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In the last decade, the adoption of additive manufacturing technologies (AMT) (3D printing) has increased significantly in many fields of engineering, initially only for rapid prototyping and more recently also for the production of finished parts. With respect to the long-established material subtractive technologies (MST), AMT is capable to overcome several limitations related to the shape realization of high-performance mechanical components such as those conceived via topology optimization and generative design approaches. In the field of structures and mechanisms, a major advantage of AMT over MST is that, for the same loading and constraining conditions (including kinematic and overall encumbrance), it enables the realization of mechanical components with similar stiffness but smaller volume (thus smaller weight, density being equal). Recently, the potentialities of AMT have also been increased by the introduction of the fuse filament deposition modeling (FDM) of continuous fibre-reinforced thermoplastics (CFRT), which combines the ease of processing of plastic AMT with the strength and specific modulus of the printed components that are comparable to those attainable via metallic AMT. In this context, the present paper investigates the potentialities of FDM-CFRT for the realization of mechanisms subjected to predominant inertial loads such as those found in automated packaging machinery. As a case study a Stephenson six-bar linkage powered in direct drive by a permanent magnet synchronous motor is considered. Starting from an existing mechanism realized in aluminum alloy with traditional MST, a newer version to be realized with FDM-CFRT has been conceived by keeping the kinematics fixed and by redesigning the links via three-dimensional topology optimization. To provide a fair comparison with the more traditional design/manufacturing approach, size optimization of the original mechanism made in aluminum alloy has also been performed. Comparison of the two versions of the mechanism highlights the superior performances of the one manufactured via FDM-CFRT in terms of weight, motor torque requirements and motion precision.

Activity recognition plays a key role in providing activity assistance and care for users in smart homes. In this work, we present an activity recognition system that classifies in the near real-time a set of common daily activities exploiting both the data sampled by sensors embedded in a smartphone carried out by the user and the reciprocal Received Signal Strength (RSS) values coming from worn wireless sensor devices and from sensors deployed in the environment. In order to achieve an effective and responsive classification, a decision tree based on multisensor data-stream is applied fusing data coming from embedded sensors on the smartphone and environmental sensors before processing the RSS stream. To this end, we model the RSS stream, obtained from a Wireless Sensor Network (WSN), using Recurrent Neural Networks (RNNs) implemented as efficient Echo State Networks (ESNs), within the Reservoir Computing (RC) paradigm. We targeted the system for the EvAAL scenario, an international competition that aims at establishing benchmarks and evaluation metrics for comparing Ambient Assisted Living (AAL) solutions. In this paper, the performance of the proposed activity recognition system is assessed on a purposely collected real-world dataset, taking also into account a competitive neural network approach for performance comparison. Our results show that, with an appropriate configuration of the information fusion chain, the proposed system reaches a very good accuracy with a low deployment cost.

Marinellite, a cancrinite-group mineral with ideal composition [(Na,K)42Ca6](Si36Al36O144)(SO4)8Cl26•H2O was reported for the firts time (Bonaccorsi and Orlandi, 2003) from Valle Biachella, Sacrofano (Roma, Italy). The crystal structure of marinellite [P31c with a = 12,880(2) Å and c = 31,761(6) Å] is characterized by columns of liottite cages running along [0, 0, z] and columns of cancrinite + sodalite cages staked along [1/3, 2/3, z] and [2/3, 1/3, z]. Na+, Ca2+ and K+, SO42- and Cl- are hosted within the liottite cages, while additional H2O and Na+ are hosted within the cancrinite cages. We describe here a new occurrence of marinellite from Magliano Romano, Sabatini Volcanic Complex north of Rome. The mineral is found as millimetric-sized, transparent to trasluncent, vitreous, light-blue colored, anhedral grains, within holocrystalline volcanic ejecta associated with biotite, clinopyroxene, and Fe-oxides. Powder diffraction data were collected with a Scintag X1 diffractometer (CuKα, solid state detector); EMP analyses were done using a CAMEBAX 50X WDS-microprobe (15 kV accelerating voltage, 4 nA beam current, spot size 20 μm). Powder-FTIR spectra were collected on KBr pellets with a spectrometer Nicolet Magna 760 (KBr beamsplitter, DTGS detector, Globar source); polarized micro-FTIR single crystal spectra were collected on oriented, doubly-polished slabs, using a NicPlan microscope equipped with a nitrogen-cooled MCT detector and a ZnSe wire-grid IR polarizer. The cell parameters: a = 12,881(1) Å, c = 31,764(4) Å, V = 4564,3(7) Å3, and the chemical formula of marinellite from Magliano Romano: (Na29.97K11.57Ca6.55)=48.09(Si35.93Al36.07)=72.00O144[(SO4)7.93Cl1.65(CO3)0.52]=10.11•5.77H2O, are close to those of the holotype specimen from Valle Biachella. Powder-FTIR spectra show the absorptions due to H2O (1/3 at 3500 cm-1 and 2 at 1630 cm-1), SO4 (3 at  1100 cm-1) and the alumino-silicate framework ( 1000 cm-1 and below). Single crystal polarized FTIR spectra shows the absorptions due to CO3 groups (3  1400 cm-1), H2O molecules, and two very unusual absorptions, due to molecular CO2 (Della Ventura et al. 2005, 2007a, 2007b), at 2352 and 2341 cm-1. The first component is almost completely polarized for E  c, while the second one has an isotropic behaviour. The polarization behavior of H2O stretching and bending bands is quite complex and shows the presence of two different water molecules within the structural channels, in agreement with the presence of two bending absorptions at around 1630 cm-1. References Bonaccorsi E., Orlandi P. (2003) Eur. J. Mineral., 15, 1019-1027. Della Ventura, G., Bellatreccia, F. and Bonaccorsi, E. (2005) Eur. J. Mineral., 17, 847-851. Della Ventura G., Bellatreccia F., Parodi G.C., Cámara F., Piccinini M. (2007a) Am. Mineral. (in press). Della Ventura G., Bellatreccia F., Piccinini M. (2007b) Rend. Fis. Acc. Lincei (in press).

After some introductory comments relating to antiferromagnetism of crystalline O_2, and brief remarks on the geometry of ozone, Hartree-Fock (HF) theory plus second-order Moller-Plesset (MP2) corrections are used to predict the nuclear structure of low-lying isomers of free-space O_n clusters, for n=6, 8, and 12. The equilibrium nuclear-nuclear potential energy is also discussed in relation to the number n of oxygen atoms in the cluster., To appear in Phys. Lett. A

Motivated by the theoretical study of Saito and Ono (2011) on three crystalline forms of SiO2 under pressure, quantum-chemical calculations on various free-space clusters of SiOn and GeOn for 1 < n

Motivated by the theoretical study of Saito and Ono (2011) on three crystalline forms of SiO2 under pressure, quantum-chemical calculations on various free-space clusters of SiOn and GeOn for 1 < n, Comment: Phys. Lett. A, to appear

Motivated by the theoretical study of Saito and Ono (2011) on three crystalline forms of SiO2 under pressure, quantum-chemical calculations on various free-space clusters of SiOn and GeOn for 1 < n, Phys. Lett. A, to appear

A crystalline form of LiBC is known which has been predicted to be superconducting, with a Tc comparable to that of MgB_2. In both compounds, superconductivity is enhanced by the presence of two electronic bands, one of which is close to a dimensional crossover. Here, we take a quantum chemical approach, and investigate the structural and electronic properties of small clusters (LiBC)_n (n=1-4). With increasing cluster size, we find that several properties of crystalline LiBC evolve naturally from the corresponding properties of the clusters. In particular, one may recognize the origin of the solid bilayered structure, typical of magnesium diboride, and the character of the electronic sigma-band, arising from the overlap of the atomic orbitals in the in-plane BC rings. Two aspects especially emphasized are (a) the HOMO-LUMO gap as function of n and (b) the role of different spin multiplicity., Phys. Lett. A, accepted

A crystalline form of LiBC is known which has been predicted to be superconducting, with a T-c comparable to that of MgB2. In both compounds, superconductivity is enhanced by the presence of two electronic bands, one of which is close to a dimensional crossover. Here, we take a quantum chemical approach, and investigate the structural and electronic properties of small clusters (LiBC)(n) (n = 1-4). With increasing cluster size, we find that several properties of crystalline LiBC evolve naturally from the corresponding properties of the clusters. In particular, one may recognize the origin of the solid bilayered structure, typical of magnesium diboride, and the character of the electronic a-band, arising from the overlap of the atomic orbitals in the in-plane BC rings. Two aspects especially emphasized are (a) the HOMO-LUMO gap as function of n and (b) the role of different spin multiplicity. (c) 2005 Elsevier B.V. All rights reserved.

We point out the incorrect derivation of the gap equation in X.-J. Chen and H. Q. Lin [Phys. Rev. B 69 (2004) 104518; cond-mat/0306680] within the interlayer tunneling (ILT) model for multilayered cuprates. There, the local structure in k-space of the ILT effective interaction has not been taken into due account when the ILT model is generalized to the case of n layers per unit cell. This is a specific characteristic of the ILT model that, apart from giving rise to a highly nontrivial k-dependence of the gap function, is known to enhance the critical temperature Tc in a natural way. As a consequence, we argue that Chen and Lin's results cannot be employed, in their present form, for a quantitative interpretation of the high-pressure dependence of Tc in Bi-2212, as is done by X.-J. Chen et al. [cond-mat/0408587]. Moreover, when the generalization of X.-J. Chen et al. [cond-mat/0408587] is applied to the case n=2, it fails to reproduce the original ILT gap equation. However, a more careful analysis of the ILT model for multilayered cuprates, taking into account the nonuniform hole distribution among inequivalent layers, has been earlier suggested to describe the observed pressure dependence of Tc in homologous series of high-Tc cuprates.

A simple derivation of the static Gross-Pitaevskii (GP) equation is given from an energy variational principle. The result is then generalized heuristically to the time-dependent GP form. With this as background, a number of different experimental areas explored very recently are reviewed, in each case contact being established between the measurements and the predictions of the GP equations. The various limitations of these equations as used on dilute inhomogeneous condensed Boson atomic gases are then summarized, reference also being made to the fact that there is no many-body wave function underlying the GP formulation. This then leads into a discussion of a recently proposed integral equation, derived by taking the Bogoliubov-de Gennes equation as starting point. Some limitations of the static GP differential equation are thereby removed, though it is a matter of further study to determine whether a correlated wave function exists as underpinning for the integral equation formulation., Comment: To appear in "Trends in Boson Research", edited by A. V. Ling (Nova Science, New York, ISBN 1594545219). Better quality figures available upon request

Within the time dependent Ginzburg-Landau theory, the effects of the superconducting fluctuations on the transport properties above the critical temperature are characterized by a non-zero imaginary part of the relaxation rate gamma of the order parameter. Here, we evaluate Im gamma for an anisotropic dispersion relation typical of the high-Tc cuprate superconductors (HTS), characterized by a proximity to an electronic topological transition (ETT). We find that Im gamma abruptly changes sign at the ETT as a function of doping, in agreement with the universal behavior of the HTS. We also find that an increase of the in-plane anisotropy, as is given by a non-zero value of the next-nearest to nearest hopping ratio r=t'/t, increases the value of | Im gamma | close to the ETT, as well as its singular behavior at low temperature, therefore enhancing the effect of superconducting fluctuations. Such a result is in qualitative agreement with the available data for the excess Hall conductivity for several cuprates and cuprate superlattices., to appear in Phys. Rev. B