Journal articles on the topic 'Compaction band'
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Rudnicki, J. W. "Models for compaction band propagation." Geological Society, London, Special Publications 284, no. 1 (2007): 107–25. http://dx.doi.org/10.1144/sp284.8.
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Stefanou, Ioannis, and Jean Sulem. "Chemically induced compaction bands: Triggering conditions and band thickness." Journal of Geophysical Research: Solid Earth 119, no. 2 (February 2014): 880–99. http://dx.doi.org/10.1002/2013jb010342.
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Heap, Michael J., Nicolas Brantut, Patrick Baud, and Philip G. Meredith. "Time-dependent compaction band formation in sandstone." Journal of Geophysical Research: Solid Earth 120, no. 7 (July 2015): 4808–30. http://dx.doi.org/10.1002/2015jb012022.
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Czech, Krzysztof R., and Wojciech Gosk. "Impact of the Operation of a Tri-band Hydraulic Compactor on the Technical Condition of a Residential Building." Applied Sciences 9, no. 2 (January 18, 2019): 336. http://dx.doi.org/10.3390/app9020336.
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The study investigates the surface vibrations generated by a new generation, tri-band hydraulic compactor type V8 from Maschinentechnik Schrode AG (MTS), and a reversible plate compactor type DPU 6055 from Wacker Neuson in close proximity to a low-rise residential building. Compaction works were carried out in three stages, at distances: 15 m, 10 m, and 5 m from the building, and at three depths: 0.4 m, 1.2 m, and 1.8–2.0 m. The research was conducted at one measurement point, located on the outer foundation wall of the building, and at three measurement points located on the ground at distances of 1.25–7.5 m from the building. The study analyses the distribution of peak component particle accelerations at the ground, and peak component particle velocities at the foundation wall of the building as a function of the distance of compactors from the building and the depth of compaction works, as well as the mode of work of hydraulic compactor type V8 from MTS. The study contains the comparison of the permissible vibration levels that are recommended by selected European standards (DIN, BS, VSS, and PL) and an approximate assessment of the impact of vibrations on the technical condition of the residential building.
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Keehm, Youngseuk, Kurt Sternjof, and Tapan Mukerji. "Computational estimation of compaction band permeability in sandstone." Geosciences Journal 10, no. 4 (December 2006): 499–505. http://dx.doi.org/10.1007/bf02910443.
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Redanz, Pia, and Viggo Tvergaard. "Analysis of shear band instabilities in compaction of powders." International Journal of Solids and Structures 40, no. 8 (April 2003): 1853–64. http://dx.doi.org/10.1016/s0020-7683(03)00034-9.
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Robert, Romain, Pauline Souloumiac, Philippe Robion, and Christian David. "Numerical Simulation of Deformation Band Occurrence and the Associated Stress Field during the Growth of a Fault-Propagation Fold." Geosciences 9, no. 6 (June 9, 2019): 257. http://dx.doi.org/10.3390/geosciences9060257.
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Knowledge of the paleo-stress distribution is crucial to understand the fracture set up and orientations during the tectonic evolution of a basin, and thus the corresponding fluid flow patterns in a reservoir. This study aims to predict the main stress orientations and evolution during the growth of a fold by using the limit analysis method. Fourteen different steps have been integrated as 2D cross sections from an early stage to an evolved stage of a schematic and balanced propagation fold. The stress evolution was followed during the time and burial of syn tectonic layers localized in front of the thrust. Numerical simulations were used to predict the occurrence and orientation of deformation bands, i.e., compaction and shear bands, by following the kinematic of a fault-propagation fold. The case study of the Sant-Corneli-Boixols anticline was selected, located in the South Central Pyrenees in the Tremp basin, to constrain the dimension of the starting models (or prototypes) used in our numerical simulations. The predictions of the numerical simulations were compared to field observations of an early occurrence of both pure compaction- and shear-enhanced compaction bands in the syn-tectonic Aren formation located in front of the fold, which are subjected to early layer parallel shortening during the burial history. Stress magnitude and stress ratio variations define the type of deformation band produced. Our results show that the band occurrence depends on the yield envelope of the host material and that a small yield envelope is required for these shallow depths, which can only be explained by the heterogeneity of the host rock facies. In our case, the heterogeneity can be explained by a significant contribution of carbonate bioclasts in the calcarenite rock, which change the mechanical behavior of the whole rock.
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Cecinato, Francesco, and Alessandro Gajo. "Dynamical effects during compaction band formation affecting their spatial periodicity." Journal of Geophysical Research: Solid Earth 119, no. 10 (October 2014): 7487–502. http://dx.doi.org/10.1002/2014jb011060.
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Esin, Maxim, Arcady V. Dyskin, and Elena Pasternak. "Large-Scale Deformation Patterning in Geomaterials Associated with Grain Rotation." Advanced Materials Research 891-892 (March 2014): 872–77. http://dx.doi.org/10.4028/www.scientific.net/amr.891-892.872.
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Modelling of large-scale deformation patterning in geomaterials is important for predicting instabilities and failures in the Earths crust. Shear band formation and the evolution of the bands is a predominant mechanism of deformation patterning. Independent rotations of separate grains/particles can affect the pattern formation by adding the effect of rotational degrees of freedom to the mechanism of instability. To model this mechanism we use a special experimental technique based on digital image correlation in order to recover both displacement and independent rotation fields in 2D physical models of granular material. In the physical model the particles are represented by smooth steel monodispersed disks with speckles painted on them to enable the rotation reconstruction. During the loading the deformation pattern undergoes stages of shear band formation followed by its dissolution due to re-compaction and particle rearrangement with the subsequent formation of multiple shear bands merging into a single one and the final dissolution. Also, patterns of rotations are observed at an intermediate scale between the scale of the particles and the scale of the shear band.
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Chemenda, A. I. "The formation of tabular compaction-band arrays: Theoretical and numerical analysis." Journal of the Mechanics and Physics of Solids 57, no. 5 (May 2009): 851–68. http://dx.doi.org/10.1016/j.jmps.2009.01.007.
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Kibitkin, Vladimir, Mikhail Grigoriev, Alexander Burlachenko, Andrey Solodushkin, Nickolai Savchenko, Valery Rubtsov, and Sergei Tarasov. "In Situ Investigation of Strain Localization in Sintered, Porous Segmented Alumina." Materials 14, no. 13 (July 2, 2021): 3720. http://dx.doi.org/10.3390/ma14133720.
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Evaporation of paraffin and ultra-high-molecular-weight polyethylene admixed with alumina powder for the slip casting and sintering process allowed the obtainment of segmented porous alumina ceramics with 50% total porosity, whose deformation behavior we studied. Structurally, these ceramic materials were composed of large and small pores, and a system of discontinuities subdividing the samples into segments. Using digital image correlation (DIC), strain distribution maps were obtained that allowed the observation of strain localization zones, where primary cracks propagated along the interblock discontinuities. Two stages were revealed to be responsible for different mechanisms that provided the sample with damage tolerance under compression loading: the first stage was crack propagation along the block boundaries, which was followed by the second stage of microcracking and fragmentation, consisting of filling of the free spaces with fragments, compaction band generation, and stabilization of the crack. Both stages comprise a cycle that is repeated again and again until the full volume of the sample is occupied by the compaction bands.
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Fossen, Haakon, Richard A. Schultz, and Anita Torabi. "Conditions and implications for compaction band formation in the Navajo Sandstone, Utah." Journal of Structural Geology 33, no. 10 (October 2011): 1477–90. http://dx.doi.org/10.1016/j.jsg.2011.08.001.
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Kawanishi, J., J. Kato, K. Sasaki, S. Fujii, N. Watanabe, and Y. Niitsu. "Loss of E-cadherin-dependent cell-cell adhesion due to mutation of the beta-catenin gene in a human cancer cell line, HSC-39." Molecular and Cellular Biology 15, no. 3 (March 1995): 1175–81. http://dx.doi.org/10.1128/mcb.15.3.1175.
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Detachment of cell-cell adhesion is indispensable for the first step of invasion and metastasis of cancer. This mechanism is frequently associated with the impairment of either E-cadherin expression or function. However, mechanisms of such abnormalities have not been fully elucidated. In this study, we demonstrated that the function of E-cadherin was completely abolished in the human gastric cancer cell line HSC-39, despite the high expression of E-cadherin, because of mutations in one of the E-cadherin-associated cytoplasmic proteins, beta-catenin. Although immunofluorescence staining of HSC-39 cells by using an anti-E-cadherin antibody (HECD-1) revealed the strong and uniform expression of E-cadherin on the cell surface, cell compaction and cell aggregation were not observed in this cell. Western blotting (immunoblotting) using HECD-1 exhibited a 120-kDa band which is equivalent to normal E-cadherin. Northern (RNA) blotting demonstrated a 4.7-kb band, the same as mature E-cadherin mRNA. Immunoprecipitation of metabolically labeled proteins with HECD-1 revealed three bands corresponding to E-cadherin, alpha-catenin, and gamma-catenin and a 79-kDa band which was apparently smaller than that of normal beta-catenin, indicating truncated beta-catenin. The 79-kDa band was immunologically identified as beta-catenin by using immunoblotting with anti-beta-catenin antibodies. Examination of beta-catenin mRNA by the reverse transcriptase-PCR method revealed a transcript which was shorter than that of normal beta-catenin. The sequencing of PCR product for beta-catenin confirmed deletion in 321 bases from nucleotides +82 to +402. Southern blotting of beta-catenin DNA disclosed mutation at the genomic level. Expression vectors of Beta-catenin were introduced into HSC-39 cells by transfection. In the obtained transfectants, E-cadherin-dependent cell-cell adhesiveness was recovered, as revealed by cell compaction, cell aggregation, and immunoflourescence staining. From these results, it was concluded that in HSC-39 cells, impaired cell-cell adhesion is due to mutations in beta-catenin which results in the dysfunction of E-cadherin.
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Jakubas, Adam, Radosław Jastrzębski, and Krzysztof Chwastek. "Modelling the effect of compaction pressure on hysteresis curves of self-developed SMC cores." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 38, no. 4 (July 1, 2019): 1154–63. http://dx.doi.org/10.1108/compel-10-2018-0399.
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Purpose The purpose of this paper is to examine the effect of varying compaction pressure on magnetic properties of self-developed soft magnetic composite (SMC) cores. The change in shape of ferromagnetic hysteresis curves has – in turn – the impact on the values of hysteresis model parameters. The phenomenological GRUCAD model is chosen for description of hysteresis curves. Design/methodology/approach Several cylinder-shaped cores have been made from a mixture of iron powder and suspense polyvinyl chloride using a hydraulic press with a form and a band with a thermocouple for controlling heat treatment conditions. The only varying parameter in the study is the compaction pressure. The magnetic properties of developed cores have been measured using a computer-acquisition card and LabView software. The obtained hysteresis curves are fitted to the equations of the phenomenological GRUCAD model. This description is compliant with the laws of irreversible thermodynamics. The variations of model parameters are presented as functions of compacting pressure. Findings The compaction pressure has a significant impact on magnetic properties of self-developed SMC cores. The paper provides a number of charts useful for checking how the parameters of the hysteresis model are affected. Research limitations/implications The present paper is limited to modelling symmetrical loops only. Description of more complex magnetization cycles is postponed to another, forthcoming paper. Practical implications The GRUCAD hysteresis model may be a useful tool for the designers of magnetic circuits. Its parameters depend on the processing conditions (in this study – the compaction pressure) of the SMC cores. Originality/value Modelling of magnetic properties of SMC cores has been carried so far using some well-known description like Preisach, Takács and Jiles–Atherton proposals. The GRUCAD model has a number of advantages, and it may be a useful alternative to the latter formalism. So far it has been used for description of hysteresis curves in conventional materials like non-oriented and grain-oriented electrical steels. In the present work, it is applied to novel SMC materials.
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Schultz, Richard A., Chris H. Okubo, and Haakon Fossen. "Porosity and grain size controls on compaction band formation in Jurassic Navajo Sandstone." Geophysical Research Letters 37, no. 22 (November 2010): n/a. http://dx.doi.org/10.1029/2010gl044909.
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Kozlova, T. u., V. F. Semeshin, I. V. Tretyakova, E. B. Kokoza, V. Pirrotta, V. E. Grafodatskaya, E. S. Belyaeva, and I. F. Zhimulev. "Molecular and cytogenetical characterization of the 10A1-2 band and adjoining region in the Drosophila melanogaster polytene X chromosome." Genetics 136, no. 3 (March 1, 1994): 1063–73. http://dx.doi.org/10.1093/genetics/136.3.1063.
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Abstract Some 300 kb of DNA from the 9F12-10A7 X chromosome region (seven bands) uncovered by Df(1)vL3 were cloned and 31 break points of chromosome rearrangements within the region were mapped. Positions of 12 genes found earlier in genetic saturation experiments, transcripts and P element-induced mutations were located on the physical map using either chromosome rearrangements or Southern blot hybridizations. Data on the position of the break points, genes and polytene chromosome bands allow the following conclusions to be made. (1) The size of the bands in the region varies between 4 kb (10A6 and 7) and 183-195 kb (10A1-2). The compaction ratio of DNA in bands varies from 8-36 (10A6 + 7) to 151-161 (10A1-2). Therefore, fine and thick bands appear to have different kinds of DNP packaging. (2) The bands differ in genetic content. Fine bands contain from one to three genes. In contrast, the 10A1-2 band contains three genes and at least six transcribed DNA fragments. (3) Comparison of genetic and physical maps shows that in this region 0.01 centiMorgan corresponds to 3.3 kb of DNA.
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Challa, Vennela, and Kathleen A. Issen. "Conditions for Compaction Band Formation in Porous Rock Using a Two-Yield Surface Model." Journal of Engineering Mechanics 130, no. 9 (September 2004): 1089–97. http://dx.doi.org/10.1061/(asce)0733-9399(2004)130:9(1089).
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Sun, WaiChing, and Jose E. Andrade. "Capturing the effective permeability of field compaction band using hybrid lattice Boltzmann/Finite element simulations." IOP Conference Series: Materials Science and Engineering 10 (June 1, 2010): 012077. http://dx.doi.org/10.1088/1757-899x/10/1/012077.
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Charalampidou, Elli-Maria, Stephen A. Hall, Sergei Stanchits, Gioacchino Viggiani, and Helen Lewis. "Shear-enhanced compaction band identification at the laboratory scale using acoustic and full-field methods." International Journal of Rock Mechanics and Mining Sciences 67 (April 2014): 240–52. http://dx.doi.org/10.1016/j.ijrmms.2013.05.006.
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Xiao, Zeng Li, Yong Jie Fan, and Jun Bin Chen. "Mechanism and Application Effect of Compound Perforation Fracturing Technology in Low Permeability Reservoir." Applied Mechanics and Materials 675-677 (October 2014): 1500–1504. http://dx.doi.org/10.4028/www.scientific.net/amm.675-677.1500.
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Compound perforation fracturing technology is a space combination type ultra-deep perforating that can overcome some flaws conventional perforation has, such as shallow penetration and compaction damage. It can remove the compaction band and near wellbore pollution in rock matrix which results from conventional perforation. This paper introduces the theory of effect and influence factor of compound perforation fracturing technology and summarize the advantages for low permeability gas well on the basis of analyzing the mechanism of action about increase production of compound perforation. In order to evaluate the effects of application of this technology in in low permeability reservoir, 11 compound perforation wells and 12 conventional perforation wells were selected which have the similar physical property and the evaluation was conducted in two blocks. The results show that compound perforation can make the formation fracture pressure decrease in 3~5MPa and increase the permeability near the perforation channel. This technology has better effects than the conventional and decrease the cost effectively, improving production in low permeability oil and gas field.
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Sadeghi-Chahardeh, Alireza, Roozbeh Mollaabbasi, Donald Picard, Seyed Mohammad Taghavi, and Houshang Alamdari. "Effect of Particle Size Distributions and Shapes on the Failure Behavior of Dry Coke Aggregates." Materials 14, no. 19 (September 24, 2021): 5558. http://dx.doi.org/10.3390/ma14195558.
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Carbon anodes participate in chemical reactions to reduce alumina in the Hall–Héroult process, of which coke aggregates make up a major part. The failure analysis of coke aggregates not only leads to a better understanding of the deformation mechanisms of anode paste under compressive loading but also can identify potential causes of structural defects in carbon anodes, such as horizontal cracks. The coke aggregates are composed of particles with different size distributions and shapes, which may strongly affect the failure behavior of the anode during compaction. In this paper, the effects of particle size distributions and shapes on the mechanical behavior and the failure of coke aggregates are investigated using the discrete element method modeling technique. The numerical results reveal that, although the mechanical behavior of coke mixtures is generally dependent on larger particles, the presence of fine particles in the coke aggregates reduces fluctuations in the stress–strain diagram. In addition, the rolling resistance model is employed as a parameter representing the effect of particle shape. It is shown that the rolling resistance model can be an alternative to the overlapped spheres model, which has a higher computational cost than the rolling resistance model. The second-order work criterion is used to evaluate the stability of the coke aggregates, the results of which indicate that the addition of fine particles as well as increasing the rolling resistance between the particles increases the stability range of the coke aggregates. Moreover, by using the analysis of micro-strain contour evaluations during the compaction process, it is shown that, both by adding fine particles to the coke mixture and by increasing the rolling resistance between the particles, the possibility of creating a compression band in the coke aggregates is reduced. Since the presence of the compaction bands in the anode paste creates an area prone to horizontal crack generations, the results of this study could lead to the production of carbon anodes with fewer structural defects.
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Xiong, Bao Lin, and Chun Jiao Lu. "Size Effect on the Deformation Characteristic and Shear Band of Granular Material Based on Hypoplastity." Applied Mechanics and Materials 584-586 (July 2014): 1789–93. http://dx.doi.org/10.4028/www.scientific.net/amm.584-586.1789.
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The deformation characteristic of granular material is important. It is important factor to analysis the bearing capacity and the thickness of granular material footings. There are many factors influence the deformation of granular material, such as material characteristic, content of water, degree of compaction, test method, etc. For analyzing size effect on the deformation characteristic of granular material, hypoplastic constitutive model considering void ratio is introduced. The influence of an initial void ratio, pressure and a mean grain diameter on the deformation is investigated by polar quantities: rotations, curvatures, couple stresses and a characteristic length. Thus, the influence of density and pressure on the initiation of shear bands can be investigated with a single set of constitutive constants.
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Sidorenko, D. S., T. Yu Zykova, V. A. Khoroshko, G. V. Pokholkova, S. A. Demakov, J. Larsson, E. S. Belyaeva, and I. F. Zhimulev. "Polytene chromosomes reflect functional organization of the Drosophila genome." Vavilov Journal of Genetics and Breeding 23, no. 2 (March 30, 2019): 148–53. http://dx.doi.org/10.18699/vj19.474.
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Polytene chromosomes of Drosophila melanogaster are a convenient model for studying interphase chromosomes of eukaryotes. They are giant in size in comparison with diploid cell chromosomes and have a pattern of cross stripes resulting from the ordered chromatid arrangement. Each region of polytene chromosomes has a unique banding pattern. Using the model of four chromatin types that reveals domains of varying compaction degrees, we were able to correlate the physical and cytological maps of some polytene chromosome regions and to show the main properties of genetic and molecular organization of bands and interbands, that we describe in this review. On the molecular map of the genome, the interbands correspond to decompacted aquamarine chromatin and 5’ ends of ubiquitously active genes. Gray bands contain lazurite and malachite chromatin, intermediate in the level of compaction, and, mainly, coding parts of genes. Dense black transcriptionally inactive bands are enriched in ruby chromatin. Localization of several dozens of interbands on the genome molecular map allowed us to study in detail their architecture according to the data of whole genome projects. The distribution of proteins and regulatory elements of the genome in the promoter regions of genes localized in the interbands shows that these parts of interbands are probably responsible for the formation of open chromatin that is visualized in polytene chromosomes as interbands. Thus, the permanent genetic activity of interbands and gray bands and the inactivity of genes in black bands are the basis of the universal banding pattern in the chromosomes of all Drosophila tissues. The smallest fourth chromosome of Drosophila with an atypical protein composition of chromatin is a special case. Using the model of four chromatin states and fluorescent in situ hybridization, its cytological map was refined and the genomic coordinates of all bands and interbands were determined. It was shown that, in spite of the peculiarities of this chromosome, its band organization in general corresponds to the rest of the genome. Extremely long genes of different Drosophila chromosomes do not fit the common scheme, since they can occupy a series of alternating bands and interbands (up to nine chromosomal structures) formed by parts of these genes.
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Pizzati, Mattia, Fabrizio Balsamo, Fabrizio Storti, and Paola Iacumin. "Physical and chemical strain-hardening during faulting in poorly lithified sandstone: The role of kinematic stress field and selective cementation." GSA Bulletin 132, no. 5-6 (October 25, 2019): 1183–200. http://dx.doi.org/10.1130/b35296.1.
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Abstract In this work, we report the results of a multidisciplinary study describing the structural architecture and diagenetic evolution of the Rocca di Neto extensional fault zone developed in poorly lithified sandstones of the Crotone Basin, Southern Italy. The studied fault zone has an estimated displacement of ∼90 m and consists of: (1) a low-deformation zone with subsidiary faults and widely spaced deformation bands; (2) an ∼10-m-wide damage zone, characterized by a dense network of conjugate deformation bands; (3) an ∼3-m-wide mixed zone produced by tectonic mixing of sediments with different grain size; (4) an ∼1-m-wide fault core with bedding transposed into foliation and ultra-comminute black gouge layers. Microstructural investigations indicate that particulate flow was the dominant early-stage deformation mechanism, while cataclasis became predominant after porosity loss, shallow burial, and selective calcite cementation. The combination of tectonic compaction and preferential cementation led to a strain-hardening behavior inducing the formation of “inclined conjugate deformation band sets” inside the damage zone, caused by the kinematic stress field associated with fault activity. Conversely, conjugate deformation band sets with a vertical bisector formed outside the damage zone in response to the regional extensional stress field. Stable isotope analysis helped in constraining the diagenetic environment of deformation, which is characterized by mixed marine-meteoric signature for cements hosted inside the damage zone, while it progressively becomes more meteoric moving outside the fault zone. This evidence supports the outward propagation of fault-related deformation structures in the footwall damage zone.
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Hess, M., C. Wöhler, M. Bhatt, A. A. Berezhnoy, A. Grumpe, K. Wohlfarth, A. Bhardwaj, and V. V. Shevchenko. "Processes governing the VIS/NIR spectral reflectance behavior of lunar swirls." Astronomy & Astrophysics 639 (July 2020): A12. http://dx.doi.org/10.1051/0004-6361/201937299.
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We investigated six bright swirls associated with magnetic anomalies of variable strength using Chandrayaan-1 Moon Mineralogy Mapper (M3) hyperspectral image data. We examined the 3 μm absorption band generally ascribed to solar wind-induced OH/H2O and spectral trends in the near-infrared wavelength range at on-swirl and off-swirl locations. We found that the 3 μm absorption band is weaker at on-swirl than at off-swirl locations and shows only weak variations with time-of-day. This result is consistent with magnetic anomaly shielding that reduces solar wind interaction with the surface. For a small swirl structure in Mare Moscoviense, we found the 3 μm absorption band to be similar to that of its surroundings due to the absence of strong magnetic shielding. Our spectral analysis results at on-swirl and off-swirl locations suggest that the spectral trends at on-swirl and off-swirl locations cannot always be explained by reduced space-weathering alone. We propose that a combination of soil compaction possibly resulting from the interaction between the surface and cometary gas and subsequent magnetic shielding is able to explain all observed on-swirl vs. off-swirl spectral trends including the absorption band depth near 3 μm. Our results suggest that an external mechanism of interaction between a comet and the uppermost regolith layer might play a significant role in lunar swirl formation.
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Jiang, Yiwei, Robert N. Carrow, and Ronny R. Duncan. "Correlation Analysis Procedures for Canopy Spectral Reflectance Data of Seashore Paspalum under Traffic Stress." Journal of the American Society for Horticultural Science 128, no. 3 (May 2003): 343–48. http://dx.doi.org/10.21273/jashs.128.3.0343.
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Traffic stresses often cause a decline in turfgrass quality. Analysis of spectral reflectance is valuable for assessing turfgrass canopy status. The objectives of this study were to determine correlations of narrow band canopy reflectance and selected reflectance indices with canopy temperature and turf quality for seashore paspalum exposed to wear and wear plus soil compaction traffic stresses, and to evaluate the effects of the first derivative of reflectance and degree of data smoothing (spectral manipulations) on such correlations. `Sea Isle 1' seashore paspalum (Paspalum vaginatum Swartz) was established on a simulated sports field during 1999 and used for this study. Compared to original reflectance, the first derivative of reflectance increased the correlation coefficient (r) of certain wavelengths with canopy temperature and turf quality under both traffic stresses. Among 217 wavelengths tested between 400 and 1100 nm, the peak correlations of the first derivative of reflectance occurred at 661 nm and 664 nm for both canopy temperature and turf quality under wear stress, respectively, while the highest correlations were found at 667 nm and 820 to 869 nm for both variables under wear plus soil compaction. Collectively, the first derivative of reflectance at 667 nm was the optimum position to determine correlation with canopy temperature (r > 0.62) and turf quality (r < -0.72) under both traffic stresses. All correlations were not sensitive to degrees of smoothing of reflectance from 400 to 1100 nm. A ratio of R936/R661 (IR/R, Infrared/red) and R693/759 (stress index) had the strongest correlations with canopy temperature for wear (r = -0.63) and wear plus soil compaction (r = 0.66), respectively; and a ratio of R693/R759 had the strongest correlation with turf quality for both wear (r = -0.89) and wear plus soil compaction (r = -0.82). The results suggested that the first derivative of reflectance could be used to estimate any single wavelength simultaneously correlated with multiple turf canopy variables such as turf quality and canopy temperature, and that the stress index (R693/R759) was also a good indicator of canopy stress status.
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Jiang, Yiwei, Robert N. Carrow, and Ronny R. Duncan. "Effects of Morning and Afternoon Shade in Combination with Traffic Stress on Seashore Paspalum." HortScience 38, no. 6 (October 2003): 1218–22. http://dx.doi.org/10.21273/hortsci.38.6.1218.
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Turfgrasses are often exposed to different shade environments in conjunction with traffic stresses (wear and/or compaction) in athletic fields within stadiums. The objective of this study was to assess the effects of morning shade (AMS) and afternoon shade (PMS) alone and in combination with wear and wear plus soil compaction on `Sea Isle 1 seashore paspalum (Paspalum vaginatum Swartz). The study was conducted using two consecutive field trials under sports field conditions from 9 July to 10 Sept. 2001 at the Univ. of Georgia Experiment Station at Griffin. “T” shaped structures constructed of plywood on the sports field were used to provide §90% morning and afternoon shade, respectively, and were in place for 1 year prior to data accumulation. A wear device and a studded roller device simulated turfgrass wear (WD) and wear plus soil compaction (WSC), respectively, to the shaded plots. Only minor differences in turf color, density, or canopy spectral reflectance were found between AMS and PMS under no-traffic treatments in both trials. Grasses under WD generally recovered faster than those exposed to WSC across all light levels, including full sunlight (FL), AMS, and PMS. AMS combined with WD treatment had an average 9% higher rating of color, 11% higher density, and 28% less tissue injury than that of PMS with WD at 7 days after traffic treatment (DAT). Compared to PMS with WSC treatment at 7 DAT, AMS with WSC had 12% higher rating of color, 9% higher density, and 4% less tissue injury. AMS with WD treatment exhibited 11% higher normalized difference vegetation index (NDVI), 4% higher canopy water band index (CWBI), and 13% lower stress index than that of PMS with WD at 7 DAT. AMS with WSC, relative to PMS with WSC, demonstrated 8% higher NDVI, 3% higher CWBI, and 8% lower stress index at 7 DAT. Re sults indicated that AMS (i.e., afternoon sunlight) had less detrimental influences than PMS (i.e., morning sunlight) on turfgrass performance after it was subjected to wear stress or wear plus soil compaction.
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Winhausen, Lisa, Jop Klaver, Joyce Schmatz, Guillaume Desbois, Janos L. Urai, Florian Amann, and Christophe Nussbaum. "Micromechanisms leading to shear failure of Opalinus Clay in a triaxial test: a high-resolution BIB–SEM study." Solid Earth 12, no. 9 (September 23, 2021): 2109–26. http://dx.doi.org/10.5194/se-12-2109-2021.
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Abstract. A microphysics-based understanding of mechanical and hydraulic processes in clay shales is required for developing advanced constitutive models, which can be extrapolated to long-term deformation. Although many geomechanical tests have been performed to characterise the bulk mechanical, hydro-mechanical, and failure behaviour of Opalinus Clay, important questions remain about micromechanisms: how do microstructural evolution and deformation mechanisms control the complex rheology? What is the in situ microstructural shear evolution, and can it be mimicked in the laboratory? In this contribution, scanning electron microscopy (SEM) was used to image microstructures in an Opalinus Clay sample deformed in an unconsolidated–undrained triaxial compression test at 4 MPa confining stress followed by argon broad ion beam (BIB) polishing. Axial load was applied (sub-)perpendicular to bedding until the sample failed. The test was terminated at an axial strain of 1.35 %. Volumetric strain measurements showed bulk compaction throughout the compression test. Observations on the centimetre to micrometre scale showed that the samples exhibited shear failure and that deformation localised by forming a network of micrometre-wide fractures, which are oriented with angles of 50∘ with respect to horizontal. In BIB–SEM at the grain scale, macroscale fractures are shown to be incipient shear bands, which show dilatant intergranular and intragranular microfracturing, granular flow, bending of phyllosilicate grains, and pore collapse in fossils. Outside these zones, no deformation microstructures were observed, indicating only localised permanent deformation. Thus, micromechanisms of deformation appear to be controlled by both brittle and ductile processes along preferred deformation bands. Anastomosing networks of fractures develop into the main deformation bands with widths up to tens of micrometres along which the sample fails. Microstructural observations and the stress–strain behaviour were integrated into a deformation model with three different stages of damage accumulation representative for the deformation of the compressed Opalinus Clay sample. Results on the microscale explain how the sample locally dilates, while bulk measurement shows compaction, with an inferred major effect on permeability by an increase in hydraulic conductivity within the deformation band. Comparison with the microstructure of highly strained Opalinus Clay in fault zones shows partial similarity and suggests that during long-term deformation additional solution–precipitation processes operate.
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Ju, J. W., K. Y. Yuan, A. W. Kuo, and J. S. Chen. "Novel Strain Energy Based Coupled Elastoplastic Damage and Healing Models for Geomaterials – Part II: Computational Aspects." International Journal of Damage Mechanics 21, no. 4 (August 17, 2011): 551–76. http://dx.doi.org/10.1177/1056789511407360.
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In Part I of this sequel (Ju, J.W., Yuan, K.Y. and Kuo, A.W. (2010). Novel Strain Energy Based Coupled Elastoplastic Damage and Healing Models for Geomaterials – Part I: Formulations, International Journal of Damage Mechanics, DOI: 10.1177/1056789511407359), we have developed innovative strain energy based coupled elastoplastic hybrid isotropic and anisotropic damage-healing formulations for geomaterials under complex 2D earth-moving processes. Emanating from a micromechanics-based brittle (tensile) damage characterization (P+) and a ductile (mixed tension–compression) damage-healing characterization ([Formula: see text]), the proposed hybrid isotropic and anisotropic damage-healing models for soils are implemented. Entirely new computational algorithms are systematically developed based on the two-step operator splitting methodology. The elastic damage-healing predictor and the plastic corrector are consistently implemented within the existing Nonlinear Meshfree Analysis Program at University of California, Los Angeles ( Chen, J.S., Wu, C.T., Yoon, S. and You, Y. (2001) . A Stabilized Conforming Nodal Integration for Galerkin Meshfree Methods, International Journal for Numerical Methods in Engineering, 50: 435–466). Several numerical simulations featuring sophisticated earth excavation, transport, compaction, and a numerical notched soil bar under cyclic tension–compression loading are presented to illustrate the salient elastoplastic damage and healing features of soils, such as shear band and partial recovery of soil stiffness due to compression (compaction) by the proposed innovative damage-healing models and step-by-step computational algorithms.
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Charalampidou, E. M., H. Stephen, S. Sergei, V. Gioachino, and L. Helen. "Experimental characterisation of shear and compaction band mechanisms in porous sandstone by a combination of AE and 3D-DIC." EPJ Web of Conferences 6 (2010): 22009. http://dx.doi.org/10.1051/epjconf/20100622009.
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Gourlay, C. M., T. Nagira, Kentaro Uesugi, and Hideyuki Yasuda. "In Situ Study of the Altering Globule Packing-Density during Semisolid Alloy Deformation." Solid State Phenomena 192-193 (October 2012): 185–90. http://dx.doi.org/10.4028/www.scientific.net/ssp.192-193.185.
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Synchrotron radiography experiments are overviewed that directly image semi-solid deformation at the globule-scale. Globular Al-15Cu at 50-60% solid was deformed in direct-shear at 10-2 s-1. Deformation is shown to occur by globule rearrangement without discernible deformation of the individual globules. Globules were found to translate and rotate as quasi-discrete bodies in response to forces acting at globule-globule contacts, similar to liquid-saturated granular materials such as water-saturated sand. Rearrangement caused the globule packing-density (the solid fraction) to adjust by local compaction and local dilation of the globule assembly, and deformation is highly inhomogeneous. During shear, there was a net dilation and strain began to localize into a shear band of decreased solid fraction by the end of the experiments.
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Hao, Xiaopeng, Chunlan Zhou, Runsheng Yu, Baoyi Wang, and Long Wei. "Characterization of Implantation Induced Defects in Si-Implanted SiO2 Film." Journal of Nanoscience and Nanotechnology 8, no. 3 (March 1, 2008): 1350–54. http://dx.doi.org/10.1166/jnn.2008.327.
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Si-implanted thermal SiO2 layers and their annealing behaviour were investigated. In the results of variable-energy positron annihilation spectroscopy, the defects caused by ion implantation are manifested as a particularly low S parameter in the Si ion implantation region of the SiO2 layer. Compared with Fourier transform infrared measurements, it suggests that the decrease of the line shape S parameter after implantation is related to the compaction of implanted layers induced by the breaking of the SiO2 network structure. The presence of blue band emission (430–470 nm) in the implanted SiO2 layer is associated with neutral oxygen vacancy. An increase of the S parameter in the implanted layers is observed after annealing at different temperatures, but it is impossible completely recover the pre-implantation condition after a thermal treatment.
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Saravanamuttu, Kalaichelvi, Xin Min Du, S. Iraj Najafi, and Mark P. Andrews. "Article." Canadian Journal of Chemistry 76, no. 11 (November 1, 1998): 1717–29. http://dx.doi.org/10.1139/v98-176.
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The solution sol-gel method is used to produce thin films of photosensitive hybrid organic-inorganic glass on silicon. Glasses consisted of photoinitiator, methacryloxypropyltrimethoxysilane, methacrylic acid, and zirconium oxide. Clear, low optical loss films are obtained, indicating nanophase homogeneity in the samples. The nanocomposite films are shown to be suitable for fabricating optical components such as ridge wave guides and Bragg diffraction gratings. The increase in the refractive index of the glass relative to the surrounding material during photolithographic processing is identified as a key material parameter in device fabrication. Accordingly, electronic and vibrational spectroscopy are used to provide insight into the structural changes that occur when glasses are irradiated with continuous narrow band 4.9 eV and pulsed 6.4 eV light. Arguments are advanced, linking the changes in refractive index to collateral densification leading to volume compaction of the silicate network during organic free-radical polymerization. This was shown by following the time evolution of relevant IR absorption bands. Free silanol and unreacted methoxysilane are consumed in the process. Matrix densification is indicated by shifts to low wave number in the transverse optical phonon mode associated with decreasing Si-O-Si bond angles of the antisymmetric stretching vibration (compression). Growth in the Si-O-Si framework is observed through increased intensity in this IR absorption. Similar behaviour is observed for films irradiated with 6.4 eV light from an excimer laser. A phase mask in combination with pulsed 6.4 eV light is used to inscribe a 1.5 mm, high-reflectivity polarization-independent Bragg grating into a ridge wave guide. The high reflectivity is thought to arise from a periodic modulation of the volume compaction of the matrix. Overall, the organic component of the glass confers unique properties on the material that allow it to be densified even with 4.9 eV light. By comparison, sol-gel silica with no organic component must be densified at nearly twice the photon energy.Key words: sol-gel, wave guide, Bragg grating, photochemistry, densification, refractive index, photolithography.
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Shen, Jianhua, Xing Wang, Wenbai Liu, Poyu Zhang, Changqi Zhu, and Xinzhi Wang. "Experimental Study on Mesoscopic Shear Behavior of Calcareous Sand Material with Digital Imaging Approach." Advances in Civil Engineering 2020 (November 20, 2020): 1–11. http://dx.doi.org/10.1155/2020/8881264.
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The study of the mesostructure of soil under loading is the basis for understanding its macromechanical properties and for establishing its constitutive model. In this study, a series of shear tests was performed on dry calcareous sand under constant normal stress by a modified direct shear apparatus. Digital images of the sample at different shear stages are obtained. The mesostructural parameters of the sample are then extracted and analyzed using an image analysis technique. The results show that the shear-band is located at the junction of the upper and lower shear boxes with a thickness of 0.79–1.59 mm. During shearing, the position of the maximum shear strain incremently shifted to the junctions between the two shear boxes. The azimuths of the particles prior to the test distribute symmetrically on both sides of 90°. After the test, the azimuths of the particles are mainly obtuse angles (150–180°) and the long axis of the particles generally points in the opposite direction from the shear-band. The sand particles undergo four stages: random arrangement during initial sample preparation, compaction under normal stress, particle rotation during shearing, and ordered alignment after shearing. The test results help to reveal the movement mechanism of calcareous sand at the mesoscopic level during the direct shear process.
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Wilson, Robert, Nigel A. Stone, and Mark A. Gibson. "Extrusion of CP Grade Titanium Powders Eliminating the Need for Hot Pre-Compaction via Hot Isostatic Pressing." Materials Science Forum 534-536 (January 2007): 801–4. http://dx.doi.org/10.4028/www.scientific.net/msf.534-536.801.
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Extrusion is a way to produce near net shape components from CP grade titanium powders of optimum density with minimum porosity and acceptable mechanical properties. Chemically pure, hydride/dehydride titanium powders were cold pre-compacted and extruded at 850oC under an argon atmosphere. The extrusion stress required was ~450MPa. To characterize the extrusions, the porosity distribution, qualitative microstructure and tensile properties were evaluated and compared with conventional extruded wrought titanium. Extrusion occurred after the green billets were upset to ~100% of theoretical density and adequate lubrication was applied to the die. The resultant product was 100% dense with a narrow band of surface porosity and exhibited an equiaxed microstructure of similar magnitude to the starting material. The tensile properties of the bars were observed to be significantly superior to conventionally extruded CP titanium bar products, a result associated with the much finer average grain size. Outcomes from this study have assisted in the identification of a number of key characteristics important to the extrusion of titanium from pre-compacted CP titanium powders, allowing the elimination of canning and hot isostatic pressing (HIPping) of billets prior to extrusion as per conventional PM processes.
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Chen, Xiao, Klaus Regenauer-Lieb, and Hamid Roshan. "Temperature-Induced Ductile–Brittle Transition in Porous Carbonates and Change in Compaction Band Growth Revealed by 4-D X-Ray Tomography." Rock Mechanics and Rock Engineering 55, no. 3 (January 4, 2022): 1087–110. http://dx.doi.org/10.1007/s00603-021-02736-0.
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Song, Hyeonju, and Yung-Lyul Lee. "Inverse Transform Using Linearity for Video Coding." Electronics 11, no. 5 (March 1, 2022): 760. http://dx.doi.org/10.3390/electronics11050760.
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In hybrid block-based video coding, transform plays an important role in energy compaction. Transform coding converts residual data in the spatial domain into frequency domain data, thereby concentrating energy in a lower frequency band. In VVC (versatile video coding), the primary transform is performed using DCT-II (discrete cosine transform type 2), DST-VII (discrete sine transform type 7), and DCT-VIII (discrete cosine transform type 8). Considering that DCT-II, DST-VII, and DCT-VIII are all linear transforms, inverse transform is proposed to reduce the number of computations by using the linearity of transform. When the proposed inverse transform using linearity is applied to the VVC encoder and decoder, run-time savings can be achieved without decreasing the coding performance relative to the VVC decoder. It is shown that, under VVC common-test conditions (CTC), average decoding time savings values of 4% and 10% are achieved for all intra (AI) and random access (RA) configurations, respectively.
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Rozitis, B., A. J. Ryan, J. P. Emery, P. R. Christensen, V. E. Hamilton, A. A. Simon, D. C. Reuter, et al. "Asteroid (101955) Bennu’s weak boulders and thermally anomalous equator." Science Advances 6, no. 41 (October 2020): eabc3699. http://dx.doi.org/10.1126/sciadv.abc3699.
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Thermal inertia and surface roughness are proxies for the physical characteristics of planetary surfaces. Global maps of these two properties distinguish the boulder population on near-Earth asteroid (NEA) (101955) Bennu into two types that differ in strength, and both have lower thermal inertia than expected for boulders and meteorites. Neither has strongly temperature-dependent thermal properties. The weaker boulder type probably would not survive atmospheric entry and thus may not be represented in the meteorite collection. The maps also show a high–thermal inertia band at Bennu’s equator, which might be explained by processes such as compaction or strength sorting during mass movement, but these explanations are not wholly consistent with other data. Our findings imply that other C-complex NEAs likely have boulders similar to those on Bennu rather than finer-particulate regoliths. A tentative correlation between albedo and thermal inertia of C-complex NEAs may be due to relative abundances of boulder types.
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Strozzi, Tazio, Dora Carreon-Freyre, and Urs Wegmüller. "Land subsidence and associated ground fracturing: study cases in central Mexico with ALOS-2 PALSAR-2 ScanSAR Interferometry." Proceedings of the International Association of Hydrological Sciences 382 (April 22, 2020): 179–82. http://dx.doi.org/10.5194/piahs-382-179-2020.
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Abstract. Land subsidence affects highly developed urban areas in central Mexico, where inhabitants rely on groundwater for about 60 % of water supply and most of the cities are located in volcanic valleys filled with fine and coarse grained sediments. Compaction associated to groundwater depletion in areas with subsoil contacts sediments-rock have caused differential subsidence, ground fracturing and eventually the reactivation of pre-existing faults, depending on the local geological setting. Remote sensing monitoring methods of land deformation have proved to be useful tools to assess this geological hazard for urban planning. We used L-band ScanSAR data from the ALOS-2 PALSAR-2 mission to produce a regional land subsidence map over an area of about 350 km × 350 km over central Mexico. Our results indicate with a remarkable spatial coverage widespread land subsidence over the major cities, which is ranging from more than 30 cm yr−1 in Mexico City to 5–10 cm yr−1 in other locations.
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Meilakh, A. G., Yu V. Kontsevoy, I. O. Gilev, and A. B. Shubin. "Two-layer copper-based powder electrocontact." Physics and Chemistry of Materials Treatment, no. 6 (2021): 54–60. http://dx.doi.org/10.30791/0015-3214-2021-6-54-60.
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The influence of various schemes of pressure treatment (pressing, rolling) and modes of heat treatment of powder mixtures on the service properties and adhesion strength of the working and current-carrying layers of electrical contacts with a conductivity of at least 75 % of the copper conductivity was investigated. The dependence of the permissible fraction of the working layer in the total contact thickness on its resistivity has been established. It was calculated that the thickness of the working layer of the created electro-contacts of two compositions : 97 % Cu + 1 % C A + 2 % PS (1) and 97.5 % Cu + 1 % C A + 0.5 % PS + 1 % Al2O3 (2), where CA — is activated carbon, PS — (Fe – Cu) nanocrystalline pseudo-alloy with electrical resistance of 3.20 and 3.28 μOhm·cm, respectively, can be increased to the thickness of the copper layer. The composition of the anti-deformation band for the copper layer of contacts — stainless steel is substantiated and selected, the dimensions of the band are calculated. In all cases of pressure treatment, sintering of samples in hydrogen were carried out twice: the first stage (reduction) — after compaction to a porosity of ~ 20 %, the second stage — after final pressure treatment. For sintered materials, the density, hardness, electrical resistance and its maximum spread over the cross section of cylindrical specimens, as well as the strength of adhesion of the working and base layers, were determined. According to the characteristics of the properties of contact materials and manufacturability of their creation, the advantage of the method of their preparation was evaluated. Optimal of the considered processes for producing contacts, comprising a joint rolling with a reduction of 50 % of copper powder and the powder mixture for the working layer (when using the metering hoppers separated for the charge of each layer), sintering at 600 °C, 1 hour, re-compacting rolling with strain 85 % and sintering at 800 °С for 1 hour. This method was used to obtain samples of contacts, which, depending on the composition of the working layer, have a relative density of 0.99 and 0.98, hardness HB 990 and 830 MPa, electrical resistance 2.57 and 2.61 μOhm·cm and adhesion strength of layers > 200 MPa (breaking stress for copper).
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Keleş, Ali, and Cangül Keskin. "Presence of voids after warm vertical compaction and single‐cone obturation in band‐shaped isthmuses using micro‐computed tomography: A phantom study." Microscopy Research and Technique 83, no. 4 (April 2020): 370–74. http://dx.doi.org/10.1002/jemt.23423.
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Liu, K., and J. Zhao. "Progressive Damage Behaviours of Triaxially Confined Rocks under Multiple Dynamic Loads." Rock Mechanics and Rock Engineering 54, no. 6 (May 5, 2021): 3327–58. http://dx.doi.org/10.1007/s00603-021-02408-z.
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AbstractInvestigation of rock progressive damage under static confinement and strain rates facilitates the generation mechanism of natural fault damage zones. A triaxial Hopkinson bar apparatus is used to perform dynamic triaxial compression tests to examine the damage and degradation process of rocks subjected to multiple impacts. Dynamic mechanical properties are determined under a static triaxial pre-stress of (30, 20, 10) MPa and multiple dynamic loadings, with the repetitive impact velocity of 27 m/s and strain rates from 50 to 150/s. The acoustic characteristics are identified by ultrasonic measurement to qualify the damage values. The micro-crack parameters, including crack area and volumes are detected using synchrotron X-ray micro-computed tomography (μCT) to characterize the progressive damage. In addition, the microcrack orientation, density and fractal dimension are analysed from thin section. Experimental results show that dynamic stress-strain curves can be divided to elastic, nonlinear deformation and unloading phases. Dynamic peak stress, Young’s modulus and ultrasonic wave velocity decrease with increasing impact times. The high frequency of ultrasonic wave is filtered by the induced microcracks. The progressive damage and evolution of fracture networks are associated highly with microcrack initiation, propagation, branching and coalescence. Shear bands are commonly generated in granite, and tensile cracks are dominant in marble, while sandstone is mainly failed by compaction and deformation band. The absorbed energy of rock increases nonlinearly with increasing crack surface and volume. Besides, microcracks propagate primarily along the maximum principal stress; the density and fractal dimension exhibit an anisotropic distribution controlled by true triaxial confinement and dynamic impacts.
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Winston, EC. "Evaluation of paclobutrazol on growth, flowering and yield of mango cv. Kensington Pride." Australian Journal of Experimental Agriculture 32, no. 1 (1992): 97. http://dx.doi.org/10.1071/ea9920097.
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The growth retardant paclobutrazol was applied after harvest as a foliar spray, a band along the drip line, or a collar drench in trials over 3 years on 3-, 4-, and 5-year-old trees of mango cv. Kensington Pride. The trees were assessed for percentage of branches with vegetative flush, flush length, flowering, and yield. Paclobutrazol reduced length of vegetative growth in all trials. Eight mL a.i. per tree, applied as a single yearly collar drench, significantly (P<0.05) reduced percentage flush. Collar treatments were significantly (P<0.05) more effective than drip line treatment in reducing length of vegetative growth. Two years' collar drench was generally more effective than a band treatment followed by a collar drench. In particular, collar drenches of 4 and 8 mL a.i./tree, applied for 2 consecutive years, reduced summer growth. Flowering and cropping were significantly (P<0.05) increased by paclobutrazol in a year of inadequate winter stress, while a trend towards increased yield was noted under more normal conditions. Yield increases were due to fruit numbers rather than size. Fruit colour was unaffected. Soil-applied treatments were more effective on flowering and cropping than foliar treatment, with collar drenches more effective than drip line treatment. A trend for decreasing yields was found when paclobutrazol was applied as a collar drench for 2 consecutive years at the same rate, compared with an ineffective drip line followed by a single collar treatment. Rates of paclobutrazol >4 mL a.i./tree caused unacceptable compaction of flower panicles. Four mL a.i./tree appeared the best application rate given the prevailing soil type, climatic conditions, and tree size and age.
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Celton-Morizur, Séverine, Nicole Bordes, Vincent Fraisier, Phong T. Tran, and Anne Paoletti. "C-Terminal Anchoring of mid1p to Membranes Stabilizes Cytokinetic Ring Position in Early Mitosis in Fission Yeast." Molecular and Cellular Biology 24, no. 24 (December 15, 2004): 10621–35. http://dx.doi.org/10.1128/mcb.24.24.10621-10635.2004.
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ABSTRACT mid1p is a key factor for the central positioning of the cytokinetic ring in Schizosaccharomyces pombe. In interphase and early mitosis, mid1p forms a medial cortical band overlying the nucleus, which may represent a landmark for cytokinetic ring assembly. It compacts before anaphase into a tight ring with other cytokinetic ring components. We show here that mid1p binds to the medial cortex by at least two independent means. First, mid1p C-terminus association with the cortex requires a putative amphipathic helix adjacent to mid1p nuclear localization sequence (NLS), which is predicted to insert directly into the lipid bilayer. This association is stabilized by the polybasic NLS. mid1p mutated within the helix and the NLS forms abnormal filaments in early mitosis that are not properly anchored to the medial cortex. Misplaced rings assemble in late mitosis, indicating that mid1p C-terminus binding to membranes stabilizes cytokinetic ring position. Second, the N terminus of mid1p has the ability to associate faintly with the medial cortex and is sufficient to form tight rings. In addition, we show that mid1p oligomerizes. We propose that membrane-bound oligomers of mid1p assemble recruitment “platforms” for cytokinetic ring components at the medial cortex and stabilize the ring position during its compaction.
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Dimmen, Vilde, Atle Rotevatn, and Casey W. Nixon. "The Relationship between Fluid Flow, Structures, and Depositional Architecture in Sedimentary Rocks: An Example-Based Overview." Geofluids 2020 (July 14, 2020): 1–19. http://dx.doi.org/10.1155/2020/3506743.
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Fluid flow in the subsurface is fundamental in a variety of geological processes including volcanism, metamorphism, and mineral dissolution and precipitation. It is also of economic and societal significance given its relevance, for example, within groundwater and contaminant transport, hydrocarbon migration, and precipitation of ore-forming minerals. In this example-based overview, we use the distribution of iron oxide precipitates as a proxy for palaeofluid flow to investigate the relationship between fluid flow, geological structures, and depositional architecture in sedimentary rocks. We analyse and discuss a number of outcrop examples from sandstones and carbonate rocks in New Zealand, Malta, and Utah (USA), showing controls on fluid flow ranging from simple geological heterogeneities to more complex networks of structures. Based on our observations and review of a wide range of the published literature, we conclude that flow within structures and networks is primarily controlled by structure type (e.g., joint and deformation band), geometry (e.g., length and orientation), connectivity (i.e., number of connections in a network), kinematics (e.g., dilation and compaction), and interactions (e.g., relays and intersections) within the network. Additionally, host rock properties and depositional architecture represent important controls on flow and may interfere to create hybrid networks, which are networks of combined structural and stratal conduits for flow.
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Feng, Luwei, Zhou Zhang, Yuchi Ma, Qingyun Du, Parker Williams, Jessica Drewry, and Brian Luck. "Alfalfa Yield Prediction Using UAV-Based Hyperspectral Imagery and Ensemble Learning." Remote Sensing 12, no. 12 (June 24, 2020): 2028. http://dx.doi.org/10.3390/rs12122028.
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Alfalfa is a valuable and intensively produced forage crop in the United States, and the timely estimation of its yield can inform precision management decisions. However, traditional yield assessment approaches are laborious and time-consuming, and thus hinder the acquisition of timely information at the field scale. Recently, unmanned aerial vehicles (UAVs) have gained significant attention in precision agriculture due to their efficiency in data acquisition. In addition, compared with other imaging modalities, hyperspectral data can offer higher spectral fidelity for constructing narrow-band vegetation indices which are of great importance in yield modeling. In this study, we performed an in-season alfalfa yield prediction using UAV-based hyperspectral images. Specifically, we firstly extracted a large number of hyperspectral indices from the original data and performed a feature selection to reduce the data dimensionality. Then, an ensemble machine learning model was developed by combining three widely used base learners including random forest (RF), support vector regression (SVR) and K-nearest neighbors (KNN). The model performance was evaluated on experimental fields in Wisconsin. Our results showed that the ensemble model outperformed all the base learners and a coefficient of determination (R2) of 0.874 was achieved when using the selected features. In addition, we also evaluated the model adaptability on different machinery compaction treatments, and the results further demonstrate the efficacy of the proposed ensemble model.
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Wang, Z. H., Y. L. Tan, S. M. Li, T. Z. Wang, and X. C. Wu. "Experimental and Numerical Study on Mechanical Properties and Deformation Behavior of Beishan Granite considering Heterogeneity." Advances in Civil Engineering 2021 (April 22, 2021): 1–13. http://dx.doi.org/10.1155/2021/6622958.
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Disposal of high-level radioactive waste (HLW) deep underground is one of the most challenging research subjects in rock engineering. In China, Beishan granite is usually chosen as host rock for the construction of the HLW repository. In this study, mechanical tests are conducted on Beishan granite and the stress-strain state during the complete failure process is analyzed by numerical simulation. The results show that the tensile strength and uniaxial compressive strength of Beishan granite are 8.66 and 162.9 MPa, respectively. Dilatancy appears when the stress reaches about 81% of the peak strength. Heterogeneity is introduced by Weibull distribution in numerical simulation. With the increase of homogenization degree, the degraded elements are more easily to concentrate locally. Based on experimental and numerical simulation results, it is noticeable that the sample volume is basically in the state of compaction before reaching the peak strength. The elements are more likely to show expansion, and the splitting failure dominates the destroy mode when the confining pressure is relatively low. With increasing confining pressure, more and more degraded elements are concentrated in the shear band, which develops from the surface to the interior of the sample during loading. Therefore, the granite shows ductile mechanical response characteristics when the confining pressure is relatively high. The results are instructive for the construction of the repository.
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Brown, Michael. "The mechanism of melt extraction from lower continental crust of orogens." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 95, no. 1-2 (March 2004): 35–48. http://dx.doi.org/10.1017/s0263593300000900.
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ABSTRACTMelt extraction is a process with a length scale that spans many orders of magnitude. Studies of residual migmatites and granulites suggest that melt has migrated from grain boundaries to networks of leucosome-filled structures to steeply inclined cylindrical or tabular granites inferred to have infilled ascent conduits. For example, in anatectic rocks from southern Brittany, France, during decompression-induced biotite-breakdown melting, melt is inferred to have been expressed from foliation-parallel structures analogous to compaction bands to dilation and shear bands, based on location of residual leucosome, and from this network of structures to ascent conduits, preserved as dykes of granite. The leucosome-filled deformation band network is elongated parallel to a sub-horizontal lineation, suggesting that mesoscale melt flow was focused primarily in the plane of the foliation along the lineation to developing dilatant transverse structures. The leucosome network connects with petrographic continuity to granite in dykes; however, the orientation of dykes discordant to fabric anisotropy suggests that their formation was controlled by stress, which indicates that the process is a fracture phenomenon. Blunt fracture tips and zigzag propagation paths indicate that the dykes represent ductile opening-mode fractures; these are postulated to have formed by coalescence of melt pockets. The structures record a transition from accumulation to draining; quantitative volume fluxes are calculated and presented for the generalised extraction process. The anatectic system may have converged to a critical state at some combination of melt fraction and melt distribution that enabled formation of ductile opening-mode fractures, but fractal distribution of inferred mesoscale melt-filled structures has not been demonstrated; this may reflect the inherent anisotropy and/or residual nature of the drained source. Melt extraction has been modelled as a self-organised critical phenomenon, but the mechanism of extraction is not described and the relationship between these models and the spatial and temporal granularity of lower continental crust is not addressed. Self-organised critical phenomena are driven systems involving ‘avalanches’ with a fractal frequency-size distribution; thus, the distribution of melt batch sizes might be expected to be fractal, but this has not yet been demonstrated in nature.
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Li, Guangrong, Chaoying Zhao, Baohang Wang, Xiaojie Liu, and Hengyi Chen. "Land Subsidence Monitoring and Dynamic Prediction of Reclaimed Islands with Multi-Temporal InSAR Techniques in Xiamen and Zhangzhou Cities, China." Remote Sensing 14, no. 12 (June 19, 2022): 2930. http://dx.doi.org/10.3390/rs14122930.
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Artificial islands and land reclamation are one of the most important ways to expand urban space in coastal cities. Long-term consolidation of reclaimed material and compaction of marine sediments can cause ground subsidence, which may threaten the buildings and infrastructure on the reclaimed lands. Therefore, it is crucial to monitor the land subsidence and predict the future deformation trend to mitigate the damage and take measures for the land reclamation and any infrastructure. In this paper, a total of 125 SAR images acquired by the C-band Sentinel-1A satellite between June 2017 and September 2021 are collected. The small baseline subsets (SBAS) SAR interferometry (InSAR) method is first conducted to detect the land deformation in Xiamen and Zhangzhou cities of Fujian Province, China, and the distributed scatterers (DS)-InSAR method is used to recover the complete deformation history of some typical areas including Xiamen Airport in Dadeng Island and Shuangyu Island. Then, the sequential estimation and the geotechnical model are jointly applied to demonstrate the current and future evolution of land subsidence of the constructed roads on Shuangyu Island. The results show that the maximum cumulative deformation reaches 425 mm of Xiamen Xiang’an Airport and 626 mm of Shuangyu Island, and the maximum deformation is predicted to be as large as 1.1 m by 2026 of Shuangyu Island. This research will provide important guidelines for the design and construction of Xiamen Xiang’an Airport and Shuangyu Island to prevent and control land subsidence.
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Paz Pellat, Fernando. "Correcciones atmosféricas relativas de imágenes de satélite: patrones invariantes y modelos atmosféricos." REVISTA TERRA LATINOAMERICANA 36, no. 1 (January 22, 2018): 1. http://dx.doi.org/10.28940/terra.v36i1.228.
Full textAbstract:
To use information obtained with satellite technology reliably, it is necessary to eliminate or reduce the disruptive effects associated with the spectral information captured by sensors on space platforms. In this paper we analyze the inversion of radiative models of the atmosphere, which consists in determining the additive and multiplicative constants in each spectral band to make the necessary atmospheric corrections. The methodology proposes the use of invariant patterns of soil lines and dense vegetation for the inversion of radiative models. The results showed that, without knowledge of the atmospheric model or the type of aerosol, soil line data were relatively insufficient (low correlation) to obtain the additive and multiplicative constants of the atmospheric inversions, with problems of multiple solutions in the inversion process. Under similar conditions, the same was found for additive constants with the dense vegetation line, but for the multiplicative constants the results were favorable (R2 > 0.9). In contrast, with the knowledge of the atmospheric model and the aerosol model, estimates of additive and multiplicative constants were highly satisfactory (R2 > 0.99) in both cases. For soil line inversions, only one constraint of the two available was used. In conclusion, the use of invariant soil-line patterns allows us to establish two basic relationships to invert the radiative simulations of the atmosphere, prior to functional compaction, and field measurements can be made so that the proposed atmospheric correction process in this work can be considered in absolute and not relative terms.