881 research outputs found

    Industrial policies in Europe: an introduction

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    As guest editors of this Special Issue of PE/JEP we have selected a small number of rather detailed assessment of contemporary history of domestic industrial policies in the international context. The four papers included in this Special Issue can be seen as three case studies of “sectoral” innovation policies (broad band, wind energy, biotechnology) with a strong emphasis on country institutional features and policy instruments, together with one “horizontal” case of industrial policy in a specific country context (innovative startups in Italy). The heterogeneous theoretical background (industrial organization, evolutionary theory of the firm, economics of innovation, development) provides a somewhat unifying hidden thread of these case studies, without becoming a subject of analysis per se. This approach has been our intentional editorial choice and we are fully aware of its limitations. After very short non-technical summaries of the four papers (Section 1) we try to present a rather synthetic assessment of our personal views (largely shared among us even with partial minor disagreements) about the increasingly hot debate on the nature, limitations and desirable perspectives of industrial policy today. We argue for a non-ideological forward-looking role of governments as active players in helping domestic entrepreneurial resources not only to fully exploit inherited comparative advantages but also to face structural uncertainties and discover own potential competitive advantages in a rapidly changing international context (Section 2)

    Novel Deterministic Detection and Estimation Algorithms for Colocated Multiple-Input Multiple-Output Radars

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    In this manuscript, the problem of detecting multiple targets and estimating their spatial coordinates (namely, their range and the direction of arrival of their electromagnetic echoes) in a colocated multiple-input multiple-output radar system operating in a static or slowly changing two-dimensional or three-dimensional propagation scenario is investigated. Various solutions, collectively called range & angle serial cancellation algorithms, are developed for both frequency modulated continuous wave radars and stepped frequency continuous wave radars. Moreover, specific technical problems experienced in their implementation are discussed. Finally, the accuracy achieved by these algorithms in the presence of multiple targets is assessed on the basis of both synthetically generated data and of the measurements acquired through three different multiple-input multiple-output radars and is compared with that provided by other methods based on multidimensional Fourier analysis and multiple signal classification

    An Approximate Maximum Likelihood Method for the Joint Estimation of Range and Doppler of Multiple Targets in OFDM-Based Radar Systems

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    In this manuscript, an innovative method for the detection and the estimation of multiple targets in a radar system employing orthogonal frequency division multiplexing is illustrated. The core of this method is represented by a novel algorithm for detecting multiple superimposed two-dimensional complex tones in the presence of noise and estimating their parameters. This algorithm is based on a maximum likelihood approach and combines a single tone estimator with a serial cancellation procedure. Our numerical results lead to the conclusion that the developed method can achieve a substantially better accuracy-complexity trade-off than various related techniques in the presence of closely spaced targets

    Deterministic Signal Processing Techniques for OFDM-Based Radar Sensing: An Overview

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    In this manuscript, we analyze the most relevant classes of deterministic signal processing methods currently available for the detection and the estimation of multiple targets in a joint communication and sensing system employing orthogonal frequency division multiplexing. Our objective is offering a fair comparison of the available technical options in terms of required computational complexity and accuracy in both range and Doppler estimation. Our numerical results, obtained in various scenarios, evidence that distinct algorithms can achieve a substantially different accuracy-complexity trade-off

    Special nuclear material detection studies with the SMANDRA mobile system

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    The detection of special nuclear material has been studied with the SMANDRA mobile inspection system used both as a high sensitivity passive neutron/gamma spectroscopic tool and as an active inspection device using tagged neutrons. The detection of plutonium samples is possible with passive interrogation, the passive detection of uranium being much more difficult because of the low neutron yield and of the easiness of shielding the gamma rays. However, we show that active interrogation with tagged neutrons is able to provide signatures for the discrimination of uranium against other materials

    Laboratory Tests of Low Density Astrophysical Equations of State

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    Clustering in low density nuclear matter has been investigated using the NIMROD multi-detector at Texas A&M University. Thermal coalescence modes were employed to extract densities, ρ\rho, and temperatures, TT, for evolving systems formed in collisions of 47 AA MeV 40^{40}Ar + 112^{112}Sn,124^{124}Sn and 64^{64}Zn + 112^{112}Sn, 124^{124}Sn. The yields of dd, tt, 3^{3}He, and 4^{4}He have been determined at ρ\rho = 0.002 to 0.032 nucleons/fm3^{3} and TT= 5 to 10 MeV. The experimentally derived equilibrium constants for α\alpha particle production are compared with those predicted by a number of astrophysical equations of state. The data provide important new constraints on the model calculations.Comment: 5 pages, 3 figure

    Experimental Determination of In-Medium Cluster Binding Energies and Mott Points in Nuclear Matter

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    In medium binding energies and Mott points for dd, tt, 3^3He and α\alpha clusters in low density nuclear matter have been determined at specific combinations of temperature and density in low density nuclear matter produced in collisions of 47AA MeV 40^{40}Ar and 64^{64}Zn projectiles with 112^{112}Sn and 124^{124}Sn target nuclei. The experimentally derived values of the in medium modified binding energies are in good agreement with recent theoretical predictions based upon the implementation of Pauli blocking effects in a quantum statistical approach.Comment: 5 pages, 3 figure

    PADC Detected External Neutron Field by Nuclear Tracks at RFX-mod

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    Measured neutron signals relevant for plasma diagnostics on Reversed Field pinch eXperiment, RFX-mod, are obtained by nuclear track methodology with PADC-NtD’s. this technique provides the external neutron field values around the RFX-mod installation during pulsed operation. Charged particles from (n, p) and (n, α) reactions are related to formed latent tracks. these are etched in a thermoregulated water bath with a 6.25M, KOh solution at 60oC. Observed tracks were analyzed to determine track density from which neutron fluence spatial values should be derived. Results indicate that the neutron density in the surrounding environment change at most 40%. the epithermal component is 60% higher than that corresponding to the thermal region. the estimated neutron fluence for the whole experiment is 7.5×1010 neutrons cm2/s

    Critical Behavior in Light Nuclear Systems: Experimental Aspects

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    An extensive experimental survey of the features of the disassembly of a small quasi-projectile system with AA \sim 36, produced in the reactions of 47 MeV/nucleon 40^{40}Ar + 27^{27}Al, 48^{48}Ti and 58^{58}Ni, has been carried out. Nuclei in the excitation energy range of 1-9 MeV/u have been investigated employing a new method to reconstruct the quasi-projectile source. At an excitation energy \sim 5.6 MeV/nucleon many observables indicate the presence of maximal fluctuations in the de-excitation processes. The fragment topological structure shows that the rank sorted fragments obey Zipf's law at the point of largest fluctuations providing another indication of a liquid gas phase transition. The caloric curve for this system shows a monotonic increase of temperature with excitation energy and no apparent plateau. The temperature at the point of maximal fluctuations is 8.3±0.58.3 \pm 0.5 MeV. Taking this temperature as the critical temperature and employing the caloric curve information we have extracted the critical exponents β\beta, γ\gamma and σ\sigma from the data. Their values are also consistent with the values of the universality class of the liquid gas phase transition. Taken together, this body of evidence strongly suggests a phase change in an equilibrated mesoscopic system at, or extremely close to, the critical point.Comment: Physical Review C, in press; some discussions about the validity of excitation energy in peripheral collisions have been added; 24 pages and 32 figures; longer abstract in the preprin
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