We present the measurement of negative ion drift velocities and mobilities for innovative particle tracking detectors using gas mixtures based on SF6. This gas has recently received attention in the ...context of directional Dark Matter searches, thanks to its high Fluorine content, reduced diffusion and multiple species of charge carriers, which allow for full detector fiducialization. Our measurements, performed with a 5 cm drift distance Negative Ion Time Projection Chamber, show the possibility of negative ion operation in pure SF6 between 75 and 150 Torr with triple thin GEM amplification, confirming the attractive potentialities of this gas. Above all, our results with the mixture He:CF4:SF6 360:240:10 Torr demonstrate for the first time the feasibility of SF6− negative ion drift and gas gain in He at nearly atmospheric pressure, opening very interesting prospects for the next generation of directional Dark Matter detectors.
The solution of the problem of heat exhaust has been pointed out as one of the main challenge towards the realization of magnetic confinement fusion. In the last years, two concepts have been ...proposed in alternative to the conventional divertor solution adopted for ITER: modification of the magnetic topology in the divertor region and liquid metal as plasma facing component. The role of the Divertor Tokamak Test facility (DTT) in the power exhaust implementation strategy is discussed. The evolution of the project, since the original proposal in 2015 to the present design, is shown. The DTT facility is well integrated in the European strategy and the final decision on the divertor configuration will be made, within 2022-23, on the basis of the indication of the Power Exhaust Group constituted by the EUROfusion Consortium. Finally, the main milestones and the timeline of the project are illustrated.
Power exhaust is a key mission in the roadmap to the realization of a future fusion reactor. Among the different solutions, the use of liquid metals as plasma facing materials are of interest due to ...their potential increased lifetime. Several liquid metal limiters have been successfully tested in the Frascati Tokamak Upgrade over the last 10 years. Liquid materials such as lithium and tin have been investigated using capillary porous systems (CPSs), and their impact on plasma performance has been explored. From such experience, a liquid metal divertor (LMD) concept design, CPS-based, is here proposed. Tin has been preferred as plasma facing material. The proposed LMD would operate, in low evaporative regime, with matching heat exhausting capabilities to those of the baseline ITER-like divertor. Continuous refilling of the CPS is guaranteed with a reservoir at the back of the unit, where the metal is kept liquid through a gas heating circuit. The study has been carried out using ANSYS and the thermal results will be shown. All the design choices are compatible with the current materials and the constraints adopted for the DEMO W divertor. Using such configuration, thermal loads up to 20 MW/m
2
are exhausted while keeping the surface temperature below 1250 °C. The design foresees values of pressure, temperature and flow rate of the water coolant in the same range expected for the W DEMO divertor, thus facilitating the integration of such solution in the current cassette design. Technological and practical aspects are addressed, i.e. tin corrosion and CPS wettability. Possible solutions to prevent tin corrosion, and its compatibility with structural materials, will be outlined.
The search for a novel technology, which is able to detect and reconstruct nuclear recoil events in the keV energy range, has become increasingly important now that vast regions of high mass ...weakly-interacting-massive-particle-like dark matter candidates have been excluded. Gaseous time projection chambers (TPC) with optical readout are very promising candidates combining the complete event information provided by the TPC technique with the high sensitivity and granularity of the latest generation light sensors. A TPC with an amplification at the anode, obtained with gas electron multipliers (GEMs), was tested at the Laboratori Nazionali di Frascati. Photons and neutrons from radioactive sources were employed to induce recoiling nuclei and electrons with kinetic energy in the range 1-100 keV. A He-CF4 (60/40) gas mixture was used at atmospheric pressure and the light produced during the multiplication in the GEM channels was acquired by a high-position resolution and low-noise complementary metal-oxide semiconductor camera and a photomultiplier. A multi-stage pattern recognition algorithm based on an advanced clustering technique is presented here. A number of cluster-shaped observables are used to identify nuclear recoils induced by neutrons, which originated from a AmBe source against x-ray 55Fe photoelectrons. An efficiency of 18% to detect nuclear recoils with an energy of about 6 keV is reached, while suppressing 96% of the 55Fe photoelectrons, making this optical read-out gas TPC a very promising candidate for future investigations of ultra-rare events such as directional direct dark matter searches.
•Design review of the Italian Divertor Tokamak Test facility: engineering aspects.•Rationale for design choices and main differences from the original proposal.•Main goal of DTT: explore and qualify ...alternative power exhaust solutions for DEMO.•Edge conditions similar to DEMO in terms of dimensionless parameters.•Test of alternative divertor solutions in integrated scenarios.
This paper presents the engineering aspects of the design review of the Italian DTT (Divertor Tokamak Test facility), illustrating the rationale for the design choices and focusing on the main differences with respect to the original proposal.
Purpose
Antibiotic-loaded bone cement has been widely used for the treatment of infected knee replacement, but its routine use in primary TKA remains controversial. The aim of this systematic review ...was to analyze the literature about the antimicrobial efficacy and safety of antibiotic-loaded bone cement for its prophylactic use in primary TKA.
Methods
A detailed and systematic search of the Pubmed, Medline, Cochrane Reviews and Google Scholar databases had been performed using the keyword “total knee arthroplasty” “total knee replacement” “total knee prosthesis” and “antibiotic-loaded bone cement” with no limit regarding the year of publication. We used modified Coleman scoring methodology (mCMS) to identify scientifically sound articles in a reproducible format. The review was limited to the English-language articles.
Results
Six articles met inclusion criteria. In total, 6318 arthroplasties were included in our study. 3217 of these arthroplasties received antibiotic-loaded bone cement and 3101 arthroplasties served as the control. There was no statistical difference between the two groups in terms of the incidence of deep or superficial surgical site infection. The average mCMS score was 67.6, indicating good methodological quality in the included studies.
Conclusions
Present review did not reveal any significant difference in terms of rate of deep or superficial surgical site infection in patients receiving antibiotic-loaded bone cement compared with the control (plain bone cement) during primary TKA. The clinical relevance of this study was that the use of antibiotic-loaded bone cement did not significantly reduce the risk of infection in primary TKA.
Level of evidence
III.
Liquid tin limiter for FTU tokamak Vertkov, A.; Lyublinski, I.; Zharkov, M. ...
Fusion engineering and design,
04/2017, Letnik:
117
Journal Article
Recenzirano
•First steady state operating liquid tin limiter TLL is under study on FTU tokamak.•The cooling system with water spray coolant for TLL has been developed and tested.•High corrosion resistance of W ...and Mo in molten Sn confirmed up to 1000°C.•Wetting process with Sn has been developed for Mo and W.
The liquid Sn in a matrix of Capillary Porous System (CPS) has a high potential as plasma facing material in steady state operating fusion reactor owing to its physicochemical properties. However, up to now it has no experimental confirmation in tokamak conditions. First steady state operating limiter based on the CPS with liquid Sn installed on FTU tokamak and its experimental study is in progress. Several aspects of the design, structural materials and operation parameters of limiter based on tungsten CPS with liquid Sn are considered. Results of investigation of corrosion resistance of Mo and W in Sn and their wetting process are presented.
The heat removal for limiter steady state operation is provided by evaporation of flowing gaswater spray. The effectiveness of such heat removal system is confirmed in modelling tests with power flux up to 5MW/m2.
The DTT facility is designed to study, within the European Fusion Road Map, the completely integrated (physics-technology and bulk-edge) power exhaust problems. The scientific program is ...characterized by the tight balance between clear guidelines and the “flexibility” to tackle all the present scientific questions as well as the ideas possibly arising along the years of its operative life; in particular, it will be ready to answer to the necessities arising from both ITER operation and/or DEMO design. The paper discusses the guideline of DTT operations program to be carried out during its operative life, planned in about thirty years.
The third International Symposium on Lithium Application for Fusion Device (ISLA-2013) was held on 9-11 October 2013 at ENEA Frascati Centre with growing participation and interest from the community ...working on more general aspect of liquid metal research for fusion energy development. ISLA-2013 has been confirmed to be the largest and the most important meeting dedicated to liquid metal application for the magnetic fusion research. Overall, 45 presentation plus 5 posters were given, representing 28 institutions from 11 countries. The latest experimental results from nine magnetic fusion devices were presented in 16 presentations from NSTX (PPPL, USA), FTU (ENEA, Italy), T-11M (Trinity, RF), T-10 (Kurchatov Institute, RF), TJ-II (CIEMAT, Spain), EAST(ASIPP, China), HT-7 (ASIPP, China), RFX (Padova, Italy), KTM (NNC RK, Kazakhstan). Sessions were devoted to the following: (I) lithium in magnetic confinement experiments (facility overviews), (II) lithium in magnetic confinement experiments (topical issues), (III) special session on liquid lithium technology, (IV) lithium laboratory test stands, (V) Lithium theory/modelling/comments, (VI) innovative lithium applications and (VII) special Session on lithium-safety and lithium handling. There was a wide participation from the fusion technology communities, including IFMIF and TBM communities providing productive exchange with the physics oriented magnetic confinement liquid metal research groups. This international workshop will continue on a biennial basis (alternating with the Plasma-Surface Interactions (PSI) Conference) and the next workshop will be held at CIEMAT, Madrid, Spain, in 2015.
In order to prevent the overheating of the liquid Li surface and the consequent Li evaporation for T>500°C, an advanced version of the liquid lithium limiter has been realized and installed on FTU. ...This new system, named Cooled Lithium Limiter (CLL), has been optimized to demonstrate the lithium limiter capability to sustain thermal loads as high as 10MW/m2 with up to 5s of plasma pulse duration. The CLL operates with an actively cooled system with water circulation at the temperature of about 200°C, for heating lithium up to the melting point and for the heat removal during the plasma discharges. To characterize CLL during discharges, a fast infrared camera and the spectroscopic signals from Li and D atom emission have been used. The experiments analyzed so far and simulated by ANSYS code, point out that heat loads as high as 2MW/m2 for 1.5s have been withstood without problems.
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