Effect of Carbon Nanotube (CNT) Length on the Mechanical Milling of Ni-CNT Powders and Ni-CNT/Al Reactive Synthesis

Metallurgical and Materials Transactions A - The present paper investigates the effect of carbon nanotube (CNT) length (including the use of short multi-wall CNTs) and milling parameters on the...     

Reversible operation of La0·8Sr0·2MnO3 oxygen electrode infiltrated with Ruddlesden-Popper and perovskite lanthanum nickel cobaltite

The electrochemical performance and stability of La_0·8Sr_0·2MnO₃ oxygen electrodes infiltrated with La₂Ni_0·5Co_0·5O₄ (Ruddlesden-Popper) and LaNi_0·5Co_0·5O₃ (perovskite) nano-particles were studied under cyclic solid oxide electrolysis cell and solid oxide fuel cell modes. Electrochemical impedance spectroscopy and analysis of distribution of relaxation times were utilized to investigate the effect of addition of catalysts with Ruddlesden-Popper and perovskite structures on the reversible operation of electrochemical cells. Results indicated that addition of La₂Ni_0·5Co_0·5O₄ nanoparticles has more impact on polarization resistance reduction as compared to LaNi_0·5Co_0·5O₃ in cyclic operation, probably due to the facile oxygen transport in the rock salt layer of Ruddlesden-Popper structure. Analysis of the polarization resistance fluctuations shows a better stability in Ruddlesden-Popper structure-infiltrated electrodes as compared to perovskite structure. The difference between maximum and minimum of polarization resistances (i.e. fluctuations) in cyclic operation is reduced significantly by introducing Ruddlesden-Popper-structured lanthanum nickel cobaltite nanoparticles.     

Thermal properties of particulate TIMs in squeeze flow

Direct numerical simulations based on a thermal Lattice–Boltzmann method are utilized to compute the effective thermal conductivity of particulate thermal interface materials (TIMs). By simulating the squeezing process, we obtain the particle distribution in a situation similar to application. Therefore, there is no need to calculate the average thermal characteristics from several pre-defined random distributions. The effects of particle volume fraction, particle size, and particle to matrix thermal conductivity ratio on the thermal performance are investigated. The results for the effective thermal conductivity are in agreement with the existing semi-analytical and experimental results reported in the literature.     

1.3 μm GaInAsP near-travelling-wave laser amplifiers made bycombination of angled facets and antireflection coatings

1.3 μm GaInAsP near-travelling-wave laser amplifiers have been realised by the combination of angled facets and antireflection coatings. Without in situ monitoring on the device itself during dielectric coatings, one can routinely obtain a low effective modal facet reflectivity of 5-8×10^-4. The devices had an internal gain of 24±1.5 dB for the TE mode and a single-mode fibre coupling loss of 5 dB/facet     

A new technique for micro-patterning of nanoparticles on non-conductive substrate by low frequency AC electrophoresis

Electrophoretic deposition (EPD) has been known as a cost-effective and simple method in shaping or coating ceramic parts. Usefulness of this electrically driven method becomes more pronounced when it is applied for manipulating nanosize materials. Our findings in this area have showed that nanoparticle manipulation with EPD method is possible through applying low frequency alternating current (AC) electric fields. In our previous work, we explained how nanoparticles fill the non-conductive gap between two in-plane electrodes at frequency of 1 Hz. In this work, we used the similar idea to deposit TiO₂ nanoparticles on non-conductive Alumina base in direction parallel to the electrode edge. The length and width of TiO₂ deposited line was in the order of micrometer and coherency of deposited layer was good. It was concluded that with designing different electrode shapes, micro-patterning of ceramic nanoparticles on different substrates via low frequency AC electrophoretic deposition is possible.     

Ternary elastomer nanocomposites based on NR/BR/SBR: Effect of nanoclay composition

Elastomer nanocomposites based on natural rubber (NR), butadiene rubber (BR), and styrene butadiene rubber (SBR) containing Cloisite 15A were prepared using a two‐roll mill. Mechanical, morphological, and rheological characterization of the prepared nanocomposites was carried out in order to study the effect of different nanoclay compositions, i.e., 1, 3, 5, 7, and 10 wt %. Intercalation of the elastomer chains into the silicate layers was evidenced by d‐spacing values calculated according to the results of the X‐ray diffraction (XRD) patterns. This was directly confirmed by transmission and scanning electron microscopy (TEM and SEM). The results depict a decreasing trend in the optimum cure time (t₉₀) and scorch time (t₅) values of the nanocomposite samples with increasing nanoclay loading; where the elastic modulus (G′) and complex viscosity (η*) of the samples considerably increased. The mechanical properties of the nanocomposites show a considerable increase in the tensile modulus of NR/BR/SBR/Cloisite 15A nanocomposites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013