530 research outputs found

    Update On The Code Intercomparison and Benchmark For Muon Fluence and Absorbed Dose Induced By An 18-GeV Electron Beam After Massive Iron Shielding

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    In 1974, Nelson, Kase and Svensson published an experimental investigation on muon shielding around SLAC high-energy electron accelerators. They measured muon fluence and absorbed dose induced by 14 and 18 GeV electron beams hitting a copper/water beamdump and attenuated in a thick steel shielding. In their paper, they compared the results with the theoretical models available at that time. In order to compare their experimental results with present model calculations, we use the modern transport Monte Carlo codes MARS15, FLUKA2011 and GEANT4 to model the experimental setup and run simulations. The results are then compared between the codes, and with the SLAC data.Comment: 14 pp. Presented paper at the 13th Meeting of the task-force on Shielding aspects of Accelerators, Targets and Irradiation Facilities (SATIF-13), HZDR, October 10-12, 2016, Dresden, Germany. arXiv admin note: substantial text overlap with arXiv:1502.0168

    Successful Coronary Stent Retrieval From a Pedal Artery

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    The purpose of this article is to report complications from a coronary drug-eluting stent lost in the peripheral circulation. We report the case of successful retrieval of a sirolimus coronary stent from a pedal artery in a young patient who underwent coronary angiography for previous anterior myocardial infarction. Recognition of stent embolization requires adequate removal of the device to avoid unwelcome clinical sequelae. Keywords Coronary stent Microsnare technique Peripheral embolization Stent retrieva

    THE CASTLE OF ASSORO: THE INTEGRATED SURVEY FOR THE KNOWLEDGE AND CONSERVATION OF RUINS

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    Assoro is an ancient city located in the heart of Sicily. Its fame in the Middle Ages is linked to the strategic location of its primitive nucleus placed at the top of Monte Stella. The fortified site allowed, in fact, both the defence of the surrounding territory and the control of the internal crossings of the island, from east to west. Today, the ruins of the castle, still visible in the highest part of the city, are enclosed in a large urban park that neither enhances nor facilitates its understanding. Actually, the knowledge of the monument is very incomplete due to the lack of documentary sources. To compensate these gaps new investigations were undertaken. Survival masonries were examined by a careful visual investigation and a deep survey, both for the stratigraphic, material and degradation aspects, carried out through the integrated use of active and passive sensors instruments. The critical analyses arising from the appropriately constructed 3D models and the photo-realistic orthographic projections with the mapping of the different constructive phases, the building materials and decay, was laid as the foundation of the cognitive process aimed at the establishment of a sustainable conservation and valorisation project. The programme has also foreseen the realisation of some archaeological coverings and the improvement of the whole park fruition, through paths that aim to both ensure easier access to some rocky archaeological areas currently difficult to reach and greater integration and permeability, between the historic urban fabric and the park

    Correction to: New eco-friendly low-cost binders for Li-ion anodes

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    The article New eco-friendly low-cost binders for Li-ion anodes, written by D. Versaci, R. Nasi, U. Zubair, J. Amici, M. Sgroi, M. A. Dumitrescu, C. Francia, S. Bodoardo and N. Penazzi, was originally published electronically on the publisher's internet portal (currently SpringerLink)

    Designing a double-coated cathode with high entropy oxides by microwave-assisted hydrothermal synthesis for highly stable Li–S batteries

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    Nowadays, Li-S batteries are considered as one of the most promising alternatives to Li-ion technology in the near future, thanks to their high specific capacity and their significantly lower environmental impact and production costs. Consequently, many efforts have been directed to tackle with the inherent issues that affect Li-S batteries. One of the main problems is the so-called shuttle effect, which basically entails the unwanted migration of lithium polysulfides (LiPSs) from the cathode to the anode side, causing the degradation of the cell. Here, we report an effective strategy to restrain the shuttle effect and increase the kinetics at the cathode of the lithium-sulfur (Li-S) battery. A functional layer including high entropy oxides (HEO) coated onto the sulfur cathode allows to exploit the HEOs capability as promoter catalysts for the conversion of LiPSs. Pure HEO powders are synthesized by fast, highly efficient microwave irradiation, followed by heat treatment at 930 degrees C. The formation of highly crystalline HEO is confirmed by X-ray diffraction analysis. The LiPSs adsorption capability of HEO is evaluated by UV-vis and X-ray photoelectron spectroscopy analyses. The effect of the HEO-coated sulfur cathode on the electrochemical performance of the Li-S battery is studied by cyclic voltammetry and galvanostatic charge/discharge. The cell with double-coated cathode delivers an initial discharge capacity of 1173 mAh/g at C/10 with 45% capacity retention over 500 cycles at C/5, approaching similar to 99% coulombic efficiency.[GRAPHICS]

    Estudio de superficie de α - FE y aceros inoxidables implantados con ¹²C⁻

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    Se han implantado iones ¹²C⁻ con una energía de 180 keV y una dosis del orden de 10¹⁷ at / cm² en a - Fe y en aceros inoxidables AISI304 y 316 en distintas fases en equilibrio. Se estudian las modificaciones superficiales que tienen lugar atendiendo a sus anteriores estados cristalinos. Se observaron cambios importantes en las superficies de las muestras implantadas tales como la formación de ampollas (blisters), escamas (flakes), y ataque preferencial producidos por el impacto de los iones sobre la superficie. Se relacionan las modificaciones superficiales con las estructuras cristalinas de las muestras previas a la implantación.Facultad de Ciencias Exacta

    Carotid artery stenting: a single-centre experience with up to 8 years' follow-up

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    Carotid artery stenting (CAS) may be an alternative to surgical endoarterectomy not only in high-risk patients. We report results in the endovascular treatment of carotid artery disease with up to 8 years' follow-up. In this retrospective study, we analysed data from 853 consecutive patients (946 arteries) treated for carotid artery stenosis between April 1999 and March 2007; 491 (52%) arteries were symptomatic and 455(48%) were asymptomatic. Preprocedural evaluation of the patients was performed with echo Doppler, magnetic resonance angiography (MRA) or computed tomographic angiography (CTA) and a neurological examination. A cerebral protection device was used in 879 (92.9%) procedures. Anti-platelet therapy was administered before and after the procedure. All patients were included in a follow-up of up to 8 years. Technical success was achieved in 943 (99.6%) lesions. At 30 days, there was a 0.21% (n = 2) death rate, a 0.42% major stroke rate, a 1.69% minor stroke/transient ischaemic attack (TIA) rate and a combined 2.32% TIA/stroke and death rate. During follow-up, echo Doppler evidenced restenosis in 39 (4.85%) cases; of these, only five, presenting restenosis > 80%, were treated with an endovascular reintervention. At the long-term follow-up, two strokes (0.23%) were reported, which both occurred within the first 2 years. In our experience, carotid artery stenting seems to be a safe and effective treatment, providing satisfactory long-term clinical results

    Irradiation of luminescence dosimeters in pulsed mixed radiation fields

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    UHDpulse - Metrology for Advanced Radiotherapy using beams with Ultra-High Pulse Dose Rates is a European project aimed at developing novel dosimetry standards, as well as improving existing ones, for FLASH radiotherapy, very high energy electrons radiotherapy, and laser-driven medical accelerators. Within the scope of this project, Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) detectors are used to measure stray radiation fields. Experiments performed with conventional pulsed particle-beams allow to characterize the dosimeters in known and controllable radiation fields. In turn, this allows to develop models and predict their behavior in complex radiation fields, such as those at laser-driven and FLASH facilities. TL and OSL detectors were irradiated at the Microtron MT25 electron accelerator in Prague, Czech Republic. GAFChromicTM films and plastic nuclear track detectors were used to study the beam profile and the neutron background respectively. The responses of the different detector to the pulsed mixed radiation fields of the Microtron MT25 are compared among each other and presented in this paper

    Gamma-Flash Generation in Multi-Petawatt Laser-Matter Interactions

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    The progressive development of high power lasers over the last several decades, enables the study of γ\gamma-photon generation when an intense laser beam interacts with matter, mainly via inverse Compton scattering at the high intensity limit. γ\gamma-ray flashes are a phenomenon of broad interest, drawing attention of researchers working in topics ranging from cosmological scales to elementary particle scales. Over the last few years, a plethora of studies predict extremely high laser energy to γ\gamma-photon energy conversion using various target and/or laser field configurations. The aim of the present manuscript is to discuss several recently proposed γ\gamma-ray flash generation schemes, as a guide for upcoming γ\gamma-photon related experiments and for further evolution of the presently available theoretical schemes.Comment: 12 pages, 8 figure

    Comparative indoor pollution from Glo, Iqos, and Juul, using traditional combustion cigarettes as benchmark. Evidence from the randomized sur-vapes air trial

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    Modified risk products (MRP) such as electronic vaping cigarettes (EVC) and heat-not-burn cigarettes (HNBC) are appealing alternatives to combustion cigarettes. Limited between-and within-device comparative data are available on MRP. We aimed at comparing indoor particulate matter (PM) emissions measured in a randomized trial enforcing standardized smoking sessions, testing different devices and flavors of MRP, using traditional combustion cigarettes (TCC) as benchmark. Overall, MRP yielded significantly lower levels of indoor PM in comparison to TCC (with median PM levels during smoking for MRP < 100 µg/m3, and for TCC > 1000 µg/m3). Despite this, significant differences among MRP were found, with Iqos appearing associated with a significantly lower burden of emissions for all the monitored fractions of PM, including total PM (all p < 0.05). Precisely, during use, PM ≤ 1 µm (PM1) emissions were 28 (16; 28) µg/m3 for Glo, 25 (15; 57) µg/m3 for Iqos, and 73 (15; 559) µg/m3 for Juul (p < 0.001 for Glo vs. Iqos, p <0.001 for Glo vs. Juul, and p = 0.045 for Iqos vs. Juul). Exploratory within-MRP analyses suggested significant differences between flavors, favoring, for instance, Ultramarine for Glo, Bronze for Iqos, and Mango for Juul, even if results varied substantially according to individual smoker. In conclusion, leading MRP have significantly less intense and persistent effects on indoor pollution in comparison to TCC. Yet, when focusing solely on MRP, between-product and between-flavor differences appear, with quantitative estimates suggesting lower polluting effects with Iqos. These results, if confirmed externally, could be used to individualize product and flavor choice to minimize the untoward effects of EVC and HNBC on indoor pollution
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