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1
Zhang, Bo, Lian Jin Tao, Wen Pei Wang, and Ji Dong Li. "Research on the Vibration Attenuation Rules and Wave Propagation Law under Impacting Drill on the Deep Soil Layer." Advanced Materials Research 250-253 (May 2011): 1971–77. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.1971.
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A field test is carried out to study the effect of vibration while treating foundation using vibroflotation method in the deep soil layer in Zhengzhou, China. The vibration attenuation rules and wave propagation rules in different formations caused by different numbers of drills are analyzed. Evaluate the influence on the adjacent buildings. The result shows that the vibration will be generated in foundation obviously in the process of construction using the method. Vibration force, impact frequency and site soil are important influence factors on ground vibration attenuation. The analysis reveals that the maximum vertical acceleration attenuation velocity was much greater in near area than that in the relative far area. The waves caused by vibration propagate in two ways: (1) surface wave is generated on the wall of drill hole and propagated to the ground surface, and attenuated in a certain distance (<8m); (2) shear wave was generated and propagated in the impacting formation and attenuated from the deep formation to the ground surface. Vibration amplitude is mainly distributed in the low frequency range in the areas which far away from vibration source and in the silt layer near the ground surface.
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Das, Nirmali Prabha, Dorina G. Dobó, Dániel Berkesi, Ákos Kukovecz, Dezső Horváth, and Ágota Tóth. "Directional coupling in spatially distributed nanoreactors." RSC Advances 9, no. 69 (2019): 40745–49. http://dx.doi.org/10.1039/c9ra09758a.
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Perez-Mongiovi, D., P. Chang, and E. Houliston. "A propagated wave of MPF activation accompanies surface contraction waves at first mitosis in Xenopus." Journal of Cell Science 111, no. 3 (February 1, 1998): 385–93. http://dx.doi.org/10.1242/jcs.111.3.385.
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During the period of mitosis, two surface contraction waves (SCWs) progress from the animal to vegetal poles of the Xenopus egg. It has been shown that these SCWs occur in parallel with the activation of MPF and with its subsequent inactivation in the animal and vegetal hemispheres, suggesting that they are responses to propagated waves of MPF activity across the egg. We have analysed the mechanism of MPF regulation in different regions of the egg in detail in relation to SCW progression. The distributions of histone HI kinase activity and of Cdc2 and cyclin B (the catalytic and regulatory subunits of MPF) were followed by dissection of intact eggs following freezing and in cultured fragments separated by ligation. Cdc2 was found to be distributed evenly throughout the egg cytoplasm. Loss of phosphorylated (inactive) forms of Cdc2 coincided spatially with the wave of MPF activation, while cyclin B2 accumulation occurred in parallel in animal and vegetal regions. In ligated vegetal pole fragments no MPF activation or Cdc2 dephosphorylation were detectable. A wave of cyclin B destruction that occurred in concert with the second SCW was also blocked. Taken together these results indicate that the triggering mechanism for MPF activation requires components specific to the animal cytoplasm, acting via Cdc2 dephosphorylation, and that MPF activation subsequently propagates autocatalytically across the egg. SCW progression in the vegetal hemisphere was followed directly by time-lapse videomicroscopy of subcortical mitochondrial islands. The first SCW traversed the vegetal pole at the time of MPF activation in this region. Like MPF activation and inactivation, SCWs were blocked in the vegetal region by ligation. These observations reinforce the hypothesis that the first SCW is a direct consequence of the MPF activation wave. It may reflect depolymerisation of the subcortical microtubule network since it coincided exactly with the arrest of the microtubule-dependent movement of ‘cortical rotation’ and was related in direction in most eggs. The cyclin B destruction wave and associated cortical contraction of the second SCW may be localised downstream consequences of the MPF activation wave, or they may propagate independently from the animal cytoplasm.
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Rodríguez-Ocampo, Paola E., Jassiel V. H. Fontes, Michael Ring, Edgar Mendoza, and Rodolfo Silva. "A CFD Numerical Study to Evaluate the Effect of Deck Roughness and Length on Shipping Water Loading." Water 13, no. 15 (July 29, 2021): 2063. http://dx.doi.org/10.3390/w13152063.
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Shipping water events that propagate over the decks of marine structures can generate significant loads on them. As the configuration of the structure may affect the loading behaviour, investigation of shipping water loads in different structural conditions is required. This paper presents a numerical investigation of the effect of deck roughness and deck length on vertical and horizontal loads caused by shipping water on a fixed structure. Systematic analyses were carried out of isolated shipping water events generated with the wet dam-break method and simulated with OpenFoam Computational Fluid Dynamics toolbox. The numerical approach was validated and then the shipping water loads were examined. It was found that, as roughness increased, the maximum vertical and horizontal loads showed a delay. As the deck length reduced, the vertical backflow loads tended to increase. These results suggest it may be worthwhile examining the behaviour of shipping water as it propagates over rough surfaces caused by fouling, corrosion, or those with small structural elements distributed on them. Moreover, the effect of deck length is important in understanding the order of magnitude of loads on structures with variable deck lengths, and those which have forward and backflow loading stages.
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Kimura, K., K. I. Inoue, Y. Kuroiwa, F. Tanaka, and M. Takada. "Propagated but topologically distributed forebrain neurons expressing alpha-synuclein in aged macaques." Journal of the Neurological Sciences 381 (October 2017): 179. http://dx.doi.org/10.1016/j.jns.2017.08.518.
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Kimura, Katsuo, Ken-ichi Inoue, Yoshiyuki Kuroiwa, Fumiaki Tanaka, and Masahiko Takada. "Propagated but Topologically Distributed Forebrain Neurons Expressing Alpha-Synuclein in Aged Macaques." PLOS ONE 11, no. 11 (November 18, 2016): e0166861. http://dx.doi.org/10.1371/journal.pone.0166861.
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Jetti, Harsha Vardhana, and Simona Salicone. "A Possibilistic Kalman Filter for the Reduction of the Final Measurement Uncertainty, in Presence of Unknown Systematic Errors." Metrology 1, no. 1 (August 17, 2021): 39–51. http://dx.doi.org/10.3390/metrology1010003.
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A Kalman filter is a concept that has been in existence for decades now and it is widely used in numerous areas. It provides a prediction of the system states as well as the uncertainty associated to it. The original Kalman filter can not propagate uncertainty in a correct way when the variables are not distributed normally or when there is a correlation in the measurements or when there is a systematic error in the measurements. For these reasons, there have been numerous variations of the original Kalman filter, most of them mathematically based (like the original one) on the theory of probability. Some of the variations indeed introduce some improvements, but without being completely successful. To deal with these problems, more recently, Kalman filters have also been defined using random-fuzzy variables (RFVs). These filters are capable of also propagating distributions that are not normal and propagating systematic contributions to uncertainty, thus providing the overall measurement uncertainty associated to the state predictions. In this paper, the authors make another step forward, by defining a possibilistic Kalman filter using random-fuzzy variables which not only considers and propagates both random and systematic contributions to uncertainty, but also reduces the overall uncertainty associated to the state predictions by compensating for the unknown residual systematic contributions.
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Wu, Si, Danmei Chen, Mahesan Niranjan, and Shun-ichi Amari. "Sequential Bayesian Decoding with a Population of Neurons." Neural Computation 15, no. 5 (May 1, 2003): 993–1012. http://dx.doi.org/10.1162/089976603765202631.
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Population coding is a simplified model of distributed information processing in the brain. This study investigates the performance and implementation of a sequential Bayesian decoding (SBD) paradigm in the framework of population coding. In the first step of decoding, when no prior knowledge is available, maximum likelihood inference is used; the result forms the prior knowledge of stimulus for the second step of decoding. Estimates are propagated sequentially to apply maximum a posteriori (MAP) decoding in which prior knowledge for any step is taken from estimates from the previous step. Not only do we analyze the performance of SBD, obtaining the optimal form of prior knowledge that achieves the best estimation result, but we also investigate its possible biological realization, in the sense that all operations are performed by the dynamics of a recurrent network. In order to achieve MAP, a crucial point is to identify a mechanism that propagates prior knowledge. We find that this could be achieved by short-term adaptation of network weights according to the Hebbian learning rule. Simulation results on both constant and time-varying stimulus support the analysis.
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Butz, Martin V., Martin Pelikan, Xavier Llorà, and David E. Goldberg. "Automated Global Structure Extraction for Effective Local Building Block Processing in XCS." Evolutionary Computation 14, no. 3 (September 2006): 345–80. http://dx.doi.org/10.1162/evco.2006.14.3.345.
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Learning Classifier Systems (LCSs), such as the accuracy-based XCS, evolve distributed problem solutions represented by a population of rules. During evolution, features are specialized, propagated, and recombined to provide increasingly accurate subsolutions. Recently, it was shown that, as in conventional genetic algorithms (GAs), some problems require efficient processing of subsets of features to find problem solutions efficiently. In such problems, standard variation operators of genetic and evolutionary algorithms used in LCSs suffer from potential disruption of groups of interacting features, resulting in poor performance. This paper introduces efficient crossover operators to XCS by incorporating techniques derived from competent GAs: the extended compact GA (ECGA) and the Bayesian optimization algorithm (BOA). Instead of simple crossover operators such as uniform crossover or one-point crossover, ECGA or BOA-derived mechanisms are used to build a probabilistic model of the global population and to generate offspring classifiers locally using the model. Several offspring generation variations are introduced and evaluated. The results show that it is possible to achieve performance similar to runs with an informed crossover operator that is specifically designed to yield ideal problem-dependent exploration, exploiting provided problem structure information. Thus, we create the first competent LCSs, XCS/ECGA and XCS/BOA, that detect dependency structures online and propagate corresponding lower-level dependency structures effectively without any information about these structures given in advance.
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Gower, Artur L., I. David Abrahams, and William J. Parnell. "A proof that multiple waves propagate in ensemble-averaged particulate materials." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 475, no. 2229 (September 2019): 20190344. http://dx.doi.org/10.1098/rspa.2019.0344.
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Effective medium theory aims to describe a complex inhomogeneous material in terms of a few important macroscopic parameters. To characterize wave propagation through an inhomogeneous material, the most crucial parameter is the effective wavenumber . For this reason, there are many published studies on how to calculate a single effective wavenumber. Here, we present a proof that there does not exist a unique effective wavenumber; instead, there are an infinite number of such (complex) wavenumbers. We show that in most parameter regimes only a small number of these effective wavenumbers make a significant contribution to the wave field. However, to accurately calculate the reflection and transmission coefficients, a large number of the (highly attenuating) effective waves is required. For clarity, we present results for scalar (acoustic) waves for a two-dimensional material filled (over a half-space) with randomly distributed circular cylindrical inclusions. We calculate the effective medium by ensemble averaging over all possible inhomogeneities. The proof is based on the application of the Wiener–Hopf technique and makes no assumption on the wavelength, particle boundary conditions/size or volume fraction. This technique provides a simple formula for the reflection coefficient, which can be explicitly evaluated for monopole scatterers. We compare results with an alternative numerical matching method.
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Mazarei, Fatemeh, Gholamreza Honarasa, Hassan Pakarzadeh, and Iraj Sadegh Amiri. "Random distributed feedback fiber lasers: Impact of third-order dispersion." Journal of Nonlinear Optical Physics & Materials 28, no. 04 (December 2019): 1950035. http://dx.doi.org/10.1142/s0218863519500358.
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In this paper, one of the most modern random lasers known as random distributed feedback fiber laser is investigated when the third-order dispersion (TOD) is taken into account. The laser characteristics are simulated based on the nonlinear Schrödinger equations (NLSEs) where the power evolution of three interacting waves: the pump, the forward and the backward Stokes waves, are investigated as they propagate down the fiber. The results show that due to TOD, the output characteristics of the laser are changed and particularly, the output power becomes asymmetrical. Moreover, the impacts of fiber nonlinear coefficient and input power on the output power and the output spectrum are studied.
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Lellouch, Ariel, Mark A. Meadows, Tamas Nemeth, and Biondo Biondi. "Fracture properties estimation using distributed acoustic sensing recording of guided waves in unconventional reservoirs." GEOPHYSICS 85, no. 5 (September 1, 2020): M85—M95. http://dx.doi.org/10.1190/geo2019-0793.1.
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Perforation shots excite guided waves that propagate in a low-velocity unconventional shale reservoir. They have a frequency content of up to 700 Hz and are dispersive. We have analyzed horizontal crosswell perforation shots recorded by a distributed acoustic sensing (DAS) array. As guided waves propagate through a previously stimulated area, we observe a dramatic influence on the guided SH waves in the form of delayed arrival times, scattering, phase incoherency, and loss of amplitude and frequency. The leaky compressional waves undergo a gradual slowdown. Using a simple geometric analysis of the spatial locations of the distortions in the direct arrivals of the guided SH waves, we can estimate the half-lengths of the induced fractures, which range from 50% to 75% of the distance between the perforated and monitoring wells. Furthermore, we find that the propagation disturbances originate from the middle of the stimulated area. Other diffracted signals, notably from frac plugs, are clearly visible in the data. We report the first large-scale use of DAS records of guided waves. Their potential for high-resolution imaging and inversion of subsurface properties before and after hydraulic stimulation opens new possibilities for the use of seismology in optimizing production from unconventional reservoirs.
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Mitra, Anish, Abraham Z. Snyder, Tyler Blazey, and Marcus E. Raichle. "Lag threads organize the brain’s intrinsic activity." Proceedings of the National Academy of Sciences 112, no. 17 (March 30, 2015): E2235—E2244. http://dx.doi.org/10.1073/pnas.1503960112.
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It has been widely reported that intrinsic brain activity, in a variety of animals including humans, is spatiotemporally structured. Specifically, propagated slow activity has been repeatedly demonstrated in animals. In human resting-state fMRI, spontaneous activity has been understood predominantly in terms of zero-lag temporal synchrony within widely distributed functional systems (resting-state networks). Here, we use resting-state fMRI from 1,376 normal, young adults to demonstrate that multiple, highly reproducible, temporal sequences of propagated activity, which we term “lag threads,” are present in the brain. Moreover, this propagated activity is largely unidirectional within conventionally understood resting-state networks. Modeling experiments show that resting-state networks naturally emerge as a consequence of shared patterns of propagation. An implication of these results is that common physiologic mechanisms may underlie spontaneous activity as imaged with fMRI in humans and slowly propagated activity as studied in animals.
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Levin, Donald A. "Ancient Dispersals, Propagule Pressure, and Species Selection in Flowering Plants." Systematic Botany 31, no. 3 (July 1, 2006): 443–48. http://dx.doi.org/10.1600/036364406778388692.
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The importance of ancient long-distance migrations in shaping the geographical structure of genera and families is becoming ever more apparent. The long-distance immigrants were not random samples of their floras, but had attributes which made them prime candidates for the intercontinental sweepstakes. High propagule dispersability was one such trait. I propose that these invasive species also must have produced large numbers of propagules across their ranges, by virtue of large population numbers and sizes. They probably were widespread, major elements in their floras. These ideas are supported by the fact that propagule pressure is a prime determinant of a contemporary species' invasion potential, as is the size of its native geographical distribution. I propose that highly dispersable and propagule-rich lineages are likely to have high speciation rates, because access to new regions affords opportunities for ecological and geographical speciation. These lineages also may persist longer, being more broadly distributed in space. The evolutionary advantage of these lineages extends to periods of climatic change.
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Yu, Gui Bo, Feng He Tao, Shu Hai Wang, Li Jun Cao, and Qiao Ma. "Solidification Behavior of Lined Al2O3-ZrO2 Multiphase Ceramics in SHS Composite Pipes." Advanced Materials Research 905 (April 2014): 109–12. http://dx.doi.org/10.4028/www.scientific.net/amr.905.109.
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Hypoeutectic and hypereutectic Al2O3+ZrO2 multiphase ceramic-lined composite pipes were produced by using the gravitational separation self-propagate high-temperature (SHS) process. The microstructure of the ceramics was observed by means of SEM and EPMA. The multi-phase ceramics base consists of lamellar or rod-like eutecticum of ZrO2with Al2O3, and Al2O3dendrite is distributed between (Al2O3+ZrO2) eutecticum and the ZrO2is distributed on boundary area between (Al2O3+ZrO2) eutecticum in appearance of band and particle alone in the hypoeutectic multi-phase ceramics, and ZrO2is distributed between (Al2O3+ZrO2) eutecticum in appearance of snowflake-like or fishbone-like in hypereutectic multi-phase ceramics. On the basis of combustion synthesis, material thermodynamics, metallurgy dynamics and ceramics materials theory, the formation of microstructure mechanism have been systematically investigated.
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Behbahani-Nejad, M., and N. C. Perkins. "Harmonically Forced Wave Propagation in Elastic Cables With Small Curvature." Journal of Vibration and Acoustics 119, no. 3 (July 1, 1997): 390–97. http://dx.doi.org/10.1115/1.2889735.
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This study presents an investigation of coupled longitudinal-transverse waves that propagate along an elastic cable. The coupling considered derives from the equilibrium curvature (sag) of the cable. A mathematical model is presented that describes the three-dimensional nonlinear response of an extended elastic cable. An asymptotic form of this model is derived for the linear response of cables having small equilibrium curvature. Linear, in-plane response is described by coupled longitudinal-transverse partial differential equations of motion, which are comprehensively evaluated herein. The spectral relation governing propagating waves is derived using transform methods. In the spectral relation, three qualitatively distinct regimes exist that are separated by two cut-off frequencies which are strongly influenced by cable curvature. This relation is employed in deriving a Green’s function which is then used to construct solutions for in-plane response under arbitrarily distributed harmonic excitation. Analysis of forced response reveals the existence of two types of periodic waves which propagate through the cable, one characterizing extension-compressive deformations (rod-type) and the other characterizing transverse deformations (string-type). These waves may propagate or attenuate depending on wave frequency. The propagation and attenuation of both wave types are highlighted through solutions for an infinite cable subjected to a concentrated harmonic excitation source.
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Colleran, Brian P., and Katherine E. Goodall. "In Situ Growth and Rapid Response Management of Flood-Dispersed Japanese Knotweed (Fallopia japonica)." Invasive Plant Science and Management 7, no. 1 (March 2014): 84–92. http://dx.doi.org/10.1614/ipsm-d-13-00027.1.
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AbstractThe objective of this article is to identify growth patterns of Japanese knotweed propagules distributed by high-water events. Along four river systems, we collected and measured Japanese knotweed propagules that had been distributed by flooding approximately 1 yr earlier. Results indicate that the size of the emergent shoot may be determined by the extent of underground growth late in the growing season, although initially it is linked to the size of the propagule. Our results show that 70% of new plants originated from rhizome fragments, and 30% from stems. This proportion is similar to regeneration rates shown in laboratory studies. We suggest that the best way to prevent the spread of Japanese knotweed along rivers is to focus control efforts on those stands most susceptible to erosion and propagule dispersal. We also suggest that an early detection and rapid response management approach can be effectively utilized to eradicate these propagules, and effectively suppress the spread of Japanese knotweed. Our data-collection method also provides evidence that control of newly distributed propagules can be effectively accomplished without the use of herbicides or heavy mechanical tools.
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Baccus, Stephen A., Christie L. Sahley, and Kenneth J. Muller. "Multiple Sites of Action Potential Initiation Increase Neuronal Firing Rate." Journal of Neurophysiology 86, no. 3 (September 1, 2001): 1226–36. http://dx.doi.org/10.1152/jn.2001.86.3.1226.
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Sensory input to an individual interneuron or motoneuron typically evokes activity at a single site, the initial segment, so that firing rate reflects the balance of excitation and inhibition there. In a network of cells that are electrically coupled, a sensory input produced by appropriate, localized stimulation can cause impulses to be initiated in several places. An example in the leech is the chain of S cells, which are critical for sensitization of reflex responses to mechanosensory stimulation. S cells, one per segment, form an electrically coupled chain extending the entire length of the CNS. Each S cell receives input from mechanosensory neurons in that segment. Because impulses can arise in any S cell and can reliably propagate throughout the chain, all the S cells behave like a single neuron with multiple initiation sites. In the present experiments, well-defined stimuli applied to a small area of skin evoked mechanosensory action potentials that propagated centrally to several segments, producing S cell impulses in those segments. Following pressure to the skin, impulses arose first in the S cell of the same segment as the stimulus, followed by impulses in S cells in other segments. Often four or five separate initiation sites were observed. This timing of impulse initiation played an important role in increasing the frequency of firing. Impulses arising at different sites did not usually collide but added to the total firing rate of the chain. A computational model is presented to illustrate how mechanosensory neurons distribute the effects of a single sensory stimulus into spatially and temporally separated synaptic input. The model predicts that changes in impulse propagation in mechanosensory neurons can alter S cell frequency of firing by changing the number of initiation sites.
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Xie, Xi Shan, and Yan Ping Zeng. "The Effect of Inclusions on Mechanical Behaviour in Ultra-High Strength Alloy Steels." Materials Science Forum 654-656 (June 2010): 51–56. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.51.
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Inclusions are un-avoidable even in super-clean engineering alloy steels because of the necessary melting process. These inclusions (such as TiN, AlN etc) are considered as harmful phases especially for ultra-high strength alloy steels. The unique experiments (in-situ tension and in-situ fatigue tests) have been conducted in a loading chamber of scanning electron microscope. TiN often characterizes with large blocky cubic morphology. Cracks easily initiate at the sharp corners of TiN cubic particles or sometimes directly initiate in TiN particles because of its brittleness. These cracks propagate to the matrix and to introduce early failure. AlN small particles (in several microns) often distribute as inclusion chains in steels. At tensile and fatigue tests cracks very often initiate at the inclusion chains among AlN small particles and line up to develop voids, which rapidly propagate to the matrix till early failure. These important results reveal the harmful effect of inclusions in micro-scale and can be connected with tensile and fatigue loading processes for understanding the early failure mechanisms.
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Sun, Qiuli, and Kurt Gramoll. "Internet-based Distributed Collaborative Engineering Analysis." Concurrent Engineering 10, no. 4 (December 1, 2002): 341–48. http://dx.doi.org/10.1177/a030347.
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This paper proposes an engineering analysis environment that allows remote users to conduct three-dimensional finite element analysis collaboratively through the Internet. Java and Java 3D were chosen to develop the working prototype due to their advantages of platform-independence and network supporting. The environment allows remote users to work collaboratively on the same analysis object simultaneously. It reads the geometric data generated by the collaborative geometric modeling environment. The user can interact directly with the geometric model to perform operations, such as applying, editing, and deleting boundary conditions and forces. The operations are propagated among the team members, which creates a distributed shared environment. The commands are transmitted instead of the generated data, and thus the network traffic associated with the collaboration is minimized. Different from classical server/client models,# the environment adopts a strategy in which the client-side application has full analysis capabilities while the server only manages communication. The essential features for distributed collaboration are discussed. The actual design consideration of the working prototype is presented to help illustrate the complexity and development of the collaborative environment. The environment is open to the public at www.vcity.ou.edu.
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Mitra, Nilanjan, Alak K. Patra, Satya P. Singh, Shyamal Mondal, Prasanta K. Datta, and Shailendra K. Varshney. "Interfacial delamination in glass-fiber/polymer-foam-core sandwich composites using singlemode–multimode–singlemode optical fiber sensors: Identification based on experimental investigation." Journal of Sandwich Structures & Materials 22, no. 1 (September 29, 2017): 40–54. http://dx.doi.org/10.1177/1099636217733983.
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Identification of interfacial delamination in the glass fiber/polymer-foam-core sandwich composites is difficult if the delamination does not propagate to the side surface of the specimen. However, these damages may eventually lead to compromising the sandwich composite structural component. A cost-effective novel embedded fiber optic sensor is being proposed in this manuscript, which works on the principle of multimode interference, to perform distributed sensing of interfacial delamination within the sandwich composites while in service. Even though this easy to use methodology has been used to identify interfacial delamination, this methodology can also be used for different other types of interfacial/interlaminar distributed strain sensing of samples under mechanical as well as thermal loads.
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Masaki, Y., N. Hanasaki, K. Takahashi, and Y. Hijioka. "Propagation of biases in humidity in the estimation of global irrigation water." Earth System Dynamics 6, no. 2 (July 20, 2015): 461–84. http://dx.doi.org/10.5194/esd-6-461-2015.
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Abstract. Future projections on irrigation water under a changing climate are highly dependent on meteorological data derived from general circulation models (GCMs). Since climate projections include biases, bias correction is widely used to adjust meteorological elements, such as the atmospheric temperature and precipitation, but less attention has been paid to biases in humidity. Hence, in many cases, uncorrected humidity data have been directly used to analyze the impact of future climate change. In this study, we examined how the biases remaining in the humidity data of five GCMs propagate into the estimation of irrigation water demand and consumption from rivers using the global hydrological model (GHM) H08. First, to determine the effects of humidity bias across GCMs, we ran H08 with GCM-based meteorological forcing data sets distributed by the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP). A state-of-the-art bias correction method was applied to the data sets without correcting biases in humidity. Differences in the monthly relative humidity amounted to 11.7 to 20.4 % RH (percentage relative humidity) across the GCMs and propagated into differences in the estimated irrigation water demand, resulting in a range between 1152.6 and 1435.5 km3 yr−1 for 1971–2000. Differences in humidity also propagated into future projections. Second, sensitivity analysis with hypothetical humidity biases of ±5 % RH added homogeneously worldwide revealed the large negative sensitivity of irrigation water abstraction in India and East China, which are heavily irrigated. Third, we performed another set of simulations with bias-corrected humidity data to examine whether bias correction of the humidity can reduce uncertainties in irrigation water across the GCMs. The results showed that bias correction, even with a primitive methodology that only adjusts the monthly climatological relative humidity, helped reduce uncertainties across the GCMs: by using bias-corrected humidity data, the uncertainty ranges of irrigation water demand across the five GCMs were successfully reduced from 282.9 to 167.0 km3 yr−1 for the present period, and from 381.1 to 214.8 km3 yr−1 for the future period (RCP8.5, 2070–2099). Although different GHMs have different sensitivities to atmospheric humidity because different types of potential evapotranspiration formulae are implemented in them, bias correction of the humidity should be applied to forcing data, particularly for the evaluation of evapotranspiration and irrigation water.
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Getan, A., S. Molchanov, and B. Vainberg. "Intermittency for branching walks with heavy tails." Stochastics and Dynamics 17, no. 06 (August 13, 2017): 1750044. http://dx.doi.org/10.1142/s0219493717500447.
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Branching random walks on multidimensional lattice with heavy tails and a constant branching rate are considered. It is shown that under these conditions (heavy tails and constant rate), the front propagates exponentially fast, but the particles inside of the front are distributed very non-uniformly. The particles exhibit intermittent behavior in a large part of the region behind the front (i.e. the particles are concentrated only in very sparse spots there). The zone of non-intermittency (were particles are distributed relatively uniformly) extends with a power rate. This rate is found.
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Snow, B., and A. Hillier. "Mode conversion of two-fluid shocks in a partially-ionised, isothermal, stratified atmosphere." Astronomy & Astrophysics 637 (May 2020): A97. http://dx.doi.org/10.1051/0004-6361/202037848.
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Context. The plasma of the lower solar atmosphere consists of mostly neutral particles, whereas the upper solar atmosphere is mostly made up of ionised particles and electrons. A shock that propagates upwards in the solar atmosphere therefore undergoes a transition where the dominant fluid is either neutral or ionised. An upwards propagating shock also passes a point where the sound and Alfvén speed are equal. At this point the energy of the acoustic shock can separated into fast and slow components. The way the energy is distributed between the two modes depends on the angle of magnetic field. Aims. We aim to investigate the separation of neutral and ionised species in a gravitationally stratified atmosphere. The role of two-fluid effects on the structure of the shocks post-mode-conversion and the frictional heating is quantified for different levels of collisional coupling. Methods. Two-fluid numerical simulations were performed using the (PIP) code of a wave steepening into a shock in an isothermal, partially-ionised atmosphere. The collisional coefficient was varied to investigate the regimes where the plasma and neutral species are weakly, strongly, and finitely coupled. Results. The propagation speeds of the compressional waves hosted by neutral and ionised species vary and, therefore, velocity drift between the two species is produced as the plasma attempts to propagate faster than the neutrals. This is most extreme for a fast-mode shock. We find that the collisional coefficient drastically impacts the features present in the system, specifically the mode conversion height, type of shocks present, and the finite shock widths created by the two-fluid effects. In the finitely-coupled regime, fast-mode shock widths can exceed the pressure scale height, which may lead to a new potential observable of two-fluid effects in the lower solar atmosphere.
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Gelenbe, Erol, and Stelios Timotheou. "Random Neural Networks with Synchronized Interactions." Neural Computation 20, no. 9 (September 2008): 2308–24. http://dx.doi.org/10.1162/neco.2008.04-07-509.
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Large-scale distributed systems, such as natural neuronal and artificial systems, have many local interconnections, but they often also have the ability to propagate information very fast over relatively large distances. Mechanisms that enable such behavior include very long physical signaling paths and possibly saccades of synchronous behavior that may propagate across a network. This letter studies the modeling of such behaviors in neuronal networks and develops a related learning algorithm. This is done in the context of the random neural network (RNN), a probabilistic model with a well-developed mathematical theory, which was inspired by the apparently stochastic spiking behavior of certain natural neuronal systems. Thus, we develop an extension of the RNN to the case when synchronous interactions can occur, leading to synchronous firing by large ensembles of cells. We also present an O(N3) gradient descent learning algorithm for an N-cell recurrent network having both conventional excitatory-inhibitory interactions and synchronous interactions. Finally, the model and its learning algorithm are applied to a resource allocation problem that is NP-hard and requires fast approximate decisions.
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Tian, S. G., G. L. Xie, J. Xie, and X. M. Zhou. "Influence of Long-term Aging on Microstructure and Creep Behaviors of FGH95 Nickel-based Superalloy." High Temperature Materials and Processes 31, no. 6 (December 14, 2012): 755–58. http://dx.doi.org/10.1515/htmp-2012-0012.
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AbstractBy means of long-term aging treatment, creep properties measurement and microstructure observation, the influences of long-term aging on the microstructure and creep behaviors of FGH95 Superalloy are investigated. Results show that the fine γ′ particles dispersedly precipitate in the alloy after fully heat treated, and coarser γ′ phase discontinuously distribute along the grain boundaries. After the alloy is long-term aged at 723 K for 500 h, the fine γ′ phase with better cube degree and carbide particles distribute dispersedly in the alloy to enhance the creep resistance of the alloy for possessing a longer creep lifetime at the condition of 923 K and 1034 MPa. The deformed feature of the alloy is that configurations of slipping dislocations and the stacking fault appear in the alloy. As the creep goes on, the cracks initiate and propagate along the boundaries due to dislocations tangling in the grain boundaries for bringing out the stress concentration.
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Li, Zhenhua, Xinyu Wang, Tao Chen, Fan Feng, Pan Liu, and Yonghao Lu. "Experimental and Numerical Evaluation on Deformation and Fracture Mechanism of Cast Duplex Stainless Steel Tubular Specimen." Materials 13, no. 15 (August 4, 2020): 3430. http://dx.doi.org/10.3390/ma13153430.
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The deformation behavior and fracture mechanism of cast duplex stainless steel tubular specimens under different tensile stages were investigated through experimental and numerical evaluation. The results showed that the axial stress was redistributed due to the necking of the tubular specimen, the axial stress near the internal wall was larger than those near the external wall, and its maximum axial stress was distributed between the internal wall and the center of the wall thickness. Microcracks and voids were initiated under the maximum shear stress along the δ/γ phase interface and propagated to the ferrite interior. The voids were connected and merged into the main crack through the propagation of the microcracks. Moreover, the main crack first propagated to the internal wall and then rapidly propagated to the external wall. The fracture morphology can be divided into three types: shear lip zones that can be found on both the internal and external walls, and shear lip zones that can be found on either only the internal wall or the external wall.
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Alves, Carolina, Cristina Branco, and Celso Cunha. "Hepatitis Delta Virus: A Peculiar Virus." Advances in Virology 2013 (2013): 1–11. http://dx.doi.org/10.1155/2013/560105.
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The hepatitis delta virus (HDV) is distributed worldwide and related to the most severe form of viral hepatitis. HDV is a satellite RNA virus dependent on hepatitis B surface antigens to assemble its envelope and thus form new virions and propagate infection. HDV has a small 1.7 Kb genome making it the smallest known human virus. This deceivingly simple virus has unique biological features and many aspects of its life cycle remain elusive. The present review endeavors to gather the available information on HDV epidemiology and clinical features as well as HDV biology.
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Vining, William F., Fernando Esponda, Melanie E. Moses, and Stephanie Forrest. "How does mobility help distributed systems compute?" Philosophical Transactions of the Royal Society B: Biological Sciences 374, no. 1774 (April 22, 2019): 20180375. http://dx.doi.org/10.1098/rstb.2018.0375.
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Brains are composed of connected neurons that compute by transmitting signals. The neurons are generally fixed in space, but the communication patterns that enable information processing change rapidly. By contrast, other biological systems, such as ant colonies, bacterial colonies, slime moulds and immune systems, process information using agents that communicate locally while moving through physical space. We refer to systems in which agents are strongly connected and immobile as solid , and to systems in which agents are not hardwired to each other and can move freely as liquid . We ask how collective computation depends on agent movement. A liquid cellular automaton (LCA) demonstrates the effect of movement and communication locality on consensus problems. A simple mathematical model predicts how these properties of the LCA affect how quickly information propagates through the system. While solid brains allow complex network structures to move information over long distances, mobility provides an alternative way for agents to transport information when long-range connectivity is expensive or infeasible. Our results show how simple mobile agents solve global information processing tasks more effectively than similar systems that are stationary. This article is part of the theme issue ‘Liquid brains, solid brains: How distributed cognitive architectures process information’.
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Herman, David. "Genette meets Vygotsky: narrative embedding and distributed intelligence." Language and Literature: International Journal of Stylistics 15, no. 4 (November 2006): 357–80. http://dx.doi.org/10.1177/0963947006068654.
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Framed tales, or stories within stories, have garnered considerable attention from theorists of narrative in recent years. By and large, however, story analysts have not sought to account for why the practice of narrative embedding has persisted so long - or why it is so widespread - in the world’s folk traditions and written literatures. Using William Wordsworth’s The Ruined Cottage as its tutor-text, this article advances a broadly cognitive explanation for the pervasiveness and persistence of narrative embedding across so many different storytelling situations. My central claim is that, in conjunction with the cognitive activities of their interpreters, framed narratives such as The Ruined Cottage constitute intelligent systems - systems that both stage and facilitate the process of shared thinking about past events and about one’s own and other minds. Such systems propagate experiential frames - specifically, the experiences of character-narrators - across time and space. By contrast, in a story that does not involve narrative embedding, there will be a net decrease in the capacity of the system to communicate representations originating from sources potentially quite widely separated in space and time. Narrative embedding thus increases the distributional reach of a framed tale, enhancing the overall power of the knowledge-generating system to which it lends structure. Adapting Barbara Rogoff’s (1990) definition of intelligence as the socially supported ability to solve problems grounded in particular domains of activity, I explore how framed narratives can help distribute intelligence both synchronically (across regions of space and participants and material artifacts within those regions) and diachronically (across different temporal phases of a given spatial region).
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Oppenheimer, Hank. "A new species of Cyanea Gaud. (Lobelioideae, Campanulaceae) from Maui, Hawai`i." PhytoKeys 167 (November 20, 2020): 1–11. http://dx.doi.org/10.3897/phytokeys.167.55107.
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Cyanea heluensis H. Oppenheimer, sp. nov., a new, narrowly distributed endemic species, is herein described and illustrated with line drawings and digital field photos. It is currently known from a single mature plant and is restricted to the upper Helu planeze on leeward Mauna Kahalawai, West Maui, Hawaiian Islands. It differs from all other species of Cyanea Gaudich. with its narrow, shallowly lobed leaves, gently curved muricate corollas, and undulate sepals caducous in fruit. A key to the new species and its congeners on Mauna Kahalawai is provided. Its conservation status and efforts to propagate the species are discussed.
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Grauke, L. J., T. E. Thompson, Philip Forsline, and Kim Hummer. "Use of Core Subsets in Developing Germplasm Collections of Clonally Propagated Crops." HortScience 30, no. 4 (July 1995): 907D—907. http://dx.doi.org/10.21273/hortsci.30.4.907d.
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Core subsets have been formed in several clonally propagated crops; for pear (Pyrus), strawberry (Fragaria), mint (Mentha), currant (Ribes), blackberry (Rubus), blueberry (Vaccinium), apple (Malus), and pecan [Carya illinoinensis (Wangenh.) K. Koch]. Criteria for selecting entries into each core varies, as does the use each core receives. Core subsets have been selected for each of the major collections maintained at NCGR-Corvallis (pear, strawberry, mint, currant, blackberry, and blueberry). In general, core subsets include 10% of the full collection. Entries were selected on the basis of horticultural characteristics and species representation. Management of the collection is facilitated by recognition of core entries, which are frequently distributed. The 2500 accessions of the Malus collection are represented in a core subset of 200 accessions. Of those, 100 represent the 35 known species, while 100 accessions were selected from elite clones on the basis of horticultural characteristics. The core has been successfully used to find a superior virus indicator. Entries have been propagated in test orchards in five states. The core strategy was used to compare the pecan cultivar collection to seedlings from native populations throughout the species range. The analysis revealed gaps in the ex situ collection, and may have implications for in situ conservation. A core subset (26 cultivars) was selected by stratified sampling within the geographic regions to mirror the allele frequency of the cultivar collection, consciously including extreme expressions of each horticultural trait evaluated. The availability of the diverse subset has effected management and distribution.
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Postman, Joseph, Kim Hummer, Ed Stover, Robert Krueger, Phillip Forsline, L. J. Grauke, Francis Zee, Tomas Ayala-Silva, and Brian Irish. "Fruit and Nut Genebanks in the U.S. National Plant Germplasm System." HortScience 41, no. 5 (August 2006): 1188–94. http://dx.doi.org/10.21273/hortsci.41.5.1188.
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The year 2005 marked the 25th anniversary of the establishment of the U.S. Department of Agriculture (USDA) National Plant Germplasm System (NPGS), repositories devoted to clonally propagated, horticultural fruit and nut crops. During this quarter century, facilities in Hilo, Hawaii; Mayaguez, PR.; Miami, Fla.; and Riverside, Calif. were developed to preserve collections of tropical and subtropical fruit and nut crops; facilities in Brownwood, Texas; Corvallis, Ore.; Davis, Calif. and Geneva, N.Y. preserve the temperate crops. Each of these facilities now has internationally recognized, globally diverse collections of genetic resources for their assigned genera. Germplasm of unique genotypes are maintained as growing plants, evaluated for phenotypic and genotypic traits, documented in a national public germplasm database, and freely distributed as clonal propaggules to researchers and other germplasm users around the world. Seed collections represent wild populations for some crop relatives. These 8 genebanks maintain 30,000 accessions representing 1600 species of fruit and nut crops and their wild relatives. The genebanks distribute more than 15,000 accessions annually to international researchers. Although originally conceived as working collections for crop improvement, NPGS genebanks have also become invaluable in providing the raw materials for basic plant genetic research, reservoirs for rare or endangered species or vulnerable landraces, archives of historic cultivars, and field classrooms for educating the public. These collections preserve botanical treasures as well as the American horticultural heritage for now and for future generations.
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Sun, Linlin, Liu Chu, Jiajia Shi, and Eduardo Souza de Cursi. "The Impacts of Random Distributed Vacancy Defects in Steady-State Thermal Conduction of Graphene." Applied Sciences 9, no. 11 (June 10, 2019): 2363. http://dx.doi.org/10.3390/app9112363.
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The unavoidable vacancy defects dispersed throughout the entire pristine graphene tailor to the integrity of the lattice structure and thereby have complicated impacts on the mechanical and thermal properties of graphene. In order to analyze the influence of vacancy defects on the extraordinary thermal conductivity of graphene, three typical kinds of vacancy defects—namely center concentrated, periodic, and random distributed vacancy defects—are compared and discussed. In the steady-state thermal conduction, the finite element method (FEM) is performed to calculate the total thermal energy and temperature field. The equivalent coefficient of thermal conductivity is derived from thermal energy, amount of vacancy defects, and boundary condition. The chirality in graphene is discussed by the location of its heat source. Moreover, the Monte Carlo simulation is applied to propagate the uncertainty of random vacancy defects in the finite element model of pristine graphene. In this paper, we provide the robustness to defend the impacts of vacancy defects on thermal conduction and the fluctuation and divergence caused by a certain number of random vacancy defects.
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Chen, Wei R., Gongyu Y. Shen, Gordon M. Shepherd, Michael L. Hines, and Jens Midtgaard. "Multiple Modes of Action Potential Initiation and Propagation in Mitral Cell Primary Dendrite." Journal of Neurophysiology 88, no. 5 (November 1, 2002): 2755–64. http://dx.doi.org/10.1152/jn.00057.2002.
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The mitral cell primary dendrite plays an important role in transmitting distal olfactory nerve input from olfactory glomerulus to the soma-axon initial segment. To understand how dendritic active properties are involved in this transmission, we have combined dual soma and dendritic patch recordings with computational modeling to analyze action-potential initiation and propagation in the primary dendrite. In response to depolarizing current injection or distal olfactory nerve input, fast Na+ action potentials were recorded along the entire length of the primary dendritic trunk. With weak-to-moderate olfactory nerve input, an action potential was initiated near the soma and then back-propagated into the primary dendrite. As olfactory nerve input increased, the initiation site suddenly shifted to the distal primary dendrite. Multi-compartmental modeling indicated that this abrupt shift of the spike-initiation site reflected an independent thresholding mechanism in the distal dendrite. When strong olfactory nerve excitation was paired with strong inhibition to the mitral cell basal secondary dendrites, a small fast prepotential was recorded at the soma, which indicated that an action potential was initiated in the distal primary dendrite but failed to propagate to the soma. As the inhibition became weaker, a “double-spike” was often observed at the dendritic recording site, corresponding to a single action potential at the soma. Simulation demonstrated that, in the course of forward propagation of the first dendritic spike, the action potential suddenly jumps from the middle of the dendrite to the axonal spike-initiation site, leaving the proximal part of primary dendrite unexcited by this initial dendritic spike. As Na+conductances in the proximal dendrite are not activated, they become available to support the back-propagation of the evoked somatic action potential to produce the second dendritic spike. In summary, the balance of spatially distributed excitatory and inhibitory inputs can dynamically switch the mitral cell firing among four different modes: axo-somatic initiation with back-propagation, dendritic initiation either with no forward propagation, forward propagation alone, or forward propagation followed by back-propagation.
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Chen, Jing, and Zhoudao Lu. "Crack Extension Resistance of Normal-Strength Concrete Subjected to Elevated Temperatures." Advances in Materials Science and Engineering 2014 (2014): 1–12. http://dx.doi.org/10.1155/2014/683756.
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Determination of the residual crack extension resistance curves (KR-curves) associated with cohesive force distribution on fictitious crack zone of complete fracture process is implemented in present research. The cohesive force distributes according to bilinear softening traction-separation law proposed by Petersson. Totally ten temperatures varying from 20°C to 600°C and the specimen size of230×200×200 mm with initial-notch depth ratios 0.4 are considered. The load-crack mouth opening displacement curves (P-CMOD) of postfire specimens are obtained by wedge-splitting method from which the stress intensity factor curves (K-curves) are calculated. In each temperature, with the distribution of cohesive force along the fracture process zone, the residual fracture toughnessKR(Δa) increases with increasing crack lengthΔa, whereas theKR-curves decrease with increasing temperaturesTmfor the thermal damage induced. The stability analysis on crack propagation demonstrates that when the residualKR-curve is higher thanK-curve, the crack propagates steadily; otherwise, the crack propagates unsteadily.
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PERROTTA, ANDREA. "CONFIDENCE LIMITS WITH MULTIPLE CHANNELS AND ARBITRARY PROBABILITY DISTRIBUTIONS FOR SENSITIVITY AND EXPECTED BACKGROUND." International Journal of Modern Physics C 13, no. 08 (October 2002): 989–1001. http://dx.doi.org/10.1142/s0129183102003784.
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A MC method is proposed to compute upper limits, in a pure Bayesian approach, when the errors associated to the experimental sensitivity and to the expected background content are not Gaussian distributed or not small enough to apply the usual approximations. It is relatively easy to extend the procedure to the multichannel case (for instance when different decay branchings, or luminosities or experiments have to be combined). Some of the searches for supersymmetric particles performed in the DELPHI experiment at the LEP electron–positron collider use such a procedure to propagate the systematics into the calculation of the cross-section upper limits. One of these searches will be described as an example.
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Zeng, Yan Ping, Chun Mei Xu, Jian Xin Dong, Mai Cang Zhang, and Xi Shan Xie. "Micro Behavior Study of Non-Metallic Inclusion in High Strength Shaft Steel." Key Engineering Materials 297-300 (November 2005): 1229–34. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.1229.
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The composition, shape, size and distribution of non-metallic inclusions in a kind of high strength shaft steel enriched CoNi have been investigated. In situ tensile tests in special designed SEM have been conducted to trace the whole process of crack initiation and propagation till to fracture at inclusion. The experimental results show that the non-metallic inclusions in the high strength shaft steel are primarily AlN. Their average size is about 3.6µm. Sometimes, a string of inclusions distributes along the rolling direction. Non-metallic inclusion can induce crack to be initiated by inclusion debonding. When the inclusion size is larger than the critical size, the crack can propagate as the main crack that induces the specimen to fracture.
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Stjernholm, Simon. "DIY Preaching and Muslim Religious Authority." Journal of Muslims in Europe 8, no. 2 (May 20, 2019): 197–215. http://dx.doi.org/10.1163/22117954-12341393.
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Abstract This article investigates how a particular type of Muslim preacher, here conceptualised as a ‘do-it-yourself (DIY) preacher’, can propagate for and elaborate on Islamic teachings outside of and supplementary to mosques. A variety of physical and media spaces are used to reach audiences, especially youth, with religious messages. The article uses an analytical lens of DIY media, generational differences, religious authority and organic intellectuals to argue that such initiatives are important not only as counter-cultural expressions in relation to the majority society, but also in negotiations and authority struggles within diverse Muslim populations. The specific case used in the analysis is that of a Swedish Muslim preacher’s publicly distributed oratory.
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Tainaka, K., S. Fukazawa, H. Nishimori, M. Yokosawa, and S. Mineshige. "Spatial Pattern Formation of Interstellar Medium." International Astronomical Union Colloquium 134 (1993): 117–20. http://dx.doi.org/10.1017/s0252921100014007.
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AbstractPopulation dynamics of multi-phased interstellar medium (ISM) is investigated by using the lattice model in position-fixed reaction. Interactions between three distinct phases of gas, cold clouds, warm gas, and hot gas give rise to cyclic phase changes in ISM. Such local phase changes are propagated in space, and stochastic steady-state spatial pattern is finally achieved. We obtain the following two characteristic patterns: (1)When the sweeping rate of a warm gas into a cold component is relatively high, cold clouds associated with warm gas form small-scale clumps and are dispersively distributed, whereas hot gas covers large fraction of space.(2)When the sweeping rate is relatively low, in contrast, warm gas and cold clouds are diffusively and equally distributed, while hot gas component is substantially localized.
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Lellouch, Ariel, Steve Horne, Mark A. Meadows, Stuart Farris, Tamas Nemeth, and Biondo Biondi. "DAS observations and modeling of perforation-induced guided waves in a shale reservoir." Leading Edge 38, no. 11 (November 2019): 858–64. http://dx.doi.org/10.1190/tle38110858.1.
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Perforation shots can be recorded by downhole distributed acoustic sensing (DAS) arrays. In this study, we demonstrate that guided waves induced by perforation shots propagate in a low-velocity shale reservoir layer. Such guided waves have a high frequency content of up to 700 Hz and are dispersive, with lower frequencies propagating faster than higher frequencies. They can propagate as P- and S-waves, and their group velocity is higher than their phase velocity. The high temporal and spatial resolution of the DAS array enables unaliased recording despite short wavelengths. The guided waves disappear from the records when the well exits the shale formation. Synthetic modeling predicts their existence for acoustic and elastic cases in simple velocity models. We show that perforation shots from an offset well at a distance of about 270 m can be recorded by the DAS array. Induced guided S-waves undergo significant disturbances while propagating through previously stimulated zones. These disturbances manifest as kinematic and dynamic changes of the recorded wavefield and as scattered events. The nature of the stimulation-induced changes is interpreted as a combination of unknown spatial and temporal effects linked to fluid-filled fractures. Guided waves hold tremendous potential for high-resolution reservoir imaging and should be used in conjunction with conventional DAS arrays and state-of-the-art DAS interrogators.
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Knopoff, Damián A., and Facundo A. Trucco. "A compartmental model for antibiotic resistant bacterial infections over networks." International Journal of Biomathematics 13, no. 01 (December 12, 2019): 2050001. http://dx.doi.org/10.1142/s1793524520500011.
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This paper presents a compartmental model for bacterial infections in a population distributed over a network of individuals. Within each node, individuals interact, bacteria can be transmitted and the disease may be spread; moreover, the acquisition of bacterial antibiotic resistance is considered. In addition, nodes are connected through weighted edges, and consequently individuals from different nodes may interact. As a result, the infection may be propagated over the network. We perform an analysis on this propagation as well as numerical simulations in order to illustrate the validity of the model.
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Harrison, Robert, Daniel Vera, and Bilal Ahmad. "Towards the realization of dynamically adaptable manufacturing automation systems." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 379, no. 2207 (August 16, 2021): 20200365. http://dx.doi.org/10.1098/rsta.2020.0365.
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The transition from traditional to truly smart dynamically adaptable manufacturing demands the adoption of a high degree of autonomy within automation systems, with resultant changes in the role of the human, in both the manufacturing and logistics functions within the factory. In the context of smart manufacturing, this paper describes research towards the realization of adaptable autonomous automation systems from both the control and information perspectives. Key facets of the approach taken at WMG are described in relation to human–machine interaction, autonomous approaches to assembly and intra-logistics, integration and dynamic system-wide optimization. The progression from simple distributed behavioural components towards autonomous functional entities is described. Effective systems integration and the importance of interoperability in the realization of more distributed and autonomous automation systems are discussed, so that operational information can propagate seamlessly, eliminating the traditional boundary between operational technology and information technology systems, and as an enabler for global knowledge collection, analysis and optimization. This article is part of the theme issue ‘Towards symbiotic autonomous systems'.
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Barzun, Jacques. "Is Democratic Theory for Export?" Ethics & International Affairs 1 (March 1987): 53–71. http://dx.doi.org/10.1111/j.1747-7093.1987.tb00514.x.
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A prominent feature of American political consciousness is a desire to propagate democracy throughout the world. In our enthusiasm to share what we enjoy, Jacques Barzun sees that little attention is paid to exactly what we are trying to distribute. Through a brief historical survey of democracy, he shows that our popular conception of the term does not correspond with any particular definition. U.S. democracy has no central text and is distinctly different, in theory and in practice, from the democracy of other states, both historical and contemporary. Democracy is an abstract ideal that is a function of time. Its present incarnation in the United States emphasizes freedom and equality through the means and language of specific personal rights. Barzun sees an internal tension in this formulation, one that ultimately threatens both freedom and equality if exported to the rest of the world.
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WU, JIE, and FEI DAI. "QoS ROUTING IN HYPERCUBE MULTICOMPUTERS." Parallel Processing Letters 13, no. 01 (March 2003): 43–52. http://dx.doi.org/10.1142/s0129626403001136.
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In this paper, we present a coding method to capture QoS information in hypercube multicomputers. The coding method is based on a localized algorithm where each node interacts with its neighbors to gather QoS information. Specifically, each node maintains a QoS vector where the k-th element represents the guaranteed QoS performance to a destination that is k hops away. The localized algorithm exhibits desirable properties of self-stabilizing, self-optimizing, and self-healing. Simulation results show that this coding method provides a good approximation of the minimum QoS value to a k-hop destination and, at the same time, uses a relatively small number of packets to propagate a change in link state (QoS value) compared with the classical distributed Bellman-Ford method.
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Sarkar, J., J. Goswami, S. Chandra, and B. Ghosh. "Study of ion-acoustic solitary wave structures in multi-component plasma containing positive and negative ions and q-exponential distributed electron beam." Laser and Particle Beams 35, no. 4 (September 25, 2017): 641–47. http://dx.doi.org/10.1017/s0263034617000593.
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AbstractUsing reductive perturbation technique, small-amplitude ion-acoustic solitary wave has been investigated in multi-component dense plasma, in which an electron beam propagates along the general streaming motion. The electrons in plasma have the q-exponential distribution. The positive and negative ions follow a regular Maxwellian distribution. It has been found that the positive and negative ion densities as well as the beam concentration have significant effect on the formation and properties of solitary structures. The streaming velocities of corresponding particles also have pronounced effect on the features of the solitons.
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Petersen, Niklas, Alexandra Similea, Christoph Lange, and Steffen Lohmann. "TurtleEditor: A Web-Based RDF Editor to Support Distributed Ontology Development on Repository Hosting Platforms." International Journal of Semantic Computing 11, no. 03 (September 2017): 311–23. http://dx.doi.org/10.1142/s1793351x17400128.
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Ontologies are increasingly being developed on web-based repository hosting platforms such as GitHub. Accordingly, there is a demand for ontology editors which can be easily connected to the hosted repositories. TurtleEditor is a web-based RDF editor that provides this capability and supports the distributed development of ontologies on repository hosting platforms. It offers features such as syntax checking, syntax highlighting, and auto completion, along with a SPARQL endpoint to query the ontology. Furthermore, TurtleEditor integrates a visual editing view that allows for the graphical manipulation of the RDF graph and includes some basic clustering functionality. The text and graph views are constantly synchronized so that all changes to the ontology are immediately propagated and the views are updated accordingly. The results of a user study and performance tests show that TurtleEditor can indeed be effectively used to support the distributed development of ontologies on repository hosting platforms.
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Fuller, Kate Binzen, Christopher McIntosh, and Nina Zidack. "Valuing Disease Prevention in a Vegetatively Propagated Annual Crop: Benefits From the Montana Seed Potato Certification Program." Plant Disease 104, no. 8 (August 2020): 2060–67. http://dx.doi.org/10.1094/pdis-03-19-0443-sr.
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We examine the economic costs of potato virus Y (PVY) and benefits to commercial potato growers from using screened seed. To do so, we use a quantile regression model to explore disease spread. We use this model to predict disease prevalence and corresponding losses in commercial potato operations with and without a screening and certification program in place. Our analysis suggests that this screening is very important; the amount of PVY in seed in the summer test is the strongest predictor of PVY in the winter test of the variables in our model. The amount of PVY in the seed can have major effects on commercial potato grower revenues and profitability. Using data and models from Idaho, a major purchaser of Montana seed, we estimate the annual benefit from Montana’s program to Idaho to average $205 per acre or $22 million for the state. [Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .
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Ahmed, Shafique, Thomas Schumacher, Erik T. Thostenson, and Jennifer McConnell. "Performance Evaluation of a Carbon Nanotube Sensor for Fatigue Crack Monitoring of Metal Structures." Sensors 20, no. 16 (August 6, 2020): 4383. http://dx.doi.org/10.3390/s20164383.
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This article describes research that investigated the ability of a carbon nanotube (CNT) sensor to detect and monitor fatigue crack initiation and propagation in metal structures. The sensor consists of a nonwoven carrier fabric with a thin film of CNT that is bonded to the surface of a structure using an epoxy adhesive. The carrier fabric enables the sensor to be easily applied over large areas with complex geometries. Furthermore, the distributed nature of the sensor improves the probability of detecting crack initiation and enables monitoring of crack propagation over time. Piezoresistivity of the sensor enables strains to be monitored in real time and the sensor, which is designed to fragment as fatigue cracks propagate, directly measures crack growth through permanent changes in resistance. The following laboratory tests were conducted to evaluate the performance of the sensor: (1) continuous crack propagation monitoring, (2) potential false positive evaluation under near-threshold crack propagation conditions, and (3) crack re-initiation detection at a crack-stop hole, which is a commonly used technique to arrest fatigue cracks. Real-time sensor measurements and post-mortem fractography show that a distinguishable resistance change of the sensor occurs due to fatigue crack propagation that can be quantitatively related to crack length. The sensor does not show false positive responses when the crack does not propagate, which is a drawback of many other fatigue sensors. The sensor is also shown to be remarkably sensitive to detecting crack re-initiation.
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Sutoyo, Sutoyo, Sabrani Sabrani, and Fitri Hidayati. "Pemodelan Data Pengukuran Sinyal Satelit Kanal C-Band Wilayah Pekanbaru." Jurnal Sains dan Teknologi Industri 17, no. 1 (December 20, 2019): 11. http://dx.doi.org/10.24014/sitekin.v16i2.9540.
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Salah satu pemanfaatan komunikasi satelit adalah penggunaan teknologi VSAT pada televisi berbayar menggunakan frekuensi C-band (4 GHz - 6 GHz) dan Ku-band (11 GHz - 14 GHz). Penggunaan frekuensi ini tentunya sangat dipengaruhi oleh redaman hujan. Untuk itu diperlukan perancangan dan pengukuran untuk mendapatkan pengaruh redaman hujan terhadap propagasi sinyal satelit. Pada penelitian ini terbatas pada pengukuran sinyal satelit untuk kanal C-band pada Wilayah Pekanbaru. Hasil data pengukuran kemudian dilakukan pemodelan distribusi data untuk mengetahui karakteristik data penerimaan sinyal satelit untuk kanal C-band. Berdasarkan hasil pemodelan data pengukuran sinyal satelit diperoleh bahwa data pengukuran terdistribusi rician dengan MSE C-band = 0,056052057