The paper proposes a method for the synthesis of cam-integrated six-bar linkages (cammed-linkage) for tasks of exact rigid-body guidance. As a first step, a three degrees of freedom (d.o.f.) six-bar linkage is generated. Two cam-follower mechanisms are then synthesized in order to reduce the system's mobility and to obtain a single-input cammed-linkage. The final combined mechanism is able to rigidly guide the coupler through any number of precision configurations. A strategy for the optimization of the synthesis process, based on evolutionary theory, is also proposed. Dimensional and kinematic performance criteria and constraints are used to define a goal function, while a genetic algorithm is employed as optimum searching procedure. Two examples of motion generation problems are used to describe the proposed synthesis methodology and to prove, through kinematic simulations, its effectiveness. (c) 2006 Elsevier Ltd. All rights reserved.
Andreottola, G.
Cadonna, M.
Foladori, P.
Gatti, G.
Lorenzi, F.
Nardelli, P.
In most cases of winery effluent, the heavy metal content, especially zinc (Zn) and copper (Cu), does not meet the limits for the discharge as imposed by the most restrictive regulations at international level (0.4 mgCu/L and 1.0 mgZn/L in the Italian regulations). An alternative for the reduction of Cu and Zn is the on-site pre-treatment of wastewater at the winery in order to meet the limits for the discharge into the public sewerage. The purpose of this study is to evaluate the effectiveness of a pre-treatment based on chemical precipitation with chelating agents (TMT: 2,4,6-trimercaptotriazine), for the reduction of Cu and Zn from raw winery wastewater. The chemical precipitation was optimised at lab-scale through jar tests in order to evaluate the optimal dosages. An average dosage equal to 0.84 mL of TMT (15%) for 1 mg of Cu removed was estimated. Furthermore, the efficiency of the on-site chemical pre-treatment was investigated at pilot scale. The results confirmed the feasibility of using TMT treatment for the reduction of Cu and Zn in order to meet the limits for discharge into the sewerage. Contextually to the removal of heavy metals, the chemical pre-treatment allowed us to obtain the reduction of particulate COD and TSS. Finally, the costs for the operation and the management of the on-site pre-treatment were evaluated.
Gatti, G.
Bartoli, A.
Bertin, D.
Strolin-Benedetti, M.
Perucca, E.
The pharmacokinetics and pharmacodynamics of rolafagrel (FCE 22178), a novel thromboxane synthase inhibitor, were evaluated after single and multiple oral doses in eight healthy volunteers. After a single dose (400 mg), the drug was absorbed rapidly, peak plasma concentrations being attained within 2 h in all subjects. Elimination followed a biphasic course, with a rapid initial decline followed after 12-24 h by a late phase with a terminal half-life of about 10 h. About 100% of the administered dose could be recovered in urine within 72 h, mostly in conjugated form. During multiple dosing (400 mg t.i.d. for 5 days), steady-state conditions were approached on day 2 and AUC values over a dosing interval were similar to those observed after a single dose (72.3 vs 76.3 mu-g cntdot ml-1 cntdot h). Pharmacokinetic parameters calculated after multiple doses were similar to those observed after a single dose (C-max: 20.1 vs 18.2 mu-g cntdot ml-1; t-max: 1.2 vs 1.1 h; terminal half-life: 10.9 vs 11.4 h; CL: 85.2 vs 70.4 ml cntdot h-1 cntdot kg-1; V: 1.23 vs 1.24 l cntdot kg-1). Platelet generation of thromboxane B-2, the stable breakdown product of thromboxane A-2, was inhibited by 85% at a plasma rolafagrel concentration of about 4 mu-g cntdot ml-1, and only a small increase in inhibition was observed at higher concentrations.
Single-degree-of-freedom (SDOF) mechanical oscillators have been the most common type of generators used to harvest energy from mechanical vibrations. When the excitation is harmonic, optimal performance is achieved when the device is tuned so that its natural frequency coincides with the excitation frequency. In such a situation, the harvested energy is inversely proportional to the damping in the system, which is sought to be very low. However, very low damping means that there is a relatively long transient in the harvester response, both at the beginning and at the end of the excitation, which can have a considerable effect on the harvesting performance. This paper presents an investigation into the mechanical design of a linear resonant harvester to scavenge energy from time-limited harmonic excitations to determine an upper bound on the energy that can be harvested. It is shown that when the product of the number of excitation cycles and the harvester damping ratio is greater (less) than about 0.19, then more (less) energy can be harvested from the forced phase of vibration than from the free phase of vibration at the end of the period of excitation. The analytical expressions developed are validated numerically on a simple example and on a more practical example involving the harvesting of energy from trackside vibrations due to the passage of a train.
Cultrera, L.
Gatti, G.
Tazzioli, F.
Perrone, A.
Miglietta, P.
Ristoscu, C.
Orlanducci, S.
Fiori, A.
Advanced high brightness radio frequency (RF) gun injectors require photocathodes with a fast response, high quantum efficiency (QE) and good surface uniformity. Metal films deposited by various techniques on the gun back wall could satisfy these requirements. A new deposition technique has been recently proposed, i.e. pulsed laser ablation. Several Mg samples have been deposited by this technique: the emission performance and morphological changes induced on the cathode surface during laser activation are compared and discussed. (C) 2007 Elsevier B.V. All rights reserved.
Maisonnier, D.
Amelotti, F.
Chiasera, A.
Gaggini, P.
Damiani, C.
Degli Esposti, L.
Gatti, G.
Castillo, E.
Caravati, D.
Farfalletti-Casali, F.
Gritzmann, P.
Ruiz, E.
The remote replacement of blanket segments inside the vacuum vessel of a fusion reactor is probably the most complex task from the maintenance standpoint. Its success will rely on the definition of appropriate handling concepts and equipment, but also on a ldquomaintenance friendlyrdquo reactor layout and blanket design. The key difficulty is the lack of rigidity of the segments which results in considerable deformations since they cannot be gripped above their centre of gravity. These deformations may be up to five times greater than the assembly clearance and one order of magnitude larger than the required positioning accuracy. Experimental activities have been undertaken to select appropriate handling devices and procedures, to assess the design of the components handled, and to review specific technical issues such as kinematics and dynamics performance, trajectory planning and control and sensors requirement for the handling devices. Work was performed in the Robertino facility where two handling concepts have been tested at a 1/3 scale
Bacci, A.
Broggi, F.
DeMartinis, C.
Giove, D.
Maroli, C.
Petrillo, V.
Rossi, A. R.
Serafini, L.
Tomassini, P.
Cultrera, L.
Di Pirro, G.
Ferrario, M.
Filippetto, D.
Gatti, G.
Pace, E.
Vaccarezza, C.
Vicario, C.
Bosi, F.
Giulietti, D.
Gizzi, L. A.
Oliva, P.
The PLasma Acceleration and MONochromatic X-ray generation (PLASMONX) project foresees the installation at LNF of a 0.3 PW (6 J, 20 fs pulse) Ti:Sa laser system, named Frascati Laser for Acceleration and Multidisciplinary Experiments (FLAME), to operate in close connection with the existent SPARC electron photo-injector, allowing for advanced laser/e-beam interaction experiments. Among the foreseen scientific activities, a Thomson scattering experiment between the SPARC electron bunch and the high power laser will be performed. At the present time the linac has been tested and the electron beam characterized up to the maximum operating energy (150 MeV). The beam lines transporting the beam to the interaction chamber with the laser have been designed. The electron final focusing system, featuring a quadrupole triplet and large radius solenoid magnet (ensuring an e-beam waist of 5-10 mu m) as well as the whole interaction chamber layout has been defined. The optical transfer line issues: transport up to the interaction; tight focusing; diagnostics and fine positioning; have been solved within the final design. The construction of the building hosting the laser has been completed: delivering and installation of the laser, as much of the beam lines elements will take place in the next months. (C) 2009 Elsevier B.V. All rights reserved.
We propose a decoherence protected protocol for sending single photon quantum states through depolarizing channels. This protocol is implemented via an approximate quantum adder engineered through spontaneous parametric down converters, and shows higher success probability than distilled quantum teleportation protocols for distances below a threshold depending on the properties of the channel.
Cianchi, A.
Anania, M. P.
Bellaveglia, M.
Bisesto, F.
Castellano, M.
Chiadroni, E.
Di Giovenale, D.
Di Pirro, G.
Ferrario, M.
Gatti, G.
Mostacci, A.
Pompili, R.
Shpakov, V.
Stella, A.
Villa, F.
Advanced diagnostic tools for high brightness electron beams are mandatory for the proper optimization of plasma-based accelerators. The accurate measurement of beam parameters at the exit of the plasma channel plays a crucial role in the fine tuning of the plasma accelerator. Electron beam diagnostics will be reviewed with emphasis on emittance measurement, which is particularly complex due to large energy spread and strong focusing of the emerging beams.
Labate, L.
Anelli, F.
Bacci, A.
Batani, D.
Bellaveglia, M.
Benedetti, C.
Benocci, R.
Cacciotti, L.
Cecchetti, C. A.
Ciricosta, O.
Clozza, A.
Cultrera, L.
Di Pirro, G.
Drenska, N.
Faccini, R.
Ferrario, M.
Filippetto, D.
Gallo, S.
Fioravanti, S.
Gamucci, A.
Gatti, G.
Ghigo, A.
Giulietti, A.
Giulietti, D.
Koester, P.
Levato, T.
Lollo, V.
Pace, E.
Pathak, N.
Rossi, A.
Serafini, L.
Turchetti, G.
Vaccarezza, C.
Valente, P.
Vicario, C.
Gizzi, L. A.
A 250-TW laser system (FLAME - Frascati laser for acceleration and multidisciplinary experiments) is now in its commissioning phase in a new laboratory at LNF-INFN in the framework of the PLASMONX (Plasma acceleration and monochromatic X-ray generation) project. The laser will deliver25fs duration pulses with an energy up to 6J, at a 10Hz repetition rate. An ad hoc target area has also been designed and is currently being set up, allowing the first test experiments of electron laser wakefield acceleration to be carried out over the next few months in a safe, radiation-protected environment. An overview of the main features of the laser system and target area is given, along with a survey of the design and set-up of the self-injection test experiment, which is expected to reach the production of sub-GeV electron bunches.
Creat membership
Sweep WeChat yards
