Experimental and theoretical investigation of first hyperpolarizability in aminophenols

This work reports theoretical and experimental studies on the first hyperpolarizability (beta) of aminophenols, evaluating the influence of the NH(2) group position relative to the OH group on the hyperpolarizability. A new extension of hyper-Rayleigh scattering technique using picosecond pulse trains was employed to obtain the experimental absolute values of (beta). The theoretical static beta(0) values were calculated using AMI method implemented in the AMPAC program. The theoretical and experimental data show a clear dependence between beta and the relative position of the electron donor (D) and acceptor (A) groups, presenting the 2-aminophenol the higher values. Moreover, calculations show excellent qualitative agreement between theoretical and experimental data, which are improved when the simulations considering the solvated molecule in a combination of discrete solvent molecules interacting with the solute and the application of continuous dielectric model. Besides, the study indicates that the experimental hyperpolarizabilities seem to be a property of the solute-solvation shell system. These facts have affirmed that the theoretical approach employed can be successfully used to foresee the variation in beta due to modifications in the D/A position. Moreover, a theoretical study of the ground state absorption is performed and compared with experimental data. (C) 2008 Elsevier B.V. All rights reserved.

Elementary Petri net inside RFID distributed database (PNRD)

Usually, a Petri net is applied as an RFID model tool. This paper, otherwise, presents another approach to the Petri net concerning RFID systems. This approach, called elementary Petri net inside an RFID distributed database, or PNRD, is the first step to improve RFID and control systems integration, based on a formal data structure to identify and update the product state in real-time process execution, allowing automatic discovery of unexpected events during tag data capture. There are two main features in this approach: to use RFID tags as the object process expected database and last product state identification; and to apply Petri net analysis to automatically update the last product state registry during reader data capture. RFID reader data capture can be viewed, in Petri nets, as a direct analysis of locality for a specific transition that holds in a specific workflow. Following this direction, RFID readers storage Petri net control vector list related to each tag id is expected to be perceived. This paper presents PNRD cornerstones and a PNRD implementation example in software called DEMIS Distributed Environment in Manufacturing Information Systems.