Academic literature on the topic 'Strain burst'
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Journal articles on the topic "Strain burst"
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Li, H., A. H. W. Ngan, and M. G. Wang. "Continuous Strain Bursts in Crystalline and Amorphous Metals During Plastic Deformation by Nanoindentation." Journal of Materials Research 20, no. 11 (November 2005): 3072–81. http://dx.doi.org/10.1557/jmr.2005.0379.
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Using depth-sensing indentation with sub-nanometer displacement resolution, the plastic deformation of a range of materials, including a metallic glass, amorphous selenium, Ni3Al, pure Nb, Al, Cu, and Zn metals, and an Al-Mg alloy, has been investigated at room temperature. In amorphous selenium, even the sub-nanometer displacement resolution of the nanoindentation technique cannot reveal any strain burst during deformation at room temperature. In all other metals studied, what may appear to be smooth load-displacement curves at macroscopic scale during indentation deformation in fact turn out to consist of a continuous series of random bursts of the nanometer scale. The occurrence probability of the bursts is found to decrease at increasing burst size. In all of the crystalline metals and alloys studied, the size distribution of the strain bursts seems to follow an exponential law with a characteristic length scale. The absence of the self-organized critical behavior is likely a result of the small size of the strained volume in the nanoindentation situation, which gives rise to a constraint of a characteristic strain. In the metallic glass sample, due to the limited range of the burst sizes encountered, whether the deformation bursts follow an exponential or a power-law behavior corresponding to self-organized criticality is inconclusive. From a theoretical viewpoint based on the Shannon entropy, the exponential distribution is the most likely distribution at a given mean burst size, and this is thought to be the reason for its occurrence in different materials.
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He, Manchao, Fuqiang Ren, and Cheng Cheng. "Mechanism of Strain Burst by Laboratory and Numerical Analysis." Shock and Vibration 2018 (October 23, 2018): 1–15. http://dx.doi.org/10.1155/2018/8940798.
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Strain burst is often considered to be a type of failure related to brittle rock material; therefore, many studies on strain burst focus on the brittleness of rock. However, the laboratory experiments show that strain burst can not only occur in hard brittle rock-like granite but also in the relatively ductile rock-like argillaceous sandstone. This result proves that behavior of rock material is not the only factor influencing the occurrence of strain burst. What must also be considered is the relative stiffness between the excavation wall/ore body and the surrounding rock mass. In order to further studying the mechanism of strain burst considering the whole system, the engineering geomechanial model and numerical model of strain burst due to excavation are built, respectively. In a series of numerical tests, the rock mass involving the excavation wall as well as roof and floor is biaxially loaded to the in situ stress state before one side of the excavation wall is unloaded abruptly to simulate the excavation in the field. With various system stiffness determined by the microproperties including the contact moduli of particles and parallel bond moduli in the models of roof and floor, the different failure characteristics are obtained. Based on the failure phenomenon, deformation, and released energy from the roof and floor, this study proves that the system stiffness is a key factor determining the violence of the failure, and strain burst is prone to happen when the system is soft. Two critical Young’s moduli ratios and stiffness ratios are identified to assess the violence of failure.
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Yin, Yanchun, Xingxue Tang, Qinwei Ma, Zhenan Li, and Wei Zhang. "Simulation Research on Energy Evolution and Supply Law of Rock–Coal System under the Influence of Stiffness." Sustainability 15, no. 2 (January 10, 2023): 1335. http://dx.doi.org/10.3390/su15021335.
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The energy supply effect caused by the stiffness difference between roofs and sidewalls is an important factor that induces strain coal bursts. In order to quantitatively reveal the energy supply mechanism of strain coal bursts, this paper first establishes a coal burst energy model of the rock–coal system and proposes the calculation formula of coal burst kinetic energy considering supply energy and the stiffness ratio of rock to coal. Then the whole energy evolution law of the rock–coal system with different stiffness ratios is researched by using the numerical simulation method, and the whole process is divided into three stages. With the decrease in the stiffness ratio, the elastic strain energy of the coal changes little, while its kinetic energy is negatively correlated with the stiffness ratio in a power function. Meanwhile, the elastic strain energy and kinetic energy of the rock have power function relations with the stiffness ratio, too. When the rock–coal system is fractured, the kinetic energy of the coal comes from the release of elastic strain energy from the coal and the energy supplied from the rock. The energy supply rate is between 22% and 35% when the stiffness ratio changes from 3.0 to 0.5, and they show a linear relationship, while the supplied energy has a negative power function relationship with the stiffness ratio.
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Lai, Y. H., H. M. Chen, C. J. Lee, J. C. Huang, and J. S. C. Jang. "Strain burst speeds in metallic glass micropillars." Intermetallics 18, no. 10 (October 2010): 1893–97. http://dx.doi.org/10.1016/j.intermet.2010.02.037.
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Tadmor, E. B., and D. Durban. "Plastic Deformation and Burst of Pressurized Multilayered Cylinders." Journal of Pressure Vessel Technology 117, no. 1 (February 1, 1995): 85–91. http://dx.doi.org/10.1115/1.2842096.
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A large strain analysis is presented for internally pressurized multilayered tubes, in generalized plane strain. Material behavior is modeled by an elastoplastic deformation theory with an orthotropic yield function, introduced by Hill, and arbitrary hardening. Elastic compressibility is neglected. An exact solution is given, in terms of quadratures, along with a general condition for burst. Simple yet useful relations are derived for thin-walled cylinders with the neglect of elastic strains. For rigid/nonlinear-hardening response, we obtain an expression for the onset of burst in terms of overall effective moduli. A few numerical examples are given and the possibility of locating an optimal two-layer configuration is discussed. It appears that optimization with respect to weight is attainable provided that appropriate materials are selected.
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Matemilola, S. A., and W. J. Stronge. "Low-Speed Impact Damage in Filament-Wound CFRP Composite Pressure Vessels." Journal of Pressure Vessel Technology 119, no. 4 (November 1, 1997): 435–43. http://dx.doi.org/10.1115/1.2842327.
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Quasi-static and impact tests were conducted on filament-wound carbon fiber composite pressure vessels to study factors that affect burst pressure. Observed damage included fiber microbuckling, matrix cracking, and delamination. Fiber microbuckling of the outer surface layer near the impact point was the main factor that reduced the burst pressure of the vessels. This type of damage was visually detectable on the surface. For similar levels of missile kinetic energy, the impact damage to filament-wound composite pressure vessels depends on size and shape of the colliding body in the contact area. Burst pressure for a damaged vessel decreases with the ratio of axial length of damaged fibers 1, to vessel wall thickness h, up to a ratio 1/h = 3; beyond this length of damaged section the burst pressure was independent of length of damage. Strain measurements near the region of loading showed that damage related to fiber microbuckling is sensitive to strain rate. At locations where impact damage was predominately due to fiber microbuckling, the failure strain was about six times the strain for microbuckling during quasi-static loading.
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Zhu, Hongbo, Weipu Xu, Zhiping Luo, and Hongxing Zheng. "Finite Element Analysis on the Temperature- Dependent Burst Behavior of Domed 316L Austenitic Stainless Steel Rupture Disc." Metals 10, no. 2 (February 8, 2020): 232. http://dx.doi.org/10.3390/met10020232.
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As a safety device, a rupture disc instantly bursts as a nonreclosing pressure relief component to minimize the explosion risk once the internal pressure of vessels or pipes exceeds a critical level. In this study, the influence of temperature on the ultimate burst pressure of domed rupture discs made of 316L austenitic stainless steel was experimentally investigated and assessed with finite element analysis. Experimental results showed that the ultimate burst pressure gradually reduced from 6.88 MPa to 5.24 MPa with increasing temperature from 300 K to 573 K, which are consistent with the predicted instability pressures acquired by nonlinear buckling analysis using ABAQUS software. Additionally, it was found that a gradual transition from opening ductile mode to cleavage mode happened with increasing temperature due to more cross slips occurring under serious plastic deformation. The equivalent stress, equivalent strain and strain hardening rates acquired by static analysis were effective at rationalizing the temperature-dependent fracture behavior of the domed rupture discs.
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Zhong, Kun, Wusheng Zhao, Changkun Qin, and Weizhong Chen. "Experimental Study on the Mechanical Behavior and Failure Characteristics of Layered Coal at Medium Strain Rates." Energies 14, no. 20 (October 13, 2021): 6616. http://dx.doi.org/10.3390/en14206616.
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The study of the mechanical properties and failure behaviors for coal with different bedding structures at various medium strain rates is of great importance for revealing the mechanism of rock burst. In our study, we systematically analyze the uniaxial compressive strength (UCS), acoustic emission (AE) characteristics, failure pattern, and risk of rock burst on coal specimens with two bedding orientations under ranged in strain rates from 10−4 s−1 to 10−2 s−1. The results reflect that and the bedding direction and the strain rates significantly affect the UCS and failure modes of coal specimens. The UCS of coal specimens with loading directions perpendicular to bedding planes (horizontal bedding) increases logarithmically with increasing strain rate while the UCS increases first and then decreases of coal specimens with loading directions parallel to bedding planes (vertical bedding). The AE cumulative energy of the specimens with horizontal bedding is an order of magnitude higher than that of specimens with vertical bedding. However, it is independent of the strain rates. The energy release rates of these two types of bedded coal specimens increase in a power function as the strain rate increases. The coal specimens with horizontal bedding show violent failure followed by the ejection of fragments, indicating a high risk of rock burst. On the other hand, the coal specimens with vertical bedding exhibit a tensile splitting failure with a low risk of rock burst. Strain localization is a precursor of coal failure, and the concentration area of local principal strain is highly consistent with the initial damage area, and the area where the principal strain gradient is significantly increased corresponds to the fracture initiation area.
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Zhong, Kun, Wusheng Zhao, Changkun Qin, and Weizhong Chen. "Experimental Study on the Mechanical Behavior and Failure Characteristics of Layered Coal at Medium Strain Rates." Energies 14, no. 20 (October 13, 2021): 6616. http://dx.doi.org/10.3390/en14206616.
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The study of the mechanical properties and failure behaviors for coal with different bedding structures at various medium strain rates is of great importance for revealing the mechanism of rock burst. In our study, we systematically analyze the uniaxial compressive strength (UCS), acoustic emission (AE) characteristics, failure pattern, and risk of rock burst on coal specimens with two bedding orientations under ranged in strain rates from 10−4 s−1 to 10−2 s−1. The results reflect that and the bedding direction and the strain rates significantly affect the UCS and failure modes of coal specimens. The UCS of coal specimens with loading directions perpendicular to bedding planes (horizontal bedding) increases logarithmically with increasing strain rate while the UCS increases first and then decreases of coal specimens with loading directions parallel to bedding planes (vertical bedding). The AE cumulative energy of the specimens with horizontal bedding is an order of magnitude higher than that of specimens with vertical bedding. However, it is independent of the strain rates. The energy release rates of these two types of bedded coal specimens increase in a power function as the strain rate increases. The coal specimens with horizontal bedding show violent failure followed by the ejection of fragments, indicating a high risk of rock burst. On the other hand, the coal specimens with vertical bedding exhibit a tensile splitting failure with a low risk of rock burst. Strain localization is a precursor of coal failure, and the concentration area of local principal strain is highly consistent with the initial damage area, and the area where the principal strain gradient is significantly increased corresponds to the fracture initiation area.
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Eriksen, Rasmus Skytte, and Sandeep Krishna. "Defence versus growth in a hostile world: lessons from phage and bacteria." Royal Society Open Science 7, no. 9 (September 2020): 201118. http://dx.doi.org/10.1098/rsos.201118.
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Bacterial communities are often highly diverse with several closely related species (or strains) coexisting together. These bacteria compete for resources and the competitive exclusion principle predicts that all but the fastest-growing bacteria will go extinct. When exposed to phage, it is predicted that bacterial strains with restriction–modification (RM) systems can circumvent the competitive exclusion principle and reach diversity of the order of the phage burst size. We show that with a trade-off between bacterial growth rates and the strength of their RM systems, the diversity of such an ecosystem can further increase several fold beyond the burst size limit. Moreover, we find that the ratio of the growth rate of a bacterial strain to the imperfection of its RM system is an excellent predictor of (i) whether the strain will go extinct or not, and (ii) the biomass of the strain if it survives. In contrast, the growth rate alone is not a determinant of either of these properties. Our work provides a quantitative example of a model ecosystem where the fitness of a species is determined not by growth rate, but by a trade-off between growth and defence against predators.
Dissertations / Theses on the topic "Strain burst"
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Felden, Luc. "Mechanical optimization of vascular bypass grafts." Thesis, Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-04112005-145422/unrestricted/felden%5Fluc%5F200505%5Fmast.pdf.
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Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2005.David N. Ku, Committee Chair ; Alexander Rachev, Committee Co-Chair ; Elliot L. Chaikof, Committee Member. Includes bibliographical references.
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Kopr, Radim. "Polyfunkční dům." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-392126.
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The diploma thesis deals with the design of a multifunctional house on the street Křídlovická in the city of Brno. The new building is five-storey with four above-ground and one underground floors. The main entrance is oriented to the southeastern side and adjacent to the northwest side, and a separate entrance to the underground garage in the southwest corner of the designed object. Behind the main entrance is a staircase connecting all floors, after a special entrance for the underground garage is the staircase down into the garage. From the southwest side there are entrances to restaurants and shops, these have staffing and supply entrances and social facilities from the north-east side of the building. A downhill ramp is also located behind the northeast side of the building, from the southwest side are solved areas - restaurant garden, sidewalks and parking areas. In other above-ground floors, open space office spaces with separate meeting rooms, office director, secretary offices, and social facilities on the northeastern side of the floor are designed. Within these floors is proposed continuous greening of the atrium. The supporting system is a monolithic reinforced concrete combined with masonry staircases and a northeast wall. In the basement, the support system is a skeleton in combination with the walls of a lost formwork. Roof flat single-skinned with various inclinations 1-5°
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Akdag, Selahattin. "Experimental investigation of damage evolution during strain burst in brittle rocks for deep mines." Thesis, 2019. http://hdl.handle.net/2440/120726.
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The increasing demand for resources and depletion of near ground mineral resources caused deeper mining operations under high-stress and high-temperature rock mass conditions. As a results of this, strain burst, which is the sudden and violent release of stored strain energy during dynamic brittle failure of rocks, has become more prevalent and created considerable safety risks damaging underground infrastructures. This research focuses on the development of experimental methodologies to better understand the fundamental knowledge concerning the failure mechanism of strain burst and the influence of thermal damage, high confining pressure and various loading rate on the overall mechanical behaviour of highly brittle granitic rocks leading to strain burst. Strain burst is related to the elastic stored strain energy and how this stored energy is released during the unstable spontaneous failure. Therefore, it is significant to investigate the energy state during strain burst from the viewpoint of energy theory. In this sense, circumferential strain controlled quasi-static tests on Class II rocks over a wide range of confining pressures at different heat-treatment temperatures were conducted to capture the snap-back behaviour and calculate excess strain energy that is responsible for the spontaneous instability. A new energy calculation method associated with acoustic emission (AE) was developed to express the propensity of strain burst and investigate the post-peak energy distribution characteristics for brittle rocks under the coupling influence of confinement and temperature. In order to quantify the micro-crack density and reveal the micro-fracture characteristics of the brittle rocks exposed to various temperatures, scanning electron microscopy (SEM) analysis was also conducted. This is highly relevant to link the excess strain energy and the main failure mechanism triggering strain burst under high-temperature condition. The failure process of strain burst is the outcome of the unstable growth and coalescence of secondary micro-cracks. If the dissipative energy to grow pre-existing cracks and the secondary cracks is smaller than the elastic stored strain energy in rock masses, the residual strain energy will be released suddenly in the form of kinetic energy, resulting in ejecting high-velocity rock fragments. Therefore, understanding the crack initiation and propagation in rocks is of great concern for engineering stability and security. As an intrinsic property of rocks to resist crack initiation and propagation, the rock fracture toughness is the most significant material property in fracture mechanics. In this respect, the three-point bending method was applied using cracked chevron notched semi-circular bend (CCNSCB) granite specimens subjected to different temperatures under a wide range of loading rates in pure mode I. A suitable relation for the dimensionless stress intensity factor (𝑌∗) of SCB with chevron notch samples were presented based on the normalised crack length (𝛼) and half-distance between support rollers (𝑆/2). The minimum dimensionless stress intensity factor (𝑌𝑚𝑖𝑛∗) of CCNSCB specimens were determined using an analytical method, i.e., Bluhm’s slice synthesis method. In this study, the influence of thermal damage and loading rate on the quasi-static mode I fracture toughness and the energy-release rate using CCNSCB method was investigated. In the deep mining process, the rock mass is subjected to a dynamic disturbance caused by blasting, and mechanical drilling resulting in dynamic fractures in the forms of strain burst, slabbing, and spalling. The dynamic rock fracture parameters, including dynamic initiation fracture toughness and fracture energy which are an important manifestation of dynamic rock failure (strain burst) in deep underground engineering and they are of great practical significance to assess the dynamic fracture behaviour of deep rock masses. Since deep rock engineering operations in high temperature and high pressure environment is prone to strain burst, the influence of thermally induced damage on the dynamic failure parameters of granite specimens was investigated. The damage evolution of granitic rocks were studied over a wide range of loading rates to reveal the rate dependency of strain burst. Dynamic fracture toughness tests were carried out on granite under different temperatures and impact loadings using a Split Hopkinson Pressure Bar (SHPB) apparatus at Monash University. With dynamic force balance achieved in the dynamic tests, the stable-unstable transition of the crack propagation crack was observed and the dynamic initiation fracture toughness was calculated from the dynamic peak load. The thermal damage influence on strain burst characteristics of brittle rocks under true-triaxial loading-unloading conditions was investigated using the AE and kinetic energy analyses. A unique strain burst testing system enabling to simulate the creation of excavation at the State Key Laboratory for Geomechanics and Deep Underground Engineering in Beijing (China) was used to replicate strain burst condition. Time-domain and frequency-domain responses AE waves related to strain burst were studied, and the damage evolution was quantified by b-values, cumulative AE energy and events rates that can be used as warning signals to rock failure. The ejection velocities of the rock fragments from the free face of the granite specimens were used to calculate kinetic energies which can be used as an indicator for quantitatively evaluating the intensity of strain burst. Based on the energy evolution characteristics of brittle rocks under uniaxial and triaxial compression, true-triaxial loading-unloading and three-point bending, new strain burst proneness indexes and strain burst criterion were proposed. The effects of temperature, confinement and loading rate on strain burst proneness were discussed. This study aims to advance the understanding on underlying processes that govern the macro-behaviour of brittle rocks during strain burst and make use of this insight to further advance our current predictive capabilities of strain burst with references to large-scale underground mining. Using the developed experimental methodologies in this study, fractures around an excavation to reduce the amount of excess strain energy leading to strain burst can be determined and ultimately incipient strain burst in deep mines can be predicted avoiding potential hazards. Using the methodology for forecasting of strain burst in this research can be used for enhanced understanding of the design of rock support in strain burst-prone areas in deep mining activities. The findings of this study will facilitate achieving a better and comprehensive understanding of the damage process during strain burst in deep mines. This study underpins the development of better and more efficient prediction methods for strain burst which will lead to better planning guidelines and ultimately safer deep underground working conditions.Thesis (Ph.D.) -- University of Adelaide, School of Civil, Environmental and Mining Engineering, 2019
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Verma, Rupesh Kumar. "A Combined Theoretical-Experimental-Numerical Approach to Characterization and Modelling of Rock Fracture and Rock Burst." Thesis, 2020. http://hdl.handle.net/2440/126543.
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Rock burst is a violent failure of rock in deep underground conditions, which often has severe consequences. Nevertheless, its underlying mechanism is not well understood, let alone being accurately predicted. Existing research studies do indicate the significance of strain energy storage in rock, but questions like, what material properties control strain energy characteristics? How to determine and link it with bursting? How to utilize such a framework further to unveil rock-bursting? Have always been at the center and thus formed our motivational base as well. This research presents a systematic approach to combine theoretical, experimental, and numerical developments towards a size-dependent energy-based rockburst criterion. Along this line, this research develops a new indirect tensile testing methodology named as ‘AUSBIT’ to control the dynamics due to excess strain energy storage in disc cracking under diametric compression. It allows capturing ‘Snap-Back’ behavior and determining inherent fracture, elastic, strength (tensile), and brittleness properties, all from one simple experiment. The devised methodology is patented in Australia as an Innovation Patent. A theoretical framework delineating the snap-back magnitude, which can be considered as a simple bursting indicator, is also developed. Advanced instrumentations such as Digital Image Correlation (DIC) and Acoustic Emission (AE) techniques are utilized to explore the benefits of controlled diametrical cracking and obtain further details on failure mechanism and its evolutions. This thesis also develops a hybrid numerical modeling approach based on Discrete and Finite Element Methods (3DEC, by Itasca). It incorporates a new cohesive contact model with elastoplastic-damage coupling. Laboratory experiments, including uniaxial compressive strength (UCS) and conventional Brazilian disc (BD) test, are conducted with DIC and AE applications to calibrate, validate and demonstrate the competency of the developed numerical modeling approach. At last, this research develops a size-dependent energy-based rockburst criterion linking strength, fracture energies, and specimen size effect with stress state due to changes in boundary conditions. It results in the proposal of a bursting index (₽) to quantify the bursting scale. Experimental data of Bluestone rock obtained from AUSBIT and UCS tests are utilized to illustrate the capability of the proposed theoretical framework. Virtual strain-burst experiments are conducted using the developed numerical modeling approach for verification purposes. This research also provides the links between the conclusions and results from the proposed theoretical framework with the evaluation of in-situ bursting potential in rock masses around underground openings.Thesis (Ph.D.) -- University of Adelaide, School of Civil, Environmental and Mining Engineering, 2020
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Chen, Jeng-Yan, and 陳政延. "Pathogenic bursa-derived field strain contributes to rescue cell-culture-adapted infectious bursal disease virus using RNA polymerase II reverse genetics strategy." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/89232445828738891674.
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碩士國立中興大學
微生物暨公共衛生學研究所
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Infectious bursal disease virus (IBDV) causing a highly contagious disease in young chickens is composed of non-enveloped capsid containing two segments of double stranded RNA, Segment A (3.3 kb) and Segment B (2.9 kb). Pathogenic wild-type very virulent IBDV (vvIBDV) was not easy to be adapted to cells. In previous studies, the vvIBDV-TWN strain could not be adapted to cells after six blind passages. The outer capsid VP2 has been mapped the specific amino acids Q253 and A284 that were involved in cell culture adaptation of IBDV. The objective of this study was to generate a cell-adapted IBDV using RNA polymerase II reverse genetic strategy with sequences of vvIBDV-TWN as templates. pVAX/SegA/HDR and pVAX/SegB/HDR plasmids were constructed to contain Segment A and Segment B of vvIBDV-TWN strain, respectively and a hepatitis delta virus ribozyme (HDR) was added into the 3’ end of each construct. A pVAX/mutSegA/HDR was also generated by introducing direct mutations (Q253H and A284T) into the VP2 protein. DF-I cells were transfected with various combinations of constructed plasmids with/without co-infected with bursa-derived vvIBDV one day after transfection. The obvious cytopathogenic effects (CPE) were only seen in the cells transfected with the combinations including pVAX/mutSegA/HDR and co-infected with vvIBDV. Cells with CPE had positive green immunofluorescence signals by indirect immunofluorescence with anti-IBDV polyclonal antibody. The products of RT-PCR from cells with CPE could be cut by restriction enzyme BglII which is the genetic tag in pVAX/mutSegA/HDR to distinguish recombinant virus from vvIBDV-TWN strain. The results indicated that the co-infection of pathogenic bursa-derived vvIBDV-TWN contributed to the adaptation in cell culture of IBDV generated by RNA polymerase II reverse genetics strategy in vitro.
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ŠRÁMKOVÁ, Jana. "Psychosociální zátěž osob pečujících o osoby závislé na pomoci jiné fyzické osoby v domácím prostředí." Master's thesis, 2016. http://www.nusl.cz/ntk/nusl-252226.
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This diploma thesis deals about the points at issue of the psycho-social strain with people taking care of the person dependant on the care of other physical person in the home background. The problems of family home helps in the natural millieu of an individual dependant on the care are getting more and more actual. The aim of this diploma thesis lies in defining the decisive factors of the psycho-social strain on the persons caring of persons dependant on the assistence of other physical person in the home background. The partial aim is to find out in which areas the persons taking care of persons dependant on the asistence of other physical person in the home background feel the increased strain. Another partial aim is to find out whether the persons taking care of persons dependant on the assistence of other physical person in the home background know and apply the principles of mental hygiene. Following the aims of the diploma thesis, there are postulated two research questions. The research question 1: Which kind of stress do the caring persons consider the most relevant in their job? The research question 2: Which possible symptoms of burnt-out effect do the caring persons observe on themselves? The practical part of the diploma thesis is worked out in the form of qualitative research. The method of inquiry and the technique of semi-structuralized interview were used for the purposes of the research. Furthermore, the technique of observation was applied. The research was implemented with the Inventory of symptoms of burnt-out effect adapted for the purpose of this research. The selected file is formed of eight persons taking care of persons dependant on the assistence of other physical person in the home background who complied with the pre-set criteria; the method of so-called "snowball" was chosen. The gained data were evaluated by the method of open coding. The research pointed out the facts and risks that the realization of the care of a person dependant on the care of other physical person in the home background is carrying out. The research pointed out the areas in which these persons feel the increased strain. The area of physical exertion in caring, the consciousness of responsibility in connection with caring, the area of communication and understanding a person dependant on the care and facing up to the fate and watching helplessness are demanding the most for the caring persons. It was found out from the evidences that caring persons consider this activity stressful; they feel both acute and chronical stress during the execution of the care, they feel it in connection with the lack of time and with the responsibility, in connection with the fears of future, but also in connection with not coping with the past. Family and friends, that provide both psychical support and assistence in the realization of the care, help most the persons caring of persons dependant on the care to deal with the demands of this care. As well as solitude and rest, sport activities and culture help them. In connection with caring the engaged persons have the feeling of doing a good thing, but also the feelings of sorrow, doubts and despairs. Those caring persons who perceive the risky factor of burnt-out effect can observe its symptoms on the emotional, rational, physical and social level on themselves. This thesis can contribute to understanding the importance of work of caring persons in the home background. It will deliver the information about the relevant factors of psycho-social strain on the persons taking care of persons dependant on the assistence of other physical person in the home background. Moreover, it can contribute to the eventual development of services corresponding to the needs of the persons taking care of persons dependant on the assistence of other physical person in the home background.
Books on the topic "Strain burst"
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Kaddour, A. S. Strain rate and temperature effects on the burst properties of filament wound composite tubes. Manchester: UMIST, 1992.
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Whyatt, J. K. Numerical exploration of shear-fracture-related rock bursts using a strain-softening constitutive law. Washington: U.S. Dept. of the Interior, Bureau of Mines, 1991.
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Howland, John. Hearing Luxe Pop. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199985227.003.0009.
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This chapter examines the concept of the “luxe pop” production practices and their evolution over the last several decades. It traces the connection between modern luxe pop, 1970s symphonic soul, and 1920s symphonic jazz. Each case features the timbre of a lush string orchestra as a stand-in for highbrow or elevated culture, while the overlaid genres of jazz, soul, and hip-hop function as a symbol of lowbrow culture. This juxtaposition of black/white, lowbrow/highbrow, street/luxury functions as musical irony and subversive sarcasm. This chapter traces specifically the connection between Jay-Z’s symphonic hip-hop production “Can I Live,” which samples Isaac Hayes’s cover of Burt Bacharach’s “The Look of Love,” a recording that was featured in the movie Casino Royale (1967). Pop music’s tendency to borrow samples from its own history (“retromania”) leads to an interconnected web of artists spanning decades of popular music.
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Müller-Graff, Peter-Christian, ed. Europäisches Binnenmarkt- und Wirtschaftsordnungsrecht. Nomos Verlagsgesellschaft mbH & Co. KG, 2021. http://dx.doi.org/10.5771/9783748908593.
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<b>Das Europäische Wirtschaftsordnungsrecht</b> prägt maßgeblich Inhalte und Entwicklungsrichtung des Europäischen Unionsrechts insgesamt und einen wesentlichen Teil von Neuerungen in den mitgliedstaatlichen Rechtsordnungen. Das Handbuch systematisiert und analysiert die auslegungsrelevanten Themen historisch, institutionell, funktional und judiziell. <b>Die 2. Auflage</b> bringt sämtliche Abschnitte auf den neuesten Stand, insbesondere in den wirtschaftsordnungsrechtlichen Bezügen der Währungsunion. Die aktuellen Entwicklungen im Rahmen des Aufgabenumfangs der EZB (Bankenunion, unkonventionelle Geldpolitik), die politische Debatte um eine „echte WWU“ (EU-Währungsfonds, -Finanzminister), die aktuellen Austrittszenarien Großbritanniens („Brexit“, Austrittsvertrag) sind ebenso wie z.B. die neue MarkenrechtsRL und die neue UnionsmarkenVO berücksichtigt. <b>Die Themen im Einzelnen:</b> Das Binnenmarktrecht der transnationalen Faktorfreiheiten Das Binnenmarktrecht der transnationalen Produktfreiheiten Das Binnenmarktrecht gegen Wettbewerbsbeschränkungen Das Binnenmarktrecht gegen unlauteren Wettbewerb Das Binnenmarktrecht der Aufsicht über wettbewerbsverfälschende staatliche Beihilfen Das Binnenmarktrecht des öffentlichen Auftragswesens Das Binnenmarktrecht des geistigen Eigentums (gewerblicher Rechtsschutz und Urheberrecht) Das Binnenmarktrecht der wirtschaftlichen Regulierung Das Binnenmarktrecht der Krisen von Unternehmen und Wirtschaft Das Recht der Europäischen Wirtschafts- und Währungsunion Die <b>prägende Rechtsprechung </b>der europäischen Gerichte und des Bundesverfassungsgerichts ist ausführlich dargestellt. <b>Die Autorinnen und Autoren</b> Dr. Rainer Becker, LL.M.; RAin Dr. Barbara Bonk; Prof. Dr. Friedrich Wenzel Bulst, LL.M.; Prof. Dr. Marc Bungenberg, LL.M.; Prof. Dr. Andreas Fuchs, LL.M.; PD Dr. Roman Guski, LL.M.; ORR Mara Hellstern; RA Dr. Jens Hoffmann;| Prof. Dr. Ulrich Hufeld; RAin Sinziana Ianc; Prof. Dr. Friedemann Kainer; Prof. Dr. Andreas Kellerhals, LL.M., S.J.D.; Prof. Dr. Michael Kling; RA Dr. Simon Klopschinski; Prof. Dr. Christian Koenig, LL.M.; Prof. Dr. Sebastian Krebber, LL.M.; Prof. Dr. Jürgen Kühling, LL.M.; RA Prof. Dr. Michael Loschelder; Prof. Dr. Julia Lübke, LL.M.; Prof. Dr. Cornelia Manger-Nestler, LL.M.; Prof. Dr. Dr. h.c. mult. Peter-Christian Müller-Graff, Ph.D. h.c.; RA Dr. Ralph Nack; Dr. Stephanie Nitsch; Prof. Dr. Walter Obwexer; Prof. Dr. Helmut Ofner, LL.M.; Dr. René Repasi; Prof. Dr. Florian Schuhmacher, LL.M.; Prof. Dr. Heike Schweitzer, LL.M.; RA Dr. Ulrich Soltész, LL.M.; Prof. Dr. Dres. h.c. Joseph Straus; Prof. Dr. Cordula Stumpf; Dr. Wesselina Uebe; Prof. Dr. Frank Weiler; RA Prof. Dr. Andreas Weitbrecht, LL.M.; Hendrik M. Wendland, LL.M.
Book chapters on the topic "Strain burst"
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Ohmura, Takahito. "Nanomechanical Characterization of Metallic Materials." In The Plaston Concept, 157–95. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-7715-1_8.
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AbstractMechanical behavior of metallic materials on nanoscale is characterized by using Nanoindentation and Transmission Electron Microscope (TEM) to understand the fundamental plasticity mechanisms associated with microstructural factors including dislocations. The advanced characterization techniques enable us to grasp the behavior on the nanoscale in detail. New knowledges are obtained for the plasticity initiation under the extremely high stress close to the theoretical strength in regions with defect-free matrix and pre-existing defects such as grain boundaries, in-solution elements, and dislocations. The grain boundaries act as an effective dislocation source, the in-solution elements retard a nucleation of dislocation, and the pre-existing dislocations assist a plasticity initiation. The deformation behavior associated with microstructures is also described. The dislocation structure with a certain density was observed right after indentation-induced strain burst, which is so-called “pop-in,” suggesting a dislocation avalanche upon the pop-in. It has been directly observed that the lower mobility screw dislocation causes the higher flow stress in a bcc metal. A remarkable strain softening can be understood by an increase in dislocation density based on conventional physical models. Phase stability for indentation-induced transformation depends on a constraint effect by inter-phase boundary and grain boundary.
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Neumann, P. "Strain Bursts in Fatigue Experiments." In Patterns, Defects and Microstructures in Nonequilibrium Systems, 270–86. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3559-4_16.
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"strain burst." In Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik, 1318. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-41714-6_197632.
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Trivedi, Vishal, Vinod Nautiyal, and Retno Widyowati. "Risk Factors of Covid-19 Enhancing Transmission and Aggravating Patient’s Condition." In Herbal Immunity Boosters Against COVID-19, 70–109. BENTHAM SCIENCE PUBLISHERS, 2022. http://dx.doi.org/10.2174/9789815079456122010006.
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For the last couple of years, novel coronavirus or SAR-CoV-2 is a severe threat to the world. This new strain of coronavirus emerged on 14th December 2020 and has been infecting many parts of the population around the world to date. These viral spikes will bind with the angiotensin-converting enzymes. Many clinical studies conducted have highlighted the association between cardiovascular diseases and COVID-19. It increases the mortality rate, the risk of injury in myocardial, acute coronary syndromes and thromboembolism. COVID-19 has produced some risk factors such as age and gender as well as comorbidities. Coronavirus may pose several challenges for oncology patients. Among cancer patients, severe respiratory and systemic infection are evident specifically among immunosuppressed and ageing patients. Cancer is said to worsen due to COVID-19 as it is linked with inflammatory burst and lymphopenia. This study has discussed the risk factors in COVID-19 transmission, factors that can aggravate it and clinical interactions between the cardiovascular system. Furthermore, several drugs that have been administered against the virus are believed to affect the patients.
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Zhu, S. J., Z. A. Yang, and Z. G. Wang. "Strain Bursts in Cyclic Creep of an Al–Mg alloy at an intermediate temperature." In Mechanical Behaviour of Materials VI, 161–66. Elsevier, 1992. http://dx.doi.org/10.1016/b978-0-08-037890-9.50145-9.
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O’Connor, Kevin. "Corruption and Socio-Political Tensions in Christine Longford’s Tankardstown (1948)." In The Golden Thread, 223–32. Liverpool University Press, 2021. http://dx.doi.org/10.3828/liverpool/9781800859463.003.0017.
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Tankardstown or A Lot to be Thankful For (1948) is Christine Longford’s best loved and most successful play. The play is a satire on the attitudes of the Irish nouveau riche counterpointed with the uptight conservatism of the old, landed gentry and the “anthropological gaze” of English visitors to Ireland. Longford’s piercing observations regarding 1940s Ireland include bracing reflections on the nation’s troubled relationships with financial and political corruption. She predicts a future boom/bust economy fueled by local greed and opportunism, thereby displaying an acute awareness of how cynical “cute hoorism” weaves its pervasive influence through all strata of Irish society. To strengthen this contention, the chapter demonstrates that the commercial and political actions undertaken by the character of Mr. Manifold can be compared to the activities of later politicians such as Charles Haughey, Albert Reynolds, Bertie Ahern, Michael Lowry and the Healy-Raes.
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"Women Pioneers in Civil Engineering and Architecture in Italy: Emma Strada and Ada Bursi." In Women's Creativity. ZRC SAZU, Založba ZRC, 2018. http://dx.doi.org/10.3986/wocrea.1.momowo1.04.
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Franchini, Caterina. "Women Pioneers in Civil Engineering and Architecture in Italy: Emma Strada and Ada Bursi." In MoMoWo: Women Designers, Craftswomen, Architects and Engineers between 1918 and 1945, 82–101. Zalozba ZRC, 2017. http://dx.doi.org/10.3986/wocrea/1/momowo1.04.
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Zalasiewicz, Jan, and Mark Williams. "The Glacial World." In The Goldilocks Planet. Oxford University Press, 2012. http://dx.doi.org/10.1093/oso/9780199593576.003.0014.
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It is a scene of devastation, as far as the eye can see. Swathes of bleak landscape, with strewn boulders embedded in a sticky mass of sandy clay. Here and there are signs of a little more order—distinct spreads of gravel or patches of fine sand. Mostly, though, it looks as though every type of sediment, from fine clay to house-sized blocks, has simply been stirred together and spread across the land. Remove the crops and topsoil of gentle Leicestershire and Suffolk, or of central Germany or Kansas, and this is what lies beneath. Between the ordered sedimentary strata of the distant geological past and the ordered calm of the present is evidence of an only-just-elapsed catastrophe, and two centuries ago, when the science of the Earth was young, the naturalists of those days pondered on what it might mean. There were those like the young William Buckland, both Reader in mineralogy at Oxford and priest (he went on to become Dean of Westminster), who saw in it evidence of the biblical Deluge. Or Jean André de Luc, mentor to the wife of George III, who considered that the large blocks had been fired, like Roman ballista, from the mountains by some powerful but mysterious explosions. Or Sir James Hall, a savant of Edinburgh, who thought that the blocks had been carried into position by tsunamis, generated when large areas of sea floor (he supposed) suddenly popped up like blisters—he was clearly of an intellectually playful disposition. Or Leopold von Buch, who invoked catastrophic mudflows (one such, indeed, did take place in an Alpine valley, the Val de Bagnes, just after von Buch’s paper on this topic was published, when a natural dam burst, scattering mud and boulders far down the valley, and killing many people). But it was that extraordinary polymath, Johann Wolfgang von Goethe (a one-time Superintendent of Mines, if you please) who was among the first to sense what had been going on, when he associated the scattered blocks with a great expansion of the Alpine glaciers he was familiar with, and coined the term Eiszeit —the Ice Age.
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Zalasiewicz, Jan, and Mark Williams. "Earth as a Snowball." In The Goldilocks Planet. Oxford University Press, 2012. http://dx.doi.org/10.1093/oso/9780199593576.003.0008.
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Our attempts to reconstruct the climate of the distant Archaean in Chapter 1 might seem a little like reading a volume of Tolstoy’s War and Peace recovered from a burnt-out house. Most of the pages have turned to ash, and only some scattered sentences remain on a few charred pages. The Proterozoic Eon that followed began 2.5 billion years ago, thus is not quite so distant from us in time. We know it a little better than the Archaean—at least a handful of pages from its own book have survived. And this book is long—the Proterozoic lasted nearly two billion years. This is as long as the Hadean and Archaean together, and not far short of half of Earth’s history. Like many a soldier’s account of war, it combined long periods of boredom and brief intervals of terror—or their climatic equivalents, at least. The latter included the most intense glaciations that ever spread across the Earth. Some of these may have converted the planet into one giant snowball. The earliest traces of glaciation on Earth are seen even before the Proterozoic, in rock strata of Archaean age, 2.9 billion years old, near the small South African town of Pongola. These rocks include sedimentary deposits called tillites, which are essentially a jumble of rock fragments embedded in finer sediment. The vivid, old-fashioned term for such deposits is ‘boulder clays’, while the newer and more formal name is ‘till’ for a recent deposit and ‘tillite’ for the hardened, ancient version. Many of the ancient blocks and boulders in the tillites of Pongola are grooved and scratched—a tell-tale sign that they have been dragged along the ground by debris-rich ice. This kind of evidence is among the first ever employed by scientists of the mid-nineteenth century, such as Louis Agassiz and William Buckland, to tell apart ice-transported sediments from superficially similar ones that had formed as boulder-rich slurries when rivers flooded or volcanoes erupted. Ice, then, appeared on Earth in Archaean times.
Conference papers on the topic "Strain burst"
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Zhou, Honggang, Yong-Yi Wang, and Steve Nanney. "Burst Pressure of Wrinkles Under High Longitudinal Strain." In 2018 12th International Pipeline Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/ipc2018-78804.
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Wrinkles may form in pipelines experiencing high longitudinal strains in areas of ground movement and seismic activities. Current assessment procedures for wrinkles were developed and validated under the assumption that the predominant loading was internal pressure and that the level of longitudinal strain was low. The impact of wrinkles on the burst pressure of pipes under high longitudinal strain is not known. This paper describes work funded by US DOT PHMSA on the assessment of burst pressure of wrinkled pipes under high longitudinal strain. Both numerical analyses and full-scale tests were conducted to examine the burst pressure of wrinkled pipes. The numerical analysis results were compared with the full-scale test data. The effect of wrinkles on burst pressure were discussed. The biaxial loading conditions in the pipe were found affect the burst pressure of wrinkled pipes.
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Zhou, Honggang, Yong-Yi Wang, Mark Stephens, Jason Bergman, and Steve Nanney. "Burst Pressure of Pipelines With Corrosion Anomalies Under High Longitudinal Strains." In 2018 12th International Pipeline Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/ipc2018-78803.
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Existing corrosion assessment models were developed and validated under the assumption that internal pressure was the principal driver for burst failure and that longitudinal strain levels were low. The impact of moderate to high levels of longitudinal strain on burst capacity had not been explicitly considered. This paper summarizes work performed as part of a major effort funded by the US Department of Transportation Pipeline and Hazardous Materials Safety Administration (DOT PHMSA) aimed at examining the impact of longitudinal strain on the integrity of pipelines with corrosion anomalies. This paper focuses on the burst pressure of corroded pipes under high longitudinal strains. It is known that longitudinal tensile strain does not reduce the burst pressure relative to that of pipes subjected to low longitudinal strains. Therefore, existing burst pressure models can be considered adequate when the longitudinal strain is tensile. However, longitudinal compressive strain was found to lead to a moderate reduction in burst pressure. Numerical analyses were conducted to study the effect of longitudinal compressive strain on the burst pressure of corroded pipes. A burst pressure reduction formula was developed as a function of the longitudinal compressive strain. Full-scale tests were conducted to confirm the findings of the numerical analysis. Guidelines for assessing the burst pressure of corroded pipes under high longitudinal compressive strains were developed from the outcome of numerical analysis and experimental tests. The guidelines are applicable to different types of corrosion anomalies, including circumferential grooves, longitudinal grooves and general corrosion.
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Rudra Goud, M., C. Manjunatha, M. Venkateshwarlu, and B. V. A. Patnaik. "Finite Element Analysis for Prediction of Permanent Growth of Rotating Disc of Aero Engine During Over-Speed and Burst-Speed Conditions and Validation of Results Through Experiment." In ASME 2013 Gas Turbine India Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gtindia2013-3625.
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The service life of critical aerospace components is governed by the modes of degradation and failure such as: yielding, fatigue, fracture, creep, corrosion, wear, etc. A single disc is used for over-speed and burst-speed tests to know the growths (plastic deformation). In this paper, a cyclic symmetry sector of disc model with non linear elastic-plastic material is considered. A non-linear finite element method is utilized to determine the stress and strain state of the disc under over-speed and burst-speed conditions using material stress strain curves. Permanent growths and strains obtained from the over-speed analysis are incorporated in the burst-speed Finite element Model. The original stress strain curve used in over-speed analysis is modified with plastic strain and used in burst-speed analysis of same disc. Elastic strains obtained from the over-speed and burst-speed analysis are utilized in stress strain relationship equations to calculate the permanent growths at critical locations of disc. Growths predicted from Analysis are comparable with the experimental results of disc where a maximum variation of 11% at bore and rim of disc is observed.
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Langrana, Noshir A., Robert D. Harten, David C. Lin, Mitchell F. Reiter, and Casey K. Lee. "Fracture Patterns and Strain Information in Thoracolumbar Burst Fractures." In ASME 2000 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/imece2000-2584.
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Abstract A combined loading of axial compression and anterior shear on a spinal motion segment causes the severe form of burst fracture. Thoracolumbar motion segments were instrumented with a strain gage on the middle of the anterior wall and one near the base of the pedicles. Two samples were subjected to high-speed axial compression in the neutral position while two were tested in extension to maximize facet joint loading. The specimens tested in extension exhibited the more severe fracture pattern, indicated by failure of the middle column and an increase in interpedicular distance. Failure loads and ratio of strain at the base of the pedicles to strain at the anterior wall were higher in this group. The results suggest that the shear force transmitted through the facet joint and the pedicles to the posterior upper half of the vertebral body is an essential component of the injury mechanism.
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Lance, Blake W., and Matthew D. Carlson. "Compact Heat Exchanger Semi-Circular Header Burst Pressure and Strain Validation." In ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/gt2019-91772.
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Abstract Compact heat exchangers for supercritical CO2 (sCO2) service are often designed with external, semi-circular headers. Their design is governed by the ASME Boiler & Pressure Vessel Code (BPVC) whose equations were typically derived by following Castigliano’s Theorems. However, there are no known validation experiments to support their claims of pressure rating or burst pressure predictions nor is there much information about how and where failures occur. This work includes high pressure bursting of three semi-circular header prototypes for the validation of three aspects: (1) burst pressure predictions from the BPVC, (2) strain predictions from Finite Element Analysis (FEA), and (3) deformation from FEA. The header prototypes were designed with geometry and weld specifications from the BPVC Section VIII Division 1, a design pressure typical of sCO2 service of 3,900 psi (26.9 MPa), and were built with 316 SS. Repeating the test in triplicate allows for greater confidence in the experimental results and enables data averaging. Burst pressure predictions are compared with experimental results for accuracy assessment. The prototypes are analyzed to understand their failure mechanism and locations. Experimental strain and deformation measurements were obtained optically with Digital Image Correlation (DIC). This technique allows strain to be measured in two dimensions and even allows for deformation measurements, all without contacting the prototype. Eight cameras are used for full coverage of both headers on the prototypes. The rich data from this technique are an excellent validation source for FEA strain and deformation predictions. Experimental data and simulation predictions are compared to assess simulation accuracy.
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Baxter, Carl, Andrew Sherry, David O’Gara, and David Beardsmore. "Strain Limits for High Strength Riser Materials." In ASME 2004 23rd International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/omae2004-51332.
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High strength materials are being used to increase the capability of dynamic risers to withstand deep water and high pressure flows. Design codes generally require that these materials operate well within their ultimate capability in the main body of the riser, but components of the riser such as screwed connectors and flanges often experience high localized or secondary stresses above yield. These stresses are allowable because they are self-limiting or in strain controlled situations. In addition the main body of the riser may also exceed yield in survival conditions when the riser may be allowed to undergo permanent distortion, but not fracture. However, high strength materials often exhibit lower ductility than traditional steels and as a result, there is a need to understand how these materials behave under high multiaxial stress conditions in order to quantify the true margin of safety in the component. The work reported in this paper focuses on titanium Grade 29, which has been used for tapered stress joints on steel catenary risers, and is now being considered for use in the riser touch down zone on several deepwater projects. The work on burst testing was also part of the validation of Dn V-RP-201, “Design of Titanium Risers”. This paper explores two approaches to determining a material model for failure. The first method used the Rice and Tracy void fraction model but this was found to be geometry dependent for this material and not ideal for failure prediction. A method was developed for determining strain limits under triaxial loading conditions using diffuse necking theory. The theory was applied to burst tests of high-pressure cylinders and gave a good prediction of the burst pressure and strain at failure.
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Zhu, Xian-Kui, and Brian N. Leis. "Theoretical and Numerical Predictions of Burst Pressure of Pipelines." In ASME 2006 Pressure Vessels and Piping/ICPVT-11 Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/pvp2006-icpvt-11-93208.
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It is known that the Tresca yield theory predicts a lower bound of burst pressure, whereas the von Mises yield theory provides an upper bound of burst pressure of pipelines. To accurately predict the burst pressure, the present authors [1] recently developed a new multiaxial yield theory for isotropic hardening materials, based on an average shear stress criterion (ASSC). Extensive classic experiments showed that the ASSC criterion can well correlate the stress-strain relations for both initial yield and subsequent yield states. Based on the ASSC yield theory, a new theoretical solution of the burst pressure of pipelines at plastic collapse is developed as a function of pipe geometry, material hardening exponent, and ultimate tensile strength. This solution is then validated by experimental data for various pipeline steels. The ASSC yield theory is further applied to accurately determine actual burst pressure using available finite element software like ABAQUS, which currently adopts the von Mises yield criterion and the associate flow rule for isotropic elastic-plastic analysis. Four burst failure criteria: the Mises equivalent stress criterion, the maximum principal stress criterion, the Mises equivalent strain criterion and the maximum tensile strain criterion are developed as functions of the ultimate tensile stress and the strain hardening exponent. Application demonstrates that the proposed failure criteria in conjunction with ABAQUS numerical analysis can accurately determine burst pressure of pipelines.
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Li, Huihui, Kaiming Wang, Chuncheng Zhang, Weiguo Wang, and Guoguang Chen. "Prediction of Rotor Burst Using Strain-Based Fracture Criteria to Comply With the Engine Airworthiness Regulation." In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-16259.
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Abstract Relative to the rotor overspeed compliance governed by civil aviation airworthiness regulation, nowadays Area-Average Stress method is commonly used approach. However, in order to effectively apply the Area-Average Stress method in analyzing burst speed, large amount of testing data is needed to define an important element of this method: a correction factor. This prerequisite hinders the use of this method for many companies which have limited test data. Meanwhile, analysis of rotor burst speed based on Strain-based Fracture Criteria using true stress-strain curves and burst tests has been done on the LPT rotor, and a work procedure obtaining the most critical burst speed for certification is proposed. The analysis results, which had a good correlation with test results, showed that Strain-based Fracture Criteria can accurately predict the burst speed considering the most adverse combination of dimensional tolerances, temperature, and material properties, and rotor dimensional growth under the overspeed condition. Both are required by the aircraft engine airworthiness overspeed regulation. Compared to the Area-Average Stress method, Strain-based Fracture Criteria reflects the physical essence of the rotor burst more realistically and can be simply verified without requiring too much test data, therefore it has a good application prospect in the aircraft engine airworthiness.
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Aihara, Shuji, Kazuki Shibanuma, Yasuhito Imai, Taishi Fujishiro, and Takuya Hara. "Evaluation on Dependence of Ductile Crack Propagation Resistance on Crack Velocity." In 2012 9th International Pipeline Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/ipc2012-90637.
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Plastic strains were measured near a propagating ductile crack in drop-weight tear tests (DWTT). Plastic work evaluated from the plastic strains agreed with crack propagation energy evaluated from dynamic load versus displacement curve. Furthermore, plastic strains were measured near a propagating ductile crack in a full-scale burst tested pipes. Plastic work of the burst pipe was found to be much larger than that of the DWTT. Values of the plastic work of the DWTT and the burst pipe were plotted against crack velocity to construct crack resistance curve. Reason to the increased crack resistance with crack velocity was understood as a dependence of plastic strain distribution on crack velocity by elasto-plastic dymanic finite element analysis.
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Okhrimchuk, Andrey, Sergey Fedotov, Ivan Glebov, Vladimir Sigaev, and Peter Kazansky. "Laser writing with sub-nanosecond burst of femtosecond pulses using strain accumulation." In 2017 Conference on Lasers and Electro-Optics Europe (CLEO/Europe) & European Quantum Electronics Conference (EQEC). IEEE, 2017. http://dx.doi.org/10.1109/cleoe-eqec.2017.8087228.
Full textReports on the topic "Strain burst"
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Papanikolaou, S., D. M. Dimiduk, W. Choi, J. P. Sethna, M. D. Uchic, C. F. Woodward, and S. Zapperi. Quasiperiodic Strain Bursts and Self-Organization in Crystal Microplasticity (PREPRINT). Fort Belvoir, VA: Defense Technical Information Center, March 2012. http://dx.doi.org/10.21236/ada559100.
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Droby, Samir, Michael Wisniewski, Ron Porat, and Dumitru Macarisin. Role of Reactive Oxygen Species (ROS) in Tritrophic Interactions in Postharvest Biocontrol Systems. United States Department of Agriculture, December 2012. http://dx.doi.org/10.32747/2012.7594390.bard.
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To elucidate the role of ROS in the tri-trophic interactions in postharvest biocontrol systems a detailed molecular and biochemical investigation was undertaken. The application of the yeast biocontrol agent Metschnikowia fructicola, microarray analysis was performed on grapefruit surface wounds using an Affymetrix Citrus GeneChip. the data indicated that 1007 putative unigenes showed significant expression changes following wounding and yeast application relative to wounded controls. The expression of the genes encoding Respiratory burst oxidase (Rbo), mitogen-activated protein kinase (MAPK) and mitogen-activated protein kinase kinase (MAPKK), G-proteins, chitinase (CHI), phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS) and 4-coumarate-CoA ligase (4CL). In contrast, three genes, peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT), were down-regulated in grapefruit peel tissue treated with yeast cells. The yeast antagonists, Metschnikowia fructicola (strain 277) and Candida oleophila (strain 182) generate relatively high levels of super oxide anion (O2−) following its interaction with wounded fruit surface. Using laser scanning confocal microscopy we observed that the application of M. fructicola and C. oleophila into citrus and apple fruit wounds correlated with an increase in H2O2 accumulation in host tissue. The present data, together with our earlier discovery of the importance of H₂O₂ production in the defense response of citrus flavedo to postharvest pathogens, indicate that the yeast-induced oxidative response in fruit exocarp may be associated with the ability of specific yeast species to serve as biocontrol agents for the management of postharvest diseases. Effect of ROS on yeast cells was also studied. Pretreatment of the yeast, Candida oleophila, with 5 mM H₂O₂ for 30 min (sublethal) increased yeast tolerance to subsequent lethal levels of oxidative stress (50 mM H₂O₂), high temperature (40 °C), and low pH (pH 4). Suppression subtractive hybridization analysis was used to identify genes expressed in yeast in response to sublethal oxidative stress. Transcript levels were confirmed using semi quantitative reverse transcription-PCR. Seven antioxidant genes were up regulated. Pretreatment of the yeast antagonist Candida oleophila with glycine betaine (GB) increases oxidative stress tolerance in the microenvironment of apple wounds. ROS production is greater when yeast antagonists used as biocontrol agents are applied in the wounds. Compared to untreated control yeast cells, GB-treated cells recovered from the oxidative stress environment of apple wounds exhibited less accumulation of ROS and lower levels of oxidative damage to cellular proteins and lipids. Additionally, GB-treated yeast exhibited greater biocontrol activity against Penicillium expansum and Botrytis cinerea, and faster growth in wounds of apple fruits compared to untreated yeast. The expression of major antioxidant genes, including peroxisomal catalase, peroxiredoxin TSA1, and glutathione peroxidase was elevated in the yeast by GB treatment. A mild heat shock (HS) pretreatment (30 min at 40 1C) improved the tolerance of M. fructicola to subsequent high temperature (45 1C, 20–30 min) and oxidative stress (0.4 mol-¹) hydrogen peroxide, 20–60 min). HS-treated yeast cells showed less accumulation of reactive oxygen species (ROS) than non-treated cells in response to both stresses. Additionally, HS-treated yeast exhibited significantly greater (P≥0.0001) biocontrol activity against Penicillium expansum and a significantly faster (Po0.0001) growth rate in wounds of apple fruits stored at 25 1C compared with the performance of untreated yeast cells. Transcription of a trehalose-6-phosphate synthase gene (TPS1) was up regulated in response to HS and trehalose content also increased.