Sidelobe elimination for generalized synthetic discriminant functions by a two-filter correlation and subsequent postprocessing of the intensity distributions

One of the most important problems in optical pattern recognition by correlation is the appearance of sidelobes in the correlation plane, which causes false alarms. We present a method that eliminate sidelobes of up to a given height if certain conditions are satisfied. The method can be applied to any generalized synthetic discriminant function filter and is capable of rejecting lateral peaks that are even higher than the central correlation. Satisfactory results were obtained in both computer simulations and optical implementation.     

Electrochemical and geometrical characterization of iridium oxide electrodes in stainless steel substrate

A geometrical and electrochemical characterization of stainless steel electrodes electrodeposited with iridium oxide (IrO₂) is presented. There is a dramatic increase in the double layer capacitance (C) and an important decrease in the charge transfer resistance (R_ct) after electrodeposition, causing also a significant two orders of magnitude reduction of the electrode–electrolyte interface impedance (EEIZ). These phenomena may be explained by the fine-grained iridium oxide, which has a high grain boundary density and which increases the actual electrodic area. An RC model is presented, which would explain the electrical behaviour of the system.     

Development in lipid analysis: Some new extraction techniques and in situ transesterification

The development of methods for analyzing fatty acids that provide rapid and reliable results is currently in great demand. Recently, different lipid extraction procedures such as microwave or supercritical fluid extraction have been researched. Both procedures avoid the use of large volumes of solvents and provide rapid lipid isolations. Only a few papers have reported work on microwave extraction, but many studies about supercritical fluid extraction have been carried out and have been gaining acceptance within the scientific community. Avoiding the lipid isolation step, by synthesizing fatty acid esters by simultaneous lipid extraction and derivatization through in situ reactions, has also been proposed. The saving of time and reagents is significant. Owing to the differences among the procedures, some knowledge of their characteristics is essential in order to improve methods and achieve reliable and accurate results. Clearly, results depend on factors such as the type of catalysis selected, the use of nonpolar solvents, heating applied during the synthesis, and the degree of suitability of the procedure chosen for the particular features of each sample.     

A Paradigm for Dynamic Coordination of Multiple Robots

In this paper, we present a paradigm for coordinating multiple robots in the execution of cooperative tasks. The basic idea in the paper is to assign to each robot in the team, a role that determines its actions during the cooperation. The robots dynamically assume and exchange roles in a synchronized manner in order to perform the task successfully, adapting to unexpected events in the environment. We model this mechanism using a hybrid systems framework and apply it in different cooperative tasks: cooperative manipulation and cooperative search and transportation. Simulations and real experiments demonstrating the effectiveness of the proposed paradigm are presented.     

Influence of Chemical Reactions in Magnesia-Graphite Refractories: I, Effects on Texture and High-Temperature Mechanical Properties

Four formulations of magnesia-graphite-aluminum metal (antioxidant) bricks were prepared from the same raw materials, using the standard commercial practices. Chemical analysis and determination of room-temperature modulus of rupture and Young's modulus, as well as a complete microstructural characterization of the as-received materials, were performed. For high-temperature modulus-of-rupture and Young's modulus data, test samples of the four brick compositions were heated to 1000°, 1200°, and 1450°C in flowing argon (<1000 ppm oxygen at 1000°C) and then loaded mechanically in flexure. Modulus-of-elasticity values ranged from 3.7 to 16.2 GPa and reflected strong effects of aluminum-metal concentration and treatment temperature. Young's modulus evolution with temperature was determined by the evolution of the microstructure in the bulk of the specimens. Modulus-of-rupture values ranged from 6 to 21 MPa, and their evolution with temperature was determined by the evolution of the microstructure in the bulk of the specimens at the lower testing temperatures ( T lessthan equal to 1200°C) and by phase assemblages in the surface regions of the specimens-essentially by the presence of the dense MgO zone-at 1450°C.     

Untersuchungen zur Sensibilisierung von Azofarbstoff-Perhalogenid-Systemen

Investigations Concerning Sensitization of Silver Free Information Recording Materials with Azo Dyes and Polyhalogen Compounds Recording materials mentioned in the title are sensitive to the visible region of light. The reason therefore is an energy transfer from the azo dye to the polyhalogen compounds, preferentially CBr₄. It's possible to separate the absorption spectra of azo compounds used in this work into two gaussian functions, which relates to n,π*- and π,π*-transitions. Only the excitation of the n,π*-transition causes sensitization. A mechanisms of sensitization is proposed.     

Using speciation diagrams to improve synthesis of magnetic nanosorbents for environmental applications

This work addresses environmental applications of magnetic nanoparticles. We highlight the chemical design of filtration aids based on magnetic nanoferrites coated with specific ligands potentially used in magnetic separation of pollutants from water. From electrochemical measurements, we determined the concentration of the surface sites in function of pH for the precursor magnetic nanoparticles. Then, coupling the speciation diagrams of the precursor nanoferrite particle surface with that of the specific ligand, it was possible to provide a theoretical prediction of the optimal pH for particle surface-ligand complexation, leading to advances in nanosorbents developing.     

Recursive algorithm to directly obtain the sum of correlations in a CSS

This paper presents a new recursive algorithm to directly obtain the sum of the autocorrelation functions of the M sequences belonging to a Complementary Set of Sequences (M-CSS). The proposed algorithm allows a digital filter with only one stage to be obtained, what significantly reduces the total number of memory requirements, multiplications and additions to be performed in comparison with the use of M correlators, even when these correlators could have an efficient implementation. The use of this algorithm can be of great relevancy since there is an increasing interest in the use of CSS (or derived sequences such as Loosely Synchronized—LS-sequences or Zero Correlation Zone—ZCZ-sequences) in the field of communications and sensor systems.