Impact study of the distribution of cemented carbide on reinforced surfaces of samples of the crown bits of the rock drilling bits on the nature of their wear

В процесі буріння шарошковими долотами внаслідок зношування та затуплення породоруйнівних елементів має місце суттєве падіння механічної швидкості буріння. Для підвищення стійкості вінцевих зубків шарошкових доліт типів М і С одну з твірних поверхонь наплавляють твердим сплавом реліту з допомогою струмів високої частоти або газополуменевим методом. При зношуванні в процесі руйнування породи таких зубків на певну величину внаслідок оголення незміцненої серцевини зубка, зношування останньої проходить інтенсивніше за зовнішню армовану та зміцнену поверхню, що призводить до збільшення площі, яка контактує з поверхнею вибою. В процесі проведених досліджень впливу розміщення армуючого твердого сплаву на наплавлених поверхнях встановлено, що раціональним розміщенням твердого сплаву на наплавленій поверхні можна зберігати породоруйнівну здатність робочих елементів у процесі їхнього відпрацювання. Раціонально розміщуючи твердий сплав при наплавленні вінцевих зубків шарошок бурових доліт типів М і С, розміри поверхонь яких дозволяють це робити, економлячи при цьому недешевий твердий сплав, можна суттєво підвищувати ефективність буріння без додаткових енергетичних витрат.The paper deals with the study of the problem relating to the efficiency of the rock bit cutting structure work in the course of rock failure, which is associated with the rolling cutter teeth design peculiarities improvement. In the course of drilling with rock drilling bits, due to the wear and blunting of rock cutting elements, a significant drop in mechanical drilling speed occurs. To increase stability of the crown bits of rock drilling bits of M and C type, one of the forming surfaces is hard-faced with relit using high frequency currents or flame method. In the case of wear during rock failure of such bits for a certain amount as a result of exposure of unstable core of the bit, the wear of the latter occurs more intensely than of the reinforced external surface, which leads to an increase in the area that contacts the face surface. This paper gives the description of the study data obtained on the rock bit cutting structure durability in the form of milled investigated teeth while modeling their wear resistance conditions that are similar to the real ones. The effect of the working components of the rock bit cutting structure tools design peculiarities and their shape effect in the course of their wear on the rock failure are studied on the teeth penetration depth into the rock in particular. The degree of the initial rock failure characteristic of the patterns investigated was determined by the constant ability of their penetration depth into the elastic medium with the set physical and mechanical properties with the permanent axial loading by means of a specially developed device at the set period during their wear characteristics study. During the impact studies of the distribution of the reinforcing cemented carbide on flamed surfaces, it has been found that rational distribution of cemented carbide on flamed surface can preserve the rock cutting ability of working elements during their wear. Rational distribution of cemented carbide during the flaming of the crowned bits of drilling bits of M and C types, whose sizes of surfaces allow doing it, while saving expensive cemented carbide, can significantly increase drilling efficiency without additional energy costs. It has been confirmed that one of the efficient indices which can be characteristic both of the rock failure processes and those of possible wear and designing the rock failure tools appears to be the specific loading value transferred to the bottomhole while drilling

The stress state of compact mechatronic satellites of a cycloidal reducer

One of the urgent problems of mechanics is to design a lightweight, compact and precise reducer with high efficiency since it is an essential part of the robot actuators. The manufacture of modern toy robots made as Petmodels requires highly efficient and very compact drives. A topical part of the drive is the cycloidal reducer required to provide the torque appropriate for the effective movement of the toy. The article proposes a three-dimensional model of a cycloidal reducer designed for a four-legged walking robot toy. The outer diameter of the reducer is 56 mm. If its most significant parts are plastic, the weight does not exceed more than 0.2 kg. The obtained results of the analysis of stresses arising between the disk and the rollers indicate the complete suitability of the selected materials of polyamide and steel on their mechanical characteristics for use in the reducer of the robot actuator

Prediction of the accuracy of the tapered thread profile

The efficiency of drill string largely depends on the pipe-end connector’s accuracy named tapered thread tool joint. Most of those are made by using lathes. Turning tools were made with a profile identical to the thread profile, and all well-known world brands’ plants make the back rake angle of such a cutter with zero value. This is obviously due to the lack of a precise algorithm for calculating the cutter profile and ensuring the accuracy of the tapered thread profile. A virtual experiment was carried out of three-dimensional modeling of the process for shape creation. It showed that in the case of lathe machining of the thread of NC23 type, the deviation from the nominal half profile of the obtained thread is only 0.02°. This result prompted the decision to propose a new algorithm for predictive calculation of the half-angle of the cut profile based on the parameter associated with actual turning – the working height of the profile – h in contrast to previous scientific sources where this calculation was based on the parameter H – not truncated thread Height which is associated with the theoretical base of the accuracy of the thread. The result of the program application, created based on the algorithm proposed in the article, showed that the predicted accuracy of the obtained profile’s half-angle could be in a range from –0.03° to +0.10°, which is equivalent to 4–13 % of tolerance of this dimension

Synthesis, Biological Evaluation and Molecular Docking Studies of Novel Series of Bis-1,2,4-Triazoles as Thymidine Phosphorylase Inhibitor

Nataliya Korol,1 Oksana M Holovko-Kamoshenkova,1 Mikhailo Slivka,1 Oleksandra Pallah,2 Mykhailo Yu Onysko,1 Andriy Kryvovyaz,1 Nadiya V Boyko,2 Olha V Yaremko,3 Ruslan Mariychuk4 1Organic Chemistry Department, Educational and Research Institute of Chemistry and Ecology, Uzhhorod National University, Uzhhorod, Ukraine; 2Department of Clinical and Laboratory Diagnostics and Pharmacology, Faculty of Dentistry, Uzhhorod National University, Uzhhorod, Ukraine; 3Department of Microbiology and Virology, Lviv National Stepan Gzhytsky University of Veterinary Medicine and Biotechnology, Lviv, Ukraine; 4Department of Ecology, Faculty of Humanities and Natural Science, University of Presov, Presov, Slovak RepublicCorrespondence: Nataliya Korol, Organic Chemistry Department, Educational and Research Institute of Chemistry and Ecology, Uzhhorod National University, Tomchaniia Street, 13, Uzhhorod, 88001, Ukraine, Tel +380 95 704 34 56, Email [email protected]: Heterocyclic compounds have diverse biological activities and potential in drug development. This study aims to synthesize novel compounds with two 1,2,4-triazole cores and evaluate their biological properties, particularly their inhibitory activity against thymidine phosphorylase (TP), an enzyme involved in various physiological processes.Methods: The compounds were synthesized by reacting 5,5’-butane-bis-1,2,4-triazole derivatives with prenyl bromide. Characterization involved various techniques, including spectroscopy and elemental analysis. Antimicrobial potential was evaluated against bacteria and fungi, with comparative antibiotics as references. Inhibitory activity against TP was assessed, and molecular docking studies were conducted.Results: Six compounds were successfully synthesized and their structures confirmed. The synthesized triazole derivatives exhibited high biological activity, with compounds 2 and 6 showing the most promising TP inhibition. Molecular docking studies revealed interactions between compound 2 and TP, involving nine amino acids.Discussion: The synthesis of novel compounds with two 1,2,4-triazole cores contributes significantly to bis-triazole research. These compounds have potential as anti-tumor agents due to their inhibitory activity against TP, a crucial enzyme in tumor growth and metastasis. Comparative evaluation against antibiotics highlights their potency. Docking results provide insights into their interactions with TP, supporting their potential as potent TP inhibitors. Further research should focus on evaluating their efficacy in biological models, understanding their mechanisms of action, and optimizing their activities.Conclusion: The synthesized compounds with two 1,2,4-triazole cores exhibit significant biological activity, including strong TP inhibition and broad-spectrum antimicrobial effects. These findings emphasize their potential as anti-tumor agents and the need for further exploration and optimization. Future research should focus on evaluating their efficacy in biological models, understanding their mechanisms of action, and developing more potent bis-triazole derivatives for drug discovery efforts. The combined results from assays and docking studies support the therapeutic potential of these compounds as anti-tumor agents.Keywords: alkylations, antitumor agents, heterocycles, hydrogen bonds, molecular modellin

Z,E-Isomerism in a Series of Substituted Iminophosphonates: Quantum Chemical Research

Esters of iminophosphonic acids (iminophosphonates, or IPs), including a fragment, >P(=O)-C=N, can be easily functionalized, for instance to aminophosphonic acids with a wide range of biological activity. Depending on the character of the substitution, the Z- or E-configuration is favorable for IPs, which in turn can influence the stereochemistry of the products of chemical transformations of IPs. While the Z,E-isomerism in IPs has been thoroughly studied by NMR spectroscopy, the factors stabilizing a definite isomer are still not clear. In the current work, density functional theory (DFT, using M06-2X functional) and ab initio spin-component–scaled second-order Møller–Plesset perturbation theory (SCS-MP2) calculations were carried out for a broad series of IPs. The calculations reproduce well a subtle balance between the preferred Z-configuration inherent for C-trifluoromethyl substituted IPs and the E-form, which is more stable for C-alkyl- or aryl-substituted IPs. The predicted trend of changing activation energy values agrees well with the recently determined experimental ΔG≠298 magnitudes. Depending on the substitution in the aromatic moiety, the Z/E-isomerization of N-aryl-substituted IPs proceeds via two types of close-in energy transition states. Not a single main factor but a combination of various contributions should be considered in order to explain the Z/E-isomerization equilibrium for different IPs