For the effective evaluation of hydraulic conditions of pipeline system, it is necessary to evaluate not only the material properties but also unsteady flow conditions, such as pressure wave. In this study, quantitative evaluation of pressure wave is going to be performed, applying acoustic emission (AE) and digital image correlation methods in pipeline. The pressure waves were detected in pipeline, based on control of valve closing time (0.40-10.48s). Thus, the maximum pressure could be detected by comparing maximum pressure level with a rate of AE generation, which is analyzed by AE parameters. Using digital image correlation method, a relationship between maximum pressure level and displacement is correlated. By monitoring the pressure waves in service pipeline based on these results, the generated pressure waves in pumping flow conditions is successfully detected by AE.
TDR (Time-domain reflectometry) is an advanced method for monitoring the water content in fields. TDR measurements can provide accurate information about vegetation effects on both spatial and temporal soil water distribution. The objective of this study was to examine the effects of vegetation conditions on the distribution of the soil water content. Soil water content was measured to express the spatial distribution in the surface layer (0-0.2 m) in grass, corn, and non-planted fields. Additionally, using the TDR method with multiple probes with different lengths, the measurements were conducted on a temporal basis at 4 depths (0-0.1, 0.1-0.2, 0.2-0.3 and 0.3-0.5 m) to determine the soil-water content profiles in the 3 fields. A significantly higher water content in both the grass and cornfields was found, compared to the non-planted field. Moreover, in the cornfield, we observed that microtopographic features significantly affected the spatial water distribution. The lower the soil water content, the higher the coefficient of variation of the soil moisture content. These results indicated that the effects of the vegetation conditions on the soil water distribution in the fields were significant. From the observation of the temporal soil water profiles in the 3 fields, it was found that soil management, i.e. tillage or no-tillage, was a major factor affecting the profiles.Discipline: Agricultural engineering Additional key words: electromagnetic wave, Andisol, multiple probes with different lengths JARQ 37 (4), 243 -248 (2003)
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