Full scattering profile of tissues with elliptical cross sections

2018 ◽  
Author(s):  
Hamootal Duadi ◽  
Idit Feder ◽  
Dror Fixler
Keyword(s):  
Cross Sections ◽  
Elliptical Cross

Numerical Analysis of Branch Mechanical Response to Loading

2019 ◽  
Vol 45 (4) ◽  
Author(s):  
Barbora Vojáčková ◽  
Jan Tippner ◽  
Petr Horáček ◽  
Luděk Praus ◽  
Václav Sebera ◽  
...  
Keyword(s):  
Finite Element ◽  
Cross Sections ◽  
Mechanical Response ◽  
Mechanical Analysis ◽  
Beam Deflection ◽  
Design System ◽  
Elliptical Cross ◽  
Static Mechanical ◽  
The Difference ◽  
Tree Uprooting

Failure of a tree can be caused by a stem breakage, tree uprooting, or branch failure. While the pulling test is used for assessing the first two cases, there is no device-supported method to assess branch failure. A combination of the optical technique, pulling test, and deflection curve analysis could provide a device-supported tool for this kind of assessment. The aim of the work was to perform a structural analysis of branch response to static mechanical loading. The analyses were carried out by finite element simulations in ANSYS using beam tapered elements of elliptical cross-sections. The numerical analyses were verified by the pulling test combined with a sophisticated optical assessment of deflection evaluation. The Probabilistic Design System was used to find the parameters that influence branch mechanical response to loading considering the use of cantilever beam deflection for stability analysis. The difference in the branch’s deflection between the simulation and the experiment is 0.5% to 26%. The high variability may be explained by the variable modulus of the elasticity of branches. The finite element (FE) sensitivity analysis showed a higher significance of geometry parameters (diameter, length, tapering, elliptical cross-section) than material properties (elastic moduli). The anchorage rotation was found to be significant, implying that this parameter may affect the outcome in mechanical analysis of branch behavior. The branch anchorage can influence the deflection of the whole branch, which should be considered in stability assessment.

Stresses and Deformations of Toroidal Shells of Elliptical Cross Section: With Applications to the Problems of Bending of Curved Tubes and of the Bourdon Gage

1952 ◽  
Vol 19 (1) ◽  
pp. 37-48
Author(s):  
R. A. Clark ◽  
T. I. Gilroy ◽  
E. Reissner
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Practical Interest ◽  
Closed Shell ◽  
Open Shell ◽  
Elliptical Cross Section ◽  
Axially Symmetric ◽  
Elliptical Cross ◽  
Two Parameters ◽  
Toroidal Shells

Abstract This paper is concerned with the application of the theory of thin shells to several problems for toroidal shells with elliptical cross section. These problems are as follows: (a) Closed shell subjected to uniform normal wall pressure. (b) Open shell subjected to end bending moments. (c) Combination of the results for the first and second problems in such a way as to obtain results for the stresses and deformations in Bourdon tubes. In all three problems the distribution of stresses is axially symmetric but only in the first problem are the displacements axially symmetric. The magnitude of stresses and deformations for given loads depends in all three problems on the magnitude of the two parameters bc/ah and b/c where b and c are the semiaxes of the elliptical section, a is the distance of the center of the section from the axis of revolution, and h is the thickness of the wall of the shell. For sufficiently small values of bc/ah trigonometric series solutions are obtained. For sufficiently large values of bc/ah asymptotic solutions are obtained. Numerical results are given for various quantities of practical interest as a function of bc/ah for the values 2, 1, 1/2, 1/4 of the semiaxes ratio b/c. It is suggested that the analysis be extended to still smaller values of b/c and to cross sections other than elliptical.

Glaciological Problems Set by the Control of Dangerous Lakes in Cordillera Blanca, Peru. II. Movement of a Covered Glacier Embedded within a Rock Glacier

1977 ◽  
Vol 18 (79) ◽  
pp. 255-274 ◽  
Author(s):  
Louis Lliboutry
Keyword(s):  
Cross Sections ◽  
Rock Glacier ◽  
Measured Velocity ◽  
Elliptical Cross ◽  
Cordillera Blanca ◽  
The Holocene ◽  
Glacier Tongue ◽  
Proglacial Lake

AbstractIn front of Laguna Parón there is a huge moraine which turns through 90° in the middle of the valley and with a narrow covered glacier on the top. It has been studied by electrical exploration, and using the displacements of 43 marked boulders on the glacier. Assuming a uniform balance on the glacier tongue and semi-elliptical cross-sections, it has been possible to estimate this balance and the glacier thickness. A great amount of the measured velocity comes from the creep of the moraine itself, which seems 10 be a kind of rock glacier, probably without interstitial ire. It must have taken all the Holocene to be formed. During its complex history a proglacial lake must have formed at some time, the rupture of which explains the crooked form.

Study on non-local effects in dimers of circular and elliptical cross-sections

2021 ◽  
Author(s):  
Xi Zhang ◽  
Wenyuan Wu ◽  
Yanchun Gong ◽  
Suhong He ◽  
Fangping Wu ◽  
...  
Keyword(s):  
Absorption Spectrum ◽  
Electric Field ◽  
Cross Section ◽  
Cross Sections ◽  
Field Enhancement ◽  
Radius Of Curvature ◽  
Electric Field Enhancement ◽  
Nonlocal Effects ◽  
Elliptical Cross ◽  
Non Local

Abstract The nonlocal effects of dimers consisted of two cylinders are studied, whose cross section is elliptical. Importantly, the results with dimers whose cross section is circular are compared. For comparison, the curvature of the ellipse is set the same with the circle, and four different geometries are considered. The electric field enhancement at the gap center and the absorption spectrum of the dimers are calculated. For the second geometry, either the electric field enhancement at the gap center or the absorption spectrum is approximately calculated using the first geometry, the frequencies corresponding to the peaks are totally different. Similarly, for the fourth geometry, either the electric field enhancement at the gap center or the absorption spectrum is approximately calculated using the third geometry, the disciplines of the peak values change as radius of curvature increases are totally different.

scholarly journals Correction to: Non-localised contact between beams with circular and elliptical cross-sections

2020 ◽  
Vol 66 (4) ◽  
pp. 1051-1051
Author(s):  
Marco Magliulo ◽  
Jakub Lengiewicz ◽  
Andreas Zilian ◽  
Lars A. A. Beex
Keyword(s):  
Open Access ◽  
Cross Sections ◽  
Elliptical Cross ◽  
Open Access Publication

The article “Non-localised contact between beams with circular and elliptical cross-sections”, written by “Marco Magliulo, Jakub Lengiewicz, Andreas Zilian and Lars A. A. Beex”, was originally published Online First without open access. After publication in volume 65, issue 5, page 1247–1266 the authors decided to opt for Open Choice and to make the article an open access publication. Therefore, the copyright of the article has been changed to ©   The Author(s) 2020

Numerical Study of Incomplete Stent Apposition Caused by Deploying Undersized Stent in Arteries With Elliptical Cross Sections

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Bo Jiang ◽  
Vikas Thondapu ◽  
Eric K. W. Poon ◽  
Peter Barlis ◽  
Andrew S. H. Ooi
Keyword(s):  
Shear Rate ◽  
Cross Section ◽  
Cross Sections ◽  
Numerical Study ◽  
Circular Cross Section ◽  
Blood Stream ◽  
Cfd Simulations ◽  
Elliptical Cross ◽  
Incomplete Stent Apposition ◽  
Computational Fluid Dynamics Cfd

Incomplete stent apposition (ISA) is one of the causes leading to poststent complications, which can be found when an undersized or an underexpanded stent is deployed at lesions. The previous research efforts have focused on ISA in idealized coronary arterial geometry with circular cross section. However, arterial cross section eccentricity plays an important role in both location and severity of ISA. Computational fluid dynamics (CFD) simulations are carried out to systematically study the effects of ISA in arteries with elliptical cross section, as such stents are partially embedded on the minor axis sides of the ellipse and malapposed elsewhere. Overall, ISA leads to high time-averaged wall shear stress (TAWSS) at the proximal end of the stent and low TAWSS at the ISA transition region and the distal end. Shear rate depends on both malapposition distance and blood stream locations, which is found to be significantly higher at the inner stent surface than the outer surface. The proximal high shear rate signifies increasing possibility in platelet activation, when coupled with low TAWSS at the transition and distal regions which may indicate a nidus for in-stent thrombosis.

scholarly journals Computational Study of Zigzag Spacer Design with Elliptical Cross-Section Filaments

2020 ◽  
Vol 307 ◽  
pp. 01047
Author(s):  
Gohar Shoukat ◽  
Farhan Ellahi ◽  
Muhammad Sajid ◽  
Emad Uddin
Keyword(s):  
Mass Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Computational Study ◽  
Flow Direction ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Two Dimensional ◽  
Permeate Flux ◽  
Elliptical Cross

The large energy consumption of membrane desalination process has encouraged researchers to explore different spacer designs using Computational Fluid Dynamics (CFD) for maximizing permeate per unit of energy consumed. In previous studies of zigzag spacer designs, the filaments are modeled as circular cross sections in a two-dimensional geometry under the assumption that the flow is oriented normal to the filaments. In this work, we consider the 45° orientation of the flow towards the three-dimensional zigzag spacer unit, which projects the circular cross section of the filament as elliptical in a simplified two-dimensional domain. OpenFOAM was used to simulate the mass transfer enhancement in a reverse-osmosis desalination unit employing spiral wound membranes lined with zigzag spacer filaments. Properties that impact the concentration polarization and hence permeate flux were analyzed in the domain with elliptical filaments as well as a domain with circular filaments to draw suitable comparisons. The range of variation in characteristic parameters across the domain between the two different configurations is determined. It was concluded that ignoring the elliptical projection of circular filaments to the flow direction, can introduce significant margin of error in the estimation of mass transfer coefficient.

The location of p-dichlorobenzene in a single crystal of zeolite H-ZSM-5 at high sorbate loading

1996 ◽  
Vol 52 (1) ◽  
pp. 140-144 ◽  
Author(s):  
H. van Koningsveld ◽  
J. C. Jansen ◽  
H. van Bekkum
Keyword(s):  
Single Crystal ◽  
Cross Sections ◽  
Unit Cell ◽  
Molecular Axis ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Acta Cryst ◽  
Elliptical Cross ◽  
X Ray ◽  
Structural Aspects

The crystal structure of a high-loaded complex of H-ZSM-5 with eight molecules of p-dichlorobenzene per unit cell has been solved by single-crystal X-ray diffraction. The orthorhombic space group P212121 with a = 20.102 (6), b = 19.797 (9), c = 13.436 (3) Å and V = 5347 (3) Å3 has four Si23.92Al0.08O48.2C6H4Cl2 units per unit cell. Dx = 2.164 Mg m−3, λ(MoKα) = 0.71073 Å and μ(Mo Kα) = 0.876 mm−1. The final R(wR) = 0.046 (0.039), w = 1/σ 2(F), for 6090 observed reflections with I > 1.0σ(I) measured at 293 K. The straight channel parallel to [010] is slightly corrugated. The elliptical cross sections have limiting apertures of 6.0 × 4.9 Å (r oxygen = 1.35 Å). The sinusoidal channel parallel to [100] is elliptical with major and minor axes of 6.1 × 4.8 Å, respectively. One of the two independent p-dichlorobenzene molecule lies at the intersection of the straight and sinusoidal channels with its long molecular axis almost parallel to (100) and deviating ~8° from [010]. The second p-dichlorobenzene molecule is in the sinusoidal channel. Its long molecular axis deviates almost 7° from [100] and is practically parallel to (010). The structural aspects are in all details comparable to those in the high-loaded H-ZSM-5/p-xylene complex [van Koningsveld, Tuinstra, van Bekkum & Jansen (1989). Acta Cryst. B45, 423–431] , except for the main interaction forces between the p-dichlorobenzene molecules at the channel intersection.

Elastic waves in arrays of elliptic inclusions

2005 ◽  
Vol 220 (9-10) ◽  
Author(s):  
Sebastien Guenneau ◽  
Alexander B. Movchan
Keyword(s):  
Cross Sections ◽  
Elastic Waves ◽  
Fused Silica ◽  
Periodic Array ◽  
Filling Fraction ◽  
Elliptical Cross ◽  
Macro Cell ◽  
Doubly Periodic Array ◽  
Elliptical Cylinders

AbstractWe consider in-plane elastic waves propagating through a doubly periodic array of cylinders of Tantalum (with both circular and elliptical cross-sections) which are embedded in a matrix of fused silica. We find some sonic gap for fairly small filling fractions of the cylinders which eventually vanish in the limit of high-filling fraction. In the case of a doubly periodic array of elliptical cylinders, removal of a cylinder within a macro-cell leads to two localised eigenstates.

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