The pre-Late Wisconsin stratigraphy of southern Simcoe County, Ontario: implications for ice sheet buildup, decay, and Great Lakes drainage evolution

Recent three-dimensional mapping investigations in southern Simcoe County, Ontario, allow refinement of the existing regional stratigraphic framework. Analysis of 25 continuously cored boreholes has revealed a complex but consistent sediment succession that provides a record of the last two glacial cycles (Marine Isotope Stages 1–6). Five stratigraphic units (SU1–SU5) comprise the pre-Late Wisconsin record. The stratigraphy is floored by a presumed Illinoian glacial complex consisting of a lower, coarse-grained till (SU1), locally overlain by stratified glaciolacustrine and glaciofluvial sediments (SU2), but more commonly capped by a stone-poor, fine-grained till (SU3) of the Georgian Bay lobe. A widespread subaerial unconformity developed on the upper surface of SU3 contains organic-bearing, nonglacial deposits (SU4) ranging between 54 800 ± 3000 years BP (considered beyond the limits of radiocarbon dating) and 37 450 ± 590 14C years BP. SU4 is abruptly overlain by a thick succession of rhythmically laminated lacustrine muds graded upwards into glaciolacustrine silts and clays interrupted by regionally continuous sand bodies (SU5). The succession is capped (and locally truncated) by Late Wisconsin Newmarket Till. The sedimentary record of southern Simcoe County is correlated with other well-studied reference sections in southern Ontario and contains information that informs reconstructions of former ice extents in the lower Great Lakes region following the Illinoian glaciation. Several sediment units host aquifers, but limited thickness and spatial extent, as well as issues with naturally occurring dissolved gases and solids, restrict their use for groundwater supply.

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Symmetry-adapted digital modeling III. Coarse-grained icosahedral viruses

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s205327331600276x ◽

2016 ◽

Vol 72 (3) ◽

pp. 324-337 ◽

Cited By ~ 2

Author(s):

A. Janner

Keyword(s):

Lattice Point ◽

Three Dimensional ◽

Structural Data ◽

Data Bank ◽

Coarse Grained ◽

Large Set ◽

Fine Grained ◽

Coarse Grained Model ◽

Digital Modeling ◽

Icosahedral Viruses

Considered is the coarse-grained modeling of icosahedral viruses in terms of a three-dimensional lattice (the digital modeling lattice) selected among the projected points in space of a six-dimensional icosahedral lattice. Backbone atomic positions (Cα's for the residues of the capsid and phosphorus atoms P for the genome nucleotides) are then indexed by their nearest lattice point. This leads to a fine-grained lattice point characterization of the full viral chains in the backbone approximation (denoted as digital modeling). Coarse-grained models then follow by a proper selection of the indexed backbone positions, where for each chain one can choose the desired coarseness. This approach is applied to three viruses, the Satellite tobacco mosaic virus, the bacteriophage MS2 and the Pariacoto virus, on the basis of structural data from the Brookhaven Protein Data Bank. In each case the various stages of the procedure are illustrated for a given coarse-grained model and the corresponding indexed positions are listed. Alternative coarse-grained models have been derived and compared. Comments on related results and approaches, found among the very large set of publications in this field, conclude this article.

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Origins and engineering hazards of Swedish glaciomarine and marine clays

Geological Society London Engineering Geology Special Publications ◽

10.1144/gsl.eng.1991.007.01.24 ◽

1991 ◽

Vol 7 (1) ◽

pp. 257-264 ◽

Cited By ~ 4

Author(s):

R. L. Stevens ◽

M. S. Rosenbaum ◽

L. G. Hellgren

Keyword(s):

Urban Areas ◽

Urban Expansion ◽

Three Dimensional ◽

Depositional Environments ◽

Coarse Grained ◽

Land Uplift ◽

Fine Grained ◽

Depositional Settings ◽

Late Weichselian ◽

Three Dimensional Models

AbstractThis paper relates the Engineering features of fine-grained clays in the Göteborg area to their glacial sources, depositional settings and postdepositional changes. These deposits occupy valley and coastal areas where urban expansion has been concentrated, despite the considerable problems with settlement and quick-clay behaviour. Both mineralogical and permeability trends are largely determined by the textural characteristics of the deposits. The depositional environments, which have largely controlled the textural trends, are known to have evolved during late Weichselian times due to glacial retreat, isostatic land uplift and climatic changes. A generalized lithostratigraphical model has been produced and this is used here to help understand and predict the variability of the geotechnical properties. The stratigraphical trends in texture, mineralogy and structure are considered within four broad genetic categories: 1) coarse-grained glacial deposits, 2) glaciomarine deposits, 3) very distal glaciomarine deposits, and 4) shallow-marine deposits. These divisions can often be recognized within the logs of geotechnical reports, which suggested that they could provide the basis for development of three-dimensional models which have both geological and geotechnical predictive power within the vicinity of Göteborg. They could also act as a guide for the development of similar models in urban areas elsewhere.

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Harmonic Structure Design of Co-Cr-Mo Alloy with Outstanding Mechanical Properties

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.939.60 ◽

2014 ◽

Vol 939 ◽

pp. 60-67 ◽

Cited By ~ 3

Author(s):

Choncharoen Sawangrat ◽

Osamu Yamaguchi ◽

Sanjay Kumar Vajpai ◽

Kei Ameyama

Keyword(s):

Mechanical Properties ◽

Mechanical Milling ◽

Three Dimensional ◽

High Strength ◽

Surface Region ◽

Structure Design ◽

Coarse Grained ◽

Harmonic Structure ◽

Fine Grained ◽

Plasma Sintering

Co-Cr-Mo alloy powders were subjected to controlled mechanical milling at room temperature under Ar atmosphere to fabricate bimodal microstructure in the MM powders, having nanosized grains in the surface region and micron-sized coarse grains in the center of the milled powders. Subsequently, the MM powder was compacted by spark-plasma sintering (SPS) process. The sintered compacts indicated two structure areas: (i) ultra-fine grained (UFG) regions, called shell, and (ii) the coarse grained regions called core. The shell and the core correspond to the surface and center of the MM powders, respectively. The shell regions established a continuous three dimensional network of high strength ultra-fine grained regions, which surrounded the discrete coarse grained ductile regions. Such a microstructure is referred as Harmonic Structure. The sintered Co-Cr-Mo alloy compacts exhibited outstanding mechanical properties. The yield strength increased from 605 to 635 MPa, and ultimate tensile strength increased from 1201 to 1283 MPa. Moreover, the elongation was maintained more or less same as that of coarse grained compacts. Therefore, the harmonic structure design leads to the new generation microstructure of Co-Cr-Mo alloy, which demonstrates outstanding mechanical properties, i.e. superior strength and excellent ductility as compared to conventional materials. Keywords: mechanical milling, Co-Cr-Mo alloys, mechanical properties, harmonic structure.

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Alluvial architecture of fluvio-deltaic successions: a review with special reference to Holocene settings

Netherlands Journal of Geosciences – Geologie en Mijnbouw ◽

10.1017/s0016774600077817 ◽

2007 ◽

Vol 86 (3) ◽

pp. 211-227 ◽

Cited By ~ 13

Author(s):

M.J.P. Gouw

Keyword(s):

Special Reference ◽

Three Dimensional ◽

Coarse Grained ◽

Mississippi Valley ◽

Major Drawback ◽

Lower Mississippi Valley ◽

Fine Grained ◽

Base Level ◽

Alluvial Architecture ◽

Active Channels

AbstractAlluvial architecture has been subject of many studies because of the occurrence of natural resources in ancient fluvial successions. This paper provides an overview of the current state of research on alluvial architecture with special reference to Holocene fluvio-deltaic settings. Several examples from modern fluvio-deltaic areas, especially the Holocene Rhine-Meuse delta (the Netherlands) and the Lower Mississippi Valley (U.S.A.), are used to illustrate the architectural elements that can be distinguished in fluvial successions and to show the influence of the various controls on alluvial architecture (base level, climate, tectonism, aggradation, avulsion, and compaction). Avulsion is regarded as a principal process in the formation of fluvio-deltaic sequences, because it determines the location and number of active channels on the floodplain. The avulsion mechanism is still subject of debate, though. A brief description of the evolution of process-based alluvial-architecture models is given. These models simulate the proportion and distribution of coarse-grained channel belts in fine-grained overbank deposits. The major drawback of the present-day alluvial-architecture models is the lack of (three-dimensional) quantitative field data to test and validate them. The paper concludes with the suggestion to collect more architectural data from natural fluvial settings, to improve simulation of channel-belt geometry in alluvial-architecture models, and to implement new data and knowledge of fluvial processes into models.

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Quantitative grain-scale ferroic domain volume fractions and domain switching strains from three-dimensional X-ray diffraction data

Journal of Applied Crystallography ◽

10.1107/s1600576715007669 ◽

2015 ◽

Vol 48 (3) ◽

pp. 882-889 ◽

Cited By ~ 10

Author(s):

Jette Oddershede ◽

Marta Majkut ◽

Qinghua Cao ◽

Søren Schmidt ◽

Jonathan P. Wright ◽

...

Keyword(s):

Domain Switching ◽

Volume Fraction ◽

Three Dimensional ◽

Bulk Sample ◽

Coarse Grained ◽

X Ray Diffraction ◽

X Ray ◽

Volume Fractions ◽

Fine Grained ◽

Ferroic Materials

A method for the extension of the three-dimensional X-ray diffraction technique to allow the extraction of domain volume fractions in polycrystalline ferroic materials is presented. This method gives access to quantitative domain volume fractions of hundreds of independent embedded grains within a bulk sample. Such information is critical to furthering our understanding of the grain-scale interactions of ferroic domains and their influence on bulk properties. The method also provides a validation tool for mesoscopic ferroic domain modelling efforts. The mathematical formulations presented here are applied to tetragonal coarse-grained Ba0.88Ca0.12Zr0.06Ti0.94O3and rhombohedral fine-grained (0.82)Bi0.5Na0.5TiO3–(0.18)Bi0.5K0.5TiO3electroceramic materials. The fitted volume fraction information is used to calculate grain-scale non-180° ferroelectric domain switching strains. The absolute errors are found to be approximately 0.01 and 0.03% for the tetragonal and rhombohedral cases, which had maximum theoretical domain switching strains of 0.47 and 0.54%, respectively. Limitations and possible extensions of the technique are discussed.

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Correlation between dislocation, grain boundary and interface of duplex SS in stress corrosion cracking(SCC)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100177775 ◽

1990 ◽

Vol 48 (4) ◽

pp. 928-929

Author(s):

Wang Zheng-fang ◽

Z.F. Wang

Keyword(s):

Stainless Steel ◽

Thermal Cycle ◽

Secondary Phase ◽

Corrosion Cracking ◽

Coarse Grained ◽

Test Environment ◽

Fine Grained ◽

Evaluation Test ◽

Welding Thermal Cycle ◽

Micro Analysis

The main purpose of this study highlights on the evaluation of chloride SCC resistance of the material,duplex stainless steel,OOCr18Ni5Mo3Si2 (18-5Mo) and its welded coarse grained zone(CGZ).18-5Mo is a dual phases (A+F) stainless steel with yield strength:512N/mm2 .The proportion of secondary Phase(A phase) accounts for 30-35% of the total with fine grained and homogeneously distributed A and F phases(Fig.1).After being welded by a specific welding thermal cycle to the material,i.e. Tmax=1350°C and t8/5=20s,microstructure may change from fine grained morphology to coarse grained morphology and from homogeneously distributed of A phase to a concentration of A phase(Fig.2).Meanwhile,the proportion of A phase reduced from 35% to 5-10°o.For this reason it is known as welded coarse grained zone(CGZ).In association with difference of microstructure between base metal and welded CGZ,so chloride SCC resistance also differ from each other.Test procedures:Constant load tensile test(CLTT) were performed for recording Esce-t curve by which corrosion cracking growth can be described, tf,fractured time,can also be recorded by the test which is taken as a electrochemical behavior and mechanical property for SCC resistance evaluation. Test environment:143°C boiling 42%MgCl2 solution is used.Besides, micro analysis were conducted with light microscopy(LM),SEM,TEM,and Auger energy spectrum(AES) so as to reveal the correlation between the data generated by the CLTT results and micro analysis.

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