Thematische Bibliographien / Crater morphology

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Auswahl der wissenschaftlichen Literatur zum Thema „Crater morphology“

Autor: Grafiati

Veröffentlicht am 28. Juni 2021

Zuletzt aktualisiert am 5. Februar 2022

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Zeitschriftenartikel zum Thema "Crater morphology"

Hu, Bo, Song Lin Ding, Christopher Lim, Milan Brandt und John Mo. „Measurement of Polycrystalline Diamond Craters in Electrical Discharge Machining“. Applied Mechanics and Materials 664 (Oktober 2014): 304–9. http://dx.doi.org/10.4028/www.scientific.net/amm.664.304.

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The electrical discharge grinding method is widely used to machine polycrystalline diamond tools because diamond is the hardest material and the traditional abrasive grinding method leads to high tool wear rate. The aim of this study was to find a method to precisely measure the individual diamond crate morphology during the electrical discharge process. A 3D microscopy with the focus-variation technique was chosen to obtain the stereolithography file of the polycrystalline diamond craters. The measurements were shown that the polycrystalline diamond crater morphology is more complex than that of normal tungsten carbide material. This finding can help build more accurate model of polycrystalline crater formation during electrical discharge process.

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Badr, Sarah, Georges Gauthier und Philippe Gondret. „Crater jet morphology“. Physics of Fluids 28, Nr. 3 (März 2016): 033305. http://dx.doi.org/10.1063/1.4943160.

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Li, B., Z. C. Ling, J. Zhang, J. Chen, C. Q. Liu und X. Y. Bi. „GEOLOGICAL MAPPING OF LUNAR CRATER LALANDE: TOPOGRAPHIC CONFIGURATION, MORPHOLOGY AND CRATERING PROCESS“. ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3/W1 (25.07.2017): 77–83. http://dx.doi.org/10.5194/isprs-archives-xlii-3-w1-77-2017.

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Highland crater Lalande (4.45°&thinsp;S, 8.63°&thinsp;W; D&thinsp;=&thinsp;23.4&thinsp;km) is located on the PKT area of the lunar near side, southeast of Mare Insularum. It is a complex crater in Copernican era and has three distinguishing features: high silicic anomaly, highest Th abundance and special landforms on its floor. There are some low-relief bulges on the left of crater floor with regular circle or ellipse shapes. They are ~&thinsp;250 to 680&thinsp;m wide and ~&thinsp;30 to 91&thinsp;m high with maximum flank slopes >&thinsp;20°. There are two possible scenarios for the formation of these low-relief bulges which are impact melt products or young silicic volcanic eruptions. According to the absolute model ages of ejecta, melt ponds and hummocky floor, the ratio of diameter and depth, similar bugle features within other Copernican-aged craters and lack of volcanic source vents, we hypothesized that these low-relief bulges were most consistent with an origin of impact melts during the crater formation instead of small and young volcanic activities occurring on the crater floor. Based on Kaguya TC ortho-mosaic and DTM data produced by TC imagery in stereo, geological units and some linear features on the floor and wall of Lalande have been mapped. Eight geological units are organized by crater floor units: hummocky floor, central peak and low-relief bulges; and crater wall units: terraced walls, channeled and veneered walls, interior walls, mass wasting areas, blocky areas, and melt ponds. These geological units and linear features at Lalande provided us a chance to understand some details of the cratering process and elevation differences on the floor. We evaluated several possibilities to understand the potential causes for the observed elevation differences on the Lalande's floor. We proposed that late-stage wall collapse and subsidence due to melt cooling could be the possible causes of observed elevation differences on the floor.

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Wang, Y., X. Tong, H. Xie, M. Jiang, Y. Huang, S. Liu, X. Xu, Q. Du, Q. Wang und C. Wang. „CRATER DETECTION USING TEXTURE FEATURE AND RANDOM PROJECTION DEPTH FUNCTION“. ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences V-3-2020 (03.08.2020): 603–8. http://dx.doi.org/10.5194/isprs-annals-v-3-2020-603-2020.

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Abstract. In this paper, a novel automatic crater detection algorithm (CDA) based on traditional texture feature and random projection depth function has been proposed. By using traditional texture feature, mathematical morphology is used to identify crater initially. To further reduce the false detection rate, random projection depth function is used. For this purpose, firstly, gray level co-occurrence matrix and a novel grade level co-occurrence matrix are both used to further obtain the texture features of these candidate craters. Secondly, based on the above collected features, random projection depth function is used to refine the crater candidate detection results. LRO Narrow Angle Camera (NAC) mosaic images (1 m/pixel) and Wide-angle Camera (WAC) mosaic images (100 m/pixel) are used to test the accuracy of proposed method. The experimental results indicate our proposed method is robust to detect craters located in different terrains.

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Hardy, Stuart. „Discrete Element Modelling of Pit Crater Formation on Mars“. Geosciences 11, Nr. 7 (24.06.2021): 268. http://dx.doi.org/10.3390/geosciences11070268.

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Pit craters are now recognised as being an important part of the surface morphology and structure of many planetary bodies, and are particularly remarkable on Mars. They are thought to arise from the drainage or collapse of a relatively weak surficial material into an open (or widening) void in a much stronger material below. These craters have a very distinctive expression, often presenting funnel-, cone-, or bowl-shaped geometries. Analogue models of pit crater formation produce pits that typically have steep, nearly conical cross sections, but only show the surface expression of their initiation and evolution. Numerical modelling studies of pit crater formation are limited and have produced some interesting, but nonetheless puzzling, results. Presented here is a high-resolution, 2D discrete element model of weak cover (regolith) collapse into either a static or a widening underlying void. Frictional and frictional-cohesive discrete elements are used to represent a range of probable cover rheologies. Under Martian gravitational conditions, frictional-cohesive and frictional materials both produce cone- and bowl-shaped pit craters. For a given cover thickness, the specific crater shape depends on the amount of underlying void space created for drainage. When the void space is small relative to the cover thickness, craters have bowl-shaped geometries. In contrast, when the void space is large relative to the cover thickness, craters have cone-shaped geometries with essentially planar (nearing the angle of repose) slope profiles. Frictional-cohesive materials exhibit more distinct rims than simple frictional materials and, thus, may reveal some stratigraphic layering on the pit crater walls. In an extreme case, when drainage from the overlying cover is insufficient to fill an underlying void, skylights into the deeper structure are created. This study demonstrated that pit crater walls can exhibit both angle of repose slopes and stable, gentler, collapse slopes. In addition, the simulations highlighted that pit crater depth only provides a very approximate estimate of regolith thickness. Cone-shaped pit craters gave a reasonable estimate (proxy) of regolith thickness, whereas bowl-shaped pit craters provided only a minimum estimate. Finally, it appears that fresh craters with distinct, sharp rims like those seen on Mars are only formed when the regolith had some cohesive strength. Such a weakly cohesive regolith also produced open fissures, cliffs, and faults, and exposed regolith “stratigraphy” in the uppermost part of the crater walls.

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Zhao, Runchen, Qianyun Zhang, Hendro Tjugito und Xiang Cheng. „Granular impact cratering by liquid drops: Understanding raindrop imprints through an analogy to asteroid strikes“. Proceedings of the National Academy of Sciences 112, Nr. 2 (29.12.2014): 342–47. http://dx.doi.org/10.1073/pnas.1419271112.

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When a granular material is impacted by a sphere, its surface deforms like a liquid yet it preserves a circular crater like a solid. Although the mechanism of granular impact cratering by solid spheres is well explored, our knowledge on granular impact cratering by liquid drops is still very limited. Here, by combining high-speed photography with high-precision laser profilometry, we investigate liquid-drop impact dynamics on granular surface and monitor the morphology of resulting impact craters. Surprisingly, we find that despite the enormous energy and length difference, granular impact cratering by liquid drops follows the same energy scaling and reproduces the same crater morphology as that of asteroid impact craters. Inspired by this similarity, we integrate the physical insight from planetary sciences, the liquid marble model from fluid mechanics, and the concept of jamming transition from granular physics into a simple theoretical framework that quantitatively describes all of the main features of liquid-drop imprints in granular media. Our study sheds light on the mechanisms governing raindrop impacts on granular surfaces and reveals a remarkable analogy between familiar phenomena of raining and catastrophic asteroid strikes.

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Lu, Yintao, Xiaoyong Xu, Xiwu Luan, Shu Jiang, Weimin Ran, Taotao Yang, Fuliang Lyu, Yingfang Zhou und Zhili Yang. „Morphology, internal architectures, and formation mechanisms of mega-pockmarks on the northwestern South China Sea margin“. Interpretation 9, Nr. 4 (01.09.2021): T1043—T1058. http://dx.doi.org/10.1190/int-2020-0175.1.

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Pockmarks, as depression morphology related to fluid escape on the seafloor, are revealed by 3D seismic data on the northwestern South China Sea (SCS) margin. The pockmarks can be classified into two groups based on their various shapes in plan view: the circular group and the elongating group. These pockmarks in the study area could be defined as mega-pockmarks because their maximum diameters can reach to 7.5 km. They commonly develop more than one crater, which are called the central crater and the secondary crater. The seismic data illuminated their complicated internal architectures in the subsurface, as well as their evolution periods, such as the initiation stage, mature stage, and abandonment stage. According to the buried structures and their genesis mechanism, mega-pockmarks could be classified into linear faults-associated pockmarks and volcano-associated pockmarks. The linear fault-associated pockmarks root on the top Middle Miocene, where the linear faults are distributed. The linear faults on the top of fluid reservoir in Middle Miocene act as conduits for fluid seepage. The fluid seepage is driven by the break of balance between the hydrostatic and pore pressure. When the fluid seepage initiates, they will migrate along the linear faults, making the linear feature of pockmarks on the seafloor. Thermogenic gas from deep intervals and biogenic gas from shallow intervals may be fluid sources for the genesis of pockmarks. However, the volcanic activities control the genesis and evolution of volcano-associated pockmarks. Volcano-associated pockmarks root on the craters of volcanoes. The volcanoes underneath the pockmarks provide volcanic hydrothermal solutions, such as phreatomagmatic eruptions through the volcanic craters. The confined fluid seepages make the pockmarks exhibit a more circular shape on the seafloor. Long-term, multiepisode fluid expulsions generate the complicated internal architecture that leads to multicratered mega-pockmarks on the northwestern margin of SCS.

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Qiu, Yanyu, Songlin Yue, Mingyang Wang, Gan Li, Yihao Cheng, Zhangyong Zhao und Zhongwei Zhang. „Experimental Investigation of the Crater Caused by Hypervelocity Rod Projectile Impacting on Rocks“. Shock and Vibration 2020 (24.07.2020): 1–11. http://dx.doi.org/10.1155/2020/9768745.

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To investigate the cratering effects of hypervelocity rod projectile impacting on rocks, a two-stage light gas gun was used to carry out 10 groups of small-scale experiments, whose velocity ranges from 1.5 km/s to 4.1 km/s. After each experiment, the morphology and size of the hypervelocity impacting crater were accurately obtained by using a device for image scanning. According to the morphology of the final crater, the impact crater can be divided into crushing area, spallation area, and radial crack area. Based on the experimental results of steel projectile vertical impacting on granite targets, the relationship between the depth and the diameter of the crater is analyzed, i.e., h/D≈0.1∼0.2; it shows that the depth of the crater is much smaller than the diameter of the crater, and the crater seems to be a shallow dish. The relation between the kinetic energy of the projectile and the size of the crater was discussed. With the increase of the projectile kinetic energy, it is uncertain whether the depth of the crater increases, but the volume of the crater will increase. Lastly, dimensionless analysis of the impact crater was carried out. Specifically, the limitations of point source solutions to hypervelocity rod projectile impact cratering have been proved, and there is no essential difference to calculate the final crater by using the energy scale or the momentum scale.

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Trang, David, Jeffrey J. Gillis-Davis und Joseph M. Boyce. „Absolute model ages from lunar crater morphology“. Journal of Geophysical Research: Planets 120, Nr. 4 (April 2015): 725–38. http://dx.doi.org/10.1002/2014je004639.

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Trego, Kent D. „Neptune's satellites: Implications from impact crater morphology“. Earth, Moon and Planets 49, Nr. 1 (April 1990): 85–90. http://dx.doi.org/10.1007/bf00053998.

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Dissertationen zum Thema "Crater morphology"

Varas, Siriany Germàn. „Air rise through an immersed granular bed : - bulk and surfaces dynamics“. Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 2011. http://tel.archives-ouvertes.fr/tel-00690436.

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When air is injected at the bottom of an immersed granular layer, it crosses the system by percolating or fracturing. It thus forms several paths that reach the free surface of the layer at different locations. In this thesis, we study this process experimentally (for a three and two dimensional setup), numerically and theoretically. First, we focus on the dynamics of the air invading the medium at short and long time scale, when injecting a continuous air flow. At long time, the typical size of the region explored by the air can be accounted for by a diffusion-like process [1]. We also investigate the effect of gravity by tilting the experimental cell. We contrast the results with numerical simulations for the injection of a fixed volume of air, and characterize the morphology of the invasion zone. We show that the typical height and width of the region explored by the air does not depend on the injected volume only, but also on a dimensionless parameter χ which accounts for the relative effects of the gravity and capillarity [2]. Finally, when increasing the water height above the granular layer, successive grain advection and deposition form a crater consisting of two dunes growing and moving apart one from the other. We observe that the typical size of the crater increases logarithmically with time, independently of the gas emission process [3].References -[1] G.Varas, V. Vidal and J.-C. Géminard, Phys. Rev. E. 83, 011302 (2011).[2] G.Varas, V. Vidal and J.-C. Géminard, Phys. Rev. E. 83, 061302 (2011).[3] G.Varas, V. Vidal and J.-C. Géminard, Phys. Rev. E. 79, 021301 (2009).

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Wallis, David. „Modelling impact crater morphology with orthogonal polynomials“. Thesis, University of Kent, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342267.

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Buratin, Stefano. „Pulsed laser ablation of silicon : the influence of beam parameters on ablated crater morphology“. Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8569/.

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Laser micromachining is one of the principal fields where the laser capability to change the material morphology is frequently applied and silicon is still the element most used in the semiconductor and photovoltaic industries despite the recent studies on new materials. Although various models reported in the literature describe the laser material interaction, the relation between the ablated crater morphology and the laser beam parameters remains unclear or does not give methods and equations that can be applied on the engineering environment. The aim of this thesis is to reduce the knowledge gap of the understanding of three laser parameters (pulse duration, energy beam shape, and polarisation) influence on the ablated crater morphology by providing functions and relations that can be applied in the engineering environment. First, a systematic study on laser pulse duration based on two different functions (i.e. thermal-based and non-thermal based) is carried out, then the impact of the thermal effect on crater morphology of two non-standard energy beam distributions (i.e. round flat-top and square-top) is evaluated, and finally the laser polarisation effects in the non-linear laser ablation regime are explored, providing the engineering environment of new functions and relations between laser beam parameters and crater morphology.

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Terschová, Vanda. „Korelace charakteristických signálů laserem buzeného plazmatu“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-444962.

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Laser-induced breakdown spectroscopy (LIBS) is a fast analytical method, but can also be complicated. This spectroscopic method is used to provide a qualitative and quantitative analysis of a sample. The analysis is carried out by capturing the emission radiation of the generated plasma. The accuracy and stability of the measurement is affected by several parameters, such as stability of the laser, physical and chemical properties of the sample, its homogeneity and others, that can not always be eliminated. For this reason other methods are being added to the LIBS experiment that could improve the quality of this analysis. This diploma thesis is focused on a research of the literature on the standardization of laser-induced plasma signal and the possibility of using an acoustic signal for this purpose. For this reason , it is necessary to perform basic experiments and to verify if the acoustic signal correlates with the emission signal. If these signals correlate together, it would be possible to use the acoustic signal for standardization og the LIBS data, which would improve the accuracy of the analysis. In the theoretical part at the beginning other spectroscopic methods are summarised. Then the work is focused on the description of the LIBS method, possible ways of the analysis, standardization of emission signals and its review in the literature. The experimental part is aimed at the study of the acoustic signal that was performed in the framework of this study. At the beginning, there are introduced results of the basic measurements on steel and brass samples. These results were important for an optimization of the experiment. The following section shows the results obtained from the measurements of the acoustic signal on the samples with the same chemical composition but different hardness. At the end the correlation between the acoustic and emission signals is discussed.

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Malinski, Peter T. „An Analysis of Morphometric and Morphologic Relationships in Lunar Pit Craters: The Role of Water“. Ohio University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1429487515.

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Balcerski, Jeffrey. „Modeling and Mapping of the Structural Deformation of Large Impact Craters on the Moon and Mercury“. Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1436539210.

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Bouchard, Jean-Marie. „Morphologie fonctionnelle des systèmes de rétention de l'abdomen chez les Brachyoures (Crustacea Decapoda) : microstructure : implications phylogénétiques et systématiques“. Paris, Muséum national d'histoire naturelle, 2000. http://www.theses.fr/2000MNHN0022.

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Les brachyoures (crabes) sont les seuls décapodes qui possèdent un système de retention permettant de maintenir leur abdomen reployé contre la face ventrale. Chez les groupes les plus basaux, la rétention est appendiculaire ; chez les groupes distaux l'appareil de rétention est du type saillie sternale-fossette abdominale ; dans les groupes très spécialisés ou les plus distaux des brachyoures, le système saillie-fossette est remplacé par une complémentarité sterno-abdominale ou bien il disparaît (perte secondaire). Le passage de la modalité appendiculaire à sternale a favorisé la libération des péréiopodes et une diminution de la dépense énergétique. Le maintien de l'abdomen a pour fonction de protéger les organes reproducteurs et évite à l'abdomen d'être endommagé. L'examen au M. E. B de l'appareil de rétention, chez les formes actuelles et fossiles, met en évidence l'existence de nombreux caractères des saillies de rétention, coxale et sternale, et d'une microstructure qui représente un niveau supérieur des coaptations morpho-fonctionnelles. La morphologie et la structure de la saillie de rétention constituent des critères valides à divers niveaux taxonomiques ; ils pourront être utilises pour déterminer les parentes phylogénétiques. Chez les fossiles, l'examen de cet ensemble de caractères permet de formuler des hypothèses d'ordre taphonomique. L'étude histologique montre la modification de la structure histologique du sternite au niveau de la saillie. L'étude ontogénétique a permis de déterminer le stade de développement au cours duquel se met en place l'appareil et d'observer les importantes modifications de celui-ci au moment de l'exuviation. Une étude a été entreprise afin de déterminer les modalités fonctionnelles de cet appareil. La saillie sternale est apparue indépendamment plusieurs fois chez les brachyoures. La fossette est l'homologue de l'uropode. L'uropode (qui n'est jamais birame) présente plusieurs états dans la lignée brachyourienne : lobe ventral, plaque dorsale, fossette, pièce intercalaire, ou bien il disparaît (perte secondaire). La présence d'un système structural de rétention est une synapomorphie des brachyoures, ce qui soutient la monophylie du groupe

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Tirsch, Daniela [Verfasser]. „Dark Dunes on Mars : Analyses on origin, morphology, and mineralogical composition of the dark material in Martian craters / Daniela Tirsch“. Berlin : Freie Universität Berlin, 2009. http://d-nb.info/102349843X/34.

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„Ponds, Flows, and Ejecta of Impact Cratering and Volcanism: A Remote Sensing Perspective of a Dynamic Moon“. Doctoral diss., 2016. http://hdl.handle.net/2286/R.I.38376.

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abstract: Both volcanism and impact cratering produce ejecta and associated deposits incorporating a molten rock component. While the heat sources are different (exogenous vs. endogenous), the end results are landforms with similar morphologies including ponds and flows of impact melt and lava around the central crater. Ejecta from both impact and volcanic craters can also include a high percentage of melted rock. Using Lunar Reconnaissance Orbiter Camera Narrow Angle Camera (LROC NAC) images, crucial details of these landforms are finally revealed, suggesting a much more dynamic Moon than is generally appreciated. Impact melt ponds and flows at craters as small as several hundred meters in diameter provide empirical evidence of abundant melting during the impact cratering process (much more than was previously thought), and this melt is mobile on the lunar surface for a significant time before solidifying. Enhanced melt deposit occurrences in the lunar highlands (compared to the mare) suggest that porosity, target composition, and pre-existing topography influence melt production and distribution. Comparatively deep impact craters formed in young melt deposits connote a relatively rapid evolution of materials on the lunar surface. On the other end of the spectrum, volcanic eruptions have produced the vast, plains-style mare basalts. However, little was previously known about the details of small-area eruptions and proximal volcanic deposits due to a lack of resolution. High-resolution images reveal key insights into small volcanic cones (0.5-3 km in diameter) that resemble terrestrial cinder cones. The cones comprise inter-layered materials, spatter deposits, and lava flow breaches. The widespread occurrence of the cones in most nearside mare suggests that basaltic eruptions occur from multiple sources in each basin and/or that rootless eruptions are relatively common. Morphologies of small-area volcanic deposits indicate diversity in eruption behavior of lunar basaltic eruptions driven by magmatic volatiles. Finally, models of polar volatile behavior during impact-heating suggest that chemical alteration of minerals in the presence of liquid water is one possible outcome that was previously not thought possible on the Moon.
Dissertation/Thesis
Doctoral Dissertation Geological Sciences 2016

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„Analysis of Spacecraft Data for the Study of Diverse Lunar Volcanism and Regolith Maturation Rates“. Doctoral diss., 2013. http://hdl.handle.net/2286/R.I.20943.

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abstract: Lunar Reconnaissance Orbiter (LRO) and MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft missions provide new data for investigating the youngest impact craters on Mercury and the Moon, along with lunar volcanic end-members: ancient silicic and young basaltic volcanism. The LRO Wide Angle Camera (WAC) and Narrow Angle Camera (NAC) in-flight absolute radiometric calibration used ground-based Robotic Lunar Observatory and Hubble Space Telescope data as standards. In-flight radiometric calibration is a small aspect of the entire calibration process but an important improvement upon the pre-flight measurements. Calibrated reflectance data are essential for comparing images from LRO to missions like MESSENGER, thus enabling science through engineering. Relative regolith optical maturation rates on Mercury and the Moon are estimated by comparing young impact crater densities and impact ejecta reflectance, thus empirically testing previous models of faster rates for Mercury relative to the Moon. Regolith maturation due to micrometeorite impacts and solar wind sputtering modies UV-VIS-NIR surface spectra, therefore understanding maturation rates is critical for interpreting remote sensing data from airless bodies. Results determined the regolith optical maturation rate on Mercury is 2 to 4 times faster than on the Moon. The Gruithuisen Domes, three lunar silicic volcanoes, represent relatively rare lunar lithologies possibly similar to rock fragments found in the Apollo sample collection. Lunar nonmare silicic volcanism has implications for lunar magmatic evolution. I estimated a rhyolitic composition using morphologic comparisons of the Gruithuisen Domes, measured from NAC 2-meter-per-pixel digital topographic models (DTMs), with terrestrial silicic dome morphologies and laboratory models of viscoplastic dome growth. Small, morphologically sharp irregular mare patches (IMPs) provide evidence for recent lunar volcanism widely distributed across the nearside lunar maria, which has implications for long-lived nearside magmatism. I identified 75 IMPs (100-5000 meters in dimension) in NAC images and DTMs, and determined stratigraphic relationships between units common to all IMPs. Crater counts give model ages from 18-58 Ma, and morphologic comparisons with young lunar features provided an additional age constraint of <100 Ma. The IMPs formed as low-volume basaltic eruptions significantly later than previous evidence of lunar mare basalt volcanism's end (1-1.2 Ga).
Dissertation/Thesis
Ph.D. Geological Sciences 2013

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Bücher zum Thema "Crater morphology"

Podenas, Sigitas. Limoniidae & Pediciidae de Suisse. Neuchâtel: Centre suisse de cartographie de la faune, 2006.

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Hypervelocity impact study interim report: The effect of impact angle on crater morphology. [Auburn, Ala.?]: Space Power Institute and Materials Engineering, Auburn University, 1993.

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P, Kauahikaua James, und Geological Survey (U.S.), Hrsg. Morphology of extinct lava tubes and the implications for tube evolution, Chain of Craters Road, Hawaii Volcanoes National Park, Hawaii. Menlo Park, CA: U.S. Geological Survey, 1992.

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Buchteile zum Thema "Crater morphology"

Pina, Pedro, und Jorge S. Marques. „Delineation of Impact Craters by a Mathematical Morphology Based Approach“. In Lecture Notes in Computer Science, 717–25. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-39094-4_82.

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Van Kranendonk, Martin J. „Morphology as an Indictor of Biogenicity for 3.5–3.2 Ga Fossil Stromatolites from the Pilbara Craton, Western Australia“. In Advances in Stromatolite Geobiology, 537–54. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-10415-2_32.

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Lagain, A., S. Bouley, D. Baratoux, C. Marmo, F. Costard, O. Delaa, A. Pio Rossi et al. „Mars Crater Database: A participative project for the classification of the morphological characteristics of large Martian craters“. In Large Meteorite Impacts and Planetary Evolution VI. Geological Society of America, 2021. http://dx.doi.org/10.1130/2021.2550(29).

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ABSTRACT The most recent comprehensive database of Martian impact craters was the result of the work of impact crater scientists (S.J. Robbins and B.M. Hynek) who carefully examined the available high-resolution imagery of Mars. Building on this previous work, we present the result of an alternative approach involving 56 planetary scientists and trained students. A web platform was designed for this purpose. All impact craters larger than 1 km in diameter were classified according to a simplified classification scheme, recording the primary or secondary nature of the crater, and the morphology of the ejecta (single, double, or multiple layered ejecta rampart sinuous [LERS], or low-aspect-ratio layer ejecta [LARLE]). In total, 8445 LERS craters, 24,530 partially buried craters, 55,309 secondary craters, and 288,155 craters in the category “standard” were identified. Our assessment differs for 8145 entries in the original database compiled by Robbins and Hynek, which are not considered to be impact structures. In this work, ~39,000 secondary craters have been associated with 108 primary craters. Coupled to the existing database, the database we propose here offers a complementary way to investigate the geological history of Mars. More specifically, the completion of layered ejecta crater morphologies down to 1 km and the connection established between secondary and primary impact crater sources will allow the implementation of statistical studies to reveal the spatial and temporal evo lution of the impacted material characteristics. Thanks to the simplified classification we performed here, this version of the database can be easily used as a training data set for crater identification algorithms based on machine-learning techniques with the aim to identify smaller impact craters and to automatically define their morphological characteristics. Since it is not possible to confirm an impact structure from remote-sensing data alone, any Martian impact database at this stage remains subjective, and its assessment must be facilitated. The interface we developed for this participative project can be directly used for this purpose and for continuous updates and improvements of this work, in particular, with the latest high-resolution imagery releases such as the CTX global mosaic by J.L. Dickson and others, but also as a platform for building specific databases of craters or any other structures located in a particular region of interest.

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Morgan, Joanna, und Mike Warner. „Morphology of the Chicxulub impact: Peak-ring crater or multi-ring basin?“ In Large meteorite impacts and planetary evolution; II. Geological Society of America, 1999. http://dx.doi.org/10.1130/0-8137-2339-6.281.

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Poag, C. Wylie. „Eastern rim of the Chesapeake Bay impact crater: Morphology, stratigraphy, and structure“. In Large Meteorite Impacts III. Geological Society of America, 2005. http://dx.doi.org/10.1130/0-8137-2384-1.117.

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Mees, F., und G. Stoops. „Micromorphological Study of a Sediment Core from the Malha Crater Lake, Sudan“. In Soil Micro-Morphology: A Basic and Applied Science, Proceedings of the VIIIth International Working Meeting of Soil Micromorphology, 295–301. Elsevier, 1990. http://dx.doi.org/10.1016/s0166-2481(08)70341-6.

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Bischoff, Alan, Sverre Planke, Simon Holford und Andrew Nicol. „Seismic Geomorphology, Architecture and Stratigraphy of Volcanoes Buried in Sedimentary Basins“. In Updates in Volcanology - Transdisciplinary Nature of Volcano Science. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.95282.

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Our ability to investigate both the intrusive and extrusive parts of individual volcanoes has evolved with the increasing quality of seismic reflection datasets. Today, new seismic data and methods of seismic interpretation offer a unique opportunity to observe the entire architecture and stratigraphy of volcanic systems, with resolution down to tens of meters. This chapter summarises the methods used to extract the geomorphic aspects and spatio-temporal organisation of volcanic systems buried in sedimentary basins, with emphasis on the utility of 3D seismic reflection volumes. Based on descriptions and interpretations from key localities worldwide, we propose classification of buried volcanoes into three main geomorphic categories: (1) clusters of small-volume (<1 km3) craters and cones, (2) large (>5 km3) composite, shield and caldera volcanoes, and (3) voluminous lava fields (>10,000 km3). Our classification primarily describes the morphology, size and distribution of eruptive centres of buried volcanoes, and is independent of parameters such as the magma composition, tectonic setting, or eruption environment. The close correlation between the morphology of buried and modern volcanoes provides the basis for constructing realistic models for the facies distribution of igneous systems buried in sedimentary strata, establishing the principles for a new discipline of seismic-reflection volcanology.

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Singh, Yamuna. „Morphology of pseudosinkholes in granitic rocks of the Bastar Craton, Central India“. In Karst Geohazards, 67–72. Routledge, 2018. http://dx.doi.org/10.1201/9780203749708-9.

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Poag, C. Wylie, Deborah R. Hutchinson, Steven M. Colman und Myung W. Lee. „Seismic expression of the Chesapeake Bay impact crater: Structural and morphologic refinements based on new seismic data“. In Large meteorite impacts and planetary evolution; II. Geological Society of America, 1999. http://dx.doi.org/10.1130/0-8137-2339-6.149.

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Konferenzberichte zum Thema "Crater morphology"

Jiang, X. Y., Y. P. Wan, X. Y. Wang, H. Zhang, R. Goswami, H. Herman und S. Sampath. „Investigation of Splat/Substrate Contact During Molybdenum Thermal Spraying“. In ITSC 2000, herausgegeben von Christopher C. Berndt. ASM International, 2000. http://dx.doi.org/10.31399/asm.cp.itsc2000p0729.

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Abstract Molybdenum splats were produced at three plasma conditions on steel substrates preheated to three temperatures. Morphology of splats and corresponding craters formed on substrates were observed; dimensions of splats and craters were measured with an optical non-contact interferometer. It is found that substrate is significantly melted and deformed upon impact of the droplet, which leads to the formation of flower like splats and craters. On average, only about 36 to 53 % of the areas covered by splats were in good metallurgical/mechanical contact with substrate. Normalized crater volume increases with droplet size and the contact is improved for the high particle energy/high substrate temperature condition as compared with low particle energy/medium substrate energy condition. Splat morphology and crater formation is explained based on impinging jet heat transfer model.

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Mathew, Jose, Allesu K., Shravani Srisailam, K. P. Somashekhar, Prakash Naidu P. und P. S. Suvin. „Estimation of Residual Stresses and Crater Shape in µ-EDM by Finite Element Method“. In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-86100.

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Micro-Electric Discharge Machining (μ-EDM) is the process of machining electrically conductive materials in the form of micro-size craters by using precisely controlled sparks that occur between tool electrode and workpiece in the presence of dielectric fluid. The present paper attempts to predict the accurate model for thermal behavior of the EDM process on commercially available Inconel 718. The temperature gradients are crucial in identifying the zones of high temperature and high residual stresses. 3-Dimensional, transient coupled (structural and thermal) analysis is modeled for Inconel 718 workpiece material to estimate the residual stresses due to spark erosion and also to study the crater morphology. The residual stresses are higher at the centre of the crater and it is decreasing when move far from the centre. The simulated results are compared with the experimental results. Both the experimental and the simulated results are in good agreement.

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Mitchell, Antony J., David Hann und Kathy Simmons. „Experimental Investigation Into Crater Morphology for Droplets Impinging on a Moving Film“. In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-63443.

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The behaviour of impinging droplets is a field that has been studied for over 100 years mostly focused on impingements upon solid substrates or static films. Few studies report cases when the moving film might influence the impact outcomes. In many situations where droplet impact is industrially relevant there is film motion and relying on observations and correlations for impacts on static films might not be reliable. The University of Nottingham’s Gas Turbine and Transmissions Research Centre is conducting a research program investigating impact outcomes and crater morphology for water droplets of around 2–3 mm falling under the influence of gravity and impacting on films created by water flow down an inclined plane. In the investigation reported here dimensionless film heights were in the range 0.77 to 1.8 and the plane was inclined at 10° to the horizontal. This paper details the investigation into the morphology of the crater formed during an impingement event. The properties of the impinging droplet are measured using a high-speed camera to provide a side-view of the impingement. Brightness-Based Laser-Induced Fluorescence (BB-LIF) is used to provide three-dimensional measurements of the crater during the self-similar inertial regime. This is accomplished by doping the fluid with Rhodamine 6G, and exciting the fluorescence with a 527 nm pulsed Nd-Yag laser. A second high-speed camera observes the impingement from below in order to provide information about the behaviour of the film. The development of cavity depth is compared to published models from work on both deep and thin static films. Further, the development of cavity width with time is compared against existing models from static film research. A modification to these models is proposed that includes the effects of film velocity. The effect of film movement on the cavity footprint is examined; both the equivalent radius and the cavity width are investigated and the differences compared to static film experiments are quantified. Some modifications to an established width model are suggested, and an effect of droplet diameter upon this cavity width is noted. The work shows that static film models are not universally applicable for moving films.

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Bump, Vanessa J., und Leah M. Courtland. „INVESTIGATING SCORIA CONE MORPHOLOGY VIA GPR IMAGING IN CRATER FLAT VOLCANIC FIELD“. In GSA Annual Meeting in Indianapolis, Indiana, USA - 2018. Geological Society of America, 2018. http://dx.doi.org/10.1130/abs/2018am-321108.

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Pedrosa, Miriam M., Aylton Pagamisse und Erivaldo A. Silva. „Combination of bilateral filter and mathematical morphology to detect impact crater on mars surface“. In DINCON 2013 – Conferência Brasileira de Dinâmica, Controle e Aplicações. SBMAC, 2013. http://dx.doi.org/10.5540/03.2013.001.01.0153.

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Harris, David M., und Michael J. Yessik. „Contact pulsed Nd:YAG ablation of human dentin: fiber tip changes and crater morphology (SEM)“. In OE/LASE '94, herausgegeben von R. Rox Anderson. SPIE, 1994. http://dx.doi.org/10.1117/12.184926.

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Zhang, Xianzeng, Zhenlin Zhan, Shusen Xie und Qing Ye. „Crater Morphology and Thermal Injury of Bovine Shank Bone Ablated by Pulse CO2 Laser with Different Defocusing Conditions“. In 2009 Symposium on Photonics and Optoelectronics. IEEE eXpress Conference Publishing, 2009. http://dx.doi.org/10.1109/sopo.2009.5230126.

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Mitchell, Antony J., Kathy Simmons und David Hann. „Experimental Investigation Into Droplet Impingement Upon Moving Films Using High Speed Video and Thermal Imaging“. In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-51677.

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Aeroengine bearing chambers are geometrically complex, typically containing shafts, bearings, seals and stationary components. Oil is supplied for lubrication and cooling and so the chamber contains a highly rotating two-phase (oil/air) flow where the oil is typically present as droplets, ligaments, mist and films. These films may be thick or thin and film speed varies with chamber location. It is desirable to know a priori the outcome of a droplet-film impact event in terms of mass, momentum and energy transfer. There is a significant body of research on the interaction between droplets and static films. The experimental parameter space has been characterised on the basis of film thickness and impact parameter to predict the outcome of an impingement. The impingement of droplets on moving films has only begun to be investigated over the last decade and consequently models have not yet been developed and the parameter space has barely begun to be characterised. Within this paper results are presented from an experimental study in which water droplets of 3 mm and 3.8 mm at 20°C falling under the influence of gravity impinged onto water films flowing down an inclined plane. Film temperature was 30°C and film thicknesses were between 2.3 mm and 4.2 mm. High speed imaging was used to determine the impingement outcomes and cavity morphology. A high speed infrared camera was used to determine the extent of the thermally affected region and its temperature behaviour. We find that by using the resultant droplet velocity (combining droplet and film velocities) the film impingement outcomes can be characterised into regions very similar to those for static films. The data is presented as a function of splashing parameter and non-dimensional film thickness. It was observed that for these impacts on supercritical films (Fr > 1) there is less propensity for secondary droplet formation through jet breakup than on static and subcritical films (Fr < 1). Data was obtained for extent of the thermally affected region. It was found that the cooler droplet liquid spreads over the inside of the crater before heating up to film temperature. Development of crater shape and size was also studied and data compared to established models for droplet impact on deep static films. During the initial stages of an impact crater area increases similarly to that for static films although the crater shape itself is less similar and is asymmetrical due to the film motion.

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Kawai, Nobuaki, Mikio Nagano, Sunao Hasegawa und Eiichi Sato. „In-situ observation of damage evolution in polycarbonate subjected to hypervelocity impact“. In 2019 15th Hypervelocity Impact Symposium. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/hvis2019-011.

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Abstract In the fields of space engineering and planetary science, hypervelocity impact phenomena have been studied as they relate to the space debris problem and planetary impact. With regard to hypervelocity-impact-induced damage, many studies focus on the evaluation of impact-damage geometry and morphology, for example, to construct the ballistic limit equations and/or penetrating equations for space structures, and to predict the size and shape of crater and fragments generated by planetary impact [1-4]. While the final state or late stage of an impact event are of primal interest, damage accumulation at early stages affect the overall outcome of the impact event. The understanding of hypervelocity-impact-damage processes lead to improvement of material-response models for hypervelocity impact and higher fidelity simulations of hypervelocity impact events. Under such a background, we have performed real-time imaging of hypervelocity-impact events on transparent materials to investigate the impact-damage formation and evolution processes [5-7]. In our previous work, the stress-wave-propagation behavior and damage evolution were observed by means of a transmitted light shadowgraph. In these measurements, the shape of the longitudinal-stress-wave front, crater and spall fracture were successfully visualized. On the other hand, these shadowgraph images provide little information about damage microstructure. The shadowgraph has difficulty in visualizing ramped waves, such as the release wave, and also for the shear wave which is not accompanied by the change of volumetric strain. Those play important role in initiating damage. This occurs because the intensity of the shadowgraph image depends on the second spatial derivative of the refractive index. In this study, we try two types of real-time imaging of impact events. One is imaging by using scattered light on the impacted target to visualize the microstructure of the impact-induced damage, the other is a shadowgraph using polarized light to visualize propagation of the impact-induced stress field.

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Won, Hui Jun, Byambatseren Baigalmaa, Jei Kwon Moon, Chong Hun Jung und Kune Woo Lee. „Decontamination of Metal Surfaces Artificially Contaminated With Cs+ Ions by a Laser Ablation“. In 17th International Conference on Nuclear Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/icone17-75535.

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A Q-switched Nd:YAG laser with a 1064 nm and 450 mJ/pulse was employed to study the decontamination characteristics of Type 304 stainless steel specimens artificially contaminated with Cs+ ions. The specimens were treated with KCl and KNO3, respectively. The optimum number of laser shots for the system was determined at a given fluence of 57.3 J/cm2. The relative atomic molar ratio of a metal surface was determined by EPMA. For all the test specimens, more than 95% of the Cs+ ions were removed by the application of 42 laser shots. Cs+ ion removal efficiency could be improved by the addition of nitrate ions to the contaminated metal surface. A specimen treated with a KCl solution was more difficult to decontaminate in the experimental range. Before and after the laser irradiation, the morphology of the metal surfaces was investigated by SEM and XPS. Dusts generated during the laser irradiation were found to accumulate around a crater of the specimen treated with the KCl solution. By analyzing the XPS spectra of the KCl system, it was found that the ablated Cs+ ions formed an oxide in air. The higher decontamination efficiency of the KNO3 system could be attributed to the decomposition of the nitrate ions at a relatively low temperature and the easy reaction of the Cs+ ions with the oxygen generated from the decomposition of nitrate ions.

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