Search

Various DC tests performed recently with full-size 60 kA HTS cable prototypes in the EDIPO test facility demonstrated that proposed design of HTS strand at Swiss Plasma Center (SPC) – stack of HTS tapes twisted and soldered between two copper profiles – is applicable for high-current fusion cables, but improvement of the strand mechanical properties against the cyclic loading is still needed. Based on experimentally obtained correlation between the performances of cable prototypes at different operating conditions, further investigation of cyclic transverse load on the strand performance was performed at 77 K. Aiming to obtain a strand design able to withstand a continuous cyclic load operation of some thousand cycles, influence of the strand geometry and tape's manufacturer has been studied. Cyclic load has been applied up to 1000 cycles for straight and bent samples at the load amplitudes up to 4 MPa. Based on the obtained data, next design of HTS cable prototype will be discussed.

The present study aims to reduce the outer radius of the central solenoid (CS) with respect to its nominal size specified by EUROfusion for a maintained CS magnetic flux. A reduced outer CS radius would allow the reduction of the overall size and cost of the DEMO magnet system. The proposed outline design of the winding pack for the CS1 module is based on layer winding. To achieve the same magnetic flux in a CS coil of significantly reduced outer radius the peak magnetic field at the CS conductors needs to be substantially increased. The use of high-temperature superconductors is therefore envisaged in the highest field sections of the CS coil. It is planned to use react & wind Nb3Sn conductors for intermediate field sections and NbTi at the lowest fields. In order to make a most economic use of the superconductors the proposed winding pack design considers a superconductor grading.

Despite numerous spectacular archaeological discoveries worldwide related to melting ice patches and the emerging field of glacial archaeology, governing processes related to ice patch development during the Holocene and their sensitivity to climate change are still largely unexplored. Here we present new results from an extensive 6-year (2009–2015) field experiment at the Juvfonne ice patch in Jotunheimen in central southern Norway. Our results show that the ice patch has existed continuously since the late Mesolithic period. Organic-rich layers and carbonaceous aerosols embedded in clear ice show ages spanning from modern at the surface to ca. 7600 cal years BP at the bottom. This is the oldest dating of ice in mainland Norway. The expanding ice patch covered moss mats appearing along the margin of Juvfonne about 2000 years ago. During the study period, the mass balance record showed a strong negative balance, and the annual balance is highly asymmetric over short distances. Snow accumulation is poorly correlated with estimated winter precipitation, and single storm events may contribute significantly to the total winter balance. Snow accumulation is approx. 20 % higher in the frontal area compared to the upper central part of the ice patch. There is sufficient meltwater to bring the permeable snowpack to an isothermal state within a few weeks in early summer. Below the seasonal snowpack, ice temperatures are between −2 and −4 °C. Juvfonne has clear ice stratification of isochronic origin.

In the last 10-15 years, the most common strategy in the development of High Temperature Superconducting (HTS) cable for magnets has been to imitate Low Temperature Superconducting (LTS) cable designs. However, requirements for LTS materials are not valid for HTS materials, which are extremely stable. For example, non-twisted multifilamentary Bi-2223 tapes have been successfully used in several magnets. This paper review stability and analyse inductance and AC losses in non-twisted stack of HTS tapes. Numerical calculations show that twisting has negligible effect on inductance variations in a stack of tapes. Regarding AC losses, any magnet built with coated conductors have larger losses than LTS ones, because of the aspect ratio and large width of the tape. If a wide tape is replaced by a non-twisted stack of narrow tapes, losses and residual magnetisation could be reduced. In contrast with multifilamentary wires, twisting a stack of tapes reduces losses only marginally. Therefore, cables composed of non-twisted stack could be designed to have losses comparable to the one of twisted stack concepts. Few examples of large cables for fusion applications are discussed. Designs based on non-twisted stacks can be simpler, more robust and cost effective than twisted ones., Comment: 20 pages, 10 figures, submitted to Cryogenics

Alpine glaciers are valuable archives for the reconstruction of human impact on the environment. Besides dating purposes, measurement of radiocarbon (14C) content provides a powerful tool for long-term source apportionment studies on the carbonaceous aerosols incorporated in ice cores. In this work, we present an extraction system for14C analyses of dissolved organic carbon (DOC) in ice cores. The setup can process ice samples of up to 350 g mass and offers ultra-clean working conditions for all extraction steps. A photo-oxidation method is applied by means of external UV irradiation of the sample. For an irradiation time of 30 min with catalyzation by addition of Fe2+and H2O2, we achieve an efficiency of 96 ± 6% on average. Inert gas working conditions and stringent decontamination procedures enable a low overall blank of 1.9 ± 1.6 μg C with a F14C value of 0.68 ± 0.13. This makes it possible to analyze the DOC in ice samples with a carbon content of as low as 25 μg C kg−1ice. For a first validation, the new method was applied to ice core samples from the Swiss Alps. The average DOC concentration and F14C values for the Fiescherhorn ice core samples show good agreement with previously reported data for the investigated period of 1925–1936 AD.

The next generation magnetic spectrometer in space, AMS-100, is designed to have a geometrical acceptance of $100\,\mathrm{m}^2\,\mathrm{sr}$ and to be operated for at least ten years at the Sun-Earth Lagrange Point 2. Compared to existing experiments, it will improve the sensitivity for the observation of new phenomena in cosmic rays, and in particular in cosmic antimatter, by at least a factor of 1000. The magnet design is based on high temperature superconductor tapes, which allow the construction of a thin solenoid with a homogeneous magnetic field of 1 Tesla inside. The inner volume is instrumented with a silicon tracker reaching a maximum detectable rigidity of 100 TV and a calorimeter system that is 70 radiation lengths deep, equivalent to four nuclear interaction lengths, which extends the energy reach for cosmic-ray nuclei up to the PeV scale, i.e. beyond the cosmic-ray knee. Covering most of the sky continuously, AMS-100 will detect high-energy gamma rays in the calorimeter system and by pair conversion in the thin solenoid, reconstructed with excellent angular resolution in the silicon tracker., Comment: 26 pages, 15 figures, to be submitted to Nuclear Instruments and Methods in Physics Research Section A. Corresponding author: Stefan Schael

La piccola lastra venne rinvenuta nel corso degli scavi di emergenza del 1999-2000 nell’area di S. Lazzaro (Reggio Emilia) nella necropoli orientale di Regium Lepidi, reimpiegata come letto funerario nella tomba 377, databile al II-III sec. d.C.

Scheda di catalogo di una stele a pseudoedicola rinvenuta nel corso degli scavi di emergenza del 1999-2000 nell’area di S. Lazzaro (Reggio Emilia) nella necropoli orientale di Regium Lepidi. L’epigrafe venne invenuta in situ e menziona gli intestatari del monumento, Lucius Latinius Luci fiulius e Caecia Publi filia, padre e madre di Lucius Latinius Stabilio.

Scheda di due epigrafi funerarie inedite provenienti dagli scavi di emergenza del 1999-2000 nell’area di S. Lazzaro (Reggio Emilia) nella necropoli orientale di Regium Lepidi. Le due epigrafi provengono da due sepolture differenti (tt. 103 e t. 105) e menzionano lo stesso individuo.

La scheda presenta una epigrafe inedita rinvenuta nel corso degli scavi di emergenza del 1999-2000 nell’area di S. Lazzaro (Reggio Emilia) nella necropoli orientale di Regium Lepidi. L’epigrafe venne invenuta in situ (t. 191), spezzata in due parti.

Scheda di catalogo della lastra sepolcrale del vir clarissimus Rusticus, morto il 24 novembre del 526 d.C. La pietra venne rinvenuta negli anni Cinquanta del Novecento nel corso di lavori di ristrutturazione a Reggio Emilia, via Emilia all’Angelo 1.

La scheda di catalogo presenta una stele funeraria di età imperiale rinvenuta reimpiegata come copertura di una tomba longobarda durante gli scavi precedenti ai lavori di restauro di Palazzo Mongardini, a Reggio Emilia, nel 2010. La stele menziona un decurio civitatis Regiensium.

Analisi e inquadramento storico archeologico di un miliario iscritto rinvenuto a S. Faustino di Rubiera nel 1988.

Analisi e inquadramento storico archeologico dei resti di un ponte di attraversamento del fiume Secchia in corrispondenza di Marzaglia e dell'epigrafe commemorativa del suo rifacimento (CIL XI 826).

Analisi di un cippo con iscrizione dedicatoria al dio Terminus. L'iscrizione (CIL XI, 956), proveniente da Reggio Emilia, era documentata dal 1708 ed è ora conservata nella Sala della Reggio Romana dei Musei Civici di Reggio Emilia.

Cardiovascular disease is a leading cause of death in women, nevertheless it is often underestimated in female patients without overt risk factors. The chronic infection by Human Immunodeficiency Virus (HIV) is clearly associated, along with the use of certain antiretroviral drugs and traditional risk factors, with an increased risk of cardiovascular diseases. The aim of this manuscript is to review the epidemiology, risk factors, pathogenesis, diagnostic approach, primary and secondary prevention strategies of cardiovascular disease in HIV-negative and HIV-positive female subjects. The ultimate goal is to promote knowledge and development of specific and appropriate clinical interventions and guidelines in this group of high-risk patients, mostly in view of the expected growth of ageing females with HIV.

A 50 kA REBCO conductor based on the Twisted-Stacked-Tape-cable concept is being developed at Swiss Plasma Center (SPC) for EU-DEMO central solenoid. The conductor contains 12 strands and each one is made of twisted REBCO tape stack soldered in round copper profile with rectangular slot. In this paper, first it is verified if the strands could be modelled as monolithic elements for quench simulation, which means instantaneous heat propagation within the domain and homogeneous current density, by studying the influence of the inter-tape and stack-profile resistance on their heat and current transfer. Then a local disturbance induced quench on the 50 kA REBCO conductor is studied in detail considering various inter-strand electrical resistance.

Endometrial polyps are a common condition. The risk of malignancy has often led to an overtreatment with high health care costs and huge psychological distress.We conducted a systematic review and a meta-analysis in order to estimate the prevalence of premalignant and malignant lesions in women undergoing hysteroscopic polypectomy.We developed the search using PubMed/MEDLINE and EMBASE databases to identify papers published between 2000- January 2019. The research strategy used on Pubmed was: ("polyps" (MESH) OR "endometrial polyp*") AND ("malignancy" OR "cancer" OR "histopathology" OR "hysteroscopy" OR "ultrasound", OR "sonohysterography"). The same search was modified for EMBASE.We included all observational retrospective and prospective studies and studies were selected for the review if they met following inclusion criteria: pre-operative diagnosis of benign-looking endometrial polyps at ultrasound examination or at hysteroscopy, excision of endometrial polyps via surgical hysteroscopy, histopathological diagnosis of benign polyps, or hyperplasia without atypia, or premalignancy (atypical hyperplasia) or malignancy (endometrial cancer). Moreover, studies were included if number or percentage of subjects with and without malignancy was provided and if they reported data about menopausal and/or bleeding status. We excluded data presented exclusively as abstracts in national and international meetings, or case report or review articles that did not include original data and papers published in other than English language. Our primary outcome was the prevalence of endometrial premalignant or malignant polyps in the total series, among premenopausal and postmenopausal women and among women with or without abnormal bleeding and then in subgroup analysis according to study design, diagnostic method, study region and calendar year of publication.A total of 51 studies reporting data on 35,345 women were included in this review. The prevalence of malignant polyps was 2.73% (95% CI 2.57-2.91) with very high heterogeneity among studies. The rates were lower for premenopausal women (1.12%) than post-menopausal ones (4.93%) and the difference was statistically significant (chi-square = 397.21. p .0001). The risk of malignancy was higher among symptomatic (5.14%) than asymptomatic ones (1.89%) (chi-square = 133.13 p .001). We observed higher rate of malignant polyps in prospective studies. In the meta-analysis selecting 10 prospective studies the random pooled estimate was 5.88 (95% CI: 4.06-7.97) with heterogeneity among studies (heterogeneity chi square = 17.55 P = .025) whereas in retrospective studies the random pooled estimate was 2.94 (95% CI:2.24-3.71) with high heterogeneity among studies (P .001). This finding can be due to more strict diagnostic criteria in prospective studies.Symptomatic vaginal bleeding and postmenopausal status in women with endometrial polyps increased the risk of malignancy. This finding could be an useful evidence to select patients who need to undergo hysteroscopic resection of endometrial polyps and women to whom, instead, an expectant management can be offer.

The performance of ITER toroidal field (TF) conductors still have a significant margin for improvement because the effective strain between -0.62% and -0.95% limits the strands' critical current between 15% and 45% of the maximum achievable. Prototype Nb3Sn cable-in-conduit conductors have been designed, manufactured and tested in the frame of the EUROfusion DEMO activities. In these conductors the effective strain has shown a clear improvement with respect to the ITER conductors, reaching values between -0.55% and -0.28%, resulting in a strand critical current which is two to three times higher than in ITER conductors. In terms of the amount of Nb3Sn strand required for the construction of the DEMO TF magnet system, such improvement may lead to a reduction of at least a factor of two with respect to a similar magnet built with ITER type conductors; a further saving of Nb3Sn is possible if graded conductors/windings are employed. In the best case the DEMO TF magnet could require fewer Nb3Sn strands than the ITER one, despite the larger size of DEMO. Moreover high performance conductors could be operated at higher fields than ITER TF conductors, enabling the construction of low cost, compact, high field tokamaks. © 2018 IOP Publishing Ltd.

The ReactW –0.30%. After the baseline of the DEMO device was updated in 2015, the new requirements led to an updated conductor design, for 63 kA at 12.2 T. The manufacturing experience of the first prototype, named RW1, is exploited in a second short-length prototype conductor, named RW2, assembled and tested in 2017: The conductor aspect ratio is reduced, and the segregated copper wires are replaced by a solid block of mixed matrix stabilizer. Although designed for the TF coils, with dc operation, the moderate ac loss of the flat cable makes the RW2 a good candidate also for the central solenoid conductor. The Nb3Sn strand for RW2 is supplied by WST (PRC), and the flat cable is made at TRATOS (Italy). The rationale of the design, the conductor manufacture, the sample assembly, and the test results in SULTAN are reported.

This paper reports on novel separation methods developed for the direct determination of 14C in organic carbon (OC) and elemental carbon (EC), two sub-fractions of total carbon (TC) of atmospheric air particulate matter. Until recently, separation of OC and EC has been performed off-line by manual and time-consuming techniques that relied on the collection of massive CO2 fractions. We present here two on-line hyphenated techniques between a Sunset OC/EC analyzer and a MICADAS (MIni radioCArbon DAting System) accelerator mass spectrometer (AMS) equipped with a gas ion source. The first implementation facilitates the direct measurement in the low sample size range (

The tilted head race track coils of the EDIPO test facility are wound with cable-in-conduit conductors made by high current density Nb3Sn strands, Jc = 2400 A/mm2 at 12 T – 4.2 K. Since the commissioning of the coils, frequent voltage spikes were observed at the quench detection taps during the low current range of operation, completely disappearing above 2 T. The large amplitude of some spikes triggered the quench detection system: the parameters for protection (voltage thresholds and validation time) had to be modified for the voltage pairs monitoring the windings. The occurrence of partial flux jumps in the high current density strands is known from former characterization. The fast data acquisition of the quench detection system, with 800 Hz sampling frequency, allows investigation of the dynamics and propagation of the voltage spikes in the various layers of the winding. From the collected data of several runs of operation, statistics of amplitude, initial location, propagation and reproducibility were drawn, looking also for correlation with the operation history, e.g. first cooldown, ramp up vs. ramp down, ramp rate, etc. The energy released by the flux jumps is conservatively estimated by the time integration of the voltage spikes and discussed in terms of energy margin and heat removal rate in the layers. In conclusion, the limitation of the use of high current density Nb3Sn strands in high current conductors is discussed.

In view of the development of cables for next-generation fusion reactors, research activities are carried out on all HTS materials available from industrial production. Preliminary design of a react and wind cable using Bi-2212 wires is carried out, inspired by the Nb 3 Sn cable for European DEMO. The design and construction of a 60-kA prototype cable made of coated conductors have been carried out. The strands in the cable are composed of a stack of coated conductor tapes (4 mm wide) embedded in a copper profile of 6.3 mm in diameter. Tapes and copper profiles are soldered together in order to obtain a mechanically solid strand and to keep the inter tape resistance at a minimum, so that current can be easily redistributed among the tapes in a strand. The strands are fabricated in pieces 2 m long, but scaling up to industrial production should not present any major problem. A flat cable is manufactured by winding 20 strands around a central copper former; the cable will be inserted in a steel jacket for force flow cooling. The critical current of each strand was measured at liquid nitrogen in self-field just after the manufacturing process (twisted and straight) and after cabling: No reduction of the critical current was observed. Two pieces of cable, each 2 m long, are going to be prepared and assembled to form a sample that can be tested in the EDIPO facility.

The best performing HTS conductors are available in the form of thin tapes with operating current in the range of 200 A at the operating conditions. To realize conductors with high current carrying capability, in the range of several tens of kA, a large number of tapes must be assembled in a cable. The conventional stranding methods for round conductors are not applicable to thin tapes. CRPP has developed an assembly concept based on twisted stacks of tapes soldered into a copper profile. The ability to withstand bending and torsion strain is the main issue for the design of a high current flat cable based on twisted stacks of HTS tapes. An analytical mechanical model was developed and validated with the results of measurements. Parametric analyses are used to select the optimum layout for the first full size prototype of the coming HTS conductor for fusion. Various configurations of the cable are presented and compared, paying attention in particular to the strain acting in the tape. The chosen set of cable parameters satisfies electromechanical limitations and provides feasibility of strand winding.

In the Southern Hemisphere, evidence for preindustrial atmospheric pollution is restricted to a few geological archives of low temporal resolution that record trace element deposition originating from past mining and metallurgical operations in South America. Therefore, the timing and the spatial impact of these activities on the past atmosphere remain poorly constrained. Here we present an annually resolved ice core record (A.D. 793-1989) from the high-altitude drilling site of Quelccaya (Peru) that archives preindustrial and industrial variations in trace elements. During the precolonial period (i.e., pre-A.D. 1532), the deposition of trace elements was mainly dominated by the fallout of aeolian dust and of ash from occasional volcanic eruptions, indicating that metallurgic production during the Inca Empire (A.D. 1438-1532) had a negligible impact on the South American atmosphere. In contrast, a widespread anthropogenic signal is evident after around A.D. 1540, which corresponds with the beginning of colonial mining and metallurgy in Peru and Bolivia, ∼240 y before the Industrial Revolution. This shift was due to a major technological transition for silver extraction in South America (A.D. 1572), from lead-based smelting to mercury amalgamation, which precipitated a massive increase in mining activities. However, deposition of toxic trace metals during the Colonial era was still several factors lower than 20th century pollution that was unprecedented over the entirety of human history.

CRPP hosts two unique conductor test facilities SULTAN (SUpraLeiter TestANlage) and EDIPO (European DIPOle). They allow the test of high current superconductors in high magnetic fields (SULTAN 11 T, EDIPO 12.5 T). In both facilities sample currents up to 100 kA can be supplied by means of a NbTi transformer. Presently the facilities are upgraded for the test of high current high-temperature superconductor (HTS) samples. For HTS conductor testing at temperatures between 20 and 50K, the heat flux between the HTS sample under test and the NbTi transformer needs to be limited to around 10W per conductor leg by means of an HTS adapter connecting them. The second required upgrade is the supply of intermediate temperature helium (20-50 K) to the HTS test conductor. It is mandatory that the helium gas coming from the HTS conductor under test can be returned to the cryoplant as cold gas (T < 20K). To reach this goal a tube-in-tube heat exchanger has been manufactured in which 4.5K helium coming from the cryoplant is in counter flow with the warm gas leaving the HTS test conductor.