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Applications of Nanotechnology to Bioprocessing
Published in Yubing Xie, The Nanobiotechnology Handbook, 2012
Susan T. Sharfstein, Sarah Nicoletti
While the majority of 3D culture devices are targeted at tissue engineering, a few have more general applicability. Anada et al. (2010) recently reported a novel multicellular aggregate (spheroid) culture device that utilizes thin polydimethylsiloxane membrane deformation by decompression. In this study, a thin PDMS membrane was placed upon an acrylic plate in which multiple cavities (1535 holes, 1.0 mm in diameter) had been generated using a programmable micromilling system. These cavities were connected with a silicon tube to decompress the spaces between the membrane and the cavities. Thus, the PDMS membrane could be deformed into hemispherical cavities. After treating the PDMS membrane with Pluronic (F-127) to prevent cell adhesion, cells were seeded onto the membrane and the membrane was deformed by vacuum. After 5 days of culture, the pressure was raised from vacuum back to atmospheric pressure, and the spheroids on the PDMS membrane were then retrieved from the culture device using a plastic pipette. Using this technique, they were able to generate spheroids of human osteosarcoma MG63 cells and human hepatoma cell line HepG2. These spheroids could presumably be used for a variety of applications including drug screening and tissue engineering.
Common Heat Treatment Practices
Published in Bankim Chandra Ray, Rajesh Kumar Prusty, Deepak Nayak, Phase Transformations and Heat Treatments of Steels, 2020
Bankim Chandra Ray, Rajesh Kumar Prusty, Deepak Nayak
The main aim of obtaining spheroids structure is to obtain maximum softness, ductility, and machinability with minimum hardness in the material. It is applied to high-alloy tool steels and high-carbon steels to improve machinability and ductility. Low-carbon steels may be spheroidized for cold forming, such as tubing. A microstructure of coarse spheroidized cementite (or alloy carbides) particles embedded in a ferrite matrix is generally seen in this case.
Geodesy
Published in Basudeb Bhatta, Global Navigation Satellite Systems, 2021
A spheroid is defined by either the semi-major axis (a) and the semi-minor axis (b), or by semi-major axis and the flattening (f). The flattening is the difference in length between the two axes. The flattening is f=a–b/a
Enhancing ball grid array (BGA) component design and reliability using a novel reliability-based design optimization (RBDO) methodology
Published in Mechanics of Advanced Materials and Structures, 2023
Sinda Ghenam, Abdelkhalak El Hami, Khalil Dammak, Wajih Gafsi, Ali Akrout, Mohamed Haddar
Researchers have used the flattened sphere shape to model the weld joint without explicitly mentioning it. This shape is actually a spheroid, which is a flattened ellipsoid of revolution. Flattened spheroids are adopted instead of spheres, in response to the design and manufacturing requirements of printed circuit boards. BGA components have solder balls on their bottom side arranged in a regular grid, and spherical solder balls cannot align accurately with the board’s contacts. Flattened spheroids allow for better alignment with the grid and form a solid and reliable solder joint, which has a larger contact surface than spheres, increasing mechanical strength. This is extremely crucial since BGA components are often subjected to shock and vibration forces during use. Figure 6(a) portrays a flattened spheroid.
An Oblate Spheroid Base Isolator and Floating Surface Diaphragm for Seismic Protection of Liquid Storage Tank
Published in Journal of Earthquake Engineering, 2022
Consider the initial position (rest position) of an oblate spheroid isolator as presented in Fig. 1. The initial geometry of the system is shown in Fig. 1(a), and Fig. 1(b) shows the displaced geometry of the system in vertical x-z plane and rotation about the other horizontal axis (y-axis). The isolator has an elliptical shape in any of its vertical plane from its center. The oblate spheroid is an ellipse rotated about its minor axis. The isolator has a major radius, rx along the two horizontal axes (x- and y-axes) and minor radius, rz along the vertical axis (z-axis). In the OSBI system, the major radius is always greater than minor radius (rx > rz). The rotational angle of the OSBI system considered to vary:. The eccentricity, e of the oblate spheroid is a relationship between the two radii given as
Investigation of glass transition behavior in a rice kernel drying process by mathematical modeling
Published in Drying Technology, 2020
Lijuan Zhao, Junhong Yang, Shanshan Wang, Zhonghua Wu
In previous rice drying models, the geometry of the rice kernel was commonly represented by sphere, spheroid, or ellipsoid shapes. The deviation from the true geometry might lead to large errors in predictions of rice drying characteristics. In this work, the image processing method was used to construct a 3-D body fitted grid for rice kernels. The high magnification digital camera (Olympus SZ-17, Olympus Shanghai, China) was used to take the 2-D image of a brown rice kernel on a white background paper. Then, the rice kernel was rotated by an angle of 15° and another image was taken, as shown in Figure 1(a). By repeating it, twelve 2D images were obtained for the rice kernel. These 2D images were then imported into a CAD software and reconstructed into a 3D body fitted physical geometry shown in Figure 1(b). Next, the geometry was imported to the software-COMSOL Multiphysics 4.2 for meshing. Figure 1(c) shows the body fitted mesh for the brown rice kernel with 31350 tetrahedron elements.