bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Hierarchical Model-Based Control System for Inspection
Authors: Hopp TH , Lau KC 
Published: December 2008

A control system architecture for three-axes coordinate-measuring machines, using hierarchical task-decomposition techniques, is described. This architecture is based on real-time, sensory-interactive control concepts developed at the National Bureau of Standards (NBS). An inspection program consists of a series of high-level goals to be satisfied. Goals are satisfied when specified information has been obtained regarding the part. There is a decision hierarchy, each level of which provides logic for partially decomposing goals into simpler goals. The control system executes the inspection program by interpreting the decision hierarchy logic. The lowest level of the decision hierarchy generates primitive coordinate-measuring machine actions, which are directly executed. A world model hierarchy executing in parallel with the task decomposition hierarchy provides information which aids in the decomposition decisions at each level. The world model is derived from a combination of prior knowledge of the part and observations gathered during inspection. The use of a world model allows an inspection task to adapt to the particular part being inspected.
It is expected that control architecture described here will provide new research opportunities in various areas of computer-aided design/computer-integrated manufacturing (CAD/CAM). The experience at NBS in using a similar architecture for robot control systems indicates that this system can naturally incorporate new inspection technology such as continuous tracing and vision. The system will also be used in various research efforts in the area of standards. These include the development of techniques for incorporating quality assurance standards into inspection tasks, development of languages for communicating inspection programs between different systems, and identifying n new data requirements for CAD representations of parts.
Slow-Strain-Rate Testing of Al 7075-T6 in Controlled Atmospheres
Authors: Khobaib M , Lynch CT 
Published: December 2008

The stress-corrosion-cracking (SCC) susceptibility of Al 7075-T6 alloys has been studied in a controlled-atmosphere chamber utilizing the slow-strain-rate technique. The effects of high-humidity air with small additions of sulfur dioxide, nitrogen dioxide, and surface salts in different combinations have been investigated to predict the behavior of industrial environments. The slow-strain-rate technique has been used to optimize the simulated environments which result in accelerated crack growth and failure by SCC in high-strength Al 7075-T6 alloy. These controlled environmental tests provide initial data on the environmental susceptibility needed for the development of realistic accelerated-corrosion testing methods. The design of the environmental chamber for providing controlled atmospheres is discussed and initial experimental results are presented.
Most tests were conducted at 80 to 90% relative humidity. The SO2 concentration was varied from 10 to 1000 ppm, while NO2 was maintained to 100 ppm. Small amounts of surface salts were obtained by rapid immersion in aqueous salt solutions. The susceptibility of the alloy shows significant differences that are dependent upon the specific environmental contaminants. Synergistic effects in several environments were found to maximize the environmental effects upon crack growth in stress corrosion. In a related study, these effects were demonstrated in corrosion-fatigue experiments under similar conditions. The qualitative estimates of embrittlement in the fracture surfaces were consistent with slow-strainrate results. The data provide the basis for the development of accelerated corrosion tests in realistic atmospheres.
Variation in the Strain Anisotropy of Zircaloy with Temperature and Strain
Authors: Hindle ED , Worswick D 
Published: December 2008

The strong crystallographic texture which is developed during the fabrication of zirconium-based alloys causes pronounced anisotropy in their mechanical properties, particularly deformation.The tendency for circular-section tension specimens with a high concentration of basal poles in one direction to become elliptical when deformed in tension has been used in this study to provide quantitative data on the effects of both strain and temperature on strain anisotropy. Tension tests were carried out over a temperature range of 293 to 1193 K on specimens machined from Zircaloy-2 plate. The strain anisotropy was found to increase markedly at temperatures over 923 K, reaching a maximum in the region of 1070 K. The strain anisotropy increased with increasing strain in this temperature region.The study was extended to Zircaloy-4 pressurized-water reactor fuel cladding by carrying out tube swelling tests and evaluating the axial deformation produced. Although scatter in the test results was higher than that exhibited in the tension tests, the general trend in the data was similar.The effects of the strain anisotropy observed are discussed in relation to the effects of temperature on the ductility of Zircaloy fuel cladding tubes during postulated large-break loss-of-coolant accidents.
Combustible Linings and Room Fire Growth—A First Analysis
Authors: Magnusson SE , Sundström B 
Published: December 2008

A computational procedure has been developed to correlate a full-scale room fire test process and results from the proposed International Organization for Standardization (ISO) small-scale laboratory tests. The analysis assumes that the combustible lining material covers ceiling and walls. Derived material characteristics and test room time lag factors are used as input data to an uncomplicated mathematical expression, essentially describing the full-scale test fire process as a concurrent flame spread phenomenon. Undetermined parameters in the model have been derived using linear regression analysis and results from seven full-scale room tests. In these room tests, the tested materials were of such thickness that no burning through occurred. Using results from the regression analysis, a simulation of the fire growth behavior can be carried out, including the adjustments needed due to transportation time lags and instrument response time. The predictive capability was thought acceptable, but further experimental confirmation and sensitivity studies are needed to assess the inherent variability. Qualitatively the regression equation predicted the same relative ranking of materials as the room test.
For thin surface finish materials on a noncombustible base, it was possible to derive a radically simple expression to be used as indication of the risk of flashover. Again, the final usefulness only can be evaluated on the basis of further experimental evidence.
In summary, it is thought that a first step has been taken in the efforts to use results from small-scale tests to rationally predict full-scale fire growth (for one specified scenario) and rank materials.
Fatigue Life Estimates for a Simple Notched Component Under Biaxial Loading
Authors: Fash JW , Socie DF , McDowell DL 
Published: December 2008

Three-dimensional stress-strain fields are routinely determined for complex components using elastic and elastic-plastic finite element models. Although the local stress-strain response can be easily determined, the proper approach to strain based multiaxial fatigue analysis is not clear. Several multiaxial fatigue theories have been suggested, but there exists a lack of consensus on which model is most appropriate. To clarify the situation, experiments have been performed on two different multiaxial specimen geometries. Results are compared with theoretical predictions.
Thin-walled tube specimens have been tested using combined in-phase tension-torsion loading. This specimen geometry has a simple uniform stress-strain state. Tests were also performed using a solid notched shaft specimen subjected to inphase torsion-bending loads. Stress-strain gradients exist in the notch root. Local multiaxial stress-strain fields were determined using an elastic-plastic finite element model.
Five current multiaxial strain based fatigue theories have been developed to correlate the experimental results. Fatigue life estimates were based upon uniaxial strain controlled fatigue data.
Correlations for the thin-walled tube test series were within a factor of 3 in fatigue life. For the notched shaft specimen with the more complex stress-strain state, life estimates were in error by a factor of 10 in fatigue life. This suggests that the effects of geometry are as important as the selection of the fatigue theory. Much additional work needs to be done to understand the effect of notches in multiaxial fatigue before these methods can be routinely implemented by designers.
How Representative are the Data Sets Used to Derive National Water Quality Criteria?
Authors: Seegert G , Fava JA , Cumbie PM 
Published: December 2008

One of the key assumptions implicit in developing national water quality criteria is that the data base used to derive the criteria includes data from a reasonable cross section of the aquatic communities to be protected. This requires testing not only a large number of species but those species that represent a variety of taxonomic and functional groups. Implicit also is the assumption that the species tested represent the full range of sensitivities expected in the population as a whole and that neither overly sensitive nor resistant species are unduly represented in the data base. Examination of the national toxicity data base indicated that the toxicity data which it contains does not meet these assumptions because (for 21 priority pollutants) 40% of the data are on a few regularly tested species such as bluegill and fathead minnow and one quarter of the data are on only two families. Daphnidae and Salmonidae. Furthermore, for many chemicals, many of the species that have been tested are restricted to the northeastern and/or upper midwest portions of the United States. The problem of nonrepresentative testing is further complicated by the fact that toxicity data for some of the commonly tested species (e.g., rainbow trout) are often replicated and verified by several investigators, whereas data on other species are not. This is particularly true of the toxicologically sensitive species. Finally, the evidence suggests that sensitive species may be overrepresented in the national toxicity data base.
The net result is that we now have a great deal of data about a few species, but little or no data about the vast majority of species. Nor do the data available necessarily represent a reasonable cross section, based on sensitivities or ecological importance. The above assertions will be supported using examples from the national data base and from data bases on individual chemicals. This indicates a need for information on a wider variety of organisms in order for the national data base to be representative of the full range of sensitivities expected in the population as a whole. While it is recognized that it will not be possible to conduct tests on all species, the underlying distribution of the data base should be understood before appropriate statistical methods can be developed to derive national water quality criteria for the protection of aquatic life. This may require some testing of representative species from sensitive and insensitive groups. Additional implications of the actual distribution of the national toxicity data base will be discussed.
Delamination Crack Growth in Composite Laminates
Authors: Wang ASD , Slomiana M , Bucinell RB 
Published: December 2008

This paper presents in detail the application of an energy method to describe a class of delamination crack growth problems found in polymer-based composite laminates. The energy method is derived from the general concepts of classical fracture mechanics. When used judiciously and with proper interpretation of the physical factors pertinent to the crack growth process at the lamina(ply) level, the method describes well delamination growth behavior in laminates that are subjected to monotonically (static) or cyclically(fatigue) applied loads or to both. Both could be in tension or in compression.
The basic method can be used to describe not only one-dimensional delamination growth (for example, free edge delamination) but also two-dimensional delamination growth (contoured delamination). Laboratory test results using laminates made of an AS-3501-06 graphite epoxy system are presented along with analytically predicted results. Excellent correlations between analytical and experimental results are obtained.
Static Behavior of Variably Cemented Beach Sands
Authors: Rad NS , Clough GW 
Published: December 2008

The surface of the seafloor is covered by sediments consisting of or containing calcareous, siliceous, or argillaceous soils. These sediments are frequently exposed by tectonic uplift or sea level lowering and usually exhibit a degree of cementation. In coastal areas and in a consolidated form they can stand at steep angles and in bluffs as high as 150 m. Although apparently strong, they tend to lose most, if not all, of their strength at the time of failure resulting in sudden and complete collapse.
This paper presents selected test results obtained during laboratory investigation concerning the effects of cementation on the behavior of soils. Utilizing block sampling techniques, naturally occurring cemented soils were sampled from the bluffs along the Pacific coast south of San Francisco, CA. The sands are of quaternary and tertiary marine origin and are classified as weakly or moderately cemented. Static strain-controlled drained and undrained triaxial tests were performed on samples confined under different pressures. Thin sections and electron micrographs were prepared to assess agents of cementation.
Ceramic Fracture Features, Observations, Mechanisms, and Uses
Authors: Rice RW 
Published: December 2008

The character and occurrence of mist, hackle, and crack-branching features on ceramic fractures are reviewed and possible mechanisms for causing these features are discussed. Besides glass and polycrystalline fractures, substantial attention is paid to fractures of ceramic crystals, for which new data are presented and similarities shown to fractures of brittle metal crystals. Distinct geometrical effects exhibited by crystal fracture features are illustrated and discussed, as are the variable distances from fracture origin to the onset of features such as mist.
Crack branching of ceramics, which is suggested to be the merging of hackle, is shown to follow the same type of relations as for the onset of mist and hackle. If there is rebranching, it tends to occur at multiples of the original branching distance. Substantial data (again much of it new) show that branch angles are similar for a wide variety of ceramics as well as for brittle fracture of metals. Branch directions are shown to depend on the nature of the test specimen (or crystal directions), and biaxial testing is shown to increase branch angles over those for uniaxial flexure of tension testing. Observations, mechanisms, and effects of intergranular versus transgranular fracture are discussed. The determination and character of flaws causing fracture are summarized, and questions concerning their behavior are raised (for example, effects of complex flaws and of mixed-mode failure).
Scanning Electron Microscopy Techniques and Their Application to Failure Analysis of Brittle Materials
Authors: Healey JT , Mecholsky JJ 
Published: December 2008

The applicability of scanning electron microscopy (SEM) to failure analysis of glasses, glass ceramics, and polycrystalline ceramic materials is presented. The principle electron operational modes include the secondary electron mode and the backscattered electron mode, where the traditional backscattered electron image obtained from a negatively biased Everhart-Thornley detector is compared with the topographical and compositional backscattered electron images obtained from the newer solid-state backscattered electron detectors. Both the energy-dispersive and wavelength-dispersive X-ray analysis modes and their relation to failure analysis are presented.
The principles of fracture mechanics are combined with the fracture surface analysis to illustrate the correlation between the fracture surface features and fracture mechanics. Examples of phase-separated glasses will show the ability to determine the propagation path with respect to the phase-separated regions. Glass ceramic fracture toughness samples will be used to illustrate the ability to observe the microstructure and fracture features independently using backscattered electron imaging techniques. Ceramic samples will be used to show the applicability of determining failure mode (transgranular versus intergranular) as well as interaction with twinning and second phases.
Analysis of Failures Associated with Intergranular Fracture
Authors: Pellegrino JV , McCartney RF 
Published: December 2008

Intergranular fracture is usually the most easily recognizable mode of fracture, but determining the cause may be quite difficult. Although fractography identifies the presence of intergranular fracture, a correlation of both fractographic and metallographic features should be obtained to aid in identifying the mechanism responsible.
Case histories of failure analyses in which intergranular fractures were observed and were attributed to a variety of mechanisms are presented and include (1) liquid-metal embrittlement of an AISI 1070 rod caused by copper pickup during processing, (2) liquid-metal embrittlement of a low-carbon steel caused by lithium in service, (3) liquid-metal embrittlement of a platinum and platinum-rhodium thermocouple caused by a low-melting platinum-silicon eutectic that formed in service, (4) fracture of a steel-strand wire-rope caused by an area of untempered martensite, (5) “rock candy” brittle fracture of a steel casting caused by the presence of aluminum nitride at the solidification grain boundaries, and (6) brittle fracture of heat-treated bolts manufactured from columbium-treated fine-grain AISI 1541 steel caused by the presence of a columbium film at prior-austenite grain boundaries.
The investigative techniques used included light microscopy, scanning electron microscopy, energy-dispersive spectroscopy, electron diffraction, and secondary-ion mass spectroscopy.
Swelling of Austenitic Iron-Nickel-Chromium Ternary Alloys During Fast Neutron Irradiation
Authors: Garner FA , Brager HR 
Published: December 2008

Swelling data are now available for 15 iron-nickel-chromium ternary alloys irradiated to exposures as high as 110 displacements per atom (dpa) in Experimental Breeder Reactor-II (EBR-II) between 400 and 650°C. These data confirm trends observed at lower exposure levels and extend the generality of earlier conclusions to cover a broader range of composition and temperature. It appears that all austenitic iron-nickel-chromium ternary alloys eventually approach an intrinsic swelling rate of ∼1%/dpa over a range of temperature even wider than studied in this experiment. The duration of the transient regime that precedes the attainment of this rate is quite sensitive to nickel and chromium content, however.
At nickel and chromium levels typical of 300 series steels, swelling does not saturate at engineering-relevant levels. However, there appears to be a tendency toward saturation that increases with declining temperature, increasing nickel and decreasing chromium levels.
Comparisons of these results are made with those of similar studies conducted with charged particles. Conclusions are then drawn concerning the validity of charged particle simulation studies to determine the compositional and temperature dependence of swelling.
Swelling of Microstructure of Neutron-Irradiated Titanium-Modified Type 316 Stainless Steel
Authors: Seran JL , Naour LL , Grosjean P , Hugon MP , Carteret Y , Maillard A 
Published: December 2008

The analysis of the behavior of fuel pins irradiated in the same Rapsodie subassembly, shows that titanium has a marked beneficial effect on the swelling resistance of cold-worked Type 316 stainless steel in a wide temperature range. This effect is particularly visible at high temperature since cold-worked Type 316 titanium does not swell above 550°C up to a dose of 100 French displacements per atom (dpaF)(∼74 dpa NRT).
The results obtained on samples irradiated in a Rapsodie experimental rig give us confirmation of the good behavior of cold-worked Type 316 titanium stainless steel that swells less and at lower temperature than other steels of the Type 316 series such as solution-annealed Type 316 titanium or aged solution-annealed Type 316 titanium.
The swelling differences between some of these materials can be associated with different microstructures that are also very different from the ones obtained on the unirradiated steels aged for the same time and temperature conditions.
Influence of Composition on Steady-State Void Nucleation in Irradiated Alloys
Authors: Esmailzadeh B , Kumar AS 
Published: December 2008

The major features of the compositional dependence of radiation-induced swelling of iron-nickel-chromium and iron-nickel-chromium-silicon alloy systems are reproduced using a model proposed by Garner. The model asserts that the major compositional dependence of radiation-induced swelling can be explained by the compositional dependence of the effective vacancy diffusion coefficient, Dveff. The primary influence of composition resides in the transient regime of swelling and is related to the effect of Dveff on the rate of void nucleation.
Measured variations in elemental diffusivities with composition and temperature are used along with the KWR nucleation theory to calculate the steady-state void nucleation rate. The nucleation rate is inversely proportional to the duration of the transient regime at any given temperature. Void nucleation rate is found to depend strongly on the silicon content, and to a lesser extent on the nickel and chromium contents.
Corrosion and Degradation of Implant Materials: Second Symposium
Authors: Fraker AC , Griffin CD 
Published: December 2008

Description
An update of STP 684. Details new studies in vitro and in vivo of metals, polymers, and ceramic materials used in surgical implants. Subjects include aneurysm clip materials, fatigue ball-joint rods, electrochemical studies of dental alloys, arc plasma sprayed coatings, biocompatibility, biodegradation, risk management, performance standards, regulation, and litigation.
Inhalation Toxicology of Air Pollution: Clinical Research Considerations
Authors: Frank R , O'Neil JJ , Utell MJ , Hackney JD , Van Ryzin J , Brubaker PE 
Published: December 2008

Description
Discusses issues critical to the design, execution, and analysis of basic and applied research. Divided into four sections: an overview of clinical research; measuring the response; subjects with underlying lung disease; and statistical and analytical considerations.
Skiing Trauma and Safety: Sixth International Symposium
Authors: Mote CD , Johnson RJ 
Published: December 2008

Description
Papers explain the factors resulting in ski injuries and the steps being taken to reduce the risk of ski injuries. Topics include: biomechanics and knee injuries; ski boots; release bindings, including testing; epidemiology of skiing injuries in Japan and Germany; spinal injuries; use of helicopter evacuation; and FIS efforts to control competitive skiing injuries.
Zirconium in the Nuclear Industry
Authors: Adamson RB , Van Swam LFP 
Published: December 2008

Description
Forty papers deal with properties of Zircaloy and to a lesser extent, Zr-2.5-Nb. The majority covers fabrication and physical properties, general corrosion and hydriding, fracture and fatigue, and stress corrosion cracking. Special consideration is given to irradiation growth, Zircaloy cladding behavior under conditions expected in a loss-of-coolant accident, and nodular corrosion.