Proposal of a novel design for linear superconducting motor using 2G tape stacks

This paper presents a new design for a su- perconducting linear motor (SLM). This SLM uses stacks of second-generation (2G) superconducting tapes, which are responsible for replacing yttrium barium copper oxide bulks. The proposed SLM may operate as a synchronous motor or as a hysteresis motor, depending on the load force magnitude. A small-scale linear machine prototype with 2G stacks was constructed and tested to investigate the proposed SLM topology. The stator traveling magnetic field wave was represented by several Nd-Fe-B permanent magnets. A relative movement was produced between the stator and the stack, and the force was measured along the displacement. This system was also simulated by the finite element method, in order to calculate the induced currents in the stack and determine the electromagnetic force. The H-formulation was used to solve the problem, and a power law relation was applied to take into account the intrin- sically nonlinearity of the superconductor. The simulated and measured results were in accordance. Simulated re- sults were extrapolated, proving to be an interesting tool to scale up the motor in future projects. The proposed motor presented an estimated force density of almost 500 N/kg, which is much higher than any linear motor.This work was supported in part by the following agencies: CNPq/CAPES/INERGE, CNPq—Ci ˆ encias sem Fronteiras, FAPERJ, Catalan Government 2014- SGR-753, CONSOLIDER Excellence Network MAT2014-56063-C2-1-R and MAT2015-68994-REDC, Eurofusion EU COST ACTIONS MP1201/ MP1014/PPPT-WPMAG 2014, EUROTAPES FP7-NMP-Large-2011- 280432, FORTISSIMO FP7-2013-ICT-609029, and Spanish Govern- ment Agencies—Severo Ochoa Programme Centres of Excellence in R&D. (Corresponding author: Guilherme G. Sotelo.

From oil field to geothermal reservoir: assessment for geothermal utilization of two regionally extensive Devonian carbonate aquifers in Alberta, Canada

The Canadian province of Alberta has one of the highest per capita CO2-equivalent emissions in Canada, predominantly due to the industrial burning of coal for the generation of electricity and mining operations in the oil sands deposits. Alberta's geothermal potential could reduce CO2 emissions by substituting at least some fossil fuels with geothermal energy.The Upper Devonian carbonate aquifer systems within the Alberta Basin are promising target formations for geothermal energy. To assess their geothermal reservoir potential, detailed knowledge of the thermophysical and petrophysical rock properties is needed. An analogue study was conducted on two regionally extensive Devonian carbonate aquifers, the Southesk-Cairn Carbonate Complex and the Rimbey-Meadowbrook Reef Trend, to furnish a preliminary assessment of the potential for geothermal utilization. Samples taken from outcrops were used as analogues to equivalent formations in the reservoir and correlated with core samples of the reservoir. Analogue studies enable the determination and correlation of facies-related rock properties to identify sedimentary, diagenetic, and structural variations, allowing for more reliable reservoir property prediction.Rock samples were taken from several outcrops of Upper Devonian carbonates in the Rocky Mountain Front Ranges and from four drill cores from the stratigraphically equivalent Leduc Formation and three drill cores of the slightly younger Nisku Formation in the subsurface of the Alberta Basin. The samples were analyzed for several thermophysical and petrophysical properties, i.e., thermal conductivity, thermal diffusivity, and heat capacity, as well as density, porosity, and permeability. Furthermore, open-file petrophysical core data retrieved from the AccuMap database were used for correlation.The results from both carbonate complexes indicate good reservoir conditions regarding geothermal utilization with an average reservoir porosity of about 8&thinsp;%, average reservoir permeability between 10−12 and 10−15&thinsp;m2, and relatively high thermal conductivities ranging from 3 to 5&thinsp;W m−1 K−1. The most promising target reservoirs for hydrothermal utilisation are the completely dolomitized reef sections. The measured rock properties of the Leduc Formation in the subsurface show no significant differences between the Rimbey-Meadowbrook Reef Trend and the Southesk-Cairn Carbonate Complex. Differences between the dolomitized reef sections of the examined Leduc and Nisku Formation are also minor to insignificant, whereas the deeper basinal facies of the Nisku Formation differs significantly.In contrast, the outcrop analogue samples have lower porosity and permeability, likely caused by low-grade metamorphism and deformation during the Laramide orogeny that formed the Rocky Mountains. As such, the outcrop analogues are not valid proxies for the buried reservoirs in the Alberta Basin.Taken together, all available data suggest that dolomitization enhanced the geothermal properties, but depositional patterns and other diagenetic events, e.g., fracturing, also played an important role.</p

Blue is the fashion in Mediterranean pines: New drought signals from tree-ring density in southern Europe

Identificador de proyecto: Marie Sklodowska-Curie grant agreement No 101029581Long-term records of tree-ring width (TRW), latewood maximum density (MXD) and blue intensity (BI) measurements on conifers have been largely used to develop high-resolution temperature reconstructions in cool temperate forests. However, the potential of latewood blue intensity (LWBI), less commonly used earlywood blue intensity (EWBI), and delta (difference between EWBI and LWBI, dBI) blue intensity in Mediterranean tree species is still unexplored. Here we developed BI chronologies in moist-elevation limits of the most southwestern European distribution of Pinus nigra subsp. salzmanii Arnold. We tested whether BI variables derived from tree rings of black pine are better proxies than ring-width variables to reconstruct long-term changes in climatic factors and water availability. For this we applied correlations and regression analyses with daily and monthly climate data, a spatial and temporal drought index (Standardized Precipitation-Evapotranspiration Index-SPEI) and Vapour Pressure Deficit (VPD), as well as atmospheric circulation patterns: North Atlantic Oscillation (NAO), Southern Oscillation Index (SOI) and Western Mediterranean Oscillation (WeMO). We found a positive relation between black pine growth (RW) and temperature during the winter preceding the growing season. Among all variables LWBI and dBI were found to be more sensitive than TRW to SPEI at low-elevation site, with EWBI series containing an opposite climatic signal. LWBI and dBI were significantly related to June and September precipitation at high-elevation site. Winter VPD was related with higher EWI and LWI series, whereas dBI and EWBI were related with January SOI and February NAO. We confirm the potential of long-term dBI series to reconstruct climate in drought-prone regions. This novel study in combination with other wood anatomical measurements has wide implications for further use of BI to understand and reconstruct environmental changes in Mediterranean conifer forests.Wageningen University & ResearchUniversidade de Santiago de CompostelaUniversity of Amsterda

Tetraploidy in \u3ci\u3eMelilotus alba\u3c/i\u3e induced by colchicine

Seedlings of sweet clover were treated with colchicine. Plants that responded to treatment either were tetraploid in all new root tissues, or had sectors, or islands of tetraploid tissue in the root tips. Cutting made from the plants in the latter category were tetraploid throughout

Implementation of a 3D solver for electric arc welding, coupling fluid mechanics with electromagnetics

Paper presented at the 8th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Mauritius, 11-13 July, 2011.This paper describes the implementation of a 3D numerical solver for electric arc welding, where the fluid mechanics of the shielding gas is strongly influenced by the electromagnetic fields. The implementation is done in the OpenFOAM-1.6.x OpenSource Computational Fluid Dynamics (CFD) tool (www.openfoam.com). OpenFOAM is basically a general library of C++ classes for numerical simulation of continuum mechanic problems, but it is mainly used in CFD. The basics of high-level programming in OpenFOAM is described briefly, while the main components of the implementation done in the present work are described in high detail. The implementation is validated against an analytical solution of the electromagnetic field of an infinite electrically conducting rod, and against an experimental study of GTAW (Gas Tungsten Arc Welding). The numerical results agree very well with both the analytical and experimental results. A grid-dependency study has been made for the GTAW case, showing that the main features of the presented solutions are independent of the mesh size.mp201

Implementation of a 3D solver for electric arc welding, coupling fluid mechanics with electromagnetics

Paper presented at the 8th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Mauritius, 11-13 July, 2011.This paper describes the implementation of a 3D numerical solver for electric arc welding, where the fluid mechanics of the shielding gas is strongly influenced by the electromagnetic fields. The implementation is done in the OpenFOAM-1.6.x OpenSource Computational Fluid Dynamics (CFD) tool (www.openfoam.com). OpenFOAM is basically a general library of C++ classes for numerical simulation of continuum mechanic problems, but it is mainly used in CFD. The basics of high-level programming in OpenFOAM is described briefly, while the main components of the implementation done in the present work are described in high detail. The implementation is validated against an analytical solution of the electromagnetic field of an infinite electrically conducting rod, and against an experimental study of GTAW (Gas Tungsten Arc Welding). The numerical results agree very well with both the analytical and experimental results. A grid-dependency study has been made for the GTAW case, showing that the main features of the presented solutions are independent of the mesh size.mp201