bluuebunny/crossref_metadata_2025 huggingface dataset:
Video Image Processing of Laser-Illuminated Coating Defects
Authors: Auborn JE , Moran MB
Published: February 2009

A video microscopy system has demonstrated the ability to detect and locate defects nondestructively in multilayer optical coatings. The system uses laser-excited scattering to illuminate defects responsible for laser-induced damage in multilayer dielectric mirrors. Scatter intensity maps and contours can be generated by digitizing the video image of scattering from individual defects. These can reveal characteristic defect scatter features that can be related to a damage probability. Due to the relatively low resolution of the stored video image, the scattering from a defect may be contained in only a few pixels. Using digital-enhancement techniques such as cross correlation, noise filtering, and Laplacian edge enhancement combined with fast-Fourier transforms, it is possible to increase the resolution of the characteristic features of a scattering defect for a more detailed analysis. Examples of these techniques for a dielectric mirror will be presented and discussed.
On the Role of Water in the Laser Conditioning Effect
Authors: Arenberg JW , Frink ME
Published: February 2009

This paper reports on a series of experiments designed to collect phenomenological data regarding the role of water in the laser conditioning effect. To understand the data collected, a model of the mechanism of laser conditioning is introduced. The model posited is that water included in the coating absorbs some of the incident laser energy and this increased absorption causes lowered damage thresholds. Further, it is assumed that, during the sub-threshold irradiation of the surface under test, water is desorbed before damage occurs. The decreased water content in the coating leads to higher damage performance due to the decreased absorption of the incident laser energy.
Optical Coatings for High-Power Nd-Lasers
Authors: Faizullov FS , Erokhin AI , Kovalev VI , Sagitov SI , Brauns B , Goepner V , Herrendorfer G , Schafer D , Wolf W , Zscherpe H
Published: February 2009

The influence of deposition technology and design of the dielectric optical thin film coating manufactured of refractory oxides and silicon dioxide on the damage thresholds of single and multilayer systems is investigated. It is shown that the damage threshold of reflection and antireflection coatings may be raised up to the damage threshold of pure glass surface for Nd-laser pulses in the range of 2 to 85 ns.
Sample Ranking vs. Damage Threshold Criteria in Small Spot Size Laser Damage Testing
Authors: Carson SD , Gorbett P , Seiffert SL , Ernest FP , Schumacher PM
Published: February 2009

Small spot size (3.5 mm) laser damage testing at 10.6 μn has been used on samples which consisted of metallic and metallic oxide coatings on polymeric substrates. Three degrees of damage were used to define damage thresholds. While absolute threshold values were different for each of the three levels of damage, sample ranking did not change. As long as consistency is maintained, the degree of damage used to define the damage threshold does not appear to be significant for small spot size testing for these samples, where the goal is to screen the effectiveness of a series of hardening concepts.
New Data Regarding the Thermal Laser-Damage Model and the Accumulation Phenomena in Silicon
Authors: Fry SP , Walser RM , Becker MF
Published: February 2009

In this paper we propose a new statistical framework from which to view laser-induced damage in silicon, particularly N-on-1 damage effects such as accumulation. To select between possible models for damage, we obtained a refined data set for the statistics of nanosecond pulsed Nd:YAG laser damage to Si surfaces. The implications of this data for modeling laser damage experiments will be discussed.
Intense-Field Optical Interband Excitations in Semiconductors and Insulators
Authors: Becker W , McIver JK , Guenther AH
Published: February 2009

We enumerate a number of difficulties which one encounters in a nonperturbative treatment of optical interband excitations in semiconductors and insulators
High Power Continuous Wave and Repetitive Pulsed Thermal Shock Laser Damage to Metallic Reflective Optics
Authors: Palmer JR
Published: February 2009

Thermal shock damage may be a precursor to the melting and disordering of metallic reflector surfaces. A number of investigators have reported in these proceedings the phenomena of slip fracture on the surfaces of both polished and diamond turned optics. In this paper, a model is presented using elastic-plastic technique coupled with the transient thermal response of an optical surface.

Equations are presented to reflect the thermal shock threshold for major metals that are commonly used for high power laser reflective optics. The models for the continuous wave and repetitive pulsed conditions have some similarities in evaluating the strain and rupture. However, because of the two cycle nature of the Repetitive Pulse condition, the thresholds are demonstrably lower than those that are shown for the Continuous Wave situation.
Deformation and Fatigue Damage in 1070 Steel under Thermal Loading
Authors: Karasek ML , Sehitoglu H , Slavik DC
Published: February 2009

The fatigue lives of 1070 steel (Class U wheel steel) under (1) isothermal loading, (2) thermo-mechanical constant amplitude loading, and (3) thermo-mechanical block loading have been examined. Fatigue lives for these three cases were compared based on the same mechanical strain range and maximum temperature level, with similar strain rates. Predictions of thermo-mechanical block loading cases were nonconservative based on isothermal data, while the predictions improved to within a factor of 1.5 of experimental lives when thermo-mechanical constant amplitude data were utilized.

Oxide scales readily formed at high temperatures (>500°C) and resulted in increased damage due to a localized high strain state and an inherent lack of ductility. Oxides of different composition and morphology form depending on the temperature and type of loading. Stratified and non-stratified oxide layers (predominantly Fe3O4) were identified in the experiments.
Growth of Small Cracks and an Evaluation of Low Cycle Fatigue Life
Authors: Hatanaka K , Fujimitsu T
Published: February 2009

Smooth and through-thickness cracked specimens of JIS S35C medium carbon and SNCM 439 alloy steels, heat-treated in several conditions, were low cycle fatigued. The growth rates of small surface and through-thickness large cracks, da/dN, were analyzed in terms of the cyclic J-integral range, ΔJ, and the strain intensity factor range, ΔKϵ.

The crack growth rates plotted against ΔJ and ΔKϵ are expressed by straight lines on a log-log diagram. The fairly large scatter inherent in a small crack problem hides some difference in the relations of da/dN versus ΔJ and the da/dN versus ΔKϵ plots between different materials. These relations in a small surface crack are slightly different from those in the through-thickness large crack.

The equations derived from combining these two relations and the cyclic stress-strain curve express well the fatigue life curves, of which slopes decrease in the lower plastic strain range in materials having a high strength and a low ductility, as well as the usual Coffin-Manson plot.
Application of the Overstress Concept for Creep-Fatigue Evaluation
Authors: Morishita M , Taguchi K , Asayama T , Ishikawa A , Asada Y
Published: February 2009

Type 304 stainless steel was subjected to a controlled push-pull strain with a wide variety of waveforms at 650°C in 0.1 μPa vacuum. No indication of oxidation was observed in the specimens. The frequency effect on creep-fatigue behavior was diminished, but the tensile hold time and waveshape effects were still observed in this high vacuum environment. It was concluded that a reduction of fatigue life due to creep-fatigue interaction is observed when a tension going time exceeds a compression going time. A back stress was determined from the data, and an overstress was defined as the difference between an applied stress and a back stress. The overstress was related to the inelastic strain rate. It is shown that overstress can be reasonably used to describe the creep-fatigue damages for life prediction.
Elevated-Temperature Low Cycle and Thermomechanical Fatigue Properties of AISI H13 Hot-Work Tool Steel
Authors: Engberg G , Larsson L
Published: February 2009

Thermal fatigue of the martensitic hot work tool steel AISI H13 is complicated by structural degradation which in turn is influenced by plastic deformation. These properties are dependent upon plastic deformation, temperature, and time, and thus it is of vital importance to find a description which allows inter- or extrapolation to the thermal load experienced in various practical applications.

Isothermal, low cycle fatigue testing was performed mainly at 500 and 600°C and also to a limited amount at 80, 300, and 750°C. The material was tempered to three different hardness levels (43, 47, and 51 HRC) prior to testing. The main bulk of tests were performed on the 47 HRC variant. At 600°C no difference in life was observed between the different hardness variants. The cyclic stress-strain curves, evaluated at half lives, were also almost identical. Softening is believed to cause this similarity, while the initial differences will only influence the behavior during a small fraction of the life after which all material differences will have vanished. Softening is due to particle coarsening and a decrease of the initially very high dislocation density. By assuming that Ostwald ripening takes place through volume diffusion, that the Orowan mechanism for particle strengthening is valid, and that the dislocation network spacing is directly proportional to the interparticle distance, a fair functional description of the experimental data is obtained. The temperature dependence of the solubility limit for the carbides and the activation energy for self-diffusion are nicely reflected by the data. The model predicts that a low solid solubility and a high volume fraction of the carbides will give rise to a low rate of softening as will a high strain-rate and of course a low temperature. Plastic deformation is found to increase particle coarsening significantly, but the extent is independent of the magnitude of the plastic strain within the limits investigated.

Thermomechanical fatigue testing (simultaneous cycling of both strain and temperature, half a period out of phase with one another) was performed with a maximum temperature of 600°C in the cycle. The minimum temperature, T-min, was varied from 80 to 400°C. In comparison to the isothermal 600°C data, life was reduced when T-min was less than or equal to 200°C, but remained fairly unaffected when a T-min of 400°C was used. As expected, softening increased with increasing minimum temperature.

The same hardness variants as described above were also tested with the 200 to 600°C cycle. No significant differences in life were obtained, although the cyclic stress-strain curves (maximum tensile stress at half life) differed. The Ostergren method for life prediction fit our data reasonably well if the plastic work is normalized with the cube of the shear-modulus.
Influence of Material Microstructure on Low Cycle Fatigue Failure, with Particular Reference to Austenitic Steel
Authors: Wareing J
Published: February 2009

A study has been made of the low-cycle fatigue behavior of austenitic stainless steels and a magnesium alloy over a wide range of temperature. The effects of microstructural variation on fatigue life of these materials which exhibit different crystal structures and deformation modes have been studied by thermo-mechanically treating material prior to testing and by inducing grain boundary creep cavitation during elevated temperature unbalanced creep-fatigue cycles. For balanced cycles microstructural changes result in moderate variations in fatigue life, despite changes in failure mode from trans- to intercrystalline. On the other hand, the introduction of discrete creep-type grain boundary cavities during elevated temperature unbalanced creep-fatigue cycles can cause an order of magnitude reduction in fatigue life. The effects observed in these two materials are rationalized in terms of current theories of fatigue failure and serve as a basis of assessing other materials.
Low Cycle Fatigue of Al-Mg-Si Alloys
Authors: Detert K , Scheffel R
Published: February 2009

The low cycle fatigue behavior of several age-hardened aluminum alloys with 1% Mg and 1% Si as alloying elements and varying Mn additions of up to 1% was studied. The alloy with the smallest grain size showed the highest strength as well as the highest low cycle fatigue strength. The number of cycles to failure represented by its dependency on strain range did not show any significant differences. However, one could derive from these results that one should try to reduce the number and size of inclusion particles in order to improve fatigue properties. In such a case one can expect that a small grain size of 20 μm diameter, Mn additions of 0.2 to 0.5%, and a polished surface with a roughness below 0.5 μm would be beneficial for low cycle fatigue properties.
Low Cycle Fatigue of Strain Aging Ferrous Alloys
Authors: Pickard SM , Guiu F , Blackie AP
Published: February 2009

The fatigue behavior of two high purity Fe alloys, one with 75 ppm (by mass) of both N and C and the other with 0.1% (by mass) C, has been investigated at 5 Hz. These alloys were heat treated to retain different solute concentrations, and it was found that the effect of increasing solute concentration was to increase the fatigue life and to suppress the “knee” in the S-N curve. It is shown that the flat appearance of the S-N curve is due to dynamic strain aging of the alloys. The Coffin-Manson analysis of the data shows that dynamic strain aging hardly affects the fatigue ductility of the material but produces an increase in yield stress sufficient to increase the fatigue life.

Fatigue predeformation and static aging at 60°C for 16 h produces a precipitation of metastable nitrides, or carbides, both at matrix sites and dislocations and an increase in the yield stress of the alloys. On retesting at the same stress amplitude, the plastic strain is found to have been considerably reduced and the fatigue life greatly increased, with a return of a “knee” in the S-N curve. The Coffin-Manson analysis reveals a great loss in fatigue ductility, but it is found that the cumulative strain to failure remains nearly constant at each stress level. This suggests that the influence of the increased strength by strain aging on fatigue life is more important than the reduction in ductility. The dislocation substructures developed at different amplitudes both before and after aging are correlated with the formation of slip bands and the nucleation of fatigue cracks.
Engineering Significance of Recent Multiaxial Research
Authors: GE Leese
Published: February 2009

Recent advances in multiaxial fatigue testing capabilities have provided the means with which to evaluate multiaxial life prediction techniques. As a result of the recent surge in testing, several key concepts have emerged as common threads in the results of contemporary multiaxial fatigue investigators. These concepts are discussed within the framework of three major areas: (1) effective stress-strain, (2) plastic work and energy, and (3) critical plane approaches. While general agreement within the technical community has not been reached on many fine points of analytical techniques and predictive expressions, their sensitivity with respect to multiaxial spectrum characteristics, physical interpretation, and ease of application has been described. It is suggested that surveying the present accomplishments will provide valuable insight for steering the future directions of multiaxial low cycle fatigue research.
Observations of Cracking Behavior in Tension and Torsion Low Cycle Fatigue
Authors: JA Bannantine , DF Socie
Published: February 2009

A series of tension and torsion low-cycle fatigue tests were conducted on several engineering materials. Detailed observations of nucleation and early crack growth were made. Cracking behavior is shown to depend upon loading mode (tension or torsion), strain amplitude, and material type.

Multiaxial models developed for shear sensitive materials did not correlate multiaxial test results of a tension sensitive material. Differences in cracking behavior for different materials and loading conditions need to be considered in successful life predictions for components subjected to multiaxial fatigue.
Some Contributions to the Further Development of Low Cycle Fatigue Life Analysis Concepts for Notched Components under Variable Amplitude Loading
Authors: H Nowack , W Ott , J Foth , H Peeken , T Seeger
Published: February 2009

In order to minimize the expenses of the development of engineering components and to reduce the risk of their operation, reliable fatigue life prediction methods have to be available in the design stage. Presently two groups of methods can be distinguished which explicitly account for the local stresses/strains in the fatigue critical areas: the so-called notch analysis concepts or “local approaches,” and new developments which are based on finite element methods (FEM).

In the first part of the paper typical areas in application of the notch analysis methods and some aspects of their further development are described. The significance of the short crack stage is briefly characterized from a physical and an engineering point of view.

In the second part the present state in the development of a new three-dimensional elasticplastic FEM-based fatigue analysis concept, FEMFAT, is described. FEMFAT uses a material model according to Mróz's proposal, and the fatigue damage is calculated on the basis of the plastic work as performed at the fatigue critical locations of components. A calculation scheme for the damage increments under arbitrary out-of-phase loading based on uniaxial data is proposed. Two examples of the application of FEMFAT are given.
Correlation Between Strain Singularity at Crack Tip under Overall Plastic Deformation and the Exponent of the Coffin-Manson Law
Authors: Y Murakami
Published: February 2009

This paper is concerned with the interpretation of the Coffin-Manson law Δεp·Nfα=C [1] from the standpoint of the behavior of small cracks and also with the explanation of the uniqueness of the exponent α from the strain singularity at crack tip under overall plastic deformation.

Firstly, the characteristic behavior of small cracks in low-cycle fatigue range is discussed; then it is demonstrated that the Coffin-Manson law is virtually identical to the growth law of a small crack. This suggests that we must pay attention to the behavior of a small crack in order to solve low-cycle fatigue problems. Secondly, the singularity of strain field at crack tip is analyzed by a finite element method. It is well known that, denoting the distance from the crack tip by r, the elastic stress strain field near crack tip has the singularity of r−0.5 and under the elastic-plastic condition the stress and strain has HRR singularity. However, under overall plastic deformation (i.e., under low-cycle fatigue range) the singularity in strain distribution near crack tip deviates from HRR singularity to r−(0.5∼0.7) with increasing plastic deformation regardless of hardening exponents of materials.

It is concluded from the viewpoint of the propagation of a small crack that this exponent (0.5 ∼ 0.7) in singular strain distribution is closely related to the fact that the exponent α in Δεp·Nfα=C ranges from 0.5 to 0.7 for various materials.
Notch Effect on Low Cycle Fatigue in Creep-Fatigue at High Temperatures: Experiment and Finite Element Method Analysis
Authors: M Ohnami , Y Asada , M Sakane , M Kitagawa , T Sakon
Published: February 2009

This paper describes the notch effect on low cycle fatigue in creep-fatigue conditions by experiments and finite element method (FEM) analysis. FEM analyses for cyclic and monotonic loadings were made, and the analytical results were compared with the measured strain at the notch root using a high temperature strain gage. The calculated strain by FEM agreed well with the measured strain if we used the proper FEM model and proper constitutive equation. In order to examine the accuracy of life prediction by FEM analysis, low cycle fatigue tests were also carried out using SUS 304 stainless steel for notched plate and notched round bar specimens. Life prediction by FEM analysis had sufficient accuracy; the applicability of other conventional life prediction methods was also discussed.
Anelastic and Elastic Measurements in Aluminum Metal Matrix Composites
Authors: Wolfenden A , Harmouche MR , Hayes SV
Published: February 2009

The piezoelectric ultrasonic composite oscillator technique (PUCOT) has been used at temperatures up to 638 K and at 80 kHz to measure dynamic Young's modulus E, mechanical damping or internal friction Q−1 and strain amplitude ϵ in Al/SiCw and Al/Sicp. For four adjacent specimens from one sheet of 6061 Al/SiCp E-values varied in the range 114–119 GPa at room temperature. The composition dependence of the modulus followed E = 68.6 + 2.2X with R = 0.95 (E is in GPa and X in volume percent SiC). The temperature dependence of the dynamic modulus followed E = 138.7 − 0.11T with R = 0.98 (E is in GPa and T in Kelvin). The amplitude dependence of Q−1 for 6061 Al/SiCw revealed a damping peak at ϵ = 10−6. An analysis of the internal friction data in terms of a damping theory yielded values for the minor pinning length of dislocation lines and the density of mobile dislocations. The results are discussed in terms of the microstructure.
Alternative Methods for the Determination of Shear Modulus in a Composite Material
Authors: Browne CM
Published: February 2009

The off-axis and ±45° axial tests are not only effective but also low cost methods for the determination of in-plane shear modulus in individual unindirectional lamina, because they avoid the difficulties of producing a pure state of shear stress experimentally. Possible test approaches for more general composites, including multidirectional laminates, are developed from an investigation into the transformation equations for orthotropic mechanical properties, laminate theory, and the mechanical advantages of the ±45° test. Other possible test approaches for the indirect determination of shear modulus in laminates and pultrusions are developed from the formulas used to correct for shear deformation in flexural test. The proposed tests should be more economical to perform than tube torsion or rail shear tests. They should also provide relatively uniform shear stresses over larger portions of the specimens than the notched specimen type tests.
On the Longitudinal and Transverse Tensile Strength and Work of Fracture of a Continuous Fiber Metal Matrix Composite Subjected to Thermal Exposure
Authors: Kyono T , Hall IW , Taya M
Published: February 2009

The mechanical properties of many metal matrix composites are known to be degraded when the metal matrix composite is subjected to thermal exposure. We have studied the effect of thermal exposure on the mechanical properties, namely, longitudinal and transverse strength and work of fracture of a boron fiber reinforced 1100 aluminum composite. It is found in this study that as the thermal exposure time increases, the longitudinal strength and work of fracture decrease, whereas the transverse strength increases slightly. The above experimental results are explained by analytical models, with reasonably good agreement between the experimental and analytical results.
Location of Potential Ground Subsidence and Collapse Features in Soluble Carbonate Rock by Remote Sensing Techniques
Authors: Kennie TJM , Edmonds CN
Published: February 2009

The occurrence of subsidence and collapse dolines in soluble carbonate rock is a frequent geotechnical hazard throughout the world. Such features pose serious geotechnical problems to engineering and building construction and also to public safety.

Detection methods utilized during preliminary site investigations range from direct methods, such as drilling, to indirect methods, such as ground geophysics and airborne remote sensing.

The aim of this paper is to examine the role of remote sensing in these preliminary site investigations. Previous and current remote sensing research concerned with the location of solution features is reviewed, with particular emphasis on airborne multispectral and thermal infrared line scanning. A comparative assessment of the relative merits of the different techniques is given, together with an examination of the factors which influence whether a particular technique will be successful.

The authors recommend that the most favorable detection results will be obtained if remote sensing methods are used under optimum environmental conditions and in appropriate geological conditions.
A Satellite-Based Investigation of the Significance of Surficial Deposits for Surface Mining Operations
Authors: Leach JHJ , Mallett CW
Published: February 2009

National Oceanic and Atmospheric Administration (NOAA) advanced very-high-resolution radiometer (NOAA-AVHRR), Landsat multispectral scanner (MSS), and shuttle imaging radar (SIR) imagery have been analyzed to determine their utility in evaluating parameters of geotechnical interest. This imagery has been used to determine the distribution, structure, and form of surficial deposits in the vicinity of large-scale mining operations. The data have been assessed in relation to specific problems encountered in large open-cut coal mines. The test sites chosen for this study are in the Bowen Basin of Queensland, Australia, where there are a number of very large open-cut coal mines. Some of these mines have slope stability problems in the pit walls and the spoil piles. Geotechnically important data on structural lineaments and the location and variation within surficial deposits have been acquired using these systems.

This paper presents the results of the study and points out the capabilities and limitations of the current satellite imaging systems. It also examines the potential of the next generation of satellite systems, such as the thematic mapper (TM) and Systeme Probatoire d'Observation de la Terre (SPOT), and discusses the characteristics of the ideal geotechnical remote sensing system.
Simulating Automotive Exposure for Corrosion Testing of Trim Material
Authors: Haynes GS , Baboian R
Published: February 2009

To predict the corrosion performance of trim materials on automobiles, it is important that the method of exposure as well as the test environment accurately reflect actual service conditions. The method of exposure must duplicate the various trim configurations. Variables which impact test results include the geometry of the test specimen and area relationships for galvanic effects. Test specimens fulfilling these requirements for trim materials are described. The results of tests in suitable environments for a number of trim systems on various auto-body materials are presented and compared with the service performance of the trim systems.
Automated Design of Composite Plates for Improved Damage Tolerance
Authors: Gürdal Z , Haftka RT
Published: February 2009

This paper is a first step toward automating the design for local damage tolerance of composite plates under compressive loadings simulating the local damage condition by a central through-the-thickness crack-like notch. Based on recent experimental investigations, the failure mode is assumed to be shear crippling, believed to be the result of kinking failure of the principal load-carrying fibers at a point of stress concentration in a laminate. The paper utilizes a microme-chanical failure model for the fiber kink formation in the load-carrying layers accounting for the combined effects of compressive and shearing stresses around the notch.

A previously developed code for cracked plates under tensile loading is used for the design purpose. The design code combines a finite-element analysis program with an optimization program and an automated mesh generation interface program. Minimum weight designs are achieved for stiffened and unstiffened plates subject to a constraint that a crack will not grow by fiber kinking failures. Design variables are ply thicknesses in different regions of the plates. Stiffened plates with four stiffeners that are assumed to be perfectly bonded to the plate section are considered. For stiffened plates, minimum weight configurations are obtained where the crack is isolated in low stiffness plate regions.
Characterizing the Tensile Stress-Strain Nonlinearity of Polyacrylonitrile-Based Carbon Fibers
Authors: Kowalski IM
Published: February 2009

It is well known that carbon fibers exhibit nonlinear stress-strain behavior with their axial modulus increasing as they are strained. An empirical model is proposed to take into account this nonlinearity by adding a second-order term to Hooke's Law. This modified Hooke's law has the form σ = E0ε + Fε2. The tangent modulus is found by differentiating with respect to strain, giving Etangent = E0 + 2Fε. The tangent modulus increases linearly with strain.

Data are presented on three material forms—composite, impregnated strand, and single filament—to validate the empirical model. The E0 and F elastic coefficients are determined by performing a least-squares fit to the quadratic model. Data are generated for T-700 and T-40 high-strength polyacrylonitrile (PAN)-based carbon fibers. The nonlinearity of the fiber is shown to be comparable in single filaments, impregnated strands, and uniaxial composites.

The experimental results show that the empirical model provides an excellent fit to the stress-strain behavior of the carbon fiber. The E0 and F elastic coefficients are repeatable in various resin systems and differ for each fiber type. The elastic coefficients determined by this method should be used in the design of composite parts that see high loading in the fiber direction. As an example, the initial modulus of a T-40 fiber is 263 GPa (38.1 Msi) and increases to a secant modulus at failure of 308 GPa (44.7 Msi), and increase of 17%.
Development of a Standard Quality-Control Test Method for Determining the Fiber Strength of Graphitized Roving
Authors: Kirshenbaum SL , Barker HJ , Dowell DW
Published: February 2009

A standard quality-control test method for determining the fiber strength of graphitized roving has been developed. Methods analyzed were (1) single filament, (2) dry strand between joints, and (3) impregnated roving. The single-filament test is currently the only test routinely employed for determining the quality (ultimate strength) of roving. Therefore, it was used as a standard for the other test methods being evaluated. A comparison is made between the three test methods with respect to the ease and time required for specimen preparation and testing, along with the accuracy and ability to reproduce strength results. The conclusion deals with the practicality and feasibility of each test with respect to this projects goal, along with recommendations as to the “best” test method.
A Constant ΔG Test for Measuring Mode I Interlaminar Fatigue Crack Growth Rates
Authors: Russell AJ , Street KN
Published: February 2009

A method for measuring Mode I interlaminar fatigue crack growth rates under constant strain energy release rate conditions is described and results are presented for two graphite fiber composite materials. The test consists of a uniform width and thickness DCB specimen which is loaded in series with a linear elastic spring in order to provide optimum control of ΔG. Tests are run under displacement control, and delamination extension is determined by monitoring changes in compliance. A nonlinear elastic relationship between load and displacement was required due to a nonlinear material response caused by fiber bridging. Fatigue crack growth rates were observed to decline by as much as a factor of ten over a distance of less than 5 mm although this varied depending on material, lay-up, and temperature. The fatigue crack growth behavior is compared with delamination extension under quasi-static loading and noticeable differences explained in terms of the micromechanisms responsible.
An Approach to Laboratory Data Management: The Applications Generating Programmable Data Base
Authors: May TW
Published: February 2009

A programmable data base, capable of generating complex application programs with management personnel, was investigated in order to facilitate the documentation requirements of Good Laboratory Practice Standards (GLPS). Emphasis was placed on developing a system that would be adaptable at the small independent laboratory level, that is, one that was limited in funds available for computerization and without high-level programming expertise. A successful system was developed around an enhanced IBM PC (XT) with the following software: the Sensible Solution relational data base, Volkswriter 3.0 word processor, and the Labcode-QC statistical quality control system. Application programs were developed as part of a total sample and data tracking system that featured distinct data categories: laboratory/field collection preparation methods or both; sample batch history; sample inventory listing; laboratory homogenization methods; chemical preparation methods; instrumental methods; final reports and other documents; current sample status; chemical, stock, and standard catalogue; control material catalogue; instrument service log; instrument/equipment calibration; personnel monthly time tracking. The system was developed easily without the expertise of experienced programmers and can be modified readily when needed.
Procedures for Assessing Secondary Poisoning Hazards of Rodenticides to Owls
Authors: Colvin BA , Hegdal PL
Published: February 2009

Monitoring of owl populations can be used to assess secondary poisoning hazards to nontarget wildlife from rodenticide use. An indicator species is chosen based on its likelihood to intercept treated areas and target species as well as its sensitivity to the toxic compound. Hazard evaluation includes monitoring of rodenticide-use patterns, radiotelemetry to document nontarget survival or mortality posttreatment, and necropsy and residue analysis. Data on the natural history of the nontarget species (for example, habitat use, foraging behavior) are necessary to interpret the degree of hazard to individuals. When a hazard to individuals is found, data on population dynamics are critical for interpreting the hazard to nontarget populations.
Evaluation of Rodent Bait Station Use Under Controlled Conditions
Authors: Kaukeinen DE
Published: February 2009

A method was developed to evaluate the responses of groups of wild Norway rats to bait stations. Groups of rats were first acclimated to test arenas of 5.6 m2 which each contained abundant harborage in the form of a covered pallet, drain pipes, and masonry blocks. Activity levels were measured daily by four methods: bait consumption, tracks, fecal counts, and motion detector (actimeter) counts. When activity had stabilized, one bait station containing an attractive nontoxic food and additional actimeters were added to each arena. Daily observations revealed changes in activity around the exterior of stations, time until entry, and the initiation and quantity of consumption of the station bait (unpoisoned EPA meal). In tests using the protocol, replicated comparisons were made of eight “tamper-proof” bait stations having various degrees of design complexity. In general, simpler designs showed more rapid and greater utilization and bait consumption. The method has application to evaluations with house mice and for studies of toxic baits in particular station designs.
Galvanic Corrosion Caused by Corrosion Products
Authors: Wilhelm SM
Published: February 2009

Experiments were conducted to quantify the magnitude of galvanic currents and potentials that exist between metals (iron, copper, titanium, aluminum, chromium, and nickel) and their corrosion products in oxygen-containing environments. Current measurements using a zero resistance ammeter and potential measurements of metal electrodes and oxide electrodes are reported. The effects of solution and electrode compositions on galvanic currents and potentials were determined. A galvanic series of corrosion products was constructed.

Galvanic interactions between metals and surface compounds are dependent on electronic conduction type (insulator, n-type, p-type, metallic) and thickness of corrosion product layers. It may be possible to modify semiconductor film conductivity by doping with impurity elements present as alloy constituents or via environmental addition and thereby mitigate galvanic corrosion.
Galvanic Corrosion in Oil and Gas Production
Authors: Efird KD
Published: February 2009

Published literature, service experience, and experimental data for galvanic corrosion in oil and gas production are reviewed and discussed. Data are presented in forms that can be used as aids for formal specifications, design criteria, and inspection requirements to help prevent galvanic corrosion failures: Emphasis is placed on downhole and wellhead applications, and oil and gas production equipment for carbon dioxide (sweet) and hydrogen sulfide (sour) environments. Particular attention is given to the effects of galvanic coupling on the noble metal and resulting failures. Galvanic corrosion in seawater environments is briefly reviewed as it pertains to seawater handling, offshore platforms, and subsea completions.
Transient Model of Early Stages in Compartment Fires
Authors: Takeda H
Published: February 2009

A new simple model of fire growth in a compartment is presented in this paper. The early stages in the compartment fires are modeled from the transient analysis of simple heat and mass transfer equations. Flame spread on the compartment floor, fire growth in a compartment and flashover are analyzed. The relationship between flashover time and A√H is investigated mathematically to compare with the experimental results. The purpose of this paper is to make a simple and reliable basis for fire modeling and to develop a user-friendly computer code.
Impact of Steel Quality on Integrated Automotive Wheel Bearing Performance
Authors: Tayeh GS , Woehrle HR
Published: February 2009

Quality and performance concerns have increased dramatically over the last ten years in the automotive industry. Demands on bearing steel internal quality as a means of improving bearing performance have reflected this trend. Meaningful measures of internal quality were vital to promote improvement, and SAM ratings of microinclusions were developed partly to serve this purpose. In addition, AMS 2301 magnetic particle inspection procedures were applied to measure macroinclusions. Cooperative work with numerous steelmakers led to significant cleanliness improvement as measured by these tools. Ongoing laboratory testing of thousands of bearings over the past seven years shows continuous bearing performance improvement attributable to many factors, among which internal steel quality plays a significant role. The internal laboratory bearing test data are also confirmed by long-term field performance as determined by a mathematical model, taking into account total bearings in the field, accumulated service, service sales, and service inventories. This model is in turn confirmed by failure mode analysis of failed components retrieved from the field.
Analysis of Microinclusions in Through-Hardening Bearing Steels
Authors: Lane S
Published: February 2009

An automatic optical image analyzer, the Quantimet 800 Steelscan, has been applied for microinclusion assessment in bearing steels according to the Stahl Eisen Prufblatt (SEP) 1570/71 method. A brief description of the system is given, including the use of electronic image amendment to distinguish reliably between different types of oxides.

Although the SEP comparison chart is well-formulated and should be sensitive enough for inclusion assessment of present-day bearing steels, results are presented showing that manual assessments with this method should suffer from very poor reproducibility. The automatic method has provided a more reliable basis for discriminating different degrees of inclusion content and, as a consequence, has highlighted the difficulty in obtaining a representative measurement of microinclusion content, especially in worked material such as bar or tube. The effects of deformation by rolling, sampling errors due to material inhomogeneity, and small variations in the orientation of the plane of sectioning on the microinclusion K ratings are discussed.

The limitations of comparison chart methods and automatic image analysis systems are reviewed, with emphasis on the required sensitivity for assessing bearing steels, as compared with an accurate chemical analysis of impurity elements for the prediction of microinclusion content.
The Effects of Ladle Refining, With and Without Vacuum, on Bearing Steel Quality
Authors: Whittaker DA
Published: February 2009

Three manufacturing procedures have been developed to produce bearing steels of varied cost and quality requirements: argon ladle refining, providing the lowest cost route for general bearing applications in C-Mn steels; argon ladle refining under full vacuum, for more specialized bearing applications in C-Mn and Ni-Cr-Mo alloy steels; and argon ladle refining under full vacuum plus vacuum arc remelting, for the highest cost and most critical bearing applications. Product qualities are discussed in terms of mechanical properties (hardenabilities, ideal diameters), chemistry control (C, Mn, S, O, Ti) and steel cleanliness (ASTM E 45, SAM, and AMS stepdown) ratings.
Properties of Through-Hardening Bearing Steels Produced by BOF Blowing Metallurgy and by Electric Arc Furnace with Ladle Metallurgy
Authors: Baum R , Böhnke K , Boeckers T , Klemp H
Published: February 2009

This paper discusses the cleanliness of through-hardening bearing steels produced by different melting and deoxidation processes. Macroscopic cleanliness is tested by the step-down and blue fracture test, and microscopic cleanliness is classified according to three rating methods. Cleanliness values of the air-melted heats are compared with remelted steels. Oxide inclusions are related to the oxygen contents of the heats, titanium-carbonitrides to the titanium contents, and sulfide inclusions to the sulfur contents of the heats. Machinability is effected more by carbide grain sizes than by sulfur contents. Ingot- and continuous cast steels are compared on cleanliness and segregation.
Use of Vollenweider-OECD Modeling to Evaluate Aquatic Ecosystem Functioning
Authors: Anne Jones R , Fred Lee G
Published: February 2009

The Vollenweider-Organization for Economic Cooperation and Development (OECD) models are statistical relationships that describe the functioning of aquatic ecosystems in the use of aquatic plant nutrients (nitrogen and phosphorus) for the production of planktonic algae. These models were developed on the basis of data from several hundred dodies of water throughout the world; those discussed herein define the relationships between normalized phosphorus loads to lakes and reservoirs and the planktonic algal chlorophyll, algal productivity, algal-related water clarity, hypolimnetic oxygen depletion rate, and fish yield. Guidance is provided on the use of these relationships for assessing the overall functioning of an aquatic ecosystem.
A Rapid Bioassay Using the Green Alga Selenastrum capricornutum to Screen for Toxicity in St. Lawrence River Sediment Elutriates
Authors: Ross P , Jarry V , Sloterdijk H
Published: February 2009

A toxicity bioassay using the green alga Selenastrum capricornutum and measuring inhibition of photosynthetic carbon-14 (14C)-labeled carbon dioxide (14CO2) assimilation is described. The essential test specifications are the following:

(a) experimental vessels: 16-mL test tubes;

(b) exposure and incubation times: 20 h exposure plus 4 h incubation;

(c) dilution water: demineralized H2O;

(d) algal cell density: 1.9 × 105 cells mL−1;

(e) radioactivity: 0.072 µCi mL−1, as 14C-labeled sodium bicarbonate [Na2(H14CO3)2];

(f) nutrient enrichment: 1 mL of × 10 provisional algal assay procedure (PAAP) medium; and

(g) isotope partitioning: acidification and bubbling.

The resulting method is rapid, sensitive, and reliable (coefficient of variation < 10%) and is applied to elutriates of St. Lawrence River sediments in an ongoing research project.
Effects of Complex Effluents on Photosynthesis in Lake Erie and Lake Huron
Authors: Bridgham SD , McNaught DC , Meadows C
Published: February 2009

Phytoplankton are the base of the food chain in most large lake ecosystems; if affected by environmental pollutants, significant ecosystem changes can result with potential impact on higher trophic levels. This research determined the effects of a complex effluent discharge from the River Raisin in Monroe County, Michigan, on the Lake Erie ecosystem. This river flows through southern Michigan and has large nutrient and industrial inputs, especially in the Monroe Harbor area. The functional parameters measured were bacterial uptake rate of acetate, zooplankton feeding and reproduction rates, and primary production. The results of the effects of complex effluents on gross photosynthesis, measured as carbon-14 (14C) uptake, are presented in this paper.

Intensive sampling was undertaken during the ice-free seasons of 1983 and 1984. In 1983, water from various stations in the River Raisin was mixed with eutrophic Lake Erie water at several dilutions. The rate of photosynthesis in the mixed samples was compared with with that of a control composed of Lake Erie water only. No clear trend in photosynthetic response was evident with increasing percentages of river station water. In 1984, oligotrophic Lake Huron water was substituted as the control, resulting in massive stimulation in photosynthesis with increasing percentages of river station water. There were increased levels of nutrients, toxicants, and algal biomass in the harbor area in relation to the Lake Huron control. The 1984 data were evaluated again after being weighted for the relative biomass of algae as 14C uptake, so that a nutrient-toxicant interaction could be examined. Using these simple linear mixing criteria, a gradient in toxicity was found, with the upstream area of the river causing stimulation of photosynthesis while the harbor stations caused inhibition at all concentrations of effluent. Extensive chemical and physical analyses were done on the station effluents and controls. An analysis of covariance on the 1984 data indicated that no single toxicant was responsible for the inhibition of photosynthesis found in the harbor area.

Results suggest that, in complex effluent tests when an oligotrophic control is used with eutrophic effluents, a weighting factor for the relative biomass of algae must be used. Predictable trends occurred when this was done in relation to the Lake Huron control. Tributaries with diverse anthropogenic inputs, such as the River Raisin, have the potential for significant inhibition of primary production in receiving bodies of water.