The integrated engineering design concept of the upper limiter within the EU-DEMO LIMITER system

The EU-DEMO first wall protection relies on a system of limiters. Although they are primarily designed for facing the energy released by a limited plasma during transients, their design should safely withstand a combination of loads relevant for in-vessel components (IVCs) during steady-state operation. They are not meant to breed tritium, nor to provide plasma stability. However, sitting in place of blanket portions, they should ensure an adequate shielding function to vacuum vessel and magnets while withstanding both their dead weight and the electro-mechanical loads arising from the interaction between current induced in the conductive structure and magnetic field. During plasma disruptions they will be subjected to halo currents flowing from/to the plasma and the grounded structures, whose effects must be added to the eddy current ones. Disruption-induced electro-mechanical loads are hence IVC design-driving, despite the uncertainties in both eddy and halo currents’ magnitude and distribution, which depend on IVC design, electrical connectivity, plasma temperature and halo width. The integrated design of the limiter is made of two actively water-cooled sub-components: the Plasma-Facing Wall (PFW) directly exposed to the plasma, and the Shielding Block (SB) devoted to hold the PFW while providing neutronic shielding. The PFW design is driven by disruptive heat loads. Disruption-induced electro-magnetic loads are instead SB design drivers, meaning that the design details (i.e. geometry, electrical connections, attachments) affect the loads acting on it, which, in turn, are affected by the mechanical response of the structure. The present paper describes the design workflow and assessment of the Upper Limiter (UL), resulting from a close and iterative synergy among different fields. Built on static-structural and energy balance hand calculations based on, respectively, preliminary electro-magnetic and neutronic loads, the UL integrated design performance has then been verified against electro-magnetic, neutronic, thermal-hydraulic and structural assessment under the above-mentioned load combination. The outcome will be taken as reference for future limiter engineering designs

Distribution of ophthalmologists and optometrists in Islamic Republic of Iran and their associated factors Distribution des ophtalmologues et des optométristes en République islamique d�Iran et facteurs associés

We aimed to determine the distribution of ophthalmic care providers and its correlation with health and socioeconomic status and health system indicators. Data were gathered from the Iran Medical Council and the Iranian Societies of Ophthalmology and Optometry. Concurrent indicators were collected from the Statistical Center of Iran and national studies. A population-adjusted number of combined ophthalmologists and optometrists was used as the main dependent variable. Optometrist/ophthalmologist ratio was 0.9. We had 1 ophthalmologist and 1 optometrist for every 40 000 and 45 000 individuals, respectively. We observed a direct correlation between the number of ophthalmologists, optometrists and life expectancy at the provincial level. Gross provincial income and expenditure and provincial literacy were correlated as well. Provincial unemployment had a negative correlation. Provincial hospital statistics and population density were also significantly correlated. The Islamic Republic of Iran has met the World Health Organization�s desired per capita number of ophthalmologists and optometrists, but there is wide variation in their density. © 2016, World Health Organization. All rights reserved

Preliminary studies on SMA embedded wind turbine blades for passive control of vibration

Wind turbine blades are being bigger and bigger, thus requiring lightweight structures that are more flexible and thus more sensitive to dynamic excitations and to vibration problems. This paper investigates a preliminary architecture of large wind turbine blades, embedding thin sheets of SMA to passively improve their total damping. A phenomenological material model is used for simulation of strain-dependent damping in SMA materials and an user defined material model was developed for this purpose. The response of different architectures of SMA embedded blades have been investigated in the time domain to find an optimal solution in which the less amount of SMA is used while the damping of the system is maximize

Investigation of shape memory alloy embedded wind turbine blades for the passive control of vibrations

This paper investigates hybridized architectures of large wind turbine blade material with the aim to passively suppress uncontrolled vibration. The laminate composite layup of the blade was hybridized by embedding shape memory alloy (SMA) layers, in areas which are recognized as having a major role in the dissipation of energy. The embedded SMA thin sheet was laser patterned in order to improve the interface adhesion and to tailor the flexural stiffness requirement. The response of the blade with new architecture has been investigated in the time domain, to find an optimal composite layup in which the smallest amount of SMA is used while system damping is being maximized

Simulation of strain dependent damping in SMA embedded hybrid beams

This work describes modeling of non-linear damping behavior in hybrid beam structures with SMA embedded layers. The dependency of the intrinsic damping capacity of SMAs on the strain is simulated through modeling of material's hysteresis cycle. The hysteresis cycles and the corresponding loss-factors have been investigated through uniaxial tensile test and have been reproduced and validated by numerical simulation. To do so, a phenomenological hysteresis model has been developed and implemented in ABAQUS through UMAT interface. Finally, the method was used to simulate the damping of hybrid beam structures with SMA embedded layers and the results were compared with experimental data

A r c h i v e o f S I D Mortality from Pandemic Influenza A (H1N1) in Iran

Abstract Background: Due to worldwide spread of influenza A (H1N1) virus, the World Health Organization declared the first pandemic of influenza in four decades. This study aims to report the mortality from pandemic influenza A (H1N1) in Iran population and its epidemiologic and clinical characteristics up to December 21, 2009