The Use of Wheel Brakes on Airplanes

The results of tests to determine the effect of wheel brakes on the landing run of an airplane under conditions of load and at various wind velocities are presented

The effect on annoyance estimation of noise modeling procedures

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Modeling of second-harmonic generation in periodic nanostructures by the Fourier modal method with matched coordinates

We present an advanced formulation of the Fourier modal method for analyzing the second-harmonic generation in multilayers of periodic arrays of nanostructures. In our method, we solve Maxwell’s equations in a curvilinear coordinate system, in which the interfaces are defined by surfaces of constant coordinates. Thus, we can apply the correct Fourier factorization rules as well as adaptive spatial resolution to nanostructures with complex cross sections. We extend here the factorization rules to the second-harmonic susceptibility tensor expressed in the curvilinear coordinates. The combination of adaptive curvilinear coordinates and factorization rules allows for efficient calculation of the second-harmonic intensity, as demonstrated for one- and two-dimensional periodic nanostructures

Wideband current transformers for the surveillance of the beam extraction kicker system of the Large Hadron Collider

The LHC beam dumping system must protect the LHC machine from damage by reliably and safely extracting and absorbing the circulating beams when requested. Two sets of 15 extraction kicker magnets form the main active part of this system. A separate high voltage pulse generator powers each magnet. Because of the high beam energy and the consequences which could result from significant beam loss due to a malfunctioning of the dump system the magnets and generators are continuously surveyed in order to generate a beam abort as soon as an internal fault is detected. Amongst these surveillance systems, wideband current transformers have been designed to detect any erratic start in one of the generators. Output power should be enough to directly re-trigger all the power trigger units of the remaining 14 generators. The current transformers were developed in collaboration with industry. To minimize losses, high-resistivity cobalt alloy was chosen for the cores. The annealing techniques originally developed for LEP beam current measurement in collaboration between CERN and industry allowed to extend the frequency response beyond that of traditional core materials. The paper shows the results obtained, exposes the problems encountered with shielding, conductor position sensitivity, load resistor technology and their solutions. The know-how acquired during the collaboration was further applied by the industrial partner to cover a wider range of sensitivity, size and frequency

Manipulating within-orchard and adjacent habitats to provide better pest control in organic orchards. Some elements for modulating “orchard tree-pest-natural enemy” relationships

The control of pests in organic orchards cannot solely rely on the use of direct control methods. The effect of manipulating the habitat of orchard pests and natural enemies through tree architecture and the increase of plant diversity has been investigated in an experimental organic apple orchard and in a pear orchard, in order to provide information about the potential benefits of these cultural practices. Tree training affected the development of the most detrimental pests of apple trees, and the centrifugal training system globally provided better aphid (Dysaphis plantaginea) and mite (Panonychus ulmi) control than the more classical Solaxe system, whereas codling moth (Cydia pomonella) was favoured compared to Solaxe. The study of an experimental hedgerow designed to optimise protection of the pear orchard allowed us to validate the basic principles of designing plant assemblages to increase plant diversity in the orchard surroundings, namely the introduction of a succession of resources favouring the natural enemies of the key orchard pests, and to avoid detrimental effects (pests or diseases shared with the crops). This experiment and other studies suggest that manipulating the plant diversity adjacent to the orchard has an effect on entomocenosis. However, the potential benefits for the orchard only concern the control of pests that can be tolerated at high infestation rates

EL ASCENSO SOCIAL Y LA UNIVERSIDAD

En un momento histórico, como el que estamos viviendo, donde surge una sobrevaloración extrema por los bienes de consumo, que produce la sofisticada omnipresente tecnología imperante, asoman dicotómicamente grandes diferencias sociales, que se traducen en importantes y lacerantes desigualdades entre las personas. Es así como, como a efectos de encontrar caminos alternativos, o al menos observar sendas que permitan allanar las desigualdades señaladas , nos dedicaremos a profundizar líneas de acción, que supieron pergeñar en nuestro reciente pasado, marcando en forma fehaciente la equidad desde la Universidad. En clara observancia, de dimensionar lo acontecido en el ámbito universitario, a partir de mediados del siglo pasado, cuyas pautas y preclaras fundamentos aún hoy en día se mantienen airosamente. Así resultan, como claros y contundentes exponentes la creación de la Universidad Obrera Nacional, acaecida en 1948; y la sanción del Decreto Nº 29337/49, el cual derogo el arancelamiento universitario. Acciones que le imprimieron al Sistema universitario Nacional, características que propugnaron por la equidad social, y que nos saben distinguir favorablemente de la propuesta académica, que ofrecen otros países. Es así como consideramos relevante recrear históricamente los dos hechos citados, en pos de asegurar su continuidad y validar la connotación social impulsada