Islamic Copper-Based Metal Artefacts from the Garb Al-Andalus. A Multidisciplinary Approach on the Alcáçova of Mārtulah (Mértola, South of Portugal)

A multidisciplinary approach has been applied to investigate the production technology of a collection of copper-based artefacts found during archaeological excavation campaigns carried out in the Almohad neighbourhood of Mārtulah, the Islamic name of modern Mértola (South of Portugal). In stark contrast to other Islamic materials found in the same site such as common and finely decorated pottery, glass, and bone artefacts, metal objects have received less attention despite the number of artefacts recovered. This study focuses on the chemical characterisation of 172 copper-based artefacts dating back to the 12th and the first half of the 13th centuries. The artefacts are daily use objects and consist of personal ornaments (earrings, rings, and casket ornaments), tools (spindles, spatulas, and oil lamp sticks) and artefacts with unknown functions. X-ray fluorescence Spectroscopy (XRF) and Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy (SEM/EDS), provided information not only about technological issues, as well as on the socio-economic implications of metal consumption at Islamic Mértola. The results revealed that metals were produced with a variety of Cu-based alloys, namely unalloyed copper, brasses, bronzes, and ternary alloys, by mixing Cu, Zn and Sn and Pb without any apparent consistency, as a likely result of recurrent recycling and mixing scrap metals practices or use of minerals available locally.

Technology and equipment of vertical‑stack molding for the production of castings without pattern drafts

The article reports on the new technology and equipment of vertical‑stack molding (VSM), created by OJSC “BELNIILIT” for the manufacture of vertical‑stack molds. The development is intended for the production of molds and cast blanks of oil, which are later used for the manufacture of piston rings of internal combustion engines.The difference between the above‑mentioned technology and traditional methods of VSM is the use of models without drafts. The development is export‑oriented and has a great economic effect for ring manufacturers due to the absence of drafts on castings, since part of the mechanical operations for their processing is excluded, the metal consumption of blanks is reduced, the production spaces required in this regard are reduced, the necessary labor supply is reduced, etc.OJSC “BELNIILIT” has successfully carried out experimental design and technological work on the new scientific and technical products creation, which are of great interest to the world manufacturers of piston rings. An industrial sample of a molding machine and a mold manipulator were manufactured.

Methodology for calculating rope drums for stability

. The problems of the stability of rope drums are quite urgent. The rope drum is in most cases a thin-walled shell, which, under the influence of external pressure from the rope, can lead to loss of stability. The stability issues of the drum shell, which is loaded with rope turns, are very important, because the safety and reliability of the rope hoist is directly related to them The studies carried out made it possible to obtain a new method for calculating the stability of cylindrical shells, which takes into account not only the length of the shell, but also the rigidity of the connection with the head. In addition, a calculation formula was obtained to determine the critical pressure of the oval shell, which gives a fairly good agreement with the experiments of American scientists. The work also considered the effect of the difference in wall thickness on the critical load of the drum. The studies carried out made it possible to conclude that the parameters of the rope drums make it possible to completely eliminate the need to install rings and stiffeners. Also as a result of research it was found that the shell of the crane drum under the influence of a radial load cannot lose stability. Studies have shown that in all cases the stability margin of the rope drum shell is greater than the strength margin. In this case, the load created by the rope wound on the drum is considered, with the ratios of the radius of the drum and the rope typical for crane construction. In addition, a coefficient was established that takes into account the elasticity of the shell-head joint. The studies carried out have shown that such initial deviations of the drum shell shape as ovality do not give a significant increase in the critical load. The results obtained are quite important, since they allow reducing the metal consumption of the rope drum shell and at the same time ensuring its reliable operation. A decrease in metal consumption is achieved by reducing the thickness of the shell and the absence of the need to install rings and stiffeners. This will lead to a decrease in metal consumption and energy consumption of the crane itself, and also simplifies the technology of manufacturing a rope drum.

ANALYSIS OF THE EFFICIENCY OF ACOUSTIC SCREENS OF DIFFERENT DESIGNS

Various sources of noise in cities and ways to combat them are considered. The effi ciency of two types of acoustic screens is analyzed: single-layer and two-and three-layer. The positive and negative characteristics of various designs of existing acoustic screens are listed. A fundamentally new design of the acoustic screen is described: the panels have a ridge profi le, they are located along the vertical axis of the frame with a step at which the panels above the located ridge cover the top of the lower ridge, the outer surfaces of the panels and their end parts are made of a material that has sound-refl ecting properties, and the inner surfaces of the panels are made of sound-absorbing material. Such an acoustic screen is devoid of the disadvantages inherent in acoustic screens of other structures and is more effi cient. The considered invention allows due to the use of the ridge shape of acoustic panels: prevent the refl ection of sound energy in the direction of noise sources (a small part will be directed upwards); provide almost complete absorption of sound energy as it passes through the channels formed by the ridge panels; provide the same effective protection against noise sources located on both sides of the screen; prevent the formation of snow and ice crust on sound-absorbing surfaces, which ensures the constant eff ectiveness of the screen in diff erent seasons of the year; reduce metal consumption, which will reduce the weight of the structure without reducing its effi ciency and reduce the cost of acoustic screens.

CALCULATION OF ELECTROTHERMAL PROCESSES IN THE INDUCTION CHANNEL FURNACE IN THE STEADY-STATE OPERATION BASED ON THE THEORY OF THERMAL CIRCUITS

Based on the theory of thermal circuits, a computer model of an induction channel furnace has been developed, which is used to obtain industrial copper wire rods in the mode of continuous casting. The model allows calculating the established electrothermal processes considering the flows of cold and molten metal in its core. In the developed thermal model, it is proposed to consider the convection fluxes of heat in the metal using controlled current sources. The temperature distribution in the active zone of the channel furnace is calculated, and the influence of the mass flow of metal at the inlet and outlet of the furnace on the non-uniformity of temperature distribution in the active zone is shown. The obtained results allow determining the required electric power of the furnace at different values ​​of the flow rate of the metal that moves continuously through its core while heating to a given temperature. The developed model is relatively easy to implement, using the Matlab/Simulink package, and allows online to estimate the melt temperature in different zones depending on the electric power consumed by the furnace and the metal consumption at the outlet of the furnace, as well as to determine rational modes of its operation. Ref. 7, fig. 4.

Usage of Two-Sided Motors as a Part of the Simultaneous Separate Operation Technology

The technology of simultaneous, separate operation is a mandatory condition within the framework of Russian legislation for the production of oil and gas from multilayer reservoirs, which implies a share of a load of several pumps on different reservoirs. To reduce high additional equipment costs and metal consumption of the well, an assembly of two ESPs with one engine was developed. More than forty Russian wells were supplied with double ESP system motors. The project implementation enabled using separate simultaneous operations with more wells and developing reservoirs more accurately. It became possible to develop each reservoir by employing separated data from gauges connected to two reservoirs. The use of two side motors allows using such complicated technologies as separate simultaneous operations for even small and previously not economically achievable reservoirs. According to well inflow calculations, using the most suitable pump, the correct amount of liquid from each reservoir has been produced during these operations.

Slinging Unit For A Hollow-Core Floor Slab Of Stand-Off Formwork

Due to the fact that hollow-core slabs without formwork are produced without slinging loops (features of manufacturing technology), the issue of installation and transportation of these slabs has been solved. A constructive and technological solution is proposed for a slinging unit, arranged in the body of the slab, without the use of a slinging loop, and having only an anchor rod-dowel through which it is possible to directly sling the slab without using traditional slinging loops. The unit is designed with a reduced metal consumption and does not change the technology for manufacturing hollow-core slabs without formwork. Found and summed up a theoretical basis for calculating the bearing capacity of the proposed slinging unit, arranged in a hollow-core slab without formwork. It was revealed that the bearing capacity of the proposed slinging assembly, arranged in the body of a hollow-core slab, under the action of assembly loads, depends on the force of splitting the concrete of the protective layer located above the anchor rod-dowel of this assembly (all other things being equal). The theoretical data of the study were verified by full-scale tests of plates with slinging units arranged in their body, carried out in accordance with the proposed constructive and technological development. A utility model patent was obtained for the development of a loopless slinging unit for a hollow-core slab without formwork.

Optimization of the design of the pig launcher-receiver chambers of cleaning and diagnostic tools

По результатам проведенного анализа конструктивных решений камер пуска-приема средств очистки и диагностики (КПП СОД), применяемых при технической диагностике и техническом обслуживании магистральных трубопроводов в России и за рубежом, был установлен ряд проблем существующих конструкций, снижающих эксплуатационную надежность данного вида оборудования. Это, в свою очередь, обусловило актуальность задачи оптимизации конструкции КПП СОД, в том числе в части унификации используемых при их изготовлении деталей, увеличения доли заводских изделий. Были приняты решения, обеспечившие комплексный подход к вопросу повышения надежности и ремонтопригодности оборудования - разработана новая конструкция КПП СОД, позволяющая снизить металлоемкость и трудоемкость при изготовлении, сократить эксплуатационные затраты, повысить технологичность и прочностные характеристики. В рамках решения данной задачи выполнены расчетно-теоретические исследования с применением прикладного программного комплекса SIMULIA Abaqus. Надежность оптимизированной конструкции подтверждена результатами испытаний на прочность опытного образца КПП СОД с номинальным диаметром рабочей камеры DN 1000. Разработан типоразмерный ряд КПП СОД усовершенствованной конструкции с номинальными диаметрами рабочей камеры DN 150-1200 для применения на магистральных нефте- и нефтепродуктопроводах. Based on the results of the analysis of the design solutions of launching and receiver stations of pipeline inspection gauges (pig launchers-receivers) used in process diagnostics and maintenance of main pipelines in Russia and abroad, a number of applied design issues was established. This, in turn, led to the relevance of the issue of optimizing the design of pig launchers and receivers, including the unification of parts used in their manufacture, thereby increasing the share of factory-made products. Decisions were made that provided a comprehensive approach to the issue of improving the operational reliability of this type of equipment - a new design of pig launchers and receivers was developed, which allows to reduce production metal consumption and labor intensity, reduce operating costs, increase constructability and reliability. As part of the solution of this issue, computational and theoretical studies using the SIMULIA Abacus software package were carried out. The reliability of the optimized design is confirmed by the results of durability tests of the pig launcher and receiver prototype with the nominal diameter of the working chamber of DN 1000. A dimension range of advanced designs of pig launchers and receivers with nominal working chamber diameters of DN 150-1200 for use in main oil and petroleum product pipelines was developed.

Substantiation of probabilistic safety factors as a factor for optimizing the metal consumption of pipelines and the permissible operating pressure

Проведен анализ влияния коэффициентов вариации сопротивления материала разрушению и коэффициентов вариации нагрузки на вероятность разрушения и, следовательно, на коэффициенты запаса по характеристикам сопротивления материала разрушению при заданных показателях вероятности разрушения. Снижение неопределенности в условиях нагружения и повышение качества материала позволяют снизить коэффициенты запаса по пределу текучести и вязкости разрушения для заданных целевых показателей безопасности. На примере трубных сталей марок Ст 20 и 16ГС показана возможность снижения коэффициента запаса по пределу текучести до значений n = 1,45 при коэффициенте вариации нагрузки 0,1 и сохранении целевого показателя безопасности в терминах вероятности разрушения на уровне 10. Возможность снижения коэффициентов запаса по пределу текучести и вязкости разрушения при заданных целевых показателях безопасности в терминах вероятности разрушения позволяет оптимизировать металлоемкость и максимальные допустимые давления в эксплуатируемых трубопроводах. The analysis of the influence of the coefficients of variation of the material resistance and the coefficients of the load variation on the probability of failure as well as on the safety factors for the characteristics of the material resistance to failure has been done at given indicators of the probability of failure. Reducing uncertainty under loading conditions and improving material quality allow reducing the safety factors against fracture and collapse for given targets safety. Using the example of pipe steels of grades St 20 and 16GS, it seems possible to reduce the safety factor against collapse up to 1.45 with a load variation coefficient of 0.1 and maintaining the safety target in terms of the fracture probability at the level of 10. The possibility of reducing the safety factors against collapse and fracture at the given target safety indicators in terms of the fracture probability allows optimizing the metal consumption and the maximum allowable pressures in the operating pipelines.