Underground Corrosion Model of Steel Pipelines Using In Situ Parameters of Soil

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Siti Nor Fariza Mior Mohd Tahir ◽  
Nordin Yahaya ◽  
Norhazilan Md Noor ◽  
Lim Kar Sing ◽  
Azlan Abdul Rahman
Keyword(s):  
Time Dependence ◽  
Principal Component ◽  
Chloride Content ◽  
Soil Parameters ◽  
Metal Loss ◽  
Underground Structures ◽  
Underground Pipelines ◽  
Linear Correlation Analysis ◽  
Underground Corrosion

A simple yet practical model to estimate the time dependence of metal loss (ML) in underground pipelines has been developed considering the in situ soil parameters. These parameters are soil resistivity, pH, moisture content, chloride content, and salinity. The time dependence of the ML was modeled as Pmax = ktn, where t is the time exposure, k is ML constant, and n is the corrosion growth pattern. The results of ML and in situ parameters were analyzed using statistical methods such as data screening, linear correlation analysis, principal component analysis, and multiple linear regressions. The best model revealed that k is principally influenced by ressistivity, and n appears to be correlated with chloride content. Model optimization was carried out by introducing several observation criteria, namely, water access, soil color, and soil texture. The addition of these factors has improved the initial accuracy of model to an R2 score of 0.960. As a conclusion, the developed model can provide immediate assessment of corrosion growth experienced by underground structures.

Modeling of External Metal Loss for Corroded Buried Pipeline

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Siti Rabeah Othman ◽  
Nordin Yahaya ◽  
Norhazilan Md Noor ◽  
Lim Kar Sing ◽  
Libriati Zardasti ◽  
...  
Keyword(s):  
Linear Regression ◽  
Moisture Content ◽  
Time Dependence ◽  
Mass Loss ◽  
Chemical Properties ◽  
Principal Component ◽  
Clay Content ◽  
Organic Content ◽  
Plasticity Index ◽  
Metal Loss

A statistical predictive model to estimate the time dependence of metal loss (ML) for buried pipelines has been developed considering the physical and chemical properties of soil. The parameters for this model include pH, chloride content, caliphate content (SO), sulfide content, organic content (ORG), resistivity (RE), moisture content (WC), clay content (CC), plasticity index (PI), and particle size distribution. The power law-based time dependence of the ML was modeled as P = ktv, where t is the time exposure, k is the metal loss coefficient, and v is the corrosion growth pattern. The results were analyzed using statistical methods such as exploratory data analysis (EDA), single linear regression (SLR), principal component analysis (PCA), and multiple linear regression (MLR). The model revealed that chloride (CL), resistivity (RE), organic content (ORG), moisture content (WC), and pH were the most influential variables on k, while caliphate content (SO), plasticity index (PI), and clay content (CC) appear to be influential toward v. The predictive corrosion model based on data from a real site has yielded a reasonable prediction of metal mass loss, with an R2 score of 0.89. This research has introduced innovative ways to model the corrosion growth for an underground pipeline environment using measured metal loss from multiple pipeline installation sites. The model enables predictions of potential metal mass loss and hence the level of soil corrosivity for Malaysia.

scholarly journals Relationship Between in-situ Measurement of Soil Parameters and Metal Loss Volume of X70 Carbon Steel Coupon

2015 ◽  
Vol 8 (2) ◽  
pp. 205-211 ◽  
Author(s):  
Siti Nor Fariza Mior Tahir ◽  
Norhazilan Md Noor ◽  
Nordin Yahaya ◽  
Lim Kar Sing
Keyword(s):  
Carbon Steel ◽  
In Situ Measurement ◽  
Soil Parameters ◽  
Metal Loss ◽  
Steel Coupon

scholarly journals Development of the Statistical Model for Monitoring Salinization in the Mekong Delta of Vietnam Using Remote Sensing Data and In-Situ Measurements

Proceedings ◽  
2018 ◽  
Vol 2 (10) ◽  
pp. 565
Author(s):  
Nguyen Nguyen Vu ◽  
Le Van Trung ◽  
Tran Thi Van
Keyword(s):  
Statistical Model ◽  
Mekong Delta ◽  
Remote Sensing Data ◽  
Principal Component ◽  
Measured Data ◽  
In Situ Measurements ◽  
Landsat 8 ◽  
Spectral Bands ◽  
Component Band

This article presents the methodology for developing a statistical model for monitoring salinity intrusion in the Mekong Delta based on the integration of satellite imagery and in-situ measurements. We used Landsat-8 Operational Land Imager and Thermal Infrared Sensor (Landsat- 8 OLI and TIRS) satellite data to establish the relationship between the planetary reflectance and the ground measured data in the dry season during 2014. The three spectral bands (blue, green, red) and the principal component band were used to obtain the most suitable models. The selected model showed a good correlation with the exponential function of the principal component band and the ground measured data (R2 > 0.8). Simulation of the salinity distribution along the river shows the intrusion of a 4 g/L salt boundary from the estuary to the inner field of more than 50 km. The developed model will be an active contribution, providing managers with adaptation and response solutions suitable for intrusion in the estuary as well as the inner field of the Mekong Delta.

scholarly journals Development of Fragility Curves for Piping and Slope Stability of River Levees

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 738
Author(s):  
Nicola Rossi ◽  
Mario Bačić ◽  
Meho Saša Kovačević ◽  
Lovorka Librić
Keyword(s):  
Slope Stability ◽  
Fragility Curves ◽  
Safety Margin ◽  
Water Levels ◽  
Flood Event ◽  
Soil Parameters ◽  
Design Code ◽  
A Site ◽  
Insight Into

The design code Eurocode 7 relies on semi-probabilistic calculation procedures, through utilization of the soil parameters obtained by in situ and laboratory tests, or by the means of transformation models. To reach a prescribed safety margin, the inherent soil parameter variability is accounted for through the application of partial factors to either soil parameters directly or to the resistance. However, considering several sources of geotechnical uncertainty, including the inherent soil variability, measurement error and transformation uncertainty, full probabilistic analyses should be implemented to directly consider the site-specific variability. This paper presents the procedure of developing fragility curves for levee slope stability and piping as failure mechanisms that lead to larger breaches, where a direct influence of the flood event intensity on the probability of failure is calculated. A range of fragility curve sets is presented, considering the variability of levee material properties and varying durations of the flood event, thus providing crucial insight into the vulnerability of the levee exposed to rising water levels. The procedure is applied to the River Drava levee, a site which has shown a continuous trend of increased water levels in recent years.

scholarly journals An Automated Pipeline for Dynamic Detection of Sub-Surface Metal Loss Defects across Cold Thermography Images

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4811
Author(s):  
Siavash Doshvarpassand ◽  
Xiangyu Wang
Keyword(s):  
Test Piece ◽  
Surface Defects ◽  
Principal Component ◽  
Specific Area ◽  
Gaussian Mixture ◽  
Metal Loss ◽  
Test Surface ◽  
Thermal Excitation ◽  
Cold Stimulation ◽  
Surface Metal

Utilising cooling stimulation as a thermal excitation means has demonstrated profound capabilities of detecting sub-surface metal loss using thermography. Previously, a prototype mechanism was introduced which accommodates a thermal camera and cooling source and operates in a reciprocating motion scanning the test piece while cold stimulation is in operation. Immediately after that, the camera registers the thermal evolution. However, thermal reflections, non-uniform stimulation and lateral heat diffusions will remain as undesirable phenomena preventing the effective observation of sub-surface defects. This becomes more challenging when there is no prior knowledge of the non-defective area in order to effectively distinguish between defective and non-defective areas. In this work, the previously automated acquisition and processing pipeline is re-designed and optimised for two purposes: 1—Through the previous work, the mentioned pipeline was used to analyse a specific area of the test piece surface in order to reconstruct the reference area and identify defects. In order to expand the application of this device over the entire test area, regardless of its extension, the pipeline is improved in which the final surface image is reconstructed by taking into account multiple segments of the test surface. The previously introduced pre-processing method of Dynamic Reference Reconstruction (DRR) is enhanced by using a more rigorous thresholding procedure. Principal Component Analysis (PCA) is then used in order for feature (DRR images) reduction. 2—The results of PCA on multiple segment images of the test surface revealed different ranges of intensities across each segment image. This potentially could cause mistaken interpretation of the defective and non-defective areas. An automated segmentation method based on Gaussian Mixture Model (GMM) is used to assist the expert user in more effective detection of the defective areas when the non-defective areas are uniformly characterised as background. The final results of GMM have shown not only the capability of accurately detecting subsurface metal loss as low as 37.5% but also the successful detection of defects that were either unidentifiable or invisible in either the original thermal images or their PCA transformed results.

scholarly journals Key soil parameters affecting the survival of Panax notoginseng under continuous cropping

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wumei Xu ◽  
Fengyun Wu ◽  
Haoji Wang ◽  
Linyan Zhao ◽  
Xue Liu ◽  
...  
Keyword(s):  
Soil Ph ◽  
Pearson Correlation ◽  
Principal Component ◽  
Panax Notoginseng ◽  
Soil Parameters ◽  
Continuous Cropping ◽  
Poor Growth ◽  
Available N ◽  
The Poor ◽  
Replant Problem

AbstractNegative plant-soil feedbacks lead to the poor growth of Panax notoginseng (Sanqi), a well-known herb in Asia and has been used worldwide, under continuous cropping. However, the key soil parameters causing the replant problem are still unclear. Here we conducted a field experiment after 5-year continuous cropping. Sanqi seedlings were cultivated in 7 plots (1.5 m × 2 m), which were randomly assigned along a survival gradient. In total, 13 important soil parameters were measured to understand their relationship with Sanqi’s survival. Pearson correlation analysis showed that 6 soil parameters, including phosphatase, urease, cellulase, bacteria/fungi ratio, available N, and pH, were all correlated with Sanqi’s survival rate (P < 0.05). Principal component analysis (PCA) indicated that they explained 61% of the variances based on the first component, with soil pH being closely correlated with other parameters affecting Sanqi’s survival. The optimum pH for Sanqi growth is about 6.5, but the mean soil pH in the study area is 5.27 (4.86–5.68), therefore it is possible to ameliorate the poor growth of Sanqi by increasing soil pH. This study may also help to reduce the replant problem of other crops under continuous cropping since it is widespread in agricultural production.

scholarly journals Black Soldier Fly Larval Valorization Benefitting from Ex-Situ Fungal Fermentation in Reducing Coconut Endosperm Waste

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 275
Author(s):  
Chung Yiin Wong ◽  
Kunlanan Kiatkittipong ◽  
Worapon Kiatkittipong ◽  
Seteno K. O. Ntwampe ◽  
Man Kee Lam ◽  
...  
Keyword(s):  
Principal Component ◽  
Correlation Study ◽  
Statistical Correlation ◽  
Waste Reduction ◽  
Ex Situ ◽  
Larval Feeding ◽  
Rhizopus Oligosporus ◽  
Black Soldier Fly ◽  
The Cost

Oftentimes, the employment of entomoremediation to reduce organic wastes encounters ubiquitous shortcomings, i.e., ineffectiveness to valorize recalcitrant organics in wastes. Considering the cost-favorability, a fermentation process can be employed to facilitate the degradation of biopolymers into smaller organics, easing the subsequent entomoremediation process. However, the efficacy of in situ fermentation was found impeded by the black soldier fly larvae (BSFL) in the current study to reduce coconut endosperm waste (CEW). Indeed, by changing into ex situ fermentation, in which the fungal Rhizopus oligosporus was permitted to execute fermentation on CEW prior to the larval feeding, the reduction of CEW was significantly enhanced. In this regard, the waste reduction index of CEW by BSFL was almost doubled as opposed to in situ fermentation, even with the inoculation of merely 0.5 wt % of Rhizopus oligosporus. Moreover, with only 0.02 wt % of fungal inoculation size to execute the ex situ fermentation on CEW, it could spur BSFL growth by about 50%. Finally, from the statistical correlation study using principal component analysis, the presence of Rhizopus oligosporus in a range of 0.5–1.0 wt % was regarded as optimum to ferment CEW via ex situ mode, prior to the valorization by BSFL in reducing the CEW.

Effects of Stress Path and Stress History on the Stiffness of Reconstituted London Clay

1986 ◽  
Vol 2 (1) ◽  
pp. 139-144 ◽  
Author(s):  
J. H. Atkinson ◽  
J. S. Evans ◽  
D. Richardson
Keyword(s):  
Stress Path ◽  
Triaxial Tests ◽  
Soil Parameters ◽  
Stress History ◽  
Strain Behaviour ◽  
Reconstituted Soil ◽  
Path Dependent ◽  
London Clay ◽  
Soil Behaviour

AbstractSoil behaviour is stress history dependent and stress path dependent and soil parameters, particularly those for stress-strain behaviour, measured in conventional triaxial tests may not represent the behaviour of soil in many civil engineering works.To obtain more realistic parameters it may be necessary to conduct laboratory tests which more closely represent in situ conditions before and during construction.The paper describes equipment developed at The City University to carry out stress path tests simply and economically. A series of CU triaxial tests and stress path tests on reconstituted soil illustrate the dependence of measured soil parameters on stress history and stress path.

scholarly journals Accurate dating of stalagmites from low seasonal contrast tropical Pacific climate using Sr 2D maps, fabrics and annual hydrological cycles

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammadali Faraji ◽  
Andrea Borsato ◽  
Silvia Frisia ◽  
John C. Hellstrom ◽  
Andrew Lorrey ◽  
...  
Keyword(s):  
Principal Component ◽  
Tropical Pacific ◽  
In Situ Monitoring ◽  
Marine Aerosols ◽  
Icp Ms ◽  
Optical Maps ◽  
Hydrological Cycles ◽  
Climate Proxies ◽  
Dimensional Mapping

AbstractTropical Pacific stalagmites are commonly affected by dating uncertainties because of their low U concentration and/or elevated initial 230Th content. This poses problems in establishing reliable trends and periodicities for droughts and pluvial episodes in a region vulnerable to climate change. Here we constrain the chronology of a Cook Islands stalagmite using synchrotron µXRF two-dimensional mapping of Sr concentrations coupled with growth laminae optical imaging constrained by in situ monitoring. Unidimensional LA-ICP-MS-generated Mg, Sr, Ba and Na variability series were anchored to the 2D Sr and optical maps. The annual hydrological significance of Mg, Sr, Ba and Na was tested by principal component analysis, which revealed that Mg and Na are related to dry-season, wind-transported marine aerosols, similar to the host-rock derived Sr and Ba signatures. Trace element annual banding was then used to generate a calendar-year master chronology with a dating uncertainty maximum of ± 15 years over 336 years. Our approach demonstrates that accurate chronologies and coupled hydroclimate proxies can be obtained from speleothems formed in tropical settings where low seasonality and problematic U–Th dating would discourage the use of high-resolution climate proxies datasets.

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