Supersonic drag of three-dimensional bodies with a star-shaped cross section and its calculation

1993 ◽  
Vol 28 (1) ◽  
pp. 42-50 ◽  
Author(s):  
N. A. Ostapenko
Keyword(s):  
Cross Section ◽  
Three Dimensional ◽  
Shaped Cross Section

scholarly journals Microvalve with Trapezoid-Shaped Cross-Section for Deep Microchannels

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1403
Author(s):  
Maho Kaminaga ◽  
Tadashi Ishida ◽  
Toru Omata
Keyword(s):  
Cross Section ◽  
Microfluidic Device ◽  
Cultured Cells ◽  
Three Dimensional ◽  
Lithography Process ◽  
Channel Layer ◽  
Large Particles ◽  
Micrometer Scale ◽  
Liquid Channel ◽  
Shaped Cross Section

Simple microfluidic systems for handling large particles such as three-dimensional (3D) cultured cells, microcapsules, and animalcules have contributed to the advancement of biology. However, obtaining a highly integrated microfluidic device for handling large particles is difficult because there are no suitable microvalves for deep microchannels. Therefore, this study proposes a microvalve with a trapezoid-shaped cross-section to close a deep microchannel. The proposed microvalve can close a 350 μm deep microchannel, which is suitable for handling hundreds of micrometer-scale particles. A double-inclined lithography process was used to fabricate the trapezoid-shaped cross-section. The microvalve was fabricated by bonding three polydimethylsiloxane layers: a trapezoid-shaped liquid channel layer, a membrane, and a pneumatic channel layer. The pneumatic balloon, consisting of the membrane and the pneumatic channel, was located beneath a trapezoid-shaped cross-section microchannel. The valve was operated by the application of pneumatic pressure to the pneumatic channel. We experimentally confirmed that the expansion of the pneumatic balloon could close the 350 μm deep microchannel.

scholarly journals Track design and realization of braiding for three-dimensional variably shaped cross-section preforms

2021 ◽  
Vol 16 ◽  
pp. 155892502110025
Author(s):  
Shao Guowei ◽  
Sun Zhihong ◽  
Zhou Qihong ◽  
Wang Zhenxi ◽  
Wang Bing ◽  
...  
Keyword(s):  
Cross Section ◽  
High Performance ◽  
Three Dimensional ◽  
Variable Cross Section ◽  
Topology Design ◽  
Variable Cross ◽  
Braided Composites ◽  
3D Braided Composites ◽  
Variable Section ◽  
Shaped Cross Section

The preforms of three-dimensional (3D) braided composites have a monolithic structure that is braided with high-performance fibers using 3D braiding technology. Compared with traditional laminate composites, braided composites are widely favored because of their superior overall performance and mechanical properties. The capability of fabricating various yarn structures with a flexible 3D rotary braiding method, however, has not been systematically investigated, especially for a variable-section braiding structure. In accordance with the principles of braiding technology and the characteristics of a 3D braiding structure, in this study, we examined a braiding technology for the production of 3D variably shaped cross-section fabric, focusing on three key factors: the topology design of tracks, the arrangement of carriers, and the matrix algorithm of the braiding of variably shaped cross sections. We calculated new kind of structural synthesis approach to a 3D braiding track for a variable section based on the carrier arrangement characteristic method and completed the entire braiding scheme of the variable cross section. In addition, this approach represents an important step toward a simplified understanding of the carrier motion and the operator-independent operation of a 3D rotary braiding machine.

SAF file: It's really three dimensional file

2018 ◽  
Vol 14 (1) ◽  
pp. 1
Author(s):  
Prof. Dr. Jamal Aziz Mehdi
Keyword(s):  
Cross Section ◽  
Root Canal ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Circular Motion ◽  
Root Canal Treatment ◽  
Metal Core ◽  
Rotating Blade

The biological objectives of root canal treatment have not changed over the recentdecades, but the methods to attain these goals have been greatly modified. Theintroduction of NiTi rotary files represents a major leap in the development ofendodontic instruments, with a wide variety of sophisticated instruments presentlyavailable (1, 2).Whatever their modification or improvement, all of these instruments have onething in common: they consist of a metal core with some type of rotating blade thatmachines the canal with a circular motion using flutes to carry the dentin chips anddebris coronally. Consequently, all rotary NiTi files will machine the root canal to acylindrical bore with a circular cross-section if the clinician applies them in a strictboring manner

ANALYSIS OF THE GENERAL EQUATIONS OF THE TRANSVERSE VIBRATION OF A PIECEWISE UNIFORM VISCOELASTIC PLATE

2020 ◽  
Vol 7 (3) ◽  
pp. 52-56
Author(s):  
MMATMATISA JALILOV ◽  
◽  
RUSTAM RAKHIMOV ◽  
Keyword(s):  
Cross Section ◽  
Transverse Vibration ◽  
Three Dimensional ◽  
Viscoelastic Plate ◽  
Constant Thickness ◽  
Regional Problem ◽  
Rigid Contact ◽  
Under Construction ◽  
Derivatives Of ◽  
Theoretical Results

This article discusses the analysis of the general equations of the transverse vibration of a piecewise homogeneous viscoelastic plate obtained in the “Oscillation of inlayer plates of constant thickness” [1]. In the present work on the basis of a mathematical method, the approached theory of fluctuation of the two-layer plates, based on plate consideration as three dimensional body, on exact statement of a three dimensional mathematical regional problem of fluctuation is stood at the external efforts causing cross-section fluctuations. The general equations of fluctuations of piecewise homogeneous viscoelastic plates of the constant thickness, described in work [1], are difficult on structure and contain derivatives of any order on coordinates x, y and time t and consequently are not suitable for the decision of applied problems and carrying out of engineering calculations. For the decision of applied problems instead of the general equations it is expedient to use confidants who include this or that final order on derivatives. The classical equations of cross-section fluctuation of a plate contain derivatives not above 4th order, and for piecewise homogeneous or two-layer plates the elementary approached equation of fluctuation is the equation of the sixth order. On the basis of the analytical decision of a problem the general and approached decisions of a problem are under construction, are deduced the equation of fluctuation of piecewise homogeneous two-layer plates taking into account rigid contact on border between layers, and also taking into account mechanical and rheological properties of a material of a plate. The received theoretical results for the decision of dynamic problems of cross-section fluctuation of piecewise homogeneous two-layer plates of a constant thickness taking into account viscous properties of their material allow to count more precisely the is intense-deformed status of plates at non-stationary external loadings.

Boundary element method in numerical study of three-dimensional Stokes flows in channels of arbitrary shape

2012 ◽  
Vol 9 (1) ◽  
pp. 94-97
Author(s):  
Yu.A. Itkulova
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Cross Section ◽  
Numerical Study ◽  
Three Dimensional ◽  
Cylindrical Tube ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Periodic Flows ◽  
Element Method

In the present work creeping three-dimensional flows of a viscous liquid in a cylindrical tube and a channel of variable cross-section are studied. A qualitative triangulation of the surface of a cylindrical tube, a smoothed and experimental channel of a variable cross section is constructed. The problem is solved numerically using boundary element method in several modifications for a periodic and non-periodic flows. The obtained numerical results are compared with the analytical solution for the Poiseuille flow.

scholarly journals Influence of technical parameters on the structure of annular axis braided preforms

2021 ◽  
Vol 28 (1) ◽  
pp. 160-168
Author(s):  
Xi Wang ◽  
Guoli Zhang ◽  
Xiaoping Shi ◽  
Ce Zhang
Keyword(s):  
Cross Section ◽  
Rotation Speed ◽  
Technical Parameters ◽  
Braiding Angle ◽  
Shaped Cross Section

Abstract A modified vertical braiding machine and closed annular axis mandrels with a special-shaped cross section were used to braid annular axis preforms under four different technical parameters. After measuring the braiding angles and yarn spacing of the braided preform in different areas of the mandrels, it was found that the braiding angle increased by 20.9% and the yarn spacing decreased by 19.8% when the speed of the yarn carrier was doubled. The braiding angle decreased by 31.1% and the yarn spacing increased by 28.6% when the rotation speed of the mandrels was doubled. The results show that the rotation speed of the mandrel has a slightly greater influence on the braiding angle and the yarn spacing. By using the modified braiding machine to braid the annular axis preforms, multi-layer continuous braided preforms can be achieved on compact equipment. And the structure of the annular axis braided preforms can be changed by changing the technical parameters.

Sign in / Sign up

Export Citation Format

Share Document