Determining the Electromagnetic Field Parameters to Kill Flies at Livestock Facilities

We have considered the electromagnetic method to kill the larvae of flies ‒ agricultural pests. To address the task, a problem on the distribution of electromagnetic fields in their body was solved. The solution is based on the Maxwell's equations in the integral form, which automatically take into consideration the boundary conditions at the surface of the larvae. Since we propose the electromagnetic radiation whose wavelength is much larger than the linear sizes of insects, the derived integral equations were solved in the approximation of quasi-statics. That made it possible to convert them into a system of inhomogeneous linear algebraic equations whose solution is the components of electric field inside the larvae of flies. The study was conducted for the single-layer and two-layer insects of an ellipsoidal shape. The obtained fields provide a possibility to determine the magnitudes of potentials that occur at the larva cover, as well as to find out which of these values lead to breaking this cover with the ensuing death of the fly larva.To construct a dependence that would relate the number of imago from the larvae of flies to the parameters of electromagnetic radiation in the presence of an additive disturbance of a random character, we employed a full-factorial second-order planning. Electromagnetic radiation was applied to the fly larvae at the end of the second age. The exposure of fly larvae to the electromagnetic radiation was carried out in a frequency range of 10.2–9.8 GHz, a power flux density of 0.62‒038 mW/cm2 and an exposure of 2‒12 s. The development of larvae was observed until the formation and release of an adult insect.Based on a multifactor experiment, we derived the optimal values for the frequencies of radiation, power flux density, and exposure. To suppress insects at livestock facilities, starting from the larval stage and up until the release of imago, the electromagnetic radiation is needed with the following parameters: frequency is 10.2 GHz; power flux density is 0.37 mW/cm2; relative instability of the generator frequency is 10-8, exposure is 6 s. The release of imago from the pupae of fly larvae at livestock premises, irradiated with electromagnetic radiation, was less than 5 %.The experiment with piglets showed that when the chemical method for treating the premises was applied, a gain in the live weight amounted to 7.2 %; when the electromagnetic method was used, it was 9.2 %. A smaller increase in the live weight upon chemical treatment is due to the fact that a chemical solution exerts a negative impact not only on flies and their larvae, but also on animals. The study that we conducted could be used to create industrial installations to kill the larvae of flies at livestock facilities

Synthesis of Radiometric Receivers on the Criterion of Statistical Invariance to Fluctuations of Strengthening and Narrow-band Interference

The tasks of practical veterinary medicine related to the development of new methods and tools for the operative diagnosis of inflammatory diseases and traumas of agricultural and domestic animals require the development of fundamentally new methods and equipment for noninvasive diagnosis of the condition of animals.For remote measurement of their own thermal electromagnetic radiation of animals, the radiometric receiver was synthesized behind the criterion of statistical invariance to the AC fluctuations and to the effect of narrow-band interference.The scheme of a synthesized radio receiver is substantiated, which is invariant with respect to the AC fluctuations and completely invariant with respect to a narrow-band harmonic type. The peculiarity of this scheme is that in this radio receiver the input signal coming from the antenna in the input circuit is divided by power into two components, one of which is delayed by the time τ, and then these components are added together in the adder. Then there is amplification followed by division into two components, one of which is delayed for the same time τ, and then these components are multiplied, and their product is averaged.In accordance with the obtained expressions, for the impulse response of the input circuit and the quadratic detection scheme, the structure of the synthesized radio measuring receiver is constructed. For practical purposes, a radio measuring receiver with parameters is made: sensitivity – 10-17 W; frequency range – 30–40 GHz; measuring speed – 0.5 s; measurement accuracy – 0.1–0.2 ºC.Practical testing of the radiometric receiver shows the possibility of displaying the temperature of internal tissues, obtaining a visual picture of the heat field, which allows the veterinarian to establish the correct diagnosis

Theoretical Analysis of the Adaptive System for Suppression of the Interference Concentrated on a Spectrum

The object of research is the process of interference suppression in a passive radiometric receiver, centered over the interference spectrum, with a random or varying frequency. Noise immunity can be increased by means of special circuits preventing the receiver from overloading and using differences in the characteristics of useful signals and interference to suppress the latter. As a rule, the frequency of noise oscillation is never accurately known and, in addition, the actual interference is never purely harmonic. Therefore, it became necessary to theoretically consider the degree of interference suppression by the input circuit of the radiometer at an unknown value of the interference frequency and the finite width of the spectrum, and also theoretically substantiate possible ways of constructing adaptive devices for suppressing real narrow-band noise.An expression is obtained for the suppression coefficient of the interference concentrated on a spectrum, which shows that the interference will be suppressed automatically for the optimal choice of the parameters ka, τ, T of the servo system.In the paper, a functional diagram of a radiometric receiver is presented, which uses an adaptive system to suppress the spectrum-centered interference. The adaptive system is based on the inclusion in the radiometric receiver circuit of additional compensating circuit interference. The interference compensating circuit makes it possible to increase the sensitivity of the receiver to 10-20 W with an accuracy of 0.1 ºC and a response rate of 2...4 s. In addition to interference suppression, the compensating link after the intermediate frequency amplifier is provided with interference suppression and an input circuit. In this case, the overall amplification in the noise immunity of the radiometric receiver in comparison with the compensating receiver, as calculations for typical characteristics show, will not be worse than 30 dB

Analysis of the Electromagnetic Field of Multilayered Biological Objects for Their Irradiation in a Waveguide System

We report theoretical study on the distribution of electromagnetic field in biological objects. To perform the analysis, we selected multilayer bio-objects the size less than a wavelength of the irradiating field. In order to investigate diffraction of electromagnetic wave on the biological objects of a given type, we used integral Maxwell equations in combination with boundary conditions both at the border of the object's layers and at the border of a guiding electrodynamic structure.A theoretical research into creation of a waveguide system was conducted for the irradiation of biological objects with dimensions less than a wavelength of the irradiating field. The waveguide system employed two diffusers: a biological object and a metallic sphere. Location of the bio-object was permanent while the sphere could move along a section of the waveguide. The result of research is the obtained dependence of reflectance coefficient on the distance between diffusers. Reflectance coefficient was obtained for frequency 58.6 GHz, waveguide dimensions d=10.668 mm, h=4.318 mm, radius of the metallic sphere 4 mm, dielectric permittivity of biological objects from 2 to 14 units the size Calculations showed that by selecting the distance between a bio-object and a metallic sphere, it is possible to achieve that the bio-object is located in the antinode of the electromagnetic fiel