bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of the Active Defect Complex in the Neutron Embrittlement and Thermal Recovery of High-Copper Reactor Pressure Vessel Steels
Authors: Highton JP 
Published: March 2009

Annealing studies of irradiated and unirradiated pressure vessel steel have led to the conclusion that an active defect complex (ADC) is responsible for the enhanced embrittlement associated with steels containing significant levels of copper (&gt;0.1%). These complexes, which already exist in the unirradiated steel, accumulate vacancies, produced either thermally or by neutron bombardment, and grow to such a size that the dislocation mobility is impaired and the yield stress increased. The number density of the sites appears to be a function of the copper level in the steel. Thus in low-copper steels the site spacing is too great to affect the yield stress.
The stable size of the complex seems to be an inverse function of temperature. Thus after preservice stress relief heat treatment the sites are too small to influence the mechanical properties of the vessel steel. At lower temperatures, however, exposure to a vacancy flux causes the sites to grow to their equilibrium size at a rate determined by both the availability of vacancies and the number density of the sites. Postirradiation annealing will cause the ADCs to shrink to a size that is stable at the annealing temperature. The ADCs also act as traps to positions and cause the line shape of the 511-keV annihilation peak to narrow. This effect appears to be related to the site size. Herein lies a prospect for remote interrogation of a reactor pressure vessel to assess the state of embrittlement resulting from this mechanism, both through life and after annealing.
Phase-Resolved Nanosecond Spectrofluorometry: Theory, Instrumentation, and New Applications of Multicomponent Analysis by Subnanosecond Fluorescence Lifetimes
Authors: Mattheis JR , Mitchell GW , Spencer RD 
Published: March 2009

We describe a new method, phase-resolved subnanosecond spectroscopy (PRS), for the spectral differentiation of fluorophores in a mixture. The technique required adding a phase-variable rectifying detector to the SLM 4800S phase-spectrofluorometer. The theory of PRS is based on the sinusoidal fluorescence emission of a population of molecules in response to sinusoidally modulated excitation light. The total a–c fluorescence signal is passed through the phase-variable detector which nulls the emission signal of any component in quadrature with the reference angle. The emission characteristics of the remaining component, or components, are more readily and accurately revealed. We investigated the sensitivity and selectivity of PRS. The sensitivity of PRS was demonstrated by nulling the contribution of the Raman scatter band of a nanomolar solution of quinine bisulfate to the real-time emission spectrum resolved at 8-nm bandpass. We demonstrated the selectivity of PRS by resolving the emission spectrum of anthracene and perylene from a 1 : 1 mixture with a lifetime differential of only 600 ps. Also, the emission spectra of 2,2-phenylene bis-(5-phenyloxazole) and dimethyl 2,2-phenylene bis-(5-phenyloxazole) were also resolved from a 1:1 mixture in ethanol. The lifetime differential here was only 200 ps.
We also applied the PRS technique to investigate the heterogeneous emission due to tyrosine and tryptophan residues in the protein bovine serum albumin (BSA). Suppression of the fluorescence emission of tryosine at 300 nm allowed us to resolve the emission spectrum of tryptophan. Suppression of the fluorescence emission of tryptophan at 400 nm allowed us to resolve the emission spectrum of tryosine. The PRS spectra of the two components suggested the presence of an additional species that may add to the heterogeneous emission of the protein.
Flow Rates of Guthion and Cottonseed Oil Mixtures
Authors: Barnett HG 
Published: March 2009

The use of cottonseed or soybean oil as a diluent is becoming increasingly important in ultralow-volume (ULV) application of pesticides. Guthion 2L is registered for ULV application, so it was of interest to study the variables that could affect the flow rates of Guthion 2L oil mixtures through various nozzle tips.
The tests were conducted with a carbon dioxide hand sprayer, with the viscosity, temperature, and pressure as variables.
The mixtures used were 0.235 to 0.47 L (½ to 1 pt) of Guthion 2L in 0.47 to 0.705 L (1 to 1 ½ pt) of cottonseed oil. In each evaluation, the total volume was ∼0.94 L (2 pt). The temperature ranged from 23.9 to 48.9°C (75 to 120°F) and the pressures from 206.8 to 275.8 kPa (30 to 40 psi). Nozzle tips Nos. 8002, 8003, and 8004 were used.
In summary, whenever the ratio of Guthion 2L to cottonseed oil was 1:1, the temperature and viscosity had little effect on the flow rate. If the ratio was changed to 0.235 L (½ pt) of Guthion 2L to 0.705 L (1 ½ pt) of cottonseed oil, there was a significant change in the flow rate through the nozzle tip in relation to the temperature. It appears from the data that a flowmeter may be a necessity to avoid application problems.
A Test Method to Determine the Degree of Embrittlement in Electrodeposited Copper
Authors: Zakraysek L 
Published: March 2009

The brittle fracture of copper conductors in printed circuits is a severe problem in the electronics industry because such fractures will cause open-circuit conditions to occur in completed assemblies where the contributed value is high. In addition, repair possibilities may be limited due to the complexity of the assembly at the time that failures are discovered.
This paper deals with the development of a test method that is useful for the detection of an embrittled condition in foil prior to its application in circuits. Through the use of the mini-cup test method, a ductile-to-brittle transition was discovered, and, through further study of the transition phenomenon, procedures have been suggested for the characterization of electroplated copper foil.
The Use of Fatigue Crack Growth Technology in Fracture Control Plans for Nuclear Components
Authors: Bamford WH , Jones DP 
Published: March 2009

The American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code now suggests the use of fatigue crack growth analysis in the evaluation of indications found during in-service inspection of nuclear components. In this paper the role of crack growth analysis in the evaluation process is reviewed in some detail, and the background and philosophy of its implementation is discussed.
Each of the steps in the crack growth analysis process is discussed in order to point out the assumptions possible and their implications. A detailed consideration of crack shape change during growth is presented, as well as a statement of guidelines for choosing a reference crack growth law.
The ASME approach is compared with the approaches taken in other industries and, finally, a number of areas in need of further work are highlighted.
Field Investigations and On-Site Toxicity Testing: An Assessment of Habitat Suitability—Arkansas River, Pueblo, Colorado
Authors: Keefe DF , Nimmo DWR , Baldridge D , Iley G 
Published: March 2009

An on-site bioassay and aquatic ecological survey were conducted on the Arkansas River near Pueblo, CO. A mobile bioassay trailer was used to test the toxicity of sewage treatment plant (STP) effluent using Arkansas River water for dilution. The aquatic survey was conducted upstream and downstream of the STP's outfall. This study was conceived in accordance with the intent of the U.S. Environmental Protection Agency's (EPA) site-specific water quality criteria guidelines, which recognize that national criteria may not be applicable to species in specific bodies of water because of biological, chemical, and physical variables.
Flow-through tests were conducted using bluegill sunfish (Lepomis macrochirus), fat-head minnow (Pimephales promelas), and a daphnid (Daphnia magna). Standard field and laboratory techniques were used to evaluate physical and biological components of the stream ecosystem. The physical components included flow, substrate, and qualitative fishery habitat description, and the biological components included benthic macroinvertebrate densities, diversity calculations, and fish population surveys.
The results of the bioassay tests generally indicated the following: (1) there were distinct differences in species'; sensitivity to the effluent (that is, the sensitivity was bluegills &gt; fathead minnows &gt; daphnid); (2) the required dissolved oxygen (DO) concentrations in the test tanks were difficult to maintain even though the flow-through rate was increased to four times that required by protocol; (3) the toxicity of the postchlorinated/dechlorinated effluent was less than that of the prechlorinated effluent; (4) no single pollutant could be targeted as the toxic fraction, however, concentrations of chlorine, cyanide, copper, and zinc were at or near LC50 values for the test organisms.
Toxicity of the Herbicide Endothall to Juvenile Chinook Salmon (Oncorhynchus tshawytscha)
Authors: Liguori VM , Zakour HR , Landolt ML , Felton SP 
Published: March 2009

Endothall (7-oxabicyclo-2,2,1-heptane-2,3-dicarboxylic acid) is a contact herbicide which has been approved by the U.S. Environmental Protection Agency (EPA) for use in programs aimed at controlling nuisance organisms such as Eurasian water milfoil (Myriophyllum spicatum). Milfoil has become such a problem in local freshwater systems that Seattle authorities have approved the use of endothall in circumstances in which other eradication methods are not effective. This study was performed to determine the toxicity of endothall to juvenile chinook salmon (Oncorhynchus tshawytscha) and the effects of the herbicide on the ability of this anadromous fish to enter seawater.Two 14-day flow-through toxicity tests were conducted using nominal concentrations of endothall ranging from 0 to 105.7 ppm of acid equivalent. Four-day toxicity tests were also conducted using the two lowest concentrations (1.5 and 3.0 ppm) to approximate the recommended treatment levels. Upon termination of the toxicity tests, the fish that had been exposed to a noeffect (no mortalities) concentration of the herbicide (≤55 ppm) were utilized in the seawater entry tests.The 14-day LC50 was calculated to be 62.5 ppm. The seawater entry test proved to be the more sensitive indicator of toxicity, as the fish that had been exposed to endothall levels as low as 3 ppm for four days died when placed in seawater. Survival of the control fish and the fish exposed to 1.5 ppm was acceptable, as was survival of all the fish transferred to clean fresh water. Some behavioral and gross anatomical changes were observed, and histopathological examination revealed hypertrophy of branchial epithelial cells in the fish exposed to 10 ppm or more of endothall.
Column Leach Testing of Solid Industrial Wastes
Authors: Darcel FC 
Published: March 2009

Column leach tests with distilled water have been used routinely over the past four years to assess the leachability of industrial wastes. Most tests are run using unsaturated flow condition with three cuts of leachate obtained over 24, 48, and 72 h. Leachate cuts are analyzed for concentrations of inorganic ions, phenols, dissolved organic carbon, conductivity, and pH. It is shown that in many situations ionic and organic flux over the three cuts follow the penetration theory of diffusivity. The relationship held over a wide range of types of waste and initial pollutant concentration. Some bag-house dusts and mine tailings were found to be highly leachable even with distilled water.
Some tests were run using distilled water saturated with carbon dioxide to provide weak acidic conditions. The water leach is followed by 0.1 N acetic acid to simulate the effect of co-disposal with municipal waste.
Some wastes were tested using the Extraction Procedure (EP) test of the U.S. Environmental Protection Agency (EPA).
Enhancement of Aflatoxin B1 Hepatocarcinogenesis in Rainbow Trout (Salmo gairdneri) Embryos by Prior Exposure of Gravid Females to Dietary Aroclor 1254
Authors: Hendricks JD , Stott WT , Putnam TP , Sinnhuber RO 
Published: March 2009

Gravid female rainbow trout were exposed to dietary Aroclor 1254 [polychlorinated biphenyl (PCB)] for 2 months before spawning in order to deposit PCB in the lipid of the eggs. Levels of PCB in the eggs were measured, effects of PCB on liver tumor incidence initiated by embryo exposure to aflatoxin B1 (AFB1) were noted, and hepatic mixed-function oxidase (MFO) enzyme activities were determined.
Gas chromatography showed that PCB was present in the lipids of the eggs at significantly higher levels than the background levels present in control eggs. Liver carcinoma incidence was significantly higher in the offspring from the PCB-exposed female at both 9 months (24 out of 40 versus 15 out of 40) (P &lt; 0.025) and 12 months (53 out of 57 versus 39 out of 59) (P &lt; 0.001), which indicates that preinduction of the liver by PCB enhances aflatoxin-initiated carcinogenesis. Mixed-function oxidase determinations also revealed trends that suggest induction of the MFO system by PCB. The cytochrome P-450 content in the PCB fry livers was 174 percent of the control values, whereas the in vitro conversion of AFB1 to aflatoxicol (AFL) was 264 percent of that of the control. These results call attention to the possible role of PCB in enhancing carcinogenesis.
On-Site Critical Life-Stage Bioassay with the Fathead Minnow, Pimephales promelas, on Effluent from the Wastewater Treatment Facilities of Austin, Minn.
Authors: Iwan GR , Cella GE 
Published: March 2009

An on-site, flow-through, critical life-stage bioassay was conducted challenging the fathead minnow with treated effluent from the City of Austin, Minn., wastewater treatment facilities. Using U.S. Environmental Protection Agency (EPA) methodology modified by Union Carbide Environmental Services (UCES) and the Minnesota Pollution Control Agency (MPCA), effluent effect data were obtained for (a) egg hatchability, (b) fry survival, (c) fry growth, and (d) fry deformities. The data were used to estimate the maximum acceptable effluent concentration (MAEC) range, expressed as percent effluent and ammonia concentration. Statistical analyses (P = 0.05) indicated an MAEC range of 18 to 32 percent treated effluent. The corresponding un-ionized and total ammonia concentrations were, respectively, 0.2 to 0.3 mg/litre and 2.3 to 3.2 mg/litre.
In light of the current EPA water quality criterion of 0.02 mg/litre un-ionized ammonia, the results suggest that in situ studies of this type might be useful in establishing more realistic discharge requirements.
Prediction of Ignition Thresholds During Ramp Heating
Authors: Martin SB 
Published: March 2009

This paper offers a heuristic, semiempirical approach to prediction of thresholds of spontaneous ignition of materials exposed to ascending heat ramps in terms of the dependence of the time taken to ignite ti on rates of change of heat flux with time. The approach relies on the concept that two conditions are necessary (if not always sufficient) for ignition to occur: (1) the exposing flux must first grow to exceed some critical level Hc, taken as equivalent to the so-called “critical irradiance” determined from constant-flux exposures; (2) the additional time for ignition to occur (ti − tc) is then a prescribable inverse function of the rate of flux increase (that is, the slope of the ramp). Temperature attainment criteria are employed in arriving at a mathematical formalism.
Data to test the approach are derived from a previous experimental study of quarter-scale room fires (propane fueled) in which wood block targets on the floor were observed to ignite spontaneously from exposure to heat radiated by the ceiling. Additional data, acquired specifically to extend the range of rates of flux growth and reported here for the first time, were obtained by exposing similar wood targets to ascending heat ramps produced manually with a tungsten-filament radiant heat source. The resultant data, from the two experimental sources, are reasonably well fit by a thermally thick-solid expression relating ti − tc to the rate of flux growth evaluated with independently derived empirical constants.
Factors Affecting Smoke Production During Combustion of Polyolefin Polymers
Authors: Sutker BJ 
Published: March 2009

Fire is only one of the major hazards that result from rapid combustion of polyolefins. Another major hazard is smoke evolution, since smoke can prevent people in a fire from finding necessary exits. Smoke, however, should not be considered independently from the composition of the smoke, that is, the products of combustion.
Olefin polymers are formulated with a variety of additives to meet specific performance characteristics. Smoke can be reduced by additives, but often at the expense of other properties of the system. Suggestions are made for further research activities to improve smoke reduction.
Test methods used to measure smoke are described and comparisons are made between materials in a given test sequence. Further research work is needed in the area of assessing smoke evolution as a function of time, particularly at the onset of a fire.
JR-Curve Testing of Large Compact Specimens
Authors: McCabe DE , Landes JD 
Published: March 2009

This paper describes experiences and special testing techniques applied to JR-curve development using compact specimens ranging in size by factors up to 20. All specimens were 20 percent side-grooved. The material used was A508 Class 2A and the tests were made at 477 K (400°F). Unloading compliance was used to measure crack growth and a special displacement measuring gage having high sensitivity and linearity was developed to detect minute compliance changes of the order of 0.1 percent. High-temperature creep effects were present but these were readily eliminated from interfering with unloading compliance precision by prior partial unloading to below the creep deformation range. Crack growth was calculated using a differential compliance formula and was usually predicted accurately within ±15 percent of the heat tint indicated growth. This was generally true over a wide range of specimen sizes and initial crack sizes.
An example JR-curve comparison is given, comparing small-specimen versus large-specimen data. Deviation from a common JR-curve develops when Δap ⩾ 0.06 b0, where b0 is the initial specimen ligament size. For the smallest specimen data, a modified J calculation was applied which reestablishes comparability between large- versus small-specimen JR data, and this can be maintained over crack growth that represents a substantial ligament size change.
Computer-Controlled Single-Specimen J-Test
Authors: Van Der Sluys WA , Futato RJ 
Published: March 2009

The development of a computer-controlled single-specimen J-test procedure is described. The results of a sensitivity study to determine the effect of analog-to-digital converter resolution and transducer signal noise on elastic unloading compliance crack length measurements are presented. The results are used to estimate the minimum equipment performance specifications needed for successful J-test automation. The actual test system is described along with the details of the automated procedure.
A comparison is made between results obtained using the automated procedure and the more conventional heat-tinting technique for HY-130 at room temperature (tested as part of the American Society for Testing and Materials J-Integral R-Curve Round Robin Program) and nuclear pressure vessel grade steels at 200 to 290°C. Good agreement in the generation of J-Δa data was found in all cases. However, some difficulty was encountered in predicting absolute crack lengths by compliance in the round-robin tests, apparently due to specimen design.
Studies of Different Criteria for Crack Growth Instability in Ductile Materials
Authors: Kaiser S , Carlsson AJ 
Published: March 2009

A general instability condition of solid mechanics, valid for a nonlinear structural component in an otherwise elastic system, is shown to be inherent in the T-modulus concept of instability. This condition involves the slope of the descending part of the load-displacement curve of the nonlinear component. It is shown that this slope can be used to evaluate T appl at instability; Tappl can then be used to give a simple estimation of Tmat without the need for exact crack length determination.
In this paper such evaluations for large panel specimens and smaller bend and CT specimens are reported for three structural steels. The obtained data are in good agreement with conventionally determined data. However T-evaluations for tension-type specimens give values which are higher by a factor of two than those calculated for bendtype specimens. This indicates that T is not geometry independent, but that T from bend and CT specimens gives a lower bound.
A method is discussed of analyzing the instability of a large structure with a cracked, ductile component using the slope of the load-displacement curve and the general instability criteria of mechanics without recourse to fracture parameters.
Micromechanisms of Ductile Stable Crack Growth in Nuclear Pressure Vessel Steels
Authors: Belcher WPA , Druce SG 
Published: March 2009

The objective of this work was to investigate the relationship between the micromechanisms of ductile crack growth, the microstructural constituent phases present in nuclear pressure vessel steel, and the observed fracture behavior as determined by impact and fracture mechanics tests.
Results from a microstructural and mechanical property comparison of an A508 Class 3 pressurized water reactor nozzle forging cutout and a 150-mm-thick A533B Class 1 plate are reported. The variation of upper-shelf toughness between the two steels and its orientation sensitivity are discussed on the basis of inclusion and precipitate distributions. Inclusion clusters in A533B, deformed to elongated disks in the rolling plane, have a profound effect on short transverse fracture properties.
Data derived using the multi-specimen J-integral method to characterize the initiation of ductile crack extension and resistance to stable crack growth are compared with equivalent Charpy results. Results of the JR-curve analyses indicate (1) that the A533B short transverse crack growth resistance is approximately half that observed from transverse and longitudinal specimen orientations, and (2) that the A508 initiation toughness and resistance to stable crack growth are insensitive to position through the forging wall, and are higher than exhibited by A533B at any orientation in the midthickness position.
Internal Damage to Optical Glasses with 3 ns-Pulse Laser
Authors: Hack H , Neuroth N 
Published: March 2009

The beam of a 3 ns pulse laser (1060 nm) is focussed with a convex lense with 1,1 m focal length. The glass sample to be tested is 20 mm thick: its rear surface has a distance of 100 mm from the focus. The part of the sample which will be shot is illuminated with a Xenon lamp and inspected with a microscope with four fold magnification before and after the shot. In each case a photo is taken.
Two types of internal damage are to be recognized: pointlike damage and threadlike damage. Some glass types show only pointlike damage, even at higher energies (applied energy densities up to 65 J/cm2); other glass types show only threadlike damage caused by self-focussing (dependent to the n2-value). In the most cases both damage types occur but at different levels of energy densities. In BK 1 and BK 7 glass no internal damage is to be seen when applying energy densities up to 65 J/cm2.