Computer Simulation of High‐Frequency Electromagnetic Fields

High‐frequency and microwave electromagnetic fields are used in billions of various devices and systems. Design of these systems is impossible without detailed analysis of their electromagnetic field. Most of microwave systems are very complex, so analytical solution of the field equations for them is impossible. Therefore, it is necessary to use numerical methods of field simulation. Unfortunately, such complex devices as, for example, modern smartphones cannot be accurately analysed by existing commercial codes. The chapter contains a short review of modern numerical methods for Maxwell\u27s equations solution. Among them, a vector finite element method is the most suitable for simulation of complex devices with hundreds of details of various forms and materials, but electrically not too large. The method is implemented in the computer code radio frequency simulator (RFS). The code has friendly user interface, an advanced mesh generator, efficient solver and post‐processor. It solves eigenmode problems, driven waveguide problems, antenna problems, electromagnetic‐compatibility problems and others in frequency domain

Probabilistic Modeling Processes for Oil and Gas

Different uncertainties are researched for providing safe and effective development of hydrocarbon deposits and rational operation of oil and gas systems (OGS). The original models and methods, applicable in education and practice for solving problems of system engineering, are proposed. These models allow us to analyze natural and technogenic threats for oil and gas systems on a probabilistic level for a given prognostic time. Transformation and adaptation of models are demonstrated by examples connected with non-destructive testing. The measures of counteraction to threats for the typical manufacturing processes of gas preparation equipment on enterprise are analyzed. The risks for pipelines, pumping liquefied natural gas across the South American territory, are predicted. Results of probabilistic modeling of the sea gas and oil-producing systems from their vulnerability point of view (including various scenarios of possible terrorist influences) are analyzed and interpreted

НОВЫЙ ВОЛНОВОДНЫЙ МЕТОД ИЗМЕРЕНИЯ ПАРАМЕТРОВ ДИЭЛЕКТРИКОВ

Perfect knowledge of dielectric parameters is necessary for its application in various devices. In spite of the whole range of measurement techniques, their practical implementation in the microwave frequency band runs into some difficulties. This article describes a new method for nonmagnetic dielectrics permittivity and loss tangent measurement in the microwave frequency band. A dielectric specimen slab is placed in the short-circuited waveguide section normal to its axis and fills the whole cross-section of the waveguide at approximately quarter wavelength from its short-circuited endpoint. By means of the vector network analyzer the waveguide section reflection factor is measured. Objective function is de-termined as difference between calculated and measured module and phase of the reflection factor. Specific code for ob-jective function calculation and its minimization is worked out. Minimization of this function by varying dielectric parameters makes it possible to find real values of these parameters. The method needs no de-embedding and can be used with non-calibrated waveguide-to-coax transitions. Also it is less sensitive to the noise component of reflected signal. The testing results show that new method’s error does not exceed 0.2 % for relative permittivity and 1% for dielectric loss tangent.Точное знание параметров диэлектрика необходимо при его применении в самых различных устройствах. Несмотря на наличие целого ряда известных методов измерения этих параметров, практическое их применение в микроволновом диапазоне частот наталкивается на ряд трудностей. В данной статье описан новый волноводный метод измерения диэлектрической проницаемости и тангенса угла потерь немагнитных диэлектриков в микроволновом диапазоне. Пластина диэлектрика помещается в короткозамкнутый отрезок волновода перпендикулярно его оси, заполняя все поперечное сечение на расстоянии примерно четверти длины волны от короткозамкнутого конца отрезка. С помощью векторного анализатора цепей измеряется коэффициент отражения от входа волновода. Для определения параметров диэлектрика по этим данным составлена программа вычисления и минимизации целевой функции, которая определяется как разность между вычисленными значениями модуля и фазы коэффициента отражения на входе волновода и измеренными значениями этого коэффициента. Минимизация этой функции при варьировании параметров диэлектрика позволяет определить указанные параметры. По сравнению с известными, представленный в настоящей статье метод не требует переноса плоскостей отсчета векторного анализатора цепей к поверхностям образца и менее чувствителен к шумовой составляющей измерительного сигнала. Это позволяет использовать при измерении некалиброванные коаксиально-волноводные переходы. По результатам тестирования метода погрешность измерения относительной диэлектрической проницаемости не превышает 0,2 %, а тангенса угла диэлектрических потерь – 1 %

Diagnostic Systems as Basis for Technological Improvement

AbstractHereunder the ways of technical diagnostics in metal manufacturing and peculiarities of challenges which are faced in technical diagnostics are given. The matters of the ways of technical diagnostics, which are required to be solved in near future, are described in the article. Solutions of problems concerning diagnostics of condition of an edge tool, using real-time vibration analysis, are provided. The article says about affect of bearings of spindle units on three-dimensional distribution of vibration parameters. An example concerning a spindle unit that induces auto vibration, which produce a false diagnosis regarding the condition of the edge tool, is given

GROM-RD: Resolving Genomic Biases to Improve Read Depth Detection of Copy Number Variants

Amplifications or deletions of genome segments, known as copy number variants (CNVs), have been associated with many diseases. Read depth analysis of next-generation sequencing (NGS) is an essential method of detecting CNVs. However, genome read coverage is frequently distorted by various biases of NGS platforms, which reduce predictive capabilities of existing approaches. Additionally, the use of read depth tools has been somewhat hindered by imprecise breakpoint identification. We developed GROM-RD, an algorithm that analyzes multiple biases in read coverage to detect CNVs in NGS data. We found non-uniform variance across distinct GC regions after using existing GC bias correction methods and developed a novel approach to normalize such variance. Although complex and repetitive genome segments complicate CNV detection, GROM-RD adjusts for repeat bias and uses a two-pipeline masking approach to detect CNVs in complex and repetitive segments while improving sensitivity in less complicated regions. To overcome a typical weakness of RD methods, GROM-RD employs a CNV search using size-varying overlapping windows to improve breakpoint resolution. We compared our method to two widely used programs based on read depth methods, CNVnator and RDXplorer, and observed improved CNV detection and breakpoint accuracy for GROM-RD. GROM-RD is available a

Development of a formalism of discrete element method to study mechanical response of geological materials and media at different scales

A general approach to realization of models of elasticity, plasticity and fracture of heterogeneous materials within the framework of particle-based discrete element method is proposed in the paper. The approach is based on constructing many-body forces of particle interaction, which provide response of particle ensemble correctly conforming to the response (including elastic-plastic behavior and fracture) of simulated solids. For correct modeling of inelastic deformation and failure of geological materials and media at "high" structural scales (relative to the scale of grains) an implementation of dilatational Nikolaevsky's model of plasticity of rocks within the framework of mathematical formalism of discrete element method is proposed. Perspectives of multiscale modeling of geological materials from grainrelated scale up to macroscopic scale within the same numerical technique (DEM) are discussed