bluuebunny/crossref_metadata_2025 huggingface dataset:
Diagnosis of Building Condition by Neutron-Gamma Ray Technique
Authors: Livingston RA , Evans LG , Taylor TH , Trombka JI
Published: December 2008

This paper describes a technique for nondestructive, in situ analysis of building condition that involves the use of neutrons from a portable source and the detection of the gamma rays resulting from the interactions of the neutrons with the building materials. Applications of this technique include the mapping of salt and moisture profiles within the walls and the location of voids or inclusions.

The technique uses a californium-252 neutron source (106 N/s) for composition measurements and a cesium-137 gamma-ray source for density measurements and energy calibration. Emitted gamma rays are measured with a high-purity germanium detector. The intensity of discrete gamma-ray lines is a function of the concentrations of the various elements encountered within the wall by the neutron flux. Using characteristic gammaray energy signatures for materials of interest, a measured gamma-ray spectra can be processed to yield information on the relative elemental distribution of a variety of substances, including water, salt, and building materials such as limestone, brick, and iron reinforcing bars.

Applications of this technique to several common problems of building diagnosis are discussed, including the case of an 18th-century building at Colonial Williamsburg suffering from salt damage.
Prediction of Reference Transition Temperature Increase Due to Neutron Irradiation Exposure
Authors: Maricchiolo C , Milella PP , Pini A
Published: December 2008

A new approach of radiation damage data reduction is presented. The approach, called Constant Chemistry Analysis (CCA), is based on the systematic analysis of radiation damage observed on groups of steels having practically the same chemistry, in terms of copper and nickel content, individually considered.

For each group, a chemistry factor (CF) and exponent describing the reference transition temperature shift (ΔRTNDT) trend versus fluence has been inferred.

Finally, a prediction formula for the overall trend is derived bestfitting the chemistry factors and the exponents previously determined. This particular approach emphasizes the role played by copper and nickel on the build-up of radiation damage.

The major finding is that saturation may take place in steels with very high copper/nickel ratio after great damage in the early stage (low fluence).

Furthermore, nickel seems to not contribute in an adverse manner to the radiation damage but it rather helps to reduce the ΔRTNDT up to a content of about 1.0% over which it starts to develop an independent negative effect.

The steels considered in the analysis are A533 and A508 irradiated in test reactors in the United States, Germany, Japan, France, and Sweden with a copper and nickel content spanning from 0.02% to 0.22% and from 0.5% to 1.4%, respectively. The fluence (E > 1 MeV) was ranging from 1 × 1019 n/cm2 to 9 × 1019 n/cm2.
Basis for Revision 2 of the U. S. Nuclear Regulatory Commission's Regulatory Guide 1.99
Authors: Randall PN
Published: December 2008

Regulatory Guide 1.99, “Radiation Damage to Reactor Vessel Materials,” is being updated to reflect recent studies of the physical basis for neutron radiation damage and efforts to correlate damage to chemical composition and fluence. Revision 2 of the Guide contains several significant changes. Welds and base metal are treated separately. Nickel content is added as a variable and phosphorus removed. The exponent in the fluence factor is reduced, especially at high fluences. And, guidance is given for calculating attenuation of damage through the vessel wall. This paper describes the basis for these changes in the Guide.
Microanalytical Studies of Pressure Vessel Weld Materials
Authors: English CA
Published: December 2008

In this paper, the results from microanalytical studies of four quenched, tempered, and stress-relieved A533 B welds are reported. Emphasis has been placed on determining the micro-distribution of copper and nickel; elements known to cause or enhance irradiation embrittlement of pressure vessel steels. Copper contents varied from 0.15 to 0.6% by weight and both high (1.6%) and low nickel (0.1%) welds were examined. Specimens have been studied using transmission electron microscope (TEM) techniques whereby chemical information can be acquired of the scale of ≥ 10 nm. In the high copper welds, copper precipitation was observed on both grain boundaries and dislocations. However, the form and extent of the precipitation has been found to be affected by the nickel level. Preliminary results from unirradiated welds on the composition of small regions (10 by 10 by 100 nm) of the ferrite, free of second-phase particles, indicate the following. First, the manganese levels in all materials and the nickel levels in the high nickel welds were in good agreement with the bulk levels. Second, in the high copper welds, the levels of copper were significantly lower than the bulk (0.5 to 0.6% by weight) and were influenced by heat treatment. The last aspect to be reported is the observation of copper sulfide particles in all the welds studied, particularly in association with large manganese silicate inclusions. The implications of this work to the irradiation embrittlement phenomenon are discussed.
Annealing and Reirradiation Response of Irradiated Pressure Vessel Steels
Authors: Lott RG , Mager TR , Shogan RP , Yanichko SE
Published: December 2008

This paper summarizes the results of a series of tests on irradiated, annealed, and reirradiated welds performed to provide a data base for annealing a reactor pressure vessel. Specimens from three test welds were irradiated to neutron fluences of 8 × 1018 n/cm2 and 1.5 × 1019 n/cm2 (E > 1 MeV) with most of the high-fluence specimens receiving an intermediate anneal. Anneals were performed at temperatures ranging from 340 to 454°C with the primary emphasis placed on one-week anneals. Partial recovery of the yield stress, Charpy transition temperature, Charpy upper-shelf energy, and upper-shelf fracture toughness (JIc) was noted after annealing at all temperatures. The least recovery was observed in the upper-shelf fracture toughness. In sharp contrast, the Charpy upper shelf was fully recovered after the 454°C, one-week anneals.

The increases in the yield stress and the Charpy transition temperature during the second cycle of irradiation were significantly smaller than the increases in the first cycle. The increase in these properties during the second cycle was only marginally larger than the increase in the irradiated but not annealed materials. These results indicate that the beneficial effects of annealing on the Charpy transition temperature are maintained during reirradiation.

A model of irradiation embrittlement and annealing based on copper precipitate coarsening is described. It has been previously demonstrated that a primary cause of embrittlement in these steels is the formation of small copper precipitates. The coarsening of the precipitate structure during annealing would produce a stable structure, which would cause a recovery of mechanical properties and not be subject to large embrittlement rate on reirradiation.
Evaluation of the Use of Community Similarity Techniques As Applied to Phytoplankton Communities
Authors: Reinke DC
Published: December 2008

Seven community similarity indices were compared using a manipulated data set with known changes and an experimental data set of phytoplankton community data. Community similarities were calculated based on (1) strict number of individuals per species and (2) corrected for species size with an estimate of total biomass. The similarity techniques used in this study were heavily affected by the abundant species, and changes in the minor taxa were frequently undetectable. Two of the seven statistics were previously unpublished modifications of the Percent Similarity method of Whittaker [1], which were specifically modified to enhance the sensitivity to changes in low frequency species and proportional changes.

While complex numerical techniques are commonplace in ecological literature, there is no generally accepted mathematical definition of community similarity. Ideally community comparison techniques should be sensitive to the loss or gain of a species and to changes in abundance of low and high frequency taxa. They should also detect proportional changes. None of the community similarity techniques used in this study fulfilled all the above requirements completely. All the similarity techniques assigned similarity values based on the presence of individuals. Perfect replication of cell counts for scarce species added little or nothing to the similarity values. At this time, a combination of statistical techniques using both numbers per taxa and an estimate of total biomass per taxa is recommended for the analysis of phytoplankton community data.
Some Methods for Measuring Effects of Toxicants on Laboratory- and Field-Colonized Estuarine Benthic Communities
Authors: Tagatz ME
Published: December 2008

Effects of toxicants on estuarine macrobenthic animals that developed in sand-filled boxes in the laboratory and field during eight weeks were determined by comparing community structures in control boxes and in boxes treated with a toxicant. Boxes were colonized in the laboratory by planktonic larvae in continuously supplied unfiltered seawater and in the field by animals that occurred naturally. Field boxes were placed in estuarine waters, either near the laboratory or at salt-marsh sites subjected to contamination by mosquito control pesticide applications. Eight separate studies were conducted using the same test materials in laboratory and field tests. Communities that developed were diverse and averaged 1441 individuals, 30 species, and 6 phyla for laboratory tests and 933 individuals, 51 species, and 8 phyla for field tests. Toxicants were introduced via water, air, or sediment and before, during, or after colonization. Tests with laboratory- and field-colonized communities provided corroborating data as well as data unique to each test. Various structural attributes among laboratory, experimental field, and natural field communities were similar, indicating that data derived from the laboratory and field toxicity tests can have good environmental applicability.
Comparison of Estimates of Hazard Derived at Three Levels of Complexity
Authors: Niederlehner BR , Pratt JR , Buikema AL , Cairns J
Published: December 2008

Cadmium concentrations constituting a threat to aquatic ecosystems were predicted from data collected at two levels of biological hierarchy. A population-level estimate was derived from single-species toxicity test data, and a community-level estimate was derived from toxicity tests on protozoan communities. Estimates were compared with each other and with an ecosystem-level estimate derived from reports of ecological health and ambient cadmium levels in rivers, lakes, and streams.

Estimates of permissible acute concentrations differed by an order of magnitude. Single-species toxicity test data suggested that 42 μg Cd/L would affect 5% of taxa. The corresponding estimate from the community-level test was 459 μg Cd/L. Similar estimates of permissible chronic concentrations were not significantly different (0.82 and 0.20 μg Cd/L, single-species and community-level tests, respectively). Both estimates of permissible chronic concentrations fell within a rational range, the minimum defined by median cadmium concentrations in healthy aquatic systems (0.05 μg Cd/L) and the maximum defined by median cadmium concentrations in damaged systems (9.2 μg Cd/L).
Community-Level Effects of Coyote Population Reduction
Authors: Schmidt RH
Published: December 2008

Predator control in the United States is directed primarily at the coyote (Canis latrans). Control programs are constructed to relieve predation losses to livestock. Although a variety of nonlethal control techniques are being used to some degree, lethal control methods continue to be a major part of modern predator control programs.

Toxicants have played a major role in past coyote population reduction programs. Traditional toxicants included strychnine, thallium sulfate, sodium cyanide, and sodium fluoroacetate (compound 1080). The use of toxicants on federal lands was banned by presidential order in 1972; this ban was revoked in 1982. Toxicants may play a larger role in predator control programs if the U.S. Environmental Protection Agency approves registration of any old or new materials for that purpose.

There appears to be an inverse relationship between population levels of coyotes and red foxes (Vulpes vulpes), gray wolves (C. lupus), or other carnivores. When large-scale coyote population reduction programs were successful, red foxes and other medium and large mammalian predators tended to increase. Experimental work and observations on coyote and red fox interactions have shown that coyotes exclude foxes from coyote-occupied habitats. Thus a single-species population reduction program, with toxicants or other means, impacts other members of the medium and large mammalian carnivore guild. The resulting change may impact prey species, because of species-specific prey preferences and foraging tactics, but this is poorly documented.

This paper reviews historical trends of populations of North American canids and recent work on interspecific interactions of canids. In addition, it examines three ecological mechanisms that may be major factors leading to canid competition.
Preliminary Results of Interlaboratory Testing of a Standardized Aquatic Microcosm
Authors: Taub FB , Kindig AC , Conquest LL
Published: December 2008

Four standardized aquatic microcosm (SAM) experiments were performed at two laboratories to test the reproducibility of controls and copper sulfate treatments. Each laboratory (University of Washington and Duluth-EPA) conducted two 63-day experiments consisting of six replicates each of 0 (control), 500, 1000, and 2000 μg L−1 nominal copper (24 microcosms total). In controls, nitrate was rapidly converted to algal biomass and subsequently to Daphnia. Increasing amounts of copper delayed this conversion. At 500 μg L−1 Cu, algal blooms consistently occurred during the absence of Daphnia. Slightly different amounts of initial copper were related to the duration of these delays. Recovery of the microcosm communities was made possible by detoxification of copper through precipitation, chelation, and sorption, as predicted by the MINEQL copper speciation model. Statistical evaluation of results within each experiment was displayed by an “interval of nonsignificant difference” around the control means. A procedure to statistically compare experiments for reproducibility is being developed, based upon discriminant analysis of distance measures between control and treatment microcosms.

Results from this statistical procedure are presented for the four experiments on three variables (nitrate, Daphnia, algal biovolume). Statistical analyses support the hypothesis that these moderately complex ecological experiments are more similar within laboratories than between laboratories. In spite of this, the conclusions reached from both sets of experiments are similar.
A Microcosm Procedure for Determining Safe Levels of Chemical Exposure in Shallow-Water Communities
Authors: Giddings JM
Published: December 2008

This paper describes a method for determining safe levels of chemical exposure in shallow-water communities, using laboratory microcosms as test subjects. The safe level is considered to be the maximum exposure that causes no persistent, ecologically significant changes in the ecosystem. Shallow freshwater communities in ponds, lakes, and rivers are good experimental subjects for research on contaminants, and environmental toxicologists have measured their responses to a variety of chemicals. Certain patterns of community effects have been observed, including a decline in net primary production or the production: respiration ratio, concomitant changes in water chemistry, and changes in community composition brought about by interactions among sensitive and resistant populations. The same patterns can be reproduced in microcosms containing natural sediment, water, and communities of submersed aquatic plants (macrophytes). In experiments completed at Oak Ridge National Laboratory, microcosm-derived estimates of safe exposure levels were confirmed using outdoor artificial ponds, suggesting that the microcosm procedure can be an efficient and economical means of determining safe levels for shallow-water communities.

Details of microcosm construction, techniques for monitoring ecological variables in microcosms, and an experimental design for determining safe exposure levels are provided here. The microcosms are assembled by transferring components of natural ecosystems to 80-L aquaria in a controlled laboratory environment. The communities that develop in these systems are typically dominated by common, cosmopolitan littoral species of macrophytes, algae, and invertebrates. Methods are described for measuring changes in water chemistry, phytoplankton, periphyton, macrophytes, zooplankton, and ecosystem production and respiration. By monitoring these variables over a gradient of pollutant exposure levels, the safe level can be determined accurately and precisely.
Zooplankton Community Responses to Synthetic Oil Exposure
Authors: Hook LA , Franco PJ , Giddings JM
Published: December 2008

While direct toxicant effects on populations can be estimated from single-species bioassay results, the complete range of population and community responses can best be investigated at the ecosystem level. The objectives of this research were (1) to determine the effects of a contaminant (a coal-derived light distillate oil) on the zooplankton communities of laboratory pond microcosms and outdoor experimental ponds, (2) to compare responses of microcosm and field zooplankton communities with each other and with laboratory bioassay data, and (3) to explore the use of community structure data for impact detection.

The responses of the microcosm and pond zooplankton communities to oil treatment were quite similar. Their close agreement lends support for using shallow-water pond microcosms as surrogates for field experiments in hazard evaluation. Changes in cladoceran densities were the most sensitive indicators of stress in the zooplankton communities. Copepods were slightly less sensitive, and rotifers were least sensitive to oil treatment. Indirect effects on populations were observed at intermediate treatment levels. The lowest treatment levels at which persistent and significant ecological changes occurred were the same in both systems. These levels were similar to the lowest observed-effect concentration (LOEC) for the Daphnia magna chronic bioassy, or approximately 3% of the D. magna 48-h LC50.

Community structure responses were generally consistent between systems; however, sensitivity for detecting oil treatment effects varied greatly among the measures of community structure. Species richness and diversity measures were not as sensitive as individual species responses. Cluster and multivariate post-clustering analyses of community similarity values reflected indirect effects and had sufficient sensitivity to allow early impact detection. An expanded principal components technique, which used both zooplankton and water quality data, was also relatively sensitive and would be applicable for routine monitoring.
Production of Coexisting Juvenile Coho Salmon and Steelhead Trout in Heated Model Stream Communities
Authors: Hughes RM , Davis GE
Published: December 2008

A 4°C temperature differential was maintained between two model streams. Steelhead trout (Salmo gairdneri) were introduced as embryos and retained for one year. The following year, steelhead and coho salmon (Oncorhynchus kisutch) were introduced as embryos and retained together. Macroinvertebrates and fish were sampled every three weeks. Primary production and respiration were estimated seasonally.

Prey biomass and diversity, and the production, biomass, and numbers of steelhead and coho were generally lower in the heated stream than in the control stream. Production, biomass, and numbers of steelhead were lower than those of coho and lower when coho were present than when they were absent. It was concluded (1) that moderate temperature elevation can decrease the productivity of streams for steelhead and coho when food is limited, (2) that coho might reduce the productivity of streams for steelhead more than temperature elevation might, and (3) that model stream results are more likely to corroborate single-species bioassays of fish fed limited rations than of fish fed to repletion.
Use of an Upflow Column Leaching Test to Study the Release Patterns of Heavy Metals from Stabilized/Solidified Heavy Metal Sludges
Authors: Brown TM , Bishop PL , Gress DL
Published: December 2008

Stabilization/solidification of hazardous liquids and sludges with portland cement has been investigated as a method of treatment that will bind hazardous materials in a form that minimizes adverse effects on the environment after landfilling. Research has been conducted to determine the long-term acceptability of this technique for disposal of heavy metal sludges by determining the rate of release of metals from solidified/stabilized wastes. The primary concern of this research was to determine the manner in which the heavy metals are released from the paste, as this will be important in extrapolation of the short-term leaching test results to long time periods. These studies utilized upflow leaching columns to determine the effects of acid flux (meq/g/day) and waste particle size on the release of metals from the solidified cement paste containing heavy metal sludges. Two particle size ranges and two acid fluxes were evaluated. Leachates from the column were collected on a daily basis and analyzed for pH, alkalinity, cadmium, chromium, and lead. Release patterns were modelled successfully using a diffusion-based equation. An effective diffusion coefficient and leachability index were calculated for each combination of heavy metal, particle size, and acid flux. These values can be used to predict metal release rates.
Leachate Migration Through Clay Below a Domestic Waste Landfill, Sarnia, Ontario, Canada: Chemical Interpretation and Modelling Philosophies
Authors: Quigley RM , Rowe RK
Published: December 2008

The results of field and laboratory investigations of a domestic waste landfill overlying 30 m of natural clay are presented. Four study phases extending over a ten-year period will be summarized.

Concentration profiles for several soluble constituents (sodium, potassium, calcium, magnesium, Cl− and dissolved organic carbon) show migration to a maximum depth of ∼1.5 m in 15 years. this compares to an advective or seepage advance estimated to be only 3 to 5 cm, indicating migration primarily by diffusion. Concentration profiles for the heavy metals (iron, lead, zinc, and copper) indicate rapid field attenuation with migration to only 10 cm in the carbonate-rich clayey soil.

Graphed solutions to the coupled advection/diffusion equation using constant values for C0+ D, and Vs are only partially successful in predicting the observed chemical profiles because of apparent chemical partitioning at the waste/clay interface. A better fit is obtained by employing an artificial “effective” interface about 25 cm above the observed interface; however, this does not resolve the interface problems.

Recently, new analytical and numerical procedures have been developed for modelling this and other contaminant migration problems. These techniques automatically take into account time-dependent concentration variations within the landfill (for example, because of mass transport into the soil) and allow for a sharp drop in concentration because of surface effects (such as surface smear, drying, and interface partitioning). The numerical solution allows consideration of the effects of a thin but finite interface layer with properties different from those of the underlying soil. Both of these techniques are used in the field case resulting in much superior predictions than earlier models.

Comments are presented on the significance of this work relative to chemical fluxes through thin clay liners.
Low-Cost Data Management for Protection of Ground-Water Resources: The Importance of Quality Assurance
Authors: De Ville WB , Malloy JA
Published: December 2008

U.S. environmental regulations require the collection, statistical evaluation, and reporting of data associated with ground-water monitoring at hazardous waste facilities. Desktop personal computers are capable of managing the large volume of data and automatically generating the required reports. A functional data base for ground-water monitoring data has been developed for the Apple II personal computer. Design emphasis was placed on error-checking during data entry and on simplicity and consistency of all operations available to the user. This should be considered an integral part of quality assurance/quality control considerations, not only throughout the operations of sampling and chemical and physical measurements, but also throughout all operations involving data entry, storage, manipulation, and reporting.

The programming language used in data base development (a structured BASIC) was chosen to facilitate testing and debugging of program modules. A major design objective was to assure that all operations involved in entry, storage, manipulation, and statistical evaluation of data are well-documented and “bug-free.”
Sorption Kinetics of Competing Organic Substances on New Jersey Coastal Plain Aquifer Solids
Authors: Uchrin CG , Katz J
Published: December 2008

Batch rate and equilibrium experiments were conducted to examine the sorption characteristics of a mixed solute system consisting of para-dichlorobenzene (p-DCB) and 2,4-dichlorophenol (2,4-DCP) to solids from two New Jersey coastal plain aquifer systems. Results were compared to previously reported results obtained for single solute systems. The p-DCB effected a slight enhancement on the 2,4-DCP sorption to the Potomac-Raritan-Magothy (PRM) aquifer solids rather than an inhibitory effect. This was also noted for the adsorption of p-DCB on the Cohansey aquifer solids in the presence of 2,4-DCP. The other systems (2,4-DCP on the Cohansey aquifer solids in the presence of p-DCB and p-DCB on the PRM aquifer solids in the presence of 2,4-DCP) exhibited indiscernable competitive effects. The aquifer solids with the larger organic content adsorbed more of each substance. The data obtained using the more homogeneous aquifer solids evidenced less scatter.
Performance Assessment of Incinerators and High-Temperature Industrial Processes for Disposing of Hazardous Waste in the United States
Authors: Oppelt ET
Published: December 2008

Since 1982, the U.S. Environmental Protection Agency (EPA) has been conducting performance assessments of hazardous waste thermal destruction facilities in the United States. The principal objective of these tests has been to characterize emissions and determine if these facilities are capable of meeting the waste destruction and control requirements of the current EPA regulations and standards. To date, the test program has involved performance assessments at 9 incinerators and over 20 high-temperature industrial processes employing hazardous waste as a fuel supplement in their operations.

The testing has typically involved stack emissions assessment for SOx, NOx, particulate, hydrochloric acid (HCl), carbon monoxide (CO), carbon dioxide (CO2), oxygen (O2), metals, total hydrocarbon, and quantification of specific organic compound emissions. Engineering and other process operating variables (for example, excess air, steam load, and waste to fuel ratio) have also been recorded during the test program in order to examine the potential operating bounds for these facilities.

The purpose of this paper is to summarize the extensive results of this testing program, which has, in general, indicated that high organic compound destruction and removal efficiencies (99.99%) are achievable in these facilities. Effective (99%) control of HCl emissions was attained in facilities handling chlorinated organic wastes. The current EPA particulate standard of 180-mg/dry m3 was the most difficult standard to attain for incinerators.
Migration of Leachate Solution Through Clay Liner and Substrate
Authors: Yong RN , Warith MA , Boonsinsuk P
Published: December 2008

The migration of various contaminants in a sensitive soil, used as liner and in-situ substrate in an actual landfill site, is investigated in controlled laboratory column leaching tests. Using the actual leachate collected from the site, the laboratory tests show good attenuation of the heavy metals studied and lesser attenuation of the salts. Comparison between predicted and concentration profiles, using C1 as an example, shows that there is significant need to account for the time and spatial variation of the specific dispersion coefficients — caused by continued leaching or intrusion of the contaminants — if proper accord between predicted and measured profiles is to be achieved.
Remote Sensing Methods for Waste Site Subsurface Investigations and Monitoring
Authors: Wruble DT , van Ee JJ , McMillion LG
Published: December 2008

Detection and monitoring of subsurface contamination at waste disposal or storage sites can be expensive and uncertain with traditional sampling and measurement techniques. Remote sensing methods can greatly aid characterization of the subsurface and detection of contaminants in the vicinity of waste deposits. Inexpensive aerial remote sensing, such as photography or infrared scanning, can indicate subsurface contaminant movement and structure. Resistivity surveys and other surface remote sensor applications develop further details on subsurface geology and plumes. Most importantly, development of detailed vertical profiles with subsurface sensors provides indispensable data for ultimate characterization of the subsurface environment. Subsurface geophysical remote sensing techniques commonly used for deep subsurface characterization associated with petroleum or mineral exploration must be modified to be used effectively in the shallow depth range associated with surface disposal or storage sites.
Procedures for Characterizing Effects of Organics on Solidification/Stabilization of Hazardous Wastes
Authors: Tittlebaum ME , Eaton HC , Cartledge FK , Walsh MB , Roy A
Published: December 2008

The mechanisms whereby organic hazardous wastes interact with cement matrices is important for characterizing existing and future solidification/stabilization technologies and for evaluating these technologies using short-term testing techniques. In the complex chemistry of cement setting reactions, many phases are formed. Consequently it is necessary to use a variety of microscopic and microanalytical tools in studies of these systems. Methods employed in the present study are scanning electron microscopy, energy dispersive X-ray analysis, electron probe microanalysis, and X-ray powder diffraction. Examples of the application of these techniques to studies of cement containing para-bromophenol are presented. The organic appears to occupy several different environments, and an inhomogeneous distribution of the phenol among the phases of hydrated portland cement can be demonstrated.
Developing Guides for Sampling and Analysis of Ground Water
Authors: Bone LI
Published: December 2008

ASTM Committee D-34 on Waste Disposal has two subcommittees that are concerned with ground-water sampling: D34-02-08 on Groundwater Analysis and D34-01-01 on Environmental Monitoring and Sampling. Subcommittee D34-02-08 has been reviewing the Environmental Protection Agency's (EPA) Proposed SW 846 Method 8600 for screening ground water for Appendix VIII compounds. Subcommittee D34-01-01 has prepared Guides for Sampling Ground Water Monitoring Wells and Pore Water Sampling in the Vadose Zone. The ground-water guide discusses flushing requirements, well sampling devices, and sample container and preservation requirements. The author presents some of the guide's discussion concerning the advantages and disadvantages of sampling procedures and devices and offers some recommendations based on his own experience. Flushing 5 to 10 well volumes or until some parameter, such as pH or conductivity is stabilized, is recommended. Bailers, bladder pumps, or gas driven piston pumps are recommended, and the importance of preplanning sampling operations is emphasized.
The Results of an Interlaboratory Study of a Column Method for Leaching Solid Wastes
Authors: Miner RA , Van Maltby C , Dell LR
Published: December 2008

A method for generating aqueous leachates from solid wastes in a column apparatus has been drafted by ASTM Subcommittee D34.02.02 on Column Extraction Methods. The method was subjected to a five-laboratory study using fly ash as a waste material. The within laboratory relative standard deviation for metals (based on the results from three laboratories with multiple columns) was found to be approximately 35%. The overall single test reproducibility in terms of relative standard deviation (based on the results from these same laboratories) was approximately 55%. This excludes interlaboratory analytical effects because all analyses were performed by a central laboratory.
Batch Type 24-h Distribution Ratio for Contaminant Adsorption by Soil Materials
Authors: Griffin RA , Sack WA , Roy WR , Ainsworth CC , Krapac IG
Published: December 2008

An investigation was undertaken to develop a standardized batch adsorption procedure that uses the initial and 24-h solution concentrations to calculate a distribution ratio Rd between solutes and soil materials. In developing these procedures, it was found that the method of mixing the solute-soil mixtures influenced the amounts of solute adsorbed. To ensure reproducibility, a National Bureau of Standards rotating tumbler was adopted as the mixing system. An interval of 24 h was established as a valid operational definition of reaction time for determining Rd values.

Interlaboratory testing was conducted with arsenic and cadmium using soil materials having a range in physiochemical properties. The interlaboratory coefficients of variation (CV) were generally less than 10%. The precision of an Rd measurement for a species that meets the criteria of being stable and nonvolatile should yield percent CV within the range established. The method has not been tested for organic solutes and is not considered viable for volatile chemical species. The method is considered a reliable and useful technique for comparing the adsorption properties of various soil materials under a given set of conditions.
Laboratory and Waste Management for Safety and Regulatory Compliance
Authors: McKee TM , Allison RC
Published: December 2008

Federal, state, and local rules and regulations often affect even small generators of waste materials. Chemical laboratories are perfect examples with a need to develop procedures to dispose of small quantities of laboratory wastes in a safe and environmentally acceptable manner.

Recognizing a need, the ASTM D-34 committee on waste disposal created its Subcommittee D34.01.05 on Sample Disposal with the direct responsibility for developing guidelines for laboratories. While it was impossible to address the disposal of all wastes from all types of laboratories, the guidelines did address the more common laboratory waste streams. They are applicable, but not limited to, analytical chemistry, process control, and research or life science laboratories.

The recommended guidelines for disposal cover the following topics: (1) the classification of waste for shipping and manifesting by common or generic name and by Department of Transportation requirements; (2) the segregation of wastes for recovery, pretreatment, or disposal; (3) the procedures for recovery of materials, or to render them nonhazardous and amendable for landfilling or in-house disposal, or to prepare them for disposal in authorized chemical disposal sites; and (4) the designation of a specific revoery or pretreatment and disposal method for each type of waste.
Retrofit of a High Power Nd:Glass Laser System with Liquid Crystal Polarizers
Authors: Jacobs SD , Cerqua KA , Kessler TJ , Seka W , Bahr R
Published: December 2008

The glass development laser (GDL), has been operating at the Laboratory for Laser Energetics since 1978. This Nd:phosphate glass system produces high peak power optical radiation at λ = 1054 nm or λ = 351 nm for use in studying the interaction physics of intense laser beams with matter. The amplifier staging incorporates the propagation of linearly and circularly polarized light in rod amplifiers which vary in diameter from 16 mm to 90 mm. Numerous quartz or mica quarter waveplates and Brewster angle dielectric thin film polarizers are required to limit accumulated phase retardation between amplification stages, and to accommodate interstage Pockels' cell isolation switches.

We have recently replaced most of the waveplate-dielectric polarizer combinations in GDL with liquid crystal polarizers. Comprised of 11 μm thick cholesteric fluids sand-wiched between optical quality glass plates, liquid crystal polarizers provide excellent polarization properties, low insertion loss, angular insensitivity, and laser damage resistance at λ = 1054 nm.

The design, fabrication and performance of left-handed and right-handed circular polarizers will be discussed.
Picosecond Damage in Y2O3 Stabilized Cubic Zirconia
Authors: Mansour N , Soileau MJ , Van Stryland EW
Published: December 2008

The hardness, strength, and transparency of cubic zirconia ZrO2 makes it a good candidate as a laser window material; however, to obtain these qualities a relatively large percentage of Y2O3 is added to stabilize the crystals and increase their mechanical strength. As impurities are often regarded as the initiators of laser-induced damage we have performed a study of the damage thresholds of optical quality ZrO2 stabilized with Y2O3. These thresholds have been measured with picosecond 1.06 μm laser pulses in crystals having Y2O3 concentrations of 9.4%, 12%, 15%, 18%, and 21%. We found that the addition of Y2O3 for increasing the mechanical strength of zirconia does not necessarily lead to a decrease in the damaging irradiance. In addition, the thresholds for ZrO2 are comparable to those of NaCl.
Pulsed Laser Induced Optical Damage Threshold In Nd:Cr:GSGG Crystal
Authors: Acharekar MA , McCarthy DP , Blachman R
Published: December 2008

Gadolinium scandium gallium garnet (GSGG) doubled doped with neodymium (Nd) and chromium (Cr) shows higher efficiency than the commonly used neodymium doped yttrium aluminum garnet (Nd:YAG) laser. The performance characteristics of 6.3 mm diameter by 100 mm long and 5 mm diameter by 65 mm long Nd:Cr:GSGG rods were obtained. A flashlamp pumped Nd:Cr:GSGG laser was operated in both normal and Q-switch modes. The performance data for the material will be presented and compared with Nd:YAG laser rod.

Q-switch output pulses of Nd:Cr:GSGG laser with 17 ns pulse width and 1.061 μm wavelength were used to study surface and bulk damage in coated and uncoated, polished samples of Nd:Cr:GSGG crystal. These optical damage threshold measurements were compared by measuring damage threshold of fused silica and BK-7 glass samples using the same experimental set up. Nd:Cr:GSGG damage threshold was higher than BK-7 glass and slightly lower than fused silica.
Leed Analysis of Pulsed Laser Damage to Mo(100) Surfaces
Authors: Helms AL , Cho C-C , Bernasek SL
Published: December 2008

Low Energy Electron Diffraction (LEED) and Auger Electron Spectroscopy (AES) have been used to investigate the effect of Q-switched, frequency doubled Nd:YAG laser pulses on the surface structure and composition of Mo(100). The experiments were conducted in a special ultra-high vacuum (UHV) chamber which allowed the characterized surfaces to be irradiated in an UHV environment. Good epitaxial regrowth of the Mo(100) surface was observed after laser surface melting as evidenced by LEED. Changes in the spot profiles and their dependence on incident electron energy after irradiation suggest the incorporation of defects and the formation of random islands on the surface. The study included laser fluences both above and below the melt threshold of the surface. Additionally, the annealing action of laser pulses on surfaces that had been heavily damaged by Ar+ ion bombardment was investigated.
Studies of CO2 Laser Induced Damage to Infrared Optical Materials and Coatings
Authors: Gibson DR , Wilson AD
Published: December 2008

A new versatile CO2 laser damage facility which uses a TEA laser giving a single mode output of up to 15 Joules per pulse is described. The temporal characteristics of the pulse can be readily varied. A method of producing pulses with durations less than that of the gain switched spike using plasma-based temporal attenuators is described. Data is presented on a range of infrared optical materials as well as commercial and experimental AR coatings and dielectric reflectors. Detailed examination of the damage morphologies coupled with the dependence of the damage threshold on pulse length is used to determine the mechanisms of laser induced damage.
Surface Potential as a Laser Damage Diagnostic
Authors: Becker MF , Kardach JA , Stewart AF , Guenther AH
Published: December 2008

We investigated the relationship between surface potential changes and N-on-1 laser surface damage on a wide range of materials. The surface potential or work function difference was measured as a function of position by a small non-contacting Kelvin type probe. This design and operation of the probe is described. Using this probe, the change in surface potential due to laser irradiation was mapped with a ∼1 mm resolution. Although no consistent pre-damage changes in potential were observed, all larger damage features had surface potential changes associated with them. The insulating materials studied, fluoride and oxide thin films, bare fused silica and magnesium fluoride substrates, all showed the accumulation of negative charge in areas more than ten times larger in diameter than the laser beam spot or damage area. This initial charge was observed to decay on the time scale of hours to a lower fixed value of potential associated with permanent damage to the surface.
Oxygen Threshold for Ion-Bean Sputter Deposited Oxide Coatings
Authors: Demiryont H , Sites JR
Published: December 2008

Reactive ion-beam sputter deposition, using a mixed argon-oxygen beam, has been demonstrated to be an effective technique for fabrication of dense, amorphous TiO2, Ta2O5, and SiO2 coatings. For both elemental and oxide targets there is a critical level of oxygen in the beam necessary to produce stoichiometric films. This threshold is seen in the films' composition, refractive index, and optical band gap. With elemental targets there is a major reduction in deposition rate at the oxygen threshold, strongly implying that an oxide layer is formed on the target, and is subsequently sputtered onto the substrate.
Tomorrows Coatings Today — They Need Help
Authors: Stewart AF , Guenther AH
Published: December 2008

A representative set of dielectric coatings prepared using novel deposition techniques have been evaluated. Single layer coatings of ZrO2 and Al2O3 were deposited on super polished fused silica substrates by conventional electron beam, electron beam in UHV, electron beam with ion beam assist, CW laser in UHV, and an advanced epitaxial technique. Characterization included total integrated scatter, spectrophotometry, x-ray diffractometry and pulsed laser damage testing at 532 nm. Our results indicate that considerable additional work will be required to optimize the optical performance of coatings produced by these novel deposition methods, let alone understand the relationship between deposition process, structure, optical characteristics and durability.
Thermal Properties of Optical Thin Film Materials
Authors: Decker DL , Koshigoe LG , Ashley EJ
Published: December 2008

The performance of coatings for high power laser application depends not only on the optical properties of the films, but the thermal properties as well. An examination of the literature indicates that virtually all work has concerned the optical absorptance or reflectance, and that virtually no thermal property data are available for optical materials as thin films. Since it is known that the optical absorptance is often larger by orders of magnitude for a material as a thin film compared to bulk, a similar change (decrease) in thermal diffusivity might be expected. Of additional concern are the interfacial thermal barriers occurring at the boundaries between films. This paper presents experimental data for thin-film materials including Al2O3 and SiO2 deposited in high vacuum. A simple theoretical analysis is also presented at well as recommendation for further work.
An Initial Study of: The Inclusion Model for Repetitively Pulsed Laser Damage
Authors: Lange MR , McIver JK , Guenther AH
Published: December 2008

The inclusion model of laser initiated damage is extended to include an arbitrary but repetitive and reproducible variation of the laser irradiation in time. The controlling influence of the thermal properties of the film/substrate system and inclusion, together with the duty cycle of the laser, i.e., the duration and energy of a single pulse and of the repetition rate, on the damage threshold is discussed. The predictions of this model are then compared to the results of the single-shot model of inclusion dominated damage. Suggestions for experimental tests of this model are given.
Fatigue Strength of Bolted and Adhesive Bonded Structural Steel Joints
Authors: Albrecht P , Sahli AH
Published: December 2008

This study examines the feasibility of adhesive bonding and bolting tension splices, beam splices, and cover plates. The results show that bonding the contact surfaces significantly increased the fatigue life of high-strength bolted splices. Bonding cover plates to the tension flange of the beam increased the fatigue life by a factor of 20 as compared to that of conventionally welded cover plates. Replacing welds with adhesives and bolts virtually fatigue-proofs structural steel details subjected to highway bridge loading.