Journal articles on the topic 'Structure de zone de faille'
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1
Tremblay, Alain, Pierre St-Julien, and Jean-Yves Labbé. "Mise à l'évidence et cinématique de la faille de La Guadeloupe, Appalaches du sud du Québec." Canadian Journal of Earth Sciences 26, no. 10 (October 1, 1989): 1932–43. http://dx.doi.org/10.1139/e89-163.
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In the Appalachians of southern Quebec, the contact between Siluro-Devonian rocks of the Connecticut Valley – Gaspé Synclinorium and the Cambro-Ordovician rocks of the Dunnage Zone is marked by an important thrust fault striking northwest, La Guadeloupe fault. This fault separates two stratigraphically distinct domains, but the regional deformations are related to the same orogenic period. In the Sherbrooke and Weedon areas, different structural features show evidence of La Guadeloupe fault and reveal its kinematics. The exposed rocks near the fault exhibit structures that indicate a strong deformation zone. The deformation includes well-developed stretching lineations and shearing zones. The ductile deformation is restricted to the Cambro-Ordovician rocks. Macroscopic and microscopic studies of samples from the shear zones related to La Guadeloupe fault reveal, systematically, a tectonic transport from southwest to northwest. This interpretation is supported by the quartz crystallographic c-axis orientation. In New England, La Guadeloupe fault seems to coincide with the Taconic unconformity, though a bifurcation of the pre-Silurian units exposed on the western side of this unconformity remains possible. In Quebec, the correlation and kinematics of La Guadeloupe fault extension towards the northeast are not completely understood. [Journal Translation]
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Jang, Deh-Jeng, and J. David Frost. "Use of image analysis to study the microstructure of a failed sand specimen." Canadian Geotechnical Journal 37, no. 5 (October 1, 2000): 1141–49. http://dx.doi.org/10.1139/t00-031.
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The shearing of dilatant specimens of granular materials in the laboratory is often accompanied by the development of zones of more intense shearing. The nominal behavior of the specimens during this shearing condition is dictated by the behavior of soil particles inside the shear zones. To study the behavior of soil particles inside the shear zones, quantitative evaluation of the soil structure at the particulate scale is required. This paper describes the findings of a study that used digital image analysis to examine sand structure in a specimen where a shear zone formed. Evolution of the local void ratio distribution and changes in particle orientations within and adjacent to the shear zone were quantified.Key words: image analysis, sand, microstructure, shear, critical state.
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Gouze, Philippe, Riad Hassani, Dominique Bernard, and Anne Coudrain-Ribstein. "Calcul de l'evolution de la permeabilite des reservoirs sedimentaries contenant des argiles; application a la zone de la faille de Bray (bassin de Paris)." Bulletin de la Société Géologique de France 172, no. 4 (July 1, 2001): 427–36. http://dx.doi.org/10.2113/172.4.427.
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Abstract We propose a model for simulating the changes in porosity and permeability caused by hydrothermal diagenesis in sedimentary aquifer where salinity, temperature and fluid flow vary in space and time. Such modifications of the hydrodynamic properties of the medium are bounded to geochemical reactions and groundwater flow. Fluid velocity is particularly low in deep reservoirs (typically less than 1 m/year). Then, the local equilibrium simplification, which is justified by a set of world-wide data of the chemical composition of groundwater, can be implemented toward straightforward transient calculations. In the model presented here, the coupled processes of fluid flow, temperature and chemical species transport are solved using well established methods. The originality of the model is the development carried on to predict the permeability evolution controlled by the mineral dissolution and precipitation. Usually to simulate permeability changes modelers use the classical porosity-permeability model based on statistical analyses of in situ or laboratory measurements. However, hydraulic conductivity changes are not controlled solely by porosity changes, but also depend on pore-scale structure transformations. Depending on the mineral type, the precipitation or dissolution of the same quantity of volumetric quantity will induce very different changes in the hydraulic conductivity. Principally clay minerals depict a wide range of atypical organisations of different microstructural characteristics of the porous media. The spatial distribution of these characteristics cannot be modelled at basin scale. Away from both too complicated and too unrealistically simplified approach, the model presented here is based on the calculation of the permeability evolution from the change in the mineral fraction due to mineral precipitation and dissolution. To simplify, the minerals are divided into two groups: clay minerals and non-clay minerals. The specific contribution of clay minerals is controlled by a single weighting coefficient. This coefficient is associated to the proportion of poorly connected porosity that characterize clay structure, albeit it is presently impossible to propose any quantitative relationship between the value of this parameter and the microstructural characteristics of the diagenetic clays. The model is tested here to simulate the evolution of the porosity and the permeability in a peculiar zone of the Paris Basin. The study area of several hundred meters large is inside the Dogger aquifer, close to the Bray fault zone where invasion of saline water from Triassic formation takes place. This zone is characterised by high thermal and salinity gradient as well as by the superposition of sub-horizontal regional flow and ascendant fault-controlled flow: it is an ideal case study for examining the importance of taking into account the specific contribution by clay minerals when computing permeability evolution. This study is proposed as a parameter sensibility analysis: - to compare the relative influence of the clay weighting coefficient, the temperature, the salinity, and the cementation exponent on the computed evolution of the permeability, - to discuss the consequences of the introduction of the clay weighting coefficient in comparison to the classical porosity - permeability evolution model, - to simulate various evolution scenarios of past and future thermal and geochemical constraints and their consequences on the evolution of the permeability changes in the Bray fault zone taking into account uncertainties on the value of the clay weighting coefficient and on the cementation exponent. Forty-one simulations of one million years were necessary to cover a large spectrum of the expected variations of each parameter. The results show that: - the local variation of the permeability depends on the time evolution of temperature and of salinity, and on the values of the cementation exponent of the porosity-permeability law and of the clay weighting coefficient. Within reasonable ranges of these four parameters, their influence on the permeability changes is of the same order of magnitude, - the influence of the clay weighting coefficient on the porosity evolution is negligible. Feedback effects of permeability evolution on the porosity evolution, through the change in the flow regime, is minor, - by the use of a classical model without a clay weighting coefficient, permeability and porosity present the same pattern of evolution: they both increase or decrease. By the use of the clay weighting coefficient, in some places the permeability and porosity can show opposite evolution. One increases when the other decreases even for low values of the coefficient, - in the vicinity of the fault, the model predict an increase of permeability independently of potential temperature and salinity modifications and whatever the clay mineral weighting coefficient is: Bray fault sealing is unlikely as long as head gradient is maintained in the fracture zone.
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Lin, Jing-Yi, Jean-Claude Sibuet, Shu-Kun Hsu, Chao-Shing Lee, and Frauke Klingelhoefer. "Sismicité et volcanisme dans le Sud-Ouest du bassin arrière-arc d’Okinawa (Nord-Est Taiwan)." Bulletin de la Société Géologique de France 180, no. 2 (March 1, 2009): 155–70. http://dx.doi.org/10.2113/gssgfbull.180.2.155.
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Abstract La plupart des activités volcaniques observées dans le bassin arrière-arc d’Okinawa s’attachent à la subduction de la plaque des Philippines. Afin d’étudier les mécanismes liés à l’ouverture du bassin d’Okinawa, nous avons analysé les données provenant d’une campagne d’écoute passive de la sismicité et les données géophysiques existantes (données magnétiques et sismiques) en utilisant plusieurs méthodes. Les estimations des profondeurs du toit et de la base du socle magnétique en utilisant les données des anomalies magnétiques ont été effectuées dans le bassin d’Okinawa. La croûte est amincie le long du méridien 123,3oE et est épaissie sous la région volcanique du « cross backarc volcanic trail » (CBVT). La ride de Gagua située le long du méridien 123oE sépare le bassin de Huatung et le bassin ouest-Philippin. Les lithosphères de chaque côté de cette structure sont d’âges différents. L’angle de la plaque Philippine plongeante est plus fort à l’Ouest qu’à l’Est suggérant la présence d’une déchirure du slab des Ryukyus alignée le long de 123,3oE. De fin novembre à début décembre 2003, 15 OBSs ont été déployés dans le sud-ouest du bassin d’Okinawa. Plus de 3300 séismes ont été localisés, dont 20 enregistrés simultanément par les réseaux à terre. En analysant la répartition de 2823 séismes sélectionnés et relocalisés, quatre essaims de séismes ont été identifiés. La plupart des séismes se ré-partissent dans l’axe du bassin. La faille de Lishan, une structure géologique majeure à terre, se prolonge dans le bassin d’Okinawa jusqu’à 123,6oE. Au nord de l’extension de la faille de Lishan, peu de séismes sont enregistrés. En analysant les spectres de vitesse des ondes P, un groupe de séismes de basse fréquence a été identifié sous la chaîne de volcans CBVT, ce qui suggère une origine magmatique pour ces séismes. En partant des nombreux séismes enregistrés par les réseaux terrestres et pendant cette campagne, deux inversions tomographiques ont été réalisées. (1) A l’extrémité ouest du slab des Ryukyus, une zone d’anomalie de faibles vitesses Vp, Vs et de fort rapport Vp/Vs, de 30 km d’épaisseur en forme de saucisse a été localisée sur le rebord du slab, à une profondeur variant de 20 à 125 km. Elle correspond à une zone de fusion partielle ou enrichie en eau provenant de la déshydratation du slab. Un chenal remonte de cette anomalie depuis une profondeur de 40 km en direction de l’île andé-sitique de Kueishantao, matérialisant l’alimentation magmatique de cette île. (2) Dans le bassin d’Okinawa, trois trajectoires magmatiques caractérisées par de faibles vitesses Vp, Vs et un fort rapport Vp/Vs ont été localisées vers 50 km de profondeur, au niveau de la déchirure du slab: le chenal principal remonte en direction de la chaîne volcanique transver-sale (CBVT) située à l’axe du bassin ; le deuxième chenal remonte en direction de l’arc des Ryukyus et s’arrête à une profondeur de 30 km sous l’île d’Iriomote ; le troisième chenal remonte parallèlement à la déchirure du slab. En outre, une remontée asthénosphérique en forme de langue se dirige vers l’axe du bassin. Nous suggérons que la déchirure de la plaque permet la remontée de composants exotiques et/ou d’une source thermique anormale en provenance du manteau située sous la plaque subduite, ce qui se traduit par une augmentation de l’activité volcanique dans la région.
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Hossain, M., and W. Malalasekera. "Numerical study of bluff-body non-premixed flame structures using laminar flamelet model." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 219, no. 5 (August 1, 2005): 361–70. http://dx.doi.org/10.1243/095765005x28616.
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A laminar flamelet model is applied for bluff-body stabilized flames to study the flow field, mixing pattern, and the flame structure at two different velocities. The k - ɛ turbulence model is applied for accounting the turbulence fluctuations. It is found that the recirculation zone dominates the near field, while the far field structure is similar to the jet flow. The intermediate neck zone is the intense mixing region. The computation shows that the fuel jet velocity has significant effect on the structure of the flow field, which in turn has significant effect on the combustion characteristics. The laminar flamelet model is found to be adequate for simulating the temperature and the flame composition inside the recirculation zone. The flamelet model has, however, failed to account for the local extinction in the neck zone. Possible limitation of the laminar flamelet model to predict the local extinction is discussed.
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Kâ, S. L., Mamadou Ousseynou Ly, Mayécor Diouf, Mouhamadou Diandy, Moustapha Guéye, Mame Samba Mbaye, and Kandioura Noba. "Diversité herbacée dans les parcours du noyau de sélection du Centre de recherches zootechniques de Kolda en zone soudanienne du Sénégal." Revue d’élevage et de médecine vétérinaire des pays tropicaux 73, no. 3 (September 17, 2020): 199–205. http://dx.doi.org/10.19182/remvt.31891.
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Situé dans la zone soudanienne du Sénégal, le Centre de recherches zootechniques de Kolda est subdivisé en zone de parcours et en zone de cultures annuelles. Du fait de sa tolérance à la trypanosomose, la race Ndama est la seule race bovine qui fait l’objet d’étude de sélection dans le Centre. Cependant, on assiste depuis quelques années à une forte pression sur les zones de parcours liée à l’augmentation de la taille du troupeau et des superficies allouées aux cultures annuelles. Cela risque de réduire la diversité des espèces fourragères et ainsi d’impacter la performance génétique des animaux, compromettant les objectifs de sélection. Cette étude a eu pour objectif d’évaluer l’effet combiné du surpâturage et des activités agricoles sur la structure taxonomique de la végétation herbacée dans un système semi-extensif. Des relevés de végétation ont été effectués dans les différentes unités d’occupation du sol en fin de saison des pluies dans 75 placettes de 0,25 mètre carré. Ainsi, 69 espèces réparties dans 43 genres et 13 familles ont été inventoriées. La richesse spécifique a été plus importante dans les jachères, suivies des zones de parcours avec respectivement 36 et 26 espèces.m². La diversité spécifique a été faible dans les champs de légumineuses et les champs de coton. Dans les zones de parcours ont surtout dominé les Rubiaceae (Diodia sarmentosa, Spermacoce stachydea) et les Lamiaceae (Mesosphaerum suaveolens), familles de plantes à faible appétibilité, ainsi que des graminées à enracinement profond (Andropogon gayanus, Schizachyrium sanguineum). Les résultats ont révélé que le système d’exploitation des terres du Centre affectait négativement la composition et la diversité des herbacées et favorisait la prolifération des espèces faiblement appétées par les bovins.
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Garba, Amadou, Abdou Amani, Soumana Douma, Abdoul Kader Soumaila Sina, and Ali Mahamane. "Structure des populations de Tamarindus indica L. dans la zone Sud-Ouest du Niger." International Journal of Biological and Chemical Sciences 14, no. 1 (April 3, 2020): 126–42. http://dx.doi.org/10.4314/ijbcs.v14i1.11.
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L’état des populations de Tamarindus indica L. des zones sud-ouest du Niger a été établi à travers l’analyse de leur structure demographiques. L’étude a été conduite dans les communes rurales du département de Torodi, région de Tillabéry et de Bana et Tanda du département de Gaya, région de Dosso. Les données ont été collectées au moyen des relevés floristiques et des mesures de diamètres à 1,30 m pour les arbres et à 20 cm pour les arbustes et par le comptage des individus ayant un diamètre inférieur à 5 cm (d > 5 cm). Les résultats obtenus montrent que les densités de l’espèce au niveau des trois sites sont faibles et comprises entre 1 à 10 individus /ha, avec un taux de régénération nul. Les distributions observées des structures en diamètres et en hauteur s’ajustent avec les distributions théoriques de Weibull. Les valeurs du paramètre de forme C, supérieures à 3,6 (C > 3,6) pour les structures en diamètres, caractérisent une distribution asymétrique négative ou asymétrique gauche, caractéristique des peuplements monospécifiques à prédominance d’individus âgés.
© 2020 International Formulae Group. All rights reserved.
Mots clés: Tamarinsus indica, structure, populations, Niger
English Title: Demographical structure of the Tamarindus indica L. in southwest of Niger (north Soudan)
English Abstract
The status of Tamarindus indica populations in southwestern Niger has been established through the analysis of their population structure. The current study was conducted in the rural district of Torodi province, Tillabéry Region and the rural district of Bana and Tanda of Gaya province, Dosso Region. Data have been collected by means of floristic sampling, and measuring diameters of 1.3 meter for trees and 20 centimeters for shrubs, and counting species with less than five centimer diameters (d > 5 cm). The results have revealed that the density of the species at the three sites is lower and between 1 to 10 species per acre. The structure distributions observed in terms of diameter and height are in lign with Weibull theoretical distributions. The form C parameter is superior than 3.6 (C > 3.6) for the diameter structures, characterize a negative asymmetric or left asymmetric distribution, characteristic of monospecific stands with a predominance of older individual.
© 2020 International Formulae Group. All rights reserved.
Keywords: Tamarindus indica, structure, populations, Niger
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Buffin-Bélanger, T., A. G. Roy, and M. Levasseur. "Interactions entre les structures d'échappement et les structures à grande échelle dans l'écoulement turbulent des rivières à lit de graviers." Revue des sciences de l'eau 14, no. 3 (April 12, 2005): 381–407. http://dx.doi.org/10.7202/705425ar.
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Dans les rivières graveleuses, il est établi que les structures d'échappement formées dans la zone de recirculation à l'aval d'amas de galets génèrent d'intenses échanges turbulents. Le mécanisme responsable de l'échappement demeure par contre mal connu. Peu d'études sur la dynamique des structures d'échappement ont été réalisées dans des écoulements où le nombre de Reynolds est élevé comme c'est le cas en rivières. De plus, les connaissances actuelles ne tiennent pas compte des découvertes récentes sur la turbulence en rivière à lit de graviers où on a observé des structures de forte et de faible vitesse occupant toute la profondeur de l'écoulement et pouvant durer plusieurs secondes. Ces structures à grande échelle devraient jouer un rôle sur le mécanisme d'échappement étant donné l'influence de la vitesse ambiante sur la dynamique de la zone de recirculation. Nous rapportons les résultats de deux expériences originales sur les liens dynamiques entre les structures à grande échelle et le mécanisme d'échappement en aval d'un amas de galets. La première expérience repose sur l'analyse de corrélations croisées entre des séries de vitesses obtenues au sommet et à l'aval proximal d'un amas de galets. Les résultats montrent que les fortes fluctuations dans le sens de l'écoulement au sommet de l'obstacle sont liées, quelques instants plus tard, à de fortes fluctuations vers l'amont dans la zone de recirculation. La seconde expérience utilise la visualisation des structures d'échappement et la mesure simultanée des vitesses de l'écoulement. L'analyse combinée des images vidéo et de séries de vitesse suggère une relation entre le passage des structures à grande échelle et les manifestations de l'échappement. Ces résultats nous permettent de présenter un modèle où, lors du passage d'un front de haute vitesse, une structure d'échappement se développe et prend de l'expansion vers le lit et vers la surface en se propageant vers l'aval alors que, lors du passage d'un front de faible vitesse, elle s'élève vers la surface de manière plus cohérente. Cette étude propose un nouveau mécanisme d'échappement et révèle le rôle que joue la structure de l'écoulement ambiant sur le développement de structures dans les cours d'eau à lit graveleux.
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Ramezani, Hadi, Seyed Ali Asghar Akbari Mousavi, and Hossein Ebrahimzadeh. "The Effect of Process Parameters on Pulsed Nd:YAG Laser Welding of Inconel 625." Advanced Materials Research 829 (November 2013): 36–40. http://dx.doi.org/10.4028/www.scientific.net/amr.829.36.
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The bead on plate welding specimens with the 1mm thickness was fabricated by Nd:YAG pulsed laser SW-1 . The effects of laser process parameters on the weld dimensions, metallurgical and mechanical properties of weld metal were investigated. The results showed that both weld depth and weld width increase with voltage. Unlike base metal that has coaxial grain structure, weld metal is composed of a dendritic structure. Grain growth in the heat affected zone did not occur. However, ultrafine precipitations were deposited at the HAZ which their size was approximately between 500 nm to microns. All tensile specimens failed in the fusion zone.
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Johnston, Arch C., and Kaye M. Shedlock. "Overview of Research in The New Madrid Seismic Zone." Seismological Research Letters 63, no. 3 (July 1, 1992): 193–208. http://dx.doi.org/10.1785/gssrl.63.3.193.
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Abstract We review the development of understanding of the seismicity and tectonic structure of the New Madrid seismic zone and the upper Mississippi embayment. The broad framework of a failed intracontinental rift with reactivated seismogenic faults was not established until the mid-1970s. By the early 1990s a much more detailed knowledge of the rift and the current seismicity has been gained but fundamental questions remain. The 25 papers of this Special Issue of Seismological Research Letters convey the location of the most recent research front in such diverse fields as seismology, paleoseismology, seismic and potential-field investigation of rift structure, neotectonic deformation, and seismic hazard estimation and response. The new information content of these papers, considered ensemble, is enormous and highlights the tremendous progress made since the 1970s. These current studies, in turn, sharpen the focus on remaining outstanding problems of seismogenesis in the New Madrid seismic zone. We close with a discussion of what we believe will be the important foci of research in the 1990s.
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Chen, Yu, Huaying Li, Xiaoyu Wang, Hua Ding, and Fenghe Zhang. "A Comparative Investigation on Conventional and Stationary Shoulder Friction Stir Welding of Al-7075 Butt-Lap Structure." Metals 9, no. 12 (November 26, 2019): 1264. http://dx.doi.org/10.3390/met9121264.
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Both conventional friction stir welding (C-FSW) and stationary shoulder friction stir welding (S-FSW) were employed to join the Al-7075 butt-lap structure, then the microstructural evolution and mechanical characterization of all FSW joints were systematically studied. The C-FSW joint exhibited a rough surface with flashes and arc corrugations, while the surface of the S-FSW joint became smooth. Moreover, for the S-FSW joint, the shoulder-affected zone got eliminated and the material flow mode during FSW was changed owning to the application of stationary shoulder. Furthermore, in comparison to C-FSW, the lower welding heat input of S-FSW decreased the average grain size in the nugget zone and inhibited the coarsening of strengthening precipitates in the heat-affected zone, elevating the overall hardness for the S-FSW joint. In addition, the tensile strength of the S-FSW joint became higher compared to the C-FSW joint, and all the FSW joints failed inside the nugget zone attributing to the existence of hook defect. The sharp-angled hook defect deteriorated the plasticity of the C-FSW joint further, which was only 70% that of the S-FSW joint.
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Liu, Yutao, Chun-Feng Li, Yonglin Wen, Zewei Yao, Xiaoli Wan, Xuelin Qiu, Jia-zheng Zhang, Aqeel Abbas, Xi Peng, and Gang Li. "Mantle serpentinization beneath a failed rift and post-spreading magmatism in the northeastern South China Sea margin." Geophysical Journal International 225, no. 2 (January 11, 2021): 811–28. http://dx.doi.org/10.1093/gji/ggab006.
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SUMMARY The post-spreading magmatic activities in the northeastern South China Sea (SCS) margin are very strong, evidenced by widely distributed high-velocity lower crust (HVLC) and numerous volcanoes. However, there are large contrasts in magmatic activities and crustal structure between the Southern Depression (TSD) of the Tainan Basin and the volcanic continental slope area further south. We analyse their crustal P-wave velocity structures based on a newly acquired wide-angle ocean bottom seismic data set. The Cenozoic strata below the TSD, a Cenozoic failed rift, are relatively thick (∼3–4.5 km) with velocities from 1.6 to 3.6–3.9 km s–1, whereas the Mesozoic strata are relatively thin (∼1–2.5 km) with velocities from 4.3 to 4.6–5.2 km s–1. In the TSD, magmatic activities are relatively weak and the crust is severely thinned (∼4 km). The crust is 9–15 km thick below the volcanic continental slope area, which shows extensive volcanism. We identified HVLC below the failed rift of the TSD (Zone 1) and attributed it to mantle serpentinization, whereas the imaged HVLC below the volcanic continental slope (Zone 3) and HVLC adjacent to the failed rift of the TSD (Zone 2) are due to post-spreading magmatic underplating/intrusions. At the model distance ∼90 km, lateral transition from magmatic underplating/intrusions to mantle serpentinization occurred abruptly. We concur that post-spreading cooling and thermal contraction in the nearby SCS oceanic lithosphere can trigger decompressive melting and deformation in the thinned continental slope zone. Our study shows that, in addition to mantle serpentinization in the continent–ocean transition (COT) zone, mantle can also be serpentinized below the rift during early-stage rifting. Weak syn-rifting magmatism and mantle serpentinization below the failed rift support that the northeastern SCS has a magma-poor margin.
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Kemka, N., T. Njine, S. H. Zébazé Togouet, D. Niyitegeka, M. Nola, A. Monkiedje, J. Demannou, and S. Foto Menbohan. "Phytoplancton du lac municipal de Yaoundé (Cameroun) : Succession écologique et structure des peuplements." Revue des sciences de l'eau 17, no. 3 (April 12, 2005): 301–16. http://dx.doi.org/10.7202/705535ar.
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L'évolution spatio-temporelle, qualitative et quantitative du peuplement phytoplanctonique a été suivie au lac municipal de Yaoundé. Pour cela des prélèvements hebdomadaires ont été effectués de novembre 1996 à décembre 1997, au niveau d'une station de la zone centrale du lac.Trois descripteurs (indice de diversité spécifique, régularité et diagrammes rangs-fréquences) ont été utilisés pour l'analyse de la dynamique de la structure du peuplement. L'indice de diversité spécifique obtenu à partir des biomasses spécifiques, par la formule dérivée de celle de SHANNON et WEAVER (1949), est compris entre 0,68 et 4,64 bits/µg. La régularité (PIELOU, 1966) varie de 0,14 à 0,84; les faibles valeurs correspondant dans l'ensemble à la présence des espèces fortement dominantes. Les profils des diagrammes rangs-fréquences, établis en coordonnées log-log, associés aux faibles valeurs de la diversité, sont essentiellement caractéristiques des stades pionniers (1 et 1') de l'évolution d'un lac tel que décrits par MARGALEF (1967) et FRONTIER (1976). Le stade 2 est rare alors que le stade 3 est absent. Une analyse simultanée basée sur les variations spatio-temporelles de la densité cellulaire et de l'indice de diversité spécifique, sur les valeurs de la régularité, et sur les profils des diagrammes rangs-fréquences révèle le caractère immature permanent des populations phytoplanctoniques inféodées à ce biotope, et caractérise ainsi un milieu eutrophe à hypereutrophe où aucun stade d'équilibre n'est atteint. La richesse du milieu en éléments biogènes et sa faible profondeur (Zmax=4,3 m) sont à l'origine de sa vulnérabilité. L'événement susceptible d'interrompre la succession des populations s'est avéré être le brassage des eaux, provoqué aussi bien par les pluies que les vents dont l'énergie cinétique est fréquemment suffisante pour entraîner un brassage complet d'une colonne d'eau de hauteur aussi faible.
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Moulouel, Hakim, Luca Micarelli, Isabelle Moretti, and Djamel Machane. "Fracturation des carbonates dans la zone de faille normale active d’Aigion (Grèce) à partir des carottes du puits: conséquences sur les propriétés de transfert de fluides." Bulletin de la Société Géologique de France 186, no. 6 (October 1, 2015): 387–97. http://dx.doi.org/10.2113/gssgfbull.186.6.387.
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Abstract La faille d’Aigion appartient à un système de failles normales à pendage nord affectant la bordure sud du golfe de Corinthe, témoin d’une extension active d’échelle régionale caractérisant la région égéenne. Les carottes du forage AIG-10, qui a traversé cette faille, montrent la présence d’une zone endommagée et d’une gouge. Ce travail présente une analyse des lames minces faites à partir de ces carottes. Il confirme la zonation en termes de fracturation à l’approche de la faille. Loin de cette dernière, la fracturation héritée de la phase compressive de l’orogenèse hellénique est dominante, bien qu’il existe aussi une famille E-W liée à l’extension actuelle. Toutes ces fractures sont scellées et le remplissage est similaire d’un point de vue luminescence au calcaire hôte. A l’approche du coeur, la quantité de fractures liées à la faille augmente; le remplissage de ces fractures indique, en cathodoluminescence, le passage de plusieurs fluides qui seraient d’origine externe, et la dernière génération de fractures est encore ouverte. Au mur de la faille, sous 5 m d’épaisseur verticale de cataclasite et d’ultracataclasite dans les calcaires et radiolarites (coeur de faille) et 13 m d’épaisseur verticale de gouge dans les radiolarites, les observations sont plus limitées, car la présence d’un karst a restreint les possibilités de carottage. Néanmoins, on peut observer que le remplissage des fractures liées à l’extension est différent de ce qui nous a été dévoilé au toit. Ceci suggère que la faille, transversalement imperméable aujourd’hui, l’a toujours été. L’analyse de la succession des ciments met en évidence une perméabilité parallèle à la faille à la faveur d’un système de fractures et fentes jeunes et ouvertes, pendant qu’est discuté le transfert de fluides par rapport aux stades de propagation de la faille.
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Sinclair, Victoria A., Sami Niemelä, and Matti Leskinen. "Structure of a Narrow Cold Front in the Boundary Layer: Observations versus Model Simulation." Monthly Weather Review 140, no. 8 (August 1, 2012): 2497–519. http://dx.doi.org/10.1175/mwr-d-11-00328.1.
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Abstract A narrow and shallow cold front that passed over Finland during the night 30–31 October 2007 is analyzed using model output and observations primarily from the Helsinki Testbed. The aim is to describe the structure of the front, especially within the planetary boundary layer, identify how this structure evolved, and determine the ability of a numerical model to correctly predict this structure. The front was shallow with a small (2.5–3 K) temperature decrease associated with it, which is attributed to the synoptic evolution of the cold front from a frontal wave on a mature, trailing cold front in a region of weak upper-level forcing and where the midtroposphere was strongly stratified. Within the boundary layer, the frontal surface was vertical and the frontal zone was narrow (<8 km). The small cross-front scale was probably a consequence of the weak frontolytical turbulent mixing occurring at night, at high latitudes, combined with strong, localized frontogenetic forcing driven by convergence. The model simulated the mesoscale evolution of the front well, but overestimated the width of the frontal zone. Within the boundary layer, the model adequately predicted the stratification and near-surface temperatures ahead of, and within, the frontal zone, but failed to correctly predict the thermal inversion that developed in the stably stratified postfrontal air mass. This case study highlights the complex structure of fronts both within the nocturnal boundary layer, and in a location far from regions of cyclogenesis, and hence the challenges that both forecasters and operational models face.
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Cooper, G. T. "SEISMIC STRUCTURE AND EXTENSIONAL DEVELOPMENT OF THE EASTERN OTWAY BASIN-TORQUAY EMBAYMENT." APPEA Journal 35, no. 1 (1995): 436. http://dx.doi.org/10.1071/aj94028.
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The Eastern Otway Basin exhibits two near-or-thogonal structural grains, specifically NE-SW and WNW-ESE trending structures dominating the Otway Ranges, Colac Trough and Torquay Embayment. The relative timing of these structures is poorly constrained, but dip analysis data from offshore seismic lines in the Torquay Embayment show that two distinct structural provinces developed during two separate extensional episodes.The Snail Terrace comprises the southern structural province of the Torquay Embayment and is characterised by the WNW-ESE trending basin margin fault and a number of small scale NW-SE trending faults. The Torquay Basin Deep makes up the northern structural province and is characterised by the large scale, cuspate Snail Fault which trends ENE-WSW with a number of smaller NE-SW trending faults present.Dip analysis of basement trends shows a bimodal population in the Torquay Embayment. The Snail Terrace data show extension towards the SSW (193°), but this trend changes abruptly to the NE across a hinge zone. Dip data in the Torquay Basin Deep and regions north of the hinge zone show extension towards the SSE (150°). Overall the data show the dominance of SSE extension with a mean vector of 166°.Seismic data show significant growth of the Crayfish Group on the Snail Terrace and a lesser growth rate in the Torquay Basin Deep. Dip data from the Snail Terrace are therefore inferred to represent the direction of basement rotation during the first phase of continental extension oriented towards the SSW during the Berriasian-Barremian? (146-125 Ma). During this phase the basin margin fault formed as well as NE-SW trending ?transtensional structures in the Otway Ranges and Colac Trough, probably related to Palaeozoic features.Substantial growth along the Snail Fault during the Aptian-Albian? suggests that a second phase of extension affected the area. The Colac Trough, Otway Ranges, Torquay Embayment and Strzelecki Ranges were significantly influenced by this Bassian phase of SSE extension which probably persisted during the Aptian-Albian? (125-97 Ma). This phase of extension had little effect in the western Otway Basin, west of the Sorrel Fault Zone, and was largely concentrated in areas within the northern failed Bass Strait Rift. During the mid-Cretaceous parts of the southern margin were subjected to uplift and erosion. Apatite fission track and vitrinite reflectance analyses show elevated palaeotemperatures associated with uplift east of the Sorell Fault Zone.
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Kalinichenko, V. I. "Verbal realization of „FAILURE” and „НЕВДАЧА” concepts in contemporary American and Ukrainian fiction pieces: perception-cognitive and regulatory aspects." Bulletin of Luhansk Taras Shevchenko National University, no. 4 (335) (2020): 5–17. http://dx.doi.org/10.12958/2227-2844-2020-4(335)-5-17.
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The article describes the features of the perception-cognitive and regulation macrostructure components of the FAILURE and НЕВДАЧА concepts in the epidigmatic plane on the basis of the text pieces selected from modern American and Ukrainian fiction. The analysis of these components of the concepts under consideration is carried out in the framework of the semantic cognitive approach by performing the cognitive interpretation procedure of the text pieces, the results of which have been used for formulating semantic cognitive features that constitute the perception-cognitive and regulation layers of the concept. The specificity of the regulatory aspect of understanding the essence of failure by the bearers of American and Ukrainian linguistic consciousness is clarified due to the semantic cognitive features that structure the regulatory zone of the concept macrostructure and update the strategies of the value and target block of the individual in the context of failure. It has been found that in the epidigmatic plane, in the process of conceptualizing failure by American and Ukrainian speakers, perceptual receptors dominate cognitive-mental thought projections. The visual analyzer is the most effective for the bearers of the American and Ukrainian linguistic consciousness in the context of sensory reflection of the failure category, the sound, taste, smell and tactile receptors are less effective. Cognitive subcomponents of the FAILURE and НЕВДАЧА concepts are structured due to vital and floromorphic metaphorical images; zoomorphic and aeromorphic images for the FAILURE concept as well as religious, aquamorphic and subject images for the НЕВДАЧА concept are considered nationally specific. The regulation zone of the FAILURE concept is significantly larger than the similar НЕВДАЧА concept zone, so for Ukrainian speakers rules and guidelines that help regulate areas covering the conceptual nature of failure are more important in understanding the failed outcome of action than for American ones.
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Chen, Junxian, Jianhai Zhang, and Hongwei Zhao. "Designing a Cruciform Specimen via Topology and Shape Optimisations under Equal Biaxial Tension Using Elastic Simulations." Materials 15, no. 14 (July 18, 2022): 5001. http://dx.doi.org/10.3390/ma15145001.
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Stress uniformity within the gauge zone of a cruciform specimen significantly affects materials’ in-plane biaxial mechanical properties in material testing. The stress uniformity depends on the load transmission of the cruciform specimen from the fixtures to the gauge zone. Previous studies failed to alter the nature of the load transmission of the geometric features using parametric optimisations. To improve stress uniformity in the gauge zone, we optimised the cross-arms to design a centre-reduced cruciform specimen with topology and shape optimisations. The simulations show that the optimised specimen obtains significantly less stress variation and range in the gauge zone than the optimised specimen under different observed areas, directions, and load ratios of von Mises, S11, S22, and S12. In the quantified gauge zone, a more uniform stress distribution could be generated by optimizing specimen geometry, whose value should be estimated indirectly each time through simulations. We found that topology and shape optimisations could markedly improve stress uniformity in the gauge zone, and stress concentration at the cross-arms intersection. We first optimised the cruciform specimen structure by combining topology and shape optimisations, which provided a cost-effective way to improve stress uniformity in the gauge zone and reduce stress concentration at the cross-arms intersection, helping obtain reliable data to perform large strains in the in-plane biaxial tensile test.
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Palmowski, D., K. C. Hill, and N. Hoffman. "STRUCTURE AND HYDROCARBONS IN THE SHIPWRECK TROUGH, OTWAY BASIN: HALF-GRABEN GAS FIELDS ABUTTING A CONTINENTAL TRANSFORM." APPEA Journal 44, no. 1 (2004): 417. http://dx.doi.org/10.1071/aj03016.
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As part of a regional study of the evolution of the Otway Basin, the Investigator 3D seismic survey has been structurally analysed, using 11 extracted 2D sections and 3D interpretations of key horizons. South-southwest directed extension was widespread in the Turonian forming the Shipwreck Trough, coincident with uplift of the Otway Ranges to the northeast. The Turonian extension, at ~1.5 myrs, resulted in planar faults in the northeastern part of the Trough, but large half-graben above south-southwest dipping listric master faults in the southwest, both fault sets soling into an Early Cretaceous shale detachment. The half-graben propagated north from the Mussel-Tarpwaup Hinge-Zone by footwall collapse and accommodated deposition of reservoir rocks for the known hydrocarbon accumulations. The half-graben die out along strike to the east at tip-points against an accommodation zone that developed into a continental transform (the Shipwreck Fault).Santonian breakup in the Great Australian Bight coincided with considerable south-southwesterly extension in the Otway Basin juxtaposed against the failed Bassian rift across the Shipwreck Fault. Extension of ~1.21 km to the west of the Shipwreck Fault contrasts with ~0.42 km on the eastern side accommodated by ~0.79 km left-lateral displacement along the Shipwreck Fault. The Belfast Mudstone was deposited during this time, forming the regional seal for the known hydrocarbon accumulations.Limited slow extension during the Campanian to Early Eocene resulted in a further 0.33 km sinistral slip along the Shipwreck Fault. Late Early Eocene Breakup in the Otway Basin ended the transitional phase, terminating extensional and Shipwreck Fault offset. The breakup caused local uplift and ~1 km erosion of Wangerrip Group sediments. The post breakup phase is characterised by prograding sequences indicating progressive-regressive cycles.The Thylacine and La Bella gas fields occur in large tilted fault-blocks near the Hinge-Zone. These successful large structures lie along a longstanding High probably sourced from south of the Hinge-Zone. Key elements for a successful hydrocarbon play are deposition of the Turonian Waarre Formation sandstone reservoirs at rift onset and of a thick Belfast Mudstone seal during continuous Coniacian-Santonian extension. Footwall collapse north of the Hinge-Zone, bound by the deepwater Otway Basin and the continental transform, controlled the distribution of traps, regional seal and hydrocarbon maturation.
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Sammen, Saad Shauket, Marwah Qaddoori Majeed, and Qutaiba G. Majeed. "Stability Assessment of Zoned Earth Dam under Water Particles Fluidity Effect: Hemren Dam as Case Study." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 79, no. 2 (January 15, 2021): 27–38. http://dx.doi.org/10.37934/arfmts.79.2.2738.
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Recently the numerical modeling using finite element method is take into account as a very effective tool to investigate the desired behavior of structures in geotechnical engineering. Earth dams are a water retention structures that are normally wide constructed around the world due to its significant features. These structures may be failed due to exposure to an earthquake and this will result in disaster. The main objective of this study is to assess the slope stability and the seismic response of an earthen dam. Since the matter of seismic response is still have a considerable lack of information for earth dams as a unique structure. Hemren zoned earth dam that is located in Diyala governorate, northeast of Iraq that considered as an active seismic zone has been considered as case study. Numerical modeling has been done in this study using Geo studio software. Factor of safety was calculated with different water levels in order to evaluate the dam safety with different operation water level. The excited earthquake is Elcentro while three values of peak ground acceleration were used which are 0.2, 0.25 and 0.3 g and the duration time is scaled to 10 seconds. In addition, three key points (at the core, the shell and the foundation) that represent the dam construction material are used to evaluate the dynamic response within the dam body. The results revealed that the factor of safety is increased when the water level is increase, but in the increasing in the magnitude of factor of safety with water depths of (10 and 15) m was more than the other depth. The zone of the dam core shows a negative pore water pressure value. That leads to an increasing in effective stress at the core of the dam.
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Khan, Muhammad Yunas. "Afghanistan a Conflict Zone: Post-Taliban Inter and Intra-State Dynamics." Global Strategic & Securities Studies Review VI, no. I (March 30, 2021): 128–40. http://dx.doi.org/10.31703/gsssr.2021(vi-i).14.
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The paper elucidates the conflict zone ‘Afghanistan’ fundamentally divided in two high land and low land climate. from internal perspective and elaborates the inherent issues and internal dynamics of the state that are tormenting its stability. The unit of analysis is state structure and its changing dynamics due to sudden and abrupt shift of power and change in internal dynamics. The recent takeover of government by the Taliban group and its impact on the external and internal dynamics remains the core enquiry of the instant paper. The exploratory analysis is furthered extrapolated with the empirical findings arrived through qualitative method to infer at findings regarding the question of why the country remained as conflict zone and failed to emerge as stable state and viable sate in comity of nations. The public perception about their socio-economic issues and socio- political issues is measured statistically to draw inferences about recommending policy option to the state machinery and reconciliation process
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Grier, Elizabeth J., Amanda K. Petford-Long, and Roger C. C. Ward. "Determination of hydrogen ordering within the β-RH2+xphase (R= Ho, Y) using electron diffraction techniques." Journal of Applied Crystallography 33, no. 5 (October 1, 2000): 1246–52. http://dx.doi.org/10.1107/s0021889800009523.
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Computer simulations of the electron diffraction patterns along the [\bar{1}10] zone axes of four ordered structures within the β-RH2+xphase, withR= Ho or Y, and 0 ≤x≤ 0.25, have been performed to establish whether or not the hydrogen ordering could be detected using electron diffraction techniques. Ordered structures within otherRH2+x(R= Ce, Tb) systems have been characterized with neutron scattering experiments; however, for HoH(D)2+x, neutron scattering failed to characterize the superstructure, possibly because of the lowxconcentration or lack of long-range order within the crystal. This paper aims to show that electron diffraction could overcome both of these problems. The structures considered were the stoichiometric face-centred cubic (f.c.c.) fluorite structure (x= 0), theD1 structure (x= 0.125), theD1astructure (x= 0.2) and theD022structure (x= 0.25). In the stoichiometric structure, with all hydrogen atoms located on the tetrahedral (t) sites, only the diffraction pattern from the f.c.c. metal lattice was seen; however, for the superstoichiometric structures, with the excess hydrogen atoms ordered on the octahedral (o) sites, extra reflections were visible. All the superstoichiometric structures showed extra reflections at the (001)f.c.c.and (110)f.c.c.type positions, with structureD1 also showing extra peaks at (½ ½ ½)f.c.c.. These reflections are not seen in the simulations at similar hydrogen concentrations with the hydrogen atoms randomly occupying theovacancies.
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Welford, J. Kim, Sonya A. Dehler, and Thomas Funck. "Crustal velocity structure across the Orphan Basin and Orphan Knoll to the continent–ocean transition, offshore Newfoundland, Canada." Geophysical Journal International 221, no. 1 (December 26, 2019): 37–59. http://dx.doi.org/10.1093/gji/ggz575.
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SUMMARY Orphan Basin, a massive deepwater rifted basin off the northeastern coast of Newfoundland, was one of the targets of the 2009 SIGNAL (Seismic Investigations off Greenland, Newfoundland and Labrador) experiment to collect refraction/wide-angle reflection (RWAR) data from the Bonavista Platform, through the Orphan Basin, to the Orphan Knoll, and beyond into oceanic crust. Both the data from an earlier RWAR acquisition and the new data were jointly analysed in order to improve on the earlier velocity model and extend its coverage landward and seaward. The resulting velocity model is characterized by an 8–9-km-thick sedimentary package immediately outboard of the Bonavista Platform, which thins toward the Orphan Knoll and beyond. The shallowest modelled sedimentary layer, interpreted as Paleocene and younger post-rift sediments, does not show significant thickness variations and velocities do not exceed 3.3 km s–1. The second modelled sedimentary layer with laterally variable velocities ranging from 2.3 to 5.3 km s–1, interpreted as Late Cretaceous post-rift sediments, is thickest over an interpreted failed rift. The deepest modelled sedimentary layer consists of laterally variable velocities that do not exceed 5.9 km s–1 and is interpreted as possibly Jurassic to Early Cretaceous syn-rift sediments. The crust beneath the Bonavista Platform is subdivided into an upper (5.4–5.9 km s–1), middle (5.9–6.4 km s–1) and lower crust (6.4–6.9 km s–1). The middle crust is modelled as disappearing beneath the seaward limit of the Bonavista Platform at an interpreted failed rift, only to re-appear 100 km further seaward beneath the central Orphan Basin and extend to the seaward limit of the Orphan Knoll, beyond which the crust can be modelled by just an upper (5.0–6.7 km s–1) and a lower (6.7–7.0 km s–1) crustal layer. Towards land, for the first 450 km of the model, velocities generally follow the globally averaged velocity trend for rifted continental crust, albeit with slightly elevated velocities suggestive of magmatic contributions. At the failed rift, within the continental domain, hyperextended crust is modelled, overlying a limited zone of serpentinized mantle. Seaward of Orphan Knoll, the interpretation for the velocity structure is less definitive but an 80-km-wide continent–ocean transition zone consisting of either transitional embryonic oceanic crust or thinned continental crust overlying serpentinized mantle is proposed. Upper mantle velocities as low as 7.7 km s–1 are modelled beneath the interpreted failed continental rift as well as beneath the continent–ocean transition zone, while the rest of the crustal model is underlain by typical mantle velocities of 8 km s–1. Analysis of extension and thinning factors based on the velocity model reveal that the failed rift experienced hyperextension and should have achieved full crustal embrittlement, consistent with localized mantle serpentinization.
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Jia, Suzie Q., Ron C. K. Wong, and David W. Eaton. "Characterization of damage processes in Montney siltstone under triaxial compression using acoustic emission and diagnostic imaging." Geophysical Journal International 228, no. 3 (November 3, 2021): 2005–17. http://dx.doi.org/10.1093/gji/ggab455.
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SUMMARY Crack nucleation and rock failure processes in a fine-grained siltstone (Montney Formation) under triaxial compression are investigated using combined diagnostic techniques, including ultrasonic-wave measurement, acoustic-emission (AE) monitoring, computed tomography (CT) scanning, and thin-section imaging. The sample displays a weak-to-moderate inherent seismic anisotropy and noticeable stress-induced anisotropy prior to failure. No AE event was detected until the applied axial stress reached 95 per cent of the peak value. The signal-to-noise ratio is relatively low, however, and detectable AE events are more diffuse than those observed in highly brittle rocks. The AE locations correlate with a shear fracture zone imaged by CT scanning. AE moment-tensor analysis reveals that events with larger relative magnitudes are characterized by high volumetric (tensile or compressive) components, and the initiation of the failure zone is dominated by combined shear-tensile (ST) failure. Stress inversion of the AE events with high tensile components is in good agreement with the known applied stress. Microscopic imaging of thin sections from the failed sample shows that the failure zone is an en echelon structure consisting of a major fracture with branching micro and minor cracks. This failure mechanism is consistent with a ST source mechanism and is interpreted to be associated with the fine granular structure and mineral composition of Montney siltstone.
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Narsimhachary, D., S. M. Shariff, Snehanshu Pal, G. Padmanabham, and Anindya Basu. "Influence of Joint Configuration on Mechanical Properties of Laser Weld-Brazed Aluminum to Steel Joint." Materials Science Forum 978 (February 2020): 174–80. http://dx.doi.org/10.4028/www.scientific.net/msf.978.174.
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In the present work, laser weld-brazing experiments were performed to produce aluminum to galvanized steel joints in lap and flange configuration. Tests were carried out using Al-12 % Si eutectic filler wire for joining of AA6082 -T6 with galvanized steel with varying laser power and keeping other parameters (wire feed and laser scan speed) constant. Microstructural characteristics of the laser brazed joints, studied by SEM, revealed cast structure in the brazed zone. Intermetallic formed at the steel interface was non-uniform. From the hardness results, it was noted that the brazed region exhibits lower hardness compared to the base material. The wetting length was improved with increasing filler wire rate, which in turn improved the strength of the brazed joint in both the configuration (lap and flange). At 4 kW laser power, flange configuration sample has failed in AA6082 whereas, in case lap joint, failed in the heat affected zone of AA6082.
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Kitazume, Masaki, Akihiko Takahashi, Kenji Harada, and Naotoshi Shinkawa. "New type sand compaction pile method for densification of liquefiable ground underneath existing structure." Journal of Geo-Engineering Sciences 3, no. 1 (June 8, 2016): 1–13. http://dx.doi.org/10.3233/jgs-150032.
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The 2011 Great East Japan Earthquake caused severe damage to infrastructures due to liquefaction, in which many embankments failed with large settlement and slope failure. Sand Compaction Pile method is one of the typical ground improvement methods to densify the ground by installing compacted sand piles into ground. This method has been often applied to mitigate the liquefaction. However, current SCP method of constructing sand piles in vertical direction is not able to densify ground underneath an existing structure. For applying the method to an existing structure, a new type of SCP method was recently developed where in compacted sand columns can be constructed in any direction. This paper briefly introduces the new type of SCP method and the effectiveness of local densification by numerical analysis. In this manuscript, a series of numerical analyses were conducted to evaluate the effect of shape and location of SCP improved zone on the dynamic response of embankment. This paper describes the numerical analyses as well as the development, machinery and procedure of the technique, and emphasizes the uniqueness and effectiveness of the technique for preventing liquefaction for new and existing structures.
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Anwar, Saqib, Ateekh Ur Rehman, Yusuf Usmani, and Ali M. Al-Samhan. "Influence of Post Weld Heat Treatment on the Grain Size, and Mechanical Properties of the Alloy-800H Rotary Friction Weld Joints." Materials 14, no. 16 (August 4, 2021): 4366. http://dx.doi.org/10.3390/ma14164366.
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This study evaluated the microstructure, grain size, and mechanical properties of the alloy 800H rotary friction welds in as-welded and post-weld heat-treated conditions. The standards for the alloy 800H not only specify the composition and mechanical properties but also the minimum grain sizes. This is because these alloys are mostly used in creep resisting applications. The dynamic recrystallization of the highly strained and plasticized material during friction welding resulted in the fine grain structure (20 ± 2 µm) in the weld zone. However, a small increase in grain size was observed in the heat-affected zone of the weldment with a slight decrease in hardness compared to the base metal. Post-weld solution heat treatment (PWHT) of the friction weld joints increased the grain size (42 ± 4 µm) in the weld zone. Both as-welded and post-weld solution heat-treated friction weld joints failed in the heat-affected zone during the room temperature tensile testing and showed a lower yield strength and ultimate tensile strength than the base metal. A fracture analysis of the failed tensile samples revealed ductile fracture features. However, in high-temperature tensile testing, post-weld solution heat-treated joints exhibited superior elongation and strength compared to the as-welded joints due to the increase in the grain size of the weld metal. It was demonstrated in this study that the minimum grain size requirement of the alloy 800H friction weld joints could be successfully met by PWHT with improved strength and elongation, especially at high temperatures.
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Matsubara, Makoto, Hiroshi Sato, Kenji Uehira, Masashi Mochizuki, and Toshihiko Kanazawa. "Three-Dimensional Seismic Velocity Structure Beneath Japanese Islands and Surroundings Based on NIED Seismic Networks Using both Inland and Offshore Events." Journal of Disaster Research 12, no. 5 (September 27, 2017): 844–57. http://dx.doi.org/10.20965/jdr.2017.p0844.
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Tomographic analysis of the seismic velocity structure beneath oceans has always been difficult because offshore events determined by onshore seismic networks have large uncertainties in depth. In order to use reliable event locations for our computations, we have developed a method to use the hypocentral depths determined by the NIED F-net with moment tensor solutions using long-period (20-50 s) waves from offshore events away from onshore seismic networks. We applied seismic tomographic method to events occurring between the years 2000 and 2015 to generate a tomographic image of the Japanese Islands and the surrounding using travel time data picked by the NIED Hi-net, hypocenteral information for onshore earthquakes from the Hi-net, and hypocenter information for offshore events from the F-net. The seismic velocity structure at depths of 30-50 km beneath the Pacific Ocean off the east coast of northeastern Japan and onshore Japan was clearly imaged using both onshore and offshore event date. The boundary between high and low P-wave velocities (Vp) is clearly seen at the Median Tectonic Line beneath southwestern Japan at depths of 10 and 20 km. We discuss how the high-Vp lower crust and low-Vp upper crust beneath central Japan and towards the Sea of Japan are responsible for the failed rift structures formed during the opening of the Sea of Japan. Due to consequent shortening, the crustal deformation has been concentrated along the failed rift zone. Resolution of shallow structures beneath the ocean is investigated using S-net data, confirming the possibility of imaging depths of 5-20 km. In future studies, application of S-net data will be useful in evaluating whether the failed rift structure, formed during the late Cretaceous to early Tertiary, continues towards the shallow regions beneath the Pacific Ocean.
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Chen, Xu Jun, Mu Xiang Dai, and Zhong Yang. "Analysis on Fatigue Failure Modes of Reinforced Concrete Beams Strengthened with BFRP." Applied Mechanics and Materials 744-746 (March 2015): 1367–70. http://dx.doi.org/10.4028/www.scientific.net/amm.744-746.1367.
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The fatigue failure modes of reinforced concrete beams externally strengthened with basalt fiber reinforced polymer(BFRP) sheets was examined in an experimental and analytical study. One strengthened beam failed due to the debonding and fracture of U-wraps FRP sheet at the anchors,and the others failed the fatigue fracture of the longitudinal tensile reinforcements. Based onCode for Design of strengthening concrete structure, the fatigue failure of RC bending members strengthened with FRP was analysed,and the indicate that with reinforcement ratio of 0.612% and fatigue stress ratio of 0.3, only the fatigue fracture of steel bars occured rather than the crushing of concrete in the compression zone.
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Kida, Shinya, Tetsumori Yamashima, Toshihiko Kubota, Haruhide Ito, and Shinjiro Yamamoto. "A light and electron microscopic and immunohistochemical study of human arachnoid villi." Journal of Neurosurgery 69, no. 3 (September 1988): 429–35. http://dx.doi.org/10.3171/jns.1988.69.3.0429.
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✓ The structure of human arachnoid villi was investigated by light and electron microscopy with the aid of immunohistochemical techniques. The human arachnoid villi examined were basically composed of four portions: a fibrous capsule, an arachnoid cell layer, a cap cell cluster, and a central core. The arachnoid cell layer encompassing the central core was mostly covered by the thin fibrous capsule with an endothelial investment. However, the fibrous capsule was often absent at the apical portion of the villus and a factor VIII-related antigen stain failed to confirm the investment of endothelial cells. Instead, the arachnoid cell layer abutted directly upon the lumen of a lateral lacuna or the sinus. The arachnoid cell layer was thickened in places, forming cap cell clusters; it usually consisted of outer and inner zones. On vimentin staining, the former was slightly positive while the latter was strongly positive. The central core contained a network of arachnoid cells intermingled with connective tissue fibers and was in continuity with the cranial subarachnoid space. Electron microscopy showed that the arachnoid cells contained a larger number of intermediate filaments in the inner zone than the outer zone. Ultrastructural immunohistochemical localization showed that vimentin was localized at the intermediate filaments and desmosomal plaques of the arachnoid cells. The arachnoid cells showed a marked variety in both the cell forms and the number of intermediate filaments or desmosomes, depending on their location.
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Lebourgeois, François. "Le blaireau européen (Meles meles L.). Synthèse des connaissances européennes. Partie 1 : choix de l'habitat, structure et densité spatiale des terriers." Revue forestière française 72, no. 1 (February 28, 2020): 11–32. http://dx.doi.org/10.20870/revforfr.2020.5305.
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Le blaireau européen (Meles meles L.) est largement répandu en Europe et en France. C’est un animal social vivant généralement en groupe ou clan familial dans des terriers. Bien que le blaireau puisse s’installer en zone urbanisée, les mosaïques à base de chênes avec des zones ouvertes (prairies, haies, pâtures extensives) sont les biotopes largement privilégiés. Dans ces contextes, les terriers sont creusés préférentiellement dans les sols meubles en zones moyennement pentues à proximité des lisières mais loin des infrastructures humaines. La surface d’un terrier varie de quelques mètres carrés (< 100 m2) à plusieurs centaines (> 500 m2). Globalement, le nombre d’entrées, la longueur cumulée des tunnels et le nombre de chambres augmentent avec la surface. Pour les petits terriers (< 100 m2 ; dits « secondaires »), le nombre d’entrées est généralement inférieur à 10 (souvent 4 à 6), le nombre de chambres entre 0 et 3 et la longueur cumulée des tunnels inférieure à 70 m. Pour les grands terriers (au moins 200 à 300 m2 ; dits « principaux »), les entrées sont de l’ordre de 10 à 15, le nombre de chambres souvent supérieur à 10 et la longueur cumulée des tunnels de plus de 100 mètres. En Europe, la densité moyenne des terriers est de 1,1 ± 1,9 par km2. Les densités les plus fortes sont observées en Europe de l’Ouest (Irlande, Royaume-Uni, France, Espagne…) avec des valeurs moyennes entre 1,4 et 2,2 terriers par km2. Un déplacement vers l’Est (Europe centrale et de l’Est) se traduit par des densités 10 fois plus faibles souvent de moins d’un terrier par 10 km2.
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Clément, V., J. Bouix, A. Gueye, and R. L. Baker. "Estimation des paramètres génétiques de la résistance au parasitisme gastro-intestinal en élevage villageois de petits ruminants au Sénégal." Revue d’élevage et de médecine vétérinaire des pays tropicaux 52, no. 3-4 (March 1, 1999): 291–303. http://dx.doi.org/10.19182/remvt.9678.
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Un protocole d'étude de la résistance génétique aux strongyloses gastro-intestinales a été mis en place sur des races locales d'ovins et de caprins du Sénégal. Des prélèvements de sang et des coproscopies ont été réalisés pendant deux ans sur des animaux de différents troupeaux de la zone de Louga en climat sahélien et de la zone de Kolda en climat soudano-guinéen. L'identité des pères étant inconnue dans ce contexte d'élevage, les apparentements étudiés étaient essentiellement les relations mère-descendant. Les caractères analysés étaient la coproscopie (trois prélèvements par an) en nombre d'oeufs par gramme de fèces (Opg) et l'hématocrite (deux prélèvements par an). Dans la région de Louga, le nombre d'individus étudiés (des deux espèces) était de 377 la première année et 606 la deuxième année. Dans la zone de Kolda, l'échantillon comprenait 671 animaux la première année, 725 la deuxième année. L'héritabilité et la répétabilité ont été estimées à l'aide d'un modèle « animal », avec comme effets fixés la combinaison village*saison*année, l'âge et le stade de lactation pour les mères, la combinaison village*saison*année, l'âge et le sexe pour les jeunes. La répétabilité moyenne intra-année était de 0,19 pour le caractère nombre d'Opg et 0,27 pour l'hématocrite. Elle était plus faible entre années : 0,12 pour le nombre d'Opg et 0,21 pour l'hématocrite. L'estimation de l'héritabilité a présenté des difficultés, à cause de la structure des données villageoises qui ne permettait pas d'estimer directement l'environnement maternel et les effets troupeaux, respectivement en raison de généalogies insuffisantes et de faibles effectifs par élevage. Les estimations de l'héritabilité variaient entre 0 et 0,33 pour le nombre d'Opg et entre 0 et 0,38 pour l'hématocrite selon l'échantillon analysé et le modèle utilisé. Les corrélations génétiques entre caractères n'ont pas pu être estimées. En revanche, les corrélations phénotypiques ont été estimées entre le nombre d'Opg et l'hématocrite, ainsi qu'entre chacune de ces deux variables et le poids des jeunes. Les contraintes liées à une étude génétique en milieu traditionnel ont été discutées.
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Rajarajan, Chakkaravarthi, Paramasivam Sivaraj, Tushar Sonar, Selvaraj Raja, and Nallusamy Mathiazhagan. "Investigation on microstructural features and tensile shear fracture properties of resistance spot welded advanced high strength dual phase steel sheets in lap joint configuration for automotive frame applications." Journal of the Mechanical Behavior of Materials 31, no. 1 (January 1, 2022): 52–63. http://dx.doi.org/10.1515/jmbm-2022-0006.
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Abstract The main objective of this research paper is to study the microstructural features and mechanical properties of resistance spot welded advanced high-strength steel of dual phase grade in lap joint configuration which is mainly employed in sheet form for fabrication of the automotive structure. Resistance spot welding (RSW) being a solid-state welding (SSW) process is used to overcome the problems in fusion welding of AHSS-DP steel such as heat affected zone (HAZ) softening, solidification cracking and distortion which significantly deteriorates the mechanical properties of AHSS-DP800 steel joints. The straight lap (SL-TSFL) and cross lap tensile shear fracture load (CL-TSFL) of spot joints were evaluated. Optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques were used to characterize the weld nugget. The X-ray diffraction (XRD) results are also presented for phase identification in the weld nugget. The fracture surface of failed TSFL specimens was analyzed using SEM. The lap joints made using RSW disclosed superior SL-TSFL, CL-TSFL, and WNZH of 21.7 kN, 17.65 kN, and 589 HV0.5 The superior joint strength and hardness of the weld nugget zone are correlated to the evolution of lath martensite in the nugget zone.
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Haynes, D., and GP Quinn. "Temporal and spatial variability in community structure of a sandy intertidal beach, Cape Paterson, Victoria, Australia." Marine and Freshwater Research 46, no. 6 (1995): 931. http://dx.doi.org/10.1071/mf9950931.
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The infauna of a sheltered sandy intertidal beach at Cape Paterson, Victoria, was sampled on a three-monthly basis over a two-year period. In total, 116495 individuals comprising 41 species were collected over this time. Common species collected included the dipteran Chaetocoelopa sydneyensis, the coleopteran Sphargeris physodes, the isopods Pseudolana concinna and Actaecia thomsoni, the amphipods Talorchestia cf. novaehollandiae and Exoediceroides maculosus, and the polychaetes Magelona sp. and Scolelepis lamellicincta. There were significant differences in infaunal densities and species richness between the beach heights sampled, with both factors increasing with decreasing beach height over the intertidal zone. In generaI, insects were confined to upper beach heights, polychaetes were confined to lower beach heights, and different crustacean species spanned the entire intertidal beach. Significant temporal differences also existed in infaunal densities and species numbers at most of the beach heights sampled. These temporal differences were related to changes in the densities of common intertidal species. Only four of these common species (S. physodes, C. sydneyensis, T. cf. novaehollandiae and E. maculosus) exhibited any seasonal pattern in this temporal variation in density. Multivariate analysis of infaunal data failed to consistently separate beach heights into the universal zones previously proposed for sandy intertidal habitats. The unpredictable nature of biotic and abiotic influences on sandy intertidal infauna makes it unrealistic to expect to be able to consistently separate faunal assemblages on any given sampling occasion, with the exception of a characteristic fauna with terrestrial affinities that is confined to the upper beach. Any zonation patterns identified as being present on sandy beaches need to be qualified by the time of year in which data were collected.
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Henriette, Lapierre, Angelier Jacques, Cogné Xavier, Grand Thierry, and Mascle Georges. "Tectonique superposée de la zone de faille d’Arakapas (Massif de Troodos, Chypre)." Geodinamica Acta 2, no. 4 (January 1988): 197–206. http://dx.doi.org/10.1080/09853111.1988.11105167.
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Das, Souvik, Goutam Mukhopadhyay, and Sandip Bhattacharyya. "Failure analysis of a 40 ton crane hook at a Hot Strip Mill." MATEC Web of Conferences 165 (2018): 10006. http://dx.doi.org/10.1051/matecconf/201816510006.
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There have been accounts of repeated failure of crane hooks at the coil yard of a Hot Strip Mill which pose a serious threat to safety in the area. More than 4 hooks failed in less than 5 years. The crane hook (rated for 36000 kg) failed from the threaded shank while lifting a load of 18143 kg. The metal in the hook was revealed by chemical analysis to be killed IS: 4367 20C15 steel. The hook rod failed from a step where there was a cross sectional change and the locations were associated with machining and chatter marks. Such cross-sectional changes are the potential sites of stress concentrations leading to crack initiations. Fracture surfaces of broken pieces of hook reveal initiation of beach marks from both sides with granular rough surface at the middle of fracture zone. Beach marks initiated from both sides indicate origin of reverse bending fatigue. Distinct granular rough zone at the middle is due to final brittle fracture. Microstructure of the polished sample revealed numerous inclusions which indicate that the steel was not clean .Such a huge number of inclusions are not desirable as they can act as stress concentration sites and lead to fatigue crack initiation. Etched microstructure of failed hook reveals coarse cast structure having inhomogeneous microstructure with a mixture of ferrite and pearlite (which meant lower fatigue strength). This inhomogeneous coarser cast structure is outcome of lower reduction ratio during rolling followed by improper heat treatment process. The fracture was concluded to have occurred due to stress concentration from the step region due to inferior material (Inclusion and Improper Heat treatment process). Preventive maintenance and condition monitoring procedures should be applied to identify and minimize the risk(s) Establishment of an NDT procedure for regular basis inspection of the structural members (welded joints and hookshaped steel rods during incoming inspection and in-service).
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ENNOUNI, Hassan, Abdelouahab SAHLI, and Mohammed ATER. "Contribution à l'étude des paramètres dendrométriques et à la cartographie des peuplements relictuels d’une espèce septentrionale rare au Maroc : Alnus glutinosa (L.) Gaertn." BOIS & FORETS DES TROPIQUES 349 (September 15, 2021): 25–39. http://dx.doi.org/10.19182/bft2021.349.a36777.
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Alnus glutinosa (L.) Gaertn. (Betulaceae) est une espèce clé dans certaines formations alluviales et riveraines du continent européen. Au Maroc, elle se trouve en limite méridionale de son aire de distribution où elle est représentée par des formations relictes dans les zones refuges où elle a migré pendant les phases glaciaires du Pléistocène. Malgré sa grande valeur patrimoniale, il y a très peu de données sur son aire de répartition et l’état des peuplements. Ce travail a permis de localiser et cartographier les principaux peuplements dans la zone d’occurrence de cette espèce dans le Rif au nord du Maroc. La typologie des peuplements a été réalisée dans douze sites de référence en déterminant leurs principales caractéristiques telles que la nature du régime forestier, la composition, la taille, le recouvrement et la densité. Les caractéristiques dendrométriques ont permis de renseigner la structure et la dynamique des peuplements. Les résultats obtenus constituent un apport important de données quantitatives géoréférencées sur la répartition actuelle et la dynamique des peuplements d’A. glutinosa au Maroc. Étant donné l’état de conservation des peuplements, la dégradation de l’habitat et la faible régénération, cette espèce peut être considérée comme menacée et doit bénéficier de mesures urgentes de protection.
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Cook, Matthew C., Heinrich Körner, D. Sean Riminton, Frances A. Lemckert, Jhagvaral Hasbold, Michelle Amesbury, Philip D. Hodgkin, Jason G. Cyster, Jonathon D. Sedgwick, and Antony Basten. "Generation of Splenic Follicular Structure and B Cell Movement in Tumor Necrosis Factor–deficient Mice." Journal of Experimental Medicine 188, no. 8 (October 19, 1998): 1503–10. http://dx.doi.org/10.1084/jem.188.8.1503.
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Secondary lymphoid tissue organogenesis requires tumor necrosis factor (TNF) and lymphotoxin α (LTα). The role of TNF in B cell positioning and formation of follicular structure was studied by comparing the location of newly produced naive recirculating and antigen-stimulated B cells in TNF−/− and TNF/LTα−/− mice. By creating radiation bone marrow chimeras from wild-type and TNF−/− mice, formation of normal splenic B cell follicles was shown to depend on TNF production by radiation-sensitive cells of hemopoietic origin. Reciprocal adoptive transfers of mature B cells between wild-type and knockout mice indicated that normal follicular tropism of recirculating naive B cells occurs independently of TNF derived from the recipient spleen. Moreover, soluble TNF receptor–IgG fusion protein administered in vivo failed to prevent B cell localization to the follicle or the germinal center reaction. Normal T zone tropism was observed when antigen-stimulated B cells were transferred into TNF−/− recipients, but not into TNF/LTα−/− recipients. This result appeared to account for the defect in isotype switching observed in intact TNF/LTα−/− mice because TNF/LTα−/− B cells, when stimulated in vitro, switched isotypes normally. Thus, TNF is necessary for creating the permissive environment for B cell movement and function, but is not itself responsible for these processes.
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Sobornov, Konstantin. "Resource potential of the Chernyshev Swell (the Timan Pechora Basin) in the context of the structure and petroleum habitat of the salt bearing thrust belts." Georesursy 24, no. 1 (March 30, 2022): 36–50. http://dx.doi.org/10.18599/grs.2022.1.4.
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The salt bearing thrust belts are among the most prolific petroleum provinces in the world, including the fold belts flanking the Persian Gulf Basin, the Tarim Basin, the Terek-Sunzha Zone of the Eastern PreCaucasus etc. They are characterized by peculiar structural styles of deformation, large oil and gas pool sizes, significant flow rates. The Chernyshev Swell is among prospective salt bearing thrust belts. It is located in the Cis-Uralian part of the Timan Pechora Basin. Several exploration wells have been drilled in the area so far failed to deliver the anticipated oil and gas deposits. Post mortem study indicated that the main reason for the past failures was the mismatch between the complexities of the geological settings and the used exploration technologies. Integrated study of the area, conducted by the North Uralian Petroleum Company, using modern technologies, including 3D seismic surveying and magnetotelluric sounding, has enabled a far better understanding of this area’s structure and petroleum habitat. It is shown that high petroleum potential is attributed to the transition zone between the Chernyshev Swell and the Kosyu Rogov Foredeep Basin. This study indicated that the area of the Povarnitsa High is of priority interest for explration. This area provides supplementary opportunities in addition to the commercialization of the petroleum exploration potential. It includes production of rare earth and metals in brine of the evaporate deposits. The subsalt reservoirs of the Chernyshev Swell could be used for the storage of gas and CO2 sequestration. Integrated development of the resource potential of the Povarnitsa High may become a key driver of the economic development of the north-eastern part of the Republic of Komi.
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Strong, Jacob W. D., and Alan P. Dickin. "Three-dimensional visualization of top-down superimposed thrust sheets in the SW Grenville Province, Ontario." Geological Magazine 157, no. 2 (June 19, 2019): 149–59. http://dx.doi.org/10.1017/s0016756819000517.
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AbstractTo properly understand the tectonic history of the Grenville Province it is necessary to have a reliable, scientifically based understanding of the present-day three-dimensional (3D) structure of the orogen. Based on detailed Nd isotope mapping of surface boundaries and Lithoprobe seismic sections, this study provides the first detailed visualization of the 3D structure of the Grenville gneiss belt in Ontario using the SketchUp software package. The 3D visualization supports a model in which thrust geometry was imposed from the top downwards, controlled by the NW boundary of the Central Metasedimentary Belt that originated as a failed back-arc rift zone. The Central Metasedimentary Belt boundary controlled the trajectory of the Allochthon Boundary Thrust, its underlying tectonic duplex and, ultimately, the Grenville Front. This process of superimposed thrusting explains the large-scale change in the trajectory of the Grenville Front north of Georgian Bay that has been called the ‘Big Bend’. To assist in visualizing the 3D model, a fly-through animation is provided in the supplementary material.
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Mustaphi, H., F. Medina, H. Jabour, and C. Hoepffner. "Le bassin du Souss (Zone de Faille du Tizi n'Test, Haut Atlas occidental, Maroc): résultat d'une inversion tectonique contrl̂ée par une faille de détachement profonde." Journal of African Earth Sciences 24, no. 1-2 (January 1997): 153–68. http://dx.doi.org/10.1016/s0899-5362(97)00033-x.
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Guisse, Amadou, and Farokh Niass. "Diversity and structure of the ichthyological population of the Gueumbeul Special Wildlife Reserve (Saint-Louis / Senegal)." International Journal of Biological and Chemical Sciences 14, no. 9 (March 25, 2021): 3129–43. http://dx.doi.org/10.4314/ijbcs.v14i9.13.
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The Gueumbeul Special Wildlife Reserve (RSFG) is a very important eco-geographic area. It is frequented by a variety of predominantly piscivorous birds that come to occupy its waters for reproduction and food needs. The present study aimed to make an inventory of the ichthyofauna of the RSFG in order to make available the database of the different species present in this body of water. The ichthyofauna were sampled monthly from March 2019 to February 2020 with the help of artisanal fishermen. The fish populations were studied using statistical analyzes and population descriptors (species richness, density, biomass and diversity indices). In total 16 species of fish divided into 15 genus and 11 families have been identified, cichlids (4 species), mugilids (3 species) being the most diverse families. The most abundant species in the catches were: Sarotherodon melanotheron and Mugil cephalus. The presence of marine species has been noted. These are Dicentrarchus punctatus, Eucinostomus melanopterus and Lichia amia but catches are very low. The calculated diversity indices showed that the ichthyofauna in the reserve has moderate diversity and a poor distribution of individuals within families. The ecosystem of the Gueumbeul basin shows signs of degradation. This degradation is materialized by an overexploitation of fishery resources by the fishing populations and a decrease in mangroves.
La Réserve Spéciale de la Faune de Gueumbeul (RSFG) est une zone éco-géographique très importante. Elle est fréquentée par une diversité d’oiseaux majoritairement piscivores qui viennent occuper la zone pour des besoins de reproduction et d’alimentation. La présente étude visait à faire l’inventaire de la faune ichtyologique de la RSFG afin de rendre disponible la base de données des différentes espèces présentes dans ce plan d’eau. L’ichtyofaune a été échantillonnée de mars 2019 à février 2020 avec l’aide de pêcheurs artisans. Les peuplements de poissons ont été étudiés au moyen d’analyses statistiques et de descripteurs populationnels (la richesse spécifique, la densité, la biomasse et les indices de diversité). Au total 16 espèces de poisson réparties en 11 familles ont été recensées. Les cichlidés (4 espèces), les mugilidés (3 espèces) étant les familles les plus diverses. Les espèces les plus abondantes dans les captures sont : Sarotherodon melanotheron et Mugil cephalus. La présence d’une très faible quantité de poissons d’espèce marine a été notée, il s’agit de Dicentrarchus punctatus, Eucinostomus melanopterus et Lichia amia. Les indices de diversité calculés ont montré que l’ichtyofaune de la réserve a une diversité modérée et une mauvaise répartition des individus au sein des familles. L’écosystème de la cuvette de Gueumbeul présente des signes de dégradation. Cette dégradation est matérialisée par une surexploitation des ressources halieutiques par les populations de pêcheurs et une diminution de la mangrove.
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Barr, Sandra M., Sonya A. Dehler, and Louis Zsámboki. "Connecting Cape Breton Island and Newfoundland, Canada: Geophysical Modeling of pre-Carboniferous 'Basement' Rocks in the Cabot Strait Area." Geoscience Canada 41, no. 2 (May 7, 2014): 186. http://dx.doi.org/10.12789/geocanj.2014.41.041.
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Magnetic and gravity data from northeastern Cape Breton Island, southwestern Newfoundland, and the intervening Cabot Strait area were compiled and used to generate a series of maps displaying magnetic (filtered total field, first and second derivative) and gravity (Bouguer anomaly onshore, free-air anomaly offshore) information to enhance the anomaly pattern associated with regional geology. With further constraints from previously published seismic reflection interpretations and detailed maps of onshore geology, five two-dimensional subsurface models were generated. Potential field anomalies in the offshore can be correlated with onshore faults, rock units, and pre-Carboniferous terranes. In Newfoundland, the Cabot – Long Range Fault separates Grenvillian basement to the northwest from peri-Gondwanan Port aux Basques subzone basement in the southeast and can be traced to the Wilkie Brook Fault on Cape Breton Island. The Cape Ray Fault/Red Indian Line merges offshore with the Cabot – Long Range Fault so that Notre Dame subzone rocks do not extend across the Cabot Strait area. The Port aux Basques – Exploits subzone boundary crosses the strait but is likely buried by younger rocks onshore in Cape Breton Island. Magnetic halos in the Exploits subzone are probably caused by Silurian – Devonian plutons like those in the Burgeo Intrusive Suite. The Exploits – Bras d’Or terrane boundary is located within the Ingonish magnetic anomaly, which was resolved into four overlapping components representing basement sources intruded into metasedimentary rocks and dioritic and granodioritic plutons of the Bras d’Or terrane. The Bras d’Or terrane can be traced to the Cinq-Cerf block and Grey River areas in southern Newfoundland. The interpretations suggest that Bras d’Or terrane ‘basement’ may underlie all of Exploits subzone, and that the Aspy terrane of Cape Breton Island is part of that subzone. SOMMAIRELes données magnétométriques et gravimétriques du nord-est de l’île du Cap-Breton, dans le sud-ouest de Terre-Neuve, et de la région du détroit de Cabot contigu, ont été compilées et utilisées pour produire une série de cartes affichant les particularités magnétiques (champ total filtré, dérivé première et seconde) et gravimétriques (anomalie de Bouguer de la côte, anomalie à l’air libre extracôtière) pour ajouter à la compréhension des motifs d’anomalie de la géologie régionale. En tenant compte des limitations imposées par les interprétations de données de levés de sismique réflexion déjà publiées et de cartes détaillées de géologie continentale, cinq modèles 2D du sous-sol ont été produits. Des anomalies de champ potentiel en zone extracôtière peuvent être corrélées avec des failles, des unités lithologiques et des terranes pré-carbonifères sur la côte. Sur l’île de Terre-Neuve, la faille de Cabot-Long Range qui sépare le socle grenvillien au nord-ouest de la sous-zone de socle péri-gondwanienne, de Port-aux- Basques au sud-est, peut être reliée à la faille de Wilkie Brook sur l’île du Cap-Breton. La faille du Cap Ray et la linéation de Red Indian se fondent au large avec la faille de Cabot – Long Range, ce qui signifie que les roches de la sous-zone de Notre-Dame ne traversent pas la région du détroit de Cabot. La limite de la sous-zone de Port aux Basques-Exploits traverse le détroit, mais elle est vraisemblablement enfouie sous des roches plus jeunes sur l’île du Cap-Breton. Les halos magnétiques dans la sous-zone Exploits sont probablement causés par des plutons siluro-dévoniens comme c’est le cas de ceux de la séquence intrusive de Burgeo. La limite du terrane Exploits-Bras d’Or est située dans l’anomalie magnétique Ingonish, laquelle s’est révélée être constituée de quatre composantes superposées représentant des sources de socle engoncées dans des roches métasédimentaires, et dans des plutons dioritiques et granodioritiques du terrane de Bras d’Or. On peut suivre le terrane de Bras d’Or jusque dans les régions du bloc de Cinq-Cerf et de Grey River dans le sud de Terre-Neuve. Les interprétations permettent de penser que le « socle » du terrane de Bras d’Or pourrait constituer l’assise rocheuse de la sous-zone Exploits, et que le terrane Aspy de l’île du Cap-Breton ferait partie de cette sous-zone.
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Bationo, Babou André, Alkassoum Maïga, Pascal Compaore, and Antoine Kalinganire. "Dimension socioculturelle du baobab Adansonia digitata L. dans le plateau central du Burkina faso." BOIS & FORETS DES TROPIQUES 306, no. 306(4) (December 1, 2010): 23. http://dx.doi.org/10.19182/bft2010.306.a20428.
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Le baobab, Adansonia digitata L., est classé parmi les cinq espèces ligneuses prioritaires au Burkina Faso dont le paysage agraire montre une distribution irrégulière de cette espèce. Les principaux déterminants socioculturels de cette distribution demeurent cependant peu ou mal connus. Le but de cette étude est de caractériser la structure et les facteurs socioculturels qui déterminent la distribution du baobab dans le Centre-Nord et le Centre-Ouest du Burkina Faso. Les travaux ont été menés à travers des inventaires forestiers, des enquêtes socio-éco-nomiques et des observations de terrain sur les pratiques paysannes. Les résultats montrent qu'à l'intérieur d'un même terroir la structure du baobab varie en fonction du type de champ (case, village, brousse). La structure des diamètres épouse une forme en «L» dans les champs de case, une forme en «j» dans les champs de brousse et irrégulière dans les champs de village. Le baobab est considéré dans toute la zone d'étude comme une espèce maléfique abritant des génies, mais aussi en tant que plante alimentaire et médicinale de premier plan. Contrairement au Centre-Ouest, les produits du baobab sont largement utilisés dans l'alimentation et l'artisanat dans le Centre-Nord, où les populations l'entretiennent dans les champs de case et de village par la pratique de la régénération naturelle assistée. La faible présence du baobab dans le Centre-Ouest est en partie liée aux habitudes, au développement du maraîchage qui favorise la disponibilité de condiments alternatifs et aux perceptions que les populations ont vis-à-vis de cet arbre. (Résumé d'auteur)
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Van Rooyen, Deanne, and Sharon D. Carr. "Deconstructing the Infrastructure: A Complex History of Diachronous Metamorphism and Progressive Deformation during the Late Cretaceous to Eocene in the Thor-Odin–Pinnacles Area of Southeastern British Columbia." Geoscience Canada 43, no. 2 (May 18, 2016): 103. http://dx.doi.org/10.12789/geocanj.2016.43.097.
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The Thor-Odin dome is a basement-cored tectonothermal culmination in southern British Columbia containing high-grade metamorphic rocks that were polydeformed in the Late Cretaceous to Eocene. The rocks south of the Thor-Odin dome that extend ca. 20 km to the Pinnacles culmination and Whatshan batholith comprise a heterogeneous tract of polydeformed medium- to high-grade metamorphic rocks and host the South Fosthall pluton near the base of the structural section. They lie in the footwall of the Columbia River fault (CRF) zone, a moderately east-dipping, ductile-brittle, normal fault that was active after ca. 55 Ma and reactivated periodically up to 30 Ma. This tract of rocks has been interpreted as a mid-crustal zone that was exhumed and cooled during Eocene extension or, alternatively, a mid-crustal channel that was bounded at the top by the CRF and was active during the Late Cretaceous to Eocene. However, the timing of metamorphism, deformation, anatexis in basement rocks, and intrusion of leucogranite plutons reveals that there are four tectonothermal domains within the tract that each experienced metamorphism, deformation and cooling at different times. These rocks record Cretaceous metamorphism and cooling in the upper structural levels and three stages of progressive metamorphism and penetrative deformation that migrated into deeper crustal levels in the Paleocene and Eocene producing a complex structural section that was exhumed in part due to motion on the Columbia River fault zone, and in part due to NE-directed transport over a basement ramp.RÉSUMÉLe dôme de Thor-Odin correspond à une culmination tectonothermique d’un noyau de socle dans le sud de la Colombie-Britannique renfermant des roches métamorphiques de haute intensité polydéformées entre le Crétacé supérieur et l’Éocène. Les roches au sud du dôme de Thor-Odin qui s’étendent sur environ 20 km jusqu’à la culmination des Pinnacles et du batholite de Whatshan sont constituées d’une bande hétérogène de roches polydéformées à faciès métamorphique d’intensité moyenne à élevée qui constitue l’encaissant du pluton de South Fosthall près de la base de la colonne structurale. Elles se trouvent dans l'éponte inférieure de la zone de faille de la rivière Columbia (CRF), une faille normale à pendage modéré vers l’est, ductile-fragile, qui a été active après 55 Ma environ et a été réactivée périodiquement jusqu'à 30 Ma. Cette bande de roches a été interprétée comme une zone de mi-croûte qui a été exhumée et a refroidi durant l’extension éocène ou alors comme un canal mi-crustal qui a été limité au sommet par la CRF, et qui a été actif de la fin du Crétacé jusqu’à l’Éocène. Toutefois, la chronologie du métamorphisme, de la déformation, de l’anatexie dans les roches du socle, et de l'intrusion de plutons de leucogranite, montre qu'il existe quatre domaines tectonothermiques pour chaque bande qui ont subit du métamorphisme, de la déformation et du refroidissement à différents moments. Ces roches exhibent un métamorphisme et un refroidissement crétacé dans les niveaux structuraux supérieurs et trois stades de métamorphisme progressif et de déformation pénétrative qui ont migré dans les niveaux crustaux profonds au Paléocène et à l’Eocène constituant ainsi une colonne structurale complexe qui a été exhumée en partie en raison du mouvement de la zone de faille de Columbia River, et en partie en raison du transport vers le N.-E. sur une rampe de socle.
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Verma, Sumit, Shiguang Guo, Thang Ha, and Kurt J. Marfurt. "Highly aliased ground-roll suppression using a 3D multiwindow Karhunen-Loève filter: Application to a legacy Mississippi Lime survey." GEOPHYSICS 81, no. 1 (January 1, 2016): V79—V88. http://dx.doi.org/10.1190/geo2014-0442.1.
Full textAbstract:
Although modern recording capacity facilitates dense seismic acquisition, many, if not most, legacy 3D land surveys are spatially aliased with respect to ground roll. Irregular topography and weathering zones give rise to ground roll that has piecewise rather than continuous linear moveout (LMO). Dispersion often results in shingled events whose phase velocity cuts across the ground-roll noise cone. We have developed a workflow for the suppression of highly aliased broadband ground roll in which modern [Formula: see text] filters failed. Our workflow began with low-pass filtering and windowing the data, 3D patch by 3D patch. We then applied LMO corrections using an average phase velocity of the ground roll and improved these moveout corrections through the use of local three-shot by three-receiver 3D velocity scans about each sample to account for lateral changes in velocity, thickness, and weathering zone topography. Using a Kuwahara algorithm, we chose the most coherent window within which we applied a structure-oriented Karhunen-Loève filter to model the coherent noise. Finally, we removed the LMO correction and subtracted the modeled ground roll from the original data. We applied our workflow to a legacy data volume consisting of four merged 3D surveys acquired in the 1990s. Application of modern seismic attributes showed improved mapping of faults and flexures. We also validated our workflow using a synthetic gather having the same geometry as our field data.
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Li, Shufeng, Qingning Li, Haotian Jiang, Hao Zhang, and Lizhong Zhang. "Experimental Research on Seismic Performance of a New-Type of R/C Beam-Column Joints with End Plates." Shock and Vibration 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/3823469.
Full textAbstract:
This paper presents a new-type of fabricated beam-column connections with end plates. The joint details are as follows: the concrete beams are connected to column by end plates and six high strength long bolts passing through the core area. In addition, in order to increase the stiffness and shear strength, stirrups are replaced by the steel plate hoop in the core zone. To examine the fail behavior of the fabricated beam-column connection specimens, a quasi-static test is conducted for nine full-scale models to obtain the hysteresis curves, skeleton curves, ductility, energy dissipation capacity, and other seismic indicators. The experimental results show that all specimens failed in bending in a malleable way with a beam plastic hinge and the hysteresis curves are excellently plump for the end plate connections. From the seismic indexes, the fabricated connection specimens exhibit better seismic performance, which can provide reference for the application of prefabricated frame structure in the earthquake area.
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Boldyrev, Roman, and Jörg Morré. "Organizational Structure, Channels and Methods of Propaganda Work of the Soviet Military Administration in Germany, 1945–1949." Vestnik Volgogradskogo gosudarstvennogo universiteta. Serija 4. Istorija. Regionovedenie. Mezhdunarodnye otnoshenija, no. 5 (October 2019): 205–21. http://dx.doi.org/10.15688/jvolsu4.2019.5.15.
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Introduction. The paper deals with the issues of the propaganda system in the Soviet Occupation Zone in Germany (SOZ) between 1945 and 1949. Based on de-classified documents from Russian Archives propaganda organization, channels and methods of propaganda units of the Soviet Military Administration in Germany (SMAG) became a subject to study. The authors emphasize on control means towards German mass media and implementing the Soviet propaganda monopoly in East Germany. Methods and materials. The authors consequently analyze the main channels and methods of positive USSR image broadcasting: radio, press, SMAG propaganda unit lectures, people’s education system, activities of society for Soviet cultural studies, acquaintance trips of German delegations to the USSR, presentations of Soviet exhibitions and films. Analysis and Results. The authors come to a conclusion that the Soviet propaganda in East Germany had a low efficiency. It failed to establish a complete monopoly of Soviet propaganda units in East Germany. The SOZ population could access the propaganda from West Germany and West Berlin, which broadcast a radically negative image of the USSR. Besides, the units and institutions of the Group of Soviet Occupation Troops in Germany (GSOTG) created their own image of Soviet people, which was different from the ideal and broadcast one. Thus, it turned out to be impossible to provide the unification of the broadcast and perception of propagandist materials devoted to the USSR and its population. Soviet propaganda in Germany had gone through the transition by the late 1940s: division of Germany in two states appeared to be a reality, and the establishment of socialist society on Stalin’s model took place in East Germany. Ideological revisiting of the Soviet social constitution, and so its supremacy over the bourgeois one was to replace the conventional image of the country of total welfare and happiness.
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Sun, Haitao, Linchao Dai, Yanbao Liu, and Hongwei Jin. "Critical Conditions and Energy Transfer Characteristics of the Failure Process of Coal-Rock Combination Systems in Deep Mines." Geofluids 2021 (February 24, 2021): 1–14. http://dx.doi.org/10.1155/2021/6655443.
Full textAbstract:
With the steady increase in the size, intensification, and modernization of coal production enterprises, the deep coal resources in large coal bases are gradually entering the mining stage. When the coal mining reaches the deep zone, the interactions between various underground dynamic hazards begin to occur. These interactions are affected by the engineering geological environment and can lead to the occurrence of severe compound hazards. When coal and gas outbursts occur and destabilize the mining area, the high geostress causes the multiphysical coupling effect of the laminated overburden system to become more pronounced. Therefore, we analyzed the development path of a coal-rock system under instability conditions from the perspective of coal–rock coupling, constructed a model of the coal-rock combination system’s structure, and proposed three directions (i.e., strain softening, limit equilibrium, and dynamic instability) for the development of coal-rock system instability. Then, we established a model for the critical conditions of the system’s failure process and elucidated that the release of the rock’s elastic energy promoted the instability of the coal. Furthermore, we verified the established critical conditions through laboratory tests on a coal-rock combination structure and obtained the patterns of the rock energy transferring into the coal seam during the instability failure process of the coal–rock combination structure. When the coal–rock combination structure failed, the rock strain reached its maximum value and the strain rebound phenomenon occurred. The stored elastic strain energy released by the rock into the combination system accounted for 26% to 53% of the accumulated energy in the rock itself, and the released elastic energy and the new surface area of the crushed coal sample followed a logarithmic relationship. The findings of this study provide theoretical support for the identification and quantitative analysis of instability due to the dynamic hazards of coal-rock gas in deep mines.
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Tanner, Lee E., Loren Jacobson, and Ron Gronsky. "Rapidly Solidified Microstructures in Eutectic Alloys." Proceedings, annual meeting, Electron Microscopy Society of America 43 (August 1985): 50–51. http://dx.doi.org/10.1017/s0424820100117327.
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A primary goal of RSP has been to enhance the post-solidification age-hardening behavior of alloys via the extension of solute solubility of their terminal solid solutions. In the case of Al-Be, it was a matter of creating supersaturation of Be in Al since Be solubility is so very low at equilibrium. This approach failed and melt-quenching produced a variety of fine-scale, two-phase microstructures in splats and ribbons. Included were remarkably uniform dispersions of tiny, spherical, incoherent Be particles appearing over a range of compositions spanning the eutectic (Ce=2.5 at% Be) and beyond. The dispersions can be found in hypoeutectic alloys but are restricted to the chill zone in contact with the cold substrate. Fig. 1a,b shows 3-5nm Be particles clustered within the central region of a grain in Al-0.5 at% Be. Further into the bulk of a splat or ribbon the grains have the expected cellular structure of primary Al enclosed by cell walls filled with the small Be particles (Fig. 1c,d).