This paper presents a remote and preparation-free method of temperature imaging of aqueous solutions in microchannels of microfluidic chips. The principle of this method is based on the temperature dependency of the near-infrared (NIR) absorption band (ν(2) + ν(3) band) of water. Temperature images were constructed from absorbances in a narrow wavelength range including 1908 nm, the most sensitive to temperature in the band, measured by using an NIR camera and an optical narrow-bandpass filter. Calculation and calibration results demonstrated a linear relationship between the absorption coefficient and temperature with a temperature coefficient of 1.5 × 10(-2) K(-1) mm(-1). Temperature images of 50 μm thick water in a Y-shaped PDMS microchannel locally heated by a neighboring hot wire were obtained, in which thermal diffusion processes in the microchip were visualized. Temperature resolution was estimated to be approximately 0.2 K according to the temperature coefficient and noise level.

For the establishment of a process for the electrochemical recovery of rare earth elements from used magnet scraps, the electrochemical formation of Pr-Ni alloys in molten LiF-CaF 2 -PrF 3 and NaCl-KCl-PrCl 3 salts at 1123 K and 973 K, respectively, was investigated.Cyclic voltammetry and open-circuit potentiometry indicated the formation of several phases of Pr-Ni alloys. Alloy samples were prepared by one-or two-step potentiostatic electrolysis using a Ni plate electrode at various potentials. Scanning electron microscopy observations and X-ray diffraction measurements confirmed the formation of PrNi 2 , PrNi 3 , Pr 2 Ni 7 , and PrNi 5 . The formation potential for each Pr-Ni alloy phase was determined from experimental results. In addition, the optimum electrolysis conditions for the separation of Nd, Dy, and Pr are discussed.Rare earth (RE) metals have several superior characters such as electric, magnetic, and fluorescence properties and are therefore indispensable as industrial materials throughout the world. Among the many applications of RE metals, the use of neodymium-ironboron (Nd-Fe-B) magnets-the so-called neodymium permanent magnets-has been remarkably increasing recently. Neodymium permanent magnets composed of a Nd 2 Fe 14 B main phase have several advantages such as superior magnetic properties and high mechanical strength, and are used for voice coil motors in hard disk drives (HDDs), magnetic resonance imaging (MRI), speakers/vibrators in cell phones, and motors in electric vehicles (EVs) and hybrid electric vehicles (HEVs). Since praseodymium (Pr) and Nd have similar chemical properties, they are found in nature in the same ores and their separation is difficult. Thus, in some applications including permanent magnets, a Nd-Pr alloy called didymium (Di) is sometimes utilized. On the other hand, Nd-Fe-B magnets have the drawback of a relatively low Curie temperature of ∼583 K. In order to maintain its superior coercive force even at high temperatures (above 473 K), where high-performance motors in EVs and HEVs operate, dysprosium (Dy) is necessary as an additive.One of the concerns pertaining to RE magnets is the uneven distribution of RE resources: in 2011, China had 50% of the proven RE reserves and produced over 97% of the global RE supply. 1 In 2010-2012, the price of REs increased sharply, causing supply problems for the magnets. While the present RE production capacity satisfies the demand and their price has lowered, there remains the potential for RE shortage in the future.On the basis of these supply circumstances, it can be concluded that the recycling or waste management of Nd-Fe-B magnet scraps is currently an urgent task. The conventional wet processes for RE recycling from Nd-Fe-B magnet scraps have several disadvantages such as their multistep and complicated processes, high environmental loads, and large energy consumption. As new recycling methods, pyrometallurgical processes such as chemical vapor transport, 2 selective reduction, 3 molten salt electrolysis, 4 and ionic liquid e...

The electrochemical formation of RE-Ni (RE=Pr, Nd and Dy) alloys was investigated in molten LiF-CaF2-REF3 systems at 1123 K. Cyclic voltammetry and open-circuit potentiometry indicated the formation of several phases of RE-Ni alloys. The formations of RENi2, RENi3 and RENi5 were confirmed by XRD and SEM/EDX. The formation potential for each alloy phase has been determined. The maximum Dy/Nd atomic ratio in the alloy estimated by EDX was 5.6. In molten LiCl-KCl-RECl3 (RE=Nd and Dy) systems at 723 K, the maximum Dy/Nd mass ratio in the alloy determined by ICP-AES was 121, indicating a high potentiality for the new separation/recovery process of Nd and Dy.

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The statistical properties of impurity transport of a tokamak edge plasma embedded in a dissipative drift-wave turbulence are investigated using structure function analysis. The impurities are considered as a passive scalar advected by the plasma flow. Two cases of impurity advection are studied and compared: A decaying impurities case (given by a diffusion-advection equation) and a driven case (forced by a mean scalar gradient). The use of extended self-similarity enables us to show that the relative scaling exponent of structure functions of impurity density and vorticity exhibit similar multifractal scaling in the decaying case and follows the She–Lévêque model. However, this property is invalidated for the impurity driven advection case. For both cases, potential fluctuations are self-similar and exhibit a monofractal scaling in agreement with Kolmogorov–Kraichnan theory for two-dimensional turbulence. These results obtained with a passive scalar model agree also with test-particle simulations.