Volume 19, Nº 4 (2018)

In this article the authors collected and analyzed data on the cost of second housing in the city of Krasnoyarsk in 2017. The number of the objects for analysis accounted for 1609 apartments. The authors considered the quantitative characteristics of one-room, two-room, three-room and four-room apartments. The purpose of the work is to identify the factors that have a significant impact on the formation of the price of the apartment, and build a dependence of the cost of the apartment on these factors. The mathematical apparatus for the analysis of the considered dependences is correlation and regression analysis. Because of the significant spread of data, this array is divided into groups of apartments with different number of rooms. The results of statistical analysis of the obtained sets are presented in the form of frequency histograms. The indicators that affect the cost of the apartment are analyzed. It is shown that only 4 factors are essential: a floor, a total area, a living room and a kitchen. The calculation was performed using MS Excel. The main statistical characteristics for each sample were calculated in the article. On the basis of these characteristics statistical conclusions about the nature of the distribution of populations were made. The authors showed that the median for one -, two-and three-room apartment complexes is slightly less than the average value of the sample, the fashion is slightly less than the median, and there is no long tail of the distribution. And the average value reflects the ”Central value”. The distribution curve has a higher and sharper vertex than the normal distribution. For one-room and two-room apartments the difference between the average costs of one square meter is not statisti- cally significant. Therefore, in groups of one-and two-bedroom apartments average prices per square meter are ap- proximately equal. The same effect is for a pair of two-bedroom and four-bedroom apartments. In other pairs differ- ences are statistically significant. The analysis shows that the most frequently offered for sale apartments have a cost close to the average. When dividing a set of apartments into groups by the number of rooms, samples are obtained, the empirical distributions of which are close to normal and, accordingly, the construction of regression models for such sets is justified. The study confirms the high impact on the price of the apartment offered for sale, the total area and the moderate influence of other factors. The constructed models adequately describe the experimental data.

Nowadays tree modeling algorithms are used in different fields of activity: from computer games to the plantation forest management. Tree modeling algorithm parameters can depend on different factors: it could be features of land- scape, climate or geographical location. Depending on the tasks to be solved, the detail level of the created model is chosen. Forest management tasks often do not require a high detail level, it is sufficient to construct a schematic plantation model. For computer games the creation of photorealistic models is required. The paper proposes an algorithm of 3D tree modeling which consists of the following steps: first step - building a tree framework (modeling the growth of a tree and adding new nodes), while under the framework is meant a set of three-dimensional vectors with attributive data for each vector; then building a tree and overlaying textures. The trunk and branches of the modeled tree are approximated by truncated cones, the axes of which are the vectors of the frame. The tree model constructing algorithm is iterative. Every iteration is a tree growth stage. Thus, the tree is gradually grown to the required level. The developed algorithm allows modeling trees of different state categories. The feature of the proposed algorithm is the possibility of constructing a three-dimensional tree model with any detail level. For example, for coniferous trees it is possible to built a tree up to each needle.

The purpose of developing a method for detecting quality anomalies of interactive electronic technical manuals (IETM) in application to aircraft maintenance and repair is an objective, purposeful interpretation of assessment of the specified quality. This method is a combination of the corresponding logical-mathematical model of such anomalies designed for subject content logic circuits (SCLC), and the algorithm of its performance in the technological process of compiling interactive electronic manuals. The IETM model of quality anomalies provides the analysis of the SCLC structure as some basic graph and regards the anomaly as a more specific graph. The specific graph is a graphical description of various partial distortions of the logic presented in the form of SCLC. Such a representation of quality anomaly of IETM for aircraft maintenance and repair - by a graph isomorphically nested in the structure of its SCLC - allows to reduce the detection of such anomalies to the mathematico-algorithmic problem of detection or search for the corresponding isomorphic subgraph in the configuration of the corresponding logic circuit. This allows to detect persistable structural embeddings charac- terizing logical errors in the feeding of electronic content to IETM for aircraft maintenance and repair from the list / database of predetermined anomalous logic substructures. The proposed method for detecting IETM quality anomalies in application to aircraft maintenance and repair is both a methodological toolkit and an extensive basis for design of suitable software models for automatic procedures of valid structure and content correction in concrete interactive electronic technical manuals.

We have developed a linear model for compiling and optimizing food components in a bioregenerative life-support system (BLSS) intended for space purposes in the Excel environment using OpenSolver public add-in with COIN-OR- CBC solver. The independent variables in the model are the masses of ingredients used in dishes. The objective functions of modeling are to minimize the total mass of the daily diet and maximize its antioxidant potential. The daily intakes of nutrients in the menu are limited to NASA standards. The upper and lower limits are also imposed on independent variables and the masses of dishes. We have found the content of nutrients in ingredients in open databases. The menu includes the first course, the second course, snacks, desserts, drinks, bread and water. We have presented an example of a concrete calculation of the daily menu consisting of 12 dishes: fresh-soup, chicken with rice, the roast, sausages, tofu, chickpeas, candied nuts, bread, goat milk, soy milk, cocktail and water. These dishes are prepared using 24 ingre- dients: table salt, water, wheat grains, rice, quinoa, millet, sweet potato, white potato, carrots, safflower oil, soybeans, chickpeas, lentils, cowpeas, strawberries, tomatoes, onions, garlic, chili pepper, quail, pork, tilapia, goat’s milk and sugar. The ingredients being used represent edible biomass of plants and animals that are candidates for inclusion in BLSS. Caloric content of a daily diet is assumed to be equal to 2800 kcal. It is shown that food imbalances in the esti- mated daily menu are caused by a shortage of estimated daily intake of pantothenic acid, and also by an excess of iron, phosphorus and saturated fats. Excess intake of iron and phosphorus may not be critical for the health of the users of BLSS. The minimum weight of the daily menu is 2641 g, and its antioxidant potential can reach 14 mmol Ttrolox- equivalent.

Cavitation is a process of formation of vapor bubbles within a liquid at low pressure regions. There are strain ten- sions at low-pressure region, which lead to a gap, producing cavitational cavities. These cavities contain vapor bub- bles. When cavities come to a high pressure region, they collapse, leading to a local water hammer which is able to erode the surface of a centrifugal pump. The occurring and the evolution of cavitation in liquids bound to the existence of so called cavitational cores. A physically pure liquid can resist to a strain tension efficiently, however industrial liq- uids always have cavitational cores. The cavitational cores are undissolved gas inclusions. The acceleration of evolu- tion of cavitation depends on free and dissolved gases and thermodynamic properties of liquid as well. Cavitation brings three negative factors to the performance of a centrifugal pump: performance failure - an abrupt decreasing of main parameters; erosion corrosion; low-frequency pulsations that cause the unstable work. Every centrifugal pump goes through cavitational tests for the determination of the cavitation performance. How- ever, the contemporary test methods do not have the required accuracy; moreover, the duration of a test is bigger than the work time of a pump in a rocket engine. The paper has the suggestion of the accelerated method of cavitational tests. To get the results, the new method works without maintaining of the mass flow rate, but with increased pressure-change speed on the pump entrance. For the decreasing of the error, the new method includes automatic measuring system. The authors have determined that the accelerated method with automatic measuring system does not influence the accuracy, but in the same time makes the test process shorter in time and easier to accomplish.

The paper presents the results of creating and researching the transparent heaters with enhanced performance characteristics. The heaters are based on a composite coating of a new type by contrast with classical solutions based on transparent conductive oxide films. Such a composite coating is copper micromesh obtained using a self-organized template, stabilized by a thin film of graphene oxide (GO). The micromesh coating is formed by magnetron sputtering of copper onto a template obtained as a result of self-organized cracking of a silica film. Then, a graphene oxide film protecting the micromesh coating from thermal and chemical degradation is applied to the micromesh coating by the spray-method. A composite coating with the surface resistance of 8.9 Ohm/sq is obtained with the transparency of 82.8 % at the wavelength of 550 nm. High uniformity of heating and stability of the composite coating are shown when operating under heating up to 97.2 °C for a long time (24 hours). The composite coating of the GO / Cu micro- mesh on a glass substrate 2 mm thick is characterized by the thermal resistance value of 134.2 °C·cm2·W-1, while the ITO literature sample on an equivalent substrate is characterized by the thermal resistance of 94.04 °C·cm2·W-1, which indicates higher heating efficiency at the same specific power dissipation. This fact opens up prospects for its use as an anti-icing coating in aerospace industry.

An electrostatic model of conducting nanopore is presented in the paper. The model does not require solution of the Poisson equation for the potential. This model is intended for use in simulation of transport phenomena of charged par- ticles in conducting nanopores by the method of molecular dynamics. This method is based on Newton’s equations of motion and it allows one to determine the variation of position, velocity and acceleration of particles with time. The electric field from the charge distributed over the nanopore surface is approximated by the field from fictitious point charges on the same surface. To verify the proposed model of fictitious charges system capacitance is calculated. The obtained values of capacitance are compared with classical results for conducting tubule and with the results obtained by the other similar method. The comparison shows that relative discrepancy between results is less than 10 %. There is a need to further develop the proposed model both in case of a large number of fictitious charges and in case when charged particles are in close proximity to the nanopore surface. The proposed method can be easily applied to an ar- bitrary shape nanopore. The model can be used in the development of various nanodevices, among them the devices used in life support systems of manned space vehicles.

The Institute of Biophysics SB RAS is developing a physical experimental model of a closed ecosystem (EMCS) simulating mass-exchange flows in the presence of a calculated proportion of human metabolism. The model is de- signed to check the compatibility of the higher plant link with the biological and physicochemical links in the process- ing of organic wastes that are being developed. In this connection, the EMCS does not contain a number of auxiliary reactors (decomposition of urea, nitrification of ammonia and synthesis of hydrogen peroxide), the direct interaction of which with the plant link is either excluded, or do not have a negative impact on cultivated plants. The absence of these reactors leads to an imbalance in the flow of substances in the system; in particular, excess oxygen is formed as a result of the process of “wet combustion” of organic wastes in hydrogen peroxide. To compensate for the model gas balance, a special gas circuit is developed in which oxygen is removed by binding to hydrogen obtained by electrolysis of off- system water. To control this process, an automatic gas concentration monitoring system has been developed that allows maintaining the concentration of hydrogen in a safe range without an operator's presence, stopping the process by achieving the required oxygen concentration, and also recording the sensor readings into the database for further processing. In addition to the proposed methodological approach, the developed control system can be used in full- scale biotechnical life-support systems to monitor the oxygen / hydrogen composition of a gas medium in a gas circuit of other physicochemical processes, for example, in the synthesis of hydrogen peroxide and ammonia nitrification.

The paper presents a general description of the production process of pipelines of complex configuration (TSC). Narrow directions and specializations that take a significant part in the manufacture of spatial piping systems (PTS) and fundamental technologies in this process are described on a multilateral basis. The object of the description is a base module of the upper stage (BMRB), which has both a civilian purpose - output of the payload by missiles carry- ing medium and heavy classes to a geostationary orbit, trajectories, and a special purpose. The subject of the descrip- tion is a methodology of the pipeline bending process. The article is divided into introduction, four sections describing this process and conclusion. The beginning of the article provides a rationale for the relevance of the topic under con- sideration, the strategic importance of the industry and the goal. The state need for BMRB for heavy launch vehicle “Angara-A5” for the next decade is determined. The functional assignments of the BMRB pipelines and the influence of the operating parameters of the components in the pipelines on their dimensions and material are described. The proc- ess of preparing the production technology of the pipeline is divided into nine stages: the receipt and study of design documentation (CD) in the form of 2D drawings with technical requirements and dimensions; design modeling of a part in a 3D model; definition of equipment manufacturing parts; technological preparation of the pipeline for bending; the operation of the direct manufacture of the preliminary product - the standard; measurement of the size of the resulting standard; analysis and solution of the possibility of further use of the standard; adjustment of the program of a flexible machine with numerical control (CNC) through the correction factors; assembly of the pipeline as part of a complex pipeline using a pneumatic-hydraulic scheme (CBC) with a directive technology approval. An algorithm for construct- ing a pipeline model is described; it is divided into nine main stages. Then a general description of the software module for a CNC machine and flexible pipelines are given. An international standard governing the development of a software module for CNC machines with a brief description of the sequence of preparatory and auxiliary commands is consid- ered. A block diagram of creating a control program for a pipe bending machine is shown. In conclusion, the promising directions of the development of the technology of flexible TSK are shown, in particular through the introduction of new equipment into production: universal technological interception of pipe bending; special bending head with induction function, as well as through the creation of a universal process technology of flexible TSK allowing not to resort to the creation of new technological processes for pipelines of different diameters, lengths, materials and taking into account the features of the machine .