Effect of Co Substitution and Thermo-Magnetic Treatment on the Structure and Induced Magnetic Anisotropy of Fe84.5−xCoxNb5B8.5P2 Nanocrystalline Alloys

In the present work, we investigated in detail the thermal/crystallization behavior and magnetic properties of materials with Fe84.5-xCoxNb5B8.5P2 (x = 0, 5, 10, 15 and 20 at.%) composition. The amorphous ribbons were manufactured on a semi-industrial scale by the melt-spinning technique. The subsequent nanocrystallization processes were carried out under different conditions (with/without magnetic field). The comprehensive studies have been carried out using differential scanning calorimetry, X-ray diffractometry, transmission electron microscopy, hysteresis loop analyses, vibrating sample magnetometry and Mössbauer spectroscopy. Moreover, the frequency (up to 300 kHz) dependence of power losses and permeability at a magnetic induction up to 0.9 T was investigated. On the basis of some of the results obtained, we calculated the values of the activation energies and the induced magnetic anisotropies. The X-ray diffraction results confirm the surface crystallization effect previously observed for phosphorous-containing alloys. The in situ microscopic observations of crystallization describe this process in detail in accordance with the calorimetry results. Furthermore, the effect of Co content on the phase composition and the influence of annealing in an external magnetic field on magnetic properties, including the orientation of the magnetic spins, have been studied using various magnetic techniques. Finally, nanocrystalline Fe64.5Co20Nb5B8.5P2 cores were prepared after transverse thermo-magnetic heat treatment and installed in industrially available portable heating equipment.

Crystallization Effect of Television Broadcasts on Nigerian Voters During a Presidential Election

Television is popularly used to offer information to viewers during elections. There will always be citizens who register to participate in an election and then refuse to take further steps, like casting their votes. This study sought to find out if television broadcasts made citizens like these experience the crystallization effect. This effect causes uninterested citizens to make crystal clear choices on particular contestants. This study sought to find out about the crystallization effect on voters in Ado Odo/Ota communities in Ogun State of Nigeria during the 2007 Nigerian presidential election. The survey method was used to get required data from 782 respondents who were not members of any political party, had no candidate preference, and were yet to decide on who to vote for in this election. It seems plain from this study that television broadcasts sharpened these citizens' decisions to make specific choices. These undecided, indifferent, or neutral voters had their ideas crystallized or decisively formed to vote for specific candidates after exposure to television broadcasts.

Strategy for Polymorphic Control by Enzymatic Reaction and Antisolvent Crystallization: Effect of Aminoacylase on Metastable β-Glycine Formation

Although the enantioselective resolution by aminoacylase has been established for a long time, the effect of aminoacylase on the amino acid polymorphism is still unclear. To explore whether the presence...

The Application of ATD and DSC Methods to Study of the EN AC-48000 Alloy Phase Transformations

Tests concerning EN AC 48000 (AlSi12CuNiMg) alloy phase transition covered (ATD) thermal analysis and (DSC) differential scanning calorimetry specifying characteristic temperatures and enthalpy of transformations. ATD thermal analysis shows that during cooling there exist: pre-eutectic crystallization effect of Al9Fe2Si phase, double eutectic and crystallization α(Al)+β(Si) and multi-component eutectic crystallization. During heating, DSC curve showed endothermic effect connected with melting of the eutectic α(Al)+β(Si) and phases: Al2Cu, Al3Ni, Mg2Si and Al9Fe2Si being its components. The enthalpy of this transformation constitutes approx. +392 J g-1. During freezing of the alloy, DSC curve showed two exothermal reactions. One is most likely connected with crystallization of Al9Fe2Si phase and the second one comes from freezing of the eutectic α(Al)+β(Si). The enthalpy of this transformation constitutes approx. -340 J g-1. Calorimetric test was accompanied by structural test (SEM) conducted with the use of optical microscope Reichert and scanning microscope Hitachi S-4200. There occurred solution’s dendrites α(Al), eutectic silicon crystal (β) and two types of eutectic solution: double eutectic α(Al)+β(Si) and multi-component eutectic α+AlSiCuNiMg+β.

Crystallization Behavior of Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate) with WS2 as Nucleating Agent

Poly (3-hydroxybutyrate-co-hydroxyvalerate) (PHBV) is one of the aliphatic polyesters that are completely synthesized by microorganisms. Owing to the physical and chemical properties of PHA being similar with those of polypropylene, PHBV is expected to be able to partially replace petroleum-based polymers, and to reduce the pollution of environment at the same time. However, many inherent defects, including slow crystallization rate, large-size spherulite and secondary crystallization phenomenon, restrict the development of PHBV. In the present study, PHBV/WS2 hybrid materials where the tungsten disulphide (WS2) acted as nucleating agent were produced, and then its accelerated crystallization effect on PHBV was evaluated. Mo’s methods were employed to describe the non-isothermal crystallization kinetics of the nucleated PHBV hybrid materials. The activation energy (ΔE) of hybrid material was calculated by Kissinger formula. It was found that the addition of low WS2 loadings strongly increased the crystallization rate of PHBV and correspondingly the crystallization half time (t1/2) decreased from 97s to 38s with only 1wt.% WS2 added. Meanwhile, the crystallization temperature (Tc) increased from 81.9°C to 112 °C. The results reported here are expected to be of great interest for the practical application of PHBV.