bluuebunny/crossref_metadata_2025_split huggingface dataset:
Near-Threshold Fatigue Crack Growth Behavior for 316 Stainless Steel
Authors: Mills WJ , James LA 
Published: February 2009

Abstract
Fatigue crack growth threshold behavior of Type 316 stainless steel was studied in air at 24°C to evaluate the effects of load-shedding rate and specimen geometry on ultra-low crack growth rates. Load-shedding rates greater than the maximum rate recommended in the proposed ASTM test procedure were found to have no substantial effect on the threshold behavior. At very low ΔK levels, crack growth rates were apparently dependent on environmental effects and the degree of plastic constraint.
Monitoring of Oxide Layer Thickness on Zircaloy-2 by the Eddy Current Test Method
Authors: Sinha AK , Shah BK , Kulkarni PG 
Published: February 2009

Abstract
To ensure adequate wear resistance on some of the nuclear reactor components made of Zircaloy-2, a uniform thick buff oxide layer is desirable. Commonly used methods to evaluate oxide thickness (i.e., metallography and weight gain) have certain limitations. In this paper, results of eddy current (ECT) monitoring as a function of oxide layer thickness (determined metallographically) on Zircaloy-2 surface have been reported. A linear correlation between ECT response and oxide layer thickness has been established.
J-Integral Testing of Aluminum Alloys: A New Technique for Marking Crack Fronts
Authors: Beaver PW 
Published: February 2009

AbstractAn important aspect of the standardized JIc test method is the measurement of the amount of crack extension as a function of load. The usual method of marking crack fronts for subsequent measurement in a luminum alloys is to fatigue cycle after initial static crack extension.In this paper, a new technique for marking crack fronts in aluminum alloys is described. This new technique, based on liquid metal embrittlement of grain boundaries in aluminum by gallium, is, for the alloys examined in this work, a more effective method of crack front marking than fatigue cycling.
Determination of Material Characteristic Values in Elastic-Plastic Fracture Mechanics by Means ofJ-Integral Crack Resistance Curves
Authors: Roos E , Eisele U 
Published: February 2009

AbstractThis article discusses the problem of determining the characteristic values in ductile fracture mechanics on the basis of the J-integral. Special interest is directed towards the question of transferability of the characteristic values from laboratory specimens to large-scale specimens of dimensions similar to those of components.For this purpose technical substitute values and physical crack initiation characteristic values were determined from a number of specimens and a wide range of materials, showing the effect of material toughness and specimen geometry on the characteristic values. Technical substitute values were determined per ASTM (JIc), Loss et al. (J0.15), and Schwalbe and Heerens (J0.2). Determination of the physical crack initiation value resulted from measurements of the stretched zone.The technical substitute values and the physical crack initiation values were compared with results for large-scale specimens. Only the physical crack initiation value (Ji) correctly described the behavior of large-scale specimens regarding crack initiation.
A Dynamic Microindentation Apparatus for Materials Characterization
Authors: Polvani RS , Ruff AW , Whitenton EP 
Published: February 2009

Abstract
A microindentation system is described that provides a new approach to dynamic mechanical testing. The indentation is characterized in terms of continuous measurements of applied load and penetration depth. The indentation can be performed over a wide range of loading times from hours to milliseconds. The shape of the loading waveform can also be selected. The deformation energy can be measured and partitioned into elastic, plastic, and anelastic components. The apparatus is also able to perform conventional hardness testing, and may be useful for estimating conventional mechanical properties.
On the Analysis of Thermally Activated Tension-Tension Cyclic Deformation Behavior
Authors: Mshana JS , Krausz AS 
Published: February 2009

Abstract
The application of the transition state theory of rate processes to describe tension-tension cyclic deformation behavior was reviewed, leading to a coherent, unified theory for stress relaxation, creep, and strain and load controlled cyclic deformation. The study showed that over the stress, time, and temperature range where the rate of plastic flow can be approximated with activation over a single energy barrier, strain-controlled cyclic deformation is essentially a stress relaxation process, while creep is related to load-controlled cyclic deformation. The theory described well the deformation behavior of a near-eutectoid, zinc-aluminum alloy. The constitutive parameters determined from the analysis of stress relaxation, creep, and strain and load controlled cyclic loading experimental results were identical, leading to the conclusion that strain and load controlled cyclic deformations were different manifestations of the same basic process, depending on the control condition. Consequently, it was recommended that stress relaxation and creep can be employed to determine the constitutive parameters. By using the theory developed in this report, the cyclic deformation behavior can be predicted.
A Cleavage Precracking Technique for Sheet Steel Fracture Specimens
Authors: Clayton JQ , Rogers CB 
Published: February 2009

Abstract
A technique is described for the preparation of sheet steel fracture specimens containing a cleavage precrack instead of the usual fatigue precrack. Since the cleavage precrack can provide a high level of stress concentration and is free from cyclic-loading damage, such specimens are useful in the investigation of various fracture processes and mechanisms. The production technique involves low-temperature biaxial loading of a specimen blank to produce a cleavage crack extension, then separation of the specimen from the blank by electrical-discharge-machining (EDM). The stresses used to control the cracking are analyzed and discussed.
Diametral Strain Response and Microstructural Yielding Mechanisms of a Bainitic Pressure Vessel Steel
Authors: Rahka KA , Solin JP , Kemppainen MJ 
Published: February 2009

AbstractUnexpected trends of diametral strain range response have been recorded for annealed bainitic Cr-Mo-V-pressure vessel steel at room temperature and moderate strain amplitudes. Stress and diametral strain response were also recorded for three harder heat treatment variants, but they behaved as expected. The alloy is strengthened by a carbide dispersion and a dislocation network, both of variable density. The unexpected diametral strain response is suggested to be associated with yet unknown macroscopic effects of particular observed microscopic mechanisms of slip. These mechanisms of slip can be analyzed with a model for dispersion strengthening which expresses the connection between nominal dislocation activity and the plastic and elastic components of elongation. The necessity for a differentiation between effective obstacles to slip consisting of stable carbides or cyclically unstable dislocation networks is arrived at. Observation of slip mechanisms by scanning electron microscopy is presented.
Sampling Variance: Bias and Reproducibility
Authors: Savage KI 
Published: February 2009

Abstract
Product quality necessitates the collection of a representative sample for analysis. The representativeness of a sample is measured by its accuracy or variance. Sampling variance is discussed in two parts, bias and reproducibility. Bias is an error that consistently results in either high or low analysis. Test methods for bias are described in detail. Reproducibility is a measure of expected fluctuation around the true result. Reproducibility can be reduced by additional increments, analysis, or both.
An Evaluation Method for Comparing Domestic and Foreign Materials Specifications
Authors: Early JG , Hime HL 
Published: February 2009

Abstract
Consistent decisions on the degree of equivalence between metal specifications of different national origins cannot be made only on the basis of chemical composition and direct comparison of mechanical property numbers. There are numerous additional factors, which, if present, can influence the determination of equivalency because of their effect on property requirements. In order to remove the uncertainty in this decision-making process, these additional factors must be evaluated in each comparison. A generalized approach has been developed in which evaluation criteria have been identified and discussed in terms of their role in the determining of equivalence. These criteria are presented as part of a guideline for conducting material specification comparisons.
A Standard-Reference Water-Suspended Sediment Sample for Total Recoverable Metals
Authors: Fishman MJ , Malo BA , Boyle DK 
Published: February 2009

Abstract
The U.S. Geological Survey has been preparing and maintaining a library of standard-reference water samples for dissolved inorganic constituents for 19 years. Recently, the reference-sample program was expanded to include a water-suspended sediment mixture for the determination of total recoverable metals. An interlaboratory round-robin study was conducted. Digestion procedures used by the U.S. Geological Survey and the U.S. Environmental Protection Agency were used to solubilize the metals before their measurement. The data indicate the both digestion procedures for total recoverable metals are essentially equivalent. Precision data are comparable to those data obtained in standard-reference water samples for dissolved metals.
Simple Measuring System for Electrical Energy Consumed by Auxiliaries for Advanced Batteries
Authors: Futamata M , Takahashi S 
Published: February 2009

Abstract
We have constructed a new measuring system of electrical energy for widely varying load current between 0.5 and 100 A using a controller for the current transformers (CT), a personal computer, and wattmeters. This system possesses special characteristics as a controller circuit of the CT. When the load current changes greatly, the most appropriate first terminal of the CT is instantaneously selected by the controller to provide an accurate measurement.
Firstly, the response of the system to varying power factors is discussed. Electrical energy was measured to an accuracy of ±0.45% for constant current loads with power factors between 1.0 and 0.4 and to an accuracy of ±0.68% for on-off current loads at every 5 min with power factors of 1.0 and 0.9. Secondly, the effect of distorted waveforms is discussed with regard to the accuracy of the system. It was verified that the system was scarcely affected by firing angles of the load current between 45 and 135°. In conclusion, the measuring system is applicable to the auxiliaries of the 10 kW class advanced batteries and also to other general loads possessing various power factors and distorted waveforms.
Dynamic Properties of Asphalt Concrete
Authors: Sousa J , Monismith CL 
Published: February 2009

Abstract
This paper describes equipment developed to determine the dynamic properties of paving materials in axial and torsional loading. Dynamic properties were determined by the excitation of hollow cylindrical specimens using two independent sinusoidal loads with frequencies up to 30 Hz.
An IBM PC/AT equipped with a Metrabyte DASH16 Data Acquisition Board was used to directly control two MTS Hydraulic Servorams. Menu-driven software was developed, taking advantage of DMA channels, so that data acquisition, waveform generation, and closed-loop control could simultaneously take place at rates above 5000 samples/s/channel. To convert raw data into graphs and parameters representative of dynamic material properties, a post-processing menu-driven program was also developed.
Dynamic properties for a dense-graded asphalt concrete are presented for a range in temperatures from 11 to 40°C and for a range in frequencies from 0.5 to 20 Hz. Test results include: dynamic moduli in axial loading defined by |E*|, dynamic shear moduli defined by |G*|, internal damping determined in both axial and shear loading, and dynamic Poisson's ratios. Also included are results illustrating the effects of specimen density on these properties.
Comparisons are included of stiffness moduli determined in a repeated pulse load test (resilient moduli) with those determined from the dynamic load equipment. The data also indicate that some care must be taken when comparing stiffness values determined by this type of loading with those determined from sinusoidal loading, particularly at higher temperatures. Differences in the stiffness moduli may result from the influence of the time between load applications (rest periods) on the value of the recoverable strain used to compute the stiffness (resilient modulus) in the repeated load test.
Measurement of the Spherical Tip of Rockwell Indenters
Authors: Barbato G , Desogus S 
Published: February 2009

Abstract
Recent international comparisons of primary standards of Rockwell C hardness showed that the indenter shape is largely responsible for differences in measurement results. Measurements, especially of spherical-tip shape, made by means of high-magnification (500 ×) profile projectors proved to be affected by an uncertainty that also depended on the operator. In connection with such problems, a measurement system using a rotating table centered by means of an air bearing was developed together with a method for result analysis so as to allow the evaluations required by ASTM and ISO standards to be made quickly.
Prediction of Specimen Strain from Extensometer Deflection Measurements in a Direct Stress Fatigue Test Specimen under Static Tensile Loading
Authors: Arora PR , Raghavan MR 
Published: February 2009

Abstract
The displacement between the ridges situated outside the filleted test section of an axially loaded unnotched specimen is computed from the axial load and shape of the specimen and compared with extensometer deflection data obtained from experiments. The effect of prestrain on the extensometer deflection versus specimen strain curve has been studied experimentally and analytically. An analytical study shows that an increase in the slope of the stress-strain curve in the inelastic region increases the slope of the corresponding computed extensometer deflection versus specimen strain curve. A mathematical model has been developed which uses a modified length ¯ℓef in place of the actual length of the uniform diameter test section of the specimen. This model predicts the extensometer deflection within 5% of the corresponding experimental value. This method has been successfully used by the authors to evolve an iterative procedure for predicting the cyclic specimen strain in axial fatigue tests on unnotched specimens.
Sensory Attenuation Induced by Modern Athletic Footwear
Authors: Robbins SE , Hanna A , Jones LA 
Published: February 2009

Abstract
Disorders that impair sensory perception can cause serious injury. It has been proposed that many running-related injuries may result from wearing athletic footwear which induces changes in the perception of loads encountered during running. To test this hypothesis a psychophysical investigation was performed in which subjects were required to give numerical estimates of the perceived magnitude of a load experienced on the plantar surface. The loads were applied to the flexed knee, and the foot was supported on one of three different weight-bearing surfaces.
The results indicated that there was a linear relation between the size of applied load and the perceived magnitude of this load on all three surfaces tested. Subjects consistently underestimated the magnitude of the loads applied, with the greatest underestimation occurring when the foot was either on a rigid plastic surface or wearing athletic footwear. The exponents of power functions fitted to these data were all close to one which is similar to the values obtained in studies of the perception of skin indentation on the palmar surface.
The results from this study support the hypothesis that athletic footwear can attenuate the perceived magnitude of loads experienced on the plantar surface. This change in the perception of load may be a factor in running-related injuries for which the term pseudo-neuropathic is proposed, since there are no pre-existing neurological deficits.
This experiment alerts one to the need for product safety standards, particularly for athletic footwear, so that the public can be protected from the dangers that may be inherent in their design, since these devices are promoted for use in high-impact environments.
Sensitivity of Fatigue Crack Growth Prediction (Using Wheeler Retardation) to Data Representation
Authors: Finney JM 
Published: February 2009

Abstract
Using the Wheeler model for predicting fatigue crack growth as a case study, the likely errors in prediction from selecting literature calibration values are examined. From four methods of representing the same da/dN - δK data, errors in crack life prediction up to a factor of about three were obtained.
Because calibration values are stress scale dependent, the influence of interpolations and extrapolations on predicted crack growth life is also examined. Large extrapolations may lead to errors in predicted life, also approaching a factor of three.
Recent Scientific Developments That Affect the Assessment of Risk Posed by Trichloroethylene and Perchloroethylene
Authors: Jones RE , Byrd DM 
Published: February 2009

AbstractTrichloroethylene (TRI) and perchloroethylene (PER) are chlorinated hydrocarbons with similar chemical and toxicological properties. Cancer bioassay results with TRI and PER have shown increased incidence of liver tumors in B6C3F1 mice. Though the exact mechanism of tumor induction caused by TRI or PER is unknown, metabolic activation is strongly implicated. The major metabolite, trichloroacetic acid (TCA), induces peroxisomal proliferation (PP) in livers of rodents. Evidence suggests that PP in the liver is linked to the development of hepatic carcinomas. Whether PP is causative or just a by-product of liver cancer is unknown, but results establish that human cells do not react to TCA as rodent cells do. The current information on pharmacokinetics and mechanism-of-action for TRI and PER do not support a concern for carcinogenicity of exposed persons, based on findings of cancer in rodents. Moreover, the findings do not suggest a need for quantitative risk assessment.
Apparent Stiffness of a Butt Joint with a Thick Adhesive Layer and Elastic-Plastic Adhesives
Authors: Groth HL , Brottare I 
Published: February 2009

Abstract
The apparent stiffness of a thick adhesive layer in a butt joint is studied for adhesive materials with elastic-plastic material behavior. The finite element method was used for the determination of the joint stiffness as a function of the nominal strain. It was found that the stiffness obtained for the linear elastic case agreed with linear elastic solutions from the literature. Due to plasticity starting at the intersection of the adhesive and the adherend, the apparent stiffness of the adhesive layer decreases. The apparent stiffness reduction was not noticed below a nominal strain level of 0.5%.
Designing Bearing Fatigue Life Tests for Improving the Use of Testing Resources
Authors: Miller B , Hester D 
Published: February 2009

Abstract
A computer simulation study was conducted to investigate modifications of a current test plan for evaluating rolling contact fatigue life of experimental materials, so as to improve the use of testing resources and to produce more reliable data. The simulations revealed that a slight modification of the test plan, using available test rigs, could result in greater precision with fewer tests and a shorter average test duration.
Influence of Heat Treatment on Structure and Oxidation Behavior of Zr-2.5Nb
Authors: Ramanathan LV , Costa I , Monteiro WA 
Published: February 2009

AbstractThis paper presents the influence of different heat treatments on the microstructure and isothermal oxidation behavior of Zr-2.5Nb in oxygen. The quenched structure consisted of martensitic α′. Upon tempering the quenched alloy at 500°C for up to 100 h, βNb precipitated in the matrix, at twin and α′ needle boundaries. At higher tempering temperatures and after longer periods, Nb-rich βZr also precipitated. Specimens slowly cooled from the β-phase showed the least resistance to oxidation. The oxidation behavior also varied with the tempering time and temperature. The increased oxidation rate of specimens tempered at 500°C for 1000 h or at 600°C, as compared to those tempered at 500°C for shorter times, has been attributed to formation of Nb containing oxides on the coalesced Nb-rich precipitates and to cracking.
Cetane Number of Small Samples by Engine Throttling: Reliability Comparison with Standard Cooperative Fuels Research Method
Authors: Johnston RRM , van der Touw JW 
Published: February 2009

Abstract
The manifold pressure below which a diesel engine starts to misfire is related to the cetane number of the fuel. The method of engine throttling to misfire has been used to determine cetane quality of much smaller quantities of diesel fuel than can be used with the standard ASTM D 613 method. A comparison of reliability has been made between the two methods using identical test samples. The fact that published repeatability limits for ASTM D 613-84 are much smaller than the reproducibility limits suggests that there can be considerable bias at some laboratories using the standard method.
A method of calibration and computation is presented that provides reliable estimates of the accuracy of misfire pressure results without reference to other laboratories. Confidence intervals determined for the misfire pressure method are consistent with the observed difference in the results determined on the one set of test materials by the two methods. This suggests that, in the procedure for engine throttling to misfire proposed here, the interlaboratory component of error could be small.
Mechanical Evaluation and Performance Improvement of the Rotating Jaw Conibear 120 Trap
Authors: Cook SR , Proulx G 
Published: February 2009

Abstract
The momentum and clamping force values of a standard Conibear 120 rotating jaw animal trap and various modifications were determined using accelerometers and a load cell. These values were then compared against each other and against previous biological studies to determine which have the potential to quickly kill select species of animals.
It was found that by increasing the strength of the springs, and by adding clamping bars to the traps, it was possible to significantly increase both the momentum and clamping force of the standard Conibear 120 trap.
The Conibear 120 does not meet the requisites of the Canadian General Standards Board. More work should be done on traps, such as the C120 Mark IV, which do meet these requirements.
A Note on Dynamic Displacement Measurements Using Hall Effect Sensors
Authors: Giovanola JH , Kobayashi T , Klopp RW , Gaines T , Arwood R 
Published: February 2009

Abstract
We describe a transducer suitable for dynamic displacement measurements. The transducer uses a commercially available Hall effect sensor and a permanent magnet. Displacements are obtained by measuring the variation in magnetic field strength along the permanent magnet with the Hall effect sensor. To illustrate the capabilities of the transducer, we discuss three application examples. The first example demonstrates the good performance of the transducer under impact loading conditions and for velocities of up to 10 m/s. The other two examples illustrate the usefulness of the transducer for dynamic fracture experiments.