Interfacial Solute Segregation in the Thermally Grown Oxide of Thermal Barrier Coating Structures

Atom probe tomography is used to measure interfacial and grain boundary segregation in the thermally grown oxide layers found on thermal barrier coatings formed by isothermal heat treatments at 1,100 °C. Segregation of Zr, Hf, Y, and minor elements at the metal/oxide interfaces, oxide grain boundaries and oxide dislocations are observed, quantified and rationalised. The implications of the findings are discussed.     

Optimization of a DNA Nicking Assay to Evaluate Oenocarpus bataua and Camellia sinensis Antioxidant Capacity

This study was aimed at assessing the DNA damage protective activity of different types of extracts (aqueous, methanolic and acetonic) using an in vitro DNA nicking assay. Several parameters were optimized using the pUC18 plasmid, especially FeSO₄, EDTA, solvent concentrations and incubation time. Special attention has been paid to removing the protective and damaging effect of the solvent and FeSO₄ respectively, as well as to identifying the relevant positive and negative controls. For each solvent, the optimal conditions were determined: (i) for aqueous extracts, 0.33 mM of FeSO₄ and 0.62 mM of EDTA were incubated for 20 min at 37 °C; (ii) for acetone extracts, 1.16% solvent were incubated for 15 min at 37 °C with 1.3 mM of FeSO₄ and 2.5 mM of EDTA and (iii) for methanol extracts, 0.16% solvent, were incubated for 1.5 h at 37 °C with 0.33 mM of FeSO₄ and 0.62 mM of EDTA. Using the optimized conditions, the DNA damage protective activity of aqueous, methanolic and acetonic extracts of an Amazonian palm berry (Oenocarpus bataua) and green tea (Camellia sinensis) was assessed. Aqueous and acetonic Oenocarpus bataua extracts were protective against DNA damage, whereas aqueous, methanolic and acetonic extracts of Camellia sinensis extracts induced DNA damage.     

Positive contrast with therapeutic iron nanoparticles at 4.7 T

Object  

The purpose of the study was to show the feasibility of a positive contrast technique GRadient echo Acquisition for Superparamagnetic particles with Positive contrast (GRASP), for a specific type of magnetic particles, designed for tumor treatment under MRI monitoring.     

Fluorescence spectroscopy as a non invasive tool to follow in situ the polymerization in miniemulsion

Miniemulsion polymerization is a powerful technique to produce a whole variety of latexes with controlled colloidal and chemical properties, which has gained an increasing importance in the past years. For many applications, the following of the kinetics of polymerization is of crucial importance. In this study, we developed a technique based on the use of fluorescent probes that could be a very promising noninvasive method to follow the reaction in situ. It was possible to follow qualitatively the kinetics of methyl methacrylate (MMA) polymerization by measuring the photophysical properties of fluorescent probes sensitive to the modification of the viscosity of the microenvironment along the reaction course. Two fluorescent sensors have been considered: 1,1‐dicyano‐4‐(4′‐dimethylaminophenyl)‐1,3‐butadiene) and pyrene. In this article, we will show that using these two different fluorescent probes allow the detection of MMA polymerization in miniemulsion. The results will be compared with a classical NMR method. This method could be easily adapted to different monomers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Corrosion Performance Based on the Microstructural Array of Al-Based Monotectic Alloys in a NaCl Solution

The aim of this study is to compare the electrochemical behavior of three monotectic Al-based alloys (Al-Pb, Al-Bi, and Al-In) in a 0.5 M NaCl solution at room temperature. Two distinct microstructure arrays were experimentally obtained for each Al monotectic alloy by using a water-cooled unidirectional solidification system. Results of electrochemical impedance spectroscopy (EIS) plots, potentiodynamic polarization curves, and impedance parameters obtained by an equivalent circuit analysis are discussed. It was found that the Al-Pb alloy has lower corrosion current density, higher polarization resistance, lower relative weight, and cost than the corresponding values of Al-Bi and Al-In alloys. It is also shown that the electrochemical behavior of the three alloys examined are intimately correlated with the scale of the corresponding microstructure, with smaller droplets and spacings (i.e., cell and interphase spacings) being associated with a decrease in the corrosion resistance.     

A comparison and joint use of NIR and MIR spectroscopic methods for the determination of some parameters in European Emmental cheese

The determination of winter cheese chemical properties, namely, fat, sodium chloride (NaCl), pH, non protein nitrogen (NPN), total nitrogen (TN) and water soluble nitrogen (WSN) was done using spectroscopic technologies with different wavelength zones. The Emmental cheeses provided from different European countries were studied. A total of 91 cheeses produced during the winter time in Austria (n=4), Finland (n=6), Germany (n=13), France (n=30) and Switzerland (n=38) were analysed by near infrared (NIR) and mid infrared (MIR) spectroscopies. The combination of these two spectral regions (sum of their spectra) was also studied. The partial least square (PLS) regression with the leave one-out cross validation technique was used to build up calibration models using data set designated as calibration set. These models were validated with another data set designated as validation set. The obtained results suggest the use of the NIR for the determination of fat and TN contents, and the MIR for NaCl and NPN contents as well as for the pH. Similar results were obtained for WSN using the two techniques together. The combined spectra of both NIR and MIR did improve the results, while providing comparable results to those obtained from either the NIR or MIR spectroscopy.     

RF transceiver and transmission line behavioral modeling in VHDL-AMS for wired RFNoC

Despite the exceptional progress of MPSoC architectures, on chip communication networks remain a lock for the evolution of their performances due to the power consumption and the delay in data carrying. In this context, the wired radio frequency (RF) network on chip (RFNoC) has emerged. In this paper, we developed a library of RF component models in VHDL-AMS for time domain simulation. This library includes mainly the transmission line (TL) and the RF transceiver components such as the low noise amplifier (LNA), the mixer and the local oscillator (LO). The models consider the conventional parameters describing their performances including the non-linearities, the noise and the bandwidth of the LNA and the mixer. Leakages between ports are also considered for the mixer. The LO model considers the traditional parameters, more importantly its phase noise. The originality of the TL model is the modeling of the skin effect on a wide frequency range for time domain simulations. All the models are validated. Global simulations are performed to demonstrate the interest to accurately model the components of the RFNoC. The developed library is used here for wired RFNoC, however it can be used for all other wired and wireless RF communication system.