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1 – 2 of 2Natalia A Kravchenko, Svetlana A Kuznetsova, Almira Yusupova, Thadavillil Jithendranathan, Lorman L Lundsten and Arkady Shemyakin
– The purpose of this paper is to conduct comparative research of small innovative entrepreneurship under different types of institutional environment in Russia and the USA.
Abstract
Purpose
The purpose of this paper is to conduct comparative research of small innovative entrepreneurship under different types of institutional environment in Russia and the USA.
Design/methodology/approach
A survey was administered among small innovative firms in the State of Minnesota (USA) and Novosibirsk Oblast (Russia). Mann-Whitney test for median differences adjusted for multiple comparisons using Benjamini-Hochberg procedure is used to establish statistically significant dissimilarities between Siberian and Minnesotan populations.
Findings
The results indicate that there are significant differences in the challenges faced by the Russian and American firms. The most important among them are the lack of legal structure for innovation and availability of qualified staff in Russia.
Research limitations/implications
The study is limited to two regions with comparable economic and geographic environments.
Practical implications
It is indicated in the results that significant changes in institutional business environment are necessary for the future development of innovative entrepreneurship in Russia.
Originality/value
This study is the first of its kind to compare the challenges facing small innovative entrepreneurship in Russia and the USA.
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Keywords
Sergey Shevtsov, Igor V. Zhilyaev, Ilya Tarasov, Jiing-Kae Wu and Natalia G. Snezhina
The purpose of this paper is to develop the multi-objective optimization approach and its numerical implementation to synthesise the model-base control for the part curing at…
Abstract
Purpose
The purpose of this paper is to develop the multi-objective optimization approach and its numerical implementation to synthesise the model-base control for the part curing at autoclave processing, which supplies the stability and uniformity of the structure and mechanical properties of the material within the cured composite part.
Design/methodology/approach
The approach includes conversion of the cured part and mold geometry from their computer-aided design (CAD) to computer-aided engineering (CAE) representation, a finite element (FE) formulation of the coupled forward heat transfer/thermal kinetic problem with the parameters of prepreg, which should be determined by the thermal analysis, and, finally, a mapping of the area of 4D design space (thermal control parameters) to 2D objective space, whose coordinates are the maximum deviations of degree of cure and temperature within the cured part calculated at each call of the FE model.
Findings
The present modeling and optimization approach to the cure process control of the prepreg with thermosetting resin, as well as the means of visualizing optimization results, allow providing insight into complex curing phenomena, estimating the best achievable quality indicators of manufactured composite parts, finding satisfactory parameters of the control law and deciding considering all manufacturing constraints.
Research limitations/implications
The research can be effectively used to optimize the cure process control for a wide class of polymeric composite parts, even with a complex geometry, but it requires the exact conversion of the geometry of the modeled part from the CAD to CAE environment, which implies the need for excluding all topological imperfections of original CAD model to eliminate the possible formation of void elements and other reasons that do not allow the correct FE meshing. Because thermal, rheological and kinetics parameters, which include the governing equations of cure process, depend on the reinforcing fibers, and especially on the resin properties, the thermal testing for the new modeled prepreg needs to be performed.
Practical implications
Computer implementation of the proposed approach and numerical method for model-based optimal control synthesis for composite part cure process can be used in aircraft, rotorcraft, ship and automotive technologies at the design of manufacturing process of the large composite parts with complex shape.
Social implications
This will allow much better quality for large-scale composite parts, excluding very expensive, time-, energy- and material-consuming multiple cure process testing.
Originality/value
This is first time the problem of optimal control synthesis for curing the large-scale composite parts of complex shape was solved.
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