Transcript Prediction of PVC pipes performance under permeation conditions

Various pathways of diffuse
reflectance
Prediction of PVC pipes performance
under permeation conditions
L. Esteve Agelet1, C. R. Hurburgh1 Jr., F. Mao2, and J. A. Gaunt2
Department of Agricultural and Biosystems Engineering1
Department of Civil, Construction and Environmental Engineering2
Iowa State University, Ames, Iowa
© 2006 Iowa State University and AwwaRF
2006 IDRC Conference
Chambersburg, PY
4-11 August , 2006
INTRODUCTION
• Permeabilization: A mass transport or flux of solvent through a nonmetallic,
porous
materialordue
an activity
gradient.
Permeabilization:
A mass
transport
fluxtothrough
a material
due to an
activity gradient. Concern for buried waterlines where the soil is contaminated
with organic compounds, due to spills or leaks
• 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)
OBJECTIVE
Develop NIR calibrations for predicting
susceptibility of PVC pipes to permeation by
organic solvents
MATERIALS AND METHODS
 Pipe Samples
- Set of 28 pipes from 5 major manufacturers
- 6 diameter sizes: ½” , ¾”,1”,1+ ¼”, 1+ ½”, and 2”
- Three 5” samples from each pipe were cut for the
study
- 6 scans/sample
 Reference data
- Slope K (mm/h1/2) from the moving front test using pure toluene as organic solvent
1.8
Moving front thickness (mm)
1.6
1.4
1.2
1
2
0.8
R = 0.9988
0.6
0.4
0.2
0
0.00
1.00
2.00
3.00
4.00
5.00
Square root of tim e (h1/2)
6.00
7.00
8.00
MATERIALS AND METHODS (Contd.)
Instruments
Foss ® NIRsystem 6500
Labspec® Pro A108310
Foss-NIRsystems, Silver Spring, MD
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
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:
r2 = 0.94 and RPD = 4.27
ASD instrument:
r2 = 0.90 and RPD = 2.72
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:
r2 = 0.92 and RPD = 2.93
ASD instrument:
r2 = 0.90 and RPD = 1.90
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.
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
QUESTIONS?