Search

The work attempts to build a mathematical model of energy audit as an activity associated with a complex of technical, organizational and economic events. Measures of these events are aimed to identify the possibility of cost-effective optimization of the consumption of energy resources at industrial enterprises. The goal of the energy audit is to identify sources of wasteful energy consumption and energy losses, to develop a comprehensive energy saving program, and to increase energy efficiency. The logical basis of the activity under consideration is the presentation of the cobination of energy and material flows in the enterprise, as a set of connected graphs. The number of graphs considered is determined by the many types of material and energy flows (electricity, thermal energy, enterprise products, etc). The node of the graph, depending on the details of the description, can be either an entire enterprise, which will be a set of interacting enterprises, or a workshop, or installation, etc.

Requirements to gyroscopes of strapdown inertial navigation systems for aircraft application are formulated. The construction of a ring helium – neon laser designed for autonomous navigation is described. The processes that determine the laser service life and the relation between the random error of the angular velocity measurement and the surface relief features of the cavity mirrors are analysed. The results of modelling one of the promising approaches to processing the laser gyroscope signals are presented. (laser gyroscopes)

We have detected and analysed narrow high-contrast coherent population trapping (CPT) resonances, which are induced in absorption of a weak monochromatic probe light beam by counterpropagating two-frequency pump radiation in a cell with rarefied caesium vapour. The experimental investigations have been performed by the example of nonclosed three level Λ-systems formed by spectral components of the D2 line of caesium atoms. The applied method allows one to analyse features of the CPT phenomenon directly at a given low long-lived level of the selected Λ-system even in sufficiently complicated spectra of atomic gases with large Doppler broadening. We have established that CPT resonances in transmission of the probe beam exhibit not only a higher contrast but also a much lesser width in comparison with well- known CPT resonances in transmission of the corresponding two-frequency pump radiation. The results obtained can be used in selective photophysics, photochemistry and ultra-high resolution atomic (molecular) spectroscopy.

When gravitational waves (GW) spread in space-time, we usually say that spatial distances between reference points are distorted. The LISA project was developed to measure distortion in space. Simultaneously with the GW arrival, time intervals are also distorted. For this purpose, the pulsar timing method was developed. This article proposes to use a network of stabilized atomic clocks installed on deep-space spacecraft to measure time interval. A preliminary estimate of the required accuracy of clocks when registering GW is offered. It is indicated that a network of clocks installed on LISA-type spacecraft can serve as an additional and independent GW detection channel.

The article considers modeling of modern heat exchange systems which use thermal energy for its beneficial use. The proposed mathematical model makes it possible to investigate systems with utilization of thermal energy. The article presents the results of simulation of heat exchange processes using heat energy recovery for internal combustion engines.

A method for determining the basic energy characteristics of a hybrid car engine is presented. The technique takes into account parameters of the vehicle and parameters of the driving mode during operation. The basis of the technique is traction power and energy calculation. According to the source data, the flow of energy passing through mechanical, electrical chains and through the storage of electrical energy is determined. The technique is implemented in the form of algorithms for the calculation program and allows one to simultaneously receive the main technical characteristics of the vehicle when it is equipped with a hybrid engine of a sequential, parallel and mixed type. The presented method allows one to obtain the following values: the required power of the internal combustion engine, the required power of the motor generator, the minimum capacity of the electrical energy storage device, the estimated fuel consumption. This article presents an example of calculating the basic parameters of a combined power plant for a car weighing 1500 kg when driving it along the standard European driving test cycle. Similar calculations can also be carried out for any other cycle and parameters of the vehicle, including the bus, truck, and tractor.

The paper adduces theoretical data and results of experimental studies confirming the existence of gravitational radiation predicted by the general theory of relativity. It also shows that studying of gravitational waves detection is based on equations of general relativity and equations of electrodynamics, and for modeling of gravitational waves space by sources, equations of hydrodynamics are used.

It is shown that using the state-of-the-art quantum interferometer (SQUID) with the resolution 10-6 Φ0 Hz-1/2 = 2.07 × 10-21 Wb Hz-1/2, coupled to a magnetostrictor, playing the role of tensomagnetic transducer, it is possible to construct a system for detecting pressure variations with the ultimate sensitivity of 10-13 Pa Hz-1/2 and for measuring specific elongation with the sensitivity of 10-24 Hz-1/2. The analysis of physical grounds of the inverse magnetostriction effect demonstrates concrete ways to essentially higher efficiency of tensomagnetic conversion. The estimates performed demonstrate the possibility of using the SQUID/magnetostrictor system as a detector of gravitational waves. Other possibilities of using this system for solving both fundamental and applied problems are also considered.

We investigate the strong field lensing observables for the Damour-Solodukhin wormhole and examine how small the values of the deviation parameter $\lambda $ need be for reproducing the observables for the Schwarzschild black hole. While the extremely tiny values of $\lambda$ indicated by the matter accretion or Hawking evaporation are not disputed, it turns out that $\lambda $ could actually assume values considerably higher than those tiny values and still reproduce black hole lensing signatures. The lensing observations thus provide a surprising counterexample to the intuitive expectation that all experiments ought to lead to the mimicking of black holes for the same range of values of $\lambda$., Comment: 6 pages

The possibility of reconstructing a singular wave front of laser beams by the local tilts of the wave front measured with a Hartmann sensor is considered. The accuracy of the reconstruction algorithm described by Fried is estimated and its modification is proposed, which allows one to improve the reliability of the phase reconstruction. Based on the Fried algorithm and its modification, a combined algorithm is constructed whose advantages are demonstrated in numerical experiments.

The solubility of carbonated hydroxyapatite powders and granulated carbonated hydroxyapatite produced from the synovial biofluid model solution has been studied. The kinetic characteristics of dissolution were determined. It was found that the solubility of carbonated hydroxyapatite is higher as compared to that of hydroxyapatite. The impact of the organic matrix on the rate of sample dissolution was revealed. For HA-gelatin composites, as the gelatin concentration grows, the dissolution rate becomes greater, and a sample of 6.0 g / L concentration has higher resorbability. The results of the research can be used to study the kinetics of dissolution and the biocompatibility of ceramic materials for medicine, namely for reconstructive surgery, dentistry, and development of drug delivery systems.

The scheme of a magnetic calorimeter for recording extremely low energy releases is developed. The calorimeter is activated by the method of adiabatic demagnetisation and its response to the energy release is measured with a superconducting quantum interference device (SQUID). The estimate of the ultimate sensitivity of the calorimeter with the SQUID demonstrates the possibilities of its application for detecting ultralow radiation intensity, recording single X-ray quanta in the proportional regime and other events with ultralow energy releases. The scheme of the calorimeter with the SQUID on matter waves in superfluid 4He is proposed.

The present theoretical work shows the possible essential rise of the resolution of the well tested sub-Doppler laser spectroscopy method, based on the optical pumping and transit of atoms (molecules) in a thin gas cell, by means of the definite spatial separation of pumping and probe light beams.

A theoretical investigation is carried out through the interaction of the plane running monochromatic light wave, having an arbitrary intensity, with atoms (molecules) of a rarefied gas in the plane cell (at the normal incidence of the wave). Cases of closed and open resonance transitions from the non-degenerate ground (or metastable) quantum level are considered. Possible sub-Doppler resonances are analysed in the wave absorption, caused by the transient establishment of the optical coherence on the transition, Rabi oscillations between its levels, and optical pumping during the free flights of particles between the walls of the cell. Results of the previous works on given problems are generalized, which were obtained at definite restrictions on the wave intensity and cell length. Moreover, non-trivial sub-Doppler spectral structures, resulting as a consequence of the dependence of the absorption saturation on the transit relaxation of particles, have been established and investigated. Such structures may consist of a number of peaks and dips caused by Rabi oscillations between the transition levels. The results obtained can be used in sub-Doppler spectroscopy and for the stabilization of laser frequencies in thin gas cells.

The dynamics of oscillation of a two-frequency gas laser was investigated theoretically and experimentally under radiation intensity self-stabilisation conditions. The investigation was carried out in the specific case of a helium—neon laser with a linear phase-anisotropic cavity (2S2—2P4 transition in Ne, wavelength λ = 1.15 μm). The feasibility of effective control of the spectrum of technical fluctuations of the output power by an external magnetic field, and also by detuning and a change in the cavity anisotropy, was demonstrated. A method was developed for simultaneous stabilisation of the intensity and frequency of the laser radiation.

In a nonequlibrium plasma of a gas-discharge HgBr lamp, the terminal electronic state of the HgBr(B–X) radiative transition with a peak wavelength of 502 nm remains populated for a relatively long time and is repeatedly excited to the B state in collisions with plasma electrons. This transfer of the HgBr molecules from the ground state X to the excited state B is the main mechanism of formation of the light-emitting molecules especially when the lamp is excited by double current pulses. According to our simulations, due to the electron-induced transitions between HgBr(X) and HgBr(B), the output characteristics of the DBD lamp operating in a double-pulse regime are better than those of the lamp operating in a single-pulse regime. In the considered case, the peak power is calculated to increase by a factor of about 2 and the lamp efficiency increases by about 50%.

A mathematical model of an adaptive optics system was described in the article. The model included two main components: the model of an adaptive mirror and model of beam propagation under conditions of thermal blooming. Results of numerical simulation of adaptive optics systems were compared with data of laboratory experiments. High reliability of the model was shown.

Metastable state relaxation in a gravitational field is investigated in the case of non-critical binary solutions. A relaxation description is presented in terms of the time-dependent Ginzburg-Landau formalism for a non-conserved order parameter. A new ansatz for solution of the corresponding partial nonlinear stochastic differential equation is discussed. It is proved that, for the supersaturated solution under consideration, the metastable state relaxation in a gravitational field leads to formation of solute concentration gradients due to the sedimentation of subcritical solute clusters. The pure discussion of the possible methods to compare theoretical results and experimental data related to solute sedimentation in a gravitational field is presented. It is shown that in order to describe these experiments it is necessary to deal both with the value of the solute concentration gradient and with its formation rate. The stochastic nature of the sedimentation process is shown.

A new mathematical ansatz is developed for solution of the time-dependent Ginzburg-Landau nonlinear partial differential equation describing metastable state relaxation in binary (solute+solvent) non-critical solutions with non-conserved scalar order parameter in presence of a gravitational field. It has been demonstrated analytically that in such systems metastability initiates heterogeneous solute redistribution which results in the formation of a non-equilibrium singly-periodic spatial solute structure in the new solute-rich phase. The critical radius of nucleation and the induction time in these systems are gravity-dependent. It has also been proved that metastable state relaxation in vertical columns of supersaturated non-critical binary solutions leads to formation of the solute concentration gradient. Analytical expression for this concentration gradient is found and analysed. It is concluded that gravity can initiate phase separation (nucleation or spinodal decomposition).

Carbonated-hydroxyapatite (CHA) and Si-hydroxyapatite (Si-HA) precipitation have been synthesized from the model bioliquid solutions (synovial fluid and SBF). It is found that all the samples synthesized from the model solutions are single-phase and represent hydroxyapatite. The crystallization of the modified hydroxyapatite on alloys of different composition, roughness and subjected to different treatment techniques was investigated. Irradiation of the titanium substrates with the deposited biomimetic coating can facilitate further growth of the crystal and regeneration of the surface.

A quasi-quantum-mechanical percolation model, which imitates the process of oil displacement by water from the oil reservoir, is suggested. The Hamiltonian describing the irreversible evolution process of the percolation lattice, which models the oil reservoir, is constructed. With the help of the computer calculations for the rectangular plane lattice, the time development of the process under consideration is observed. The authors consider the critical behaviour within the time interval t1

In this paper, we wish to investigate certain observable effects in the recently obtained wormhole solution of the Eddington-inspired Born–Infeld (EiBI) theory, which generalizes the zero-mass Ellis–Bronnikov wormhole of general relativity. The solutions of EiBI theory contain an extra parameter κ having the inverse dimension of the cosmological constant Λ, and which is expected to modify various general relativistic observables such as the masses of wormhole mouths, tidal forces and light deflection. A remarkable result is that a non-zero κ could prevent the tidal forces in the geodesic orthonormal frame from becoming arbitrarily large near a small throat radius (${r}_{0}\sim 0$) contrary to what happens near a small Schwarzschild horizon radius ($M\sim 0$). The role of κ in the flare-out and energy conditions is also analyzed, which reveals that the energy conditions are violated. We show that the exotic matter in the EiBI wormhole cannot be interpreted as a phantom ($\omega =\frac{{p}_{{\rm{r}}}}{\rho }\lt -1$) or ghost field ϕ of general relativity due to the fact that both ρ and p (r) are negative for all κ.

In this paper detection of vortex beam parameters in a turbulent atmosphere is considered numerically. The characteristics of singular radiation were obtained with the use of wavefront gradients, i.e. an ideal system was simulated. After that, a model of a Shack–Hartmann sensor was included in the calculation schematic which allowed us to assess the influence of the device limitations on the precision of registration and optimize its parameters.