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21 results on '"Faktorová, Dagmar"'

2. Analysis of the Anisotropy of Sound Propagation Velocity in Thin Wooden Plates Using Lamb Waves.

Author

Faktorová, Dagmar, Stanciu, Mariana Domnica, Krbata, Michal, Savin, Adriana, Kohutiar, Marcel, Chlada, Milan, and Năstac, Silviu Marian

Subjects
*ACOUSTIC wave propagation, *SPEED of sound, *LAMB waves, *VARNISH & varnishing, *ANISOTROPY, *WOOD, *RESONANCE
Abstract

The objective of the study was to analyze the influence of coating treatments on sound propagation speeds in thin boards, along the longitudinal and radial directions of resonance wood. The samples studied were thin boards made of spruce and maple wood with dimensions of 240 mm × 80 mm × 4 mm (length × width × thickness) subjected to different coating treatments (oil-based varnish and alcohol varnish) as well as unvarnished samples, exposed to radiation UV, and specimens treated in the saline fog. The test method consisted of evaluating the propagation speeds of Lamb waves applied to thin plates, according to a semicircular test model, so that the results highlighted both the acoustic response in the longitudinal and radial directions as well as the variation in the anisotropy of the samples with the change in the sound propagation direction relative to wood fibers. Based on the statistical analysis, sound propagation speed profiles were obtained in each of the 38 directions analyzed for all wood samples. The results highlighted that the oil-based varnish led to a decrease in the speed of propagation in the radial direction, compared to the alcoholic varnish, whose major effect was in the longitudinal direction, on the spruce wood. On maple wood, increasing the number of varnish layers, regardless of the type of varnish, led to a decrease in the anisotropy ratio between the longitudinal and radial directions. [ABSTRACT FROM AUTHOR]

Published
2024
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6. Application of microwaves on dental diagnose

Author

Papezova, Mária and Faktorová, Dagmar

Subjects
mikrovlnné trouby, dielectric properties, dentální materiál, zubní diagnostika, dental material, dielektrické vlastnosti, microwaves, dental diagnose
Abstract

The aim of our work is to present application of microwaves and compare dielectric properties of dental material without defects in defined frequency range and subsequently comparing properties in defective material as changes in material and classifying the occurrence of inhomogeneities as on the surface so inside the structure.

Published
2015

7. Breast tissue phantom used at microwave frequency range

Author

Luptakova, Eva and Faktorová, Dagmar

Subjects
body regions, microwave range, přízrak, cancer, mikrovlnný rozsah, equipment and supplies, breast, rakovina, prsa
Abstract

Breast cancer is the most common type of cancer in women in developing and developed countries. Research is ongoing to continually improve cancer treatment success and elimination of side effects. Research has often used tissue phantoms that simulate those of the actual tissue. Article we designed a phantom breast and phantom tumour, which can be used for measurements in the microwave frequency range.

Published
2015

8. Microwave Nondestructive Testing of Dielectric Materials

Author

Faktorová, Dagmar

Subjects
Dielectric materials, NDT, microwave signal, Electrical engineering. Electronics. Nuclear engineering, lcsh:Electrical engineering. Electronics. Nuclear engineering, lcsh:TK1-9971, TK1-9971
Abstract

The article focuses on measurements on pertinax and polyethylene samples to obtain their material characteristics by means of microwave investigation. Evaluation of the results is performed and accuracy possibilities are discussed. The influence of free holes and longitudinal cracks in pertinax on the reflected microwave signal is investigated.Also in the same way holes in teflon sample filled with the metal powder are irradiated with microwaves and the reflected signal is followed up. The measuring results are plotted in graphs. Also some comparisons of NDT methods are given.

Published
2006

9. Optimization of Mild Microwave Hyperthermia Interconnection with Targeted Delivery of Nanoparticles

Author

Faktorová, Dagmar and Pápežová, Mária

Subjects
liposomes, liposomy, drug delivery, microwave hyperthermia, nanoparticles, nanočástice, řízené uvolňování léčiv z lékových forem, mikrovlnná hypertermie
Abstract

The paper deals with interconnection of microwave hyperthermia with controlled biodistribution of nanoparticles in order to maximize the exposure tumorous tissue and minimize heating the neighbouring healthy tissue. We investigated in our research the delivering nanoparticles to the tumorous tissue as a function of time in order to optimize the beginning of microwave hyperthermia treatment. We also follow the other parameters which could affect the effect process of microwave hyperthermia.

Published
2013

10. Investigation of metamaterial structure influence on selective properties of microwave waveguide sensor

Author

Isteníková, Katarína, Faktorová, Dagmar, and Kropík, Petr

Subjects
komplexní permitivita, stop-pásmový filtr, microwave sensor, Physics::Optics, senzor mikrovlnné trouby, Physics::Classical Physics, complex permittivity, stop-band filter
Abstract

The paper proposes the possibility of metamaterial structure using for the transmission properties of open waveguide probe changing and the possibility of microwave open waveguide sensor tuning with metamaterial structure to be used for nondestructive testing of dielectric materials properties. The aim of our work was to develop a frequency selective sensor in microwave frequency band sensitive to changing of dielectric properties of investigated dielectric material. In the paper we describe the new approach with incorporation metamaterial structures with negative permittivity and permeability in the volume of waveguide sensor in order to create the stop-band properties of designed sensor. The optimal number of metamaterial units and metamaterial structures inserted into waveguide volume were numerically optimized and experimentally verified for chosen frequency band from microwave frequencies region.

Published
2011

11. Unambiguous Assessment of Solid Materials Dielectric Constant at Microwave Frequencies

Author

Faktorová, Dagmar, Isteníková, Katarína, Pihera, Josef, and Steiner, František

Subjects
Condensed Matter::Materials Science, solid materials, carbon admixture, dielectric properties, dielectric constant, dielectric materials, Physics::Optics, dielektrické materiály, uhlíkové příměsy, pevné materiály, dielektrické vlastnosti, dielektrická konstanta
Abstract

The paper presents the effect of carbon powder admixture added to the volume of dielectric slab at its absorbingproperties. A practical method for dielectric constant determination with fully unknown dielectric properties of new material formed from basic dielectric material and carbon admixture is given. Very simple and wellknown theoretical formulae are used for unambiguous determination at the complex permittivity calculation. Experimental results are presented, too.

Published
2010

12. Dielectric spectroscopy of glucose turnover in cancerous tissue model

Author

Faktorová, Dagmar and Karban, Pavel

Subjects
karcinom tkáně, glukóza, dielectric properties, mikrovlnné kmitočty, dielektrická spektroskopie, carcinoma tissue, Warburg effect, Warburgův efekt, glucose, dielektrické vlastnosti, microwave frequencies, dielectric spectroscopy
Abstract

The article focuses on dielectric spectroscopy, measurement and calculation of dielectric properties of normal and carcinoma tissue phantoms. Special attention is paid to the investigation of dielectric properties of carcinoma tissue model with different water and glucose content. The paper devotes itself to investigation of dielectric qualities of pure glucose, glucose in solutions as well as in phantoms of biological tissues directing the attention at its manifestation at tumours cells investigation by means of microwaves. Experimental results from these areas are given and their evaluation is presented.

Published
2009

13. Numerical modelling of electromagnetic wave interaction with heterogeneous biological structure

Author

Faktorová, Dagmar, Zrník, Juraj, and Karban, Pavel

Subjects
vrstvená struktura, reflection coefficient, transmission coefficient, mikrovlnné kmitočty, součinitel prostupu, činitel odrazu, biological tissue, biologické tkáně, microwave frequencies, layered structure
Abstract

The paper presents a numerical modeling of electromagnetic wave interaction with planar layered structure through reflection and transmission coefficient at boundaries of two biological tissues. Numerical calculation both reflection and transmission coefficients at boundaries is investigated with respect to the multiple reflections of planar electromagnetic wave at boundaries and with the respect to the transmission of reflected wave between two layers represented by fat and muscle with known dielectric properties. In our paper we presented the frequency dependence of reflection and transmission coefficient over the microwave frequency range from 1 GHz to 30 GHz and also the influence of fat layer thickness at investigated coefficients.

Published
2009

14. Application of short circuit waveguide method for evaluation of inhomogenities in dielectric sample

Author

Faktorová, Dagmar, Pihera, Josef, and Steiner, František

Subjects
mikrovlnná diagnostika, kompozit, dielektrika, composite, microwave diagnostics, dielectric, testování materiálů, material testing
Abstract

In the paper main consideration is paid to investigation of inhomogenities in dielectric sample from the standpoint of their impedance properties and reflected signal amplitude. Such application include inspecting modern materials such as composites, detecting and characterizing surface and volume flaws, and evaluating the compressive strength of cement structures.The paper deals with measurement of reflex coefficient in dependence on crack depth on dielectric samples on microwave frequencies from the X –band. Evaluations are made by means of quantities used in microwave technique. Obtained quantities are compared with each other and also with analogous to the quantities measured at the same conditions on metal sample.

Published
2008

15. Utilization of microwaves at material defects investigation

Author

Faktorová, Dagmar and Ulrych, Bohuš

Subjects
nedestruktivní testování, mikrovlnné trouby, vlnovod, crack, trhlina, non-destructive testing, rust, rez, waveguides, microwaves
Abstract

The paper describes microwave measurement of metal defects using the relevant theoretical assumptions. The cracks are judged from the point of view microwave practice and waveguide technique and formulae are exploited. Measurement results are plotted in graphs and discussed.

Published
2007

18. Microwave Resonant Methods for Bone Replacement Biomaterials Testing.

Author

Faktorová, Dagmar, Pápežová, Mária, Savin, Adriana, Steigmann, Rozina, Nový, František, and Bokuvka, Otakar

Subjects
*BONE substitutes, *BIOMATERIALS, *FRACTURE mechanics, *MICROWAVE frequency converters, *GRAPH theory, *RATIO measurement
Abstract

The purpose of this work was to find out to what extent the knowledge of dependence of impedance on the crack depth observed by means of microwave frequencies can be used as noninvasive techniques for biocompatible materials which are used in bone replacement. Primary quantity usable for this assessment was the reflection coefficient obtained from the standing wave ratio measurement. The measured and calculated results are given in the graphic form and are compared each other in common graphs which provide a good overview about basic quantities and simultaneously give an initiative for orientation on practical applications in the process of defect presence finding in materials used in bone replacement. [ABSTRACT FROM AUTHOR]

Published
2014
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21. IDENTIFICATION OF THE BREAKDOWN AND ANALYSIS OF TRANSFORMER 22/0.4 KV.

Author

Brandt, Martin, Faktorová, Dagmar, and Seewald, Róbert

Subjects
ELECTRIC resonators, POWER transformers, ELECTRIC breakdown, FREQUENCY response, ELECTRIC generators, ELECTRIC windings
Abstract

The paper deals with the identification of the breakdown of the transformer withdrawn from operation because of repeated reaction of transformer protections. Successively the transformer was put of operation, removed from the distribution and put to diagnostic measurements. For identification of the failure were used diagnostic methods, e.g. Sweep Frequency Response Analysis (according to IEC 60076-18), measurement of winding resistances, measurement of isolation resistances and capacitances. The results were compared with reference measurements. [ABSTRACT FROM AUTHOR]

Published
2013

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