The current state of poultry farming requires the development and application of modern technologies for daily young fledge. Young fledge of high quality guarantees the maximum profit of the production in case of its further growth. It is known that to obtain a healthy, high-immunity young fledge it is necessary to implement an effective process of the eggshell surface disinfection. Therefore, the search and development of highly efficient hatching egg disinfection technologies is an urgent task.
The article investigated the optical-frequency gas flow meter based on a transistor structure with negative differential resistance (NDR). A schematic diagram and design of an optical-frequency gas flow transducer that operates in the microwave range (0.85 to 1.5 GHz), which consists of a bipolar and field-effect transistor with a Schottky barrier, is proposed as a photosensitive element using a photoresistor. A mathematical model of an optical-frequency gas flow meter based on a transistor structure with negative differential resistance has been developed, which allows one to obtain the main characteristics of the transducer in a wide frequency range. Theoretically and experimentally, the possibility of controlling both the reactive component and the negative differential resistance from changes in control voltage and power is shown, it extends the functionality of optical transducers and allows linearization of the conversion function within (0.1 - 0.2)%. Experimental studies have shown that the greatest sensitivity and linearity of the conversion function of an opticalfrequency gas flow transducer lies in the range from 3 V to 3.5 V. The sensitivity of the developed optical-frequency gas flow transducer based on a transistor structure with NDR is 146 kHz/liter/hour, and the measurement error is ± 1.5%.
In the article, to protect the garden from insect pests, theoretical studies have been carried out on the distribution of the electrical tension of video pulses inside insects. As the source of electromagnetic impulses, the electric current density is chosen, localized in the environment surrounding the biological object. For a given source of electromagnetic impulses, it is required to determine the electromagnetic field both within the biological object and in the outer space. These fields must satisfy the system of Maxwell's equations. To convert the non-stationary problem to the problem in the frequency domain, the desired electromagnetic fields inside and outside the biological object are represented as Fourier series. As a result of the transformations, the initial non-stationary problem of the interaction of a sequence of electromagnetic impulses with a biological object is reduced to the problem of diffraction of a harmonic electromagnetic field by a dielectric cylindrical scattered simulating a biological object. A direct solution of this problem is possible only by numerical methods. To simplify the problem, an explicit formula was obtained for the field averaged over the volume occupied by the biological object by the method of integral equations. The basis of integral equations is the representation of the electromagnetic field through vector potential functions and integral formulas of the theory of vector fields. As a result of the transformations, integral equations were obtained for the electric field strength inside and outside the biological object. The obtained expressions make it possible to determine the biotropic parameters of an impulse electromagnetic field for the destruction of insect pests in orchards. Creation on this basis of more effective mobile electrophysical installations allows to keep ecologically pure fruits and berries.
This paper proposes a simple mathematical model of heating process of the human skin and adjacent inner layers with the LED radiation used in the prevention and treatment devices for various diseases. The problem takes into account the heat removal by blood flow to the vessels. It is shown that abnormal blood flow due to the compression of tissue can lead to severe heating of the body and its burn. This may result even from using small LEDs of 2,5-30 mW.
Remote photoplethysmography (PPG) imaging is an optical technique to remotely assess the local coetaneous microcirculation. In this paper, we present a model and supporting experiments confirming the contribution of skin inhomogeneity to the morphology of PPG waveforms. The physical-mathematical model of distribution of optical radiation in biological tissues was developed. It allows determining the change of intensity of optical radiation depending on such parameters as installation angle of the sensor, biological tissue thickness and the wavelength. We obtained graphics which represent changes of the optical radiation intensity that is registered by photodetector depending on installation angle of the sensor, biological tissue thickness and the extinction coefficient.