Authors:N. van der Meulen, G. Steyn, T. van der Walt, F. Szelecsényi, Z. Kovács, and H. Raubenheimer
The production of 133Ba via the nuclear reaction 133Cs(p,n)133Ba on targets of CsF and CsCl has been investigated. Two methods to quantitatively separate 133Ba from the Cs target material, using AG 50W-X4 and AG MP-50 cation exchange resins, respectively, have been developed. Measured
thick-target yield values are presented and some characteristics of the underlying excitation function have been inferred.
For this purpose, calculations using the Geometry Dependent Hybrid model, as implemented in the code ALICE-IPPE, have been
performed. Aspects of the production targetry developed as part of this study are also discussed.
Mn-nodule is one of the most important deep sea mineral resources to be explored and exploited in the next century. Analytical quality control based on this kind of Certified Reference Materials (CRMs) is therefore necessay. In the present work, nearly 30 elements in two Chinese Mn nodule Reference Materials (RMs), GSPN-2 and GSPN-3, were determined using extendedK0-relative comparison NAA technique, developed in our laboratory. The unique features of this work include; (1) high accuracy obtained by the interal validation function of our technique; (2) extensive determinable elements obtained by the hybrid nature of our software and (3) neutron flux self-shielding corrections.
Authors:Sangram Samal, Elizabeth Fernandes, Federica Chiellini, and Emo Chiellini
In the present study polymeric membranes consisting of poly(vinyl alcohol) (PVA) and multi-walled carbon nanotubes (MWCNTs)
were prepared by casting method and their morphological, thermal and de-swelling behaviour were characterized. The effect
of MWCNTs in the hybrid membranes was more significant when its concentration was high. The thermo degradation (Td) and crystallization (Tc) temperatures of PVA increased of 10 and 9 °C, respectively in presence of 50 × 10−2 w v−1% of MWCNTs (PVNT3). Besides, the amount of non-free water increases with increasing of MWCNTs probably due to a capillary
Excitation functions for the production of198mAu,198Au,198(m+g)Au, by (, 2pn) reactions on gold and isomeric ratios for198Au were determined experimentally. The method of activation of metallic foils was employed. The irradiations were performed in the isochronous cyclotron at Karlsruhe (Germany) with -particles at 90 MeV. Gamma-spectrometry by means of an intrinsic Ge detector was used to determine the nuclides produced. In addition, a comparison between the cross sections obtained and a calculation using the hybrid model of pre-equilibrium reactions, in combination with the statistical model development by ERNST is presented.
Most studies report a depression of the glass transition temperature in thin polymer films. To gain insight into this behavior,
we have simultaneously investigated the structure of materials and their thermal behavior by developing an ATR–FTIR–nano-differential
scanning calorimeter (nanoDSC) hybrid instrument consisting of a ZnSe ATR crystal upon which the sample and a DSC-on-a-chip
rests. FTIR spectra showed property changes with film thickness; nanoDSC did not. The relative absorbance of an IR peak at
797 cm−1 was found to correlate with aging time in thin films, suggesting that conformational structure of thin films is critical
to their thermal behavior.
Authors:G. Bannach, R. Arcaro, D. Ferroni, A. Siqueira, O. Treu-Filho, M. Ionashiro, and E. Schnitzler
Thermogravimetry (TG), differential thermal analysis (DTA), differential scanning calorimetry (DSC) as well as X-ray diffraction
powder (DRX) patterns and Fourier transformed infrared spectroscopy (FTIR) were used to study ketoprofen, ibuprofen, and naproxen.
The chemical or physical properties of the studied compounds were established and when possible by X-ray powder diffractometry
and/or infrared spectroscopy were used. In this investigation, quantum chemical approach was used to determine the molecular
structures using Becke three-parameter hybrid method and the Lee–Yang–Par (LYP) correlation functional. The performed molecular
calculations in this work were done using the Gaussian 03 routine. Theoretical calculations help in interpretations of FTIR
spectra supplying structural and physicochemical parameters.
Authors:Qiang Wu, Chuck Zhang, Richard Liang, and Ben Wang
Organic–inorganic hybrid composites of epoxy and phenyltrisilanol polyhedral oligomeric silsesquioxane (Ph7Si7O9(OH)3, POSS-triol) were prepared via in situ polymerization of epoxy monomers. The nanocomposites of epoxy with POSS-triol can
be prepared in the presence of metal complex latent catalyst, aluminum triacetylacetonate ([Al]) for the reaction between
POSS-triol and diglycidyl ether of bisphenol A (DGEBA). The dispersion morphology of organic–inorganic hybrid was characterized
by scanning electronic microscopy (SEM). The thermostability of composites was evaluated by thermal gravimetric (TG) analysis.
The flammability was evaluated by cone calorimeter test. The presence of [Al] latent catalyst leads to a decrease in combustion
rate with respect to epoxy and epoxy/POSS composites as well as reduction in smoke, CO and CO2 production rate. The effect of [Al] is to reduce the size of spherical POSS particles from 3–5 μm in epoxy/POSS to 0.5 μm
in epoxy/POSS[Al]. Furthermore, POSS with smaller size may form compact and continue char layer on the surface of composites
Authors:Stefan Kreibik, Virginia Coman, Constantin Măruțoiu, and Gheorghe Mihăilescu
Some of the physical properties of dielectric liquids are influenced by electric fields. Interesting results were obtained in this work by applying external alternating electric fields to chromatographic media (paper or TLC plates) filled with dielectric liquids. Capillary tubes were used to enable understanding of the flow phenomena which occur in porous media. It was observed that the displacement velocity of the liquids confined in the capillary tubes depended on the magnitude of the alternating electric field, the electric properties (conductivity, permittivity) of the liquids, the frequency of the current, the tube diameters, the shapes of the molecules, and the tube material. Evident electrokinetic effects (dielectroosmotic flow) were observed on silica gel layers and paper strips developed with non-polar and polar solvents. As a result the separation resolution of non-ionic compounds was improved. This method is a hybrid of electric forced flow and classical diffusion; we have named it planar dielectrochromatography.
Authors:Tian Weizhi, Ni Bangfa, Wang Pingsheng, and Nie Huiling
Certifications of trace elements in existing CRMs, especially biological CRMs, are far from satisfactory. Neutron activation analysis (NAA) for its inherent advantages combined with newly established parametric standardization, may contribute to improve this situation. The continuing progress of the hybrid extended k0-relative NAA technique developed in our laboratory is discussed. Examples are given to show the reliability of the method in certification of multielements. RNAA is still one of the best methods, or even the method of choice, in analysis at sub-g/g concentration levels. The suitability of the technique for this purpose has been studied through the determination of rare earth elements at ng/g concentration level in two Chinese biological CRMs using both RNAA and ICPMS. Sampling behaviors of multielements in CRMs have been studied by INAA in an effort to develop CRMs suitable for analysis with small sample sizes.
Valency control of neptunium is an important issue in the partitioning of high level liquid waste (HLLW) from power-reactor
spent fuel treatment. The redox behavior of neptunium in HLLW is quite different from that in nitric acid because of the effect
of the large amount of ions in HLLW. In order to remove neptunium from HLLW, we studied the reduction of neptunium in synthetic
HLLW (SHLLW) to maintain its valency at IV so that it can be extracted by TRPO extractant in the well developed Chinese TRPO
process. Five different reductants were tested and the reduction behavior was investigated. The influence of some active elements
in SHLLW was studied. The mechanism that the reductants react with neptunium through Fe element was supposed and proved by
experiments. The reduction rate of Np(V) was highly enhanced by Fe element. Finally, a hybrid reductant was suggested and
good reduction efficiency was obtained.