Set point identification of a tribocharging process for mixed granular solids

Identification of the optimal operating conditions is a critical issue for the industrial application of tribocharging techniques. The aim of this paper is to formulate a set of recommendations regarding the choice of tray length, vibration amplitude and material feed-rate values for a vibratory-type tribocharger. The study was carried out on a laboratory vibratory feeder with granular plastics originating from waste electrical and electronic equipment. Several one-factor-at-a-time experiments followed by a composite factorial experiment were performed based on a two-step strategy: 1) identifying the domain of variation of the controlled variables; 2) finding the best choice of the set point.     

A Convenient Route to Norpyrenophorin

A norpyrenophorin precursor has been achieved by a three-step synthesis in good yield.     

Caps and Colouring Steiner Triple Systems

Hill [6] showed that the largest cap in PG(5,3) has cardinality 56. Using this cap it is easy to construct a cap of cardinality 45 in AG(5,3). Here we show that the size of a cap in AG(5,3) is bounded above by 48. We also give an example of three disjoint 45-caps in AG(5,3). Using these two results we are able to prove that the Steiner triple system AG(5,3) is 6-chromatic, and so we exhibit the first specific example of a 6-chromatic Steiner triple system.     

Comparison of fuzzy numbers using a fuzzy distance measure

A new approach for ranking fuzzy numbers based on a distance measure is introduced. A new class of distance measures for interval numbers that takes into account all the points in both intervals is developed first, and then it is used to formulate the distance measure for fuzzy numbers. The approach is illustrated by numerical examples, showing that it overcomes several shortcomings such as the indiscriminative and counterintuitive behavior of several existing fuzzy ranking approaches.     

Reversible addition–fragmentation chain transfer polymerization of methyl methacrylate in suspension

The reversible addition–fragmentation chain transfer polymerization of methyl methacrylate mediated by 2‐cyanoprop‐2‐yl dithiobenzoate (CPDB) in bulk (60 and 70 °C) and suspension (70 °C) was studied, and in both polymerization systems, a good control of the molecular weight and polydispersity was observed. Stable suspension polymerizations were carried out over a range of CPDB concentrations, and with increasing CPDB concentration, the particle size and polydispersity index of the produced polymer decreased. The former was ascribed to the lower viscosities of the monomer and polymer droplets at low conversions, which caused easier breakup with the applied shear stresses. Lower polydispersity indices at higher CPDB concentrations were probably caused by a diminished gel effect, which was observed at lower CPDB concentrations at high conversions, causing a broadening of the molecular weight distribution. The livingness of the polymers formed in suspension was proven by successful chain extensions with methyl methacrylate, styrene, and 2‐hydroxyethyl methacrylate. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2001–2012, 2005     

Minimal Penalties for Gaussian Model Selection

This paper is mainly devoted to a precise analysis of what kind of penalties should be used in order to perform model selection via the minimization of a penalized least-squares type criterion within some general Gaussian framework including the classical ones. As compared to our previous paper on this topic (Birgé and Massart in J. Eur. Math. Soc. 3, 203–268 (2001)), more elaborate forms of the penalties are given which are shown to be, in some sense, optimal. We indeed provide more precise upper bounds for the risk of the penalized estimators and lower bounds for the penalty terms, showing that the use of smaller penalties may lead to disastrous results. These lower bounds may also be used to design a practical strategy that allows to estimate the penalty from the data when the amount of noise is unknown. We provide an illustration of the method for the problem of estimating a piecewise constant signal in Gaussian noise when neither the number, nor the location of the change points are known.     

Nitridophosphate-Based Ultra-Narrow-Band Blue-Emitters: Luminescence Properties of AEP8N14:Eu2+ (AE=Ca,Sr, Ba)

The nitridophosphates AEP₈N₁₄ (AE=Ca, Sr, Ba) were synthesized at 4–5 GPa and 1050–1150 °C applying a 1000 t press with multianvil apparatus, following the azide route. The crystal structures of CaP₈N₁₄ and SrP₈N₁₄ are isotypic. The space group Cmcm was confirmed by powder X-ray diffraction. The structure of BaP₈N₁₄ (space group Amm2) was elucidated by a combination of transmission electron microscopy and diffraction of microfocused synchrotron radiation. Phase purity was confirmed by Rietveld refinement. IR spectra are consistent with the structure models and the chemical compositions were confirmed by X-ray spectroscopy. Luminescence properties of Eu²⁺-doped samples were investigated upon excitation with UV to blue light. CaP₈N₁₄ (λ_em=470 nm; fwhm=1380 cm⁻¹) and SrP₈N₁₄ (λ_em=440 nm; fwhm=1350 cm⁻¹) can be classified as the first ultra-narrow-band blue-emitting Eu²⁺-doped nitridophosphates. BaP₈N₁₄ shows a notably broader blue emission (λ_em=417/457 nm; fwhm=2075/3550 cm⁻¹).     

Numerical design of a Knudsen pump with curved channels operating in the slip flow regime

A numerical procedure has been developed for modeling 2D thermal creep flows with Fluent^®. Complete first order velocity slip, including thermal creep and walls curvature effects, as well as temperature jump, boundary conditions, are implemented via C routines. After validation on benchmark flows, the technique is used for designing a Knudsen pump with curved microchannels and it is demonstrated that this micropump can be efficient in the slip flow regime.     

One step continuous hydrothermal synthesis of very fine stabilized superparamagnetic nanoparticles of magnetite

Stable suspensions of citrated SPIO nanoparticles were synthesised in one step using a hydrothermal continuous process. Citrates control the crystallite size and the oxidation degree of metallic ions despite the very short reaction time (4 s). Magnetite particles, Fe(2.94)O(4), with an average size of 4 nm and good monodispersity were obtained.