Fuzzy versus quantitative association rules: a fair data-driven comparison.

As opposed to quantitative association rule mining, fuzzy association rule mining is said to prevent the overestimation of boundary cases, as can be shown by small examples. Rule mining, however, becomes interesting in large databases, where the problem of boundary cases is less apparent and can be further suppressed by using sensible partitioning methods. A data-driven approach is used to investigate if there is a significant difference between quantitative and fuzzy association rules in large databases. The influence of the choice of a particular triangular norm in this respect is also examined.     

Crossflow microfiltration of gum arabic solutions: Comparison of the classical system with the co-current permeate flow system

Gum arabic is a natural gum exuded mainly by the trees Acacia senegal , currently used in the food industries for its emulsifying, thickening and stabilizing properties. Its present processing includes various operations providing a quite turbid product. Crossflow microfiltration could be interesting for the clarification and the cold-pasteurization of the gum arabic solutions. Several experiments were therefore made with the crossflow microfiltration unit at ENSIA, using two different systems: the classical one (without permeate circulation), and the co-current permeate flow system (CCPF) allowing the exploration of the low transmembrane pressures range. With gum arabic solutions of 0.17g solids g⁻¹ solution and 70°C, the best results after 60 min of filtration (105.7 L h⁻¹ m⁻², 4.4% of solids retention and 83.4% of clarification) were obtained with the CCPF system at low transmembrane pressure and high crossflow velocity (0.3 bar and 7.5ms⁻¹).     

Temperature-induced phase change in a fat. A study by electron spin resonance

Electron Spin Resonance, Differential Scanning Calorimetry and rheological techniques have been used to study the physical changes induced by temperature in lard and in the solid and liquid fractions obtained by fractionation of lard at 15 C. The mobilization process of a C18 fatty acid nitroxide derivative dispersed in the molten fat has been observed in the temperature range −50 to +70 C. The mobilization of the probe seemed to be concomitant with the melting of the low melting point glycerides. Above this temperature, all the probes were in the liquid phase and their mobility reflected the viscosity of their liquid environment, or the viscosity of the bulk fat when crystal was no longer present. Probe mobility was temperature dependent, and it was identical for the three fats at the same temperature, despite their different triglyceride compositions.     

Index of critical points in rational l-approximation

This article is concerned with the l²-approximation of a given transfer function f by a rational one whose order is prescribed. We show that the sum of the indices of the critical points of the criterion is generically equal to 1, and in particular does not depend on f.     

Microstructure and Mechanical Properties of Hot-Pressed Silicon Carbide-Aluminum Nitride Compositions

A flexural strength of up to 1 GPa was achieved in SiC-AIN materials and is attributed to a dense, equiaxial grain structure of the 2H(δ) SiC-AIN solid solution, with a relatively uniform grain size of ∼ 1 μm. The strength was found to decrease with increasing grain size. While the β→α phase transformation and the formation of various metastable polytypes make microstructural control difficult in SiC materials, excellent control is facilitated in SiC-AIN materials as a result of the stable 2H solid solution. Several mechanisms of grain refinement during the β→ 2H transition were observed, most notably the direct formation of several 2H grains from a single β grain. In addition, grain growth is limited by the diffusion-controlled nature of the transition. These mechanisms could be utilized to achieve even higher strength values, with potentially higher reliability of the materials in structural applications.     

Electrocatalytic oxidation of ethanol on Pt–Mo bimetallic electrodes in acid medium

Pt–Mo alloy electrocatalysts were prepared by an arc-melting furnace process to investigate the origin of their enhanced activity toward ethanol oxidation. Two Mo contents were chosen in zones of the binary phase diagram where they are supposed to form either a pure alloy mixture or a solid solution. Pt–Mo alloy catalysts were more active than Pt-alone. Gradual Mo dissolution at the electrode surface was observed after voltammetric and chronoamperometric measurements. The dissolved Mo contributed to the catalytic effect of the electrode as underpotentially deposited (upd) adatoms. This dissolution probably also leads to an increase in the electrode surface roughness. Low molybdenum content in the electrode material enhances the activity toward ethanol oxidation when compared to Pt-alone. Ethanol oxidation was also investigated by in situ infrared reflectance spectroscopy in order to determine the presence of adsorbed intermediates like CO species. Acetaldehyde, acetic acid and CO₂ were also found by spectroscopic experiments.     

Sol–Gel Processing and Microwave Characteristics of Ba(Mg⅓Ta⅔)O3 Dielectrics

The sol–gel method has been developed for the preparation of pure Ba(Mg_1/3Ta_2/3)O₃ ceramics. This involves the reaction of the heterometallic alkoxide Ta₂Mg(OEt)₁₂ with hydrated barium hydroxide Ba(OH)₂·8H₂O. Complete crystallization of the sol–gel-derived powder is achieved at 600°C, leading to a cubic perovskite type phase. After sintering at 1400°C (2–5 h), a trigonal cell arises from Mg–Ta ordering (the degree of order is greater than 0.9), and about 98.5% of the theoretical density is obtained. Preliminary microwave dielectric measurements show that the dielectric constant and the unloaded Q _u of the ceramics are 24.2 and 6750, respectively, at 7.7 GHz.     

Three‐Dimensional Printing of Multifunctional Nanocomposites: Manufacturing Techniques and Applications

The integration of nanotechnology into three‐dimensional printing (3DP) offers huge potential and opportunities for the manufacturing of 3D engineered materials exhibiting optimized properties and multifunctionality. The literature relating to different 3DP techniques used to fabricate 3D structures at the macro‐ and microscale made of nanocomposite materials is reviewed here. The current state‐of‐the‐art fabrication methods, their main characteristics (e.g., resolutions, advantages, limitations), the process parameters, and materials requirements are discussed. A comprehensive review is carried out on the use of metal‐ and carbon‐based nanomaterials incorporated into polymers or hydrogels for the manufacturing of 3D structures, mostly at the microscale, using different 3D‐printing techniques. Several methods, including but not limited to micro‐stereolithography, extrusion‐based direct‐write technologies, inkjet‐printing techniques, and popular powder‐bed technology, are discussed. Various examples of 3D nanocomposite macro‐ and microstructures manufactured using different 3D‐printing technologies for a wide range of domains such as microelectromechanical systems (MEMS), lab‐on‐a‐chip, microfluidics, engineered materials and composites, microelectronics, tissue engineering, and biosystems are reviewed. Parallel advances on materials and techniques are still required in order to employ the full potential of 3D printing of multifunctional nanocomposites.