Моделирование механических свойств костных тканей челюсти и расчет напряженно-деформированного состояния зубочелюстных систем с искусственными включениями
The methods of biomechanical systems design with artificial elements are analyzed. The data of high-precision measurements of all set of the biometric characteristics, determining of biomechanical system is a basis of mathematical model. The calculations allows to predict complications at denture installation.
The influence of neutron irradiation on the mechanical properties of vanadium and the alloys V-10.6 Ti and V-10 Ti-6 Cr-0.05 Zr is investigated. Alloy samples are irradiated in the pile of a BOR-60 reactor to a fluence of (0.8-1)·10 22 cm -2 (E > 0.1 MeV) at 350°C. The results show that the irradiation of vanadium and its alloys in these conditions leads to insignificant (less than 0.1%) swelling but changes their mechanical properties (strength and plasticity). The radiational strengthening is greatest for pure vanadium and least for the alloy V-10.6 Ti. Adding chromium to the alloy reduces the positive effect of titanium and leads to low-temperature radiational embrittlement in the range 20-100°C. As shown by electron-microscope investigation, the change in mechanical properties of the alloys after irradiation is associated with the formation of a dislocational structure and with radiation-stimulated segregation.
The swelling and mechanical properties of vanadium and V-Ti (10-35 at. % Ti) and V-Ti-Cr (20 at. % Ti, 10 at. % Cr) alloys after neutron irradiation in the BOR-60 fast reactor to a total fluence of 1023 neutron/cm2 in the temperature range 350-830°C are studied. The samples are irradiated in sealed lithium-filled ampules. The swelling of the vanadium and alloy samples after irradiation is no more than 0.2%. Adding 10-35 at. % Ti to vanadium suppresses the low-temperature radiational embrittlement of the alloy; this effect is greatest with 35 at. % Ti. In the temperature range 700-1000°C, high-temperature radiational embrittlement appears in the alloy with 35 at. % Ti, but not in the alloy with 10 at. % Ti. Simultaneous alloying with 20 at. % Ti and 10 at. % Cr leads to the appearance of low-temperature radiational embrittlement of the alloy. The variation in the mechanical properties of the alloys on neutron irradiation is analyzed, taking account of the phase diagrams, and the limiting titanium and chromium content in the alloy is determined
Computer simulation of mechanical testing is used primarily for the correct interpretation of their results and is particularly relevant in cases, when the properties of the material during deformation are essentially nonlinear. For example: when we study mechanical properties of materials with high rate sensitivity. First of all it is superplastic titanium alloys. Superplastic materials exhibit the ability to severe plastic deformation without discontinuities if forming occurs in a narrow range of strain rates, specific to each alloy and temperature-dependent. In the study of superplastic materials, it’s necessary to maintain a constant rate of deformation of the sample. This is achieved by conducting an experiment with a special program loading, crosshead speed at which change during the experiment.
The Conference “Mathematical Modeling and Computational Physics 2015” is jointly organized by the Joint Institute for Nuclear Research (JINR), Dubna, Russia, the Technical University (TU), Institute of Experimental Physics SAS, the Pavol Jozef Šafárik University (UPJŠ), Košice, Slovakia, and the IFIN-HH, Bucharest, Romania.
The Conference follows the rich traditions of the previous conferences on mathematical modeling, numerical methods and computational physics that have been held in Dubna, Russia and also in Slovakia since 1964, e.g., Computational Modeling and Computing in Physics 1996, Modern Trends in Computational Physics 1998, V. International Congress on Mathematical Modeling 2002, Mathematical Modeling and Computational Physics 2006, 2009, 2011, and 2013. This year Conference is dedicated to the 60th anniversary of JINR.
Effects of the content of impurities such as Fe, Al, and Si on the mechanical properties, recrystallization temperature, and grain growth of binary alloys of vanadium with 10-35 at. % Ti were determined for various annealing conditions. The alloys for the investigation were melted using vanadium of two grades: VnM-1 aluminothermic vanadium remelted in a vacuum (the content of impurities of Fe, Al, and Si no more than ∼0.42 wt % in total) and VEL-2 electrolytic vanadium (the total content of impurities ∼0.06 wt %). The use of aluminothermic vanadium to prepare V-Ti alloys leads to a certain increase in their strength properties, especially in the range of low temperatures, and virtually does not affect the recrystallization temperature and grain growth in the alloys. The smallest grain growth is characteristic of the alloy containing 10 at. % Ti, which is due to the blocking effect of precipitates of oxynitride phases at grain boundaries.
This paper is devoted to mathematical modelling of the progression and stages of breast cancer. The Consolidated mathematical growth Model of primary tumor (PT) and secondary distant metastases (MTS) in patients with lymph nodes MTS (Stage III) (CoM-III) is proposed as a new research tool. The CoM-III rests on an exponential tumor growth model and consists of a system of determinate nonlinear and linear equations. The CoM-III describes correctly primary tumor growth (parameter T) and distant metastases growth (parameter M, parameter N). The CoM-III model and predictive software: a) detect di erent growth periods of primary tumor and distant metastases in patients with lymph nodes MTS; b) make forecast of the period of the distant metastases appearance in patients with lymph nodes MTS; c) have higher average prediction accuracy than the other tools; d) can improve forecasts on survival of breast cancer and facilitate optimisation of diagnostic tests. The CoM-III enables us, for the rst time, to predict the whole natural history of PT and secondary distant MTS growth of patients with/without lymph nodes MTS on each stage relying only on PT sizes.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.