Course detail

Non-destructive diagnostics and physics of dielectrics

FEKT-MNDDAcad. year: 2015/2016

The course focuses on two areas of modern diagnostic materials, i.e. dielectric spectroscopy and acoustic and electromagnetic emission.
Emphasis is put on the understanding of the issues, applying relevant knowledge and practical experience with diagnostic materials.
The following topics are demonstrated during a semester:
physical laws accompanying the behavior of dielectrics and insulators in electric field polarization happening in dielectrics, the behavior of materials in the DC and AC electric field, the fundamental aspects of conductivity, dielectric absorption, dielectric loss and dielectric strength materials. Furthermore, the basic types of electrical insulating materials due to their being sorted resistance degradation factors, in particular the temperature and electrical stress.
In the area of acoustic and electric emissions will be:
The emergence and spread of acoustic signals and electromagnetic emissions, types of diagnostic sensors, types of defects in composite systems, analysis of noise spectra using low-noise amplifiers, suitable measurement techniques and shielding systems.
Students will enhance skills in diagnostics of materials, analysis of dielectric spectra analysis of noise spectra, programming in Matlab and communication over the GPIB and RS 232

Language of instruction

Czech

Number of ECTS credits

Mode of study

Not applicable.

Guarantor

doc. Ing. Vladimír Holcman, Ph.D.

Department

Department of Physics (UFYZ)

Learning outcomes of the course unit

- Describe different types of polarization in dielectric materials
- Name of the principles of polarization and to estimate the frequency dependence of the dielectric spectrum
- Identify defects in the dielectric systems and identify degradation processes in materials
- Describe the various noise spectrum and assess the impact of noise on the characteristics of the components
- Create a replacement model of passive and active components
- Define the causes of acoustic or electromagnetic emissions and create a mathematical model
- Implement basic acoustic emission measurements
- Create a measurement algorithm in Matlab communication with the GPIB, RS232 and TCP

Prerequisites

Students should be able to explain the basic physical phenomena, analyze simple electronic circuits, know basic programming algorithms in Matlab or C + +.
General knowledge is required at the level of bachelor's degree and valid examination for qualifying workers for an independent activity (within the meaning of § 6 of the Decree).

Co-requisites

Not applicable.

Planned learning activities and teaching methods

Teaching methods depend on the type of course unit as specified in the article 7 of BUT Rules for Studies and Examinations. They include lectures, excercises and practical laboratories. Course is taking advantage of e-learning (Moodle) system.

Assesment methods and criteria linked to learning outcomes

- Evaluation of laboratory exercises - 20 b (total 4 reports)
- Unspecified - 30 b (2 semester work with the defense)
- Final exam - 50 b

Course curriculum

1. Electric fields, induction, introduction to dielectric spectroscopy
2. Dipole moment, dielectric insulator
3. Dielectric polarization in both AC and DC pole
4. The mathematical description of dielectric materials
5. Behavior dielectric spectra depending on the temperature, pressure and humidity
6. Description relaxation processes and their interpretation
7. Acoustic emission, historical development, wave longitudinal, transverse
8. Acoustic emission sensors, instrumentation for measuring acoustic signal.
9. Parameters for assessment, fault isolation.
10. Acoustic emission in composites, acoustic emissions in building materials.
11. Electromagnetic emissions, its interpretation sensor.
12. Methods to increase the immunity measuring systems.

Work placements

Not applicable.

Aims

- Obtain a general overview of the use of dielectric spectroscopy in materials science and other fields of engineering,
- Obtain a general overview of the use of acoustic and electromagnetic emissions in materials science and other fields of engineering,
- Define the basic aspects of the analysis of dielectric materials
- Identify the basic dielectric spectrum and propose a suitable mathematical method
- Define the basic characteristics of the noise
- Identify a characteristic noise and identify corrective measures for passive components
- Create measurement algorithms with conventional measuring instruments on the GPIB, RS232, TCP

Specification of controlled education, way of implementation and compensation for absences

The content and forms of instruction in the evaluated course are specified by a regulation issued by the lecturer responsible for the course and updated for every academic year.

Recommended optional programme components

Not applicable.

Prerequisites and corequisites

Not applicable.

Basic literature

Ambrózy, A.: Electrical Noise, Budapest, Academia, 1982,
Artbauer, J., Šedovic J., Adamec,V.: Izolanty a izolácie, Bratislava, ALFA, 1969,
Böttcher, C. J. F., Bordewijk, P.: Theory of Electric Polarization, 2. ed., Amsterdam, Elsevier, 1978,
Bryknar, Z.: Fyzika dielektrik, Ediční středisko ČVUT, Fakulta jaderná a fyzikálně inženýrská, 1. vyd., Praha, 1983

Type of course unit

Lecture

26 hod., optionally

Teacher / Lecturer

doc. Ing. Vladimír Holcman, Ph.D.
prof. Ing. Pavel Koktavý, CSc. Ph.D.

Syllabus

Types of defects, surface and structural defects, methods of localisation, destructive and non-destructive defects and their identification
Identification of defects from transport characteristics, V-A characteristics v in forward and reverse direction, excess current, generation-recombination process, degradation
Fluctuation processes, noise spectral power density and its correlation with the type of defect, low-frequency noise as reliability and quality indicator, lambda parameter - mean time to failure and its quantification
Noise density in semiconductor devices, noise in homogenous structures and in thin-layer and thick-layer resistors
Partial discharges and noise in insulators and dielectrics, noise in capacitors
Noise in semiconductor lasers, alloy and FET transistors
RTS noise of semiconductor diodes with quantum holes and dots
Theory for the design of a concept of a non-destructive diagnostic test
Phenomenological description of the polarisation
Types of relaxation mechanisms in polymers, glasses and ceramic systems
Mathematical methods for the evaluation of dielectric data
Degradation processes and their observation and monitoring by dielectric methods
Major types of dielectric materials
Main fields of application of dielectric materials and criteria for the selection of dielectrics for individual applications

Fundamentals seminar

13 hod., optionally

Teacher / Lecturer

doc. Ing. Vladimír Holcman, Ph.D.

Syllabus

Basic mathematical tools for the description of fluctuation and transport phenomena, stationarity and ergodicity, momentuses at the time and probability level, correlation function, noise spectral density
Calculation of noise magnitude in individual circuit components, transformation of noise during the transmission of a signal through an electronic system
Elements of diagnostics - size of ensembles and credibility of results, determination of the noise type, calculation of the excess current and of the reliability parameters
Dipol moments of elementary structural units (chemical bonds, molecules) and their calculation, polarisability alfa for atomic and dipole polarisation
Calculation of the local field and trabsition to the ferroelectric state, calculation of the permittivity of dielectric materials from their structure
Transformation from the time domain to the frequency domain and vice versa, Debye model, calculation of the distribution of relaxation times, both analytically and numerically, Hamon approximation, fitting
Ionic polarizations and the calculation of ionic polarizability

Laboratory exercise

13 hod., optionally

Teacher / Lecturer

doc. Ing. Vladimír Holcman, Ph.D.
Ing. Tomáš Trčka, Ph.D.

Syllabus

Measurements of V-A characteristics of semiconductor devices and the determination of their parameters and excess currents
Measurements of the spectral density of a fluctuation (a stochastic process) by both analogue and digital methods
Analysis of noise types from the experimentally found curves
Experimental determination of the dipole moment of nitrobenzene
Measurement of charge and discharge currents of dielectrics and transformation of the time-domain results to the frequency domain via Hamon approximation
Measurement of frequency and temperature dependence of complex permittivity and analysis of the results, determination of the activation energy and co-operativity of the relaxation process

VUT

Faculties

University Institutes

Parts

Non-destructive diagnostics and physics of dielectrics

Type of course unit