CAD/CAM, CNC TECHNOLOGY APPLIED IN THE FIELD OF ENGINEERING, SECURITY TECHNOLOGY AND MECHANICAL ENGINEER TRAINING I.

In the last decades the spectacular results of each developmental stages of computer-aided design, were considered as great magic of computer use. Professionals were shocked by the impressive building of engineer works and their more and more realistic appearance. It was hard to believe and for many people it still is that this technology becomes indispensable in everyday engineering work. By now, in front-rank product development, it is impossible to do a competitive designer work without applying the most up-to- date design technology. This all leads to the fact that an engineer student of our days, in his design practice, is definitely going to work with the momentarily most up-to-date technology, which will be out-of-date in a couple of years. | A számítógépek alkalmazásának nagy varázslatai közé számított az elmúlt évtizedekben a számítógépen végzett tervezés egy-egy fejlıdési szakaszának látványos eredménye. Szakembereket is meghökkentett a mérnöki alkotások látványos építése és mind valósághőbb megjelenítése. Nehezen hitték, sıt sokan ma is nehezen hiszik azt, hogy a mérnöki munka mindennapjaiban is nélkülözhetetlenné válik ez a technika. Mára az élvonalbeli termékfejlesztésben a mindenkori legjobb tervezési technika igénybevétele nélkül képtelenség versenyképes tervezımunkát végezni. Ennek következtében napjaink mérnökhallgatója tervezıi gyakorlatában minden bizonnyal a ma legkorszerőbbnek számító, de néhány év alatt elavuló módszert leváltó technikával fog dolgozni. Keywords/kulcsszavak: computer aided design, CAD1/CAM2, CNC3 ~ számítógépes tervezés, CAD/CAM, CN

Innovation – source to obtain the competitive advantage in the global economy

A strong motivation to replace the comparative advantage theory with the competitive advantage theory is given by the significant change of the present economic conditions comparing with the old conditions that inspired the competitive advantage issues. The dynamic character of the market competition and the fact that, in the present, the competitiveness is located to enterprise’s level and not to the level of the national economy are some important argues that sustain the necessity and the opportunity to move the economic thinking from the comparative advantage theory to the competitive advantage theory. In the past, the comparative advantage of an economy was given by the natural resources, by the geographical position or by the specific features of products or services. Nowadays the competitive advantage is created through innovation by all its forms.innovation, comparative advantage, competitive advantage

Disappearance of stretch-induced wrinkles of thin sheets: a study of orthotropic films

A recent paper (Healey et al., J. Nonlin. Sci., 2013, 23:777-805.) predicted the disappearance of the stretch-induced wrinkled pattern of thin, clamped, elastic sheets by numerical simulation of the F\"oppl-von K\'arm\'an equations extended to the finite in-plane strain regime. It has also been revealed that for some aspect ratios of the rectangular domain wrinkles do not occur at all regardless of the applied extension. To verify these predictions we carried out experiments on thin 20 micrometer thick adhesive covered), previously prestressed elastomer sheets with different aspect ratios under displacement controlled pull tests. On one hand the the adjustment of the material properties during prestressing is highly advantageous as in targeted strain regime the film becomes substantially linearly elastic (which is far not the case without prestress). On the other hand a significant, non-ignorable orthotropy develops during this first extension. To enable quantitative comparisons we abandoned the assumption about material isotropy inherent in the original model and derived the governing equations for an orthotropic medium. In this way we found good agreement between numerical simulations and experimental data. Analysis of the negativity of the second Piola-Kirchhoff stress tensor revealed that the critical stretch for a bifurcation point at which the wrinkles disappear must be finite for any aspect ratio. On the contrary there is no such a bound for the aspect ratio as a bifurcation parameter. Physically this manifests as complicated wrinkled patterns with more than one highly wrinkled zones on the surface in case of elongated rectangles. These arrangements have been found both numerically and experimentally. These findings also support the new, finite strain model, since the F\"oppl-von K\'arm\'an equations based on infinitesimal strains do not exhibit such a behavior.Comment: 16 pages, 5 figure

Autoregressive models for analysis of foreign investment in Romania

On the base of significant fluctuations of the international financial markets, the international investment position of Romania has an increasing importance in assuring the financial stability. The Romanian National Bank reserves are increasing as a result of exchanging the minimum reserves into foreign currencies made by banks and of the privatization revenues. The international reserve has been negatively influenced by the payments made in the foreign debt service account and by the foreign payment forms redeemed by the Public Finance Ministry. This paper offers to analyze the evolution and impact of the foreign investments in any form whatsoever, on the Romanian economy with the help of autoregressive econometrical models. These models shall refer to all foreign investments elements: direct investments of non-residents, portfolio investment and other categories of foreign investments as well as bank deposits or external short-term, medium and long-term credits.econometric analysis, foreign investment, autoregressive models