Surface Hardening Technology with a Concentrated Energy Source

The article is devoted to the increase of wear resistance of large-modular gears due to the application of the innovative method of plasma surface hardening working surfaces of teeth. The method of determination and estimation of the residual resource of large-modular gear transmissions after plasma surface hardening is developed and the influence of technological parameters of this process on wear resistance and mechanisms of deterioration of the surface layer have been investigated. The process of plasma surface hardening has been experimentally investigated, an estimation of the obtained physical and mechanical properties and hardness of the processed material during plasma heating has been made. The increase of durability of the work of large-modular gears passing by the plasma surface hardening has been experimentally investigated and the calculations on durability have been performed for the wear parameter, and it has been established that the application of this heat treatment method increases the durability 2.28 times. A complex of specialized equipment was developed for the implementation of the technological scheme of plasma surface hardening of the large-modular gears' working surfaces without melting, using the original design of the magnetic-deflection system for the creation of an external magnetic field

Multi-scale magnetic field structures in an expanding elongated plasma cloud with hot electrons subject to an external magnetic field

We carry out 3D and 2D PIC-simulations of the expansion of a magnetized plasma that initially uniformly fills a half-space and contains a semi-cylindrical region of heated electrons elongated along the surface of the plasma boundary. This geometry is related, for instance, to the ablation of a plane target by a femtosecond laser beam under quasi-cylindrical focusing. We find that the decay of the inhomogeneous plasma--vacuum discontinuity is strongly affected by an external magnetic field parallel to its boundary. We observe various transient phenomena, including the anisotropic scattering of electrons and the accompanying Weibel instability, and reveal various spatial structures of the arising magnetic field and current, including multiple flying apart filaments of a z-pinch type and slowly evolving current sheets with different orientations. The magnitude of the self-generated magnetic field can be of the order of or significantly exceed that of the external one. Such phenomena are expected in the laser and cosmic plasmas, including the explosive processes in the planetary magnetospheres and stellar coronal arches.Comment: 13 pages, 6 figures, submitted to JP

The Effect of Pristine and Pegylated Graphene Oxide Nanosheets on the Functions of Human Neutrophils

Graphene oxide (GO) is very useful for biomedicine, due to its physicochemical properties; therefore, its interaction with cells of the immune system has beenextensively studied. Many studies have aimed toreduce the undesirable effects of GO through chemical modification, including through polyethylene glycol (PEG) coating. Neutrophils are the first to respond to foreign object invasion in the body. Their main functions are the uptake and destruction of foreign particles, including with the help of reactive oxygen species (ROS).Our study aimed to investigate theengulfment of unmodified graphene oxide (GO) and graphene oxide coated with polyethylene glycol (GO-PEG) by human neutrophils and the effect of nanosheets on the production of ROS.We used sheets of GO (Ossila, Great Britain, average plate size 1-5 μm) and GO-PEG (569 ± 14 nm, PEG coating≈ 20%) at concentrations of 12.5μg/mL, 25μg/mL, and 50 μg/mL. The uptake of nanosheets was assessed by flow cytometry, taking into account the level of background adhesion of nanoparticles. ROS production was evaluated by luminol-dependent chemiluminescence (LCL).It was found that GO (12.5μg/mL, 25μg/mL, and 50 μg/mL) was actively internalized by neutrophils, while the uptake of GO-PEG was not detected. GO and GO-PEG particles (25 μg/mLand 50 μg/mL) reduced the total production of ROS by human leukocytes.Thus, the modifying of GOnanosheets with PEG resulted in the abolishment of their active uptake by neutrophils but did not affect the GO inhibitory effect on their oxidative activity. Keywords: graphene oxide surface modification, pegylated graphene oxide nanosheets, nanoparticle uptake, human neutrophils, of reactive oxygen specie

Daytime ozone loss term in the mesopause region

For the retrieval of atomic oxygen via ozone observations in the extended mesopause region under sunlight conditions, two assumptions are used: first, the photochemical equilibrium of ozone and, second, that the ozone losses are dominated by ozone's dissociation from solar UV radiation, silently ignoring the O3 destruction by atomic hydrogen. We verify both by 3-D modeling. We found that ozone approaches photochemical equilibrium at 75–100 km for daytime conditions. Hence, the first assumption is valid. However, the reaction of ozone with atomic hydrogen was found to be an important loss process and should not be omitted in retrieving atomic oxygen

Дослідження можливості плазмово-механічної обробки деталей обладнання для суднобудування

Нечаєв, В. П. Дослідження можливості плазмово-механічної обробки деталей обладнання для суднобудування = The study of possibility of plasma-assisted machining for shipbuilding equipment parts / В. П. Нечаєв, А. О. Рязанцев // Shipbuilding & Marine Infrastructure. – 2018. – № 2 (10). – С. 199–203.Анотація. Проаналізовано результати впливу плазмової дуги на матеріал припуску заготовок із важкооброблюваних матеріалів, обґрунтовано можливості підвищення продуктивності обробки на металорізальних верстатах, описано процес плазмово-механічної обробки (ПМО). Деталі сучасного обладнання для суднобудування виготовляють зі сталей і сплавів з підвищеними механічними характеристиками, що призводить до значних труднощів під час оброблення на металорізальних верстатах. Процес оброблення супроводжується підвищеним опором різанню, високими температурами в зоні оброблення, швидкою втратою різальної здатності інструмента. Зниження негативного впливу названих факторів є можливим завдяки застосуванню високотемпературного плазмового нагрівання матеріалу зрізаного припуску. Нагрівання заготовки плазмовою дугою викликає низку явищ: збільшення здатності оброблюваного металу до пластичної деформації, зниження його міцності, виникнення системи структурних перетворень і термічних напружень у поверхневих шарах заготовки, розплавлювання поверхневого шару припуску, зміна параметрів тертя на контактних поверхнях заготовки й інструмента, температури контакту, зміна хімічного складу в поверхневих шарах. Технічний результат від використання пропонованої моделі ПМО литих і кованих злитків та заготовок із твердою ливарною кіркою або важкооброблюваних сплавів забезпечує поліпшення оброблюваності шляхом створення по всьому перетину припуску за рахунок термічного впливу, аустенітної або іншої структури, яка має значно нижчі фізико-механічні властивості, ніж вихідний матеріал заготовки. Унаслідок цього також підвищується період стійкості різального інструменту. У реальних виробничих умовах необхідно дотримуватися вимог до джерела високотемпературного плазмового нагрівання: можливість регулювання розмірів зони нагрівання, відсутність оплавлення поверхневого шару, забезпечення рівномірної глибини структурних перетворень, досягнення раціональної мікроструктури зміцненого шару. Застосування технології ПМО забезпечує підвищення продуктивності обробки заготовок з важкооброблюваних матеріалів, які використовуються в суднобудуванні, енергетичному й гірничому машинобудуванні.Abstract. In this article, an analysis of the results of the plasma arc effect on the material of the stock of hard-to-machine materials was conducted and to substantiate the possibility of increasing the productivity of their treatment on metal-cutting machine tools, and a method for implementing the plasma-assisted machining (PAM) process was described. Details of modern equipment for shipbuilding are made of steels and alloys with increased mechanical characteristics, which lead to considerable difficulties in their processing on metal-cutting machines. The processing process is accompanied by increased resistance to cutting, high temperatures in the treatment area, rapid loss of cutting power of the tool. Reducing the negative effects of these factors is possible due to the application of high-temperature plasma heating of the allowance material. The heating of the work piece with a plasma arc causes a number of phenomena: an increase in the ability of the treated metal to plastic deformation; reducing its strength; the emergence of a system of structural transformations and thermal stresses in the surface layers of the work piece; melting of the superficial layer of allowance; change of friction parameters on contact surfaces of a work piece and tool, contact temperature; change in the chemical composition in the surface layers. The technical result from the use of the proposed model of plasma-assisted machining of cast and forged ingots and work pieces with solid casting crust, or from hard-working alloys, provides an improvement in their machining through the creation of an entire inlet section, due to thermal influences, austenitic or other structure that is significantly lower physical and mechanical properties, than the source material of the work piece. As a result, the period of stability of the cutting tool also increases. In real production conditions, it is necessary to comply with the requirements for a source of high-temperature plasma heating: the ability to control the size of the heating zone; no melting of the surface layer; ensuring uniform depth of structural transformations; achieving a rational microstructure of the hardened layer. The use of technology of plasmaassisted machining provides an increase in the productivity of processing work pieces from hard-to-machine materials that are used in shipbuilding, power and mining engineering.Аннотация. Проанализированы результаты воздействия плазменной дуги на материал припуска заготовок из труднообрабатываемых материалов, обоснованы возможности повышения производительности обработки на металлорежущих станках, описан процесс плазменно-механической обработки (ПМО). Детали современного оборудования для судостроения изготавливают из сталей и сплавов с повышенными механическими характеристиками, что приводит к значительным трудностям при обработке на металлорежущих станках. Процесс обработки сопровождается повышенным сопротивлением резке, высокими температурами в зоне обработки, быстрой потерей режущей способности инструмента. Снижение негативного воздействия названных факторов возможно благодаря применению высокотемпературного плазменного нагрева материала срезанного припуска. Нагрев заготовки плазменной дугой вызывает ряд явлений: увеличение способности обрабатываемого металла к пластической деформации, снижение его прочности, возникновение системы структурных преобразований и термических напряжений в поверхностных слоях заготовки, расплавление поверхностного слоя припуска, изменение параметров трения на контактных поверхностях заготовки и инструмента, температуры контакта, изменение химического состава в поверхностных слоях. Технический результат от использования предлагаемой модели ПМО литых и кованых слитков и заготовок из твердой литейной корки или труднообрабатываемых сплавов обеспечивает улучшение обрабатываемости путем создания по всему сечению припуска за счет термического воздействия, аустенитной или другой структуры, которая имеет значительно худшие физико-механические свойства, чем исходный материал заготовки. В результате также повышается период стойкости режущего инструмента. В реальных производственных условиях необходимо соблюдать требования к источнику высокотемпературного плазменного нагрева: возможность регулирования размеров зоны нагрева, отсутствие оплавления поверхностного слоя, обеспечение равномерной глубины структурных преобразований, достижение рациональной микроструктуры укрепленного слоя. Применение технологии ПМО обеспечивает повышение производительности обработки заготовок из труднообрабатываемых материалов, используемых в судостроении, энергетическом и горном машиностроении

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

Diversity-Oriented Synthesis of Heterocycles through Post-MCR Functionalization of the Triple Bond

status: publishe

The Application of Multicomponent Ugi and Passerini Reactions for the One-Pot Synthesis of Pyrrolones and Butenolides

A new protocol for the one-pot synthesis of pyrrolones and butenolides involving an isocyanide-based multicomponent reaction (Ugi or Passerini) followed by a triethylamine-promoted cycloisomerization is described.status: publishe

ADAPTATION OF SOFTWARE SYSTEMS TO USER TASKS BASED ON THE METHOD OF CONFIGURATION MODELING

In this paper, we discuss task of adaptation of software systems (PCs) and complexes (PCs) on the basis of the configuration modeling (MCM) method is considered. The article describes designated purpose of MCM in the field of SSs development, describes background and justification for the development of adap- tive SSs, and many of the advantages of creating configurable SSs. The main attention is paid to the analysis and research of the software engineering and implementation of adaptive SSs using the configuration mechanism as a mean of adapting SSs to the problem of interest. The potential for using configuration modeling in this area is determined. The meaning of the concepts «configurator», «configuration» and «reconfiguration» in the context of the description of MCM implementation of adaptive SSs creation is considered. The article gives a real example of an adaptive SS describing MCMs application in the process of software engineering. A conceptual model of such a SS is described, and its interpretation is implement- ed in the form of a modular complex data processing system (CDPS). The example of the CDPS shows the structural scheme of the conceptual model of the data handling process, decomposes the CDPS into the basic modules, including the built-in configuration module. Special attention to a detailed description of the problem of interest and the functionality of each module is paid, as well as to the description of the relationships between them. On the basis of the CDPS, the solution of the problem of adapting PSs with the elements of dynamic configuration based on the input data is realized. The example of the CDPS describes user-accessible operating modes of the SS corresponding to various system configurations determined according to the tasks to be solved. The article makes it possible to obtain an abstract presentation on the methods and principles for the creation of adaptive SS. Moreover, a concrete understanding of the imple- mentation of adaptation by using the configuration management mechanism is covered. Additionally, the article highlights direct benefits and potential profit from using of configurator in software engineering