Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

In 1484 and 1485 a printer called Castro produced several editions of laws at Huete (Cuenca). Between 1483 and 1493, and using the same types, he printed crusade indulgences that major bibliographical catalogues have assigned to Huete while various studies have given Toledo as their place of printing. Castro can be identified as the Álvaro de Castro who agreed with the Chapter of Santiago de Compostela in 1483 to print an edition of a breviary. This article examines the evidence that has led the press that printed the indulgences to be assigned to Huete or Toledo. This evidence is questioned and an argument, based on several documents and on the material analysis of the indulences themselves, put forward suggesting that they were in fact printed in the Monastery of Nuestra Señora de Prado at Valladolid. It shows that crusade indulgences were printed in that monastery in the 15th century and that Castro’s indulgences should be assigned to Valladolid.

This article is a chronological survey of the material and techniques used to print music in Spain from 1485 to 1550. It offers a new appreciation of the role played by printed fragments of music. Rather than being mere woodcut ‘illustrations’, they formed part of the typographical composition, just like the texts they were printed alongside.

Airborne acoustic insulation prediction models allow to evaluate the sound transmission loss of construction solutions in buildings. Among the different building materials used in constructions, homogeneous and isotropic materials of various thicknesses, such as concrete and glass, are commonplace. Due to the limitations of simple panels made from materials of standard thickness, in order to increase the acoustic insulation it is necessary to add various layers of the same or different materials. This research presents a model based on several approximations depending on the frequency range and comprises multi-layer panels joined together using “spot” techniques, such as by screws or nails. The model performance is evaluated with a comparison between predictions obtained using the commercial software INSUL and the model proposed by the authors. The predicted values are also compared with laboratory measurements obtained according to ISO 140-3. This research considers panels grouped into two categories of materials: light and heavyweight materials. The transmission loss in third octave bands, the weighted sound reduction indices and the spectral adaptation terms Rw (C,Ctr) are examined. Statistically, the results show that the proposed model agrees well with real measurements, both for single and multi-layer panels.

Vertical gardens, called "Greenery Systems", are a new tendency in modern constructions. They are applied increasingly more frequently on those buildings where energy and ecological considerations, environmentally friendly, are a priority. Some main features of these technologies are: thermal insulation improvement, environmental pollution filtering, acoustic absorption, water retention and a friendly aesthetic appearance. Vertical gardens can have dissimilar acoustic features because they depend on the kind of support, substrate and vegetation used. For this reason, nowadays, collected data are very diverse and incomplete and it is necessary to expand the data available to provide more alternatives with practical application. In this work, acoustic absorption of modular vertical greening was studied. Each module was developed with a rigid PVC base covered with fibrous material forming pockets, where the substrate and vegetation were placed. The plant species that were used are some of the most widespread ones in the region, in order to achieve a good adaptation and simple maintenance.

In this work, a directional loudspeaker, also known as a parametric array loudspeaker (PAL), is designed and constructed. The operation is based on the phenomenon called self-demodulation that happens when high-frequency beams interact in a viscous medium, due to its non-linear properties. The sound obtained after the self-demodulation is formed in the beam of the ultrasonic carrier signal propagating beyond the absorption distance in which the carrier has been sufficiently attenuated. This generates a focused audible signal and therefore a directional polar pattern of narrow angle. In this paper two modulation methods are evaluated: double-sideband amplitude (AM-DBL) and pulse-width modulation (PWM). Its effect on directionality, sound pressure level and harmonic distortion is experimentally analyzed.

In this work we present an optical method for the direct determination of the piezoelectric coefficient of polymeric thin films. This is achieved through the measurement of nanometric mechanical displacements generated in the film when it is excited by low frequency harmonic electrical signals (0.5 Hz). The system is based on the temporal speckle pattern interferometry technique and the recovery of phase by using a bivariate empirical mode decomposition framework. The experimental scheme was used on a sample of vinylidene polyfluoride deposited on a glass substrate. The sample presents similar conditions to those found in the characterization of complex fluids by photoacoustic techniques. The measured value agrees with those obtained by other methods and with the value reported by the manufacturer.

Auralization is a term introduced to describe the recreation of the experience of acoustic phenomena a listener would perceive in a specific soundfield. Sound propagation in a soundfield can be simulated with geometric based models or wave based models. Each one offers particular advantages and disadvantages. For wave based models, the finite element method, the boundary element method or the finite difference method are widely mentioned. They are characterized for achieving very precise results for individual frequencies applied to small and moderately sized rooms. Geometric methods lead to the ray tracing method or the image source method. These methods achieve good results for high frequencies and are efficient in large rooms and complex structures, but are not able to represent in a simple manner specific wave phenomena such as diffraction. Commercial software used to produce auralizations is usually based on a hybrid model combining ray tracing and image sources. This paper proposes an exploration on possible advantages and challenges on the use of the k-space pseudospectral method for wave based auralizations.

Acoustics is an intrinsically interdisciplinary science that has changed the way it has been taught in recent decades. Currently in higher education its teaching is varied and even opposed, applying methods such as theoretical-practical lectures to problem-based learning where the student is the main protagonist of their own learning, since the inquiry conducted by the student leads the process. At the same time, the new paradigms of higher education prioritize students'research skills. This document describes two examples of guided research, applied pedagogical innovation in the subject Fundamentals of Acoustics and Electroacoustic of the National Technological University, showing favourable results in the learning process.