Vol 19, No 4 (2018)

Mechanical engineering and power-plant
Large-sized transformable space antenna reflector made оf composite materials dynamic modeling process
Reznik S.V., Chubanov D.E.
Abstract

Large space structures (LSS) occupy a special place among other objects of space technology. Due to their large size, these structures are compactly stowed under the fairings of the launch vehicles or in the cargo compartments of the Space Shuttle type spacecraft. After launch into the working orbit, they are deployed automatically into the predetermined configuration with the help of transformable elements, which act both as the load-bearing frame and actuators. The deployment should be carried out within the specified time and should not negatively affect the strength, shape or spatial orientation of the structure. To meet these requirements, it is necessary to theoretically investigate the deployment dynamics of the LSS under consideration. This paper aims to find the optimal design and engineering solutions of an ultralight transformable reflector for a space antenna made of metal mesh with load-bearing elements in the form of telescopic hollow rods made from carbon fiber reinforced plastic. The deployment dynamics of the load-bearing elements with the mesh attached was modeled using the Russian-made software package EULER 10.25. The modeling allowed us to estimate the effect of the tensile load from the mesh on the deployment process. With the elastic load from mesh accounted for, the stability and rigidity of the load-bearing elements will be ensured and the accuracy of the mesh tension will be increased.

RUDN Journal of Engineering Researches. 2018;19(4):411-425
views
Reserves for improving the design of shafts
Kirilovskiy V.V.
Abstract

Shafts are used in almost all machines and mechanisms. Unlike other parts, the destruction of the shafts is very rare. As it was supposed earlier, it is connected with high level of perfection of a technique of their calculation and design. The article analyzes the features of the three traditional methods of shaft design and shows that the shafts are not destroyed for the reason that traditional methods lead to a significant, up to 27 and more times, overestimation of the diameters of all the characteristic areas in comparison with the size sufficient in terms of the strength of the shaft. The area of its cross-section and, accordingly, the mass can be overestimated by more than 750 times. Such unjustified overestimation of the shaft diameter and weight cannot be considered as an indicator of the perfection of the shaft design and calculation methods, and, on the other hand, is an important reserve for the improvement of their designs. This is particularly true for those mechanisms that are subject to increased requirements in terms of minimum size and weight.

RUDN Journal of Engineering Researches. 2018;19(4):426-437
views
Architecture and civil engineering
Classification of analytical surfaces as applied to parametrical architecture and machine building
Grinko E.A.
Abstract

At present time, the architects began to show interest in the creation of space large-span shapes due to advent of new materials and building construction technologies. Increased ergonomic requirements for structures and erections are now a great significance. This approach can be seen in many projects, both implemented in material and still being at the stage of drafts and blueprints. Now in economically safe countries, there has already been a splash in the creation of new unique structures, including spatial ones with complex surfaces. It is necessary to prepare for such prospect also in our country. Currently, a large number of surface classifications is offered, but they do not cover the all variety of known surfaces. This article introduces a classification of both new and widely known surface shapes as applied to the structures of building and industrial purposes. A detailed classification of analytic surfaces of 38 classes is constituted. An extensive bibliography containing 40 references is presented for convenient search of studies in the field of geometry and strength analysis of thin shells with the non-canonical middle surfaces.

RUDN Journal of Engineering Researches. 2018;19(4):438-456
views
Design of universal attractive transport passage Sundarbans over the Bay of Bengal
Qazi S.S., Shuvalov V.M.
Abstract

The purpose of this article is to find new ways to develop the recreational and tourist potential of Bangladesh. One of the methods of solving this problem is the construction of a universal attractive transport passage Sundarbans over the Bay of Bengal, where land transport is poorly developed due to frequent river spills. In this regard, the proposed option of building a modern bridge with developed infrastructure and with the use of modern technologies and materials, which will unite the regions of Chittagong, Barisal, Khulna. The construction of entrance infrastructure facilities and multifunctional transfer centers in the cities of Khulna, Bhola, Barisal, Chittagong, Noakhali, Koh Bazaar will attract additional flows of tourists, which will unite the regions of Chittagong, Barisal, Khulna. Methods. The article deals with the factors influencing the development of recreational and tourist potential of Bangladesh. A review of the main problems encountered in the construction. The search for the disclosure of reserves for development is planned. Conclusion. A rational and economical solution will allow the complex to organize the further operation of the structure, turning it into the main recreational and cultural center of the region, responding to the objectives of the future development of recreational services Bangladesh up to 2030. This requires further development of transport communications in the southern part of the country between the regions of Chittagong, Barisal, Khulna.

RUDN Journal of Engineering Researches. 2018;19(4):457-470
views
Consideration of climatic conditions in the design of dwellings in the Sahara desert
Benyoucef Y.M., Razin A.D.
Abstract

Climate is one of the important factors in architecture. The historical architecture experience of the inhabitants of the desert zones has created invaluable knowledge on the design of residential environments in these aggressive conditions. Climate also is an important ecological component in the formation of vernacular architecture in the Saharan desert, it had a strong influence on the formation of desert settlements, the Saharan traditional dwellings are an indispensable source for studying organizations and architectural typologies and the adaption to the harsh climate. The article discusses the climatic conditions in which the dwellings in the Sahara desert were built and the important strategies and passive climatization techniques of the design of the dwellings and presents a review of the various techniques developed. These various passive methods and strategies give the Saharan dwellings, adaptation, efficiency, and durability in these hot-arid conditions of the desert and can be a great source of architectural inspiration for new projects.

RUDN Journal of Engineering Researches. 2018;19(4):471-481
views
Innovative use of mineral resources
Forecast of areas of distribution of gas hydrogat deposits on geophysical data in the Gulf of Guinea
Abramov V.Y., Mamadou D., Romero M., Aljabasini H.
Abstract

The article displays information about the Gulf of Guinea and presents the results of gravity anomalies calculations for the forecast of the probable discovery of gas hydrate deposits on the shelf of Cote d’Ivoire by analogy with the shelf of Brazil. Similar features of the geological structure and geophysical anomalies on the shelf sections on different sides of the Atlantic Ocean are shown. The main problem in organizing the search for gas hydrates on the shelf of the Gulf of Guinea is political instability, as well as the lack of funds for research in the Ivorian shelf. And because of the complexity of the extraction of oil resources, all major deposits in the country are conducted by international firms. Despite the low level of oil and gas production, Côte d’Ivoire retains prospects in the future to be an exporter of oil and gas (including gas hydrates), since the country’s sedimentary basin is still very little studied. The coverage of this issue is relevant due to the lack of such information in Russian, and the information available in English and French does not allow to form a general picture of the oil industry complex of the Republic of Cote d’Ivoire. In this article, the forecast of new sites, promising to detect gas hydrate deposits on the shelf of Côte d’Ivoire, and can be used in the allocation of promising areas for new geological studies.

RUDN Journal of Engineering Researches. 2018;19(4):482-492
views
Characterization of the rock mass of the Boukhadra mine (Algeria)
Lamamra A., Kotelnikova E.M., Sergeev A.O.
Abstract

Currently, the calculation of the sustainability of the mountain range is one of the main tasks during the design of underground structures at the Bukhadra ore deposit. Each technique involves its own calculation and classification of categories of sustainability. This article presents the results of our research. As a result of laboratory studies, the physical properties of the samples were studied. For each sample, the density, porosity, the degree of saturation of the soil with water, and the degree of cracking of rocks were determined. As a result of the research, it can be concluded that the rocks of the Bukhardra iron mine are very resistant to various factors. A classification developed by the Norwegian Geotechnical Institute to classify mountain ranges and predict further work was used to analyze the rocks of the Bukhadra iron mine. It should be noted that in order to understand the variability of the strength characteristics of the ore, the rock strength index is used. It is a leading indicator of poor quality rock zones. According to the physico-mechanical tests in the laboratories, it was noted that the Bukhadra mine massif has good resistance to compression, tension and shear, this suggests that stability problems in this field are associated with technical factors, such as surface and underground mining.

RUDN Journal of Engineering Researches. 2018;19(4):493-502
views
Special aspects of catagenetic sulfate accumulation in Permian sedimentary sequences of Central Russia
Georgievskiy A.F., Bugina V.M.
Abstract

The scope and the role of the secondary (catagenetic) processes in sedimentary-rock formation belong to the category of incompletely resolved and, therefore, the urgent problems of lithological science. The purpose of this work was to show, by means of stadium analysis, the huge “hidden” potential of catagenetic processes in the transformation of the mineral composition of sedimentary strata on the example of sulphate complexes. Boundary clay and carbonate sediments of Urzhumskiy and Sakmarskiy stage of Western limit of the pre-Ural trough were selected as the objects of study. It was found that their lithological appearance has been largely shaped by secondary (diaand catagenetic) processes of sulfate mineralization. And, if the first is reflected in the development of scattered concretionary nodules of gypsum, the latter manifested in large-scale metasomatism with the formation of large anhydrite-gypsum and gypsum-anhydrite lens and tabular bodies, stretching for hundreds of meters. It’s possible that metasomatic solutions were very reactive and moved with underground waters. Those solutions were as aggressive as lateritic weathering, and replaced not only the carbonates, but clay and ferrous minerals as well as quartz and feldspar detritus. All of this points to the high alkalinity and to the reducing atmosphere of sulphate of metasomatic solutions.

RUDN Journal of Engineering Researches. 2018;19(4):503-512
views
Influence of the El Niño phenomena on the climate change of the Ecuadorian coast
Campos Cedeno A.F., Mendoza Alava J.O., Sinichenko E.K., Gritsuk I.I.
Abstract

The climate on the Ecuadorian coast depends mainly on the marine currents of Humboldt and El Niño, which appear in the dry and rainy seasons, respectively. The Humboldt current is distinguished by being cold, while that of El Niño is hot. The presence of the El Niño current causes an increase in the evaporation of ocean waters with the consequent appearance of the rainy season. There are anomalous seasons of the El Niño stream, when the water temperature rises above the norm, higher than 25.5 °C, which has been called El Niño phenomena. The appearance of this natural phenomena has proven to be decisive in the climate change of the coast of Ecuador. In order to have technical information, important for the planning, control and development of the water resources of the DHM, in this research a temporal analysis of the monthly rainfall during 55 years, 1963-2017 period, is carried out. The National Institute of Hydrology and Meteorology of Ecuador (Instituto National de Meteorología e Hidrología - INAMHI) at station M005, located in the Botanical Garden of the Technical University of Manabí in Portoviejo, obtained these records. An analysis of the monthly and annual patterns is made, establishing that the El Niño events occurred in 1983, 1997 and 1998, have established guidelines for the change in the production of rainwater in the levels of intensity and temporal distribution, increasing the months of drought, while precipitation levels increase, concentrating in fewer months, basically in February and March. This is a situation that increases the water deficit, especially when there is not enough infrastructure of hydraulic works for the storage and regulation of runoff.

RUDN Journal of Engineering Researches. 2018;19(4):513-523
views
Modern topographic devices and electromagnetic waves: impact on accuracy of measurements
Degbegnon L., De Souza M.C.
Abstract

Precision topographic work is done by the means of classical instruments such as highprecision levels, theodolites and distance-meters. This method gives accuracy results of ±2 mm in altimetry and better than ±5 mm in planimetry, but it requires a lot of expenditures and a long time of execution and more staff. Nowadays, the constellation of the GNSS satellite positioning system and the improvements to electronic tachymeters can provide solutions to gaps in auscultation using conventional measurements. However, these methods also present their weaknesses, resulting by this way from their uses under the high voltage lines. The study of the influence of electromagnetic waves on high-voltage lines on topographic devices allows observations made with a GNSS receiver to be made from an electronic station or total station or with the aid of optical-mechanical theodolite to analyse and interpret the quality of the data obtained on the ground in the Maria Gléta zones in the municipality of Abomey-Calavi and Araromi in the municipality of Sakété. This makes it possible to present the effects of high voltage cables on these measurements and the determinations made in topometry. Very important on measurements at the GNSS receiver and at the total station, the actions of the electromagnetic waves evolve with the variation of the temperature.

RUDN Journal of Engineering Researches. 2018;19(4):524-536
views
Mineral composition, textures and gold habit of the Hamama mineralizations (Central Eastern Desert of Egypt)
Mahmoud A.S., Dyakonov V.V., Dawoud M.I., Kotelnikov A.E.
Abstract

Mineralization in the Hamama area exists mainly as quartz-carbonate veins, extending along the contact between the footwall volcanics (basalt, dacite, and rhyolite) and the hanging wall volcaniclastics (laminated, massive and lapilli tuffs with minor breccia). Also, mineralization was recorded as low mineralized cavity filling dolomitic veins occupying NW-SE faults in the basalt. The principal mineralization is represented by a mineral association - quartz + dolomite + calcite + pyrite + chalcopyrite + sphalerite with varying amounts of barite, cinnabar, and galena. It is suggested that these carbonates are post-tectonic low-temperature hydrothermal solution (exhalations) filling fault zones. The injected mineralized carbonate solution dissolved the silicate minerals along contacts. This fault system was caused by the group of porphyritic rhyolite dykes extending NE-SW. The carbonates then were subjected to digenetic processes after their formation resulted in the formation of some secondary sedimentary textures (for example spherulitic, colloform and cockade textures) and dolomitization. The mineralized carbonates are rich in Zn, Cu, and occasionally Pb and Sb. The cavity filling dolomitic veins within basalt show low concentration of ore minerals. The pyrite was crystallized in four phases; the first phase is well-developed pyrite that was formed from the primary hydrothermal solution. The role of bacterial action is obvious in the formation of a second phase framboidal pyrite. The third phase represented by atoll structures formed by diagenetic reworking of the framboidal pyrite. The last phase of pyrite crystallization appears as fine skeletal grains mostly attached to sericite alteration of altered volcanics. The gold and silver are concentrated mainly in the upper iron cap. Secondary supergene enrichment of gold in the oxidation zone, especially in Hamama western zone, is indicated by the reprecipitation of gold as thin filaments or rounded nano-grains along cracks of the oxidized pyrite or at the periphery of the pyrite relicts.

RUDN Journal of Engineering Researches. 2018;19(4):537-551
views

This website uses cookies

You consent to our cookies if you continue to use our website.

About Cookies