Visualization of acoustic intensity vector fields using scanning measurement techniques

Sound propagation paths are not always well understood mainly because of the complex nature of the source or the environment. A direct method to capture the sound energy flow throughout a room is to measure the three-dimensional sound intensity distribution across space. In the past years, several studies have been carried out using step by step measurements with a three-dimensional intensity probe consisting of a sound pressure transducer and three orthogonal particle velocity sensors. The probe’s ability to measure even in highly reverberant environments and its small size are key features required for numerous applications. However, punctual measurements are time-consuming, especially when a large number of measurement positions are evaluated. The use of advanced scanning measurement techniques, such Scan & Paint, allows for the gathering of data across a time stationary sound field in a fast and efficient way, using a single sensor and webcam only. The acoustic signals are acquired manually by moving a probe across a measurement plane whilst filming the event with a camera. In the post-processing stage, the sensor position is extracted and then used for linking a segment of the signal acquired to a certain position of the space. In this manner, the overall measurement time is reduced from hours to minutes. In this paper, the acoustic intensity vector fields of several complex examples are investigated; revealing the acoustic energy flow of several vehicles, a loudspeaker in a room, and also the interaction between an absorbing sample and a reverberant sound field

The Relation Between Process Management and Innovation – A comparison of the IT and Manufacturing Industries

This study investigates whether there are major differences between process management and innovation between the IT and more traditional industries. Although both industries are quite similar, the research results show that the IT industry is more innovative in comparison to more traditional industries. The traditional industries are more risk averse towards new technologies, which makes them less innovative than the IT industry

In-plane structure of the electric double layer in the primitive model using classical density functional theory

The electric double layer (EDL) has a pivotal role in screening charges on surfaces as in supercapacitor electrodes or colloidal and polymer solutions. Its structure is determined by correlations between the finite-sized ionic charge carriers of the underlying electrolyte and, this way, these correlations affect the properties of the EDL and of applications utilizing EDLs. We study the structure of EDLs within classical density functional theory (DFT) in order to uncover whether a structural transition in the first layer of the EDL that is driven by changes in the surface potential depends on specific particle interactions or has a general footing. This transition has been found in full-atom simulations. Thus far, investigating the in-plane structure of the EDL for the primitive model (PM) using DFT proved a challenge. We show here that the use of an appropriate functional predicts the in-plane structure of EDLs in excellent agreement with molecular dynamics (MD) simulations. This provides the playground to investigate how the structure factor within a layer parallel to a charged surface changes as function of both the applied surface potential and its separation from the surface. We discuss pitfalls in properly defining an in-plane structure factor and fully map out the structure of the EDL within the PM for a wide range of electrostatic electrode potentials. However, we do not find any signature of a structural crossover and conclude that the previously reported effect is not fundamental but rather occurs due to the specific force field of ions used in the simulations