Effect of oxygen flow rate on the structural and electrochemical properties of lithium nickel oxides synthesized by the sol–gel method

The structural and electrochemical properties of LiNiO₂ powders were investigated as a function of the oxygen flow rate employed in the preparation of lithium nickel oxide. It was found that oxygen played an important role in the synthesis of highly crystallized LiNiO₂(R3¯m). In the crystallization process of LiNiO₂, a deficiency of oxygen in the calcination reactor induced the formation of impurities and cubic rock-salt structure (Fm3m) in LiNiO₂ powders. For LiNiO₂ prepared at higher oxygen flow rates, the electrode delivered high discharge capacities with relatively good retention rates. But very low electrode capacity was obtained from LiNiO₂ prepared at lower oxygen flow rates.     

Ultrafiltration of lake water for potable water production

Ultrafiltration with coagulation or powdered activated carbon pretreatment is used to treat water from a public water supply. While UF without pretreatment is effective in removing turbidity, pretreatment prior to UF greatly enhances the removal of natural organic matter and trihalomethane precursors. Short-term flux loss can be minimized with backflushing, while long-term irreversible fouling seems to be affected most by the type of membrane polymer.     

Suppressing harmonic vibrations of a miniature cryogenic cooler using an adaptive tunable vibration absorber based on magneto-rheological elastomers

This paper presents dynamic performances of an adaptive tunable vibration absorber (TVA) designed to suppress the main harmonic disturbance of a miniature linear cryogenic cooler, which is being used in space applications such as an observation satellite. The adaptive TVA employs a magneto-rheological elastomer (MRE) for a variable stiffness element. This study first investigates the shear modulus change of MRE samples with respect to the magnetic flux density, which varies through the alignment of particle chains. The MRE with the maximal shear modulus change is mounted for the TVA on a prototype cooler, which emulates the characteristics of a miniature cryogenic cooler. Using the test setup, a series of vibration tests are performed to evaluate the performance and efficacy of the MRE TVA and its re-tuning ability. The experimental results show that the MRE TVA is able to robustly suppress the vibration of the cooler even when the frequency of resonant vibration is changed up to 87% from its initial frequency.     

An alternative method for evaluating congruence coefficients with Procrustes rotation: A bootstrap procedure.

Comparing factor structures across samples has long been an important topic in psychological research. Traditionally, the congruence coefficient is used to measure the degree of similarity between 2 factor matrices. However, as the congruence coefficients do not have known sampling distributions, it is difficult to assess factor replicability statistically. In this study, a bootstrap procedure was proposed to test factor invariance by examining the statistical significance of 3 types of congruence coefficients. A Monte Carlo study evaluated the performance of the proposed bootstrap procedure. Results provide strong support for this procedure as a powerful tool to assess factor replicability across groups. Two real examples demonstrate the usefulness of the proposed method. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rheology and Relationship among Rheological Parameters of Cross-Linked Waxy Maize Starch Dispersions Heated in Fructose Solutions

ABSTRACT: Dispersions of 5% cross‐linked waxy maize starch heated in Newtonian aqueous fructose solutions, 0 to 600 g per kg, exhibited either thixotropic or antithixotropic flow behavior, and viscoelastic behavior. The mean starch granule dia in the dispersions changed slightly with fructose content. Values of G' of the dispersions were higher than those of G', reflecting gel‐like behavior of the dispersions. Values of the first normal stress coefficient predicted from dynamic rheological and apparent viscosity data based on the Goddard‐Miller model were in reasonable agreement with experimental values.     

Identification of novel compositions of ferromagnetic shape-memory alloys using composition spreads

Exploration of new ferroic (ferroelectric, ferromagnetic or ferroelastic) materials continues to be a central theme in condensed matter physics and to drive advances in key areas of technology. Here, using thin-film composition spreads, we have mapped the functional phase diagram of the Ni-Mn-Ga system whose Heusler composition Ni(2)MnGa is a well known ferromagnetic shape-memory alloy. A characterization technique that allows detection of martensitic transitions by visual inspection was combined with quantitative magnetization mapping using scanning SQUID (superconducting quantum interference device) microscopy. We find that a large, previously unexplored region outside the Heusler composition contains reversible martensites that are also ferromagnetic. A clear relationship between magnetization and the martensitic transition temperature is observed, revealing a strong thermodynamical coupling between magnetism and martensitic instability across a large fraction of the phase diagram.