Effect of Rayleigh Wave on Ultrasonic Underground Imaging

AbstractIn order to acquire image with higher resolution and less error for detecting underground objects, a three dimensional ultrasonic underground imaging technique using an electromagnetic-induction type sound source and an amplitude correlation synthesis processing (ACSP) method has been proposed in our previous work. Depending on the conditions of the ground surface, Rayleigh waves propagating along the surface directly may be received with significant amplitude by the receiver array. That will cause interference with the reflect signal of the underground objects and will bring forth error images to the imaging result. In this paper, the Rayleigh wave with comparatively high amplitude is measured experimentally in a model field filled with mountain sands, and its waveform is estimated and simulated approximately by an exponentially decaying sinusoidal wave. The effect on the image of underground object is discussed by synthesizing the received signal with the modeled Rayleigh wave with various relative amplitudes. The result images calculated by ACSP method show that the effect of Rayleigh wave is not marked when its peak amplitude is not greater than that of the signal reflected from the underground object

Bayesian Modeling for Estimating Cattle’s Dung position in Pasture

Livestock excrement is one of the major sources of greenhouse gas (GHG) emission in pasture. As a first step in evaluating its contribution to overall GHG emissions, an understanding of excretion distribution patterns in pastures is required. Betteridge et al. (2010) describe a urine sensor that detects and logs each urination event of female sheep and cattle. The urine sensor records time and ambient temperature at one-second intervals however, patters of dung distribution are not specified. The objective of this study was to predict spatial distribution of cattle dung. The knowledge of livestock excrement position may be useful for farmers to minimize overall GHG emissions

Federal Financial Relations in Australia

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The life pattern of Australian

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Reform on the System of Taxation 1989,and it\u27s Effects on the Local Finance

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