scholarly journals Flexion Angles of Finger Joints in Two-Finger Tip Pinching Using 3D Bone Models Constructed from X-Ray Computed Tomography (CT) Images

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Satoshi Shimawaki ◽  
Yoshiaki Nakamura ◽  
Masataka Nakabayashi ◽  
Hideharu Sugimoto

The motion analysis of two-finger tip pinching using the thumb and index finger provides crucial data for designing the motion mechanism of electric prosthetic hands. The purpose of this study is to determine the joints that have high mobility during two-finger tip pinching by measuring the flexion angle of each joint. Ten Japanese men with normal hand were selected. CT images were obtained while the hands adopted the following four postures: a basic posture not pinching a cylinder, and three postures pinching wooden cylinders with different diameters (2, 10, and 30 mm). Three-dimensional bone models of the thumb and index finger were created using the CT images and used to measure the flexion angles of the joints. The flexion angles of the proximal interphalangeal and metacarpophalangeal joints of the index finger significantly decreased as the diameter of the cylinder increased. However, even when the diameter of the cylinder changed, the flexion angle of the distal interphalangeal joint of the index finger, and the flexion and rotation angles of all of the thumb joints did not change. When pinching objects of different sizes with a two-finger tip pinch, the posture of the thumb is fixed, and only the posture of the index finger changes. When designing the two-finger tip pinch motion for an electric prosthetic hand, it is sufficient to drive the joints of the index finger only.

2019 ◽  
Author(s):  
Shota Teramoto ◽  
Satoko Takayasu ◽  
Yuka Kitomi ◽  
Yumiko Arai-Sanoh ◽  
Takanari Tanabata ◽  
...  

Abstract Background: Plants adjust their root system architecture (RSA) against changing environments to optimize their growth. Nondestructive phenotyping of roots beneath the soil not only reveal the response of RSA against environmental stimuli but also allow for designing an ideal RSA for crop cultivation. Generally, roots beneath the soil surface are three-dimensionally visualized using X-ray computed tomography (CT). However, root isolation from X-ray CT images involves a longer time; in addition, CT scanning and reconstruction processes require longer periods. For large-scale root phenotyping, a shorter image acquisition time is required. Thus, the objective of this study is to develop a high-throughput pipeline to visualize rice RSA consisting of radicle and crown roots in the soil, from X-ray CT images.Results: We performed the following three processes to develop the pipeline. First, we used calcined clay with uniform soil particle size as the soil substrate. The size of voids between the soil particles was less than the scanning resolution, resulting in a clear root shape in the CT images. Second, we optimized the parameters for rapid X-ray CT scanning. Higher tube voltage and current produced the highest root-to-soil contrast images. Third, we used a 3-D median filter to reduce noise, and an edge detection alogism to isolate the root segments. The detection limits of the root diameters of the pots of diameters 16 cm and 20 cm were 0.2 mm and 0.3 mm, respectively. Because the crown root diameter of rice is generally higher than 0.2 mm, almost all crown roots could be visualized. Our condition allows for simultaneously performing CT scanning and reconstruction by a high-performance computing technology. Consequently, our pipeline visualizes rice RSA in the soil, requiring less than 10 min (33 s, if a rough image is acceptable) for CT scanning and reconstruction, and 2 min for image processing to visualize rice RSA. We scanned the roots of the upland rice (considered in this study) daily, and our pipeline successfully visualized the root development dynamics over three weeks. Conclusions: We developed a rapid three-dimensional visualization method to visualize rice RSA in the soil using X-ray CT and a fully automated-image processing method known as RSAvis3D. Our methodology allows for high-throughput measuring and requires no manual operators in image processing, thereby providing a potentially efficient large-scale root phenotyping.


2021 ◽  
Author(s):  
Katherine A. Wolcott ◽  
Guillaume Chomicki ◽  
Yannick M. Staedler ◽  
Krystyna Wasylikowa ◽  
Mark Nesbitt ◽  
...  

2021 ◽  
Vol 52 (S1) ◽  
pp. 292-294
Author(s):  
Albert Chin ◽  
Te Jui Yen ◽  
You Da Chen ◽  
Cheng Wei Shih ◽  
Vladimir Gritsenko

Author(s):  
Theodore J. Heindel ◽  
Terrence C. Jensen ◽  
Joseph N. Gray

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.


2003 ◽  
Vol 8 (1) ◽  
pp. 2-6 ◽  
Author(s):  
Wolfgang H Stuppy ◽  
Jessica A Maisano ◽  
Matthew W Colbert ◽  
Paula J Rudall ◽  
Timothy B Rowe

2018 ◽  
Vol 139 ◽  
pp. 75-82 ◽  
Author(s):  
A.H. Galmed ◽  
A. du Plessis ◽  
S.G. le Roux ◽  
E. Hartnick ◽  
H. Von Bergmann ◽  
...  

Author(s):  
Mirka Deza ◽  
Francine Battaglia

Fluidized beds are being used in practice to gasify biomass to create producer gas, a flammable gas that can be used for process heating. However, recent literature has identified the need to better understand and characterize biomass fluidization hydrodynamics, and computational fluid dynamics (CFD) is one approach in this effort. Previous work by the authors considered the validity of using two-dimensional versus three-dimensional simulations to model a cold-flow fluidizing biomass bed configured with a single side port air injection. The side port is introduced to inject air and promote mixing within the bed. Comparisons with experiments indicated that three-dimensional simulations were necessary to capture the fluidization behavior for the more complex geometry. This paper considers the effects of increasing fluidization air flow and side port air flow on the homogeneity of the bed material in a 10.2 cm diameter fluidized bed. Two air injection ports diametrically opposed to each other are also considered to determine their effects on fluidization hydrodynamics. Whenever possible, the simulations are compared to experimental data of time-averaged local gas holdup obtained using X-ray computed tomography. This study will show that increasing the fluidization and side port air flows contribute to a more homogeneous bed. Furthermore, the introduction of two side ports results in a more symmetric gas-solid distribution.


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