vii
TABLE OF CONTENTS
CHAPTER
1
2
TITLE
PAGE
DECLARATION
ii
DEDICATION
iii
ACKNOWLEDGEMENT
iv
ABSTRACT
v
ABSTRAK
vi
TABLE OF CONTENTS
vii
LIST OF TABLES
xiv
LIST OF FIGURES
xvii
LIST OF ABBREVIATIONS
xxii
LIST OF SYMBOLS
xxvi
LIST OF APPENDICES
xxvii
INTRODUCTION
1
1.1
Introduction
1
1.2
Problem Statement
2
1.3
Research Aim
3
1.4
Research Objectives
4
1.5
Research Scopes
4
1.6
Importance of Research
5
1.7
Contribution of the Research
5
LITERATURE REVIEWS
7
2.1 Introduction
7
2.2 Transmission Gas Pipeline in Malaysia
8
2.2.1
External Corrosion of Transmission Gas
viii
Pipeline
2.3
2.4
2.5
2.6
Corrosion in Soil
11
2.3.1
13
Soil-Corrosion Mechanism
Influence of Soil Physical Properties on Corrosion
15
2.4.1
Soil Texture
17
2.4.2
Degree of Aeration and Oxygen Diffusion
in Soil
21
2.4.3
Soil Consistency
22
2.4.4
Soil Moisture Content
23
Influence of Soil Chemical Contents on Corrosion
24
2.5.1
Soil Relative Acidity (pH)
25
2.5.2
Soluble Ion Content
26
2.5.3
Soil Resistivity
29
2.5.4
Oxidation-Reduction Potential (ORP)
30
Corrosion Testing
31
2.6.1
Laboratory Corrosion Measurement
32
2.6.2
Field Corrosion Measurement
33
2.7
Modelling Studies
34
2.8
The Use of Power Law Model in Corrosion
37
2.8.1
Romanoff’s Model [1957]
40
2.8.2
Rossum’s Model [1969]
40
2.8.3
Mughabghab and Sullivan’s Model [1989]
41
2.8.4
Katano’s Model [2003]
42
2.8.5
Li’s Model [2004]
43
2.8.6
Velazquez’s Model [2009]
44
2.8.7
Caleyo’s Model [2009]
45
2.8.9
Anyanwu et al. [2014]
46
2.9
3
8
Summary of Research Gap
46
RESEARCH METHODOLOGY
48
3.1
Introduction
48
3.2
Overview of AFAT and OFAT Approaches
49
3.3
Pipe Samples Collection and Coupons Preparation
54
ix
3.4
3.3.1 Cutting Process
55
3.3.2 Grinding and Cleaning Process
56
3.3.3 Weighing and Labelling Process
57
Methodology of Component 1 (Field Works)
58
3.4.1 Research Area Selection
59
3.4.2 Coupon Installation
62
3.4.3 Coupon Retrieval, On-Site Measurement
and Soil Sampling
3.5
66
Methodology of Component 2 (Simplified Site)
69
3.5.1 Simplified Sites Setup (Component 2)
69
3.5.2 Coupon Retrieval, On-Site Measurement
and Soil Sampling
3.6
3.7
72
Methodology of Component 3 (Laboratory Test)
74
3.6.1 Laboratory Experimental Setup
75
3.6.2 Preparation of Soil Medium
76
3.6.3 Soil Medium for Chemical Content
78
3.6.4 Soil Medium for Clay Content
79
3.6.5 Soil Medium for Plasticity Index
80
3.6.6 Soil Medium for Moisture Content
80
3.6.7 Soil Medium for Particle Size
81
3.6.8 Soil Medium for Control Sample
82
Steel Coupons and Soil Parameters Assessment
83
3.7.1 Coupon Cleaning After Retrieval
83
3.7.2 Assessment of Corrosion Rate According
to ASTM
87
3.7.3 Coupons Composition Analysis Using
Glow Discharge Spectrometer
3.8
Field Works Soil Measurement
88
88
3.8.1 3.8.1 Soil Resistivity Site Measurement
(ASTM International, 2012)
3.9
89
3.8.2 Soil pH Site Measurement
90
Soil Laboratory Testing
90
3.9.1 Soil Acidity Test
91
x
3.10
4
3.9.2 Soil Chloride Test
91
3.9.3 Soil Sulphate Test
93
3.9.4 Soil Sulphide Test
93
3.9.5 Soil Organic Test
93
3.9.6 Moisture Content (WC) Test
94
3.9.7 Plasticity Index (PI) Test
94
3.9.8 Particle Size (PS) Test
95
3.9.9 Clay Content (CC) Test
96
Data Analysis
97
3.10.1
Exploratory Data Analysis (EDA)
99
3.10.2
Transformation of Variables
100
3.10.3
Normality Test
100
3.10.4
Detection of Outliers
101
3.10.5
Single Linear Regression (SLR)
101
3.10.6
Correlation Matrix
102
3.10.7
Principal Component Analysis (PCA)
102
3.10.8
Multiple Regression Analysis (MRA)
102
3.10.9
Data Analysis Using Parametric Test
103
3.11
Development of External Corrosion Model
103
3.12
Concluding Remarks
104
ANALYSIS OF COMPONENT 1
105
4.1
Introduction
105
4.2
Field Work Description
106
4.3
Part 1: Preliminary Data Analysis
108
4.3.1
Stage 1: Data Classification According to
Depth
110
4.3.2
Stage 2: Non-Parametric Test
111
4.3.3
Stage 3: Data classification According to
Central Tendency
4.3.4
Stage 4: Identification of Central
Tendency
4.4
112
Preliminary Studies of Corrosion Growth Pattern
114
117
xi
5
6
4.5
Preliminary Studies of Metal Mass Loss
120
4.6
Part 2: Empirical Model Development
122
4.6.1
Exploratory Data Analysis (EDA)
124
4.6.2
Transformation and Outliers of Variables
126
4.7
Single Linear Regression Model of Each Variable
131
4.8
Correlation Matrix
141
4.9
Principal Component Analysis (PCA)
143
4.10
Mass Loss Model Development
146
4.10.1
148
Multiple Regression Analysis (MRA)
4.11
Corrosion Loss Rate Model Development
153
4.12
Concluding Remarks
154
ANALYSIS OF COMPONENT 2
156
5.1
Introduction
156
5.2
Site Classification
157
5.3
Metal Mass Loss and Soil Data Collection
158
5.4
Preliminary Studies of Corrosion Growth Pattern
161
5.5
Preliminary Studies of Metal Mass Loss
166
5.6
Empirical Model Development
168
5.6.1
Exploratory Data Analysis (EDA)
170
5.6.2
Transformation and Outliers of Variable
172
5.7
Single Linear Regression Model of Each Variable
176
5.8
Correlation Matrix
184
5.9
Principal Component Analysis (PCA)
186
5.10
Metal Mass Loss Model Development
188
5.10.1
190
Multiple Regression Analysis (MRA)
5.11
Corrosion Loss Rate Model Development
193
5.12
Concluding Remarks
194
ANALYSIS OF COMPONENT 3
196
6.1
Introduction
196
6.2
Testing Procedure
197
6.3
Collection of Metal Mass Loss and Corrosion Rate
xii
6.4
Data
198
Metal Mass Loss and Corrosion Data Analysis
202
6.4.1
Corrosion Growth Pattern For Each Soil
Variables
6.4.2
203
Determination of k and v using Two-Way
ANOVA
6.5
7
207
6.4.2.1
pH Variable
207
6.4.2.2
Chloride Content Variable
210
6.4.2.3
Sulphate Content Variable
212
6.4.2.4
Organic Content Variable
214
6.4.2.5
Moisture Content Variable
215
6.4.2.6
Clay Content Variable
217
6.4.2.7
Plasticity Index Variable
218
6.4.2.8
Particle Size Variable
220
Concluding Remarks
DISCUSSION
224
7.1
Introduction
224
7.2
Measures of Central Tendency
225
7.3
Defining the Corrosion Growth Pattern and Metal
7.4
Mass Loss
226
7.3.1
Corrosion Growth Pattern
226
7.3.2
Metal Mass Loss
229
Relationship between Metal Mass Loss and Soil
Properties and Chemical Content
230
7.5
Classification of Soil Variables towards k and v
234
7.6
Verification of the selected variable in k and v
using OFAT approach
7.7
238
Modelling Development Based on Differential
Equation of Power Law
8
222
239
CONCLUSIONS AND RECOMMENDATIONS
242
8.1
242
Introduction
xiii
8.2
Conclusions
243
8.3
Recommendations for Future Work
246
REFERENCES
248
APPENDICES A-C
261-298
xiv
LIST OF TABLES
NO.
TITLE
PAGE
2.1
Acidity and alkalinity of the soil [Doyle et al., 2003]
26
2.2
Soil corrosiveness as a function of pH [Romanoff, 1957]
26
2.3
Soil corrosiveness as a function of sulphate concentration
[ACI, 2011]
2.4
Soil corrosiveness as a function of chloride concentration
[ACI, 2011]
2.5
29
Classification of soil corrosiveness based on resistivity
[Palmer, 1990]
2.6
29
30
Soil corrosiveness index based on oxidation-reduction potential
[Starkey and Wight, 1945]
31
2.7
Existing corrosion models
36
2.8
Summary of corrosion loss-time model phase [Melchers 2003a]
40
2.9
Summary of Rossum’s model
41
2.10
Summary of Mughabghab and Sullivan’s model
42
2.11
Summary of Katano’s model
43
2.12
Summary of Li’s model
44
2.13
Summary of Velazquez’s model
45
3.1
Coupon sizes of each component
54
3.2
Site selection criteria
59
3.3
List of soil type and its origin
72
3.4
Chemical electrolyte or additive added to alter the soil medium
77
3.5
Percentage of particle size for laboratory test
81
3.6
Soil parameters testing based on available standard
83
3.7
Elemental composition of steel coupon grade API 5L X70 in
percentage
88
xv
3.8
Elemental composition of steel coupon grade API 5L X42 in
percentage
88
3.9
Example calculation of particle size
96
4.1
Sites characteristic and their specific location
106
4.2
Soil chemical content of actual field work
110
4.3
Soil physical properties of actual field work
111
4.4
Statistic summary of T-test
112
4.5
Output of T-test for two paired samples / two-tailed test
112
4.6
ML and CR data according to mean, median and maximum
113
4.7
Descriptive statistics for each variable
124
4.8
Summary of EDA
126
4.9
Log transformation of soil chemical content with ML
128
4.10
Data transformation summary
129
4.11
ML and soil chemical content data
130
4.12
ML and soil physical properties data
131
4.13
SLR summary
139
4.14
Pearson correlation coefficient matrix
142
4.15
Pearson correlation coefficient matrix (cont’d)
142
4.16
Classification of soil variables with k and v coefficient using PCA
146
4.17
Expected combination of k and v
147
4.18
R2 of all possible combinations of k and v
149
4.19
Analysis of variance of the model
151
4.20
Predicted mass loss for each site using Model C
152
5.1
Soil characteristic and their origin
158
5.2
Soil chemical content and mass loss data for simplified site
159
5.3
Soil chemical content and mass loss data for simplified site
(cont’d)
160
5.4
Soil physical properties and mass loss data for simplified site
161
5.5
Summary of v value based on theory
162
5.6
Descriptive statistics for each variable
170
5.7
EDA summary
171
5.8
Summary of data transformation
173
5.9
Log transformation data on chloride, sulphate variables
174
xvi
5.10
Log transformation data on resistivity, organic and particle size
variables
175
5.11
Summary of SLR for Component 2 analysis
178
5.12
Pearson correlation coefficient matrix
185
5.13
Pearson correlation coefficient matrix (cont’d)
185
5.14
Classification of soil variables with k and v coefficient using PCA
188
5.15
Possible combination of k and v
189
5.16
Coefficient regression of Component 2 model
191
5.17
Analysis of variance of the model
193
6.1
Summary of soil parameters for laboratory test
198
6.2
Summary of metal mass loss (gram) for soil chemical content
199
6.3
Summary of metal mass loss (gram) for soil physical properties
200
6.4
Summary of corrosion rates (mm/year) for soil chemical content
201
6.5
Summary of corrosion rates (mm/year) for soil physical properties
202
6.6
Summary of OFAT analysis for soil chemical variable
205
6.7
Summary of OFAT analysis for soil physical variable
206
6.8
ANOVA test results for soil pH variable
210
6.9
ANOVA test results for chloride content variable
212
6.10
ANOVA test results for sulphate content variable
214
6.11
ANOVA test results for organic content variable
215
6.12
ANOVA test results for moisture content variable
217
6.13
ANOVA test results for clay content variable
218
6.14
ANOVA test results for plasticity index variable
220
6.15
ANOVA test results for particle size variable
221
6.16
Summary of ANOVA and soil variables graph
222
7.1
Growth pattern by exponential value, v
228
7.2
Summary of exponential value at each research area
228
7.3
The significance of each soil variable in predicting mass loss
234
7.4
Soil variables selected towards k and v
236
7.5
Comparison of different soil-corrosion models
237
7.6
Soil variables selected towards k and v using OFAT approach
239
xvii
LIST OF FIGURES
NO.
TITLE
PAGE
2.1
Peninsular Gas Utilisation (PGU) network
8
2.2
Attributed failures mechanism for pipeline
10
2.3
Exposure of buried pipeline to the soil environment
13
2.4
The basic corrosion cell consists of an anode, a cathode, an
electrolyte, and an electrical circuit for electron flow
2.5
13
A buried pipe is anodic in wet soil with lower oxygen content and
cathodic in better oxygenated soil [Veleva, 2005]
15
2.6
Field assessment using a hand texture chart [Rowell, 2014]
18
2.7
Soil texture triangle [Hillel, 2003]
19
2.8
Atterberg limits
22
2.9
Effect of moisture on soil resistivity [Romanoff, 1957]
24
2.10
Relationship of variables affecting the rate of corrosion in soil
[Roberge, 2000]
2.11
Resistivity as a function of concentration for CaSO4 and NaCl
solutions at room temperature [Beavers and Durr, 1998]
2.12
25
28
Apparatus for conducting laboratory corrosion tests in soil [ASTM
International, 2004b]
33
2.13
Corrosion growth pattern in a function of time [Noor, 2009]
38
2.14
Multiphase phenomenological corrosion-time model [Melchers
2003a]
39
3.1
Flow chart of research methodology
49
3.2
Feasibility studies of Component 1
51
3.3
Feasibility studies of Component 2
52
3.4
Feasibility studies of Component 3
53
3.5
Pipe samples collection
54
xviii
3.6
Preparation of test coupons
56
3.7
Coupon grinding and cleaning process
57
3.8
Weighing and labelling of test coupon
58
3.9
Site A, located at 04o30'15.2"N, 103o25'13.7"E vicinity
60
3.10
Site B, located at 04o18'02.9"N, 103o24'22.3"E vicinity
60
o
o
3.11
Site C, located at 04 02' 55.5"N, 103 23'21.3"E vicinity
61
3.12
Site D, located at 03o52'19.3"N, 103o18'3.4"E vicinity
61
3.13
Site E, located at 02o36'39.55"N, 102o50'0.96"E vicinity
62
3.14
Position of steel coupons at 0.5m and 1.0m in each dug hole
63
3.15
Distance of two metre were marked before drilling job started
63
3.16
Holes were drilled using power hand auger machine
64
3.17
Steel coupons were buried at 1.0m and 0.5m depth
64
3.18
The depth of each steel coupons were checked using measured
stick
3.19
65
Each drilled holes were marked for future reference during coupons
retrieval process
65
3.20
Coupon retrieval manually using shovel
66
3.21
Coupon was retrieved at 0.5 metre depth
67
3.22
Measurement of salinity, conductivity and temperature of water
table using multimeter
67
3.23
Measurement of soil moisture content
68
3.24
Measurement of soil resistivity using Wenner 4-pin method
68
3.25
Soil preparation for Component 2 and laboratory testing
69
3.26
Polybag used in Component 2 with steel coupons in it
71
3.27
Polybags full with soil were ready to transport back to UTM
71
3.28
Completed site work
72
3.29
Preparation of steel coupons retrieval
73
3.30
Retrieved steel coupons for laboratory analysis
73
3.31
Preparation of soil samples for laboratory analysis
74
3.32
Laboratory corrosion test in soil
76
3.33
Completion of steel coupon buried in saturated soil medium
77
3.34
Kaolin mixed with washed sand to design soil samples with clay
content of 25%
79
xix
3.35
Washed sand with different particle size distributions
82
3.36
Mechanical cleaning with light brushing
85
3.37
Preparation of admixture of acid hydrochloric, hexamethlyene
tetramine and distilled water for chemical cleaning
85
3.38
Chemical cleaning process for 10 minutes immersion
86
3.39
Test steel coupon; (a) steel coupons after retrieval, (b) after
mechanical cleaning, (c) after chemical cleaning
3.40
86
Mass loss of corroded specimen resulting from repetitive cleaning
cycles [ASTM International, 2004a]
87
3.41
The Wenner four-electrode method in soil resistivity measurement
90
3.42
Framework of data analysis
99
4.1
Preliminary analysis (Part 1)
109
4.2
Metal mass loss (ML) data plotted with mean, median and
maximum data
116
4.3
Metal mass loss of Site A for one and half year of exposure
118
4.4
Metal mass loss of Site B for one and half year of exposure
118
4.5
Metal mass loss of Site C for one and half year of exposure
119
4.6
Metal mass loss of Site D for one and half year of exposure
119
4.7
Metal mass loss of Site E for one and half year of exposure
120
4.8
Mass loss for one and half year at research areas
121
4.9
Average mass loss for 1.5 years at five research areas
121
4.10
Statistical model development flowchart
123
4.11
Linear regression between MLC1 and PHC1
134
4.12
Linear regression between MLC1 and LogCLC1
134
4.13
Linear regression analysis of SOC1
135
4.14
Linear regression analysis of SC1
135
4.15
Linear regression analysis of LogREC1
136
4.16
Linear regression analysis of WCC1
136
4.17
Linear regression of CCC1
137
4.18
Linear regression of PIC1
137
4.19
Linear regression of LogORGC1
138
4.20
Linear regression of PSC1 variable
138
4.21
PCA of k coefficient
145
xx
4.22
PCA of v coefficient
145
4.23
Actual mass loss versus predicted model
150
5.1
Location of Component 2 research area
157
5.2
Metal mass loss of Type 1 (Site A) for 1.25 years of exposure
163
5.3
Metal mass loss of Type 2 (Site A) for 1.25 years of exposure
163
5.4
Metal mass loss of Type 3 (Site B) for 1.25 years of exposure
164
5.5
Metal mass loss of Type 4 (Site C) for 1.25 years of exposure
164
5.6
Metal mass loss of Type 5 (Site C) for 1.25 years of exposure
165
5.7
Metal mass loss of Type 6 (Site D) for 1.25 years of exposure
165
5.8
Metal mass loss of Type 7 (Site E) for 1.25 years of exposure
166
5.9
Mass loss for 1.25 years at research areas
167
5.10
Average mass loss for 1.25 years at five research areas
168
5.11
Flowchart of empirical model analysis
169
5.12
Linear regression between MLC2 and PHC2
179
5.13
Linear regression between MLC2 and LogCLC2
179
5.14
Linear regression between MLC2 and SOC2
180
5.15
Linear regression between MLC2 and SC2
180
5.16
Linear regression between MLC2 and LogREC2
181
5.17
Linear regression between MLC2 and WCC2
181
5.18
Linear regression between MLC2 and CCC2
182
5.19
Linear regression between MLC2 and PIC2
182
5.20
Linear regression between MLC2 and LogORGC2
183
5.21
Linear regression between MLC2 and PSC2
183
5.22
PCA of k coefficient
187
5.23
PCA of v coefficient
187
5.24
Actual mass loss versus predicted model
192
6.1
Flowchart of OFAT approaches
197
6.2
Metal mass loss as a function of time for soil pH variable
209
6.3
Metal mass loss as a function of time for soil chloride variable
211
6.4
Metal mass loss as a function of time for soil sulphate content
variable
6.5
213
Metal mass loss as a function of time for soil organic content
variable
214
xxi
6.6
Metal loss rate as a function of time for soil moisture content
variable
216
6.7
Metal loss rate as a function of time for soil clay content variable
217
6.8
Metal loss rate as a function of time for soil plasticity index
variable
219
6.9
Metal loss rate as a function of time for soil particle size variable
220
7.1
Prediction results of Component 1 data using Component 2 model
241
8.1
Flowchart of research outcome
246
xxii
LIST OF ABBREVIATIONS
5L
-
Specification for line pipe
AFAT
-
All-factor-at-a-time
APB
-
Acid-producing bacteria
API
-
American Petroleum Institute
ANOVA
-
Analysis of variance
ASTM
-
American standard test anad materials
C
-
Constant (8760 x 10 cm/y)
C1
-
Component 1
C2
-
Component 2
CC
-
Clay content
CaSO4
-
Calcium sulphate
2
-
Centimetre square
cm
-
Centimetre
CL
-
Chloride content
CLR
-
Corrosion loss rate
CP
-
Cathodic protection
CR
-
Corrosion rate
Co
-
Cobalt
Cr
-
Chromium
DO
-
Dissolved oxygen
e.g.
-
For example
EDA
-
Exploratory data analysis
exp
-
exponent
E
-
East
Fe2+
-
Ferrous ion
Fe2O3.H2O
-
Hydrated ferrous oxide (brown rust)
FBE
-
Fusion bonded epoxy
cm
xxiii
Fe
-
Iron (element)
Fe(OH)2
-
Ferrous hydroxide
Fe(OH)2
-
Ferric hydroxide
FeS
-
Ferum sulphide
GDS
-
Glow discharge spectrometer
GPP
-
Gas processing plant
H+
-
Hydron
Ha
-
Alternative hypothesis
HSD
-
Honestly Significant Difference
Ho
-
Null hypothesis
H2O
-
Water oxygen
H2S
-
Hydrogen sulphide
HCI
-
Hydrochloric acid
ICCP
-
Impressed current cathodic protection
ILI
-
In-line Inspection
K-S
-
Kolmogorov-Smirnov
ksi
-
Kilopounds per square inch
Kn
-
Constant
KMO
-
Kaiser-Meyer-Olkin
LL
-
Liquid limit
log
-
logarithma
m
-
metre
M
-
molar
Max
-
Maximum
Med
-
median
mg/kg
-
Miligram per kilogram
MIC
-
Microbiologically influenced corrosion
ml
-
mililitre
ML
-
Metal mass loss
mm/y
-
Milimetres per year
MRA
-
Multiple regression analysis
mmscf
-
Millions of standard cubic feet
Na+
-
Sodium ion
xxiv
NaCl
-
Sodium chloride/ natrium chloride
NaOH
-
Sodium hydroxide
NHE
-
Normal hydrogen electrode
Ni
-
Nickel
O2
-
Oxygen
OFAT
-
One-factor-at-a-time
OH-
-
Hydroxyl ion
ORG
-
Organic content
ORP
-
Oxidation-reduction potential
P/S
-
Pipe-to-soil
P-value
-
Probability value
Pc
-
Corrosion pit dimension / environmental variables
PCA
-
Principal component analysis
Pmax,cal
-
Predicted value of measured pit depth
PGB
-
Petronas Gas Berhad
PGU
-
Peninsular Gas Utilisation
PI
-
Plasticity index
PIAM
-
Pipeline integrity assessment and management
PS
-
Particle size distribution
PL
-
Plastic limit
R2
-
Coefficient of determination
RES / Re
-
Resistivity
ROW
-
Right-of-way
S-W
-
Shapiro-Wilk
S
-
Sulphide
SCC
-
Stress corrosion cracking
SL
-
Shrinkage limit
-
Single linear regression
-
Sulphate ion
SO
-
Sulphate
Std. dev.
-
Standard deviation
SRB
-
Sulphate-reducing bacteria
T
-
Time of exposure
SLR
SO4
2-
xxv
Tcf
-
Trillion cubic feet
UTM
-
Universiti Teknologi Malaysia
V
-
Voltage
WC
-
Moisture content
X70
-
Pipe having a minimum yield strength of 70ksi
XLSTAT
-
Statistical software suite for Microsoft excel
xxvi
LIST OF SYMBOLS
%
-
Percentage
ºC
-
Degree celcius
ρ
-
Resistivity
Ω
-
Ohm
A
-
Regression coefficient / area of exposure
b1, b2, b3...bn
-
Coefficient of predictor variables
b
-
Power coefficient
d
-
Pit depth
d
-
Steel density
D
-
Steel density in g/cm3
dmax
-
Maximum pit depth
-
e
-
electron
Eh
-
Oxidation-reduction potential
k
-
Metal loss constant
l
-
length
n
-
Corrosion growth pattern constant
t
-
Exposure time / thickness
to
-
Initial time of exposure
v
-
Corrosion growth pattern constant
w
-
width
Wo
-
Initial weight
Wi
-
Final weight loss
x
-
Time exposure
y
-
Dependent variables
xxvii
LIST OF APPENDICES
APPENDIX
TITLE
PAGE
A
Site Layout
261
B
Component 1 Data
267
C
Component 2 Data
298