scholarly journals High-resolution Characterization of Quartzites in Sourcing Analysis: Intra-Outcrop Variability at Naibor Soit, Tanzania

2019 ◽  
Author(s):  
Maria Soto ◽  
Julien Favreau ◽  
Tristan Carter ◽  
Paul R. Durkin ◽  
Stephen Hubbard ◽  
...  
Keyword(s):  
High Resolution ◽  
Raw Materials ◽  
Predictive Values ◽  
High Resolution Data ◽  
Mineral Assemblages ◽  
Characterization Studies ◽  
The Common ◽  
Resource Variability ◽  
Palaeolithic Archaeology

Despite the common exploitation of quartzites as raw materials during the African Stone Age, petrographic and geochemical characterization studies are scarce in Palaeolithic archaeology. Naibor Soit outcrop in Oldupai Gorge (Tanzania), considered the main source for lithic procurement in the area, probably represents the exception to this analytical scarcity. Previous analysis determined resource variability and the existence of singular mineral assemblages and geochemical compositions.This study present the first systematic survey and EDXRF characterization of 86 samples from the two inselbergs conforming Naibor Soit. Samples are associated to nine macroscopic varieties and mineralogically composed by quartz, muscovite, occasional hematite, rutile and fuchsite. Geochemical analysis, compared also with the available data, confirm the existence of inter-/ intra-outcrop variability and suggest compositional similarities among some areas of both inselbergs.This paper proportionate high-resolution data and elevated predictive values for future archaeological sourcing studies in the area. Results emphasized in the necessity of systematic surveys and sampling to fully understand raw materials variability and the factors determining selection and exploitation as part of palaeocological behaviours.

scholarly journals Object-Based Analysis Using Unmanned Aerial Vehicles (UAVs) for Site-Specific Landslide Assessment

2020 ◽  
Vol 12 (11) ◽  
pp. 1711 ◽  
Author(s):  
Efstratios Karantanellis ◽  
Vassilis Marinos ◽  
Emmanuel Vassilakis ◽  
Basile Christaras
Keyword(s):  
High Resolution ◽  
Unmanned Aerial Vehicles ◽  
Low Cost ◽  
Mass Movement ◽  
Terrain Analysis ◽  
Site Specific ◽  
High Resolution Data ◽  
Aerial Vehicles ◽  
Object Based

The increased development of computer vision technology combined with the increased availability of innovative platforms with ultra-high-resolution sensors, has generated new opportunities and fields for investigation in the engineering geology domain in general and landslide identification and characterization in particular. During the last decade, the so-called Unmanned Aerial Vehicles (UAVs) have been evaluated for diverse applications such as 3D terrain analysis, slope stability, mass movement hazard and risk management. Their advantages of detailed data acquisition at a low cost and effective performance identifies them as leading platforms for site-specific 3D modelling. In this study, the proposed methodology has been developed based on Object-Based Image Analysis (OBIA) and fusion of multivariate data resulted from UAV photogrammetry processing in order to take full advantage of the produced data. Two landslide case studies within the territory of Greece, with different geological and geomorphological characteristics, have been investigated in order to assess the developed landslide detection and characterization algorithm performance in distinct scenarios. The methodology outputs demonstrate the potential for an accurate characterization of individual landslide objects within this natural process based on ultra high-resolution data from close range photogrammetry and OBIA techniques for landslide conceptualization. This proposed study shows that UAV-based landslide modelling on the specific case sites provides a detailed characterization of local scale events in an automated sense with high adaptability on the specific case site.

Peroneal neuropathy after weight loss: a high-resolution ultrasonographic characterization of the common peroneal nerve

2011 ◽  
Vol 40 (12) ◽  
pp. 1557-1562 ◽  
Author(s):  
Liesbeth Meylaerts ◽  
Eline Cardinaels ◽  
Jan Vandevenne ◽  
Beatrijs Velghe ◽  
Geert Gelin ◽  
...  
Keyword(s):  
Weight Loss ◽  
High Resolution ◽  
Peroneal Nerve ◽  
Common Peroneal Nerve ◽  
Peroneal Neuropathy ◽  
The Common

EBSD-Based Dislocation Microscopy

2010 ◽  
Vol 160 ◽  
pp. 3-10 ◽  
Author(s):  
Brent L. Adams ◽  
Calvin J. Gardner ◽  
David T. Fullwood
Keyword(s):  
High Resolution ◽  
Electron Backscatter Diffraction ◽  
High Resolution Data ◽  
Geometrically Necessary Dislocation ◽  
Resolution Electron ◽  
Electron Backscatter ◽  
Single Grain ◽  
Backscatter Diffraction ◽  
The Continuum

Recent advances in high-resolution electron backscatter diffraction (EBSD)-based microscopy are applied to the characterization of incompatibility structures near the grain boundaries (GBs) in polycrystals. The principal interest described here is recovery of geometrically-necessary dislocation (density) tensors, of the 2- and 3-D type, described by Nye and Kröner. These developments are presented in the context of the continuum dislocation theory. High resolution data obtained near a single grain boundary in well-annealed, low content steel suggests that it may be possible to measure the intrinsic elastic properties of GBs.

Characterization of the wave resource variability in the French Basque coastal area based on a high-resolution hindcast

2021 ◽  
Author(s):  
Matthias Delpey ◽  
Ximun Lastiri ◽  
Stéphane Abadie ◽  
Volker Roeber ◽  
Philippe Maron ◽  
...  
Keyword(s):  
High Resolution ◽  
Coastal Area ◽  
Resource Variability

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

High-resolution electron microscopy of nanostructured materials

1995 ◽  
Vol 53 ◽  
pp. 172-173
Author(s):  
M. José-Yacamán
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Grain Boundaries ◽  
Nanostructured Materials ◽  
High Resolution Electron Microscopy ◽  
Hrem Image ◽  
Small Particles ◽  
Resolution Electron ◽  
Nanophase Materials

Electron microscopy is a fundamental tool in materials characterization. In the case of nanostructured materials we are looking for features with a size in the nanometer range. Therefore often the conventional TEM techniques are not enough for characterization of nanophases. High Resolution Electron Microscopy (HREM), is a key technique in order to characterize those materials with a resolution of ~ 1.7A. High resolution studies of metallic nanostructured materials has been also reported in the literature. It is concluded that boundaries in nanophase materials are similar in structure to the regular grain boundaries. That work therefore did not confirm the early hipothesis on the field that grain boundaries in nanostructured materials have a special behavior. We will show in this paper that by a combination of HREM image processing, and image calculations, it is possible to prove that small particles and coalesced grains have a significant surface roughness, as well as large internal strain.

High-resolution transmission electron microscopic study of highly oxygen doped silicon layer

1989 ◽  
Vol 47 ◽  
pp. 692-693
Author(s):  
H. Takaoka ◽  
M. Tomita ◽  
T. Hayashi
Keyword(s):  
High Resolution ◽  
Oxygen Concentration ◽  
Silicon Layer ◽  
Detailed Structure ◽  
Electron Microscopic ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Doped Silicon ◽  
Argon Ion

High resolution transmission electron microscopy (HRTEM) is the effective technique for characterization of detailed structure of semiconductor materials. Oxygen is one of the important impurities in semiconductors. Detailed structure of highly oxygen doped silicon has not clearly investigated yet. This report describes detailed structure of highly oxygen doped silicon observed by HRTEM. Both samples prepared by Molecular beam epitaxy (MBE) and ion implantation were observed to investigate effects of oxygen concentration and doping methods to the crystal structure.The observed oxygen doped samples were prepared by MBE method in oxygen environment on (111) substrates. Oxygen concentration was about 1021 atoms/cm3. Another sample was silicon of (100) orientation implanted with oxygen ions at an energy of 180 keV. Oxygen concentration of this sample was about 1020 atoms/cm3 Cross-sectional specimens of (011) orientation were prepared by argon ion thinning and were observed by TEM at an accelerating voltage of 400 kV.

HRTEM simulation of interfacial structure in amorphous multilayers

1989 ◽  
Vol 47 ◽  
pp. 466-467
Author(s):  
Margaret L. Sattler ◽  
Michael A. O'Keefe
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Cross Section ◽  
High Resolution Electron Microscopy ◽  
Interfacial Structure ◽  
Multilayer Sample ◽  
Resolution Electron ◽  
Multilayered Materials ◽  
Simulated Images

Multilayered materials have been fabricated with such high perfection that individual layers having two atoms deep are possible. Characterization of the interfaces between these multilayers is achieved by high resolution electron microscopy and Figure 1a shows the cross-section of one type of multilayer. The production of such an image with atomically smooth interfaces depends upon certain factors which are not always reliable. For example, diffusion at the interface may produce complex interlayers which are important to the properties of the multilayers but which are difficult to observe. Similarly, anomalous conditions of imaging or of fabrication may occur which produce images having similar traits as the diffusion case above, e.g., imaging on a tilted/bent multilayer sample (Figure 1b) or deposition upon an unaligned substrate (Figure 1c). It is the purpose of this study to simulate the image of the perfect multilayer interface and to compare with simulated images having these anomalies.

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