ACTIVE CONTROL OF ENVIRONMENTAL NOISE, V: THE EFFECT OF ENVIRONMENTAL CHANGE ON THE STABILITY OF FREE FIELD SOUND CANCELLING SYSTEMS

2001 ◽  
Vol 244 (1) ◽  
pp. 107-122 ◽  
Author(s):  
S.E. WRIGHT ◽  
H. ATMOKO
Keyword(s):  
Environmental Change ◽  
Active Control ◽  
Free Field ◽  
Environmental Noise ◽  
The Stability ◽  
Field Sound

Active control of free‐field sound using near‐field energy‐based error signals

2006 ◽  
Vol 120 (5) ◽  
pp. 3198-3198
Author(s):  
Ryan T. Chester ◽  
Timothy W. Leishman
Keyword(s):  
Active Control ◽  
Near Field ◽  
Free Field ◽  
Field Energy ◽  
Field Sound

Free-field sound radiation measurement with multiple synchronous cameras

Measurement ◽  
2021 ◽  
pp. 110605
Author(s):  
Paolo Gardonio ◽  
Roberto Rinaldo ◽  
Loris Dal Bo ◽  
Roberto Del Sal ◽  
Emanuele Turco ◽  
...  
Keyword(s):  
Free Field ◽  
Sound Radiation ◽  
Radiation Measurement ◽  
Field Sound

scholarly journals <i>Couplerlib</i>: a metadata-driven library for the integration of multiple models of higher and lower trophic level marine systems with inexact functional group matching

2016 ◽  
Vol 9 (3) ◽  
pp. 947-964 ◽  
Author(s):  
Jonathan Beecham ◽  
Jorn Bruggeman ◽  
John Aldridge ◽  
Steven Mackinson
Keyword(s):  
Environmental Change ◽  
Food Web ◽  
Trophic Level ◽  
Functional Group ◽  
Coupled Model ◽  
Ecosystem Model ◽  
Biogeochemical Model ◽  
Marine Systems ◽  
The Stability

Abstract. End-to-end modelling is a rapidly developing strategy for modelling in marine systems science and management. However, problems remain in the area of data matching and sub-model compatibility. A mechanism and novel interfacing system (Couplerlib) is presented whereby a physical–biogeochemical model (General Ocean Turbulence Model–European Regional Seas Ecosystem Model, GOTM–ERSEM) that predicts dynamics of the lower trophic level (LTL) organisms in marine ecosystems is coupled to a dynamic ecosystem model (Ecosim), which predicts food-web interactions among higher trophic level (HTL) organisms. Coupling is achieved by means of a bespoke interface, which handles the system incompatibilities between the models and a more generic Couplerlib library, which uses metadata descriptions in extensible mark-up language (XML) to marshal data between groups, paying attention to functional group mappings and compatibility of units between models. In addition, within Couplerlib, models can be coupled across networks by means of socket mechanisms. As a demonstration of this approach, a food-web model (Ecopath with Ecosim, EwE) and a physical–biogeochemical model (GOTM–ERSEM) representing the North Sea ecosystem were joined with Couplerlib. The output from GOTM–ERSEM varies between years, depending on oceanographic and meteorological conditions. Although inter-annual variability was clearly present, there was always the tendency for an annual cycle consisting of a peak of diatoms in spring, followed by (less nutritious) flagellates and dinoflagellates through the summer, resulting in an early summer peak in the mesozooplankton biomass. Pelagic productivity, predicted by the LTL model, was highly seasonal with little winter food for the higher trophic levels. The Ecosim model was originally based on the assumption of constant annual inputs of energy and, consequently, when coupled, pelagic species suffered population losses over the winter months. By contrast, benthic populations were more stable (although the benthic linkage modelled was purely at the detritus level, so this stability reflects the stability of the Ecosim model). The coupled model was used to examine long-term effects of environmental change, and showed the system to be nutrient limited and relatively unaffected by forecast climate change, especially in the benthos. The stability of an Ecosim formulation for large higher tropic level food webs is discussed and it is concluded that this kind of coupled model formulation is better for examining the effects of long-term environmental change than short-term perturbations.

scholarly journals Performance Analysis of Cost-Effective Miniature Microphone Sound Intensity 2D Probe

Sensors ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 271
Author(s):  
Witold Mickiewicz ◽  
Michał Raczyński ◽  
Arkadiusz Parus
Keyword(s):  
Free Field ◽  
Sound Intensity ◽  
Cost Effective ◽  
Acoustic Power ◽  
Metrological Analysis ◽  
Architectural Acoustics ◽  
Advantages And Disadvantages ◽  
Directional Characteristics ◽  
The Stability ◽  
Prototype Measurement

This article presents the functional properties of modified versions of the 2D pressure–pressure intensity probe allowing us to determine the vector of sound intensity on a plane using a mechatronic system with one or two miniature electret microphones. The introduction contains basic information about the application areas of the sound intensity and its measurement problems. Next, the principle of operation of the probes and the construction of the prototype measurement system are described. It was subjected to comparative analysis for the stability of obtained results and accuracy of directional characteristics in free field conditions. For this purpose, experiments were conducted to analyze the flow of acoustic power in an anechoic chamber using both (one- and two-microphone) probes. The results were used for a comparative metrological analysis of the described methods and to indicate the advantages and disadvantages of both constructions. The next part of the article presents an experiment concerning the measurement of the sound intensity impulse response of a room, which is an example of practical use of the probe to analyze reflections in the room, which can be used in sound engineering and architectural acoustics.

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