An Analytical Method for Expansion Chambers With Continuously Varying Cross-Sectional Area

2004 ◽  
Vol 126 (2) ◽  
pp. 173-183
Author(s):  
M. Utsumi
Keyword(s):  
Analytical Method ◽  
Broadband Noise ◽  
Cross Sectional Area ◽  
Characteristic Functions ◽  
Sectional Area ◽  
Algebraic Equations ◽  
Expansion Chamber ◽  
Cross Sectional ◽  
Linear Algebraic Equations ◽  
The Galerkin Method

An analytical method is applied to predict the acoustic attenuation performance of expansion chambers with continuously varying cross-sectional area. A feature of the present method is the use of spherical coordinates whose origin is at the top of the cone that is tangent to the wall of the expansion chamber. By this means, the characteristic functions can be analytically determined despite the non-uniform geometry of the expansion chamber. Using the Galerkin method, a variational principle is transformed into linear algebraic equations that are solved to determine the transmission coefficient of the expansion chamber. Numerical results are provided for the case where broadband noise attenuation is achieved.

True Cross Sectional Area of Screw Threads With Helix and Root Radius Geometries Taken Into Consideration

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
Toshimichi Fukuoka ◽  
Masataka Nomura
Keyword(s):  
Cross Sectional Area ◽  
Equivalent Diameter ◽  
Sectional Area ◽  
Algebraic Equations ◽  
Root Radius ◽  
Cross Sectional ◽  
Threaded Fasteners ◽  
Fine Pitch ◽  
Screw Threads ◽  
External Loads

When evaluating the strength of threaded fasteners under external loads, stress area is commonly used. However, in order to elucidate the mechanical behavior of bolted joints more rigorously and extensively, it is desired to derive an analytical expression of the true cross sectional area of screw threads, with the effects of the helix and root radius taken into account. In this paper, a series of closed-form algebraic equations, which can calculate true cross sectional areas of internal and external screw threads, is derived. The equations obtained can be applied to both metric and inch screw threads with a coarse or a fine pitch. Then, the equivalent diameter of the true sectional area is defined and compared with the pitch diameter and stress area diameter.

Reynolds Study of the Flow Induced Noise

2011 ◽  
Vol 110-116 ◽  
pp. 4615-4622
Author(s):  
Deepesh Kumar Singh ◽  
G. Bandhyopadhyay
Keyword(s):  
Circular Cross Section ◽  
Aircraft Engine ◽  
Broadband Noise ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Noise Emission ◽  
Cross Sectional ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Flow Induced Noise

2D Large Eddy Simulation turbulence model coupled with Ffowcs-Williams-Hawkins model and Boundary Element Method is used to perform a study of the effect of the Reynolds number on the broadband noise emitted due to the incompressible fluid structure interaction. The method is then used to calculate the broadband noise emitted by the aerodynamic flow over different shape bodies having same cross-sectional area with the intent to know the most suitable cross sectional geometry of the fuel manifolds in the aircraft engine afterburner in terms of minimum noise emission. The results obtained suggests that a 5dB benefit in sound emission could be obtained by the halving the diameter of the circular cross-section used for the fuel manifolds, to make them elliptical keeping cross sectional area constant.

scholarly journals ANALISIS KOLOM BETON BERTULANG PADA PENAMPANG PERSEGI BERLUBANG

2019 ◽  
Vol 11 (1) ◽  
pp. 19-26
Author(s):  
Amrun Nasution ◽  
Mukhlis Islam
Keyword(s):  
Reinforced Concrete ◽  
Axial Force ◽  
Analytical Method ◽  
Concrete Columns ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Power Difference ◽  
Strain Relationship ◽  
Spread Sheet

Installation of the pipe in the column (conduit) such as electrical and sanitary plumbing installations are found in the structure of reinforced concrete columns. This causes it to be a hollow column. The existence of holes cause a reduction in cross sectional area of the column and can result in reduced strength of a column. The purpose of this study was to know the  power  difference  hollow concrete  columns  with  concrete  columns  are not hollow and produce an analysis of the interaction in the form graphics axial force (Pn) and nominal torque (Mn). The analytical method developed by using square column spread sheet applications and use the stress-strain relationship hognestad. Analysis of the hollow square column in this study as many as 720 samples. This study used 300x300-600x600 mm dimensions with an increase of 100 mm. Quality concrete (f'c) used was 25-30 MPa to 2.5 MPa rise. Quality reinforcement (fy) used was 400 MPa and the ratio of the reinforcement taken from 1% -8% with an increase of 2% of the cross sectional area of the column, with the amount of reinforcement as much as 12-20 pieces of reinforcement to rise 4 pieces. Widely used hole that is 3% -7%, with an increase of 1%. The analysis showed a decrease in Pn-Mn hollow column to column was not perforated. The decrease Pn maximum of 7.20% in the area of hole 7% by eccentricity to d amounting to 8.01% and the maximum Mn decrease of 10.91% in the area of hole 7% by eccentricity to d amounting to 20.51%.

Anatomy of the intestine of Ascaris suum: a three dimensional study with silicone rubber casts

1977 ◽  
Vol 55 (7) ◽  
pp. 1110-1117
Author(s):  
Robert P. Harpur
Keyword(s):  
Body Wall ◽  
Female Worm ◽  
Ascaris Suum ◽  
Three Dimensional ◽  
Cross Sectional Area ◽  
The Body ◽  
Sectional Area ◽  
Expansion Chamber ◽  
Cross Sectional ◽  
Posterior Intestine

To facilitate studies of the physiology of Ascaris suum the relations between the intestine and the other organs were investigated. The anterior intestine, which starts, with a thin-walled expansion chamber, is held by connective tissue and by the bellies of muscle cells. A coarctation of the intestine marks the junction of the anterior and midintestine and in the female this narrowing occurs near the genital pore. The midintestine lies free amongst the reproductive organs and terminates near the most posterior excursions of the ovaries and uteri in the female, and of the testis in the male. The posterior intestine is attached continuously, but not initially circumferentially, to the body wall. Relative lengths for the different parts of the female worm are given and microfil casts made in situ with both sexes yielded information about the relative volumes of the midintestine and posterior intestine. The coarctation is the narrowest pan of the intestine and the largest cross-sectional area is reached at the start of the posterior intestine. The attachments to the body wall indicate that the anterior and posterior intestine change length like an accordion when the muscles contract but the cross-sectional area of the lumen is decreased by dorsoventral compression.

Pelvic Canal Narrowing Caused by Triple Pelvic Osteotomy in the Dog

1994 ◽  
Vol 07 (03) ◽  
pp. 110-113 ◽  
Author(s):  
D. L. Holmberg ◽  
M. B. Hurtig ◽  
H. R. Sukhiani
Keyword(s):  
Postoperative Complications ◽  
Pelvic Osteotomy ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Canal Width ◽  
Operative Complications ◽  
Post Operative Complications

SummaryDuring a triple pelvic osteotomy, rotation of the free acetabular segment causes the pubic remnant on the acetabulum to rotate into the pelvic canal. The resulting narrowing may cause complications by impingement on the organs within the pelvic canal. Triple pelvic osteotomies were performed on ten cadaver pelves with pubic remnants equal to 0, 25, and 50% of the hemi-pubic length and angles of acetabular rotation of 20, 30, and 40 degrees. All combinations of pubic remnant lengths and angles of acetabular rotation caused a significant reduction in pelvic canal-width and cross-sectional area, when compared to the inact pelvis. Zero, 25, and 50% pubic remnants result in 15, 35, and 50% reductions in pelvic canal width respectively. Overrotation of the acetabulum should be avoided and the pubic remnant on the acetabular segment should be minimized to reduce postoperative complications due to pelvic canal narrowing.When performing triple pelvic osteotomies, the length of the pubic remnant on the acetabular segment and the angle of acetabular rotation both significantly narrow the pelvic canal. To reduce post-operative complications, due to narrowing of the pelvic canal, overrotation of the acetabulum should be avoided and the length of the pubic remnant should be minimized.

DETERMINATION OF THE FUNCTION OF THE ROD’S CROSS-SECTIONAL AREA USING VIBRATION EIGENFREQUENCIES

2020 ◽  
Vol 0 (4) ◽  
pp. 19-24
Author(s):  
I.M. UTYASHEV ◽  
◽  
A.A. AITBAEVA ◽  
A.A. YULMUKHAMETOV ◽  
◽  
...  
Keyword(s):  
Cross Sectional Area ◽  
Variable Cross ◽  
Sectional Area ◽  
Longitudinal Vibrations ◽  
Cross Sectional ◽  
Method Error ◽  
Various Boundary Conditions ◽  
Elastic Fixation ◽  
Crosssectional Area

The paper presents solutions to the direct and inverse problems on longitudinal vibrations of a rod with a variable cross-sectional area. The law of variation of the cross-sectional area is modeled as an exponential function of a polynomial of degree n . The method for reconstructing this function is based on representing the fundamental system of solutions of the direct problem in the form of a Maclaurin series in the variables x and λ. Examples of solutions for various section functions and various boundary conditions are given. It is shown that to recover n unknown coefficients of a polynomial, n eigenvalues are required, and the solution is dual. An unambiguous solution was obtained only for the case of elastic fixation at one of the rod’s ends. The numerical estimation of the method error was made using input data noise. It is shown that the error in finding the variable crosssectional area is less than 1% with the error in the eigenvalues of longitudinal vibrations not exceeding 0.0001.

Changes in the parameters of nasal breathing and parameters of the upper respiratory tract during orthognathic operations in patients with II and III skeletal class of jaw anomalies

2020 ◽  
pp. 22-27
Author(s):  
S.Sh. Gammadaeva ◽  
M.I. Misirkhanova ◽  
A.Yu. Drobyshev
Keyword(s):  
Respiratory Tract ◽  
Nasal Cavity ◽  
Nasal Septum ◽  
Cross Sectional Area ◽  
Upper Respiratory Tract ◽  
Sectional Area ◽  
Nasal Breathing ◽  
Cross Sectional ◽  
Skeletal Class ◽  
Upper Respiratory

The study analyzed the functional parameters of nasal breathing, linear parameters of the nasal aperture, nasal cavity and nasopharynx, volumetric parameters of the upper airways in patients with II and III skeletal class of jaw anomalies before and after orthognathic surgery. The respiratory function of the nose was assessed using a rhinomanometric complex. According to rhinoresistometry data, nasal resistance and hydraulic diameter were assessed. According to the data of acoustic rhinometry, the minimum cross-sectional area along the internal valve, the minimum cross-sectional area on the head of the inferior turbinate and nasal septum and related parameters were estimated. According to the CBCT data, the state of the nasal septum, the inferior turbinates, the nasal aperture, the state of the nasal cavity, and the linear values of the upper respiratory tract (nasopharynx) were analyzed. The patients were divided into 4 groups according to the classification of the patency of the nasal passages by

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