Vol 19, No 3 (2018)

The article considers the variation of heat pump (HP) compression parameters which define its effectiveness: power and coefficient of conversion (μ) on off-nominal modes of operation. Taking into account that the parameters of low-potential sources of heat for HP change, the demand for thermal energy also changes; study of HP operating on off-nominal modes is relevant. To analyze the operating process on partial power modes of HP, a reciprocating compressor is used. The following options are examined by authors as conditions of HP transitioning to the off-nominal mode: change in temperature of water at the condenser inlet; change in flow rate of water passing through the condenser, change in flow rate of the working medium. Based on the analysis of relationships for determining the coefficient of conversion and power consumed by HP, it is shown that these parameters change if HP transitions to off-nominal mode. The increase of temperature entering the condenser leads to decrease in μ, and with temperature decrease μ increases. Decrease in flow rate of water cooling the condenser moves the beginning point of compression of the working medium to higher moisture region and reduces the efficiency of the compressor. Working medium flow rate decrease virtually does not affect the Carnot cycle efficiency and μ decreases because of rising moisture of gas.

The article presents the author-developed software products that are used for training college and university students in engineering, economy and information fields. For training mechanical engineering professionals, the authors have developed two sets of programs. The first set is designed for mechanical engineering majors and is dedicated to studying manual programming for developing control programs for CNC machine tools, operating in absolute and relative coordinate systems. On the basis of the first program, a table of contour coordinates of a part made from sheet material is prepared, and on the basis of the second program - a table of contour coordinates of a shaft (rotary body) is prepared. The second set of programs also consists of two programs dedicated to product quality assessment - “Pareto Chart” and “Program for calculating statistical parameters for product quality control”. These programs are designed to construct Pareto and Shewhart charts based on the loaded data, allowing to learn not only basic concepts, but also learn how to compare results and draw conclusions about product quality. The next program “Analysis and design of logic control systems” is intended for Information Technology professionals, but can be applied to any field, as it gives a general picture of how logic elements operate, as well as the tasks of analysis and design. The first three tasks allow to learn logic elements, and the last task is the problem of designing logic control systems and presents a virtual device for generating input data for the design problem. The program “Development of the software product for routing cargo on the basis of the Svir algorithm” is developed for training professionals of economic specialty and allows to build maps of operating areas and task schedules on the basis of the loaded data. The above author-developed products allow the user to obtain knowledge and skills in studying specific disciplines, saving time and resources for the teacher, and increase interest in learning among students.

The article presents the physical significance of the study of axially loaded steel compression members and the origin of accepted analytical models, which are the basis for the methods of their calculation in current building codes of CIS and European countries. An approximate solution of the problem of eccentrically loaded elastic compression member is given and analytical relationships for determining the buckling coefficient as a result of solving an analytical problem and as a result of applying building codes are obtained. Based on the results from solving the structural analysis problem, a solution for axially loaded compression member buckling coefficient, which is the ratio of such stress value from axial compression to the yield stress of steel at which the outermost fibers of the cross section yield, is given. When obtaining the solution of the buckling coefficient for axial compression, it is justified that the clarity of obtaining a solution is achieved by introducing the number Pi in place of the numerical values. It is indicated that the reason for shifting relative eccentricity from the ideal value of 0.2 is the impossibility of buckling at small slenderness ratios. It is justified that the calculation methods described in Eurocode and the building code of Russia (SNiP), despite the difference in the definition of nominal slenderness ratio, have common physical significance and their difference is only in approaches to the definition of random eccentricity. The building code approaches to calculating relative eccentricity included in buckling coefficient are stated and analyzed and their physical significance is described. The significance of relative eccentricity which is included in European and Russian codes is unfolded and the relationship between relative eccentricity and imperfections in the shape and type of cross-section is indicated. The significance of the imperfection factor in accordance with EN 1993-1-1: 2005 which depends on initial imperfections, the shape of the cross-section and the technology of member manufacture is explained and the application of approximating linear function, which reflects the technological factor of precision of manufacturing and inevitably arising imperfections, is justified. The significance of the coefficients of imperfection α and β, which are included in the Russian building code for steel structures, is unfolded.

As a result of studying geological structure of deposits located in the Koulore ore field, basic cross-section layers have been established: bedrock, transitional horizon and laterite cover. The laterite cover consists of the lower part presented by polymineral and kaolin clays and the top - the bauxite horizon - laterite cover itself, which generally contains hydroxides and oxides of iron and aluminum. The bauxite horizon has a zone structure: in the lower part of the bauxite horizon - zone of light bauxites, and in the top part of the bauxite horizon - zone of the red bauxites. As a result of microscopic study of various samples of residuum, several kinds of rocks which are characterized by similar structural and textural parameters have been identified. The rocks have been grouped by classes: gelified patterned bauxites on silt-rich mudstone, gelified bauxites on dolerites, gel-morphous bauxites with crystalloids on silt-rich mudstone, laterite bauxites (low-quality bauxites) on silt-rich mudstone, laterite bauxites (low-quality bauxites) on dolerites, ferruginous laterites - cuirass on silt-rich mudstone, ferruginous laterites of the top part of the transitional horizon on silt-rich mudstone. Lithological and genetic types of bauxites control the type and composition of aluminiferous minerals. Mineral composition of classical lateritic bauxites mainly contains gibbsite, goethite-alumogoethite, and hematite with less 1% of boehmite. Gel-morphous and gelified bauxites consist of gibbsite, boehmite, goethite-alumogoethite, hematite. Content of boehmite reaches 3% that is more than in classic lateritic bauxites. The composition of the alumogoethite depends not only on lithology of bauxites, but also on position in the residuum section.

The Niger Delta is one of the richest hydrocarbon provinces in the world. The geological structure of Niger Delta is composed of Mesozoic and Cenozoic rocks. Modern Niger Delta has distinctive basin-like geological structure that is defined by inner extensional zone of listric growth faults beneath the outer shelf, translational zone of diapirs and shale ridges beneath the upper slope, and a lower compressional zone of toe thrust structures. The delta comprises of three broad formations, namely: the Benin Formation (Oligocene to recent), Agbada Formation (Eocene to recent) and the Akata Formation (Paleocene to recent). The “Efi-Field” deposit is composed of rocks of the Cenozoic age. The geological section of the field starts from Paleogene (P1-P3), Neogene (N2) and Quaternary periods. The Cenozoic deposits are represented by rocks of the Paleogene, Paleogene-Quaternary and Quaternary periods. The prevalence along the territory is very uneven. Close to the axial part of the Niger Delta, Quaternary sediments predominate, sometimes with sedimentation of some stratigraphic subdivisions of the Cenozoic period. Sedimentation was formed under conditions of Cenozoic local regression of the ocean, as a result of which the base of the section is represented by marine geological-genetic types of sediments, and the middle and upper parts by transitional coastal-marine types of sedimentation.

The article deals with the prospects of Iraq’s oil and gas potential. It should be noted that there has not been much attention payed to the desert regions of Iraq located on the Arabian plate. However, recent studies show prospectivity of the Iraq deserts. As a result of the recent investigation of river valleys in the region, the following main morphotectonic processes were identified: rejuvenation of the river network and emergence of new river basins; division of individual rivers into two or more parts; interception of the river network. As a result of long-term field and cameral geological and geomorphological studies in the area of the Western and Southern deserts, it was possible to reconstruct the existing tectonic activity of the area from the Miocene period to the present day. It is established that the regional Euphrates fault on the territory of Iraq occupies an exceptionally important place, which was previously underestimated. Adjacent echelon faults of the following order formed a system of pre-existent tectonic blocks with different kinematics and morphology. The causes and mechanism of neotectonic Neogene-Quaternary movements of the earth’s surface are established. Thus, separate tectonic blocks are identified, which generally form zonal regions of uplifts or valleys. The areas of elevated blocks (for example, the raising of Al-Najaf Al-Ashraf of the third order) are created by plicative dome structures in the cover near the Euphrates fault, favorable for the accumulation of HC.

The article deals with the prospects of Iraq's oil and gas potential. It should be noted that the desert areas of Iraq, located on the Arab plate, did not pay much attention. However, recent studies show the promise of the desert Iraq. As a result of the study of modern river valleys in the region, the following main morph tectonic processes were identified: rejuvenation of the river network and the emergence of new river basins; the division of individual rivers into two or more parts; interception of the river network. As a result of long-term field and cameral geological and geomorphological studies in the area of ​​the Western and Southern deserts, it was possible to restore the existing tectonic activity of the area from the Miocene to the present day. It is established that the regional Euphrates fault on the territory of Iraq occupies an exceptionally important place, which was previously underestimated. The faults of the following order that set him on formed a system of long-lived tectonic blocks with different kinematics and morphology. The causes and mechanism of geotectonic Neogene-Quaternary movements of the earth's surface are established. Thus, separate tectonic blocks are formed, which in general form zonal regions of uplifts or valleys. The areas of elevated blocks (for example, the raising of Nadjaf of the third order) are created by the dome-shaped dome structures in the cover near the Euphrates fault, favorable for the accumulation of HC.