bluuebunny/crossref_metadata_2025 huggingface dataset:
A Review of the Quality of Residual Fuels Supplied to Motorships in the United States
Authors: Cullen WP , Royle D
Published: December 2008

The importance of the diesel engine as a means of propulsion in the marine industry cannot be overstated. In addition, the need for higher quality fuels for use in diesel relative to steam turbine equipment also has been long recognized. The petroleum industry has endeavored to abstract the maximum quantities of “clean” products from the crude barrel by more extensive use of fluid catalytic cracking and visbreaking processes. This trend has resulted in a reduction in the quality of the intermediate fuel oil supplied to the marine industry. The need for quality monitoring of marine fuels has received considerable attention over the past few years.

This paper presents a broad outline of a fuel quality testing program available from the author's company and reviews the data generated over the first two-and-one-half years from the program. Particular attention is paid to the average quality of fuels supplied in the three major geographic areas of the United States—East, Gulf, and West Coasts. The importance of the Western Hemisphere, particularly the United States, in the bunker market relative to other geographic areas is also indicated. Without making direct reference to the various suppliers, it is at once evident that within a particular bunkering port fuel quality from supplier to supplier can vary greatly. The variations of fuel quality supplied at U.S. ports from the British Standards Institution limits is also discussed.
Worldwide Characterization of Marine Fuels
Authors: Burnett MW , Giannini RM , Kuby WC , Modetz HJ , Strucko R , Talbot AF
Published: December 2008

Currently, the U.S. Navy's preferred fuel of all fossil-fueled, surface ship power systems is a middle distillate fuel conforming to the requirements of MIL-F-16884H, Fuel, Naval Distillate (NATO F-76). In recent years, the Navy has been finding it more difficult to obtain F-76, especially in foreign ports. In order to address the potential problem of reduced F-76 availability and to begin planning for the introduction of synthetic fuels such as shale oil products, the Energy Research and Development Office of the David W. Taylor Naval Ship Research and Development Center commissioned a shipboard fuels flexibility study. The overall objective of this program is to develop a comprehensive strategy for using a broadened specification fuel on board Navy ships.

This paper presents a summary of work performed to characterize commercial marine fuels from various countries around the globe. Since the marine fuels marketplace is the most likely source of alternate fuels to be used by the Navy, characterization of the fuels in this marketplace is a necessary step in the development of a broadened fuel specification. Fuels of primary (near term) interest are marine gas oils and heavy marine gas oils; those of secondary interest are marine diesel fuels and intermediate fuel oils.
The Past and Future of Navy Ship Fuels
Authors: Lynn NF , White EW , Boyle JF , Layne RP
Published: December 2008

Today's Navy ship propulsion fuel has evolved from coal used to generate steam in the pre-World War I fleet through several residual fuel oils to the present Naval Distillate Fuel suitable for powering boilers, diesels, and gas turbines. The Navy's mission imposes unique requirements upon its shipboard fuel. The fuel must be suitable for use in any of the various ship propulsion systems found in Navy ships (boiler-steam turbine, diesel, and gas turbine systems). Further, the fuel must be suitable whether the particular ship is operating in the Arctic or in tropical waters, or whether the ship is in quiet transit or is conducting battle maneuvers. The fuel also must remain suitable for use whether it has been in storage for a short or long time. These special operating requirements necessitate the specification of more chemical and physical property limitations than are required for normal commercial fuels. Naval Distillate Fuel delivered to the Navy during the 1979 to 1982 period showed a slight but definite trend toward poorer quality with respect to such properties as cetane number, storage stability, carbon residue, and gravity. A survey among suppliers of Navy fuel together with forecasts by industry members of the U.S. delegation to the Quadripartite Navies Information Exchange Program indicated that a general worsening of middle distillate fuel quality can be expected through the year 2000 A.D. Heavier crudes containing higher levels of sulfur and yielding larger volumes of residuum will necessitate greater use of cracking processes to produce the increasing demand for middle distillate fuels, which are expected to reach 40% of the refinery product slate by 2000 A.D. Engine designs will evolve to accommodate the poorer quality fuel and the subsequent increased engine maintenance requirements.
Marine Bunker Fuel Treatment: A Key to Quality Problems?
Authors: Orme AP , Langer AJ , Swinden AE
Published: December 2008

When it was first realized that marine diesel engines could operate successfully with residual fuel oils, there was already the concurrent acceptance of the need for fuel precleaning. Subsequently, there have been many changes in cleaning equipment and operational procedures. While some of these changes may have apparently improved the lot of the marine engineer, arguably they have not been a step forward in protecting engines. In addition, alternatives to traditional procedures have been proposed (and tried), not all of which have been altogether successful. This paper reviews past, present, and possible future fuel cleaning procedures, with particular reference to poorer quality fuel oils. The effects of incorrect fuel treatment are illustrated and recommendations given on how to optimize fuel cleaning arrangements. Proposals are put forward on the direction in which future development might best proceed.
Investigations of Combustion Properties of Liquid Fuels in a Constant Volume Bomb
Authors: Fiskaa G
Published: December 2008

At the Marine Technology Centre in Trondheim, Norway, a “constant volume bomb” has been used since 1980 in the studies of ignition and combustion properties of liquid fuels.

These investigations have been performed in parallel with similar research activities on diesel engines. However, this test rig enables us to carry out far more detailed research on the behavior of liquid fuel sprays in a heated and pressurized combustion chamber.

A variety of sensors are installed, giving information on ignition delay, combustion intensity, and length of combustion. All data are collected and processed by a computerized data acquisition system. In addition, high-speed camera techniques are used to visualize the spray combustion process.

The main object of this research is to establish a correlation between fuel composition—especially for heavy residual fuels—and its ignition and combustion properties.

In establishing the fuel composition, different chromatographic methods together with conventional fuel analysis data are being used. A large number of fuel qualities ranging from light distillates via a variety of heavy residual fuels to Solvent Refined Coal II have been investigated, and typical test results showing the observed differences in ignition and combustion for various fuel types are presented.

Through contact with shipowners and engine builders, we have obtained access to heavy fuel samples that have caused operational problems and engine damages on board ships. Through tests on the just mentioned equipment with these “problem” fuels, we observe “normal” heavy fuels. These deviations as observed in the test rig may give an explanation of the problems encountered in service. Conventional fuel analysis data do not in these cases give an indication that operation on these fuels might lead to operational disturbances.
Development of Evaluation Methods for Stability of Marine Fuels
Authors: Nomura H , Nagasawa T , Yoshida E
Published: December 2008

This study was conducted for the development of marine fuels stability evaluation methods that most closely predict actual performance. The NOC spot test, which is based on the ASTM spot test and modified for wider application, was used in the investigation. Comparisons were made between the more widely known evaluation methods [Shell hot filtration test, Mobil centrifuge test, ASTM Method for Thermal Stability of U.S. Navy Special Fuel Oil, D 1661-64 (1977), and microscopic observation] and the NOC spot test, and fairly good correlations were found. In regard to performance tests, a purifier test and a filter test were carried out using laboratory apparatus that simulated actual field performance, and the spot rating of the NOC spot test correlated with both the amount of purifier sludge and the strainer clogging rate. The stability of fuels during tank storage was remarkably influenced by a scale effect in laboratory tank storage tests. V/S was the appropriate parameter for scaling the laboratory tests, where V was the volume of the fuel stored and S was the surface area of the fuel in contact with air.
Fire Performance Standards for Buildings
Authors: Marchant EW
Published: December 2008

A building is described as a multifunctional agent of environmental change that has to achieve adequate and acceptable performance so that a safe and comfortable environment will result for any human activity. The 14 aspects of whole building performance are listed and examples of advantageous and disadvantageous interactions are offered. Fire safety performance interacts with all other aspects and is distinguished by not being part of the day-to-day environment. All fire safety problems cannot be solved by the application of conventional elements of fire safety technology, and, therefore, the performance approach to fire safety is important as more flexibility in the selection of solutions becomes possible. The identification of relative values of the components of fire safety is an important problem, and these values change according to building type. Performance profiles and levels of acceptability are discussed. Difficulties associated with the measurement of fire safety performance are discussed, and the selection of appropriate appraisal techniques is emphasized. The control of fire safety standards by governmental officials and private professionals is examined, and mention is made of the possible introduction of self-regulation for continuing fire safety standards in buildings.
Future Directions for Modeling the Spread of Fire, Smoke, and Toxic Gases
Authors: Jones WW
Published: December 2008

In recent years there has been considerable interest in the growth of fires and the subsequent movement of smoke and toxic gases in multicompartment structures. This activity is motivated by the need to understand and predict the environmental conditions which occur as a fire develops and spreads. Much of the attention has focused on the development of numerical models which are able to make reasonably accurate predictions from the onset of ignition. Most of the effort has centered on the control volume or zone model approach. While this approach loses some of the detailed analysis available from a fully differential model, such as the velocity profile in a vent, much is gained by the reduction in the number of equations to be solved for each compartment.

As with other types of models, the basic equations to be solved include conservation of mass and energy. These equations are usually recast into predictive equations for temperature, pressure, and volume (layer thickness). An almost universal approximation is that the transient pressure term (dP/dt) is not a significant process in energy transfer. One reason for this approximation is the assumption that an algebraic equation is easier and faster to solve than a differential equation.

We have rederived the zone model equations for the usual two-layer model, retaining the transient pressure term. This allows us to recast the equations in a simpler form which is symmetric for the “upper” and “lower” layers.

We have found this form of the equations to be computationally faster. Also, the transient nature of the equations can be seen in the stability of these equations as well as in the stability of physical processes such as flame puffing and flashover.

We have constructed a multicompartment model using a framework discussed in the paper. Testing this model has been done using experimental results discussed in the paper. These comparisons, plus current calculations and timings for the various models, are presented.
Stochastic Modelling of Fire Growth
Authors: Ramachandran G
Published: December 2008

This paper presents a framework for modelling the growth of fire in a building as a stochastic phenomenon. After discussing the probability distributions of duration of burning and damage, a state transition model involving four states is proposed for describing the progressive stage of fire development (and extinguishment) within a room. This model is based on data furnished by fire brigades in the United Kingdom for fires extinguished in each state during each time period since ignition. It is explained how, by applying “extreme value” technique to these data, approximate values can be obtained for a probability distribution of duration of burning in each state and for probabilities of transition from one state to another. Four materials ignited first in the bedroom of a dwelling are used as examples.
The Need and Availability of Test Methods for Measuring the Smoke Leakage Characteristics of Door Assemblies
Authors: Cooper LY
Published: December 2008

This paper identifies and places into perspective relevant information that would assist in focusing future research and development on test methods to measure the smoke leakage characteristics of door assemblies. The concept of smoke compartmentation is introduced and developed. The importance of cross-door pressure differential in establishing the performance of door assemblies in fire-generated environments is discussed. Door assembly performance then is related to life safety, in general, and to the design of compartments of safe refuge, in particular. The entire discussion suggests a listing of required door assembly test methods and, finally, leads to a review of the availability and development status of existing and potential future test method candidates.
Applications of Sprinkler Technology—Early Suppression of High-Challenge Fires with Fast-Response Sprinkler
Authors: Yao C
Published: December 2008

Recent advances in sprinkler technology research, confirmed with large-scale fire tests, have demonstrated the feasibility of the early suppression of high-challenge fires with a few large-drop sprinklers when fast-response sprinkler links used.

In principle, early fire suppression is determined by the proper balance of three important factors: (1) convective heat release rate at sprinkler response (c); (2) actual delivered density (ADD), the sprinkler discharge actually penetrating the fire plume; and (3) required delivered density (RDD), the quality of water required to suppress fire growth. At the instant of sprinkler operation, a successful early suppression system must be able to provide sufficient ADD with the first few sprinklers operated in excess of the RDD. The faster the sprinkler response, the lower the convective heat release rate at sprinkler operation, the higher the ADD, the lower the RDD, and the easier it will be to achieve early suppression.

Factory Mutual Research Corp. has initiated an intensive program to define and verify the early suppression criteria which can be used as a base for the preparation of approval and application standards, and the development of new ESFR (early suppression fast response) sprinklers by the sprinkler manufacturers. An overview of the ESFR program is presented in this paper.
Prevention of Water Damage in Asphalt Mixtures
Authors: Kennedy TW
Published: December 2008

This paper summarizes the findings of a six-year study of moisture damage of asphalt mixtures, which was conducted at The University of Texas at Austin. The objectives of the study were to define the nature and severity of moisture damage in asphalt pavement mixtures, develop techniques to identify mixtures that are moisture susceptible, and develop recommendations to eliminate or minimize the problem. While this study has primarily focused on problems and mixtures in Texas, additional mixtures and experience from other areas in North America were considered. The study involved laboratory investigations, including the evaluation of mixtures subsequently used in construction, a field evaluation of methods of treating asphalt mixtures with hydrated lime, and an evaluation of actual pavement mixtures that exhibited moisture damage.

The majority of the work utilized the wet-dry indirect tensile test (Lottman), the Texas freeze-thaw pedestal test, and the Texas boiling test, which are discussed with respect to their ability to estimate moisture susceptibility of asphalt-aggregate mixtures. The results obtained for a variety of antistripping agents, including hydrated lime and silanes, are summarized, along with the results of a field experiment to evaluate methods for using hydrated lime. Finally, recommendations are made with regard to methods of alleviating moisture damage, including methods of treating moisture susceptible aggregate with hydrated lime.
Requirements of a New Multiaxial Fatigue Testing Facility
Authors: Found MS , Fernando US , Miller KJ
Published: December 2008

A new multiaxial fatigue testing facility is described. It can strain a thin-walled tubular specimen in three independently controlled loading modes by the use of torsion, axial load, and internal and external pressure. Any stress state having a principal stress ratio between equibiaxial (λ = +1) and torsion (λ = −1) with any orientation of the maximum principal stress and the specimen axis can be chosen, with a maximum principal stress of 700 MN/m2. The significance of specimen geometry is examined in relation to multiaxial fatigue testing and the design of a suitable specimen is discussed. Test data for a 1 Cr-Mo-V steel are presented to show the variation in multiaxial fatigue results for similar stress states obtained using different test systems and specimen geometries. The possibility of undertaking wider investigation of the effects of anisotrophy and cumulative damage is discussed.
The Use of Anisotropic Yield Surfaces in Cyclic Plasticity
Authors: Harvey SJ , Toor AP , Adkin P
Published: December 2008

An anisotropic plasticity approach is used to determine the plastic strains developed in two mechanical ratchetting processes, (a) thin-walled tubes subjected to cyclic plastic shear strain and a sustained axial stress, and (b) thin-walled tubes subjected to cyclic plastic tension and compression with a sustained steady hoop stress. The anisotropic plastic potential includes linear terms which enables Bauschinger effects to be incorporated in the general approach. The coefficients, representing the state of anisotropy, are expressed in terms of the uniaxial and shear yield stresses of the material and can be easily determined from simple tests.

Results are presented showing the cyclic properties developed, together with the results of uniaxial tests showing the development of anisotropic material properties due to axial and hoop strain accumulation.

Using the anisotropic material data, yield surfaces are developed and used to predict the axial and hoop strain within a cycle of plastic strain for the mechanical ratchetting processes. The justification for using equi-plastic strain surfaces is discussed, and the results are compared with those obtained using current or instantaneous yield surfaces.

The results presented indicate that the latter approach is more appropriate, but more material data are required in order to test its validity for other loading systems.

The problems associated with developing realistic yield surfaces for the period immediately after cyclic stress reversal is discussed together with the influence of micro residual stresses.
Effect of Biaxial Loads on the Static and Fatigue Properties of Composite Materials
Authors: Jones DL , Poulose PK , Liebowitz H
Published: December 2008

This paper presents the results of several series of tests performed primarily to determine the effect of biaxial loads on the mechanical properties of specimens made from four graphite/epoxy laminates. Static strength, fatigue life, and residual strength tests were performed on a cruciform type of specimen containing a center hole. The parameters varied in these tests were the applied load biaxiality, hole diameter, and laminate layup.

The test results showed that the hole diameter had a limited influence on the static strength, when the strength was based on the net section area. The applied load biaxiality appeared to have a significant influence on both the fracture path and the magnitude of the failure load. For the quasi-isotropic [0,±45,90]ns laminates, the static strength increased by a factor of 1.44 as the biaxiality was increased from zero to unity and the fracture path rotated from 90° to the principal loading axis to approximately 45° to it. Although fewer tests were performed on the anisotropic [02,±45]ns laminates, the biaxial influence appeared to be insignificant. For some fatigue tests, increasing the biaxiality decreased the fatigue life, while for others the fatigue life was increased. This behavior appears to be governed by material anisotropy, in which certain directions (that is, perpendicular to each layer) exhibit increased sensitivity to fatigue damage. The decreasing lifetimes appeared to be associated with the rotation of the primary failure plane to coincide with one of the relatively weaker directions.
Designing for High-Cycle Biaxial Fatigue Using Surface Strain Records
Authors: McDiarmid DL
Published: December 2008

A method of designing for high-cycle biaxial fatigue using surface strain records is proposed. The irregular strain records are first idealized to cycles of constant amplitude to enable a first estimate of long-life capability to be made from allowable surface strain envelopes. These are developed from a criterion of failure under biaxial fatigue based on material bending and twisting fatigue properties. Methods of determining likely crack growth directions are also proposed. Important parameters to be considered in refining the initial approximate analysis are discussed.
Biaxial Fatigue of Inconel 718 Including Mean Stress Effects
Authors: Socie DF , Waill LA , Dittmer DF
Published: December 2008

Biaxial fatigue tests were conducted on Inconel 718 specimens at room temperature. Thin-walled tubular specimens were subjected to tension, torsion, and combined tension and torsion loading in strain control. Two strain ratio's Rε = 0 and Rε = −1.0, were investigated. Effective strain amplitudes of 1.0 and 0.5% were employed and resulted in fatigue lives ranging from 103 to 104 cycles. Fatigue lives were determined in terms of life to 0.1 and 1.0-mm cracks as well as specimen failure. Fatigue lives were correlated in terms of the Lohr and Ellison parameter for plastic strain which is based on the plane of maximum shear strain that causes the crack to grow into the thickness of the specimen and the normal strain to that plane. Good correlation was also obtained for the Kandel, Brown, and Miller parameter which is based on maximum shear strain and the normal strain to the maximum shear plane. Mean stress effects for the Rε = 0 tests were observed. These data could be correlated with the Rε = −1 data by introducing a mean stress term in the parameters which were then combined with the Coffin-Manson equation for estimating fatigue lives. Data on 24 tests correlated within a factor of 1.5 on life when fatigue lives were determined on the basis of 1-mm cracks.
Fatigue Life Predictions for a Notched Shaft in Combined Bending and Torsion
Authors: Tipton SM , Nelson DV
Published: December 2008

As part of a cooperative research program on biaxial fatigue of the Society of Automotive Engineers (SAE), this paper reports progress to date in the evaluation of methods for predicting fatigue life of a round-bar specimen (1045 steel) with a shoulder fillet, subjected to fully reversed bending, torsion and combined bending and torsion, inphase and 90° out of phase.

First, test data from the literature on multiaxial fatigue behavior of notched specimens are reviewed. Factors influencing that behavior (for example, notch stress state and type of notch geometry) are discussed, as are approaches for correlating the data.

Next, a number of different methods for predicting life to “crack initiation” (millimetre sized cracks) are compared with test data for the SAE specimen. The methods are: (a) elastically calculated notch maximum shear and octahedral shear stress criteria based on nominal stresses and fatigue notch factors, (b) maximum shear and octahedral shear strain criteria, (c) a cyclic plastic work approach, and (d) a criterion based on amplitudes of maximum shear strain and of normal strain on the plane of maximum shear. Methods (b) through (d) utilize measured notch strains. Advantages and shortcomings of the methods are discussed.

Measured notch bending and torsional shear strains are compared to values estimated by simplified elastic-plastic analyses which investigate both use of Neuber's rule and the assumption of total strain invariance (that is, notch strain concentration factor equal to an elastic stress concentration factor.)
Fatigue Under Severe Nonproportional Loading
Authors: Jordan EH , Brown MW , Miller KJ
Published: December 2008

In order to extend our understanding to more generalized and practical cyclic loading conditions, severe nonproportional loading has been studied. Tension-torsion, low-cycle fatigue tests were performed on 1Cr-Mo-V steel at room temperature by applying intermittent axial half cycles. Tests with different loading paths but the same amplitudes of maximum shear strain and normal strain across the maximum shear plane were conducted. Different fatigue lives resulted from different loading paths even when amplitudes were held constant. Additional tests showed that the elimination of the compressive half cycles did not change fatigue life which suggest that the compressive half cycles were nondamaging. The principal implication of the work is that successful methods for predicting nonproportional loading must be selected from models which can show loading path sensitivity. Several models with this feature are discussed, and a procedure for predicting endurance from continuous cycling tests is proposed.
Biaxial Low-Cycle Fatigue of Cr-Mo-V Steel at 538°C By Use of Triaxiality Factors
Authors: Marloff RH , Johnson RL , Wilson WK
Published: December 2008

Low-cycle strain-controlled hold-time fatigue tests were performed on 1Cr-1Mo-¼V rotor steel at 538°C under uniaxial and plane-strain biaxial states of stress. Plain strain was produced by use of a blunt notched compact tension specimen. An inelastic finite-element analysis was used to relate strain at the base of the notch to the notch opening displacement. The results showed reasonable correlation by use of von Mises effective elastic and plastic strain components, with the latter modified by a function of the triaxiality factor. Published results for Cr-Mo-V steel at room temperature and elevated temperature for various biaxial stress conditions were examined in terms of the triaxiality factor-effective strain approach. Good correlation was obtained between predicted and measured life.
The Determination and Interpretation of Thermally Promoted Crack Initiation and Growth Data and Its Correlation with Current Uniaxial Design Data
Authors: Marsh DJ , Charlesworth FDW
Published: December 2008

In high-temperature components, secondary stresses are often applied by surface thermal fluctuations that may be sufficient to cause crack initiation and propagation and they may be also accompanied by primary loads. Since the code endurance design lines are based on isothermal uniaxial fatigue data in air, a series of tests have been conducted to study the crack initiation and growth behavior of Type 316 stainless steel under conditions of thermal fatigue in air from a bulk temperature of 650°C.

In general the observed crack initiation correlated with isothermal fatigue data relevant to temperatures towards the lower end of the surface thermal cycle temperature range indicating that the tensile plastic strain was the most important component of the initiation process. For tests without a primary load the crack growth rates in the inner fully elastic regions of the specimens correlated with calculated stress-intensity factors but again relevant to isothermal data for lower temperatures than the specimen bulk temperature. The crack growth rates observed in the plastic surface regions gave a good correlation with total strain range. A test having a surface strain range of half the isothermal fatigue endurance limit showed that limited crack propagation was possible in defected material at such low strain ranges. The addition of primary end loads gave little effect on the crack initiation behavior but did increase the crack growth rates to give an offset in the correlation with total strain range, which increased with increasing primary load.
Evaluation of Filamentous Algae as Biomonitors of Metal Accumulation in Softwater Lakes: A Multivariate Approach
Authors: Bailey RC , Stokes PM
Published: December 2008

Algae from artificial substrates were collected from 36 softwater lakes in four geographic areas of central Canada. Determination of aluminum, manganese, cadmium, copper, nickel, lead, and zinc were made on the algae, water, and sediment. Sediment nutrients, water pH, alkalinity, and conductivity were also measured.

One objective of the study was to evaluate algae as biomonitors of metals. Another was to determine the levels of metals in water and sediments as they related to other environmental variables. A multivariate approach was used to analyze the data statistically.

As pH decreased, metal concentration in water and algae increased. Sediment metals were unrelated to water pH, but were positively related to sediment organic level and algal metals. Sediment metals were approximately ×1000 the metal concentrations in water, whereas algal metals were 1000 to ×10 000 greater than water levels.

An evaluation is made of algae as biomonitors of acid-stressed lakes. Their role in metal cycling in aquatic systems is identified as an area for future research.
A Study of the Reliability of Daphnia Acute Toxicity Tests
Authors: Lewis PA , Weber CI
Published: December 2008

Acute toxicity tests using Daphnia magna or D. pulex have been employed for many years to determine the toxicity of effluents and toxic substances. However, the many factors that may affect the results of such tests have received little attention. Sequential, repetitive tests were conducted with the reference toxicants sodium dodecyl sulphate (SDS), sodium pentachlorophenate (PCP), and cadmium (Cd) to determine the single laboratory precision of acute 48-h toxicity tests using D. magna and D. pulex, and the effects of feeding on toxicity. The sensitivity of Daphnia to pH shock was also examined. Control survival was 90% or better in 84% of the tests, and 80% or better in 89% of the tests. Survival of controls in tests where the organisms were fed was slightly higher than when they were not fed. The precision of the method, expressed as the relative standard deviation (percent coefficient of variation or CV) of the 48-h LC50, for each reference toxicant, SDS, PCP, and Cd, was 43.8, 35.7, and 20.9% for D. pulex and 28.9, 10.4, and 72.4% for D. magna, respectively. No statistically significant differences (P = 0.05) were observed in 48-h LC50 values obtained from paired tests with fed and unfed D. pulex exposed to PCP or Cd, or with D. magna exposed to SDS. However, the 48-h LC50 values were significantly different for fed and unfed D. magna exposed to PCP or Cd. D. pulex and D. magna were equally sensitive to SDS and PCP, but D. magna was significantly more sensitive to Cd than D. pulex, even though D. magna was tested in water of much greater hardness. Sudden changes in pH of not more than two pH units in the range of pH 5 to 9 resulted in no mortality over a six-day period.
Effects of Small Fish Predation on Microcosm Community Bioassays
Authors: Harrass MC , Taub FB
Published: December 2008

Fish predation has been recognized to influence community composition and structure, but has not been represented in experimental community tests of chemical effects. To investigate the feasibility of including vertebrate predation in 65-L microcosms, four species of small fish (Gasterosteus aculeatus, Cottus asper, Poecilia reticulata, and Pimephales promelas) were tested. These studies suggest that predation can be included in moderately sized microcosms only if exposure is restricted either by limiting the time of fish presence or by allowing the fish access to a limited portion of the microcosm. Predation was simulated by filtration of fixed proportions of the microcosms; no major changes were observed, which suggests that microcosm communities can tolerate removal of at least 25% of selected zooplankton populations per week. Fish predation did not alter the ability to detect direct effects of a selective algicide (streptomycin) on the algae, but did reduce the ability to detect indirect effects on cladoceran and ostracod populations.
Comparative Toxicity of Whole and Liquid Phase Sewage Sludges to Marine Organisms
Authors: Fava JA , Gift JJ , Maciorowski AF , McCulloch WL , Reisinger HJ
Published: December 2008

The chemical composition and acute toxicity of whole digested municipal sewage sludges from twelve water pollution control plants were collected, fractionated, and analyzed. The chemical composition and acute toxicity of whole sewage sludges were compared with those of liquid sewage sludge phases. The chemical constituents analyzed included nutrients, conventional parameters, and U.S. Environmental Protection Agency consent decree priority pollutants. Results indicated that most toxic constituents were associated with suspended solids and were therefore dramatically reduced in the liquid phase sludge fractions. Despite the dramatic reduction of metals, pesticides, and other organic compounds in the liquid sludge phases, there was a distinct trend towards equivalent phase toxicity to Atlantic silversides (Menidia menidia) and grass shrimp (Palaemonetes pugio). However, whole sludges were generally more toxic to mysids (Mysidopsis bahia) than were the liquid phase sludges. Evidence to support the hypothesis that ammonia may be the major contributor to overall toxicity of the sewage sludges tested is presented and discussed.
A Method of Assessing the Toxicity of Contaminated Freshwater Sediments
Authors: LeBlanc GA , Surprenant DC
Published: December 2008

A test method was developed to assess the toxicity of freshwater dredged sediments. Toxicity of contaminated sediments was detected by monitoring survival and growth of fathead minnows (Pimephales promelas), emergence and egg hatchability of midges (Paratanytarsus parthenogenica), survival and reproduction of daphnids (Daphnia magna), and changes in microorganism populations. All organisms were exposed for 21 days in an apparatus that recirculated water through a compartment containing the sediments. In addition, a ranking scheme was proposed with which bulk sediment analyses for chemical contaminants could be condensed into a single value termed the hazard index. The hazard index was calculated for each sediment sample and was indicative of the degree of chemical contamination of the sediment. Sediments were classified as highly polluted, moderately polluted, or relatively nonpolluted, based on their hazard index. Eighty-six dredged sediment samples were tested. All biological parameters measured, except midge egg hatchability, were instrumental in detecting toxicity associated with the sediments. Effects were observed with 74% of the highly polluted sediments, 38% of the moderately polluted sediments, and 36% of the relatively nonpolluted sediments. The sublethal parameters measured were important indicators of toxicity.
A Statistical Test Procedure for Effluent Toxicity Screening
Authors: Mowery PD , Fava JA , Claflin LW
Published: December 2008

This paper discusses the screening of effluent toxicity by comparing survival proportions between effluent-treated and control groups of test organisms. If the effluent is nontoxic, survival proportions should be similar for both groups. However, because of differences in sensitivity of individual test organisms, these proportions will not necessarily be identical. Furthermore, the number of organisms surviving from test to test will vary, even though identical effluent samples and identical laboratory procedures are used for all tests. This paper describes a statistical test for determining when effluent and control group survival proportions are significantly different, thereby indicating a potentially toxic effluent. The paper emphasizes the statistical power of the test for detecting effluents of various toxicities. It also evaluates the probability that an effluent will be incorrectly judged to be toxic.

The four key statistical parameters that determine the usefulness of the test are described: statistical power (i.e., the probability of correctly recognizing a toxic effluent); Type 1 error rate (i.e., the probability of incorrectly judging an effluent to be toxic); effect size (i.e., the true but unknown difference between effluent and control long-run survival proportions); and sample size. (Graphs showing the relationships between these four parameters are included.) As the number of organisms used in the test is increased, the power of the test also increases. An experimental design procedure using this test and the statistical power-sample size tradeoff is also described.
Isolation and Chemical Characterization of Petroleum Refinery Wastewater Fractions Acutely Lethal to Daphnia magna
Authors: Reece CH , Burks SL
Published: December 2008

The object of this study was to isolate and chemically characterize the most acutely toxic fraction of a petroleum refinery wastewater. Daphnia magna static bioassays were used to characterize the relative toxicity of each fraction. Steam stripping the wastewater concentrated the toxicity in a volatile fraction. Activated carbon filtration removed the toxicity but cation exchange did not, indicating that organics are the toxic agents. Methylene chloride extraction of the volatile portion at pH > 11 followed by silica gel column chromatography resulted in an aromatic residue which was acutely toxic when dissolved in culture water. The combination of selected fractionation followed by Daphnia bioassays of each fraction determined the characteristics of the most toxic fraction to be steam volatile, base-neutral, and aromatic. Eleven compounds (polycyclic aromatic hydrocarbons) with a total concentration of 1100 µg/L and accounting for 28% of the total peak area of the chromatogram were identified in the aromatic fraction by a gas chromatograph/mass spectrometer (GC/MS). The mass spectra of the unidentified compounds indicated that they were probably nonhalogenated heterocyclics with molecular weights of 180 to 300, containing nitrogen, oxygen, or sulfur atoms. Some of the unidentified compounds appeared to be hydroxylated forms of the parent compounds which were identified.
An Overview of Biological Effects Testing in Puget Sound, Washington: Methods, Results, and Implications
Authors: Chapman PM , Dexter RN , Kocan RM , Long ER
Published: December 2008

There are relatively few broad-scale studies in which the toxicity (including mutagenicity) of complex contaminant mixtures found in the marine environment has been directly tested. The authors recently completed a series of biological effects studies in Puget Sound, Washington, which involved testing the toxicity of sediments from a variety of sites including heavily industrialized embayments and reference and control areas. Areas chosen for testing encompassed gradients of chemical contamination ranging from lightly to heavily impacted. The following tests were done: (1) acute lethality to a marine fish species (stickleback) and two invertebrate species (an oligochaete and an amphipod); (2) sublethal effects on the respiration rate of an oligochaete species; (3) effects on mitosis of fish cells in culture; (4) lethal and sublethal effects on oyster larvae; (5) lethal and sublethal effects on surf smelt eggs and larvae; (6) lethal and sublethal effects on a polychaete's life-cycle; and (7) in vitro fish cell reproduction studies. Up to 97 sites were investigated, and one or more tests were applied to sediments from each site.

The results indicated that sediments collected from areas shown by other studies to be contaminated with a variety of toxic chemicals were capable of causing lethal and sublethal effects to tested biota in the laboratory. There was good correspondence among the results of the different tests. Sediments from badly contaminated areas overall were the most toxic, while those from the least contaminated areas were the least toxic. Data from field and laboratory studies performed by others with fish and benthos supported the geographic trends observed here. Together, the data from this and other studies have shown effects at the subcellular, cellular, organ, organism, and assemblage levels in parts of Puget Sound.

Data on the biological responses are presently being correlated with complimentary chemical data as an initial step to determine possible causes. Meanwhile, the data from this biological effects study and previously performed contaminant surveys are being used to prioritize areas in Puget Sound for alternative remedial actions. Implications to the affected biota are discussed.
Extrapolating from the Laboratory to the Field: How Uncertain Are You?
Authors: Suter GW , Barnthouse LW , Breck JE , Gardner RH , O'Neill RV
Published: December 2008

A methodology for assessing toxic effects of chemicals on fish should be able to begin with an emission rate, an LC50, and a description of the receiving system and generate an estimate of the likelihood of reductions in fish populations. This process is a series of extrapolations, each with an associated variance. The LC50 must be extrapolated from the test species to the species of interest, to life-cycle toxicity, to long-term toxicity in the field, to changes in population size due to direct toxic effects and, finally, to the combined direct and indirect toxic effects. Similarly, the emission rate must be converted into an effective environmental concentration in an imperfectly known hydrologic, chemical, physical, and biological system. In this paper we summarize some data and methods for making these extrapolations and indicate sources of uncertainty in each stage of the analysis.
Bioavailability of Trace Metals in Natural Waters
Authors: O'Donnel JR , Kaplan BM , Allen HE
Published: December 2008

Current data on the toxicity of metals to aquatic organisms show effect levels over many orders of magnitude of total metal concentrations. Thus it appears that the bioavailability of metals is not related to this parameter. Only a fraction of the metal present is related to the amount “seen” by the organism. From solution, toxicity is a function of the concentration of the free metal ion and some hydrolyzed species. From sediments, metal availability is not well understood, although recent work has indicated that metal bound in specific sediment compartments or phases may be the toxic form.

Bioavailability can be predicted from knowledge of the speciation of metal in an aqueous system. Currently, two approaches are used to study speciation in solution and sediment: fractionation and titration.

This paper examines the relation between water quality and the availability of metals to organisms. The chemistry and measurement of metal species should be used as the basis for reviewing bioassay results. Further research needs to be conducted to elucidate the portion of sediment-bound metal which is bioavailable. Problems in the interpretation of bioassay results for natural waters arise from the addition of metal in excess of the capacity of organic ligands for complexation and in not allowing reactions to attain equilibrium.
Biological Degradation of Complex Iron Cyanides in Natural Aquatic Systems
Authors: Cherryholmes KL , Cornils WJ , McDonald DB , Splinter RC
Published: December 2008

Iron cyanide complexes have been considered to be very stable when protected from light. However, it was observed in the current study that when aqueous solutions of potassium hexacyanoferrate (III) were seeded with bacteria, concentrations of free cyanide were detected within four days which were as much as 88 times greater than those observed in sterile control solutions. This is significant in terms of aquatic toxicology, since the 200 to 250 µg/L LC50 value for free cyanide for many fish species was exceeded.
Use of Statistical Information to Improve Compatibility Between the Various Components of the Water Quality Based Approach
Authors: Jaworski NA , Mount DI
Published: December 2008

During the past two decades, implementation procedures in wastewater management often resulted in a large margin of safety being incorporated into the use of water quality criteria for the protection of aquatic life and its uses. Wasteload allocation design conditions, such as the use of seven-day, ten-year low flow, gave assurances of instream concentrations well below the water quality criteria a large percentage of time. Present-day economic conditions and the increasing cost of advanced wastewater treatment are necessitating a re-examination of how water quality criteria are being used in the water quality based approach for establishing effluent limitations.

The relationships between water quality criteria and other components of the water quality based approach are identified. The need for a better defined and more consistent use of statistical information is suggested not only in the development of water quality criteria but also for the entire water quality based approach. Intensity, duration, and frequency of occurrence (return period) appear to be three common statistical parameters of the six-step water quality based approach. Research is identified which, if successful, would allow water quality managers better insight in determining pollutant exposures that more adequately simulate receiving water conditions resulting from variable stream flows, wastewater discharge rates, and pollutant concentrations.
A Dynamic Hybrid Finite-Element Analysis for Interfacial Cracks in Composites
Authors: Kuo A-Y , Wang S-S
Published: December 2008

The research herein develops an accurate and efficient numerical technique, finite-element method with hybrid stress crack-tip elements, for analyzing interfacial crack problems under dynamic loading. Hybrid stress crack-tip elements for interfacial cracks of composite laminates are formulated by setting the first variation of a hybrid functional equal to zero. During the element formulation, asymptotic solutions around the crack tip are employed for stress and displacement fields within the crack-tip element. Displacements along element boundaries are interpolated independently. Newmark's θ method is used for integrating dynamic equations. Thus, monotonic convergence of the finite-element solutions is guaranteed. Two different kinds of delaminations, open and closed interfacial cracks, under lateral impact are studied. Effects of element size, element aspect ratio, and eigenfunction truncation have been investigated. Transient solutions for (± θ) composites are presented for illustration. Effects of crack sizes and lamination sequences are discussed.