bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of Measurement Methods for Characterization of Porous Coatings
Authors: Hamman G 
Published: December 2008

A comparison was conducted of measurement techniques used to quantify porous coatings applied to implant surfaces for biological fixation. Four types of coatings were measured, which included two bead size ranges, one wire pad, and one plasma flame-sprayed coating.
The purpose of the study was to determine the relationships between the measurement techniques and their resultant values when compared using two-dimensional sections. Basic stereological principles were used in the approach to this study. An automated image analysis system was utilized in making the determinations. Pore size measurement was conducted using two methods: (1) a line intercept method with serial measurements conducted at multiple levels parallel to and in plane with the substrate surface and (2) an interactive user-defined region measurement, in which the evaluator determined which features within the structure constituted individual pores. Comparison of data from both measurement methods was made contrasting the line intercept with the user-defined measurements and the planar-section with the cross-section measurements. Average values for the percentage of porosity in each coating were compared. The values obtained on cross sections were compared with values obtained on planar sections; the results indicated that the volume fraction of porosity observed in the cross sections was reproducibly 5% higher than that measured in the planar sections.
In the pore size measurements, two measurement methods and two section planes were compared. The line intercept method data showed a general tendency toward a smaller pore size when compared with the user-defined pore size data. This trend was observed in the pore size measurements in both cross sections and planar sections. The automated line intercept measurement did not exclude minimum values; therefore, its population of very small intercepts appears to skew the average pore size toward a lower average.
The choice of measurement method and the section plane selection appear to have significant influence on the average values obtained when measuring pore sizes on two-dimensional specimens.
Protocol for Field Tests of Ultrasonic Devices for Rodent Management
Authors: Jackson WB , McCartney WC , Ashton AD 
Published: December 2008

Testing ultrasonic devices for rodent repellency in closed environments results in contradictory responses. Without alternative environments, such efficacy tests cannot approximate actual conditions, and can result in erroneous conclusions.
Conducting observations in actual rodent-infested environments provides the best circumstances in which to measure the efficacy of high-frequency sound as a rodent management tool. Ideally, the installation of ultrasonic devices should be the only environmental variable. Rodent activity, measured with tracking patches, food consumption, or motion monitors before and after activation of units, is correlated with sound pressure patterns in the environment. Both frequency and sound pressure are important parameters. Preferably, two on/off cycles should be used.
Interlaboratory and Intralaboratory Proficiency Testing
Authors: Horlick J 
Published: December 2008

Proficiency testing is an integral part of the NVLAP laboratory accreditation process. Demonstration of appropriate facilities, equipment, personnel, etc. is essential, but may not be sufficient for the evaluation of laboratory competence. Inter- and intralaboratory test data using special proficiency testing samples provide the accrediting authority with a way to determine the operational competence of the laboratory.
For many test methods, results from proficiency testing are good indicators of a laboratory's testing capability. Information obtained from proficiency testing helps to identify and lead to solutions to problems in a laboratory. If problems with the test method are suspected, information can be provided to the appropriate standards-writing bodies to use as a basis for improving the method.
Each field of testing and each specific test method within a field has unique proficiency testing requirements. Proficiency testing data should be analyzed by the accreditor in confidence and summary reports of the results sent to the participants.
A Fractographic Study of Damage Mechanisms in Short-Fiber Metal Matrix Composites
Authors: Allen DH , Harris CE , Nottorf EW , Wren GG 
Published: December 2008

A general constitutive theory is formulated for a short-fiber metal matrix composite. The constitutive theory is based on continuum mechanics with constraints provided by fracture mechanics and thermodynamics. The basic premise of the constitutive theory is that load-induced microstructural damage associated with the inclusion of the fibers in the metal matrix results in a loss of material stiffness.
The concept of the damage-dependent constitutive theory was evaluated by an experimental investigation of the microstructural damage in an Aluminum 6016-T6 matrix with silicon carbide (SiC) whiskers. The primary objective of the investigation was the identification of microstructural damage such as voids or cracks that were associated with the presence of the SiC whiskers.
The results of the experimental investigation include measured reductions in the elastic modulus of tension specimens which were loaded beyond yield and unloaded. Also, there was an associated change in the extent of the microstructural damage. These results lead to the conclusion that the effect of microstructural damage must be included in the constitutive relationship in order to fully describe the behavior of a metal matrix composite.
Fractographic Aspects of the Effect of Environment on the Fatigue Crack Propagation Mechanism in a High-Strength Aluminum Alloy
Authors: Ranganathan N , Bouchet B , Petit J 
Published: December 2008

Fatigue crack propagation tests were conducted in three different environments, air, vacuum, and high purity nitrogen (N2) [3 ppm water vapor (H2O) + 1 ppm oxygen (O2)], on a high-strength aluminum alloy, 2024-T351. From tests conducted at a load ratio of 0.5, a typical behavior in the N2 environment is brought into light. At moderate ΔK-values, the crack growth behavior in N2 is similar to that observed in vacuum. As ΔK decreases, the crack growth curve shifts towards the one obtained in air showing a progressive environmental effect occurring in the presence of traces of water vapor.
The fractographic observations for these tests show that the environmental effect observed in the crack growth curves is accompanied by changes in the fracture surface morphology.
The observed results are discussed considering an energy-based model and by taking into account a discontinuous crack growth mechanism at low growth rates.
J-Integral Toughness of Low Fluence Neutron-Irradiated Stainless Steel DIN 1.4948
Authors: De Vries MI 
Published: December 2008

Small compact-tension specimens of stainless steel German Industrial Standard (DIN) 1.4948, which is similar to American Iron and Steel Institute (AISI) Type 304, have been irradiated in the high flux reactor (HFR) at Petten up to a fluence level of 2 × 1024 n · m−2 (E &gt; 0.1 MeV) at 823 K. Post-irradiation J-integral toughness tests have been performed with constant displacement rates ranging over four decades from 10−8 to 10−4 m · s−1 at the irradiation temperature.
The test method is based on a combination of the multiple-specimen interrupted loading method with the direct current potential drop technique (DCPD) for continuous monitoring of the crack length. The J,R curves, obtained by this method, show good reproducibility, and consequently the scatter of the J-toughness parameters is small.
The irradiation caused modest reduction, by about 30%, of the characteristic J-toughness parameters J0,3 and dJ/da at the displacement rate of 2 × 10−6 m · s−1. Low toughness values were measured at the lowest applied displacement rate. Results from additional tests showed that the effect of (slow) prior-fatigue loading at the low frequency of 10−2 Hz is minor compared to the effects of the lower displacement rates.
Experimental Assessments of Notch Ductility and Tensile Strength of Stainless Steel Weldments After 120°C Neutron Irradiation
Authors: Hawthorne JR , Menke BH , Awadalla NG , O'Kula KR 
Published: December 2008

The Charpy-V (Cv) properties of American Iron and Steel Institute (AISI) 300 series stainless steel plate, weld, and weld heat-affected zone (HAZ) materials from commercial production weldments in 406-mm-diameter pipe (12.7-mm wall) were investigated in unirradiated and irradiated conditions. Weld and HAZ tensile properties were also assessed in the two conditions. The plates and weld filler wires represent different steel melts; the welds were produced using the multipass metal inert gas (MIG) process. Weldment properties in two test orientations were evaluated. Specimens were irradiated in a light water cooled and moderated reactor to 1 × 1020 n/cm2, E &gt; 0.1 MeV, using a controlled temperature assembly. Specimen tests were performed at 25 and 125°C.
The radiation-induced reductions in Cv energy absorption at 25°C were about 42% for the weld and the HAZ materials evaluated. A trend of energy increase with temperature was observed. The concomitant elevation in yield strength was about 53%. The increase in tensile strength in contrast was only 16%. The postirradiation yield strength of the axial test orientation in the pipe was less than that of the circumferential test orientation.
Results for the HAZ indicate that this component may be the weakest link in the weldment from a fracture resistance viewpoint.
Microstructural Characterization of Submerged Arc Weld Metals
Authors: Lawless KR , Pavinich WA , Lowe AL 
Published: December 2008

This paper presents the results of a detailed microstructural evaluation of Linde 80 submerged arc weld metals typically found in Babcock and Wilcox 177FA Class reactor vessels. Optical metallography was performed on Linde 80 weld metals to characterize the grain structure, and scanning electron microscopy (SEM) was used to characterize the fracture surfaces. These weld metals have a tempered bainitic structure with large amounts of manganese rich inclusions.
Analytical transmission electron microscopy (TEM) was used to characterize the carbides, coarse (0.1- to 2.0-μm) inclusions, and fine (2- to 50-nm) precipitates. Thin foil and extraction techniques were used to characterize particle morphology while convergent beam electron diffraction (CBED) and energy dispersive X-ray (EDS) techniques were carried out to identify the particle chemical composition and crystal structure. These results are compared with published results from simulated reactor vessel welds found in the in-situ annealing program sponsored by the Electric Power Research Institute (EPRI).
Irradiation Embrittlement of Advanced Pressure Vessel Steels
Authors: Sivaramakrishnan KS , Chatterjee S , Anantharaman S , Viswanathan UK , Balakrishnan KS , Roy PR 
Published: December 2008

Seven commercial steels in the form of plate, forging, or weldments supplied by Japan, France, and the Federal Republic of Germany to the International Atomic Energy Agency (IAEA) Co-ordinated Research Programme on “Analysis of the Behaviour of Advanced Reactor Pressure Vessel Steels under Neutron Irradiation” were irradiated at 290°C to a nominal fast fluence of 1 × 1019 n/cm2 (&gt;1 MeV) to evaluate the embrittlement sensitivity of these steels under neutron irradiation. These steels were basically of ASTM Types A533 and A508 (Unified Numbering System [UNI] K12521 and K13502) and their weldments, which had extra low copper and phosphorous contents. The copper and phosphorous contents in these individual steels varied from 0.01 to 0.07 wt% and 0.007 to 0.015 wt%, respectively. The nickel contents in these steels varied from 0.56 to 0.93 wt%.
The scope of this study was mainly to evaluate the changes in the notch ductility, tensile properties, and hardness as caused by fast neutron irradiation. This paper reports the results obtained on these advanced pressure vessel steels in the form of base metal, weldments, and weld heat affected zones. The results indicated that these advanced steels were practically insensitive to fast neutron induced embrittlement. The relative embrittlement of these steels were further analyzed to examine the contribution of nickel in presence of copper in causing embrittlement. The impact test results indicated that threshold amounts of 0.04-wt% copper and 0.7-wt% nickel would perhaps be required to cause relatively enhanced embrittlement in these steels, confirming thereby that nickel in presence of copper can cause enhanced fast neutron induced embrittlement.
Current Limitations of Trend Curve Analysis for the Prediction of Reactor PV Embrittlement
Authors: Gold R , McElroy WN 
Published: December 2008

In operating light water reactor (LWR) commercial power plants, neutron radiation induces embrittlement of the pressure vessel (PV) and its support structures. As a consequence, LWR-PV integrity is a primary safety consideration. LWR-PV integrity is a significant economic consideration, since the PV and its support structures are nonreplaceable power plant components and embrittlement of these components can, therefore, limit the effective operating lifetime of the plant.
To define the effects of neutron radiation damage on LWR pressure-temperature operating limits and to assess fracture toughness of power reactor PV, trend curves for the prediction of PV embrittlement have been developed. These trend curves are very general PV embrittlement curves that are used to evaluate current PV status as well as to predict the future state of the PV. In such trend curves, the two main measures of radiation damage are the adjusted reference nil-ductility temperature ARTNDT(RTNDT initial + ΔRTNDT) and the decrease in upper-shelf energy level determined from Charpy V notch impact tests. Current measures of neutron exposure most commonly used in trend curve analyses are fluence &gt;1 MeV and displacements per atom (dpa) in iron.
Since trend curves play such a crucial role in the assessment of PV embrittlement of operating commercial LWR power plants, a critical appraisal of trend curve analysis is essential. To this end, current limitations in trend curve analysis for the prediction of reactor PV embrittlement are examined. It is concluded that a number of systematic effects can arise because environmental differences exist between test reactors, surveillance capsule locations, and the actual irradiation conditions that accure within the PV of an operating LWR commercial power plant. An irradiation test program is advanced to investigate these systematic effects and to produce the requisite data needed to correct for such systematic biases in trend curve analysis.
Hydrogen Control in the Handling, Shipping, and Storage of Wet Radioactive Waste
Authors: Henrie JO , Flesher DJ 
Published: December 2008

Under contract with the Department of Energy, Rockwell Hanford Operations (Rockwell) conducted a series of studies related to Three Mile Island (TMI) post loss of coolant accident (LOCA) waste handling safety. The key factor in these studies was the control of radiolytic gases, specifically hydrogen and oxygen.
Success was achieved in the prediction of gas generation rates and in the development and application of gas control technologies. That success led to the publication of a “lessons learned” document, providing (1) a step-by-step guide in evaluating potential radiolysis hazards in waste storage and shipment activities and (2) a set of corrective options for preventing or controlling the hazards. The evaluation steps developed in the document are outlined in a functional logic diagram. Several procedures are described which provide safe and effective controls for hydrogen and oxygen levels in containers scheduled for shipment or interim storage. A method is provided to pre-evaluate each control option and select the most cost effective procedure for each case.
Operating Experience at the Los Alamos Spallation Radiation Effects Facility at LAMPF
Authors: Sommer WF , Lohmann W , Graf K , Taylor IK , Chavez RM 
Published: December 2008

Operation of a new irradiation facility at the beam stop (Target Station A-6) at the Clinton P. Anderson Los Alamos Meson Physics Facility (LAMPF) began in May 1985. The facility is now fully operational. A closed-loop water system, a closed-loop helium system, remote handling procedures for activated materials, experiment change-out procedures, and experiment control equipment are all in place.
Experience dictated a change in irradiation capsules from a system that used metal seals to a system that is completely welded. The seals were found to be unreliable and difficult to replace by remote means.
Several materials have been irradiated in the direct 760-MeV proton beam. Material property changes as well as helium production in a variety of materials are being investigated.
A special sample holder that can accommodate transmission electron microscopy (TEM) specimens, isolate them from the cooling medium, maintain fixed temperature, and retain essentially a stressfree state has been developed. Remote handling retrieval of these specimens is being developed.
Activation foil measurements are being made to determine the secondary particle flux and spectrum (charged particles and neutrons) that result from interaction of the direct proton beam with targets at the beam stop. Twelve independent irradiation ports, each with an irradiation volume of 0.12 by 0.25 by 0.50 m, are available for exposing material to this particle flux, primarily neutrons. Two irradiations were completed in this area during the period May through December 1985. The neutron spectrum here resembles a fission spectrum with the addition of neutrons in the MeV energy range (high-energy tail). The maximum neutron flux is about 6 × 1017 n/m2 s at one of the 12 ports and drops by a factor of about 10 as a minimum at another of the 12 ports.
Three independent ports for proton irradiations are in place. Each has an irradiation volume of about 150 cm3. The proton beam has a Gaussian intensity profile; the maximum proton flux at the center of the beam is 1.2 × 1014 protons/cm2 · s. The beam spot has a diameter of approximately 5 cm at 2σ. Four irradiations were completed in this area during the period May through December 1985.
Indoor Air Quality Measurements
Authors: Fortmann RC , Nagda NL , Koontz MD 
Published: December 2008

Measurements of contaminants and other parameters in indoor environments present unique challenges to researchers because of the variety of building types to be monitored, the presence of occupants, the large number of potential contaminant sources, and the high degree of temporal and spatial variation of contaminant concentrations.
Selection of monitors and sampling methods for indoor air quality monitoring requires careful consideration of numerous factors. Considerations related to the design of the indoor monitoring program as well as factors related to monitor and sampler performance must be evaluated. Practical considerations related to sampling in occupied environments play an important role in the selection of measurement devices.
This paper discusses general concepts that should be considered in the selection of instrumentation for monitoring indoor air quality. Specific instrumentation and methods are not reviewed, but examples of instrumentation and monitoring approaches are provided for researchers unfamiliar with indoor air quality monitoring.
Parts-Per-Billion Gaseous Mixtures: A New Challenge
Authors: Denyszyn RB , Sassaman T 
Published: December 2008

Specialty gas manufacturers are being driven by regulatory requirements to manufacture low concentration gaseous mixtures of various air pollutants. This paper describes some of the basic difficulties incurred in preparing parts-per-billion (ppb) concentrations of various volatile organics such as pyridine, Freon® 113, Freon® 114, vinylidene chloride, toluene, 1,4 dioxane, acetone, chlorobenzene, acetonitrile, and methylethyl ketone. Concentrations range from 10 to 150 ppb. During the manufacturing and certification of these mixtures, several problems were encountered, including:
1. Ghost peaks due to gas chromatographic system background.
2. Adsorption of compounds in the analytical system as well as on cylinder walls.
3. Difficulties in preparation of primary standards for calibration.
4. Contamination of cylinders, even after special cleaning and preparation.
It is therefore imperative that when purchasing such mixtures, a certificate of analysis as well as a copy of the chromatographs be provided to the user.
Recent Developments in the Sampling and Analysis of Isocyanates in Air
Authors: Dharmarajan V , Lingg RD , Booth KS , Hackathorn DR 
Published: December 2008

In the past decade (1975 to 1985) there has been a considerable amount of research activity in the field of sampling and analysis of isocyanates in air. The general trend has been to move away from impinger sampling to solid sorbent or coated filter techniques or both, and the method of analysis has shifted from spectrophotometric to chromatographic techniques.
Dynamic atmospheres of various isocyanates were generated in the laboratory and several sampling and analysis methods for isocyanates were evaluated. The sampling media tested include impingers containing p-nitrobenzyl propylamine (nitroreagent) and Marcali solutions, nitroreagent coated glasswool and glassifiber filters coated with nitroreagent, 1-(2-pyridyl)piperazine (PP), and sulfuric acid. The particle size distribution of the 4,41 diphenylmethane diisocyanate (MDI) atmosphere was also determined.
The studies show that isocyanates having significant vapor pressure such as toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), and phenyl isocyanate (PI), are usually present as a vapor in the ambient atmosphere and generally the impinger, the solid sorbent, and the coated filter methods sample them efficiently. However, it has been found in the laboratory generated airborne atmospheres of nonvolatile isocyanates such as MDI and 4,4′ dicyclohexylmethane diisocyanate (Des W or hydrogenated MDI) that the coated filter methods have better collection efficiency than the impingers. Nevertheless, a study from a Swedish team has found quite the opposite results in the field for MDI. In an MDI based polyurethane insulation spraying operation, the impingers collected more than the coated filters in simultaneous sampling.
This paper summarizes our evaluations of the various methods for the sampling and analysis of isocyanates and propose a hypothesis to explain the apparently contradictory finding of the collection efficiency of the filter and impinger method for MDI in the laboratory-generated atmosphere and in the field.
Damage Aspects of Ingot-to-Wafer Processing
Authors: Dyer LD 
Published: December 2008

Intensive efforts have been put into the growth of silicon crystals to suit today's solar cell and integrated circuit requirements. Each step of processing the crystal must also receive concentrated attention to preserve the grown-in perfection and to provide a suitable device-ready wafer at reasonable cost.
A comparison is made between solar cell and I.C. requirements on the mechanical processing of silicon from ingot to wafer. Specific defects are described that can ruin wafers or can possibly lead to device degradation. These include grinding cracks, saw exit chips, crow's-foot fractures, edge cracks, and handling scratches.