bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Material Inhomogeneities on Ultrasonic Measurements: The Problem and a Solution
Authors: Heyman JS , Cantrell JH 
Published: March 2009

Most ultrasonic measurements of materials involve the generation of an acoustic wave and the propagation of that wave from a transducer through a coupling medium to a specimen under test. After interacting with the specimen, the wave propagates through the coupling medium to a receiving transducer and is converted to an electrical signal. The information presented to the observer by the electrical signal depends on each element of the system.In this paper, we examine the role that the receiving transducer plays in ultrasonic measurements. The phase-sensitive nature of conventional receiving transducers has, for the most part, been neglected in nondestructive evaluations. This is shown to lead to significant data misinterpretation.A new acoustoelectric transducer (AET) has been developed which is phase insensitive. Comparative data obtained with both conventional and AET transducers are presented and discussed. The AET is shown to produce more accurate measurements for the cases investigated.
Experience of Element and Full-Bearing Testing of Materials over Several Years
Authors: Johnston GB , Andersson T , Amerongen Ev , Voskamp A 
Published: March 2009

A review is made of several years' experience in determining quantitatively the influence of material and production processes on the fatigue performance of rolling element bearings. This experience covers bearing testing and two different “element” test methods—the radial ball bearing with cylindrical inner ring and the thrust ball bearing with flat washer methods.
So far, it has been difficult to correlate the results from those element tests with results obtained from full-bearing tests. This is due to the special features of the concentrated point contacts between the balls and nonconforming surfaces used in the element methods. These features are an apparently random groove formation and a material transformation and failure mode different from those of normal bearings.
Use of Accelerated Tests to Establish the Lubricant-Steel Interaction on Bearing Fatigue Life
Authors: Eastaugh PR 
Published: March 2009

For several years the Royal Navy has used hydraulic fluids which differ significantly from the lubricants used by bearing manufacturers when establishing load to life characteristics. The performance of relevant fluids has been assessed in conjunction with standard EN31 (AISI 52100) steel test specimens using two standard test machines (the rolling four-ball and Unisteel) and a rolling contact fatigue rig designed and built in the author's department.
In addition, a high speed rolling four-ball machine is being commissioned. The test results show that wide variations in performance occur with different lubricant-material combinations, and it is necessary to run tests at several different levels of severity in order to predict service performance reliably. The standard rolling four-ball test did not give good correlation with other test data, and a metallurgical investigation of some failed specimens suggests that an abnormal failure mechanism could be operating.
Rolling Contact Fatigue Mechanisms—Accelerated Testing Versus Field Performance
Authors: Zwirlein O , Schlicht H 
Published: March 2009

Cycling tests in the laboratory serve to assess the qualitative and quantitative influences of specific parameters on the service life of rolling bearings by systematically varying these parameters in the tests. The applicability of the test results to the field is a precondition for the optimization of material and design.
Material stress is analyzed and described by various alterations in the material caused by cyclic stressing. The conditions under which cyclic stressing generates structural alterations are demonstrated. This paper refers especially to the influence of different contact pressures and residual stresses on material stress and the failure mechanism at cyclic stressing.
KIc and JIc of Westerly Granite—Effects of Thickness and In-Plane Dimensions
Authors: Schmidt RA , Lutz TJ 
Published: March 2009

An investigation is described in which tensile properties, fracture toughness, and critical J-integral are measured for Westerly granite, a rock that is used widely in rock mechanics studies. This was primarily a parameter sensitivity study in which the effects of specimen dimensions and testing techniques were assessed. It is hoped that this study will aid in establishing tentative standards and guidelines for fracture toughness testing of rock as well as indicate the feasibility of using a J-integral fracture criterion for this material.
ASTM standard specimen configurations of the compact and bend types were tested with compact specimens ranging in width from W = 25.4 mm to W = 406.4 mm (0.5T to 8T) and with thickness ranging from 13 to 100 mm. A series of 4T compact specimens were tested to assess the effects of thickness and fatigue precracking.
Techniques are described that enable several values of KIc, a complete J versus crack growth curve, and a JIc value to be obtained from each sample. Direct-pull tension tests on shaped specimens of Westerly granite are described which indicate a high degree of nonlinear, inelastic behavior. This fact raises questions about the use of linear elastic fracture mechanics, LEFM, but the JIc data presented appear to validate the KIc measurements.
Further Evidence of Zircaloy Corrosion in Fuel Elements Irradiated in a Steam Generating Heavy Water Reactor
Authors: Sumerling R , Garlick A , Stuttard A , Hartog JM , Trowse FW , Sims P 
Published: March 2009

An earlier paper (Trowse et al, ASTM STP 633) described the nodular corrosion of Zircaloy and other zirconium alloys in a steam generating heavy water reactor (SGHWR) and related environments. The observations have now been extended to more highly irradiated elements up to the design burn-up of 20 MWD/kgU mean. Maximum observed local oxide thicknesses were less than the earlier predictions of 200 μm for SGHWR cladding at the design burn-up and are acceptable from fuel performance considerations.
Most of the data presented relates to Zircaloy-2 in the stress-relieved condition, but results from elements with recrystallized cladding show that oxidation resistance can be improved by this treatment. In particular, the oxide nodules are much finer in the recrystallized alloy, leading to a generally smaller coverage of nodular oxide.
The maximum depth of oxidation is correlated to fast neutron dose and is apparently little affected by coolant mass flow-rate or steam quality.
Previous work had shown evidence for oxidation enhancement of Zircaloy at support grid positions by galvanic coupling to stainless steel and also by localized coolant flow disturbance. In order to determine the relative importance of these two factors, an experimental element fitted with alternate stainless steel and Zircaloy grids of similar geometry was irradiated in SGHWR. The results confirmed that most of the oxidation enhancement is due to the galvanic coupling but that significant flow effects at grids were also present in the higher flow, higher steam quality region of the element down-stream of the peak flux position.
Irradiation Growth in Cold-Worked Zircaloy-2
Authors: Murgatroyd RA , Rogerson A 
Published: March 2009

Irradiation growth has been studied in 25 percent cold-worked Zircaloy-2 at temperatures of 353 and 553 K. At 353 K, a rapid increase in growth strain occurs at doses less than 1024 n/m2 (neutrons per square metre) followed by a linear growth rate at higher dose. At 553 K, significantly lower strains are attained upon irradiation to 1024 n/m2, but the subsequent growth rate is higher. Thus, at a dose of about 1025 n/m2, the growth strains achieved at the two temperatures are similar. The data have been fitted to both linear and power law relationships, and comparisons are made with data reported for both annealed and cold-worked Zircaloy-2.
Two important effects of temperature have been established. First, at doses less than 5 × 1024 n/m2, growth in cold-worked Zircaloy-2 at 553 K is significantly less than at 353 K. Second, at 353 K, growth in 25 percent cold worked Zircaloy-2 is linearly dependent on dose above a dose of 1 × 1024 n/m2; this contrasts with the growth saturation observed in annealed material irradiated at the same temperature.
The observed growth behavior is interpreted in terms of a growth model consisting of two temperature-dependent components; one due to the nucleation and growth of small defect clusters and loops during the early stages of irradiation, and a second due to the preferential absorption of interstitials at the existing dislocation structure.
Iodine-Induced Stress Corrosion Cracking of Fixed Deflection Stressed Slotted Rings of Zircaloy Fuel Cladding
Authors: Sejnoha R , Wood JC 
Published: March 2009

Stress corrosion cracking of Zircaloy fuel cladding by fission products is thought to be an important mechanism influencing power ramping defects of water-reactor fuels. We have used the fixed-deflection stressed slotted-ring technique to demonstrate the following:
1. Hydride layers plated electrolytically onto the surfaces of Zircaloy rings, cut from a batch of cold-drawn material, either increased the time to failure or prevented cracking in iodine vapor at 573 ± 3 K, giving rise instead to a generalized pitting attack. The presence of hydride changed the cracking mode from mainly transgranular cleavage to mainly integranular cracking.
2. In two batches of tube-reduced Zircaloy tubing, one annealed and one as-received, cracking could not be induced in iodine vapor at 573 ± 3 K even with axial scratches on the inside surface. However sharp precracks did propagate readily when their depths and the applied stresses were great enough.
3. One batch that had remained intact when tested in the as-received condition cracked readily in iodine vapor at 573 ± 3 K after stress relief. In the stress-relieved tubing, prescratching did not affect failure times, and cracks nucleated away from the notches. This contrasted with tests in methanol-iodine at room temperature, where notches shortened failure times substantially, the cracks nucleating at the notches.
The results show both the sensitivity and limitations of the stressed slotted-ring method in determining the responses of tubing to stress corrosion cracking. They are interpreted in terms of stress relaxation behavior, both on a microscopic scale for hydrogen-induced stress-relief and on a macroscopic scale for stress-time characteristics. Our analysis also takes account of nonuniform plastic deformation during loading and residual stress buildup on unloading. It is shown that when stress corrosion cracking occurred, it was in conditions where stress relaxation was sufficiently slow that the applied stress exceeded the critical stress for stress corrosion cracking, which itself is a function of exposure time and also the metallurgical condition of the tubing.
Embrittlement of Zircaloy-Clad Fuel Rods Irradiated Under Film Boiling Conditions
Authors: Hobbins RR , Seiffert SL , Ploger SA , Mehner AS , MacDonald PE 
Published: March 2009

Pressurized water reactor type fuel rods are being irradiated under postulated accident conditions in the Power Burst Facility at the Idaho National Engineering Laboratory as part of the Thermal Fuels Behavior Program. In these tests, film boiling was achieved by establishing a mismatch reactor power and coolant flow, while maintaining the coolant pressure at 15 MPa.
Cladding embrittlement resulting from film boiling operation of intact fuel rods was found to be consistent with previously established embrittlement criteria based on oxygen content in β-Zircaloy, but not with previously established criteria based on either fractional thickness of transformed β or equivalent cladding reacted.
Rods that were operated with breached cladding were embrittled to a greater degree than intact fuel rods under similar oxidizing conditions. This embrittlement appears to be associated with rim α and acicular α precipitation within the transformed β field as well as with enhanced hydrogen absorption.
Relationship Between Response Parameter Hierarchies, Statistical Procedures, and Biological Judgment in the NOEL Determination
Authors: Javitz HS 
Published: March 2009

The U. S. Environmental Protection Agency recommended protocol for the fathead minnow life-cycle test specifies the measurement of numerous basic, but fragmentary, response parameters. Various researchers have recognized the need for combining those basic responses into global responses, which are more indicative of species survivability and ecological impact. One method of satisfying this need is to construct a hierarchy of responses. We illustrate a hierarchy of responses, currently being used in SRI experiments on munitions wastewaters, which consists of 31 basic responses (including new cumulative survivability responses) and 4 global responses.
The use of a hierarchy of responses including global responses necessitates the development of statistical tests for these responses and highlights the problems associated with potentially large overall significance levels. The use of Dunnett's test for assessing the statistical significance of the global responses is recommended along with the subdivision of aquaria to provide adequate degrees of freedom. In addition, we discuss methods for accurately estimating and reducing the generally unacceptably large overall significance level associated with the policy of declaring a concentration to be above the no-observed-effect level (NOEL) whenever any response is statistically significant.
The importance of incorporating biological judgment and expertise into the NOEL decision is gaining recognition, and a schema for this incorporation is presented. Methods for modifying the statistical tests to detect only biologically important response differences and statistical and graphical techniques for assisting the application of biological judgment are examined. The application of biological judgment in the NOEL decision is found to lower the overall significance level, and a method (postrandomization) for estimating that reduction is presented.
Considerations in the Design and Analysis of Chronic Aquatic Tests of Toxicity
Authors: Feder PI , Collins WJ 
Published: March 2009

Some considerations in the planning of toxicity tests and in the reporting of results are discussed. The need for using standardized stocks of fish and standardized data recording and data reporting procedures is argued. Standardized sheets for reporting hatchability data are presented as an example of a number of standardized data reporting sheets developed by the authors.
We consider aspects of the statistical analysis of data arising from aquatic toxicity tests. The discussion emphasizes analyses and data displays for the interpretation of qualitative mortality and abnormality data, but the ideas pertain also to other types of data.
The techniques discussed include preliminary graphical displays, tests for homogeneity among tanks within treatment groups, adjustments to account for tank-to-tank heterogeneity within groups, outlier detection procedures, overall tests for treatment effects, multiple comparisons and pairwise confidence intervals of treatment groups with the control group, and dose-response curve fitting with associated estimates of “safe concentrations.”
Development of a Sperm Cell Toxicity Test for Marine Waters
Authors: Dinnel PA , Stober QJ , Crumley SC , Nakatani RE 
Published: March 2009

Preliminary methods for conducting a quick and sensitive sperm cell toxicity test for marine waters have been developed. This paper presents a simple static test in which sea urchin or sand dollar sperm cells are exposed to test or control solutions for short periods of time (typically 15 to 60 min). Eggs are added to the test containers after the sperm exposure period has ended, and a standard time is allowed for fertilization to take place before the eggs are fixed with formalin. Samples are then tabulated for fertilization success by noting the presence or absence of the fertilization membrane. The results are analyzed by standard statistical methods to yield a time-dependent median effective concentration (EC50) (that is, the concentration of the test material that is effective in reducing fertilization success by 50 percent) after a specified period of exposure.Sperm cell toxicity tests with two reference toxicants (silver nitrate and the pesticide endosulfan) showed that toxic responses were directly related to sperm exposure time. The 60-min EC50s and 95 percent fiducial limits for green sea urchin (Strongylocentrotus droebachiensis) sperm were 76 (57 to 103) and 168 (99 to 285) µg/litre for silver and endosulfan, respectively. The 60-min EC50s for sand dollar (Dendraster excentricus) sperm were 45 (34 to 61) and 147 (123 to 175) µg/litre for silver and endosulfan, respectively. Matrix bioassays using temperature, salinity, and toxicant concentration as variables showed that the toxic response to both silver and endosulfan generally increased with increasing temperature and decreasing salinity. One test series of silver and endosulfan in combination showed that toxicity was additive. Comparative sea urchin and sand dollar embryo tests (72 to 96 h) showed embryo sensitivity to be similar to sperm sensitivities with levels of effect (retardation of development) of 50 and 25 µg/litre, respectively, for silver and 253 and 158 µg/litre for endosulfan.Additional development and refinement of this sperm cell toxicity test should yield a rapid and sensitive procedure for screening large numbers of toxicants in marine waters, aid in the prediction of ecological effects, and provide an additional tool for the biomonitoring of receiving water quality.
Effect of Linear Alkylbenzene Sulfonate on the Structure and Function of Microbial Communities in Model Ecosystems
Authors: Larson RJ , Maki AW 
Published: March 2009

The effect of linear alkylbenzene sulfonate (LAS) on the structure and function of microbial communities was studied in a flow-through model ecosystem containing several trophic levels. The LAS was supplied to 19-litre glass aquaria at 0.5 and 5.0 mg/litre in either well water (Phase I) or sewage effluent (Phase II). The structure of microbial populations was estimated from measurements of total viable biomass; function assays consisted of measuring rates of glucose or LAS degradation, or both. Assays of microbial function were also carried out in waters from two rivers.
The results of Phase I studies indicated that LAS had no effect on microbial structure at either dose level. Microbial function was also unaffected at the low-dose level, although both glucose and LAS degradation were inhibited at the high-dose level. By contrast, 5 mg/litre LAS had no effect on microbial function in river water exposed to sewage effluent, as measured by the rate of LAS degradation. Similarly, there was no decrease in function of the microbial populations exposed to ∼5 mg/litre LAS in the Phase II model ecosystem. It was further noted that the overall kinetics of LAS degradation in Phase II model ecosystems were essentially identical to those in two river waters. From Phase I and Phase II studies the following were concluded: 1. Function measurements were preferable to structure measurements in characterizing mixed microbial communities. 2. The function of microbial communities in relatively simple model ecosystems closely approximates that of natural populations in surface waters.
Comparison of a Luminescent Bacterial Test with Other Bioassays for Determining Toxicity of Pure Compounds and Complex Effluents
Authors: Qureshi AA , Flood KW , Thompson SR , Janhurst SM , Inniss CS , Rokosh DA 
Published: March 2009

A variety of chemical compounds and complex effluents were evaluated for toxicity using a luminescent bacterial test, and the results were compared with those of the rainbow trout, Spirillum, and Daphnia static bioassays. Direct correlations of the results were difficult as these assays utilize organisms of different levels of biological complexity. The data, however, demonstrated that in the majority of cases the luminescent bacterial test sensitivity was comparable with that of the rainbow trout, Spirillum, and Daphnia bioassays; particularly for organic compounds and complex effluents. Furthermore, this test appears to be relatively inexpensive, rapid, and simple, requires small sample volumes, and generally provides good reproducibility.
While the luminescent bacterial test has potential as a valuable tool for short-term toxicity testing of effluents and specialty chemicals, it may be a poor indicator of toxicity for wastewaters containing certain specific compounds (such as ammonia or cyanide). Moreover, the test alone cannot substitute for acute or sublethal hazard assessment. It is therefore recommended that the luminescent bacterial test be used in a battery of screening tests or to supplement other well-established toxicity bioassays.
Investigations in Aquatic Behavioral Toxicology Using a Computerized Video Quantification System
Authors: Miller DC , Lang WH , Greaves JOB , Wilson RS 
Published: March 2009

The effects of pollutants on the behavior of aquatic organisms are being investigated for the purpose of developing behavioral tests applicable to routine toxicological assays. Although behavioral responses are known to be valuable in detecting the biological effects of certain types of pollutants, behavior has rarely been used in routine assays because of the difficulties in making observations and in quantifying behavioral change. We have reduced these problems appreciably through the use of a closed-circuit television system and the quantification of the behavioral record by computer. The behavioral analysis system used is an on-line interactive system capable of analyzing linear and angular parameters of motion for groups of organisms recorded simultaneously. It may be adapted to study material ranging in size from bacteria to fishes.
The findings are presented on the effects of copper and cadmium on selected behaviors of Stage II and III nauplii of the barnacle Balanus improvisus. Both metals alter nondirected (spontaneous) swimming activity in a dose-related biphasic manner, with hyperactivity usually occurring initially, followed by suppressed activity. Copper also alters phototaxis in these nauplii, thus reducing the percentage of individuals displaying positive phototaxis and, at higher concentrations (72 and 138 ppb), causing a shift to negative phototaxis in some individuals. The sensitivity of these behavioral responses is compared with two developmental parameters monitored during the same assay.
Behavioral tests may provide important information for hazard evaluation. Each behavioral alteration observed here may have adverse ecological implications. In addition, tests of nondirected activity and directed responses of aquatic organisms may also be valuable as routine screening tools to identify chemicals toxic to neural or motor systems.