Estimation of exponential decay parameters of nonstationary poisson flows of pulses

1994 ◽  
Vol 37 (2) ◽  
pp. 214-219
Author(s):  
O. P. Bukhalo
2007 ◽  
Vol 55 (4) ◽  
pp. 227-234
Author(s):  
D.B. Newton ◽  
G.A. Jenkins ◽  
B. Yu

Observed reductions in pollutant concentrations through stormwater treatment devices commonly display the characteristic form of exponential decay, in which the rate of decrease of pollutant concentration with distance is proportional to the concentration. The observation of an apparently irreducible or background pollutant concentration, C*, in many devices has led to development of the two-parameter “k-C*” model. It is known that this model is too simplistic because the parameters k and C* are not constant but can vary greatly with pollutant concentration and hydraulic conditions. This paper presents an alternative exponential decay model for filtration of particulate pollutants, which is based on simple mathematical descriptions of key removal processes. The model delivers a process-based method for estimating the exponential decay constant. Moreover, the need to specify a background concentration is eliminated. To test the theory, the model is applied to the removal of clay and silica particles from horizontal flow through an experimental gravel trench. Particle concentrations were measured at nine locations along a 7.2 m long flume. The model agrees very well with the observed change in suspended solids concentration for the two pollutant materials and the range of flow rates tested. A single model parameter, notionally representing the “stickiness” of pollutant particles, is required for different pollutant materials.


1993 ◽  
Vol 65 (9) ◽  
pp. 1240-1246 ◽  
Author(s):  
Joel. Tellinghuisen ◽  
Charles W. Wilkerson

1981 ◽  
Vol 85 (20) ◽  
pp. 2941-2946 ◽  
Author(s):  
Peter Hall ◽  
Ben Selinger

Acoustics ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 78-96
Author(s):  
Javier Alayón ◽  
Sara Girón ◽  
José A. Romero-Odero ◽  
Francisco J. Nieves

In Hispania (present-day Spain and Portugal), there are 25 structures documented of classical Roman open-air theatres, of which 10 are in the south, in the Roman Baetica (Andalusia). The Baetica embraced the progress of urbanisation in the time of the Roman emperor Augustus, where theatres, built in stone, were the foci of entertainment, performance, and propaganda of the empire. The Roman theatre in Malaga presents the archaeological remains of the main vestige of the Roman Malaca. It is located in the historical centre of the city, at the foot of the hill of the Muslim Alcazaba and was discovered in 1952. It is a medium-sized theatre whose design corresponds to a mixed construction that combines making use of the hillside for the terraces, in the manner of Greek theatres, with a major construction where rock is non-existent, thereby creating the necessary space for the stands. In this paper, the production process, adjustment, and validation of the 3D model of the theatre are analysed for the creation of a numerical predictive model of its sound field. Acoustic properties of the venue are examined and the effect of the Muslim Alcazaba and the hillside on the various acoustic descriptors is analysed. The results highlight the influence of this large stone surface mainly on the time decay parameters.


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