scholarly journals Effects of microwave radiation on living microorganisms: effects and mechanisms

2021 ◽  
Vol 3 (1) ◽  
pp. 75-84
Author(s):  
Tatyana N. Danilchuk ◽  
Kamal М. Alkhateeb
Keyword(s):  
High Frequency ◽  
Food Industry ◽  
Scientific Literature ◽  
Growth Parameters ◽  
Biological Effects ◽  
High Energy ◽  
Frequency Range ◽  
Vital Activity ◽  
Absorbed Energy ◽  
Microwave Exposure

The article analyzes the scientific literature on the effect of microwave exposure on the vital activity of microorganisms. The influence of the frequency of microwaves, the power of the applied impact and the total amount of absorbed energy on the viability of microorganisms and the features of their growth is considered. Possible mechanisms of interaction of microbial cells with the electromagnetic field in the ultrahigh frequency range are considered. It is noted that microorganisms die when exposed to high-energy and high-frequency microwaves, while low-energy and high-frequency microwaves contribute to the intensification of their growth. It is concluded that although many authors observe significant biological effects when exposed to microwaves on living systems, this issue has not been sufficiently studied in the scientific literature. It is of interest to conduct a systematic study of the effect of microwaves of a certain frequency on the biological, biochemical and growth parameters of the cells of microorganisms, in particular lactic acid organisms, in order to use the results of these studies in the food industry in the production of new food products.

scholarly journals The prospects for the application of the electromagnetic waves in the terahertz frequency range for the purpose of physiotherapy (a retrospective review)

2016 ◽  
Vol 15 (4) ◽  
pp. 209-215
Author(s):  
Vera Vasil’evna Kir’yanova ◽  
E. N Zharova ◽  
N. T Bagraev ◽  
A. S Reukov ◽  
S. V Loginova
Keyword(s):  
Electromagnetic Radiation ◽  
Electromagnetic Waves ◽  
Biological Effects ◽  
Physical Factor ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Vital Activity ◽  
Terahertz Frequency Range ◽  
High Biological Activity ◽  
Neurological Conditions

This review of the literature publications is focused on the articles in domestic and foreign editions devoted to the research on biological effects of electromagnetic radiation in the terahertz (THz) frequency range. It makes use of the Scopus, Web of Science, MedLine, RSCI, and other databases containing the relevant references for the period from 1970 up to the present days. This physical factor has found application in the Russian physiotherapeutic practice not very long ago. The main areas of its application include cardiovascular disease and neurological conditions. At the same time. the influence of electromagnetic radiation in the terahertz frequency range on human health and vital activity remains virtually unexplored. The available publications give evidence of the high biological activity of the terahertz electromagnetic waves which suggests the necessity of their further investigation.

scholarly journals A review of accurate phase measurement methods and instruments for sinewave signals

ACTA IMEKO ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 52
Author(s):  
Eulalia Balestrieri ◽  
Luca De Vito ◽  
Francesco Picariello ◽  
Sergio Rapuano ◽  
Ioan Tudosa
Keyword(s):  
Measurement Uncertainty ◽  
High Frequency ◽  
Measurement Method ◽  
Essential Role ◽  
Scientific Literature ◽  
Phase Measurement ◽  
Measurement Methods ◽  
Frequency Range ◽  
Electronic Instrumentation ◽  
Response Testing

<p class="Abstract">The phase measurement of sinewave signals is important in  several applications, such as electric and electronic instrumentation; telecommunications; and optical interferometry. The uncertainty of the phase measurement has an essential role in ensuring the suitable performance of the devices and systems used by the relevant application. Some highly accurate phase measurement methods have been developed and implemented in different instrument types that are currently available on the market or have been proposed in the scientific literature, each capable of covering very different frequency ranges. This article presents an overview of these methods and instruments in order to highlight the characteristics in terms of the measurement uncertainty of the main methods and instruments that are used, by taking into account a varying operative frequency range. The standard deviations considered in the surveyed literature are used to identify a phase measurement method that is capable of covering a large high-frequency range, simultaneously maintaining a low value of measurement uncertainty, as requested by some applications (like waveform recorder frequency response testing).</p>

Evaluation of Special Hearing Aids for Deaf Children

1971 ◽  
Vol 36 (4) ◽  
pp. 527-537 ◽  
Author(s):  
Norman P. Erber
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Low Frequency ◽  
Acoustic Stimulation ◽  
Deaf Children ◽  
Frequency Range ◽  
Frequency Limit ◽  
Unpublished Studies ◽  
Published Research

Two types of special hearing aid have been developed recently to improve the reception of speech by profoundly deaf children. In a different way, each special system provides greater low-frequency acoustic stimulation to deaf ears than does a conventional hearing aid. One of the devices extends the low-frequency limit of amplification; the other shifts high-frequency energy to a lower frequency range. In general, previous evaluations of these special hearing aids have obtained inconsistent or inconclusive results. This paper reviews most of the published research on the use of special hearing aids by deaf children, summarizes several unpublished studies, and suggests a set of guidelines for future evaluations of special and conventional amplification systems.

HIGH FREQUENCY OHMIC LOSSES IN TERAHERTZ FREQUENCY RANGE CW KLYNOTRONS

2017 ◽  
Vol 76 (10) ◽  
pp. 929-940 ◽  
Author(s):  
Yu. S. Kovshov ◽  
S. S. Ponomarenko ◽  
S. A. Kishko ◽  
A. A. Likhachev ◽  
S. A. Vlasenko ◽  
...  
Keyword(s):  
High Frequency ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Terahertz Frequency Range ◽  
Ohmic Losses

Numerical Modelling for Evaluation of Biological Effects Due to High Frequency Radiations in Indoor Environment

PIERS Online ◽  
2010 ◽  
Vol 6 (3) ◽  
pp. 247-251
Author(s):  
Matteo Cacciola ◽  
G. Megali ◽  
Diego Pellicano ◽  
M. Versaci ◽  
Francesco Carlo Morabito
Keyword(s):  
Numerical Modelling ◽  
High Frequency ◽  
Indoor Environment ◽  
Biological Effects

scholarly journals Toxicity and Biological Effects of Beauveria brongniartii Fe0 Nanoparticles against Spodoptera litura (Fabricius)

Insects ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 895
Author(s):  
Jing Xu ◽  
Kaihui Zhang ◽  
Andrew G. S. Cuthbertson ◽  
Cailian Du ◽  
Shaukat Ali
Keyword(s):  
Spodoptera Litura ◽  
Insect Pests ◽  
Growth Parameters ◽  
Uv Spectroscopy ◽  
Biological Effects ◽  
Fungal Treatment ◽  
Beauveria Brongniartii ◽  
Sem Images ◽  
X Ray ◽  
Infection Period

Nanotechnology has clear potential in the development of innovative insecticidal products for the biorational management of major insect pests. Metal-based nanoparticles of different microbial pest control agents have been effective against several pests. Synthesis of Beauveria brongniartii based Fe0 nanoparticles (Fe0NPs) and their bio-efficacy against Spodoptera litura was observed during this study. Beauveria brongniartii conidia were coated with Fe0NPs and characterized by applying a selection of different analytical techniques. Ultraviolet (UV) spectroscopy showed the characteristic band of surface plasmon at 430 nm; Scanning electron microscopy (SEM) images showed spherical shaped nanoparticles with a size ranging between 0.41 to 0.80 µm; Energy-dispersive X-ray (EDX) spectral analysis revealed characteristic Fe peaks at 6.5 and 7.1 Kev; the X-ray diffractogram showed three strong peaks at 2θ values of 45.72°, 64.47°, and 84.05°. The bioassay studies demonstrated that mortality of 2nd instar S. litura larvae following Fe0NPs treatment increased with increasing concentrations of Fe0NPs at different time intervals. The median lethal concentration (LC50) values of Fe0NPs against S. litura after seven days of fungal treatment was 59 ppm, whereas median survival time (LT50) values for 200 and 500 ppm concentrations of Fe0NPs against S. litura seven days post-treatment were 5.1 and 2.29 days, respectively. Beauveria brongniartii-Fe0NPs caused significant reductions in feeding and growth parameters (relative growth rate, relative consumption rate, and efficiency of conversion of ingested food) of S. litura. Beauveria brongniartii Fe0NPs induced reduction in glutathione-S-transferase activities throughout the infection period whereas activities of antioxidant enzymes decreased during later periods of infection. These findings suggest that B. brongniartii Fe0NPs can potentially be used in biorational S. litura management programs.

scholarly journals An Improved Time Integration Method Based on Galerkin Weak Form with Controllable Numerical Dissipation

2021 ◽  
Vol 11 (4) ◽  
pp. 1932
Author(s):  
Weixuan Wang ◽  
Qinyan Xing ◽  
Qinghao Yang
Keyword(s):  
High Frequency ◽  
Integration Method ◽  
Time Integration ◽  
Low Frequency ◽  
Weak Form ◽  
High Accuracy ◽  
Numerical Dissipation ◽  
Frequency Range ◽  
Time Integration Method ◽  
Numerical Damping

Based on the newly proposed generalized Galerkin weak form (GGW) method, a two-step time integration method with controllable numerical dissipation is presented. In the first sub-step, the GGW method is used, and in the second sub-step, a new parameter is introduced by using the idea of a trapezoidal integral. According to the numerical analysis, it can be concluded that this method is unconditionally stable and its numerical damping is controllable with the change in introduced parameters. Compared with the GGW method, this two-step scheme avoids the fast numerical dissipation in a low-frequency range. To highlight the performance of the proposed method, some numerical problems are presented and illustrated which show that this method possesses superior accuracy, stability and efficiency compared with conventional trapezoidal rule, the Wilson method, and the Bathe method. High accuracy in a low-frequency range and controllable numerical dissipation in a high-frequency range are both the merits of the method.

scholarly journals Band notched self complementaryultra wideband antenna for wireless applications

2018 ◽  
Vol 7 (2.8) ◽  
pp. 529 ◽  
Author(s):  
Ch Ramakrishna ◽  
G A.E.Satish Kumar ◽  
P Chandra Sekhar Reddy
Keyword(s):  
High Frequency ◽  
Return Loss ◽  
Wide Band ◽  
Ultra Wideband ◽  
Impedance Bandwidth ◽  
Relative Dielectric Permittivity ◽  
Frequency Range ◽  
Ground Structure ◽  
Wireless Applications ◽  
Patch Edge

This paper presents a band notched WLAN self complementaryultra wide band antenna for wireless applications. The proposed antenna encounters a return loss (RL) less than -10dB for entire ultra wideband frequency range except band notched frequency. This paper proposes a hexagon shape patch, edge feeding, self complementary technique and defective ground structure. The antenna has an overall dimensionof 28.3mm × 40mm × 2mm, builton  substrate FR4 with a relative dielectric permittivity 4.4. And framework is simulated finite element method with help of high frequency structured simulator HFSSv17.2.the proposed antenna achieves a impedance bandwidth of 8.6GHz,  band rejected WLAN frequency range 5.6-6.5 GHz with  vswr is less than 2.

scholarly journals A Compact Four-Port Coplanar Antenna Based on an Excitation Switching Reconfigurable Mechanism for Cognitive Radio Applications

2019 ◽  
Vol 9 (15) ◽  
pp. 3157 ◽  
Author(s):  
O ◽  
Jin ◽  
Choi
Keyword(s):  
Cognitive Radio ◽  
High Frequency ◽  
Coplanar Waveguide ◽  
Low Frequency ◽  
Loop Antenna ◽  
Ultra Wideband ◽  
Frequency Range ◽  
Uwb Antenna ◽  
High Isolation ◽  
Loop Antennas

In this paper, we propose a compact four-port coplanar antenna for cognitive radio applications. The proposed antenna consists of a coplanar waveguide (CPW)-fed ultra-wideband (UWB) antenna and three inner rectangular loop antennas. The dimensions of the proposed antenna are 42 mm × 50 mm × 0.8 mm. The UWB antenna is used for spectrum sensing and fully covers the UWB spectrum of 3.1–10.6 GHz. The three loop antennas cover the UWB frequency band partially for communication purposes. The first loop antenna for the low frequency range operates from 2.96 GHz to 5.38 GHz. The second loop antenna is in charge of the mid band from 5.31 GHz to 8.62 GHz. The third antenna operates from 8.48 GHz to 11.02 GHz, which is the high-frequency range. A high isolation level (greater than 17.3 dB) is realized among the UWB antenna and three loop antennas without applying any additional decoupling structures. The realized gains of the UWB antenna and three loop antennas are greater than 2.7 dBi and 1.38 dBi, respectively.

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