Crystallography of three-dimensional fluid flows with chirality in hexagonal cases

2019 ◽  
Vol 75 (6) ◽  
pp. 798-813 ◽  
Author(s):  
Takahiro Nishiyama
Keyword(s):  
Plasma Physics ◽  
Materials Science ◽  
Invariant Tori ◽  
Three Dimensional ◽  
Fluid Flows ◽  
Physics First ◽  
Free Fields ◽  
Zero Points

Magnetic groups are applied to three-dimensional fluid flows with chirality, which are called Beltrami flows (or force-free fields in plasma physics). First, six Beltrami flows are derived so that their symmetries and antisymmetries are described by six different hexagonal magnetic groups. The general Wyckoff positions are used to derive the flows. Special Wyckoff positions are shown to be useful for finding the zero points of the flows. Tube-like surfaces called invariant tori are observed to interlace and form various crystal-like structures when streamlines winding around the surfaces are numerically plotted. Next, two simpler hexagonal Beltrami flows are derived, and their zero points and invariant tori are studied. Some families of the invariant tori have arrangements similar to those observed in materials science.

Visualizing Fluid Flows With X-Rays

2007 ◽  
Author(s):  
Theodore J. Heindel ◽  
Terrence C. Jensen ◽  
Joseph N. Gray
Keyword(s):  
Computed Tomography ◽  
Flow Visualization ◽  
Three Dimensional ◽  
Fluid Flows ◽  
X Rays ◽  
Radiographic Images ◽  
Optical Access ◽  
X Ray ◽  
X Ray Computed ◽  
Density Map

There are several methods available to visualize fluid flows when one has optical access. However, when optical access is limited to near the boundaries or not available at all, alternative visualization methods are required. This paper will describe flow visualization using an X-ray system that is capable of digital X-ray radiography, digital X-ray stereography, and digital X-ray computed tomography (CT). The unique X-ray flow visualization facility will be briefly described, and then flow visualization of various systems will be shown. Radiographs provide a two-dimensional density map of a three dimensional process or object. Radiographic images of various multiphase flows will be presented. When two X-ray sources and detectors simultaneously acquire images of the same process or object from different orientations, stereographic imaging can be completed; this type of imaging will be demonstrated by trickling water through packed columns and by absorbing water in a porous medium. Finally, local time-averaged phase distributions can be determined from X-ray computed tomography (CT) imaging, and this will be shown by comparing CT images from two different gas-liquid sparged columns.

scholarly journals Cloud Manufacturing, Internet of Things-Assisted Manufacturing and 3D Printing Technology: Reliable Tools for Sustainable Construction

2021 ◽  
Vol 13 (13) ◽  
pp. 7327
Author(s):  
Rajesh Singh ◽  
Anita Gehlot ◽  
Shaik Vaseem Akram ◽  
Lovi Raj Gupta ◽  
Manoj Kumar Jena ◽  
...  
Keyword(s):  
3D Printing ◽  
Internet Of Things ◽  
Materials Science ◽  
Predictive Analytics ◽  
Residential Buildings ◽  
Three Dimensional ◽  
Cloud Manufacturing ◽  
Service Evaluation ◽  
Sustainable Construction ◽  
Access Technology

The United Nations (UN) 2030 agenda on sustainable development goals (SDGs) encourages us to implement sustainable infrastructure and services for confronting challenges such as large energy consumption, solid waste generation, depletion of water resources and emission of greenhouse gases in the construction industry. Therefore, to overcome challenges and establishing sustainable construction, there is a requirement to integrate information technology with innovative manufacturing processes and materials science. Moreover, the wide implementation of three-dimensional printing (3DP) technology in constructing monuments, artistic objects, and residential buildings has gained attention. The integration of the Internet of Things (IoT), cloud manufacturing (CM), and 3DP allows us to digitalize the construction for providing reliable and digitalized features to the users. In this review article, we discuss the opportunities and challenges of implementing the IoT, CM, and 3D printing (3DP) technologies in building constructions for achieving sustainability. The recent convergence research of cloud development and 3D printing (3DP) are being explored in the article by categorizing them into multiple sections including 3D printing resource access technology, 3D printing cloud platform (3D–PCP) service architectures, 3D printing service optimized configuration technology, 3D printing service evaluation technology, and 3D service control and monitoring technology. This paper also examines and analyzes the limitations of existing research and, moreover, the article provides key recommendations such as automation with robotics, predictive analytics in 3DP, eco-friendly 3DP, and 5G technology-based IoT-based CM for future enhancements.

Recent Developments In Monochromatic Microprobe X-Ray Fluorescence (MMXRF)

1998 ◽  
Vol 4 (S2) ◽  
pp. 378-379
Author(s):  
Z. W. Chen ◽  
D. B. Wittry
Keyword(s):  
Materials Science ◽  
High Vacuum ◽  
Three Dimensional ◽  
High Sensitivity ◽  
X Rays ◽  
Fluorescence Excitation ◽  
X Ray ◽  
Quantitative Microanalysis ◽  
Recent Developments ◽  
Fifth Order

A monochromatic x-ray microprobe based on a laboratory source has recently been developed in our laboratory and used for fluorescence excitation. This technique provides high sensitivity (ppm to ppb), nondestructive, quantitative microanalysis with minimum sample preparation and does not require a high vacuum specimen chamber. It is expected that this technique (MMXRF) will have important applications in materials science, geological sciences and biological science.Three-dimensional focusing of x-rays can be obtained by using diffraction from doubly curved crystals. In our MMXRF setup, a small x-ray source was produced by the bombardment of a selected target with a focused electron beam and a toroidal mica diffractor with Johann pointfocusing geometry was used to focus characteristic x-rays from the source. In the previous work ∼ 108 photons/s were obtained in a Cu Kα probe of 75 μm × 43 μm in the specimen plane using the fifth order reflection of the (002) planes of mica.

scholarly journals 3D IMAGING OF INDIVIDUAL PARTICLES: A REVIEW

2012 ◽  
Vol 31 (2) ◽  
pp. 65 ◽  
Author(s):  
Eric Pirard
Keyword(s):  
Literature Review ◽  
Digital Imaging ◽  
Systems Analysis ◽  
3D Imaging ◽  
Materials Science ◽  
Recent Literature ◽  
Three Dimensional ◽  
Shape Estimation ◽  
Individual Particles ◽  
Made In

In recent years, impressive progress has been made in digital imaging and in particular in three dimensional visualisation and analysis of objects. This paper reviews the most recent literature on three dimensional imaging with a special attention to particulate systems analysis. After an introduction recalling some important concepts in spatial sampling and digital imaging, the paper reviews a series of techniques with a clear distinction between the surfometric and volumetric principles. The literature review is as broad as possible covering materials science as well as biology while keeping an eye on emerging technologies in optics and physics. The paper should be of interest to any scientist trying to picture particles in 3D with the best possible resolution for accurate size and shape estimation. Though techniques are adequate for nanoscopic and microscopic particles, no special size limit has been considered while compiling the review.

Effects of Inclination Angle of Ribs on the Flow Behavior in Rectangular Ducts

2004 ◽  
Vol 126 (4) ◽  
pp. 692-699 ◽  
Author(s):  
Xiufang Gao ◽  
Bengt Sunde´n
Keyword(s):  
Velocity Component ◽  
Flow Direction ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Fluid Flows ◽  
Streamwise Velocity ◽  
Flow Structures ◽  
Local Flow ◽  
Flow Motion ◽  
Streamwise Velocity Component

The flow behavior in rib-roughened ducts is influenced by the inclination of ribs and the effect is investigated in the present study by Particle Image Velocimetry (PIV). The local flow structures between two adjacent ribs were measured. The Reynolds number was fixed at 5800. The flow field description was based on the PIV results in planes both parallel and perpendicular to the ribbed walls at various locations. The rib angle to the main flow direction was varied as 30 deg, 45 deg, 60 deg and 90 deg. The ribs induce three dimensional flow fields. The flow separation and reattachment between adjacent ribs are clearly observed. In addition, the inclined ribs are found to alter the spanwise distribution of the streamwise velocity component. The streamwise velocity component has its highest values at the upstream end of the ribs, and decreases continuously to its lowest values at the downstream end. Strong secondary flow motion occurs over the entire duct cross section for the inclined ribs. The flow structures between two consecutive ribs show that the fluid flows along the ribs from one end of the ribs to the other end, and then turns back at the transverse center. Downwash and upwash flows are observed at the upstream end and downstream end of the ribs, respectively.

scholarly journals Barriers to front propagation in laminar, three-dimensional fluid flows

2018 ◽  
Vol 97 (3) ◽  
Author(s):  
Minh Doan ◽  
J. J. Simons ◽  
Katherine Lilienthal ◽  
Tom Solomon ◽  
Kevin A. Mitchell
Keyword(s):  
Three Dimensional ◽  
Fluid Flows ◽  
Front Propagation
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