bluuebunny/crossref_metadata_2025 huggingface dataset:
Flexibility of the Human Knee as a Result of Varus/Valgus and Axial Moments in Vivo: Experiments and Results
Authors: Mills OS , Hull ML
Published: March 2009

Knee ligamentous injuries persist in the sport of Alpine skiing. To better understand the load mechanisms that lead to injury, pure varus/valgus and pure axial moments were applied both singly and in combination to the right knees of six human test subjects. The corresponding relative knee rotations in three degrees of freedom were measured. Knee flexion angles for each test subject were 15 and 60° for the individual moments and 60° for the combination moments. For both knee flexion angles, hip flexion angle was 0°. Leg muscles were quiescent and axial force was minimal during all tests. Tables of data include sample statistics for each of four flexibility parameters in each loading direction.

Data were analyzed statistically to test for significant differences in flexibility parameters between the test conditions. In flexing the knee from 15 to 60°, the resulting knee rotations under single moments depended on flexion angle with varus, valgus, and internal rotations increasing significantly. Also, rotations were different depending on load direction; varus rotation was significantly different and greater than valgus rotation at both flexion angles. Also external rotation was significantly different and greater than internal at 15° flexion but not 60° flexion. Coupled rotations under single moments were also observed. Applying pure varus/valgus moments resulted in coupled external/internal rotations that were inconsistent and hence not significant. Applying pure axial moments resulted in consistent and hence significant varus/valgus rotations; an external axial moment induced varus rotation and an internal axial moment induced valgus rotation. For combination moments, varus/valgus rotations decreased significantly from those rotations at similar load levels in the single moment studies. Also, a varus moment significantly increased external rotation and a valgus moment significantly decreased internal rotation. These differences indicate significant interaction between corresponding load combinations. These results suggest that load interaction is a potentially important phenomenon in knee injury mechanics.
Friction in Machine Design
Authors: Budinski KG
Published: March 2009

This paper reviews available friction model information and the practical equations that apply to determination of friction force. These models are critiqued and recommendations are made on how to treat friction data inquiries. Guidelines are presented on use of available models, friction testing, and friction databases for metal and non-metal couples. Friction models are currently inadequate in their ability to supply “hard numbers,” for real sliding systems; for the present the designer must rely on estimates or testing.
Materials and Substance Data Banks in COMECON Countries and in the USSR
Authors: Kozlov A
Published: March 2009

The paper reviews the work on materials and substance standard reference data (SRD) since 1972 when it was decided by the COMECON Commission to establish a Working Group with that purpose. The most active participants of the SRD system are Bulgaria, Hungary, GDR, Poland, USSR, and Czechoslovakia. In 1984, ministers of five countries signed an agreement for the development of the COMECON SRD system. The structure and the major results of the activities of the SRD are presented. Major results presented are in the areas of the data bank certification procedures and standardized reporting of data. An extensive report on materials data banks in the Soviet Union is also given.
The Benefits and Economic Consequences of Materials Property Databases
Authors: Barrett AJ
Published: March 2009

Computerized materials property databases and networks are at the leading edge of the introduction of machine readable, numeric data systems in technology. Managers of such systems are faced with pioneering the acceptance both of a new product, namely, high quality data, and a novel means for its delivery. They are well able to catalog the features of their systems, but some of them are less articulate on the benefits which are on offer and which need to be put forward to funding bodies and to potential users.

A CODATA project is currently drawing up structured lists of benefits classified under functional headings. This is a first step in constructing a practical package of assistance to materials database managers in the promotion of their systems, in the evaluation of actual user needs, and, eventually, in preparing a basis for the realistic demonstration of favorable national and international economic consequences.
Standards for Materials Databases: ASTM Committee E49
Authors: Rumble J
Published: March 2009

To prevent duplication of effort and to facilitate the building of compatible databases on material property data, ASTM Committee E49 on Computerization of Material Property Data has active efforts underway to develop standards and guidelines in the areas of: (1) designation systems for engineering materials, (2) recording formats for test results and other property data, (3) formats for the exchange of data between materials databases and for data entry purposes, (4) indicators of data quality, and (5) harmonized terminology. A wide variety of draft documents in each area is moving through the standards process, and these will be described in some detail. Several aspects deserve greater discussion. First, the concept of a universal numbering system for ceramic, polymeric, and composite materials is presently being considered. This system would be developed as a cooperative effort between Committee E49 and other industry groups. Second, the proliferation of formats for test results strains attempts to keep the formats as uniform and as compatible as desired. To avoid problems, Committee E49 is developing generic guidelines and their features are discussed. Finally, materials data exchange formats being developed for commercial transactions and product definition do not cover the needs of the materials database community. Again, the ASTM Committee E49 approach is addressed.
Fatigue Data Pooling and Probabilistic Design
Authors: Yu MT , Lu FJ , Topper TH , Irving P
Published: March 2009

In this paper, the authors propose data pooling techniques that allow designers to extract statistical measures of fatigue resistance and its variability from several sets of fatigue data for a given material. As the number of fatigue data banks and the exchanges of fatigue data continue to increase, these techniques will enable designers to obtain fatigue statistics from pooling of data sets that could not be obtained from any one of the invariably small sets of data. When stress-life fatigue data are plotted on log-log scales, the Basquin relationship, a simple inclined straight line, is used to fit the data. When strain-life fatigue data are plotted on log-log scales, two inclined lines are used to fit the data. Elastic and plastic strain fatigue data are plotted based on Basquin and Coffin-Manson relationships, respectively. Fatigue data sets from the same population are pooled together based on the variance, slope, and intercept of the samples. Applications of the data fitting and pooling are presented using sample data sets. A probabilistic design concept is illustrated using pooled material data and arbitrary load histories.
Materials Property Database Requirements for Gas-Fueled Ceramic Heat Exchangers
Authors: Munro RG , Begley EF
Published: March 2009

The Structural Ceramics Database (SCD) system is being developed at the National Institute of Standards and Technology to provide a critical link between the development of new materials in research laboratories and the application of those materials in industry. To achieve this goal, considerable effort is being devoted to establishing the SCD materials property database in a highly user-friendly computerized format for use on personal computers. The system is designed to provide a consistent and attractive mechanism for communicating critical data to design engineers involved in product development.

The development of the SCD is being guided by focusing attention on specific applications. Such focusing provides a more cost effective approach to database construction because the materials and the properties included in the system are determined and constrained by the needs of the application. The utility of the resulting data, however, extends well beyond the guiding application.

The first phase of the development of the SCD is focused on the material, property, and information requirements that derive from the specific application of a materials property database to ceramic heat exchangers.
Comparison of a Wall Moisture Model with Field Data
Authors: Jhinger HS , Yuill GK , Hamlin T
Published: March 2009

The moisture data measured in several different wall panel configurations at the Atlantic Canada Test Hut Project was analyzed in order to establish a relationship between the panel drying rate and the panel configuration. The permeability of the panel assemblies was found to be a key factor in determining the drying rates of the panels. The panels with higher permeability dried faster than the panels with lower permeability. A dynamic wall moisture simulation computer program, WALLDRY, developed by the Canada Mortgage and Housing Corporation (CMHC) was used to simulate the performance of the panels tested at the Atlantic Canada Hut Project. The results obtained from the WALLDRY simulations were compared with the moisture data measured for the corresponding panel configurations at the test hut project. In about half the panel simulations, WALLDRY adequately predicted the moisture content profiles, however, a number of weaknesses in the model were recognized and modifications to WALLDRY were suggested.
Matrix Cracking in Composite Laminates with Resin-Rich Interlaminar Layers
Authors: Ilcewicz LB , Dost EF , McCool JW , Grande DH
Published: March 2009

The critical stress or strain causing the onset of matrix cracking in composite laminates has been referred to as in situ transverse lamina strength. A majority of past studies have considered relatively brittle composites exposed to room temperature environments and static load conditions. In the current work, fracture mechanics analysis and test data for a toughened composite material that has a resin-rich interlaminar layer (RIL) were used to investigate in situ strength. Exposure to a range of environmental conditions was considered.

A parametric analysis study was performed to judge the effects of laminate and material variables. A finite thickness effect, indicating an interaction between ply group thickness and effective flaw size, was found dominant. The magnitude of the effect was directly related to RIL stiffness. In situ strength was found to decrease with decreasing RIL stiffness. Experiments with five different laminate layups and six different environmental conditions confirmed the analysis. This work indicates the need to use a fracture mechanics model of actual lamina microstructure and heterogeneous properties to predict in situ strength in materials with RIL.
Mixed-Mode Fracture in Fiber-Polymer Composite Laminates
Authors: Hashemi S , Kinloch AJ , Williams G
Published: March 2009

Mode I, Mode II, and Mixed-Mode I/II interlaminar tests on unidirectional carbon-fiber composites have been conducted using beam specimens. Both a thermosetting-based (an epoxy resin) matrix and a thermoplastic-based (poly(ether-ether ketone)) matrix have been employed. The fracture energy, Gc, has been ascertained and the various correction factors that need to be applied if accurate results are to be obtained are described. Where Mixed-Mode I/II loadings may have been present, the measured value of Gc has been partitioned into the separate GI and GII components. The experimental results all suggest that the partitioning of G on a global energy basis, as opposed to using local stress-field solutions, is the most appropriate for the laminates. Thus, the differences in energy absorption are a consequence of opening as opposed to sliding, and the symmetry, or otherwise, of these motions is not important. It is thus apparent that a global energy analysis is entirely satisfactory and appropriate for these types of systems. Finally, it is also shown that when the failure locus is plotted in the form of GI versus GII then it may be theoretically described by a simple interaction parameter model, where the interaction parameter, Ii, has a linear dependence upon the value of GI/G.
Three-Dimensional Stress Analysis of Plain Weave Composites
Authors: Whitcomb JD
Published: March 2009

Techniques were developed and described for performing three-dimensional finite element analysis of plain weave composites. This paper emphasizes aspects of the analysis that are different from analysis of traditional laminated composites, such as the mesh generation and representative unit cells. The analysis was used to study several different variations of plain weaves that illustrate the effects of tow waviness on composite moduli, Poisson's ratios, and internal strain distributions. In-plane moduli decreased almost linearly with increasing tow waviness. The tow waviness was shown to cause large normal and shear strain concentrations in composites subjected to uniaxial load. These strain concentrations may lead to earlier damage initiation than occurs in traditional cross-ply laminates.
Minimum Requirements for Standard Pavement Management Systems
Authors: Hudson SW , Hudson WR , Carmichael RF
Published: March 2009

In 1965 a team of engineers from ARE Inc developed for the National Cooperative Highway Research Program the initial concept of pavement management. Subsequently, the authors have worked on a variety of pavement management applications worldwide at both the project and network level and at the city, county, state, and national level. This paper summarizes a series of findings from these extensive studies and outlines the institutional aspects of pavement management which have been found to be required for standard applications and for minimum success of a pavement management system. While the paper does not present quantitative mathematical relationships for pavement management, it does present standardization concepts and minimum requirements that have proven successful in a number of cases. Specific case studies and examples are also provided as a part of the paper.
Generically Based Data Needs and Priorities for Pavement Management
Authors: Haas R
Published: March 2009

The foundation for pavement management is reliable and sufficient data. It is required to quantify present and future status, to identify needs and to provide the basis for priority programming of maintenance and rehabilitation. The role of data in a generically based pavement management framework is to provide the factual basis for activities models, methods and procedures, and for making decisions, at both the network and project levels. In order to develop a strategy and priorities for what data should be acquired and how often for any particular situation requires consideration of such factors as type and class of facility, characteristics of the agency, intended uses of the data, costs and the accuracy needed. Sets of priority guidelines for highway, airport and other area pavements, using these factors and for average or representative conditions, have been developed.
20 Years Experience in the Paver Pavement Management System: Development and Implementation
Authors: Shahin MY
Published: March 2009

The development of a pavement management system for the US Army began in 1968. Since that time there have been many successes, but the road to development and implementation has been full of obstacles and can generally be described as “rough. This paper discusses the Army's PAVER pavement management system in terms of its history, development challenges, implementation obstacles, and solutions.

The Development issues that proved to be significant included: * Engineering technology as it relates to pavement mechanistic behavior, pavement distress, condition prediction modeling, and optimization. * A sponsor who understands the importance of pavement management and is willing to defend its development. * A user group that is progressive and willing to give constructive direction and feedback. * A research team that is not discouraged by tough challenges or initially disappointing results.

The Implementation issues that proved to be significant included: * Availability of manpower and monetary resources. * The pavement management system's ability to provide for field needs such as annual planning, long-range work planning, and project justification. * Availability of credential training. * Endorsement by nationally respected organizations such as APWA, FAA, and FHWA. * Obtaining system approval by the head organization. * Finding the right branch and the right responsible person within the implementing agency.

This paper discusses all the above issues and includes a description of PAVER'S evolution from 1968 to 1990, from both a development and an implementation point of view.
A Critical Assessment of Pavement Management Standardization
Authors: Clark GN , Moore RK
Published: March 2009

All aspects of implemented pavement management systems (PMS) cannot be standardized. However, several candidate areas for standardization related to pavement performance monitoring appear promising. These include the definitions of roughness, distress severity, and distress extent. Standardization may be useful for specification of equipment capability in measuring pavement roughness and distress. This does not imply that all agencies should use the same distresses as the critical parameters for triggering maintenance or rehabilitation actions. The KsDOT experience has clearly affirmed the necessity that a PMS be adaptable to the way a highway agency does business. A PMS may have specific standard parts or modules, but these must work within the existing agency planning and programming framework. Other generic standardization opportunities include PMS generated “products” (reports and data summaries) and PMS development and implementation steps.
Innovations in PMS — State of Ohio & Kingdom of Saudi Arabia
Authors: Harper WV , Majidzadeh K
Published: March 2009

Two different Pavement Management Systems (PMS) are discussed in this paper. One developed for the Ohio Department of Transportation (ODOT) has deterministic degradation models based on historical data. The ODOT system is optimized using a 0–1 optimization. This is solved using linear programming techniques including generalized upper bounding to considerably improve the computational efficiency. The second PMS discussed is part of a Highway Maintenance Management System developed for the Kingdom of Saudi Arabia that integrates a PMS, a Bridges & Structures Management System, and a Nonpavement Management System. It is a stochastic optimization system using initial prediction models partially based on expert opinion. The Saudi Arabian system is a Markovian based optimization that uses Lagrange methods to link together the various strata within the system. The use of Lagrange methods combined with parametric programming efficiently solves very large problems. An algorithm is presented for updating degradation models for pavements. Bayesian statistical procedures are given that automatically update the degradation models with new survey data. These procedures continually self-adjust the PMS to fit the specific conditions found in the network. This results in improved prediction models and a better utilization of resources.
A Pavement Surface Model for Integrating Automated Management Data
Authors: Haas CTM , McNeil S , Hendrickson CT , Haas RCG
Published: March 2009

Good data on performance, geometry, materials, environment, costs and other factors provides the foundation for pavement management. While some very advanced technologies have been applied to collecting this data, particularly in non-contact sensing and automation, there is unfortunately also a very wide diversity and incompatibility among methods and results. This paper suggests that such diverse data and technologies can in fact be exploited in a standardized way through the use of an integrated surface representation model. An example application of the model is provided in the paper. It uses data from three current acquisition systems. Data from these systems are integrated into the model's standard representation from which common pavement condition indices are derived using the model's tools. The paper also describes additional benefits of the model in pavement management.
New and Old Technology Available for Pavement Management System to Determine Pavement Condition
Authors: Al-Qadi IL , Sebaaly PE , Wambold JC
Published: March 2009

The feasibility of many old and new technologies that can be used in determining pavement condition have been investigated. These technologies include image processing, electromagnetic waves, nuclear, laser, spin-up/spin-down, eddy current, and ultrasonic waves. Various equipment in use and under development in United States and Europe have been identified and evaluated. The following measurements were considered: Crack, skid resistance, texture, profile, rut, deflection, voids detection, moisture, delamination of thin overlays, joint/crack spalling, and joint/crack damage. Some of the top identified equipment were evaluated for use at the network and project levels. The evaluation was based on technical merit. It was concluded that the existing deflection and longitudinal profiling equipment are adequate. In the case of skid resistance, the information obtained from the existing ASTM skid trailer can be greatly improved with the spin-up/spin-down technology. Electromagnetic waves showed promising results in various areas of application. The nuclear technology also showed some promising results in certain application. On the other hand, ultrasonic technology had serious limitations, especially in penetrating the pavement material, while eddy current technology showed no promise at all.
Stabilization Mechanisms in Polyolefin-Asphalt Emulsions
Authors: Hesp SA , Woodhams RT
Published: March 2009

The successful use of polyethylene as a polymeric modifier in asphalt paving materials has encouraged research into development of a product where the polyolefin is emulsified in the hot asphalt medium without being subjected to phase separation. In the last thirty years, patents and publications have given new and old ways of accomplishing the difficult task of achieving an inherently stable mixture.

These polymer-in-asphalt type dispersions suffer from a tendency towards gross phase separation by coalescence and subsequent creaming. It has been reported in a number of feasibility studies that the polymer-asphalt incompatibility, as experienced in polyolefin modified mixtures, translates into a deterioration of ultimate properties. However, in the absence of these detrimental effects, asphalt concrete properties could be enhanced significantly. The possible benefits to our roads as reported in the literature are substantial: increased rutting resistance, low temperature cracking resistance, elevated tensile strength and others.

A condensed review illustrates the various approaches that have been employed for the stabilization of polyolefin dispersions in asphalt binders for paving applications.
Field Trials with Polymer Modified Asphalts in Saudi Arabia
Authors: Dhalaan MA , Balghunaim F , Dhubaib IA , Noureldin AS
Published: March 2009

This paper presents field trials with polymer modified asphalts (Novophalt and Styrelf). The modified binders were used in wearing surface course, binder course and base course and compared with non modified asphalt. Field evaluation included visual survey, roughness measurements and deflection measurements. Preliminary results of these field trials indicated that no significant improvements in pavement performance were obtained. The one year evaluation (after test track construction) under heavy traffic movements did not show significant rut development for either polymer modified or non modified bituminous sections. However, it is planned to annually investigate and report the extent of improvement in pavement performance which might occur in the future when using these polymer modified asphalt binders.
Comparative Performance of Polymer Modified Hot Mix and the Practical Problems of Ensuring Performance
Authors: Heather WPF
Published: March 2009

To realize the benefits in performance that modified asphalts can give to road pavements attention has to be addressed to the practical problems of their handling, storage and usage by contractors. Problems have been identified on some job sites due to varying percentiles of the modifier caused by poor handling at the coating plant. Some rheological properties of the modified asphalts are of lesser utility for assessing performance than tests such as the Dry Wheel Tracking Test. There must be a clear perception by specifiers as to what specific problems they need to be solved so that the right modifier is used in a cost effective way.
Polymer Modified Asphalt Concrete for Environmental Liners
Authors: Terrel RL
Published: March 2009

Conventional liners and covers for solid waste storage are typically constructed of multiple layers of compacted clay and flexible membranes to prevent undesirable leachate from entering the ground water system. An effective alternative is a system of asphalt concrete to provide a strong and durable impermeable liner system with one or more layers. Polymer modification of the asphalt binder provides the ability to increase binder content for impermeability without sacrificing flexibility and strength. The benefits of these materials were demonstrated in the construction of a liner for incinerator bottom ash near Bellingham, Washington.
An Experimental Investigation of the T Stress Approach
Authors: Sumpter JDG
Published: March 2009

Many investigations have identified geometry dependence of Jc at initiation of cleavage fracture and Ji at initiation of fibrous tearing. This geometry dependence is predictable from elastic-plastic finite element analyses, which show that the crack tip stress-strain distribution is not always uniquely defined by J. This paper investigates the ability of the elastic T stress to explain experimentally observed trends in Jc with changes in specimen geometry. Data on mild steel three-point bend and center-cracked tension specimens are presented.
Real-Time Acousto-Ultrasonic NDE Technique to Monitor Damage in SiC/CAS Ceramic Composites Subjected to Dynamic Loads
Authors: Tiwari A , Henneke EG
Published: March 2009

A real-time acousto-ultrasonic (AU) nondestructive evaluation (NDE) technique was developed to study the damage mechanisms of unidirectional and cross-ply SiC/CAS ceramic composites. Real-time AU was found to be very sensitive in detecting the stress levels at which the onset of matrix cracking occurs and the stress level for saturation of matrix cracking. Real-time AU as developed and presented in this paper can continuously monitor damage under cyclic loads and hence enhance our understanding of damage mechanisms in ceramic composites.
Advanced Backcalculation Techniques
Authors: Uzan J
Published: March 2009

The backcalculation procedures are separated into five categories; (a) static linear elastic, (b) static nonlinear elastic, (c) dynamic linear using frequency domain fitting, (d) dynamic linear using time domain fitting and (e) dynamic nonlinear analysis. In this paper each category is described and case studies are presented comparing their results. Advanced techniques require more complete material characterization models. In the nonlinear elastic procedure a universal k1 - k5 model (an extension of the bulk modulus model) is used. In the dynamic analysis technique a generalized power law relationship is used for the asphaltic layer. Two case studies are presented. In the first the nonlinear elastic scheme was found to give excellent results at matching deflection bowls at four different load levels for each of two test sites analyzed. In these analyses only the k1, of the k1 - k5 model was backcalculated. It was found that the backcalculated k1 in all layers including the asphalt concrete are larger than those measured in the laboratory. In the second case study dynamic analysis techniques are applied to full wave shape data obtained from the SHRP data base. Both the frequency and time domain procedures are shown to yield reasonable results.
Extrapolation of C(T) Specimen J-R Curves
Authors: Wilkowski GM , Marschall CW , Landow MP
Published: March 2009

In many structural flaw evaluations, frequently it is necessary to predict the maximum load where a ductile tearing failure mode is expected. In such a calculation, large ductile crack growth needs to be accounted for to predict the maximum load, especially for large structures and/or lower toughness materials. One difficulty in such an evaluation is that the amount of crack growth obtainable in C(T) specimens that can be machined from the material (e.g., from a pipe) is relatively small. Because of this, it is necessary to extrapolate the J-R curves to the larger amount of crack growth. No generally accepted method exists for such extrapolations.

This paper discusses methods used to evaluate J-R curves extrapolation techniques. As part of this study, several materials were evaluated using C(T) specimens of various sizes but with the same thickness. This is frequently the case for piping, whereas for a pressure vessel or other heavy-wall structure the specimens will frequently not even be the same thickness as the structure. The results in this study showed more geometry effects with the JM-R curve than expected.
Dynamic Fracture Behavior of a Structural Steel
Authors: Cho K , Sklenak JP , Duffy J
Published: March 2009

Fracture experiments are described in which stress wave loading is employed to attain a stress intensity rate of about 2 ∙ 106 MPa √m/s. The specimens consisted of prefatigued notched round bars of a high strength, low alloy martensitic steel. The tests covered the temperature range -150°C to 200°C. Comparison is made with corresponding results of quasistatic tests on specimens of the same geometry as well as with results of other investigators who tested similar steels. The present steel contains manganese sulfide inclusions in the form of stringers and globules. Their role in the fracture process is examined by optical and scanning electron microscopy.
Fracture Toughness in the Transition Regime for A533B-1 Steel: The Effect of Specimen Sidegrooving
Authors: Morland E
Published: March 2009

This report describes the results of an experimental test program to investigate the influence of specimen sidegrooving on the cleavage fracture toughness of A533B-1 steel. The work represents a companion study to a previous investigation into the effects of specimen size on the cleavage fracture toughness of the same A533B-1 plate material.

Compact specimens were prepared in two sizes (12.5 and 25 mm thick) in the 0, 20 or 50% sidegrooved conditions. A total of 160 tests were performed in the transition regime with a minimum of 29 specimens being tested for each specimen size and depth of sidegrooving. Variations in cleavage fracture toughness were characterized using exponential curve fits to data across a temperature range and arithmetic mean values calculated at discrete test temperatures.

The results show that sidegrooving has the effect of decreasing the mean level of cleavage toughness in the upper transition regime (high mean K levels) and increasing it in the lower transition regime (low mean K levels). These results are explained in terms of the competing effects of increased specimen constraint and reduced net thickness in sidegrooved specimens. Reduced resistance to ductile tearing in sidegrooved specimens is also shown to be a contributing factor to decreased toughness levels in the upper transition regime.
Prediction of Fracture Toughness by Local Fracture Criterion
Authors: Miyata T , Otsuka A , Mitsubayashi M , Haze T , Aihara S
Published: March 2009

Incorporation of micromechanistic criteria of failure to analytical or numerical crack tip stress and strain solutions, known as the RKR (Ritchie, Knott, and Rice) model, derives a certain relation between the fracture toughness and flow/fracture properties of materials. Based on the above analytical prediction, correlations between the fracture toughness and yield stress, cleavage fracture stress, and critical plastic strain of the materials have been investigated for cleavage and ductile fracture. Nine types of low carbon structural steel were tested that had various microstructures with yield strengths of 280 to 1110 MPa. Good correlations according to analytical predictions have been obtained for both cleavage and ductile fracture, and the possibility of quantitative prediction of the fracture toughness from a conventional round bar tensile test can be shown. Effects of metallurgical and mechanical factors on the fracture toughness, and temperature dependence of the fracture toughness, can be explained from their effects on the flow and fracture properties.
Use of the Direct-Current Electric Potential Method to Monitor Large Amounts of Crack Growth in Highly Ductile Metals
Authors: Marschall CW , Held PR , Landow MP , Mincer PN
Published: March 2009

The direct-current electric potential method is receiving increasing attention for monitoring crack extension in J-resistance curve testing. Among its advantages over the unloading-compliance method are: (1) no time-consuming unloadings are required, (2) a continuous record of crack extension versus displacement can be obtained, and (3) the method can be used at higher strain rates where unloading compliance cannot be used.

Despite the advantages of the direct-current electric potential method, questions persist regarding its ability to monitor large amounts of crack growth in highly ductile materials where large displacements and large amounts of plastic strain occur. This paper presents details of an experiment conducted on a 3T planform-size compact specimen of 25.4 mm thickness to assess the ability of the direct-current electric potential method to accurately measure crack extension in a highly ductile material. The material selected was Type 304 austenitic stainless steel. It was found that the Johnson expression, often used to calculate crack extension from direct-current electric potential data, significantly underestimated the actual amount of crack extension. However, a simple modification of the Johnson expression resulted in excellent agreement between calculated and measured crack extensions.
Keynote Address: Plants—Keystone to Risk Assessment
Authors: Benenati F
Published: March 2009

This keynote speech provides an overview of the plant test data submitted in the past ten years to the U.S. Environmental Protection Agency under the Toxic Substances Control Act (TSCA). Only 155 of 12 403 Premanufacture Notices required for new chemicals contained plant data. Most of these notices (149) contained only algal data. An additional 23 algal assays were required for existing chemicals subject to test rules and testing consent orders. Plant test data from over 400 studies (again mostly algal) were also submitted in response to information gathering rules. The plant data, while less frequently submitted than fish or aquatic invertebrate data, demonstrated that the algal assay is a good tool for screening chemicals for toxicity. However, whether or not this test adequately screens chemicals for phytotoxicity is questioned. The use and limitations of plant data in risk assessment are also discussed along with the need for standardization and validation of plant test methods.
Relationship between Acoustic Emission and Flaw Size in Si3N4 Ceramics
Authors: Mori Y , Kishi T
Published: March 2009

Acoustic emission behavior was investigated in the Si3N4 ceramics in order to study the effect of flaw size on fracture strength. A close relation between the generation of acoustic emission and flaw size was found. It was found that acoustic emission signals can be detected only just before specimen failure with flaw size of 15 μm,1 a critical flaw size estimated for the materials, or larger. Whereas flaws smaller than 15 μm began to generate emissions at the stress level, approximately 50 % of the strength of the specimens failed. In the latter case, it was concluded that emissions were due to microscopic fracture events around inherent flaws.
Acoustic Emission Monitoring and Analysis Procedures Utilized During Deformation Studies on Geologic Materials
Authors: Sun X , Hardy HR , Rao MVMS
Published: March 2009

During a recent detailed study, AE signals generated from rock specimens stressed to failure during uniaxial compressive tests were monitored and recorded on a SONY (AV-3650) videocorder. Various AE parameters, including: amplitude, pulse width, ringdown count, rms level, etc…, were then extracted during videocorder playback. The data acquisition and processing techniques used are discussed in this paper. Amplitude distribution analysis was carried out by dividing the AE events into four categories according to their maximum amplitude. This analysis provides a better appreciation of the overall deformation process.
Fracture Mechanism Studies of a Carbon Fiber-Peek Composite by Acoustic Emission
Authors: Ono K , Jeng JS , Yang JM
Published: March 2009

Failure mechanisms of a thermoplastic matrix composite, a carbon fiber reinforced PEEK (Polyetheretherketone) matrix laminate, were studied. Three-point bending, ENF (end-notched flexure), and tensile tests were used. During each test, load and acoustic emission (AE) parameters were recorded. Several AE para-meters of processed AE events were analyzed to distinguish different fracture modes, such as fiber breakage, delamination, matrix cracking, and splitting (longi-tudinal matrix cracking). The features such as peak amplitude, signal duration and energy distributions of AE events as well as a plot of peak amplitude vs. signal dura-tion were used, but clear discrimination of different mechanisms by AE alone was difficult as the distributions overlapped. In conjunction with other findings, the first two mechanisms show certain features that may be useful in isolating the failure processes.
Suggested Guidelines for the Use of PTFE, PVC and Stainless Steel in Samplers and Well Casings
Authors: Parker LV
Published: March 2009

This paper reviews the literature on PTFE, PVC and stainless steel well casings and samplers and develops a series of suggested guidelines for use of these materials in sampling programs. Three factors are considered: the resistance of these materials to chemical reaction and thus degradation by the environment, the effect these materials have on the integrity of ground water samples, and the physical strength of these materials. Specifically, factors involved in the corrosion of stainless steel and the ability of aqueous solutions of organics to degrade PVC are discussed. Also considered are sorption and leaching of organic and metal species by these materials. The differences in the behavior of flexible vs. rigid PVC are emphasized.
Protective Clothing Development at New Zealand Aluminium Smelters Ltd
Authors: Coughlan JE
Published: March 2009

Historically in the smelting industry, burns which result in serious injuries, with the potential to be fatal are caused from exposure to molten aluminium and molten bath electrolyte splash. Employees clothing is their final line of defence from these hazards.

Results from laboratory and wearer tests showed that a lightweight ZIRPRO treated 100% wool fabric provided excellent protection from molten aluminium (750°C—900°C) and molten bath electrolyte (cryolite 1050°C) yet was lightweight and comfortable to wear, durable, and easy to launder.

NZAS adopted clothing made from this fabric - sitewide as an alternative to traditionally worn borax treated cotton garments.

The effectiveness of the new wool clothing is presently being evaluated along with the impact that this change, which affected all employees has had on the NZAS workforce.
A Plant Bioassay for Assessing Plant Uptake of Contaminants from Freshwater Soils or Dredged Material
Authors: Folsom BL , Price RA
Published: March 2009

The plant bioassay described herein is one of the modules of the decision-making framework developed by the U.S. Army Engineer Waterways Experiment Station for evaluating sediments before dredging. Collection and preparation of sediments are described as well as conduct of the plant bioassay. The bioassay is appropriate for estimating mobility of contaminants into the environment through plant uptake in wetland, marsh environments as well as drier agricultural-type upland conditions.
Photoinduced Toxicity of Polycyclic Aromatic Hydrocarbons to the Higher Plant Lemna Gibba L. G-3
Authors: Huang X-D , Dixon DG , Greenberg BM
Published: March 2009

Polycyclic aromatic hydrocarbons (PAHs) are known to exhibit photoinduced toxicity to animals and microorganisms, especially in the presence of ultraviolet (UV) irradiation. Since higher plants readily assimilate PAHs from the environment, and since they cannot avoid UV radiation (a natural component of solar radiation), PAHs have the potential to be a potent phytotoxicant. We have begun to assess the photoinduced toxicity of two PAHs (anthracene and phenanthrene) to the higher plant Lemna gibba. In the presence of low-intensity visible light (60 μmol m-2 s-1, 400 nm to 700 nm), anthracene and phenanthrene were found to be essentially nontoxic. However, both compounds were highly toxic to Lemna in low levels of simulated solar radiation [visible light, 30 μmol m-2 s-1; UVA (320 nm to 400 nm), 4 μmol m-2 s-1; UVB (280 nm to 320 nm), 0.6 μmol m-2 s-1]. Furthermore, in the absence of plant tissue, anthracene and phenanthrene were chemically modified by simulated solar radiation. These photomodified PAHs exhibited toxicity in visible light and increased toxicity in simulated solar radiation.
Solidification and Stabilization of Phenol and Chlorinated Phenol Contaminated Soils
Authors: Sell NJ , Revall MA , Bentley W , McIntosh TH
Published: March 2009

Phenol and chlorinated phenols are toxic compounds found in many treated wood products such as fence posts and railroad ties, hence soils near such treatment facilities or near old railroad yards can be quite contaminated. This study investigated the results of using sodium bentonite clay modified with dimethyl di(hydrogenated tallow) ammonium chloride mixed with Type I portland cement to immobilize a series of phenols (phenol, 2,4,6-trichlorophenol, and pentachlorophenol) from a sandy Shawano B horizon (typic Udipsamment) soil.

The test soil was mixed with the various phenols at a contaminant concentration of 1000 mg/kg. An admixture of contaminated soil and modified clay (0 to 10% w/w organoclay) was prepared. Final solidification was done by adding cement at concentrations of 16 to 39% w/w. Toxicity characteristic leaching procedure (TCLP) and unconfined compressive strength determinations were made. The results of these tests indicate potential for using these organoclay admixtures for treating soils contaminated with various chlorinated phenols.
Performance Testing of Grout-Based Waste Forms for the Solidification of Anion Exchange Resins
Authors: Morgan IL , Bostick WD
Published: March 2009

The solidification of spent ion exchange resins in a grout matrix as a means of disposing of spent organic resins produced in the nuclear fuel cycle has many advantages in terms of process simplicity and economy, but associated with the process is the potential for water/ cement/resins to interact and degrade the integrity of the solidified waste form. Described in this paper is one possible solution to preserving the integrity of these solidified waste forms: the encapsulation of beaded anion exchange resins in grout formulations containing ground granulated blast furnace slag, Type I-II (mixed) portland cement, and additives (clays, amorphous silica, silica fume, and fly ash). The results of the study reported herein show that the cured waste form tested has a low leach rate for nitrate ion from the resin [and a low leach rate is inferred for Technetium-99 (Tc-99)] and acceptable durability as assessed by the water immersion and freezing/thawing test protocols (but often not as assessed by a wetting/drying test protocol). The results also suggest that a tested surrogate waste form prepared in vinyl ester styrene binder performs satisfactorily against the wetting/drying criterion, and it should offer additional insight into future work on the solidification of spent organic resins.
Leach Studies: Influence of Various Parameters on the Leachability of Cesium from Cemented BWR Evaporator Concentrates
Authors: De Angelis G , Marchetti A , Balzamo S
Published: March 2009

The influence of different parameters on the leaching of cesium from cemented boiling water reactor (BWR) evaporator concentrates (sulfates) was tested. In particular, the variation of the following parameters was evaluated: temperature, initial tracer concentration, renewal and chemical composition of the leachant, and specimen size. In a further series of tests, the following effects on leaching were also taken into account: leachant volume, addition of air-entraining agent to the mix, shorter curing times (3 days instead of 28 days), different ways of carrying out the test (static, instead of dynamic conditions). Demonstration is given that only a few parameters, like temperature and chemical composition of the leachant, have an effect on leaching. A strong influence, however, is caused by the way of preparing the samples, which, in general, can strongly modify the final properties of cemented waste materials.
A Model of the Attack of Pure Water or Undersaturated Lime Solutions on Cement
Authors: Buil M , Revertegat E , Oliver J
Published: March 2009

A simplified model of cement attack by pure water or undersaturated lime solutions is proposed for long-term predictions of concrete degradation. The degradation is modeled by ionic diffusion in the cement pores coupled with mass exchange between the solid and aqueous phases. The local equilibrium hypothesis is discussed and justified for the present application. The only solid phases taken into account are portlandite [Ca(OH)2] and calcium-silicate-hydrate (C-S-H). The model predicts the existence of an undamaged core separated from the free surface being attacked by a sharp portlandite dissolution front with a progressive C-S-H decalcification zone located between this front and the surface. Good agreement has been found between the model and experimental results for the degradation of thin portland cement discs kept for three years in an undersaturated lime solution (1.6 mM/L). The model is completely determined with a few parameters measurable by simple tests (porosity, calcium and portlandite contents, diffusion coefficient). The model predicts a √t kinetics for the cement degradation (as long as an undamaged core remains).