scholarly journals Assessing the Capabilities of a New Linear Inversion Method for Quantitative Microwave Imaging

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Loreto Di Donato ◽  
Roberta Palmeri ◽  
Gino Sorbello ◽  
Tommaso Isernia ◽  
Lorenzo Crocco
Keyword(s):  
Numerical Analysis ◽  
Cross Section ◽  
Born Approximation ◽  
Circular Cross Section ◽  
Microwave Imaging ◽  
Inversion Method ◽  
Dielectric Cylinder ◽  
Quantitative Criterion ◽  
Linear Inversion ◽  
Imaging Approach

We investigate the imaging capabilities of a new linear microwave imaging approach, which allows to quantitative retrieve the complex permittivity distribution of unknown nonweak targets. To this end, we carry out a parametric numerical analysis for a canonical scatterer (a homogeneous dielectric cylinder with circular cross section) and derive a quantitative criterion to foresee the method’s applicability. The reliability of the criterion is then tested against noncanonical scatterers to show the effectiveness of the method in imaging nonweak targets and in outperforming the linearized inversion method based on the standard Born approximation.

scholarly journals A Simple Quantitative Inversion Approach for Microwave Imaging in Embedded Systems

2015 ◽  
Vol 2015 ◽  
pp. 1-18 ◽  
Author(s):  
M. Ambrosanio ◽  
R. Scapaticci ◽  
L. Crocco
Keyword(s):  
Real Time ◽  
Quantitative Imaging ◽  
Impedance Matching ◽  
Field Approximation ◽  
Microwave Imaging ◽  
Point Of View ◽  
Inversion Method ◽  
Linear Inversion ◽  
Imaging Results ◽  
Different Shapes

In many applications of microwave imaging, there is the need of confining the device in order to shield it from environmental noise as well as to host the targets and the medium used for impedance matching purposes. For instance, in MWI for biomedical diagnostics a coupling medium is typically adopted to improve the penetration of the probing wave into the tissues. From the point of view of quantitative imaging procedures, that is aimed at retrieving the values of the complex permittivity in the domain under test, the presence of a confining structure entails an increase of complexity of the underlying modelling. This entails a further difficulty in achieving real-time imaging results, which are obviously of interest in practice. To address this challenge, we propose the application of a recently proposed inversion method that, making use of a suitable preprocessing of the data and a scenario-oriented field approximation, allows obtaining quantitative imaging results by means of quasi-real-time linear inversion, in a range of cases which is much broader than usual linearized approximations. The assessment of the method is carried out in the scalar 2D configuration and taking into account enclosures of different shapes and, to show the method’s flexibility different shapes, embedding nonweak targets.

Experimental Study and Numerical Analysis of Water Single-Phase Pressure Drop Across an Array of Circular Micro-Pin-Fins

2011 ◽  
Author(s):  
Jonathan R. Mita ◽  
Weilin Qu ◽  
Marcelo H. Kobayashi ◽  
Frank E. Pfefferkorn
Keyword(s):  
Numerical Analysis ◽  
Pressure Drop ◽  
Cross Section ◽  
Single Phase ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Experimental Results ◽  
Inlet Temperature ◽  
Pin Fins ◽  
Micro Pin Fins

This study investigates pressure drop associated with water liquid single-phase flow across an array of staggered micro-pin-fins having circular cross-section. The micro-pin-fins are micro-end milled out of oxygen free copper and have the following dimensions: 180 micron diameter and 683 micron height. The longitudinal pitch and transverse pitch are equal to 400 microns. Seven water inlet temperatures from 22 to 80 °C, and seventeen maximum mass velocities for each inlet temperature, ranging from 159 to 1475 kg/m2s, were tested. The test module was well insulated to maintain adiabatic conditions. The experimental results were compared to those from a micro-pin-fin array having similar size and geometrical arrangement but a square cross-section. The circular micro-pin-fins were seen to yield a significantly lower pressure drop than the square micro-pin-fins. The present experimental results were also compared with the predictions of several friction factor correlations as well as the results from a three-dimensional numerical analysis. Neither was able to accurately predict the experimental data.

Numerical Analysis and Optimization of Flat Ends Parameters in Pressure Vessels with Rectangular Shape

2014 ◽  
Vol 621 ◽  
pp. 107-112 ◽  
Author(s):  
Bogdan Szybiński ◽  
Paweł Romanowicz
Keyword(s):  
Numerical Analysis ◽  
Stress Concentration ◽  
Cross Section ◽  
Cross Sections ◽  
Rectangular Cross Section ◽  
Circular Cross Section ◽  
Pressure Vessels ◽  
Main Interest ◽  
Rectangular Shape ◽  
Minimum Stress

Cylindrical pressure vessels with circular cross section are commonly used in the construction of various pressure apparatus; however in certain cases other cross sections are applied. The vessels with rectangular and elliptical perpendicular cross section are of the main interest and certain formulas for their calculations are stated in the respective codes [1, 2]. In these appliances flat ends of various shapes are usually used as the vessels caps. Similarly, as for the cylindrical boilers, flat end plates with stress relieve grooves are recommended. Like in the flat ends for cylindrical pipes certain variation of the groove parameters is possible but again no clear suggestion is given how to choose the optimal groove parameters providing the minimum stress concentration [3]. In this paper the numerical analysis and optimization of the admitted by code [1] groove parameters is presented for the pipe with the rectangular cross section subjected to the internal pressure.

Damage Detection in Composite Cylindrical Multilayered Shells with Delaminations

2010 ◽  
Vol 123-125 ◽  
pp. 887-890 ◽  
Author(s):  
Aleksander Muc ◽  
Adam Stawiarski
Keyword(s):  
Wave Propagation ◽  
Numerical Analysis ◽  
Dynamic Behavior ◽  
Cross Section ◽  
Circular Cross Section ◽  
Piezoelectric Sensors ◽  
Structural Dynamic ◽  
Cylindrical Panels ◽  
The Difference ◽  
Computational Procedures

In this study, effective computational procedures are introduced and used to characterize the dynamic behavior of cylindrical panels with circular cross-section having the single delamination between laminate layers. Based on the computed results it is possible to determine the effect of delamination on the overall structural dynamic behavior. Those results are used to quantify the difference between the results of the relevant parameters in the cases of perfect and defected structures. Usually, the wave propagation can be observed with the use of piezoelectric sensors. Therefore, in the next step of our analysis we modeled delaminated structures with a finite number of PZT sensors to consider also their influence on the structural dynamic response. The numerical analysis have been conducted with the use of 3D finite elements. A lot of numerical results allow us to understand better the influence of various parameters on the form of wave propagation in cylindrical multilayered shells.

Experimental and Numerical Study of Double Containment Joint Having Circular Cross-Section Support

2011 ◽  
Vol 287-290 ◽  
pp. 2360-2363
Author(s):  
Ali M. Al Samhan
Keyword(s):  
Numerical Analysis ◽  
Cross Section ◽  
Numerical Study ◽  
Circular Cross Section ◽  
Experimental Results ◽  
Set Up

Bonded structure are commonly of three types, purely adhesive bonded, weld-bonded and adhesive/mechanical structures. Present work concern with experimental set-up of double containment joint with circular cross-section support using photoelasticity techniques. The experimental results were found to be within 5% when compared with the numerical analysis.

scholarly journals The Effects of Piezoelectricity Matrix Constants on the Charge of a Thin Membrane

2017 ◽  
Vol 67 (2) ◽  
pp. 61-68
Author(s):  
Tomáš Kováč ◽  
František Horvát ◽  
Branislav Hučko ◽  
Roland Jančo ◽  
Miloš Musil
Keyword(s):  
Gallium Nitride ◽  
Numerical Analysis ◽  
Cross Section ◽  
Electric Charge ◽  
Circular Cross Section ◽  
Thin Membrane ◽  
Aluminium Gallium Nitride ◽  
Matrix Properties ◽  
The Matrix

AbstractThis article is devoted to the comparison of the influence of the piezoelectric matrix properties on the magnitude of the resulting charge when a thin piezoelectric membrane of circular cross section, made from aluminium gallium nitride (Al-GaN), is loaded. The size of change of the electric charge was determined by the numerical analysis and the by the change of the properties of the piezoelectric matrix. The matrix constants were obtained from various sources introduced in world databases.

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

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