4 research outputs found
Ensuring the reliability and performance criterias of crankshafts
The issues of efficiency improvement of manufacturing crankshafts in order to ensure their reliability and performance criteria are the priorities in modern production of internal combustion engines. Using the capabilities of modern special grinding machines can improve the quality of machining and obtain the necessary running characteristics of crankshafts. In work the questions connected with development of a method of calculation of rigidity of crankshafts for increase of accuracy of their machining, reliability and performance criteria’s are considered. Based on the proposed methodology, numerical calculations have performed and the possibility of determining the deflections and crankshafts rigidity in any section have been justified. The original construction of the following grinding steady rest for CNC grinding machines specified for machining the crankshaft main bearing journal and connecting rod journal is proposed. The construction design of the device allows for compensating the influence of the cutting force on the elastic strain of the part, depending on the change in its rigidity. The practical value of the research includes in develop recommendations for determining the optimal parameters for the round infeed grinding cycle of the crank pins from the point of view of productivity and accuracy
Magnetic Moment Collapse-Driven Mott Transition in MnO
The metal-insulator transition in correlated electron systems, where electron
states transform from itinerant to localized, has been one of the central
themes of condensed matter physics for more than half a century. The
persistence of this question has been a consequence both of the intricacy of
the fundamental issues and the growing recognition of the complexities that
arise in real materials, even when strong repulsive interactions play the
primary role. The initial concept of Mott was based on the relative importance
of kinetic hopping (measured by the bandwidth) and on-site repulsion of
electrons. Real materials, however, have many additional degrees of freedom
that, as is recently attracting note, give rise to a rich variety of scenarios
for a ``Mott transition.'' Here we report results for the classic correlated
insulator MnO which reproduce a simultaneous moment collapse, volume collapse,
and metallization transition near the observed pressure, and identify the
mechanism as collapse of the magnetic moment due to increase of crystal field
splitting, rather than to variation in the bandwidth.Comment: 18 pages, 5 figur
Ensuring the economic efficiency of enterprises by multi-criteria selection of the optimal manufacturing process
Technological assurance and improvement of the economic efficiency of production are the
first-priority issues for the modern manufacturing engineering area. It is possible to achieve
a higher value of economic efficiency in multiproduct manufacturing by multicriteria optimization. A set of optimality criteria based on technological and economic indicators was
defined with the aim of selecting the optimal manufacturing process. Competitive variants
and a system of optimization were developed and investigated. A comparative analysis of
the optimality criteria and their influence on the choice of optimal machining processes was
carried out. It was determined that the batch of parts made an impact on the selection of
the manufacturing process