31 research outputs found
Discussion on the thermal field produced by laser annealing for the residual stress relaxation
No full textIn this paper the temperature field generated on the surface of a metal by a focused laser source is analyzed. If the induced temperature distribution is properly designed the process can be used for obtaining local stress relaxation of the material. In order to determine the expected temperature distribution many parameters must be taken into account such as the power and the intensity distribution of the laser source, the duration of the irradiaton and the reflectivity of the surface at the specific wavelength. The influence of these parameters is numerically analyzed in this work. Temperature fields have been calculated for a point source and for a gaussian and a bi-gaussian beam in correspondence of different process parameters. Finally results in terms of stress relaxation for a given experimental configuration are presented based upon XRD residual stress measurements performed on an Al sample before and after the annealing process
DYNAMICS OF BRIDGE ASSEMBLIES
No full textA methodology is developed for making a dynamic analysis of a bridge assembly with the use of hybrid mathematical models. Obtained are the conditions of conjunction of the bearing structure and attached subsystems which take into account the length of the suspension section. The investigation gives consideration to the influence of the static stres-deformed state on the dynamic properties of the system. The optimum selection of the main design parameters of the bridge assembly served as a basis for minimizing the reaction of the system to the characteristic dynamic effects. This made it possible to reduce the level of vibration of tea-leaf harvesting devices and to provide for the required trajectory of their working membersAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio
Effects of stress concentration and occurrence of limit states under high speed loading in low temperature operating conditions
No full textLinearization and explicit solutions of the minimal surface equation
Get PDFWe show that the apparatus of support functions, usually used in convex surfaces theory, leads to the linear equation Ah+2h = 0 describing locally germs of minimal surfaces . Here A is the LaplaceBeltrami operator on the standard two-dimensional sphere . It explains the existente of the sum operation of minimal surfaces, introduced recently. In 4-dimensional space the equation Oh + 2h = 0 becomes inequality wherever the Gauss curvature of a minimal hypersurface is nonzero . Introduction Recently great progress was achieved in the investigation and construction of examples of minimal surfaces in R3 [1]-[3] . The Gauss map usually plays a significant role and its singularities in a sense control topology if the surface is complete In this paper, we show that apparatus of support functions usually used in convex surface theory leads to the linear and completely integradle equation of minimal surfaces in R3 . We are able to write down an explicit formula describing locally all minimal surfaces with nonvanishing curvature which is quite different from the Weierstrass description . We hope our method will be useful in global problems, too . It automatically implies the existente of the sum operation . The main part of this work was done during the author's visit to Lithuania in 1987. I wish to thank Professor F. Weiksa for fruitful discussions. I also wish to thank the referee for his very valuable remarks, in particular, for indicating to me that the relation of equatio
СТРУКТУРНЫЕ ПРОБЛЕМЫ ЭКОНОМИКИ КИТАЯ КАК ФАКТОР ИНЕРЦИОННОГО ТОРМОЖЕНИЯ ИНСТИТУЦИОНАЛЬНО-РЫНОЧНОЙ ПЕРЕСТРОЙКИ ЦЕПОЧЕК СОЗДАНИЯ ДОБАВЛЕННОЙ СТОИМОСТИ
No full textThe author conducts an empirical and theoretical analysis and understanding of the complexities of modern institutional and market restructuring value chains in the Chinese economy in the 2014-2020 period. Conclusively proves that the process of transformation of the modern chain cost savings in an open economy model is rigidly determined its strategy for economic growth and inclusion in the international production and commodity supply chains.В статье автор проводит эмпирико-теоретический анализ и осмысление современных сложностей институционально-рыночной перестройки цепочек создания добавленной стоимости в экономике Китая в 2014-2020 гг. Доказательно обосновывается, что процесс современной трансформации цепочек накопления стоимости в открытой экономике жестко детерминирован моделью ее экономического роста и стратегией включения в систему международной производственной и товарно-сбытовой кооперации
Role of Particle Shape, Substrate Streaming Potential and Ionic Strength in Kinetics and Spatial Distribution of Electrostatically Deposited Silver Nanoparticles
No full textThe electrostatic deposition of colloidal nanoparticles
is a powerful
way of constructing different types of composites, but its direct
mechanism is not reliably established. In this work, we demonstrate
correlations between the streaming potential of a polymeric substrate,
ionic strength of a solution, and shape of silver nanoparticles on
the one side and the deposition kinetics, optical properties, and
2D distribution of nanoparticles in the deposited layer on the other.
We show that, unlike nanoplates, the quasi-spherical shape of silver
nanoparticles and the low substrate streaming potential together with
the low ionic strength favor the ordering of 2D nanoparticle’s
ordering. We also demonstrate the correlation between the real 2D
distribution of nanoparticles and the distribution computed using
the extended random sequential adsorption model and Monte Carlo simulation,
highlighting the importance of electrostatic repulsion between nanoparticles
with different effective exclusion radius and shape
