This work is devoted to the experimental study of evaporating droplets of titania-, silica-, and diamond-based nanofluids on a substrate under solar radiation. The influence of various factors, including the type of a material, concentration of nanocomponents, irradiation direction, droplet volume, and substrate material, on the droplet evaporation has been investigated. As a result, the critical concentrations of nanoparticles, at which the evaporation rate reaches a stable level, have been determined for droplets of the studied nanofluids. The regimes and stages of the droplet evaporation process have been analyzed for the cases of the subcritical and critical nanoparticle concentrations. The efficiency of droplet evaporation under solar radiation has been shown to strongly depend on radiation direction. The effects of droplet volume and substrate material on the evaporation rate have been studied. In addition to the evaporation efficiency, the morphology of the structures deposited from the droplets has been analyzed. It has been shown that these structures depend on the concentration and material of nanoparticles, as well as on the regime of droplet evaporation. The results of this study enable one to gain a deeper insight into the behavior of the droplets during evaporation under irradiation especially in the IR region and confirm the promise of application of nanofluids in the solar thermal energy systems.

The practical feasibility of a wireless relative transmission scheme based on chaotic radio pulses is demonstrated. New components necessary for the implementation of this scheme have been developed. A prototype of a transmission system in the frequency range of 200–500 MHz was created on which experiments were carried out on the transmission of binary information. The measurement results correspond to the previously obtained theoretical and computational estimates on the main properties and characteristics of a new transmission scheme that uses dynamic chaos as an information carrier.

The purpose of this paper is to analyse the statistical characteristics of a Direct Chaotic Differentially Coherent communication scheme based on chaotic radio pulses in a communication channel with additive white Gaussian noise, where the chaotic signal is given by different instantaneous distributions. Methods. To achieve this goal, numerical modelling of the noise immunity of Direct Chaotic Differentially Coherent communication is conducted and compared with the results of analytical research. Results. The regularities associated with the use of chaotic signals with various statistical distributions of instantaneous values were studied. The minimum values of energy per bit to white Gaussian noise power spectral density ratio were obtained, providing the required error probabilities. Conclusion. It is shown that the proposed system works efficiently at high values of processing gain, and as the processing gain increases, the dependence of noise immunity on the specific statistical distribution of the chaotic signal is levelled out.

The problem of construction of ultra-wideband direct chaotic communication devices in the very high frequency and ultra high frequency ranges of radio waves is considered, the features of this range with respect to the propagation of electromagnetic radiation are discussed, and performance potential is evaluated. Experimental direct chaotic transceivers with a working band of 200–450 MHz, their structure, technical implementation, and characteristics are presented. The results of laboratory and field tests of prototypes are given to demonstrate transmission ranges of up to 1.5 km, which correspond to the calculated characteristics.

Экспериментально доказана возможность практической реализации беспроводной схемы относительной передачи на основе хаотических радиоимпульсов. С этой целью создан макет схемы связи в диапазоне частот 200-500 MHz для передачи двоичной информации и проведены эксперименты с ним. Полученные результаты полностью подтверждают разработанные ранее теоретически принципы функционирования схемы и ее основные свойства. Ключевые слова: динамический хаос, сверхширокополосные сигналы, относительная передача информации, корреляционный прием.

New experimental and calculated data are presented for active thermal interface materials, in which heat is removed not only due to high thermal conductivity, but also due to the evaporation of liquids, for example, water, inside a nanoporous graphene structure. It is shown that such active thermal interfaces may be new systems of active thermal control.

The study considers various thermophysical problems, including the processes of heating new nanomaterials and nanofluids, as applied to solar thermal multigeneration (steam generation and turbine and turbineless conversion into electrical energy), as well as thermoelectric generation (solar thermoelectric generation) using new nanomaterials, including graphene and its composites. The main unsolved problems of thermohydrodynamics and heat transfer in such systems are noted.

The possibility of practical implementation of differentially coherent wireless communication scheme based on chaotic radio pulses has been experimentally proven. For this purpose a prototype of that communication scheme was created in the frequency range of 200-500 MHz for binary information transmission and experiments were carried out with it. The obtained results fully confirm the previously developed theoretical principles of scheme functioning and its main properties. Keywords: dynamic chaos, ultra-wideband signals, differentially coherent information transmission, correlation reception.

The results of the development of new educational programs in the field of nanotechnology and nanomaterials in the energy sector, which have been developed and are actively used by the National Research University “MPEI”, are presented. Modern nanomaterials and nanotechnological processes in traditional and alternative (“green”) energy require new approaches, including statistical methods for the analysis and synthesis of experimental data and design options. For this reason, without the active use of machine learning methods, it is impossible to train qualified specialists in the field of promising energy problems and their solutions. Through teaching, research, and innovation, «MPEI» exceptional community pursues its mission of service to the nation and the world.

This research examines thermal performance of metal-graphene nanocomposites for thermal management. Graphene nanoflakes and graphite microparticles were compressed with cooper meshes under different pressures. The prepared samples were characterized using optical microscopy. The fabricated samples of cooper-graphene composites were studied to determine the droplet evaporation rates and contact angles at different temperatures including film boiling.

The possibility of creation of biological eye analogue working in radio-frequency is considered in order to observe the environment using artificial radiolight. In accordance with its biological prototype, this analogue consists of system of sensitive elements (retina), lens-like focusing element and the set of directional antennas that are used for primary processing of received noise-like ultrawideband radiation. The experimental device of this type is proposed and its performance is demonstrated.

In this paper, we show the possibility of organizing multi-user access based on a relative transmission scheme using chaotic radio pulses as a data carrier. The maximal number of subscribers and information capacity of a multi-user system are theoretically estimated. The validity of the obtained theoretical results was confirmed by computer modeling.

Popularisation of the key scientific problems occupied a significant place in D. I. Trubetskov's work. In memory of this fact, the problem of electromagnetic field affecting biological objects is discussed in a popular manner in this article. This problem has more than a century in it's history, but still being far from the final solution. Objectives. Analyze the problem of the interaction of electromagnetic fields with biological objects and social structures as complex multielement systems, and assess the possibility of identifying new effects in their behavior. Methods. As a result of many studies in different countries, by the mid-60s of the twentieth century, an idea was formed about the complex and systemic nature of the influence of electromagnetic fields on biological objects. Therefore, the interaction of electromagnetic fields with biological objects and social environments is considered in the work as a problem of external influence on complex multielement interconnected systems, using conceptual approaches of nonlinear dynamics. Results. It is shown that along with the effects of EMF on individual biological objects, there are effects of the influence of the information component of EMF on social systems, the elements of which are people considering as biological objects. The threshold power flux density where the influence effects on the social systems begin to manifest is significantly lower than the one for biological objects. Conclusion. Effective approaches aimed to reduce the negative impact of microwave radiation on humans can be implemented using personal means for monitoring the level and the received dose of radiation - electromagnetic radiation dosimeters, which are actually analogous to thermometers for measuring body temperature.

The possibility of creating an analog of the biological eye in the radio range for observing the surrounding space in artificial radio light is considered. As in the biological prototype, the analog has a system of sensitive elements (retina), a lens-type focusing element and a set of directional antennas, which are used for the primary reception of noiselike ultrawideband radiation. An experimental device of the considered type is designed and the operability of the proposed technical solution is demonstrated.

In this paper, we present the measurement results of the dynamics of the level of electromagnetic microwave radiation obtained using "MERA" personal dosimeters developed at the Kotelnikov Institute of Radioengineering and Electronics, Russian Academy of Sciences. The measurements were performed under various conditions: in Russia and foreign countries, in megacities and resort areas, day and night, and in public transport and airplanes. The data obtained based on direct long-term measurements allows assessing the real electromagnetic microwave load exerted by modern means of mobile communications on the environment surrounding a person.

Application of dynamic chaos for the illumination of the surrounding space by artificial incoherent sources of microwave radiation with the purpose of its subsequent observation using special receiving equipment is considered. An incoherent broadband microwave radiation field is provided by "radio light lamps" based on dynamic chaos generators. The radio light is received with specially designed sensitive elements that combine the properties of an envelope detector in communication systems and a radiometer. It is shown that with the help of directional antennas connected to these sensitive elements, it is possible to create receivers with spatial resolution for visualizing a part of the surrounding space in artificial radio light. Radio light images of a room have been obtained. The possibility to detect changes associated with the emergence of new objects on these images is demonstrated.

A problem of an increase in the range of direct chaotic ultrawideband transceivers is considered. Parameters that determine the range are theoretically estimated. Experimental transceivers with a capacity of up to 12 Mbit/s and a range of greater than 200 m are developed and fabricated. The corresponding software is developed and tested. Experimental characteristics of the devices prove the theoretical estimations.