In arid climates water is a limited resource, and turfgrass is often irrigated with municipal effluent. However, the effects of continuous turfgrass irrigation with sewage effluent on soil and leachate water quality needs to be evaluated. The objective of this field experiment was to evaluate the effect of secondary treated municipal effluent irrigation on soil and leachate properties under a turf groundcover during the first 16 mo of irrigation. Research plots were irrigated identically with either effluent or potable water using a leaching fraction of approximately 20%. Effluent irrigation resulted in significant changes in soil properties after a relatively short period of time. After 16 mo of use, when compared with potable irrigation, effluent was found to increase electrical conductivity (EC) by 0.5 dS m−1, NO3–N by 7.8 mg kg−1, P by 31.7 mg kg−1, K by 134 mg kg−, Na by 6.0 mmol L−1 and the exchangeable sodium percentage (ESP) by 6.8. Soil Ca + Mg concentrations were greater under effluent irrigation by 0.5 mmol L−1 but decreased during the study period. Soil pH was not significantly different from potable irrigation. Leachates collected at 0.61‐m depth indicated that effluent soil leachates were higher than potable leachates primarily in EC by 0.2 dS m−1 and Na content by 0.8 mmol L−1. The increase did not exceed current recommended limits for drinking water quality.
Due to limited water resources, golf course irrigation with municipal sewage effluent is a common practice, and, in some areas of the USA Desert Southwest mandatory. However, effluent irrigation changes soil properties and therefore different management practices are needed for good quality turfgrass. This field experiment evaluated the continuous use of secondary treated municipal sewage effluent on turfgrass quality over a 64‐wk period. In April 1987, common bermudagrass (Cynodon dactylon L. Pers.) was seeded to a Sonoita gravelly sandy loam (coarse‐loamy, mixed, thermic Typic Haplargid) and maintained under fairway conditions. In October of that year, perennial ryegrass (Lolium perenne L.) was overseeded to maintain an actively growing turf. Plots were irrigated identically with either effluent or potable water. Effluent irrigation led to significantly lower seed emergence but improved seed establishment. Turf quality was assessed under each irrigation with four N fertilization rates of 0, 16.1, 32.3 and 48.4 kg N ha−1 (4 wk)−1. Established effluent irrigated turf did not show signs of osmotic stress with the leaching fraction employed. Effluent provided significant amounts of nutrients at high application rates. No single fertilization rate or irrigation regime consistently produced a superior turf quality over the course of the whole study. Effluent irrigated turf showed signs of overfertilization, greater heat stress and chlorosis of overseeded ryegrass stands during the summer months on plots receiving N fertilizer amendments. Municipal effluent did produce a high quality turf, but, the greater soluble salt and nutrient content of the water necessitate special management strategies.
Ultrasonic wave based techniques are widely used for damage detection, and for quantitative and qualitative characterization of materials. In this study, ultrasonic waves are used for probing the response of additively manufactured 316L stainless steel samples as their porosity changes. The additively manufactured stainless steel specimens were fabricated using a laser powder bed fusion (LPBF) metal 3D printer. Four different levels of porosity were obtained by suitably controlling the LPBF process parameters. For generating ultrasonic waves, lead zirconate titanate (PZT) transducers were used. The signals were generated and propagated through the specimens in a transmission mode setup. Both linear and nonlinear analyses were used during the signal processing of the recorded signals for damage characterization. Linear ultrasonic parameters such as the time-of-flight (related to wave velocity) and signal amplitude (related to wave attenuation) were recorded. The nonlinear ultrasonic parameter, Sideband Peak Count - Index (SPC-I), was obtained by a newly developed nonlinear analysis technique called the SPC-I technique. Results obtained for the specimens were analyzed and compared for both linear and nonlinear ultrasonic analyses. Finally, the effectiveness of the SPC-I technique in monitoring porosity levels in additively manufactured specimens is discussed.
Guided acoustic wave based techniques have been found to be very effective for damage detection, and both quantitative and qualitative characterization of materials. In this research, guided acoustic wave techniques are used for porosity evaluation of additively manufactured materials. A metal 3D printer, Concept Laser Mlab 200 R Cusing™, is used to manufacture 316L additively manufactured (AM) stainless steel specimens. Two levels of porosity are investigated in this study, which was controlled by a suitable combination of scan speed and laser power. The sample with lower level of porosity is obtained with a low scanning speed. Lead Zirconate Titanate (PZT) transducers are used to generate guided acoustic waves. The signal is excited and propagated through the specimens in a single sided transmission mode setup. Signal processing of the recorded signals for damage analysis involves both linear and nonlinear analyses. Linear ultrasonic parameters such as the time-of-flight and magnitude of the propagating waves are recorded. The nonlinear ultrasonic parameter, the Sideband Peak Count Index (SPC-I) is obtained by a newly developed nonlinear analysis technique. Results obtained for both specimens are analyzed and compared using both linear and nonlinear ultrasonic techniques. Finally, the effectiveness of SPC-I technique in monitoring porosity levels in AM specimens is discussed.
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