124 research outputs found
The Edna McConnell Clark Foundation's Tropical Disease Research Program: A 25-Year Retrospective Review 1976-1999
Documents and details the foundation's commitment to the program from its inception, and provides an analysis of its successes until the completion of the program in 1999
The Italian contribution to the construction of the linac for the European spallation source
AbstractThe European spallation source (ESS) uses a linear accelerator (linac) to deliver the high intensity proton beam to the target station for producing intense beams of neutrons. At the exit of the linac, the proton beam will have 2 GeV energy and 62.5 mA current. The construction of an accelerator with the contribution of different laboratories is not a new concept but so far the laboratories were controlled by the same government (e.g. in USA and Japan) or they delivered components for an intergovernmental institution like CERN. The European Spallation Source is a research facility that gathers 40 active in-kind (IK) contributors from 13 States, even outside the European Union, so its construction is not only a technical and scientific challenge, but also an economic, political and social experiment. The case of the Italian contribution is interesting because of the structure of Italian industrial ecosystem, mostly based on small and medium-sized enterprises (SME), which may be unsuitable for the case of a research infrastructure which construction requires a high level of R&D investments. Conversely, the well-known flexibility of SME to adapt to the requirements have balanced the weakness and the results are satisfactory. Following the overview of the Linac design, the paper will focus on the key issues of the Italian contribution, the state of the project (73% completion up to now) along with the point of view of the ESS management and the lesson learnt; the major outcomes for the economy and society will complete the discussion
Rapid One-Step Fabrication of Graphene Oxide-Decorated Polycaprolactone Three-Dimensional Templates for Water Treatment
Coating of flexible substrates is crucial to prepare versatile, multifunctional materials. However, exploration of effective fabrication approaches is still a challenging issue, because the pathways generally proposed require time-consuming, multistep protocols. Here, we developed a one-pot process for decorating either pearl necklace-like or fibrous fluffy-like structures of polycaprolactone (PCL) with graphene oxide (GO) skin. PCL solutions were dry jet-wet electrosprayed or electrospun into a stirred liquid collector constituted by ethanol-containing GO nanoparticles. The stirred liquid collector enables the formation of 3D-structures, whose microarchitecture can be designed by controlling the rheological behavior of PCL solutions. Two molecular weights of PCL were used (45 or 80 kDa) with ensuing different viscosity, which determines the prevalent formation of beads or fibers. The presence of GO in the coagulation bath allows the polymeric structures to be rapidly wrapped by those nanoparticles. Graphenic coating endows these materials with the intriguing peculiarities of GO: PCL/GO nanocomposites displayed increments of elastic modulus ranging from 1250% (beads) to 3300% (fibers) with respect to the neat matrices and a change from hydrophobic to amphiphilic character. A potential application of such devices in water treatment was assessed in phenol removal. The results pointed out that PCL/GO scaffolds retain the same sorption capacity of GO nanoparticles, while bringing several advantages in terms of handling, robustness, and recyclability. The ease of control of the process, as well as its fastness and cost-effectiveness could open a wide range of scenarios, including sensors, energy, catalysis, biomedicine
Installation of ECR2 at LNS and Preliminary tests
The source ECR2 has been built in 1998 by Pantechnik, according to the design suggested by LNS Ion Source Group. This design entails some improvements with respect to a standard CAPRICE-type source: a) the magnetic field (up to 1.6 T axial, 1.1 T radial) allows to operate the source at 14 GHz in High B mode and at 18 GHz; b) two frequency heating can be used; c) an aluminum made plasma chamber is used in place of the stainless steel one. The main features of ECR2 along with a review of the preliminary tests will be outlined. Typical currents for fully stripped nitrogen are about 25 emA; for the heaviest ions, 1 emA of Kr28+ and 10 emA of Ta27+ have been measured. The installation at LNS has been completed recently and the details will be given
Validity and reliability of an inertial sensor device for specific running patterns in soccer
Electronic performance tracking devices are largely employed in team sports to monitor performance and improve training. To date, global positioning system (GPS) based devices are those mainly used in soccer training. The aim of this study was to analyse the validity and reliability of the inertial sensor device (ISD) in monitoring distance and speed in a soccer-specific circuit and how their performance compare to a GPS system. 44 young male soccer players (age: 14.9 ± 1.1, range 9– 16, years, height: 1.65 ± 0.10 m, body mass: 56.3 ± 8.9 kg) playing in a non-professional soccer team in Italy, participated in the study. We assessed the players trough a soccer running sport-specific circuit. An ISD and a GPS were used to assess distance and speed. Data was compared to a video reference system, and the difference were quantified by means of the root mean square error (RMSE). Significant differences were found for both GPS and ISD devices for distance and speed. However, lower error for distance (dRMSE 2.23 ± 1.01 m and 5.75 ± 1.50 m, respectively) and speed (sRMSE 0.588 ± 0.152 m*s–1 and 1.30 ± 0.422 m*s–1, respectively) were attained by the ISD compared to the GPS. Overall, our results revealed a statistically significant difference between systems in data monitoring for either distance and speed. However, results of this study showed that a smaller error was obtained with the ISD than the GPS device. Despite caution is warranted within the interpreta-tion of these results, we observed a better practical applicability of the ISD due to its small size, lower cost and the possibility to use the device indoor
Application of Ferroelectric Cathodes to Enhance the Ion Yield in the Caesar Source at LNS
With increasing RF power the electron concentration in the plasma of ECR ion sources is decreasing in comparison to the ion concentration, so that the plasma is charging up positively. Direct injection of electrons into the ECR plasma can increase the electron charge density and the ion current yield. We have used ferroelectric cathodes to inject electrons into the Argon plasma of the CAESAR ion source at INFN-LNS (Catania, Italy). The cathode was placed at about 10 cm from the hot plasma and a bipolar high voltage pulse of 1.6 kV was used to trigger the electron emission. No additional acceleration has been provided. The use of the ferroelectric cathode leads to an increase of about 30% of the Ar8+ intensity, which has been monitored during the test. In addition, magneto-hydrodynamic instabilities in the ECR source were damped during and after electron injection
Production of intense highly charged ion beams with SERSE
The source SERSE is operational at LNS since June 1998 and many improvements have been carried out in this period. The frequency has been increased from 14.5 GHz to 18 GHz and the use of two frequency heating has given positive results. Metallic ion production has been tested by means of a high temperature oven and the preliminary results are described. Tests of magnetic field scaling and frequency scaling have confirmed the results of previous tests with SC-ECRIS at lower frequency and seems to suggest that the upgrading of the source to higher frequency may be considered
Summary of the performances of the superconducting electron cyclotron resonance ion source at 14 GHz
This article deals with the most recent performance of the superconducting electron cyclotron resonance ion source (SERSE) working at 14 GHz with high magnetic fields after the required conditioning and optimization of several operating parameters. SERSE has now achieved an outstanding level of performance in delivering highly charged ion beams in argon and oxygen gases: the results obtained while operating in a stainless steel chamber and with an aluminum liner are shown and discussed
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