A new occurrence of corundum in eucrite and its significance

2020 ◽  
Vol 105 (11) ◽  
pp. 1656-1661
Author(s):  
Jie-Ya Li ◽  
Ai-Cheng Zhang ◽  
Naoya Sakamoto ◽  
Hisayoshi Yurimoto ◽  
Li-Xin Gu
Keyword(s):  
Internal Structure ◽  
Basaltic Magma ◽  
Three Dimensional ◽  
Mineral Inclusion ◽  
Northwest Africa ◽  
Poor Region ◽  
Internal Evolution

Abstract The diversity of lithologies is an important proxy of internal evolution in differentiated planets and asteroids. The major lithologies in Vesta, based on the howardite-eucrite-diogenite clan meteorites, include basalt, gabbro, noritic orthopyroxenite, orthopyroxenite, dunite, harzburgite, and dacite. No other lithology has been reported up to date. In this study, we report a new occurrence of corundum in eucrite meteorite Northwest Africa (NWA) 8647. Three-dimensional petrographic observations reveal that the corundum grain occurs as a mineral inclusion in a highly deformed pyroxene fragment. The texture indicates that the corundum is not a contaminant. The corundum-associated pyroxenes have Fe-Mn compositions consistent with typical pyroxenes from howardite-eucrite-diogenite meteorites. We suggest that the corundum grain could be a xenocryst incorporated during the ascent of a basaltic magma. The results might indicate the presence of an Al-rich, Si-poor region, probably lithology in the interior of Vesta, implying that the evolution and internal structure should be much more complex than previously thought.

X-ray microtomography

1988 ◽  
Vol 46 ◽  
pp. 998-999
Author(s):  
H.W. Deckman ◽  
B.F. Flannery ◽  
J.H. Dunsmuir ◽  
K.D' Amico
Keyword(s):  
Computed Tomography ◽  
Internal Structure ◽  
Imaging Technique ◽  
Three Dimensional ◽  
Tissue Structure ◽  
Individual Element ◽  
X Ray ◽  
Non Invasive ◽  
Panoramic Imaging ◽  
Three Dimensional Images

We have developed a new X-ray microscope which produces complete three dimensional images of samples. The microscope operates by performing X-ray tomography with unprecedented resolution. Tomography is a non-invasive imaging technique that creates maps of the internal structure of samples from measurement of the attenuation of penetrating radiation. As conventionally practiced in medical Computed Tomography (CT), radiologists produce maps of bone and tissue structure in several planar sections that reveal features with 1mm resolution and 1% contrast. Microtomography extends the capability of CT in several ways. First, the resolution which approaches one micron, is one thousand times higher than that of the medical CT. Second, our approach acquires and analyses the data in a panoramic imaging format that directly produces three-dimensional maps in a series of contiguous stacked planes. Typical maps available today consist of three hundred planar sections each containing 512x512 pixels. Finally, and perhaps of most import scientifically, microtomography using a synchrotron X-ray source, allows us to generate maps of individual element.

scholarly journals The Effect of Agarose on 3D Bioprinting

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 4028
Author(s):  
Chi Gong ◽  
Zhiyuan Kong ◽  
Xiaohong Wang
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Internal Structure ◽  
Three Dimensional ◽  
3D Bioprinting ◽  
Two Temperatures ◽  
Formed Structure ◽  
Accuracy And Stability ◽  
Physical Crosslinking ◽  
Complex Organ

In three-dimensional (3D) bioprinting, the accuracy, stability, and mechanical properties of the formed structure are very important to the overall composition and internal structure of the complex organ. In traditional 3D bioprinting, low-temperature gelatinization of gelatin is often used to construct complex tissues and organs. However, the hydrosol relies too much on the concentration of gelatin and has limited formation accuracy and stability. In this study, we take advantage of the physical crosslinking of agarose at 35–40 °C to replace the single pregelatinization effect of gelatin in 3D bioprinting, and printing composite gelatin/alginate/agarose hydrogels at two temperatures, i.e., 10 °C and 24 °C, respectively. After in-depth research, we find that the structures manufactured by the pregelatinization method of agarose are significantly more accurate, more stable, and harder than those pregelatined by gelatin. We believe that this research holds the potential to be widely used in the future organ manufacturing fields with high structural accuracy and stability.

scholarly journals Three-dimensional Imaging of Nanoscale Internal Structure by Coherent X-ray Diffraction Microscope

Materia Japan ◽  
2007 ◽  
Vol 46 (12) ◽  
pp. 827-827
Author(s):  
Yoshinori Nishino ◽  
Yukio Takahashi ◽  
Tetsuya Ishikawa ◽  
Eiichiro Matsubara
Keyword(s):  
Internal Structure ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Three Dimensional Imaging ◽  
X Ray

Multi-methodological three-dimensional investigation of a closed-system Pingo in Northwestern Canada

2021 ◽  
Author(s):  
Julius Kunz ◽  
Christof Kneisel
Keyword(s):  
Internal Structure ◽  
Closed System ◽  
Vegetation Type ◽  
Ice Core ◽  
Three Dimensional ◽  
Thermal Conditions ◽  
Surface Characteristics ◽  
Theoretical Models ◽  
Previous Theory ◽  
Vegetation Height

<p>The Mackenzie-Delta region is known for widespread permafrost and the association of different landforms, which are characteristic of a periglacial landscape development. Especially the density of closed-system pingos is nowhere on earth higher than in the area of the Tuktoyaktuk Peninsula. This type of pingos is common only in the continuous permafrost zone and is very sensitive to changing thermal conditions. In this study, we investigated the surface and subsurface conditions in the area of such a closed-system Pingo near Parsons Lake in the southern part of the Tuktoyaktuk Peninsula to study its internal structure and evolutional state. Therefore, we used a combined approach of electrical resistivity tomography (ERT), ground-penetrating radar (GPR) and manual frost probing. In addition, a high-resolution digital elevation model and an orthophoto were generated using in situ drone acquisitions. These enabled a detailed and areawide mapping of surface characteristics (e.g. vegetation height or type) and should contribute to the investigation of linkages between surface and subsurface characteristics.</p><p>Such a linkage could be observed comparing the mapped vegetation type and heights with active layer depths derived from manual frost probing and GPR measurements. Both parameters show a significant zonation in the area of the pingo and its surrounding. In addition, the results of the quasi three-dimensional ERT measurements could deliver new insights into the three-dimensional internal structure of the pingo and a massive ice core could be detected. However, the shape as well as the position of the massive ice core in relation to the elevated surface of the pingo differ from the previous theory of closed-system pingo formation and therefore raises some questions. Also the existence of a talik could be confirmed, but its position beside the ice core within the eastern flank of the pingo and not below the massive ice core also differs from the theoretical models and should be discussed.</p>

scholarly journals Evaluation of the 3D Printing Accuracy of a Dental Model According to Its Internal Structure and Cross-Arch Plate Design: An In Vitro Study

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5433
Author(s):  
Seung-Ho Shin ◽  
Jung-Hwa Lim ◽  
You-Jung Kang ◽  
Jee-Hwan Kim ◽  
June-Sung Shim ◽  
...  
Keyword(s):  
3D Printing ◽  
Internal Structure ◽  
Three Dimensional ◽  
In Vitro Study ◽  
Thick Shell ◽  
Plate Design ◽  
Dental Model ◽  
3D Printed ◽  
Modeling Data

The amount of photopolymer material consumed during the three-dimensional (3D) printing of a dental model varies with the volume and internal structure of the modeling data. This study analyzed how the internal structure and the presence of a cross-arch plate influence the accuracy of a 3D printed dental model. The model was designed with a U-shaped arch and the palate removed (Group U) or a cross-arch plate attached to the palate area (Group P), and the internal structure was divided into five types. The trueness and precision were analyzed for accuracy comparisons of the 3D printed models. Two-way ANOVA of the trueness revealed that the accuracy was 135.2 ± 26.3 µm (mean ± SD) in Group U and 85.6 ± 13.1 µm in Group P. Regarding the internal structure, the accuracy was 143.1 ± 46.8 µm in the 1.5 mm-thick shell group, which improved to 111.1 ± 31.9 µm and 106.7 ± 26.3 µm in the roughly filled and fully filled models, respectively. The precision was 70.3 ± 19.1 µm in Group U and 65.0 ± 8.8 µm in Group P. The results of this study suggest that a cross-arch plate is necessary for the accurate production of a model using 3D printing regardless of its internal structure. In Group U, the error during the printing process was higher for the hollowed models.

FIB-SEM: An Additional Technique for Investigating Internal Structure of Pollen Walls

2013 ◽  
Vol 19 (6) ◽  
pp. 1535-1541 ◽  
Author(s):  
Alisoun House ◽  
Kevin Balkwill
Keyword(s):  
Electron Microscopy ◽  
Internal Structure ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Three Dimensional ◽  
Pollen Grains ◽  
Grain Morphology ◽  
Pollen Grain ◽  
Pollen Wall ◽  
Scanning Electron

AbstractPollen grain morphology has been widely used in the classification of the Acanthaceae, where external pollen wall features have proved useful in determining relationships between taxa. Although detailed information has been accumulated using light microscopy, transmission electron microscopy and scanning electron microscopy (SEM) techniques, internal pollen wall features lack investigation and the techniques are cumbersome. A new technique involving precise cross sectioning or slicing of pollen grains at a selected position for examining wall ultrastructure, using a focused ion beam-scanning electron microscope (FIB-SEM), has been explored and promising results have been obtained. The FIB-SEM offers a good technique for reliable, high resolution, three-dimensional (3D) viewing of the internal structure of the pollen grain wall.

Development of a 3-Dimensional Internal Structure Microscope (3D-ISM) for the Observation to Biological Organisms.

1997 ◽  
Vol 3 (S2) ◽  
pp. 243-244 ◽  
Author(s):  
Hideo Yokota ◽  
Ken-ichi Kudoh ◽  
Kahei Sato ◽  
Toshiro Higuchi
Keyword(s):  
Internal Structure ◽  
Color Image ◽  
Block Diagram ◽  
Three Dimensional ◽  
Image Data ◽  
3 Dimensional ◽  
True Color Image ◽  
Sample Position ◽  
Type 3 ◽  
Biological Organisms

We developed a new type 3-Dimensional Internal Structure Microscope (3D-ISM) for the observation of internal structures of samples. The internal structure of a sample is obtained by cutting it into thin slices and observing the cutting side continuously while cutting. The position of the camera, as well as the sample position are fixed. Therefore there is no shift between the sections, and this system can obtain a true color image of the sample, which is a high resolution and a high-quality three-dimensional image compared with X-ray CT and MRI. After repeatedly slicing a sample, the digital image data from the sectional views is transferred to a computer, where 3-dimensional images of the internal structure of the sample are reconstructed. Using this system we analyzed many biological organisms. In this paper, a mouse specimen has been cut and the 3-dimensional images are shown.This article presents the outline of the device and the principle of the observation. FIG.l shows a corresponding block diagram and Fig. 2 a schematic view of the 3D-ISM.

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