bluuebunny/crossref_metadata_2025 huggingface dataset:
Bolt Clampup Relaxation in a Graphite/Epoxy Laminate
Authors: Shivakumar KN , Crews JH
Published: March 2009

A simple bolted joint was analyzed to calculate bolt clampup relaxation for a graphite/epoxy (T300/5208) laminate. This study was based on a viscoelastic finite-element analysis of a double-lap joint with a steel bolt. Clampup forces were calculated for various steady-state temperature-moisture conditions using various exposure durations.

The finite-element analysis predicted that clampup forces would relax even for the room-temperature dry (RTD) condition. The relaxations were 8, 13, 20, and 31% for exposure durations of 1 day, 1 month, 1 year, and 20 years, respectively. As expected, elevated temperature and moisture levels each increased the relaxation rate. The viscoelastic effects of elevated temperature and moisture appeared to be additive.

Based on the finite-element results, a simple empirical equation was developed for clampup force relaxation. First, the equation was postulated to have the same functional form as the inverse of the material compliance in the thickness direction. Second, the two constants in the equation were fitted, by a least-square regression analysis, to the RTD results, Finally, the equation was generalized to include temperature- and moisture-dependent viscoelastic effects by using material hygrothermal shift factors. This generalized equation was used to calculate clampup forces for the same temperature-moisture conditions as used in the finite-element analysis. The two sets of calculated results agreed well.

The clampup equation was further evaluated by comparing calculated and measured clampup forces. Instrumented (strain-gaged) bolts were monitored throughout a 100-day test period. Three steady-state test environments were used: RTD, room temperature with a laboratory ambient moisture level (0.46%), and an elevated-temperature (66°C) dry case. The equation agreed reasonably well with the test data.
A Conceptual Model of the Thermal-Spike Mechanism in Graphite/Epoxy Laminates
Authors: Adamson MJ
Published: March 2009

The influence of a thermal spike on a moisture-saturated graphite/epoxy composite was studied in detail. A single thermal spike from 25 to 132°C was found to produce damage, as evidenced by a significant increase in the level of moisture saturation in the composite. Approximately half of this increase remained after a vacuum-anneal at 150°C for seven days, suggesting the presence of an irreversible damage component. Subsequent thermal spikes created less and less additional moisture absorption, with the cumulative effect being a maximum or limiting moisture capacity of the composite. These observations are explained in terms of a model previously developed to explain the reverse thermal effect of moisture absorption in epoxy and epoxy-matrix composites. This model, based on the inverse temperature dependence of free volume, improves our understanding of thermal-spike effects in graphite/epoxy composites.
A Residual Strength Degradation Model for Competing Failure Modes
Authors: Whitney JM
Published: March 2009

A residual strength degradation model is presented which deals with both tensile and compressive strength degradation as competing failure modes. Static strength distributions are assumed to follow a two-parameter lognormal distribution, whereas the residual strength degradation equations are based on a three-parameter power law model. A procedure is outlined for determining the parameters in the model. Comparisons are made between theory and experiment for constant amplitude tension-tension and tension-compression fatigue data. Both residual tensile and residual compressive data obtained under these two load histories are considered.
Data Comparability: An Objective for Precipitation Chemistry Monitoring
Authors: Jansen JJ
Published: March 2009

Data comparability is a stated or implied goal of a number of networks today (for example, the Utility Acid Precipitation Study Program [UAPSP]). This concept is indeed very important if a research objective such as the “national objective” on precipitation chemistry monitoring is to be met using the combination of all the existing precipitation chemistry monitoring networks in North America. An analysis of the definition of data comparability shows that two steps are involved in establishing data comparability of two data sets: (1) to judge the adequacy of the data sets toward accomplishing the objective and (2) to determine the uncertainty of each data set and that of the combined data set.

Two methods are described to improve data comparability. The two methods can be represented by (1) the responsibilities of the data gatherer and (2) the responsibilities of the data analyst. In applying these methods towards meeting an example objective, it is shown that implementing and reporting quality control/quality assurance on the part of the data gatherers (that is, network operators) is the key stumbling block in the data analyst's attempts to determine the degree of data comparability. The UAPSP network is described, and the efforts to improve data comparability are discussed. The UAPSP has implemented both internal quality control and independent quality assurance to meet its responsibilities as a data gatherer. The UAPSP also sponsored a workshop in Aug. 1982 to promote discussion of ways to improve data comparability among the networks in the future.
Spray-Applied Fire Resistive Coatings for Steel Building Columns
Authors: Bardell K
Published: March 2009

This paper describes the insulative value of spray-applied, cementitious and mineral-fiber fire resistive coatings for steel building columns. It presents results of high-temperature thermal property tests of the materials used as input to a two-dimensional heat flow analysis designed for predicting the fire resistance of hollow steel columns. The prediction is compared with actual fire test data. The influence of the thermal properties of the materials and their application thickness on fire resistance is discussed.
Corncob Granules and Pelleted Carriers—New, Controlled, Safer Methods of Handling Pesticides
Authors: Vander Hooven DIB
Published: March 2009

Uniformly graded corncob granules and finely ground corncob particles agglomerated into pelleted delivery systems are discussed.

These unique products, available in attractive commercial quantities, are described in terms of their chemical and physical constituents as well as the role they play today in agricultural chemicals. Stability data are also discussed.

Methods of applying active ingredients without the use of solvents are shown.

Altered (expanded) cob granules are shown in which the soybean oil carrying capacities have been increased from the traditional 15% to the now possible 25 to 30% loadings.

Pelleted pesticide carriers using finely ground corncob powders are shown to be safe, accurate methods of delivering active ingredients to targeted pest species.
Development of Water-Dispersible Granule Systems
Authors: Fleming JP , Hazen JL
Published: March 2009

This paper contains an example of a typical water-dispersible granule and a description of each of the ingredients found in the formulation. The study shows that even with products in the same chemical class, slight differences can produce significant differences in the performance characteristics.

In this experiment, dispersants were investigated. Although other variables were not studied, the authors believe that differences could also be observed by changing the other ingredients—that is, the wetting agents, agglomerating agents, diluents, and so forth.
Probabilistic Evaluation of Conservatisms Used in Section III, Appendix G, of the ASME Code
Authors: Jouris GM
Published: March 2009

In this paper the results of a probabilistic analysis for a pressure vessel are described in which the effects of various conservatisms used in Section III, Appendix G, of the ASME Boiler and Pressure Vessel Code are assessed. The methodology used is based on the introduction of probabilistic concepts into the deterministic calculations of Section III, Appendix G, so that the appropriate variability is reflected. By comparing the estimated probabilities of failure based on the various conservatisims, the approximate margin of safety in the design of a pressure vessel has been evaluated. From this analysis, it is concluded that this safety margin is considerable. Depending upon the conditions considered to be realistic in practice, the margin could be upwards of 10 or more orders of magnitude.
Applications of a Probabilistic Fracture Mechanics Model to the Influence of In-Service Inspection on Structural Reliability
Authors: Harris DO , Lim EY
Published: March 2009

A probabilistic fracture mechanics model of structural reliability is described that considers failure to occur as the result of subcritical and catastrophic growth of pre-existing cracks that escape detection. The model considers cracks to be two-dimensional and is capable of treating many of the input parameters as random variables and can consider arbitrary inspection schedules. The two-dimensional model is greatly simplified when one-dimensional cracks are considered, and an analytical treatment of the influence of in-service inspection for the one-dimensional case reveals that the ratio of failure rates with and without inspection is independent of the crack size distribution. Numerical results for two-dimensional cracks in a weld joint in a large reactor pipe show that the ratio of failure rates is not highly dependent on the initial crack distribution, even for this more general case. Thus, it appears that an assessment of the relative benefit of in-service inspection does not require accurate knowledge of the initial crack distribution. Additionally, the results show that leaks in large pipes are not very probable, but are much more likely to occur than a sudden double-ended pipe break.
Exploratory Study of Crack-Growth-Based Inspection Rationale
Authors: Walker EK
Published: March 2009

A relatively simple probabilistic model is developed having as its basic elements a log-normal representation of crack initiation and crack growth rates, the probability of crack detection, a crack growth curve, and a safety criterion based on a probability of residual strength equal to or less than limit load capability. Interrelationships between these model elements are explored through selected quantified examples. Some resulting internal relationships and trends are discussed.
S-N Fatigue Reliability Analysis of Highway Bridges
Authors: Albrecht P
Published: March 2009

This paper presents a method of calculating the expected fatigue failure probability of a structural detail, given the distribution of resistance and load. The resistance data, in terms of cycles to failure, come from previous laboratory tests. The load data come either from stress range histograms recorded on bridges or from loadmeter surveys. The proposed method replaces each histogram by an equivalent stress range and converts the latter into a distribution in terms of number of cycles. The problem is thus cast into the standard format for reliability analysis and allows one to calculate failure probabilities. Application of the method to designs in accordance with the AASHTO Specifications showed that fatigue failure probabilities for redundant load path (RLP) structures are inconsistent and vary greatly from PF = 9.2 × 10−2 for Category B to PF = 9.2 × 10−10 for Category E'. For nonredundant load path (NRLP) structures, they vary from PF = 5.1 × 10−2 for Category A to PF = 2.1 × 10−22 for Category E. It is proposed that the specifications be revised to include: (1) allowable stress ranges for RLP and NRLP structures with uniform failure probabilities; (2) explicit formulation of the specifications in terms of the actual number of single “fatigue trucks,” each causing an equivalent stress range; and (3) continuous definition of allowable stress range versus truck traffic volume. An example illustrates the design of a bridge, not covered by the AASHTO specifications, to a specified failure probability.
Influence of Microstructure and Environment on the Fatigue Crack Growth Fracture Topography of Ti-6Al-2Sn-4Zr-2Mo-0.1Si
Authors: Ruppen JA , McEvily AJ
Published: March 2009

An examination of fatigue fracture surfaces as influenced by microstructure (β processed versus α + β processed) and environment (air versus vacuum at 298 and 811 K) for a high-temperature creep-resistant near-α titanium alloy, Ti-6Al-2Sn-4Zr-2Mo-0.1Si, has been undertaken utilizing scanning electron microscopy. Results show that fracture topography is very sensitive to microstructural and environmental causes. Beta processing leads to a more irregular fracture surface than α + β processing. At low growth rates (10−6 mm/cycle) in air, shear mode growth predominates, resulting in large transgranular facets, whereas at growth rates of 10−5 in./cycle, striated and dimpled fracture features were present. At elevated temperatures, where oxidation effects were quite pronounced, particularly at low growth rates, the fracture surface was smoother than at room temperature, but faceting persisted to higher growth rates. In vacuum, however, the degree of faceting and striation formation was markedly reduced. Finally, the observed fractographic features influenced by microstructure and environment are discussed in terms of the mechanism of crack growth.
Fractographic Comparison of Plane-Strain Fracture Toughness, Instrumented Precracked Charpy, and Slow-Bend Precracked Charpy Tests on a Quenched and Tempered AISI 4340 Steel
Authors: Datta KP , Wood WE
Published: March 2009

Toughness testing of a quenched and tempered AISI 4340 steel has been carried out by precracked Charpy (instrumented and slow-bend) and fracture toughness test techniques. Results show that the toughness values, as a function of heat treatment, follow similar trends for identical heat-treatment schedules in each type of testing. Fractographic observations also indicate the same fracture initiation mode in all the tests for identical heat treatments, including an intergranular fracture mode associated with the temper embrittlement of the steel in question. It indicates that, in this particular application, mechanical testing variables such as specimen dimensions, crack length, crack length to width ratio, and strain rate have no effect on the fracture initiation process.
Correlation Between Fatigue Crack Growth Rate and Fatigue Striation Spacing in AISI 9310 (AMS 6265) Steel
Authors: Au JJ , Ke JS
Published: March 2009

Fatigue crack growth data were obtained for an AISI 9310 (AMS 6265) steel under various conditions. The effects of stress ratio, frequency, environment, and carbon content (strength) on both the fatigue fracture topography and the fatigue crack growth rate were studied. A good correlation was obtained between the fatigue striation spacing and the macroscopic crack growth rate for crack growth rates ranging from 10−4 to 10−3 mm/cycle.
Automatic Decreasing Stress-Intensity Fatigue Crack Growth Rate Testing Using Low-Cost Circuitry
Authors: Brown RC , Dowling NE
Published: March 2009

To run decreasing-K tests to very low growth rates, around 10−7 mm/cycle, it has previously been necessary to use a digital computer controlled system, or to manually shed the load at prescribed crack lengths. In this work, low-cost, off-the-shelf electronic circuitry was used to control decreasing-K tests so that very low crack growth rates were achieved. This was done automatically, using the compliance method of crack measurement for the electronic control inputs. By switching to constant load limit control, an increasing-K test may be conducted using the same specimen. This predetermined, decreasing-K technique was verified by comparing decreasing and increasing-K data at low growth rates for an alloy steel.
Analysis of Fatigue Crack Growth Rate Data from Different Laboratories
Authors: Fong JT , Dowling NE
Published: March 2009

A simple-minded yet quantitative approach to assessing interlaboratory fatigue crack growth rate data is proposed. Seven sets of da/dN versus ΔK data from six laboratories on nominally the same material and loading conditions in a cooperative test program sponsored by the Society of Automotive Engineers (SAE) are analyzed to illustrate this ad hoc approach. Each set of data is subjected to a standard first-order linear regression analysis based on the method of least squares. Three characteristics of the regression line [namely, the location of the “center” of the data, the slope, and the vertical half-width of the confidence band (for some specified level of confidence)] are used to define a composite measure of the closeness of one regression line to another. To illustrate the benefit of a statistically sound interlaboratory test program, the single-specimen SAE data are supplemented with fictitious replica data for the application of an interlaboratory data analysis procedure first proposed by Mandel (ASTM Standardization News, Vol. 5, No. 3, 1977, p. 17). “New” information based on the ad hoc approach of this paper and Mandel's method of interlaboratory data analysis is discussed in the context of other work on fatigue crack growth rate data analysis and the economic aspect of engineering testing.
Static and Fatigue Strength of High Load Intensity Steel-Hybrid Composite Bonded Scarf Joints
Authors: Greszczuk LB , Macander AB
Published: March 2009

This paper reports on analytical and experimental studies of the static and fatigue strength of high load intensity steel-hybrid composite bonded scarf joints. The hybrid composite consisted of T300/5208 at 0 deg and GY70/5208 at ±45 deg, with 0-deg direction being along the length direction of the joint. In sizing up scarf joints capable of carrying loads of 70 100 N/cm ≈ 40 000 lb per inch of width, properties of adherends, stiffness imbalance, coefficient of thermal expansion mismatch, and adhesive plasticity were taken into account. The joint test specimens were fabricated by cocuring at 450 K (350°F) the composite prepreg and the EA 951 Hysol adhesive. The scarf joints were tested in static tension, static compression, and tension fatigue. Test results showed the compressive strength of the scarf joint to be proportional to the scarf tip thickness, with joint strength increasing as the scarf tip thickness decreases. The fatigue strength was evaluated at 50, 60, and 70 percent of static ultimate strength using R = 0.05 and cyclic rate of 180 cpm. Also, the sensitivity of joint strength to bondline flaws was evaluated experimentally. For this purpose, a number of specimens containing debonds of various lengths and at various positions along the scarf length were fabricated and tested under static tension. The results from these tests were evaluated using fracture mechanics analysis. Limited data are presented on the repair of scarf joints that were tested to failure (and failed by microcracking and delamination) under tension fatigue. Preliminary experimental results are also presented on the response of a full-size [71.1-cm (28-in.)-wide] scarf joint in the skin of a box beam structural component simulating a foil structure.
Improving Composite Bolted Joint Efficiency by Laminate Tailoring
Authors: Eisenmann JR , Leonhardt JL
Published: March 2009

The objective of tailoring the laminate in a composite bolted joint is to uncouple the local bearing capacity from the influence of the laminate axial strain level. This can be accomplished by partitioning the laminate into two distinct regions, each serving a specific purpose. The primary region of the laminate typically contains a fairly high percentage of 0-deg plies and thus carries a high percentage of the overall axial load. The bearing region, in contrast, contains no 0-deg plies and thus carries only a small portion of the overall axial load. As a result, the bearing region is insensitive to the amount of axial load in the joint and can continue to serve the function of introducing the bolt loads into the laminate even at high levels of axial strain. This concept has been validated by static tests of single-fastener coupons, multiple-fastener joints, and full-scale components. Even at the complexity level of the full-scale component, the tailored laminate approach provided a 24 percent increase in weight efficiency and a 62 percent increase in axial strain level compared to a companion component utilizing nontailored laminates.
Demonstration of the Ecological Effects of Streptomycin and Malathion on Synthetic Aquatic Microcosms
Authors: Taub FB , Read PL , Kindig AC , Harrass MC , Hartmann HJ , Conquest LL , Hardy FJ , Munro PT
Published: March 2009

Small synthetic microcosms have been developed in the authors' laboratory to provide replicate aquatic communities with interspecies competition within primary, secondary, and recycling trophic levels. The microcosms display nutrient depletion, algal competition and succession, and algal depletion through grazing and nutrient depletion. Streptomycin acted as a selective algal toxicant, reducing all indexes of primary production temporarily, and then modifying the algal dominance relationships over the 63-day experiment, although no active streptomycin could be detected by Day 28. Daphnia populations were reduced and ostracod populations markedly increased in the streptomycin-treated microcosms. These results were consistently shown in three successive microcosm experiments. In contrast, malathion caused a temporary reduction in the number of grazers and a concurrent algal bloom. Degradation of malathion was presumed from the recovery of the grazer populations, which was accompanied by the elimination of the algal bloom.

The synthetic microcosms, being composed of distilled water, silica sand, reagent-grade chemicals, and organisms that are easily reared in the laboratory, show promise of providing a nonsite specific, reproducible ecosystem-level bioassay.
A Microcosm Study of Lindane and Naphthalene for Model Validation
Authors: Staples CA , Dickson KL , Saleh FY , Rodgers JH
Published: March 2009

Lindane and naphthalene were used in a series of flow-through microcosms to validate predictions of two environmental fate models—the exposure analysis modeling system (EXAMS) and simplified lake and stream analysis (SLSA). The microcosms' physical transport characteristics were carefully measured and used as input parameters to the models, along with laboratory data on lindane and naphthalene rate constants and coefficients. The results show that both models accurately predict the chemicals' concentrations in the water compartment. Observed concentrations in the sediments were two to three orders of magnitude lower than the models' predictions, even though the overall mass balance accounted for about 90% of the chemicals' input. Lack of agreement between observed and predicted sediment concentrations may be attributed to (a) the variability of the sediment partition coefficient values, (b) the slow rate of sediment loading, (c) vertical stratification of the chemicals in the sediment, and (d) microbial degradation of the chemicals in the sediment.
The Relationship Between the Toxicity and Structure of Nitroaromatic Chemicals
Authors: Bailey HC , Spanggord RJ
Published: March 2009

The acute toxicities of nitrotoluene, dinitrotoluene, trinitrotoluene, aminonitrotoluene, aminodinitrotoluene, and dinitrobenzene isomers were evaluated in fathead minnows. For the nitroaromatics, toxicity appeared to be related to the number and orientation of nitro groups; compounds with nitro groups positioned ortho or para to each other were appreciably more toxic than isomers having the nitro groups in the meta orientation. In contrast, the toxicities of the aminonitrotoluenes and aminodinitrotoluenes were not related in any obvious way to their structures. Two mechanisms may account for the differences in toxicity between the nitroaromatic isomers: (1) nucleophilic displacement of a nitro group and (2) reduction of a nitro group. The available data indicate that reduction of a nitro group is the more likely pathway.
Population Approaches to Aquatic Toxicology
Authors: Vinegar MB
Published: March 2009

Field studies in which age-specific survivorship and fecundity are measured can provide data for the validation of laboratory studies conducted to assess the effects of toxic materials on aquatic species. Comparison of the variability of age-specific survivorship and fecundity in polluted versus nonpolluted areas would provide insight into the consequences of pollution at the population level. Techniques which permit prediction of population structure and growth from age-specific survivorship and fecundity schedules are described. These techniques include the life table and the Leslie matrix. Examples of population studies in which these techniques may be applied are given.
Toxicity of a Complex Munitions Wastewater to Aquatic Organisms
Authors: Liu DHW , Bailey HC , Pearson JG
Published: March 2009

The toxicity to freshwater organisms of a complex munitions effluent called condensate wastewater was determined using a novel and relatively economical approach proposed by Pearson and co-workers at the Second Annual ASTM Symposium on Aquatic Toxicology. Applicable only to complex wastewaters in which the concentrations of the individual chemical components are relatively constant over time, the approach emphasizes performing toxicity and related tests on a chemical mixture representative of the actual wastewater, with secondary attention being directed toward testing the individual chemical components, which is the conventional approach. The testing program comprised several series of static acute toxicity tests on authentic wastewater, artificial wastewater, and selected components to identify the conditions under which they are most toxic and to identify the most sensitive species; a series of flow-through acute toxicity tests on the artificial wastewater using the most sensitive species; a series of short-term bioconcentration tests; several early life-stage tests; and, finally, several life-cycle chronic tests. Twelve species representing three trophic levels were employed in the program.

It was concluded that the approach economically and rapidly provided a sufficient data base for assessing the effects of the wastewater on aquatic life. Two modifications were recommended to decrease the cost and time of obtaining the data. One was to perform a static and a flow-through test early in the testing program to identify the most appropriate exposure condition to use in the initial portion of the program. The other was to compute the octanol-water partition coefficients of the organic components of the wastewater before performing any bioconcentration test and to use the coefficients to determine if bioconcentration tests are necessary.
Uptake and Toxicity of Organic Compounds: Studies with an Aquatic Macrophyte (Lemna minor)
Authors: Lockhart WL , Billeck BN , de March BGE , Muir DCG
Published: March 2009

Aquatic macrophytes have been the subjects of relatively little research attention, either for their ability to accumulate pollutants or for their susceptibility to any toxic action of pollutants. Duckweed (Lemna minor) clones were maintained in axenic culture and were exposed to several carbon-14 (14C) labeled compounds added to the culture medium. Transfer of radioactivity from media to plants (bioconcentration) was described empirically with regression equations incorporating exposure times and concentrations, partition coefficients, and types of water used to make the culture media. In separate experiments, the growth of cultures in terms of frond numbers was described as a function of exposure time for several concentrations of the herbicides terbutryn, ethalfluralin, and fluridone. Bioconcentration and growth equations were then used to estimate those herbicide residues that should be associated with reductions in culture growth.
Contamination of Groundwater Samples with Poly(Vinyl Chloride) Adhesives and Poly(Vinyl Chloride) Primer from Monitor Wells
Authors: Sosebee JB , Geiszler PC , Winegardner DL , Fisher CR
Published: March 2009

The potential for contamination of groundwater samples by poly(vinyl chloride) (PVC) primer and adhesive was studied in both a laboratory simulation and actual groundwater samples. Tetrahydrofuran, methylethylketone, methylisobutylketone, and cyclohexanone were identified as the major constitutents of PVC primer and adhesive, and were found to be leached into the water surrounding bonded joints. The amount of organics released to the water declined with successive washes of water. The occurrence of such compounds can mask the presence of priority pollutants and create uncertainties in the determination of groundwater quality. Recommendations are given for the elimination or minimization of potential problems.
Leach Testing of Foundry Process Wastes
Authors: Boyle WC , Ham RK , Pastene J , Stanforth R
Published: March 2009

Emission control dusts, sludges, and mixed foundry process wastes were sampled from 21 foundries in Michigan and Pennsylvania and subjected to the pH 5 acetic acid extraction procedure (EP) specified by the U.S. Environmental Protection Agency (EPA) under the Resource Conservation and Recovery Act (RCRA) to define whether a waste is hazardous. This was in accordance with EPA's concern about cadmium, chromium, and lead extractions from such wastes. In addition, distilled water extractions were performed on all wastes, and controlled pH extractions ranging from pH 4 to 8 were performed on selected wastes. Finally, total metal contents were obtained to determine the percentages of the three metals extracted.

Emission control dusts and sludges from 9 of the 21 foundries were found to be EP toxic with respect to cadmium or lead or both. None were chromium toxic. Extraction was highly pH dependent, with much lower concentrations obtained at higher pH levels. Distilled water extractions resulted in one emission control waste being classified as EP toxic. Mixing emission control wastes with other process wastes resulted in a mixture much less likely to be classified EP toxic from that foundry.

The percentages of metals released in the EP test ranged from basically zero to 39% for cadmium, <1 to 12% for lead, and basically zero to 0.5% for chromium.
Testing Procedure for Evaluating Codisposal of Industrial Wastes and Municipal Refuse with Particular Reference to Pesticides
Authors: Stevens C , Jenkins DKW , Wilson DC
Published: March 2009

For a number of years, the Waste Research Unit of the Harwell Laboratory has been conducting research on the codisposal of industrial waste and municipal refuse as a practical and environmentally acceptable disposal option. Codisposal depends on utilizing the attenuation capacity of the refuse, and involves mechanisms such as dilution, biodegradation, adsorption, and precipitation.

To make a closer comparison with a codisposal site, laboratory-scale landfill experiments have been designed with the aim of studying the behavior of pesticide wastes. Four pesticides were selected for investigation, namely lindane, pirimiphos-methyl, (4-chloro-2-methylphenoxy) acetic acid (MCPA), and atrazine. Leachate monitoring revealed that the migration of MCPA, atrazine, and pirimiphos-methyl through municipal wastes was closely related to their solubility in water. The results for lindane are not yet available. The attenuative capacity of the refuse was investigated by comparing the concentration of pesticide in leachate immediately below the layer of pesticide waste and at the base of the column. Significant attenuation of MCPA and atrazine was observed.

The use of destructive sampling produced additional information in relation to attenuation, the effect on landfill microflora, and persistence of the pesticides under landfill conditions. The marked persistence of pirimiphos-methyl, a pesticide normally considered to be short-lived under agricultural conditions, illustrates that predictions based on extrapolation from agrarian practice are misleading. The results emphasize the importance of laboratory-scale experiments in the study of landfill science.
A Method for Evaluating the Soil's Effective Cation Exchange Capacity and Exchangeable Base Content Using Silver-Thiourea
Authors: Hoddinott KB
Published: March 2009

Measurement of the soil's in situ or effective cation exchange capacity (ECEC) is of major concern to professionals dealing with land disposal of cation-containing wastes. The ECEC is a measurement of the amount of excess negative charge a unit weight of soil will display under the environmental conditions experienced in the field. The measurement is accomplished by extracting all of the cations that would be released under field conditions using an unbuffered 0.01 M silver-thiourea solution and analyzing this extract for total calcium, magnesium, hydrogen, aluminum, potassium, and sodium. The ECEC then is calculated as the sum of these six cations in units of milliequivalents per 100 g of oven-dried soil.
Scientific Basis of Hazardous Waste Immobilization
Authors: Malone PG , Larson RJ
Published: March 2009

Estimates from the U.S. Environmental Protection Agency indicate the United States produced approximately 59 million tons of hazardous industrial wastes in 1981. Much of this material eventually will be disposed of in landfills. New waste forms produced for improved containment would greatly reduce the hazard associated with movement of the waste into the surrounding environment. Present technology in containment of wastes involves coating grains of waste material in inert material, imbedding waste in polymer matrixes, or coating monoliths with inert material. A number of simple chemical concepts can be used to produce improvements in containment of toxic materials. These include adsorption, chemsorption, passivation, diadochy, and reprecipitation. Each of these concepts is explained and containment of specific waste types are used as examples of each new containment system.
Development of a Solvent Extraction Method for Determining Semivolatile Organic Compounds in Solid Wastes
Authors: Warner JS , Landes MC , Slivon LE
Published: March 2009

This study was undertaken to develop an improved method for determining the total content of individual semivolatile organic compounds in solid wastes. The requirements of the method are as follows: applicable to a wide range of specimen matrixes; applicable to a wide range of compounds; quantification range of 1 ppm to 100%; acceptable recovery and reproducibility; and easily performed at reasonable cost.

The waste matrixes of interest include aqueous sludges, dry solids, soils, tars, oils, and oily sludges. The compounds of interest include aromatic halocarbons, aromatic hydrocarbons, aromatic nitro compounds, chlorinated pesticides, phosphates esters, halogenated ethers, phenols, anilines, quinolines, and other extractable organic compounds having boiling points in the range of 150 to 500°C.

The method developed is a dry neutral extraction procedure that involves a single extraction with methylene chloride under neutral conditions with anhydrous sodium sulfate added to remove any water present. Sonification with a high-intensity sonic probe is used to promote the interaction of the extraction solvent with the waste. Screening steps are incorporated into the method to determine the neutralization requirement of the specimen, the residue weight of the extract, and the optimum concentration of the extract for subsequent analysis. Gas chromatography-mass spectrometry (GC-MS) analysis using a fused silica capillary column is used to analyze the extract.

The dry neutral extraction method shows promise in meeting the requirements specified. The estimated quantification limit is 1 ppm for specimens that contain up to 1 mg/g of solvent extractable material and proportionately higher for other specimens. The mild extraction conditions used mimimize any losses from chemical reactivity. No emulsion or phase separation problems are encountered. The use of a single extraction under neutral conditions as employed in the method has been shown to be suitable for the extraction of a wide variety of compounds including phenols, anilines, and neutral compounds.
X-Ray Fluorescence Spectrometry for Analysis of Fly Ash Column Leachates
Authors: Young HW , Boybay M , Young JC , Demirel T
Published: March 2009

An investigation was conducted to determine the suitability of X-ray fluorescence (XRF) for analyzing the complex mixture of elements in fly ash leachates.

XRF analysis was found to provide reasonably accurate measurement with coefficients of variation ranging from 2 to 8% for most elements. Sources of error included interferences by stimulation of fluorescent emissions by strong secondary fluorescent radiation, overlap of emission peaks, and adsorption of fluorescent emission from one element by others.

Standardization required preparation of complex mixtures of elements similar in composition to that of leachates. This required considerable preparation time and effort, but once the standards were stored in instrument memory, analysis for as many as 30 elements in leachate specimens required only about 60 min. This study showed that XRF potentially is a valuable tool for analysis of the complex elemental mixtures in fly ash leachates, but additional work is needed to reduce error and increase instrument sensitivity.
Margins of Safety in the Assessment of Aquatic Hazards of Chemicals—Some Regulatory Viewpoints
Authors: Reisa JJ
Published: March 2009

This paper discusses the use of safety margins in aquatic hazard assessment from the point of view of a regulatory agency—specifically, the Office of Toxic Substances of the U.S. Environmental Protection Agency. Principles of application of the safety margin concept are discussed, including the complexity of balancing the myriad, often conflicting, factors involved in determining general risk assessment procedures and also evaluations tailored for specific purposes.
Selenium: A Hazard Assessment and a Water Quality Criterion Calculation
Authors: Adams WJ , Johnson HE
Published: March 2009

An aquatic environmental hazard assessment for inorganic selenium compounds was performed. Studies on environmental exposure concentrations, bioconcentration potential, and acute and chronic toxicity to aquatic organisms were reviewed. An average aqueous environmental exposure concentration of 1.0 μg/litre was calculated, using data from 22 lakes. The geometric means of the maximum acceptable toxicant concentrations (MATCs) for fathead minnows, rainbow trout, Daphnia magna, mysid shrimp, and sheepshead minnows were 0.22, 0.18, 0.13, 0.36, and 0.67 mg/litre, respectively. The safety factors, based on the ratio of the chronic geometric mean of the MATC to the average environmental exposure concentration, were determined to be greater than 130 for all aquatic species tested. The data suggest that existing aqueous environmental levels of selenium present little hazard to aquatic life.

The aquatic toxicity data base developed in the present study, together with previously reported information, was used to calculate a water quality criterion. The authors estimate that a concentration of 52 μg/litre, if not exceeded, should provide adequate protection for most aquatic species.
Great Lakes Monitoring Activities
Authors: Tebo EJ , Bowden RJ
Published: March 2009

A brief discussion is given of the multimedia, multijurisdictional, multipurpose monitoring program in the Great Lakes basin. Major conclusions of the intensive 2-year study on Lake Michigan are presented. The fish flesh monitoring program, which has been increasing in importance and intensity, is described in some detail.
Use of Bluegill Toxicity Indexes in Illinois
Authors: Lubinski KS , Sparks RE
Published: March 2009

Toxicity indexes that relate concentrations of up to 20 toxicants to their acute lethal effects on bluegill, Lepomis macrochirus (Rafinesque), have been compiled during three water research projects in Illinois. Indexes were compiled for individual stream stations by expressing each toxicant concentration as a fraction of its 96-h median lethal concentration (LC50) to bluegill (adjusted when possible for varying conditions of pH, temperature, dissolved oxygen, and hardness). The resulting component toxicities in bluegill toxic units (BGTUs) were added to yield a toxicity index for each station. Computer programs were developed to perform these calculations using data generated routinely by established water quality monitoring programs or by short-term spot surveys.

The objectives of the projects for which toxicity indexes were compiled included: (1) assessment of Illinois River water quality for fish life, (2) identification of the relationships between fish populations and ammonia and chlorine in sewage discharges, and (3) development of a continuous stress function to evaluate the responses of aquatic communities to environmental and pollutional factors. The projects have resulted in useful comparisons of stream toxicity values to fish numbers and diversity. Although the question of whether the acute effects of combinations of toxicants are additive may never be resolved, toxicity indexes have provided valuable comparisons of water quality at different stations, and at the same station through time, and have identified potentially dangerous toxicant problems.
Acute Toxicities of Equimolar and Equitoxic Surfactant Mixtures to Daphnia magna and Lepomis macrochirus
Authors: Lewis MA , Perry RL
Published: March 2009

The acute toxicities of anionic, nonionic, and cationic detergent surfactants to Daphnia and bluegill were determined for individual surfactants and for binary and ternary surfactant mixtures. Data were analyzed using several models, including toxic units, the additive index, and concentration and response addition.

The effects of the single surfactants, in decreasing order of toxicity, were as follows: in Daphnia, the effects were cationic, nonionic, and anionic; in bluegill, nonionic, anionic, and cationic. Approximately 72 percent of the binary and ternary mixtures were less than additive in response to either organism when analyzed by toxic units or by the additive index. Approximately 24 percent of the mixtures demonstrated simple addition using these methods. The anionic-cationic mixtures were synergistic to bluegill and in one case to Daphnia. The toxicities of the majority of mixtures fit response and concentration additive models; conformity to the response additive model was most common. Response addition, as applied and evaluated during the present investigation, offers an approach for early estimation and prediction of the toxicities of surfactant mixtures.
New Design and Use of a Fish Metabolism Chamber
Authors: Schmidt EJ , Kimerle RA
Published: March 2009

A 10-litre rectangular fish metabolism chamber was constructed with acrylic plastic so that it would passively restrain a 250 to 450-g fish. Gill excretion products were separated from anal excretion products by a rubber septum. Urine was collected through a catheter, and respired carbon dioxide (CO2) was collected in a gas chamber. Channel catfish (Ictalurus punctatus) were given doses of carbon-14 (14C) radiolabeled carboxymethyltartonate (CMT) and linear alkylbenzene sulfonate (LAS) by either intraperitoneal injection, liquid gavage, or food gavage. Improved techniques were developed for catheterizing fish.

Analysis of 14C activity in gill chamber water, anal chamber water, urine, and the CO2 scrubber enabled quantification of the routes and rates of chemical elimination. Essentially, 100 percent of the CMT from the intraperitoneal dose was excreted within 4 days, 85 percent in the urine with the remainder in the anal and gill chamber waters and the CO2 scrubber. A greater portion of total LAS excretion showed in the anal and gill chambers, with urine still being the most important route of elimination. The rate of chemical elimination was greatest in the urine during the first 48 h.
An Evaluation of the Protection Provided by Textile Fabrics Against High-Energy Electrical Flashovers: Design of Test Apparatus
Authors: King MW , Menzies RW , Doupe BE , Mathur RM , Gole AM
Published: March 2009

Utility workers can be exposed to an acute flammability hazard when they are working close to an arcing fault or flashover from electrical equipment or power lines. At the present time it is not possible to recommend the type of protective clothing that should be worn in these circumstances, because no standard flammability test method is available to measure the ability of textile fabrics and other laminae to provide heat and flammability protection against large heat fluxes originating from electrical flashovers. The objective of this study has been to develop such a standard laboratory test method. The design of a test facility that generates arcs under controlled conditions is described. The results of preliminary testing are reported. They demonstrate the validity and reliability of the method as well as indicating those variables that need to be controlled when performing the test.
Laboratory Method for Evaluating the Secondary Hazard Potential of Avicides and Rodenticides to Nontarget Birds and Mammals
Authors: Holler NR , Lefebvre PW
Published: March 2009

A method was developed to determine the secondary hazard potential of avicides and rodenticides to nontarget wild or domestic birds and mammals. Evaluation of this hazard is not adequately covered by existing American Society for Testing and Materials (ASTM) Standards. Our report describes a laboratory method which may be used. Criteria for selection of nontarget test species and minimum laboratory maintenance requirements and conditioning are discussed. The test includes a pretreatment period during which the test animals are conditioned to feed upon the target species, a 7-day treatment period during which test animals are fed target species killed with the test pesticide as applied in the field, and a 14-day post-treatment period during which test animals are observed for signs of intoxication. All test animals undergo necropsy at death or, for survivors, at the end of the post-treatment period. Selected tissues are sectioned and histopathological effects are determined. This method has been used in twelve tests of four avicides on six species of birds and mammals.
Field Method for Evaluation of Rodenticides for Control of Microtus pinetorum in Apple Orchards
Authors: Byers RE
Published: March 2009

A pine vole population censusing technique using whole apples for measuring rodent activity (apple-indexing) levels in the evaluation of rodenticide treatments in orchards is described in detail in this paper. Its use in combination with exhaustive dead trapping at the termination of experiments has provided a rapid and reliable method for making comparisons between treatments. The apple-indexing technique uses the consumption of strategically placed apples as a means of censusing the vole activity in the animals' runway system. This method requires little equipment, does not depend on highly skilled labor, and allows the researcher to evaluate large numbers of plots relatively rapidly. Making comparisons between as many as ten or more treatments in a randomized complete block design with three or four replications becomes practical. The technique simply gives information on the percent of trees or sites visited by voles in a 24-h period. Throughout the posttreatment period rapid evaluation of the population status of each treatment can be evaluated in 24 h. This rapid evaluation is quite valuable in determining the proper timing for the final dead trapping. A number of experiments over a period of years has shown a high correlation between apple-indexing and dead trapping.
Method for Analysis of Rat Acceptance Data Generated in Anticoagulant Bait Bioassays
Authors: Palmateer SD
Published: March 2009

A possible method for interpreting data generated in rat free-choice bioassays with anticoagulatn rodenticides is described. The method allows a greater freedom in interpretation of parameters of efficacy but has a slight problem in differences in bait acceptance by male and female rats. Basically, analysis is a simple one-tailed t-test comparing percent bait acceptance with a cutoff point. The use of the method is demonstrated with authentic data developed by the U.S. Environmental Protection Agency.