Application of end‐member modelling to grain‐size data: Constraints and limitations

Grain refinement is a critical technology for the successful production of cast parts; whether that be preforms such as extrusion billet or rolling slab, or near net-shape castings. A refined microstructure has many advantages with reduced defects and improved mechanical properties. This article describes the approaches to the prediction of grain size in Al-alloys refined by Al-Ti-B master alloys. Included are empirical approaches based on the generation and analysis of grain size data, the development of analytical equations, and the use of finite element approaches to the prediction of grain sizes. It is clear that researchers have a good ability to predict grain size of Al-alloys grain refined by Al-Ti-B master alloys, although there are still some outstanding challenges, particularly in considering more extreme solidification conditions and poisoning of the master alloys.

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Sedimentary environment prediction of grain-size data based on machine learning approach

Interpretation ◽

10.1190/int-2019-0153.1 ◽

2020 ◽

Vol 8 (3) ◽

pp. SL71-SL78

Author(s):

Qiao Su ◽

Yanhui Zhu ◽

Fang Hu ◽

Xingyong Xu

Keyword(s):

Machine Learning ◽

Grain Size ◽

Prediction Model ◽

Sedimentary Environment ◽

Machine Learning Algorithms ◽

Grain Size Analysis ◽

Size Analysis ◽

Data Set ◽

Sedimentary Environments ◽

Size Data

Grain size is one of the most important records for sedimentary environment, and researchers have made remarkable progress in the interpretation of sedimentary environments by grain size analysis in the past few decades. However, these advances often depend on the personal experience of the scholars and combination with other methods used together. Here, we constructed a prediction model using the K-nearest neighbors algorithm, one of the machine learning methods, which can predict the sedimentary environments of one core through a known core. Compared to the results of other studies based on the comprehensive data set of grain size and four other indicators, this model achieved a high precision value only using the grain size data. We have also compared our prediction model with other mainstream machine learning algorithms, and the experimental results of six evaluation metrics shed light on that this prediction model can achieve the higher precision. The main errors of the model reflect the length of the conversation area of sedimentary environment, which is controlled by the sedimentary dynamics. This model can provide a quick comparison method of the cores in a similar environment; thus, it may point out the preliminary guidance for further study.

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A basic end-member model algorithm for grain-size data of marine sediments

Estuarine Coastal and Shelf Science ◽

10.1016/j.ecss.2020.106656 ◽

2020 ◽

Vol 236 ◽

pp. 106656 ◽

Cited By ~ 1

Author(s):

Xiaodong Zhang ◽

Hongmin Wang ◽

Shumei Xu ◽

Zuosheng Yang

Keyword(s):

Grain Size ◽

Marine Sediments ◽

Member Model ◽

Model Algorithm ◽

Size Data ◽

End Member Model

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Glacio-eustatic variability in the sedimentation pattern over northern Japan during the past 600 ka

10.5194/egusphere-egu2020-748 ◽

2020 ◽

Author(s):

Sushree Sova Barik ◽

Raj K. Singh ◽

Pratik K. Upadhyaya ◽

Lisantaraj Biswal ◽

Nishant Vats ◽

...

Keyword(s):

Grain Size ◽

Energy Condition ◽

Ice Sheets ◽

Japan Sea ◽

Mineral Analysis ◽

Sedimentation Pattern ◽

The Past ◽

The Japan Sea ◽

Size Data ◽

Northern Japan

<p>The Japan Sea is a semi-enclosed marginal sea affected by global sea-level fluctuation, expansion of seasonal and permanent sea-ice cover, having a significant influence on the regional climate neighboring Japan Sea. Middle Pleistocene to Holocene sediments of the Integrated Ocean Drilling Program site U1423 situated in the northeastern part of Japan Sea was processed for the grain size analysis, semi-quantitative mineral analysis, and clay mineral analysis to access glacio-eustatic control on sedimentation pattern over Japan Sea during the past 610 ka. The average time resolution per sample is ~10 kyr. The mean grain size data suggest the dominance of silt size fraction over the sand and clay. The end member modeling of grain size data suggests the presence of two different energy conditions that varied with the time and influenced by the glacio-eustatic changes over the Japan Sea. The grain size data are relatively coarser and deposited in the higher energy condition during the glacial periods in comparison to interglacial periods except for MIS 2, 4, and 8. The higher energy condition during the glacial intervals suggesting deposition of grains due to the melting of seasonal/permanent ice sheets in the northern Japan Sea. The eolian dust brought from the Chinese loess deposits are relative finer in size and dominated by a higher proportion of quartz. During the glacial phases, illite and kaolinite (%) show a decreasing trend than the interglacial phases suggesting less terrigenous input. The high illite and decreased smectite (%) during interglacial phases suggest a higher degree of physical weathering. The significant increase in the smectite/(illite+chlorite) ratio suggests a higher degree of chemical weathering of the nearby source area, which varied over time. The overall study suggests the phase-wise variability in the presence of permanent/seasonal ice sheets and East Aian Winter Monsoon strength during the past 600 ka.</p>

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A synchronous change of mid- to late- Holocene hydroclimate and prehistoric population in coastal East Asia indicated by pollen, XRF and grain size data

10.5194/egusphere-egu2020-9276 ◽

2020 ◽

Author(s):

Jinheum Park ◽

Jungjae Park ◽

Sangheon Yi ◽

Jin Cheul Kim ◽

Eunmi Lee ◽

...

Keyword(s):

Grain Size ◽

Pacific Ocean ◽

Korean Peninsula ◽

Late Holocene ◽

Southern Oscillation ◽

Precipitation Amount ◽

Equatorial Pacific ◽

Equatorial Pacific Ocean ◽

The Core ◽

Size Data

<p>A relationship between climate change and prehistoric civilizations is a topic of growing interest. Here, we present a 6,000-year-long pollen, X-ray fluorescence (XRF), and grain size data of the core STP18-03 from the southern Korean peninsula, spanning the mid- to late- Holocene. The proxies generally show a synchronous change throughout the core. During dry periods, reduced precipitation indicated by lower sand proportion (river discharge) would have hindered tree growth, which then resulted in increased titanium erosion from nearby hills, and vice versa. The drying trend is remarkable during ca. 4.8, 4.3, 4.0, 3.3, 2.7-2.3 ka BP and corresponds with sudden dropping points of a summed probability distribution (SPD) of archaeological records found in the Korean Peninsula. This implies that ancient civilizations of Korea responded highly sensitively to abrupt climate deterioration. As an underlying mechanism of the change, we suggest a role of the equatorial Pacific Ocean. The temporal pattern of our arboreal pollen proportion closely follows that of sea surface temperature (SST) data from the Western Pacific Warm Pool (WPWP) region. Furthermore, the dry periods indicated by our multiple proxies coincide with strong El Ni&#241;o&#8211;Southern Oscillation (ENSO) activity, when the core region of the warm seawater pool deviated eastward than usual. This supports that the equatorial Pacific Ocean has served as an important factor for modulating mid- to late- Holocene hydroclimate of the Korean Peninsula, where the East Asian Summer Monsoon (EASM) accounts for nearly 70 percent of the total annual precipitation amount.</p>

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Multivariate statistic and time series analyses of grain-size data in quaternary sediments of Lake El'gygytgyn, NE Russia

Climate of the Past ◽

10.5194/cp-9-2459-2013 ◽

2013 ◽

Vol 9 (6) ◽

pp. 2459-2470 ◽

Cited By ~ 17

Author(s):

A. Francke ◽

V. Wennrich ◽

M. Sauerbrey ◽

O. Juschus ◽

M. Melles ◽

...

Keyword(s):

Time Series ◽

Grain Size ◽

Far East ◽

Principal Component ◽

Sediment Supply ◽

Multivariate Statistic ◽

Lake El’Gygytgyn ◽

Lake Center ◽

The Impact ◽

Size Data

Abstract. Lake El'gygytgyn, located in the Far East Russian Arctic, was formed by a meteorite impact about 3.58 Ma ago. In 2009, the International Continental Scientific Drilling Program (ICDP) at Lake El'gygytgyn obtained a continuous sediment sequence of the lacustrine deposits and the upper part of the impact breccia. Here, we present grain-size data of the past 2.6 Ma. General downcore grain-size variations yield coarser sediments during warm periods and finer ones during cold periods. According to principal component analysis (PCA), the climate-dependent variations in grain-size distributions mainly occur in the coarse silt and very fine silt fraction. During interglacial periods, accumulation of coarser material in the lake center is caused by redistribution of clastic material by a wind-induced current pattern during the ice-free period. Sediment supply to the lake is triggered by the thickness of the active layer in the catchment and the availability of water as a transport medium. During glacial periods, sedimentation at Lake El'gygytgyn is hampered by the occurrence of a perennial ice cover, with sedimentation being restricted to seasonal moats and vertical conduits through the ice. Thus, the summer temperature predominantly triggers transport of coarse material into the lake center. Time series analysis that was carried out to gain insight into the frequency of the grain-size data showed variations predominately on 98.5, 40.6, and 22.9 kyr oscillations, which correspond to Milankovitch's eccentricity, obliquity and precession bands. Variations in the relative power of these three oscillation bands during the Quaternary suggest that sedimentation processes at Lake El'gygytgyn are dominated by environmental variations caused by global glacial–interglacial variations (eccentricity, obliquity), and local insolation forcing and/or latitudinal teleconnections (precession), respectively.

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Estimation of Hydraulic Conductivity and Its Uncertainty from Grain-Size Data Using GLUE and Artificial Neural Networks

Mathematical Geosciences ◽

10.1007/s11004-012-9409-2 ◽

2012 ◽

Vol 44 (6) ◽

pp. 739-763 ◽

Cited By ~ 25

Author(s):

Bart Rogiers ◽

Dirk Mallants ◽

Okke Batelaan ◽

Matej Gedeon ◽

Marijke Huysmans ◽

...

Keyword(s):

Neural Networks ◽

Grain Size ◽

Artificial Neural Networks ◽

Hydraulic Conductivity ◽

Artificial Neural ◽

Size Data

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Dielectric, Pyroelectric, and Thermal Properties of Solid Solutions of Ba (Ti,Zr)O3,Ba(Ti,Hf)03, Ba(Ti,Sn) 03 and (Ba,Nd)TiO3

MRS Proceedings ◽

10.1557/proc-360-127 ◽

1994 ◽

Vol 360 ◽

Cited By ~ 5

Author(s):

K. K. Deb

Keyword(s):

Grain Size ◽

Pyroelectric Coefficient ◽

Dielectric Constants ◽

Dielectric Losses ◽

Oxide Ceramics ◽

Infrared Sensors ◽

Pzt Thin Films ◽

Detector Arrays ◽

Property Modification ◽

Size Data

AbstractModified BaTiO3 ceramics are candidate materials for infrared sensors in nightvision equipment. Measurements of dielectric constants, dielectric losses, pyroelectric coefficient, and heat capacities as functions of temperature and frequency are performed. Crystallographic and grain size data are also presented. It is shown that additions of these impurities to BaTiO3 alters the temperature of phase transformations and, with it, dielectric and pyroelectric properties. The results of these measurements were compared with those of PZT and PbTiO3 ceramics, which are currently the favoredmaterials for uncooled detector arrays, as well as PbTiO3 and PZT thin films. It is concluded that these oxide ceramics offer the combination of preparative ease of property modification and show good performance at low impurity concentrations.

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