ecological environment, also relates the sustainable development of mining area. And this is a serious problem for the mining area in China. In order to improve the environment of mining area, this paper analyzes the presence of collapse area in China. This paper analyzes the damages of coal mining collapse and the problems existing in the management and regulation of the collapse region. In addition to researching the way of soil management of coal mining subsidence area with Geographic Information System technology, he also exemplified the feasibility and necessity in soil management of the coal mining collapse area with Geographic Information System technology.

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Kim, Nari, Calvin C. H. Cheng und M. Cynthia Goh. „Universal aqueous synthesis of ultra-small polymer-templated nanoparticles: synthesis optimization methodology for counterion-collapsed poly(acrylic acid)“. Canadian Journal of Chemistry 96, Nr. 1 (Januar 2018): 44–50. http://dx.doi.org/10.1139/cjc-2017-0444.

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A long polyelectrolyte chain collapses into a nano-sized particle upon the addition of counterions under appropriate solution conditions. This phenomenon forms the basis for a simple universal method for aqueous synthesis of ultra-small (<10 nm) metal, metal oxide, and other types of nanoparticles in the following manner: the counterion-collapsed polyelectrolyte chains are made stable by crosslinking, effectively trapping the counterions, which are subsequently chemically modified, to form metal nanoparticles via reduction or metal oxides nanoparticles via oxidation, within the collapsed polymer nanoparticle. This highly versatile platform methodology can be applied to almost any polyelectrolyte–counterion pair, making possible the rapid development of syntheses of different nanoparticles within the same chemical environment. Using poly(acrylic acid) as a model system, a methodology for the optimization of conditions for the polyelectrolyte collapse by various mono- and multi-valent metal cations is developed. The optimal counterion concentration did not correlate with ionic strength and metal ion valency and was highly variable from system to system. By monitoring the polyelectrolyte conformation using viscosity and turbidity measurements, the appropriate metal ion concentration for each nanoparticle system was determined.

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Goddard, Joe, und Ken Kamrin. „Dissipation potentials from elastic collapse“. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 475, Nr. 2226 (Juni 2019): 20190144. http://dx.doi.org/10.1098/rspa.2019.0144.

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Generalizing Maxwell's (Maxwell 1867 IV. Phil. Trans. R. Soc. Lond. 157 , 49–88 ( doi:10.1098/rstl.1867.0004 )) classical formula, this paper shows how the dissipation potentials for a dissipative system can be derived from the elastic potential of an elastic system undergoing continual failure and recovery. Hence, stored elastic energy gives way to dissipated elastic energy. This continuum-level response is attributed broadly to dissipative microscopic transitions over a multi-well potential energy landscape of a type studied in several previous works, dating from Prandtl's (Prandtl 1928 Ein Gedankenmodell zur kinetischen Theorie der festen Körper. ZAMM 8 , 85–106) model of plasticity. Such transitions are assumed to take place on a characteristic time scale T , with a nonlinear viscous response that becomes a plastic response for T → 0 . We consider both discrete mechanical systems and their continuum mechanical analogues, showing how the Reiner–Rivlin fluid arises from nonlinear isotropic elasticity. A brief discussion is given in the conclusions of the possible extensions to other dissipative processes.

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Charleson, Andrew, und Marcial Blondet. „Seismic Reinforcement for Adobe Houses with Straps from Used Car Tires“. Earthquake Spectra 28, Nr. 2 (Mai 2012): 511–30. http://dx.doi.org/10.1193/1.4000014.

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After outlining introductory research on a proposed reinforcing system for adobe housing using straps cut from used car tires, the paper reports on full-scale tests. One dynamic and two static tests are described and results presented. The most significant outcome was that a single-room adobe house reinforced by tire straps successfully withstood the strong shaking that routinely collapses unreinforced adobe dwellings. The reinforced house strength, as measured during the shaking, exceeded the requirements of the Peruvian seismic code. This type of reinforced adobe can undergo large horizontal deformations without collapse. Design, construction, economic, and cultural issues are discussed prior to concluding that the proposed system can prevent collapse of adobe houses during damaging earthquakes.

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Su, Jian, Jieming Li, Lingsheng Tan und Xiaodan Huang. „Development of the IoT-based Monitoring System for Scaffold Shoring System of Concrete Formwork“. MATEC Web of Conferences 175 (2018): 03072. http://dx.doi.org/10.1051/matecconf/201817503072.

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Construction safety monitoring is an important approach to prevent collapse of scaffold shoring system during concrete formwork. In this article, the causes of the collapse of scaffold shoring system are investigated. A monitoring system based on the Internet of Things(IoT) is then proposed, consisting of wireless sensors, wireless monitor, wireless alarm, monitoring cloud platform and mobile client. The monitoring system is then put into practical application and has successfully detected the malfunction of the monitored system, which proves the efficiency and reliability of the monitoring system.

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Fan, Zhen Zhong, Li Feng Zhang, Qing Wang Liu, Ji Gang Wang, Ning Ning Zhan und Wen Bin Zhou. „Expansion Slurry System Research“. Applied Mechanics and Materials 295-298 (Februar 2013): 3289–92. http://dx.doi.org/10.4028/www.scientific.net/amm.295-298.3289.

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In-depth development of a block of Sudan, effectively develop the rich reserves of the major reservoirs, increase crude oil production, and reduce the cost of drilling.This horizon has a high penetration, high formation temperature, easy to collapse, gas channeling and complex problem, there is a great test of this case to horizontal wells cementing.Therefore, develop a new expansion slurry system,which has the feature of high-strength, low water loss, gas channeling effect, solves the region problems of cementing technical. A block of Sudan formation pressure coefficient is low, fracture pressure is small, strata is sulfur loose sandstone, and stratigraphic diagenetic is poor, easy to collapse and necking.With the deepening of the development ,these issues are more and more obvious.In order to achieve the best results in the horizontal well cementing operations, we research from geological data, well structure, cementing formulations and process in-depth and meticulous. Solve the high permeability formation temperature, easy to collapse, gas channeling technical problems, develope a new type of high-strength, low water loss, micro-expansion slurry system, and effectively solve the block problem of horizontal wells cementing .

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ABED, E. H., H. O. WANG, J. C. ALEXANDER, A. M. A. HAMDAN und H. C. LEE. „DYNAMIC BIFURCATIONS IN A POWER SYSTEM MODEL EXHIBITING VOLTAGE COLLAPSE“. International Journal of Bifurcation and Chaos 03, Nr. 05 (Oktober 1993): 1169–76. http://dx.doi.org/10.1142/s0218127493000969.

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Dynamic bifurcations, including Hopf and period-doubling bifurcations, are found to occur in a power system dynamic model recently employed in voltage collapse studies. The occurrence of dynamic bifurcations is ascertained in a region of state and parameter space linked with the onset of voltage collapse. The work focuses on a power system model studied by Dobson & Chiang [1989]. The presence of the dynamic bifurcations, and the resulting implications for dynamic behavior, necessitate a re-examination of the role of saddle node bifurcations in the voltage collapse phenomenon. The bifurcation analysis is performed using the reactive power demand at a load bus as the bifurcation parameter. It is determined that the power system model under consideration exhibits two Hopf bifurcations in the vicinity of the saddle node bifurcation. Between the Hopf bifurcations, i.e., in the "Hopf window," period-doubling bifurcations are found to occur. Simulations are given to illustrate the various types of dynamic behaviors associated with voltage collapse for the model. In particular, it is seen that an oscillatory transient may play a role in the collapse.

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Tong, Ying-hui, Ying He, Lu-ying Hu, Yu-jia Liu, Xiao-wei Zheng, Jiao Sun, Yu Song, Yi-wen Zhang, Luo Fang und Ping Huang. „Elevated proportion of collapsed microvessels indicate poor survival outcome in patients with non-small cell lung cancer“. Tumori Journal 105, Nr. 6 (03.09.2019): 494–500. http://dx.doi.org/10.1177/0300891619871103.

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Background: An integral and well-functioning vascular system is essential for tumor progression and chemotherapy infusion. However, the lumen integrity of the microvessels and its significance in prognosis has not been studied. In this study, we found that the proportion of collapsed microvessels is suggested to be a novel biomarker for predicting prognosis in patients with non-small cell lung cancer (NSCLC). Methods: In this study, immunohistochemical CD31 staining was performed to identify the microvessels in tumor specimens. Proportions of collapsed vessels were estimated in CD31-stained tumor specimens from 100 patients with NSCLC. The correlation between collapsed microvessel proportion and survival time were evaluated by univariate and multivariate analysis. Results: Data from 99 patients were analyzed and a wide range of collapse–microvessel fraction was observed in 96 patients (1.4%–70%). Elevated collapse proportion (⩾6.5%) indicated poor overall survival in both univariate analysis ( p = 0.042) and multivariate analysis ( p = 0.014). Conclusions: Elevated proportion of collapsed microvessels indicted poor survival outcome in patients with NSCLC.

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Akbari, Amir, Reghan J. Hill und Theo G. M. van de Ven. „An elastocapillary model of wood-fibre collapse“. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 471, Nr. 2179 (Juli 2015): 20150184. http://dx.doi.org/10.1098/rspa.2015.0184.

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An elastocapillary model for drying-induced collapse is proposed. We consider a circular elastic membrane with a hole at the centre that is deformed by the capillary pressure of simply and doubly connected menisci. The membrane overlays a cylindrical cavity with rigid walls, trapping a prescribed volume of water. This geometry may be suitable for studying structural failures and stiction in micro-electromechanical systems during wet etching, where capillary surfaces experience catastrophic transitions. The dry state is determined using the dihedral-angle and volume-turning-point stability criteria. Open and collapsed conformations are predicted from the scaled hole radius, cavity aspect ratio, meniscus contact angle with the membrane and cavity walls, and an elastocapillary number measuring the membrane stretching rigidity relative to the water surface tension. For a given scaled hole radius and cavity aspect ratio, there is a critical elastocapillary number above which the system does not collapse upon drying. The critical elastocapillary number is weakly influenced by the contact angle over a wide range of the scaled hole radius, thus indicating a limitation of surface hydrophobization for controlling the dry-state conformation. The model is applied to the drying of wood fibres above the fibre saturation point, determining the conditions leading to collapse.

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