RESEARCH OF THERMAL STATUS OF THREADING ZONE WITH THE HELP OF FULL FACTOR EXPERIMENT

Thermal processing zone status when threading in heatproof, high-strength and titanium alloys is a major problem in the general theory of metal cutting. Under other equal conditions temperature in the processing zone of these materials is higher than in cutting of carbon structural steels, as they have high strength and ductility, low thermal conductivity, that makes difficult the working conditions of the taps, increases the area of the tool contact with the workpiece, deteriorates lubrication and cooling of the cutting area because of the increased tendency of heatresistant materials for the curing. This causes an increase in the work and force of friction and as a consequence the rise of cutting temperature. Research of temperature state of the threaded coils formation zone with combined countersink tool-tap is one of the major challenges facing the authors of this work. When performing the work was used factorial experiment. The temperature in the cutting zone of the thread was determined by a built-in chromel-aluminum thermocouple with thermoelectrode cross-sectional area 0,23mm2 . Experiments were carried out using the apparatus of mathematical statistics. Studies have shown that the greatest impact on the temperature state of the cutting area has a tensile strength of the material. Effect of cutting speed in the studied variation range is relatively less noticeable. The explanation for this is a special scheme of cutting of combined countersink tap which allows significantly improve conditions in the cutting zone. The proposed design of the tap allows to reduce the temperature in the area of tapping for 20%

EXPLANATION END DEVELOPMENT OF COMBINED TOOL CORE DRILL TAP WITH THE NEW CUTTING SCHEME

The results of the research on thread making in hard-to-machine materials are given. A new technology with use of combined core drill tap allowing the stabilization of the stock for further processing, correction of the hole axis and provision of larger severity of the tool is developed. The factors influencing on the quality and performance of thread making reliability and working capacity of the tap cutting tool are identified. The recommendations on tool friction and heating reduce in order to provide the larger severity and durability are given

THE TECHNOLOGY OF INTERNAL THREAD CUTTING OF HIGH PRECISION IN PARTS OF SHIP MACHINE COMPONENTS, MACHINERY AND SHIP ARMATURE

Abstract. Conducted laboratory studies of the threading in the details of ship machinery and ship armatures from hard materials helped to create the modern technology of internal threads of small diameters cutting. The reasons that impede the processing of hard materials are find out.Presented are various designs of taps for cutting of internal threads and analyzed is their work. Noted are shortcomings of their designs resulting in creating a modern cutting pattern, allowing to minimize the shortages identified in the processing of hard materials. Practice shows that the machining of these materials is difficult because of their considerable tendency to work hardening during deformation, high viscosity, poor heat dissipation from the cutting zone.They have a low coefficient of thermal conductivity and low coefficient of workability relatively to tool steel. Therefore, processing technology and cutting conditions used for structural carbon steels, often are unacceptable to hard materials.The most difficult is tapping into the holes of small diameters up to 16 mm. The disadvantage of this technology is the low quality of threaded surfaces and an increased tendency to tap breakage. To improve threading performance in the details of the hard materials are developed advanced threading techniques

STUDY AND OPTIMIZATION OF EFFICIENCY AND DURABILITY COMBINED TOOL CORE DRILL-TAP

The integrated studies identified factors influencing wear resistance of tapping and part of the combined tool, which has been studied and optimized its kinetics. The influence of tool wear on geometrical figures thead, performance, torque. The main factors influencing the performance of processing threads. As a result of the study, it was found that the main factors are the cutting speed (V) limit the temporary v resistance of the material to be processed and the reverse cone angle δ. In order to optimize these parameters a full-factorial experiment. On the basis of the received data was built a graphical model of the optimum, which allows you to define basic settings for processing (V, φ), depending on the ultimate strength of the material and shows the kind of stability and performance of the tool

METHODS OF CONTROLLING THE AVERAGE DIAMETER OF THE THREAD WITH ASYMMETRICAL PROFILE

To handle the threaded holes in hard materials made of marine machinery, operating at high temperatures, heavy loads and in aggressive environments, the authors have developed the combined tool core drill -tap with a special cutting scheme, which has an asymmetric thread profile on the tap part. In order to control the average diameter of the thread of tap part of the combined tool was used the method three wires, which allows to make continuous measurement of the average diameter of the thread along the entire profile. Deviation from the average diameter from the sample is registered by inductive sensor and is recorded by the recorder. In the work are developed and presented control schemes of the average diameter of the threads with a symmetrical and asymmetrical profile. On the basis of these schemes are derived formulas for calculating the theoretical option to set the wires in the thread profile in the process of measuring the average diameter. Conducted complex research and the introduction of the combined instrument core drill-tap in the production of products of marine engineering, shipbuilding, ship repair power plants made of hard materials showed a high efficiency of the proposed technology for the processing of high-quality small-diameter threaded holes that meet modern requirements

Derbend-Nameh by Muhammad Avabi Aktashi: A Literary Reflection of Khazar History and How the City of Anji Was Destructed

Introduction. The paper attempts a scholarly insight into medieval historical chronicles for a new comprehension of Derbend-Nameh by Muhammad Avabi Aktashi (sixteenth–seventeenth centuries) that stands at the beginnings of Dagestani prose. Goals. The study seeks to identify the literary task set forth by the medieval author when he set to create the historical/literary narrative, reveal some meanings hidden therein, and show how the author influences a reader with the aid of stylistic techniques and expressive means. Methods. The work employs the cultural/historical and receptive methods, the latter be manifested (implemented) via ‘readers’ expectations’, certain derived genre norms, implied correlations between fiction and reality, text and context. The hermeneutic method proves most instrumental in revealing opportunities for multiple interpretations of one and the same text. Results. Our study attest to the author used not only documents and facts from the preceding Tawarikh-i Derbend-Nameh (The Book of Derbent Stories) but also invested his own knowledge of ancient fiction and undertones — to establish the genre of historical prose in Kumyk literature. This is evidenced by the author’s appeal to the key characteristic features of fiction: abundance of folklore legends, fragments from Arab, Oriental and European chronicles and fiction texts; hyperbolized narration about the size of Derbent and the Derbent Wall; fantastic elements, images of historical personalities, such as Zulkarnein Iskander (Alexander the Great), Kubad-Shah, Abu-Muslim and others; the formal and compositional division of the text (war between Arabs and Khazars, war between Persians and Khazars, ruling years of Abu Muslim); hidden meanings of the narrative about Khazars and the city of Anji (emotional narrative of battles attended by Khazars and Muslims); reflections on the turning point in history, impacts on the reader’s feelings by means of literary devices and artistic expressions. Conclusions. Despite the book by Muhammad Avabi Aktashi deals with the history of Derbent, it clearly shows the author’s intention and literary task to shed light on another city, the ancient Anji, as well as on the tragic collapse of the Khazar state. It is shown that the book served a landmark at the beginnings of Kumyk prose — and gave impulse to the latter’s further evolution

Paracrine mechanisms of antiinflammatory and organoprotective effects in MSC transplantation

The purpose of this review was to systematize data of many studies and observations of paracrine factors of MSC and their biological effects. Also a brief description of main groups of cytokins was revealed in the review

Low-molecular peptide preparations obtained from cultivated stem cells in the treatment of acute renal failure

Data on the efficiency of low-molecular peptide preparations, selected from cultivated stem cells of marrow, in the treatment of acute kidney insufficiency in experimental animals are resulted. It is demonstrated that the use of peptide preparations reliably promotes survivability of experimental animals suffering from acute kidney insufficiency