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Characterizing Change in Web Archiving (open access)

Characterizing Change in Web Archiving

This report attempts to define the characteristics and dimensions of change in web content
Date: August 27, 2004
Creator: Boyko, Andrew
System: The UNT Digital Library
CT Scan of NASA Booster Nozzle (open access)

CT Scan of NASA Booster Nozzle

We scanned a Booster Nozzle for NASA with our 9 meV LINAC, AmSi panel scanner. Three scans were performed using different filtering schemes and different positions of the nozzle. The results of the scan presented here are taken from the scan which provided the best contrast and lowest noise of the three. Our inspection data shows a number of indications of voids in the outer coating of rubber/carbon. The voids are mostly on the side of the nozzle, but a few small voids are present at the ends of the nozzle. We saw no large voids in the adhesive layer between the Aluminum and the inner layer of carbon. This 3D inspection data did show some variation in the size of the adhesive layer, but none of the indications were larger than 3 pixels in extent (21 mils). We have developed a variety of contour estimation and extraction techniques for inspecting small spaces between layers. These tools might work directly on un-sectioned nozzles since the circular contours will fit with our tools a little better. Consequently, it would be useful to scan a full nozzle to ensure there are no untoward degradations in data quality, and to see if our …
Date: July 27, 2004
Creator: Schneberk, D; Perry, R & Thompson, R
System: The UNT Digital Library
Science and Technology Review October 2004 (open access)

Science and Technology Review October 2004

None
Date: August 27, 2004
Creator: Henson, V. E.
System: The UNT Digital Library
Manufacturing Ultra-Precision Meso-Scale Targets by Coining Summary Report (open access)

Manufacturing Ultra-Precision Meso-Scale Targets by Coining Summary Report

There exists a certain type of high energy density physics experiment that requires a very precise, one or two-dimensional sinusoidal pattern to be imprinted on the surface of a thin disc-shaped specimen. Early discussions of potential fabrication processes included precision lapping using a substrate with the sinusoidal patterns, diamond turning, and various vapor deposition techniques. The process of coining, in which the sinusoidal pattern is pressed into the surface of a flat disc, was also proposed. Extensive discussions indicated that the low cost of coining and likelihood of success warranted this proof-of-principal investigation.
Date: July 27, 2004
Creator: Davis, P J; Wall, M A; Hodge, N E & Schwartz, A J
System: The UNT Digital Library
Welding Stainless Steels and Refractory Metals Using Diode-Pumped Continuous Wave Nd:YAG Lasers (open access)

Welding Stainless Steels and Refractory Metals Using Diode-Pumped Continuous Wave Nd:YAG Lasers

This report provides an overview of a series of developmental welding studies performed on a 2.2 kW Rofin Sinar DY-022 Diode Pumped Continuous Wave (CW) Nd:YAG welder at Lawrence Livermore National Laboratory (LLNL). Several materials systems, ranging from refractory metals, such as commercially pure tantalum and vanadium, to austenitic stainless steels, including both 304L and 21-6-9 grades, are examined. Power input and travel speed are systematically varied during the welding of each materials system, and the width, depth, and cross sectional area of the resulting weld fusion zones are measured. These individual studies are undertaken in order to characterize the response of the welder to changes in these welding parameters for a range of materials and to determine the maximum depth of penetration of which this welder is capable in each materials system. The maximum weld depths, which are on the order of 5.4 mm, are observed in the 21-6-9 austenitic stainless steel at the maximum laser power setting (2200 W) and a slow travel speed (6.4 mm/sec). The next highest weld depth is observed in the 304L stainless steel, followed by that observed in the vanadium and, finally, in the tantalum. Porosity, which is attributed to the collapse of …
Date: September 27, 2004
Creator: Palmer, T A; Elmer, J W; Pong, R & Gauthier, M D
System: The UNT Digital Library
Benefit/Cost Ratio in Systems Engineering: Integrated Models, Tests, Design, and Production (open access)

Benefit/Cost Ratio in Systems Engineering: Integrated Models, Tests, Design, and Production

We have previously described our methodology for quantification of risk and risk reduction, and the use of risk, quantified as a dollar value, in the Value Engineering and decision tradeoff process. In this work we extend our example theme of the safety of reactive materials during accidental impacts. We have begun to place the validation of our impact safety model into a systems engineering context. In that sense, we have made connections between the data and the trends in the data, our models of the impact safety process, and the implications regarding confidence levels and reliability based on given impact safety requirements. We have folded this information into a quantitative risk assessment, and shown the assessed risk reduction value of developing an even better model, with more model work or more experimental data or both. Since there is a cost incurred for either model improvement or testing, we have used a Benefit/Cost Ratio metric to quantify this, where Benefit is our quantification of assessed risk reduction, and cost is the cost of the new test data, code development, and model validation. This has left us with further questions posed for our evolving system engineering representation for impact safety and its …
Date: October 27, 2004
Creator: Nitta, C; Logan, R; Chidester, S & Foltz, M F
System: The UNT Digital Library
Soil Sampling and Analysis Plan for the McGee Ranch-Riverlands and North Slope Units of the Hanford Reach National Monument (open access)

Soil Sampling and Analysis Plan for the McGee Ranch-Riverlands and North Slope Units of the Hanford Reach National Monument

This document describes soil sampling that will be performed by Pacific Northwest National Laboratory's Surface Environmental Surveillance Project on two units of the Hanford Reach National Monument: the McGee Ranch-Riverlands Unit (Riverlands Unit) and the North Slope made up of the Saddle Mountain Unit and the Wahluke Slope Unit. This sampling fulfills a U.S. Department of Energy requirement to evaluate the potential for residual radioactive contamination on this land and determine compliance with the requirements of DOE Order 5400.5 prior to radiological release of the property.
Date: December 27, 2004
Creator: Fritz, Brad G. & Dirkes, Roger L.
System: The UNT Digital Library
Preliminary Report on Coining of Targets (open access)

Preliminary Report on Coining of Targets

We were tasked with developing a coining technique that would evaluate the feasibility of using a pressing, or coining process to imprint a one-dimensional sinusoidal pattern onto a thin disk specimen. We performed finite element method simulations of the coining process, designed, built, and tested a coining apparatus and tested surrogate materials, and coined a sample of special nuclear material. The preliminary results were encouraging. The pressing of a 3-mm diameter by {approx}100 {micro}m thick disc to 500 pounds of pressure produced a flat part with a 1-{micro}m deep by 50-{micro}m period sine wave pattern covering all of the surface and thus demonstrated the method for replicating ultraprecision, mesoscale features onto a near-net-shape metallic blank. This coining technique is being developed to provide specialty processing for the manufacturing of difficult to machine, millimeter-size components made from materials that present hazardous conditions. The technology is versatile and can be used to imprint a wide range of features, or profiles into two opposing surfaces. The coining process requires a simple, conceivably hand held tool, which efficiently produces ultra-precision work pieces without the production of byproducts such as machining chips, or grinding swarf. It shows promise for use on ductile materials that cannot …
Date: July 27, 2004
Creator: Davis, P; Wall, M; Hodge, N & Schwartz, A
System: The UNT Digital Library
LSST data pipeline prototyping plans and strategy (open access)

LSST data pipeline prototyping plans and strategy

In this document we describe our approach and strategy for building the prototype for the image-stream analysis data pipeline. We start by describing the main research areas upon which we will be focusing; we then describe our plans on how to carry these research ideas to implement the data pipeline.
Date: May 27, 2004
Creator: Abdulla, G. M.; Brase, J.; Cook, K. & Miller, M.
System: The UNT Digital Library
Development of Wet-Etching Tools for Precision Optical Figuring (open access)

Development of Wet-Etching Tools for Precision Optical Figuring

This FY03 final report on Wet Etch Figuring involves a 2D thermal tool. Its purpose is to flatten (0.3 to 1 mm thickness) sheets of glass faster thus cheaper than conventional sub aperture tools. An array of resistors on a circuit board was used to heat acid over the glass Optical Path Difference (OPD) thick spots and at times this heating extended over the most of the glass aperture. Where the acid is heated on the glass it dissolves faster. A self-referencing interferometer measured the glass thickness, its design taking advantage of the parallel nature and thinness of these glass sheets. This measurement is used in close loop control of the heating patterns of the circuit board thus glass and acid. Only the glass and acid were to be moved to make the tool logistically simple to use in mass production. A set of 4-circuit board, covering 80 x 80-cm aperture was ordered, but only one 40 x 40-cm board was put together and tested for this report. The interferometer measurement of glass OPD was slower than needed on some glass profiles. Sometimes the interference fringes were too fine to resolve which would alias the sign of the glass thickness …
Date: January 27, 2004
Creator: Rushford, M C; Dixit, S N; Hyde, R; Britten, J A; Nissen, J; Aasen, M et al.
System: The UNT Digital Library
Two-parameter Failure Model Improves Time-independent and Time-dependent Failure Predictions (open access)

Two-parameter Failure Model Improves Time-independent and Time-dependent Failure Predictions

A new analytical model for predicting failure under a generalized, triaxial stress state was developed by the author and initially reported in 1984. The model was validated for predicting failure under elevated-temperature creep-rupture conditions. Biaxial data for three alloy steels, Types 304 and 316 stainless steels and Inconel 600, demonstrated two to three orders of magnitude reduction in the scatter of predicted versus observed creep-rupture times as compared to the classical failure models of Mises, Tresca, and Rankine. In 1990, the new model was incorporated into American Society of Mechanical Engineers (ASME) Code Case N47-29 for design of components operating under creep-rupture conditions. The current report provides additional validation of the model for predicting failure under time-independent conditions and also outlines a methodology for predicting failure under cyclic, time-dependent, creep-fatigue conditions. The later extension of the methodology may have the potential to improve failure predictions there as well. These results are relevant to most design applications, but they have special relevance to high-performance design applications such as components for high-pressure equipment, nuclear reactors, and jet engines.
Date: January 27, 2004
Creator: Huddleston, R L
System: The UNT Digital Library
Applicability of the Spin-orbit Sum Rule for the Actinide 5? States (open access)

Applicability of the Spin-orbit Sum Rule for the Actinide 5? States

The branching ratio of core-valence transitions in x-ray absorption spectroscopy and electron energy loss spectroscopy is linearly related to the expectation value of the spin-orbit operator of the valence states. Here, we analyze the measured branching ratio of the N{sub 4,5} edges acquired by electron energy-loss spectroscopy in a transmission electron microscope, and synchrotron-radiation-based x-ray absorption. Results show that the spin-orbit sum rule can be applied to actinide 5f states, where the accuracy can be increased using the correction term obtained from atomic many-electron calculations.
Date: January 27, 2004
Creator: Chung, B. W.; Tobin, J. G.; Moore, K. T.; van der Laan, G.; Schwartz, A. J. & Wall, M. A.
System: The UNT Digital Library
The Confederated Tribes of the Warm Springs Indian Reservation of Oregon John Day Basin Office : Watershed Restoration Projects : 2003 Annual Report. (open access)

The Confederated Tribes of the Warm Springs Indian Reservation of Oregon John Day Basin Office : Watershed Restoration Projects : 2003 Annual Report.

The John Day is the nation's second longest free-flowing river in the contiguous United States and the longest containing entirely unsupplemented runs of anadromous fish. Located in eastern Oregon, the basin drains over 8,000 square miles, Oregon's fourth largest drainage basin, and incorporates portions of eleven counties. Originating in the Strawberry Mountains near Prairie City, the John Day River flows 284 miles in a northwesterly direction, entering the Columbia River approximately four miles upstream of the John Day dam. With wild runs of spring Chinook salmon and summer steelhead, westslope cutthroat, and redband and bull trout, the John Day system is truly a basin with national significance. The majority of the John Day basin was ceded to the Federal government in 1855 by the Confederated Tribes of the Warm Springs Reservation of Oregon (Tribes). In 1997, the Tribes established an office in the basin to coordinate restoration projects, monitoring, planning and other watershed activities on private and public lands. Once established, the John Day Basin Office (JDBO) formed a partnership with the Grant Soil and Water Conservation District (GSWCD), which contracts the majority of the construction implementation activities for these projects from the JDBO. The GSWCD completes the landowner contact, …
Date: February 27, 2004
Creator: Office., Confederated Tribes of the Warm Springs Reservation of Oregon. John Day Basin
System: The UNT Digital Library
Atomistic Processes of Catalyst Degradation (open access)

Atomistic Processes of Catalyst Degradation

The purpose of this cooperative research and development agreement (CRADA) between Sasol North America, Inc., and the oak Ridge National Laboratory (ORNL) was to improve the stability of alumina-based industrial catalysts through the combination of aberration-corrected scanning transmission electron microscopy (STEM) at ORNL and innovative sample preparation techniques at Sasol. Outstanding progress has been made in task 1, 'Atomistic processes of La stabilization'. STEM investigations provided structural information with single-atom precision, showing the lattice location of La dopant atoms, thus enabling first-principles calculations of binding energies, which were performed in collaboration with Vanderbilt University. The stabilization mechanism turns out to be entirely due to a particularly strong binding energy of the La tom to the {gamma}-alumina surface. The large size of the La atom precludes incorporation of La into the bulk alumina and also strains the surface, thus preventing any clustering of La atoms. Thus highly disperse distribution is achieved and confirmed by STEM images. la also affects relative stability of the exposed surfaces of {gamma}-alumina, making the 100 surface more stable for the doped case, unlike the 110 surface for pure {gamma}-alumina. From the first-principles calculations, they can estimate the increase in transition temperature for the 3% loading of …
Date: November 27, 2004
Creator: unknown
System: The UNT Digital Library
Metals Processing Laboratory Users (MPLUS) Facility Annual Report FY 2002 (October 1, 2001-September 30, 2002) (open access)

Metals Processing Laboratory Users (MPLUS) Facility Annual Report FY 2002 (October 1, 2001-September 30, 2002)

The Metals Processing Laboratory Users Facility (MPLUS) is a Department of Energy (DOE), Energy Efficiency and Renewable Energy, Industrial Technologies Program, user facility designated to assist researchers in key industries, universities, and federal laboratories in improving energy efficiency, improving environmental aspects, and increasing competitiveness. The goal of MPLUS is to provide access to the specialized technical expertise and equipment needed to solve metals processing issues that limit the development and implementation of emerging metals processing technologies. The scope of work can also extend to other types of materials. MPLUS has four primary user centers: (1) Processing--casting, powder metallurgy, deformation processing (including extrusion, forging, rolling), melting, thermomechanical processing, and high-density infrared processing; (2) Joining--welding, monitoring and control, solidification, brazing, and bonding; (3) Characterization--corrosion, mechanical properties, fracture mechanics, microstructure, nondestructive examination, computer-controlled dilatometry, and emissivity; and (4) Materials/Process Modeling--mathematical design and analyses, high-performance computing, process modeling, solidification/deformation, microstructure evolution, thermodynamic and kinetic, and materials databases A fully integrated approach provides researchers with unique opportunities to address technologically related issues to solve metals processing problems and probe new technologies. Access is also available to 16 additional Oak Ridge National Laboratory (ORNL) user facilities ranging from state-of-the-art materials characterization capabilities, and high-performance computing to …
Date: April 27, 2004
Creator: Angelini, P
System: The UNT Digital Library
Advanced Reactor Licensing: Experience with Digital I&C Technology in Evolutionary Plants (open access)

Advanced Reactor Licensing: Experience with Digital I&C Technology in Evolutionary Plants

This report presents the findings from a study of experience with digital instrumentation and controls (I&C) technology in evolutionary nuclear power plants. In particular, this study evaluated regulatory approaches employed by the international nuclear power community for licensing advanced l&C systems and identified lessons learned. The report (1) gives an overview of the modern l&C technologies employed at numerous evolutionary nuclear power plants, (2) identifies performance experience derived from those applications, (3) discusses regulatory processes employed and issues that have arisen, (4) captures lessons learned from performance and regulatory experience, (5) suggests anticipated issues that may arise from international near-term deployment of reactor concepts, and (6) offers conclusions and recommendations for potential activities to support advanced reactor licensing in the United States.
Date: September 27, 2004
Creator: Wood, RT
System: The UNT Digital Library
THERMAL CONDUCTIVITY OF THE POTENTIAL REPOSITORY HORIZON (open access)

THERMAL CONDUCTIVITY OF THE POTENTIAL REPOSITORY HORIZON

The primary purpose of this report is to assess the spatial variability and uncertainty of bulk thermal conductivity in the host horizon for the repository at Yucca Mountain. More specifically, the lithostratigraphic units studied are located within the Topopah Spring Tuff (Tpt) and consist of the upper lithophysal zone (Tptpul), the middle nonlithophysal zone (Tptpmn), the lower lithophysal zone (Tptpll), and the lower nonlithophysal zone (Tptpln). Design plans indicate that approximately 81 percent of the repository will be excavated in the Tptpll, approximately 12 percent in the Tptpmn, and the remainder in the Tptul and Tptpln (BSC 2004 [DIRS 168370]). This report provides three-dimensional geostatistical estimates of the bulk thermal conductivity for the four stratigraphic layers of the repository horizon. The three-dimensional geostatistical estimates of matrix and lithophysal porosity, dry bulk density, and matrix thermal conductivity are also provided. This report provides input to various models and calculations that simulate heat transport through the rock mass. These models include the ''Drift Degradation Analysis, Multiscale Thermohydrologic Model, Ventilation Model and Analysis Report, Igneous Intrusion Impacts on Waste Packages and Waste Forms, Drift-Scale Coupled Processes (DST and TH Seepage) Models'', and ''Drift Scale THM Model''. These models directly or indirectly provide input …
Date: September 27, 2004
Creator: BEAN, J.E.
System: The UNT Digital Library
Dynamic Testing of Gasifier Refractory (open access)

Dynamic Testing of Gasifier Refractory

The University of North Dakota (UND) Chemical Engineering Department in conjunction with the UND Energy & Environmental Research Center (EERC) have initiated a program to thoroughly examine the combined chemical (reaction and phase change) and physical (erosion) effects experienced by a variety of refractory materials during both normal operation and thermal cycling under slagging coal gasification conditions. The goal of this work is to devise a mechanism of refractory loss under these conditions. The controlled-atmospheric dynamic corrodent application furnace (CADCAF) is being utilized to simulate refractory/slag interactions under dynamic conditions that more realistically simulate the environment in a slagging coal gasifier than any of the static tests used previously by refractory manufacturers and researchers. Shakedown testing of the CADCAF has been completed. Samples of slag and refractory from the Tampa Electric Polk Power Station have been obtained for testing in the CADCAF. The slag has been dried and sieved to the size needed for our flowing slag corrosion tests. Screening tests are in currently in progress. Detailed analysis of corrosion rates from the first tests is in progress.
Date: September 27, 2004
Creator: Mann, Michael D.; Shukla, Devdutt; Hong, Xi & Hurley, John P.
System: The UNT Digital Library
Improving CO2 Efficiency for Recovering Oil in Heterogeneous Reservoirs (open access)

Improving CO2 Efficiency for Recovering Oil in Heterogeneous Reservoirs

A three-year contract for the project, DOE Contract No. DE-FG26-01BC15364, ''Improving CO{sub 2} Efficiency for Recovering Oil in Heterogeneous Reservoirs'', was started on September 28, 2001. This project examines three major areas in which CO{sub 2} flooding can be improved: fluid and matrix interactions, conformance control/sweep efficiency, and reservoir simulation for improved oil recovery. The project has received a one-year, no-cost extension to September 27, 2005. During this extra time additional deliverables will be (1) the version of MASTER that has been debugged and a foam option added for CO{sub 2} mobility control and (2) adsorption/desorption data on pure component minerals common in reservoir rock that will be used to improve predictions of chemical loss to adsorption in reservoirs. This report discusses the activity during the six-month period covering October 1, 2003 through March 31, 2004 that comprises the first and second fiscal quarters of the project's third year. During this period of the project several areas have advanced: reservoir fluid/rock interactions and their relationships to changing injectivity, and surfactant adsorption on quarried core and pure component granules, foam stability, and high flow rate effects. Presentations and papers included: a papers covered in a previous report was presented at the …
Date: March 27, 2004
Creator: Grigg, Reid B.; Svec, Robert K.; Zeng, Zheng-Wen; Yi, Liu & Bai, Baojun
System: The UNT Digital Library
Improving CO2 Efficiency for Recovering Oil in Heterogeneous Reservoirs (open access)

Improving CO2 Efficiency for Recovering Oil in Heterogeneous Reservoirs

The third annual report of ''Improving CO{sub 2} Efficiency for Recovery Oil in Heterogeneous Reservoirs'' presents results of laboratory studies with related analytical models for improved oil recovery. All studies were designed to optimize utilization and extend the practice of CO{sub 2} flooding to a wider range of reservoirs. Chapter 1 describes the behavior at low concentrations of the surfactant Chaser International CD1045{trademark} (CD) versus different salinity, pressure and temperature. Results of studies on the effects of pH and polymer (hydrolyzed polyacrylamide?HPAM) and CO{sub 2} foam stability after adsorption in the core are also reported. Calcium lignosulfonate (CLS) transport mechanisms through sandstone, description of the adsorption of CD and CD/CLS onto three porous media (sandstone, limestone and dolomite) and five minerals, and the effect of adsorption on foam stability are also reported. In Chapter 2, the adsorption kinetics of CLS in porous Berea sandstone and non-porous minerals are compared by monitoring adsorption density change with time. Results show that adsorption requires a much longer time for the porous versus non-porous medium. CLS adsorption onto sandstone can be divided into three regions: adsorption controlled by dispersion, adsorption controlled by diffusion and adsorption equilibrium. NaI tracer used to characterize the sandstone had …
Date: September 27, 2004
Creator: Grigg, Reid B.; Svec, Robert K.; Zeng, Zhengwen; Bai, Baojun & Liu, Yi
System: The UNT Digital Library
SATURATED ZONE FLOW AND TRANSPORT MODEL ABSTRACTION (open access)

SATURATED ZONE FLOW AND TRANSPORT MODEL ABSTRACTION

The purpose of the saturated zone (SZ) flow and transport model abstraction task is to provide radionuclide-transport simulation results for use in the total system performance assessment (TSPA) for license application (LA) calculations. This task includes assessment of uncertainty in parameters that pertain to both groundwater flow and radionuclide transport in the models used for this purpose. This model report documents the following: (1) The SZ transport abstraction model, which consists of a set of radionuclide breakthrough curves at the accessible environment for use in the TSPA-LA simulations of radionuclide releases into the biosphere. These radionuclide breakthrough curves contain information on radionuclide-transport times through the SZ. (2) The SZ one-dimensional (I-D) transport model, which is incorporated in the TSPA-LA model to simulate the transport, decay, and ingrowth of radionuclide decay chains in the SZ. (3) The analysis of uncertainty in groundwater-flow and radionuclide-transport input parameters for the SZ transport abstraction model and the SZ 1-D transport model. (4) The analysis of the background concentration of alpha-emitting species in the groundwater of the SZ.
Date: October 27, 2004
Creator: ARNOLD, B.W.
System: The UNT Digital Library
Metals Processing Laboratory Users (MPLUS) Facility Annual Report: October 1, 2000 through September 30, 2001 (open access)

Metals Processing Laboratory Users (MPLUS) Facility Annual Report: October 1, 2000 through September 30, 2001

The Metals Processing Laboratory Users Facility (MPLUS) is a Department of Energy (DOE), Energy Efficiency and Renewable Energy, Industrial Technologies Program user facility designated to assist researchers in key industries, universities, and federal laboratories in improving energy efficiency, improving environmental aspects, and increasing competitiveness. The goal of MPLUS is to provide access to the specialized technical expertise and equipment needed to solve metals processing issues that limit the development and implementation of emerging metals processing technologies. The scope of work can also extend to other types of materials. MPLUS has four primary User Centers including: (1) Processing--casting, powder metallurgy, deformation processing including (extrusion, forging, rolling), melting, thermomechanical processing, high density infrared processing; (2) Joining--welding, monitoring and control, solidification, brazing, bonding; (3) Characterization--corrosion, mechanical properties, fracture mechanics, microstructure, nondestructive examination, computer-controlled dilatometry, and emissivity; (4) Materials/Process Modeling--mathematical design and analyses, high performance computing, process modeling, solidification/deformation, microstructure evolution, thermodynamic and kinetic, and materials data bases. A fully integrated approach provides researchers with unique opportunities to address technologically related issues to solve metals processing problems and probe new technologies. Access is also available to 16 additional Oak Ridge National Laboratory (ORNL) user facilities ranging from state of the art materials characterization capabilities, …
Date: April 27, 2004
Creator: Angelini, P
System: The UNT Digital Library
THERMAL TESTING MEASUREMENTS REPORT (open access)

THERMAL TESTING MEASUREMENTS REPORT

None
Date: September 27, 2004
Creator: ASHLEY, D.A. & JONES, R.L.
System: The UNT Digital Library
Correlation of Process Data and Electrocheical Noise to Assess Kraft Digester Corrosion: Second Year at Spring Grove (open access)

Correlation of Process Data and Electrocheical Noise to Assess Kraft Digester Corrosion: Second Year at Spring Grove

Electrochemical noise (EN) probes were deployed in the carbon steel continuous kraft digester at Spring Grove at four locations and at one location in the bottom cone of the associated flash tank for a second consecutive year of a corrosion study. The probes contained dual electrodes of 309LSi stainless steel overlay--representing a field repair material applied to a portion of the vessel--and dual electrodes of 312 stainless steel overlay. Current and potential noise, the temperature at each probe location, and the value of 23 process parameters (flow rates, liquor chemistry, etc.) were again monitored continuously for a period of almost one year. Historical vessel inspection data and post-test evaluation of the probe components were used to assess/compare EN corrosion activity with physical changes in wall thickness and corrosion patterns on the digester shell. In addition, attempts were made to correlate EN activity from each electrode type with process parameters. The results indicate the corrosion conditions aggressive to mild steel persist within the digester, as post-test inspection of the vessel revealed localized corrosion of mild steel in locations previously free of attack. Further, there was evidence that the depth of localized attack of exposed steel had increased in some locations. Nevertheless, …
Date: April 27, 2004
Creator: Pawel, SJ
System: The UNT Digital Library