On Modelling of Influence of Air Condition of Building on Gas-Consuming Equipment with an Open Combustion Chamber FunctioningSargsyan, S V; Jila, VA
doi: 10.1088/1757-899X/463/3/032001pmid: N/A
Nominal operation of gas consuming equipment with an open combustion chamber installed in the various purposes buildings’ premises depends on the receipt of the required amount of air to ensure the complete combustion process. The supply of primary air in an amount of 40-60% of the theoretically required volume allows a stable process of gas combustion. In this case, flame separation is prevented. Requirements for safe operation of the gas consumption system are satisfied. For reliable operation of the gas distribution system, it is necessary to provide installation of the automation devices that respond to any deviations in gas burners. In the process of gas fuel burning, two cones are formed. The internal cone in which the gas burnt is provided by the primary air. In the outer cone of the flame gas is burnt due to air coming from the room. In the lower part of the burner, conditions are created under which the velocity of the gas-air flow and the normal velocity of flame propagation are ensured. This ensures the creation of an incendiary belt, which constantly ignites the air-gas mixture, and provides a stable and constant combustion of gas. The inflow of air into the room where the gas consuming equipment is located is through the filling of light holes during infiltration. Increasing the resistance to air permeation of filling the light apertures is performed to improve the energy efficiency of the building by means of reducing infiltration heat loss. Reduction of natural inflow through constructive non-densities in the fillings of the light apertures leads to a decrease in the infiltration process, and, consequently, to the violation of the process of the nominal functioning of the gas consuming equipment. The possibility of creating an air regulation mechanism for individual rooms and the building is considered, ensuring the influx of the required amount of air, depending on the parameters of the outside air, the air permeability of the fillings of the light apertures, and also the height of their location. Analytical dependencies that consider the effect of the air condition of buildings for various purposes on the joint operation of natural ventilation systems with an unorganized inflow in the required volume, excluding the formation of the effect of reverse thrust in the combustion products removal system are presented.
Abrasive wear of Cemented Granular Composites: Experiments and Numerical SimulationsMakarova, N V; Polonik, M V; Mantsybora, A A
doi: 10.1088/1757-899X/463/3/032002pmid: N/A
The results of earlier experimental work and numerical calculations to determine the effects of technological parameters on abrasion resistance of concrete are summarized and new data presented. The dependences of the near-surface stress-strain state on the geometric and stiffness parameters are analyzed. Particular attention paid to the stages preceding the destruction of the adhesion interaction between cement matrix and grains. Numerical calculations were carried out in the ANSYS software. This numerical model may be useful for understanding heterogeneous material behavior in terms of wear, depending on structure geometrical characteristics, material mechanical properties and interactions occurring in the near surface layer. Adhesive laws gives very interesting advantages, of which the most important is to model the evolution of damage throughout the life of the building constructions.
Effect of Gypsum Cement Composition on Tensile Fracture Initiation from a Circular Hole in CompressionSuknev, S V
doi: 10.1088/1757-899X/463/3/032003pmid: N/A
The presence of dihydrate gypsum in the original composition of cement plays a significant role in the formation of the microstructure of gypsum in the process of hydration. Any variation in the microstructure not only changes the material’s mechanical properties, but it also alters the deformation and fracture behaviour. The effects of the original composition on the initiation and propagation of the tensile cracks from the circular holes of various diameters in gypsum under compression have been studied. Test results have been analyzed in regard to the conventional, non-local, and stress gradient fracture criteria. It has been evidenced that, if the content of dihydrate gypsum in the original composition is low, then tensile crack initiation is equally well described by applying either the stress gradient criterion or the non-local criterion under consideration. However, if a dihydrate gypsum share is significant, then the application of the stress gradient criterion is preferable
Problems of a Thermal Insulation of Multystoried Cast-in-Place Concrete Frame Buildings in the Conditions of Extreme NorthKornilov, T; Kychkin, I; Slobodchikov, E
doi: 10.1088/1757-899X/463/3/032004pmid: N/A
In recent years in Yakutsk began to build residential buildings 12-16 floors high with a reinforced concrete framework. Thermovision examinations of these buildings are conducted and the analysis of thermograms of a surface of the protecting designs is made. Sites of violation of thermal protection of buildings are established and calculations of the main clusters of the external protecting designs with application of programs of a three-dimensional temperature profile are carried out. The comparative analysis of calculation datas with natural data on thermovision inspection is made. The main reasons for violation of thermal protection of the protecting structures of multystoried buildings are established. In a basement storey of buildings low temperature on an internal surface of designs is bound to existence of thermal bypass in places of an adjunction of a laying of external and internal walls to basement floor slabs, reinforced concrete columns to basement floor slabs with a foundation framework. During the winter period at especially low temperature of fresh air penetration of cold air in multystoried buildings is promoted by the increased air infiltration.
Formation of System of Scattered Fatigue Damages and Their Effect on Fracture of Structural Silicon SteelBuslaeva, I I; Yakovleva, S P; Makharova, S N
doi: 10.1088/1757-899X/463/3/032005pmid: N/A
Forecasting of a residual life of machine elements and structures requires consideration of changes of a metal condition during operation. The aim of this article was to study accumulation of critical fatigue damage in structural silicon steel under operational impacts characteristic of the permafrost region. The metal of various zones of a failed main leaf of a truck spring, which was operated under the subarctic conditions, was investigated. It was revealed that formation of a system of volume scattered microdamages at a level of substructure and mesoscale damages in a form of fine and coarse pores ranging in size from a few micrometers to ≈40 µm preceded fatigue failure of the spring. It is shown that at a stage of material prefracture a deviation of a microhardness distribution from the normal distribution is observed. For the considered operating conditions, a determining role of presence of multiple fine pores in reducing resistance to the fatigue failure as compared to the presence of the coarse pores has been established. Results can be used in development of methods for studying the structural damage of materials and identification of fatigue failure stages.
Actual Design Technologies as a Method for Solving Problems of the First Stage of Landscaping (By Example of a Project of Implementing the State Policy Concerning the Far East Territory Development)Stratonova, L M
doi: 10.1088/1757-899X/463/3/032007pmid: N/A
The urgency of the analyzed problem is connected with a large scale project of developing unpopulated territories in the Far East. The core of the project is concluded in the allotment of one hectare piece of land for unlimited use, the target of the project is small business, farming, and tourism development, etc. The aim of the given article is to analyze the problems connected with the new territories development. The main problem is a systemless and haphazard forming homesteads and constructions. The use of projects made by young designers’ associations, student architect design teams, and industrial artists’ teams can grow into a method in solving the above mentioned problems. The main accent in this case is on a collective effort to create innovation residential areas. An example of such efforts can be the concepts developed and tested by the Chair of Art Design and Art History members: a training constructor for landscaping, conceptual models of new type residential areas “Nebo” (“Sky”) and “Priroda” (“Nature”). The models display acquiring mastery of primary skills of design, composing large scale elements, determining basic factors in interrelation of space and form, and understanding the intricacy of a problem to create a new, aesthetically ideal fragment of the world on a piece of land not large in size. The article can become a basis of the content that allows quick familiarizing with actual concepts and methods in solving problems of landscaping of individual homesteads, provided kinds of activities are taken into account. Cognitive methods for mastering design and development fundamentals, game technologies, and actual forms of visualization are to become an efficient vehicle for creating a radically new image of the Far East region.
Simulacrum as a Tool for the Design Predictive ModelingStratonova, L M; Shvaleva, O V; Trofimova, M M
doi: 10.1088/1757-899X/463/3/032008pmid: N/A
At present, problems of modernization of Russia’s image have become a subject of public discussion. The article defines some actual methods and design technologies that could contribute to the solving these problems. The target of the article is an analysis of a range of problems related to modernization tasks and a search for actual means and approaches to solving problems of the primary stage – concept developing. As a solving method there can be considered design models creating visual representation of the future – a kind of a hypothesis of how the living environment can ideally be developed on the given territory. Forms of such modeling can be different, from computer models to animation. The content is determined by the depth of the penetration into the future. It can be a project based on concrete town planning programs or a project based on serious and complicated foresights or projects of so far future that they cannot be based on any scientific experience and foreseeing. The projects created by the members of the Chair of Art Design and Art History can be regarded as results: the project of the student campus “Rubik’s Cube”, the project of the sport area “World Pravi”, suburban agricultural settlement “Cucumber”, “Few-Chernikovsk”, and many others. These design predictions are based on experimental principles of arranging urban and suburban environment. The content of the article can become a start of a bank of creative ideas of development and modernization of our territories; this will help to form common stylistic principles of creating a new image of Russia.
Ensuring Hardening of Cement Injecting Mortar at the Installation of Grout-injected Micropiles in Permafrost SoilsMatveeva, O I; Fedorova, G D; Prokopiev, R V; Vinokurov, A T; Pavlyukova, I R
doi: 10.1088/1757-899X/463/3/032009pmid: N/A
The article deals with the problems of grout-injected (bored) micropiles application in the conditions of permafrost soils. This technology is widely applied in many countries, but the complexity of using the bored micropiles in the conditions of the North lies in ensuring curing of injection mortar when being influenced not only by the negative temperatures of permafrost soil, but also by the negative ambient temperatures. Considering the fact that large-scale development of the Arctic districts of Russia has been initiated, the results of researches in this field are very relevant. For the first time in Yakutsk the technology of the grout-injected micropiles installation has been tested in the amplification of the National library building foundation conducted according to “YakutPNIIS” institute recommendations. The obtained positive results indicate the possibility and effectiveness of their application in the repair of buildings, as well as in the construction of facilities. The article presents the results of the development of injection cement mortars compositions with various additives and the kinetics of their hardening, their approbation in production conditions. The analysis and discussion of the received results confirm that the grout-injected micropiles installation technology in the permafrost conditions can be widely used, promoting an increase in efficiency of new construction and capital repairs of buildings and constructions.
On the Probability of the Development of the Diagnostic Feature of Decline the Bearing Capacity of Structures under Random Dynamic LoadsIskhakov, Sh Sh; Kovalev, F E; Zarin, S V
doi: 10.1088/1757-899X/463/3/032010pmid: N/A
The article is devoted to the problem of identifying the diagnostic feature of the structure bearing capacity decrease under random dynamic loads. The diagnostic features that characterize the decrease of the bearing capacity of structures and foundation are identified. The model of the dynamic system that describes the process of the diagnosed building structure functioning is presented. The article shows the difficulties encountered in the process of vibration diagnostics of reducing the bearing capacity of structures and foundations. It is pointed out that the output vibration signals can be recorded in the mode of displacements, velocities and accelerations. But at the same time, the probability spread of detection of diagnostic feature of the bearing capacity decrease of building elements in the energy spectra of the output vibration signals can be significant. To develop a method for determining this probability, the authors propose to use a regression analysis with the solution of the problem at three levels of “regression”. In the article the factors influencing the probability of detection the vibration diagnostic feature in bearing capacity decrease of building elements are analyzed. This probability characterizes the effectiveness of the vibration diagnostic method in monitoring systems of unique objects, including launch facilities. The authors have shown that the maximum efficiency is achieved by using systems for monitoring energy spectra of vibration accelerations at the output. At the same time, the authors conclude that the probability of effective functioning of vibration diagnostic systems is mainly influenced by such factors as the sensitivity of the vibration diagnostic method to the rigidity decrease of structures and bases. The equipment error of registration of the energy spectra of vibration accelerations is also to be taken into consideration