scholarly journals Design and demonstration of an acoustic right-angle bend

2017 ◽  
Vol 142 (1) ◽  
pp. 84-89 ◽  
Author(s):  
Wenjia Lu ◽  
Han Jia ◽  
Yafeng Bi ◽  
Yuzhen Yang ◽  
Jun Yang
Keyword(s):  
Angle Bend

On the effect of a sharp bend in a fully developed turbulent pipe-flow

1968 ◽  
Vol 34 (3) ◽  
pp. 595-608 ◽  
Author(s):  
M. J. Tunstall ◽  
J. K. Harvey
Keyword(s):  
Secondary Flow ◽  
Pipe Flow ◽  
Secondary Circulation ◽  
Turbulent Pipe Flow ◽  
Sharp Bend ◽  
Random Frequency ◽  
Angle Bend ◽  
Circulatory Flow ◽  
Flow Through ◽  
Upstream Flow

It has been found experimentally that the turbulent pipe flow through a mitred, right-angle bend produces a downstream secondary circulation which does not conform to the twin-circulatory flow usually to be found in pipe bends. The secondary flow is dominated by a single circulation about the axis in either a clockwise or an anticlockwise sense, between which it switches abruptly at a low, random frequency. The phenomenon is explained in terms of the asymmetry of the inner wall separation and the turbulent axial circulation generated in the upstream flow.

INVESTIGATIONS OF LIQUID METAL FLOW THROUGH A RIGHT ANGLE BEND UNDER FUSION RELEVANT CONDITIONS

1993 ◽  
pp. 1276-1280 ◽  
Author(s):  
L. Barleon ◽  
L. Bühler ◽  
K.J. Mack ◽  
S. Molokov ◽  
R. Stieglitz ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Metal Flow ◽  
Liquid Metal Flow ◽  
Angle Bend ◽  
Flow Through

On the Use of the Finite Element Method on Some Acoustical Problems

1982 ◽  
Vol 104 (1) ◽  
pp. 108-112 ◽  
Author(s):  
L. Cederfeldt
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Analytical Methods ◽  
The Finite Element Method ◽  
Expansion Chamber ◽  
Low Frequencies ◽  
Angle Bend ◽  
Complicated Geometry ◽  
Sound Reduction ◽  
Element Method

In a project carried out in 1974-1975, financially supported by the National Swedish Council for Building Research, the finite element method was applied on some acoustical problems to illustrate the possibilities of the method. Calculations have been made for the following examples; sound attenuation of a lined right angle bend, a lined straight duct, and expansion chamber and the sound reduction of a resilient skin. The FEM has its power for small geometries particularly at low frequencies, that is, when analytical methods usually are weak. The more complicated geometry and boundary conditions of the studied problem may be the more powerful the FEM is compared to analytical methods.

209 VIABILITY OF PORCINE EMBRYOS VITRIFIED BY THE METAL MESH VITRIFICATION METHOD AFTER SURGICAL OR NONSURGICAL TRANSFER

2007 ◽  
Vol 19 (1) ◽  
pp. 221 ◽  
Author(s):  
Y. Fujino ◽  
Y. Nakamura ◽  
H. Kobayashi ◽  
S. Nakano ◽  
C. Suzuki ◽  
...  
Keyword(s):  
Liquid Nitrogen ◽  
Uterine Horn ◽  
Outer Diameter ◽  
Metal Mesh ◽  
Angle Bend ◽  
Fetal Bovine ◽  
Inner Diameter ◽  
Polyethylene Tubing ◽  
Practical Measure ◽  
Uterine Body

The aim of the present study was to evaluate viability of porcine embryos vitrified by the metal mesh vitrification (MMV) method after surgical or nonsurgical transfer. Prepubertal gilts were treated with eCG and hCG (= Day 0), and then inseminated artificially. Expanding blastocysts that were about 200 �m in diameter were collected on Day 7. The embryos were equilibrated in 7.5% ethylene glycol (EG) + 7.5% DMSO + 20% fetal bovine serum (FBS) in PBS at 37�C for 5 min, and then transferred into 15% EG + 15% DMSO + 0.6 M trehalose + 20% FBS in PBS for 1 min. Embryos in groups of 5 were transferred in a minimum volume of the vitrification solution (less than 1 �L) onto stainless steel mesh (75 �m screen size, 1.5 mm in width by 10 mm in length, with a 3-mm right-angle bend), and then plunged into liquid nitrogen. The mesh was stored in a 1.8-mL cryotube submerged in liquid nitrogen. Warming and dilution were performed by moving the mesh from liquid nitrogen into 0.5 M trehalose + 20% FBS in PBS at 37�C for 5 min. Embryos were rinsed twice in NCSU37 + 10% FBS (mNCSU37) for 5 min. After being vitrified, embryos in groups of 20 per recipient were suspended in modified NCSU37 medium and then transferred into gilts either by surgical transfer (5 gilts) or by nonsurgical transfer (6 sows). For surgical transfer, embryos suspended in 0.1 mL of medium were transferred into the uterine horn at 15 cm above the uterine body, which was about 35 cm from the external uterine orifice. For nonsurgical transfer, an intrauterine catheter made from polyethylene tubing (1.2 m long, 3.0 mm outer diameter, 0.5 mm inner diameter) was used. A spiral guide inserted through the vagina into the cervix was used to guide the catheter into one uterine horn. The catheter was moved through the cervix and along the uterine horn. Then, embryos suspended in 1 mL of medium were transferred. Pregnancy was assessed by ultrasonography at 30 days post-estrus. With surgical transfer, 4 of 5 recipients became pregnant, and 3 gilts farrowed a total of 21 (10, 8, 3) live piglets; the fourth gilt aborted one fetus on Day 34. With nonsurgical transfer, 3 of 6 sows became pregnant. The present study demonstrates that vitrified porcine embryos can develop after both surgical and nonsurgical transfer to recipients. As a practical measure, nonsurgical transfer of vitrified porcine blastocysts may be used instead of surgical transfer.

Sound Radiation from Vehicles on the Right-Angle Bend of the Road

2019 ◽  
Vol 240 (2) ◽  
pp. 141-161
Author(s):  
O. P. Piddubniak ◽  
N. G. Piddubniak
Keyword(s):  
Sound Radiation ◽  
The Road ◽  
Angle Bend ◽  
The Right

The diffraction of surface waves by a terminated structure in the form of a right-angle bend

1962 ◽  
Vol 10 (6) ◽  
pp. 679-686 ◽  
Author(s):  
T. Chu ◽  
R. Kouyoumjian ◽  
F. Karal ◽  
S. Karp
Keyword(s):  
Surface Waves ◽  
Angle Bend

Three-Dimensional Tube Geometry Control for Rotary Draw Tube Bending, Part 2: Statistical Tube Tolerance Analysis and Adaptive Bend Correction

2000 ◽  
Vol 123 (2) ◽  
pp. 266-271 ◽  
Author(s):  
Huazhou Lou ◽  
Kim A. Stelson
Keyword(s):  
Three Dimensional ◽  
Tolerance Analysis ◽  
Bend Angle ◽  
Tube Bending ◽  
Process Error ◽  
Process Tolerance ◽  
Bending Process ◽  
Angle Bend ◽  
Geometry Error ◽  
Tube Geometry

The control of each individual bend and overall process is presented in Part 1 of the paper. In Part 2 of the paper, statistical methods are used to analyze and improve 3-D tube bending accuracy. The relationship between bending process error and tube geometry error is obtained with Monte Carlo simulation. For the same tube tolerance requirement, the required process tolerance varies in a large range based on tube geometry. Among the three bending errors: bend angle, bend plane and distance between bends, bend angle error has the largest influence on tube error. For a tube with multiple bends, the overall tube geometry error can be minimized by intentionally modifying the nominal values of the bends to be made based on the errors in the existing bends. The required modification of the bending commands is calculated with an adaptive bend correction algorithm.

Prevention of Kinking of a Percutaneous Transtracheal Intravenous Catheter 

1995 ◽  
Vol 82 (1) ◽  
pp. 288-291 ◽  
Author(s):  
Lorraine Sdrales ◽  
Jonathan L. Benumof
Keyword(s):  
Small Angle ◽  
P Value ◽  
Jet Ventilation ◽  
Intravenous Catheter ◽  
Quick Method ◽  
Pressure Oxygen ◽  
Chi Squared ◽  
High Pressure Oxygen ◽  
Effective Ventilation ◽  
Angle Bend

Background Transtracheal jet ventilation (TTJV) through a percutaneously inserted intravenous/TTJV catheter, using a high-pressure oxygen source and noncompliant tubing is a simple and quick method of effective ventilation, especially in a patient in whom the lungs cannot be ventilated via mask and/or whose trachea cannot be intubated. TTJV becomes impossible if any part of the plastic portion of the TTJV catheter kinks; although the incidence of this problem is not known, kinking of the catheter is most likely to occur as the catheter turns from a predominantly posterior to a predominantly caudad direction. These experiments tested the hypothesis that a small-angle bend in the tip of the TTJV catheter would reduce the requirement to aim the entire TTJV catheter in a caudad-directed orientation. Methods A model of the trachea was designed using polyvinylchloride tubing to observe TTJV catheter insertion and plastic catheter kinking. The TTJV catheters were inserted at 0, 5 degrees, 10 degrees, 15 degrees, 20 degrees, 25 degrees, and 30 degrees angles in trials of 15 times each. Small-angle bends, placed at 2.5 cm from the distal end of the TTJV catheter, of 0, 5 degrees, 10 degrees, 15 degrees, and 20 degrees were used, and each bent TTJV catheter was inserted at each of the above insertion angles 15 times. Results Increasing the angle of insertion decreased the incidence of kinking of the TTJV catheter at every small-angle bend in the tip of the TTJV catheter. Increasing the small-angle bend in the tip of the TTJV catheter decreased the incidence of kinking with every angle of insertion. A small-angle bend in the tip of the TTJV catheter and the angle of insertion often were complementary in their ability to decrease the incidence of kinking. With a cumulative angle of 10 degrees, 98% of the plastic catheters kinked, compared to 0 in trials involving a cumulative angle of 30 degrees or more. Analysis via the chi-squared test yielded a P value of < 0.0001 when comparing incidence of kinking for cumulative angles of 10-30 degrees. Conclusions A modest bend in the tip of the TTJV catheter greatly reduces the sharpness of the angle of insertion required to eliminate kinking of the plastic catheter. Because the risk/benefit ratio is so low, we suggest that a small-angle bend of 15 degrees should always be created and, combined with a 15 degrees angle of insertion, should result in a rare incidence of kinking.

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