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1
Werdina, Ghassan M., and Omar Q. Aziz. "Interaction between the Local and General Zone for the Post-tensioned Girder Anchorage Zone." Open Civil Engineering Journal 15, no. 1 (April 16, 2021): 50–73. http://dx.doi.org/10.2174/1874149502115010050.
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Background: The use of post-tensioning in girders causes high bearing and compressive stresses in the anchorage zone. In this study, the behavior of the anchorage zone and the interaction between the local and general zone are investigated. The variables included different reinforcements for both the local and general zones for a block of two anchorage devices. Methods: Both experimental and numerical methods have been applied to study the behavior of the anchorage zone. The experimental part of the study involved laboratory testing of sixteen specimens, and the numerical study was conducted using ABAQUS non-linear finite element analysis. Results: Tie reinforcement provided additional confinement for the local zone, and this confinement was more for the specimens with originally less confined spiral reinforcement strength. There was a slight or no effect of the local zone reinforcement on the general zone strength and ultimate load of the anchorage zone when the failure was in the general zone. Conclusion: Confinement of the local zone prevented the brittle bearing and compression failure of this zone.
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Slayzak, S. J., R. Viskanta, and F. P. Incropera. "Effects of Interactions Between Adjoining Rows of Circular, Free-Surface Jets on Local Heat Transfer From the Impingement Surface." Journal of Heat Transfer 116, no. 1 (February 1, 1994): 88–95. http://dx.doi.org/10.1115/1.2910888.
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Experiments have been conducted to obtain single-phase local heat transfer coefficient distributions associated with impingement of one or two rows of circular, free-surface water jets on a constant heat flux surface. The nozzle diameter, the centerline-to-centerline distance between nozzles in a row, and the nozzle-to-heater separation distance were fixed at 4.9, 6.3, and 89.7 mm, respectively. Two row-to-row separations (81 and 51 mm) were considered, and nozzle discharge Reynolds numbers were varied over the range from 16,800 to 30,400. The interaction zone created by opposing wall jets from adjacent rows is characterized by an upwelling of spent flow (an interaction fountain) for which local coefficients can approach those of the impingement zones. Interactions between wall jets associated with nozzles in one row can create sprays that impact the adjoining row with sufficient momentum to induce a dominant/subordinate row behavior. In this case the interaction zone is juxtaposed with the subordinate row, and local coefficients in the impingement and wall jet regions of the affected row may be significantly enhanced. This result contrasts with the deleterious effects of crossflow reported for submerged jets throughout the literature. Spray-induced enhancements, as well as interaction zone maxima, increase with decreasing row-to-row pitch and with increasing Reynolds number.
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Xie, C. Y. "Genotype by environment interaction and its implications for genetic improvement of interior spruce in British Columbia." Canadian Journal of Forest Research 33, no. 9 (September 1, 2003): 1635–43. http://dx.doi.org/10.1139/x03-082.
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Ten-year height data from 232 open-pollinated interior spruce families tested in five seed planning zones located in north-central interior British Columbia were used to investigate the extent and pattern of genotype by environment (G×E) interaction and to examine the validity of the seed planning zone delineation in this region. The G×E interaction in the entire region was both statistically and practically significant, with an estimated type b genetic correlation coefficient of 0.64. The detected geographic pattern of the G×E interaction indicates that the old delineation is overly conservative, and consolidating the five old zones into the two new zones is a valid decision. A procedure was developed to convert the expected genetic gain, with respect to the old zone, to the new zone when seed from a rogued local seed orchard is used for reforestation in the entire new zone. A similar procedure was also proposed to predict the breeding value of an individual that was only tested in the old zone of its origin with respect to the new zone. Given the detected amounts of the G×E interaction, and considering other factors, using three to five sites in each new zone for the second-generation progeny testing seems to be appropriate.
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Streeck, Jürgen, and Kathryn E. Harrison. "Children’s interaction in an urban face-to-face society." Pragmatics and Society 6, no. 3 (September 28, 2015): 305–37. http://dx.doi.org/10.1075/ps.6.3.01str.
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This paper reports on a micro-ethnography of social interaction in an urban plaza in Colombia, focusing on the plaza’s role as an arena for the acquisition of interaction skills. We investigate how children of different ages initiate and sustain interactions with same-age and older peers and the efforts they make to be recognized and ‘visible’. We interpret our data in light of three theories of socialization: Corsaro’s (1997) conception of childhood as “interpretive reproduction”, Vygotsky’s (1978) model of the “zone of proximal development”, and the “structural approach” to social cognition and development (Damon 1977; Younnis 1984). While a social form like the plaza, which is collectively enacted by members of all age groups of the local community, provides children with an extraordinarily rich array of opportunities to develop social communication skills by interacting with older and younger peers, our analysis also demonstrates that children, as they are building zones of proximal development for themselves, play a central role in assembling, integrating, and sustaining the neighborhood as a face-to-face society. In this fashion, the paper illustrates how the micro-analysis of social interaction can contribute to the analysis of social ‘macro’ forms.
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Samsonov, T. E., and K. S. Trigub. "Mapping of local climate zones of Moscow city." Geodesy and Cartography 936, no. 6 (July 20, 2018): 14–25. http://dx.doi.org/10.22389/0016-7126-2018-936-6-14-25.
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Local climatic zones are areas with a uniform land cover, structure, materials and a specific character of human activity, which have a special type of interaction with the surface layer of the atmosphere. Allocating climatic zones in cities provides possibility to reduce various combinations of built-up and land cover to a limited number of classes that can be used to unify the places of observing urban heat island, and to facilitate detailed climatic and meteorological modeling. The article presents the experience of mapping the local climatic zones of Moscow based on the Landsat 8 space imagery within the framework of the WUDAPT (World Urban Database Project) project. Evaluation of quality of space imagery interpretation was carried out by the method of cross-validation of the training samples. The analysis of the derived zones distribution is presented, estimation of their content is made on the basis of OpenStreetMap data, the availability of meteorological stations in different zone types is calculated, and prospects of further research are outlined.
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Saruwatari, Ayumi, Junichi Otsuka, and Yasunori Watanabe. "SEDIMENT ADVECTION AND DIFFUSION BY OBLIQUELY DESCENDING EDDIES." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 96. http://dx.doi.org/10.9753/icce.v36.sediment.96.
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Three-dimensional vortex structures involving obliquely descending eddies (ODE), produced by depth-induced breaking-waves, has been proved to be associated with local sediment suspension in the surf zone (Zhou et al., 2017); vertical velocity fluctuations around the ODEs induces sediment suspension near the bed. Otsuka et al. (2017) explained the mechanical contributions of the ODEs to enhance local sediment suspension under the breaking waves and modeled the vortex-induced suspension to predict the profile of the equilibrium sediment concentration in the surf zone. In order to predict local behaviors of sediment, however, sediment-turbulence interactions in the transitional turbulence under breaking waves need to be understood. The interaction may be described in terms of Schmidt number (Sc). Sc has been empirically determined for trivial steady flows such as open channel or pipe flows. In the surf zone where organized flows evolve into a turbulent bore, the interaction may vary with the transitional feature of turbulence during a wave-breaking process, and thus Sc may be variable in time and space. No appropriate Sc model has been proposed for the surf zone flow. A parametric study on the sediment motion with respect to the variation of Sc is required for better prediction of sediment transport in the surf zone. In this study, contributions of the sediment advection and diffusion in the vortex structure to the concentration are computationally investigated. Effects of Sc to the sediment suspension and diffusion process will be also discussed in this work.
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Malik, L., L. N. Pussegoda, B. A. Graville, and W. R. Tyson. "Crack Arrest Toughness of a Heat-Affected Zone Containing Local Brittle Zones." Journal of Offshore Mechanics and Arctic Engineering 118, no. 4 (November 1, 1996): 292–99. http://dx.doi.org/10.1115/1.2833918.
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The awareness of the presence of local brittle zones (LBZs) in the heat-affected zone (HAZ) of welds has led to the requirements for minimum initiation (CTOD) toughness for the HAZ for critical applications (API RP 2Z, CSA S473). Such an approach, however, is expensive to implement and limits the number of potential steel suppliers. A fracture control philosophy that is proposed to be an attractive alternative for heat-affected zones containing LBZs is the prevention of crack propagation rather than of crack initiation. Such an approach would be viable if it could be demonstrated that cracks initiated in the LBZs will be arrested without causing catastrophic failure, notwithstanding the low initiation (CTOD) toughness resulting from the presence of LBZs. Unstable propagation of a crack initiating from an LBZ requires the rupture of tougher microstructural regions surrounding the LBZ in HAZ, and therefore the CTOD value reflecting the presence of LBZ is unlikely to provide a true indication of the potential for fast fracture along the heat-affected zone. Base metal specifications (CSA S473) usually ensure that small unstable cracks propagating from the weld zone into the base metal would be arrested. Past work has also shown that unstable crack initiation resulting from interaction of surface semi-elliptical cracks parallel to the fusion boundary with the local brittle zones can get arrested once the crack has popped through the depth of the LBZ. However, the potential for arrest when a through-thickness HAZ crack runs parallel to the fusion boundary, and thus parallel to the LBZs, has not been examined previously. To investigate the likelihood of fast fracture within the HAZ, a test program has been carried out that involved performing compact plane strain (ASTM E1221) and plane stress crack arrest tests on a heataffected zone that contained LBZs, and thus exhibited unacceptable low CTOD toughness for resistance to brittle fracture initiation. The results indicated that in contrast to the initiation toughness (CTOD toughness), the crack arrest toughness was little influenced by the presence of local brittle zones. Instead, the superior toughness of the larger proportion of finer-grain HAZ surrounding the LBZ present along the crack path has a greater influence on the crack arrest toughness. It further seems that there may be potential to estimate the HAZ crack arrest toughness from more conventional smaller-scale laboratory tests, such as conventional or precracked instrumented Charpy impact tests.
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XU, CHANG-YUE, LI-WEI CHEN, and XI-YUN LU. "NUMERICAL SIMULATION OF SHOCK WAVE AND TURBULENCE INTERACTION OVER A CIRCULAR CYLINDER." Modern Physics Letters B 23, no. 03 (January 30, 2009): 233–36. http://dx.doi.org/10.1142/s0217984909018084.
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The interaction of shock wave and turbulence for transonic flow over a circular cylinder is investigated using detached-eddy simulation (DES). Several typical cases are calculated for free-stream Mach number M∞ from 0.85 to 0.95, and the physical mechanisms relevant to the shock wave and turbulence interaction are discussed. Results show that there exist two flow states. One is unsteady flow state with moving shock waves interacting with turbulent flow for M∞ < 0.9 approximately, and the other is quasi-steady flow with stationary shocks standing over the wake of the cylinder for M∞ > 0.9, suppressing the vortex shedding from the cylinder. Moreover, local supersonic zones are identified in the wake of the cylinder and generated by two processes, i.e., reverse flow and shock wave distortion induced the supersonic zone. Turbulent shear layer instabilities are revealed and associated with moving shock wave and traveling pressure wave.
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Pokhotelov, O. A., V. A. Pilipenko, and M. Parrot. "Strong atmospheric disturbances as a possible origin of inner zone particle diffusion." Annales Geophysicae 17, no. 4 (April 30, 1999): 526–32. http://dx.doi.org/10.1007/s00585-999-0526-2.
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Abstract. A new mechanism of the atmosphere-magnetosphere interaction, which might be called "acoustic-magnetospheric cyclotron accelerator", is proposed. The idea of this mechanism stems from the fact that strong acoustical perturbations in the ionosphere (e.g., due to earthquakes, thunderstorms, etc.) may generate magnetic disturbances in the magnetosphere. Then, the latter will induce local resonant acceleration and subsequent inward diffusion of trapped particles. This idea may be fruitful in the interpretation of some occasional increases in inner zone particle fluxes which do not correlate with the solar or magnetospheric activities.Key words. Ionosphere (active experiments; ionosphere-atmosphere interactions; particle acceleration)
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Schaefer, Florian, Matthias Thielen, Michael Marx, and Christian Motz. "How to Measure a Dislocation’s Breakthrough Stress to Estimate the Grain Boundary Resistance against Slip Transfer Based on the DFZ-Model of Fracture." Solid State Phenomena 258 (December 2016): 93–96. http://dx.doi.org/10.4028/www.scientific.net/ssp.258.93.
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Stage-I-fatigue-cracks are used as highly localized dislocation sources with well-known Burger’s vectors to study the interaction between dislocations and grain boundaries. This interaction in the plastic zone is of particular interest to understand the fluctuating crack growth in the very short crack regime. In the case of a blocked slip band the dislocations pile up at the grain boundary causing a local stress concentration. The resulting local stress distribution is calculated based on measurements of the dislocation density distribution in the plastic zone. For this purpose the slip line profiles were measured by AFM, the dislocation density distribution was determined and the dislocation-free zone model of fracture (DFZ) was validated. With this it is possible to quantify the grain boundary resistance and to combine geometric and stress approach for grain boundary resistance against slip transfer.
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Zuikov, Andrey L., and Elena V. Bazhina. "Viscous stress tensor and stability of laminar contravortical flows." Vestnik MGSU, no. 7 (July 2019): 870–84. http://dx.doi.org/10.22227/1997-0935.2019.7.870-884.
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Introduction: coaxial layers in contravortical flows rotate in the opposite directions. This determines their complicated spatial structure. The relevance of the subject is in the uniquely effective mixing of the moving medium. This property has a great potential of application from microbiology and missile building for obtaining highly dispersed mixtures to heat engineering for increasing the intensity of heat transfer. However, contravortical flows have a high degree of hydrodynamic instability. This hinders effective development of these technologies. Contravortical flows are observed behind Francis hydroturbines, whose derated operation causes modes with a significant increase of hydraulic unit vibrations up to destruction of the units. The purpose of the study is to identify physical laws of the contravortical flow hydrodynamics, common for both laminar and turbulent fluid flow modes.
Materials and methods: theoretical analysis of the viscous stress tensor and local stability zones of contravortical laminar flows.
Results: the article provides a mathematical description of the tensor of viscous tangential (τij) and normal (σii) stresses as well as local stability zones of the flow according to Rayleigh (Ra) and Richardson (Ri) criteria. The graphs of the radial-axial distributions of the viscous stress components are given, local stability zones are shown and the point of “vortex breakdown” is indicated. The solutions are obtained in the form of Fourier – Bessel series. The hydrodynamic structure of the flow is analysed.
Conclusions: it is established that the most significant viscous stresses are observed at the beginning of the interaction zone of contrarotating layers. It is established that the areas with the most unstable flow are localized in the flow vortex core. Three zones can be distinguished in the vortex core: a zone of weak instability with local Richardson numbers to Ri = –1, passing into a zone of flow destabilization with high negative values of Richardson numbers Ri = –10 to –100, in turn, transforming into a zone with rapidly increasing instability up to Ri = –1000. This is a zone of loss of flow stability, culminating in the “ortex breakdown”.
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Chen, Jianjun, Geng Lai, and Wancheng Sheng. "On the rarefaction waves of the two-dimensional compressible Euler equations for magnetohydrodynamics." Journal of Hyperbolic Differential Equations 17, no. 03 (September 2020): 591–612. http://dx.doi.org/10.1142/s0219891620500174.
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The expansion of a wedge of magnetic fluid into vacuum is studied in this paper. The magnetic fluid away from the sharp corner of a wedge expands into the vacuum as two plane-symmetric rarefaction waves, and the problem can be reduced to the interaction of these two rarefaction waves. In order to determine the flow in the interaction zone, we formulate a Goursat problem for the two-dimensional, self-similar Euler equations of magnetohydrodynamic. This system is of mixed type, and the type at each point is determined by the local fluid velocity and the local magneto-acoustic speed. We establish that the system is uniformly hyperbolic in the interaction zone when the half-angle of the wedge is less than some angle [Formula: see text], while the existence of a global classical solution to the Goursat problem is proven by a method of characteristic decomposition.
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PIROZZOLI, SERGIO, MATTEO BERNARDINI, and FRANCESCO GRASSO. "Direct numerical simulation of transonic shock/boundary layer interaction under conditions of incipient separation." Journal of Fluid Mechanics 657 (June 24, 2010): 361–93. http://dx.doi.org/10.1017/s0022112010001710.
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The interaction of a normal shock wave with a turbulent boundary layer developing over a flat plate at free-stream Mach number M∞ = 1.3 and Reynolds number Reθ ≈ 1200 (based on the momentum thickness of the upstream boundary layer) is analysed by means of direct numerical simulation of the compressible Navier–Stokes equations. The computational methodology is based on a hybrid linear/weighted essentially non-oscillatory conservative finite-difference approach, whereby the switch is controlled by the local regularity of the solution, so as to minimize numerical dissipation. As found in experiments, the mean flow pattern consists of an upstream fan of compression waves associated with the thickening of the boundary layer, and the supersonic region is terminated by a nearly normal shock, with substantial bending of the interacting shock. At the selected conditions the flow does not exhibit separation in the mean. However, the interaction region is characterized by ‘intermittent transitory detachment’ with scattered spots of instantaneous flow reversal throughout the interaction zone, and by the formation of a turbulent mixing layer, with associated unsteady release of vortical structures. As found in supersonic impinging shock interactions, we observe a different amplification of the longitudinal Reynolds stress component with respect to the others. Indeed, the effect of the adverse pressure gradient is to reduce the mean shear, with subsequent suppression of the near-wall streaks, and isotropization of turbulence. The recovery of the boundary layer past the interaction zone follows a quasi-equilibrium process, characterized by a self-similar distribution of the mean flow properties.
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Rostom, Gerard R. "THE APPLICABILITY OF THE SPECIAL ECONOMIC ZONE MODEL OF LOCAL DEVELOPMENT IN THE LIPETSK REGION." GEOGRAPHY, ENVIRONMENT, SUSTAINABILITY 11, no. 4 (January 4, 2019): 14–23. http://dx.doi.org/10.24057/2071-9388-2018-11-4-14-23.
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The model of regional economic development in the Lipetsk region based on the allocation of industry and agriculture production in Special Economic Zones has shown its effectiveness for the development of the whole region. However, this model was helpless to introduce any significant breakthrough changes in the structure of the economy. Currently there has been an attempt to apply the same allocation model to tourism segment objects. It is shown that tourist entities unlike industrial and agricultural have different development imperatives. The main condition for the successful formation and functioning of tourist objects on a territory is their interconnected interaction within a tourist cluster. A tourist cluster can not be created at the only site. Tourist objects of a tourist cluster must be distributed according to tourist destinations and integrated through a well-developed infrastructure in a single functional system. When applying the special economic zone model to a territory it is necessary to make adaptations in accordance to the specifics of the allocated objects. The conclusion is that the application of the same management model for different economy segments needs adjustment. It is also important to distinguish a “Cluster” which is a geographic concentration of interconnected companies and a “Special Economic Zone” which is a territory with economic preferences.
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Thapa, Kamal. "Park–People Interaction and Public Perceptions towards Parsa Wildlife Reserve, Nepal." Journal of Forest and Livelihood 14, no. 1 (August 31, 2016): 41–52. http://dx.doi.org/10.3126/jfl.v14i1.23161.
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Protected areas (PAs) are established to conserve biodiversity and ecosystems. PAs also provide natural resources to local people that support their livelihoods. However, local people residing nearby PAs often face diverse costs that may influence their overall attitude towards PAs. This actually determines the degree of participation and support of local people in nature conservation. This paper assesses the attitude of local people towards PAs taking a case of Parsa Wildlife Reserve (PWR). The research methods employed were household survey followed by focus group discussions, key informant’s interview and participant observation. This study found that the local people in and around the PWR have negative attitude towards it. Only 34 per cent liked its presence whereas 58 per cent of the respondents were not happy to be included in the buffer zone. Reasons for disliking the reserve was mainly due to wildlife damage; restrictions in resource use; and arrest and prosecution by the park authorities. In contrast, reasons for liking the reserve were the opportunities for natural resource use, biodiversity conservation, and tourism/business. The paper concludes that by addressing the negative attitudes of local people helps the reserve authority to enhance long term sustainability of PWR.
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Ó Dochartaigh, Brighid É., Alan M. MacDonald, Andrew R. Black, Jez Everest, Paul Wilson, W. George Darling, Lee Jones, and Mike Raines. "Groundwater–glacier meltwater interaction in proglacial aquifers." Hydrology and Earth System Sciences 23, no. 11 (November 5, 2019): 4527–39. http://dx.doi.org/10.5194/hess-23-4527-2019.
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Abstract. Groundwater plays a significant role in glacial hydrology and can buffer changes to the timing and magnitude of flows in meltwater rivers. However, proglacial aquifer characteristics or groundwater dynamics in glacial catchments are rarely studied directly. We provide direct evidence of proglacial groundwater storage, and quantify multi-year groundwater–meltwater dynamics, through detailed aquifer characterisation and intensive high-resolution monitoring of the proglacial system of a rapidly retreating glacier, Virkisjökull, in south-eastern Iceland. Proglacial unconsolidated glaciofluvial sediments comprise a highly permeable aquifer (25–40 m d−1) in which groundwater flow in the shallowest 20–40 m of the aquifer is equivalent to 4.5 % (2.6 %–5.8 %) of mean river flow, and 9.7 % (5.8 %–12.3 %) of winter flow. Estimated annual groundwater flow through the entire aquifer thickness is 10 % (4 %–22 %) the magnitude of annual river flow. Groundwater in the aquifer is actively recharged by glacier meltwater and local precipitation, both rainfall and snowmelt, and strongly influenced by individual precipitation events. Local precipitation represents the highest proportion of recharge across the aquifer. However, significant glacial meltwater influence on groundwater within the aquifer occurs in a 50–500 m river zone within which there are complex groundwater–river exchanges. Stable isotopes, groundwater dynamics and temperature data demonstrate active recharge from river losses, especially in the summer melt season, with more than 25 % and often >50 % of groundwater in the near-river aquifer zone sourced from glacier meltwater. Proglacial aquifers such as these are common globally, and future changes in glacier coverage and precipitation are likely to increase the significance of groundwater storage within them. The scale of proglacial groundwater flow and storage has important implications for measuring meltwater flux, for predicting future river flows, and for providing strategic water supplies in de-glaciating catchments.
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Khesin, Boris, Yevgeny Vapnik, and Sonya Itkis. "Geophysical evidence of deep hydrocarbon flow in Mottled Zone areas, Dead Sea Transform zone." GEOPHYSICS 75, no. 3 (May 2010): B91—B101. http://dx.doi.org/10.1190/1.3375236.
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The origin of unusual magnetic initially sedimentary rocks of the Mottled Zone (MZ) in Israel and Jordan remained enigmatic for several decades until integrated characterization of the MZ area was achieved by ground magnetic measurements and geologic observations along representative profiles in parallel with reprocessing and reinterpretation of available aeromagnetic and gravity data. Micromagnetic profiling was combined with gamma-radioactivity measurements, and representative samples were selected to determine rock physical properties. Results of field measurements, reduction and transformation of geophysical fields, anomaly inversion, and forward modeling accompanied by geologic analysis suggest that two types of magnetic anomalies and local gravity minima in the MZ areas are related to the same event, i.e., deep hydrocarbon flow associated with fossil mud volcanism. Physicochemical interaction of deep hydrocarbon flow and surrounding sedimentary rocks caused widespread weak magnetization and corresponding aeromagnetic anomalies. Other scattered heterogeneous magnetization and linked ground magnetic anomalies are common for surface/near-surface local sources and are caused by the burning of combustible gases ejected by mud volcanoes; such origin of the magnetization is confirmed by magnetic measurements of burned rocks in mud volcano areas of the Caucasus. Increased radioactivity of the lower part of the MZ likely indicates mud ejection from a deep uranium-enriched source. Locations of MZ outcrops commonly coincide with residual gravity minima, showing zones of disintegration and possible hydrocarbon accumulations. Seismic prospecting data support the existence of disintegration zones at depth. Results show the need for additional geophysical studies and a potential for revealing hydrocarbon accumulations in the MZ areas, particularly at the Halamish, Nevatim, Ma’ale Adumim, and Nabi Musa sites.
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Chen, Bin, Peidong Wu, and Huajian Gao. "Geometry- and velocity-constrained cohesive zones and mixed-mode fracture/adhesion energy of interfaces with periodic cohesive interactions." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 465, no. 2104 (December 9, 2008): 1043–53. http://dx.doi.org/10.1098/rspa.2008.0373.
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We show that the mixed-mode fracture/adhesion energy of an interface with periodically varying cohesive interactions generally depends on the size of the cohesive zone near the tip of a crack along the interface: it is equal to the average cohesive energy of the interface, if the cohesive zone size is much larger than the period of cohesive interaction but becomes the peak value of the local cohesive energy when the opposite is true. It is also interesting that the cohesive zone size can be strongly influenced by the geometry and velocity of the crack. As an example of geometry-constrained cohesive zone, we consider peeling of a thin film on substrate and show that the cohesive zone size under 90° peeling scales with the bending stiffness of the film, while that under 0° peeling scales with the tension stiffness of the film. As an example of a velocity-constrained cohesive zone, we consider crack propagation along an interfacial layer of weak molecular bonds joining two elastic media and show that the cohesive zone size can be altered by an order of magnitude over feasible regimes of crack velocity. These results suggest possible strategies to control fracture/adhesion strength of interfaces in both engineering and biological systems.
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Bo, Tang, Gao Gangfeng, Xia Xiangwu, and Yang Xiu. "Integrated Energy System Configuration Optimization for Multi-Zone Heat-Supply Network Interaction." Energies 11, no. 11 (November 6, 2018): 3052. http://dx.doi.org/10.3390/en11113052.
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The integrated energy system effectively improves the comprehensive utilization of energy through cascade utilization and coordinated scheduling of various types of energy. Based on the independent integrated energy system, the thermal network interaction between different load characteristic regions is introduced, requiring a minimum thermal grid construction cost, CCHP investment operation cost and carbon emission tax as the comprehensive optimization targets, and making overall optimization to the configuration and operation of the multi-region integrated energy systems. This paper focuses on the planning of equipment capacity of multi-region integrated energy system based on a CCHP system and heat network. Combined with the above comprehensive target and heat network model, a mixed integer linear programming model for a multi-region CCHP system capacity collaborative optimization configuration is established. The integrated energy system, just a numerical model solved with the LINGO software, is presented. Taking a typical urban area in Shanghai as an example, the simulation results show that the integrated energy system with multi-zone heat-suply network interaction compared to the single area CCHP model improved the clean energy utilization of the system, rationally allocates equipment capacity, promotes the local consumption of distributed energy, and provides better overall system benefits.
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Rodriguez, C. O., A. I. Liechtenstein, I. I. Mazin, O. Jepsen, O. K. Andersen, and M. Methfessel. "Optical near-zone-center phonons and their interaction with electrons inYBa2Cu3O7: Results of the local-density approximation." Physical Review B 42, no. 4 (August 1, 1990): 2692–95. http://dx.doi.org/10.1103/physrevb.42.2692.
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Nygren, Garrett, and Ryan L. Karkkainen. "Simulation of anisotropic crack tip deformation processes and particle interactions in toughened polymers." Polymers and Polymer Composites 28, no. 1 (June 19, 2019): 3–13. http://dx.doi.org/10.1177/0967391119856168.
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This study develops a finite element-based simulation of submicrometer crack tip deformation processes in polymers to investigate local toughening effects. An initial study of how these processes interact with stiff inclusions is presented to enable further investigation of particulate toughening. Crack tip and process zone mechanisms, including polymer chain disentanglement, directional chain realignment with consequent anisotropy, and crack propagation, are considered in a dedicated user-defined material law. Such processes are generally homogenized on higher scale continuum levels analyses, but direct simulation can provide insight into toughening mechanisms that have been widely observed but not fully explained. The user material law herein was employed in a parametric study to investigate the relative importance of (1) the extent of local inelastic polymer chain realignment and (2) consequent anisotropic hardening of the realigned polymer chains. In order to explore the interaction of fracture processes with nanometer-scale inclusions, silica particles with varied spacing were also included in the simulations. The interaction between local stress concentration and energy dissipation mechanisms has been quantified. It is shown that in neat polymers, local yielding is the dominant toughening effect accounting for over 90% of the local energy absorption, whereas local stiffening alone would decrease toughness. Stiff inclusions were shown to generally decrease toughness, except in cases where local yielding greatly outweighs local stiffening effects. Roughly 45% increase in toughness was shown for a 250-nm particle spacing that balances the acceleration of elastic failure with the formation of a larger local yield zone size. This demonstrates the utility of employing dedicated material laws to microstructural scale analyses in providing design targets in material design.
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Ye, Shen, Xian Cheng Zhang, and Shan Tung Tu. "Interaction between Local Plastic Strain and Multi-Scale Fatigue Crack Propagation Behavior in Titanium Alloy TC4." Applied Mechanics and Materials 853 (September 2016): 51–56. http://dx.doi.org/10.4028/www.scientific.net/amm.853.51.
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Multi-scale Fatigue crack growth behavior of titanium alloy TC4 under different maximum stress was identified in the present work by using an in-situ fatigue testing system. Results showed that specimen tested at lower maximum stress exhibited longer fatigue life, since the small fatigue crack stage accounted for a larger fraction of the total fatigue life. Local deformation around fatigue crack was measured by digital image correlation (DIC) technique. The evolution of multi-scale fatigue crack was identified. Relationship between size of plastic zone and crack growth rate was identified.
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Garcia-Bach, M. A., D. J. Klein, and R. Valenti. "TRANSFER-MATRIX METHOD FOR SOLVING THE SPIN 1/2 ANTIFERROMAGNETIC HEISENBERG CHAIN." International Journal of Modern Physics B 02, no. 05 (October 1988): 1035–36. http://dx.doi.org/10.1142/s021797928800086x.
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Following the discovery of high Tc superconductivity in the copper oxides, there has been a great deal of interest in the RVB wave function proposed by Anderson [1]. As a warm-up exercise we have considered a valence-bond wave function for the one dimensional spin-1/2 Heisenberg chain. The main virtue of our work is to propose a new variational singlet wavefunction which is almost analytically tractable by a transfer-matrix technique. We have obtained the ground state energy for finite as well as infinite chains, in good agreement with exact results. Correlation functions, excited states, and the effects of other interactions (e.g., spin-Peierls) are also accessible within this scheme [2]. Since the ground state of the chain is known to be a singlet (Lieb & Mattis [3]), we write the appropriate wave function as a superposition of valence-bond singlets, [Formula: see text], where | k > is a spin configuration obtained by pairing all spins into singlet pairs, in a way which is common in valence-bond calculations of large molecules. As in that case, each configuration, | k >, can be represented by a Rümer diagram, with directed bonds connecting each pair of spins on the chain. The c k 's are variational co-efficients, the form of which is determined as follows: Each singlet configuration (Rümer diagram) is divided into "zones", a "zone" corresponding to the region between two consecutive sites. Each zone is indexed by its distance from the end of the chain and by the number of bonds crossing it. Our procedure assigns a variational parameter, x ij , to the j th zone, when crossed by i bonds. The resulting wavefunction for an N-site chain is written as [Formula: see text] where m ij(k) equals 1 when zone j is crossed by i bonds and zero otherwise. To make the calculation tractable we reduce the number of variational parameters by disallowing configurations with bonds connecting any two sites separated by more than 2M lattice points. (For simplicity, we have limited ourselves to M=3, but the scheme can be used for any M). With the simple ansatz, matrix elements can be calculated by a transfer-matrix method. To understand the transfer-matrix method note that since only local zone parameters appear in the description of each state | k >, matrix elements and overlaps, [Formula: see text] and < k | k '>, are completely specified by a small number of "local states" associated with each zone. Within a given zone a local state is defined by (i) the number of bonds crossing the zone and (ii), by whether the bonds originate from the initial (| k >) or final (| k '>) state. It is then easy to see that "local states" of consecutive zones are connected by a 15 × 15 transfer matrix (for the case M=3). Furthermore, the overlap matrix element can be written as a product of transfer-matrices associated with each zone of the chain. When calculating matrix elements of the Hamiltonian, an additional matrix, U , must be defined, to represent the particular zone involving the two spins connected by the Heisenberg interaction. The relevant details as well as the comparison with exact results will be given elsewhere. We are planning to ultimately apply this method to the two dimensional case, and hope to include the effects of holes.
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Поливанов, П. А., and А. А. Сидоренко. "Подавление ламинарной отрывной зоны искровым разрядом при числе Маха M = 1.43." Письма в журнал технической физики 44, no. 18 (2018): 60. http://dx.doi.org/10.21883/pjtf.2018.18.46613.17344.
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AbstractThe influence of flow perturbations generated by an electric discharge on the region of interaction between a shock wave and laminar boundary layer in the flow on a flat plate at a Mach number of M = 1.43 has been experimentally studied. The oblique shock wave generated by a wedge mounted above the plate induced separation of the flow, while perturbations in the flow were introduced by a spark discharge on the model plate surface. It is established that the discharge leads to the formation of turbulent and thermal spots. The turbulent spot suppresses the separation zone, while the thermal spot leads to a local increase in the boundary layer thickness in the interaction zone.
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Joshi, Dipesh. "Community Based Conservation: Redefining Boundaries." Journal of Forest and Livelihood 14, no. 1 (August 31, 2016): 1–12. http://dx.doi.org/10.3126/jfl.v14i1.23157.
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Conservation and management of biodiversity is complex and a localized phenomenon in the Terai Arc Landscape (TAL) which is inhabited by 7.4 million people out of which 25 per cent are still below the poverty line. There is significant interaction between the human and natural resources with diverse values of biodiversity and ecosystem services to the local populations. The implications of variations in terms of dependence on natural resources are that conservation and management strategies broadly vary across the landscape. Success and failures of conservation strategy/approach cannot commonly be extrapolated across this diverse landscape. While many projects in TAL have failed, some have succeeded too and is shaped by multiple factors including the type and level of human interactions with biodiversity. This review article provides reflections on experiences of decades of Community Based Conservation (CBC) in Nepal with a specific focus on Chitwan National Park and its buffer zone located in TAL. CBC confronts newer challenges and issues pertaining to inadequate mechanisms to address communities beyond buffer zones in a scenario where conservation needs to move beyond the conventional boundaries of parks and buffer zones, equitable benefit sharing, inequalities within communities, increasing human-wildlife conflicts, ecotourism, nexus of poverty-livelihood and conservation. However, CBC offers greater potentials and opportunities for greater local community engagement in a changing context to reconcile local development with conservation.
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Chen, Bin, Xinghua Shi, and Huajian Gao. "Apparent fracture/adhesion energy of interfaces with periodic cohesive interactions." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 464, no. 2091 (December 18, 2007): 657–71. http://dx.doi.org/10.1098/rspa.2007.0240.
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The apparent fracture/adhesion energy of an interface with periodic cohesive interactions is of general interest to understanding adhesion via periodic adhesion patches (e.g. between micro- and nanostructured surfaces). There are two important length scales for this class of problems: one corresponds to the period of cohesive interaction and the other is the size of the cohesive zone near the tip of a crack along the interface. By theoretical considerations and numerical simulations, we show that the apparent fracture/adhesion energy depends on the ratio between the period of cohesive interaction and the cohesive zone size: it is equal to the average cohesive energy of the interface if the former is much smaller than the latter but becomes the peak value of the local cohesive energy when the opposite is true. This prediction has been confirmed by numerical simulations on the peeling of a thin-film/strip adhering on a substrate via periodic discrete adhesion patches. Our analysis also provides explanations for a recent molecular dynamics simulation which showed that the apparent adhesion energy of a single-stranded DNA (ssDNA) adhering on a graphite sheet is equal to the peak, rather than the average, value of the van der Waals interaction energy between the ssDNA and the substrate.
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Pasichnyy, Mykola, and Andriy Gusak. "Modeling of Phase Competition and Diffusion Zone Morphology Evolution at Initial Stages of Reaction Diffusion." Defect and Diffusion Forum 237-240 (April 2005): 1193–98. http://dx.doi.org/10.4028/www.scientific.net/ddf.237-240.1193.
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The initial stages of reactive diffusion have been studied by Monte-Carlo simulations. New MC-scheme describing the competition of two ordered intermediate phases is proposed. Main peculiarity of presented MC-model is a strong dependence of interatomic interaction energies on the local atomic surrounding, enabling us to distinguish new phases more distinctly.
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Karkhut, Ihor. "Determining the stressed-strained state of concrete in the zone of exposure to local laser radiation." Eastern-European Journal of Enterprise Technologies 3, no. 7 (111) (June 30, 2021): 24–36. http://dx.doi.org/10.15587/1729-4061.2021.232671.
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This paper reports the results of the physical and numerical experiments on determining the stressed-strained state of concrete in protective structures in the region of the effect of local point laser radiation. The software package LIRA10.8 (release 3.4) was used to build a computer model in the statement of a stationary thermal conductivity problem. To this end, the findings from the experimental studies were applied – the resulting temperature distribution and changes in the structure of concrete on the surface and deep into concrete cubes for more than 120 samples of concrete with three levels of moisture content: dried, natural humidity, and water-saturated. This paper gives the parameters of the simulation, the results of a numerical experiment, their analysis, and comparison with the results of a physical experiment. The temperature fields when establishing the dynamic temperature equilibrium, the level of stresses in concrete, derived from the physical experiments, correlate well with the results of the numerical experiment. The maximum temperature determined by the optical method at the surface of concrete was 1,350+50 °С. Deviations at control points do not exceed 12–70 °С in the temperature effect zone and 18–176 °С (1–11 %). At the rated radiation power of 30 W, the second stage of interaction was achieved; at 100 W – the fourth stage for concrete with a moisture content of 0–2.5 %; and, for water-saturated concrete, the fifth stage of interaction with the laser beam. A significant decrease in the thresholds between the stages of interaction between laser radiation and concrete was revealed, especially water-saturated concrete, compared to the thresholds for metals (the thresholds between the third and fifth stages were reduced by 103–104 times). The destruction of the walls of water-saturated pores in concrete occurred under the pressure of water vapor. The tangent stresses, in this case, were 1.7 MPa, and the values for the coefficient Kр, determined by the method of acoustic emission, were in the range of 4‒6. Such results explain the absence of normal microcracks due to the hoop effect. It was established that in the contact zone between a laser beam and concrete, about 90 % of the radiation energy dissipates, and in the adjacent heating zone ‒ up to 77 %. The optimal speed of beam movement when cleaning the concrete surface from organic, paint, and other types of contamination of 0.5–2 mm/s (surface temperature, 100–300 °С) has been proposed
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Du, Min, Changsui Zhao, Bin Zhou, and Yingli Hao. "DSMC Prediction of Particle Behavior in Gas-Particle Two-Phase Impinging Streams." Mathematical Problems in Engineering 2013 (2013): 1–11. http://dx.doi.org/10.1155/2013/254082.
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Devices with impinging streams have been employed in various fields of chemical engineering, as a means of intensifying heat and mass transfer processes. The particle behavior in gas-particle two-phase impinging streams (GPISs), which is of essential importance for the research of transfer processes, was simulated by an Eulerian-Lagrangian approach in this paper. Collisional interaction of particles was taken into account by means of a modified direct simulation Monte Carlo (DSMC) method based on a Lagrangian approach and the modified Nanbu method. A quantitative agreement was obtained between the predicted results and the experimental data in the literature. The particle motion behavior and the distributions of particle concentration and particle collision positions were presented reasonably. The results indicate that the particle distribution in GPIS can be divided into three zones: particle-collision zone, particle-jetting zone, and particle-scattering zone. Particle collisions occur mainly in the particle-collision zone, which obviously results in a few particles penetrating into the opposite stream. The interparticle collision rate and the particle concentration reach their maximum values in the particle-collision zone, respectively. The maximum value of the particle concentration increases with the increasing inlet particle concentration according to a logarithmic function. The interparticle collision rate is directly proportional to the square of local particle concentration.
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Hård, Mikael, and Mai Lin Tjoa-Bonatz. "Trading zones in a colony: Transcultural techniques at missionary stations in the Dutch East Indies, 1860 – 1940." Social Studies of Science 50, no. 6 (May 24, 2020): 932–55. http://dx.doi.org/10.1177/0306312720925913.
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Global histories of technology tend to tell one-sided stories of transfer and exploitation, and they usually analyze the activities of large corporations, nation states or the military. By focusing on missionary societies in the colonial era, this article tells a different story. On the basis of primary sources from German missionaries in the Dutch East Indies, it shows how the application of various techniques at missionary stations was the outcome of transcultural interaction. Although missionaries brought with them tools and materials from home, they remained dependent on the knowledge and skills of local artisans, as well as the material and goods the locals provided. Missionaries’ wives tried to uphold a Western lifestyle but found themselves using local household technologies. The missionary station was a trading zone: Although the abilities of Europeans and Asians to communicate were socially and linguistically limited, they proved able to exchange information and skills in a successful manner. By revisiting the anthropological background to Galison’s trading zone, the authors re-appropriate this concept to improve our understanding of cross-cultural exchange in non-scientific settings.
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Jacak, Janusz. "Topological Classification of Correlations in 2D Electron Systems in Magnetic or Berry Fields." Materials 14, no. 7 (March 27, 2021): 1650. http://dx.doi.org/10.3390/ma14071650.
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Recent topology classification of 2D electron states induced by different homotopy classes of mappings of the planar Brillouin zone into Bloch space can be supplemented by a homotopy classification of various phases of multi-electron homotopy patterns induced by Coulomb interaction between electrons. The general classification of such type is presented. It explains the topologically protected correlations responsible for integer and fractional Hall effects in 2D multi-electron systems in the presence of perpendicular quantizing magnetic field or Berry field, the latter in topological Chern insulators. The long-range quantum entanglement is essential for homotopy correlated phases in contrast to local binary entanglement for conventional phases with local order parameters. The classification of homotopy long-range correlated phases induced by the Coulomb interaction of electrons has been derived in terms of homotopy invariants and illustrated by experimental observations in GaAs 2DES, graphene monolayer, and bilayer and in Chern topological insulators. The homotopy phases are demonstrated to be topologically protected and immune to the local crystal field, local disorder, and variation of the electron interaction strength. The nonzero interaction between electrons is shown, however, to be essential for the definition of the homotopy invariants, which disappear in gaseous systems.
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Korre, L., NH Brummell, P. Garaud, and C. Guervilly. "On the dynamical interaction between overshooting convection and an underlying dipole magnetic field – I. The non-dynamo regime." Monthly Notices of the Royal Astronomical Society 503, no. 1 (February 18, 2021): 362–75. http://dx.doi.org/10.1093/mnras/stab477.
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ABSTRACT Motivated by the dynamics in the deep interiors of many stars, we study the interaction between overshooting convection and the large-scale poloidal fields residing in radiative zones. We have run a suite of 3D Boussinesq numerical calculations in a spherical shell that consists of a convection zone with an underlying stable region that initially compactly contains a dipole field. By varying the strength of the convective driving, we find that, in the less turbulent regime, convection acts as turbulent diffusion that removes the field faster than solely molecular diffusion would do. However, in the more turbulent regime, turbulent pumping becomes more efficient and partially counteracts turbulent diffusion, leading to a local accumulation of the field below the overshoot region. These simulations suggest that dipole fields might be confined in underlying stable regions by highly turbulent convective motions at stellar parameters. The confinement is of large-scale field in an average sense and we show that it is reasonably modelled by mean-field ideas. Our findings are particularly interesting for certain models of the Sun, which require a large-scale, poloidal magnetic field to be confined in the solar radiative zone in order to explain simultaneously the uniform rotation of the latter and the thinness of the solar tachocline.
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Sysyn, Mykola, Michal Przybylowicz, Olga Nabochenko, and Jianxing Liu. "Mechanism of Sleeper–Ballast Dynamic Impact and Residual Settlements Accumulation in Zones with Unsupported Sleepers." Sustainability 13, no. 14 (July 11, 2021): 7740. http://dx.doi.org/10.3390/su13147740.
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Unsupported sleepers or void zones in ballasted tracks are one of the most recent and frequent track failures. The void failures have the property of intensive development that, without timely maintenance measures, can cause the appearance of cost-expensive local instabilities such as subgrade damages. The reason for the intensive void development lies in the mechanics of the sleeper and ballast bed interaction. The particularity of the interaction is a dynamic impact that occurs due to void closure. Additionally, void zones cause inhomogeneous ballast pressure distribution between the void zone and fully supported neighbour zones. The present paper is devoted to studying the mechanism of the sleeper–ballast dynamic impact in the void zone. The results of experimental in situ measurements of rail deflections showed the significant impact accelerations in the zone even for lightweight slow vehicles. A simple three-beam numerical model of track and rolling stock interaction has shown dynamic interaction similar to the experimental measurements. Moreover, the model shows that the sleeper accelerations are more than 3 times higher than the corresponding wheel accelerations and the impact point appears before the wheel enters the impact point. The analysis of ballast loadings shows the specific impact behaviour in combination with the quasistatic part that is different for void and neighbour zones, which are characterised by high ballast pre-stressed conditions. The analysis of void size influence demonstrates that the maximal impact loadings and maximal wheel and sleeper accelerations appear at a certain void depth, after which the values decrease. The ballast quasistatic loading analysis indicates an increase of more than 2 times in the ballast loading in neighbour zones for long voids and almost full quasistatic unloading for short-length voids. However, the used imitation model cannot explain the nature of the dynamic impact. The mechanism of the void impact is clearly explained by the analytic solution using a simple clamped beam. A simplified analytical expression of the void impact velocity shows that it is linearly related to the wheel speed and loading. The comparison to the numerically simulated impact velocities shows a good agreement and the existence of the void depth with the maximal impact. An estimation of the long-term influences for the cases of normal sleeper loading, high ballast pre-stress and quasistatic loading in the neighbour zones and high impact inside the void is performed.
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VASTERLING, JENNIFER J., LISA M. DUKE, HOLLY TOMLIN, NATASHA LOWERY, and EDITH KAPLAN. "Global–local visual processing in posttraumatic stress disorder." Journal of the International Neuropsychological Society 10, no. 5 (September 2004): 709–18. http://dx.doi.org/10.1017/s1355617704105031.
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The purpose of this study was to examine a behavioral index of hemispheric asymmetry (i.e., visual hierarchical attention) in posttraumatic stress disorder (PTSD), a disorder characterized by anxiety and other emotional symptoms. A reaction time based, computerized, global–local visual paradigm was administered to 26 PTSD-diagnosed and 22 psychopathology-free right-handed, male Vietnam War zone veterans. Results indicated that PTSD-diagnosed veterans displayed slower reaction times to all targets than the no-mental disorders comparison sample. However, findings also revealed a Group × Target location interaction in which the PTSD group was slower than the no-disorders comparison sample to respond to local, but not global, targets. Moreover, relative global bias was greater among PTSD-diagnosed veterans than their no-diagnosis counterparts. Findings provide partial support for the hypothesis that PTSD may be associated with a functional cerebral asymmetry favoring the right hemisphere. (JINS, 2004,10, 709–718.)
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GUD’, Ilya D. "DEVELOPMENT OF RESOURCE POTENTIAL OF URBAN PLANNING RESERVES IN MEGAPOLISES." Urban construction and architecture 10, no. 2 (June 15, 2020): 116–23. http://dx.doi.org/10.17673/vestnik.2020.02.16.
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The article shows the results of theoretical research in the fi eld of spatial development of the territory and the sett lement. Infrastructure provision of the forming Greater Samara megapolis is considered in the dialectical confrontation of internal and external infl uence factors in relation to the global transport map. The practical proposals for the territorial sett lement formation system of Samara province based on the development of towns interaction in the structure of the marginal zone of Samara agglomeration with peripheral local systems of rural sett lement are made. The author makes models of multi-modal transport and logistics hubs (Multihubs) in promising “growth poles”, which are going to be at the points of contact of the peripheral marginal zone of the Samara agglomeration with local rural settlement systems.
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Kortikov, Nicolay. "Simulation of the joint effect of rotor-stator interaction and circumferential temperature unevenness on losses in the turbine stage." MATEC Web of Conferences 245 (2018): 04006. http://dx.doi.org/10.1051/matecconf/201824504006.
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The article devotes to problems of unsteady interaction of the hot streams downstream of the combustion chamber with the rotating blades of the rotor wheel. The hot streams downstream of the combustion chamber are caused by discrete circumferentially located fuel nozzles and openings for air supply to the combustion chamber mixing zone. Unsteady interaction of the hot streams with the rotating blades of the rotor wheel leads to local redistribution of the time average gas flow temperature which has effect on the blade – “temperature segregation”.
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Kortikov, Nicolay. "Simulation of the joint effect of rotor-stator interaction and circumferential temperature unevenness on losses in the turbine stage." MATEC Web of Conferences 245 (2018): 06008. http://dx.doi.org/10.1051/matecconf/201824506008.
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The article devotes to problems of unsteady interaction of the hot streams downstream of the combustion chamber with the rotating blades of the rotor wheel. The hot streams downstream of the combustion chamber are caused by discrete circumferentially located fuel nozzles and openings for air supply to the combustion chamber mixing zone. Unsteady interaction of the hot streams with the rotating blades of the rotor wheel leads to local redistribution of the time average gas flow temperature which has effect on the blade – “temperature segregation”.
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Pasquali, Davide, and Alessandro Marucci. "The Effects of Urban and Economic Development on Coastal Zone Management." Sustainability 13, no. 11 (May 28, 2021): 6071. http://dx.doi.org/10.3390/su13116071.
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The land transformation process in the last decades produced the urbanization growth in flat and coastal areas all over the world. The combination of natural phenomena and human pressure is likely one of the main factors that enhance coastal dynamics. These factors lead to an increase in coastal risk (considered as the product of hazard, exposure, and vulnerability) also in view of future climate change scenarios. Although each of these factors has been intensively studied separately, a comprehensive analysis of the mutual relationship of these elements is an open task. Therefore, this work aims to assess the possible mutual interaction of land transformation and coastal management zones, studying the possible impact on local coastal communities. The idea is to merge the techniques coming from urban planning with data and methodology coming from the coastal engineering within the frame of a holistic approach. The main idea is to relate urban and land changes to coastal management. Then, the study aims to identify if stakeholders’ pressure motivated the deployment of rigid structures instead of shoreline variations related to energetic and sedimentary balances. The influence of coastal protection (described by an indicator taking into account the linear density of the rigid protection extension alongshore) measures have been considered. Finally, the economical performances in the period just after the land transformation have been studied by means of a dimensionless index based on the concept of the local unit. The method has been applied to the case study of the Abruzzo Region. Results reveal a large urbanization growth and a generalized over-protection of the coast with a resulting spatial alternation of shoreline retreat and advance. On the other hand, the analysis of the local economy reveals that the presence of tourism activities does not necessarily lead to an increase in the local economy. Indeed, the most important improvement in local economies in the region can be associated with coastal stretches characterized by a high environmental value.
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Sarker, A., M. Singh, F. El-Ashkar, W. Erskine, and E. De-Pauw. "Approaches to rationalising selection of test environments for on-farm lentil variety trials in Mediterranean rainfed cropping systems." Australian Journal of Agricultural Research 58, no. 4 (2007): 335. http://dx.doi.org/10.1071/ar05418.
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This study focused on various approaches to rationalising the selection of test environments using on-farm trial data from 5 lentil (Lens culiniaris Medikus subsp. culinaris) genotypes. It was conducted over 3 years in 30 environments across 16 locations in Syria. There was maximum discrimination in the ratio of between-cluster to within-cluster variances, based on genotype yield responses to the environments. Four clusters represented the test locations, reflecting a gradient in the levels of yield and seasonal rainfall. We observed significant genotypic differences and genotype × environment interactions. Genotype × cluster interaction accounted for a substantial portion of the genotype × environment interaction. This supported a reduction in the number of test locations to evaluate genotype and environment interaction. Temporal interactions were either low or insignificant. The improved lines produced stable and significantly higher yields than the local cultivar. The structure of the clusters formed indicated the presence of research stations in each cluster. We recommend that locations for future on-farm testing should include one research location and a farmer field in each cluster (or the mega-zone) so formed. Climatic variables or geographical nearness cannot replace the role of genotype response when rationalising test locations.
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Krause, S., and A. Bronstert. "An advanced approach for catchment delineation and water balance modelling within wetlands and floodplains." Advances in Geosciences 5 (December 16, 2005): 1–5. http://dx.doi.org/10.5194/adgeo-5-1-2005.
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Abstract. Water balance of wetlands within lowland floodplains is strongly influenced by the temporally variable spatial extent of the interactions between groundwater and surface water. A robust algorithm will be introduced which makes it possible to delineate the interaction zone between the lowland river and the floodplain. This interaction zone is specified as the "Direct Catchment" which is defined by the part of the connected floodplain in which wetland water balance is mainly affected by the surface water dynamics of the adjacent river. The delineation algorithm is based on transfer functions which were assessed by local simulation results of the integrated water balance and nutrient dynamics model IWAN. The transfer functions are further determined by mean annual groundwater depths and by simulated groundwater dynamics. They are controlled by simulation results of the maximal transversal extent of surface water influence on groundwater stages. The regionalisation of the developed delineation algorithm leads to the specification of the maximal extent of groundwater - surface water - interaction processes along the river. By application of this approach to the Havel River basin, located within lowlands of Northeaster Germany, it was possible to specify a 998.1 km2 part of the floodplain which is directly connected with the surface waters and thus called the "Direct Catchment" of the Havel river. The IWAN model was applied to simulate the water balance of the floodplain. The simulation results prove the tight interaction between river and floodplain. It is shown that the spatially and temporally variable influences of the connected floodplain on the river discharge were only important during low discharge in summer.
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Evangelista, Dennis J., Dylan D. Ray, Sathish K. Raja, and Tyson L. Hedrick. "Three-dimensional trajectories and network analyses of group behaviour within chimney swift flocks during approaches to the roost." Proceedings of the Royal Society B: Biological Sciences 284, no. 1849 (February 22, 2017): 20162602. http://dx.doi.org/10.1098/rspb.2016.2602.
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Chimney swifts ( Chaetura pelagica ) are highly manoeuvrable birds notable for roosting overnight in chimneys, in groups of hundreds or thousands of birds, before and during their autumn migration. At dusk, birds gather in large numbers from surrounding areas near a roost site. The whole flock then employs an orderly, but dynamic, circling approach pattern before rapidly entering a small aperture en masse . We recorded the three-dimensional trajectories of ≈1 800 individual birds during a 30 min period encompassing flock formation, circling, and landing, and used these trajectories to test several hypotheses relating to flock or group behaviour. Specifically, we investigated whether the swifts use local interaction rules based on topological distance (e.g. the n nearest neighbours, regardless of their distance) rather than physical distance (e.g. neighbours within x m, regardless of number) to guide interactions, whether the chimney entry zone is more or less cooperative than the surrounding flock, and whether the characteristic subgroup size is constant or varies with flock density. We found that the swift flock is structured around local rules based on physical distance, that subgroup size increases with density, and that there exist regions of the flock that are less cooperative than others, in particular the chimney entry zone.
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Stenvall, C. A., A. Fagereng, J. F. A. Diener, C. Harris, and P. E. Janney. "Sources and Effects of Fluids in Continental Retrograde Shear Zones: Insights from the Kuckaus Mylonite Zone, Namibia." Geofluids 2020 (August 1, 2020): 1–21. http://dx.doi.org/10.1155/2020/3023268.
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Midcrustal rocks in retrograde metamorphic settings are typically H2O-undersaturated and fluid-absent and have low permeability. Exhumed continental retrograde faults, nonetheless, show evidence for the operation of fluid-mediated weakening mechanisms during deformation at midcrustal conditions. To explore the origin and effects of fluids in retrograde faults, we study the Kuckaus Mylonite Zone (KMZ), an exhumed crustal-scale, strike-slip shear zone in the southern Namibian Namaqua Metamorphic Complex. The KMZ deformed quartzofeldspathic migmatised gneisses at midcrustal retrograde conditions (450-480°C, 270-420 MPa) in the Mesoproterozoic, 40 Ma after granulite facies peak metamorphism at 825°C and 550 MPa. The mylonites contain fully hydrated retrograde mineral assemblages, predominantly adjacent to anastomosing high-strain zones, providing evidence of local H2O saturation and fluid presence during deformation. Whole rock and quartz vein δ18O values suggest that at least some of the fluids were meteoric in origin. The rocks across the shear zone retain the effect of different protoliths, implying little effect of fluid-rock interaction on whole rock major element chemistry. Together with a general scarcity of quartz veins, this suggests that fluid/rock ratios remained low in the KMZ. However, even small amounts of H2O allowed reaction weakening and diffusion-precipitation, followed by growth and alignment of phyllosilicates. In the ultramylonites, a fine grain size in the presence of fluids allowed for grain size sensitive creep. We conclude that the influx of even small volumes of fluids into retrograde shear zones can induce drastic weakening by facilitating grain size sensitive creep and retrograde reactions. In retrograde settings, these reactions consume fluids, and therefore elevated fluid pressures will only be possible after considerable weakening has already occurred. Our findings imply that the range of seismic styles recently documented at active retrograde transform faults may not require high fluid pressures but could also arise from other local weakening mechanisms.
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Lu, Rong, Fengshan Ma, Jie Zhao, Jianbo Wang, Guilin Li, and Bing Dai. "Monitoring and Analysis of Stress Distribution of the Interaction between Rock and Backfill and the Influence of Geometric Features of the Backfill Boundary." Advances in Civil Engineering 2021 (August 4, 2021): 1–14. http://dx.doi.org/10.1155/2021/6632884.
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Backfill mining methods are widely used in metal mines. The boundary part of the backfill has a direct effect on the local stability in mining engineering. The distribution of stress on the boundary part of the backfill and surrounding rock had their own features. To study the characteristics of stress distribution of backfill and surrounding rock on the boundary part, we conducted a field investigation, field monitoring, and numerical simulation. According to the underground monitoring, the overall characteristics of the boundary part of the backfill were that the accumulated horizontal stress was larger than the accumulated vertical stress on the deep sublevel and the accumulated horizontal stress was smaller on the shallow sublevel. On the contact zone (i.e., the boundary part), the stress of the surrounding rock was larger than the stress of the backfill. Combined with the numerical model analysis, we determined that the geometric features of the backfill boundary had an influence on the stress distribution of stress. The multistep boundary helped the integrity of the contact zone and local stability in deep mining.
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Idowu, E. O. "Land use conflict between crop and livestock producers in the Guinea Savannah Zone of Nigeria." Nigerian Journal of Animal Production 29, no. 2 (January 1, 2021): 234–44. http://dx.doi.org/10.51791/njap.v29i2.1567.
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The paper examines the implications of property rights on land use conflict resolution between crop farmers and nomads in the guinea savannah zone of Nigeria and the methods of resolving the conflicts. Primary data were obtained from 200 randomly selected crop farmers and 75 nomadic Fulani's in four states within the zone, together with 25 key informants. Descriptive statistics were used to analyse the data. Highest levels of conflicts were recorded during the dry season (October March) when mobile herds migrate into the zone in search of pasture and water. Lack of official grazing routes caused the mobile herds to trespass on cultivated lands where growing or unharvested mature crops stood. Eight percent (8%) of past conflicts were perceived by the respondents as severe, involving use of dangerous weapons, loss of cattle and human lives. Increased social and economic interaction in Yorm of joint celebration of religious and social festivals (by 40% of nomads) with the local people and trade in cattle products and staple food items were found to be evolving over the local people and trade users. The study recommends the establishment of grazing routes within the zone while efforts should be made to enable the traditional institutions to function alongside legislation in resolving land use conflicts.
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Voropayeva, O. F., and G. G. Chernykh. "Numerical modeling of interaction between a turbulent mixing zone and a local perturbation of the density field in a pycnocline." Journal of Applied Mechanics and Technical Physics 51, no. 2 (March 2010): 182–92. http://dx.doi.org/10.1007/s10808-010-0027-9.
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Shcherbakov, S. A. "Shock wave formation as a result of interaction with a weak discontinuity on the boundary of a local subsonic zone." Fluid Dynamics 25, no. 4 (1991): 623–29. http://dx.doi.org/10.1007/bf01049873.
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Gilabert, Joan, Anna Deluca, Dirk Lauwaet, Joan Ballester, Jordi Corbera, and Maria Carmen Llasat. "Assessing heat exposure to extreme temperatures in urban areas using the Local Climate Zone classification." Natural Hazards and Earth System Sciences 21, no. 1 (January 28, 2021): 375–91. http://dx.doi.org/10.5194/nhess-21-375-2021.
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Abstract. Trends of extreme-temperature episodes in cities are increasing (in frequency, magnitude and duration) due to regional climate change in interaction with urban effects. Urban morphologies and thermal properties of the materials used to build them are factors that influence spatial and temporal climate variability and are one of the main reasons for the climatic singularity of cities. This paper presents a methodology to evaluate the urban and peri-urban effect on extreme-temperature exposure in Barcelona (Spain), using the Local Climate Zone (LCZ) classification as a basis, which allows a comparison with other cities of the world characterised using this criterion. LCZs were introduced as input of the high-resolution UrbClim model (100 m spatial resolution) to create daily temperature (median and maximum) series for summer (JJA) during the period 1987 to 2016, pixel by pixel, in order to create a cartography of extremes. Using the relationship between mortality due to high temperatures and temperature distribution, the heat exposure of each LCZ was obtained. Methodological results of the paper show the improvement obtained when LCZs were mapped through a combination of two techniques (land cover–land use maps and the World Urban Database and Access Portal Tools – WUDAPT – method), and the paper proposes a methodology to obtain the exposure to high temperatures of different LCZs in urban and peri-urban areas. In the case of Barcelona, the distribution of temperatures for the 90th percentile (about 3–4 ∘C above the average conditions) leads to an increase in the relative risk of mortality of 80 %.
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Chabaat, M., S. Djouder, and M. Touati. "Semi Empirical Stress Analysis of a Brittle Material in a Vicinity of a Stress Concentrator." Applied Mechanics and Materials 3-4 (August 2006): 243–52. http://dx.doi.org/10.4028/www.scientific.net/amm.3-4.243.
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In this study, interaction of a main crack with its surrounding damage, which consists of continuous lines of discontinuities, is analysed. To solve this complex problem, a Semi-Empirical Approach (SEA), which relies on experimentally measured crack opening displacements as the solution to this multiple crack interaction problem is suggested. The solution procedure is illustrated, first, for a particular case of the interaction of an array of horizontal and vertical crazes with a main crack, and second, for the generalized case to include the whole damage of crazing patterns surrounding the main crack. The results show that the crack Damage Zone (DZ) or the socalled Process Zone (PZ) interaction may either amplify or suppress the resulting stress field depending on the crack damage configuration. Green’s function for the Stress Intensity Factor (SIF) is employed to quantify the effects on a crack of the damage of continuous patterns of discontinuities. It follows from the analysis that an increase in the number of crazing patterns will amplify the stress at the main crack. It is also shown throughout this study that the overall effect of the damage is identified, as being an amplifying one and that the resulting local stress field would direct the propagation of the main crack since there is no toughening.
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Sahib, Rahmawansyah, Najiba Nawing, Hamra Sari, and Syamsir Bin Ukka. "West Papuan Teachers’ Perceptions on Translanguaging Practices in EFL Classroom Interaction." ELT-Lectura 7, no. 2 (August 20, 2020): 73–84. http://dx.doi.org/10.31849/elt-lectura.v7i2.4205.
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The belief that the West Papuan teachers applied translanguaging practice as strategy to enhance their students in ELT classroom. This study, investigated the West Papuan EFL teachers’ perceptions on translanguaging practices. It focused to explore the teachers’ knowledge and the teachers’ experience on translanguaging practice in EFL Classroom interaction in West Papuan. The participants of the study were three English language teachers (EFL) who work at state Islamic junior high school of Manokwari in West Papuan. The utterances of teachers’ interview were analyzed descriptive qualitatively using discourse analysis and the data gathered from classroom observations and semi-structured interviews were exposed to structural-coding analysis. The results showed that the EFL teachers have some perceptions about knowledge on translanguaging practice. There were translanguaging is a combination of Indonesian and English in the ELT Classroom, Translanguaging is a material transfer tool, Translanguaging is a safe and productive zone for students to do communication, Translanguaging is the moment for using mother tongue and local language in explaining material, Translanguaging is a strategy to improve and facilitate the understanding of material, Translanguaging is a strategy to enliven the classroom atmosphere. The EFL teachers also have experiences to apply translanguaging practice in ELT classroom. They used translanguaging to appreciate students in process of asking and answer the questions, to facilitate the transfer of material toward students, to assist the students in apply the target language, to respect the students’ questions that use the local language, and translanguaging as a challenge for teachers to master the local language of students.
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Talebi, Farzad, and Junji Kiyono. "Comparison of 3D Solid and Beam–Spring FE Modeling Approaches in the Evaluation of Buried Pipeline Behavior at a Strike-Slip Fault Crossing." Energies 14, no. 15 (July 27, 2021): 4539. http://dx.doi.org/10.3390/en14154539.
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Validated 3D solid finite element (FE) models offer an accurate performance of buried pipelines at earthquake faults. However, it is common to use a beam–spring model for the design of buried pipelines, and all the design guidelines are fitted to this modeling approach. Therefore, this study has focused on (1) the improvement of modeling techniques in the beam–spring FE modeling approach for the reproduction of the realistic performance of buried pipelines, and (2) the determination of an appropriate damage criterion for buried pipelines in beam–spring FE models. For this paper, after the verification of FE models by pull-out and lateral sliding tests, buried pipeline performance was evaluated at a strike-slip fault crossing using nonlinear beam–spring FE models and nonlinear 3D solid FE models. Material nonlinearity, contact nonlinearity, and geometrical nonlinearity effects were considered in all analyses. Based on the results, pressure and shear forces caused by fault movement and pipeline deformation around the high curvature zone cause local confinement of the soil, and soil stiffness around the high curvature zone locally increases. This increases the soil–pipe interaction forces on pipelines in high curvature zones. The beam–spring models and design guidelines, because of the uniform assumption of the soil spring stiffness along the pipe, do not consider this phenomenon. Therefore, to prevent the underestimation of forces on the pipeline, it is recommended to consider local increases in soil spring stiffness around the high curvature zone in beam–spring models. Moreover, drastic increases in the strain responses of the pipeline in the beam–spring model is a good criterion for a damage evaluation of the pipeline.