bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of Toxicity Tests in Regulating the Quality of Industrial Wastes in Canada
Authors: Pessah E , Cornwall GM 
Published: March 2009

Federal controls on industrial liquid effluents in Canada are developed through consultative government-industry task forces. These controls are technology based (the best practicable technology) and include chemical parameters and a toxicity (acute lethality) limit.
The toxicity test provides a means of integrating the combined effects of a multitude of chemical constituents, a practical, yet indicated alternative to comprehensive (exhaustive) chemical analyses on the increasingly complex effluents. A simple 96-h mortality bioassay using rainbow trout is presented that is typical of those appearing in Canadian regulations. This, in combination with analysis of a few selected chemical parameters, offers an efficient and effective means of regulating effluent quality at the source.
There is a need for standardized sublethal, rapid-response tests to facilitate greater efficiencies in both routine monitoring and wastewater characterization.
Monitoring, Analysis, and Control of Toxic and Hazardous Materials in the Chesapeake Bay
Authors: Bostater CR , Pepino RV , Roland JV 
Published: March 2009

The Chesapeake Bay Program of the U.S. Environmental Protection Agency, with cooperation and input from the states of Maryland and Virginia, has developed and is now implementing a toxicant plan of action for monitoring, analysis, and control of toxic and hazardous substances in the Chesapeake Bay estuarine system. Six tasks have been identified in the initial plan. They include: 1. Baseline monitoring of water, sediment, and biota for toxic pollutants in order to assess the current state of the Chesapeake Bay. 2. A source assessment of toxic substances in order to estimate the inputs of toxic pollutants to the region. 3. Determination of the fate, transport, and transformation of toxic substances by physical and chemical processes through the estuarine environment. 4. Effects studies to determine toxicity values and water quality criteria for substances that may accumulate in the food chain and that adsorb to sediment particles. 5. Intensive investigations of small watersheds with the goal of deriving a materials balance model for toxic inputs to the system. 6. The submission of recommendations for implementation that are based on technical reports to management and regulatory agencies.
Ideally, data generated from samples taken in the environmental compartments, that is, bottom sediments, interstitial water, benthic flora and fauna, fluid mud, suspended sediment, nekton, plankton, and the atmosphere can allow for the development of a toxicological profile at selected sampling stations, as well as supply the first integrated Bay-wide baseline data base for toxic substances.
The source assessment task involves effluent monitoring for toxic pollutants, non-point source watershed monitoring, and the measurement of tributary inputs of potential hazardous substances.
The rationale for a toxicological profile monitoring approach is described along with the toxicant plan of action.
Effects of UV-B on Algal Growth Rate and Trace Gas Production
Authors: Hannan PJ , Swinnerton JW , Lamontagne RA , Patouillet C 
Published: March 2009

Cultures of Phaeodactylum tricornutum were exposed to combinations of visible and ultraviolet-B (UV-B) light intensities in the laboratory, the ultraviolet light (UV) sources being fluorescent lamps whose peak emission was at approximately 310 nm. Filters of cellulose acetate and Mylar were used to attenuate the UV-B intensity, the latter absorbing all the radiation in the 310 nm region. The growth rates of the algae were calculated from chlorophyll analyses made during the exponential growth of the cultures, and trace gas measurements were made after a fixed time (44 h).
Algal cells exposed to a UV-B flux approximately one-fifth that of average sunlight intensity, with visible light intensities optimal for photosynthesis, underwent a 20 percent reduction in growth rate and were completely inhibited by UV fluxes half that of sunlight. A major finding of the trace gas analyses was that carbon monoxide (CO) formation was relatively constant over the range of UV fluxes imposed. Previous experiments with outdoor exposures had produced CO in concentrations of an order of magnitude higher. It appears that UV-B was not the causative agent for the unsually high CO production resulting from exposure of the algae to sunlight.
Assimilation Efficiency and Clearance of Trichlorobenzenes in Rainbow Trout
Authors: Smith AD , Griffith TJ , Orr DE , Ozburn GW 
Published: March 2009

A unique experimental approach has been applied to a study of the bioaccumulation dynamics in rainbow trout fed a single meal containing trichlorobenzenes (TCBs). The technique involves the incorporation of a radioactive chemical marker in the diet, in addition to the chemical of interest (TCB). The marker chemical permits an estimate to be made of the assimilation efficiency of TCB in food. The assimilation efficiency can then be used, in conjunction with a series of direct analyses for TCB body burdens, to describe tissue clearance dynamics in terms of individual fish.
Trout given a pulse dose meal containing 50 ppm TCB assimilated approximately 61 percent of the chemical. Individual fish were capable of clearing more than 90 percent of the TCB sequestered in their tissues within 174 h after dosing.
Temperature Tolerance Determinations for Daphnia
Authors: Goss LB 
Published: March 2009

First immature instar and adult egg-carrying Daphnia pulex Leydig acclimated from 5 to 30°C, at 5°C intervals, and Daphnia magna Straus acclimated from 5 to 25°C, at 5°C intervals, were instantaneously immersed at 30 and 35°C and observed for mortality. Observations were made at 0.5, 1, 2, 4, and 8 h after immersion and every 8 h thereafter until 95 percent mortality occurred. Twenty organisms were used in each test, and the tests were carried out in temperature-controlled water baths. Filtered lake water was used for culture and testing.
Adult egg-bearing D. pulex and D. magna were more sensitive to the upper lethal temperatures than their respective immature forms, which indicates that mature egg-carrying forms should be used for determining temperature tolerance levels. The results also indicated that organisms held in laboratory cultures for extended time periods at constant temperatures have decreased upper temperature tolerance limits, in comparison with organisms adapted to the fluctuating temperatures of natural environments, which have been laboratory acclimated for shorter time periods.
Shortcomings in the methodologies of previous thermal tolerance studies on zooplankton are discussed, and recommendations are made as to how these methods can be improved.
Dynamic Fracture Analysis of Notched Bend Specimens
Authors: Mall S , Kobayashi AS , Loss FJ 
Published: March 2009

A dynamic finite-element code was used to determine dynamic initiation fracture toughness, KId, in 25.4-mm-thick (1 in.) notched bend specimens of A533B steel and a 15.9-mm-thick (5/8 in.) dynamic tear specimen of 6061 aluminum alloy. These specimen types can reflect varying dynamic fracture response due to differences in test temperature, specimen geometry, and material as well as notch tip sharpness. Measured load-time histories were applied to the tup as modeled by finite elements, and the dynamic stress-intensity factor was computed by a calibrated crack opening displacement procedure. Dynamic stress-intensity factors were also computed by the ASTM Test for Plane-Strain Fracture Toughness of Metallic Materials (E 399-74) using a load based on local dynamic strain measurements and a static K calibration.
Reasonable agreements between measured and computed dynamic strains in the vicinity of the crack tip verified the accuracy of the dynamic finite-element model. The attendant agreement between measured versus computed time-varying dynamic stress-intensity factors also verified, for the first time, the applicability of ASTM E 399-74 for computing dynamic initiation fracture toughness, KId, on the basis of local dynamic strain measurements.
Dynamic Photoelastic Determination of the ˙a-K Relation for 4340 Alloy Steel
Authors: Kobayashi T , Dally JW 
Published: March 2009

A method of direct determination of the instantaneous stress-intensity factor associated with running and arrested cracks in steels has been developed at the University of Maryland. Birefringent coatings have been applied to the proposed ASTM standard crack arrest compact specimens of oil-quenched and tempered 4340 steel. Isochromatic fringe patterns during crack propagation and crack arrest have been photographed successfully with an ultrahigh-speed Cordin camera and specially designed high-intensity and short-duration Xenon lamp system.
In this paper a detailed description of the experimental apparatus, the method of isochromatic fringe analysis technique, and an examination of behavior of the stress-intensity factor during crack propagation and after arrest are presented.
Laboratory Testing and Monitoring of Stray Current Corrosion of Prestressed Concrete in Seawater
Authors: Cornet I , Pirtz D , Polivka M , Gau Y , Shimizu A 
Published: March 2009

Stray current corrosion of prestressed concrete beams was investigated in the laboratory by exposing 40 specimens 6.4 by 6.4 by 122 cm (2.5 by 2.5 by 48 in.), prestressed by a central high-strength steel wire to 1.86 × 109 N/m2 (270 ksi), in seawater. The steel wire was made anodic to a copper cathode, with steel current densities maintained at fixed values between 27 and 915 mA/m2 (2.5 and 85 mA/ft2).
Monitoring was done by measuring steel potential relative to a silver/silver chloride reference electrode with current on, weekly, and with current off, biweekly. Beams were examined visually biweekly; the presence of rust spots and longitudinal cracks was noted, and lengths of cracks were measured, for exposures which ranged between 8 and 83 weeks. After exposure, the prestressing wire was tensioned to failure.
Reductions in breaking strength of 70 percent were observed in 25 weeks' exposure at 915 mA/m2 (85 mA/ft2), with lesser reductions in strength for shorter exposures and lower current densities.
Ampere-hours did not correlate satisfactorily with the reduction in breaking strength of the wire. Potentials measured with current on or off indicated that corrosion was occurring, but gave no quantitative indication of the reduction in breaking strength. Resistance measurements of the electrochemical circuit did not relate to the extent of corrosion damage. Time to change in potential of the prestressing steel did correlate with time for initiation of steel corrosion. Existence and length of longitudinal cracks in the concrete beam did not correlate quantitatively with the reduction in breaking strength of the prestressing steel.
After the tension test, beams were notched lengthwise with a saw and opened. The prestressing wire was then examined to determine the distribution and extent of corrosion. Quantitative estimates of the corroded length were made. Qualitatively, where there was considerable localized corrosion attack, there was great reduction in breaking strength for a given number of ampere-hours' exposure. Where the corrosion attack was well distributed, an equal number of ampere-hours gave less reduction in fracture strength.
Stray electrical currents can cause serious deterioration in the strength of prestressed concrete structures, as measured by testing to destruction. However, none of the methods of monitoring used in this investigation can predict the extent of the damage quantitatively.
Cold Neutron Imaging for Gas Turbine Inspection
Authors: Stewart PAE 
Published: March 2009

Cold neutron radiography has a number of attractive features which make it particularly suitable for solving some specific problems in gas turbine development, connected with fuel, oil or hydraulic systems. Other hydrogenous materials are also rendered clearly visible by this technique.
This paper describes preliminary work to determine image quality using cold neutrons with a range of test objects, including an oil penetrameter, engine accessory components and a full-size static Rolls-Royce ‘Viper’ gas turbine. This work was carried out on the C1 residual cold neutron radiographic beam port at the ‘Herald’ research reactor (5 MW) at the U.K. Atomic Weapons Research Establishment at Aldermaston in June 1975.
Computerized Fluorodensitometry Using a Solid-State Matrix Camera
Authors: Ziskin MC , Philips CM 
Published: March 2009

Conventional televised fluoroscopy enables real-time visualization of dynamically changing structures within the body provided there is adequate radiologic contrast between the object of interest and its immediate surround. Under special conditions, such as in arteriography, injection of a contrast agent into the structure being studied enhances its visualization. Where applicable, greatest contrast enhancement is provided by image subtraction. In our experience, because of the intrinsic noisiness of television (TV), radiologic contrast had to exceed 5 percent for visualization by any of the aforementioned techniques.
In order to measure a 1 percent X-ray transmission variation, we have replaced the vidicon camera with a Reticon solid-state matrix camera. This camera contains a 32 by 32 photodiode array with an intrinsic noise level far below that of standard TV. However, a fixed-pattern pixel noise due to differing pixel sensitivities must be canceled out. This is easily performed by subtraction with a dark-field pixel pattern previously stored in a computer. The frame rate of the camera can be varied from 15 to 100 Hz.
The video signal is digitized and entered into a LINC-8 digital computer for densitometry. The primary use of this system to date has been in the measurement of pulmonary pulsations in monkeys. These pulmonary pulsations are small variations in X-ray transmission through the chest due to the change in blood content of the lungs during each heartbeat. A decrease in the amplitude of pulmonary pulsations is a potentially important diagnostic sign in the clinical evaluation of cardiac failure and in early lung cancer.
Air Infiltration Reduction Through Retrofitting
Authors: Harrje DT , Mills TA 
Published: March 2009

This paper documents and compares the air infiltration levels experienced in five Twin Rivers townhouses before and after retrofit. The technique used to measure air infiltration rates was the tracer gas method, which relied upon automated equipment. Weather data as well as 5-min interval air infiltration measurements were used in the comparisons.
Analysis techniques included multiple regression, polar plotting, stemleaf plotting, and detailed comparisons of infiltration rates as influenced by temperature differences inside-to-outside the dwelling.
The results indicate that: the retrofitted townhouses are noticably less sensitive to wind direction, showing little or no increase in infiltration when the wind directly impinges on building surfaces; the post-retrofit infiltration rates average 36 percent less than the preretrofit data, with individual houses experiencing as much as a 48 percent decrease; and basement and attic retrofitting appear to be very influential in achieving the greatest reductions in air infiltration rates.
Wintertime Infiltration Rates in Mobile Homes
Authors: Goldschmidt VW , Leonard RG , Ball JE , Wilhelm DR 
Published: March 2009

The infiltration in mobile homes can be reduced by treatments such as caulking or adding a special sheathing board material. Present standards set limits on the infiltration rates in mobile homes. Reduction in infiltration rates are accompanied by reductions in heating, ventilating and air-conditioning (HVAC) equipment sizing and operation cost. Unfortunately, there is a general lack of actual field data to determine infiltration rates of mobile homes and the general dependence of infiltration on wind and temperature differences.
A field test setup including two unoccupied mobile homes is described. The facility permits a measure of weather, consumption, infiltration rate, and surface temperatures. Data are now presented comparing the winter performance of the two mobile homes. The homes are identical on all counts except that one is treated with a special sheathing board while the other is caulked. The data indicate a general parabolic dependence of infiltration on wind (and a linear dependence on temperature difference) with consistently lower values of infiltration rate for the board-sheathed home than for the caulked home.
Determination of Polynuclear Aromatic Hydrocarbons in Wastewater from Coal Liquefaction Processes by the Gas Chromatography-Ultraviolet Spectrometry Technique
Authors: Robbins WK , Searl TD , Wasserstrom DH , Boyer GT 
Published: March 2009

One of the classes of compounds that may be present in wastewater from coal conversion plants is polynuclear aromatic hydrocarbons (PAH). Since 13 PAHs containing from three to six condensed rings are on the U.S. Environmental Protection Agency (EPA) list of priority pollutants, an analytical method has been developed for the determination of PAHs in process waters from coal liquefaction processes. This method utilizes the well-established gas chromatography-ultraviolet spectrometry (GC-UV) technique to determine the 13 at the 0.1 ppb (micrograms per litre) level and higher. Isomers and twelve additional PAHs are routinely measured, and the technique may be extended as necessary to cover other compounds as well.
In the method, each wastewater sample is spiked with [14C]phenanthrene, [14C]benz[a]anthracene, and [14C]benzo[a]pyrene prior to extraction with methylene chloride. The methylene chloride phase is then washed with aqueous acid and base to remove phenols, organic acids, and basic nitrogen compounds. The methylene chloride neutrals are then solvent exchanged into cyclohexane, and the cyclohexane phase is extracted with N-methylpyrrolidone (NMP). A PAH-rich fraction suitable for GC-UV measurement is obtained by dilution of the NMP with water and back extraction into isooctane. In the GC-UV measurement step, the PAHs are separated by gas chromatography and the component fractions trapped. After dissolution of the PAHs from the traps, ultraviolet absorption measurements are made for the individual PAHs. Peaks containing the carbon-14 internal standards are assayed for radioactivity, and the ratio of the final to the initial radioactivity is used to quantitate the data.
With this technique, the effect of the coal type and the reaction conditions can be determined. Polynuclear aromatic hydrocarbon analyses of several raw wastewaters obtained from coal liquefaction pilot plants are presented and discussed.
Origin of Carbonaceous Species in the Atmosphere Deduced by Radiocarbon
Authors: Currie L 
Published: March 2009

A review is given of the use of radiocarbon as a direct measure of the relative importance of natural and anthropogenic sources of carbonaceous gases and particles. Through the use of a specially designed, low-level gas proportional counting system, the biospheric (living) carbon fraction has been determined in selected chemical species containing as little as 5 mg of carbon. The species of interest include those that are climatically active and those that have an impact on air quality, such as methane, carbon monoxide, nonmethane hydrocarbons, and carbonaceous particles.
Major factors considered in the interpretation of the radiocarbon data include the chemical and isotopic composition of carbonaceous sources, and natural and man-induced perturbations of biospheric radiocarbon. In order to ensure reliable conclusions, therefore, we have incorporated chemical and size selectivity and data on the recent history of radiocarbon fluctuations. Exploratory studies on selected urban and rural aerosol samples have thus far reflected the dominance of man's activities for the urban locales. This has been seen in the large fossil carbon content of particles from cities having only natural biospheric sources, and in the large biospheric carbon content of urban (Portland, Ore.) particles collected during periods of wood and grass burning.
Measurement advances, including the development of multiple counter systems and accelerator mass spectrometry, promise increased utilization of natural radiocarbon as an environmental tracer, in addition to its application to the rarer atmospheric components.
An Overview of the Use of Short-Term Bioassays in Evaluation of Atmospheric Pollutants
Authors: Waters MD 
Published: March 2009

The screening of complex atmospheric mixtures for potential biological hazard presents special problems in sampling, analysis, and interpretation. Recent efforts emphasize a close coupling of chemical (fractionation) and biological (bioassay) techniques. Most of these studies have been performed on air particulate samples; far less attention has been directed toward vapor-phase and gas-phase samples. The most commonly employed short-term test has been the Ames Salmonella/microsome assay.Current studies on particulate components favor a combination of size-selective sampling with chemical analysis and bioassay, to provide a more direct relationship between the data obtained and the potential inhalation hazard. When possible, multiple agents are identified and bioassayed in carefully defined chemical fractions. Iterative application of bioassay and chemical fractionation thus facilitates identification of individual chemical species that display biological activity.In the area of quantification and interpretation, complex atmospheric mixtures present additional challenges, including the possible masking of mutagenic activity by toxicants contained within the mixture, differential metabolic activation, and detoxification. Important concerns to be addressed in estimating a sample's toxicity include questions of biological availability and dosimetry. Answers to such questions determine our ability to estrapolate in vitro results to the in vivo situation.
Austeno-Ferritic Stainless Steel Castings—A Future Solution to Many Corrosion Problems
Authors: Jōly A 
Published: March 2009

The austeno-ferritic steels are derived from the classical austenitic steels by increasing the percentage of some α-retaining elements (mainly chromium or molybdenum). Because of their two-phase structure, these steels offer a range of particularly interesting properties.
As far as mechanical characteristics are concerned, the yield strength and tensile strength of austeno-ferritic steels are much higher than those of the austenitic grades. Moreover, the austeno-ferritic steels combine very good processing abilities (molding, casting, welding, machining) with excellent resistance against different kinds of corrosion such as pitting, crack, stress, and intergranular corrosion.
In the production of cast valve and pump bodies the austeno-ferritic stainless steels are particularly suitable where difficult problems of corrosion are to be resolved in handling of sulfuric and phosphoric acids, seawater, natural gas, etc.