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The concept and a new method for the shielded development of bottom gas hydrates have been proposed, the technological phases and constructive elements of their implementation have been substantiated. The research provides for the realization of the idea suggesting the simultaneous dissociation of the vast areas of a gas hydrate deposit, management of the targeted process of the penetration of methane recovered from gas hydrates into water space and its accumulation under the extensive gas-collecting shield wherefrom it is removed by bottom pipe transportation facilities. To do hydraulic fracturing, a well is drilled into the plane of the junction of the surface of a gas hydrate deposit and the rocks of a roof, the open system of fissures in the rocks of a roof is made through which produced gas is released to a gas-collecting blanket in a water.

In this paper, the functional features of IoT services, as well as the criteria for their evaluation and selection were investigated. Existing international standards of cloud services quality for IoT systems have been analysed. A recommendation technique has been developed for selecting an IoT service for storing, processing and visualizing data from the Smart House system. Practical examples of IoT services and cloud platforms usage for the remote laboratory Smart House & IoT are shown.

Abstract The energy efficiency is one of the most important issues nowadays; the problem with the buildings heating is especially relevant for Ukraine. The aim of the paper is to develop a convenient tool building energy performance analysis based on regression model for internal air temperature prediction, depending on a number of internal and external influential factors. The external climatic factors, such as outside air temperature, wind speed and direction, solar heat gains depending on building fenestration surfaces orientation, are considered. Internal factors include heating load, number of floors, air exchange rate etc. In order to achieve the goal, a room dynamic simulation model is created in the EnergyPlus software. A number of simulations are carried out based on the created building energy model . The individual and aggregate selected factors influence on inside air temperature change is considered. The general structure of the multivariate nonlinear regression model for inside air temperature determination is analyzed and selected. Constant coefficients are obtained for each selected influencing factor, and verification of the received nonlinear regression model is performed based on simulation data using January climatic data from the IWEC file. The adequacy of the obtained regression model is estimated by the corrected determination coefficient (R 2 = 0.981) and Fisher's criterion (F = 1324.3), which indicates the high accuracy of the obtained multivariate nonlinear regression. The proposed approach for regression model creation can be used for other architectural and thermal properties of building envelope.

The prospects and novelty of using the expression of Lame's superellipse for approximating the curvature of shells in superplastic forming (SPF) and for predicting the geometry of a product are shown. Different versions of the SPF facilitate the realization of different radii of curvature of the shell contours, which differ significantly from the radius of the spherical segment. The regularities of the change in the radius of conjugation of the bottom and the wall of the spherical shell for various SPF variants are established.

A classification of the gas-distribution grids used in fluidized-bed apparatuses is presented along with a survey of these types of grids. Designs of grids that differ in terms of form, rigidity, and degree of mobility as well as of grids that are able to vary the cross-section of channels that enable passage of gas as well as maintain a required temperature are considered.

Abstract The development of modern power electronics (electronic modules based on metal–oxide semiconductor field-effect transistors, and insulated gate bipolar transistors, inverter modules, thyristor converters, transmitting modules of active phased array antennas, central processing units of computer equipment, etc.) is accompanied by a constant increase in the level of integration and the corresponding steady increase in the generated heat fluxes per unit volume of electronic components. It is promising to use heat pipes and thermosyphons as heat removal devices, since their equivalent thermal conductivity exceeds that of metals by orders of magnitude. The paper presents the results of an experimental study on the thermal resistance of a vertical aluminum heat pipe with isobutane, an environmental-friendly working fluid, in the heat removal conditions corresponding to the free convection of air. It is shown that the thermal resistance of the aluminum gravitational heat pipe with a threaded capillary structure is substantially lower than the thermal resistance of the aluminum thermosyphon of the same size which has a smooth surface of the body in the evaporation zone.

The thermal fields of cylindrical piezoceramic electroacoustic transducers compensated designs sealed with metal-polymer layers are considered. The analysis on a basis of analytical calculations method and the finite element method was performed. The method of cylindrical piezoceramic electroacoustic transducers compensated construction thermal fields calculation based on the solution of the Fourier thermal conductivity differential equation is developed. The technique takes into account the features of the design implementation of transducers sealing by metal-polymer layers. A system of five infinite layers, each of which models a specific structural element of the transducer was taken as a calculation model. The solution of thermal conductivity equation which allows determine the temperatures at different points of the transducer layers is found. The investigation of cylindrical type transducer models with additional structural elements and without them using the finite element method in the SolidWorks program is carried out. Numerical calculations and comparison of thermal fields obtained by these two methods are performed. As a result of the analysis it is established that there is a significant temperature difference in the polymer membranes of the transducer construction which can lead to their destruction. The obtained results can be used during the cylindrical piezoceramic electroacoustic transducers designing.

The efficiency of solar thermal collectors strongly depends on the optical properties of solar selective materials used in their design since the solar absorber surfaces should have high solar absorptance in the wavelength range of 0.3–2.5 µm and low thermal emittance in the infrared region (beyond 2.5 µm). Different design principles are developed for achieving of spectral selectivity. They are creation of intrinsic selective absorbers, multilayer absorbers, absorbers based on quantum size effect or on textured surfaces, absorber-reflector tandems (semiconductor-metal tandem or composite coatings), heat mirrors [1]. Different techniques were used for the obtaining of selective solar absorber surfaces such as sputtering, evaporation, electroplating, or they can be sprayed or spread as a paint [1]. Among the above mentioned designs of selective surfaces the composite coatings (also called cermets) attract significant attention due to their strong absorption in the solar spectrum range and transparency in the infrared. Usually, the cermet coatings consist of nanoscale metal particles embedded in a dielectric matrix, generally SiO 2 , Al 2 O 3 , and MgO, deposited on a highly infrared reflecting metal substrate like bulk Cu and Al plates or coated by Al or Cu thin films glass substrates. Particles of metals with high melting points such as Cu, Au, Ni, Mo, Cr, Co, etc. are commonly used as filler materials with dielectric matrixes. The absorbing cermet layer may have either uniform or graded metal content. An antireflective coating can be deposited on the top of cermet stack with the aim to reduce the refractive index mismatch between air and the absorbing layer. Intrinsic high resistive zinc oxide ZnO can be used as alternative to above mentioned conventional ceramic matrix materials [2]. ZnO has attracted increasing interest due to its unique ability to form a variety of nanostructures, especially in the form of vertically arranged one-dimensional (1D) nanorod arrays. The various methods have been developed for production of the well-ordered 1D ZnO nanostructures which are suitable for applications in various devices such as short-wavelength lasers, sensors, photocatalytic systems and for solar cells of third generation [2]. In comparison with high vacuum technologies pulse electrochemical deposition has high potential due to a more efficient material consumption and low investment costs. It is possible to control the preferred orientation of ZnO films and their morphology by changing such pulse parameters like the cathodic average current density or cathode on/off potentials, the pulse length, the pulse shape and the pulse period.

Real-time computer simulation is required in a number of applications, where the simulated dynamic systems are directly coupled with systems in the real world or with other systems also running in real-time. Typical problems of real-time simulations are that the dynamics of the modeled system are not represented in enough detail, either by not sampling the inputs or not producing output values frequently enough or both. Increasing the sampling frequencies may lead, as an additional problem, to real-time violations caused by insufficient computing power. The latter problem is amplified if the real-time is accelerated to achieve a kind of fast motion and reduce experiment times. In this paper, we show how the first problem can be solved by automatic frequency adjustment, minimizing the number of computations and how the remaining second problem can be reduced by trading a graceful degradation of accuracy against the computing power requirements automatically. Experiments show that simulation times could be reduced by a factor of 100 without unacceptable simulation errors.