scholarly journals Verification of the electromagnetic deep-penetration effect in the real world

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Paolo Baccarelli ◽  
Alessandro Calcaterra ◽  
Fabrizio Frezza ◽  
Fabio Mangini ◽  
Nicholas Ricciardella ◽  
...  
Keyword(s):  
Electromagnetic Waves ◽  
Deep Penetration ◽  
Practical Relevance ◽  
Leaky Waves ◽  
New Approach ◽  
Penetration Effect ◽  
Inhomogeneous Waves ◽  
Lossy Media ◽  
Theoretical Evidence ◽  
First Time

AbstractThe deep penetration of electromagnetic waves into lossy media can be obtained by properly generating inhomogeneous waves. In this work, for the very first time, we demonstrate the physical implementation and the practical relevance of this phenomenon. A thorough numerical investigation of the deep-penetration effects has been performed by designing and comparing three distinct practical radiators, emitting either homogeneous or inhomogeneous waves. As concerns the latter kind, a typical Menzel microstrip antenna is first used to radiate improper leaky waves. Then, a completely new approach based on an optimized 3-D horn TEM antenna applied to a lossy prism is described, which may find applications even at optical frequencies. The effectiveness of the proposed radiators is measured using different algorithms to consider distinct aspects of the propagation in lossy media. We finally demonstrate that the deep penetration is possible, by extending the ideal and theoretical evidence to practical relevance, and discuss both achievements and limits obtained through numerical simulations on the designed antennas.

scholarly journals An Analytical Study of Electromagnetic Deep Penetration Conditions and Implications in Lossy Media through Inhomogeneous Waves

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1595 ◽  
Author(s):  
Paolo Baccarelli ◽  
Fabrizio Frezza ◽  
Patrizio Simeoni ◽  
Nicola Tedeschi
Keyword(s):  
Electromagnetic Waves ◽  
Plane Waves ◽  
Deep Penetration ◽  
Practical Implementation ◽  
Penetration Effect ◽  
Inhomogeneous Waves ◽  
Inhomogeneous Plane ◽  
Lossy Medium ◽  
Lossy Media ◽  
Inhomogeneous Plane Waves

This paper illustrates how the penetration of electromagnetic waves in lossy media strongly depends on the waveform and not only on the media involved. In particular, the so-called inhomogeneous plane waves are compared against homogeneous plane waves illustrating how the first ones can generate deep penetration effects. Moreover, the paper provides examples showing how such waves may be practically generated. The approach taken here is analytical and it concentrates on the deep penetration conditions obtained by means of incident inhomogeneous plane waves incoming from a lossless medium and impinging on a lossy medium. Both conditions and constraints that the waveforms need to possess to achieve deep penetration are analysed. Some results are finally validated through numerical computations. The theory presented here is of interest in view of a practical implementation of the deep penetration effect.

scholarly journals Analytical Investigation on a New Approach for Achieving Deep Penetration in a Lossy Medium: The Lossy Prism

2017 ◽  
pp. 17-24 ◽  
Author(s):  
Fabrizio Frezza ◽  
Patrizio Simeoni ◽  
Nicola Tedeschi
Keyword(s):  
Ground Penetrating Radar ◽  
Analytical Investigation ◽  
Deep Penetration ◽  
Leaky Wave ◽  
New Approach ◽  
Inhomogeneous Waves ◽  
Homogeneous Wave ◽  
Lossy Medium ◽  
Basic Ideas ◽  
Ground Penetrating

Recent studies highlighted deep-penetration prop-erties of inhomogeneous waves at the interface between a loss-less and a lossy medium. Such waves can be generated bymeans of radiating structures known as Leaky-Wave Anten-nas (LWAs). Here, a different approach is proposed basedon the use of a lossy prism capable to generate an inhomo-geneous wave when illuminated by a homogeneous wave. Thelossy prism is conceived and designed thinking of Ground-Penetrating Radar (GPR). The results achieved by the lossyprism will be compared with those obtained by means of a pre-viously designed LWA that was created with the identical ob-jective. The approach of this paper is purely theoretical, andit aims at providing basic ideas and preliminary results usefulfor an innovative LWA design.

New Approach to the Theory of Circular Dichroism

1998 ◽  
Vol 63 (8) ◽  
pp. 1187-1201 ◽  
Author(s):  
Jaroslav Zamastil ◽  
Lubomír Skála ◽  
Petr Pančoška ◽  
Oldřich Bílek
Keyword(s):  
Electromagnetic Wave ◽  
Circular Dichroism ◽  
Electromagnetic Waves ◽  
Maxwell Equations ◽  
Optically Active ◽  
Semiclassical Approach ◽  
New Approach ◽  
Isotropic Media ◽  
New Formula ◽  
Circular Dichroïsm

Using the semiclassical approach for the description of the propagation of the electromagnetic waves in optically active isotropic media we derive a new formula for the circular dichroism parameter. The theory is based on the idea of the time damped electromagnetic wave interacting with the molecules of the sample. In this theory, the Lambert-Beer law need not be taken as an empirical law, however, it follows naturally from the requirement that the electromagnetic wave obeys the Maxwell equations.

A multi-manned assembly line balancing problem with classified teams: a new approach

2016 ◽  
Vol 36 (1) ◽  
pp. 51-59 ◽  
Author(s):  
Hamid Yilmaz ◽  
Mustafa Yilmaz
Keyword(s):  
Design Methodology ◽  
Assembly Line ◽  
Assembly Line Balancing ◽  
Line Balancing ◽  
Test Problems ◽  
New Approach ◽  
Content Type ◽  
Line Test ◽  
Assembly Line Balancing Problem ◽  
First Time

Purpose – Within team-oriented approaches, tasks are assigned to teams before being assigned to workstations as a reality of industry. So it becomes clear, which workers assemble which tasks. Design/methodology/approach – Team numbers of the assembly line can increase with the number of tasks, but at the same time, due to physical situations of the stations, there will be limitations of maximum working team numbers in a station. For this purpose, heuristic assembly line balancing (ALB) procedure is used and mathematical model is developed for the problem. Findings – Well-known assembly line test problems widely used in the literature are solved to indicate the effectiveness and applicability of the proposed approach in practice. Originality/value – This paper draws attention to ALB problem in which workers have been assigned to teams in advance due to the need for specialized skills or equipment on the line for the first time.

A New Approach for the Fabrication of Tetragonal BaTiO3 Nanoparticles

2021 ◽  
Vol 21 (4) ◽  
pp. 2692-2701
Author(s):  
Vu T. Tan ◽  
La The Vinh ◽  
Vu Minh Khoi ◽  
Huynh Dang Chinh ◽  
Pham Van Tuan ◽  
...  
Keyword(s):  
Ferroelectric Properties ◽  
Particle Size Effect ◽  
Ferroelectric Material ◽  
Tem Analysis ◽  
New Approach ◽  
Xrd Pattern ◽  
Munk Function ◽  
Oxide Nanoparticle ◽  
First Time ◽  
Batio3 Nanoparticles

For the first time, the BaTiO3 nano-sized particles were obtained through solid-state reaction by employing the titanium oxide nanoparticle. Meanwhile, by using TiO2 with micro-sized particles, the synthesized BaTiO3 shows the micro-sized. The XRD pattern confirms that both BaTiO3 nano-sized and micro-sized particles display the tetragonal structure. Both SEM and TEM analysis revealed that the size of the nano-sized material is in the range of 30–50 nm; in the meantime, the microsized material shows a size of 500 nm. The Eg of both BaTiO3 micro-sized and nano-sized were calculated by using the Kubelka-Munk function. The shifted bandgap of BaTiO3 nano-sized particle is nearly 0.24 eV larger than that of BaTiO3 miro-sized particle due to the particle size effect. The P-E measurement of n-BaTiO3 proved that the obtained BaTiO3 nano-sized is ferroelectric material. The result may provide a new route for the fabrication of barium titanate nanoparticle with ferroelectric properties.

scholarly journals Exploiting superspace to clarify vacancy and Al/Si ordering in mullite

IUCrJ ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 497-509 ◽  
Author(s):  
Paul Benjamin Klar ◽  
Iñigo Etxebarria ◽  
Gotzon Madariaga
Keyword(s):  
Density Functional ◽  
X Ray Diffraction ◽  
Intrinsic Structure ◽  
Functional Theory ◽  
New Approach ◽  
X Ray ◽  
Vacancy Ordering ◽  
Harmonic Modulation ◽  
First Time

Synchrotron single-crystal X-ray diffraction has revealed diffuse scattering alongside sharp satellite reflections for different samples of mullite (Al4+2xSi2−2xO10−x). Structural models have been developed in (3+1)-dimensional superspace that account for vacancy ordering and Al/Si ordering based on harmonic modulation functions. A constraint scheme is presented which explains the crystal-chemical relationships between the split sites of the average structure. The modulation amplitudes of the refinements differ significantly by a factor of ∼3, which is explained in terms of different degrees of ordering,i.e.vacancies follow the same ordering principle in all samples but to different extents. A new approach is applied for the first time to determine Al/Si ordering by combining density functional theory with the modulated volumes of the tetrahedra. The presence of Si–Si diclusters indicates that the mineral classification of mullite needs to be reviewed. A description of the crystal structure of mullite must consider both the chemical composition and the degree of ordering. This is of particular importance for applications such as advanced ceramics, because the physical properties depend on the intrinsic structure of mullite.

scholarly journals Elephant Herding Optimization for Energy-Based Localization

2018 ◽  
Author(s):  
Sérgio Correia ◽  
Marko Beko ◽  
Luís Cruz ◽  
Slavisa Tomic
Keyword(s):  
Source Localization ◽  
Wireless Sensors ◽  
Performance Comparison ◽  
Sensor Nodes ◽  
Convex Relaxations ◽  
Noisy Environments ◽  
New Approach ◽  
Metaheuristic Methods ◽  
Simulation Results ◽  
First Time

This work addresses the energy-based source localization problem in wireless sensors networks. Instead of circumventing the maximum likelihood (ML) problem by applying convex relaxations and approximations (like all existing approaches do), we here tackle it directly by the use of metaheuristics. To the best of our knowledge, this is the first time that metaheuristics is applied to this type of problems. More specifically an elephant herding optimization (EHO) algorithm is applied. Through extensive simulations, the key parameters of the EHO algorithm are optimized such that they match the energy decay model between two sensor nodes. A detailed analysis of the computational complexity is presented, as well as performance comparison between the proposed algorithm and existing non-metaheuristic ones. Simulation results show that the new approach significantly outperforms the existing solutions in noisy environments, encouraging further improvement and testing of metaheuristic methods.

scholarly journals DISTORTIONLESS SIGNALS TRANSFER THROUGH A WIRE MEDIA METASTRUCTURE

2018 ◽  
Vol 8 (1) ◽  
pp. 44-47 ◽  
Author(s):  
Dmytro Vovchuk ◽  
Serhii Haliuk ◽  
Leonid Politanskyy
Keyword(s):  
Electromagnetic Waves ◽  
Spectral Characteristics ◽  
Wide Frequency Range ◽  
Power Transfer ◽  
Fabry Perot ◽  
Signal Distortions ◽  
Metallic Wires ◽  
The Wire ◽  
Wire Media ◽  
First Time

In the paper the development of the components of communication means is considered based on the wire metastructures. This approach is novel and quite promising due to the metamaterials provides new opportunities for the radio engineering devices such as antennas, absorbers etc. First of all it makes possible decreasing of the dimensions of devices while the characteristics stay the same or better. Here the artificially created metastructure that consists of parallel metallic wires and characterizes by a negative electric permittivity was investigated. The possibility of broadband power transfer of electromagnetic waves was demonstrated. Also, at first time, the investigation of possible signal distortions due to wave propagation through the wire medium (WM) slab was performed via analyzing of spectral characteristics. The obtained results allow applying of WM to power transfer in wide frequency range (not only at frequencies of Fabry-Perot resonant) and enhancement of weak source propagation as well as to antennas constructions due to the absence of signal distortions. One of the promising applications of such structures is the possibility of realizing of flexible screens with nanometer thickness and high resolution.

Imperial Impotence: Treason in 1774 Massachusetts

2011 ◽  
Vol 29 (3) ◽  
pp. 657-701
Author(s):  
Neil L. York
Keyword(s):  
Edmund Burke ◽  
Henry Viii ◽  
House Of Commons ◽  
New Approach ◽  
The Subject ◽  
American Policy ◽  
First Time ◽  
The Way

So contended Edmund Burke in the House of Commons, during a May 1770 speech that ridiculed the government's American policy. It was not the first time Burke raised the subject of this 1543 statute. He had asked—rhetorically—during debates two weeks before, “The Act of Henry VIII. Did you mean to execute that?” He then answered his own question, the scorn beneath it probably apparent to all. “You showed your ill will to America, at the same time you dared not execute it.” Burke hoped that by shaming the ministry he might be able to push through a set of resolutions condemning its policies, which could open the way for a new approach to imperial management. He failed, but that did not mean he had been wrong about the futility of threatening to resurrect an old statute to intimidate protesting Americans.

scholarly journals Theoretical Design and Circuit Implementation of Integer Domain Chaotic Systems

2014 ◽  
Vol 24 (10) ◽  
pp. 1450128 ◽  
Author(s):  
Qianxue Wang ◽  
Simin Yu ◽  
Christophe Guyeux ◽  
Jacques M. Bahi ◽  
Xiaole Fang
Keyword(s):  
Chaotic Systems ◽  
Chaotic Behavior ◽  
Random Sequence ◽  
Noise Signal ◽  
Circuit Implementation ◽  
New Approach ◽  
Uniform Noise ◽  
Definition Of ◽  
First Time ◽  
Hybrid Circuit

In this paper, a new approach for constructing integer domain chaotic systems (IDCS) is proposed, and its chaotic behavior is mathematically proven according to Devaney's definition of chaos. Furthermore, an analog-digital hybrid circuit is also developed for realizing the designed basic IDCS. In the IDCS circuit design, chaos generation strategy is realized through a sample-hold circuit and a decoder circuit so as to convert the uniform noise signal into a random sequence, which plays a key role in circuit implementation. The experimental observations further validate the proposed systematic methodology for the first time.

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