45 research outputs found
On the Possibility of Describing the Microstructure of Human Dentin as Soft Matrix Filled by Solid Particles
On the Possibility of Describing the Microstructure of Human Dentin as Soft Matrix Filled by Solid Particles
Experimental verification of the applicability of self-similar hierarchical mechanics model for calculation of the mechanical properties of human dentin was carried out. A comparison of the deformation behavior of human dentin with the several polymer based dental composites under compression and bending was performed. It was shown that the deformation behavior of some highly filled composites was close to human dentin in the elastic regime whereas they cannot be deformed plastically under compression. Low filled composites possess higher plasticity, but a lower Young's modulus than dentin under compression. Mechanical properties of a highly filled composite (∼60%, by volume) with smaller size of fillers are closer to the properties of human dentin under bending whereas other tested dental materials have a lower Young's modulus and flexural strength in comparison with dentin. Therefore, we concluded that it was impossible to achieve complete combination of the mechanical properties of human dentin such as high elasticity and plasticity at high strength by means of varying the amount and size of solid filler in polymer matrix. Self-similar hierarchical mechanics model can be used for describing of the deformation behavior of human dentin in elastic regime and one level is sufficient for these calculations. © Published under licence by IOP Publishing Ltd.The reported study was supported by RFBR, research project No. 20-48-660017
Short Range Radar with MIMO Antenna System and Multifrequency Sounding Signal
Abstract-Algorithms of slow moving objects allocation on a background of motionless local objects reflections in MIMO radar with radiation of orthogonal signals by transmitting elements of the multielement antenna system are offered. Results of laboratory experiments with created breadboard model of MIMO small range radar with eight-elements transmitting and receiving linear antenna arrays at radiation of sounding signals with step frequency modulation are given
Optimization of quality of the aesthetic and functional restorations at early stage of increased abrasion of teeth
In the article presents the results of clinical application of composite materials increased conversion compared to traditional composite materials and indirect CAD / CAM restorations of posterior teeth at worn dentition. Proven increase in the quality of the seals 1.6 times in the selection of preheated technique composites compared with the traditional one.В статье представлены результаты клинического применения композиционных материалов повышенной конверсии в сравнении в традиционным композитным материалом и непрямыми CAD/CAM реставрациями боковой группы зубов при повышенной стираемости I степени. Доказано повышение качества пломб в 1,6 раза при выборе методики восстановления композитами повышенной конверсии по сравнению с традиционной
Antipersonnel Landmines Detection by Holographic Radar Imaging: An Experimental Study of Soil Effects
Possibilities of navigation surgery in rehabilitation of dental patients (literature review)
With the advent of imaging technologies and CAD/CAM technologies, the possibility of digital surgery has become of wide interest among implantologists. The article discusses the methods of rehabilitation of a dental patient by implantation according to a surgical template. The advantages and disadvantages of the digital protocol in comparison with the traditional operation of dental implantation are highlighted
Обеспечение безопасности перевозок с помощью средств дистанционного зондирования
ABSTRACT Improving safety of rail transportation in the face of increasing speeds and traffic intensity and the presence of a terrorist threat requires introduction of new technical means of surveillance and control. A particular task is development of measures to prevent accidents and catastrophes, as well as to eliminate their consequences. The use of Earth remote sensing means, which allow to receive information from large areas and with a sufficiently high resolution, can significantly help in implementation of these tasks. The article deals with variants of satellites and remotely piloted aircrafts systems receiving information in various ranges of the electromagnetic spectrum. Their advantages and disadvantages, opportunities of joint use are analyzed. Keywords: rail transportation safety, remote sensing of the Earth, satellites, remotely-piloted aircraft, aerial photography, radar sounding, image processing. The study was carried out with the financial support of the Russian Foundation for Basic Research in the framework of the scientific project No. 17-20-02086. The authors are grateful to the staff of the Experimental Railway Ring in Shcherbinka for their assistance in conducting RPA flights to obtain the necessary information.Полный текст на англ. языке находится в прилагаемом файле ПДФ (англ. версия следует после русской версии).Повышение безопасности железнодорожных перевозок в условиях растущих скоростей и интенсивности движения составов и при наличии террористической угрозы требует внедрения новых технических средств наблюдения и контроля. Особую задачу представляет разработка мер предотвращения аварий и катастроф, а также ликвидации их последствий. Применение средств дистанционного зондирования Земли, позволяющих оперативно получать информацию с больших площадей и с высоким разрешением, может оказать существенную помощь в этой сфере. В статье рассматриваются варианты спутников и дистанционно- пилотируемых летательных аппаратов, получающих информацию в различных диапазонах электромагнитного спектра. Анализируются их достоинства и недостатки, возможности совместного использования. Исследование выполнено при финансовой поддержке РФФИ в рамках научного проекта № 17-20-02086. Авторы выражают благодарность сотрудникам Экспериментального железнодорожного кольца в г. Щербинка за содействие в проведении полётов ДПЛА для получения необходимой информации
Интеллектуальный видеоанализ опасных ситуаций
[For the English abstract and full text of the article please see the attached PDF-File (English version follows Russian version)].The work was supported by the Russian Foundation for Basic Research (Grant No. 17-20-03034). ABSTRACT The article is devoted to development of a system for the intelligent analysis of video recordings of external surveillance cameras, which makes it possible to identify dangerous situations at railway facilities using the example of detection of falls in the track area. A method of preprocessing a video for the purpose of forming a feature space based on the use of background subtraction using the Gaussian mixture method, followed by tracking the movement of a person with the help of the Kalman filter and deformation of the shape of the mobile object as a result of applying the procrustean analysis is proposed. The selection of the optimal composition of the feature space and additional heuristics providing the isolation of episodes of falls from video recording with an average quality of the Cohen’s kappa 0,62 is compared with the visual analysis by the operator. Keywords: railway, safety, video surveillance, intelligent video analysis, motion recognition, machine learning, form analysis.Текст аннотации на англ. языке и полный текст статьи на англ. языке находится в прилагаемом файле ПДФ (англ. версия следует после русской версии).Работа выполнена при поддержке Российского фонда фундаментальных исследований (грант № 17-20-03034). Статья посвящена разработке системы интеллектуального анализа видеозаписей камер наружного наблюдения, позволяющей выявлять опасные ситуации на объектах железных дорог на примере детекции падений в зоне пути. Предложен метод предобработки видеоряда с целью формирования пространства признаков, основанный на использовании вычитания фона по методу гауссовой смеси, последующем отслеживании перемещения человека при помощи фильтра Калмана и деформации формы подвижного объекта в результате применения прокрустова анализа. Обоснован подбор оптимального состава пространства признаков и дополнительных эвристик, обеспечивающих выделение эпизодов падений по видеозаписи со средним качеством каппы Коэна 0,62 по сравнению с визуальным анализом оператором