scholarly journals Rapid Tephra Identification in Geological Archives With Computed Tomography: Experimental Results and Natural Applications

2021 ◽  
Vol 8 ◽  
Author(s):  
Willem G. M. van der Bilt ◽  
Jan Magne Cederstrøm ◽  
Eivind W. N. Støren ◽  
Sarah M. P. Berben ◽  
Sunniva Rutledal
Keyword(s):  
Computed Tomography ◽  
Experimental Results ◽  
Great Promise ◽  
Sampling Strategies ◽  
Glass Shard ◽  
Volcanic Source ◽  
Custom Made ◽  
Laboratory Procedures ◽  
Basic Image ◽  
Micrometer Scale

Volcanic ash (tephra) horizons represent powerful chronological and stratigraphic markers: rapid and widespread deposition allows for correlation of geological records in time and space. Recent analytical advances enable identification of invisible ash (cryptotephra) up to thousands of kilometers from its volcanic source. This momentum has greatly expanded the reach and potential of tephrochronology: some deposits can now be traced across continents and oceans. However, the laborious laboratory procedures required to identify tephra horizons in geological archives hold back the pace of progress. By allowing the rapid visualization of ash at micrometer (µm) scales, computed tomography (CT) holds great promise to overcome these restrictions. In this study, we further demonstrate the potential of this tool for the tephra community with experimental results and applications on conventionally analyzed archives. A custom-made scanner helps us strike a balance between the convenience of whole-core medical scanners and the µm-resolution of micro-CT systems. Using basic image processing tools that can be readily mastered by tephrochronologists, we identified invisible horizons down to ∼500 shards in synthetic cores. In addition, procedures for the removal of image artifacts can be used to visualize other paleoenvironmental indicators such as bioturbation burrows, ice rafted debris or mineral dust. When applied on segments of manually counted natural archives, our approach captures cryptic glass shard maxima down to ∼300 shards/cm3. We also highlight the value of CT to help optimize sampling strategies by identifying micrometer-scale ash horizons that were not detected in shard count profiles. In conclusion, this work helps broaden the applicability of CT as a promising frontier in tephrochronology that can advance the field by optimizing the efficiency and accuracy of isochron detection.

Computed Tomography–Based Custom-Made Stem for Dysplastic Hips in Japanese Patients

2009 ◽  
Vol 24 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Kenji Kawate ◽  
Yutaka Ohneda ◽  
Tetsuji Ohmura ◽  
Hiroshi Yajima ◽  
Kazuya Sugimoto ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Japanese Patients ◽  
Custom Made

Design and Implementation of Spurs Detection System Based on OpenCV

2011 ◽  
Vol 345 ◽  
pp. 217-222
Author(s):  
Peng He ◽  
Lian Peng Wang ◽  
Na Wang ◽  
Gang Xu
Keyword(s):  
Computed Tomography ◽  
Embedded System ◽  
Detection System ◽  
Experimental Results ◽  
Design And Implementation ◽  
Function Expansion ◽  
The Embedded System ◽  
Improved Function ◽  
Small Bone ◽  
Improved Algorithm

In order to better solve the problem of detection of small bone spurs with convenient and accurate way, a portable spur detection system is designed. This system, in view of spur reproducibility characteristic, is characterized by the application for a kind of the improved algorithm based on the OpenCV. And it was successfully transplanted into the embedded system. The experimental results indicated that this system might precisely examine the small spur with difficulty discovery by naked eyes used fully by two images of computed tomography which done in different periods. The spur detection system needs to be further improved function to realize more applications. In fact, function expansion based on the system is easy to realize.

Segmentation of Kidneys from Computed Tomography Using 3D Fast GrowCut Algorithm

2013 ◽  
Vol 333-335 ◽  
pp. 1145-1150 ◽  
Author(s):  
Gao Yuan Dai ◽  
Zhi Cheng Li ◽  
Jia Gu ◽  
Lei Wang ◽  
Xing Min Li ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Three Dimensional ◽  
Experimental Results ◽  
Volume Data ◽  
Great Role ◽  
Color Features ◽  
Monotonically Decreasing Function ◽  
Kidney Segmentation ◽  
Ct Volume

This paper proposes a fast GrowCut (FGC) algorithm and applies the new algorithm in three-dimensional (3D)kidney segmentation from computed tomography (CT) volume data. Users could mark the object of interest with different labels in CT slices.FGC propagates the labels using monotonically decreasing function and color features to derive an optimal cut for a given data in space. The color features play a great role in comparing with neighborhood cells. The experimental results clearly demonstrate the superiority of FGC in accuracy and speed.

Visualization of microvasculature and thrombi by X-ray phase-contrast computed tomography in hepatocellular carcinoma

2016 ◽  
Vol 23 (2) ◽  
pp. 600-605 ◽  
Author(s):  
Jianbo Jian ◽  
Hao Yang ◽  
Xinyan Zhao ◽  
Ruijiao Xuan ◽  
Yujie Zhang ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Hepatocellular Carcinoma ◽  
Phase Contrast ◽  
Soft Tissues ◽  
Three Dimensional ◽  
X Ray ◽  
Density Distributions ◽  
Fine Structures ◽  
Tumor Growth And Metastasis ◽  
Micrometer Scale

Visualization of the microvascular network and thrombi in the microvasculature is a key step to evaluating the development of tumor growth and metastasis, and influences treatment selection. X-ray phase-contrast computed tomography (PCCT) is a new imaging technique that can detect minute changes of density and reveal soft tissues discrimination at micrometer-scale resolution. In this study, six human resected hepatocellular carcinoma (HCC) tissues were investigated with PCCT. A histological stain was added to estimate the accuracy of PCCT. The results showed that the fine structures of the microvasculature (measuring 30–100 µm) and thrombi in tiny blood vessels were displayed clearly on imaging the HCC tissues by PCCT. Moreover, density distributions of the thrombi were obtained, which could be reliably used to distinguish malignant from benign thrombi in HCC. In conclusion, PCCT can clearly show the three-dimensional subtle structures of HCC that cannot be detected by conventional absorption-based computed tomography and provides a new method for the imageology of HCC.

DEVELOPMENT AND IMPLEMENTATION OF A PORTABLE NUCLEONIC COMPUTED TOMOGRAPHY SYSTEM WITH CLAMP-ON-FEATURES FOR ENGINEERING INSPECTION

2015 ◽  
Vol 77 (17) ◽  
Author(s):  
Jaafar Abdullah ◽  
Hearie Hassan ◽  
Mohamad Rabaie Shari ◽  
Maslina Mohd Ibrahim ◽  
Nolida Yussup ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Gamma Ray ◽  
Bubble Column ◽  
Great Promise ◽  
Hydrodynamic Behavior ◽  
Tomographic Images ◽  
Tomography System ◽  
Set Up ◽  
System Configurations

The development and implementation of a portable nucleonic computed tomography system with clamp-on-features, called “GammaSpider”, employing gamma-ray for engineering inspection is briefly discussed. Depending on the object to be inspected, a small isotopic gamma-ray source, in combination of a NaI(Tl) scintillation detector and an autonomous mechanical gantry set-up are used. The basic theoretical aspects, the system configurations and the other features are presented. This system is capable of generating high quality tomographic images and thus, offers great promise for in-situ engineering inspection. It is successfully used to inspect blockages in pipelines, to examine wooden electric poles and to study hydrodynamic behavior of multiphase flow in a bubble column.  Some of the preliminary results are presented in this paper.

Effects of Production Methods on the Particle Morphology and Properties of Aqueous Au Nanofluids

2012 ◽  
Author(s):  
Ji-Hwan Lee ◽  
Seoung Youn Lee ◽  
Hyun Jin Kim ◽  
Seung-Hyun Lee ◽  
Seok Pil Jang ◽  
...  
Keyword(s):  
Particle Size ◽  
Chemical Reduction ◽  
Particle Morphology ◽  
Production Method ◽  
Reduction Reaction ◽  
Experimental Results ◽  
Production Methods ◽  
Transmission Electron ◽  
Custom Made ◽  
Dispersion State

In this study, the effects of nanofluid production methods on the particle morphology and properties of aqueous gold (Au) nanofluids are investigated using chemical reduction (referred as Turkevich method). Sonication method is used to provide energy for the production of Au nanofluids. Applied energy to the production of nanofluids and temperature of the reduction reaction are two main parameters in the production of aqueous Au nanofluids, affecting the particle size and dispersion state of Au nanofluids even though same production method is used. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) are used to characterize particle size, shape and distribution. The thermal conductivities of Au nanofluids are measured by the custom-made transient hot wire system. Uncertainty of the measurements is less than ±1.5%. The pH and electrical conductivities are also measured by commercial products in this study. Temperature range of measuring properties is 10–30 °C. Experimental results show that production methods can affect the particle morphology and transport properties of Au nanofluids. Sizes of produced Au nanoparticles are 20–40 nm depending on the production methods and parameters. Through characterization and experimental results of Au nanofluids, we found the optimum conditions for production of aqueous Au nanofluids which have high thermal conductivity, small particle size and well dispersed characteristics.

Ultrasound Computed Tomography in Breast Imaging: First Clinical Results of a Custom-Made Scanner

2010 ◽  
Vol 31 (06) ◽  
pp. 604-609 ◽  
Author(s):  
M. Hollenhorst ◽  
C. Hansen ◽  
N. Hüttebräuker ◽  
A. Schasse ◽  
L. Heuser ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Breast Imaging ◽  
Clinical Results ◽  
Ultrasound Computed Tomography ◽  
Custom Made

scholarly journals A network perspective reveals decreasing material diversity in studies on nanoparticle interactions with dissolved organic matter

2017 ◽  
Vol 114 (10) ◽  
pp. E1756-E1765 ◽  
Author(s):  
Nicole Sani-Kast ◽  
Jérôme Labille ◽  
Patrick Ollivier ◽  
Danielle Slomberg ◽  
Konrad Hungerbühler ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Engineered Nanoparticles ◽  
Experimental Results ◽  
Aquatic Environments ◽  
Particle Coating ◽  
Nanoparticle Interactions ◽  
Aliphatic Carbon ◽  
Extensive Body ◽  
Micrometer Scale

Dissolved organic matter (DOM) strongly influences the properties and fate of engineered nanoparticles (ENPs) in aquatic environments. There is an extensive body of experiments on interactions between DOM and ENPs and also larger particles. [We denote particles on the nano- and micrometer scale as particulate matter (PM).] However, the experimental results are very heterogeneous, and a general mechanistic understanding of DOM–PM interactions is still missing. In this situation, recent reviews have called to expand the range of DOM and ENPs studied. Therefore, our work focuses on the diversity of the DOM and PM types investigated. Because the experimental results reported in the literature are highly disparate and difficult to structure, a new format of organizing, visualizing, and interpreting the results is needed. To this end, we perform a network analysis of 951 experimental results on DOM–PM interactions, which enabled us to analyze and quantify the diversity of the materials investigated. The diversity of the DOM–PM combinations studied has mostly been decreasing over the last 25 y, which is driven by an increasing focus on several frequently investigated materials, such as DOM isolated from fresh water, DOM in whole-water samples, and TiO2and silver PM. Furthermore, there is an underrepresentation of studies into the effect of particle coating on PM–DOM interactions. Finally, it is of great importance that the properties of DOM used in experiments with PM, in particular the molecular weight and the content of aromatic and aliphatic carbon, are reported more comprehensively and systematically.

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