Prediction of PVC pipes performance under permeation conditions
L. Esteve Agelet 1, C. R. Hurburgh 1 Jr., F. Mao 2, and J. A. Gaunt
2 Department of Agricultural and Biosystems Engineering 1
Department of Civil, Construction and Environmental Engineering 2
Iowa State University, Ames, Iowa 2006 IDRC Conference
Chambersburg, PY 4-11 August, 2006 2006 Iowa State University and
AwwaRF Various pathways of diffuse reflectance
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INTRODUCTION Permeabilization: A mass transport or flux through
a material due to an activity gradient. Concern for buried
waterlines where the soil is contaminated with organic compounds,
due to spills or leaks INTRODUCTION Permeabilization: A mass
transport or flux of solvent through a non- metallic, porous
material due to an activity gradient. Concern for buried waterlines
where the soil is contaminated with organic compounds, due to
spills or leaks Permeation has been a proven cause of drinking
water contamination in United States and 6 other countries in
recent years (Holsen et al., 1991)
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OBJECTIVE Develop NIR calibrations for predicting
susceptibility of PVC pipes to permeation by organic solvents
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MATERIALS AND METHODS Pipe Samples - Set of 28 pipes from 5
major manufacturers - 6 diameter sizes: , ,1,1+ , 1+ , and 2 -
Three 5 samples from each pipe were cut for the study - 6
scans/sample Reference data - Slope K (mm/h 1/2 ) from the moving
front test using pure toluene as organic solvent
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MATERIALS AND METHODS (Contd.) Instruments Foss NIRsystem 6500
Foss-NIRsystems, Silver Spring, MD Labspec Pro A108310 Analytical
Spectral Devices, Inc., Boulder, CO Software - The Unscrambler
v.9.5 (Camo AS, Trondheim, Norway) Calibration method - Raw, First
and Second Svitsky-Golay Derivatives - Partial Least Squares (PLS)
with cross validation
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RESULTS The moving front test is an adequate method to get
reference data (SEL=0.001 mm) The best PLS calibration models with
raw spectral data for pipe sizes from 0.5 to 1.25 gave : Foss
instrument: r 2 = 0.94 and RPD = 4.27 ASD instrument: r 2 = 0.90
and RPD = 2.72
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RESULTS (Contd.) The larger pipes were cut for Foss instrument,
scanned and added in the calibration later, developing a second
model. The best PLS calibration models with raw spectral data for
pipe sizes from 0.5 to 2 gave : Foss instrument: r 2 = 0.92 and RPD
= 2.93 ASD instrument: r 2 = 0.90 and RPD = 1.90
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CONCLUSIONS PVC pipe permeation performance can be predicted
using spectral data from the NIR region. Larger pipes models did
not give as accurate results as models including pipes of sizes
from 0.5 to 1.25. Models from Foss 6500 instrument were more
accurate. Treatment of spectral data with derivatives gave poorer
results.
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ACKNOWLEDGEMENTS Iowa State University gratefully acknowledges
that the Awwa Research Foundation is the joint owner of the
technical information upon which this manuscript is based. Iowa
State University thanks the Foundation for its financial,
technical, and administrative assistance in funding and managing
the project through which this information was discovered. The
comments and views detailed herein may not necessarily reflect the
views of the Awwa Research Foundation, its officers, directors,
affiliates, or agents. The findings described here are preliminary
in nature and are subject to revision. A final project report will
be published by AwwaRF. 2006 Iowa State University and AwwaRF