scholarly journals A Novel Technology for Measurements of Dielectric Properties of Extremely Small Volumes of Liquids

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Wei-Na Liu
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Radio Frequency ◽  
Transmission Coefficient ◽  
Biological Samples ◽  
Spectroscopic Analysis ◽  
High Sensitivity ◽  
Quantitative Measurements ◽  
Novel Technology ◽  
The Relationship

A high sensitivity sensor for measurement radio frequency (RF) dielectric permittivity of liquids is described. Interference is used and parasitic effects are cancellation, which makes the sensor can catch weak signals caused by liquids with extremely small volumes. In addition, we present the relationship between transmission coefficient and permittivity of liquids under test (LUT). Using this sensor, quantitative measurements of the dielectric properties at 5.8 GHz are demonstrated of LUTs. Experiments show that the proposed method only requires the volume of 160 nanoliters for liquids. Therefore, the technology can be used for RF spectroscopic analysis of biological samples and extremely precious liquids.

A pore-size scale model for the dielectric properties of water-saturated clean rocks and soils

Geophysics ◽  
2006 ◽  
Vol 71 (6) ◽  
pp. F185-F193 ◽  
Author(s):  
Anthony L. Endres ◽  
Edward A. Bertrand
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Pore Space ◽  
Relative Size ◽  
Scale Model ◽  
Size Scale ◽  
Saturated Rock ◽  
Water Saturated ◽  
Free Media ◽  
The Relationship

The dielectric properties of water-saturated rock and soils are strongly dependent on the amount and nature of their porosity; interpretation of these geophysical data requires petrophysical models that incorporate both of these elements. The differential effective medium approximation (DEMA) is used to develop a dielectric permittivity model for clean (i.e., clay free) media that divides the pore spaces into elements corresponding to three categories of relative size scale: microscopic porosity (e.g., intergranular cracks), mesoscopic porosity (e.g., main pore volumes), and macroscopic porosity (e.g., vugs and fractures). The hierarchical size-scale structure imposed by the DEMA iterative embedding process is used to assign each pore space category its role in model construction. Use of this model demonstrates that the relationship between dielectric permittivity and porosity is significantly affected by the size scales of pores present in the rock models. A region of realizable permittivity-porosity values is obtained by varying the pore structure in the scaled-porosity model. The bounds of this region correspond to end-member porosity models. Analysis of experimental permittivity data for water-saturated sandstones and carbonates that cover a substantial range of porosity values found that the scaled-porosity models account for a significant part of the variability in experimental data.

Biological effects of low-intensity radiofrequency fields and risk assessment for biota

2020 ◽  
Vol 60 (9) ◽  
pp. 592-596
Author(s):  
Elena I. Sarapultseva ◽  
Darya V. Uskalova ◽  
Ksenya V. Ustenko
Keyword(s):  
Radio Frequency ◽  
Electromagnetic Radiation ◽  
Electromagnetic Fields ◽  
Negative Impact ◽  
Biological Effects ◽  
High Sensitivity ◽  
Communication Technologies ◽  
Natural Ecosystems ◽  
Low Intensity ◽  
Different Levels

Despite the fact that there are still conflicting opinions about the damage caused by modern wireless communication technologies, most scientists report on the negative biological effects of low-intensity radio frequency electromagnetic radiation at different levels of the organization of live nature. There is no doubt that there is a need not only for a sanitary and hygienic assessment of man-made electromagnetic effects on humans, but also for an environmental assessment for biota. The purpose of the study was to assess the potential environmental risk of electromagnetic impact in the centimeter range on natural ecosystems. The initial data were the authors' own results in the field of radiobiology of non-ionizing radiation, as well as published of other researchers. The article analyzes the biological effects of radio frequency electromagnetic fields detected in organisms of different systematic groups and levels of organization. The data on the non-thermal biological effects of electromagnetic fields indicate a high sensitivity of different species to this factor. The analyzed research results emphasize the need to take into account the features of non-thermal effects of electromagnetic radiation on biota, since these radiations can have a negative impact on different hierarchical levels in natural ecosystems.

Destruction of water-in-oil emulsions in electromagnetic fields in a dynamic mode

2012 ◽  
Vol 9 (1) ◽  
pp. 110-115
Author(s):  
L.A. Kovaleva ◽  
R.R. Zinnatullin ◽  
V.N. Blagochinnov ◽  
A.A. Musin ◽  
Yu.I. Fatkhullina ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Radio Frequency ◽  
Electromagnetic Fields ◽  
Dynamic Mode ◽  
Droplet Dynamics ◽  
Oil Emulsion ◽  
Numerical Studies ◽  
Em Field ◽  
Oil Emulsions ◽  
Water In Oil Emulsion

Some results of experimental and numerical studies of the influence of radio-frequency (RF) and microwave (MW) electromagnetic (EM) fields on water-in-oil emulsions are presented. A detailed investigation of the dependence of the dielectric properties of emulsions on the frequency of the field makes it possible to establish the most effective frequency range of the EM influence. The results of water-in-oil emulsion stability in the RF EM field depending on their dielectric properties are presented. The effect of the MW EM field on the emulsion in a dynamic mode has been studied experimentally. In an attempt to understand the mechanism of emulsion destruction the mathematical model for a single emulsion droplet dynamics in radio-frequency (RF) and microwave (MW) electromagnetic fields is formulated.

scholarly journals Sintering, Microstructure, and Dielectric Properties of Copper Borates for High Frequency LTCC Applications

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4017
Author(s):  
Dorota Szwagierczak ◽  
Beata Synkiewicz-Musialska ◽  
Jan Kulawik ◽  
Norbert Pałka
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
High Frequency ◽  
Ceramic Materials ◽  
Sintering Behavior ◽  
Terahertz Time Domain Spectroscopy ◽  
Very High Frequency ◽  
X Ray ◽  
Low Dielectric ◽  
Very High

New ceramic materials based on two copper borates, CuB2O4 and Cu3B2O6, were prepared via solid state synthesis and sintering, and characterized as promising candidates for low dielectric permittivity substrates for very high frequency circuits. The sintering behavior, composition, microstructure, and dielectric properties of the ceramics were investigated using a heating microscope, X-ray diffractometry, scanning electron microscopy, energy dispersive spectroscopy, and terahertz time domain spectroscopy. The studies revealed a low dielectric permittivity of 5.1–6.7 and low dielectric loss in the frequency range 0.14–0.7 THz. The copper borate-based materials, owing to a low sintering temperature of 900–960 °C, are suitable for LTCC (low temperature cofired ceramics) applications.

scholarly journals Elevated circulating FABP4 concentration predicts cardiovascular death in a general population: a 12-year prospective study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Norie Saito ◽  
Masato Furuhashi ◽  
Masayuki Koyama ◽  
Yukimura Higashiura ◽  
Hiroshi Akasaka ◽  
...  
Keyword(s):  
General Population ◽  
High Sensitivity ◽  
Cardiovascular Death ◽  
Population Based ◽  
Causal Link ◽  
Fatty Acid Binding ◽  
Reactive Protein ◽  
Cox Proportional Hazard ◽  
Kaplan Meier ◽  
The Relationship

AbstractFatty acid-binding protein 4 (FABP4) is secreted from adipose tissue and acts as an adipokine, and an elevated circulating FABP4 level is associated with metabolic disorders and atherosclerosis. However, little is known about the causal link between circulating FABP4 level and mortality in a general population. We investigated the relationship between FABP4 concentration and mortality including cardiovascular death during a 12-year period in subjects of the Tanno-Sobetsu Study, a population-based cohort (n = 721, male/female: 302/419). FABP4 concentration at baseline was significantly higher in female subjects than in male subjects. All-cause death occurred in 123 (male/female: 74/49) subjects, and 34 (male/female: 20/14) and 42 (male/female: 26/16) subjects died of cardiovascular events and cancer, respectively. When divided into 3 groups according to tertiles of FABP4 level at baseline by sex (T1–T3), Kaplan–Meier survival curves showed that there were significant differences in rates of all-cause death and cardiovascular death, but not cancer death, among the groups. Multivariable Cox proportional hazard model analysis with a restricted cubic spline showed that hazard ratio (HR) for cardiovascular death, but not that for all-cause death, significantly increased with a higher FABP4 level at baseline after adjustment of age and sex. The risk of cardiovascular death after adjustment of age, sex, body mass index and levels of brain natriuretic peptide and high-sensitivity C-reactive protein in the 3rd tertile (T3) group (HR: 4.96, 95% confidence interval: 1.20–22.3) was significantly higher than that in the 1st tertile (T1) group as the reference. In conclusion, elevated circulating FABP4 concentration predicts cardiovascular death in a general population.

Carotenes and carotenoids in natural biological samples: a Raman spectroscopic analysis

2009 ◽  
Vol 41 (6) ◽  
pp. 642-650 ◽  
Author(s):  
Vanessa E. de Oliveira ◽  
Harlem V. Castro ◽  
Howell G. M. Edwards ◽  
Luiz Fernando C. de Oliveira
Keyword(s):  
Biological Samples ◽  
Spectroscopic Analysis ◽  
Raman Spectroscopic ◽  
Raman Spectroscopic Analysis

scholarly journals Polytetrafluoroethylene Films in Rigid Polyurethane Foams’ Dielectric Permittivity Measurements with a One-Side Access Capacitive Sensor

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1173
Author(s):  
Ilze Beverte ◽  
Ugis Cabulis ◽  
Sergejs Gaidukovs
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Low Frequency ◽  
Capacitive Sensor ◽  
Polyurethane Foams ◽  
Active Area ◽  
Ptfe Film ◽  
Practical Applications ◽  
Permittivity Measurements ◽  
The Impact

As a non-metallic composite material, widely applied in industry, rigid polyurethane (PUR) foams require knowledge of their dielectric properties. In experimental determination of PUR foams’ dielectric properties protection of one-side capacitive sensor’s active area from adverse effects caused by the PUR foams’ test objects has to be ensured. In the given study, the impact of polytetrafluoroethylene (PTFE) films, thickness 0.20 mm and 0.04 mm, in covering or simulated coating the active area of one-side access capacitive sensor’ electrodes on the experimentally determined true dielectric permittivity spectra of rigid PUR foams is estimated. Penetration depth of the low frequency excitation field into PTFE and PUR foams is determined experimentally. Experiments are made in order to evaluate the difference between measurements on single PUR foams’ samples and on complex samples “PUR foams + PTFE film” with two calibration modes. A modification factor and a small modification criterion are defined and values of modifications are estimated in numerical calculations. Conclusions about possible practical applications of PTFE films in dielectric permittivity measurements of rigid PUR foams with one-side access capacitive sensor are made.

Word Fluency Test Performance in Primary Progressive Aphasia and Primary Progressive Apraxia of Speech

2021 ◽  
pp. 1-8
Author(s):  
Lucia Scheffel ◽  
Joseph R. Duffy ◽  
Edythe A. Strand ◽  
Keith A. Josephs
Keyword(s):  
Test Performance ◽  
Primary Progressive Aphasia ◽  
High Sensitivity ◽  
Clinical Group ◽  
Apraxia Of Speech ◽  
Word Fluency ◽  
Progressive Aphasia ◽  
Primary Progressive ◽  
The Relationship ◽  
Fluency Task

Purpose This study compared performance on three-word fluency measures among individuals with primary progressive aphasia (PPA) and primary progressive apraxia of speech (PPAOS), and examined the relationship between word fluency and other measures of language and speech. Method This study included 106 adults with PPA and 30 adults with PPAOS. PPA participants were divided into three clinical subgroups: semantic (svPPA), logopenic (lvPPA), and nonfluent/agrammatic with or without apraxia of speech (nfPPA). Category fluency, letter fluency, and action/verb fluency tasks were administered to all participants. Results The four clinical groups performed abnormally on the word fluency measures, although not to a degree that represented high sensitivity to their PPA or PPAOS diagnosis. All PPA subgroups produced fewer words compared to individuals with PPAOS on all word fluency measures. Moderate correlations were found between word fluency and aphasia severity and naming performance in some of the clinical groups. Conclusions Word fluency measures are often challenging for individuals with PPA and PPAOS, but they are not of equal difficulty, with letter fluency being the most difficult. Differences among word fluency tests also vary to some degree as a function of the clinical group in question, with least impairment in PPAOS. However, the findings of this study do not support statistically significant differences in word fluency task performance among the PPA subgroups. Correlations suggest that word fluency performance in PPA is at least partly related to aphasia severity.

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