Влияние горячей пластической деформации на морфологию графита и металлическую матрицу высокопрочного чугуна

The results of studies showing the effects of hot plastic deformation on the processes of forming graphite inclusions and hardening of metal matrix are presented. Found that with increasing degree of hot plastic deformation, not only the shape of graphite inclusions changes, but their redistribution in the plane of the section changes also, which affects the anisotropy properties of nodular iron. Based on these results a conclusion is made that with the help of hot plastic deformation it is possible to obtain the specified strength characteristics of ductile iron.Описаны результаты исследования влияния горячей пластической деформации на процессы формоизменения включений графита и упрочнения металлической матрицы. Показано, что с увеличением значения горячей пластической деформации происходят не только изменение формы включений графита, но и перераспределение их в плоскости шлифа, что влияет на анизотропию свойств материала. Полученные результаты могут быть использованы для повышения прочностных характеристик различных машиностроительных деталей

DETERMINATION OF OPTIMIZATION WAYS OF RE-PROTHESIS USING VARIOUS SCHEMES GNATHOLOGICAL SUPPORT OF PATIENTS AT THE PREPARATORY STAGE TO THE ORTHOPEDIC CORRECTION OF PATIENTS WITH OCCLUSIVE IATROGENIC DISORDERS OF TOOTH-JAW APPARATUS

We brought to the light that one of the the most controversial issues is the moment of adaptation to reconstructive procedures. Often it becomes unclear which and in which order to use medical diagnostic equipment, to training for fixed prosthetic stages. Our studies make it possible to predict not only the treatment time, but the amount of occlusal adjustment in conjunction with the reconstruction of the position of the mandible.One of the most debated issues is the time of adaptation to reconstructive manipulation. Often it becomes unclear how and in what order medical diagnostic equipment should be used in the preparatory stages of the stationary prosthetics. Our studies make it possible to predict not only the treatment time, and the amount of occlusal adjustment in conjunction with the reconstruction of the lower jaw. Keywords: tooth-jaw apparatus, temporomandibular joint, violation functional occlusion, dental surgery, medical diagnostic devices, muscle disorders, adaptation, occlusal splint, occlusal adjustment, chewing muscles, provisional design

Оценка прочностных характеристик полимерных материалов для изготовления элементов персонального электротранспорта

The properties of materials for airless wheel propulsion of vehicles, including electric ones, have been studied. The experimental substantiation of the choice of the type of polymer matrices and compositions of reinforcing fillers for the manufacture of an airless wheel mover of electric vehicles has been carried out. To test the basic epoxy matrix, part of the samples without the addition of reinforcing fibers was cured at room temperature (L-285H), and the rest (L-285G) – when heated to 60 °C. In order to improve the strength characteristics of the epoxy matrix L-285G, glass reinforcement was carried out with EC16 1600T-16(400) glass reinforcement. The Smooth-Cast 300 Series was chosen as the matrix for performing samples based on injection-molded polyurethanes. Samples are made of base polyurethane under various conditions: at atmospheric rejection (SC), under vacuum 0.8 kPa (SC-0.8) and during vibration-induced curing (SCV). Comparative tests were carried out, which showed differences in the mechanical properties of the base matrices based on epoxy resins and injection-molded polyurethanes, in particular, the relative elongation of samples from injection-molded polyurethane by more than 2 times. It is established that the most rational use of injection-molded polyurethane is application as damping elements, and the material for manufacturing spokes dampers is composite SCV-S-20. It is advisable to manufacture products from the resulting composite when vibrations are applied to the mold and with preliminary vacuuming at a vacuum of 0.8 kPa of the components of the polyurethane matrix, which reduces the number of internal defects in the form of shells. Since vacuuming of the product during polymerization does not give a significant effect due to the presence of a set of specialized deaeration additives in the base matrix, it is proposed to carry it out under constant control, since exceeding the vacuum in the range from 0.8 to 0.9 kPa entails decomposition of individual matrix components with foam formation.Изучены свойства материалов для безвоздушного колесного движителя транспортных средств, в том числе электрических. Выполнено экспериментальное обоснование выбора типа полимерных матриц и составов армирующих наполнителей для изготовления безвоздушного колесного движителя электротранспортных средств. Для проведения испытаний базовой эпоксидной матрицы часть образцов без добавления армирующих волокон отверждалась при комнатной температуре (L-285H), а остальные (L-285G) – при нагреве до 60 °С. В целях улучшения прочностных характеристик эпоксидной матрицы L-285G проводили армирование стеклоровингом ЕС16 1600Т-16(400). Матрицей для выполнения образцов на базе литьевых полиуретанов был выбран Smooth-Cast 300 Series. Из базового полиуретана изготовлены образцы при различных условиях: при атмосферном отвержении (SC), под вакуумом –81,1 кПа (SC-0.8) и при отверждении с наложением вибрации (SCV). Проведены сравнительные испытания, которые показали отличия механических свойств базовых матриц на базе эпоксидных смол и литьевых полиуретанов, в частности относительное удлинение образцов из литьевого полиуретана более чем в 2 раза. Установлено, что в качестве демпфирующих элементов наиболее рационально применение литьевого полиуретана, а материала изготовления спиц-демпферов – композита SCV-S-20. Изготовление изделий из полученного композита целесообразно проводить при наложении на форму вибраций и с предварительным вакуумированием при вакууме 81,1 кПа компонентов полиуретановой матрицы, что позволяет снизить количество внутренних дефектов в виде раковин. Вакуумирование изделия при полимеризации не дает значимого эффекта ввиду наличия в базовой матрице комплекта специализированных деаэрационных присадок, поэтому предложено проводить его при постоянном контроле, так как превышение вакуума в пределах от 81,1 до 91,2 кПа влечет разложение отдельных компонентов матрицы с образованием пены

ANALYSIS OF THE DYNAMICS OF CHANGING THE INDICATORS OF THE FUNCTIONAL OCCLUSION ASSESSMENT METHOD T-SCAN IN PATIENTS WITH OCCLUSION DISORDERS WHICH HAVE BEEN ARISEN OR WERE ACTIVATED AS A RESULT OF INCORRECT DENTAL SURGERY

Recent studies showed that regaining the occlusal contacts is one of the most difficult tasks during the prosthetics remanufacturing process. It often happens, that during prosthetics remanufacturing process misunderstanding between a patient and a doctor may occur. It is related to the removal of expensive structures and manufacturing of new ones that are just as pricey. Thus, the touchstone for achieving optimal functional and esthetic results is not only the repositioning of the mandible that eliminates pain sensation in TMJ, but also regaining of the occlusal contacts is needed for prosthetics remanufacturing. Thereby, by knowing the treatment outcome, the doctor is able to minimize the risk of error in prosthetics re-manufacturing process and improve the doctor-patient relationship.Key words: maxillo-dental apparatus, temporomandibular joint, occlusive correction, masticatory muscles, pharmaceutical construction

Применение вибродиагностики при создании элементов персонального электротранспорта

The study of vibration loading of the main elements of personal electric vehicles and the search for ways to reduce vibration characteristics was conducted. The issues of measuring vibration arising on a bicycle, which is driven by human muscle power and an electric drive, are considered. Measurements of vibration acceleration and frequency spectra in a certain area of motion were carried out using the “Octave-101VM” spectrum analyzer in three stages. At the first stage, the electric bike was driven by a pedal drive, at the second – by an electric drive, at the third – the pedals and the electric drive worked in parallel. As a result of the tests carried out, it was found that the greatest vibration occurred in the “Motor” mode during the use of an electric bicycle, the least vibration occurred when driving with the electric motor turned off. It was found that the electric drive increases the vibration level (at the same time, the electric bike does not exceed the maximum permissible values of vibration levels on all axes). In order to reduce the vibration arising from the electric motor on a personal electric vehicle, a 3D computer model has been developed and an airless wheel mover has been manufactured using this model on a 3D printer (a wheel for an electric scooter with internal damping has been manufactured). Bench tests have shown that the developed wheel, in comparison with a pneumatic tire, has a smaller (up to 45 %) contact spot. The results obtained can be used in the development of competitive products, in particular personal electric vehicles.Проведено исследование вибронагруженности основных элементов персональных электрических транспортных средств и поиск путей снижения вибрационных характеристик. Рассмотрены вопросы измерения вибрации, возникающей на велосипеде, который приводится в движение мускульной силой человека и электроприводом. Измерения виброускорения и частотных спектров на определенном участке движения осуществлялись с помощью анализатора спектра «Октава-101ВМ» в три этапа. На первом этапе электровелосипед приводился в движение с помощью педального привода, на втором – электроприводом, на третьем – педали и электропривод работали параллельно. В результате проведенных испытаний установлено, что наибольшая вибрация происходила в режиме «Мотор» в процессе использования электровелосипеда, наименьшая вибрация – при езде с выключенным электродвигателем. Обнаружено, что электропривод увеличивает уровень вибрации (при этом у электровелосипеда по всем осям не происходит превышения предельно допустимых значений уровней вибраций). С целью уменьшения возникающей от электродвигателя вибрации на персональном электротранспорте разработана компьютерная 3D-модель и изготовлен по данной модели на 3D-принтере безвоздушный колесный движитель (колесо для электросамоката с внутренним демпфированием). Стендовые испытания показали, что разработанное колесо в сравнении с пневматической шиной имеет меньшее (до 45 %) пятно контакта. Полученные результаты можно использовать при разработке конкурентоспособной продукции, в частности персонального электротранспорта

Токопроводящие материалы для соединительных шин многоэлементных аккумуляторных тяговых батарей

The article deals with the choice of materials for connecting tires of traction batteries (TB). The optimal parameters of their spot welding with batteries are experimentally established (the first pulse with a current of 7 kA duration of 1 ms, the break between the pulses of 1 ms, the second pulse with a current of 7 kA duration of 2 ms). When operating the traction battery on electric vehicles, the resistance of the connecting tires should not lead to heating of the batteries in order to avoid overheating above 60 °C. In most modern TB, consisting of Li-ion elements, a nickel tape is used for the connection. To ensure the weldability of materials (copper–nickel or nickel–nickel), it is important that the operating temperature is reached at a short-term current pulse in the welding zone. One of the solutions to this problem is the application of a metal coating. Experiments were conducted on the weldability of various materials, including those with applied coatings. The best results in weldability were shown by tires made of tinned copper, which was welded to nickel plates (emitting the battery body). Tear tests of the welded samples were carried out. The tensile strength of the original copper tires was 340–450 MPa. When welding copper–nickel and copper(tinned) – nickel plates, the strength limit values reach 70 % of the strength of the original copper plate. On the basis of the obtained experimental data, a pilot batch of battery TB was manufactured, which successfully passed tests for compliance with the technical requirements for the strength and the value of the transition resistances of the welded joints of connecting buses with batteries.Рассмотрены вопросы выбора материалов для соединительных шин тяговых батарей (ТБ). Экспериментально установлены оптимальные параметры их точечной сварки с элементами питания: первый импульс с силой тока 7 кА длительностью 1 мс, перерыв между импульсами 1 мс, второй импульс с силой тока 7 кА длительностью 2 мс. При работе ТБ на электротранспорте сопротивление соединительных шин не должно приводить к нагреву элементов питания во избежание перегрева выше 60 °С. В большинстве современных ТБ, состоящих из литий-ионных элементов, для соединения используется никелевая лента. Для обеспечения свариваемости материалов (медь–никель или никель–никель) важно, чтобы при краткосрочном импульсе тока в зоне сварки была достигнута рабочая температура. Один из вариантов решения данной задачи – это нанесение металлического покрытия. Проведены эксперименты по свариваемости различных материалов, в том числе с нанесенными покрытиями. Наилучшие результаты по свариваемости показала шина из луженой меди, которую приваривали к никелевым пластинам, эмитирующим корпус элемента питания. Проведены испытания на разрыв сваренных образцов. Предел прочности на разрыв исходных шин меди составил 340–450 МПа. При сваривании пластин медь–никель и медь (луженая) – никель показатели предела прочности достигли 70 % от прочности исходной медной пластины. На основании полученных экспериментальных данных изготовлена опытная партия аккумуляторных ТБ, которая успешно прошла испытания на соответствие техническим требованиям по прочности и величине переходных сопротивлений сварных соединений соединительных шин с элементами питания

The atmospheric role in the Arctic water cycle: A review on processes, past and future changes, and their impacts

This is the final version of the article. Available from the publisher via the DOI in this record.Atmospheric humidity, clouds, precipitation, and evapotranspiration are essential components of the Arctic climate system. During recent decades, specific humidity and precipitation have generally increased in the Arctic, but changes in evapotranspiration are poorly known. Trends in clouds vary depending on the region and season. Climate model experiments suggest that increases in precipitation are related to global warming. In turn, feedbacks associated with the increase in atmospheric moisture and decrease in sea ice and snow cover have contributed to the Arctic amplification of global warming. Climate models have captured the overall wetting trend but have limited success in reproducing regional details. For the rest of the 21st century, climate models project strong warming and increasing precipitation, but different models yield different results for changes in cloud cover. The model differences are largest in months of minimum sea ice cover. Evapotranspiration is projected to increase in winter but in summer to decrease over the oceans and increase over land. Increasing net precipitation increases river discharge to the Arctic Ocean. Over sea ice in summer, projected increase in rain and decrease in snowfall decrease the surface albedo and, hence, further amplify snow/ice surface melt. With reducing sea ice, wind forcing on the Arctic Ocean increases with impacts on ocean currents and freshwater transport out of the Arctic. Improvements in observations, process understanding, and modeling capabilities are needed to better quantify the atmospheric role in the Arctic water cycle and its changes.We thank all colleagues involved in the Arctic Freshwater Synthesis (AFS) for fruitful discussions. In particular, John Walsh is acknowledged for his constructive comments on the manuscript. AFS has been sponsored by the World Climate Research Programme’s Climate and the Cryosphere project (WCRP-CliC), the International Arctic Science Committee (IASC), and the Arctic Monitoring and Assessment Programme (AMAP). The work for this paper has been supported by the Academy of Finland (contracts 259537 and 283101), the UK Natural Environment Research Council (grant NE/J019585/1), the US National Science Foundation grant ARC-1023592 and the Program “Arctic” and the Basic Research Program of the Presidium Russian Academy of Sciences. NCAR is supported by the U.S. National Science Foundation. We gratefully acknowledge the project coordination and meeting support of Jenny Baeseman and Gwenaelle Hamon at the CliC International Project Office. No new data were applied in the manuscript. Data applied for Figures 2 and 3 are available from the JRA-55 archive at http://jra. kishou.go.jp/JRA-55/index_en. html#usage

Statistical process control

Statistical process control methods and possibility of their use to solve quality problems of the output products have been discussed in the article. Variability of the technological process and its effect on the output products quality have been characterized. Situations which claim interference in the technological process have been described. Different types of Shewhart control cards have been considered: simple control cards by variables and alternative attributes, cards with warning boundaries, cumulative sums cards, exponentially weighed moving averages cards. Besides univariate control cards, Hotteling multivariate control cards and cumulative sums cards which are used to control multi-parameter technological process are discussed in the article. Fields of application of different types of control cards are described

COMPARATIVE RESEARCHES OF FRACTURES OF HIGH-STRENGTH CAST IRON IN THE AS-CAST AND DEFORMED STATE

The results of comparative studies of fracture surfaces of high-strength cast iron in the as-cast state and after hot direct extrusion through an aperture of a conical die are presented.The shape change of graphite inclusions and components of the metal matrix is examined with increasing the reduction ratio from 0 (as-cast state) to 80%.For the fist time, using the electrochemical etching of the metal matrix of the cast iron, it is demonstrated experimentally that at plastic deformation the ductile flow of graphite inclusions occurs without fracturing of the latter. The surface morphology of a deformed graphite inclusion is revealed. It is shown that inside the inclusion the strain is distributed non-uniformly: the peripheral zones are deformed to a larger extent while the central part may retain its original radial structure.The fact that the most part of graphite inclusions on the fracture surface of the deformed cast iron appeared undamaged (very small amount of fractured inclusions was observed) testifies against the common opinion that graphite acts as a crack nucleation site. A hypothesis is put forward that the crack nucleates in the metal matrix, presumably at the pearlite/ferrite interface, and propagates from one graphite inclusion to another rounding but not damaging the latter