EM zooming procedure in ANSYS Maxwell 3D

The severity of electromagnetic (EM) loads produced by plasma disruptions is one of the most concerning issues for the ITER in-vessel components design. To investigate the effects of fast EM transients on plasma surrounding structures during a disruption the Secondary Excitations (SE) method is used. This is an interface procedure to couple 2D plasma equilibrium codes with Finite Elements (FE) software. The Zooming Approach (ZA) used for the analyses presented here is a particular implementation of the SE method. The aim of this work is the demonstration that the ZA can be effectively applied in case of ANSYS Maxwell 3D analyses combining the ease of use of the Maxwell code with the computational efficiency of the ZA. The work has been carried out evaluating the EM loads acting on the ITER Diagnostic Equatorial Port Plug (EPP) during major disruptions scenario and comparing these loads with those obtained in previous analyses. Additional analyses have been performed to study the effect of ferromagnetic materials on EM loads in order to investigate ANSYS Maxwell capabilities in simulating non-linear magnetic properties

Direct spectrum of the benchmark t dwarf HD 19467 B

This is the final version of the article. Available from the American Astronomical Society / IOP Publishing via the DOI in this record.HD 19467 B is presently the only directly imaged T dwarf companion known to induce a measurable Doppler acceleration around a solar-type star. We present spectroscopy measurements of this important benchmark object taken with the Project 1640 integral field unit at Palomar Observatory. Our high-contrast R ≈ 30 observations obtained simultaneously across the JH bands confirm the cold nature of the companion as reported from the discovery article and determine its spectral type for the first time. Fitting the measured spectral energy distribution to SpeX/IRTF T dwarf standards and synthetic spectra from BT-Settl atmospheric models, we find that HD 19467 B is a T5.5 ± 1 dwarf with effective temperature Teff = 978+20 -43 K. Our observations reveal significant methane absorption affirming its substellar nature. HD 19467 B shows promise to become the first T dwarf that simultaneously reveals its mass, age, and metallicity independent from the spectrum of light that it emits.The TrenDS high-contrast imaging program is supported by NASA Origins of Solar Systems grant NNX13AB03G and the NASA Early Career Fellowship program. A portion of this work was supported by the National Science Foundation under Grant Numbers AST-0215793, 0334916, 0520822, 0804417 and 1245018. This work was partially supported by NASA ADAP grant 11-ADAP11-0169 and NSF award AST 1211568. A portion of the research in this Letter was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. J.A. is supported by the National Physical Science Consortium. This research has benefitted from the SpeX Prism Spectral Libraries, maintained by Adam Burgasser.1

Project 1640 Observations of Brown Dwarf GJ 758 B: Near-infrared Spectrum and Atmospheric Modeling

The nearby Sun-like star GJ 758 hosts a cold substellar companion, GJ 758 B, at a projected separation of $\lesssim$30 AU, previously detected in high-contrast multi-band photometric observations. In order to better constrain the companion's physical characteristics, we acquired the first low-resolution ($R \sim 50$) near-infrared spectrum of it using the high-contrast hyperspectral imaging instrument Project 1640 on Palomar Observatory's 5-m Hale telescope. We obtained simultaneous images in 32 wavelength channels covering the $Y$, $J$, and $H$ bands ($\sim$952-1770 nm), and used data processing techniques based on principal component analysis to efficiently subtract chromatic background speckle-noise. GJ 758 B was detected in four epochs during 2013 and 2014. Basic astrometric measurements confirm its apparent northwest trajectory relative to the primary star, with no clear signs of orbital curvature. Spectra of SpeX/IRTF observed T dwarfs were compared to the combined spectrum of GJ 758 B, with ${\chi}^2$ minimization suggesting a best fit for spectral type T7.0$\pm$1.0, but with a shallow minimum over T5-T8. Fitting of synthetic spectra from the BT-Settl13 model atmospheres gives an effective temperature $T_{\text{eff}}=741 \pm 25$ K and surface gravity $\log g = 4.3 \pm 0.5$ dex (cgs). Our derived best-fit spectral type and effective temperature from modeling of the low-resolution spectrum suggest a slightly earlier and hotter companion than previous findings from photometric data, but do not rule out current results, and confirm GJ 758 B as one of the coolest sub-stellar companions to a Sun-like star to date

Ignition conditions for inertial confinement fusion targets with a nuclear spin-polarized DT fuel

The nuclear fusion cross-section is modified when the spins of the interacting nuclei are polarized. In the case of deuterium?tritium it has been theoretically predicted that the nuclear fusion cross-section could be increased by a factor d = 1.5 if all the nuclei were polarized. In inertial confinement fusion this would result in a modification of the required ignition conditions. Using numerical simulations it is found that the required hot-spot temperature and areal density can both be reduced by about 15% for a fully polarized nuclear fuel. Moreover, numerical simulations of a directly driven capsule show that the required laser power and energy to achieve a high gain scale as d-0.6 and d-0.4 respectively, while the maximum achievable energy gain scales as d0.9

Nonlinear Finite Element Analysis Applied to the Development of Alpine Ski Safety Net

New technologies applied to the manufacturing of sport equipment allow skiers to reach velocities higher than in the past and, as a consequence, the number of serious accidents is increasing. Safety nets installed in the critical areas of the ski tracks can help to prevent the most severe consequences of an accident. In this paper, experimental tests and numerical simulations are introduced which were performed to characterise the behaviour of a safety net under static and dynamic loads and to support the development of a numerical tool to design high-performance safety net systems. As an application of the tool, the impact of a skier onto a high containment net was simulated and the risk level associated with the impact evaluated by means of injury criteria typical of crash analyses

Thermal tests of a scaled down mock-up of CP5.2 packaging system: Post-test analysis

In this study, the thermal performances of an Italian CP5.2 packaging system aimed at the transportation of bituminised wastes (i.e. engulfing fire of 800 °C for 30 min according to the IAEA regulation) are presented. Due to the high risk of auto-ignition of the bituminised wastes, that are stowed in the drums, in turn, immersed in the cement matrix of the CP 5.2, it was decided to test firstly a small scale mock-up. The mock up, containing only one drum with bituminised waste, was designed and built at the Department of Civil and Industrial Engineering (DICI) of the University of Pisa. The experimental test was carried out at Lab. Guerrini of the University of Pisa. Results demonstrated that after half an hour of fire exposure at 800 °C, the temperature in the bituminised waste package is below that of auto-ignition of the bitumen. The obtained results allowed in addition to set up the test procedure to adopt for fire test of a full scale CP5.2 system. Post test analysis, which was carried out by performing FEM analysis, is also presented and results compared to the experimental ones