BPA in Baby Feeding PET Bottle, Aluminium Can and Thermal Printed Paper: Application of Acridine Orange Oxidation Inhibition Method to Estimate BPA

The leaching of Bisphenol-A (BPA) from plastic baby feeding bottles, aluminium cans and thermal printed receipts was investigated under aquatic condition at high temperature. Leached BPA was analysed using UV-Visible Spectrophotometer based on inhibitory effect of BPA on acridine orange oxidation, as a function of change in temperature and time of contact of water with the samples. Proposed method of BPA estimation method does not require any extraction and/or derivatization. The detection limit of BPA under current experimental setup was 0.1 ng/ml. The results of BPA leached from baby feeding PET bottles, aluminium can with epoxy resin lining and thermal paper were 87 ± 10 ng/bottles, 68 ± 5 ng/bottle and 110 ± 15 ng/receipt under the current experimental conditions.

Thermal behaviour of stevensite at temperatures up to 800°C.

Stevensite is a Mg-trioctahedral smectite with layer charge stemming from vacancies in the octahedral sheet. In the present work we studied the thermal behavior of Jbel Ghassoul stevensite from Morocco, known as Ghassoulite or Rhassoulite, free of talc layers. The clay fraction of the material was separated by sedimentation, it was subsequently heated from 250° to 800° C and the end products were examined with X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy. The influence of heating on the stevensite structure begins at 400°C and is completed at 500°C. It involves irreversible collapse of the layers at ~10Å, which do not re-expand in ethylene glycol (EG) vapors. In contrast, heating at lower temperatures does not affect the stevensite layers, which expand completely in EG. The FTIR spectra indicate the formation of talc-like (kerolite) layers after heating at temperatures exceeding 400°C. Within the current experimental setup, the transition to kerolite layers takes place without the formation of an intermediate mixed-layer stevensite/talc phase. Heating at higher temperatures does not change the transformation pattern, until 800°C where complete dehydroxylation of the 2:1 layer takes place, which is associated with the formation of enstatite. The results of this study clearly demonstrate that opposite to common trioctahedral and dioctahedral smectites, stevensite converts to another layer silicate prior to dehydroxylation.

Magnetization Method Design of Bulk Multi-Seeded High Temperature Superconductors

The potential application of bulk high temperature superconductor (HTS) magnets has attracted much attention because of the potential high trapped flux in HTS magnets. This paper focuses on the magnetization method design of bulk multi-seeded HTS magnets for obtaining their better flux-trapping performance. Firstly, three different magnetization methods were carried out based on the current experimental setup to find a better way of magnetizing a bulk melt-texture three-seeded YBaCuO superconductor. The experimental results indicated that when the three domains of this three-seeded YBaCuO bulk were magnetized in order, the maximum trapped flux was higher than that when only one domain was magnetized. However, this method costs about three times of the magnetization time than the other two methods and the increasing ratio was only about 11.11%. It has been found that another method of magnetizing only the middle domain could also get a good result such as the uniformity of trapped flux is good. In order to improve the current experimental magnetization conditions for further improvement, two sheets of iron were designed to attach two poles of the electromagnet (Lakeshore, Model EM4-CV) for increasing the magnetizing area, and that all domains of a bulk multi-seeded HTS can be magnetized in one time. Firstly, the appropriate size and thickness of the iron sheets was simulated and optimized by Comsol Multiphysics. It has been found that the magnetic field between two poles was highest when the thickness of iron was 2 mm and the length was 68 mm. Then, the simulating and optimization results had been verified by the following experiments. According to the comparison experiments, it is proved that to choose the magnetization method that only magnetizing the middle domain with the improved setup is helpful to obtain larger and more homogeneous magnetic flux for the bulk multi-seeded HTS magnet due to the added iron sheets.