Anticipating stochastic differential systems with memory

This article establishes existence and uniqueness of solutions to two classes of stochastic systems with finite memory subject to anticipating initial conditions which are sufficiently smooth in the Malliavin sense. The two classes are semilinear stochastic functional differential equations (sfdes) and fully nonlinear sfdes with a sublinear drift term. For the semilinear case, we use Malliavin calculus techniques, existence of the stochastic semiflow and an infinite-dimensional substitution theorem. For the fully nonlinear case, we employ an anticipating version of the Itô–Ventzell formula due to Ocone and Pardoux [D. Ocone, E. Pardoux, A generalized Itô–Ventzell formula. Application to a class of anticipating stochastic differential equations, Annales de l’Institut Henri Poincaré. Probabilité s et Statistiques 25 (1) (1989) 39–71]. In both cases, the use of Malliavin calculus techniques is necessitated by the infinite dimensionality of the initial condition.     

Optimization approaches of aircraft flight path reducing noise: Comparison of modeling methods

An optimization model of flight paths is designed for minimizing aircraft noise at reception points around airports. It is stated as a nonconvex and nonlinear control problem governed by ordinary differential equations using a jet noise model. The vertical plan and the space cases have been solved using two approaches, one direct and one indirect. The objective was initially to apply these two methods, then to carry out comparisons, and finally to retain the method which would be applied for the general case including engine and airframe sources. Results showed that the direct method is adapted for solving the problem and can be implemented with moderate computing times. It is sufficient to analyze the constrained flight path optimization of commercial aircraft reducing noise levels. The three-segment approach procedure has been obtained as an optimized flight path which can substantially reduce noise levels. This modified approach procedure has been examined and could benefit both airlines and communities.     

Experimental Investigation of Pure Spinel Mn3O4 Properties Synthesized through Chemical Spray Pyrolysis for Future Gas Sensor Application

The semiconductor realization is a very significant stage in gas sensor application. Herein, the Mn₃O₄ semiconductor was deposited using chemical spray pyrolysis. The effect of deposition temperature on structural, vibrational optical and electrical Mn₃O₄ thin layers properties were investigated through: X-ray diffraction, Raman spectroscopy, UV-visible spectrophotometer, and two points electrometers respectively. The X-ray diffraction showed the appearance of spinel phase of tetragonal Mn₃O₄ with strong formation direction along (101) plan and without any secondary phase indicating the formation of pure Mn₃O₄. The Raman spectroscopy confirmed the results obtained in XRD and certified the high-quality formation of Mn₃O₄. In addition, the crystallinity improvement (the increase of crystallite size and the decrease of dislocation density) was caused by the increasing of deposition temperature from 350 °C to 450 °C. Optical properties such as transmittance, absorbance and band gap energy were extracted by UV-Visible spectrophotometer. Thus, low transmittance, high absorbance and small band gap energy were observed at the highest substrate temperature (450 °C). The electrical conductivity showed good values between 4.83 and 13.89 mS.cm⁻¹. These properties make Mn₃O₄ an appropriate material to be used as a sensitive layer in gas sensors applications.     

Pyridazine,oxazine, pyrrole,and pyrrolo[1,2‐a]quinazoline derivatives from malononitrile dimer

2‐Amino‐1,1,3‐tricyano‐3‐bromopropene was obtained from bromination of 2‐amino‐1,1,3‐tricyanopropene (malononitrile dimer) with N‐bromosuccinimide. This bromo derivative reacts with hydrazine hydrate, phenyl hydrazine, and hydroxylamine hydrochloride to afford pyridazine and oxazine derivatives, respectively. In base‐catalyzed reactions with primary aromatic amines and anthranilic acid derivatives, it produces N‐aryl pyrrol‐3,5‐dicarbonitrile and pyrrolo[1,2‐a]quinazolin‐5‐imine, or pyrrolo[1,2‐a]quinazolin‐5‐one derivatives, respectively. The structures of the newly synthesized heterocycles were established on the basis of elemental analyses and spectral data. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:612–616, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10199     

Physical aging phenomena in silica and glass beads filled elastomers (EPDM)

The physical aging concept is generally used to explain the typical behavior of amorphous glassy materials such as amorphous polymers. It can be easily evidenced by measuring the effect of a static deformation on the dynamic mechanical properties. In this paper, an attempt is made to determine the “glassy” behavior of elastomeric EPDM chains when they are confined in the vicinity of the filler (glass beads, silicas) surface. It is demonstrated that glassy behavior and physical aging phenomena are detected even with a filled elastomer. Furthermore, the influence of the filler volume fraction, the filler nature and of filler surface treatments with silanes were studied. Finally, an original attempt is made to explain filler-rubber reinforcement by a kind of bimodal network created from linkages between a densely packed interfacial region and the outer loose matrix.     

Functionally substituted alkylbenzotriazoles: Reactivity of alkylbenzotriazoles toward electrophilic and nucleophilic reagents

The reactivity of benzotriazolylacetone toward a variety of carbon and nitrogen electrophiles is reported. Several novel azolylbenzotriazoles as well as benzotriazolyl‐cinnolines have been synthesized. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:141–145, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10009     

Spline quasi-interpolation in the Bernstein basis and its application to digital elevation models

A nonstandard low-cost spline approximation method for approximating bivariate functions is constructed. It is applied for Digital Elevation approximation and then its accuracy in the downscaling process is studied.     

Study of the migration of additives from plasticized PVC

The aim of this paper is to study the interactions between packaging and food. For that purpose, additives were first characterized. Kinetic studies of their specific migrations have been carried out by using different analytical methods such as gas chromatography, Fourier transform infrared spectroscopy, atomic absorption spectrometry and differential scanning calorimetric analysis. The influence of various parameters such as temperature, agitation, nature of food simulant and initial concentration of plasticizer was considered.     

Supramolecular Thermotropic Liquid Crystalline Materials with Nematic Mesophase Based on Methylated Hyperbranched Polyethylenimine and Mesogenic Carboxylic Acid

Summary: Supramolecular interaction of fully methylated hyperbranched polyethylenimines (PEI) with a mesogen‐based carboxylic acid, 5‐(p‐cyanobiphenoxy)pentanoic acid, results in the formation of supramolecular complexes exhibiting thermotropic liquid crystalline (LC) mesophases. In contrast to the common smectic mesophases of most dendritic LC polymers, nematic LC phases were observed. The complexation of PEI and the mesogen units is due to electrostatic interaction between the carboxylate groups and the ammonium end groups of PEI. LC properties were investigated by a combination of differential scanning calorimetry, polarizing light optical microscopy, and X‐ray diffractometry.

Schematic illustration of the supramolecular assembly of CBPA with PEIMe backbone.