THE TECHNOLOGY OF WINTER CONCRETING OF MONOLITHIC FRAME STRUCTURES WITH SUBSTANTIATION OF HEAT TREATMENT MODES BY SOLUTIONS OF THE DIFFERENTIAL EQUATION OF THERMAL CONDUCTIVITY OBTAINED BY THE METHOD OF GROUP ANALYSIS

An innovative method for calculating thermal fields inside monolithic structures has been developed, based on the use and analysis of nonlinear differential equations. The innovativeness of the method lies in the approach to the analysis of nonlinear physical processes using nonlinear differential equations. Thanks to the method of group analysis, 13 expressions are obtained from complex mathematical equations, which are easy to use and depend on several empirical coefficients. It is assumed that this calculation method is a priori more accurate than the existing ones, as well as available to people at a construction site without higher mathematical education, which makes it a priority for research. The applicability of this method must be proven by linking empirical coefficients and variables to the conditions of the experiments, while obtaining reliable data that will turn out to be more accurate than the existing calculation methods. This article demonstrates a systematic approach to establishing the suitability of using the method of group analysis of differential equations for problems of winter concreting on the basis of laboratory experiments under stationary conditions. The equations were subject to verification, which, according to the physical description, correspond to the real conditions of the course of thermal processes inside monolithic structures. Based on the obtained processing results, it was decided that it was necessary to further study the innovative method in the conditions of the construction site, but only for some expressions that showed the best results at the stage of laboratory tests.

Investigation of tape flexures for space borne deployable structures

Space exploration arises the demand for launching large size structures to satisfy the need of high bandwidth telecommunication, earth observation and deep space interplanetary missions. Launching of these monolithic structures of sizes 3 m or more are not feasible due to limited launch fairing space of state-of-the-art launch vehicles. Therefore, the development of innovative deployment mechanisms is need of the hour. Deployment process of space borne deployable systems is the process of transition from mechanism to structure which is one of the unreliable stage due to existence of many conventional rotary joints which causes loss of energy due to backlash, friction and misalignment. An investigation study is presented in this paper for churning out a solution of flexible hinges using tape springs in state-of-the-art space deployable configurations which eliminates the factors causing loss of energy. Analytical and experimental methods are evaluated for investigating the bending behaviour of tape flexures. Tape flexures demonstrate to be a suitable candidate for compliant deployable configuration. The proposed configuration with combination of two tape flexures mounted in such a way that concave curve of each tape faces each other are structurally analysed for desired rotation angle. A comparison study is carried out for various material options of single and double layered tape flexures proposed for a flexure hinge. Practical feasibility of the proposed configuration is also demonstrated successfully on space borne deployable structures.

Numerical modelling of heat treatment of concrete of monolithic structures of buildings in winter conditions of construction

The paper presents the results of numerical modeling of heat treatment of concrete of a monolithic floor using a heating wire in winter conditions, depending on factors such as ambient temperature, wind speed, isothermal curing temperature, and others. The following parameters were taken as the main parameters for calculating the heat treatment of concrete: the geometric dimensions of the concreting area, the type and dimensions of the thermal insulation layer to ensure thermal protection of the monolithic structure during the heat treatment of concrete, the type and characteristics of transformers that provide the necessary power for preheating and heating concrete of monolithic floors, as well as the class of concrete, cement consumption and type of heating wire. As a result of calculations, the values of the required power for heating concrete of monolithic structures, the number of transformers, the voltage on the transformer for heating the concrete, as well as the duration of the periods of heating, isothermal curing and cooling during the heat treatment of concrete were obtained. As a result of the performed numerical experiments, the modes of heat treatment of a monolithic floor were deter-mined, which ensure the achievement of the required strength of concrete of monolithic structures. This type of heat treatment of concrete during winter periods has established itself as energy efficient and versatile, since heating wires can be used in structures of any type, configuration and reinforcement. With the correct use of heating wires, it is possible to obtain high-quality reinforced concrete structures erected at negative ambient temperatures.

Comparison of the planned and actual course of construction of reinforced concrete monolithic structures

During construction, there is often a change in contractual terms, either in advance of construction or delayed construction. This phenomenon is due to many influencing factors such as delayed subcontracting, climatic conditions, the surrounding construction site, the quality of project documentation, the solvency of the investor, the expertise of the general contractor, etc. The aim of the paper is to assess the planned and actual construction of reinforced concrete monolithic structural elements using tower cranes. The subject of the paper is to state the expected method of implementation in time and how the construction proceeded. Milestones for accelerating and slowing down construction, analyzing their causes and proposing future measures will be presented. Data are obtained by measuring real buildings.

Monolithic in-plane integration of gate-modulated switchable supercapacitors (ipG‐Cap)

Monolithic integration of iontronic devices is a key challenge for future miniaturization and system integration, in particular the interconnection of multiple functional elements as required for ion computing. The G-Cap, a novel iontronic element, is a switchable supercapacitor with gating characteristics comparable to transistors in electronic circuits, but switching relies on ionic currents and ion electroadsorption. We report here the first monolithic in-plane G-Cap integration through 3D-inkjet printing of non-toxic nanoporous carbon precursors. The printed G-Cap has a three-electrode architecture integrating a symmetric "working" micro-supercapacitor (W-Cap) and a third "gate" electrode (G-electrode) that reversibly depletes/injects electrolyte ions into the system, effectively controlling the "working" capacitance. The printed precursor structures were directly converted into nanoporous carbon materials with a specific surface area of 544 m2 g−1. The symmetric W‐Cap operates with a proton conducting hydrogel electrolyte based on PVA/H2SO4 and shows a high capacitance (1.3 mF cm−2) that can be switched “on” and “off” by applying a DC bias potential (- 1.0 V) at the G-electrode. This effectively suppresses AC electroadsorption in the nanoporous carbon electrodes of the W-Cap, resulting in a high capacitance drop from an "on" to an "off" state. Printing offers far-reaching freedom of design for varying the device structure achieving superior device performance. The new monolithic structures achieve high rate performance, reversible on-off switching with an off-value as low as 0.5 % surpassing values reported so far. Establishing technologies and device architectures for functional ionic electroadsorption devices is crucial for diverse fields ranging from microelectronics and iontronics to biointerfacing and neuromodulation.

Radiation protection technologies using granular materials

Technological overcoming of the potential threat of a decrease in the quality of radiation monolithic structures of protective shields, which are under constant influence of ionizing radiation (due to radiation embitterment) is one of the most urgent tasks of ensuring protection against radiation exposure. The aim of the work is to carry out a comparative analysis of the quality (in terms of radiation protection) of monolithic and granular protective screens. In contrast to monolithic prototypes, granular conglomeration has clear advantages, which are to avoid destructive processes of radiation embitterment, simplify replacement and handling (compaction and compaction), and disposal. It is important to emphasize that the protective properties of granular screens hardly differ from their monolithic counterparts, and the economic advantages of the corresponding technologies are significant at the same time. The material provided is actually the formulation of the problem on the theoretical substantiation of the advantages of using granular materials (in comparison with monolithic ones) in radiation protection technologies based on analysis as physical mechanisms and form factors of interaction neutron and gamma radiation with a substance with a developed morphology on a micro-scale.

Effects of gamma radiation on the layered structure of lithium silicon – niobate.

In this work, it is shown that when an ionizing radiation pulse acts on surfactant-type devices in which a silicon single crystal is deposited with a gap on a piezoelectric substrate made of lithium niobate, the output signal is distorted. It was found that, depending on the type of conductivity of the material deposited on the lithium niobate, a different character of recovery of the device parameters was observed. The effect of ionizing radiation on air-gap devices operating as a memory correlator showed that the previously recorded signals were erased at a dose rate of ≥ 106 rad. To explain these dependencies, a model is used based on the fact that photo carriers excited by ionizing radiation in the depleted layer are captured by traps at the silicon-air interface for devices with an air gap and at the silicon-silicon oxide interface for monolithic structures The presented model, which takes into account traps not at the interface, explains most of the effects that cause a change in the output high frequency (RF) signal.

Form (Exercises 81–90)

The form of a composition is generally associated with its structure and evolution in time. The duality between similarity and contrast is vital when analyzing or composing form. Exercise 81 is based on the idea of contrast between sections; the goal of number 82 is to work with music blocks or modules; 83 is focused on the concept of developing variations as a formal approach (the variation of the variation). Exercise 84 brings back the traditional concept of variations on a theme; similarly, number 85 uses the traditional rondo form as a model. In 86 the core is the use of repetition as in minimalist music; 87 proposes an exercise about palindromic formal structures. Based on Earle Brown’s Available Forms, number 88 proposes a framework to challenge the idea of musical form as a fixed entity; 89 is about composing monolithic structures. The last exercise of the chapter, number 90, offers the opportunity to compose and explores ruled-based game compositions.

Influence of climatic factors on the properties of ballistically resistant organoplastics

Ballistic-resistant organoplastics made from layers of aramid fabric, adhesively bonded by a binder film, exhibit an increased tendency to absorb moisture, water and technical fluids in comparison with organoplastics monolithic structures. The absorption of liquids is anisotropic and manifests itself most intensively through the butt ends of the samples. The use of protective paintwork ensures stability of the characteristics of ballistic-resistant materials when exposed to environmental factors (environment, water, fuel, oil, natural climatic conditions).

Selection of formwork systems for arrangement of monolithic columns according to the method of integer rating of laborability and process duration

The relevance of this article is related to the problem of standardization of technological processes in which there is construction equipment for concrete work. Almost all construction processes are performed using construction equipment. The arrangement of monolithic structures is accompanied by the processes of installation and dismantling of the formwork. It is impossible to make a reasonable choice of options for equipping construction processes according to the existing standard time norms. For all possible variants of column formwork, almost the same time norms are used [1]. The article considers the comparison of several formwork options for the installation of monolithic reinforced concrete columns of frame structures. To determine the duration and complexity of the process used the method of integer rationing [2], which allows taking into account even minor changes in the formwork. Calculation by this method makes it possible to select the most effective options for formwork. As a basis, this technique uses an analysis of the number of actions and responsibilities of these actions in relation to the quality of the process and its reliability. Any construction equipment is characterized by structural and technological versatility, which also affects the choice of options conditions of the process, so the article provides an analysis of these factors in terms of quality. If in the structure of the structure there are columns with different cross-sectional dimensions or heights, the preference is given to formwork options with greater structural versatility. The material of the article opens a whole direction for further research in the field of construction equipment in other processes.