Study of the Mg-Nd alloy obtained by electrolysis in molten oxifluoride media

Mg-Nd alloys have been produced by electrolysis of the molten mixture LiF-NdF3-MgF2 using Nd2(CO3)3 and MgF2 as raw materials. An electrolysis cell was designed having the anode made of super dense graphite and the cathode made of molybdenum metal. The quasi-binary system (NdF3-LiF)eutectic-MgF2 was investigated and the liquidus line was determined using thermo-differential analysis. The solubility of Nd2(CO3)3 in the LiF-NdF3-MgF2 system was investigated by the carbothermal technique

Dislocation core field. I. Modeling in anisotropic linear elasticity theory

Aside from the Volterra field, dislocations create a core field, which can be modeled in linear anisotropic elasticity theory with force and dislocation dipoles. We derive an expression of the elastic energy of a dislocation taking full account of its core field and show that no cross term exists between the Volterra and the core fields. We also obtain the contribution of the core field to the dislocation interaction energy with an external stress, thus showing that dislocation can interact with a pressure. The additional force that derives from this core field contribution is proportional to the gradient of the applied stress. Such a supplementary force on dislocations may be important in high stress gradient regions, such as close to a crack tip or in a dislocation pile-up

Concentric double hollow grid cathode discharges

A new cathode system, consisting of two concentric spherical hollow grids with two aligned orifices, is investigated by space-resolved Langmuir probe measurements and non-linear dynamics analysis. Negative biases of this spherical hollow grids arrangement lead to the formation of two complex space charge structures in the regions of the orifices. The overall dynamics of the current-voltage characteristic (I–V characteristic) of each discharge is characterized by strong oscillatory behaviour with various waveforms correlated with jumps in the static I–V characteristics. Space-resolved measurements through the two aligned orifices of the two grids show a peak increase of the electron temperature and particle density in the regions of the two space-charge structures. The effects of the biases and Ar pressure on the overall spatial distribution of all plasma parameters are investigated. Two important working points of the concentric double hollow grid cathode discharges are revealed which could make this configuration suitable as an electron source

On the strength of the finite intersection principle

We study the logical content of several maximality principles related to the finite intersection principle (F\IP) in set theory. Classically, these are all equivalent to the axiom of choice, but in the context of reverse mathematics their strengths vary: some are equivalent to \ACA over \RCA, while others are strictly weaker, and incomparable with \WKL. We show that there is a computable instance of F\IP all of whose solutions have hyperimmune degree, and that every computable instance has a solution in every nonzero c.e.\ degree. In terms of other weak principles previously studied in the literature, the former result translates to F\IP implying the omitting partial types principle ($\mathsf{OPT}$). We also show that, modulo $\Sigma^0_2$ induction, F\IP lies strictly below the atomic model theorem ($\mathsf{AMT}$).Comment: This paper corresponds to section 3 of arXiv:1009.3242, "Reverse mathematics and equivalents of the axiom of choice", which has been abbreviated and divided into two pieces for publicatio

Evaluation of natural and tracer fluorescent emission methods for droplet size measurements in a diesel spray

The final publication is available at Springer via http://dx.doi.org/10.1007/s12239-012-0070-zSpray sizing that records fluorescent emission and scattered light has been widely applied to spray diagnostics over the last two decades. Different experimental strategies have been developed, but comparing the different solutions offered has remained of interest to experimentalists. In this work, a comparison of two fluorescence strategies for measuring droplet size in the liquid phase of a last-generation DI diesel spray is conducted. The natural fluorescent emission of a commercial diesel fuel and the fluorescence emitted by a tracer (Rhodamine B) are compared using theoretical and experimental approaches. The LIF/Mie ratio commonly called Planar Droplet Sizing (PDS) technique is applied in two different ways to elucidate the possible advantages of using a fluorescent dopant. The sprays were injected under non-evaporative conditions into a constant pressure vessel that simulates densities present at the moment of injection in currently used passenger car diesel engines. Characterization of the signal properties was performed by measuring the absorption coefficient, fluorescence emission spectrum, quantum yield and lifetime of both configurations. The scattered light and fluorescence intensities were calculated to verify the dependencies of the droplet surface and volume. When applying the two techniques to quantify droplet size in dense diesel sprays, the results show that signal weakness and lack of control over the properties of natural fluorescence produce distortion in the shape of the spray and cause measurements to be unreliable. © 2012 The Korean Society of Automotive Engineers and Springer-Verlag Berlin Heidelberg.This research has been funded in the frame of the project PROFUEL reference TRA2011-26293 from Ministerio de Ciencia e Innovacion. The injectors are part of the ECN international project.Pastor Soriano, JV.; Payri, R.; Salavert Fernandez, J.; Manin, J. (2012). Evaluation of natural and tracer fluorescent emission methods for droplet size measurements in a diesel spray. International Journal of Automotive Technology. 13(5):713-724. https://doi.org/10.1007/s12239-012-0070-zS713724135Albrecht, H. E., Damaschke, N., Borys, M. and Tropea, C. (2003). Laser Doppler and Phase Doppler Measurement Techniques. Springer. Berlin.Barnes, M. D., Whitten, W. B. and Ramsey, J. M. (1994). Enhanced fluorescence yields through cavity quantumelectrodynamic effects in microdroplets. J. Optical Society of America B 11,7, 1297–1304.Benajes, J., Molina, S., Novella, R., Amorim, R., Ben Hadj Hamouda, H. and Hardy, J. (2010). Comparison of two injection systems in an HSDI diesel engine using split injection and different injector nozzles. Int. J. Automotive Technology 11,2, 139–146.Charalampous, G. and Hardalupas, Y. (2011). Method to reduce errors of droplet sizing based on the ratio of fluorescent and scattered light intensities (laser-induced fluorescence/Mie technique). Applied Optics, 50, 3622–3637.Chen, G., Mazumder, M., Chang, R. K., Swindal, J. C. and Acker, W. P. (1996). Laser diagnostics for droplet characterization: Application of morphology dependent resonances. Progress in Energy and Combustion Science 22,2, 163–188.Desantes, J. M., Payri, R., Garcia, J. M. and Salvador, F. J. (2007). A contribution to the understanding of isothermal diesel spray dynamics. Fuel 86,7–8, 1093–1101.Domann, R. and Hardalupas, Y. A. (2000). Study of parameters that influence the accuracy of the planar droplet sizing (PDS) technique. Part. Part. Syst. Charact. 3–11.Domann, R. and Hardalupas, Y. A. (2001). Spatial distribution of fluorescence within large doplets and its dependence on dye concentration. Applied Optics 40,21, 3586–3597.Domann, R. and Hardalupas, Y. A. (2002). Quantitative measurement of planar droplet sauter mean diameter in sprays using planar droplet sizing. 11th Int. Symp. Application of Laser Techniques to Fluid Mechanics, Lisbon, Portugal.Eckbreth, A. C. (1988). Laser Diagnostics for Combustion Species and Temperature. Abacus. Cambridge. Mass.Greenhalgh, D. A. (1999). Planar measurements of fuel vapour, liquid fuel, liquid droplet size and soot. Planar Optical Measurement Methods for Gas Turbine Components, 1–7.Im, K., Lin, K., Lai, M. and Chon, M. (2011). Breakup modeling of a liquid jet in cross flow. Int. J. Automotive Technology 12,4, 489–496.Jermy, M. C. and Greenhalgh, D. A. (2000). Planar dropsizing by elastic and fluorescence scattering in sprays too dense for phase doppler measurement. Appl. Phys. B, 71, 703–710.Kim, Y., Kim, K. and Lee, K. (2011). Effect of a 2-stage injection strategy on the combustion and flame characteristics in a PCCI engine. Int. J. Automotive Technology 12,5, 639–644.Ko, F. H., Weng, L. Y., Ko, C. J. and Chu, T. C. (2006). Characterization of imprinting polymeric temperature variation with fluorescent Rhodamine B molecule. Microelectronic Engineering, 83, 864–868.Lakowicz, J. R. (2006). Principles of Fluorescence Spectroscopy. 3rd Edn. Springer.Lee, S. H., Teong, J., Lee, J. T., Ryou, H. S. and Hong, K. (2005). Investigation on spray characteristics under ultrahigh injection pressure conditions. Int. J. Automotive Technology 6,2, 125–131.Lee, B., Song, J., Chang, Y. and Jeon, C. (2010). Effect of the number of fuel injector holes on characteristics of combustion and emissions in a diesel engine. Int. J. Automotive Technology 11,6, 783–791.LeGal, P., Farrugia, N. and Greenhalgh, D. A. (1999). Laser sheet dropsizing of dense sprays. Optics and Laser Techn., 31, 75–83.Lockett, R. D., Richter, J. and Greenhalgh, D. A. (1998). The characterisation of a diesel spray using combined laser induced fluorescence and laser sheet dropsizing. Conf. Lasers and Electro-Optics Europe.Magde, D., Rojas, G. E. and Seybold, P. (1999). Solvent dependence of the fluorescence lifetimes of xanthene dyes. Photochem. Photobiol., 70, 737.Naber, J. and Siebers, D. (1996). Effects of gas density and vaporization on penetration and dispersion of diesel sprays. SAE Paper No. 960034.Pastor, J. V., López, J. J., Juliá, J. E. and Benajes, J. V. (2002). Planar laser-induced fluorescence fuel concentration measurements in isothermal diesel sprays. Opt. Express 10,7, 309–323.Pastor, J. V., Payri, R., Araneo, L. and Manin, J. (2009). Correction method for droplet sizing by laser-induced fluorescence in a controlled test situation. Optical Engineering 48,1, 013601.Payri, R., Garcia, J. M., Salvador, F. J. and Gimeno, J. (2005a). Using spray momentum flux measurements to understand the influence of diesel nozzle geometry on spray characteristics. Fuel, 84, 551–561.Payri, R., Salvador, F. J., Gimeno, J. and Soare, V. (2005b). Determination of diesel sprays characteristics in real engine in-cylinder air density and pressure conditions. J. Mech. Sci. Technol., 19, 2040–2052.Payri, R., Tormos, B., Salvador, F. J. and Araneo, L. (2008). Spray droplet velocity characterization for convergent nozzles with three different diameters. Fuel 87,15, 3176–3182.Payri, F., Pastor, J., Payri, R. and Manin, J. (2011). Determination of the optical depth of a DI diesel spray. J. Mech. Sci. Technol., 25, 209–219.Potz, D., Chirst, W. and Dittus, B. (2000). Diesel nozzle: The determining interface between injection system and combustion chamber. Conf. Thermo and Fluid-dynamic Processes in Diesel Engines, Valencia, Spain.Ramírez, A. I., Som, S., Aggarwal, S. K., Kastengren, A. L., El-Hannouny, E. M., Longman, D. E. and Powell, C. F. (2009). Quantitative X-ray measurements of highpressure fuel sprays from a production heavy duty diesel injector. Experiments in Fluids 47,1, 119–134.Schulz, C. and Sick, V. (2005). Tracer-LIF diagnostics: quantitative measurement of fuel concentration, temperature and fuel/air ratio in practical combustion systems. Progress in Energy and Combustion Science, 31, 75–121.Sjoback, R. and Nygren, J. and Kubista, M. (1998). Characterization of fluorescein—oligonucleotide conjugates and measurement of local electrostatic potential. Biopolymers, 46, 445–453.Soare, V. (2007). Phase Doppler Measurement in Diesel Dense Sprays: Optimisation of Measurements and Study of the Orifice Geometry Influence Over the Spray at Microscopic Level. Ph.D. Dissertion. E.T.S. Ingenieros Industriales. Universidad Politécnica de Valencia. Spain.Williams, A. T. R., Winfield, S. A. and Miller, J. N. (1983). Relative fluorescence quantum yields using a computer controlled luminescence spectrometer. Analyst., 108, 1067.Yeh, C. N., Kosaka, H. and Kamimoto, T. A. (1993). Fluorescence/scattering imaging technique for instantaneous 2-D measurements of particle size distribution in a transient spray. Proc. 3rd Cong. Opt. Part. Sizing, Yokohama, Japan, 335–361

Plasma physics and control studies planned in JT-60SA for ITER and DEMO operations and risk mitigation

| openaire: EC/H2020/633053/EU//EUROfusionA large superconducting machine, JT-60SA has been constructed to provide major contributions to the ITER program and DEMO design. For the success of the ITER project and fusion reactor, understanding and development of plasma controllability in ITER and DEMO relevant higher beta regimes are essential. JT-60SA has focused the program on the plasma controllability for scenario development and risk mitigation in ITER as well as on investigating DEMO relevant regimes. This paper summarizes the high research priorities and strategy for the JT-60SA project. Recent works on simulation studies to prepare the plasma physics and control experiments are presented, such as plasma breakdown and equilibrium controls, hybrid and steady-state scenario development, and risk mitigation techniques. Contributions of JT-60SA to ITER and DEMO have been clarified through those studies.Peer reviewe