bluuebunny/crossref_metadata_2025 huggingface dataset:
Environmental and Geological Site Characterization in Vegetated Areas: Image Enhancement Guidelines
Authors: Singhroy V
Published: March 2009

Guidelines for environmental and geological site characterization normally include field methods with little attention to remote sensing techniques. This paper provides some useful image enhancement guidelines that will facilitate geological mapping and environmental monitoring of vegetated sites.

Image enhancement techniques for environmental and geological site characterization provide information on land use, vegetation stress, fracture systems, rock types, landforms, surficial materials, moisture and drainage. In areas where the rock units are covered by vegetation and soil/drift cover, it is difficult to delineate rock types and surficial materials unless special image enhancement is performed. Selection of specific sensor characteristics and surface conditions can maximize the image enhancement techniques and therefore provide useful geologic information. This paper provides useful image enhancement techniques for (1) locating areas of vegetation stress related to acid mine drainage from high resolution airborne multispectral images; and for (2) mapping surficial materials, landforms, rock types and fractures from SAR-TM color composites, the selective uses of principal component analysis and spatial filtering techniques of TM and SAR images, and the integration of SAR and magnetics.
Development of a GIS for Environmental Assessment Incorporating Known Potential Environmental Hazards and Remote Sensing
Authors: Shaffer DL , Roth MJS , Ruggles R
Published: March 2009

The development of a Geographic Information System (GIS) application to evaluate potential environmental hazards within the Bushkill watershed in Northampton County, Pennsylvania, is described by the authors. Information identifying hazardous materials used by businesses within the watershed was obtained from databases of the Environmental Protection Agency. These databases were supplemented and updated by visual reconnaissance and by a review of current tax maps, zoning information and aerial photographs. Information regarding the use or storage of substances considered hazardous was collected from various agencies as well as any known violations of environmental regulations by the businesses. Geographic information including remotely sensed data and maps of surface water bodies, geology and soil types was also obtained for the study area. A GIS was used to integrate the geographic information with the hazardous substance database resulting in a tool for use in environmental site assessments, planning for subsequent site characterization, and for environmental educational purposes.
The National Aerial Photography Program As a Digital Ortho Image Map Base for Geographic Information Systems
Authors: Light DL
Published: March 2009

The National Aerial Photography Program (NAPP) is jointly funded by Federal agencies and States that choose to participate in a 50-50 cost sharing cooperative arrangement. The NAPP is designed to acquire black-and-white (B&W) or color infrared (CIR) photography at a scale of 1:40 000. The status of NAPP flying, now going into the first year of its second 5-year cycle, is reviewed to inform the user community of NAPP's coverage. The resolution, geometric quality and flight parameters are used to estimate the system's cartographic potential to produce orthophotoquads, digital elevation models, topographic maps and digital information to meet national map accuracy standards at 1:12 000 and 1:24 000-scale. Also, a technique is presented to compute the optimum scanning spot size (15 µm) and storage required for converting the B&W or CIR photography to digital, machine-readable pixel form. The resulting digital NAPP data are ideally suited as input to geographic information systems engaged in site characterization, resource management, and other mapping related activities.
Design and Testing of Composite Flywheel Rotors
Authors: Gabrys CW , Bakis CE
Published: March 2009

A complete method of designing high-performance composite flywheel rotors is presented in this paper. One rotor design consists of multiple concentric rings of filament-wound, epoxy-matrix composites either press fitted or separated by compliant elastomeric interlayers. The other design involves a novel, thick filament-wound elastomer matrix composite. The elastomer matrix composite offers the potential dual benefits of manufacturing simplicity and fail-safe operation. A summary of design equations, predicted stress distributions during operation, and preliminary test data are presented. Energy densities measured in spin tests and predicted for future burst tests compare favorably with published results of other investigators.
Mode I, Mode II, and Mixed Mode Interlaminar Fracture of Woven Fabric Carbon/Epoxy
Authors: Alif N , Carlsson LA , Gillespie JW
Published: March 2009

Interlaminar fracture behavior of a five-harness satin orthogonal woven fabric carbon/epoxy composite laminate loaded in Mode I, Mode II, and mixed mode has been investigated. Fracture testing employed the DCB, ENF, and MMB specimens. Special emphasis was put on microscopic details of crack growth and their relation to fracture resistance. For all fracture mode combinations it was found that crack growth occurred in a nonplanar region of topology determined by the weave pattern and relative positioning of the plies adjacent to the crack plane. The woven fabric structure constrains fiber bridging, but partial debonding of transversely oriented fiber bundles led to occasional crack branching, stick-slip behavior leading to variations in the Mode I fracture resistance. Slow stable crack growth occurred in the ENF and MMB specimens prior to unstable fracture and resulted in nonlinear load-displacement response. A linear relation between the critical values of GI and GII was observed.
Accuracy Assessment of the Singular-Field-Based Mode-Mix Decomposition Procedure for the Prediction of Delamination
Authors: Davidson BD , Fariello PL , Hudson RC , Sundararaman V
Published: March 2009

The singular-field-based mode-mix decomposition procedure is assessed for its ability to accurately predict delamination growth in various test geometries. Initially, toughness versus mode mix is obtained from laminates with delaminations at their midplanes. These results are then used to predict delamination growth in other geometries, and the associated tests of these geometries are performed. A typical graphite/epoxy material system is considered. For this material, it is shown that predictions of delamination growth using a singular-field-based mode-mix decomposition will result in significant errors. That is, when a classical, singular-field-based definition of mode mix is used, tests of different specimen geometries predicted to be at the same mode mix do not display the same toughness. All the test data is then reinterpreted with the aid of a previously developed crack-tip-element analysis. This approach allows for various definitions of mode mix to be evaluated, of which the singular-field-based result is one special case. It is shown that defining mode mix in terms of non-classical parameters results in accurate predictions of delamination growth, and test geometries predicted to be at the same mode mix now display the same toughness. This new definition of mode mix is based on parameters that uniquely characterize the conditions at the crack tip, but which are insensitive to the scale of the near-tip damage. A systematic method for determining the “appropriate definition” of mode mix for arbitrary material systems is described.
Compression Buckling Behavior of Laminated Composite Panels
Authors: Parida BK , Prakash RV , Ghosal AK , Mangalgiri PD , Vijayaraju K
Published: March 2009

Experimental simulation of boundary conditions while carrying out a panel buckling test has been known to be difficult. In this paper, compression buckling tests on 6.0-mm-thick carbon fiber composite (CFC) panels have been described for which a reasonably good simulation of the boundary condition was achieved, especially under the simple supported condition. Carefully designed test fixtures that provided excellent alignment of the panel with the loading axis and adequate lateral stiffness for edge supports during buckling of the CFC panels were used to achieve this goal. Both simply supported and clamped boundary conditions have been studied. Tests in room-temperature-as-received (RT/AR) and hot-wet (H/W) conditions are described. A buckling test on a simply supported panel with prior moisture conditioning was performed under the H/W condition with an environmental test chamber mounted on the test rig to prevent any loss of moisture during the test at 100°C and ⩾85% relative humidity. Based on these results, a test procedure was developed to identify buckling loads through measurement of out-of-plane displacements rather than relying solely upon longitudinal strain measurement. This procedure facilitated estimation of the buckling load of a hygrothermally aged and simply supported CFC panel under the H/W condition, where accurate strain measurements were found to be rather difficult and at times unreliable. Experimental results were compared with those obtained from finite element analysis with regard to the buckling loads and corresponding mode shapes for the boundary conditions considered. The effect of rounding off the knife edges used for the simply supported condition was specifically studied during FEM analysis and was found to be significant.
An Evaluation of Two Fabrication Methods for Hybrid Titanium Composite Laminates
Authors: Li E , Johnson WS , Lowthere SE , St. Clair TL
Published: March 2009

Hybrid composite laminates consisting of layers of metal alloy bonded together with fiber-reinforced resin show great promise as a high-fatigue-resistant material. Fiber-reinforced metal laminates have been shown to exhibit improved toughness as well as higher resistance to fatigue. The hybrid titanium composite laminate (HTCL) incorporates the mechanical advantages of existing hybrid composite laminates such as ARALL and GLARE while extending its applications for use at elevated temperatures. Fabrication of hybrid laminates involves a consolidation process at appropriate applied pressures and temperatures. Two current methods of consolidation are the hot press process and the autoclave process. This study will compare the mechanical performance of HTCL specimens fabricated by the hot press process with those specimens fabricated by the autoclave. Two titanium metastable β-alloys, Ti-15-3 and Timetal-21S, will be investigated using a high-temperature resin reinforced by carbon fibers. Experimental testing will include composite laminate testing as well as constituent material testing. The mechanical response of autoclaved and hot-pressed HTCL laminates will be compared with predicted response based upon constituent property input utilizing a computer program called AGLPLY.
Modification of the Three-Rail Shear Test for Composite Materials Under Static and Fatigue Loading
Authors: Lessard LB , Eilers OP , Shokrieh MM
Published: March 2009

The main goal of this research was to improve the three-rail shear test for studying the in-plane shear behavior of composite materials in static and fatigue loading. This method is currently a standard guide in the ASTM Book of Standards. Presently over 30 test methods exist that are briefly reviewed. The three-rail shear test was chosen for its ability to produce both strength and modulus values in both static and fatigue testing, as well as for producing a large uniform region of pure shear away from the free edges. The disadvantages of this test method include free edge effects, which cause stresses to differ from pure shear in that area, and premature failure of the specimen initiating at the rail edges. Thus this testing method was improved to eliminate these problems.

In order to fully examine the three-rail shear test method as prescribed in the ASTM Standard Guide for Testing In-Plane Shear Properties of Composite Laminates (D 4255), both the fixture and specimen were examined. Recently, the authors improved the three-rail specimen by performing analytical and experimental studies of the specimen [1]. The analytical results were verified by the three-rail shear test for both the standard un-notched and the new notched specimens. In this research, the fixture itself was examined experimentally and found to be inadequate for fatigue loading. The fixture was thus modified for overall strength and a bottom grip was added for fatigue loading. To eliminate out-of-plane motion of the middle rail, the fixture was again modified to be restrained at the top and bottom while preventing fretting during fatigue testing by using an Oilite bronze lining at the contact surfaces. Thus a new modified fixture was designed to consolidate all necessary modifications, making the fixture suitable for static and fatigue loading. The test results from the fixture show great improvement in both static strength and fatigue life.
A Coulomb-Mohr Type Criterion for Matrix Mode Failure in a Lamina
Authors: Chatterjee SN
Published: March 2009

Failure of laminated composites under in-plane and/or through the thickness stresses is a complex phenomenon. Ply failure is often predicted based on the maximum value (or values) of one or more functionals, such as the maximum stress (strain) or polynomials involving the stress components. Some researchers have pointed out that it is necessary to distinguish between two types of failure, namely, (1) fiber-dominated mechanisms (tension or compression in the fiber direction), and (2) matrix mode failures. Failures in the second mode are expected to occur on planes parallel to fibers, and they can be predicted by seeking a plane on which a functional involving the normal and two shear stress components acting on the plane attain a maximum value. Two such functionals are chosen, one for tensile and the other for compressive matrix failure, and they involve three matrix-dominated strengths, namely, the transverse tensile and shear strengths and the longitudinal shear strength of the ply.

In this work, it is shown that a Coulomb-Mohr type criterion or a combination of such pyramidal failure surfaces, which is physically appealing and is widely used for many brittle materials, such as rock and concrete, can be utilized for predicting matrix mode compressive failures in a lamina. A simple modification is introduced to account for the fact that the transverse shear strength of a ply may be different from its longitudinal shear strength. Predictions are compared with results from other failure theories as well as test data from tension and compression tests on angle ply (± θ)ns and off-axis unidirectional coupons reported in literature. For tensile failure, the criterion has to be modified by introduction of tension cutoffs, which are usually needed for all brittle materials. Use of the criterion under more complex conditions, such as thick composites under three-dimensional stress states is explored and advantages and disadvantages of the criterion are discussed.
Basic Principles Used in the Development of a New Cut-Test Machine for Standardization
Authors: Massé S , Lara J , Sirard C , Daigle R
Published: March 2009

A new cut-test apparatus for standardization has been developed. The apparatus is based on a previously developed cut-test method that consists of sliding a blade on a material and determining the distance traveled by the blade to cut through the material when a constant force is applied. To build a machine for standardization, several requirements were considered. One of the most important requirements was that the force applied at the blade/material point of contact must be constant throughout the test. Other requirements were that the test apparatus be easy to use by an untrained person, that the applied force should be known, and that the results should be reproducible. The force is applied at the material/blade point of contact from bottom upwards through a ram-type arm. To satisfy the requirements, a mechanism based on a double Watt system was developed that allows a perfect vertical displacement of the sample and a constant applied force throughout the test with a maximum error of 2×10-2N.
An Automated Dynamic Water Vapor Permeation Test Method
Authors: Gibson PW , Kendrick CE , Rivin D , Charmchi M
Published: March 2009

An automated apparatus to determine the steady-state and transient water vapor permeation behavior of fabrics and semipermeable laminates is described. Typical test results for representative types of fabrics and semipermeable membrane laminates are shown, as well as correlations between this test and two other water vapor permeability test methods. The use of the equipment to obtain dynamic data for transient situations is shown to be useful in observing equilibration behavior, and in characterizing temperature changes associated with vapor sorption phenomena.
Development of a New Cut Test for Protective Gloves Against Machine-Driven Knives
Authors: Turner RH , Smith DM
Published: March 2009

Staff involved in industrial cutting operations are at risk of injury to their hands from mechanically driven reciprocating or rotating knives. Existing test methods and draft test methods were evaluated using a range of the types of materials used in protective gloves. These tests were found to be inadequate in reproducing either the types of cutting mechanisms or the severity of cut found with mechanically driven cloth cutting machines. A test has been developed to more closely simulate these machines. This test has successfully discriminated between materials with high and low performances.
Impact of Computational Methods Used on Pesticide Residue Reported in Cotton, Polyester, and Cotton/Polyester Blend Fabrics
Authors: Shaw A , Lin Y-J
Published: March 2009

This study was conducted to determine the impact computational methods have on the mass of pesticide reported remaining in the fabrics. Each fabric specimen (10 × 10 cm) was marked along 5 × 5 and 8 × 8 cm lines. Pesticide stained with methylene violet dye was applied to the center of the fabrics with and without a water and oil repellent finish. Excess pesticide was removed after 10 min. The contaminated area was traced and calculated by using a) planimeter and b) maximum length and width of contaminated area (Lmax × Wmax). Prior to extraction, all specimens were cut into three pieces along the five and eight cm lines and each piece extracted separately. The amount of pesticide remaining in the fabrics was calculated using three different methods: a) mass per area (μg/cm2), b) mass per volume (μg/mL), and c) residual mass. Calculations for the first method, mass per area, were based on five different measures: a) contaminated area calculated by using planimeter, b) contaminated area calculated by using Lmax × Wmax, c) specimen area using 5 × 5 cm, d) specimen area using 8 × 8 cm, and e) specimen area using 10 × 10 cm. Findings of the study indicate that in unfinished fabrics, the difference in the mass per area measured by planimeter was as much as 2.2 times greater than that measured in 10 × 10 cm specimens. For fabrics with a water and oil repellent finish, differences were even more dramatic: the mass of pesticide per area reported using the planimeter method was up to 55 times higher than that of 8 × 8 cm specimens and 103 times higher than that of 10 × 10 cm specimens. Selection of appropriate computational method is very important to ensure accurate results and conclusion.
History of the Development of the Total Heat Loss Test Method
Authors: Gohlke DJ
Published: March 2009

The NFPA technical committee on Firefighter's Protective Clothing and Equipment desired, as part of its process for revising NFPA 1971 (1991 edition), to incorporate a performance requirement and test method to address the heat stress associated with wearing firefighter's turnout clothing. The heat stress caused by wearing these ensembles has been a well known, well documented and continuing problem.

A task force was formed to develop a test methodology that would be capable of evaluating turnout clothing composites and that would be relatable to the heat stress levels of the respective composites. It would need to be able to discriminate among ensembles, be sensitive in the range of interest, and be sufficiently reproducible from lab to lab to allow a performance requirement to be established that could be verified by independent testing. It was also desired that the results could be easily understood by the fire service.

The task force developed a method based on the guarded sweating hot plate and showed via round robin testing among four labs of four commonly used composites that it could meet all the desired objectives. Unfortunately, the work was not complete in time to include in the revision and was retained as an appendix.

This paper discusses the alternatives available to the committee and task force and the rationale for the development of the method. Some explanatory language was included as a preamble to the method to help put the results in the appropriate context and to help guard against promotional abuse.
A Study of New Thermal Protective Fabrics Based on Glass and Cotton Fibers
Authors: Gu ZY , Song GW , Chen KN , Liu CY , Zhuan XN , Chen HQ , Jiang LT
Published: March 2009

A new kind of composite material was studied that combined glass-fiber fabrics and cotton fabrics into a new protective clothing material which may be used as protective clothing in metal foundry industries, electric welding operation, etc.. In addition to the excellent flame retardance and heat-radiation performance, this composite material possesses good moisture permeability and soft hand. Two lamination techniques were employed: one was flame lamination with Polyurethane (PU) foam and the other was adhesive bonding. Their performance was tested respectively. During the experiment the different glass-fiber fabrics and cotton fabrics were evaluated and their surface pretreatment was carried out in order to obtain good adhesion strength as well as other properties. Some evaluation tests were also carried out in the study, i.e. molten metal splash, heat radiation, moisture permeabillity, etc.. Thus, a new kind of composite protective clothing material with high flame-retardance and heat-radiation resistance was obtained.
How the Requirements of the EN-Standard on Welders' Protective Clothing Meet the Demands of Normal Use
Authors: Mäkinen H , Kanninen H , Nurmi R
Published: March 2009

Welders are exposed to welding gases, heat and UV-radiation. Welding sparks cause injuries and dangerous situations resulting from the ignition of protective clothing. The performance of the protective clothing plays a significant role in the protection against UV-radiation and small splashes of molten metal. The combining of adequate protection and resistance to wear and care has been a challenge for both researchers and manufacturers of protective clothing. The purpose of this study was to investigate welders' own experiences of the risks in their work and the demands they set in normal use on their protective clothing, as well as how well these demands are covered by European standard EN 470-1 for the protective clothing of welders. Flame resistance, durability to washing, tear resistance especially after washing, dimensional change, protection against sparks and molten drops, and flame resistance were the demands most often set on the highest level. Protection in the neck area against UV-radiation and dust, and pockets with closeable flaps were the most often presented demands on the design. The materials in suits perform well when new, but after use and washing the protection level is lowered considerably. The results of this study demonstrate that char formation improves the protection of materials against small splashes of molten metal. However, during the washing process, the char came off, leaving holes in the material, thus decreasing the protection considerably. Washing five times before flammability and welding tests was not found to be sufficient pretreatment. The pretreatment should also include exposure to welding sparks to some extent.
A Scandinavian Perspective on Human Factors Testing of Personal Protective Devices
Authors: Abeysekera JDA , Xiaoxiong L
Published: March 2009

Whether the two demands such as protection performance and human factors are satisfied in personal protective devices (ppd) can be tested using standardized methodology. The standard methods for performance testing are used for certification of ppd. But it is unfortunate that testing methods for human factors or wearability testing of ppd are scarce and even the methods that have been developed are not always refined nor standardized. Both in hot and in cold environments thermal comfort is an important user need of ppd. To test the thermal characteristics of ppd, methods providing objective data are available but they are not always standardized. However for insulation testing of clothing, standard methods have been developed. The fit of ppd is also a priority need among wearers. Fit of clothing is often tested subjectively. The objective methods developed to test the fit of ppd and clothing require refinement and standardization. It is urgently needed to develop and standardize both objective and subjective testing methods of wearability of ppd. This paper provides insights into some testing methods on human factors of ppd that have found particularly useful over the years.
A Comparison of Techniques Used to Assess the Thermal Burden of Protective Clothing
Authors: Williams JT
Published: March 2009

The majority of test methods available to assess the thermal burden imposed by protective clothing on a subject are used in isolation with little in the way of correlation between them reported. This paper directly compares some of the data obtained on a limited number of protective clothing systems from a range of tests including the Control Dish, Togmeter, two variants of the Skin Model, both Sweating and Thermal Manikins and, most importantly, human subjects. Correlations drawn between the methods show that even the simplest methods give a means of assessing the potential physiological burden of a protective clothing system worn under selected environmental conditions and work rates. The actual temperature profiles of subjects are compared to those predicted by a mathematical model using laboratory data and are shown to be in good agreement.
Twenty Years' Development of ASTM Skiing Standards
Authors: Bahniuk E
Published: March 2009

In 1972 the ASTM F8 Committee on Sports Equipment formed a task group to determine if a subcommittee on skiing standards should be formed. This group first met at Case Western Reserve University in April 1972. The task group evolved into Subcommittee F8.14 of ASTM F8. In 1982, ASTM Committee F27 on Skiing Safety was formed from F8.14. Since 1972 these ASTM committees have written 18 ASTM standards and participated in the development of standards written by the International Standards Committees (TC 83/SC3 and SC4). This paper presents the history and notes some of the people who were involved in these committees.
Gender-Related Injury Patterns in Skiing
Authors: Shealy JE , Ettlinger CF
Published: March 2009

In a two-year nationwide study of 16 ski areas in the United States, using Ski Patrol Incidence reports, a total of 23 011 verified accidents during 8.58 million skier visits were reported. A control group of skiers was randomly selected (n = 2573) to determine the demographic characteristics of the population at risk.

The study shows that differences in the injury pattern (part of body, and nature of injury) between males and females are as dramatic within a given snow skiing activity (alpine versus snowboard) as are the differences between the two snow skiing activities themselves. The overall rates of injuries per thousand skier visits are not significantly different between males and females when assessed for ability, yet the patterns are very different. For example, in snowboard skiing, the female wrist and knee injury rate is about twice that for males, the male face and head injury rate is three times that for females, and the male ankle rate is almost twice that of females. In snowboard skiing, the male fracture rate is higher and the male strain/sprain rate is lower than for females. In alpine skiing, the female knee injury rate is twice that of males.
Death in Downhill Skiing from 1976 Through 1992—A Retrospective View
Authors: Shealy JE , Thomas T
Published: March 2009

This study indicates that death in downhill skiing is disproportionately dominated by males (83% males versus only 63% males in the population at risk). Fatally injured skiers are older than the general skiing public, who in turn are older than the typically injured skier. The typical fatal accident scenario involves an experienced male running into a tree off the edge of an intermediate skill level slope at a high rate of speed, resulting in massive head or neck injury, or both, leading to death. The demographic (age and gender) pattern of fatally injured skiers is very similar to automobile and occupational trauma related death. The rate of fatal injury to downhill skiers is 0.55 deaths per million skier visits, and has not significantly changed over the past ten ski seasons. When the death rate is expressed in terms of fatalities per million hours of exposure, skiing is about seven times safer than travel by automobile or commercial aircraft.
Epidemiology of Facial Injuries Sustained in Alpine Skiing
Authors: Gassner R , Traugott D , Röthler G , Waldhart E
Published: March 2009

Retrospective studies of alpine skiing injuries show a large shift from the lower part of the body to the upper part; thus injuries to the face have become more frequent. In the years 1991 and 1992, out of 1656 injured patients at the Department of Oral and Maxillofacial Surgery of Innsbruck, 179 were skiers.

Of all skiers, 76.5% were between 10 and 40 years of age. Seventy-one patients suffered dentoalveolar trauma (fractures, dislocations, and loss of teeth and periodont). The most exposed bone sustaining a fracture while skiing is the cheekbone. More than half of all accidents were collisions either with other persons or with some obstacle. Of all accidents, 6% took place on lift tracks or at the exit. Of the injured skiers, 24.6% had concomitant injuries, among whom 75% suffered brain injuries.
Muscle Contraction Protects Against Lower Leg Fracture
Authors: Ekeland A , Nordsletten L
Published: March 2009

The contribution of muscle contraction to the loading capacity of the lower leg was studied in young and adult rats.

The lower legs of the rats were fractured in a three-point cantilever bending test during electrically induced muscle contraction. The contralateral tibiae were tested after dissection and served as controls. The ultimate bending moment increased by 73% and 84% in young and adult rats, respectively, during muscle contraction whereas the ultimate energy absorption increased by 149% and 302%.

This experimental fracture is similar to the boot top fracture in skiers. Since the ultimate increase in energy absorption during muscle contraction was half as large in young as it was in adult rats, children correspondingly may have less capacity to absorb energy in the lower leg compared with adults during muscle contraction. This may offer an additional explanation as to why children experience incidence of tibial fractures six to nine times greater than adults during alpine skiing.
Comparison of Spectral Analysis with Fast Fourier Transform and Maximum Entropy Method. Application to the Role of Molybdenum Implantation on Localized Corrosion of Type 304 Stainless Steel
Authors: Beaunier L , Frydman J , Gabrielli C , Huet F , Keddam M
Published: March 2009

A comparison of a spectral analysis using the fast Fourier transform (FFT) and the maximum entropy method (MEM) was carried out in the case in which both methods can be performed, that is, when several time acquisitions can be recorded. A summary of the principles of the MEM is given. Then the main properties of this method are investigated, that is, influence of the MEM order on the spectrum accuracy, validity of the low-frequency plateau usually given by this technique, overlapping of spectra measured for different frequency bandwidths, and influence of a slow evolution of the amplitude of the signal fluctuations.

The susceptibility to pitting corrosion of type 304 stainless steel and type 304 modified by molybdenum (Mo) by means of ion implantation was studied. The power spectral densities (PSD) measured with the FFT and MEM techniques are in reasonable agreement, except for low electrochemical current noises (ECN) buried in the parasitic noise generated by the power supply. In that case, the FFT technique is more appropriate than the MEM, which gave qualitative results only. The type 304 stainless steel showed a large metastable pitting leading to only a few macroscopic pits, whereas the type 304 Mo-implanted specimen showed a very low metastable pitting leading to many hemispheric pits covered by the Mo-implanted layer, under which localized corrosion occurred.
The Identification of Pitting and Crevice Corrosion Spectra in Electrochemical Noise Using an Artificial Neural Network
Authors: Barton TF , Tuck DL , Wells DB
Published: March 2009

An artificial neural network has been developed to identify the onset and classify the type of localized corrosion from electrochemical noise spectra. The multilayer feedforward (MLF) network was trained by classical back-propagation to identify corrosion from the characteristics of the initial current ramp. Using 50 training files and 39 test files taken from measurements on Type 304 stainless steel in a dilute chloride electrolyte, the network accurately detected and classified 96% of the data and reported no misclassifications. Experiments with high levels of adventitious noise superimposed on the original data have been carried out to examine the noise tolerance of the network.
A Progress Report on the Use of Electrochemical Noise to Investigate the Effects of Zebra Mussel Attachment on the Corrosion Resistance of AISI Type 304 Stainless Steel and Carbon Steel in Lake Water
Authors: Brennenstuhl AM , Sim B , Claudi R
Published: March 2009

The electrochemical noise technique was used to determine the effect of zebra mussel settlement on the corrosion performance of AISI Type 304 stainless steel and carbon steel (ASTM A53 Grade B). These materials represent alloys commonly used for handling untreated Great Lakes water at Ontario Hydro's power generating plants. This work was motivated by a concern that zebra mussel settlement will lead to accelerated attack of these materials as a result of the establishment of stable crevice conditions and the growth of corrosion influencing anaerobic sulfate-reducing bacteria (SRB). Corrosion monitoring was carried out in a field test facility that uses the same untreated Lake Erie water as Ontario Hydro's Nanticoke Thermal Generating Station. The test program extended from May through December 1993. During this period, a number of electrochemical parameters were monitored simultaneously, including coupling current, electrochemical potential noise (EPN), electrochemical current noise (ECN), degree of localization (DoL), and resistance noise (Rn). Differences were observed in the performance of the control samples and the samples to which mussels were attached. The results for the AISI Type 304 stainless steel suggested that over the period monitored, mussel attachment reduced corrosion activity. Similarly, signals from carbon steel, samples exposed to mussels, although initially displaying relatively high corrosion rates, exhibited less corrosion damage than did control samples over the longer term. The reason for this difference in performance is not known but is considered to have resulted from a change in the surface environment as a result of mussel attachment, which appeared to diminish corrosion. One possible explanation may be the generation of inhibitive species by the mussels.
The Use of Electrochemical Noise Measurements with Nuclear Waste Tanks
Authors: Mickalonis JI , Jacko RJ , Quirk GP , Eden DA
Published: March 2009

Processing of nuclear materials for either military or civilian purposes generates waste products. The nuclear wastes are generally stored in plain carbon or stainless steel underground tanks. Corrosive wastes are inhibited to minimize the corrosion of these tanks and maintain tank structural integrity under normal and off-normal conditions. Storage tanks have fairly static conditions, although processing of the waste in these tanks to more stable forms will produce dynamic conditions, which may lead to localized corrosion. Corrosion monitoring under either condition, therefore, would ensure that inhibitive conditions are maintained.

A preliminary investigation was conducted to evaluate electrochemical noise measurements for corrosion monitoring of waste tanks. The initial results indicated that current and potential noise correlate to the solution corrosivity. Further development is necessary to differentiate among the various forms of corrosion.

Electrochemical noise measurements were made in the laboratory with plain carbon steel electrodes under simulated conditions for storage and processing of nuclear waste. Coupons were also exposed in the laboratory test vessels. The primary aggressive species of the waste was the nitrate anion, which induces pitting. The simulated waste was initially inhibited with sodium nitrite and sodium hydroxide. The nitrate concentration was increased over the test period to increase the corrosivity of the solution. The temperature was held constant at 40°C.

The current and potential noise showed an increasing trend with nitrate concentrations. Under inhibited storage conditions, the noise data were fairly stable. Inspection of the electrodes revealed little general corrosion with minimal pitting. The coupons, however, had a significant amount of pitting. This difference was attributed to the microstructure of the electrodes and coupons.
On-Line Monitoring Using Electrochemical Noise Measurement in CO-CO2-H2O Systems
Authors: DeBruyn HJ , Lawson K , Heaver EE
Published: March 2009

The stress corrosion cracking (SCC) susceptibility of carbon steel extends over a narrow range of potentials in environments that contain a mixture of wet carbon monoxide-carbon dioxide (CO-CO2) gas. Normal fluctuations in plant operation may cause movement in and out of this range of potentials. Stress corrosion cracking in this case is discontinuous, and an opportunity exists to prevent it by process control.

Electrochemical noise measurement, because of its capability for operation in thin film condensate conditions, is an attractive technique for monitoring corrosion in wet CO-CO2 systems. Laboratory tests and plant trials were carried out to determine if electrochemical noise measurement could be used to characterize periods of SCC.
Electrochemical Noise Measurements on Carbon and Stainless Steels in High Subcritical and Supercritical Aqueous Environments
Authors: Macdonald DD , Liu C , Manahan MP
Published: March 2009

The electrochemical noise induced in a pair of corroding carbon steel probes in simulated heat transport circuit fluids of a supercritical fossil-fueled power plant at temperatures up to 550°C and at pressures as high as 276 bar (4000 psi) was measured as a function of oxygen concentration, flow rate, temperature, and pressure. Additionally, electrochemical noise measurement (ENM) was explored as a means of detecting and monitoring stress corrosion cracking in sensitized Type 304 SS in high-temperature water (up to 288°C). Experimental results from these studies indicate that the electrochemical noise induced from corrosion of steels in high-temperature aqueous systems can be measured in a reproducible manner. The magnitude of the electrochemical noise responds sensibly to changes in the chemical and physical properties of the fluid, and the pattern of the electrochemical noise contains information on the nature of the corrosion processes that occur, including general corrosion, pitting attack, and stress corrosion cracking.
The Use of Electrochemical Noise Measurement in the Evaluation of Materials for Steam Generators
Authors: Doherty PE , Psaila-Dombrowski MJ , Harper SL , Schneider WG
Published: March 2009

In the past ten years, there has been a progressive development in corrosion monitoring technology [1–12]. Initial approaches to evaluate the performance of steam generator (SG) alloys were based on mass-loss coupons and polarization resistance measurements of probes in SG environments or aggressive water chemistries. Corrosion rates and mechanisms were characterized and quantified with data obtained from metallurgical examination of test specimens. Several of these earlier autoclave tests were conducted over a number of years with inconclusive results. Recent interest has focused on the application of modern electrochemical techniques [6,7], such as current and potential electrochemical noise, for greater sensitivity in the evaluation of localized and general corrosion behavior.

This paper reviews the progress to date of a multidisciplinary study to investigate the feasibility of electrochemical techniques to evaluate steam generator materials. The primary techniques investigated were electrochemical current noise measurement (ECNM), zero resistance ammetry (ZRA), and electrochemical potential noise measurement (EPNM). Several applications, including monitoring localized and general corrosion of steam generator tubes and other material combinations, with and without crevices, are discussed. Future developments and their potential impact on plant reliability, integrity, and safety programs are reviewed.
ASTM Standardization of Electrochemical Noise Measurement
Authors: Kearns JR , Eden DA , Yaffe MR , Fahey JV , Reichert DL , Silverman DC
Published: March 2009

The increased utilization of electrochemical noise measurement in corrosion research and industrial process monitoring prompted the formation in 1991 of an ASTM Task Group within the G1 Corrosion of Metals Committee. The scope of the task group was to “develop standards that describe instruments and methods for making and analyzing electrochemical noise measurements.” Task group activities are focused exclusively on measurements to be made in the laboratory. The initial goal has been to develop consensus on: (a) terminology, (b) specifications and configurations for laboratory instrumentation, (c) laboratory apparatus, and (d) data analysis methods. A round robin was also organized to develop a body of data on different material/environment systems using a variety of instrument configurations and data analysis techniques. A guide for making valid electrochemical noise results is being prepared based on the round robin results. The status of the effort to address these and other standardization issues within the ASTM G1.11.04 Task Group on Electrochemical Noise Measurement will be presented.
ASTM Cross-Comparison Exercise on Determination of Material Properties Through Miniature Sample Testing
Authors: Rosinski ST , Corwin WR
Published: March 2009

An international testing exercise was conducted under ASTM Committee E10.02 to obtain a cross-comparison of material properties obtained from various types of subsize-specimen testing techniques. Sixteen organizations representing 10 countries initially participated in the exercise. Objectives were to (1) benchmark various subsize specimen testing techniques by comparing testing results with established material properties for the material tested, and (2) provide information to participants to improve the correlation of subsize specimen testing results with material properties determined through standard ASTM methods. The testing material for the cross-comparison exercise was the ASTM A533 grade B class 1 plate designated as HSST plate 03 provided by Oak Ridge National Laboratory. A variety of miniature testing techniques were utilized by the participants during this exercise. A summary of the exercise and a general comparison of the results obtained are provided. Detailed discussions on individual participant testing programs will be presented by each organization later in subsequent papers.
Sub-Size Impact Testing: CISE Experience and the Activity of the ESIS TC5 Sub-Committee
Authors: Lucon E
Published: March 2009

A suitable test technique and experimental procedure have been developed in CISE for instrumented impact testing of sub-sized Charpy specimens, both V-notched and fatigue precracked, on a 40 J small-scale drop-weight machine. The test technique will be described, including unusual test features, such as in situ temperature conditioning. The results of a series of tests performed on sub-size Charpy specimens will be presented, allowing the influence of various test parameters to be evaluated. Comparisons with standard, full-size specimen data will be presented and discussed as well. Finally, the activity of a Working Group on Instrumented Impact Testing of Miniaturized Charpy V-notch Specimens, active within ESIS Technical Committee 5 and chaired by the author, will be briefly described.
Comparison of Results of Instrumented Charpy- and Mini-Charpy Tests with Different RPV-Steels
Authors: Böhme W , Schmitt W
Published: March 2009

Current activities to standardize the instrumented Charpy test (proposed procedure recently accepted by ISO) and to propose a standardized procedure for instrumented subsized Charpy tests are the background of several round robin exercises of ASTM, ESIS and DVM. The IWM-results are presented here in a comparative manner, together with results of a similar reactor pressure vessel steel under investigation at IWM. Relations between results of full-size and subsized specimens for standardized data, like absorbed energies or transition temperatures, are discussed. Sufficient accuracy and reproducibility of the force-measurements were observed. Different possibilities to evaluate the percentage of shear fracture or to obtain dynamic crack resistance data are also demonstrated. Accuracy and limitations of these advanced evaluations are discussed.
Fracture Toughness Evaluation From Instrumented Sub-Size Charpy-Type Tests
Authors: Schindler HJ , Veidt M
Published: March 2009

The possibilities to derive fracture toughness from small specimens are naturally limited due to constraint requirements which are especially restrictive in toughness testing. In this paper two possible ways are explored theoretically and experimentally to use instrumented sub-size Charpy tests to evaluate fracture toughness related data that are essentially size independent (and can be compared with the ones obtained from larger specimens, e.g. standard Charpy specimens). The first way is to adapt a J-R-curve estimation procedure for analyzing instrumented Charpy tests that has proven to deliver conservative fracture toughness data. The second is to scale-up the characteristic values of the instrumented sub-size tests, which are determined to be the total fracture energy and the energy consumed up to maximum load, and then use the evaluation procedure for standard Charpy specimens mentioned above. The corresponding scaling laws are derived analytically, using simplified mechanical models. The results are compared with experimental data obtained from different specimen sizes.