Pontryagin Maximum Principle and Stokes Theorem

We present a new geometric unfolding of a prototype problem of optimal control theory, the Mayer problem. This approach is crucially based on the Stokes Theorem and yields to a necessary and sufficient condition that characterizes the optimal solutions, from which the classical Pontryagin Maximum Principle is derived in a new insightful way. It also suggests generalizations in diverse directions of such famous principle.Comment: 21 pages, 7 figures; we corrected a few minor misprints, added a couple of references and inserted a new section (Sect. 7); to appear in Journal of Geometry and Physic

Carbon budget of the vineyard \u2013 A new feature of sustainability

Vineyards received scarce attention in relation to the continuous monitoring of carbon fluxes and the assessment of their overall budget, as a common believe is that agricultural crops cannot be net carbon sinks. Indeed, many technical inputs, massive periodical harvests, and the repeated disturbances of upper soil layers, all contribute to a substantial loss both of the old and newly-synthesized organic matter. Woody perennials, however, can behave differently: they grow a permanent structure, stand undisturbed in the same field for decades, originate abundant pruning debris, and are often grass-covered. We have been monitoring the Net Ecosystem Exchange (NEE) by eddy covariance and the carbon partitioning in a temperate vineyard in North Eastern Italy. Five complete yearly budgets confirm a steady and substantial sink capacity of the system, with a yearly NEE around 800\u2013900 gC m 122, grape harvest representing about 20\u201325% of it. Biometrical assessment of growth and partitioning show a good agreement with micrometeorological measurements and demonstrate a large input of organic matter into the soil. Even if it can be objected that this sink may be only temporary and the built-up can be substantially disrupted at the end of the vineyard life cycle, these results show that there is a concrete possibility of storing carbon in temperate-climate vineyards, possibly contributing to the global carbon budget. This sink capacity might be accounted in the official calculation of wine carbon footprint and represents a new, relevant feature of their sustainability

Experimental investigation of inter-element isolation in a medical array transducer at various manufacturing stages

This work presents the experimental investigation of vibration maps of a linear array transducer with 192 piezoelements by means of a laser Doppler vibrometer at various manufacturing finishing steps in air and in water. Over the years, many researchers have investigated cross-coupling in fabricated prototypes but not in arrays at various manufacturing stages. Only the central element of the array was driven at its working frequency of 5 MHz. The experimental results showed that the contributions of cross-coupling depend on the elements of the acoustic stack: Lead Zirconate Titanate (PZT), kerf, filler, matching layer, and lens. The oscillation amplitudes spanned from (6 ± 38%) nm to (110 ± 40%) nm when the energized element was tested in air and from (6 ± 57%) nm to (80 ± 67%) nm when measurements were obtained under water. The best inter-element isolation of -22 dB was measured in air after cutting the kerfs, whereas the poorest isolation was -2 dB under water with an acoustic lens (complete acoustic stack). The vibration pattern in water showed a higher standard deviation on the displacement measurements than the one obtained in air, due to the influence of acousto-optic interactions. The amount increased to 30% in water, as estimated by a comparison with the measurements in air. This work describes a valuable method for manufacturers to investigate the correspondence between the manufacturing process and the quantitative evaluations of the resulting effects

Relativistic approach to one nucleon knockout reactions

We develop a fully relativistic distorted wave impulse approximation model for electron- and photon-induced one proton knockout reactions. The relativistic mean field for the bound state and the Pauli reduction for the scattering state are used, including a fully relativistic electromagnetic current operator. Results for 16O(e,e'p) cross section and structure functions are shown in various kinematic conditions and compared with nonrelativistic calculations. Nuclear transparency calculations in a Q^2 range between 0.3 and 1.8 (GeV/c)^2 are presented. Results for 16O(gamma,p) differential cross sections are displayed in an energy range between 60 and 150 MeV including two-body seagull contribution in the nuclear current.Comment: 4 pages, 4 figures, REVTeX4. Talk presented by Andrea Meucci at the IX Workshop on Theoretical Nuclear Physics in Italy, Cortona, Italy, 9-12 October 200

DESIGN TOOLS FOR LIFE CYCLE ANALYSIS AND DURABILITY EVALUATION OF BUILDING SYSTEMS: A RESEARCH ON THE BUILDING ENVELOPE

The behavior and service life prediction of building systems requires to develop tools to assist the designer. The paper is focused on a research carried out in the Department of Architecture and Design with the Department of Mathematical Sciences of the Politecnico di Torino. The goal is to develop a design tool to forecast the building subsystem durability and to help the designer in design options. The method is based on FMEA (Failure Mode and Effect Analysis) developed in a qualitative way as well as in a probabilistic way. The analyst assess the functional models, the failures and the consequent predicted service life of components. The designer will select materials defining the risk coming from environmental agents, design, materials and workmanship. The estimated service life has been assessed by Monte Carlo method. The external walls was the example tested using data by investigations in the area of northern Italy and from literature

Strange quark effects in electron and neutrino-nucleus quasi-elastic scattering

The role of the sea quarks to ground state nucleon properties with electroweak probes is discussed. A relativistic Green's function approach to parity violating electron scattering and a distorted-wave impulse-approximation applied to charged- and neutral-current neutrino-nucleus quasi-elastic scattering are presented in view of the possible determination of the strangeness content of the nucleon.Comment: 6 pages, 3 figures, talk given at 11th Conference on Problems in Theoretical Nuclear Physics, Cortona, Italy, 11-14 October 200

Italian Firms in History: Size, Technology and Entrepreneurship

The economic performance of a country depends, among other things, on the strategies and structures of its firms. In the framework that is designed by institutions and policies and determined by technology and macroeconomic cycles, entrepreneurs decide how to allocate available resources in order to face off competitors and to hook up with demand cycles. This paper looks at the evolution of the Italian economy across the last 150 years from a business history perspective. Analyzing Italian firms over the long-term cycles of the global economy and with respect to the different paradigms of the three industrial revolutions, we identify some structural features that explain successes and failures of the Italian economy. In doing this we explicitly connect the micro level of the business enterprise to the macro one of the national business system and explain the comparatively good performance of the Italian economy from the end of the 19th century to the 1970s. Over the last three decades this performance has turned negative, highlighting the role played by the small average size of firms and the failure of institutions to provide incentives for growth.firm size, technological paradigms, innovation, entrepreneurship