Authors:M. Turco, G. Bagnasco, G Russo, P. Ciambelli, P. Patrono, M. A. Massucci, and S. Vecchio
The ion exchange technique was employed for the preparation of VO2+ modified titanium phosphates as catalysts for the selective reduction of NO with NH3. The samples were prepared by contacting with a vanadyl sulphate solution different precursor materials, amorphous, crystalline or sodium half exchanged titanium phosphate. The vanadium contents of modified phosphates were in the range 0.08–2.3 wt%. XRD and thermal analysis TG/DTA showed that vanadium loading does not cause structural modification in hydrogen titanium phosphate. A vanadyl containing phase was obtained when half sodium titanium phosphate was employed. The NH3 TPD measurements indicated the presence of a wide distribution of NH3 adsorbing sites with medium-high strength. Catalytic activity measurements were performed under dilute conditions. It was found that the presence of vanadium even in low amounts strongly promote the catalytic activity.
Authors:G. Klunder, J. Andrews, M. Church, J. Spear, R. Russo, P. Grant, and B. Andresen
Capillary electrophoresis has been used to separate metal ions characteristically associated with nuclear fission. Electrokinetic
injections and transient isotachophoretic techniques were employed to increase sample loading and provide on-column concentration
of the analyte. On-line concentration factors of approximately 700-fold have been achieved. Indirect-UV absorbance, on-line
radioactivity, and indirect laser-induced fluorescence detection were used to monitor analytes of interest. The radioactivity
detector consists of a plastic scintillator and photomultiplier tube with a 4π detection geometry. The efficiency was determined
to be approximately 80%, enabling samples resident in the detector window for 0.1 minutes to be reliably assayed. Detection
of152Eu and137Cs was achieved at the low nCi level. Indirect fluorescence was performed with quinine sulfate as the background fluorophor
with α-hydroxysobutyric acid added as a complexing agent. An argon ion laser was used as the excitation source with a diode
array detector. Limits of detection for La3+, Ce3+, Pr3+, Nd3+, Sm3+, and Eu3+ were determined to be in the sub — 10 ppb range (6–11 nM) with indirect laser-induced fluorescence detection.
Authors:S. Casu, S. Galvagno, A. Calabrese, G. Casciaro, M. Martino, A. Russo, and Sabrina Portofino
Summary Refuse derived fuels (RDF) characterization and pyrolysis behaviour, carried out by means of thermogravimetric analysis, infrared and mass spectroscopy, are presented. Thermal degradation of RDF takes place through three main mass loss stages; the analyses of evolved gas allow us to discriminate the contributions of the different fractions (paper, LDPE, wood, rubber, etc.) to the global decomposition. Furthermore thermogravimetry (TG) was used for the determination of kinetic parameters, using the differential method. In order to set up the conditions of production of a good quality pyrolysis gas, the operating conditions of RDF in a pyrolysis reactor have been simulated. Data show that the volatile fraction grows with the temperature, together with the relative conversion, and that light volatile fraction (hydrogen, ethyne, etc.) gets richer, at the expense of superior homologous hydrocarbons.
Authors:T. Prettyman, C. Cooper, P. Luke, P. Russo, M. Amman, and D. Mercer
A physics-based approach to gamma-ray response-function generation is presented in which the response of CdZnTe detectors
is modeled from first principles. Numerical modeling is used to generate response functions needed for spectrum analysis for
general detector configurations (e.g., electrode design, detector materials and geometry, and operating conditions). With
numerical modeling, requirements for calibration and characterization are significantly reduced. Elements of the physics-based
model, including gamma-ray transport, charge carrier drift and diffusion, and circuit response, are presented. Calculated
and experimental gamma-ray spectra are compared for a coplanar-grid CdZnTe detector.
Authors:D. Champion, C. Loupiac, D. Russo, D. Simatos, and J. M. Zanotti
This work was undertaken to investigate thermal and dynamic transitions observed in the temperature range close to the bulk ice melting temperature in sucrose solutions. Measurements of thermal (differential calorimetry) and dynamic (neutron scattering) properties were compared in order to give a physical interpretation of the thermal transitions observed during the thawing of amorphous sucrose solutions. In fact, the freezing of biological material leads to the distinction between different pools of water: bulk water which becomes ice after freezing, unfrozen water trapped in the glassy matrix or close to the interface of solutes can be considered, and finally freezable confined water with a lower melting point than bulk water and with properties depending on both the ice presence and the microstructure of the material. The transition temperatures such as glass transition or melting are dependent on the freezing protocol used and examples of annealing effects are presented, in order to underline the necessity of a good temperature control during freezing for the study of biological material with freezable water.