Vadim V. Yakovlev

Bio: Vadim V. Yakovlev is an academic researcher from Worcester Polytechnic Institute. The author has contributed to research in topics: Finite-difference time-domain method & Permittivity. The author has an hindex of 14, co-authored 65 publications receiving 500 citations. Previous affiliations of Vadim V. Yakovlev include Russian Academy of Sciences.

Examination of Contemporary Electromagnetic Software Capable of Modeling Problems of Microwave Heating

Abstract: Despite all the progress in numerical mathematics and computational technologies, computer simulation of processes and systems of microwave power engineering remains a new and unexplored arena for most practitioners Engineers dealing with microwave non-communication applications currently seem to lack not specific technical data but general information on modern computational opportunities At the same time, a number of modeling tools do allow one to get valuable data about the characteristics of the considered system prior to constructing a physical prototype The goal of the present paper is to update the database of the modern electromagnetic (EM) software suitable for the modeling of microwave heating and outline a few conceptual and practical issues associated with the efficient use of these simulators

Applicability study of classical and contemporary models for effective complex permittivity of metal powders.

Abstract: Microwave thermal processing of metal powders has recently been a topic of a substantial interest; however, experimental data on the physical properties of mixtures involving metal particles are of...

Waveguide Microwave Imaging: Neural Network Reconstruction of Functional 2-D Permittivity Profiles

Abstract: A new microwave imaging technique is proposed for reconstruction of 2-D complex permittivity profiles in dielectric samples located in a waveguide system. The spatial distributions of the dielectric constant and the loss factor are approximated by continuous functions whose functional parameters are determined using a neural network technique backed by full-wave finite-difference time-domain analysis. The profiles are reconstructed from measurements of reflection and transmission characteristics obtained with the tested sample at different locations. Operational capabilities of the technique are illustrated through a series of computational experiments for rectangular and cylindrical samples at two (original and 90deg -rotated) positions. The results demonstrate excellent agreement between the reconstructed and actual profiles approximated by linear, quadratic, and Gaussian functions: the average relative errors do not exceed 0.4%, 2.2%, and 4.8%, respectively. Finally, the assumption of functional approximation, uniqueness of the reconstruction, and prospects of practical use of the technique are thoroughly discussed.

Determination of complex permittivity with neural networks and FDTD modeling

Abstract: A simple novel cavity-independent method of determination of dielectric properties of arbitrarily shaped materials is presented Complex permittivity is reconstructed using a neural networking procedure matching the measured and FDTD-modeled frequency characteristics of the reflection coefficient High accuracy and practical suitability are demonstrated through numerical testing and determination of dielectric properties of fresh and saline water at 915 MHz © 2004 Wiley Periodicals, Inc Microwave Opt Technol Lett 40: 183–188, 2004; Published online in Wiley InterScience (wwwintersciencewileycom) DOI 101002/mop11323

Efficiency Optimization for Systems and Components in Microwave Power Engineering

Abstract: The paper is concerned with one aspect of optimization of microwave thermal processing, namely, with optimization of energy coupling interpreted as a numerical characteristic of system efficiency. Since in computer-aided design coupling can be evaluated through the computed reflections, an optimization scheme is presented that is particularly suitable for minimizing the reflection coefficient in typical systems and elements of microwave power engineering. Based on response surface methodology and the sequential quadratic programming for constrained optimization, the procedure is linked with the full-wave 3-D FDTD electromagnetic simulator QuickWave-3D. Credibility and effectiveness of the method is illustrated by four examples: dimensional optimization is performed for a dry waveguide load, a waveguide T-junction with a partial-height post, a water cylinder in a cavity, and a slotted waveguide-backed radiating element.

Handbook of Chemistry and Physics

Abstract: There is a special reason for reviewing this book at this time: it is the 50th edition of a compendium that is known and used frequently in most chemical and physical laboratories in many parts of the world. Surely, a publication that has been published for 56 years, withstanding the vagaries of science in this century, must have had something to offer. There is another reason: while the book is a standard fixture in most chemical and physical laboratories, including those in medical centers, it is not as frequently seen in the laboratories of physician's offices (those either in solo or group practice). I believe that the Handbook can be useful in those laboratories. One of the reasons, among others, is that the various basic items of information it offers may be helpful in new tests, either physical or chemical, which are continuously being published. The basic information may relate

Recent Progress on Ferroelectric Polymer-Based Nanocomposites for High Energy Density Capacitors: Synthesis, Dielectric Properties, and Future Aspects.

Abstract: Dielectric polymer nanocomposites are rapidly emerging as novel materials for a number of advanced engineering applications. In this Review, we present a comprehensive review of the use of ferroelectric polymers, especially PVDF and PVDF-based copolymers/blends as potential components in dielectric nanocomposite materials for high energy density capacitor applications. Various parameters like dielectric constant, dielectric loss, breakdown strength, energy density, and flexibility of the polymer nanocomposites have been thoroughly investigated. Fillers with different shapes have been found to cause significant variation in the physical and electrical properties. Generally, one-dimensional and two-dimensional nanofillers with large aspect ratios provide enhanced flexibility versus zero-dimensional fillers. Surface modification of nanomaterials as well as polymers adds flavor to the dielectric properties of the resulting nanocomposites. Nowadays, three-phase nanocomposites with either combination of fillers...

Electrodynamics Of Continuous Media

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Microwave Sintering: Fundamentals and Modeling

Abstract: This paper reviews the basic physical notions underlying microwave sintering and the theoretical and numerical models of the microwave sintering process. The propagation and absorption of electromagnetic waves in materials, and the distribution of electromagnetic field in cavity resonators that serve as applicators for microwave processing are discussed and the electromagnetic modeling of such applicators is reviewed. The microwave absorption properties of ceramic and metal powder materials and the methods of their description are addressed. Self-consistent electromagnetic and thermal models that are capable of predicting the temperature distribution in the microwave-heated materials and dynamic effects such as thermal runaway instabilities are reviewed. The multiphysics simulations that combine electromagnetic, thermal, and sintering models and result in predicting densification, shrinkage, and grain structure evolution are discussed in detail. The significance of microwave nonthermal effects in sintering is demonstrated based on the experimental results, and the models of such effects are reviewed.