MONITORING THE PEAK FREQUENCY OF SCHUMANN RESONANCE AND ANALEMMA

Abstract The more precise determination of instantaneous peak frequency of Schumann resonance (SR) modes, especially based on relatively short signal sequences, seems to be important for detailed analysis of SR modal frequencies variations. Contrary to commonly used method of obtaining modal frequencies by Lorentzian fitting of DFT spectra, the attempt was made to employ the complex demodulation method in iterated form. The results for SR signals contaminated with low-frequency noise and hum in various degree as well as the comparison with standard method are presented. Real signals of vertical electric field component picked up at the Astronomical and Geophysical Observatory of Comenius University at Modra, Slovakia, were the primary sources.

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Evaluation of the linkage between Schumann Resonance peak frequency values and global and regional temperatures

Climate Research ◽

10.3354/cr016031 ◽

2000 ◽

Vol 16 ◽

pp. 31-36 ◽

Cited By ~ 5

Author(s):

RC Balling ◽

M Hildebrand

Keyword(s):

Peak Frequency ◽

Resonance Peak ◽

Schumann Resonance

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Anomalous effect in Schumann resonance phenomena observed in Japan, possibly associated with the Chi-chi earthquake in Taiwan

Annales Geophysicae ◽

10.5194/angeo-23-1335-2005 ◽

2005 ◽

Vol 23 (4) ◽

pp. 1335-1346 ◽

Cited By ~ 50

Author(s):

M. Hayakawa ◽

K. Ohta ◽

A. P. Nickolaenko ◽

Y. Ando

Keyword(s):

Frequency Shift ◽

Main Shock ◽

Peak Frequency ◽

Resonance Mode ◽

Resonance Phenomenon ◽

Meridian Plane ◽

Schumann Resonance ◽

Anomalous Effect ◽

Arrival Angle ◽

Small Magnitude

Abstract. The Schumann resonance phenomenon has been monitored at Nakatsugawa (near Nagoya) in Japan since the beginning of 1999, and due to the occurance of a severe earthquake (so-called Chi-chi earthquake) on 21 September 1999 in Taiwan we have examined our Schumann resonance data at Nakatsugawa during the entire year of 1999. We have found a very anomalous effect in the Schumann resonance, possibly associated with two large land earthquakes (one is the Chi-chi earthquake and another one on 2 November 1999 (Chia-yi earthquake) with a magnitude again greater than 6.0). Conspicuous effects are observed for the larger Chi-chi earthquake, so that we summarize the characteristics for this event. The anomaly is characterized mainly by the unusual increase in amplitude of the fourth Schumann resonance mode and a significant frequency shift of its peak frequency (~1.0Hz) from the conventional value on the By magnetic field component which is sensitive to the waves propagating in the NS meridian plane. Anomalous Schumann resonance signals appeared from about one week to a few days before the main shock. Secondly, the goniometric estimation of the arrival angle of the anomalous signal is found to coincide with the Taiwan azimuth (the unresolved dual direction indicates toward South America). Also, the pulsed signals, such as the Q-bursts, were simultaneously observed with the "carrier" frequency around the peak frequency of the fourth Schumann resonance mode. The anomaly for the second event for the Chia-yi earthquake on 2 November had much in common. But, most likely due to a small magnitude, the anomaly appears one day before and lasts until one day after the main shock, with the enhancement at the fourth Schumann resonance mode being smaller in amplitude than the case of the Chi-chi earthquake. Yet, the other characteristics, including the goniometric direction finding result, frequency shift, etc., are nearly the same. Although the emphasis of the present study is made on experimental aspects, a possible generation mechanism for this anomaly is discussed in terms of the ELF radio wave scattered by a conducting disturbance, which is likely to take place in the middle atmosphere over Taiwan. Model computations show that the South American thunderstorms (Amazon basin) play the leading role in maintaining radio signals, leading to the anomaly in the Schumann resonance.

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Extending Dynamic Range and Evaluating Method for Measuring Degree of Red Blood Cell Aggregation with Ultrasonic Peak Frequency

IEEJ Transactions on Electronics Information and Systems ◽

10.1541/ieejeiss.139.636 ◽

2019 ◽

Vol 139 (5) ◽

pp. 636-637

Author(s):

Takayuki Sato ◽

Keita Suzuki

Keyword(s):

Blood Cell ◽

Red Blood Cell ◽

Dynamic Range ◽

Cell Aggregation ◽

Peak Frequency ◽

Red Blood Cell Aggregation ◽

Evaluating Method ◽

Blood Cell Aggregation

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Terahertz and Microwave Optical Properties of Single-Crystal Quartz and Vitreous Silica and the Behavior of the Boson Peak

Applied Sciences ◽

10.3390/app11156733 ◽

2021 ◽

Vol 11 (15) ◽

pp. 6733

Author(s):

Mira Naftaly ◽

Andrew Gregory

Keyword(s):

Single Crystal ◽

Silica Glass ◽

Broad Band ◽

Peak Frequency ◽

Vitreous Silica ◽

Peak Height ◽

Fused Silica ◽

Boson Peak ◽

Single Crystal Quartz ◽

Crystal Quartz

Z-cut single-crystal quartz and vitreous silica (silica glass or fused silica) were evaluated for use as reference materials for terahertz and microwave measurements of complex permittivity, with Z-cut quartz confirmed as being suitable. Measurements of refractive indices and absorption coefficients for o-ray and e-ray in quartz and for vitreous silica are reported at frequencies between 0.2 and 6 THz and at 36 and 144 GHz, and compared with data reported in the literature. A previously unreported broad band was seen in the extraordinary absorption of quartz. The Boson peak in silica glass absorption was examined, and for the first time, two negative relationships have been observed: between the refractive index and the Boson peak frequency, and between the Boson peak height and its frequency.

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Individual Alpha Peak Frequency, an Important Biomarker for Live Z-Score Training Neurofeedback in Adolescents with Learning Disabilities

Brain Sciences ◽

10.3390/brainsci11020167 ◽

2021 ◽

Vol 11 (2) ◽

pp. 167

Author(s):

Rubén Pérez-Elvira ◽

Javier Oltra-Cucarella ◽

José Antonio Carrobles ◽

Minodora Teodoru ◽

Ciprian Bacila ◽

...

Keyword(s):

Learning Disabilities ◽

Pediatric Population ◽

Peak Frequency ◽

Normative Values ◽

Z Score ◽

Absolute Power ◽

The Individual ◽

And Behavior ◽

The Waves ◽

Alpha Peak

Learning disabilities (LDs) have an estimated prevalence between 5% and 9% in the pediatric population and are associated with difficulties in reading, arithmetic, and writing. Previous electroencephalography (EEG) research has reported a lag in alpha-band development in specific LD phenotypes, which seems to offer a possible explanation for differences in EEG maturation. In this study, 40 adolescents aged 10–15 years with LDs underwent 10 sessions of Live Z-Score Training Neurofeedback (LZT-NF) Training to improve their cognition and behavior. Based on the individual alpha peak frequency (i-APF) values from the spectrogram, a group with normal i-APF (ni-APF) and a group with low i-APF (li-APF) were compared in a pre-and-post-LZT-NF intervention. There were no statistical differences in age, gender, or the distribution of LDs between the groups. The li-APF group showed a higher theta absolute power in P4 (p = 0.016) at baseline and higher Hi-Beta absolute power in F3 (p = 0.007) post-treatment compared with the ni-APF group. In both groups, extreme waves (absolute Z-score of ≥1.5) were more likely to move toward the normative values, with better results in the ni-APF group. Conversely, the waves within the normal range at baseline were more likely to move out of the range after treatment in the li-APF group. Our results provide evidence of a viable biomarker for identifying optimal responders for the LZT-NF technique based on the i-APF metric reflecting the patient’s neurophysiological individuality.

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Frequency Variability Feature for Life Signs Detection and Localization in Natural Disasters

Remote Sensing ◽

10.3390/rs13040796 ◽

2021 ◽

Vol 13 (4) ◽

pp. 796

Author(s):

Long Zhang ◽

Xuezhi Yang ◽

Jing Shen

Keyword(s):

Natural Disasters ◽

Current Method ◽

Peak Frequency ◽

Significant Information ◽

Physiological Phenomenon ◽

In The Wild ◽

Motion Magnification ◽

Background Motion ◽

Detection And Localization ◽

Frequency Properties

The locations and breathing signal of people in disaster areas are significant information for search and rescue missions in prioritizing operations to save more lives. For detecting the living people who are lying on the ground and covered with dust, debris or ashes, a motion magnification-based method has recently been proposed. This current method estimates the locations and breathing signal of people from a drone video by assuming that only human breathing-related motions exist in the video. However, in natural disasters, background motions, such as swing trees and grass caused by wind, are mixed with human breathing, that distort this assumption, resulting in misleading or even no life signs locations. Therefore, the life signs in disaster areas are challenging to be detected due to the undesired background motions. Note that human breathing is a natural physiological phenomenon, and it is a periodic motion with a steady peak frequency; while background motion always involves complex space-time behaviors, their peak frequencies seem to be variable over time. Therefore, in this work we analyze and focus on the frequency properties of motions to model a frequency variability feature used for extracting only human breathing, while eliminating irrelevant background motions in the video, which would ease the challenge in detection and localization of life signs. The proposed method was validated with both drone and camera videos recorded in the wild. The average precision measures of our method for drone and camera videos were 0.94 and 0.92, which are higher than that of compared methods, demonstrating that our method is more robust and accurate to background motions. The implications and limitations regarding the frequency variability feature were discussed.

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Research on the Dynamic Responses of Simply Supported Horizontal Pipes Conveying Gas-Liquid Two-Phase Slug Flow

Processes ◽

10.3390/pr9010083 ◽

2021 ◽

Vol 9 (1) ◽

pp. 83

Author(s):

Gang Liu ◽

Zongrui Hao ◽

Yueshe Wang ◽

Wanlong Ren

Keyword(s):

Slug Flow ◽

Peak Frequency ◽

Dynamic Responses ◽

Piping System ◽

Transverse Displacement ◽

Vibration Acceleration ◽

Two Phase ◽

Horizontal Pipes ◽

Simply Supported ◽

Superficial Gas Velocity

The dynamic responses of simply supported horizontal pipes conveying gas-liquid two-phase slug flow are explored. The intermittent characteristics of slug flow parameters are mainly considered to analyze the dynamic model of the piping system. The results show that the variations of the midpoint transverse displacement could vary from periodic-like motion to a kind of motion whose amplitude increases as time goes on if increasing the superficial gas velocity. Meanwhile, the dynamic responses have certain relations with the vibration acceleration. By analyzing the parameters in the power spectrum densities of vibration acceleration such as the number of predominant frequencies and the amplitude of each peak frequency, the dynamic behaviors of the piping system like periodicity could be calculated expediently.

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Evaluation of non-thermal effect of microwave radiation and its mode of action in bacterial cell inactivation

Scientific Reports ◽

10.1038/s41598-021-93274-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Priyanka Shaw ◽

Naresh Kumar ◽

Sohail Mumtaz ◽

Jun Sup Lim ◽

Jung Hyun Jang ◽

...

Keyword(s):

Thermal Effect ◽

Microwave Radiation ◽

Bacterial Cell ◽

Mode Of Action ◽

Surface Damage ◽

Peak Frequency ◽

Viable Count ◽

Bacterial Inactivation ◽

Bacterial Strains ◽

Log Reduction

AbstractA growing body of literature has recognized the non-thermal effect of pulsed microwave radiation (PMR) on bacterial systems. However, its mode of action in deactivating bacteria has not yet been extensively investigated. Nevertheless, it is highly important to advance the applications of PMR from simple to complex biological systems. In this study, we first optimized the conditions of the PMR device and we assessed the results by simulations, using ANSYS HFSS (High Frequency Structure Simulator) and a 3D particle-in-cell code for the electron behavior, to provide a better overview of the bacterial cell exposure to microwave radiation. To determine the sensitivity of PMR, Escherichia coli and Staphylococcus aureus cultures were exposed to PMR (pulse duration: 60 ns, peak frequency: 3.5 GHz) with power density of 17 kW/cm2 at the free space of sample position, which would induce electric field of 8.0 kV/cm inside the PBS solution of falcon tube in this experiment at 25 °C. At various discharges (D) of microwaves, the colony forming unit curves were analyzed. The highest ratios of viable count reductions were observed when the doses were increased from 20D to 80D, which resulted in an approximate 6 log reduction in E. coli and 4 log reduction in S. aureus. Moreover, scanning electron microscopy also revealed surface damage in both bacterial strains after PMR exposure. The bacterial inactivation was attributed to the deactivation of oxidation-regulating genes and DNA damage.

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