298 research outputs found
“The making of environmental policy in an Input-Output framework”, in Gorla and Percoco(a cura di), Politica ambientale, reti e territorio, EGEA (2005)
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Service industry and cumulative growth in the regions of Europe
No full textEuropean regions have experienced a greater presence of service producers in their economy over the last few decades. Indeed, the manufacturing sector increasingly contracts out many activities to intermediate producer services. This is mostly because they are located close to each other and because services experience increasing returns to scale which reduce their marginal costs. In this paper, we propose to measure the extent to which productivity in services has converged across European regions. The model we use, originally developed by Verdoorn (1949), takes the increasing returns to scale explicitly into account. We apply spatial econometric techniques and control for border effects by introducing two different spatial weights matrices under the assumption that economic interactions decrease very substantially when a national border is passed. Furthermore, we take proper care of the presence of both types (spatial and non-spatial) of endogeneity by using spatial two stages least squares (Kelejian and Prucha 1998). Our conclusions bring new insights in the identification of regional productivity differentials. © 2009 Taylor & Francis
Non-Newtonian, non-isothermal three-dimensional modeling of strand deposition in screw-based material extrusion
No full textThe European regional growth process revisited
No full textWith the 2004 enlargement to the East, the EU regional growth process can no longer be seen in the frame of the traditional core-periphery pattern. This is why this article proposes an innovative methodology to endogenously detect convergence clubs while accounting for spatial autocorrelation across regions. Our model is estimated on 244 EU25 regions over 1991-2003. Our results indicate that four distinctive clubs are present in our sample. In addition, the model we use does not rely on the traditional neoclassical model but on Verdoorn's law, which allows us to account for the presence of increasing returns to scale. Our conclusions give new insights for policy makers interested in convergence and regional policies developed to promote it
Digital close range photogrammetry for 3D body scanning for custom-made garments
No full textAmong several biometric applications, one of those currently attracting great interest is the possibility of carrying out 3D digitisation of human individuals to analyse their physical characteristics. These characteristics can be used for several purposes, such as security, medicine and tailoring for custom-made clothing. In recent years, although the development of online 3D scanning systems has been accelerating fast, little work has been devoted to offline systems, which would be particularly suitable for the textile and clothing industries. In the present research the author presents a specially designed low-cost offline 3D body digitiser, based on digital close range photogrammetry. A specially designed photogrammetric 3D scanner of the human body is presented, featuring automatic image processing procedures. The scanning system consists of eight cameras with a resolution of 5 megapixels, equipped with 16 mm wide-angle lenses; there are four white-light illuminators, of 100 W each. Tests on a tailor's dummy and on whole human bodies are reported, demonstrating the usefulness of the technique for textile applications. The digitisations performed on human bodies generally yield worse results than the corresponding ones on the dummy, and full body digitisations are worse than corset digitisations owing to the lower point density and to target distortion. Nevertheless, the results are satisfactory for tailoring applications that do not require high accuracies
An application- and market-oriented review on large format additive manufacturing, focusing on polymer pellet-based 3D printing
No full textSince this advent, additive manufacturing (AM) has grown steadily and found applications across all types of sectors. While the great development of such technologies has improved the quality of prints and expanded the availability of materials, AM still has some limitations regarding its physical scaling. This paper will briefly present the state-of-the-art of large-scale additive manufacturing and subsequently greater attention will be given to extrusion-based 3D printing. Specifically, we will discuss about large format additive manufacturing (LFAM) or big area additive manufacturing (BAAM), a technology based on material extrusion born a few years ago. These systems are characterized by higher deposition rate and lower costs of the material compared to fused filament fabrication (FFF) printers; moreover, they allow to obtain parts with better properties (e.g., adding carbon or glass fibers). The world of research has shown great interest in large-scale material extrusion technologies, which appear to be quite competitive with conventional manufacturing processes and which will find increasing application in the industrial field. With the aim of developing a tool for orienting researchers and technicians in this complex field, the present paper presents a systematic review of the actual market of machines, the research in extrudable materials and related applications concerning large-scale 3D printing, and in particular the LFAM
A multilevel approach to edge detection in tessellated point clouds
No full textMost rapid prototyping (RP) additive techniques are expensive and suffer from a lack of efficiency when massive products are to be manufactured. The authors propose to reduce the density of rapid prototyped parts, finding alternative building styles. Topologically optimized parts have been created with internal geometry, using a narrow-waisted structure that avoids the need for building supports. In order to characterise and study the behaviour of the obtained low density parts, an experimental plan has been designed and executed. The approach has been tested using a fused deposition modelling (FDM) machine, but it is of a general nature and can be applied to other layered manufacturing (LM) technologies that use supports, dealing with slow building of massive parts
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