Novel approach to recover copper ions using poly(ethylene imine) based layer-by-layer coatings on icosane particles

The low-density materials are developed for the wastewater treatment, the particles could be easily recovered when floating upon water surface and be recycling of a large fraction. Simultaneously, we selected the low melting point of material, which is possible to separate easily the compounds after usage. We chose icosane as a core material with layer-by-layer (LbL) films as an adsorbent for wastewater containing copper ions. The icosane particles were coated by poly(ethylene imine) (PEI) as positively charged layer and either poly(acrylic acid) (PAA) or poly(styrene sulfonate) as counterpart. Glutaraldehyde was introduced as a crosslinking agent to create multilayered shells with various active sites as scavenger. The copper adsorption abilities of PEI-PAA-coated particles were examined by inductively coupled plasma mass spectrometry. Interestingly, the adsorption amount of copper ions on PEI/PAA coated particles (16.5 mg) was optimized at 82 μg/L after 5 min of elution time, which shows a good potential of our material in the field of application. With the facile and consistent separation of the core and LbL coating, the thermal properties were revealed a stable melting temperature at around 38°C.     

Reinvestigation of Ni-solid solution/liquid equilibria in Ni-Al binary and Ni-Al-Zr ternary systems

The present work reports the results of a reinvestigation of the γ liquidus and solidus temperatures of the Ni-Al system and the γ/Ni₅Zr eutectic reaction temperatures in the Ni-Al-Zr system. In the Ni-Al binary system, it is found that the stability of the Ni-rich γ solid solution phase is enhanced by small additions of Al with the melting temperature of the γ phase and that the melting temperature reaches a congruent maximum at a few at.% Al. The temperature of the eutectic reaction L→γ+Ni₅Zr in the Ni-Zr binary edge is confirmed to be 1196 °C by differential thermal analysis (DTA), rather higher than the value reported previously. The reaction temperature increases with Al addition to reach or exceed 1206 °C, forming a “saddle point,” then decreasing to reach 1187 °C or below by flowing into a ternary invariant reaction. These findings can be explained by γ/liquid equilibrium in the Ni-Al binary system.     

Research on wet steam spontaneous condensing flows considering phase transition and slip

A new dual-fluid model considering phase transition and velocity slip was proposed in this paper and the Cunningham correction was used in the droplet resistance calculation. This dual-fluid model was applied to the numerical simulations of wet steam flow in a 2D LAVAL nozzle and in the White cascade respectively. The results of two simulations demonstrate that the model is reliable. Meanwhile, the spontaneous condensing flow in White cascade was analyzed and it infers that the irreversible loss caused by condensation accounts for the largest share (about 8.78% of inlet total pressure) in total pressure loss while the loss caused by velocity slip takes the smallest share (nearly 0.42%), and another part of total pressure loss caused by pneumatic factors contributes a less share than condensation, i.e. almost 3.95% of inlet total pressure.     

Linear and non-linear stability analyses of thin-walled beams with monosymmetric I sections

The paper investigates beam lateral buckling stability according to linear and non-linear models. First, the classical linear stability solutions are derived from the stability equation in the case of monosymmetric cross-sections. Bending distribution, load height parameter and Wagner's coefficient effects are taken into account. In the second step, they are extended to non-linear stability by considering pre-buckling deformation and improved solutions are then obtained. Based on a finite element model developed for large torsion of thin-walled beams with open sections, the stability of beams under gradient moments (M₀, ψM₀, ?1≤ψ≤1) is particularly investigated. It is then concluded that beam lateral buckling resistance depends not only on pre-buckling deformation but also on section shape and load distribution. For bisymmetric I beam, closed form solutions are possible and pre-buckling deformations have an incidence. In the case of beams with monosymmetric I and Tee sections, effects of pre-buckling deflections are important only when the largest flange is in compression under M₀ and positive gradient moment. Analytical solutions are possible. For negative gradient moments all available solutions fail and numerical solutions are more powerful. Effect of gradient moments on stability of redundant beams is investigated at the end. Under such boundary conditions, important axial forces are present due to non-linear beam deformation. These forces, omitted in literature, have an incidence on stability. The element is then concerned with beam-column behaviour rather than beam stability.     

Sintering of titanium metal

Stoichiometric TiH₂ powder, which is stable in air, was used as a starting material in the sintering of titanium metal. Powder compacts of stoichiometric TiH₂ , finely ground in air, were fired in vacuum to remove the hydrogen, and then sintered. Using this method the Ti particles did not experience surface oxidation, which would otherwise usually occur, and the powder showed good sinterability, giving a sintered density above 98% of theoretical at the relatively low temperature of 1000°C     

Phase diagram of Ni3V-Co3V pseudobinary system

A phase diagram of Ni₃V-Co₃V pseudobinary system is proposed based on x-ray diffraction and differential thermal analysis. Four invariant reactions are located in the phase diagram—two eutectoid and two peritectoid reactions. Six kinds of geometrically close-packed phases are encountered. The stability of these close-packed phases correlate well with the electron concentration.     

Theoretical Investigation of Phase Equilibria for Metal-Hydrogen Alloy

Cluster variation method (CVM) was applied to calculate phase equilibria of metal-hydrogen systems. Two subjects are introduced in the present report. One is the summary of previous studies on the Pd-H system, and it is demonstrated that a single CVM free energy formula can systematically derive information of phase equilibria, intrinsic stability, and short range order diffuse intensities. The second subject is the theoretical calculations of superabundant vacancy (SAV) formation. Within the square approximation of the CVM, it is shown that abundant vacancies are introduced with the absorption of hydrogen when the interaction between vacancy and hydrogen is considered. This article was presented at the Multi-Component Alloy Thermodynamics Symposium sponsored by the Alloy Phase Committee of the joint EMPMD/SMD of The Minerals, Metals, and Materials Society (TMS), held in San Antonio, Texas, March 12-16, 2006, to honor the 2006 William Hume-Rothery Award recipient, Professor W. Alan Oates of the University of Salford, UK. The symposium was organized by Y. Austin Chang of the University of Wisconsin, Madison, WI, Patrice Turchi of the Lawrence Livermore National Laboratory, Livermore, CA, and Rainer Schmid-Fetzer of the Technische Universitat Clausthal, Clauthal-Zellerfeld, Germany.     

Three-dimensional shaping by dot-matrix electrical discharge machining

This paper deals with a new prototyping method called dot-matrix electrical discharge machining (EDM) with scanning motion. The machining process by the dot-matrix method is similar to printing motion with a dot-impact printer. This method can be applied not only to EDM but also electrochemical machining and forming. A prototype of the machining unit for the dot-matrix method has six feeding devices for thin wire electrodes. The electrodes of 300 μm in diameter are arranged with the pitches of 760 μm. To obtain a smooth surface, a planetary motion in the x-y-plane is added to the feeding of the machining unit in the z-direction, the same area is machined repeatedly, or the machining unit is moved with fine feed. By compensating for the wear of the electrode during the scanning EDM, various shapes with the accuracy of micrometers order can be obtained without a formed tool electrode.