Incompressible Laminar Entrance Flow in a Circular Sector Duct

1976 ◽  
Vol 43 (2) ◽  
pp. 357-359 ◽  
Author(s):  
R. L. Wendt ◽  
C. L. Wiginton
Keyword(s):  
Circular Sector ◽  
Entrance Flow

scholarly journals Miniaturized Wideband Loop Antenna Using a Multiple Half-Circular-Ring-Based Loop Structure and Horizontal Slits for Terrestrial DTV and UHD TV Applications

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 2916
Author(s):  
Junho Yeo ◽  
Jong-Ig Lee
Keyword(s):  
Coplanar Waveguide ◽  
Impedance Matching ◽  
Circular Ring ◽  
Loop Antenna ◽  
Digital Television ◽  
Loop Structure ◽  
High Definition ◽  
Circular Sector ◽  
Feed Line ◽  
Length Reduction

A miniaturized wideband loop antenna for terrestrial digital television (DTV) and ultra-high definition (UHD) TV applications is proposed. The original wideband loop antenna consists of a square loop, two circular sectors to connect the loop with central feed points, and a 75 ohm coplanar waveguide (CPW) feed line inserted in the lower circular sector. The straight side of the square loop is replaced with a multiple half-circular-ring-based loop structure. Horizontal slits are appended to the two circular sectors in order to further reduce the antenna size. A tapered CPW feed line is also employed in order to improve impedance matching. The experiment results show that the proposed miniaturized loop antenna operates in the 460.7–806.2 MHz frequency band for a voltage standing wave ratio less than two, which fully covers the DTV and UHD TV bands (470–771 MHz). The proposed miniaturized wideband loop antenna has a length reduction of 21.43%, compared to the original loop antenna.

Design Approach towards Compact Circular Sector Microstrip Antenna with Low Cross Polarization

2021 ◽  
pp. 1-1
Author(s):  
Sudip Kumar Ghosh ◽  
Abhijyoti Ghosh ◽  
Subhradeep Chakraborty ◽  
Lolit Kumar Singh ◽  
Sudipta Chattopadhyay
Keyword(s):  
Microstrip Antenna ◽  
Design Approach ◽  
Cross Polarization ◽  
Circular Sector

scholarly journals Continuous Flow Controlled Synthesis of Gold Nanoparticles Using Pulsed Mixing Microfluidic System

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Guojun Liu ◽  
Xuhao Yang ◽  
Yan Li ◽  
Zhigang Yang ◽  
Wen Hong ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Flow Rate ◽  
Research Work ◽  
Microfluidic System ◽  
Noble Metal Nanoparticles ◽  
Controlled Synthesis ◽  
Entrance Angle ◽  
Section Size ◽  
Pulsed Mixing ◽  
Entrance Flow

To prepare the gold nanoparticles (AuNPs) with uniform sizes, fine morphology, and good monodispersity, a pulsed mixing microfluidic system based on PZT actuation was presented. The system includes PZT micropump and Y type micromixer. By adjusting voltage (entrance flow rate), pulsed frequency, phase, and other parameters, a variety of mixing modes can be achieved, so as to realize the controllable synthesis of nanoparticles in a certain range. By numerical simulation and analysis, the channel section size, entrance angle, and pulse frequency were optimized. Based on the optimized structure and working parameters, the test prototype has been manufactured in lab, and the related synthesis tests of AuNPs were carried out. The test results indicate that AuNPs with uniform morphology and good monodispersity can be synthesized using the system with the section size (0.4 mm × 0.4 mm), the entrance channel angle (60°) under condition of the pulsed frequency (300 Hz), and the entrance flow rate (4 mL/min). The average diameter and its standard deviation of AuNPs synthesized were 21.6 nm, 4.83 nm, respectively. The research work above can be applied to the fields such as the controlled synthesis of noble metal nanoparticles, biomedicine, and microchemical system.

The Sector Problem

1957 ◽  
Vol 24 (4) ◽  
pp. 574-581
Author(s):  
G. Horvay ◽  
K. L. Hanson
Keyword(s):  
Variational Method ◽  
Orthogonal Polynomials ◽  
Biharmonic Equation ◽  
Approximate Solutions ◽  
Circular Sector ◽  
Orthonormal Polynomials ◽  
Circular Boundary ◽  
Stress Functions ◽  
Complete Set ◽  
Derivatives Of

Abstract On the basis of the variational method, approximate solutions f k ( r ) h k ( θ ) , f k ( r ) g k ( θ ) , F k ( θ ) H k ( r ) , F k ( θ ) G k ( r ) of the biharmonic equation are established for the circular sector with the following properties: The stress functions fkhk create shear tractions on the radial boundaries; the stress functions fkgk create normal tractions on the radial boundaries; the stress functions FkHk create both shear and normal tractions on the circular boundary, and the stress functions FkGk create normal tractions on the circular boundary. The enumerated tractions are the only tractions which these function sets create on the various boundaries of the sector. The factors fk(r) constitute a complete set of orthonormal polynomials in r into which (more exactly, into the derivatives of which) self-equilibrating normal or shear tractions applied to the radial boundaries of the sector may be expanded; the factors Fk(θ) constitute a complete set of orthonormal polynomials in θ into which shear tractions applied to the circular boundary of the sector may be expanded; and the functions Fk″ + Fk constitute a complete set of non-orthogonal polynomials into which normal tractions applied to the circular boundary of the sector may be expanded. Function tables, to facilitate the use of the stress functions, are also presented.

Entrance flow in elliptical ducts

1993 ◽  
Vol 17 (12) ◽  
pp. 1079-1096 ◽  
Author(s):  
K. Velusamy ◽  
Vijay K. Garg
Keyword(s):  
Entrance Flow
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