Compensation of biased excitation effects for MLS-based nonlinear systems' identification

MLS-based identification of nonlinear systems is largely affected by deviations in the excitation signal amenable to the combined effect of DC-offset and an arbitrary gain. These induce orthogonality loss in the MLS filter bank output, thus invalidating the underlying identification construction. In this paper we present a correction algorithm to derive the corrected Volterra kernels from the biased estimations provided by the standard MLS-based procedure

Synthesis of sugar oxazolines by intramolecular Ritter-like reaction of D-fructose precursors

Treatment of D-fructopyranose and D-fructofuranosc 1,2-O-acetonide derivatives with triflic acid in the presence of a variety of nitriles results in the formation of fused or spiro 2-oxazolines. The reaction implies (i) activation of the anomeric centre with simultaneous isopropylidene cleavage, (ii) nucleophilic addition of the nitrile to the corresponding oxocarbenium cation intermediate and (iii) subsequent trapping of the resulting nitrilium ion species by the remaining hydroxyl group in an intramolecular Ritter-like reaction

Design and analysis of a non-hysteretic passive magnetic linear bearing for cryogenic environments

In this study, the mechanical design and analysis of a magnetic levitating linear bearing suitable for working in the nonhysteretic range of forces is presented. The semi-cylindrical design of the superconductor provides stable equilibrium positioning and restoring forces in all degrees of freedom except for two with a cylindrical magnet floating along the axis of revolution/displacement. Using finite element analysis, it has been proven that the magnet can float stably and passively in a complete non-hysteretic Meissner state. This non-hysteretic passive linear bearing could be suitable for long-stroke precision positioning. The high translational symmetry of the magnetic field seen by the superconductor assures a usable long stroke of around 90mm with full performance and 150mm with reduced performance. This linear bearing in combination with an actuating system for only one degree of freedom could be used for accurate precision positioning systems for cryogenic environments with zero hysteresis in the movement.European Community's Seventh Framework Progra

Transpose return relation method for designing low noise oscillators

In this paper, a new linear method for optimizing compact low noise oscillators for RF/MW applications will be presented. The first part of this paper makes an overview of Leeson's model. It is pointed out, and it is demonstrates that the phase noise is always the same inside the oscillator loop. It is presented a general phase noise optimization method for reference plane oscillators. The new method uses Transpose Return Relations (RRT) as true loop gain functions for obtaining the optimum values of the elements of the oscillator, whatever scheme it has. With this method, oscillator topologies that have been designed and optimized using negative resistance, negative conductance or reflection coefficient methods, until now, can be studied like a loop gain method. Subsequently, the main disadvantage of Leeson's model is overcome, and now it is not only valid for loop gain methods, but it is valid for any oscillator topology. The last section of this paper lists the steps to be performed to use this method for proper phase noise optimization during the linear design process and before the final non-linear optimization. The power of the proposed RRT method is shown with its use for optimizing a common oscillator, which is later simulated using Harmonic Balance (HB) and manufactured. Then, the comparison of the linear, HB and measurements of the phase noise are compared

Diseño y optimización de ruido de fase en osciladores utilizando la NDF.

In this paper the use of the NDF is proposed as a general method suitable for analysing any oscillator topology. The most important advantage of this method is that it provides an unique procedure to analyse any oscillator. It also makes possible the phase noise optimization in the linear design phase for any oscillator. An additional advantage of this method is that it does not require any proviso verification as all classic methods need. The use of the NDF method is illustrated with the design of two examples. These two oscillators are manufactured and the simulation results are compared with the measurements showing good agreement. These results confirm the excellent possibilities of the proposed method for low noise oscillators design

Serological Detection of Viral Infections in Captive Wild Cats from Costa Rica

Serum samples from a total of 44 wildcats, 28 margays (Leopardus wiedii), 10 ocelots (Leopardus pardalis), four jaguaroundis (Herpailurus yaguaroundi), one oncilla (Leopardus tigrina), and one jaguar (Panthera onca) were obtained between January 2001 and August 2002 from the Profelis Centre for rehabilitation of wild felids, located in the northwestern region of Costa Rica. Forty three samples were tested for antibodies against feline immunodeficiency virus (FIV) and p27 antigen of feline leukemia virus (FeLV), 42 samples for antibodies against feline parvovirus (FPV), and 30 for antibodies against feline calicivirus (FCV). None of the samples contained detectable antibodies against FIV or p27 antigen of FeLV, all samples contained antibodies against FPV, and one sample contained antibodies against FCV

Low-cost measurement for a secondary Mode S radar transmitter

A low-cost, multiple-purpose, and high-precision timing test setup for the measurements of secondary Mode S radar transmission signal was proposed. The goal was to fully guarantee compliance of the proposed transmitter under test with the really hard International Civil Aircraft Organization requirements using traditional measurement equipment, which was difficult or even impossible to ensure up to now. The low-cost structure proposed in this paper allows the user to perform measurements independently of the measurements performed by the pieces of test equipment shelled by the manufacturer of radar, which is a very important aspect since the independence of the verifications is a mandatory requirement established by the safety standards of civil aviation. The proposed setup has been used to verify several transmitters with some defects that are not detected by monopulse secondary surveillance radar specific pieces of test equipment that are focused on more high-level functionalities. It also is valid and it has been used, as a general-purpose setup, for testing other radio navigation aids

Post acquisition business synergies of a foreign affiliate. Case study of companies in Nuevo Leon (La importancia de la creación de sinergias, después de realizar una adquisición de filiales en el extranjero, casos empresas de Nuevo León)

Summary: This article will explain the importance of creating synergies after having acquired foreign affiliates. Interviews were conducted to executives of four of the most important manufacturing companies in Nuevo Leon, which have been involved in the international acquisition process of foreign affiliates. Also presented are 10 areas where synergies may be obtained after having acquired a foreign affiliate, in accordance with (Marin and Ketelhohn, 2008) economies of size at corporate headquarters, greater opportunities for professional development, corporate image, interdivisional transactions, vertical integration, economies of scale and/or scope, coordination of skills, learning center, leverage of intangible assets and unleashing of skills. Resumen: Este artículo explica la importancia de la creación de sinergias después de realizar una adquisición de filiales en el extranjero. Se realizaron entrevistas a ejecutivos de cuatro de las más importantes compañías manufactureras en Nuevo León con experiencia en un proceso de adquisición de filiales extranjeras. Asimismo, considerando el trabajo de Marin Ketelhohn (2008) se estudian 10 áreas en las cuales se hayan obtenido sinergias después de haber adquirido una filial extranjera, esto es, economías de escala a nivel dirección del coorporativo, mayores oportunidades para el desarrollo profesional, imagen corporativa, transacciones interdivisionales, integración vertical, economías de escala y/o alcance, coordinación de habilidades, centros de aprendizaje, apalancamiento de activos intangibles