Revista elektron

6-9

Authors: Leandro Sebastián Rodiño

The acoustic analysis of gunshots provides valuable information in the forensic field. Through the measurement and calculation of the physical properties produced by the deflagration of the gases at the moment of shooting, it is possible to estimate the released acoustic energy. First, the calculation of the angular source energy proposed in the ISO 17201 standard is applied. Subsequently, the estimation of the acoustic propagation in free field is carried out to obtain the sound exposure level. Finally, a field test is performed in order to validate the simulated values. The implementation of the method is compiled in a practical software to automate a quick data loading and obtaining results.

16-23

Authors: Joaquín Mansilla Benasco, Laurence Bender, Leonardo Pepino

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.

29-38

Authors: Leonardo Garberoglio, Claudio Pose, Ignacio Mas, Juan Ignacio Giribet

In this work, the design of an autopilot for small unmanned vehicles is presented. It is focused mainly on the system’s architecture, while presenting some important remarks of the developed firmware. In particular, the firmware uses rosserial, a package that allows a simple connection with ROS (Robot Operating System), which is useful for a number of applications. The work is validated experimentally on an multirotor-type unmanned aerial vehicle (UAV), and on an autonomous surface vehicle (ASV). These vehicles have been developed by our group, and this work provides information about such projects, which may be useful for those interested in the development of this kind of vehicles.

46-51

Authors: Jorge Petrosino, Lucas Landini, Georgina Alejandra Lizaso, Antonio Ian Kuri, Ianina Canalis

Using k-wave toolbox as teaching aid in subjects related to physical acoustics is proposed. This toolbox enables simple and efficient simulation of time domain wave propagation. It is widely used for simulating the behaviour of ultrasonic waves in biological media. By adding a small number of instructions it is possible to simulate acoustic field propagation for two-dimensional conditions, based on a reference image (BMP file) in which points of different colours represent specific elements within the simulation. This enables experimentation of different situation using the k-wave toolbox with minimal MATLAB/Octave know-how. Any alteration on the images by simple cut, paste, move or rotate operation results in new simulation conditions.