Radiative charge exchange in ion–atom collisions at intermediate impact velocities: spectral characteristics and possibilities of experimental studies

The presence in operation of many prototypes of UAVs with propeller propellers, the use of such devices at relatively low altitudes and flight speeds makes the problem of noise reduction from UAVs urgent both from the point of view of acoustic imperceptibility and ecology.The aim of the work is to determine a set of methods that help to reduce the visibility of UAVs in the acoustic range. It is shown that the main source of noise from the UAV on the ground is the power plant, which includes the engine and the propeller. The parameters of the power plants influencing the processes that determine the acoustic signature of the UAV were investigated. A comprehensive analysis of the factors affecting visibility was carried out. The power plants include two-stroke and four-stroke engines, internal combustion and two-blade propellers. The use of silencers on the exhaust of the internal combustion engine was considered. The spectral characteristics of the acoustic fields of the propeller-driven power plants for the operating sample of the UAV "Eco" were obtained. The measurements were carried out in one-third octave and 1/48 octave frequency bands under static conditions. The venue is the KhAI airfield. Note that the propellers that were part of the power plants operated at Reynolds numbers (Re0,75<2*105), which can significantly affect its aerodynamic and acoustic characteristics. It is shown that when choosing a UAV control system, one should take into account the fact that two-stroke piston engines are the dominant source in the noise of propeller-driven control systems in the absence of a hood and mufflers in the intake and exhaust tracts. The use of a four-stroke internal combustion engine significantly reduces the noise of the control system. In the general case, the position of the boundaries of the zone of acoustic visibility of a UAV at the location of the observer is determined by the ratio between the intensity of acoustic radiation perceived by the observer from the UAV and the intensity of sound corresponding to the natural acoustic background and depends on the degree of manifestation of acoustic effects accompanying the propagation of sound in a turbulent atmosphere - the refraction of sound waves. Absorption and dissipation of acoustic energy. The calculation and comparison of the UAV detection range was carried out taking into account the existing natural maskers.The results of experimental studies are presented that allow assessing the degree of acoustic signature of the UAV. A set of measures aimed at reducing the intensity of the acoustic signature of the UAV in various regions of the radiation spectrum has been determined.

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Diagnostics of Advanced Power Intensive Power Sources Based on the Acoustic Spectroscopy Method

Herald of the Bauman Moscow State Technical University Series Natural Sciences ◽

10.18698/1812-3368-2021-6-121-127 ◽

2021 ◽

pp. 121-127

Author(s):

E.M. Petrenko ◽

V.A. Semenova

Keyword(s):

High Reliability ◽

Methodological Approach ◽

Spectral Characteristics ◽

Experimental Studies ◽

Mechanical Action ◽

Mean Value ◽

Spectroscopy Method ◽

Power Sources ◽

Acoustic Spectroscopy ◽

Noise Diagnostics

Objective of this article is to develop a method for lithium chemical current sources diagnostics, which would ensure high reliability in assessing their technical state (primarily, the discharge degree) close to potentially achievable introduction of the acoustic spectroscopy method. Today, microcalorimetric studies and methods of impedance and noise spectroscopy make it possible to predict the lithium chemical current sources service life. However, implementation of the microcalorimetric studies result requires a lot of time accompanied by using stationary and large-size equipment, which is practically impossible in the autonomous conditions. Application of the impedance spectroscopy method provides satisfactory results only with high degrees of discharge. In the range of 0--30 %, it is very difficult to determine the discharge degree, since noticeable alteration in the correlate within its deviation from the mean value is missing. In this regard, it is proposed in order to provide diagnostics of the lithium chemical current sources in the region of initial degrees of discharge to introduce the noise diagnostics method. In order to increase reliability of the diagnostic estimates, it is advisable to use acoustic spectroscopy as a physically independent method in diagnosing the state of lithium chemical current sources. Results of the preliminary measurements analysis confirm the prospects of using the acoustic spectroscopy method in assessing the current state of primary lithium chemical current sources. Experimental studies of the lithium chemical current sources response to acoustic (mechanical) action made it possible to determine a set of parameters characterizing the proposed methodological approach. This provided a possibility to search for correlation dependences of the lithium chemical current sources spectral characteristics on the degree of their discharge. This makes it possible to use the method of acoustic spectroscopy in prompt and reliable diagnostics of the primary current sources in the region of low discharge degrees

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Experimental Approaches to Neutrino Nuclear Responses for ββ Decays and Astro-Neutrinos

Frontiers in Physics ◽

10.3389/fphy.2021.650421 ◽

2021 ◽

Vol 9 ◽

Author(s):

Hiroyasu Ejiri

Keyword(s):

Matrix Element ◽

Charge Exchange ◽

Nuclear Matrix ◽

Experimental Studies ◽

Nuclear Matrix Element ◽

Exchange Reactions ◽

Fundamental Properties ◽

Experimental Approaches ◽

Nuclear Responses ◽

Beta Decays

Fundamental properties of neutrinos are investigated by studying double beta decays (ββ-decays), while atro-neutrino nucleo-syntheses and astro-neutrino productions are investigated by studying inverse beta decays (inverse β-decays) induced by astro-neutrinos. Neutrino nuclear responses for these ββ and β-decays are crucial for these neutrino studies in nuclei. This reports briefly perspectives on experimental studies of neutrino nuclear responses (square of nuclear matrix element) for ββ-decays and astro-neutrinos by using nuclear and leptonic (muon) charge-exchange reactions

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Experimental studies on output, spatial, and spectral characteristics of a microdroplet dye laser containing Intralipid as a highly scattering medium

IEEE Journal of Quantum Electronics ◽

10.1109/3.541672 ◽

1996 ◽

Vol 32 (11) ◽

pp. 1864-1873 ◽

Cited By ~ 23

Author(s):

H. Taniguchi ◽

S. Tanosaki ◽

K. Tsujita ◽

H. Inaba

Keyword(s):

Spectral Characteristics ◽

Experimental Studies ◽

Dye Laser ◽

Scattering Medium ◽

Highly Scattering Medium

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Autodyne Sensor Signals with Amplitude-Frequency Modulation of Radiation

Sensors ◽

10.3390/s20247077 ◽

2020 ◽

Vol 20 (24) ◽

pp. 7077

Author(s):

Vladislav Noskov ◽

Rinat Galeev ◽

Evgeniy Bogatyrev ◽

Kirill Ignatkov ◽

Kirill Shaidurov

Keyword(s):

Mathematical Model ◽

Frequency Modulation ◽

Spectral Characteristics ◽

Experimental Studies ◽

Harmonic Amplitude ◽

Feedback Parameter ◽

Planar Diode ◽

Sensor Signals ◽

Amplitude And Frequency Modulation ◽

Selection Of

A mathematical model of an autodyne oscillator with a combined amplitude-frequency modulation, which is under the influence of its own radiation reflected from the target, is developed. The main relations are obtained for analyzing the autodyne response of a single-circuit oscillator depending on the delay time of the radiation reflected from the target with an arbitrary law of simultaneous amplitude and frequency modulation. The characteristics of the amplitude selection of signals, as well as their temporal and spectral characteristics, are calculated for harmonic amplitude-frequency modulation. The features of signal formation are established for various values of the amplitude and frequency modulation parameters and the feedback parameter of the “oscillator—target” autoparametric system. The results of experimental studies, performed on a Tigel-0.8M hybrid-integrated Ka-band oscillator module with a Gann mesa-planar diode, confirmed the findings of the theoretical analysis.

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Experimental Studies on the Role of Vitamin a in the Inner Ear

Otolaryngology ◽

10.1177/01945998780860s411 ◽

1978 ◽

Vol 86 (4_suppl) ◽

pp. ORL-595-ORL-620 ◽

Cited By ~ 3

Author(s):

Richard A. Chole

Keyword(s):

Vitamin A ◽

Guinea Pig ◽

Inner Ear ◽

Spectral Characteristics ◽

Experimental Studies ◽

Normal Function ◽

Fluorescent Compound ◽

Guinea Pig Cochlea ◽

Vitamin A Acid

With the sole exception of the hair cells of the inner ear, where information is lacking, all special somatic afferent receptor cells have been shown to be dependent upon vitamin A for normal function. In view of the paucity of information on the role of vitamin A in the inner ear, three experiments were performed to examine this relationship. Temporal bone histopathology was studied in rats deprived of vitamin A. In a second experiment, vitamin A-deficient rats were maintained with vitamin A acid and the histopathology was studied under the light microscope. In the third experiment, a microfluorometric estimate of the content of vitamin A in the guinea pig cochlea was performed. A fluorescent compound with the exact spectral characteristics of vitamin A was found in the guinea pig cochlea at a concentration of 21.2μg/gm, which is ten times the vitamin A concentration found in most other tissues.

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RESEARCH ON THE EFFECT OF ELECTROMAGNETIC FIELD OF EHF BAND ON SEEDS OF CULTURAL PLANTS

Podilian Bulletin: Agriculture, Engineering, Economics ◽

10.37406/2706-9052-2020-1-15 ◽

2020 ◽

pp. 124-131

Author(s):

O.A. Olenyuk ◽

O.V. Tkach

Keyword(s):

Seed Treatment ◽

Power Flow ◽

Spectral Characteristics ◽

Experimental Studies ◽

Cultivated Plants ◽

Flow Density ◽

Production Technologies ◽

Technological Processing ◽

Plant Yields ◽

Sowing Seed

In modern conditions, to increase the yield of cultivated plants use pre-sowing seeds with the use of chemical and biological products. Due to the orientation of the world's leading countries on environmentally friendly agricultural production technologies, more and more attention is being paid to the development of electro-technological processing methods. The main advantage of electromagnetic technology for pre-sowing seed treatment with low-energy radiation of the EHF range is the possibility of improving their growth and development by mobilizing the internal reserves of the seed itself, accelerating the diffusion of molecules through the cell membrane, the speed of chemical reactions and causing redness plants and promotes yield without chemical or biological agents or genetic engineering methods. The technology of seed treatment EMF EHF allows to store in the seed all the nutrients, vitamins and minerals, which when processed by other methods is difficult to achieve. The study is based on the analysis of literature, theoretical and experimental studies of the energy and spectral characteristics of the diode generator in the EHF wavelength range, which can be concluded that the increase in plant yields is possible based on the use of millimeter-wave electromagnetic radiation for pre-sowing seed treatment. The article proposes a technique for investigating the energy characteristics of a semiconductor six-diode generator on avalanche-spanning diodes for pre-sowing seed treatment of cultivated plants. The result of the developed technique is that one of the main elements of the plant for pre-sowing seed treatment is the emitter of EM energy, which should form the necessary radiation pattern and provide a sufficient level of power flow density on the grain.

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АКУСТИЧНА ПОМІТНІСТЬ БЕЗПІЛОТНИХ ЛІТАЛЬНИХ АПАРАТІВ З СИЛОВОЮ УСТАНОВКОЮ, ЩО МІСТИТЬ ЕЛЕКТРОДВИГУН І ПОВІТРЯНИЙ ГВИНТ

Open Information and Computer Integrated Technologies ◽

10.32620/oikit.2020.88.06 ◽

2020 ◽

pp. 81-94

Author(s):

В. В. Руденко ◽

В. П. Чернолихова

Keyword(s):

Power Plant ◽

Electric Motor ◽

Acoustic Radiation ◽

Spectral Characteristics ◽

Experimental Studies ◽

Noise Spectrum ◽

Acoustic Characteristics ◽

Acoustic Signature ◽

Constant Pitch ◽

Static Conditions

The presence in operation of many prototypes of UAVs with propeller propellers, the use of such devices at relatively low altitudes and flight speeds makes the problem of reducing the noise generated during UAV flights urgent both from the point of view of acoustic visibility and ecology.The main source of the UAV's acoustic signature is its power plant, which includes the engine and propeller.The tasks of this work, the solution of which requires the implementation of experimental studies, include the determination of the power, spatial and spectral characteristics of the acoustic fields of propeller driven power plants of UAVs with an electric drive. The propeller is one of the main sources of acoustic radiation produced by the power plant. The influence on the acoustic characteristics of the power plant was investigated: changes in the diameter of the propellers with a constant pitch, changes in the number of blades and the number of revolutions (peripheral speeds of the propeller). The possibility of reducing the noise produced by the propeller by changing the nature of the noise spectrum was considered. The rotor rotation noise, especially of its five first harmonics, is one of the most noticeable parts in the noise spectrum of a propeller engine installation. Therefore, a hypothesis was considered and put into practice to reduce the acoustic signature of UAVs by reducing the noise of these components due to their shift to the region of higher frequencies, at which sound vibrations in the air decay faster. A comparison technique is proposed. The measurements were carried out under static conditions, in the KhAI anechoic chamber. Note that the propellers involved in the experiments operated at Reynolds numbers (Re0.75 <1*105), which can significantly affect its aerodynamic and acoustic characteristics. An empirical formula was obtained for the 11 × 6" «Aero-naut» propeller, which makes it possible to estimate the noise produced by this propeller when designing for a given flight mode in a given direction. The possibility was considered in the future to have a database of frequently used propellers. The contribution of harmonic noise components was considered propeller in the direction of its radiation. The contribution of the brushless electric motor to the intensity of acoustic radiation of the UAV power plant is determined. It is noted that the main contribution to the noise of a power plant with a brushless electric motor is made by the propeller. At the same time, the noise of a brushless electric motor can significantly increase in the range of 2 ... 3 kHz with wear of rolling bearings.

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Experimental studies on simulated circumstellar grains

Symposium - International Astronomical Union ◽

10.1017/s0074180900157365 ◽

1987 ◽

Vol 122 ◽

pp. 559-560

Author(s):

Joseph A. Nuth ◽

Bertram Donn

Keyword(s):

Spectral Characteristics ◽

Experimental Studies ◽

Nucleation Process ◽

Grain Formation ◽

Shed Light

Over the last few years a better understanding of the chemistry inherent in the refractory nucleation process has emerged from experimental studies performed in several laboratories. These studies shed light not only upon the factors which might control the onset of grain formation, but also on the spectral characteristics of freshly condensed grains.

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